Abstract BACKGROUND For optimizing high-grade glioma resection, 5-aminolevulinic acid is a reliable tool. However, its efficacy in low-grade glioma resection remains unclear. OBJECTIVE To study the role of 5-aminolevulinic acid in low-grade glioma resection and assess positive fluorescence rates and the effect on the extent of resection. METHODS A systematic review of PubMed, Google Scholar, and Cochrane was performed from the date of inception to February 1, 2019. Studies that correlated 5-aminolevulinic acid fluorescence with low-grade glioma in the setting of operative resection were selected. Studies with biopsy only were excluded. Positive fluorescence rates were calculated. The quality index of the selected papers was provided. No patient information was used, so Institutional Review Board approval and patient consent were not required. RESULTS A total of 12 articles met the selection criteria with 244 histologically confirmed low-grade glioma patients who underwent microsurgical resection. All patients received 20 mg/kg body weight of 5-aminolevulinic acid. Only 60 patients (n = 60/244; 24.5%) demonstrated visual intraoperative 5-aminolevulinic acid fluorescence. The extent of resection was reported in 4 studies; however, the data combined low- and high-grade tumors. Only 2 studies reported on tumor location. Only 3 studies reported on clinical outcomes. The Zeiss OPMI Pentero microscope was most commonly used across all studies. The average quality index was 14.58 (range: 10-17), which correlated with an overall good quality. CONCLUSION There is an overall low correlation between 5-aminolevulinic acid fluorescence and low-grade glioma. Advances in visualization technology and using standardized fluorescence quantification methods may further improve the visualization and reliability of 5-aminolevulinic acid fluorescence in low-grade glioma resection.
Simulation has been adopted as a powerful training tool in many areas of health care. However, it has not yet been systematically embraced in neurosurgery because of the absence of validated tools, assessment scales, and curricula. To use our validated microanastomosis module and scale to evaluate the effects of an educational intervention on the performance of neurosurgery residents at the 2012 Congress of Neurological Surgeons Annual Meeting. The module consisted of an end-to-end microanastomosis of a 3-mm vessel and was divided into 3 phases: (1) a cognitive and microsuture prelecture testing phase, (2) a didactic lecture, and (3) a cognitive and microsuture postlecture testing phase. We compared resident knowledge and technical proficiency from the pretesting and posttesting phases. One neurosurgeon and 7 neurosurgery residents participated in the study. None had previous experience in microsurgery. The average score on the microsuture prelecture and postlecture tests, as measured by our assessment scale, was 32.50 and 39.75, respectively (P = .001). The number of completed sutures at the end of each procedure was higher for 75% of participants in the postlecture testing phase (P = .03). The average score on the cognitive postlecture test (12.75) was significantly better than that of the cognitive prelecture test (8.38; P = .001). Simulation has the potential to enhance resident education and to elevate proficiency levels. Our data suggest that a focused microsurgical module that incorporates a didactic component and a technical component can enhance resident knowledge and technical proficiency in microsurgical anastomosis.
Intraoperative imaging can affect decision making and outcomes in neurovascular surgery. Current modalities have limitations: Duplex ultrasonography is associated with poor definition; continuous-wave Doppler fails at quantifying the degree of vessel stenosis; and invasive catheter angiography, the gold standard, is time-consuming and carries hemorrhagic and thromboembolic risk. Optical coherence tomography (OCT), a new optical imaging technique that uses infrared light to produce real-time cross-sectional images similar to ultrasonography but with significantly higher resolution (up to 5 to 10 μm), has been used successfully on endovascular catheters to image vessel walls.1 OCT has been shown to resolve arterial wall structures differentiating between intima, media, and adventitia.2 It can even delineate different types of tissue in an atheroma such as lipid, calcium, and fibrous cap.3 Furthermore, OCT permits 4-dimensional (3 spatial dimensions plus time) reconstruction of the vessel lumen. These advantages have allowed endovascular OCT to emerge as an adjuvant vascular intraoperative imaging technique; its utility, however, remains limited by the need for percutaneous arterial access and its short optimal imaging time (2 seconds). Using OCT extravascularly could have several benefits in open vascular neurosurgery. To evaluate extravascular OCT as a high-resolution noninvasive imaging modality, Wicks et al4 assessed the ability of a custom-built OCT device to image the antiatherosclerotic effect of pravastatin therapy in a murine model of carotid atherosclerosis. The experimenters randomized wild-type mice and apolipoprotein E (ApoE)-deficient mice (susceptible to plaque development) to 3 treatment groups: wild-type mice (n = 13) on standard diet; ApoE-deficient mice (n = 13) on high-fat, atherosclerotic diet; and ApoE-deficient mice (n = 13) on high-fat, atherosclerotic diet and daily pravastatin. Their hypothesis was that atherosclerotic changes that should be observed mainly in groups 2 and 3 should be detectable by OCT. To test this hypothesis, the authors conducted 2 independent studies. Study 1, a validation study, aimed to determine the optimal time for carotid plaque development and the validity of the surgical procedure. OCT imaging was performed at 8 weeks (n = 1 per group), 10 weeks (n = 1 per group), and 14 weeks (n = 3 per group). After the mice underwent surgical carotid exposure and OCT imaging, they were either kept alive for second imaging or euthanized and perfused for in situ carotid artery imaging with the aim of comparing plaque morphology with the in vivo images. Study 2 aimed to establish the sensitivity and specificity of OCT imaging in determining the presence and size of atherosclerotic plaques in the 3 groups. For this purpose, mice (n = 8 per group) were administered their designated diet and treatment for 1 week. They then underwent in vivo OCT imaging and postperfusion in situ OCT imaging. After resection of the carotid arteries, the authors compared histological sections with OCT images (Figure).Figure: Murine carotid artery lumen patency percentage as calculated by live optical coherence tomography (OCT) imaging, postperfusion OCT imaging, and histology. ApoE KO, apolipoprotein E knockout; HFD, high-fat diet. Reprinted with permission from Wicks RT, Huang Y, Zhang K, et al. Extravascular optical coherence tomography: evaluation of carotid atherosclerosis and pravastatin therapy. Stroke. 2014;45(4):1123-1130.The validation study (study 1) showed that plaque development was initially seen with OCT imaging at 8 weeks and optimally developed at 14 weeks in all ApoE-deficient mice on atherosclerotic diet. In that study, ApoE-deficient mice on pravastatin therapy had a lesser degree of plaque development. In study 2, OCT imaging demonstrated the presence of carotid plaques in all ApoE-deficient mice on high-fat diet. Furthermore, OCT had 100% sensitivity and specificity for plaque detection in comparisons of the 3 groups. This interesting study reveals that OCT offers the potential for a real-time, high-resolution vessel lumen evaluation with simultaneous 4-dimensional reconstruction. This promising technology has the potential to analyze vessel wall characteristics, which could influence revascularization and clipping strategies. The technology may also prove useful during carotid endarterectomies. Integration of imaging technologies into microscopes and image guidance systems are necessary steps for developing the next-generation operating room.
Microsurgical skills remain an integral component of neurosurgical education. There is a need for an objective scale to assess microsurgical skills. The objective of this study was to assess the face and construct validity of a bench training microanastomosis module and an objective assessment scale, i.e., the Northwestern Objective Microanastomosis Assessment Tool (NOMAT).Medical students, neurosurgical residents, and postdoctoral research fellows at Northwestern University were enrolled in the study. Trainees were divided into 3 groups based on microsurgical experience: 1) experienced, 2) exposed, and 3) novices. Each trainee completed two end-to-end microanastomoses using a 1-mm and a 3-mm synthetic vessel. Two cameras were installed to capture procedural footage. One neurosurgeon blindly graded the performance of trainees using both objective and subjective methods to assess construct validity. Two neurosurgeons reviewed the contents of the simulation module to assess face validity.Twenty-one trainees participated in the study, including 6 experienced, 6 exposed, and 9 novices. The mean NOMAT score for experienced trainees on the 1-mm module was 47.3/70 compared with 26.0/70 and 25.8/70 for exposed and novice trainees, respectively (p = 0.02). Using subjective grading, experienced trainees performed significantly better on the 1-mm module (64.2/100) compared with exposed or novice trainees (23.3/100 and 25.0/100, respectively; p = 0.02). No statistical difference between groups was noted for the 3-mm module with both NOMAT and subjective grading. Experienced trainees took less time to perform both tasks compared with the others.Face and construct validities of the microanastomosis module were established. The scale and the microanastomosis module could help assess the microsurgical skills of neurosurgical trainees and serve as a basis for the creation of a microsurgical curriculum.
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Retrospective case control.The purpose of the current study is to determine risk factors associated with chronic opioid use after spine surgery.In our single institution retrospective study, 1,299 patients undergoing elective spine surgery at a tertiary academic medical center between January 2010 and August 2017 were enrolled into a prospectively collected registry. Patients were dichotomized based on renewal of, or active opioid prescription at 3-mo and 12-mo postoperatively. The primary outcome measures were risk factors for opioid renewal 3-months and 12-months postoperatively. These primarily included demographic characteristics, operative variables, and in-hospital opioid consumption via morphine milligram equivalence (MME). At the 3-month and 12-month periods, we analyzed the aforementioned covariates with multivariate followed by bivariate regression analyses.Multivariate and bivariate analyses revealed that script renewal at 3 months was associated with black race (P = 0.001), preoperative narcotic (P < 0.001) or anxiety/depression medication use (P = 0.002), and intraoperative long lumbar (P < 0.001) or thoracic spine surgery (P < 0.001). Lower patient income was also a risk factor for script renewal (P = 0.01). Script renewal at 12 months was associated with younger age (P = 0.006), preoperative narcotics use (P = 0.001), and ≥4 levels of lumbar fusion (P < 0.001). Renewals at 3-mo and 12-mo had no association with MME given during the hospital stay or with the usage of PCA (P > 0.05).The current study describes multiple patient-level factors associated with chronic opioid use. Notably, no metric of perioperative opioid utilization was directly associated with chronic opioid use after multivariate analysis.
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