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Autonomous methods to align beamlines can decrease the amount of time spent on diagnostics, and also uncover better global optima leading to better beam quality. The alignment of these beamlines is a high-dimensional expensive-to-sample optimization problem involving the simultaneous treatment of many optical elements with correlated and nonlinear dynamics. Bayesian optimization is a strategy of efficient global optimization that has proved successful in similar regimes in a wide variety of beamline alignment applications, though it has typically been implemented for particular beamlines and optimization tasks. In this paper, we present a basic formulation of Bayesian inference and Gaussian process models as they relate to multi-objective Bayesian optimization, as well as the practical challenges presented by beamline alignment. We show that the same general implementation of Bayesian optimization with special consideration for beamline alignment can quickly learn the dynamics of particular beamlines in an online fashion through hyperparameter fitting with no prior information. We present the implementation of a concise software framework for beamline alignment and test it on four different optimization problems for experiments on X-ray beamlines at the National Synchrotron Light Source II and the Advanced Light Source, and an electron beam at the Accelerator Test Facility, along with benchmarking on a simulated digital twin. We discuss new applications of the framework, and the potential for a unified approach to beamline alignment at synchrotron facilities., (open access.)

Background: Treatments for symptomatic or unstable basilar invagination (BI) include posterior decompression, distraction/fusion, trans-nasal or trans-oral anterior decompression, and combined techniques, with the need for occipitocervical fusion based on the degree of craniocervical instability. Variations of the far lateral transcondylar approach are described in limited case series for BI, but have not been widely applied., Methods: A single-institution, retrospective review of consecutive patients undergoing a far lateral transcondylar approach for odontoidectomy (± resection of the inferior clivus) followed by occipitocervical fusion over a 6-year period (1/1/2016 to 12/31/2021) is performed. Detailed technical notes are combined with images from cadaveric dissections and patient surgeries to illustrate our technique using a lateral retroauricular incision., Results: Nine patients were identified (3 males, 6 females; mean age 40.2 ± 19.6 years). All patients had congenital or acquired BI causing neurologic deficits. There were no major neurologic or wound-healing complications. 9/9 patients (100%) experienced improvement in preoperative symptoms., Conclusions: The far lateral transcondylar approach provides a direct corridor for ventral brainstem decompression in patients with symptomatic BI. A comprehensive knowledge of craniovertebral junction anatomy is critical to the safe performance of this surgery, especially when using a lateral retroauricular incision., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: An enlarged suprameatal tubercle (SMT) can obscure visualization of the trigeminal nerve and require removal during microvascular decompression (MVD) surgery, especially when the superior petrosal vein (SPV) complex is preserved., Objective: To define the incidence and important variables affecting the need for SMT removal with an SPV-sparing trigeminal nerve MVD., Methods: Retrospective single-institution review identified patients who underwent a first-time, SPV-sparing MVD for trigeminal neuralgia (TGN) over a 26-mo period. SMT length (SMT-L), SMT width (SMT-W), and peri-trigeminal cerebellopontine cisternal thickness (CT) were measured from axial high-resolution magnetic resonance images. Need for SMT removal and use of endoscopic assistance was recorded. Data were analyzed using unpaired t-tests, and receiver operating characteristic (ROC)/area under the curve testing., Results: A total of 43 MVD surgeries for TGN on 42 patients (mean age 52.7 ± 14.4 yr) were analyzed. Mean SMT-L, SMT-W, and CT were 9.8 ± 1.6, 2.0 ± 0.8, and 4.2 ± 1.5 mm, respectively. SMT removal via drilling was required in 4/43 cases (9.3%). Endoscopic assistance was used in 3 cases (2 SMT removed and 1 SMT preserved). SMT-W was the biggest predictor of the need for SMT removal on ROC analysis (area under the curve 0.97, 0.92-1.0 95% CI). The combined thresholds of SMT-W ≥ 3.2 mm and CT ≤ 3.5 mm demonstrated 100% sensitive and 100% specificity for the need to remove the SMT on optimal cutoff analysis., Conclusion: SMT drilling is necessary in nearly 10% of SPV-sparing MVDs for TGN. The combination of SMT width and cerebellopontine cistern thickness is predictive of the need for SMT removal., (© Congress of Neurological Surgeons 2021.)

Head and neck malignancies with perineural spread are rare. Patients can present with neuropathic pain and cranial nerve palsies.1 Skull base approaches for surgical decompression are a consideration for patients to provide symptom relief.2 We demonstrate a frontotemporal extradural approach for a patient with worsening visual symptoms and refractory neuropathic pain in the V1, V2, and V3 distributions and briefly review the relevant anatomy.3-7  A 41-yr-old female with a poorly differentiated carcinoma of the head and neck with an infiltration of the cavernous sinus and perineural spread along the trigeminal nerve presented with severe neuropathic facial pain and anesthesia. She had previously undergone radiosurgery. Magnetic resonance imaging (MRI) demonstrated an interval increase in perineural disease within the cavernous sinus with extension intradurally. Her pain was medically refractory. A 2-dimensional intraoperative video illustrates the microsurgical decompression of her perineural invasion along the skull base as a palliative procedure. The patient recovered well postoperatively and had a symptomatic improvement in her pain and visual symptoms. Her preoperative facial numbness persisted postoperatively as expected. Postoperative imaging demonstrates a gross total resection of the intradural component of the tumor with decompression and expected expansion of the cavernous sinus. Because of the retrospective nature of this report, informed consent was not required. Images within the video have been reproduced from Fukuda et al4 with permission from © Georg Thieme Verlag KG; and Matsuo et al5 by permission of the Congress of Neurological Surgeons., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Background: Symptomatic trigeminal neuralgia caused by small (<3 cm) skull base meningiomas is treated by radiosurgery or surgical resection. Although radiosurgery is less invasive, surgical resection provides more rapid resolution of symptoms. We reviewed a short series of patients who underwent an anterior transpetrosal approach for surgical resection of meningiomas causing trigeminal neuralgia., Methods: A retrospective review of 5 consecutive patients with meningiomas causing trigeminal neuralgia of the senior author was included. Preoperative parameters (size, proximity to critical neurovascular structures, presence of brainstem compression), intraoperative parameters (Simpson grade of resection, loss of brainstem evoked potentials, surgical approach), and outcomes (symptom resolution, extent of resection, follow-up) were recorded., Results: Patient median age was 67 years (range, 60-73 years). All patients had symptoms concerning trigeminal neuralgia with 2 having associated areas of facial numbness. The anterior transpetrosal approach was used to achieve complete resection (Simpson grade I). Postresection, the trigeminal nerve and brainstem were clearly visible to evaluate neurovascular structures and ensure decompression. No postoperative complications were reported, and all patients experienced sustained symptomatic relief 1 month postsurgery., Conclusions: With the advent of radiosurgery for skull base meningiomas, surgical resection is not always considered; however, such meningiomas causing trigeminal neuralgia can be resected safely using the anterior transpetrosal approach allowing rapid resolution of symptoms. This review of operative nuances provides a guide for neurosurgeons to provide safe surgical resection., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The impact of surgeon specialty on outcomes following carotid endarterectomy (CEA) has been widely debated within the literature. Previous studies on this subject are often limited by small sample sizes, single-intuition designs, variability in patients and procedures, and potential confounding factors such as institution type and volume., Objective: To identify similarities and differences between surgeon specialties in postoperative stroke and mortality rates for patients undergoing unilateral CEAs by utilizing a large, multicenter prospective database., Methods: We utilized a large national prospective database (National Surgical Quality Inpatient database) and investigated all patients with a 1-sided, surgically naïve CEA, performed by either a general, vascular, cardiothoracic, or neurological surgeon. We employed a logistic regression analysis to control for the most salient variables identified via univariate analysis. Our primary outcomes were all-cause mortality and stroke., Results: There were 42 369 patients included across all specialties. Patients from each specialty were similar in demographics but varied in medical history. Multivariate analysis demonstrated that among the specialties only general surgeons had significantly greater postoperative stroke rates (2.3%) when compared to vascular surgeons (1.5%; P = .003, odds ratio [OR] 1.574, confidence interval [CI]: 1.168-2.121). In contrast, surgical specialty was not a significant risk factor for 30-d postoperative mortality (0% in cardiothoracic surgeons; 0.8% in vascular surgeons; 1.1% in general surgeons; 1.8% in neurosurgeons; Cardiothoracic surgeons: P = .995, OR: 0 [no incidences of mortality]; neurosurgeon: P = .118, OR: 0.2057, CI: 0.833-2.057; general surgeon P = .210, OR: 1.326, CI: 1.853-2.062). Most secondary outcomes (myocardial infarction, infection, reoperation, pneumonia) were similar between specialties (P = .339-.816). However, length of stay (P < .001), operative duration (P < .001), incidence of venous thromboembolism (P < .001), and the postoperative requirement for a ventilator greater than 48 h (P = .004) were all the greatest among neurosurgeons., Conclusion: Multidisciplinary approaches with improved communication among surgical specialties may enhance patient management and improve success after CEA. Though there were differences in postoperative stroke and other secondary outcomes, no differences were observed among specialties in mortality after unilateral CEA in more than 40 000 patients., (Copyright © 2016 by the Congress of Neurological Surgeons)

We report on a unique case of a giant, recurrent, supratentorial neurenteric cyst causing intractable eplipsy. Following resection, the patient developed a delayed reactive cerebritis with focal edema and worsened seizures that fully resolved with medical management. At last follow-up, over 18 months later, the patient has no evidence for cyst recurrence and remains seizure-free. we conclude that complete resection of these lesions not only requires fenestration, but also microsurgical stripping of the cyst wall. Moreover, post-operative management inclues monitoring for worsened seizures as a consequence of intracranial exposure to the cystic contents and subsequent reactive cerebritis.