Study Design. Retrospective case-control study. Objective. To determine incidence and timing of mortality following surgery for spinal epidural abscess (SEA), identify risk factors for mortality, and identify complications associated with mortality. Summary of Background Data. SEA is a serious condition with potentially devastating sequelae. There is a paucity of literature characterizing mortality following surgery for SEA. Methods. The National Surgical Quality Improvement Program (NSQIP) database was used. Patients with a diagnosis of SEA were included. A Cox proportional hazards model identified independent risk factors for 30-day mortality. A predictive model for mortality was created. Multivariate models identified postoperative complications associated with mortality. Results. There were 1094 patients included, with 40 cases of mortality (3.7%), the majority of which occurred within 2 weeks postoperatively (70%). Independent risk factors for 30-day mortality were age>60 years (hazard ratio [HR]: 2.147, P = 0.027), diabetes (HR: 2.242, P = 0.015), respiratory comorbidities (HR: 2.416, P = 0.037), renal comorbidities (HR: 2.556, P = 0.022), disseminated cancer (HR: 5.219, P = 0.001), and preoperative thrombocytopenia (HR: 3.276, P = 0.001). A predictive algorithm predicts a 0.3% mortality for zero risk factors up to 37.5% for 4 or more risk factors. A ROC area under curve (AUC) was 0.761, signifying a fair predictor (95% CI: 0.683–0.839, P < 0.001). Cardiac arrest (adjusted odds ratio [aOR]: 72.240, 95% confidence interval [CI]: 27.8–187.721, P < 0.001), septic shock (aOR: 15.382, 95% CI: 7.604–31.115, P < 0.001), and pneumonia (aOR: 2.84, 95% CI: 1.109–7.275, P = 0.03) were independently associated with mortality. Conclusion. The 30-day mortality rate following surgery for SEA was 3.7%. Of the mortalities that occurred within 30 days of surgery, the majority occurred within 2 weeks. Independent risk factors for mortality included older age, diabetes, hypertension, respiratory comorbidities, renal comorbidities, metastatic cancer, and thrombocytopenia. Risk for mortality ranged from 0.3% to 37.5% based on number of risk factors. Septic shock, cardiac arrest, and pneumonia were associated with mortality. Level of Evidence: 3

OBJECTIVE There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence–lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5–S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Study Design:Retrospective radiographic study.Objective:The optimal radiographic modality for assessing cervical foraminal stenosis is unclear. Determination on conventional axial cuts is made difficult due in part to the complex, oblique orientation of the cervical neuroforamen. The utility of 3-dimensonal (3D) computed tomography (CT) reconstruction in improving neuroforaminal assessment is not well understood. The objective of this study is to determine inter-rater variability in grading cervical foraminal stenosis using 3 different CT imaging modalities: 3D CT surface reconstructions (3DSR), 2D sagittal oblique multiplanar reformations (2D-SOMPR), and conventional 2D axial CT imaging.Methods:Pretreatment CT scans of 25 patients undergoing surgery for cervical spondylotic radiculopathy were analyzed at 2 levels: C5-C6 and C6-C7. Simple interrater agreement and kappa-Fleiss coefficients were calculated for each imaging modality and stenosis grade. Image reviewers (attending spine surgeon, attending neuroradiologist, spine fellow) interpreted each CT scan in 3 different formats: axial, 2D-SOMPR, and 3DSR. Four cervical foramina at 2 spinal levels were graded as normal (no stenosis), mild (≤25% stenosis), moderate (25%-50% stenosis), or severe (>50% stenosis).Results:Across all imaging modalities, interrater reliability was fair when grading foraminal stenosis (κ < 0.4). Agreement was lowest for the axial images (κ = 0.119) and highest for the 3D CT reconstructions (κ = 0.334). 2D-SOMPR images also led to improved interrater reliability when compared with axial images (κ = 0.255).Conclusion:Grading cervical foraminal stenosis using conventional axial CT imaging is difficult with low interrater reliability. CT modalities that provide a circumferential view of the cervical foramen, such as 2D-SOMPR and 3D CT reconstruction, had higher rates of interobserver reliability in grading foraminal stenosis than conventional axial cuts, with 3D having the highest. As these 3D reconstructions can be obtained at no additional cost or radiation exposure over a conventional CT scan, and because they can provide useful information in determining levels being considered for surgical decompression, we recommend they be utilized when evaluating cervical foramina.

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