Faculty Bibliography

OBJECTIVE There is ample evidence that extent of resection (EOR) is associated with improved outcomes for glioma surgery. However, it is often difficult to accurately estimate EOR intraoperatively, and surgeon accuracy has yet to be reviewed. In this study, the authors quantitatively assessed the accuracy of intraoperative perception of EOR during awake craniotomy for tumor resection. METHODS A single-surgeon experience of performing awake craniotomies for tumor resection over a 17-year period was examined. Retrospective review of operative reports for quantitative estimation of EOR was recorded. Definitive EOR was based on postoperative MRI. Analysis of accuracy of EOR estimation was examined both as a general outcome (gross-total resection [GTR] or subtotal resection [STR]), and quantitatively (5% within EOR on postoperative MRI). Patient demographics, tumor characteristics, and surgeon experience were examined. The effects of accuracy on motor and language outcomes were assessed. RESULTS A total of 451 patients were included in the study. Overall accuracy of intraoperative perception of whether GTR or STR was achieved was 79.6%, and overall accuracy of quantitative perception of resection (within 5% of postoperative MRI) was 81.4%. There was a significant difference (p = 0.049) in accuracy for gross perception over the 17-year period, with improvement over the later years: 1997-2000 (72.6%), 2001-2004 (78.5%), 2005-2008 (80.7%), and 2009-2013 (84.4%). Similarly, there was a significant improvement (p = 0.015) in accuracy of quantitative perception of EOR over the 17-year period: 1997-2000 (72.2%), 2001-2004 (69.8%), 2005-2008 (84.8%), and 2009-2013 (93.4%). This improvement in accuracy is demonstrated by the significantly higher odds of correctly estimating quantitative EOR in the later years of the series on multivariate logistic regression. Insular tumors were associated with the highest accuracy of gross perception (89.3%; p = 0.034), but lowest accuracy of quantitative perception (61.1% correct; p < 0.001) compared with tumors in other locations. Even after adjusting for surgeon experience, this particular trend for insular tumors remained true. The absence of 1p19q co-deletion was associated with higher quantitative perception accuracy (96.9% vs 81.5%; p = 0.051). Tumor grade, recurrence, diagnosis, and isocitrate dehydrogenase-1 (IDH-1) status were not associated with accurate perception of EOR. Overall, new neurological deficits occurred in 8.4% of cases, and 42.1% of those new neurological deficits persisted after the 3-month follow-up. Correct quantitative perception was associated with lower postoperative motor deficits (2.4%) compared with incorrect perceptions (8.0%; p = 0.029). There were no detectable differences in language outcomes based on perception of EOR. CONCLUSIONS The findings from this study suggest that there is a learning curve associated with the ability to accurately assess intraoperative EOR during glioma surgery, and it may take more than a decade to be truly proficient. Understanding the factors associated with this ability to accurately assess EOR will provide safer surgeries while maximizing tumor resection.

Surgery guided by 5-aminolevulinic acid (ALA) fluorescence has become a valuable adjunct in the resection of malignant intracranial gliomas. Furthermore, the fluorescence intensity of biopsied areas of a resection cavity correlates with histological identification of tumor cells. However, in the case of lesions deep within a resection cavity, light penetration may be suboptimal, resulting in less excitation of 5-ALA metabolites, leading to decreased fluorescence emission. To address this obstacle, the authors report on the use of a 400-nm wavelength fiber-optic lighted suction instrument that can be used both during resection of a tumor and to provide direct light to deeper areas of a resection cavity. In the presented case, this wavelength-specific lighted suction instrument improved the fluorescence intensity of patches of malignant tissue within the resection cavity. This technique may further improve the utility of 5-ALA in identifying tumor-infiltrated tissue for deep-seated lesions. Additionally, this tool may have implications for scoring systems that correlate 5-ALA fluorescence intensity with histological identification of malignant cells.

INTRODUCTION:Brachytherapy is a major adjuvant modality for neoplasms, but few have trialed its use for spinal tumors. This study examines perioperative and oncologic outcomes of patients with malignant spinal tumors who underwent resection with intraoperative phosphorous-32 (P32) brachytherapy. METHODS:Consecutive adult patients who underwent P32 brachytherapy during malignant spinal tumor resection were retrospectively identified from 2014 to 2015. Complications, tumor recurrence, and survival were reviewed. A comprehensive review of the literature was performed. RESULTS:A total of 8 patients were included. Average age was 54.3 years, and 25.0% were males. Tumor types included metastatic leiomyosarcoma, chordoma, multifocal recurrent ependymomas, breast metastasis, malignant meningioma, and myxofibrosarcoma. One-half of patients underwent en bloc tumor resection. P32 plaques were applied to 2 sites per patient for mean 13.1 minutes per site with a goal penetration of 10 Gy to 1-mm depth. Perioperative complications occurred in 3 patients (37.5%), including a persistent cerebral spinal fluid leak, deep infection requiring reoperation, and sacral insufficiency fracture. At a mean 25.6 months follow-up, local recurrence rate was 25.0%, and overall survival was 75.0%. Mean time to recurrence was 14.4 months. Survival at 6, 12, 18, and 24 months was 100.0%, 100.0%, 85.7%, and 71.4%, respectively. CONCLUSIONS:The use of P32 is safe and feasible. P32 intraoperative brachytherapy does not seem to increase the rate of complications. The sample size of this series is small with heterogeneity in tumor type, but recurrence and survival outcomes seem promising compared with previous reports. Further clinical trials are needed.

Pedicle aplasia is an uncommon congenital anomaly most frequently involving the absence of a single pedicle at a single vertebral level. Bilateral pedicle aplasia at multiple levels is exceedingly rare and has only been described once previously in the literature. While single-level pedicle aplasia is often asymptomatic and discovered incidentally, pedicle aplasia of multiple levels may produce severe spinal deformities and neurological deficits. Due to the rarity of this condition, optimal management remains uncertain. In this case report, the authors describe the surgical management of a healthy 9-year-old boy who presented with frequent falls, difficulty running, and severe thoracic kyphotic deformity and was found to have bilateral pedicle aplasia from T3 to T9. A review of the literature regarding pedicle aplasia is also presented.

BACKGROUND:Patient safety is foundational to neurosurgical care. Postprocedural "debrief" checklists have been proposed to improve patient safety, but data about their use in neurosurgery are limited. Here, we implemented an initiative to routinely perform postoperative debriefs and evaluated the impact of debriefing on operating room (OR) safety culture. METHODS:A 10-question safety attitude questionnaire (SAQ) was sent to neurosurgical OR staff at a major academic medical center before and 18 months after the implementation of a postoperative debriefing initiative. Rates of debrief compliance and changes in attitudes before and after the survey were evaluated. The survey used a Likert scale and analyzed with standard statistical methods. RESULTS:After the debrief initiative, the rate of debriefing increased from 51% to 86% of cases for the neurosurgery service. Baseline SAQ responses found that neurosurgeons had a more favorable perception of OR safety than did anesthesiologists and nurses. After implementation of the postoperative debriefing process, perceptions of OR safety significantly improved for neurosurgeons, anesthesiologists, and nurses. Furthermore, the disparity between nurses and surgeons was no longer significant. After debrief implementation, neurosurgical OR staff had improved perceptions of patient safety compared with surgical services that did not commonly perform debriefing. Debriefing identified OR efficiency concerns in 26.9% of cases, and prevention of potential adverse events/near misses was reported in 8% of cases. CONCLUSIONS:Postoperative debriefing can be effectively introduced into the OR and improves the safety culture after implementation. Debriefing is an effective tool to identify OR inefficiencies and potential adverse events.

Choroid plexus papillomas (CPPs) are typically benign tumors that can occur in any age group but are more commonly found in pediatric patients. Although these tumors are benign, there are several reports in adult patients of distant metastases present either at the time of diagnosis or occurring months to years after initial resection. Here, the authors report the case of a 14-year-old boy who presented with symptoms of elevated intracranial pressure due to obstructive hydrocephalus that was caused by a large fourth ventricular mass. Preoperative imaging included a full MRI of the spine, which revealed an intradural lesion that encased the distal sacral nerve roots at the tip of the thecal sac and was concerning for a drop metastasis. The patient underwent gross-total resection of both the fourth ventricular and sacral tumors with histology of both lesions consistent with benign CPP (WHO Grade I). In addition, the authors review prior reports of both pediatric and adult patients in whom benign CPPs have metastasized with either benign or atypical pathology found at a distant site. Taking into account this unusual case and reports in the literature, patients with even benign CPPs may warrant initial and routine follow-up imaging of the total neural axis in search of the rare, but possible, occurrence of drop metastasis.

OBJECTIVE Adult spinal deformity (ASD) develops in the setting of asymmetrical arthritic degeneration, and can also be due to iatrogenic causes, such as prior surgery. Many patients who present with ASD have undergone prior spine surgery with instrumentation. Unfortunately, contemporary studies that evaluate the effect of prior surgery or instrumentation on perioperative outcomes, readmission rates, and need for reoperation are lacking. METHODS All ASD patients who underwent a 3-column osteotomy performed by the senior author at the authors' institution for correction of thoracolumbar spinal deformity between 2006 and 2016 were identified. The authors compared surgical outcomes between primary (first-time) and revision cases. Further subgroup analysis was conducted to investigate the effect of the number of prior surgeries (0, 1, 2, 3, 4, and 5 or more) and the presence of spinal instrumentation on outcomes. Multivariate analysis was used to adjust for relevant and significant confounders. RESULTS A total of 300 patients were included; 38.3% of patients were male. The overall perioperative complication rate was 24.7%, and the mean length of hospitalization was 8.2 days. The 90-day readmission rate was 9.0%, and the overall follow-up reoperation rate was 26.7%. There were no significant differences in complication rates (26.6% vs 24.0%, p = 0.645), length of hospitalization (8.7 vs 7.9 days, p = 0.229), readmission rates (11.4% vs 8.1%, p = 0.387), or reoperation rates (26.6% vs 26.7%, p = 0.984) between primary and revision cases. There was no significant difference in wound complications (infections/dehiscence) requiring reoperation (5.1% vs 6.3%, p = 0.683). Subgroup analysis conducted to evaluate the effect of the number of prior spinal surgeries or the presence of spinal instrumentation did not reveal significant differences for the aforementioned surgical outcomes. In adjusted multivariate analysis, there were no significant associations between history of prior surgery (number of prior surgeries and prior instrumentation) and all of the surgical outcomes of interest. CONCLUSIONS The findings from this study suggest that patients who have undergone prior spine surgery with or without instrumentation are not at increased risk for perioperative complications, need for readmission, or reoperation following 3-column osteotomy of the thoracolumbar spine.

OBJECTIVE During the mini-open posterior corpectomy, percutaneous instrumentation without fusion is performed above and below the corpectomy level. In this study, the authors' goal was to compare the perioperative and long-term implant failure rates of patients who underwent nonfused percutaneous instrumentation with those of patients who underwent traditional open instrumented fusion. METHODS Adult patients who underwent posterior thoracic corpectomies with cage reconstruction between 2009 and 2014 were identified. Patients who underwent mini-open corpectomy had percutaneous instrumentation without fusion, and patients who underwent open corpectomy had instrumented fusion above and below the corpectomy site. The authors compared perioperative outcomes and rates of implant failure requiring reoperation between the open (fused) and mini-open (unfused) groups. RESULTS A total of 75 patients were identified, and 53 patients (32 open and 21 mini-open) were available for followup. The mean patient age was 52.8 years, and 56.6% of patients were male. There were no significant differences in baseline variables between the 2 groups. The overall perioperative complication rate was 15.1%, and there was no significant difference between the open and mini-open groups (18.8% vs 9.5%; p = 0.359). The mean hospital stay was 10.5 days. The open group required a significantly longer stay than the mini-open group (12.8 vs 7.1 days; p < 0.001). Overall implant failure rates requiring reoperation were 1.9% at 6 months, 9.1% at 1 year, and 14.7% at 2 years. There were no significant differences in reoperation rates between the open and mini-open groups at 6 months (3.1% vs 0.0%, p = 0.413), 1 year (10.7% vs 6.2%, p = 0.620), and 2 years (18.2% vs 8.3%, p = 0.438). The overall mean follow-up was 29.2 months. CONCLUSIONS These findings suggest that percutaneous instrumentation without fusion in mini-open transpedicular corpectomies offers similar implant failure and reoperation rates as open instrumented fusion as far out as 2 years of follow-up.

BACKGROUND:Atypical and malignant meningiomas can recur despite resection and radiation. OBJECTIVE:To determine outcomes of patients with recurrent atypical or malignant meningioma treated with repeat resection and permanent iodine-125 ( 125 I) brachy-therapy. METHODS:Charts of patients who underwent surgical resection and 125 I brachyther-apy implantation for atypical and malignant meningiomas between 1988 and 2013 were retrospectively reviewed. The Kaplan-Meier actuarial method was used to calculate progression-free and overall survival. The log-rank test was used to compare groups. Significance was set at P < .05. RESULTS:Forty-two patients underwent 50 resections with 125 I brachytherapy im-plantations. All patients had undergone previous resections and 85% had previously undergone radiation. Median follow-up was 7.5 years after diagnosis and 2.3 years after brachytherapy. Median time to progression after resection with 125 I brachytherapy was 20.9 months for atypical meningioma, 11.4 months for malignant meningioma, and 11.4 months for the combined groups. Median survival after re-resection and 125 I brachytherapy was 3.5 years for atypical meningioma, 2.3 years for malignant menin-gioma, and 3.3 years for all subjects. Median overall survival after diagnosis was 11.1 years for atypical meningioma, 9.1 years for malignant meningioma, and 9.4 years for all subjects. Complications occurred in 17 patients and included radiation necrosis (n = 8, 16%), wound breakdown (n = 6, 12%), hydrocephalus (n = 4, 8%), infection (n = 3, 6%), and a pseudomeningocele (n = 2, 5%). CONCLUSION:This is the largest experience with adjuvant 125 I brachytherapy for recurrent high-grade meningiomas. The outcomes support the use of adjuvant brachytherapy as an option for these aggressive tumors.

OBJECTIVE Functional mapping using direct cortical stimulation is the gold standard for the prevention of postoperative morbidity during resective surgery in dominant-hemisphere perisylvian regions. Its role is necessitated by the significant interindividual variability that has been observed for essential language sites. The aim in this study was to determine the statistical probability distribution of eliciting aphasic errors for any given stereotactically based cortical position in a patient cohort and to quantify the variability at each cortical site. METHODS Patients undergoing awake craniotomy for dominant-hemisphere primary brain tumor resection between 1999 and 2014 at the authors' institution were included in this study, which included counting and picture-naming tasks during dense speech mapping via cortical stimulation. Positive and negative stimulation sites were collected using an intraoperative frameless stereotactic neuronavigation system and were converted to Montreal Neurological Institute coordinates. Data were iteratively resampled to create mean and standard deviation probability maps for speech arrest and anomia. Patients were divided into groups with a "classic" or an "atypical" location of speech function, based on the resultant probability maps. Patient and clinical factors were then assessed for their association with an atypical location of speech sites by univariate and multivariate analysis. RESULTS Across 102 patients undergoing speech mapping, the overall probabilities of speech arrest and anomia were 0.51 and 0.33, respectively. Speech arrest was most likely to occur with stimulation of the posterior inferior frontal gyrus (maximum probability from individual bin = 0.025), and variance was highest in the dorsal premotor cortex and the posterior superior temporal gyrus. In contrast, stimulation within the posterior perisylvian cortex resulted in the maximum mean probability of anomia (maximum probability = 0.012), with large variance in the regions surrounding the posterior superior temporal gyrus, including the posterior middle temporal, angular, and supramarginal gyri. Patients with atypical speech localization were far more likely to have tumors in canonical Broca's or Wernicke's areas (OR 7.21, 95% CI 1.67-31.09, p < 0.01) or to have multilobar tumors (OR 12.58, 95% CI 2.22-71.42, p < 0.01), than were patients with classic speech localization. CONCLUSIONS This study provides statistical probability distribution maps for aphasic errors during cortical stimulation mapping in a patient cohort. Thus, the authors provide an expected probability of inducing speech arrest and anomia from specific 10-mm² cortical bins in an individual patient. In addition, they highlight key regions of interindividual mapping variability that should be considered preoperatively. They believe these results will aid surgeons in their preoperative planning of eloquent cortex resection.