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1. Lakomkin N, Stannard B, Fogelson JL, et al. Comparison of surgical invasiveness and morbidity of adult spinal deformity surgery to other major operations. Spine J 2021;21:17 84–92. Available from: https://doi.org/10.1016/j.spinee.2021.07.013

Adult spinal deformity (ASD) surgery treats a variety of debilitating spinal conditions including degenerative scoliosis, idiopathic scoliosis, kyphoscoliosis, and flat-back syndrome, among others. Although ASD surgery leads to excellent postoperative outcomes, numerous studies have identified rates of perioperative complications at approximately 50% to 70%, along with large incidence of intraoperative transfusions, prolonged hospital length of stay (LOS), and mortality.

A prospective surgical registry was used to identify all patients undergoing ASD surgery involving ≥ 7 segments. Seventeen additional procedures were included: coronary artery bypass grafting (CABG), pancreatectomy, and esophagectomy, among others. Perioperative factors (operative time, transfusions, ventilation) and complications were collected and combined with a previously validated Postoperative Morbidity Survey to create a Surgical Invasiveness and Morbidity Score (SIMS).

A total of 1,245,282 surgical patients were included, 4,656 of which underwent ASD surgery. After multiple regression modeling controlling for patient demographics and comorbidities, ASD surgery ranked fourth in Surgical Invasiveness and Morbidity Score. ASD surgery had a significantly greater SIMS than 13 other major procedures including 6th esophagectomy, 8th pancreatectomy, 11th craniotomy for tumor, and 12th sacral chordoma resection.

Among the 18 surgical procedures, ASD surgery ranked third in operative duration (351 min), surpassed only by microsurgical free flap (486 min) and esophagectomy (354 min). ASD ranked fourth in the proportion of patients requiring transfusion (50.9%), with only CABG (64.1%), open AAA repair (61.6%), and MVR (57.1%) with a greater incidence.

These data suggest that the surgical invasiveness and morbidity of ASD correction may exceed some of the largest and traditionally highest-risk surgical operations. These relationships held true despite the fact that ASD patients presented with a significantly decreased comorbidity burden when compared to their counterparts. Indeed, among the procedures with SIMS that exceeded ASD (CABG, AAA repair, cystectomy), all three are known to be associated with inherently sicker patients.

1 figure, 5 tables, no imaging

2. Maiese A, Manetti AC, Bosetti C, et al. SARS-CoV-2 and the brain: a review of the current knowledge on neuropathology in COVID-19. Brain Pathol 2021;31:1–17

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the new coronavirus responsible for the pandemic disease, is able to affect the central nervous system. Compared with its well-known pulmonary tropism and respiratory complications, little has been studied about SARS-CoV-2 neurotropism and pathogenesis of its neurological manifestations, but also about postmortem histopathological findings in the CNS of patients who died from COVID-19 (coronavirus disease 2019). The authors present a systematic review, carried out according to the Preferred Reporting Items for Systematic Review standards, of the neuropathological features of COVID-19. They found 21 scientific papers, the majority of which refer to postmortem examinations; the total amount of cases is 197. Hypoxic changes are the most frequently reported alteration of brain tissue, followed by ischemic and hemorrhagic lesions and reactive astrogliosis and microgliosis. These findings do not seem to be specific to SARS-CoV- 2 infection, they are more likely because of systemic inflammation and coagulopathy caused by COVID-19.

Tables 2 in the paper tabulates the most common features from the literature. The most common features were microgliosis and microglia activation, both with or without microglia nodules (37.6%), followed by hypoxic changes (29.4%) and astrogliosis (26.4%). Inflammatory infiltrates were present in 15.7% of cases, considering the parenchymal and perivascular localization, while leptomeningeal inflammation and infiltrates were observed in 5.6% of cases. Inflammation was mainly maintained by macrophages and T-lymphocytes. CNS samples showed microthrombi in 21 cases up to 197 (10.6%) and large ischemic lesions in 30 (15.2%). On the other hand, micro-and perivascular hemorrhages were described in 12.2% of cases, while focal hemorrhagic lesions in 6.6% of cases. Concerning olfactory bulb involvement, the presence of SARS-CoV-2 or inflammatory features of this part of the CNS was observed in 57 cases (28.9%).

2 large tables, and 2 figures, all pathology

3. Reid LB, Martínez-Heras E, Manjón JV, et al. Fully automated delineation of the optic radiation for surgical planning using clinically feasible sequences. Hum Brain Mapp 2021;42:59 11–26

Quadrantanopia caused by inadvertent severing of Meyer’s Loop of the optic radiation is a well-recognized complication of temporal lobectomy for conditions such as epilepsy. Dissection studies indicate that the anterior extent of Meyer’s Loop varies considerably between individuals. Quantifying this for individual patients is thus an important step to improve the safety profile of temporal lobectomies. Previous attempts to delineate Meyer’s Loop using diffusion MRI tractography have had difficulty estimating its full anterior extent, required manual ROI placement, and/or relied on advanced diffusion sequences that cannot be acquired routinely in most clinics. In this article the authors present CONSULT: a pipeline that can delineate the optic radiation from raw DICOM data in a completely automated way via a combination of robust preprocessing, segmentation, and alignment stages, plus simple improvements that bolster the efficiency and reliability of standard tractography. They tested CONSULT on 696 scans of predominantly healthy participants (539 unique brains), including both advanced acquisitions and simpler acquisitions that could be acquired in clinically acceptable timeframes. Delineations completed without error in 99.4% of the scans. The distance between Meyer’s Loop and the temporal pole closely matched both averages and ranges reported in dissection studies for all tested sequences. Median scan-rescan error of this distance was 1 mm. When tested on two participants with considerable pathology, delineations were successful and realistic. Through this, they demonstrate not only how to identify Meyer’s Loop with clinically feasible sequences, but also that this can be achieved without fundamental changes to tractography algorithms or complex post-processing methods.

2 tables, 8 figures with MR images

4. Nagahama Y, Zervos TM, Murata KK, et al. Real-world preliminary experience with responsive neurostimulation in pediatric epilepsy: a multicenter retrospective observational study. Neurosurgery 2021;89:99 7–1004

Patients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients.

Of 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved seizure freedom, 4 (13%) achieved ≥90% seizure reduction, 13 (41%) had ≥50% reduction, 8 (25%) had <50% reduction, and 5 (16%) experienced no improvement. The average follow-up duration was 1.7 yr (median 1.8 yr, range 0.3-4.8 yr). There was no statistically significant difference for seizure reduction and complications between children and young adults in this cohort or between this cohort and the adult literature.

Considering this procedure invariably involves a craniectomy for device implantation, the benefits and potential harm based on the variable skull development in individual patients should be considered. Children experience rapid skull growth within the first 2 yr and reach ∼90% of the adult skull volume by 7 yr. There were 2 patients under 7 yr at the time of RNS implantation included in this study. The youngest was 3 yr of age at the time of RNS implantation, which is the youngest reported patient to undergo RNS implantation.

Open sutures in infants would be a contraindication due to the small head size and the difficulty in securing the device. Although skull immaturity may be considered a relative contraindication in very young patients, this must be determined on a case-by-case basis, given the variability in skull growth and skull thickness in individual patients (eg, 4-m