Jamal McClendon

Techniques for operative correction of proximal junctional kyphosis of the upper thoracic spine.

Study Design. Retrospective study of a consecutive series of patients treated for proximal junctional kyphosis (PJK) of the upper thoracic and cervicothoracic spine. Objective. To discuss corrective techniques for the management of symptomatic kyphosis at the junction of fused and mobile segments of the upper thoracic and cervicothoracic spine in patients who complain of pain, neurological deficit, ambulatory difficulty, and/or social isolation. Summary of Background Data. PJK is an unfortunately common, but important, complication seen in long instrumented fusions to the upper thoracic and cervicothoracic spine. Although often asymptomatic, its incidence and prevalence warrant a discussion on treatment options for symptomatic patients. Methods. After the institutional review board confirmed approval, we retrospectively analyzed patients who received treatment of PJK from 2003 to 2009. Segmental instrumentation and intraoperative neurophysiological monitoring were used in all patients. Data acquisition was performed by reviewing electronic medical records and radiographs. Inclusion criteria were patients who underwent surgical correction of PJK of the cervicothoracic and upper thoracic spine and had more than 2-year follow-up. Preoperative lumbar lordosis, preoperative thoracic kyphosis, pre- and postoperative sagittal balance, and sagittal proximal junctional Cobb angle were obtained. All corrective procedures were performed in 2 stages, each patient receiving cervical traction between cases. Results. Inclusion criteria were met in 7 patients (5 women and 2 men), with mean age of 55 years (range, 18–80 years). Six patients received multilevel Smith-Petersen osteotomies, with 2 patients receiving rib osteotomies, and 1 patient received a vertebral column resection. The mean preoperative and postoperative proximal junctional Cobb angles were 45° (range, 14°–89.7°) and 14° (range, 3.0°–38.0°), respectively. The mean degree of correction was 31° (range, 11°–79.2°). All patients had maintained or improved sagittal balance. No patient sustained a temporary or permanent neurological deficit after correction related to surgery. All patients had 2-year follow-up, and there were no mortalities. Conclusion. For a selected cohort of patients who develop PJK of the upper thoracic and cervicothoracic spine, osteotomies, cervical traction, and intraoperative manual reduction provide a significant improvement of proximal junctional Cobb angles. To our knowledge, this is the first study to address treatment for symptomatic patients with this condition.

Development of venous thromboembolism (VTE) in patients undergoing surgery for brain tumors: Results from a single center over a 10 year period

Patients who undergo craniotomy for brain neoplasms have a high risk of developing venous thromboembolism (VTE), including deep vein thromboses (DVT) and pulmonary emboli (PE). The reasons for this correlation are not fully understood. This retrospective, single-center review aimed to determine the risk factors for VTE in patients who underwent neurosurgical resection of brain tumors at Northwestern University from 1999 to 2010. Our cohort included 1148 patients, 158 (13.7%) of whom were diagnosed with DVT and 38 (3.3%) of whom were diagnosed with PE. A variety of clinical factors were studied to determine predictors of VTE, including sex, ethnicity, medical co-morbidities, surgical positioning, length of hospital stay, tumor location, and tumor histology. Use of post-operative anticoagulants and hemorrhagic complications were also investigated. A prior history of VTE was found to be highly predictive of post-operative DVT (odds ratio [OR]=7.6, p=0.01), as was the patients sex (OR=14.2, p<0.001), ethnicity (OR=0.5, p=0.04), post-operative intensive care unit days (OR=0.2, p=0.003), and tumor histology (OR=-0.16, p=0.01). Contrary to reports in the literature, the data collected did not indicate that the administration of post-operative medical prophylaxis for VTE was significant in preventing their formation (OR=-0.14, p=0.76). Hemorrhagic complications were low (2.2%) and resultant neurologic deficit was lower still (0.7%). The study indicates that patients with high-grade primary brain tumors and metastatic lesions should receive aggressive preventative measures in the post-operative period.

The Impact of Body Mass Index on Hospital Stay and Complications After Spinal Fusion

BACKGROUND Obesity is a dominant public health concern and risk factor for disability, with few studies examining its impact in spinal surgery. Patients with a higher body mass index (BMI) have lower functional status, increased pain, and worse physical condition than those with ideal weight. OBJECTIVE To determine associations between BMI categories on adverse patient outcomes after long-segment spinal fusions. METHODS Consecutive, open, elective fusions (interbody and/or posterolateral arthrodesis) of more than 5 levels from 2007 to 2010 were retrospectively analyzed with follow-up of more than 1 year. Bivariate analyses examined outcome variables based on BMI categories. Linear regression analysis evaluated BMI, hospital stay, and complications at 1 and 2 years, controlling for confounders. Mean and median follow-up lengths were 2.1 and 2.0 years, respectively. RESULTS A total of 189 surgeries on 112 patients, with a mean age of 59.5 years and a mean BMI of 29.8 kg/m, were analyzed. Morbidly obese patients had longer hospitalizations, worse Oswestry Disability Index (ODI), and more complications at 1 and 2 years than ideal weight patients. Multivariate linear regression modeling revealed sex, cardiac medications, cerebrospinal fluid leak, and BMI category of ideal vs nonideal influenced hospitalization length. Multivariate analysis showed BMI greater than 30 kg/m, preoperative ODI, and pedicle subtraction osteotomy influenced all complications at 1 year. Mean complications at 2 years for the morbidly obese were 3 times more than those underweight and 8 times more than those with ideal weight. Controlling for age, sex, and length of stay, obese and morbidly obese patients had more complications at 2 years; morbidly obese patients had a worse 2-year ODI. CONCLUSION BMI is an independent predictor of hospitalization length and all complications at 1 and 2 years in patients receiving long-segment fusions.

Spontaneous Cervical and Cerebral Arterial Dissections Diagnosis and Management

Arterial dissections of head and neck arteries were first identified pathologically in the 1950s, but not until the 1970s and the 1980s did they begin to be widely recognized as a clinical entity. Carotid and vertebral artery dissections account for only 2% of all ischemic strokes, but they account for approximately 20% of thromboembolic strokes in patients younger than 45 years. The cause of supra-aortic dissections can be either spontaneous or traumatic. This article addresses spontaneous cervical and cerebral artery dissections.

Comprehensive assessment of prophylactic preoperative inferior vena cava filters for major spinal reconstruction in adults

Study Design. A retrospective data analysis. Objective. To report a comprehensive assessment of preoperative prophylactic inferior vena cava (IVC) filter placement in spine surgery. Summary of Background Data. Venous thromboembolism (VTE) is a serious complication after major spinal reconstructive surgery in adults. Specifically, pulmonary embolism (PE) can result in significant morbidity and mortality, and it has been reported in up to 13% of patients. Prophylactic IVC filter placement was initiated for all “high-risk” spinal surgery patients after a pilot study demonstrated decreased VTE-related morbidity and mortality. Methods. After institutional review board approval, the medical records of all patients receiving an IVC filter at a single institution from 2000 to 2007 were reviewed. Age, sex, surgical approach, postoperative deep vein thrombosis (DVT), postoperative superficial thrombus, presence of pulmonary or paradoxical embolus, mortality, and IVC filter complications were all evaluated. Indications for IVC filter placement included history of DVT or PE, malignancy, hypercoagulability, prolonged immobilization, staged procedures of longer than 5 segment levels, combined anterior-posterior approaches, iliocaval manipulation during exposure, and anesthetic time of more than 8 hours. Descriptive statistics were used for the analysis of patient characteristics. Nonparametric frequency statistics (odds ratios [OR], &khgr;2) were used for analysis of main outcomes. Results. A total of 219 patients (150 women, 69 men) with a mean age of 58.8 (range, 17–86) years, were analyzed. There were 2 complications from IVC filter placement (66 Greenfield filters; 157 retrievable filters). The incidence of lower extremity DVT was 18.7% (41/219) in 36 patients. PE incidence was 3.7% (8/219 patients), and the paradoxical embolus rate was 0.5% (1 patient). Prophylactic IVC filter use reduced the odds of developing a pulmonary embolus (OR = 3.7, P < 0.05) compared with population controls. Patients receiving Greenfield filters had significantly higher VTE incidence than those receiving retrievable filters (OR = 2.8, P = 0.008). Anesthesia duration of more than 8 hours significantly increases VTE incidence (P = 0.029). No statistical significance (P < 0.05) was noted with combined anterior-posterior approach (118 patients) versus posterior-only approach (101 patients) and the incidence of DVT (24/118, 20.3% for former; 17/101, 16.8% for latter). There were a total of 14 deaths; none related to PE or paradoxical embolism during an 8-year period. Mean and median follow-up was 2.8 and 2.4 years, respectively, with 126 achieving 2 or more years of follow-up. Conclusion. VTE-related morbidity and mortality have heightened the awareness within the spine community to the perioperative management of patients undergoing major spinal reconstruction. Prophylactic IVC filter placement significantly lowers VTE-related events, including PE development, than population controls.

Redefining global spinal balance: Normative values of cranial center of mass from a prospective cohort of asymptomatic individuals

Study Design. Prospective radiographical analysis of cranial center of mass (CCOM), C2, and C7 plumb lines in young and elderly asymptomatic individuals. Objective. To establish a normal range for craniosagittal balance for both young and elderly asymptomatic individuals. Summary of Background Data. Global sagittal balance must account for the position of the head in relation to the spine and pelvis. The C7 plumb line defines thoracolumbar sagittal balance and has been shown to have significant impact on patient outcomes. However, the C7 plumb line fails to take into consideration the position of the head in relation to the pelvis. Methods. A total of 100 asymptomatic 20- to 40-year-old patients and 100 asymptomatic 60- to 80-year-old patients were enrolled. Standing plain radiographs of 14 × 36 in were obtained. CCOM, C2, and C7 plumb lines were drawn and measured from the superoposterior endplate of S1. Results. A total of 78 asymptomatic 20- to 40-year-old patients and 62 asymptomatic 60- to 80-year-old patients had adequate radiographs. The mean plumb line values in the 20- to 40-year-old patients and 60- to 80-year-old patients, respectively, were as follows; CCOM 9.0 mm (SD, 31.5 mm) and 41.2 mm (SD, 35.7 mm); C2 −2.7 mm (SD, 32.7 mm) and 32.1 mm (SD, 33.6 mm); and C7 −16.4 mm (SD, 31.5 mm) and 10.6 mm (SD, 27.8 mm). One-way analysis of variance and Student t tests confirmed that these mean plumb line values were significantly different between young and elderly patients (P < 0.001). The change at each level over time was highly correlated with the other levels (r > 0.97; P < 0.001) as did the degree of change between groups (r > 0.90, P < 0.001). Conclusion. Spinopelvic alignment in conjunction with CCOM has increased our understanding of spinal balance by including the head and may better represent true global spinal balance. CCOM is an easily measured parameter by using the nasion-inion technique.

Utility of Readmission Rates as a Quality of Care Measure and Predictors of Readmission Within 30 Days After Spinal Surgery: a Single-Center, Multivariate Analysis.

Study Design. A retrospective review Objective. The aim of this study was to establish clinically relevant readmission rates that permit accurate comparisons, improve risk‐stratification, and direct efforts to minimize readmissions. Summary of Background Data. The 30‐day hospital readmission rate is a quality of care measure that is now being used to compare hospitals in a publicly available manner. Methods. Records from 1187 consecutive spinal surgeries at Northwestern Memorial Hospital in 2010 were retrospectively reviewed and data were collected that described the patient, surgical procedure, hospital course, complications, and readmissions. The primary outcome of interest was readmission to the hospital within 30 days. Potential risk factors were examined for association with the outcome first via bivariate analysis, with significant predictors further examined by a multivariable model. Identified readmissions were independently reviewed by attending spinal neurosurgeons not involved with the cases to determine whether the readmissions were procedure related or procedure unrelated with respect to accepted criteria. Results. The overall readmission rate was 6.1%. Of these readmissions, 37.5% were deemed procedure related upon attending review, leading to a procedure‐related readmission rate of 2.3%. Upon multivariate analysis, only 3 variables were found to be significant predictors of readmission: 2 or more patient comorbidities [odds ratio (OR) 3.72, 95% confidence interval (95% CI) 1.62–8.56], an admission to the ICU (OR 2.68, 95% CI 1.45–4.95), and each additional spinal level involved (OR 1.11, 95% CI 1.02–1.21). Conclusions. Our study suggests that predictors for all‐cause 30‐day readmission following spinal procedures include number of spinal levels performed during the surgery, number of patient comorbidities present at the time of surgery, and whether the admission required an ICU stay. Future work should focus on developing best practices to modify medical risk factors and comorbidities that have the potential to decrease 30‐day readmission rates. Level of Evidence: 3

Predicting major adverse cardiac events in spine fusion patients: Is the revised cardiac risk index sufficient?

Study Design. Observational cohort study. Objective. To determine the accuracy of the Revised Cardiac Risk Index (RCRI) in predicting major adverse cardiac events in patients undergoing spine fusion surgery of 3 levels or more. Summary of Background Data. Preoperative cardiac testing is extensively guided by the RCRI, which was developed and validated in thoracic, abdominal, and orthopedic surgical patients. Because multilevel spine fusion surgery is often associated with major transfusion, we hypothesize that the RCRI may not accurately characterize the risk of cardiovascular morbidity in these patients. Methods. After institutional review board approval, perioperative data were collected from 547 patients who underwent 3 or more levels of spinal fusion with instrumentation. Postoperative cardiac morbidity was defined as any combination of the following: arrhythmia requiring medical treatment, myocardial infarction (either by electrocardiographic changes or troponin elevation), or the occurrence of demand ischemia. The surgical complexity was categorized as anterior surgery only, posterior cervical and/or thoracic fusion, posterior lumbar fusion, or any surgery that included transpedicular osteotomies. Logistic regression analysis was performed to determine RCRI performance. Results. The RCRI performed no better than chance (area under the curve = 0.54) in identifying the 49 patients (9%) who experienced cardiac morbidity. Conclusion. The RCRI did not predict cardiac morbidity in our patients undergoing major spine fusion surgery, despite being extensively validated in low-risk noncardiac surgical patients. Preoperative testing and optimization decisions, previously based on the RCRI, may need to be revised to include more frequent functional cardiac imaging and more aggressive implementation of pharmacologic modalities that may mitigate cardiac morbidity, similar to the preoperative evaluation for major vascular surgery. Level of Evidence: 3

Management of ossification of the posterior longitudinal ligament of the thoracic spine

The management of thoracic ossification of the posterior longitudinal ligament has been studied by many spinal surgeons. Indications for operative intervention include progressive radiculopathy, myelopathy, and neurological deterioration. The ideal surgery for decompression remains highly debatable as various methods of surgical treatment of ossification of the posterior longitudinal ligament have been devised. Although numerous modifications to the 3 main approaches have been identified (anterior, posterior, or lateral), the indication for each depends on the nature of compression, the morphology of the lesion, the level of the compression, the structural alignment of the spine, and the neurological status of the patient. The authors discuss treatment techniques for thoracic ossification of the posterior longitudinal ligament, cite case examples from a single institution, and review the literature.

Baseline patient-reported outcomes correlate weakly with radiographic parameters a multicenter, prospective NIH adult symptomatic lumbar scoliosis study of 286 patients

Study Design. Prospective, cross-sectional study. Objective. The aim of the study was to determine which radiographic parameters drive patient-reported outcomes (PROs) in primary presentation adult symptomatic lumbar scoliosis (ASLS). Summary of Background Data. Previous literature suggests correlations between PROs and sagittal plane deformity (sagittal vertical axis [SVA], pelvic incidence-lumbar lordosis [PI-LL] mismatch, pelvic tilt [PT]). Prior work included revision and primary adult spinal deformity patients. The present study addresses only primary presentation ASLS. Methods. Prospective baseline data were analyzed on 286 patients enrolled in an NIH RO1 clinical trial by nine centers from 2010 to 2014. Inclusion criteria: 40 to 80 years old, lumbar Cobb (LC) 30° or higher and Scoliosis Research Society-23 score 4.0 or less in Pain, Function or Self-Image domains, or Oswestry Disability Index (ODI) 20 or higher. Patients were primary presentation (no prior spinal deformity surgery) and had complete baseline data: standing coronal/sagittal 36” radiographs and PROs (ODI, Scoliosis Research Society-23, Short Form-12). Correlation coefficients were calculated to evaluate relations between radiographic parameters and PROs for the study population and a subset of patients with ODI 40 or higher. Analysis of variance was used to identify differences in PROs for radiographic modifier groups. Results. Mean age was 60.3 years. Mean spinopelvic parameters were: LL = −39.2°; SVA = 3.1 cm; sacral slope = 32.5°; PT = 23.9°; PI-LL mismatch = 16.8°. Only weak correlations (0.2–0.4) were identified between population sacral slope, SVA and SVA modifiers, and SRS function. SVA and SVA modifiers were weakly associated with ODI. Although there were more correlations in subset analysis of high-symptom patients, all were weak. Analysis of variance identified significant differences in ODI reported by SVA modifier groups. Conclusion. In primary presentation patients with ASLS and a subset of “high-symptom” patients (ODI ≥ 40), only weak associations between baseline PROs and radiographic parameters were identified. For this patient population, these results suggest regional radiographic parameters (LC, LL, PT, PI-LL mismatch) are not drivers of PROs and cannot be used to extrapolate effect on patient-perceived pathology. Level of Evidence: 2