Faculty Bibliography

Severe thoracic kyphosis caused by pathologic fractures often needs to be corrected by resection of the collapsed vertebral body, reconstruction of the anterior spinal column, and correction of the kyphosis with long-segment fixation. The resection of this pathologic bone functions essentially as a vertebral column resection. With the advent of minimally invasive technology, the powerful corrective forces afforded in open cases can be applied using a less invasive approach. In this article, we describe a mini-open posterior technique for thoracic kyphosis via a vertebrectomy and cantilever technique. Two patients underwent kyphosis correction via mini-open vertebrectomy. One patient was corrected from 92 degrees to 65 degrees, and the second patient was corrected from 70 degrees to 53 degrees. Both patients underwent a mini-open approach. Cantilever correction was accomplished over an expandable cage with a minimally invasive pedicle screw system. We describe our technique of mini-open vertebral column resection and kyphosis correction in the thoracic spine.

Holospinal epidural abscess (HEA) is an extremely rare condition in which spinal epidural abscesses extend from the cervical to the sacral spine. We report two patients who presented with myelopathy secondary to HEA. Both patients underwent urgent surgical decompression and abscess drainage, and had significant improvement in neurological function. We discuss the surgical management strategies and briefly review the literature regarding HEA.

BACKGROUND:Local recurrence of spinal metastasis after surgical resection is relatively common. We sought to determine risk factors and independent predictors for local recurrence after primary surgical resection of spinal metastasis. METHODS:Demographic and clinical variables were collected for patients who underwent surgery for spinal metastasis June 2005 to June 2011. Primary outcome of interest was local recurrence. Significant associations between covariates of interest and recurrence were identified using the chi-square test. Multivariable logistic regression models for recurrence risk were fit and adjusted for potential confounders. RESULTS:A total of 99 patients were analyzed. Mean time to metastatic recurrence was 9.8 months. Thirty-two patients (32.3 %) had local recurrence of metastatic disease following initial surgery. Patients who underwent radiotherapy had significantly higher recurrence rates than patients who did not (39.2 % vs. 12.0 %, respectively; P = 0.012). Patients with metastatic disease affecting more levels had significantly lower recurrence rates. On multivariate analysis, older age was an independent predictor of decreased likelihood of local recurrence. Melanoma was the only cancer type independently associated with higher risk for recurrence. Patients with recurrence had significantly higher 1- and 2-year survival rates than patients without recurrence. Median length of survival was longer in the recurrent group as well. CONCLUSIONS:Other than melanoma, covariates significantly associated with recurrence were factors likely associated with increased survival, including less-extensive spinal disease and radiotherapy. Thus, longer survival time following surgery likely results in a greater chance for local recurrence. As advancements in treatment provide prolonged survival, local recurrence rates will likely increase.

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

Desmoplastic fibroma (DF) is a rare bone tumor that accounts for about 0.1%-0.3% of all bone tumors. It is typically characterized as slow growing, but in rare cases it can proliferate extensively and exhibit locally aggressive characteristics. It is found most commonly in the appendicular skeleton and rarely in the axial skeleton. The authors present the cases of 2 women in their 20s with DF originating from the cervicothoracic spine. Both tumors intimately involved the brachial plexus and caused significant impingement of the mediastinum resulting in cardiopulmonary compromise. Both patients underwent hemiclamshell thoracotomies for tumor resection, and in both cases subtotal resection was performed given the encasement of the brachial plexus. Although DF is a benign process, it can be locally aggressive and proliferate at extensive rates. The authors describe these 2 cases, review the literature, and discuss management.

Surgery is an essential component in the treatment of brain tumors. However, delineating tumor from normal brain remains a major challenge. We describe the use of stimulated Raman scattering (SRS) microscopy for differentiating healthy human and mouse brain tissue from tumor-infiltrated brain based on histoarchitectural and biochemical differences. Unlike traditional histopathology, SRS is a label-free technique that can be rapidly performed in situ. SRS microscopy was able to differentiate tumor from nonneoplastic tissue in an infiltrative human glioblastoma xenograft mouse model based on their different Raman spectra. We further demonstrated a correlation between SRS and hematoxylin and eosin microscopy for detection of glioma infiltration (κ = 0.98). Finally, we applied SRS microscopy in vivo in mice during surgery to reveal tumor margins that were undetectable under standard operative conditions. By providing rapid intraoperative assessment of brain tissue, SRS microscopy may ultimately improve the safety and accuracy of surgeries where tumor boundaries are visually indistinct.

Paragangliomas are relatively rare tumors, accounting for only about 0.3% of all neoplasms. Most paragangliomas are defined as benign in nature, but 10-20% possess metastatic potential. There have been scattered reports of metastatic paraganglioma in the literature, but in rare circumstances, paragangliomas can metastasize to the spinal column causing destruction or compression of the spinal cord, clinically manifesting as pain or neurological deficit. We report a case of metastatic paraganglioma in which a 47-year-old man had spinal metastasis from a primary abdominal paraganglioma and was found to be positive for SDHB mutation, portraying negative implications for prognosis. Long-term follow-up is reported. In addition, we review the literature on the topic of metastatic paraganglioma, management of paragangliomas involving spine, and touch on the importance of the presence of SDHB mutations in these cases.

OBJECT/OBJECTIVE:Minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) has proven to be effective in the treatment of spondylolisthesis and degenerative disc disease (DDD). Compared with the traditional open TLIF, the MI procedure has been associated with less blood loss, less postoperative pain, and a shorter hospital stay. However, it is uncertain whether the advantages of an MI TLIF also apply specifically to obese patients. This study was dedicated to evaluating whether obese patients reap the perioperative benefits similar to those seen in patients with normal body mass index (BMI) when undergoing MI TLIF. METHODS:Obese patients-that is, those with a BMI of at least 30 kg/m(2)-who had undergone single-level TLIF were retrospectively identified and categorized according to BMI: Class I obesity, BMI 30.0-34.9 kg/m(2); Class II obesity, BMI 35.0-39.9 kg/m(2); or Class III obesity, BMI ≥ 40.0 kg/m(2). In each obesity class, patients were stratified by TLIF approach, that is, open versus MI. Perioperative outcomes, including intraoperative estimated blood loss (EBL), complications (overall, intraoperative, and 30-day postoperative), and hospital length of stay (LOS), were compared. The chi-square test, Fisher exact test, or 2-tailed Student t-test were used when appropriate. RESULTS:One hundred twenty-seven patients were included in the final analysis; 49 underwent open TLIF and 78 underwent MI TLIF. Sixty-one patients had Class I obesity (23 open and 38 MI TLIF); 45 patients, Class II (19 open and 26 MI); and 21 patients, Class III (7 open and 14 MI). Overall, mean EBL was 397.2 ml and mean hospital LOS was 3.7 days. Minimally invasive TLIF was associated with significantly less EBL and a shorter hospital stay than open TLIF when all patients were evaluated as a single cohort and within individual obesity classes. Overall, the complication rate was 18.1%. Minimally invasive TLIF was associated with a significantly lower total complication rate (11.5% MI vs 28.6% open) and intraoperative complication rate (3.8% MI vs 16.3% open) as compared with open TLIF. When stratified by obesity class, MI TLIF was still associated with lower rates of total and intraoperative complications. This effect was most profound and statistically significant in patients with Class III obesity (42.9% open vs 7.1% MI). CONCLUSIONS:Minimally invasive TLIF offers obese patients perioperative benefits similar to those seen in patients with normal BMI who undergo the same procedure. These benefits include less EBL, a shorter hospital stay, and potentially fewer complications compared with open TLIF. Additional large retrospective studies and randomized prospective studies are needed to verify these findings.

OBJECT/OBJECTIVE:The use of intraoperative neurophysiological monitoring (IONM) in surgical decompression surgery for myelopathy may assist the surgeon in taking corrective measures to reduce or prevent permanent neurological deficits. We evaluated the efficacy of IONM in cervical and cervicothoracic spondylotic myelopathy (CSM) cases. METHODS:The authors retrospectively reviewed 140 cases involving patients who underwent surgery for CSM utilizing IONM during 2011 at the University of California, San Francisco. Data on preoperative clinical variables, intraoperative changes in transcranial motor evoked potentials (MEPs), and postoperative new neurological deficits were collected. Associations between categorical variables were analyzed with the Fisher exact test. RESULTS:Of the 140 patients, 16 (11%) had significant intraoperative decreases in MEPs. In 8 of these cases, the MEP signal did not return to baseline values by the end of the operation. There were 8 (6%) postoperative deficits, of which 6 were C-5 palsies and 2 were paraparesis. Six of the patients with postoperative deficits had demonstrated persistent MEP signal change on IONM. There was a significant association between persistent MEP changes and postoperative deficits (p < 0.001). The sensitivity of intraoperative MEP monitoring was 75%, the specificity 98%, the positive predictive value 75%, and the negative predictive value 98%. Due to higher rates of false negatives, the sensitivity decreased to 60% in the subgroup of patients with vascular disease comorbidity. The sensitivity increased to 100% in elderly patients and in patients with preoperative motor deficits. The sensitivity and positive predictive value of deltoid and biceps MEP changes in predicting C-5 palsy were 67% and 67%, respectively. CONCLUSIONS:The authors found a correlation between decreased intraoperative MEPs and postoperative new neurological deficits in patients with CSM. Sensitivity varies based on patient comorbidities, age, and preoperative neurological function. Monitoring of MEPs is a useful adjunct for CSM cases, and the authors have developed a checklist to standardize their responses to intraoperative MEP changes.

PURPOSE/OBJECTIVE:Surgery for spinal metastasis is often associated with significant morbidity. Despite a number of preoperative scoring systems/scales and identified variables that have been reported to predict complication risk, clinical studies that directly evaluate this issue using multivariate analysis are scarce. The goal of our study was to assess independent predictors of complication after surgery for spinal metastasis. METHODS:We queried electronic medical records to identify a consecutive population of adult patients who underwent surgery for spinal metastasis for the period June 2005 through June 2011. Utilizing multivariate logistic regression, we assessed independent predictors of perioperative and postoperative adverse events. RESULTS:A total of 106 patients were included in the final analysis. Overall complication rate was 21.7 %. Independent predictors for higher rates of complication were age greater than 40 years [40-65 years had odds ratio (OR) 1.91, 95 % confidence interval (CI) 1.02-16.78 and >65 years had OR 5.17, 95 % CI 1.54-29.81] and metastatic lesions involving three or more contiguous levels of the spine (OR 2.76, 95 % CI 1.09-9.61). CONCLUSIONS:Patients older than 40 years or patients who have metastatic lesions involving three or more contiguous vertebral levels appear to be at higher risk for complication. Patients older than 65 years have the greatest likelihood of complication.