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Study designMulti-institutional retrospective study.ObjectiveThe goal of the current study is to quantify the incidence of 2 extremely rare complications of cervical spine surgery; hypoglossal and glossopharyngeal nerve palsies.MethodsA total of 8887 patients who underwent cervical spine surgery from 2005 to 2011 were included in the study from 21 institutions.ResultsNo glossopharyngeal nerve injuries were reported. One hypoglossal nerve injury was reported after a C3-7 laminectomy (0.01%). This deficit resolved with conservative management. The rate by institution ranged from 0% to 1.28%. Although not directly injured by the surgical procedure, the transient nerve injury might have been related to patient positioning as has been described previously in the literature.ConclusionsHypoglossal nerve injury during cervical spine surgery is an extremely rare complication. Institutional rates may vary. Care should be taken during posterior cervical surgery to avoid hyperflexion of the neck and endotracheal tube malposition.

Study Design: Prospective non-randomized single-center cohort study. Objectives: To analyze the quality of postoperative magnetic resonance imaging of 2 structurally different cervical disc arthroplasty devices at the index and adjacent levels. Methods: A non-randomized, comparative, prospective, single-center study included 40 patients (23 men and 17 women) aged 32 (26-40) years. Two study groups were utilized: in the first (n = 20), a titanium prosthesis was used; in the second (n = 20), a cobalt-chromium implant was used. Evaluation of MRI studies before and after surgery was performed using sagittal and axial T2 weighted images by 2 specialists who were blinded to the prosthesis that was used. To determine the quality of an MRI image, the classification of Jarvik 2000, the radiological and orthopedic scales for assessing artifacts were used. Results: There was good-to-excellent inter-observer agreement for all of the MR parameters used for the titanium and satisfactory-to-good for the cobalt chromium group. The analysis of the quality of postoperative imaging using the Jarvik 2000 scale showed a statistically significant deterioration in MR images in the cobalt chromium group (P < 0.001), compared to the titanium (P = 0.091). Following a single-level total arthroplasty, the titanium group had better MRI images according to radiological and orthopedic scales (P < 0.001). Conclusion: Titanium cervical disc arthroplasty devices result in superior postoperative MR imaging, as compared to cobalt chromium prostheses, as the latter significantly reduces image quality due to the pronounced ferromagnetic effect. [ABSTRACT FROM AUTHOR]

Study design: Retrospective cohort study. Objective: Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis. Methods: A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC. Results: 298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs. Conclusion: This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team. [ABSTRACT FROM AUTHOR]

Background: Several cervical laminectomy techniques have been described. One commonly used method involves making bilateral trough laminotomies using either a Kerrison rongeur or a high speed burr, and then removing the lamina en-bloc. Alternatively, some surgeons prefer to thin the lamina with the burr, and then remove the lamina in a piecemeal fashion using Kerrison rongeurs. Some surgeons have warned against the potential risk of iatrogenic spinal cord injury from inserting the Kerrison footplate into a stenotic canal. We aim to quantify the amount of canal encroachment for various methods of cervical laminectomies. Methods: Three attending spine surgeons and two fellows each performed laminectomies using C5 sawbones models. The canal was completely filled with modeling putty to simulate a stenotic spinal cord. Bilateral trough laminotomies were performed using a 1 mm Kerrison, a 2 mm Kerrison, and a 3 mm matchstick high-speed burr. Piecemeal laminectomies were performed with a 2 mm Kerrison. A blinded spine surgery fellow performed all quantitative measurements. Three blinded researchers qualitatively ranked the amount of "canal encroachment". Results: The average canal encroachment was 0.50 ± 0.45mm for the burr, 1.37 ± 0.68 mm for the 1 mm Kerrison, and 1.47 ± 0.37 mm for the 2 mm Kerrison (p =.002). There was a statistically significant difference between the burr and 1 mm Kerrison (p =.01) and between the burr and the 2 mm Kerrison (p =.001). There was no statistical difference between the 1 mm and 2 mm Kerrison (p =.78). The mean rank of the burr group, the Kerrison rongeur group, and the piecemeal group were 1.41, 1.94, and 2.65, respectively, on an ordinal scale of 1–3. Conclusion: When performing a trough laminotomy, the high-speed burr results in less canal encroachment compared to 1 mm or 2 mm Kerrison rongeurs. In the setting of a stenotic spinal canal, spine surgeons should consider using the burr to perform laminectomy to minimize the degree of canal encroachment. [ABSTRACT FROM AUTHOR]

Purpose: There have been a few previous reports regarding the distances between the medial borders of the longus colli to expose the disc space. However, to our knowledge, there are no reports concerning longus colli dissection to expose the uncinate processes. This study was undertaken to assess the surgical relationship between the longus colli muscle and the uncinate process in the cervical spine. Materials and Methods: This study included 120 Korean patients randomly selected from 333 who had cervical spine MRIs and CTs from January 2003 to October 2013. They consisted of 60 males and 60 females. Each group was subdivided into six groups by age from 20 to 70 years or more. We measured three parameters on MRIs from C3 to T1: left and right longus colli distance and inter-longus colli distance. We also measured three parameters on CT: left and right uncinate distance and inter-uncinate distance. Results: The longus colli distances, uncinate distances, and inter-uncinate distances increased from C3 to T1. The inter-longus colli distances increased from C3 to C7. There was no difference in longus colli distances and uncinate distances between males and females. There was no difference in the six parameters for the different age groups. Conclusion: Although approximate guidelines, we recommend the longus colli be dissected approximately 5 mm at C3-5, 6 mm at C5-6, 7 mm at C6-7, and 8 mm at C7-T1 to expose the uncinate process to its lateral edge. [ABSTRACT FROM AUTHOR]

Abstract: Background context: Although numerous studies have reported on the loss of flexion-extension range of motion (ROM) associated with laminoplasty, few have reported on the time course of this loss of motion for a long-term follow-up period. Purpose: We previously reported our early data on postlaminoplasty cervical ROM. In this article, we describe our minimum 5-year follow-up data to identify the time-dependent change in ROM after cervical laminoplasty. Study design: A prospective cohort study. Patient sample: The procedure was performed in 23 patients. Eighteen patients with a minimum 5-year follow-up were included in the study. Outcome measures: The time-dependent neck ROM changes observed in the neutral, flexion, and extension radiographs were used to measure the radiological outcome. The Japanese Orthopaedic Association classification and a numerical rating scale of axial neck pain and arm pain were used to evaluate clinical outcome. Methods: Twenty-three patients who received unilateral open-door laminoplasties, including miniplate fixation over three levels, were serially evaluated at regular set intervals postoperatively. Eighteen patients with a minimum 5-year follow-up were included in the study. The mean follow-up period was 68.1 months (range, 60–78 months). Nine patients had ossification of posterior longitudinal ligament (OPLL) and nine patients had cervical spondylotic myelopathy (CSM). Enrolled patients were divided into subgroups (OPLL vs. CSM; autofusion vs. nonautofusion) to compare the ROM between the groups. We evaluated the time-dependent neck ROM changes by taking neutral, flexion, and extension radiographs preoperatively and at 1, 3, 6, 9, 12, 18, and 24 months postoperatively. Follow-up radiographs were taken annually after a 2-year follow-up. Results: The preoperative and 1-, 3-, 6-, 12-, 24-, 36-, 48-, and 60-month postoperative ROM figures were 39.9±11.2°, 35.0±9.2°, 33.0±11.0°, 30.1±10.4°, 25.8±13.1°, 24.7±10.0°, 23.8±6.5°, 24.6±8.3°, and 23.6±9.4°, respectively, and at the most recent follow-up, ROM was 24.5±10.1°. Thus, the mean ROM decreased by 15.4±8.4° (38.5%) by the last follow-up (p<.0001). In the OPLL group, we observed a more limited cervical ROM than in the CSM group (47.2% vs. 72.7%). As expected, in the laminar autofusion group, the ROM decreased significantly (55.6% decrease), whereas in the nonautofusion group, the ROM decreased less significantly (13.4% decrease) at the last follow-up. Postoperative axial pain did not correlate with the cervical ROM. Conclusions: These results suggest that the loss of cervical ROM after laminoplasty is time-dependent, and patients with OPLL and laminar autofusion had less ROM. Postlaminoplasty ROM reduction can recover after several years, unless laminar autofusion occurs. [Copyright &y& Elsevier]

Ankylosing spondylitis is an inflammatory disorder that can produce disabling musculoskeletal conditions. Spinal deformity is among the most common manifestations. Cervical kyphosis can be particularly debilitating to the patient because of interference with forward gaze and activities of daily living. In addition, cervical deformity can lead to both neurologic and respiratory deterioration. For many patients, the only treatment option is surgery. Both the Smith-Petersen osteotomy and the pedicle subtraction osteotomy have been used successfully to manage cervical deformity in patients with ankylosing spondylitis. These procedures are technically difficult and carry significant risk but can produce excellent and safe outcomes. [ABSTRACT FROM AUTHOR]

Abstract: Background context: Postlaminectomy kyphosis of the cervical spine is a challenging condition to treat because it has a combination of an exposed cord, progressive kyphosis, segmental instability, and anterior neural compression. The ideal mode of surgical correction remains controversial. In terms of surgical strategy, there are few large series that have reported the long-term results of anterior surgical treatment of this condition. Purpose: This study was designed to determine the long-term results and outcomes of anterior surgical treatment alone for the patients of postlaminectomy cervical kyphosis. Study design/setting: This is a retrospective review of prospectively collected data in an academic institution. Patient sample: The sample comprises 23 patients who underwent anterior reconstruction surgery for the treatment of postlaminectomy kyphosis. Outcome measures: The outcome measures were neck disability index (NDI), visual analog scale (VAS) for neck and arm pain, Nurick grades, kyphosis angles, fusion status, and complications. Methods: Two independent spine surgeons reviewed the completed medical records and radiographs of 23 patients who had undergone multilevel anterior cervical hybrid decompression (corpectomy and discectomy) with instrumented fusions for postlaminectomy kyphosis by one surgeon at an academic institution. The clinical and radiographic outcomes were measured by NDI, VAS for neck and arm pain, Nurick grades, kyphosis angles, and fusion status at the time of preoperative, postoperative, and the last follow-up. Results: The mean follow-up was 44.5±31.0 months (range 24–120 months). The average preoperative kyphosis of 20.9° was significantly improved to a lordosis of 14.0° after surgery (p<.0001) and was maintained to a lordosis of 9.6° at the final follow-up (p<.0001). The average correction angle of kyphosis was 30.5±11.7°. The average preoperative, NDI, VAS, and Nurick grades were significantly improved at the last follow-up (all, p<.0001). The average levels of 0.9±0.7 corpectomy, 2.0±0.9 discectomy, and 3.8±1.4 anterior fusions were performed in each patient. Solid fusion was confirmed by computed tomography in all patients at a mean time of 3.8±1.2 months. There were six (26%) patients and seven (30.4%) complications: four (14.3%) graft-related complications (one implant displacement, one graft dislodgment, and one pseudarthrosis), one swallowing difficulty, one wound infection, one dura tear, and one pneumonia. Conclusions: Our data suggest that multilevel anterior surgical treatment using hybrid decompression (corpectomy and discectomy) combined with instrumented fusion yields acceptable clinical and neurological improvement and effective correction of cervical kyphosis. The techniques used also appeared to decrease the incidence of graft-related complications compared with a previous report by the same author. [Copyright &y& Elsevier]

Abstract: Background context: Cervical facet arthrosis has been implicated as a cause for neck pain, radiculopathy, occipital headache, and ear pain. Purpose: The objective of this study was to examine the occurrence of facet arthrosis in the cervical spine. Study design/setting: This study examined cadaveric specimens from the Hamann Todd Collection. Patient sample: None. Outcomes measures: None. Materials and methods: Four hundred sixty-five skeletally mature human cervical spines from the Hamann Todd Collection in the Cleveland Museum of Natural History were obtained for analysis. We analyzed the facets for arthrosis. We graded no arthrosis as Grade 0. Facets with peripheral osteophytic reaction, but with no lateral mass distortion were graded as Grade 1. Facets with peripheral osteophytic reaction and lateral mass distortion were graded as Grade 2. Facets that were ankylosed were graded as Grade 3. Each specimen was examined bilaterally at levels from C2–C3 through C6–C7, yielding 4,650 specimen assessments. The data were analyzed to compare cervical levels, gender, facet side, age groups, and race. Proportion analysis, using the Fisher exact test, was used to assess for statistical difference between various groupings. Results: In the entire population of 465 specimens, the upper cervical specimens appeared to be affected by facet arthrosis more frequently than the lower levels; 12.37% of the specimens had bony evidence of arthrosis at the C2–C3 level; 13.33% of the specimens had arthrosis occur at the C3–C4 level; 14.62% at the C4–C5 level; 7.85% at the C5–C6 level, and 4.84% at the C6–C7 level. The large majority of all cervical facet arthrosis was found to be Grade 1 at all levels. In the older population, the prevalence of facet arthrosis is as high as 29.87% for the C4–C5 level. C4–C5 level appears to be affected the most frequently, followed by the C3–C4 level, then C2–C3, C5–C6, and C6–C7. Conclusion: The prevalence of cervical facet arthrosis increases with age, and occurs more commonly in the upper cervical spine. [Copyright &y& Elsevier]

Objectives: Anterior cervical spine procedures carry an inherent risk of recurrent laryngeal nerve (RLN) injury. Patients with persistent RLN paresis may be asymptomatic because of compensation from the opposite side. If such patients undergo an opposite-side anterior approach for revision surgery, they are at risk for a second RLN injury, creating the potential for bilateral vocal fold paresis and possible need for tracheotomy. A program of routine screening for laryngeal paresis was implemented for these patients. This retrospective study reviews the results of this screening process. Methods: Patients referred for preoperative laryngeal nerve screening were identified. Their charts were reviewed for the results of the videolaryngoscopic examination, and for any recommendations made based on the findings. Relevant history and other physical findings were recorded. Results: Fifty screening laryngeal examinations were performed in 47 patients, of whom 31(66%) had previously under- gone a single anterior cervical approach procedure, and 16 (34%) had undergone more than one. Thirteen of the examinations (26%) revealed abnormal laryngeal findings, including paresis or paralysis in 11 cases (22%), of which 5 were asymptomatic. The findings resulted in a recommendation of a cervical approach from the already-involved side. None of the revision procedures resulted in bilateral vocal fold paralysis. The risk of laryngeal nerve injury appears to increase as higher cervical levels are approached. Conclusions: Minimally symptomatic injuries of the laryngeal nerves from prior neck surgery create a potential serious risk of bilateral vocal fold paralysis with subsequent procedures. Preoperative laryngeal screening is a simple and effective method for reducing this risk. [ABSTRACT FROM AUTHOR]

Fractures of the odontoid process of the second cervical vertebra represent one of the most common and controversial injury types affecting the cervical spine. These fractures are observed in nearly all age groups but the incidence peaks in young adults and the elderly. The rate of associated spinal cord injury is considered relatively low but is not insignificant at approximately 20% of cases. Achieving osseous healing and long-term stability are principal concerns, although fibrous nonunion may provide adequate stability in certain patient populations such as low-demand elderly patients. Following careful scrutiny of radiological studies and thoughtful consideration of clinical factors, various treatment plans often remain viable options for any given patient. While nonsurgical management is always appealing when appropriate, early surgery frequently provides an ideal opportunity to achieve stable fracture healing without functional compromise. In most cases, early surgery also restores sufficient immediate stability to allow rapid patient mobilization without the need for external orthoses or halo vest immobilization, thereby reducing the risk of medical complications related to prolonged recumbency. [ABSTRACT FROM AUTHOR]

The article discusses the methods in assessing the cervical deformity. It states that first it has to be identiffied that if the malalignment is a rigid deformity cause by a fused spine then it require osteotomy, or a flexible one then it can be corrected with soft tissue release and instrumentation. The article further favours anterior-posterior osteotomy to correct rigid deformities.

Study Design. Description of surgical technique with case series. Objective. To describe the surgical management of fixed cervical deformities using an anterior osteotomy of the cervical spine. Summary of Background Data. Although posteriorly based osteotomies of the cervical spine have been described in the past, there are no reports of the surgical technique for performing an anterior osteotomy of the cervical spine for fixed cervical deformities. Methods. Description of a single surgeon's technique for performing an anterior cervical osteotomy and his experience in performing this technique from 2000 to 2010 in a consecutive series of patients. Demographics, operative details, and clinical/radiographical outcomes were collected. The cohort was separated into 2 groups. Group 1 had anterior osteotomy only with or without posterior instrumentation whereas group 2 had anterior osteotomy and Smith-Petersen osteotomies with posterior instrumentation. Results. A total of 38 patients (group 1=17, group 2 = 21) underwent an anterior osteotomy in the study period with an average follow-up of 3.4 years (range, 1.0-6.3 yr). All but 7 cases were revision cases. Group 1 had shorter length of surgery and less estimated blood loss than group 2 (length of surgery 220 vs. 313 min, P < 0.01; estimated blood loss 189 vs. 294 mL, P = 0.02). The mean angular correction achieved in group 1 was less than that of group 2, although not statistically significant (23° vs. 33°, P = 0.15). There was less mean translational correction achieved in group 1 compared with group 2 (1.3 vs. 3.7 cm, P = 0.03). Both groups had improvements in the neck disability index with surgery and were similar between groups (20 vs. 19.7, P = 0.78). There were no neurological complications or intraoperative neuromonitoring changes in either group. Conclusion. The use of an anterior osteotomy in the cervical spine is safe and effective for the correction of fixed deformities of the cervical spine. When necessary, Smith-Petersen osteotomies can add to the angular and translational correction to achieve a satisfying outcome for patients. [ABSTRACT FROM AUTHOR]

Study Design: Cross-sectional study.Objective: The purpose of this study is to develop and validate a machine learning algorithm for the automated identification of anterior cervical discectomy and fusion (ACDF) plates from smartphone images of anterior-posterior (AP) cervical spine radiographs.Summary Of Background Data: Identification of existing instrumentation is a critical step in planning revision surgery for ACDF. Machine learning algorithms that are known to be adept at image classification may be applied to the problem of ACDF plate identification.Methods: A total of 402 smartphone images containing 15 different types of ACDF plates were gathered. Two hundred seventy-five images (∼70%) were used to train and validate a convolution neural network (CNN) for classification of images from radiographs. One hundred twenty-seven (∼30%) images were held out to test algorithm performance.Results: The algorithm performed with an overall accuracy of 94.4% and 85.8% for top-3 and top-1 accuracy, respectively. Overall positive predictive value, sensitivity, and f1-scores were 0.873, 0.858, and 0.855, respectively.Conclusion: This algorithm demonstrates strong performance in the classification of ACDF plates from smartphone images and will be deployed as an accessible smartphone application for further evaluation, improvement, and eventual widespread use.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background Context: High quality evidence is difficult to generate, leaving substantial knowledge gaps in the treatment of spinal conditions. Appropriate use criteria (AUC) are a means of determining appropriate recommendations when high quality evidence is lacking.Purpose: Define appropriate use criteria (AUC) of cervical fusion for treatment of degenerative conditions of the cervical spine.Study Design/setting: Appropriate use criteria for cervical fusion were developed using the RAND/UCLA appropriateness methodology. Following development of clinical guidelines and scenario writing, a one-day workshop was held with a multidisciplinary group of 14 raters, all considered thought leaders in their respective fields, to determine final ratings for cervical fusion appropriateness for various clinical situations.Outcome Measures: Final rating for cervical fusion recommendation as either "Appropriate," "Uncertain" or "Rarely Appropriate" based on the median final rating among the raters.Methods: Inclusion criteria for scenarios included patients aged 18 to 80 with degenerative conditions of the cervical spine. Key modifiers were defined and combined to develop a matrix of clinical scenarios. The median score among the raters was used to determine the final rating for each scenario. The final rating was compared between modifier levels. Spearman's rank correlation between each modifier and the final rating was determined. A multivariable ordinal regression model was fit to determine the adjusted odds of an "Appropriate" final rating while adjusting for radiographic diagnosis, number of levels and symptom type. Three decision trees were developed using decision tree classification models and variable importance for each tree was computed.Results: Of the 263 scenarios, 47 (17.9 %) were rated as rarely appropriate, 66 (25%) as uncertain and 150 (57%) were rated as appropriate. Symptom type was the modifier most strongly correlated with the final rating (adjusted ρ2 = 0.58, p<.01). A multivariable ordinal regression adjusting for symptom type, diagnosis, and number of levels and showed high discriminative ability (C statistic = 0.90) and the adjusted odds ratio (aOR) of receiving a final rating of "Appropriate" was highest for myelopathy (aOR, 7.1) and radiculopathy (aOR, 4.8). Three decision tree models showed that symptom type and radiographic diagnosis had the highest variable importance.Conclusions: Appropriate use criteria for cervical fusion in the setting of cervical degenerative disorders were developed. Symptom type was most strongly correlated with final rating. Myelopathy or radiculopathy were most strongly associated with an "Appropriate" rating, while axial pain without stenosis was most associated with "Rarely Appropriate." [ABSTRACT FROM AUTHOR]

Background Context: The typically accepted surgical procedure for cervical disc pathology has been the anterior cervical discectomy and fusion (ACDF), although recent trials have demonstrated equivalent or improved outcomes with cervical disc arthroplasty (CDA). Trends for these two procedures regarding utilization, revision procedures, and other demographic information have not been sufficiently explored.Purpose: The present study aims to provide data regarding ACDF and CDA from 2006 to 2013 in the United States.Design: The present study is a retrospective national database analysis.Patient Sample: The present study included 20% sample of discharges from US hospitals, which is weighted to provide national estimates.Outcome Measures: Functional measures such as national incidence, hospital costs, length of stay (LOS), routine discharge, revision burden, and patient characteristics were used in the present study.Methods: Patients from the National Inpatient Sample (NIS) database who underwent primary ACDF, revision ACDF, primary CDA, and revision CDA from 2006 to 2013 were included. Demographic and economic data for the procedures' respective International Classification of Diseases, Ninth Revision, Clinical Modification codes were collected.Results: A total of 1,059,403 ACDF and 13,099 CDA surgeries were performed in the United States from 2006 to 2013. The annual number of ACDF increased by 5.7% nonlinearly from 120,617 in 2006 to 127,500 in 2013 (mean per year 132,425; range 120,617-147,966); CDA increased by 190% nonlinearly from 540 in 2006 to 1,565 in 2013 (mean per year 1,637; range 540-2,381). Cervical disc arthroplasty patients were younger and had more private or "other" insurance, including worker's compensation (p<.0001). Mean LOS was longer for ACDF (ACDF 2.3 days vs. CDA 1.5; p<.0001). Routine discharge was higher in the CDA group (CDA 96% vs. ACDF 89%; p-value<.0001). The mean hospital-related cost was more expensive for ACDF (ACDF $16,178 vs. CDA $13,197; p-value=.0007). Cervical disc arthroplasty mean revision burden, defined as the ratio of revision procedures to the sum of primary and revision procedures, was greater (CDA 5.9% vs. ACDF 2.3%, p-value=.01).Conclusions: Nationally approximately 132,000 ACDFs are done each year compared with only 1,600 CDAs. The number of ACDF surgeries performed far outpaces CDA by a ratio of 81:1 in the United States without a clear direction in the trend for utilization given recent fluctuations. Cervical disc arthroplasty revision burden was more than double compared with the ACDF revision burden (5.9% vs. 2.3%), which was not accounted for by patient baseline demographics. The etiologies of these findings are likely multifactorial and require further research. [ABSTRACT FROM AUTHOR]

Study Design. A retrospective study. Objective. The purpose of this study was to determine, using survivorship analysis, the rate of adjacent segment pathology (ASP) development and to identify the risk factors for reoperation. Summary of Background Data. The study of Hilibrand defined "adjacent segment disease" as symptomatic radiculopathy or myelopathy due to an adjacent segment documented on 2 consecutive office visits. In addition to being somewhat subjective, their criterion is not as practical as identifying the rate of adjacent pathology by the need for reoperation. Methods. This was a retrospective analysis of 1038 consecutive patients who underwent primary anterior cervical spine arthrodesis for radiculopathy and/or myelopathy by 1 surgeon. Annual incidence and prevalence of ASP requiring surgery were calculated and survivorship was determined. We used the Cox regression for risk factor analysis. Results. Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.4% per year (95% confidence interval, 1.9-3.0). The Kaplan-Meier analysis predicted that 22.2% of patients would need reoperation at adjacent segments by 10 years postoperatively. Factors increasing the risk were smoking, female sex, and the number of arthrodesis segments. One or 2-segment arthrodesis had an 1.8 times greater risk than arthrodesis involving 3 or more segments. Age, neurological diagnosis, diabetes, Klippel-Feil syndrome, and noncontiguous segmental-type ossification of posterior longitudinal ligament were not significant risks. Conclusion. Patients treated with 1- or 2-segment anterior cervical arthrodesis are more likely to develop ASP than those treated with arthrodesis involving 3 or more segments. Smokers and women had a higher ASP reoperation rate. Our series, the largest in the literature, predicts that 22.2% of patients will require reoperation for ASP within 10 years, substantially higher than the Hilibrand study. [ABSTRACT FROM AUTHOR]

Background context The benefits of oblique magnetic resonance imaging (MRI) reformations to assess cervical neural foramina have been reported previously in clinical and cadaveric studies. But there is a paucity of literature investigating intra- and interobserver variabilities for assessing cervical foraminal stenosis using oblique MRI views. Purpose To determine the value of oblique MRI views compared with axial and sagittal views for assessing foraminal stenosis of the cervical spine using intra- and interobserver variabilities. Study design A retrospective study. Patient sample Twenty-six patients were included. Outcome measures Two independent reviewers blindly identified the presence of foraminal stenosis as definite or indeterminate on the sagittal, axial, and oblique views. The assessments using the different views were compared using an independent t test. Intra- and interobserver variabilities were assessed using Kappa analysis. Methods We evaluated the cervical spine MRIs of patients with varying degrees of foraminal stenosis. The mean age of the patients was 60.8 years (range 50–86 years). Male to female ratio was 16:10. The oblique images were obtained by reformatting the scans perpendicular to the long axis of the right and left neural foramina, respectively. Results The oblique or axial views had significantly greater confidence rates for determining the presence of foraminal stenosis than the sagittal views (92.3%, 88.1% vs. 58.0%, respectively, p=.000). The oblique view had significantly better intraobserver agreement than the sagittal and axial images. Both the axial and oblique views had significantly better interobserver agreement than the sagittal images. Conclusions Oblique MRI views of the cervical spine significantly reduce the degree of intra- and interobserver variabilities and increase observer confidence in the assessment of foraminal stenosis. Our results suggest that routine use of oblique cervical MRI views might be useful for evaluating cervical foraminal stenosis. [ABSTRACT FROM AUTHOR]

Abstract: Background context: Postoperative malalignment of the cervical spine may alter cervical spine mechanics and put patients at risk for clinical adjacent segment pathology requiring surgery. Purpose: To investigate whether a relationship exists between cervical spine sagittal alignment and clinical adjacent segment pathology requiring surgery (CASP-S) following anterior cervical fusion (ACF). Study design: Retrospective matched study. Patient sample: A total of 122 patients undergoing ACF between 1996 and 2008 were identified, with a minimum of 2 years of follow-up. Outcome measures: Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior end plate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. Methods: A total of 122 patients undergoing ACF between 1996 and 2008 were identified, with a minimum of 1 year of follow-up. Patients were divided into groups according to the development of CASP (control/CASP-S) and by number/location of levels fused. Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior end plate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. Appropriate statistical tests were performed to calculate relationships between the variables and the development of CASP-S. No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this article. Results: The groups were similar with regard to demographic and surgical variables. Lordosis was preserved in 82% (50/61) of the control group but in only 66% (40/61) of the CASP-S group (p=.033). More patients with a straight curve pattern developed CASP-S. The distance from the C2 to the C7 plumb line and T1 sagittal slope angle were lower in the CASP-S group with C5–C6 fusions compared with the control group. Also, the distance from C5–C6 fusion mass to C7 plumb line and C7 sagittal slope angle were lower in the CASP-S group with C5–C6 fusions. Conclusions: Our results suggest that malalignment of the cervical spine following an ACF at C5–C6 has an effect on the development of clinical adjacent segment pathology requiring surgery. [Copyright &y& Elsevier]

Study Design. Post hoc analysis of prospectively collected data. Objective. Development of methods to determine in vivo spinal cord dimensions and application to correlate preoperative alignment, myelopathy, and health-related quality-of-life scores in patients with cervical spondylotic myelopathy (CSM). Summary of Background Data. CSM is the leading cause of spinal cord dysfunction. The association between cervical alignment, sagittal balance, and myelopathy has not been well characterized. Methods. This was a post hoc analysis of the prospective, multicenter AOSpine North America CSM study. Inclusion criteria for this study required preoperative cervical magnetic resonance imaging (MRI) and neutral sagittal cervical radiography. Techniques for MRI assessment of spinal cord dimensions were developed. Correlations between imaging and health-related quality-of-life scores were assessed. Results. Fifty-six patients met inclusion criteria (mean age = 55.4 yr). The modified Japanese Orthopedic Association (mJOA) scores correlated with C2-C7 sagittal vertical axis (SVA) (r = -0.282, P = 0.035). Spinal cord volume correlated with cord length (r = 0.472, P < 0.001) and cord average cross-sectional area (r = 0.957, P < 0.001). For all patients, no correlations were found between MRI measurements of spinal cord length, volume, mean cross-sectional area or surface area, and outcomes. For patients with cervical lordosis, mJOA scores correlated positively with cord volume (r = 0.366, P = 0.022), external cord area (r = 0.399, P = 0.012), and mean cross-sectional cord area (r = 0.345, P = 0.031). In contrast, for patients with cervical kyphosis, mJOA scores correlated negatively with cord volume (r = -0.496, P = 0.043) and mean cross-sectional cord area (r = -0.535, P = 0.027). Conclusion. This study is the first to correlate cervical sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. It is interesting to note that sagittal balance but not kyphosis is tied to myelopathy score. Future work will correlate alignment changes to cord morphology changes and myelopathy outcomes. Summary Statements. This is the first study to correlate sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. [ABSTRACT FROM AUTHOR]

Study Design. Systematic review and survey. Objective. To perform an evidence synthesis of the literature and obtain information from the global spine care community assessing the frequency, timing, and predictors of symptom development in patients with radiographical evidence of cervical spinal cord compression, spinal canal narrowing, and/or ossification of posterior longitudinal ligament (OPLL) but no symptoms of myelopathy. Summary of Background Data. Evidence for a marker to predict symptom development remains sparse, and there is controversy surrounding the management of asymptomatic patients. Methods. We conducted a systematic review of the English language literature and an international survey of spine surgeons to answer the following key questions in patients with radiographical evidence of cervical spinal cord compression, spinal canal narrowing, and/or OPLL but no symptoms of myelopathy: (1) What are the frequency and timing of symptom development? (2) What are the clinical, radiographical, and electrophysiological predictors of symptom development? (3) What clinical and/or radiographical features influence treatment decisions based on an international survey of spine care professionals? Results. The initial literature search yielded 388 citations. Applying the inclusion/exclusion criteria narrowed this to 5 articles. Two of these dealt with the same population. For patients with spinal cord compression secondary to spondylosis, one study reported the frequency of myelopathy development to be 22.6%. The presence of symptomatic radiculopathy, cervical cord hyperintensity on magnetic resonance imaging, and prolonged somatosensory- and motor-evoked potentials were reported in one study as significant independent predictors of myelopathy development. In contrast, the lack of magnetic resonance imaging hyperintensity was found to be a positive predictor of early myelopathy development (≤12-mo follow-up). For subjects with OPLL, frequency of myelopathy development was reported in 3 articles and ranged from 0.0% to 61.5% of subjects. One of these studies reported canal stenosis of 60% or more, lateral deviated OPLL, and increased cervical range of motion as significant predictors of myelopathy development. In a survey of 774 spine surgeons, the majority deemed the presence of clinically symptomatic radiculopathy to predict progression to myelopathy in nonmyelopathic patients with cervical stenosis. Survey responses pertaining to 3 patient case vignettes are also presented and discussed in the context of the current literature. Conclusion. On the basis of these results, we provide a series of evidence-based recommendations related to the frequency, timing, and predictors of myelopathy development in asymptomatic patients with cervical stenosis secondary to spondylosis or OPLL. Future prospective studies are required to refine our understanding of this topic. Evidence-Based Clinical Recommendations. Recommendation. Patients with cervical canal stenosis and cord compression secondary to spondylosis, without clinical evidence of myelopathy, and who present with clinical or electrophysiological evidence of cervical radicular dysfunction or central conduction deficits seem to be at higher risk for developing myelopathy and should be counseled to consider surgical treatment. Overall Strength of Evidence. Moderate Strength of Recommendation. Strong Summary Statements. * Statement 1: On the basis of the current literature, for patients with cervical canal stenosis and cord compression secondary to spondylosis, without clinical evidence of myelopathy, approximately 8% at l-year follow-up and 23% at a median of 44-months follow-up develop clinical evidence of mye]opathy. * Statement 2: For patients with cervical canal stenosis and cord compression secondary to spondylosis, without clinical evidence of myelopathy, the absence of magnetic resonance imaging intramedu]]ary T2 hyperintensity has been shown to predict early myelopathy development (<12-rno follow-up) and the presence of such signal has been shown to predict late myelopathy development (mean 44-mo follow-up). In light of this discrepancy, no definite recommendation can be made surrounding the utility of this finding in predicting myelopathy development. * Statement 3: For patients with OPLL but without mye]opathy, no recommendation can be made regarding the incidence or predictors of progression to myelopathy. [ABSTRACT FROM AUTHOR]

The article presents a study which assesses the feasibility of a modified C2 translaminar screw fixation technique in the general adult population, and to provide safe screw placement. It states that a modified C2 translaminar screw fixation technique was developed to verify feasible screw position. A total of 120 human adult cadaver C2 vertebrae were collected for use in the study. Results show that the ideal safe screw placement is through the thickness of the midportion of the C2 lamina.

Abstract: Background context: Single-level corpectomy and two-level discectomy with anterior cervical plating have been reported to have comparable fusion and complication rates. However, there are few large series that have compared the two for sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification. Purpose: To determine the differences between these two procedures for patients with two-level spondylosis by comparing the pre- and postoperative radiographic data. Study design: Retrospective review of prospectively collected data in an academic institution. Patient sample: Fifty-two with a single-level corpectomy and 45 with a two-level anterior cervical discectomy and fusion (ACDF). Outcome measures: Pre- and postoperative radiographic data for sagittal alignment, cervical lordosis, subsidence, and adjacent-level ossification. Methods: We retrospectively reviewed the lateral cervical radiographs of patients who had a solid fusion after a single-level cervical corpectomy or a two-level ACDF for the treatment of a degenerative cervical spondylosis by a surgeon at an academic institution. The choice of the operation was dependent on the presence or absence of retrovertebral compression. All patients underwent anterior cervical fusion using fibula strut allograft and variable-angle screw-plate fixation. None had had prior cervical spine surgery. Twenty-five were excluded because of inadequate radiographs and follow-up. There were 52 with a single-level corpectomy and 45 with a two-level ACDF. The following were analyzed: 1) sagittal alignment (modified method of Toyama); 2) cervical lordosis measured by Cobb angles of fusion constructs (fusion Cobb) and C2–C7 (C2–C7 Cobb); 3) graft collapse determined by the subsidence of anterior/posterior body height of fused segments (anterior/posterior subsidence) and the cranial/caudal plate-to-disc distances (cranial/caudal subsidence), and the difference between anterior and posterior body height for the fused levels (anteroposterior [AP] difference); and 4) the severity of ossification at two adjacent levels. Results: The mean durations of follow-up were 23.3±6.6 (corpectomy) and 25.7±6.2 (ACDF) months, range 12 to 45 months. There were no significant differences between the two groups in sagittal alignment, cervical lordosis, graft collapse, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis occurred significantly more during the first 6 weeks after surgery (all measurements, p<.0001) than after 6 weeks, with no significant difference between the two groups. Posterior and caudal end plate subsidence significantly progressed after 6 weeks in Group 1 (p=.04, p=.02). The final follow-up Cobb angle positively correlated with preoperative and immediate postoperative Cobb angles (r=0.437, p<.0001; r=0.727, p<.0001), caudal subsidence (r=0.270, p=.008), and the final AP difference (r=0.915, p<.0001) but did not correlate with surgery level, preoperative and final sagittal alignments, anterior/posterior subsidence, and cranial subsidence. Anterior/posterior subsidence was significantly more strongly related with caudal subsidence (r=0.607, p<.0001; r=0.424, p<.0001) than cranial (r=0.277, p=.007; r=0.211, p=.040) but did not correlate with pre- and postoperative fusion Cobb, and preoperative and the last sagittal alignments. Conclusions: Our data suggest that the two procedures yield comparable results in terms of sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis appeared to occur mainly during the first 6 weeks after surgery. Single-level corpectomy and fusion continued to subside at the posterior portion of caudal end plate even after 6 weeks. On the other hand, graft subsidence did not correlate with preoperative and final postoperative sagittal alignments. [Copyright &y& Elsevier]

The article presents a study which evaluates the time-dependent change in range of motion (ROM) among patients after cervical laminoplasty. It notes that cervical laminoplasty is used to treat progressive myelopathy however, it is associated with the loss of flexion and extension ROM. The study examines the time-dependent neck ROM and postoperative neck and arm pain in 23 patients after laminoplasties. The study suggests that loss of cervical ROM is time-dependent and will be stable by 18 months