Evid Based Spine Care J
· 2012 Feb · PMID 23236315
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STUDY DESIGN: Systematic review. CLINICAL QUESTION: Does single-level unconstrained, semiconstrained, or fully constrained cervical artificial disc replacement (C-ADR) improve health outcomes compared with single-level...STUDY DESIGN: Systematic review. CLINICAL QUESTION: Does single-level unconstrained, semiconstrained, or fully constrained cervical artificial disc replacement (C-ADR) improve health outcomes compared with single-level anterior cervical discectomy and fusion (ACDF) in the long-term? METHODS: A systematic review was undertaken for articles published up to October 2011. Electronic databases and reference lists of key articles were searched to identify US Food and Drug Administration (FDA) studies reporting long-term (≥ 48 months) follow-up results of C-ADR compared with ACDF. Non-FDA trials and FDA trials reporting outcomes at short-term or mid-term follow-up periods were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. RESULTS: Two FDA trials reporting outcomes following C-ADR (Bryan disc, Prestige disc) versus ACDF at follow-up periods of 48 months and 60 months were found (follow-up rates are 68.7% [318/463] and 50.1% [271/541], respectively). Patients in the C-ADR group showed a higher rate of overall success, greater improvements in Neck Disability Index, neck and arm pain scores, and SF-36 PhysicalComponent Scores at long-term follow-up compared with those in the ACDF group. The rate of adjacent segment disease was less in the C-ADR group versus the ACDF group at 60 months (2.9% vs 4.9%). Normal segmental motion was maintained in the C-ADR group. Furthermore, rates of revision and supplemental fixation surgical procedures were lower in the arthroplasty group. CONCLUSIONS: C-ADR is a viable treatment option for cervical herniated disc/spondylosis with radiculopathy resulting in improved clinical outcomes, maintenance of normal segmental motion, and low rates of subsequent surgical procedures at 4 to 5 years follow-up. More studies with long-term follow-up are warranted.
Evid Based Spine Care J
· 2012 Feb · PMID 23236314
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STUDY DESIGN: Cross-sectional survey. OBJECTIVES: To obtain information from the global community regarding cervical artificial disc replacement (C-ADR) use and trends before and after US Food and Drug Administration (...STUDY DESIGN: Cross-sectional survey. OBJECTIVES: To obtain information from the global community regarding cervical artificial disc replacement (C-ADR) use and trends before and after US Food and Drug Administration (FDA) approval of devices in 2007 and summarize available information on utilization and government approval for devices. METHODS: Data on utilization and approval were sought from PubMed, Google, FDA, and manufacturers' websites. The 6195 members of AOSpine International were invited to participate in a survey to assess global C-ADR use and trends. RESULTS: Publically available data on utilization, trends, and approval outside of the US and Europe is limited. No studies of utilization were found. Of 1479 professionals responding to the survey, 50% had C-ADR specific training and reported ever performing C-ADR. Most respondents believed that C-ADR was safe and effective, but approximately one quarter responded that they did not know. Of those who had done C-ADR, 49% reported performing ≥ 1 before December compared with 92% after January 2008 and 51.3% indicated that all their C-ADRs were placed in a single level; 27% reported ≥ 1 failures that required revision. The majority foresee that C-ADR use will increase in the next 5 years. Most respondents believed that the best indication is radiculopathy from soft-disc pathology rather than myelopathy or disorders arising from spondylotic (hard-disc) pathology. CONCLUSION: More C-ADR has been performed after January 2008. Most respondents expect the number to increase. There may be differences in failure rates when performed inside or outside of a sponsored research trial.
Evid Based Spine Care J
· 2012 Feb · PMID 23236313
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STUDY DESIGN: Comparative effectiveness review. STUDY RATIONALE: The ability of a patient to return to work and the speed with which this occurs are important outcome metrics for the assessment of patients undergoing sp...STUDY DESIGN: Comparative effectiveness review. STUDY RATIONALE: The ability of a patient to return to work and the speed with which this occurs are important outcome metrics for the assessment of patients undergoing spinal surgery.Clinical questions: In patients with degenerative disease of the cervical spine, does cervical artificial disc replacement (C-ADR) lead to better work-related outcomes than fusion? Does return to work after surgery differ based on gender, age, smoking, litigation status, workers' compensation status, or other sociodemographic factors? METHODS: A systematic search and review of the English-language literature was undertaken to identify studies published through October 2, 2011. PubMed, Cochrane, National Guideline Clearinghouse Databases, and bibliographies of key articles were searched. Two individuals independently reviewed articles based on inclusion and exclusion criteria, which were set a priori. Each article was evaluated using a predefined quality-rating scheme. RESULTS: For follow-up periods of more than 6 months, there was no significant difference in work status between disc replacement and fusion patients; however, C-ADR patients began working sooner after surgery. Statistical significance for earlier return was not reached in all studies. CONCLUSIONS: Most patients undergoing cervical decompression and fusion or C-ADR return to work. The rates are equivalent at 6 months but patients treated with C-ADR resumed work sooner.
Evid Based Spine Care J
· 2012 Feb · PMID 23236312
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STUDY DESIGN: Systematic review. CLINICAL QUESTION: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) i...STUDY DESIGN: Systematic review. CLINICAL QUESTION: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease? METHODS: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48-60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded. RESULTS: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%-2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups. CONCLUSION: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled.
Lehman R, Bevevino AJ, Brewer DD
… +2 more, Skelly AC, Anderson PA
Evid Based Spine Care J
· 2012 Feb · PMID 23236311
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STUDY DESIGN: Systematic review.Clinical questions: (1) What evidence is available from studies of cervical total disc arthroplasty (C-ADR) failure and retrieval regarding durability, wear, and reasons for failure of C-...STUDY DESIGN: Systematic review.Clinical questions: (1) What evidence is available from studies of cervical total disc arthroplasty (C-ADR) failure and retrieval regarding durability, wear, and reasons for failure of C-ADR? (2) What evidence is available from experimental models regarding the durability of C-ADR beyond 5 years? METHODS: We searched electronic databases to identify published reports of explanted cervical artificial discs and biomechanical simulations of disc wear. RESULTS: Nine articles were identified describing 17 devices explanted from human patients and four articles describing 23 devices explanted from non-human subjects. Wear properties were not consistently reported across studies, so summaries for specific variables are based on few cases. No device had been implanted longer than 4 years. In both human and non-human subjects, devices showed evidence of metallic and polymeric (for discs with polymer components) debris. Inflammatory cells were frequently present in surrounding soft tissues. Signs of infection were uncommon.Four patients had reactions interpreted as hypersensitivity to metal. We identified three articles on biomechanical wear simulations. Devices were tested between 10 and 20 million cycles in axial loading, flexion/extension, and lateral bending. No device failures were reported. One study suggests such simulations may represent 50 or more years of wear in actual patients. CONCLUSION: Cervical disc implants consistently produced polymeric and metallic debris, which was typically accompanied by inflammation. Hypersensitivity to metal may increase risk for device failure. Biomechanical simulations indicate that cervical disc implants may be durable beyond the currently reported length of clinical follow-up.
Kepler CK, Brodt ED, Dettori JR
… +1 more, Albert TJ
Evid Based Spine Care J
· 2012 Feb · PMID 23236310
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STUDY DESIGN: Systematic review.Clinical questions: What is the effectiveness of multilevel cervical artificial disc replacement (C-ADR) compared with multilevel fusion with respect to pain and functional outcomes, and...STUDY DESIGN: Systematic review.Clinical questions: What is the effectiveness of multilevel cervical artificial disc replacement (C-ADR) compared with multilevel fusion with respect to pain and functional outcomes, and are the two procedures comparable in terms of safety? What is the effectiveness of multilevel C-ADR compared with single-level C-ADR with respect to pain and functional outcomes, and are the two procedures comparable in terms of safety? METHODS: A systematic review was undertaken for articles published up to October 2011. Electronic databases and reference lists of key articles were searched to identify studies comparing multilevel C-ADR with multilevel anterior cervical discectomy and fusion (ACDF) or comparing multilevel C-ADR with single-level C-ADR. Studies which compared these procedures in the lumbar or thoracic spine or that reported alignment outcomes only were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. RESULTS: Two studies compared multilevel C-ADR with multilevel ACDF. While both reported improved Neck Disability Index (NDI) and Short-Form 36 (SF-36) scores after C-ADR compared with ACDF, only one study reported statistically significant results. Seven studies compared single-level C-ADR with multilevel C-ADR. RESULTS were similar in terms of overall success, NDI and SF-36 scores, and patient satisfaction. There is discrepant information regarding rates of heterotopic ossification; dysphagia rate may be higher in multilevel C-ADR. CONCLUSIONS: The literature suggests that outcomes are at least similar for multilevel C-ADR and ACDF and may favor C-ADR. Future studies are necessary before firm recommendations can be made favoring one treatment strategy. Multilevel C-ADR seems to have similar results to single-level C-ADR but may have higher rates of heterotopic ossification and dysphagia.
Evid Based Spine Care J
· 2012 Feb · PMID 23236309
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STUDY DESIGN: Systematic review.Clinical questions: What are the rates and causes of subsequent surgeries? What is the long-term complication rates following cervical artificial disc replacement (C-ADR)? How do these ra...STUDY DESIGN: Systematic review.Clinical questions: What are the rates and causes of subsequent surgeries? What is the long-term complication rates following cervical artificial disc replacement (C-ADR)? How do these rates change over time? METHODS: A systematic review was undertaken for articles published up to October 2011. Electronic databases and reference lists of key articles were searched to identify comparative and non-comparative studies reporting long-term (≥ 48 months) complications of C-ADR. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. RESULTS: Two RCTs reporting outcomes following C-ADR (Bryan disc, Prestige disc) versus anterior cervical discectomy and fusion (ACDF) at follow-ups of 4 to 5 years were found; five case series reporting outcomes following C-ADR at follow-ups of 4 to 8 years were identified. Secondary surgery rates were similar or slightly lower following C-ADR compared with fusion at 4 to 5 years postoperatively. In one small subset of an RCT, rates of adjacent disc heterotopic ossification were lower in C-ADR patients than in those treated with fusion. Rates of other adverse events were similar between treatment groups. CONCLUSIONS: There is low evidence on the long-term safety outcomes following C-ADR. Additional comparative studies with follow-up of at least 4 years are needed to fully understand the long-term safety outcomes of C-ADR compared with fusion.
Chang KC, Samartzis D, Luk KD
… +2 more, Cheung KM, Wong YW
Evid Based Spine Care J
· 2012 Feb · PMID 23236307
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STUDY DESIGN: A case report. OBJECTIVE: To report a rare case of acute spinal subdural hematoma (SSH) complicating lumbar spine surgery, its characteristic presenting symptoms, diagnostic imaging, possible cause, and p...STUDY DESIGN: A case report. OBJECTIVE: To report a rare case of acute spinal subdural hematoma (SSH) complicating lumbar spine surgery, its characteristic presenting symptoms, diagnostic imaging, possible cause, and pitfall in management. METHODS: A 59-year-old woman with lumbar spinal instability and stenosis underwent laminectomy and decompression at L3-L5 with instrumentation and fusion from L3-S1. RESULTS: Immediately following surgery, the patient presented with incapacitating pain of both lower extremities from the mid-thigh downward, which was not relieved by narcotic analgesia and was disproportional to surgical trauma. Left ankle and great toes weakness was detected at postoperative day 2 and deteriorated on day 6. Magnetic resonance imaging was performed urgently and revealed a characteristic SSH with thecal sac compression at the level of L2, proximal to the laminectomy. Emergency decompression and evacuation of the hematoma was performed. The patient had partial recovery 6 weeks postoperatively. CONCLUSION: Acute SSH is a rare complication of lumbar spine surgery. This diagnosis must be considered when severe leg pain, unresolved with analgesia and disproportional to surgical trauma, with neurological deterioration occurring after lumbar spine surgery. Magnetic resonance imaging is the imaging modality of choice to assist in the differential diagnosis of an SSH. Early surgical decompression is necessary for optimal neurological recovery.
Evid Based Spine Care J
· 2012 Feb · PMID 23236306
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OBJECTIVE: The purpose of this comparison case study is to show a potential complication associated with atlantoaxial fusion, and the preoperative evaluation that could help to avoid it. BACKGROUND DATA: The use of lat...OBJECTIVE: The purpose of this comparison case study is to show a potential complication associated with atlantoaxial fusion, and the preoperative evaluation that could help to avoid it. BACKGROUND DATA: The use of lateral mass screw fixation in atlantoaxial fusion has provided surgeons the ability to create rigid fixation, with a high success rate of fusion. While the use of screws for fixation is relatively easy to adopt, the risk of causing neurological damage to the patient is ever present. Many major structures, such as the vertebral artery, carotid artery, and spinal cord, must all be considered during surgery. METHODS: A comparison of two patients who underwent the same procedure was reviewed-the first had no complications from surgery and the second underwent revision surgery because of the C1 screw impinging on the C1 nerve exiting the foramen. RESULTS: After removal of the C1 screw and converting to a cable technique, the patient made a full recovery and neurological function was restored. CONCLUSIONS: When considering C1-C2 lateral mass screw fixation for atlantoaxial fusion, the size of the foramen should be considered. If the foramen is significantly narrowed, alternate fixation should be selected.
Evid Based Spine Care J
· 2012 Feb · PMID 23236305
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STUDY DESIGN: Systematic review.Objective or clinical question: What clinical and radiological findings in patients with lumbar-herniated nucleus pulposus can serve as predictors of surgical intervention? METHODS: Arti...STUDY DESIGN: Systematic review.Objective or clinical question: What clinical and radiological findings in patients with lumbar-herniated nucleus pulposus can serve as predictors of surgical intervention? METHODS: Articles published between January 1975 and August 2011 were systematically reviewed using Pubmed, Cochrane, National Guideline Clearinghouse Databases, and bibliographies of key articles. Each article was subject to quality rating and was analyzed by two independent reviewers. RESULTS: From 123 citations, 21 underwent full-text review. Four studies met inclusion criteria. Only baseline disability as measured by the Roland Disability Index (RDI) or the Oswestry Disability Index (ODI) was consistently associated with a greater likelihood of having discectomy surgery across multiple studies. With the current literature, we were not able to find an association between surgery and several characteristics including smoking status, body mass index, neurological deficit, positive straight leg testing, and level of herniation. CONCLUSIONS: From the limited data available, it appears that individual radiographic and clinical features are not able to predict the likelihood of surgical intervention. Higher baseline disability measurements (Oswestry and Roland) did correlate, however, with surgical treatment.
Oner A, Ely CG, Hermsmeyer JT
… +1 more, Norvell DC
Evid Based Spine Care J
· 2012 Feb · PMID 23236304
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STUDY DESIGN: Systematic review. OBJECTIVE: To determine the effectiveness of using electromyography (EMG) during intraoperative pedicle screw placement in patients with thoracic deformity. METHODS: A systematic revie...STUDY DESIGN: Systematic review. OBJECTIVE: To determine the effectiveness of using electromyography (EMG) during intraoperative pedicle screw placement in patients with thoracic deformity. METHODS: A systematic review of the English-language literature was undertaken for articles published between 1970 and July 2011. For our first question, we identified all articles that were designed to evaluate the diagnostic test characteristics (ie, measures of validity such as sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV]) of EMG for thoracic deformities in adolescent and adult patients. For our second question, we attempted to identify all articles that reported complication rates (pedicle wall breach or new neurological event) after pedicle screw placement in the same population comparing patients who did and did not undergo intraoperative EMG. Articles were excluded if they did not report or give raw data to calculate at least one of the four primary diagnostic test characteristics: sensitivity, specificity, PPV, or NPV for study question one. Articles were excluded if they did not have a "no EMG" control group for study question two. Other exclusions were reviews, editorials, case reports, non-English written studies, and animal studies. We rated the overall body of evidence with respect to each key question using a modified Grades of Recommendation Assessment, Development and Evaluation (GRADE) system for diagnostic and therapeutic studies. RESULTS: The overall strength of evidence evaluating the diagnostic characteristics was low due to inconsistent findings between studies and uncertainty of the impact of false-negatives. The fairly low sensitivity may lead to a high-false negative rate. It is unclear what the impact of false-negatives would be since no neurological injuries were identified in the studies summarized. A higher specificity would suggest a fairly low false-positive rate; however, the rates could be as high as 30%. If sudden changes in treatment are required in the absence of any adverse event, this could be considered a limitation of such testing. The overall strength of evidence for evaluating the efficacy of EMG compared with no EMG was insufficient because of literature shortage on this topic. CONCLUSION: The overall strength of evidence evaluating the diagnostic characteristics was low due to inconsistent findings between studies and uncertainty of the impact of false-negatives. Given the low sensitivity and potential high rate of false-negatives, pedicle wall breaches may occur, without EMG notification. These undetected breaches may lead to loose or weak screw position which may lead to neurovascular complications during or after a translation-rotation maneuver, especially in rigid deformities. The higher sensitivity would suggest a lower rate of false-positives. We recommend considering the use of intraoperative EMG-monitoring method to help identify potential complications based upon available technology, personal experiences and preferences; however, surgeons should keep in mind that false-positive results may lead to increased surgery time and increased blood loss. The surgeon should not depend solely on EMG since it can also render false-negatives.
López WO, Vialle EN, Anillo CC
… +2 more, Guzmao M, Vialle LR
Evid Based Spine Care J
· 2012 Feb · PMID 23236303
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STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To find out (1) if magnetic resonance imaging (MRI) findings associated with positive discography in patients with lumbar discogenic pain are caused by degenerative...STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To find out (1) if magnetic resonance imaging (MRI) findings associated with positive discography in patients with lumbar discogenic pain are caused by degenerative disc disease (DDD). (2) If clinical risk factors associated with positive discography in patients with lumbar discogenic pain are caused by DDD. METHODS: Thirty-three discographies were performed in 20 consecutive patients with chronic low back pain (LBP). All examinations were performed in the lumbar spine between L3 and S1. Patient assessment consisted of a clinical and radiological examination through a protocol that contained data on the history, visual analogue scale for pain (VAS), functional questionnaire (Oswestry), and MRI findings. Discography was considered positive using the Walsh's criteria. We examined the association between MRI and clinical findings with positive discography using logistic regression. RESULTS: Fourteen discographies (42%) were positive and 19 (58%) were negative. The mean age of patients with positive discography was 40.7 years (range, 25-56 years) and negative discography 43.1 years (range, 30-55 years). Men had a positive discography rate of 43.5% and women 40%. Patients with LBP had reduced odds of a positive discography compared with those with LBP and sciatica (OR = .5; 95% CI: 0.1-2.7); however, this association was not statistically significant. Patients with more than four previous episodes of pain versus patients with one to four episodes had greater odds of a positive discography (OR = 3.8; 95% CI: 0.07-184); but this association was not statistically significant. Patients with various pathologies on MRI had greater odds of a positive discography; however, these associations were not statistically significant either. CONCLUSIONS: Patients with a chief complaint of LBP associated with sciatica, with more than four episodes of previous LBP exacerbations and the presence of a high intensity zone (HIZ) on MRI have a higher rate of positive discography. These findings are not statistically significant, probably due to a small sample size. During discography, we found the end point resistance to be more prevalent in asymptomatic discs.
du Plessis JP, Dix-Peek S, Hoffman EB
… +2 more, Wieselthaler N, Dunn RN
Evid Based Spine Care J
· 2012 Feb · PMID 23236302
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STUDY DESIGN: Retrospective diagnostic feasibility study and clinical review. OBJECTIVES: To evaluate the feasibility of making an initial atlanto-occipital dissociation (AOD) diagnosis from four radiological measureme...STUDY DESIGN: Retrospective diagnostic feasibility study and clinical review. OBJECTIVES: To evaluate the feasibility of making an initial atlanto-occipital dissociation (AOD) diagnosis from four radiological measurements of the craniocervical relationship on lateral cervical spine x-rays and to assess the AOD patients' clinical outcomes relative to their magnetic resonance imaging (MRI) findings. METHODS: The Powers ratio, Wackenheim line, basion-dens distance (BDD), and the C1/2:C2/3 interspinous ratio were measured in 58 pediatric controls and ten MRI-confirmed patients with AOD. The ability to identify the required anatomical landmarks and make the measurements was noted and sensitivity and specificity calculated. The correspondence between the clinical presentation and outcomes for patients with AOD and their MRI features was investigated. RESULTS: Clear landmarks for measuring interspinous ratio and Wackenheim line were confirmed by all x-rays. The BDD was measureable in 90% and the Powers ratio could be calculated in only possible in 59%. The interspinous ratio and BDD offered high sensitivities and specificity. Although the Wackenheim line was consistantly measured, it conferred a low sensitivity but reasonable specificity. The Powers ratio offered high specificity with low sensitivity. On MRI, all patients with AOD had apical ligament disruption, with a high rate of interspinous ligamentous injury (8/9); prevertebral swelling (7/9); retroclival hematoma (6/9); and tectorial membrane injury (4/9). The only MRI feature associated with poor outcome was that of altered cord signal. Both patients who died had cord signal changes on T1- and T2-weighted images. The third patient with cord signal change was limited to T2 changes with a normal T1. He had a C5-L3 sensory deficit that resolved. The degree of tectorial membrane injury did not appear to influence outcome. CONCLUSIONS: The BDD and interspinous ratio offer the best measures for initial x-ray diagnosis of AOD. This will alert the surgeon to the need for MRI. These patients often have a reduced level of consciousness, thus making clinical evaluation difficult. The MRI findings, although apparently indicative of severe abnormality, did not actually correspond to outcomes except for the presence of T1 cord signal changes that matched with severe neurological impairment and subsequent death.
Evid Based Spine Care J
· 2012 Feb · PMID 23236301
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STUDY DESIGN: Retrospective case-series of prospective routinely collected Short Form 36v2 (SF-36v2) data in an outpatient spine clinic. OBJECTIVE: To determine if there is value in routine administration of outcome qu...STUDY DESIGN: Retrospective case-series of prospective routinely collected Short Form 36v2 (SF-36v2) data in an outpatient spine clinic. OBJECTIVE: To determine if there is value in routine administration of outcome questionnaires for the patient and/or clinician without a targeted population or monitoring of follow-up. METHOD: Retrospective review of Health Outcomes Scoring database. RESULTS: During an 18-month period 1,863 patients completed 3,124 SF-36v2 questionnaires. The extent of diagnoses and the uneven timing of follow-ups of the completed questionnaires render this data useless both to the patient and for aggregate analysis. CONCLUSION: There is no value in routine administration of outcome questionnaires to patient care or clinical research.Final class of evidence-prognosisSTUDY DESIGN RCT Cohort Case control Case series•METHODs Patients at similar point in course of treatment F/U ≥ 85% Similarity of treatment protocols for patient groups• Patients followed up long enough for outcomes to occur• Control for extraneous risk factorsNAOverall class of evidenceIVThe definiton of the different classes of evidence is available on page 63.