Sex differences in time course and diagnostic accuracy of GFAP and UCH-L1 in trauma patients with mild traumatic brain injury.

Glial Fibrillary Acidic Protein (GFAP) and Ubiquitin C-terminal hydrolase (UCH-L1) have been FDA-approved for clinical use in mild and moderate traumatic brain injury (TBI). Understanding sex differences in their diagnostic accuracy over time will help inform clinical practice. We sought to evaluate the sex differences in the temporal profile of GFAP and UCH-L1 in a large cohort of trauma patients presenting to the emergency department. To compare the biomarkers' diagnostic accuracy in male versus female patients for detecting mild TBI (MTBI), and traumatic intracranial lesions on head CT. This prospective cohort study enrolled female and male adult trauma patients presenting to a Level 1 Trauma Center. All patients underwent rigorous screening to determine whether or not they had experienced a MTBI. Of 3025 trauma patients assessed, 1030 met eligibility criteria and 446 declined. Initial blood samples were obtained in 584 patients enrolled within 4 h of injury. Repeated blood sampling was conducted at 4, 8, 12, 16, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180-h post-injury. The main outcomes included the diagnostic accuracy in detection of MTBI and traumatic intracranial lesions on head CT scan. A total of 1831 samples were drawn in 584 patients over 7 days, 362 (62%) were male and 222 (38%) were female. The pattern of elevation was similar in both sexes. Although the pattern of elevation was similar between male and female for both biomarkers, male patients had significantly higher concentrations of UCH-L1 compared to female patients at several timepoints post-injury, particularly within 24 h of injury. There were no significant differences in diagnostic accuracy for detecting MTBI or for detecting CT lesions between male and female patients at any timepoint for both GFAP and UCH-L1. Although patterns of GFAP and UCH-L1 release in trauma patients over a week post-injury was similar between the sexes, there were significantly higher concentrations of UCH-L1 in males at several timepoints post-injury. Despite this, the overall diagnostic accuracies of both GFAP and UCH-L1 over time for detecting MTBI and CT lesions were not significantly different between male and female trauma patients.

Static Magnetic Fields within Spinal Interbody Cages for the Promotion of Spinal Arthrodesis: A Pilot Study.

BACKGROUND: Spinal arthrodesis is a commonly performed spinal operation. Spinal arthrodesis can be complicated by pseudoarthrosis and resultant hardware failure. Static magnetic fields (SMF) have the ability to improve bone fusion. We seek to assess the feasibility of the construction and implantation of a lumbar interbody cage equipped with a SMF in a caprine model. METHODS: Six skeletally mature female Boer goats underwent a lateral approach for placement of an interbody graft at lumbar (L) 1-2 and 3-4. The goats were divided into 2 groups of 3 animals. The interbody graft contained a neodymium iron boron magnet in the experimental group and a nonmagnetic titanium sham in the control group. Both groups contained a synthetic bone graft. Blinded radiographic and histologic evaluation was performed at predetermined timepoints to assess degree of bony fusion and osseointegration. RESULTS: All 6 goats underwent successful placement of lumbar interbody grafts. At the 1-month postoperative computed tomography, 1 goat in the experimental group and 1 goat in the control group were noted to have dislodged their intervertebral cage. Qualitative radiographic and histologic evaluation identified enhanced bone formation, bone density, and osteointegration of the graft in the experimental group. CONCLUSIONS: A spinal interbody cage containing a neodymium iron boron magnet for the production of a local SMF is feasible. Preliminary data suggests enhanced bone formation, bone density, and osseointegration of the graft.

Experience With the Pipeline Embolization Device for Posterior Circulations Aneurysms: A Multicenter Cohort Study.

BACKGROUND: The Pipeline Embolization Device (PED; Medtronic) has been used off-label for the treatment of challenging posterior circulation aneurysms. Data on this modality are primarily limited to small retrospective single-center series. OBJECTIVE: To assess safety and efficacy of this treatment by establishing an international, multicenter collaboration. METHODS: Consecutive posterior circulation aneurysms treated with the PED from 2012 to 2019 across 11 neurovascular centers were retrospectively reviewed. Baseline demographics, aneurysm and treatment characteristics, complications, occlusion status, and functional outcome were assessed. RESULTS: There were 149 posterior circulation aneurysms treated with PED in 146 patients. A total of 24 (16.4%) patients presented with subarachnoid hemorrhage. Most aneurysms were dissecting/blister (36.2%) in morphology, followed by saccular (35.6%) and fusiform (28.2%). The most common locations were the vertebral (51.7%) and basilar arteries (22.8%). Complete or near-complete occlusion (>90%) was achieved in 90.9% of aneurysms at a median follow-up of 12 mo. Dissecting/blister aneurysms were most likely to occlude (P = .06). Symptomatic neurologic complications occurred in 9.4% of aneurysms, associated with larger size, ruptured presentation, presentations with brain stem compression, cranial nerve palsy, or stroke. Favorable functional outcome (modified Rankin Score 0-2) was achieved in 86.2% of patients. There were 6 fatalities of which 4 occurred in aneurysmal subarachnoid hemorrhage patients. CONCLUSION: This multicenter study shows that PED for the treatment of posterior circulation is preferentially used for the treatment of fusiform and dissecting/blister aneurysm morphologies. Despite the challenges presented by these less-common morphologies, flow diversion may be performed with a neurologic complication rate of about 10% and favorable long-term aneurysm occlusion rates.

The predictive value of low-field strength magnetic resonance imaging for intraoperative residual tumor detection. Clinical article.

OBJECT: Neurosurgeons have been utilizing intraoperative MR (iMR) imaging to evaluate the extent of tumor resection since the 1990s. A low-field strength (0.12 T) MR imaging unit (PoleStar N20, Medtronic) is a practical and relatively inexpensive iMR imaging system that has found increased use in neurosurgery. The gold standard for post operative detection of residual tumor has been high-strength MR imaging performed within 48 hours of resection.The object of this study was to determine the predictive concordance of low-strength iMR imaging with standard high-strength MR imaging for detection of residual tumor. METHODS: The authors retrospectively evaluated the MR images from 74 intracranial tumor resections, comparing the intraoperative images obtained using a 0.12-T iMR imaging unit to the immediate postoperative images obtained using a standard 1.5-T MR imaging unit within 48 hours after surgery. RESULTS: The sensitivity of low-field MR imaging for detection of residual tumor was 0.74 (95% CI 0.58-0.86),and its specificity was 0.97 (95% CI 0.83-1). When only glial tumors (42 of the 74 lesions) were analyzed, the sensitivity was 0.82 (95% CI 0.59-0.94) and the specificity was 0.95 (95% CI 0.73-1). CONCLUSIONS: These data could assist the neurosurgeon who has to decide intraoperatively whether the observed iMR images show residual tumor or not.

Transoral stereotactic technique for clival biopsy.

OBJECTIVE: To report a transoral freehand technique using continuous image guidance to biopsy a clival lesion. METHODS: The patient was placed in a Mayfield head rest. Patient data were registered using preacquired magnetic resonance and computed tomography images, and then, under continuous image guidance, a bone biopsy instrument was advanced freehand through a transoral route into the clival lesion. RESULTS: Bone biopsy instrumentation was successfully placed into the clival lesion. Biopsy forceps were placed through the working channel of the biopsy instrumentation and specimen was successfully retrieved from the clival mass. The patient tolerated the procedure well and the only complaint was dysphagia, which resolved in several days postoperatively. CONCLUSION: The transoral freehand technique with stereotactic navigation was found to be a simple, safe, fast, and effective way to biopsy a clival lesion.

Robotic-assisted superficial temporal artery-to-middle cerebral artery anastomosis.

Robotic-assisted surgery is becoming more prevalent and accepted in the USA and is routine in many medical centers across a variety of specialties, but mainly in urology and general surgery. However, neurosurgery has yet to embrace this new technology. We used the da Vinci(®) robot (Intuitive Surgical, Sunnyvale, California) to perform a robotic-assisted superficial temporal artery-to-middle cerebral artery bypass on a cadaveric head. The object of this technical note is to describe the use of the da Vinci(®) robot to perform an extracranial-intracranial bypass. Using a cadaveric human head, the da Vinci(®) robot was successfully used to anastomose the superficial temporal artery to an M2 branch of the middle cerebral artery. We were successfully able to demonstrate the utility of using the da Vinci(®) robot in extracranial to intracranial anastomosis in a cadaveric head. The optics were excellent and physiologic tremor was eliminated. More studies are needed to assess the feasibility, safety, and utility of this device in living tissue within the field of neurosurgery.