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Objective: The purpose of this study was to determine the effect of osteoporosis medications on opportunistic CT-based Hounsfield units (HU)., Methods: Spine and nonspine surgery patients were retrospectively identified who had been treated with romosozumab for 3 to 12 months, teriparatide for 3 to 12 months, teriparatide for > 12 months, denosumab for > 12 months, or alendronate for > 12 months. HU were measured in the L1-4 vertebral bodies. One-way ANOVA was used to compare the mean change in HU among the five treatment regimens., Results: In total, 318 patients (70% women) were included, with a mean age of 69 years and mean BMI of 27 kg/m2. There was a significant difference in mean HU improvement (p < 0.001) following treatment with romosozumab for 3 to 12 months (n = 32), teriparatide for 3 to 12 months (n = 30), teriparatide for > 12 months (n = 44), denosumab for > 12 months (n = 123), and alendronate for > 12 months (n = 100). Treatment with romosozumab for a mean of 10.5 months significantly increased the mean HU by 26%, from a baseline of 85 to 107 (p = 0.012). Patients treated with teriparatide for > 12 months (mean 23 months) experienced a mean HU improvement of 25%, from 106 to 132 (p = 0.039). Compared with the mean baseline HU, there was no significant difference after treatment with teriparatide for 3 to 12 months (110 to 119, p = 0.48), denosumab for > 12 months (105 to 107, p = 0.68), or alendronate for > 12 months (111 to 113, p = 0.80)., Conclusions: Patients treated with romosozumab for a mean of 10.5 months and teriparatide for a mean of 23 months experienced improved spinal bone mineral density as estimated by CT-based opportunistic HU. Given the shorter duration of effective treatment, romosozumab may be the preferred medication for optimization of osteoporotic patients in preparation for elective spine fusion surgery.

Objective: The authors sought to assess whether Hounsfield units (HU) increase following teriparatide treatment and to compare HU increases with changes in bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DEXA)., Methods: A retrospective chart review was performed from 1997 to 2018 across all campuses at our institution. The authors identified patients who had been treated with at least 6 months of teriparatide and compared HU and BMD as measured on DEXA scans before and after treatment., Results: Fifty-two patients were identified for analysis (46 women and 6 men, average age 67 years) who underwent an average of 20.9 ± 6.5 months of teriparatide therapy. The mean ± standard deviation HU increase throughout the lumbar spine (L1-4) was from 109.8 ± 53 to 133.9 ± 61 HU (+22%, 95% CI 1.2-46, p value = 0.039). Based on DEXA results, lumbar spine BMD increased from 0.85 to 0.93 g/cm2 (+9%, p value = 0.044). Lumbar spine T-scores improved from -2.4 ± 1.5 to -1.7 ± 1.5 (p value = 0.03). Average femoral neck T-scores improved from -2.5 ± 1.1 to -2.3 ± 1.0 (p value = 0.31)., Conclusions: Teriparatide treatment increased both HU and BMD on DEXA in the lumbar spine, without a change in femoral BMD. The 22% improvement in HU surpassed the 9% improvement determined with DEXA. These results support some surgeons' subjective sense that intraoperative bone quality following teriparatide treatment is better than indicated by DEXA results. To the authors' knowledge, this is the first study demonstrating an increase in HU with teriparatide treatment.

OBJECTIVE Reporting of adverse events (AEs) in spinal surgery uses inconsistent definitions and severity grading, making it difficult to compare results between studies. The Spinal Adverse Events Severity System, version 2 (SAVES-V2) aims to standardize the classification of spine surgery AEs; however, its inter- and intraobserver reliability are unknown. The objective of this study was to assess inter- and intraobserver reliability of the SAVES-V2 grading system for assessing AEs in spinal surgery. METHODS Two multinational, multicenter surgical study groups assessed surgical case vignettes (10 trauma and 12 degenerative cases) for AE occurrence by using SAVES-V2. Thirty-four members of the Spine Trauma Study Group (STSG) and 17 members of the Degenerative Spine Study Group (DSSG) participated in the first round of case vignettes. Six months later, the same case vignettes were randomly reorganized and presented in an otherwise identical manner. Inter- and intraobserver agreement on the presence, severity, number, and type of AE, as well as the impact of the AE on length of stay (LOS) were assessed using intraclass correlation (ICC), Cohen's kappa value, and the percentage of participants in agreement. RESULTS Agreement on the presence of AEs ranged from 97% to 100% in the 2 groups. Severity classification showed substantial interobserver (ICC = 0.75 for both groups) and intraobserver (ICC = 0.70 in DSSG, 0.71 in STSG) agreement. Judgments on the number of AEs showed high interobserver agreement and moderate intraobserver agreement in both groups. Both the STSG and DSSG had high intraobserver agreement on the type of AE; interobserver agreement for AE type was high in the STSG and fair in the DSSG. Agreement on impact of the AE on LOS was excellent in the DSSG and fair in the STSG. CONCLUSIONS There was good agreement on the presence, severity, and number of AEs in both trauma and degenerative cases in using the SAVES-V2. This grading system is a simple, reliable tool for identifying and capturing AEs in spinal surgery.

OBJECTIVE Beginning in 2008, the Centers for Medicare and Medicaid Service (CMS) determined that certain hospital-acquired adverse events such as surgical site infection (SSI) following spine surgery should never occur. The following year, they expanded the ruling to include deep vein thrombosis (DVT) and pulmonary embolism (PE) following total joint arthroplasty. Due to their ruling that "never events" are not the payers' responsibility, CMS insists that the costs of managing these complications be borne by hospitals and health care providers, rather than billings to health care payers for additional care required in their management. Data comparing the expected costs of such adverse events in patients undergoing spine and orthopedic surgery have not previously been reported. METHODS The California State Inpatient Database (CA-SID) from 2008 to 2009 was used for the analysis. All patients with primary procedure codes indicating anterior cervical discectomy and fusion (ACDF), posterior lumbar interbody fusion (PLIF), lumbar laminectomy (LL), total knee replacement (TKR), and total hip replacement (THR) were analyzed. Patients with diagnostic and/or treatment codes for DVT, PE, and SSI were separated from patients without these complication codes. Patients with more than 1 primary procedure code or more than 1 complication code were excluded. Median charges for treatment from primary surgery through 3 months postoperatively were calculated. RESULTS The incidence of the examined adverse events was lowest for ACDF (0.6% DVT, 0.1% PE, and 0.03% SSI) and highest for TKA (1.3% DVT, 0.3% PE, 0.6% SSI). Median inpatient charges for uncomplicated LL was $51,817, compared with $73,432 for ACDF, $143,601 for PLIF, $74,459 for THR, and $70,116 for TKR. Charges for patients with DVT ranged from $108,387 for TKR (1.5 times greater than index) to $313,536 for ACDF (4.3 times greater than index). Charges for patients with PE ranged from $127,958 for TKR (1.8 times greater than index) to $246,637 for PLIF (1.7 times greater than index). Charges for patients with SSI ranged from $168,964 for TKR (2.4 times greater than index) to $385,753 for PLIF (2.7 times greater than index). CONCLUSIONS Although incidence rates are low, adverse events of spinal procedures substantially increase the cost of care. Charges for patients experiencing DVT, PE, and SSI increased in this study by factors ranging from 1.8 to 4.3 times those for patients without such complications across 5 common spinal and orthopedic procedures. Cost projections by health care providers will need to incorporate expected costs of added care for patients experiencing such complications, assuming that the cost burden of such events continues to shift from payers to providers.

Object: Insertion of instruments or implants into the spine carries a risk for injury to neural tissue. Triggered electromyography (tEMG) is an intraoperative neuromonitoring technique that involves electrical stimulation of a tool or screw and subsequent measurement of muscle action potentials from myotomes innervated by nerve roots near the stimulated instrument. The authors of this study sought to determine the ability of tEMG to detect misplaced pedicle screws (PSs)., Methods: The authors searched the U.S. National Library of Medicine, the Web of Science Core Collection database, and the Cochrane Central Register of Controlled Trials for PS studies. A meta-analysis of these studies was performed on a per-screw basis to determine the ability of tEMG to detect misplaced PSs. Sensitivity, specificity, and receiver operating characteristic (ROC) area under the curve (AUC) were calculated overall and in subgroups., Results: Twenty-six studies were included in the systematic review. The authors analyzed 18 studies in which tEMG was used during PS placement in the meta-analysis, representing data from 2932 patients and 15,065 screws. The overall sensitivity of tEMG for detecting misplaced PSs was 0.78, and the specificity was 0.94. The overall ROC AUC was 0.96. A tEMG current threshold of 10-12 mA (ROC AUC 0.99) and a pulse duration of 300 µsec (ROC AUC 0.97) provided the most accurate testing parameters for detecting misplaced screws. Screws most accurately conducted EMG signals (ROC AUC 0.98)., Conclusions: Triggered electromyography has very high specificity but only fair sensitivity for detecting malpositioned PSs.

Object: The aim of this study is to evaluate the relationship between preoperative opioid strength and outcomes of anterior cervical decompressive surgery., Methods: A retrospective cohort of 1004 patients enrolled in 1 of 2 investigational device exemption studies comparing cervical total disc arthroplasty (TDA) and anterior cervical discectomy and fusion (ACDF) for single-level cervical disease causing radiculopathy or myelopathy was selected. At a preoperative visit, opioid use data, Neck Disability Index (NDI) scores, 36-Item Short-Form Health Survey (SF-36) scores, and numeric rating scale scores for neck and arm pain were collected. Patients were divided into strong (oxycodone/morphine/meperidine), weak (codeine/propoxyphene/hydrocodone), and opioid-naïve groups. Preoperative and postoperative (24 months) outcomes scores were compared within and between groups using the paired t-test and ANCOVA, respectively., Results: Patients were categorized as follows: 226 strong, 762 weak, and 16 opioid naïve. The strong and weak groups were similar with respect to age, sex, race, marital status, education level, Worker's Compensation status, litigation status, and alcohol use. At 24-month follow-up, no differences in change in arm or neck pain scores (arm: strong -52.3, weak -50.6, naïve -54.0, p = 0.244; neck: strong -52.7, weak -50.8, naïve -44.6, p = 0.355); NDI scores (strong -36.0, weak -33.3, naïve -32.3, p = 0.181); or SF-36 Physical Component Summary scores (strong: 14.1, weak 13.3, naïve 21.7, p = 0.317) were present. Using a 15-point improvement in NDI to determine success, the authors found no between-groups difference in success rates (strong 80.6%, weak 82.7%, naïve 73.3%, p = 0.134). No difference existed between treatment arms (TDA vs ACDF) for any outcome at any time point., Conclusions: Preoperative opioid strength did not adversely affect outcomes in this analysis. Careful patient selection can yield good results in this patient population.

Object: Iatrogenic foraminal stenosis is a well-known complication in cervical spine surgery. Machined interfacet allograft spacers can provide a large surface area, which ensures solid support, and could potentially increase foraminal space. The authors tested the hypothesis that machined interfacet allograft spacers increase cervical foraminal height and area., Methods: The C4-5, C5-6, and C6-7 facets of 4 fresh adult cadavers were exposed, and the cartilage was removed from each facet using customized rasps. Machined allograft spacers were tamped into the joints. The spines were scanned with the O-arm surgical imaging system before and after placement of the spacers. Two individuals independently measured foraminal height and area on obliquely angled sagittal images., Results: Foraminal height and area were significantly greater following placement of the machined interfacet spacers at all levels. The Pearson correlation between the 2 radiographic reviewers was very strong (r = 0.971, p = 0.0001), as was the intraclass correlation coefficient (ICC = 0.907, p = 0.0001). The average increase in foraminal height was 1.38 mm. The average increase in foraminal area was 18.4% (0.097 cm(2)) [corrected]., Conclusions: Modest distraction of the facets using machined interfacet allograft spacers can increase foraminal height and area and therefore indirectly decompress the exiting nerve roots. This technique can be useful in treating primary foraminal stenosis and also for preventing iatrogenic foraminal stenosis that may occur when the initially nonlordotic spine is placed into lordosis either with repositioning after central canal decompression or with correction using instrumentation. These grafts may be a useful adjunct to the surgical treatment of cervical spine disease.

Object: The theoretical advantage of pars interarticularis repair over spinal fusion to correct pars defects is that the treatment is a direct osteosynthesis that preserves motion at the involved functional spinal unit. Several techniques and constructs have been used to achieve greater rigidity, but these techniques may risk entry into the spinal canal, and adverse events are common. A pedicle and laminar screw construct placed entirely outside the spinal canal may offer greater stiffness and achieve higher pars defect healing rates. The purpose of this study was to biomechanically assess an intralaminar screw construct in cadaveric lumbar spines in comparison with other types of constructs typically used in pars repair and to quantify the sizes of screws that can be placed safely in both normal and spondylolytic vertebrae., Methods: The L-4 and L-5 laminae in patients with spondylolysis and in controls who underwent CT (n = 41, each group) were measured by analysis of conventional axial CT images and multiplanar reformations constructed on a Vitrea workstation to determine the feasibility of translaminar fixation with a 4.5-mm-diameter screw. Biomechanical tests for torsion and flexion-extension were performed on 8 fresh human cadaveric lumbar spines before and after modeling for bilateral spondylolytic defects. Three pars repair techniques were tested at each level and in the following sequence: pedicle screw-cable, pedicle screw-rod-hook, and pedicle screw-intralaminar screw., Results: The majority of laminae can accept 4.5 × 25-mm screws. The cable construct allowed the greatest motion and least stability across the defect in all biomechanical tests. The hook and laminar screw constructs performed similarly in all tests and exhibited no significant difference in stiffness., Conclusions: A surgically placed intralaminar screw construct may be a safe and effective alternative to current pars repair methods.

Thoracolumbar fracture-dislocations are devastating injuries. They usually require surgical reduction and stabilization. The authors present a novel technique for reducing these injuries that is predictable and reproducible.

Object: Dural tears are a frequent complication of spinal surgery and contribute to significant morbidity. Occasionally, dural tears cannot be closed primarily and dural patch grafts must be utilized. No data exist on the comparative immediate hydrostatic strength of various patch materials used alone or with a biological adhesive in a spinal dural tear model. Thus, the authors conducted this study to determine the comparative effectiveness of various patch materials used with and without biological adhesive., Methods: Twenty-four thoracic spines from calves were prepared with laminectomies and spinal cord evacuation, leaving the dura intact. Foley catheters were inflated on either side of a planned dural defect, and baseline hydrostasis was measured using a fluid column at 30, 60, and 90 cm of H(2)O. A standard dural defect (1 × 2 cm) was created, and 8 patches of each material (human fascia lata, Duragen, and Preclude) were sutured in place using 5-0 Prolene hemo-seal running sutures. Hydrostasis was again tested at the same pressures. Finally, a hydrogel sealant (Duraseal) was placed over the defect and hydrostasis was again tested. Results were analyzed with repeated measures ANOVA., Results: The leakage rate increased significantly at each pressure tested for all conditions. There was no difference in leakage among the 3 patch materials at any of the pressures or for either condition (with or without sealant). All patch materials allowed significantly greater leakage than the intact condition at all pressures. The use of sealant reduced leakage significantly at the 30 and 60 mm Hg pressures to levels similar to the intact condition. At 90 mm Hg, leakage of the sealed construct was greater than at the intact condition but significantly less than without the use of sealant., Conclusions: All 3 dural patch materials were of similar hydrostatic strength and allowed greater leakage than at the intact condition. The use of sealant reduced the amount of leakage at all pressures compared with patching alone but allowed more leakage than the intact state at a high hydrostatic pressure (90 mm Hg).

OBJECT Numerous techniques have been historically used for occipitocervical fusion with varied results. The purpose of this study was to examine outcomes of various surgical techniques used in patients with various disease states to elucidate the most efficacious method of stabilization of the occipitocervical junction. METHODS A literature search of peer-reviewed articles was performed using PubMed and CINAHL/Ovid. The key words "occipitocervical fusion," "occipitocervical fixation," "cervical instrumentation," and "occipitocervical instrumentation" were used to search for relevant articles. Thirty-four studies were identified that met the search criteria. Within these studies, 799 adult patients who underwent posterior occipitocervical fusion were analyzed for radiographic and clinical outcomes including fusion rate, time to fusion, neurological outcomes, and the rate of adverse events. RESULTS No articles stronger than Class IV were identified in the literature. Among the patients identified within the cited articles, the use of posterior screw/rod instrumentation constructs were associated with a lower rate of postoperative adverse events (33.33%) (p < 0.0001), lower rates of instrumentation failure (7.89%) (p < 0.0001), and improved neurological outcomes (81.58%) (p < 0.0001) when compared with posterior wiring/rod, screw/plate, and onlay in situ bone grafting techniques. The surgical technique associated with the highest fusion rate was posterior wiring and rods (95.9%) (p = 0.0484), which also demonstrated the shortest fusion time (p < 0.0064). Screw/rod techniques also had a high fusion rate, fusing in 93.02% of cases. When comparing outcomes of surgical techniques depending on the disease status, inflammatory diseases had the lowest rate of instrumentation failure (0%) and the highest rate of neurological improvement (90.91%) following the use of screw/rod techniques. Occipitocervical fusion performed for the treatment of tumors by using screw/rod techniques had the lowest fusion rate (57.14%) (p = 0.0089). Traumatic causes of occipitocervical instability had the highest percentage of pain improvement with the use of screw/plates (100% improvement) (p < 0.0001). CONCLUSIONS Based on the existing literature, techniques that use screw/rod constructs in occipitocervical fusion are associated with very favorable outcomes in all categories assessed for all disease processes. For patients requiring occipitocervical arthrodesis for the treatment of inflammatory diseases, screw/rod constructs are associated with the most favorable outcomes, while posterior wiring and onlay in situ bone grafting is associated with the least favorable outcomes. Occipitocervical arthrodesis performed for the diagnosis of tumor is associated with the lowest rate of successful arthrodesis using screw/rod techniques, while posterior wiring and rods have the highest rate of arthrodesis. The nonspecified disease group had the lowest rate of surgical adverse events and the highest rate of neurological improvement.

Object: The objective of this systematic review was to use evidence-based medicine to determine the efficacy of interbody graft techniques., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical interbody grafting. Abstracts were reviewed and studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Autograft bone harvested from the iliac crest, allograft bone from either cadaveric iliac crest or fibula, or titanium cages and rectangular fusion devices, with or without the use of autologous graft or substitute, have been successful in creating arthrodesis after 1- or 2-level anterior cervical discectomy with fusion (Class II). Alternatives to autograft, allograft, or titanium cages include polyetheretherketone cages and carbon fiber cages (Class III). Polyetheretherketone cages have been used successfully with or without hydroxyapatite for anterior cervical discectomy with fusion. Importantly, recombinant human bone morphogenic protein-2 carries a complication rate of up to 23-27% (especially local edema) compared with 3% for a standard approach., Conclusions: Current evidence does not support the routine use of interbody grafting for cervical arthrodesis. Multiple strategies for interbody grafting have been successful with Class II evidence supporting the use of autograft, allograft, and titanium cages.

Object: The objective of this systematic review was to use evidence-based medicine to identify the best techniques for anterior cervical nerve root decompression., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to techniques for the surgical management of cervical radiculopathy. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer-review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Both anterior cervical discectomy (ACD) and anterior cervical discectomy with fusion (ACDF) are equivalent treatment strategies for 1-level disease with regard to functional outcome (Class II). Anterior cervical discectomy with fusion may achieve a more rapid reduction of neck and arm pain compared to ACD with a reduced risk of kyphosis, although functional outcomes may be similar. Anterior cervical discectomy with fusion is not a lasting means of increasing foraminal or disc height compared to ACD. Anterior cervical plating (ACDF with instrumentation) improves arm pain (but not other clinical parameters) better than ACDF in the treatment of 2-level disease (Class II). With respect to 1-level disease, plating may reduce the risk of pseudarthrosis and graft problems (Class III) but does not necessarily improve clinical outcome alone (Class II). Cervical arthroplasty is recommended as an alternative to ACDF in selected patients for control of neck and arm pain (Class II)., Conclusions: Anterior cervical discectomy, ACDF, and arthroplasty are effective techniques for addressing surgical cervical radiculopathy.

Object: The objective of this systematic review was to use evidence-based medicine to examine the efficacy of cervical laminectomy and fusion for the treatment of cervical spondylotic myelopathy (CSM)., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical laminectomy, fusion, and CSM. Abstracts were reviewed, after which studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Class I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations which contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer-review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Cervical laminectomy with fusion (arthrodesis) improves functional outcome in patients with CSM and ossification of the posterior longitudinal ligament (OPLL). Functional improvement is similar to laminectomy or laminoplasty for patients with CSM and OPLL. In contrast to laminectomy, cervical laminectomy with fusion it is not associated with late deformity (Class III)., Conclusions: Laminectomy with fusion (arthrodesis) is an effective strategy to improve functional outcome in CSM and OPLL.

Object: The objective of this systematic review was to use evidence-based medicine to identify the indications and utility of anterior cervical nerve root decompression., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to surgical management of cervical radiculopathy. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Anterior nerve root decompression via anterior cervical discectomy (ACD) with or without fusion for radiculopathy is associated with rapid relief (3-4 months) of arm/neck pain, weakness, and/or sensory loss compared with physical therapy (PT) or cervical collar immobilization. Anterior cervical discectomy and ACD with fusion (ACDF) are associated with longer term (12 months) improvement in certain motor functions compared to PT. Other rapid gains observed after anterior decompression (diminished pain, improved sensation, and improved strength in certain muscle groups) are also maintained over the course of 12 months. However, comparable clinical improvements with PT or cervical immobilization therapy are also present in these clinical modalities (Class I). Conflicting evidence exists as to the efficacy of anterior cervical foraminotomy with reported success rates of 52-99% but recurrent symptoms as high as 30% (Class III)., Conclusions: Anterior cervical discectomy, ACDF, and anterior cervical foraminotomy may improve cervical radicular symptoms. With regard to ACD and ACDF compared to PT or cervical immobilization, more rapid relief (within 3-4 months) may be seen with ACD or ACDF with maintenance of gains over the course of 12 months (Class I). Anterior cervical foraminotomy is associated with improvement in clinical function but the quality of data are weaker (Class III), and there is a wide range of efficacy (52-99%).

In March 2006, the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and Congress of Neurological Surgeons compiled an expert group to perform an evidence-based review of the clinical literature on management of cervical degenerative spine disease. This process culminated in the formation of the Guidelines for the Surgical Management of Cervical Degenerative Disease. The purpose of the Guidelines was to address questions regarding the therapy, diagnosis, and prognosis of cervical degenerative disease using an evidence-based approach. Development of an evidence-based review and recommendations is a multitiered process. Typical guideline development consists of 5 processes: 1) collection and selection of the evidence; 2) assessment of the quality and strength of the evidence; 3) analysis of the evidentiary data; 4) formulation of recommendations; and 5) guideline validation. This manuscript details the methodology in compiling the Guidelines for the Surgical Management of Cervical Degenerative Disease.

Object: The objective of this systematic review was to use evidence-based medicine to assess whether preoperative imaging or electromyography (EMG) predicts surgical outcomes in patients undergoing cervical surgery., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to the preoperative imaging and EMG. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Preoperative MR imaging and CT myelography are successful in confirming clinical radiculopathy (Class II). Multilevel T2 hyperintensity, T1 focal hypointensity combined with T2 focal hyperintensity, and spinal cord atrophy each convey a poor prognosis (Class III). There is conflicting data concerning whether focal T2 hyperintensity or cervical stenosis are associated with a worse outcome. Electromyography has mixed utility in predicting outcome (Class III)., Conclusions: Magnetic resonance imaging or CT myelography are important for preoperative assessment. Magnetic resonance imaging may be helpful in assessing prognosis, whereas EMG has mixed utility in assessing outcome.

Object: The objective of this systematic review was to use evidence-based medicine to identify valid, reliable, and responsive measures of functional outcome after treatment for cervical degenerative disease., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to functional outcomes. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Myelopathy Disability Index, Japanese Orthopaedic Association scale, 36-Item Short Form Health Survey, and gait analysis were found to be valid and reliable measures (Class II) for assessing cervical spondylotic myelopathy. The Patient-Specific Functional Scale, the North American Spine Society scale, and the Neck Disability Index were found to be reliable, valid, and responsive (Class II) for assessing radiculopathy for nonoperative therapy. The Cervical Spine Outcomes Questionnaire was a reliable and valid method (Class II) to assess operative therapy for cervical radiculopathy., Conclusions: Several functional outcome measures are available to assess cervical spondylotic myelopathy and cervical radiculopathy.

Object: The objective of this systematic review was to use evidence-based medicine to examine the diagnostic and therapeutic utility of intraoperative electrophysiological (EP) monitoring in the surgical treatment of cervical degenerative disease., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to cervical spine surgery and EP monitoring. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: The reliance on changes in EP monitoring as an indication to alter a surgical plan or administer steroids has not been observed to reduce the incidence of neurological injury during routine surgery for cervical spondylotic myelopathy or cervical radiculopathy (Class III). However, there is an absence of study data examining the benefit of altering a surgical plan due to EP changes., Conclusions: Although the use of EP monitoring may serve as a sensitive means to diagnose potential neurological injury during anterior spinal surgery for cervical spondylotic myelopathy, the practitioner must understand that intraoperative EP worsening is not specific-it may not represent clinical worsening and its recognition does not necessarily prevent neurological injury, nor does it result in improved outcome (Class II). Intraoperative improvement in EP parameters/indices does not appear to forecast outcome with reliability (conflicting Class I data).

Object: The objective of this systematic review was to use evidence-based medicine to delineate the natural history of cervical spondylotic myelopathy (CSM) and identify factors associated with clinical deterioration., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to the natural history of CSM. Abstracts were reviewed and studies meeting the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons., Results: The natural history of CSM is mixed: it may manifest as a slow, stepwise decline or there may be a long period of quiescence (Class III). Long periods of severe stenosis are associated with demyelination and may result in necrosis of both gray and white matter. With severe and/or long lasting CSM symptoms, the likelihood of improvement with nonoperative measures is low. Objectively measurable deterioration is rarely seen acutely in patients younger than 75 years of age with mild CSM (modified Japanese Orthopaedic Association scale score > 12; Class I). In patients with cervical stenosis without myelopathy, the presence of abnormal electromyography findings or the presence of clinical radiculopathy is associated with the development of symptomatic CSM in this patient population (Class I)., Conclusions: The natural history of CSM is variable, which may affect treatment decisions.

Object: The objective of this systematic review was to use evidence-based medicine to examine the efficacy of cervical laminoplasty in the treatment of cervical spondylotic myelopathy (CSM)., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical laminoplasty and CSM. Abstracts were reviewed and studies meeting the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons and Congress of Neurological Surgeons., Results: Cervical laminoplasty has improved functional outcome in the setting of CSM or ossification of the posterior longitudinal ligament. Using the Japanese Orthopaedic Association scale score, approximately 55-60% average recovery rate has been observed (Class III). The functional improvement observed after laminoplasty may be limited by duration of symptoms, severity of stenosis, severity of myelopathy, and poorly controlled diabetes as negative risk factors (Class II). There is conflicting evidence regarding age, with 1 study citing it as a negative risk factor, and another not demonstrating this result., Conclusions: Cervical laminoplasty is recommended for the treatment of CSM or ossification of the posterior longitudinal ligament (Class III).

Object: The objective of this systematic review was to use evidence-based medicine to assess whether clinical factors predict surgical outcomes in patients undergoing cervical surgery., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to clinical preoperative factors. Abstracts were reviewed, and studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Preoperative sensory-evoked potentials may aid in providing prognostic information in selected patients in whom clinical factors do not provide clear guidance (Class II). Age, duration of symptoms, and preoperative neurological function may commonly affect outcome (Class III)., Conclusions: Age, duration of symptoms, and preoperative neurological function should be discussed with patients when surgical intervention for cervical spondylotic myelopathy is considered. Preoperative sensory-evoked potentials may be considered for patients in whom clinical factors do not provide clear guidance if such information would potentially change therapeutic decisions.

Object: The objective of this systematic review was to use evidence-based medicine to examine the efficacy of anterior cervical surgery for the treatment of cervical spondylotic myelopathy (CSM)., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to anterior cervical surgery and CSM. Abstracts were reviewed, and studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Mild CSM (modified Japanese Orthopaedic Association [mJOA] scale scores > 12) responds in the short term (3 years) to either surgical decompression or nonoperative therapy (prolonged immobilization in a stiff cervical collar, "low-risk" activity modification or bed rest, and antiinflammatory medications) (Class II). More severe CSM responds to surgical decompression with benefits being maintained a minimum of 5 years and as long as 15 years postoperatively (Class III)., Conclusions: Treatment of mild CSM may involve surgical decompression or nonoperative therapy for the first 3 years after diagnosis. More severe CSM (mJOA scale score

Object: The objective of this systematic review was to use evidence-based medicine to identify the best methodology for diagnosis and treatment of anterior pseudarthrosis., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to pseudarthrosis and cervical spine surgery. Abstracts were reviewed, after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Evaluation for pseudarthrosis is warranted, as there may be an association between clinical outcome and pseudarthrosis. The strength of this association cannot be accurately determined because of the variable incidence of symptomatic and asymptomatic pseudarthroses (Class III). Revision of a symptomatic pseudarthrosis may be considered because arthrodesis is associated with improved clinical outcome (Class III). Both posterior and anterior approaches have proven successful for surgical correction of an anterior pseudarthrosis. Posterior approaches may be associated with higher fusion rates following repair of an anterior pseudarthrosis (Class III)., Conclusions: If suspected, pseudarthrosis should be investigated because there may be an association between arthrodesis and outcome. However, the strength of this association cannot be accurately determined. Anterior and posterior approaches have been successful.

Object: The objective of this systematic review was to use evidence-based medicine to identify the best methodology for radiographic assessment of cervical subaxial fusion., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical fusion. Abstracts were reviewed and studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Pseudarthrosis is best assessed through the absence of motion detected between the spinous processes on dynamic radiographs (Class II). The measurement of interspinous distance on dynamic radiographs of >or= 2 mm is a more reliable indicator for pseudarthrosis than angular motion of 2 degrees based on Cobb angle measurements (Class II). Similarly, it is also understood that the pseudarthrosis rate will increase as the threshold for allowable motion on dynamic radiographs decreases. The combination of interspinous distance measurements and identification of bone trabeculation is unreliable when performed by the treating surgeon (Class II). Identification of bone trabeculation on static radiographs should be considered a less reliable indicator of cervical arthrodesis than dynamic films (Class III)., Conclusions: Consideration should be given to dynamic radiographs and interspinous distance when assessing for pseudarthrosis.

Object: The objective of this systematic review was to use evidence-based medicine to examine the efficacy of posterior laminoforaminotomy in the treatment of cervical radiculopathy., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to posterior laminoforaminotomy and cervical radiculopathy. Abstracts were reviewed, and studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations which contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Posterior laminoforaminotomy improves clinical outcome in the treatment of cervical radiculopathy resulting from soft lateral cervical disc displacement or cervical spondylosis with resulting narrowing of the lateral recess. All studies were Class III. The most frequent design flaw involved the lack of utilization of validated outcomes measures. In addition, few historical studies included a detailed preoperative analysis of the patients. As such, the vast majority of studies that included both pre- and postoperative assessments with legitimate outcomes measures have been performed since 1990., Conclusions: Posterior laminoforaminotomy is an effective treatment for cervical radiculopathy.

Object: The objective of this systematic review was to use evidence-based medicine to examine the efficacy of cervical laminectomy for the treatment of cervical spondylotic myelopathy (CSM)., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical laminectomy and CSM. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: Laminectomy has improved functional outcome for symptomatic cervical myelopathy (Class III). The limitations of the technique are an increased risk of postoperative kyphosis compared to anterior techniques or laminoplasty or laminectomy with fusion (Class III). However, the development of kyphosis may not necessarily to diminish the clinical outcome (Class III)., Conclusions: Laminectomy is an acceptable therapy for near-term functional improvement of CSM (Class III). It is associated with development of kyphosis, however.

Object: The objective of this systematic review was to use evidence-based medicine to compare the efficacy of different surgical techniques for the treatment of cervical spondylotic myelopathy (CSM)., Methods: The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to anterior and posterior cervical spine surgery and CSM. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons., Results: A variety of techniques have improved functional outcome after surgical treatment for CSM, including anterior cervical discectomy with fusion (ACDF), anterior cervical corpectomy with fusion (ACCF), laminoplasty, laminectomy, and laminectomy with fusion (Class III). Anterior cervical discectomy with fusion and ACCF appear to yield similar results in multilevel spine decompression for lesions at the disc level. The use of anterior plating allows for equivalent fusion rates between these techniques (Class III). If anterior fixation is not used, ACCF may provide a higher fusion rate than multilevel ACDF but also a higher graft failure rate than multilevel ACDF (Class III). Anterior cervical discectomy with fusion, ACCF, laminectomy, laminoplasty, and laminectomy with arthrodesis all provide near-term functional improvement for CSM. However, laminectomy is associated with late deterioration compared with the other types of anterior and posterior surgeries (Class III)., Conclusions: Multiple approaches exist with similar near-term improvements; however, laminectomy appears to have a late deterioration rate that may need to be considered when appropriate.

Object: Interspinous process decompression (IPD) theoretically relieves narrowing of the spinal canal and neural foramen in extension and thus reduces the symptoms of neurogenic intermittent claudication (NIC). The purpose of this study was to compare the efficacy of IPD with nonoperative treatment in patients with NIC secondary to degenerative spondylolisthesis., Methods: The authors conducted a randomized controlled study in patients with NIC; they compared the results obtained in patients treated with the X STOP IPD device with those acquired in patients treated nonoperatively. The X STOP implant is a titanium alloy device that is placed between the spinous processes to reduce the canal and foraminal narrowing that occurs in extension. In a cohort of 75 patients with degenerative spondylolisthesis, 42 underwent surgical treatment in which the X STOP IPD device was placed and 33 control individuals were treated nonoperatively. Patients underwent serial follow-up evaluations. The Zurich Claudication Questionnaire (ZCQ), 36-Item Short Form Health Survey (SF-36), and radiographic assessment were used to determine outcomes. Two-year follow-up data were obtained in 70 of 75 patients. Statistically significant improvement in ZCQ and SF-36 scores was seen in X STOP device-treated patients but not in the nonoperative control patients at all postoperative intervals. Overall clinical success occurred in 63.4% of X STOP device-treated patients and only 12.9% of controls. Spondylolisthesis and kyphosis were unaltered., Conclusions: The X STOP device was more effective than nonoperative treatment in the management of NIC secondary to degenerative lumbar spondylolisthesis.

Object: Total joint arthroplasties most commonly fail because the implant becomes worn and a host inflammatory response subsequently develops. Both the material response to the biological environment and the host response to the device must be thoroughly evaluated to establish the efficacy of cervical arthroplasty. Analyses of devices explanted in humans allow evaluation of both responses. Hypothetical wear rates can be determined by comparing in vivo wear with simulator-derived wear. The purpose of this study was to perform explant analyses involving the Bryan and Prestige discs and compare these results with those obtained using spine simulators., Methods: Of the approximately 5500 patients treated with the Bryan disc, 11 have undergone explantation of the device. Six of these devices were analyzed for dimensional and chemical changes. Three of the approximately 300 implanted Prestige discs were retrieved, and two were examined microscopically. Histological specimens were assessed for wear particles and host inflammatory response. Additionally, the extent of simulator-produced wear was compared with that demonstrated in the retrieved specimens., Conclusions: The simulator-generated results predict adequate wear-related characteristics for both the Bryan and Prestige prostheses for a minimum of 40 years. Comparison of data with those of the retrieved specimens indicates that the wear was more minimal than predicted in simulators by five- to 10-fold. In no instance did the revisions result from failure of the device due to a reaction to wear debris, fracture, polymer oxidation, or metal corrosion. The inflammatory response seen in the periprosthetic tissues was minimal and not characteristic of inflammatory responses in failed diarthrodial joint arthroplasties.