Faculty Bibliography

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.

OBJECT/OBJECTIVE:A reported risk factor for adjacent-segment disease is injury to the superior facet joint from pedicle screw placement. Given that the facet joint is not typically visualized during percutaneous pedicle screw insertion, there is a concern for increased facet violation (FV) in minimally invasive fusion procedures. The purpose of this study was to analyze and compare the incidence of FV among patients undergoing minimally invasive transforaminal lumbar interbody fusion (MITLIF) and open transforaminal lumbar interbody fusion (TLIF). The impact of O-arm navigation compared with traditional fluoroscopy on FV in MITLIF is also assessed, as are risk factors for FV. METHODS:The authors identified a consecutive population of patients who underwent MITLIF with percutaneous pedicle screw placement, as well as a matched cohort of patients who underwent open TLIF. Postoperative CT imaging was assessed to determine intraarticular FV due to pedicle screw placement. Patients were stratified into minimally invasive and open TLIF groups. Within the MITLIF group, the authors performed a subanalysis of image guidance methods used in cases of FV. Two-tailed Student t-test, ANOVA, chi-square testing, and logistic regression were used for statistical analysis. RESULTS:A total of 282 patients were identified, with a total of 564 superior pedicle screw placements. The MITLIF group consisted of 142 patients with 284 screw insertions. The open TLIF group consisted of 140 patients with 280 screw insertions. Overall, 21 (7.4%) of 282 patients experienced FV. A total of 21 screws violated a facet joint for a screw-based FV rate of 3.7% (21 of 564 screws). There were no significant differences between the MITLIF and open TLIF groups in the percentage of patients with FV (6.3% vs 8.6%) and or the percentage of screws with FV (3.2% vs 4.3%) (p = 0.475 and p = 0.484, respectively). Further stratifying the MI group into O-arm navigation and fluoroscopic guidance subgroups, the patient-based rates of FV were 10.8% (4 of 37 patients) and 4.8% (5 of 105 patients), respectively, and the screw-based rates of FV were 5.4% (4 of 74 screws) and 2.4% (5 of 210 screws), respectively. There was no significant difference between the subgroups with respect to patient-based or screw-based FV rates (p = 0.375 and p = 0.442, respectively). The O-arm group had a significantly higher body mass index (BMI) (p = 0.021). BMI greater than 29.9 was independently associated with higher FV (OR 2.36, 95% CI 1.65-8.53, p = 0.039). CONCLUSIONS:The findings suggest that minimally invasive pedicle screw placement is not associated with higher rates of FV. Overall violation rates were similar in MITLIF and open TLIF. Higher BMI, however, was a risk factor for increased FV. The use of O-arm fluoroscopy with computer-assisted guidance did not significantly decrease the rate of FV.

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.

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.

Cervical fractures can result in severe neurological compromise and even death. One of the most commonly injured segments is the C2 vertebrae, which most frequently involves the odontoid process. In this report, we present the unusual case of a 28-year-old female who sustained a C2 vertebral body fracture (comminuted transverse fracture through the body and both transverse processes) that had both a significant distractive and rotational component, causing the fracture to be highly unstable. Application of halo bracing was unsuccessful. The patient subsequently required a C1-C4 posterior spinal fusion. Follow-up computer tomography imaging confirmed fusion and the patient did well clinically thereafter.

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.

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.

Objective : To determine if autologous fat grafting to the posterior pharynx can reduce hypernasality in patients with cleft palate and mild velopharyngeal insufficiency (VPI). Design : Retrospective case series. Setting : Tertiary care center. Patients : Eleven patients with cleft palate status after palatoplasty (with or without secondary speech surgery) with nasendoscopic evidence of VPI. Interventions : Autologous fat was harvested and injected into the posterior pharynx under general anesthesia. Main Outcome Measures : Pre- and postoperative subjective, nasometry, and nasendoscopy data. Apnea-hypopnea indices (AHIs) were also assessed. Comparisons were made using Fisher's exact test, Student's t tests, and relative risk (RR) assessments. Results : An average of 13.1 mL of fat was injected (range: 5 to 22 mL). Mean follow-up was 17.5 months (range: 12 to 25 months). Statistically significant improvements in speech resonance were identified in nasometry (Zoo passage; p  =  .027) and subjective hypernasality assessment (p  =  .035). Eight of the patients (73%) demonstrated normal speech resonance after posterior pharyngeal fat grafting (PPFG) on subjective or objective assessment (p  =  .001). All five patients with previous secondary speech surgeries demonstrated normal speech resonance on similar assessment (RR  =  1.8; p  =  .13). Complete velopharyngeal closure was observed in seven patients on postoperative nasendoscopy. No changes in AHIs were observed (p  =  .581). Conclusion : PPFG may be best used as an adjunct to secondary speech surgery. In this series, PPFG was not accompanied by the negative sequelae of hyponasality, sleep apnea, or airway compromise.

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.

OBJECT/OBJECTIVE:Advances in the management of trauma-induced intracranial hematomas and hemorrhage (epidural, subdural, and intraparenchymal hemorrhage) have improved survival in these conditions over the last several decades. However, there is a paucity of research investigating the relation between patient age and outcomes of surgical treatment for these conditions. In this study, the authors examined the relation between patient age over 80 years and postoperative outcomes following closed head injury and craniotomy for intracranial hemorrhage. METHODS:A consecutive population of patients undergoing emergent craniotomy for evacuation of intracranial hematoma following closed head trauma between 2006 and 2009 was identified. Using multivariable logistic regression models, the authors assessed the relation between age (> 80 vs ≤ 80 years) and postoperative complications, intensive care unit stay, hospital stay, morbidity, and mortality. RESULTS:Of 103 patients, 27 were older than 80 years and 76 patients were 80 years of age or younger. Older age was associated with longer length of hospital stay (p = 0.014), a higher rate of complications (OR 5.74, 95% CI 1.29-25.34), and a higher likelihood of requiring rehabilitation (OR 3.28, 95% CI 1.13-9.74). However, there were no statistically significant differences between the age groups in 30-day mortality or ability to recover to functional baseline status. CONCLUSIONS:The findings suggest that in comparison with younger patients, patients over 80 years of age may be similarly able to return to preinjury functional baselines but may require increased postoperative medical attention in the forms of rehabilitation and longer hospital stays. Prospective studies concerned with the relation between older age, perioperative parameters, and postoperative outcomes following craniotomy for intracranial hemorrhage are needed. Nonetheless, the findings of this study may allow for more informed decisions with respect to the care of elderly patients with intracranial hemorrhage.