Lumbar Intervertebral Kinematics During an Unstable Sitting Task and Its Association With Standing-Induced Low Back Pain.

People developing transient low back pain during standing have altered control of their spine and hips during standing tasks, but the transfer of these responses to other tasks has not been assessed. This study used video fluoroscopy to assess lumbar spine intervertebral kinematics of people who do and do not develop standing-induced low back pain during a seated chair-tilting task. A total of 9 females and 8 males were categorized as pain developers (5 females and 3 males) or nonpain developers (4 females and 5 males) using a 2-hour standing exposure; pain developers reported transient low back pain and nonpain developers did not. Participants were imaged with sagittal plane fluoroscopy at 25 Hz while cyclically tilting their pelvises anteriorly and posteriorly on an unstable chair. Intervertebral angles, relative contributions, and anterior-posterior translations were measured for the L3/L4, L4/L5, and L5/S1 joints and compared between sexes, pain groups, joints, and tilting directions. Female pain developers experienced more extension in their L5/S1 joints in both tilting directions compared with female nonpain developers, a finding not present in males. The specificity in intervertebral kinematics to sex-pain group combinations suggests that these subgroups of pain developers and nonpain developers may implement different control strategies.

Diagnosis of spine pseudoarthrosis based on the biomechanical properties of bone.

BACKGROUND CONTEXT: Failure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis. PURPOSE: Develop and test a biomechanically based approach to the diagnosis of pseudoarthrosis. STUDY DESIGN: Literature review, development of theory, re-analysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion. METHODS: Fully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients. RESULTS: The estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2 degrees, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases. CONCLUSIONS: We propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery. CLINICAL SIGNIFICANCE: In a symptomatic postspine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis.

Allogeneic mesenchymal precursor cells treatment for chronic low back pain associated with degenerative disc disease: a prospective randomized, placebo-controlled 36-month study of safety and efficacy.

BACKGROUND CONTEXT PURPOSE: Evaluate the safety and efficacy of a single intradiscal injection of STRO-3+ adult allogeneic mesenchymal precursor cells (MPCs) combined with hyaluronic acid (HA) in subjects with chronic low back pain (CLBP) associated with degenerative disc disease (DDD) through 36-month follow-up. STUDY DESIGN/SETTING: A multicenter, randomized, controlled study conducted at 13 clinical sites (12 in the United States and 1 in Australia). SUBJECT SAMPLE: A total of 100 subjects with chronic low back pain associated with moderate DDD (modified Pfirrmann score of 3-6) at one level from L1 to S1 for at least 6 months and failing 3 months of conservative treatment, including physical therapy were randomized in a 3:3:2:2 ratio to receive 6 million MPCs with HA, 18 million MPCs with HA, HA vehicle control, or saline control (placebo) treatment. OUTCOME MEASURES: Subjects were clinically and radiographically evaluated at 1, 3, 6, 12, 24, and 36 months postinjection. Subject-reported outcomes including adverse events, LBP on a Visual Analog Scale (VAS), Oswestry Disability Index (ODI), SF-36 and Work Productivity and Activity Index were collected. METHODS: Clinical and radiographic measures were collected at each visit. All randomized subjects were included in the safety assessments and analyzed based on the treatment received. Safety assessments included assessments of AEs, physical and radiographic examinations and laboratory testing. Efficacy assessments evaluated changes in VAS, ODI, and modified Pfirrmann (MP) scores between all active and control groups, respectively. Assessments included least squares mean (Mean), LS mean change from baseline (Mean Change) and responder analyses in order to assess the clinical significance of observed changes from baseline. The population for efficacy assessments was adjusted for the confounding effects of post-treatment interventions (PTIs). This study was conducted under an FDA Investigational New Drug application sponsored and funded by Mesoblast. RESULTS: There were significant differences between the control and MPC groups for improvement in VAS and ODI. The PTI-corrected VAS and ODI Means and Mean Change analyses; the proportion of subjects with VAS ≥30% and ≥50% improvement from baseline; absolute VAS score ≤20; and ODI reduction ≥10 and ≥15 points from baseline showed MPC therapy superior to controls at various time points through 36 months. Additionally, the proportion of subjects achieving the minimally important change and clinically significant change composite endpoints for the MPC groups was also superior compared with controls at various time points from baseline to 36 months. There were no significant differences in change in MP score from baseline across the groups. There were also no statistically significant differences in change in modified MP score at the level above or below the level treated between study arms. Both the procedure and treatment were well tolerated and there were no clinical symptoms of immune reaction to allogeneic MPCs. There was a low rate of Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events, and the rates of these events in the MPC groups were not significantly different from the control groups. One TEAE of severe back pain was possibly related to study agent and one TEAE of implantation site infection was considered to be related to the study procedure. CONCLUSIONS: Results provide evidence that intradiscal injection of MPCs could be a safe, effective, durable, and minimally invasive therapy for subjects who have CLBP associated with moderate DDD.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of low back pain.

BACKGROUND CONTEXT: The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016. PURPOSE: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. STUDY DESIGN: This is a guideline summary review. METHODS: This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors. RESULTS: Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. CONCLUSIONS: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx.

Neurologic impairment from ectopic bone in the lumbar canal: a potential complication of off-label PLIF/TLIF use of bone morphogenetic protein-2 (BMP-2).

BACKGROUND CONTEXT: Bone morphogenetic protein-2 (BMP-2) (Infuse) has been approved for use in anterior lumbar fusion in conjunction with an LT cage. However, off-label use is seen with anterior cervical fusion, posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF). The Federal Food and Drug Administration trial of BMP-2 in a PLIF application was halted because of a high incidence of ectopic bone forming in the neural canal (75%). The authors did not find a correlation between ectopic bone and increased leg pain. They concluded that the ectopic bone was a radiographic phenomenon and not associated with clinical findings. Complications using BMP in the cervical spine have been reported. Heretofore, there has not been a similar warning voiced for use of BMP in a lumbar PLIF or TLIF. PURPOSE: The purpose was to report five cases of ectopic bone in the canal associated with PLIF/TLIF off-label use of BMP-2 potentially contributing to abnormal neurologic findings. STUDY DESIGN/SETTING: This is an observational cohort study of patients referred to a tertiary care private medical center. METHODS: This was a retrospective chart review of patients referred to a tertiary spine institute with complications after surgery where BMP-2 had been used in an off-label PLIF or TLIF application. Patient demographics, operating room (OR) notes from the index BMP surgery, imaging studies, and current clinical status were reviewed. RESULTS: Five cases of ectopic bone in the spinal canal with potential neurologic compromise were identified. CONCLUSIONS: It does appear that ectopic bone in the spinal canal associated with BMP-2 use in PLIF or TLIF may contribute to symptomatic neurologic findings in rare cases. Revision surgeries are difficult. This article challenges a previous publication, which concluded that the high incidence of ectopic bone was of no clinical significance. Isolating BMP anteriorly in the disc space using layered barriers of bone graft between the BMP and the annular defect may reduce the incidence of ectopic bone in the spinal canal. Surgeons need to weigh the benefits versus risks of any technology used off label when making treatment decisions with their patients.

Degenerative lumbar spinal stenosis: an evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spinal stenosis.

BACKGROUND CONTEXT: The objective of the North American Spine Society (NASS) evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spinal stenosis (DLSS) is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of DLSS. The guideline is intended to reflect contemporary treatment concepts for symptomatic DLSS as reflected in the highest quality clinical literature available on this subject as of April 2006. The goals of the guideline recommendations are to assist in delivering optimum, efficacious treatment, and functional recovery from this spinal disorder. PURPOSE: To provide an evidence-based tool that assists practitioners in improving the quality and efficiency of care delivered to patients with DLSS. STUDY DESIGN/SETTING: Evidence-based clinical guideline. METHODS: This report is from the Spinal Stenosis Work Group of the NASS Clinical Guidelines Committee. The work group comprised medical, diagnostic, interventional, and surgical spinal care specialists, all of whom were trained in the principles of evidence-based analysis. In the development of this guideline, the work group arrived at a consensus definition of a working diagnosis of lumbar spinal stenosis by use of a modification of the nominal group technique. Each member of the group formatted a series of clinical questions to be addressed by the group and the final list of questions agreed on by the group is the subject of this report. A literature search addressing each question and using a specific literature search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology), and four additional, evidence-based, databases. The relevant literature to answer each clinical question was then independently rated by at least two reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Any discrepancies in evidence levels among the initial raters were resolved by at least two additional members' review of the reference and independent rating. Final grades of recommendation for the answer to each clinical question were arrived at in face-to-face meetings among members of the work group using the NASS-adopted standardized grades of recommendation. When Levels I to IV evidence was insufficient to support a recommendation to answer a specific clinical question, expert consensus was arrived at by the work group through the modified nominal group technique and is clearly identified as such in the guideline. RESULTS: Eighteen clinical questions were asked, addressing issues of prognosis, diagnosis, and treatment of DLSS. The answers to these 18 clinical questions are summarized in this document along with their respective levels of evidence and grades of recommendation in support of these answers. CONCLUSIONS: A clinical guideline for DLSS has been created using the techniques of evidence-based medicine and using the best available evidence as a tool to aid both practitioners and patients involved with the care of this disease. The entire guideline document including the evidentiary tables, suggestions for future research, and all references is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.

Incidence of contraindications to total disc arthroplasty: a retrospective review of 100 consecutive fusion patients with a specific analysis of facet arthrosis.

BACKGROUND CONTEXT: The role of total disc arthroplasty (TDA) in the treatment of spinal pathology is unclear. TDA has been touted as an alternative to fusion. However, not all back pain is purely discogenic in origin. Contraindications to TDA exist. At Spine Week in Porto, Portugal, Cammisa's group from the Hospital for Special Surgery in New York presented a series of 56 fusions where 100% of patients had one or more of 10 contraindications to TDA. En face, this appears to be an extremely large number. PURPOSE: The purpose of the study was to repeat the Hospital for Special Surgery study in another cohort of fusion patients. STUDY DESIGN/SETTING: This study was an independent, retrospective record review of 100 consecutive lumbar spinal fusions performed at a tertiary care private medical center. PATIENT SAMPLE: All adult patients having primary1-3 level lumbar spinal fusions from January 2003 to May 2004 were assessed. OUTCOME MEASURES: Physiologic measures included imaging, range of motion, and response to facet blocks. METHODS: A retrospective chart review was performed of 100 consecutive patients having primary 1-3 level lumbar fusion by all five active staff spinal surgeons (3 orthopedic and 2 neurosurgeons). The review was performed independently by the doctorate level physiotherapist who serves as the medical center's research coordinator, reporting to the chairman of the Hospital institutional review board. The same 10 contraindications from Cammisa's study were noted. Additional facet arthrosis data were collected, including mention on imaging reports or operating room notes. Clinical notes were reviewed for documentation of range of lumbar motion (ROM) and whether there was restricted or painful extension ROM. Note was made if patients had facet blocks as another clinical indicator of facet arthrosis. RESULTS: All 100 patients had at least one contraindication to TDA. The average was 3.69 (range 1-7). Only one patient had facet arthrosis as their only contraindication. Facet arthrosis was documented on imaging reports or operating room notes in 97/100. Reduced extension was present in 71/75 charts that documented ROM. Facet blocks were performed in 12/100 and gave greater than 50% relief in nine. CONCLUSIONS: Both our study and Cammisa's indicate that all lumbar fusion patients in our two institutions have at least one contraindication to TDA. The average fusion patient does not appear to have isolated discogenic pain. A large proportion of the patients appeared to have facet arthritis. The point where facet arthrosis definitely constitutes a contradiction to TDA will require analysis during long-term arthroplasty follow-up studies. Suitable patients for TDA may not represent a significant cohort presently undergoing lumbar fusion.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of adult isthmic spondylolisthesis.

BACKGROUND CONTEXT: The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adult Isthmic Spondylolisthesis features evidence-based recommendations for diagnosing and treating adult patients with isthmic spondylolisthesis. The guideline is intended to reflect contemporary treatment concepts for symptomatic isthmic spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of June 2013. NASS' guideline on this topic is the only guideline on adult isthmic spondylolisthesis accepted in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse. PURPOSE: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with isthmic spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. STUDY DESIGN: This is a guideline summary review. METHODS: This guideline is the product of the Adult Isthmic Spondylolisthesis Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questionsto address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Adult Isthmic Spondylolisthesis guideline was accepted into the National Guideline Clearinghouse and will be updated approximately every 5 years. RESULTS: Thirty-one clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. CONCLUSIONS: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with isthmic spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

Cervical total disc replacement, part I: rationale, biomechanics, and implant types.

Cervical total disc replacement (TDR) is an attractive alternate to arthrodesis for management of disc degeneration and herniation in the cervical spine. Theoretic advantages of TDR include preservation of normal motion and biomechanics in the cervical spine and reduction of adjacent-segment degeneration. Other potential advantages include faster return to normal activity and elimination of the need for bone graft and associated donor site morbidity. This article introduces the rationale and various implant types available for cervical TDR. Part 2 of this series reviews the results and complications of specific implant designs.

Adjacent segment degeneration in the lumbar spine.

BACKGROUND: A primary concern after posterior lumbar spine arthrodesis is the potential for adjacent segment degeneration cephalad or caudad to the fusion segment. There is controversy regarding the subsequent degeneration of adjacent segments, and we are aware of no long-term studies that have analyzed both cephalad and caudad degeneration following posterior arthrodesis. A retrospective investigation was performed to determine the rates of degeneration and survival of the motion segments adjacent to the site of a posterior lumbar fusion. METHODS: Two hundred and fifteen patients who had undergone posterior lumbar arthrodesis were included in this study. The study group included 126 female patients and eighty-nine male patients. The average duration of follow-up was 6.7 years. Radiographs were analyzed with regard to arthritic degeneration at the adjacent levels both preoperatively and at the time of the last follow-up visit. Disc spaces were graded on a 4-point arthritic degeneration scale. Correlation analysis was used to determine the contribution of independent variables to the rate of degeneration. Survivorship analysis was performed to describe the degeneration of the adjacent motion segments. RESULTS: Fifty-nine (27.4%) of the 215 patients had evidence of degeneration at the adjacent levels and elected to have an additional decompression (fifteen patients) or arthrodesis (forty-four patients). Kaplan-Meier analysis predicted a disease-free survival rate of 83.5% (95% confidence interval, 77.5% to 89.5%) at five years and of 63.9% (95% confidence interval, 54.0% to 73.8%) at ten years after the index operation. Although there was a trend toward progression of the arthritic grade at the adjacent disc levels, there was no significant correlation, with the numbers available, between the preoperative arthritic grade and the need for additional surgery. CONCLUSIONS: The rate of symptomatic degeneration at an adjacent segment warranting either decompression or arthrodesis was predicted to be 16.5% at five years and 36.1% at ten years. There appeared to be no correlation with the length of fusion or the preoperative arthritic degeneration of the adjacent segment.

On-the-field evaluation of an athlete with a head or neck injury.

Head and cervical spine sports-related injuries are intimately associated. The on-field evaluation and management of the athlete with these injuries is of paramount importance to stabilize the athlete and prevent further injury. Clinicians need to be aware of the differential diagnoses and consider each possibility based on the mechanism of injury. Although recognition of head and cervical spine injuries has resulted in significant reductions of catastrophic neurological injuries, especially in the cervical spine, further advances to decrease the incidence and long-term sequelae of head and neck injuries are needed. The first step is education of the athlete and the individuals involved in the care of that athlete.

An evidence-based clinical guideline for the diagnosis and treatment of lumbar disc herniation with radiculopathy.

BACKGROUND CONTEXT: The objective of the North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation with Radiculopathy is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guideline is intended to reflect contemporary treatment concepts for symptomatic lumbar disc herniation with radiculopathy as reflected in the highest quality clinical literature available on this subject as of July 2011. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder. PURPOSE: To provide an evidence-based educational tool to assist spine specialists in the diagnosis and treatment of lumbar disc herniation with radiculopathy. STUDY DESIGN: Systematic review and evidence-based clinical guideline. METHODS: This guideline is a product of the Lumbar Disc Herniation with Radiculopathy Work Group of NASS' Evidence-Based Guideline Development Committee. The work group consisted of multidisciplinary spine care specialists trained in the principles of evidence-based analysis. A literature search addressing each question and using a specific search protocol was performed on English-language references found in Medline, Embase (Drugs and Pharmacology), and four additional evidence-based databases to identify articles. The relevant literature was then independently rated using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final recommendations to answer each clinical question were developed via work group discussion, and grades were assigned to the recommendations using standardized grades of recommendation. In the absence of Level I to IV evidence, work group consensus statements have been developed using a modified nominal group technique, and these statements are clearly identified as such in the guideline. RESULTS: Twenty-nine clinical questions were formulated and addressed, and the answers are summarized in this article. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. CONCLUSIONS: The clinical guideline has been created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with symptomatic lumbar disc herniation with radiculopathy. The entire guideline document, including the evidentiary tables, suggestions for future research, and all the references, is available electronically on the NASS Web site at http://www.spine.org/Pages/PracticePolicy/ClinicalCare/ClinicalGuidlines/Default.aspx and will remain updated on a timely schedule.

Postoperative magnetic resonance imaging assessment for potential compressive effects of retained posterior longitudinal ligament after anterior cervical fusions: a cross-sectional study.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To assess using postoperative magnetic resonance imaging whether the posterior longitudinal ligament (PLL) caused residual cord compression after anterior cervical decompression and fusion (ACDF) in a series of patients in whom the PLL was retained. SUMMARY OF BACKGROUND DATA: There is a lack of data evaluating the postoperative compressive effects of the PLL in patients undergoing ACDF providing guidance as to whether to remove or retain the PLL during discectomy to facilitate adequate decompression. METHODS: Postoperative gadolinium enhanced magnetic resonance images were reviewed in a series of 33 patients who underwent ACDF for cervical radiculomyelopathy and who had persistent or recurrent postoperative symptoms. Patients with ossification of the posterior longitudinal ligament or with a herniated disc behind the PLL were excluded from this study. RESULTS: There were no cases of discernible compression by the retained PLL identified on the magnetic resonance image (P < 0.001) as assessed by 2 independent reviewers. Four patients underwent subsequent revision surgery unrelated to the PLL. CONCLUSION: We were unable to demonstrate magnetic resonance imaging evidence to suggest that the retained PLL caused compression after ACDF in this patient cohort. Therefore we suggest that removing the PLL should be considered for reasons other than concern about residual compression.

Prospective analysis of imaging prediction of pseudarthrosis after anterior cervical discectomy and fusion: computed tomography versus flexion-extension motion analysis with intraoperative correlation.

STUDY DESIGN: A prospective comparison of quantitative motion analyzed (QMA) flexion/extension radiographs versus computed tomography (CT) as an analytical predictor of cervical pseudarthrosis. Intraoperative confirmation of the fusion was performed. OBJECTIVE: To prospectively compare motion analyzed flexion/extension radiographs to CT to predict pseudarthroses. Define motion thresholds on flexion/extension radiographs to define pseudarthroses. SUMMARY OF BACKGROUND DATA: Assessment of postoperative fusion success is an important factor in assessing success after anterior cervical spine fusion. Gross intervertebral motion can be used as a measure; however, the current "gold standard" for determining fusion status is a CT to assess bridging bone. Defining the amount of intervertebral motion at the fusion site has been previously addressed and definitions have varied widely. METHODS: Data were analyzed at 47 fusion segments. Intervertebral motion at the fusion site was measured from flexion/extension radiographs taken at least 1 year after the cervical spine fusion. Motion was quantified from digitized radiographs by an independent researcher using proprietary quantitative motion analysis (QMA) software. CT scans on all patients were analyzed for fusion status by a neuroradiologist. Those patients determined to have a symptomatic pseudarthrosis were revised and intraoperative motion at the facet joints was documented. Correlation between intraoperative findings, CT and QMA was performed. RESULTS: Using greater than 4° of measured motion on flexion/extension radiographs resulted in a Spearman correlation P-value of 0.096 (95% confidence interval: -0.06 to 0.66). Using greater than 1° of motion, the Spearman correlation P < 0.0001 (95% CI: 0.54-0.90). The positive predictive value (PPV) using 4° of motion as the criterion was 100%, indicating a high specificity. The negative predictive value (NPV) was 52%, indicating a low sensitivity. Using greater than 1° of motion, the PPV was 100% and the NPV was 73%. Findings from CT showed an identical PPV and NPV to assessments made using greater than 1° of rotation. Specificity and positive predictive value were 100% for all criteria. Using a lack of bridging on CT or more than 1° of intervertebral motion during flexion/extension increased the sensitivity to 85% and the negative predictive value to 85%. CONCLUSION: A threshold level of 4° of motion is commonly used to identify a pseudarthrosis. Our prospective study suggests that this value has a high PPV, but a low specificity and would miss many of the pseudarthroses that have angular motion less than 4° (sensitivity 23%). By lowering the threshold for angular motion to 1°, the sensitivity improves to 77%. CT scan has been touted as the gold standard, and it has a high positive predictive value of 100%. However, its NPV was slightly lower than using 1° of motion on QMA analyzed flexion-extension films (73% vs. 79%). In conclusion, although CT scan has long been regarded as the gold standard for determining a pseudarthrosis in the cervical spine, the interpretation is subjective and vulnerable to both type I and type II errors. Analysis of motion using Quantitative Motion Analysis is seemingly less subjective than CT and in our prospective study was more predictive of an operatively confirmed pseudarthrosis.

An evidence-based clinical guideline for the diagnosis and treatment of cervical radiculopathy from degenerative disorders.

BACKGROUND CONTEXT: The North American Spine Society (NASS) Evidence-Based Clinical Guideline on the Diagnosis and Treatment of Cervical Radiculopathy from Degenerative Disorders provides evidence-based recommendations on key clinical questions concerning the diagnosis and treatment of cervical radiculopathy from degenerative disorders. The guideline addresses these questions based on the highest quality clinical literature available on this subject as of May 2009. The guideline's recommendations assist the practitioner in delivering optimum efficacious treatment of and functional recovery from this common disorder. PURPOSE: Provide an evidence-based educational tool to assist spine care providers in improving quality and efficiency of care delivered to patients with cervical radiculopathy from degenerative disorders. STUDY DESIGN: Systematic review and evidence-based clinical guideline. METHODS: This report is from the Cervical Radiculopathy from Degenerative Disorders Work Group of the NASS' Evidence-Based Clinical Guideline Development Committee. The work group consisted of multidisciplinary spine care specialists trained in the principles of evidence-based analysis. Each member of the group formatted a series of clinical questions to be addressed by the group. The final questions agreed on by the group are the subjects of this report. A literature search addressing each question using a specific search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology), and four additional evidence-based databases. The relevant literature was then independently rated by a minimum of three reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final recommendations to answer each clinical question were arrived at via work group discussion, and grades were assigned to the recommendations using standardized grades of recommendation. In the absence of Levels I to IV evidence, work group consensus statements have been developed using a modified nominal group technique, and these statements are clearly identified as such in the guideline. RESULTS: Eighteen clinical questions were formulated, addressing issues of natural history, diagnosis, and treatment of cervical radiculopathy from degenerative disorders. The answers are summarized in this article. The respective recommendations were graded by the strength of the supporting literature, which was stratified by levels of evidence. CONCLUSIONS: A clinical guideline for cervical radiculopathy from degenerative disorders has been created using the techniques of evidence-based medicine and best available evidence to aid both practitioners and patients involved with the care of this condition. The entire guideline document, including the evidentiary tables, suggestions for future research, and all references, is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.

An evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spondylolisthesis.

BACKGROUND CONTEXT: The objective of the North American Spine Society (NASS) evidence-based clinical guideline on the diagnosis and treatment of degenerative lumbar spondylolisthesis is to provide evidence-based recommendations on key clinical questions concerning the diagnosis and treatment of degenerative lumbar spondylolisthesis. The guideline is intended to address these questions based on the highest quality clinical literature available on this subject as of January 2007. The goal of the guideline recommendations is to assist the practitioner in delivering optimum, efficacious treatment of and functional recovery from this common disorder. PURPOSE: To provide an evidence-based, educational tool to assist spine care providers in improving the quality and efficiency of care delivered to patients with degenerative lumbar spondylolisthesis. STUDY DESIGN: Systematic review and evidence-based clinical guideline. METHODS: This report is from the Degenerative Lumbar Spondylolisthesis Work Group of the NASS Evidence-Based Clinical Guideline Development Committee. The work group was comprised of multidisciplinary spine care specialists, all of whom were trained in the principles of evidence-based analysis. Each member participated in the development of a series of clinical questions to be addressed by the group. The final questions agreed on by the group are the subject of this report. A literature search addressing each question and using a specific search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology) and four additional, evidence-based, databases. The relevant literature was then independently rated by at least three reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final grades of recommendation for the answer to each clinical question were arrived at via face-to-face meetings among members of the work group using standardized grades of recommendation. When Level I-IV evidence was insufficient to support a recommendation to answer a specific clinical question, expert consensus was arrived at by the work group through the modified nominal group technique and is clearly identified as such in the guideline. RESULTS: Nineteen clinical questions were formulated, addressing issues of prognosis, diagnosis, and treatment of degenerative lumbar spondylolisthesis. The answers to these 19 clinical questions are summarized in this document. The respective recommendations were graded by the strength of the supporting literature that was stratified by levels of evidence. CONCLUSIONS: A clinical guideline for degenerative lumbar spondylolisthesis has been created using the techniques of evidence-based medicine and using the best available evidence as a tool to aid practitioners involved with the care of this condition. The entire guideline document, including the evidentiary tables, suggestions for future research, and all references, is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.

L5-S1 segment survivorship and clinical outcome analysis after L4-L5 isolated fusion.

STUDY DESIGN: A retrospective investigation of the L5-S1 motion segment after an isolated L4-L5 posterior lumbar fusion. OBJECTIVE: To determine the survivorship of the L5-S1 segment in patients undergoing L4-L5 fusion and to identify the correlation between radiographic degeneration and clinical outcome at this level. SUMMARY OF BACKGROUND DATA: There is current controversy regarding future degeneration of the L5-S1 segment following single-segment fusion at L4-L5. There are no long-term studies that look at L5-S1 after L4-L5 fusion to assess the rate of degeneration at this adjacent segment and the functional clinical outcome of the patient. METHODS: Thirty-two consecutive patients (average age 56.4 years, range 27-77 years) having isolated L4-L5 posterior spinal fusion for instability or stenosis by a single surgeon were included in this study. There were 25 females and 7 males with an average follow-up of 7.3 years (range 2.3-12.4 years). A survivorship analysis was performed to determine the degeneration at the adjacent L5-S1 segment. Radiographs were analyzed for arthritic degeneration at that level. At the time of the L4-L5 index procedure, the L5-S1 disc spaces were graded on a 4-point scale for degeneration. Questionnaires were submitted by mail, and telephone interviews were conducted by one of the authors to determine the current level of patient function. RESULTS: Of the total 32 patients assessed, 31 (97%) had no evidence of symptomatic degeneration at L5-S1 requiring additional decompression or fusion. One patient had clinical symptoms that required a foraminotomy and laminotomy at L5-S1, but none of the patients required any further fusion. Although there was a trend of progression of the arthritic grade at L5-S1 from preoperative to postoperative examination, there was no correlation between preoperative arthritic grade versus further degeneration. The discs showed progression of degeneration from an average score of 2.28 before surgery to a score of 2.49 after surgery at the last follow-up. CONCLUSION: There appears to be no need to routinely include the L5-S1 segment when performing a posterior lumbar fusion for patients with instability or stenosis at L4-L5 if no symptoms are attributed to the lumbosacral level. At an average of 7.3 years, there was neither increased symptomatic disc degeneration nor symptoms necessitating the need for an L5-S1 fusion.