Magnetic Resonance Imaging Is Inadequate to Assess Cervical Sagittal Alignment Parameters.

STUDY DESIGN: Retrospective radiographic study. OBJECTIVE: To evaluate cervical sagittal alignment measurement reliability and correlation between upright radiographs and magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Cervical sagittal alignment (CSA) helps determine the surgical technique employed to treat cervical spondylotic myelopathy. Traditionally, upright lateral radiographs are used to measure CSA, but obtaining adequate imaging can be challenging. Utilizing MRI to evaluate sagittal parameters has been explored; however, the impact of positional change on these parameters has not been determined. METHODS: One hundred seventeen adult patients were identified who underwent laminoplasty or laminectomy and fusion for cervical spondylotic myelopathy from 2017 to 2019. Two clinicians independently measured the C2-C7 sagittal angle, C2-C7 sagittal vertical axis (SVA), and the T1 tilt. Interobserver and intraobserver reliability were assessed by intraclass correlation coefficient. RESULTS: Intraobserver and interobserver reliabilities were highly correlated, with correlations greater than 0.85 across all permutations; intraclass correlation coefficients were highest with MRI measurements. The C2-C7 sagittal angle was highly correlated between x-ray and MRI at 0.76 with no significant difference ( P =0.46). There was a weaker correlation with regard to C2-C7 SVA (0.48) and T1 tilt (0.62) with significant differences observed in the mean values between the 2 modalities ( P <0.01). CONCLUSIONS: The C2-C7 sagittal angle is highly correlated and not significantly different between upright x-ray and supine MRIs. However, cervical SVA and T1 tilt change with patient position. Since MRI does not accurately reflect the CSA in the upright position, upright lateral radiographs should be obtained to assess global sagittal alignment when planning a posterior-based cervical procedure.

Laminoplasty-an underutilized procedure for cervical spondylotic myelopathy.

BACKGROUND CONTENT: Cervical laminoplasty (LP) and laminectomy and fusion (LF) are commonly used surgical techniques for cervical spondylotic myelopathy (CSM). Several recent studies have demonstrated superior perioperative metrics and decreased overall costs with LP, yet LF is performed far more often in the United States. PURPOSE: To determine the percentage of patients with CSM who are radiographically candidates for LP. STUDY DESIGN: Retrospective comparative cohort study. PATIENT SAMPLE: Patients >18 years old who underwent LF or LP for CSM at 2 large academic institutions from 2017 to 2019. OUTCOME MEASURES: Candidacy for LP based on radiographic criteria. METHODS: Radiographs were assessed by 2 spine surgeons not involved in the care of the patients to determine the C2-C7 Cobb angle and the presence and extent of cervical instability. Patients with kyphosis >13°, > 3.5 mm of listhesis on static imaging, or > 2.5 mm of motion on flexion-extension or standing-supine films were not considered candidates for LP. Intraclass coefficient (ICC) was calculated to assess the interobserver reliability of angular measurements and the presence of instability. The percentage of patients for whom LP was contraindicated was calculated. RESULTS: One hundred eight patients underwent LF while 142 underwent LP. Of the 108 patients who underwent LF, 79.6% were radiographically deemed candidates for LP, as were all 142 patients who underwent LP. The ICC for C2-C7 alignment was 0.90; there was 97% agreement with respect to the presence of instability. CONCLUSIONS: In 250 patients with CSM, 228 (91.2%) were radiographically candidates for LP. These data suggest that LP may be an underutilized procedure for the treatment for CSM.

Laminoplasty versus laminectomy and fusion for cervical spondylotic myelopathy: a cost analysis.

BACKGROUND CONTEXT: Laminectomy with fusion (LF) and laminoplasty (LP) are commonly used to treat cervical spondylotic myelopathy (CSM). The decision regarding which procedure to perform is largely a matter of surgeon's preference, while financial implications are rarely considered. PURPOSE: We aimed to better understand the financial considerations of LF compared to LP in the treatment of CSM. STUDY DESIGN: Retrospective comparative study. PATIENT SAMPLE: Adult patients, 18 years of age or older, who had undergone LF or LP for CSM from 2017 to 2019 at 2 large academic centers were included. Patients who had undergone previous cervical spine surgery or procedures that extended above C2 or below T2 were excluded. OUTCOME MEASURES: The primary outcome was defined as the total cost of the procedure, which was calculated as the sum of the implant and non-implant supply costs. METHODS: Patient demographics, surgical parameters, including estimated blood loss and operative time, and length of stay were collected. Operating room material - both implant and non-implant - cost data was also obtained. Variables were analyzed individually as well as after adjustment based on the number of operative levels involved. Statistical analysis was performed using either Student t test with unequal variance or Wilcoxon rank sum test for continuous variables and chi-squared analysis for categorical variables. RESULTS: Two hundred fifty patients were identified who met inclusion criteria. There was no statistical difference in the mean age at time of surgery (p=.25), gender distribution (p=.33), or re-operation rate between the LF and LP groups (p=.39). Overall, operative time was similar between the LF (165.7 ± 61.9 min) and LP (173.8 ± 58.2 min) groups (p=.29), but the LP cohort had a shorter length of stay at 3.8 ± 2.7 days compared to the LF cohort at 4.8 ± 3.7 days. Implant costs in the LF group were significantly more at $6,204.94 ± $1426.41 compared to LP implant costs at $1994.39 ± $643.09. Mean total costs of LP were significantly less at $2,859.08 ± $784.19 compared to LF total costs of $6,983.16 ± $1,589.17. Furthermore, when adjusted for the number of operative levels, LP remained significantly less costly at $766.12 ± $213.64 per level while LF cost $1,789.05 ± $486.66 per operative level. Additional subgroup analysis limiting the cohorts to patients with either three or four involved vertebral levels demonstrated nearly identical cost savings with LP as compared to LF. CONCLUSIONS: This study demonstrates that LF is on average at least 2.4 times the total operative supply cost of LP and at least 2.3 times the operative supply cost of LP when adjusted for the number of operative levels. In patients deemed appropriate for either LP or LF, these data may be incorporated into decision-making for the treatment of CSM.

Post-operative hyperglycemia and its association with surgical site infection after instrumented spinal fusion.

OBJECTIVE: To evaluate the correlation between postoperative hyperglycemia and surgical site infection among patients who underwent primary instrumented spinal fusion surgery. PATIENTS AND METHODS: We collected data on all eligible patients treated at our institution over the course of 2005-2017. We defined serum hyperglycemia using a primary threshold of serum glucose ≥140 mg/dL and used ≥115 mg/dL as a secondary test. We used logistic regression techniques to evaluate unadjusted results for serum hyperglycemia on revision surgeries for infection, followed by sequential adjustment for sociodemographic and procedural characteristics. RESULTS: We included 3664 patients. Surgical site infections occurred in 4%. Post-operative hyperglycemia was significantly associated with a higher rate of revision surgery for infection (p = 0.02). Following adjusted analysis, hyperglycemia remained a statistically significant predictor for revision surgery due to infection (OR 2.19; 95 % CI 1.13, 4.25). Similar results were evident when using the lower threshold of ≥115 mg/dL (OR 2.36; 95 % CI 1.06, 5.23). CONCLUSIONS: This study highlights the importance of measuring serum glucose after spinal fusion and the need for heightened surveillance and/or treatment in those who exhibit postoperative hyperglycemia. In this context, it could be advantageous to use a lower threshold for hyperglycemia (115 mg/dL) in order to trigger interventions for glycemic control.

Incidental Durotomy Is Associated With Increased Risk of Delirium in Patients Aged 65 and Older.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate the impact of incidental durotomy during spine surgery on the development of delirium in patients aged 65 and older. SUMMARY OF BACKGROUND DATA: Delirium after spine surgery has been shown to increase the risk of adverse events, including morbidity and readmissions. Durotomy has previously been postulated to influence the risk of delirium, but this has not been explored in patients 65 and older, the demographic at greatest risk of developing delirium. METHODS: We obtained clinical data on 766 patients, including 182 with incidental durotomy, from the Partners healthcare registry (2012-2019). Patients had their medical records abstracted and age, biologic sex, body mass index, smoking status, preoperative diagnosis, use of a fusion-based procedure, and number of comorbidities were recorded. Our primary outcome was the development of delirium. Our primary predictor was incidental durotomy. We used logistic regression techniques to adjust for sociodemographic and clinical confounders. We performed propensity score matching as a sensitivity test. We hypothesized that elderly patients would be at increased risk of delirium following durotomy. RESULTS: Delirium was identified in 142 patients (19%). Among patients with an incidental durotomy, 26% were diagnosed with delirium. The incidence of delirium was 16% in the control group. Following adjusted analysis, the likelihood of delirium was significantly greater in patients with a durotomy (odds ratio [OR] 1.91; 95% confidence interval [CI] 1.27, 2.88). After propensity score matching, durotomy remained significantly associated with delirium in multivariable adjusted analyses (OR 1.90; 95% CI 1.07, 3.39). CONCLUSION: This investigation is among the first to specifically evaluate an association between durotomy and delirium in elderly patients undergoing spine surgery. The increased association between durotomy and delirium in this cohort should prompt increased surveillance and interventions designed to minimize the potential for cognitive deterioration or impairment during postoperative management of a durotomy. LEVEL OF EVIDENCE: 3.

The Impact of Vancomycin and Cefazolin as Standard Preoperative Antibiotic Prophylaxis on Surgical Site Infections Following Instrumented Spinal Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess whether administration of prophylactic vancomycin, in addition to cefazolin decreased revision surgeries for postoperative infection (SSI) as well as the need for revisions overall. SUMMARY OF BACKGROUND DATA: In 2010 our institution implemented an antibiotic prophylaxis regimen consisting of intravenous vancomycin and cefazolin that applied to all patients receiving surgical implants. The impact of this change in prophylactic antibiotic regimen on SSIs following instrumented spinal fusions remains unknown. METHODS: We conducted a prepost analysis evaluating the effect of the change in antibiotic prophylaxis on SSIs following instrumented spinal fusions. We collected data on all eligible patients over the course of 2005 to 2009 and 2011 to 2015. We used logistic regression techniques to evaluate unadjusted results for the prophylactic antibiotic protocol on all revision surgeries, as well as those for SSI, followed by sequential adjustments for sociodemographic factors and surgical characteristics. RESULTS: Revision surgeries performed for a diagnosis of infection were reduced from a rate of 4% (n = 57) in the period 2005 to 2009 to 2% (n = 44) over 2011 to 2015 (P < 0.001). At the same time, the incidence of revision surgeries for any cause was also reduced (14% in 2005-2009 vs. 9% in 2011-2015; P < 0.001). In adjusted analysis, the odds of a revision procedure for SSI were reduced by 50% following introduction of the protocol (OR 0.50; 95% CI 0.33, 0.76). No significant difference in the organisms responsible for SSI was identified between 2005 and 2009 and 2011 and 2015 (P = 0.22). CONCLUSION: This natural experiment has shown some utility for a preoperative prophylactic antibiotic regimen of vancomycin and cefazolin, including meaningful reductions in revision procedures performed for SSI. This is the first effort we are aware of to consider a uniform institutional protocol that employs the use of intravenous vancomycin and cefazolin as prophylactic agents. LEVEL OF EVIDENCE: 2.