Citations

Abstract Chiari malformation is a relatively rare condition involving herniation of the brain out of the skull and into the spinal canal. The purpose of this review was to identify top contributors to the world of Chiari research, as well as to highlight the publications which have shaped our perception of this condition.We performed a search of the Web of Science between the years 1900 and 2021 using the terms “Chiari I malformation”, “Arnold Chiari malformation”, “Chiari II malformation”, “Chiari malformation type 1”, and “Chiari malformation type 2”. After screening for duplicates and assessing for relevance using two independent reviewers, the top 100 most frequently cited articles were collected and sorted. These articles were published between the years 1938 and 2015 and were cited 145.7 times on average, ranging from 79 to 724 citations per article. Authored by Milhorat et al., the 1999 Neurosurgery article “Chiari I Malformation Redefined: Clinical and Radiographic Findings for 364 Symptomatic Patients” received most citations (724 citations). Journal of Neurosurgery contributed the most articles to the top-100 with 21 publications. The University of California system accounted for the most articles by institution (8 of 100) and the USA was the highest contributing country (62%). In this study, we identified and analyzed the most cited articles on Chiari malformations to gain a better understanding of the publications contributing our knowledge of this disorder. This analysis serves both as a way of gauging the current state of research and of recognizing gaps where further research is necessary.

OBJECTIVE Improper embryological development of the clivus, a bony structure that comprises part of the skull base, can lead to a clival canal defect. Previously thought to be a benign condition, clival canals have been reported to be associated with meningitis and meningoceles. In this review, the authors sought to present an unpublished case of a patient with a clival canal defect associated with meningitis and to evaluate all other reported cases. METHODS In October 2020, a search of PubMed, Web of Science, and Scopus was conducted to identify all cases of clival canals reported from January 1, 1980, through October 31, 2020. RESULTS Including the case presented herein, 13 cases of clival canals, 11 in children (84.6%) and 2 in adults (15.4%), have been identified. Of the pediatric patients, 5 (45.5%) had an associated meningocele, and 8 (72.7%) had meningitis. Nine of the 13 patients (69.2%) had defects that were treated surgically, 5 (38.5%) by a transnasal approach and 4 (30.8%) by a transoral approach. Two patients (15.4%) were treated with drainage and antibiotics, 1 patient (7.7%) was treated solely with antibiotics, and 1 patient (7.7%) was not treated. In the literature review, 8 reports of clival canals were found to be associated with meningitis, further contributing to the notion that the clival canal may be an overlooked source of recurrent infection. In several of these cases, surgical repair of the lesion was curative, thus preventing continued episodes of meningitis. CONCLUSIONS When a patient has recurrent meningitis with no clear cause, taking a closer look at clival anatomy is recommended. In addition, if a clival canal defect has been identified, surgical repair should be considered a safe and effective primary treatment option.

OBJECTIVE Due to their deep and medial location, range of seizure semiologies, and poor localization on ictal electroencephalography (EEG), cingulate gyrus seizures can be difficult to diagnose and treat. The aim of this study was to review the available evidence on postoperative outcomes after cingulate epilepsy surgery. METHODS A comprehensive literature search of the PubMed/MEDLINE, Ovid Embase, Ovid Scopus, and Cochrane Library databases was conducted to identify studies that investigated postoperative outcomes of patients with cingulate epilepsy. Seizure freedom at the last follow-up (at least 12 months) was the primary endpoint. The literature search was supplemented by the authors’ institutional series (4 patients). RESULTS Twenty-one studies were identified, yielding a total of 105 patients (68 with lesional epilepsy [65%]). Median age at surgery was 23 years, and 56% of patients were male. Median epilepsy duration was 7.5 years. Invasive EEG recording was performed on 69% of patients (53% of patients with lesional epilepsy and 97% of those with nonlesional epilepsy, p < 0.001). The most commonly resected region was the anterior cingulate (55%), followed by the posterior (17%) and middle (14%) cingulate. Lesionectomy alone was performed in 9% of patients. Additional extracingulate treatment was performed in 54% of patients (53% of patients with lesional epilepsy vs 57% of those with nonlesional epilepsy, p = 0.87). The most common pathology was cortical dysplasia (54%), followed by low-grade neoplasm (29%) and gliosis (8%). Seizure freedom was noted in 72% of patients (median follow-up 24 months). A neurological deficit was noted in 27% of patients (24% had temporary deficit), with the most common deficit being motor weakness (13%) followed by supplementary motor area syndrome (9.5%). Univariate survival analysis revealed significantly greater probability of seizure freedom in patients with lesional epilepsy (p = 0.015, log-rank test). CONCLUSIONS Surgical treatment of drug-resistant focal epilepsy originating from the cingulate gyrus is safe, leads to low rates of permanent adverse effects, and leads to high rates of long-term seizure freedom in carefully selected patients. These data may serve as a benchmark for surgical counseling of patients with cingulate epilepsy.

OBJECTIVE The prevalence of epilepsy in the older adult population is increasing. While surgical intervention in younger patients is supported by level I evidence, the safety and efficacy of epilepsy surgery in older individuals is less well established. The aim of this study was to evaluate seizure freedom rates and surgical outcomes in older epilepsy patients. METHODS The authors’ institutional electronic database was queried for patients older than 50 who had undergone epilepsy surgery during 2002–2018. Cases were grouped into 50–59, 60–69, and 70+ years old. Seizure freedom at the last follow-up constituted the primary outcome of interest. The institutional analysis was supplemented by a literature review and meta-analysis (random effects model) of all published studies on this topic as well as by an analysis of complication rates, mortality rates, and cost data from a nationwide administrative database (Vizient Inc., years 2016–2019). RESULTS A total of 73 patients (n = 16 for 50–59 years, n = 47 for 60–69, and n = 10 for 70+) were treated at the authors’ institution. The median age was 63 years, and 66% of the patients were female. At a median follow-up of 24 months, seizure freedom was 73% for the overall cohort, 63% for the 50–59 group, 77% for the 60–69 group, and 70% for the 70+ group. The literature search identified 15 additional retrospective studies (474 cases). Temporal lobectomy was the most commonly performed procedure (73%), and mesial temporal sclerosis was the most common pathology (52%), followed by nonspecific gliosis (19%). The pooled mean follow-up was 39 months (range 6–114.8 months) with a pooled seizure freedom rate of 65% (95% CI 59%–72%). On multivariable meta-regression analysis, an older mean age at surgery (coefficient [coeff] 2.1, 95% CI 1.1–3.1, p < 0.001) and the presence of mesial temporal sclerosis (coeff 0.3, 95% CI 0.1–0.6, p = 0.015) were the most important predictors of seizure freedom. Finally, analysis of the Vizient database revealed mortality rates of 0.5%, 1.1%, and 9.6%; complication rates of 7.1%, 10.1%, and 17.3%; and mean hospital costs of $31,977, $34,586, and $40,153 for patients aged 50–59, 60–69, and 70+ years, respectively. CONCLUSIONS While seizure-free outcomes of epilepsy surgery are excellent, there is an expected increase in morbidity and mortality with increasing age. Findings in this study on the safety and efficacy of epilepsy surgery in the older population may serve as a useful guide during preoperative decision-making and patient counseling.

Background: Radial tunnel syndrome arises due to compression of the radial nerve through the radial tunnel.[1,5] The radial nerve divides into superficial and deep branches in the forearm. The deep branch travels posteriorly through the heads of the supinator where compression commonly occurs.[3,9,7] This syndrome results in pain in the hand and forearm with no motor weakness.[8] This condition can be treated conservatively with splinting and anti-inflammatory medication.[2,4,6] For cases of refractory radial tunnel syndrome, surgical management can be considered. Herein, we have presented a step-by-step video guide on how to perform a radial nerve decompression with a review of the relevant anatomy and surgical considerations. Case Description: A 68-year-old right-handed woman presented to the Mayo Clinic (Scottsdale, AZ) with the right elbow pain which radiated to the forearm causing significant difficulties with daily tasks. She had been dealing with worsening symptoms for 4 months. The patient’s history of gardening and clinical presentation allowed for diagnosis of radial tunnel syndrome. After conservative measures failed and other differential diagnoses were excluded, surgical decompression was recommended to treat her symptoms. The patient’s right arm was marked preoperatively between the brachioradialis and extensor carpi radialis longus (ECRL) muscles. The posterior cutaneous nerve of the forearm was identified which allowed for the determination of the interval between the brachioradialis and ECRL. Separation of the two muscles allowed for the identification of the radial sensory nerve. A nerve stimulator was used to confirm the sensory nature of this nerve. The nerve to the extensor carpi radialis brevis (ECRB) was identified and retracted with a vessel loop. Dorsal to the nerve to the ECRB is the posterior interosseous nerve (PIN), which was identified and retracted with a vessel loop. The fascia of the ECRB was divided both longitudinally and transversely and the supinator below was identified. The supinator muscle was carefully divided to further decompress the PIN. Informed consent for publication of this material was obtained from the patient. Conclusion: The patient tolerated the procedure well and reported significantly reduced pain at 7-month follow-up. To the best of our knowledge, video tutorials on this procedure have not been published. This video can serve as an educational guide for peripheral nerve specialists dealing with similar lesions.

OBJECTIVE Insular lobe epilepsy is a challenging condition to diagnose and treat. Due to anatomical intricacy and proximity to eloquent brain regions, resection of epileptic foci in that region can be associated with significant postoperative morbidity. The aim of this study was to review available evidence on postoperative outcomes following insular epilepsy surgery. METHODS A comprehensive literature search (PubMed/MEDLINE, Scopus, Cochrane) was conducted for studies investigating the postoperative outcomes for seizures originating in the insula. Seizure freedom at last follow-up (at least 12 months) comprised the primary endpoint. The authors also present their institutional experience with 8 patients (4 pediatric, 4 adult). RESULTS A total of 19 studies with 204 cases (90 pediatric, 114 adult) were identified. The median age at surgery was 23 years, and 48% were males. The median epilepsy duration was 8 years, and 17% of patients had undergone prior epilepsy surgery. Epilepsy was lesional in 67%. The most common approach was transsylvian (60%). The most commonly resected area was the anterior insular region (n = 42, 21%), whereas radical insulectomy was performed in 13% of cases (n = 27). The most common pathology was cortical dysplasia (n = 68, 51%), followed by low-grade neoplasm (n = 16, 12%). In the literature, seizure freedom was noted in 60% of pediatric and 69% of adult patients at a median follow-up of 29 months (75% and 50%, respectively, in the current series). A neurological deficit occurred in 43% of cases (10% permanent), with extremity paresis comprising the most common deficit (n = 35, 21%), followed by facial paresis (n = 32, 19%). Language deficits were more common in left-sided approaches (24% vs 2%, p < 0.001). Univariate analysis for seizure freedom revealed a significantly higher proportion of patients with lesional epilepsy among those with at least 12 months of follow-up (77% vs 59%, p = 0.032). CONCLUSIONS These findings may serve as a benchmark when tailoring decision-making for insular epilepsy, and may assist surgeons in their preoperative discussions with patients. Although seizure freedom rates are quite high with insular epilepsy treatment, the associated morbidity needs to be weighed against the potential for seizure freedom.

Abstract Adolescent idiopathic scoliosis (AIS) is an abnormal lateral curvature of the spine that arises during the pubescent growth spurt. AIS mainly affects females in the age group of 10 to 16 yr, with a prevalence of about 1% to 3% in the at-risk population. 1 Treatment options vary depending on disease presentation and severity. Mild curvature mainly requires periodic observation for disease progression, whereas more moderate curvature can necessitate bracing or corrective surgery. 2 Here, we present the use of a temporary rod and neuroimaging for the correction of Lenke type 1 spinal curvature in an AIS patient. An inferior facetectomy is performed, and a Lenke probe is used for entry into the pedicle and vertebral body. The channel is sounded before and after tapping to check for adequate walls prior to insertion of the pedicle screw. The ARTIS pheno is brought into the field, which uses fluoroscopy to create a 3-dimensional (3D) representation of the instrumentation within the spine. A temporary rod is placed in the concavity, and a combination of corrective techniques, including a rod roll, apical translation, and reduction, is performed to bring up the concavity, derotate the spine, and translate the spine. The permanent rod is then placed in the convexity, and compression is performed to bring down the scapular prominence. The temporary rod is then removed, and a final rod is placed to complete the 3D correction. The patient consented to the procedure, and an informed written consent was obtained from the patient to use her photographs and video recordings for publication.