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Study Design Retrospective cohort. Objective To clarify the sensitivity of C3-C2 spinolaminar line test as a screening tool for the stenosis of C1 space available for the cord (SAC). Methods Spine clinic records from April 2005 to August 2011 were reviewed. The C1 SAC was measured on lateral radiographs, and the relative positions between a C1 posterior arch and the C3-C2 spinolaminar line were examined and considered "positive" when the C1 ring lay ventral to the line. Computed tomography (CT) scans and magnetic resonance imaging (MRI) were utilized to measure precise diameters of C1 and C2 SAC and to check the existence of spinal cord compression. Results Four hundred eighty-seven patients were included in this study. There were 246 men and 241 women, with an average age of 53 years (range: 18 to 86). The mean SAC at C1 on radiographs was 21.2 mm (range: 13.5 to 28.2). Twenty-one patients (4.3%) were positive for the spinolaminar line test; all of these patients had C1 SAC of 19.4 mm or less. Eight patients (1.6%) had C1 SAC smaller than C2 on CT examination; all of these patients had a positive spinolaminar test, with high sensitivity (100%) and specificity (97%). MRI analysis revealed that two of the eight patients with a smaller C1 SAC had spinal cord compression at the C1 level. Conclusion Although spinal cord compression at the level of atlas without instability is a rare condition, the spinolaminar line can be used as a screening of C1 stenosis.

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Study Design Retrospective study. Objective Cervical scoliosis is a rare condition that can arise from various etiologies. Few reports on the surgical management of cervical scoliosis exist. Our objective was to evaluate clinical and radiographic outcomes following surgical management of cervical scoliosis. Methods We evaluated our cervical spine surgical database for patients with cervical scoliosis (Cobb angle > 10 degrees) from 2005 to 2010. Demographic data including age, gender, diagnoses, and primary versus revision surgery was collected. Surgical data including procedure (anterior versus posterior), estimated blood loss (EBL), length of surgery, length of hospitalization, and complications was recorded. Preoperative and postoperative Cobb angle measurements and Neck Disability Index (NDI) scores were recorded. Results Cervical scoliosis was identified in 18 patients. We excluded 5, leaving 5 men and 8 women with an average age of 50.7 (median 52, range 25 to 65). The average follow-up was 40 months (median 36.5, range 5 to 87). An anterior-only approach was used in 6 cases (average 4 levels fused), 5 cases were posterior-only approach (average 8.7 levels fused), and 2 cases were combined anterior-posterior approach. The EBL was an average of 286 mL (median 150, range 50 to 900), the average surgical time was 266 minutes (median 239, range 136 to 508), and the average hospital stay was 2.7 days (median 2, range 1 to 7). Complications occurred in 7 patients, and 2 developed adjacent segment pathology. The average coronal Cobb angle preoperatively was 35.1 degrees (median 31, range 13 to 63) and corrected was 15.7 degrees (median 10.5, range 2 to 59) postoperatively (p < 0.005). The average NDI preoperatively was 24.9 (median 26, range 6 to 37) and was reduced to 17.8 (median 18, range 7 to 30) postoperatively (p < 0.02). Conclusion Surgical management of cervical scoliosis can result in deformity correction and improvement in patient outcomes. Higher rates of complications may be encountered.

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Study Design Retrospective evaluation of prospectively collected data. Objective To compare preoperative and postoperative neck pain following laminoplasty using the Neck Disability Index (NDI). Methods Seventy-two patients undergoing laminoplasty from 2006 to 2009 at a single institution were identified. Thirty-four patients with a minimum 1-year follow-up who completed preoperative, 6-week, and 1-year postoperative NDI questionnaires were enrolled. Demographic data and surgical data including estimated blood loss (EBL), length of surgery, number of laminoplasty levels, complications, and length of hospitalization were collected. Results Mean age was 62 years (range: 34 to 88), mean follow-up was 17 months (range: 12 to 31), and there were 21 men and 13 women. Diagnoses were cervical spondylotic myelopathy (n = 26), ossification of the posterior longitudinal ligament (n = 6), and central cord syndrome (n = 2). Mean EBL was 120 mL (range: 50 to 200), and mean surgical time was 152 minutes (range: 70 to 240). Average number of laminoplasty levels was 3 (range: 1 to 5). The open door technique was used, and 24/34 (71%) did not have laminoplasty at C3 and C7. No intraoperative complications were noted, and average hospital stay was 1.6 days (range: 1 to 7). Significant improvement in NDI total score was noted at 1 year (p < 0.002) and in NDI pain score at 6 weeks (p < 0.028) and 1 year (p < 0.007) postoperatively. Conclusions Patients having laminoplasty experienced significant improvement in NDI pain subscore and NDI total scores at a minimum of 1 year postoperatively.

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STUDY DESIGN: Retrospective review of prospective database. OBJECTIVE: To investigate the long-term results after extension of previous long spine fusions to the sacrum. SUMMARY OF BACKGROUND DATA: Long spine fusions not involving the sacrum may be complicated by distal degeneration and require subsequent extension to the sacrum. The clinical and radiographical outcomes after such revision remain unknown. METHODS: Patients who had extension of a long fusion (≥5 levels with a thoracic level at the cranial end) to the sacrum between 2002 and 2007 at a single institution were analyzed. Oswestry Disability Index and Scoliosis Research Society scores and/or radiographical parameters were assessed at baseline, 6 weeks and 1 year, 2, 3, and/or 5 years postoperatively (PO) and complications were recorded. RESULTS: There were 74 patients with an average age of 49 years (range, 19-76 yr) and average clinical follow-up of 4.5 years (range, 3 mo-10 yr, 82% >2 yr PO). All had degeneration distal to prior fusions and 72% (n = 53) had fixed sagittal imbalance. Sagittal alignment improved at all PO time points from baseline (mean, 78 mm), but worsened between 1 year (mean, 21 mm) and 5 years PO (mean, 44 mm, P = 0.01). Major surgical complications occurred in 30% (n = 22) and there were 17 major reoperations in 15 patients (20%). Significant improvements (P < 0.05) in Oswestry Disability Index and all Scoliosis Research Society domain scores were found at each PO time point with no deterioration from 1 to 5 years PO. Mean outcome scores at 5 years PO were similar in groups with major surgical complications versus without and with major reoperation versus without. CONCLUSION: Extension of long fusions to the sacrum resulted in significant and sustained improvements in Oswestry Disability Index and Scoliosis Research Society scores and alignment during 5 years PO compared with baseline. Major surgical complications occurred in 30% and reoperations were performed in 20%, but outcome scores after treatment were similar to those without complications or reoperations.

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BACKGROUND: While interspinous motion analysis is commonly used to determine the status of an anterior cervical fusion, the accuracy of this technique is unclear. We believed that three questions needed to be answered. What degree of image magnification is ideal? How much motion should be considered "adequate" for making dynamic radiographs? What is the optimal amount of interspinous motion for detecting pseudarthrosis? METHODS: We performed a retrospective study of 125 patients (109 fused segments and 153 pseudarthrotic segments) who had undergone reexploration with confirmation of fusion status. Interspinous motion at each operatively treated level and one superjacent level was measured by two independent investigators twice. Reliabilities of interspinous motion analysis at different magnification rates (25%, 100%, 150%, and 200%) were evaluated for fifty randomly selected segments to determine the optimal magnification, which we used for the remainder of the measurements. Fusion status was also determined on computed tomography (CT) by two other raters. We compared the intraoperative findings with those based on dynamic radiographs (with use of cutoff values of 1 and 2 mm of interspinous motion as the indication of pseudarthrosis) and CT. RESULTS: On radiographs, both 150% and 200% magnification yielded higher interobserver and intraobserver reliabilities compared with 25% and 100% magnification, and the reliabilities at 150% and 200% were similar to each other, so subsequent measurements were made at 150%. The cutoff value of interspinous motion for detecting pseudarthrosis was 0.9 mm as determined with receiver operating characteristic curve analysis. Compared with CT, interspinous motion of ≥ 1 mm showed relatively low sensitivity (79.5%) and negative predictive value (77.1%) and similar specificity (97.0%) and positive predictive value (97.4%). Using interspinous motion of ≥ 2 mm as the cutoff decreased the sensitivity and negative predictive value to 46.6% and 56.8%, respectively. Our evaluation of what constituted adequate dynamic motion for making the radiographs showed that, with use of interspinous motion of ≥ 1 mm as the cutoff for detecting pseudarthrosis, superjacent interspinous motion of ≥ 4 mm increased the sensitivity and negative predictive value (86.3% and 83.4%) compared with those associated with alternative cutoffs of superjacent interspinous motion (≥ 3.5, ≥ 5, and ≥ 6 mm), and the specificity (96.1%) and positive predictive value (96.9%) were reasonable. CONCLUSIONS: Use of interspinous motion of ≥ 1 mm as the cutoff for detection of anterior cervical pseudarthrosis on radiographs magnified 150% and made with superjacent interspinous motion of ≥ 4 mm yielded accuracies comparable with those of CT.

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STUDY DESIGN: Case control study. OBJECTIVE: To evaluate risk factors in patients in 3 groups: those without proximal junctional kyphosis (PJK) (N), with PJK but not requiring revision (P), and then those with PJK requiring revision surgery (S). SUMMARY OF BACKGROUND DATA: It is becoming clear that some patients maintain stable PJK angles, whereas others progress and develop severe PJK necessitating revision surgery. METHODS: A total of 206 patients at a single institution from 2002 to 2007 with adult scoliosis with 2-year minimum follow-up (average 3.5 yr) were analyzed. Inclusion criteria were age more than 18 years and primary fusions greater than 5 levels from any thoracic upper instrumented vertebra to any lower instrumented vertebrae. Revisions were excluded. Radiographical assessment included Cobb measurements in the coronal/sagittal plane and measurements of the PJK angle at postoperative time points: 1 to 2 months, 2 years, and final follow-up. PJK was defined as an angle greater than 10°. RESULTS: The prevalence of PJK was 34%. The average age in N was 49.9 vs. 51.3 years in P and 60.1 years in S. Sex, body mass index, and smoking status were not significantly different between groups. Fusions extending to the pelvis were 74%, 85%, and 91% of the cases in groups N, P, and S. Instrumentation type was significantly different between groups N and S, with a higher number of upper instrumented vertebra hooks in group N. Radiographical parameters demonstrated a higher postoperative lumbar lordosis and a larger sagittal balance change, with surgery in those with PJK requiring revision surgery. Scoliosis Research Society postoperative pain scores were inferior in group N vs. P and S, and Oswestry Disability Index scores were similar between all groups. CONCLUSION: Patients with PJK requiring revision were older, had higher postoperative lumbar lordosis, and larger sagittal balance corrections than patients without PJK. Based on these data, it seems as though older patients with large corrections in their lumbar lordosis and sagittal balance were at risk for developing PJK, requiring revision surgery. LEVEL OF EVIDENCE: 3.

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BACKGROUND: Surgical site infection remains a complication of spine surgery despite routine use of prophylactic antibiotics. Retrospective clinical studies of intrawound vancomycin use have documented a decreased prevalence of surgical site infection after spine surgery. The purpose of the present study was to assess the efficacy of intrawound vancomycin powder in terms of eradicating a known bacterial surgical site contamination in a rabbit spine surgery model. METHODS: Twenty New Zealand White rabbits underwent lumbar partial laminectomy and wire implantation. The surgical sites were inoculated, prior to closure, by injecting 100 µL of cefazolin-sensitive and vancomycin-sensitive Staphylococcus aureus (S. aureus) (1 × 108 colony-forming units [CFU]/mL) into the wound. Preoperative cefazolin was administered to all rabbits, and vancomycin powder (100 mg) was placed into the wound of ten rabbits prior to closure. The rabbits were killed on postoperative day four, and tissue and wire samples were obtained for bacteriologic assessment. An independent samples t test was used to assess mean group differences, and a Fisher exact test was used to assess differences in categorical variables. RESULTS: The vancomycin-treated and the control rabbits were similar in weight (mean [and standard deviation], 4.1 ± 0.5 kg and 4.0 ± 0.4 kg, respectively; p = 0.60) and sex distribution and had similar durations of surgery (21.7 ± 7.7 minutes and 16.9 ± 6.7 minutes; p = 0.15). The bacterial cultures of the surgical site tissues were negative for all ten vancomycin-treated rabbits and positive for all ten control rabbits (p < 0.0001). Bacterial growth occurred in thirty-nine of forty samples from the control group but in zero of forty samples from the vancomycin group (p < 0.0001). All blood and liver samples were sterile. No rabbit had evidence of sepsis or vancomycin toxicity. Gross examination of the surgical sites showed no differences between the groups. CONCLUSIONS: In a rabbit spine-infection model, intrawound vancomycin powder in combination with preoperative cefazolin eliminated S. aureus surgical site contamination. All rabbits that were managed with only prophylactic cefazolin had persistent S. aureus contamination. CLINICAL RELEVANCE: This animal study supports the findings in prior clinical reports that intrawound vancomycin powder helps reduce the risk of surgical site infections.

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STUDY DESIGN: Retrospective. OBJECTIVES: The authors hypothesized that cervical lordosis (CL) would decrease with aging and increasing degeneration. SUMMARY OF BACKGROUND DATA: It is theorized that with age and degeneration, the cervical spine loses lordosis and becomes progressively more kyphotic; however, no studies support these conclusions in patients with various spinal deformities. METHODS: The authors performed a radiographic analysis of asymptomatic adults (referring to their cervical spine) of varying ages, with differing forms of spinal deformity to the thoracic/lumbar spine to see how cervical lordosis changes with increasing age. A total of 104 total spine EOS X-rays of adult (aged >18 years) spinal deformity patients without documented neck pain, prior neck surgery, or cervical deformity were reviewed. The researchers only reviewed EOS X-rays because they allow complete visualization from occiput to feet. Cervical lordosis, standard Cobb measurements, sagittal balance parameters, and cervical degeneration were quantified radiographically by the method previously described by Gore et al. Statistical analysis was performed with 1-way analysis of variance to compare significant differences between groups aged <40, 40-60 and >60 years as well as changes in sagittal balance. A p-value < .05 was considered significant. RESULTS: Average CL actually increased with increasing age (10.3 ± 14.7, 15.4 ± 15.1, and 23.3 ± 1.6.7 for age < 40, 40-60, and > 60 years, respectively; p < .05). Average cervical degeneration score increased at all disc space levels from C2 to C7 across age groups (0.7 ± 1.2, 9.9 ± 69, and 16.3 ± 8.9 for age <40, 40-60, and >60 years, respectively; p < .01), with the highest degeneration at the C5-6 and C6-7 disc spaces (3.7 ± 3.3 and 3.2 ± 2.9, respectively; p < .01). This increase did not correlate with the increase in CL seen with aging (r = 0.02; p = .84). CONCLUSIONS: Cervical lordosis increased with aging in adult spinal deformity patients. There was no relationship between cervical degeneration and lordosis despite the strong relationship seen between increasing CL in older age groups.