The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's<0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's≤0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p<0.04). Height loss was inversely correlated with cement fill (p<0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. This article is protected by copyright. All rights reserved.
View details for DOI 10.1002/jor.24127
View details for PubMedID 30117192
BACKGROUND CONTEXT: Lumbosacral ESIs have increased dramatically despite a narrowing of the clinical indications for use. One potential indication is to avoid or delay surgery, yet little information exists regarding surgery rates after ESI.PURPOSE: The purpose of this research was to determine the proportion of patients having surgery after lumbar epidural steroid injection (ESI) for disc herniation or stenosis and to identify the timing and factors associated with this progression STUDY DESIGN/SETTING: This study was a retrospective review of nationally-representative administrative claims data from the Truven Health MarketScan databases from 2007 - 2014.PATIENT SAMPLE: The study cohort was comprised of 179,025 patients (54±15 years, 48% female) having lumbar epidural steroid injections (ESIs) for diagnoses of stenosis and/or herniation.OUTCOME MEASURES: The primary outcome measure was the time from ESI to surgery.METHODS: Inclusion criteria were ESI for stenosis and/or herniation, age ≥18 years, and health plan enrollment for 1 year prior to ESI to screen for exclusions. Patients were followed longitudinally until they progressed to surgery or had a lapse in enrollment, at which time they were censored. Rates of surgery were assessed with the Kaplan-Meier survival curves. Demographic and treatment factors associated with surgery were assessed with multivariable Cox proportional hazard models. No external funding was procured for this research and the authors' conflicts of interest are not pertinent to the present work.RESULTS: Within 6 months, 12.5% of ESI patients underwent lumbar surgery. By 1 year, 16.9% had surgery, and by 5 years, 26.1% had surgery. Patients with herniation had surgery at rates of up to 5 to 7 fold higher, with the highest rates of surgery in younger patients and those with both herniation and stenosis. Other concomitant spine diagnoses, male sex, previous tobacco use, and residence a rural areas or regions other than the Northeastern United States were associated with higher surgery rates. Medical comorbidities (previous treatment for drug use, CHF, obesity, COPD, hypercholesterolemia, and other cardiac complications) were associated with lower surgery rates.CONCLUSIONS: In the long-term, more than 1 out of every 4 patients undergoing ESI for lumbar herniation or stenosis subsequently had surgery, and nearly 1 of 6 had surgery within the first year. After adjusting for other patient demographics and comorbidities, patients with herniation were more likely have surgery than those with stenosis. The improved understanding of the progression from lumbar ESI to surgery will help to better inform discussions regarding the value of ESI and aid in the shared decision making process.
View details for DOI 10.1016/j.spinee.2018.05.034
View details for PubMedID 29959098
View details for DOI 10.1007/s00586-017-5381-3
View details for Web of Science ID 000425292500038
View details for PubMedID 29275521
Background: We previously reported that functional recovery of rats with spinal cord contusions can occur after acute transplantation of neural stem cells distal to the site of injury. To investigate the effects of timing of administration of human neural stem cell (hNSC) distal to the site of spinal cord injury on functional outcomes in an animal model.Methods: Thirty-six adult female Long-Evans hooded rats were randomized into three experimental and three control groups with six animals in each group. The T10 level was exposed via posterior laminectomy, and a moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor (MASCIS, W.M. Keck Center for Collaborative Neuroscience, Piscataway, NJ, USA). The animals received either an intrathecal injection of hNSCs or control media through a separate distal laminotomy immediately, one week or four weeks after the induced spinal cord injury. Observers were blinded to the interventions. Functional assessment was measured immediately after injury and weekly using the Basso, Beattie, Bresnahan (BBB) locomotor rating score.Results: A statistically significant functional improvement was seen in all three time groups when compared to their controls (acute, mean 9.2 vs. 4.5, P=0.016; subacute, mean 11.1 vs. 6.8, P=0.042; chronic, mean 11.3 vs. 5.8, P=0.035). Although there was no significant difference in the final BBB scores comparing the groups that received hNSCs, the group which achieved the greatest improvement from the time of cell injection was the subacute group (+10.3) and was significantly greater than the chronic group (+5.1, P=0.02).Conclusions: The distal intrathecal transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected in the acute, subacute and chronic phases of spinal cord injury (SCI), although the greatest gains appeared to be in the subacute timing group.
View details for DOI 10.21037/jss.2017.10.06
View details for PubMedID 29354733
To determine the presence of infectious microorganisms in the herniated discs of immunocompetent patients, using methodology that we hoped would be of higher sensitivity and specificity than has been reported in the past. Recent studies have demonstrated a significant rate of positive cultures for low virulent organisms in excised HNP samples (range 19-53%). These studies have served as the theoretical basis for a pilot trial, and then, a well done prospective randomized trial that demonstrated that systemic treatment with antibiotics may yield lasting improvements in a subset of patients with axial back pain. Whether the reported positive cultures in discectomy specimens represent true positives is as yet not proven, and critically important if underlying the basis of therapeutic approaches for chronic low back pain.This consecutive case series from a single academic center included 44 patients with radiculopathy and MRI findings of lumbar HNP. Patients elected for lumbar microdiscectomy after failure of conservative management. All patients received primary surgery at a single spinal level in the absence of immune compromise. Excised disc material was analyzed with a real-time PCR assay targeting the 16S ribosomal RNA gene followed by amplicon sequencing. No concurrent cultures were performed. Inclusion criteria were as follows: sensory or motor symptoms in a single lumbar nerve distribution; positive physical examination findings including positive straight leg raise test, distributional weakness, and/or a diminished deep tendon reflexes; and magnetic resonance imaging of the lumbar spine positive for HNP in a distribution correlating with the radicular complaint.The PCR assay for the 16S rRNA sequence was negative in all 44 patients (100%). 95% CI 0-8%.Based on the data presented here, there does not appear to be a significant underlying rate of bacterial disc infection in immunocompetent patients presenting with radiculopathy from disc herniation.
View details for DOI 10.1007/s00586-017-5141-4
View details for PubMedID 28567591
OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.
View details for DOI 10.3171/2016.12.SPINE16969
View details for PubMedID 28430052
In previous studies, Propionibacterium acnes was cultured from intervertebral disc tissue of ~25% of patients undergoing microdiscectomy, suggesting a possible link between chronic bacterial infection and disc degeneration. However, given the prominence of P. acnes as a skin commensal, such analyses often struggled to exclude the alternate possibility that these organisms represent perioperative microbiologic contamination. This investigation seeks to validate P. acnes prevalence in resected disc cultures, while providing microscopic evidence of P. acnes biofilm in the intervertebral discs.Specimens from 368 patients undergoing microdiscectomy for disc herniation were divided into several fragments, one being homogenized, subjected to quantitative anaerobic culture, and assessed for bacterial growth, and a second fragment frozen for additional analyses. Colonies were identified by MALDI-TOF mass spectrometry and P. acnes phylotyping was conducted by multiplex PCR. For a sub-set of specimens, bacteria localization within the disc was assessed by microscopy using confocal laser scanning and FISH.Bacteria were cultured from 162 discs (44%), including 119 cases (32.3%) with P. acnes. In 89 cases, P. acnes was cultured exclusively; in 30 cases, it was isolated in combination with other bacteria (primarily coagulase-negative Staphylococcus spp.) Among positive specimens, the median P. acnes bacterial burden was 350 CFU/g (12 - ~20,000 CFU/g). Thirty-eight P. acnes isolates were subjected to molecular sub-typing, identifying 4 of 6 defined phylogroups: IA1, IB, IC, and II. Eight culture-positive specimens were evaluated by fluorescence microscopy and revealed P. acnes in situ. Notably, these bacteria demonstrated a biofilm distribution within the disc matrix. P. acnes bacteria were more prevalent in males than females (39% vs. 23%, p = 0.0013).This study confirms that P. acnes is prevalent in herniated disc tissue. Moreover, it provides the first visual evidence of P. acnes biofilms within such specimens, consistent with infection rather than microbiologic contamination.
View details for DOI 10.1371/journal.pone.0174518
View details for Web of Science ID 000399351000019
View details for PubMedID 28369127
Cross-sectional cohort analysis of patients with Modic Changes (MC).Our goal was to characterize the molecular and cellular features of MC bone marrow and adjacent discs. We hypothesized that MC associate with biologic cross-talk between discs and bone marrow, the presence of which may have both diagnostic and therapeutic implications.MC are vertebral bone marrow lesions that can be a diagnostic indicator for discogenic low back pain. Yet, the pathobiology of MC is largely unknown.Patients with Modic type 1 or 2 changes (MC1, MC2) undergoing at least 2-level lumbar interbody fusion with one surgical level having MC and one without MC (control level). Two discs (MC, control) and two bone marrow aspirates (MC, control) were collected per patient. Marrow cellularity was analyzed using flow cytometry. Myelopoietic differentiation potential of bone marrow cells was quantified to gauge marrow function, as was the relative gene expression profiles of the marrow and disc cells. Disc/bone marrow cross-talk was assessed by comparing MC disc/bone marrow features relative to unaffected levels.Thirteen MC1 and eleven MC2 patients were included. We observed pro-osteoclastic changes in MC2 discs, an inflammatory dysmyelopoiesis with fibrogenic changes in MC1 and MC2 marrow, and up-regulation of neurotrophic receptors in MC1 and MC2 bone marrow and discs.Our data reveal a fibrogenic and pro-inflammatory cross-talk between MC bone marrow and adjacent discs. This provides insight into the pain generator at MC levels and informs novel therapeutic targets for treatment of MC-associated LBP.
View details for DOI 10.1007/s00586-017-4955-4
View details for PubMedID 28138783
View details for PubMedCentralID PMC5409869
The relationship between intervertebral disc degeneration and chronic infection by Propionibacterium acnes is controversial with contradictory evidence available in the literature. Previous studies investigating these relationships were under-powered and fraught with methodical differences; moreover, they have not taken into consideration P. acnes' ability to form biofilms or attempted to quantitate the bioburden with regard to determining bacterial counts/genome equivalents as criteria to differentiate true infection from contamination. The aim of this prospective cross-sectional study was to determine the prevalence of P. acnes in patients undergoing lumbar disc microdiscectomy.The sample consisted of 290 adult patients undergoing lumbar microdiscectomy for symptomatic lumbar disc herniation. An intraoperative biopsy and pre-operative clinical data were taken in all cases. One biopsy fragment was homogenized and used for quantitative anaerobic culture and a second was frozen and used for real-time PCR-based quantification of P. acnes genomes. P. acnes was identified in 115 cases (40%), coagulase-negative staphylococci in 31 cases (11%) and alpha-hemolytic streptococci in 8 cases (3%). P. acnes counts ranged from 100 to 9000 CFU/ml with a median of 400 CFU/ml. The prevalence of intervertebral discs with abundant P. acnes (≥ 1x103 CFU/ml) was 11% (39 cases). There was significant correlation between the bacterial counts obtained by culture and the number of P. acnes genomes detected by real-time PCR (r = 0.4363, p<0.0001).In a large series of patients, the prevalence of discs with abundant P. acnes was 11%. We believe, disc tissue homogenization releases P. acnes from the biofilm so that they can then potentially be cultured, reducing the rate of false-negative cultures. Further, quantification study revealing significant bioburden based on both culture and real-time PCR minimize the likelihood that observed findings are due to contamination and supports the hypothesis P. acnes acts as a pathogen in these cases of degenerative disc disease.
View details for DOI 10.1371/journal.pone.0161676
View details for PubMedID 27536784
View details for PubMedCentralID PMC4990245
View details for DOI 10.1016/j.spinee.2015.08.058
View details for Web of Science ID 000366655100049
View details for PubMedID 26343242
Prior studies have demonstrated the superiority of decompression and fusion over decompression alone for the treatment of lumbar degenerative spondylolisthesis with spinal stenosis. More recent studies have investigated whether nonfusion stabilization could provide durable clinical improvement after decompression and fusion.To examine the clinical safety and effectiveness of decompression and implantation of a novel flexion restricting paraspinous tension band (PTB) for patients with degenerative spondylolisthesis.A prospective clinical study.Forty-one patients (7 men and 34 women) aged 45 to 83 years (68.2±9.0) were recruited with symptomatic spinal stenosis and Meyerding Grade 1 or 2 degenerative spondylolisthesis at L3-L4 (8) or L4-L5 (33).Self-reported measures included visual analog scale (VAS) for leg, back, and hip pain and the Oswestry Disability Index (ODI). Physiologic measures included quantitative and qualitative radiographic analysis performed by an independent core laboratory.Patients with lumbar degenerative spondylolisthesis and stenosis were prospectively enrolled at four European spine centers with independent monitoring of data. Clinical and radiographic outcome data collected preoperatively were compared with data collected at 3, 6, 12, and 24 months after surgery. This study was sponsored by the PTB manufacturer (Simpirica Spine, Inc., San Carlos, CA, USA), including institutional research support grants to the participating centers totaling approximately US $172,000.Statistically significant improvements and clinically important effect sizes were seen for all pain and disability measurements. At 24 months follow-up, ODI scores were reduced by an average of 25.4 points (59%) and maximum leg pain on VAS by 48.1 mm (65%). Back pain VAS scores improved from 54.1 by an average of 28.5 points (53%). There was one postoperative wound infection (2.4%) and an overall reoperation rate of 12%. Eighty-two percent patients available for 24 months follow-up with a PTB in situ had a reduction in ODI of greater than 15 points and 74% had a reduction in maximum leg pain VAS of greater than 20 mm. According to Odom criteria, most of these patients (82%) had an excellent or good outcome with all except one patient satisfied with surgery. As measured by the independent core laboratory, there was no significant increase in spondylolisthesis, segmental flexion-extension range of motion, or translation and no loss of lordosis in the patients with PTB at the 2 years follow-up.Patients with degenerative spondylolisthesis and spinal stenosis treated with decompression and PTB demonstrated no progressive instability at 2 years follow-up. Excellent/good outcomes and significant improvements in patient-reported pain and disability scores were still observed at 2 years, with no evidence of implant failure or migration. Further study of this treatment method is warranted to validate these findings.
View details for DOI 10.1016/j.spinee.2015.01.003
View details for PubMedID 25579423
View details for DOI 10.1016/j.spinee.2015.01.003
View details for Web of Science ID 000349994900008
Biomechanical human cadaveric study.We hypothesized that increasing compressive preload will reduce the segmental instability after nucleotomy, posterior ligament resection, and decompressive surgery.The human spine experiences significant compressive preloads in vivo due to spinal musculature and gravity. Although the effect of destabilization procedures on spinal motion has been studied, the effect of compressive preload on the motion response of destabilized, multisegment lumbar spines has not been reported.Eight human cadaveric spines (L1-sacrum, 51.4 ± 14.1 yr) were tested intact, after L4-L5 nucleotomy, after interspinous and supraspinous ligaments transection, and after midline decompression (bilateral laminotomy, partial medial facetectomy, and foraminotomy). Specimens were loaded in flexion (8 Nm) and extension (6 Nm) under 0-N, 200-N, and 400-N compressive follower preload. L4-L5 range of motion (ROM) and flexion stiffness in the high-flexibility zone were analyzed using repeated-measures analysis of variance and multiple comparisons with the Bonferroni correction.With a fixed set of loading conditions, a progressive increase in segmental ROM along with expansion of the high-flexibility zone (decrease of flexion stiffness) was noted with serial destabilizations. Application of increasing compressive preload did not substantially change segmental ROM, but did significantly increase the segmental stiffness in the high-flexibility zone. In the most destabilized condition, 400-N preload did not return the segmental stiffness to intact levels.Anatomical alterations representing degenerative and iatrogenic instabilities are associated with significant increases in segmental ROM and decreased segmental stiffness. Although application of compressive preload, mimicking the effect of increased axial muscular activity, significantly increased the segmental stiffness, it was not restored to intact levels; thereby suggesting that core strengthening alone may not compensate for the loss of structural stability associated with midline surgical decompression. This suggests that there may be a role for surgical implants or interventions that specifically increase flexion stiffness and limit flexion ROM to counteract the iatrogenic instability resulting from surgical decompression.Level of Evidence: N/A.
View details for DOI 10.1097/BRS.0000000000000093
View details for PubMedID 24153162
Development of a dynamic stabilization system often involves costly and time-consuming design iterations, testing and computational modeling. The aims of this study were (1) develop a simple parametric model of lumbar flexion instability and use this model to identify the appropriate stiffness of a flexion restricting stabilization system (FRSS), and (2) in a cadaveric experiment, validate the predictive value of the parametric model.Literature was surveyed for typical parameters of intact and destabilized spines: stiffness in the high flexibility zone (HFZ) and high stiffness zone, and size of the HFZ. These values were used to construct a bilinear parametric model of flexion kinematics of intact and destabilized lumbar spines. FRSS implantation was modeled by iteratively superimposing constant flexion stiffnesses onto the parametric model. Five cadaveric lumbar spines were tested intact; after L4-L5 destabilization (nucleotomy, midline decompression); and after FRSS implantation. Specimens were loaded in flexion/extension (8 Nm/6 Nm) with 400 N follower load to characterize kinematics for comparison with the parametric model.To accomplish the goal of reducing ROM to intact levels and increasing stiffness to approximately 50 % greater than intact levels, flexion stiffness contributed by the FRSS was determined to be 0.5 Nm/deg using the parametric model. In biomechanical testing, the FRSS restored ROM of the destabilized segment from 146 ± 13 to 105 ± 21 % of intact, and stiffness in the HFZ from 41 ± 7 to 135 ± 38 % of intact.Testing demonstrated excellent predictive value of the parametric model, and that the FRSS attained the desired biomechanical performance developed with the model. A simple parametric model may allow efficient optimization of kinematic design parameters.
View details for DOI 10.1007/s00586-013-2934-y
View details for Web of Science ID 000327899100006
View details for PubMedID 23955312
There has been increasing interest in spinous process tension band devices, as distinct from spinous process spacers and plates. The purpose of this study was to load spinous processes caudally at L-4 and cranially at L-5 parallel to the long axis of the spine in a biomechanical model of tension band loading. The goal was to provide normative data for the design of a spinous process tension band device after varying degrees of surgical decompression and across varying bone mineral densities (BMDs).Fresh-frozen L4-5 lumbar vertebrae pairs were divided into 3 surgical groups: intact, midline-sparing decompression (laminotomy and medial facetectomy), and midline decompression with foraminotomy (one-half of spinous process resected, laminotomy, and medial facetectomy). After decompression, specimens were disarticulated into isolated L-4 and L-5 vertebrae. Each vertebra was loaded to failure in a caudal (L-4) or cranial (L-5) direction parallel to the long axis of the spine via a 6-mm-wide strap looped around the spinous process. Failure strength and mode were recorded.Seventeen L-4 and L-5 lumbar vertebrae were tested from 17 cadavers. There were 10 male (59%) and 7 female (41%) cadavers, with a mean age of 66.6 ± 16.5 years (range 41-100 years) and a mean BMD of 1 ± 0.23 g/cm(2) (range 0.66-1.34 g/cm(2)); the mean is expressed ± SD throughout. For data analysis, specimens were grouped into those with no or midline-sparing decompression (Group 1: 11 of 17) and those with midline decompression (Group 2: 6 of 17). At L-4, the mean failure strength for Group 1 was 453 ± 162 N, and for Group 2 it was 264 ± 99 N (p = 0.02; Cohen's d = 1.4). At L-5, the mean failure strength for Group 1 was 517 ± 190 N, and for Group 2 it was 269 ± 184 N (p = 0.02; Cohen's d = 1.3). There was no significant difference in failure strength between the intact and midline-sparing decompression groups at L-4 (p = 0.91) or L-5 (p = 0.41).Across specimens with a wide range of BMDs, midline-sparing decompression was not found to decrease the mean failure strength of the L-4 and L-5 spinous processes (453 and 517 N, respectively), whereas midline surgical decompression decreased the failure strength of these processes (264 and 269 N, respectively) in a biomechanical model of tension band loading relevant to the design of a tension band device.
View details for DOI 10.3171/2012.3.SPINE11392
View details for Web of Science ID 000305589000010
View details for PubMedID 22559276
Closed C2 fractures commonly occur after falls or other trauma in the elderly and are associated with significant morbidity and mortality. Controversy exists as to best treatment practices for these patients.To compare outcomes for elderly patients with closed C2 fractures by treatment modality.We retrospectively reviewed 28 surgically and 28 nonsurgically treated cases of closed C2 fractures without spinal cord injury in patients aged 65 years of age or older treated at Stanford Hospital between January 2000 and July 2010. Comorbidities, fracture characteristics, and treatment details were recorded; primary outcomes were 30-day mortality and complication rates; secondary outcomes were length of hospital stay and long-term survival.Surgically treated patients tended to have more severe fractures with larger displacement. Charlson comorbidity scores were similar in both groups. Thirty-day mortality was 3.6% in the surgical group and 7.1% in the nonsurgical group, and the 30-day complication rates were 17.9% and 25.0%, respectively; these differences were not statistically significant. Surgical patients had significantly longer lengths of hospital stay than nonsurgical patients (11.8 days vs 4.4 days). Long-term median survival was not significantly different between groups.The 30-day mortality and complication rates in surgically and nonsurgically treated patients were comparable. Elderly patients faced relatively high morbidity and mortality regardless of treatment modality; thus, age alone does not appear to be a contraindication to surgical fixation of C2 fractures.
View details for DOI 10.1227/NEU.0b013e3182446742
View details for Web of Science ID 000303390400013
View details for PubMedID 22157549
An 80-year-old female with a history of osteoporosis was evaluated for sudden onset axial low back pain with bilateral lower extremity weakness, hyperreflexia, pain, urinary retention, and decreased rectal tone. Computed tomography of the lumbar spine revealed L1 compression fracture, retropulsion of bone causing spinal canal compromise with associated severe central canal stenosis. Following cement kyphoplasty of L1 with polymethyl methacrylate, the patient developed tachycardia and dyspnea. Chest radiograph and computed tomographic pulmonary angiogram revealed a large collection of hyperdense material within the right lower lobe pulmonary artery, consistent with pulmonary cement emboli. Management and imaging are discussed.
View details for DOI 10.1111/j.1533-2500.2011.00446.x
View details for Web of Science ID 000297109500007
View details for PubMedID 21435160
Retrospective chart review.To identify predictors of 30-day complications after the surgical treatment of spinal metastasis.Surgical treatment of spinal metastasis is considered palliative with the aim of reducing or delaying neurologic deficit. Postoperative complication rates as high as 39% have been reported in the literature. Complications may impact patient quality of life and increase costs; therefore, an understanding of which preoperative variables best predict 30-day complications will help risk-stratify patients and guide therapeutic decision making and informed consent.We retrospectively reviewed 200 cases of spinal metastasis surgically treated at Stanford Hospital between 1999 and 2009. Multiple logistic regression was performed to determine which preoperative variables were independent predictors of 30-day complications.Sixty-eight patients (34%) experienced one or more complications within 30 days of surgery. The most common complications were respiratory failure, venous thromboembolism, and pneumonia. On multivariate analysis, Charlson Comorbidity Index score was the most significant predictor of 30-day complications. Patients with a Charlson score of two or greater had over five times the odds of a 30-day complication as patients with a score of zero or one.After adjusting for demographic, oncologic, neurologic, operative, and health factors, Charlson score was the most robust predictor of 30-day complications. A Charlson score of two or greater should be considered a surgical risk factor for 30-day complications, and should be used to risk-stratify surgical candidates. If complications are anticipated, medical staff can prepare in advance, for instance, scheduling aggressive ICU care to monitor for and treat complications. Finally, Charlson score should be controlled for in future spinal metastasis outcomes studies and compared to other comorbidity assessment tools.
View details for DOI 10.1097/BRS.0b013e318206cda3
View details for Web of Science ID 000294207500005
View details for PubMedID 21358481
There is mounting evidence that the currently available techniques for the diagnosis of discogenic low back pain are insufficiently accurate-this may explain some of the variability in outcomes of surgery for this important clinical problem. New diagnostic methods are needed to address this diagnostic issue; improvements here may do as much to improve overall patient outcomes as improvements in surgical treatment methods.To compare the results of standard pressure-controlled provocative discography (PD) to those of the functional anesthetic discogram (FAD) in a series of patients presenting with chronic low back pain and considering surgical treatment.Prospective clinical series in an academic spinal surgical practice.Fifty-two patients presenting with chronic low back pain; mean age 45 years (range, 24-70 years); 28 women, 24 men; and 25% in workman's compensation program.Oswestry, visual analog scale for back pain, distress and risk assessment method psychometric analysis, demographic data, magnetic resonance imaging scan of lumbar spine. During provocative discogram: pressurization at pain, pain level, and concordancy. During FAD: position or activity used to elicit typical pain, baseline pain level before injection, during injection, at 5, 10, and 20 minutes after the injection, and substance injected.Standard pressure-controlled PD was performed, followed by (in positive cases or in patients with clinical features and imaging studies felt to be highly suggestive of symptomatic disc degeneration) the FAD test-an assessment of the response to injection of a low dose of local anesthetic into the disc during a position productive of the patient's typical pain.Discordant results of the two tests were noted in 46% of the patients in the series. Of them, 26% of patients with positive PD had negative findings on the FAD test; 16% had positive findings at a single level only, whereas the provocative discogram had been positive at two or more levels; 4% had new positive findings on the FAD test.We have presented the results of a new diagnostic technique in 52 patients with chronic low back pain presumed discogenic in origin that was designed to help differentiate between symptomatic and asymptomatic disc degeneration. The findings of the test differed from those of standard pressure-controlled PD in 46% of the cases reported on here. Further studies are needed to demonstrate the clinical utility of the test.
View details for DOI 10.1016/j.spinee.2011.07.021
View details for Web of Science ID 000295772900018
View details for PubMedID 21868288
A consecutive case series from a single center of patients undergoing primary microdiscectomy for lumbar herniated nucleus pulposus (HNP) who received microbiologic laboratory culture of excised disc material.To determine the prevalence of positive bacterial cultures in the disc material of immunocompetent patients without diabetes mellitus or other immune compromise.The intradiscal space is a physiologically tenuous environment in terms of oxygen tension, pH, and vascularity. This space may be susceptible to indolent infections with an unknown effect on the pathogenesis of HNP.This case series included 52 patients with radiculopathy and magnetic resonance imaging positive for HNP who elected for lumbar microdiscectomy after failure of conservative management. All patients received primary surgery at a single spinal level in the absence of diabetes mellitus, systemic steroid use, chemotherapy, other immune compromise, or prior lumbar surgery. Excised disc material was sent for routine bacterial culture. No special culture techniques were used to improve the yield of positive cultures.Cultures were positive in 10 patients (19.2%). Propionibacterium acnes was the sole organism isolated in 7 (13.5%), with Peptostreptococcus and Staphylococcus species accounting for the remainder. There were 24 women (46.2%) and 28 men (53.8%) with a mean age of 43.9 years (SE 1.8). Duration of symptoms was greater than 12 weeks in 35 patients (67.3%). Onset of symptoms was insidious in 22 patients (42.3%), sudden in 16 (30.8%), and the history was unclear in the remainder. Prior epidural steroid injection was received by 17 patients (32.7%), and 11 patients had a history of smoking (21.2%). None of these variables was significantly different in patients with positive and negative cultures (P >0.05).P. acnes was isolated by routine laboratory culture of excised disc material in 13.5% of immunocompetent patients undergoing primary single level discectomy for radiculopathy with lumbar HNP; other organisms were isolated in 6% of patients.Diagnostic level of evidence III.
View details for DOI 10.1097/BSD.0b013e3182019f3a
View details for Web of Science ID 000293173600011
View details for PubMedID 21150662
Surgery for spinal metastasis is a palliative treatment aimed at improving patient quality of life by alleviating pain and reversing or delaying neurologic dysfunction, but with a mean survival time of less than 1 year and significant complication rates, appropriate patient selection is crucial.To identify the most significant prognostic variables of survival after surgery for spinal metastasis.Chart review was performed on 200 surgically treated spinal metastasis patients at Stanford Hospital between 1999 and 2009. Survival analysis was performed and variables entered into a Cox proportional hazards model to determine their significance.Median overall survival was 8.0 months, with a 30-day mortality rate of 3.0% and a 30-day complication rate of 34.0%. A Cox proportional hazards model showed radiosensitivity of the tumor (hazard ratio: 2.557, P<.001), preoperative ambulatory status (hazard ratio: 2.355, P=.0001), and Charlson Comorbidity Index (hazard ratio: 2.955, P<.01) to be significant predictors of survival. Breast cancer had the best prognosis (median survival, 27.1 months), whereas gastrointestinal tumors had the worst (median survival, 2.66 months).We identified the Charlson Comorbidity Index score as one of the strongest predictors of survival after surgery for spinal metastasis. We confirmed previous findings that radiosensitivity of the tumor and ambulatory status are significant predictors of survival.
View details for DOI 10.1227/NEU.0b013e318207780c
View details for Web of Science ID 000287242300036
View details for PubMedID 21311295
Retrospective clinical series.Description of alternative technique for the harvesting of posterior iliac crest bone graft (ICBG) and assessment of associated morbidity.Although posterior ICBG operations are common, they are often reported to result in significant morbidity. A recent emphasis on the morbidity of ICBG has helped to fuel the costly growth in clinical use of alternatives, such as bone morphogenetic protein-2. Many studies have reported a variety of complications related to iliac crest donor sites, but the most common reported morbidity is pain and/or decreased sensation over the ICBG site.This study is a retrospective review of all patients in the practice of the senior author (T.F.A.) during the study period who received a lumbar fusion with autogenous bone harvested from the posterior iliac crest and accessed by the surgical approach described. Outcomes were assessed by a pain questionnaire determining the site of pain and its magnitude on visual analog scale. Pain on the harvested side was compared with that on the contralateral side, and overall procedure satisfaction was assessed. Statistical analysis was performed using analysis of variance, the Pearson chi2 test, and the Student t test. Any value of P < 0.05 was considered significant.Of 120 patients eligible for the study, 92 patients (77%) were available for follow-up. The patients were interviewed on an average of 24 months (+/-14 months) after their operation. The vast majority of patients (88%, n = 81) had no significant difference in pain or had less pain over the ICBG site than the contralateral side. Eleven patients (12%) experienced significantly greater pain at the ICBG site than over the contralateral side (visual analog scale difference >1). There were 7 patients (8%) in the series with significantly greater pain over the contralateral iliac crest than at the ICBG site. The likelihood of significant pain over the harvested ICBG site was not statistically greater than the likelihood of contralateral iliac crest pain (P = 0.23). One patient (1%) had sensory loss in the superior cluneal nerve distribution. There was 1 patient with an infection that involved the ICBG site and required irrigation and debridement and intravenous antibiotics. Seventy-two patients (78%) stated that they were very satisfied with the operation, 13 (14%) were somewhat satisfied, and 7 (8%) were not satisfied.Although it is difficult to directly compare our results to those reported in other studies, we conclude that the rate of significant chronic sequelae related to this method of harvesting bone from the posterior iliac crest is low. Our findings may be due to the avoidance in this technique of disruption of the gluteal musculature and preservation of the lateral wall of the ilium. The methods used in other studies to estimate the prevalence of chronic pain related to posterior iliac crest bone grafting after lumbar spinal surgery may grossly overestimate this prevalence.
View details for DOI 10.1097/BRS.0b013e3181cabf69
View details for Web of Science ID 000278817200010
View details for PubMedID 20551786
To determine if thoracic facet joints may be a significant secondary pain generator in patients with compression fractures. Traditionally, pain from vertebral compression fractures has been attributed to vertebral body itself. Compression fractures have been shown to increase thoracic kyphosis and thereby increase the thoracic flexion moment; these changes eventually increase the shear stress on the posterior elements.We present a small case series of patients with thoracic compression fractures managed with intra-articular facet injections.Tertiary care academic medical center.Two patients with thoracic compression fractures.The subjects received fluoroscopically guided thoracic facet steroid injections for pain management.Change in verbal analog pain score.Patients with thoracic compression fractures received significant long-lasting relief after receiving fluoroscopically guided intra-articular injections.Facet joints may be abnormally stressed due to the increasing thoracic flexion moment in anterior compression fractures, which may serve as a secondary pain generator; intra-articular facet blocks may be an alternative to vertebroplasty.
View details for Web of Science ID 000283989800011
View details for PubMedID 21029349
Interspinous process devices represent an emerging treatment for neurogenic intermittent claudication resulting from lumbar spinal stenosis. Most published descriptions of the operative technique involve treatment of patients in the modified lateral decubitus knee-chest position (modified lateral decubitus), and yet many surgeons have begun to perform the procedure in various prone positions. The patient's positioning on the operating room table seems likely to influence resting interspinous distance, and thus implant sizing and possibly the risk of intraoperative spinous process fracture. The intersegmental lumbar effect of variants on operative prone positioning compared with the modified lateral decubitus position has not been studied.We performed this study to determine the comparative differences in interspinous distance and intersegmental angulation effected by the lateral decubitus knee-chest position and the variants on prone positioning used in practice.Experimental human radiographic study.Twenty healthy male volunteers with a mean age of 43.6+/-10.8 years (range, 24-63), without chronic back pain, symptoms of neurogenic claudication, or history of lumbar surgery were enrolled.Interspinous distance, anterior and posterior disc heights, disc angulation were measured on PACS monitor.Lateral X-rays were taken of the lower lumbar spine in each of four different surgical positions (modified lateral decubitus, Andrews frame, Wilson frame, and Jackson frame). Statistical analysis was performed on the resultant data points to assess the significance of the effect of the position of the subject on intersegmental spacing and angulation.The 20 enrollees had a mean age of 43.6+/-10.8 years (range, 24-63). The mean interspinous distance at the L4-L5 level was greatest on the Andrews table (23.5+/-8.3mm) followed by the modified lateral decubitus position (19.6+/-5.1mm), the Wilson frame (15.6+/-4.6mm), and then the Jackson frame (10.1+/-4.7mm; significantly less than all other positions p< or =.036). Mean segmental extension at the L4-L5 level was least in the modified lateral decubitus position (-0.1 degrees +/-2.9 degrees ); this was statistically similar to extension on the Andrews table (1.5 degrees +/-4.7 degrees , p=1.0), but significantly less than that recorded on the Wilson frame (4.6 degrees +/-3.1 degrees , p<.001), and also significantly less than that recorded on the Jackson frame (p< or =.001). Similar differences in segmental measurements were observed at L3-L4.Prone positioning of patients in flexion on the operating table using the Andrews table or Wilson frame resulted in similar lumbar interspinous distance compared with the modified lateral decubitus position. Prone positioning on the Jackson frame resulted in statistically less interspinous distance than all other positions. Positioning on the Andrews table resulted in similar segmental angulation to the modified lateral decubitus position. Extrapolation from these data, obtained in healthy males younger than the typical age of patients treated with interspinous distraction devices, should clearly be done with caution. However, it seems reasonable to suggest that performing these procedures in the prone position using the Andrews table (greatest interspinous distance) is unlikely to result in the placement of significantly undersized implants, or significantly increase the force required to insert an implant.
View details for DOI 10.1016/j.spinee.2009.04.002
View details for Web of Science ID 000268565500009
View details for PubMedID 19482515
More than one-third of patients with cancer have vertebral metastases found at autopsy. Primary and metastatic tumors to the spinal column can lead to pain, instability, and neurologic deficit. Symptomatic lesions are most prevalent in the thoracic spine (70%), followed by the lumbar spine (20%) and cervical spine (10%). Lesions in larger vertebral bodies tend to be asymptomatic given the increased ratio between the diameter of the spinal canal and the traversing nerve roots.
View details for DOI 10.1016/j.ocl.2008.09.011
View details for Web of Science ID 000262295500009
View details for PubMedID 19064058
The diagnostic evaluation of patients with presumed discogenic low back pain is controversial; recent studies have brought the specificity of the traditional technique, provocative lumbar discography, into question. One of the explanations for the relative lack of predictability in treatment outcomes for patients with discogenic low back pain may be a corresponding lack of certainty in the diagnosis.A new diagnostic technique is described for the evaluation of patients with presumptive discogenic low back pain; the cases of 3 patients in whom the technique was used are presented.Case report; university practice.A technique is described in which an anaesthetic catheter is placed into putative symptomatic lumbar discs, the patient elicits his or her typical pain via a position or activity, and anaesthetic or placebo is delivered to the disc. The effect of the injected substance on the patient's pain is then noted.In one patient, the new test was confirmatory of the results of the provocative discogram; in two patients, the test results were divergent.These case studies and technical description are presented as a first step in examining this method of preoperative assessment. Further study of the technique will allow us to make more definitive recommendations with regards to its validity and utility.Level 4 - Case Series.
View details for DOI 10.1016/SASJ-2007-0123-NT
View details for PubMedID 25802610
Prospective, 5-year, cohort study of working subjects.To assess whether the occurrence of common minor trauma events affects the risk of developing serious low back pain (LBP) and LBP disability in subjects with and without degenerative changes to the lumbar spine.Although some theories suggest that minor traumatic events in combination with preexisting degenerative changes commonly cause significant structural injury to spinal segments and serious LBP illness, no prospective data exist on the relationship of minor trauma, detailed structural changes, and outcome measures of serious LBP episodes and occupational disability.Two hundred subjects without clinical LBP problems were recruited, and underwent baseline clinical and imaging studies. Every 6 months, subjects completed a scripted, algorithm-based interview assessing interval back pain episodes, severity, medical treatment, occupational disability, and the subject's perceived relation of this LBP episode to any preceding event. If a serious LBP episode clinically required a new magnetic resonance examination, the follow-up imaging was obtained and compared to baseline for interval changes.There was no association of minor trauma to adverse LBP events. For each 6-month study interval, the risk of developing a serious LBP episode was 2.1% unassociated with minor trauma and 2.4% following minor trauma (P = 0.59). Neither the frequency of minor trauma events nor the reported severity of the event correlated with adverse outcomes. Subjects with advanced structural findings were not more likely to become symptomatic with minor trauma events than with spontaneously evolving LBP episodes. Follow-up magnetic resonance imaging evaluating new serious LBP illness rarely revealed new clinically significant findings. Age and sex-adjusted prediction models, including abnormal psychometric testing, smoking, and compensation issues, accurately identified 80% of serious LBP events and 93% of LBP disability events.In this study cohort, minor trauma does not appear to increase the risk of serious LBP episodes or disability. The vast majority of incident-adverse LBP events may be predicted not by structural findings or minor trauma but by a small set of demographic and behavioral variables.
View details for Web of Science ID 000242576200009
View details for PubMedID 17139225
Magnetic resonance (MR) imaging is frequently used to evaluate first-time episodes of serious low back pain (LBP). Common degenerative findings are often interpreted as recent developments and the probable anatomic cause of the new symptoms. To date no prospective study has established a baseline MR status of the lumbar spine in subjects without significant LBP problems and prospectively surveyed these subjects for acute changes shortly after new and serious LBP episodes. This method can identify new versus old MR findings possibly associated with the acute symptomatic episode.To determine if new and serious episodes of LBP are associated with new and relevant findings on MRI.Prospective observational study with baseline and post-LBP MRI monitoring of 200 subjects over 5 years.Clinical outcomes: LBP intensity (visual analogue scale), Oswestry Disability Index, and work loss. MRI outcomes: disc degeneration, herniation, annular fissures, end plate changes, facet arthrosis, canal stenosis, spondylolisthesis, and root impingement.200 subjects with a lifetime history of no significant LBP problems, and a high risk for new LBP episodes were studied at baseline with physical examination, plain radiographs, and MR imaging. Subjects were followed every 6 months for 5 years with a detailed telephone interview. Subjects with a new severe LBP episode (LBP>or=6/10,>1 week) were assessed for new diagnostic tests. New MR imaging, taken within 6 to 12 weeks of the start of a new LBP episode, was compared with baseline (asymptomatic) images. Two independent and blinded readers evaluated each baseline and follow-up study.During the 5-year observation period of 200 subjects, 51 (25%) subjects were evaluated with a lumbar MRI for clinically serious LBP episodes, and 3/51 (6%) had a primary radicular complaint. These 51 subjects had 67 MR scans. Of 51 subjects, 43 (84%) had either unchanged MR or showed regression of baseline changes. The most common progressive findings were disc signal loss (10%), progressive facet arthrosis (10%), or increased end plate changes (4%). Only two subjects, both with primary radicular complaints, had new findings of probable clinical significance (4%). Subjects having another MR were more likely to have had chronic pain at baseline (odds ratio [OR]=3.19; 95% confidence interval [CI] 1.61-6.32), to smoke (OR=5.81; 95% CI 1.99-16.45), have baseline psychological distress (OR 2.27; 95% CI 1.15-4.49), and have previous disputed compensation claims (OR=2.35; 95% CI 0.97-5.69). Subjects involved in current compensation claims were also more likely to have an MR scan to evaluate the LBP episode (risk ratio=4.75, p<.001), but were unlikely to have significant new findings. New findings were not more frequent in subjects with LBP episodes developing after minor trauma than when LBP developed spontaneously.Findings on MR imaging within 12 weeks of serious LBP inception are highly unlikely to represent any new structural change. Most new changes (loss of disc signal, facet arthrosis, and end plate signal changes) represent progressive age changes not associated with acute events. Primary radicular syndromes may have new root compression findings associated with root irritation.
View details for PubMedID 17088193
The surgical treatment for low-grade isthmic spondylolisthesis in adults with intractable lumbar pain is usually spinal fusion. It has been postulated that anterior column reconstruction may be relatively advantageous in those patients with unstable slips.To compare the early and medium term treatment efficacy of two common fusion techniques in isthmic spondylolisthesis.Prospective controlled trial comparing single-level posterior-lateral instrumented fusion with combined anterior and posterior-lateral instrumented fusion in sequential matched cohorts of patients with radiographically unstable isthmic spondylolisthesis.Primary outcome measure of success was an Oswestry Disability Index (ODI)
View details for PubMedID 17088191
Ex vivo biomechanical study using osteoporotic cadaveric fractured vertebral bodies.To investigate the behavior of fractured osteoporotic vertebral bodies treated with either vertebroplasty or kyphoplasty under repetitive loading conditions.Vertebroplasty and kyphoplasty are newer alternatives for the treatment of osteoporotic vertebral fractures. Loading conditions that can lead to fractures treated with these methods will likely be encountered subsequently; as such, it is important to understand differences in the biomechanical behavior of the resultant constructs.There were 7 pairs of osteoporotic T8 and T10 vertebral bodies cyclically loaded to produce a vertebral compression fracture. Of each pair, one was assigned to the kyphoplasty group and the other to the vertebroplasty group. After treatment, specimens were cyclically loaded to 100,000 cycles, between 20% and 70% of the predicted failure load.Height was restored with kyphoplasty, but the vertebral bodies showed significant height loss during cyclic loading. Vertebroplasty specimens had higher compression stiffness and smaller height reduction.Under repetitive loading conditions, fractured vertebral bodies treated with kyphoplasty were initially taller, but because of a progressive loss of height during loading, the resulting constructs were shorter after 100,000 cycles than those treated with vertebroplasty.
View details for Web of Science ID 000239832500010
View details for PubMedID 16915092
This is a prospective study of the validity of a positive test result in provocative lumbar discography for the diagnosis of "discogenic pain."To investigate the hypothesis that provocative discography by strict criteria accurately identifies a low back pain illness due to a primary disc lesion.According to the Sackett and Haynes criteria for establishing diagnostic test validity, no test without a gold standard external standard can be meaningfully applied. Provocative discography as a test for determining "discogenic pain" has, to date, not been compared against a gold standard. Absent a gold standard reference, there can be no validity assessment or systematic improvement of test accuracy. This is the first study to apply an external gold standard evaluation of the diagnostic validity of discography in any manner.Over a 5-year period using a strict enrollment protocol, 32 patients with low back pain and a positive single-level low-pressure provocative discogram, underwent spinal fusion. Subjects with known patient selection comorbidities were excluded. Generic surgical limitations/morbidity were controlled by comparison to the clinical outcomes of a strictly-matched cohort of 34 patients having a well-accepted single-level lumbar pathology (unstable spondylolisthesis). Treatment success was compared between groups.In the control-spondylolisthesis group, 23 of 32 patients (72%) met the highly effective success criteria compared with 8 of 30 in the presumed discogenic pain cohort (27%). The proportion of patients who met the "minimal acceptable outcome" was 29 of 32 (91%) in the spondylolisthesis group and 13 of 30 (43%) in the presumed discogenic pain group. Adjusting for surgical morbidity and dropout failure, by either criteria of success, the best-case positive predictive value of discography was calculated to be 50% to 60%.Positive discography was not highly predictive in identifying bona fide isolated intradiscal lesions primarily causing chronic serious LBP illness in this first study comparing discography results to a gold standard.
View details for Web of Science ID 000239832500017
View details for PubMedID 16915099
To determine whether minimally invasive lumbar spinal fusion results in less paraspinal muscle damage than conventional open posterior fusion.The maximum intramuscular pressure (IMP) generated by a minimally invasive and standard open retractor was compared in cadavers using an ultra-miniature pressure transducer. In a second clinical study, eight patients with either minimally invasive or open posterolateral lumbar spinal fusion underwent magnetic resonance imaging (MRI) scanning approximately 6 months post surgery. MRI was used to estimate edema and atrophy within multifidus, with T2 mapping and diffusion-weighted imaging allowing quantification of differences between the two surgical techniques.IMP measured with the minimally invasive retractor was 1.4 versus 4.7 kPa with the open retractor (P < 0.001). The minimally invasive retractor produced a transient maximal IMP only on initial expansion. Maximum IMP was constant throughout open retractor deployment. Striking visual differences in muscle edema were seen between open and minimally invasive groups on MRI. The mean T2 relaxation time at the level of fusion was 47 milliseconds in the minimally invasive and 90 milliseconds in the open group (P = 0.013). The mean apparent diffusion coefficient was 1357 x 10(-6) mm/s and 1626 x 10(-6) mm(2)/s (P = 0.0184), respectively.The peak IMP generated by the minimally invasive retractor was significantly less than with the open retractor. Postoperatively, less muscle edema was demonstrated after the minimally invasive lumbar spinal fusion, with lower mean T2 and apparent diffusion coefficient measurements supporting the hypothesis that less damage occurs using a minimally invasive approach.
View details for Web of Science ID 000237437600001
View details for PubMedID 16760779
Prospective observational study with historical control. The prospective study population consisted of 30 patients undergoing a posterior lumbar subtotal discectomy for lumbar disc herniation. This group was compared to a historical cohort of 46 patients treated with limited discectomy alone.To compare clinical outcomes after limited versus subtotal discectomy for lumbar disc herniations.Large posterior anular defects found at posterior discectomy have been associated with more frequent reherniation when treated with limited discectomy (i.e., removing only extruded or loose intervertebral fragments). A trial of more aggressive discectomy (subtotal) was undertaken to determine if the rate of reherniation could be decreased with this technique.A total of 30 patients undergoing a posterior lumbar discectomy for lumbar disc herniation were treated with an aggressive (subtotal) resection of intervertebral disc material after removal of the extruded or protruded fragments. This group was compared against a historical cohort of 46 patients treated with limited discectomy alone. Reherniation rates and clinical outcomes were determined by independent evaluation at 6, 12, and 24 months after surgery.The reherniation rate in the limited discectomy group was 18% versus 9% in the subtotal discectomy group at follow-up (P = 0.1). However, the back pain (visual analog scale) (P = 0.02) and Oswestry scores (P = 0.06) were worse in the subtotal discectomy group at 12-month follow-up. Time to return to work was longer, and pain medication usage was higher in the subtotal discectomy group at 12-month follow-up. Despite a trend toward a higher reherniation rate, the patient satisfaction at 2-year follow-up was higher in the limited discectomy group.The more aggressive removal of remaining intervertebral disc material may decrease the risk of reherniation, but the overall outcome was less satisfactory, especially during the first year after surgery.
View details for Web of Science ID 000236000100008
View details for PubMedID 16540869
Retrospective data review of positive disc injections at low pressures among subjects without chronic low back pain (LBP) illness compared to patients with chronic LBP undergoing Discography.To test the hypothesis that false-positive injections during Discography can effectively be eliminated by defining the positive injection criteria to include only those discs in which pain is produced with low injection pressure injections.The use of lumbar Discography as a diagnostic tool remains controversial. Studies have shown that disc injections among subjects asymptomatic of clinical LBP will produce painful injections in a significant proportion of subjects, rendering the interpretation of positive diskograms in clinical practice problematic. It has been argued that lumbar disc injections at low pressure may be clinically different from those at higher pressure and that a guideline accepting only of low-pressure injections will effectively eliminate false positives.A total of 69 volunteers with no clinically significant LBP undergoing experimental lumbar Discography were analyzed. There were 4 subgroups of this study cohort: no LBP, no chronic pain (n = 10); no LBP, chronic pain (n = 14); no LBP, previous lumbar discectomy (n = 20); and minor benign "backache" (n = 25). Pressure measurements during injection were made, and the pressure at which a significant pain response was elicited was recorded. This result was compared to the pain response and pressure profiles of 52 patients undergoing Discography for chronic LBP illness in consideration of treatment. Raters who were blinded to the subject's study group scored the studies. Diskogram morphology, pain response, and concordance, as well as magnetic resonance imaging, plain radiographs, psychometric testing (Distress and Risk Assessment Method), and compensation history were documented for each group. A low-pressure positive was defined as significant pain elicited less than 22 psi more than opening pressure.The number and percent of individuals with at least 1 low-pressure positive disc in the experimental group were 17 of 69 (25%) and in the clinical LBP group 14 of 52 (27%). The percentage of subjects with positive pain in the different experimental subgroups was: no LBP, no chronic pain 0/10 (0%); no LBP, chronic pain 5/14 (36%); no LBP, previous lumbar discectomy 5/20 (25%); and minor benign "backache" 7/25 (28%). Positive injections correlated with anular disruption, abnormal psychometric findings, and chronic pain states.The analysis shows that the rate of low-pressure painful injections in subjects without chronic LBP illness is approximately 25%, and correlates with both anatomic and psychosocial factors. In certain subgroups, this may represent an unacceptable risk of false-positive results.
View details for Web of Science ID 000235657600001
View details for PubMedID 16508542
Measurement of the monotonic and fatigue properties of osteoporotic thoracic vertebral bodies.To determine the loading values at which osteoporotic vertebral bodies are susceptible to failure.Vertebral compression fractures are the most common osteoporotic fracture. Eighty-three percent of vertebral compression fractures are caused by moderate or less trauma, and there is not a specific traumatic event in 59% of these cases. Fatigue loading can lead to premature failure, although the relationship between loading and cycles to failure is not well established.Eighteen osteoporotic thoracic vertebral bodies were tested in monotonic compression to determine the correlation between the bone mineral content and the ultimate compressive load. Seventeen osteoporotic thoracic vertebral bodies were cyclically loaded at varying percentages of the ultimate compressive load until failure to determine the relationship between loading and fatigue life.The bone mineral content was linearly correlated with ultimate compressive load. Based on our regression analysis, a 10% decrease in bone mineral content will lead to an approximate 10% decrease in ultimate compressive load. The percentage of ultimate compressive load was inversely correlated to the logarithm of cycles to failure, with specimens loaded at 60%, 70%, and 80% of ultimate compressive load lasting on average 5.6 x 10, 4.0 x 10, and 31 cycles to failure, respectively.The bone mineral content is a strong predictor of the ultimate compressive load, while the percentage of the ultimate compressive load is a strong predictor of the cycles to failure for osteoporotic thoracic vertebral bodies.
View details for Web of Science ID 000227666700009
View details for PubMedID 15770179
A range of morphologic and psychosocial variables has been suggested as risk factors for serious low back pain (LBP) illness. Although the relative contributions of structural and psychosocial variables are intensely debated, the validity of differing hypotheses has proven difficult to test because the incidence of serious disabling LBP illness is low in healthy subjects. These factors dictate the requirement for large sample sizes, extensive structural imaging and extended longitudinal study. Previous studies included either small cohorts with intensive imaging testing or large population studies that do not establish a detailed morphologic baseline.To establish, using a strict patient sample design, the relative contribution of structural and psychosocial determinants of serious LBP illness among subjects with no previous LBP disability or clinical LBP illness.A prospective, longitudinal study of subjects with high risk factors for serious LBP as determined by structural and psychosocial characteristics.One hundred subjects with known mild persistent low back pain and a 2:1 ratio of chronic (non-lumbar) pain syndrome were recruited from a study population with a predisposition to disc degenerative disease, to undergo baseline examination, testing and 5-year follow-up.Observations were made at 6-month intervals over 4 to 6 years (mean, 5.3) for the after primary outcomes measures: episodes of serious back pain (visual analogue scale [VAS] > or =6), episodes of occupational disability less than 1 week, episodes of occupational disability for 1 week, remission episodes of all back pain symptoms at least 6 months and medical visits primarily for LBP evaluation and treatment.Lumbar magnetic resonance imaging (MRI), lumbar provocative discography (in psychometrically normal subjects), physical examinations, medical and work histories and psychometric testing were performed at baseline. Imaging and psychometric testing were graded by blinded examiners. A scripted interview was conducted every 6 months during follow-up by independent research assistants who also were blinded to patient baseline data. The interview covered interval medical, occupational and accident or injury histories.Psychosocial variables strongly predicted both long- and short-term disability events, duration and health-care visits for LBP problems (p<0.0001-0.004). The likelihood of a sustained remission from the baseline persistent (subclinical) LBP appeared to be linked to occupation factors (leaving a heavy labor occupation; p=0.0001), neurophysiologic variables (chronic nonlumbar pain; p=0.0002) and psychometric profiles at baseline (DRAM and FABQ-PA; p=0.003-0.002). Of the structural findings measured only moderate or severe Modic changes of the vertebral end plate were weakly associated with an adverse outcome. A positive provocative discogram at baseline did not predict any future adverse event.The development of serious LBP disability in a cohort of subjects with both structural and psychosocial risk factors was strongly predicted by baseline psychosocial variables. Structural variables on both MRI and discography testing at baseline had only weak association with back pain episodes and no association with disability or future medical care.
View details for PubMedID 15653082
A prospective controlled longitudinal study.To determine whether subjects, asymptomatic for lower back problems, who undergo experimental discography, will develop lower back problems during the medium term to the full term.Previous work has shown significant pain on discographic injection in approximately 40% of asymptomatic subjects. It has been suggested that those subjects with painful injections would soon develop lower back pain (LBP) syndromes in the near future: that is, the experimental discography was detecting an imminent "pain generator" before clinically symptomatic. METHODS.: Fifty subjects without low back pain were recruited for clinical and psychometric testing, MRI scanning, and experimental lumbar discography to determine the rate of painful lumbar disc injections in select subjects without LBP history. After determining which subjects had painful injections, all subjects completing the discography protocol were prospectively followed at yearly intervals to determine the occurrence of LBP and LBP disability over time. Statistical methods were then used to determine the correlation, if any, between the asymptomatic subjects' clinical, MRI, and discography findings, and the subsequent LBP measures. Controls, not participating in the lumbar discography study, were also followed. Controls were matched for clinical features, sex, age, and occupational/recreational exposure. Follow-up examinations were performed at yearly intervals by blinded researchers using a scripted interview and completing standard questionnaires.A total of 46 of 50 completed the discogram, and all 46 subjects completed the final 4-year follow-up examination. There was a low incidence of LBP episodes in the experimental groups and control. A painful disc injection, independent of psychological profile, did not predict LBP or any other functional outcome measure at follow-up on multivariate analysis. The presence of an anular fissure seen on discography was weakly associated with the cumulative incidence of LBP episodes after discography (P = 0.08). The presence of high intensity zone on MRI in any disc was also weakly associated with the development of LBP episodes (P = 0.09). Psychometric profiles at the start of the study strongly and independently predicted future back pain (P = 0.01), medication usage (P = 0.002), and work loss (P = 0.01) over the 4-year study. Compared with controls not having undergone discography, there was no significant difference in back pain, function, work loss, doctors visits for back pain, or medication intake in any group. A subset in the injection group with somatization disorder had a higher LBP visual analog score compared with somatization disorder controls at 1 year,but this was not significant at 4 years after testing.Painful disc injections are poor independent predictors of subsequent LBP episodes in subjects initially without active lower back complaints. Anular disruption is a weak predictor of future LBP problems. Psychological distress and preexisting chronic pain processes are stronger predictors of LBP outcomes.
View details for Web of Science ID 000221519900011
View details for PubMedID 15131439
Whether discographic injections would be positive in subjects with benign persistent "backache" who are not seeking treatment is unknown. This information is important, because benign backache undoubtedly co-exists in patients with chronic low back pain (CLBP) illness that is not discogenicin origin. If these subjects had a high rate of positive discography, the high background incidence of common backache would allow many positive tests in patients in whom discogenic processes were unrelated to their severe CLBP illness. Conversely, if subjects with benign low back pain rarely if ever had significant concordant pain reproduction on disc injections, the basic tenet of discographic diagnosis would be strengthened.To compare, using a strict experimental design, the relative pain and concordancy response to provocative discography in subjects with clinically insignificant "backache" and clinical subjects with CLBP illness considering surgical treatment.Comparison of experimental disc injections in subjects with persistent mild backache and those with chronic low back pain (CLBP) illness.Twenty-five subjects with mild persistent low back pain (LBP) were recruited for an experimental discography study. Subjects were recruited from a clinical study of patients having had cervical spine surgery. Inclusion criteria required that subjects not be receiving or seeking medical treatment for LBP, be taking no medications for backache, have no activity restrictions because of LBP, and have normal psychometric scores. To more closely approximate the pain behavior in CLBP illness, 50% (12) of the "backache" group were recruited with a chronic painful condition (neck/shoulder) unrelated to the low back. CLBP subjects, patients coming to discography for consideration of surgical treatment, were used as control subjects.Results of discography were determined using the criteria of Walsh et al.: pain response of 3 or greater, two or more pain behaviors, a negative "control" discographic injection, and a similar or exact concordancy rating.Discography was performed on experimental subjects and control patients. Experienced raters, who were blinded to control versus experimental status of the subjects, scored the magnetic resonance image, discogram, psychometric tests and discography videotapes of the subjects' pain behavior.Thirteen of 25 volunteer subjects had pain rated as "bad" or worse with disc injection. There were 12 painful and fully concordant disc injections in 9 of these 25 "backache" subjects (36%). These injections met all the Walsh et al. criteria for a positive diagnosis of discogenic pain. All positive discs had annular disruption to or through the outer annulus. Of the 9 subjects with positive discograms, 3 had no chronic pain states and 6 did. All subjects with positive injections had negative control discs. In comparison, in 52 subjects with CLBP illness 38 (73%) had at least one positive disc injection.In a group of volunteer subjects with persistent "backache," 36% were found to have significant pain on disc injection, which is reported to be concordant with their usual pain. The presence of positive concordant pain responses and negative control discs in 33% of subjects without CLBP illness seriously challenges the specificity of provocative discography in identifying a clinically relevant spinal pathology.
View details for PubMedID 14588285
Discography is used today as the basis of the diagnosis of discogenic back and neck pain. As such, it plays a pivotal role in the formulation of treatment plans for patients complaining of chronic axial spine pain.A brief history of discography is described here, followed by a discussion of the current uses of discography, the technique involved, and recent studies questioning its validity.A selective review of discography articles from peer-reviewed literature from 1967 to 2000 is provided. We included articles analyzing the validity of discography as well as those concerning its proper use, technique, and complications.Articles relevant to the subject of discography were systematically reviewed for recommendations regarding technique, the interpretation of results, and conclusions regarding its validity.The specificity of discography is dramatically affected by the characteristics of the patient examined. In a patient with chronic pain states and psychiatric risk factors, the specificity was determined to be at most 20%. In healthy patients with no chronic pain states and a normal psychiatric profile, the specificity was found to be at most 90%. The ability of a patient to determine reliably the concordance of pain provoked during discography is poor. We could find no data addressing the sensitivity of the study.Clinicians who use discography to determine treatment pathways for their patients need to critically examine the validity of the test. Recent studies examining the specificity of discography have led us to proceed much more cautiously in interpreting the results of discography.
View details for PubMedID 14588317
The longitudinal epiphyseal bracket is a rare ossification defect of tubular bones in the hand and foot. This deformity contains an abnormal secondary ossification center, which may lead to progressive shortening and angular deformity of involved bones. This article describes the results from early treatment of this deformity before the secondary ossification center ossifies. Four patients with seven involved bones (5 metatarsals and 2 phalanges) were treated with surgical excision of the longitudinal epiphyseal brackets, without corrective osteotomy. The average age at surgery was 16 months (range, 6-20 months), and the average follow-up period was 55 months (range, 31-80 months). All five metatarsal patients demonstrated progressive improvement in the deformity. Of the two phalanx patients, one improved and the other did not. Early treatment of the longitudinal epiphyseal bracket before ossification of the secondary center with excision is effective in correcting this deformity. Long-term follow-up assessment until skeletal maturity is necessary to assess the final results of surgery because corrective osteotomy may be necessary for patients who do not have adequate correction.
View details for Web of Science ID 000168388000019
View details for PubMedID 11371821