Anterior clinoid meningiomas: surgical results and proposed scoring system to predict visual outcomes

OBJECTIVE

The authors report a single-surgeon experience with anterior clinoid meningiomas (ACMs) and propose a novel scoring system to predict visual outcomes based on preoperative risk factors.

METHODS

A cohort study of all ACMs that were surgically treated by a single surgeon between 2003 and 2021 was performed. Visual function was assessed by an ophthalmologist pre- and postoperatively. Based on the combination of visual fields and visual acuity, 4 visual grades were described. Favorable visual outcomes were defined as mild visual deficit or intact vision postoperatively. Unfavorable visual outcomes were defined as a severe or moderate visual deficit. Predictors of unfavorable visual outcomes were identified using multivariable logistic regression analysis. A scoring system was then created using the resulting β coefficient. A receiver operating characteristic curve analysis was performed to identify a cutoff point on the grading score for stratifying patients at risk for unfavorable visual outcomes.

RESULTS

Fifty-two patients met all inclusion criteria. Twenty-five (48%) patients presented with intact vision, and 27 (51%) presented with some visual dysfunction. Postoperative favorable visual outcomes were achieved in 39 patients (75%). Among the 27 patients presenting with visual dysfunction, 14 (52%) experienced improvement after surgery. No new visual deficits were observed among the 25 patients with intact vision at baseline. Nine patients (17%) had a reversible complication. Multivariable analysis showed that severe preoperative visual deficit (OR 13.03, 95% CI 2.64-64.39; p = 0.002), radiographic evidence of optic nerve (ON) encasement (OR 4.20, 95% CI 1.06-16.61; p = 0.04), intraoperative evidence of ON invasion (OR 17.31, 95% CI 2.91-102.86; p = 0.002), an average ganglion cell layer thickness of ≤ 70 µm (OR 21.54, 95% CI 2.94-159.04; p = 0.003), and an average retinal nerve fiber layer thickness of ≤ 80 µm (OR 13.68, 95% CI 1.91-98.00; p = 0.009) were associated with unfavorable visual outcome. The predictive score included the following factors: abnormal optical coherence tomography (OCT) findings, radiographic evidence of ON encasement by the tumor, and severe preoperative visual deficit. A score ≥ 4 of 6 points was demonstrated to be the cutoff associated with unfavorable visual outcome, with a sensitivity of 80%, specificity of 88%, positive predictive value of 80%, negative predictive value of 88%, and area under the curve of 0.847 (95% CI 0.674-1.0; p = 0.003).

CONCLUSIONS

The authors have designed a practical and novel scoring system to predict visual outcomes in patients with ACMs. This scoring system may guide preoperative discussions with patients and timely surgical intervention to yield optimal visual function outcomes. Although most patients have excellent neurosurgical outcomes, severe baseline visual deficits, ON encasement, and characteristic OCT abnormalities are associated with unfavorable visual function after ACM resection.

Expanding the reach of the trans-middle cerebellar peduncle approach: pontine cavernous malformations, tissue transgression beyond the safe entry zone, and the invisible triangle

OBJECTIVE

In the authors' microsurgical experience, the trans-middle cerebellar peduncle (MCP) approach to the lateral and central pons has been the most common approach to brainstem cavernous malformations (BSCMs). This approach through a well-tolerated safe entry zone (SEZ) allows a wide vertical or posterior trajectory, reaching pontine lesions extending into the midbrain, medulla, and pontine tegmentum. Better understanding of the relationships among lesion location, surgical trajectory, and long-term clinical outcomes could determine areas of safe passage.

METHODS

A single-surgeon cohort study of all primary trans-MCP BSCM resections was conducted from July 1, 2017, to June 30, 2021. Preoperative and postoperative MR images were independently reviewed by 3 investigators blinded to the intervention, using a standardized rubric to define BSCM regions of interest (ROIs) involved with a lesion or microsurgical tract. Statistical testing, including the chi-square test with the Bonferroni correction, logistic regression, and structural equation modeling, was performed to analyze relationships between ROIs and clinical outcomes.

RESULTS

Thirty-one patients underwent primary trans-MCP BSCM resection during the study period. The median age was 50 years (IQR 24-49 years); 19 (61%) patients were female, and 12 (39%) were male. Seven (23%) patients had familial cavernous malformation syndromes. The median follow-up was 9 months (range 6-37 months). At the last follow-up, composite neurological outcomes were favorable: 22 (71%) patients had 0 (n = 12, 39%) or 1 (n = 10, 32%) major persistent deficit, 5 patients (16%) had 2 deficits, 2 (7%) had 3 deficits, and 1 patient each (3%) had 4 or 6 deficits. Unfavorable composite outcomes were significantly associated with lesions (OR 7.14, p = 0.04) or surgical tracts (OR 12.18, p < 0.001) extending from the superior cerebellar peduncle (SCP) into the contralateral medial midbrain. The ipsilateral dorsal pons was the most frequently implicated ROI involving a surgical tract and the development of new postoperative deficits. This region involved the rhomboid pontine territory and transgression of the pontine tegmentum (OR 7.53, p < 0.001). Structural equation modeling supported medial midbrain and pontine tegmentum transgression as the primary drivers of morbidity.

CONCLUSIONS

Trans-MCP resection is a safe and effective treatment for BSCMs, including lesions with marked superior or inferior ipsilateral extension. Two trajectories are associated with increased neurological risk: first, a superomedial trajectory to lesions extending into the midbrain that transgresses the SCP, its decussation, or both; and second, a posteromedial trajectory to lesions extending into the pontine tegmentum. The corticospinal tract, SCP, and pontine tegmentum form an invisible triangle within the pontine white matter tolerant of transgression. When the surgeon works within this triangle, most deep pontine BSCMs, including large lesions, those with contralateral or posterior extension, and others extending into the midbrain and medulla, can be resected safely with the trans-MCP approach.

Recent Trends in Successful Neurosurgery Resident Matriculation: A Retrospective and Bibliometric Analysis

BACKGROUND

Prior literature has demonstrated barriers to successful residency matching, including sex, medical school background, and international medical graduate status. Our aim is to characterize the recent trends in successfully-matched residents, with particular attention to geography and academic productivity.

METHODS

Resident information, including demographics and educational background, was gathered from program websites. Bibliometric analysis focused on PubMed publications from the top neurosurgery journals. A top 20 medical school was defined using the US News Rankings for research in 2022. Regression analyses were performed to explore the associations between total and first-author publications and other relevant factors, correcting for graduate studies.

RESULTS

A total of 114 institutions and 946 residents were included in the final analysis. Of the 845 with medical school information, 62 (7.3%) completed medical school internationally and 181 of 783 (23.1%) came from a top 20 medical school. Male residents had a higher proportion of residents with international undergraduate and international medical school degrees when compared to female residents [32 (7.5%) vs. 4 (2.4%), P = 0.021; 52 (8.6%) vs. 10 (4.2%), P = 0.026; respectively]. The multivariate regression analysis demonstrated a significant increase in publications for international medical school graduates (B = 8.3, P < 0.001), top tier medical school graduate (B = 1.3, P = 0.022), and male sex (B = 1.20, P = 0.019) for total number of publications.

CONCLUSIONS

Geographical factors, reported sex, and graduation status have influenced how resident candidates are perceived. Understanding these trends is vital for future resident matching. Addressing gender and educational diversity is essential to foster inclusivity and research-driven environments in neurosurgery residency programs.

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review

BACKGROUND AND OBJECTIVES

Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse.

METHODS

A single-institution cohort study and systematic literature review of LCNS were performed.

RESULTS

Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients.

CONCLUSION

Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control-particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

Acute Macrocystic Thoracic Schwannoma: Systematic Review and Illustrative Case Example

BACKGROUND

Schwannomas are benign peripheral nerve sheath tumors arising from myelinating Schwann cells. Although macrocystic changes are regularly encountered in schwannoma variants such as vestibular nerve tumors, they are exceedingly rare among spinal neoplasms.

METHODS

Case report and systematic review of 4 databases (Ovid Medline, PubMed, Science Direct, and SCOPUS) from inception to present. All peer-reviewed publications reporting intradural cystic thoracic schwannoma were included.

RESULTS

We identified 8 publications documenting 9 cases of cystic thoracic schwannoma. Four were female, 5 male; median age was 41 years (range, 27-80). Presentations ranged from incidental to pain, sensory changes, lower extremity paresis, or bowel/bladder dysfunction. Characteristic radiographic findings included T1 hypointensity, T2 hyperintensity, and cord effacement or compression. The present case followed a similar pattern: a 52-year-old male presented with worsening bilateral lower extremity weakness, low back pain, and gait dysfunction, worsening over 3 days. Examination also revealed decreased left lower extremity sensation. Imaging identified a well-delineated intradural, extramedullary macrocystic extending over T7-T10. The patient underwent a laminectomy resulting in complete tumor resection and restoration of intact neurologic function. Final pathology confirmed benign cystic schwannoma.

CONCLUSIONS

Macrocystic thoracic schwannomas are exceedingly rare and lack a comprehensive scheme for clinical classification of their natural history and pathogenesis. We report the 10th case of such a schwannoma, and the first associated systematic review. Although macrocystic thoracic schwannomas are not frequently encountered, accurate diagnosis and appropriate neurosurgical treatment is critical in these vulnerable patients, given the opportunity for excellent functional outcomes following neurosurgical treatment.

Genetically Distinct Oligosarcoma Arising from Oligodendroglioma: Systematic Review & Illustrative Case Example

BACKGROUND

Oligosarcoma is a rare central nervous system (CNS) neoplasm that may arise following oligodendroglioma resection, which demonstrates a unique genetic profile and aggressive clinical phenotype. We present a systematic review and illustrative case example emphasizing the clinical and prognostic features of this unusual and unfavorable neuro-oncologic disease.

METHODS

Systematic literature review and illustrative case report.

RESULTS

A 41-year-old man who had undergone 2 neurosurgical resections for a World Health Organization grade II oligodendroglioma (Ki-67 = 5-10%, 1p/19q codeleted, IDH2 mutated), without adjuvant chemoradiation, presented with seizures seven years after resection. An extra-axial mass was identified adjacent to the resection cavity, in which gross total resection was achieved. Pathology confirmed World Health Organization grade IV oligosarcoma (Ki-67 = 20%). Adjuvant chemoradiation was initiated, with disease control observed over 6 months of follow-up. Seven publications met inclusion criteria. Oligosarcoma has been confirmed in 36 lesions, arising in 35 patients; 5 were primary oligosarcoma, while 31 occurred in the setting of prior resected oligodendroglioma or oligoastrocytoma. Features shared by these lesions include regain of H3K27me3 expression, 1p/19q codeletion, homozygous deletion of CDKN2A/B, loss of 6q, loss of NF1 and YAP1, and attenuation of CpG island methylator. Median survival after oligosarcoma diagnosis was 1.3 years (range, 0-5.2; n = 35).

CONCLUSIONS

Oligosarcoma is a prognostically unfavorable CNS neoplasm with characteristic imaging and pathologic features, and a strong association with previously resected oligodendroglioma. Aggressive treatment is recommended, including gross total resection and adjuvant chemoradiation. Further study is required to define optimal treatment protocol for this CNS malignancy.

Sex differences in patients with and without high-risk factors associated with aneurysmal subarachnoid hemorrhage

BACKGROUND

Controversy remains regarding the appropriate screening for intracranial aneurysms or for the treatment of aneurysmal subarachnoid hemorrhage (aSAH) for patients without known high-risk factors for rupture. This study aimed to assess how sex affects both aSAH presentation and outcomes for aSAH treatment.

METHOD

A retrospective cohort study was conducted of all patients treated at a single institution for an aSAH during a 12-year period (August 1, 2007-July 31, 2019). An analysis of women with and without high-risk factors was performed, including a propensity adjustment for a poor neurologic outcome (modified Rankin Scale [mRS] score > 2) at follow-up.

RESULTS

Data from 1014 patients were analyzed (69% [n = 703] women). Women were significantly older than men (mean ± SD, 56.6 ± 14.1 years vs 53.4 ± 14.2 years, p < 0.001). A significantly lower percentage of women than men had a history of tobacco use (36.6% [n = 257] vs 46% [n = 143], p = 0.005). A significantly higher percentage of women than men had no high-risk factors for aSAH (10% [n = 70] vs 5% [n = 16], p = 0.01). The percentage of women with an mRS score > 2 at the last follow-up was significantly lower among those without high-risk factors (34%, 24/70) versus those with high-risk factors (53%, 334/633) (p = 0.004). Subsequent propensity-adjusted analysis (adjusted for age, Hunt and Hess grade, and Fisher grade) found no statistically significant difference in the odds of a poor outcome for women with or without high-risk factors for aSAH (OR = 0.7, 95% CI = 0.4-1.2, p = 0.18).

CONCLUSIONS

A higher percentage of women versus men with aSAH had no known high-risk factors for rupture, supporting more aggressive screening and management of women with unruptured aneurysms.

Microsurgical Resection of a Lateral Pontine Arteriovenous Malformation Masquerading as a Cavernous Malformation: 2-Dimensional Operative Video

Although cavernous malformations (CMs) often demonstrate characteristic T2 heterogeneity and gadolinium enhancement, whereas arteriovenous malformations (AVMs) appear as tangles of T2 hypointense flow voids, small lesions in deep locations may have equivocal features on preoperative imaging.1-4 This video presents an unusual case of a lateral pontine AVM masquerading as a CM. The patient presented with sudden-onset headache, dizziness, double vision, and left facial numbness. Diagnostic imaging findings suggested a hemorrhagic left lateral pontine mass lesion, most consistent with brainstem CM. Resection through a left extended retrosigmoid craniotomy was recommended. Patient consent was obtained. During dissection, a prominent petrosal vein tributary was noted to be arterialized, which was concerning for AVM. Indocyanine green videoangiography (ICG-VA) was performed to confirm the diagnosis, and the intraoperative plan was dynamically adjusted in accordance with the principles of AVM resection. The small superficial feeding arteries were identified and disconnected, and the nidus was dissected circumferentially with the pial resection technique. After dearterialization, the draining petrosal vein was noted to darken, and repeat ICG-VA confirmed complete occlusion of the AVM without residual shunting. The patient recovered well, with no neurological deficits, and postoperative angiography confirmed complete resection of the Spetzler-Martin grade III AVM. Key learning points for this unusual case include the importance of dynamic interpretation of intraoperative findings, openness to alterations of the surgical plan when integrating new diagnostic information, and the integration of ICG-VA as a critical tool for differentiating CMs and AVMs during microsurgical resection. Images in Surgical Video © 2024 Barrow Neurological Institute. Used with permission.

Prediction of Surgical Outcomes in Normal Pressure Hydrocephalus by MR Elastography

BACKGROUND AND PURPOSE

Normal pressure hydrocephalus is a treatable cause of dementia associated with distinct mechanical property signatures in the brain as measured by MR elastography. In this study, we tested the hypothesis that specific anatomic features of normal pressure hydrocephalus are associated with unique mechanical property alterations. Then, we tested the hypothesis that summary measures of these mechanical signatures can be used to predict clinical outcomes.

MATERIALS AND METHODS

MR elastography and structural imaging were performed in 128 patients with suspected normal pressure hydrocephalus and 44 control participants. Patients were categorized into 4 subgroups based on their anatomic features. Surgery outcome was acquired for 68 patients. Voxelwise modeling was performed to detect regions with significantly different mechanical properties between each group. Mechanical signatures were summarized using pattern analysis and were used as features to train classification models and predict shunt outcomes for 2 sets of feature spaces: a limited 2D feature space that included the most common features found in normal pressure hydrocephalus and an expanded 20-dimensional (20D) feature space that included features from all 4 morphologic subgroups.

RESULTS

Both the 2D and 20D classifiers performed significantly better than chance for predicting clinical outcomes with estimated areas under the receiver operating characteristic curve of 0.66 and 0.77, respectively (P < .05, permutation test). The 20D classifier significantly improved the diagnostic OR and positive predictive value compared with the 2D classifier (P < .05, permutation test).

CONCLUSIONS

MR elastography provides further insight into mechanical alterations in the normal pressure hydrocephalus brain and is a promising, noninvasive method for predicting surgical outcomes in patients with normal pressure hydrocephalus.

Modafinil Therapy and Mental Status Following Aneurysmal Subarachnoid Hemorrhage: Comprehensive Stroke Center Analysis

BACKGROUND

Disorders of consciousness impair early recovery after aneurysmal subarachnoid hemorrhage (aSAH). Modafinil, a wakefulness-promoting agent, is efficacious for treating fatigue in stroke survivors, but data pertaining to its use in the acute setting are scarce. This study sought to assess the effects of modafinil use on mental status after aSAH.

METHODS

Modafinil timing and dosage, neurological examination, intubation status, and physical and occupational therapy participation were documented. Repeated-measures paired tests were used for a before-after analysis of modafinil recipients. Propensity score matching (1:1 nearest neighbor) for modafinil and no-modafinil cohorts was used to compare outcomes.

RESULTS

Modafinil (100-200 mg/day) was administered to 21% (88/422) of aSAH patients for a median (IQR) duration of 10.5 (4-16) days and initiated 14 (7-17) days after aSAH. Improvement in mentation (alertness, orientation, or Glasgow Coma Scale score) was documented in 87.5% (77/88) of modafinil recipients within 72 hours and 86.4% (76/88) at discharge. Of 37 intubated patients, 10 (27%) were extubated within 72 hours after modafinil initiation. Physical and occupational therapy teams noted increased alertness or participation in 47 of 56 modafinil patients (83.9%). After propensity score matching for baseline covariates, the modafinil cohort had a greater mean (SD) change in Glasgow Coma Scale score than the no-modafinil cohort at discharge (2.2 [4.0] vs. -0.2 [6.32], P = 0.003).

CONCLUSIONS

A temporal relationship with improvement in mental status was noted for most patients administered modafinil after aSAH. These findings, a favorable adverse-effect profile, and implications for goals-of-care decisions favor a low threshold for modafinil initiation in aSAH patients in the acute-care setting.

The neurosurgery research & education foundation-young neurosurgeons committee webinar series: Providing education and inspiration during the COVID-19 pandemic

OBJECTIVE

During the COVID-19 pandemic, the American Association of Neurological Surgeons (AANS) Young Neurosurgeons Committee (YNC) and Neurosurgery Research & Education Foundation (NREF) launched the YNC-NREF Webinar Series to provide young and aspiring neurosurgeons with timely information, education, and inspiration in the absence of in-person programming.

DESIGN

Five 90-minute Zoom webinars were evaluated, each including 1-2 keynote speakers, a panel discussion, and an audience question-and-answer section. Topics included overviews of neurosurgery, the match, subspecialties, and inspirational career stories. Optional pre- and post-webinar surveys with 11-point Likert-type scores were distributed to attendees. We compared groups using chi-squared and Kruskal-Willis tests, and perceptions pre- and post-webinar using Mann-Whitney tests.

SETTING

The webinars were live using Zoom, and the recordings were published on NREF's YouTube channel.

PARTICIPANTS

The webinar series targeted young neurosurgeons. The first five episodes had a particular focus on medical students and undergraduates.

RESULTS

A total of 673 unique participants attended the webinar series; 257 (38%) and 78 (11%) attendees completed the pre- and post-webinar survey, respectively. Respondents had high baseline interest in neurosurgery and were motivated to learn about the match and training in the US, understand neurosurgeons' day-to-day lives, and ask questions. There were significant differences in perceptions between USMSs, IMSs, and undergraduate students. The webinar improved attendees' knowledge about neurosurgical specialties, the match, and US neurosurgery training.

CONCLUSIONS

The YNC and NREF effectively engaged a large, diverse audience through an online webinar series, building a foundation for future virtual programming by organized neurosurgery. ACGME competencies.

Exploring the Validity and Reliability of Neurosurgery Residency Program Rankings: A Quantitative Analysis

OBJECTIVE

To evaluate the relationships between Doximity rankings (Doximity, Inc.) of residency programs and 2 new ranking systems based on publication rates and academic pursuits.

METHODS

We collected data on 550 neurosurgery graduates over 3 years. We analyzed the median number of published manuscripts per resident and the percentage of residents pursuing academic careers and compared them across the Doximity Research Productivity and Reputation Rankings. We used logistic regression to evaluate the relationships among the rankings, publication rates, and academic pursuits.

RESULTS

Neurosurgery residents published a median of 10 manuscripts per person (IQR: 6-17), and 50% (IQR: 33%-67%) of residents in a given program pursued an academic career. The distributions of the median number of published manuscripts across the Doximity Research Productivity Ranking and the Doximity Reputation Ranking tiers differed significantly (all P < 0.001). Similarly, the distribution of the percentage of residents pursuing an academic career across both published Doximity ranking systems' tiers differed significantly (all P = 0.02). Moreover, we found moderate agreement between the 2 Doximity rankings, fair agreement between the publication and the other 3 rankings, and slight agreement between the academic pursuit and the Doximity rankings.

CONCLUSIONS

We introduced 2 new methods to rank residency programs based on the number of graduates pursuing an academic position and the median number of published manuscripts per resident. By taking a comprehensive approach, neurosurgery applicants can ensure that they select a residency program that meets their needs and offers them the best opportunity for success.

Fenestrated Aneurysm Clip Trigeminal Decompression after CyberKnife Treatment Failure

Objective  This article describes a novel technique for trigeminal nerve decompression in the setting of refractory trigeminal neuralgia (TN). Design  Technical note with an illustrative case example and operative video. Setting  Outpatient, inpatient, and operating room of a quaternary neurosurgical referral center. Participant  A woman in her early 70s who had previously undergone linear accelerator-based stereotactic radiotherapy (i.e., CyberKnife) and achieved 2 years of partial pain relief. However, facial pain, numbness, and parasympathetic dysfunction returned and became unbearable. Main Outcome Measure  Durable relief of TN. Results  Microvascular decompression was recommended for refractory TN. Intraoperatively, the trigeminal nerve was markedly attenuated from previous irradiation, with the superior cerebellar artery (SCA) loop embedded in the nerve at its root entry zone. The arterial loop was mobilized into a new position superior to the nerve, thus liberating it from the impingement. The tentorium was incised, and a fenestrated aneurysm clip was positioned such that the SCA loop was transmitted via the fenestration. The clip was applied across the tentorium, thus suspending the artery in a kink-free orientation that made no contact with the nerve. Conclusion  This procedure provided excellent neurovascular decompression without placing mechanical strain on the nerve, relieving the patient's persistent postirradiation TN. The technique could have broader applications for other challenging or atypical microvascular decompression procedures.

Surgical management of spinal pathologies in the octogenarian: a narrative review

Optimal management paradigms of spinal pathologies in the octogenarian population are controversial given the higher incidence of comorbidities with concern for poor prognosis and fear of increased complications associated with surgical management. In this narrative review, we aim to detail the complex clinical considerations when approaching odontoid screw fixation/instrumented fusion, spinal decompression, and spinal fusion in the octogenarian. Literature review was conducted via Google Scholar and PubMed databases, with literature selected based on statistical power and clinical relevance to the following pathologies/surgical techniques: odontoid fracture, surgical decompression, and surgical fusion in the octogenarian. The aforementioned pathologies were selected based on prevalence in the advanced-age population in which surgical screening techniques and management remain nonuniform. Preoperative evaluation of the octogenarian patient increasingly includes frailty, sarcopenia, and osteopenia/osteoporosis assessments. In cases of odontoid fracture, conservative management appears to provide beneficial clinical outcomes with lower rates of complication compared to surgery; however, rates of radiographic odontoid fusion are far lower in conservatively managed patients. Regarding surgical decompression and fusion, the presence of comorbidities may be more predictive of outcome rather than age status, with the advent of minimally invasive techniques providing safety and efficacy in the surgical management of this age cohort. Age status may be less pertinent than previously thought in the decision to pursue spinal surgery for odontoid fracture, spinal decompression, or spinal fusion; however, each of these procedures has respective risks and benefits that must be considered within the context of each patient's comorbidity profile.

Predicting long-term outcomes after microvascular decompression for hemifacial spasm according to lateral spread response and immediate postoperative outcomes: a cohort study

OBJECTIVE

Microvascular decompression (MVD) is a well-established and highly effective treatment option for hemifacial spasm (HFS). Lateral spread response (LSR) has been used as an intraoperative indicator of HFS resolution, with controversial reliability. The purpose of this study was to determine long-term outcomes of MVD for HFS and the role of LSR and other preoperative predictors.

METHODS

The authors conducted a cohort study of all patients treated with MVD for HFS at a single institution from January 1, 1998, to December 31, 2019. In addition to a retrospective chart review, all patients were contacted at the time of the study to provide informed consent and responded to a telephone survey to ascertain their current disease and medication status. Patients with at least 12 months of postoperative follow-up were included. Statistical testing included a Student t-test, Fisher's exact test, logistic regression, and Cox proportional hazards analysis.

RESULTS

One hundred nineteen patients met study criteria; 41 (34%) had at least 10 years of clinical follow-up. HFS fully resolved in 93 (78%), symptoms subjectively improved in 11 (9%) and were unchanged in 15 (13%). Immediate postoperative HFS status did not correlate with long-term outcome (p = 0.13). Changes in LSR were not associated with outcome. Patients receiving neuromodulating agents had significantly longer preoperative duration of symptoms and were more likely to show persistent LSR intraoperatively. HFS recurrence was associated with younger age at the time of surgery but not with intraoperative LSR resolution.

CONCLUSIONS

This study demonstrated that MVD for HFS is highly effective for most patients. Neither intraoperative LSR change nor immediate postoperative status was predictive of long-term outcomes.

A Review of Preoperative Embolization Effectiveness in Patients With Arteriovenous Malformations

BACKGROUND AND OBJECTIVES

Preoperative embolization of arteriovenous malformations (AVMs) remains controversial. This study sought to analyze the cost-effectiveness of preoperative embolization of AVMs.

METHODS

Patients who underwent AVM resection at a single institute (January 1, 2015-December 31, 2020) were analyzed. Patients with preoperative embolization (embolization cohort) were compared with those without preoperative embolization (nonembolization cohort). Cost-effectiveness score (CE) was the primary outcome of interest and was determined by dividing the total 1-year cost by effectiveness, which was derived from a validated preoperative to last follow-up change in the modified Rankin Scale utility score. A lower CE signifies a more cost-effective treatment strategy.

RESULTS

Of 188 patients, 88 (47%) underwent preoperative embolization. The mean (SD) total cost was higher in the embolization group than in the nonembolization group ($117 594 [$102 295] vs $84 348 [$82 326]; P < .001). The mean (SD) CE was higher in the embolization cohort ($336 476 [$1 303 842]) than in the nonembolization cohort ($100 237 [$246 255]; P < .001). Among patients with Spetzler-Martin (SM) grade I and II AVMs, the mean (SD) CE was higher in the embolization (n = 40) than in the nonembolization (n = 72) cohort ($164 950 [$348 286] vs $69 021 [$114 938]; P = .004). Among patients with SM grade III AVMs, the mean (SD) CE was lower in the embolization (n = 33) than in the nonembolization (n = 25) cohort ($151 577 [$219 130] vs $189 195 [$446 335]; P = .006). The mean (SD) CE was not significantly different between cohorts among patients with higher-grade AVMs (embolization cohort [n = 3] vs nonembolization cohort [n = 15]: $503 639 [$776 492] vs $2 048 419 [$4 794 758]; P = .49). The mean CE for embolized SM grade III aneurysms was nonsignificant in the ruptured group; however, for the unruptured group, CE was significantly higher in the embolization cohort (n = 26; $160 871 [$240 535]) relative to the nonembolization cohort (n = 15; $108 152 [$166 446]) ( P = .006).

CONCLUSION

Preoperative embolization was cost-effective for patients with SM grade III AVMs but not for patients with lower-grade AVMs.

Early Treatment of Ruptured Cerebral Arteriovenous Malformations: Analysis of Neurological Outcomes and Health Care Costs

BACKGROUND

The timing of surgical resection is controversial when managing ruptured arteriovenous malformations (AVMs) and varies considerably among centers.

OBJECTIVE

To retrospectively analyze clinical outcomes and hospital costs associated with delayed treatment in a ruptured cerebral AVM patient cohort.

METHODS

Patients undergoing surgical treatment for a ruptured cerebral AVM (January 1, 2015-December 31, 2020) were retrospectively analyzed. Patients who underwent emergent treatment of a ruptured AVM because of acute herniation were excluded, as were those treated >180 days after rupture. Patients were stratified by the timing of surgical intervention relative to AVM rupture into early (postbleed days 1-20) and delayed (postbleed days 21-180) treatment cohorts.

RESULTS

Eighty-seven patients were identified. The early treatment cohort comprised 75 (86%) patients. The mean (SD) length of time between AVM rupture and surgical resection was 5 (5) days in the early cohort and 73 (60) days in the delayed cohort ( P < .001). The cohorts did not differ with respect to patient demographics, AVM size, Spetzler-Martin grade, frequency of preoperative embolization, or severity of clinical presentation ( P ≥ .15). Follow-up neurological status was equivalent between the cohorts ( P = .65). The associated mean health care costs were higher in the delayed treatment cohort ($241 597 [$99 363]) than in the early treatment cohort ($133 989 [$110 947]) ( P = .02). After adjustment for length of stay, each day of delayed treatment increased cost by a mean of $2465 (95% CI = $967-$3964, P = .002).

CONCLUSION

Early treatment of ruptured AVMs was associated with significantly lower health care costs than delayed treatment, but surgical and neurological outcomes were equivalent.

Management of basilar fenestration aneurysms: a systematic review with an illustrative case report

BACKGROUND

Basilar artery (BA) fenestration aneurysm (BAFA) is a rare phenomenon commonly accompanying other aneurysms. Treatment is challenging, and few cases have been reported. This review investigated the management outcomes of BAFAs.

METHODS

Publication databases were searched to identify studies evaluating outcomes of endovascular treatment (EVT) and microsurgical treatment of BAFAs from inception through 2021. Outcomes (clinical, angiographic, postoperative complications, and retreatment rates) were collected and analyzed. The authors present their case of a patient treated for a BAFA.

RESULTS

Including the authors' case, 184 patients with 209 BAFAs were reported in 68 studies. Most patients (130/175; 74.3%) presented with ruptured aneurysms, most commonly involving the proximal segment of the BA. Most BAFAs were small (52/103, 50.5%) and saccular (119/143, 83.2%). Most patients underwent EVT (143/184, 77.7%); the rest underwent microsurgery. Postoperative complications after EVT occurred in 10 (8.3%) of 120 patients, with 4 of the 10 experiencing strokes. At clinical follow-up, most EVT patients (74/86, 86.0%) showed good outcomes; 3.9% (2/51) had died. Most aneurysms managed with EVT (56/73, 76.7%) showed complete occlusion at follow-up; 7.3% (8/109) were retreated. Postoperative complications occurred in 62.2% (23/37) of microsurgical patients; 5 (21.7%) of the 23 experienced strokes. All patients showed good clinical outcomes at follow-up. Most aneurysms (22/28, 78.6%) treated microsurgically showed complete occlusion at angiographic follow-up, with no retreatment required.

CONCLUSION

BAFAs are often symptomatic; thus, treatment is challenging. By the 2000s, treatment had moved from microsurgical to endovascular modalities, with good clinical and angiographic outcomes.

An institutional experience in applying quality improvement measures to pituitary surgery: clinical and resource implications

OBJECTIVE

The aim of this study was to report the authors' experience developing a Lean Six Sigma clinical care pathway (CCP) for endoscopic endonasal transsphenoidal operations.

METHODS

Using Lean Six Sigma quality improvement principles-including the define, measure, analyze, improve, and control framework-the authors developed a CCP for endoscopic endonasal transsphenoidal operations, incorporating preoperative, intraoperative, and inpatient and outpatient postoperative phases of care. Efficacy and quality metrics were defined as postoperative length of stay (LOS), presentation to the emergency department (ED) or readmission within 30 days of discharge, and hospital charges. The study included all adult patients who underwent elective endoscopic endonasal resection for pituitary adenoma, Rathke's cleft cyst, craniopharyngioma, pituicytoma, or arachnoid cyst during the sampling period (April 1, 2018, to December 31, 2022).

RESULTS

Two hundred twenty-eight patients met criteria and were included; 94 were treated before and 134 were treated after implementation of the CCP. Differences between groups in age, gender, race, BMI, American Society of Anesthesiologists classification, geographic distribution, preoperative serum sodium, tumor size, adenoma functional status, and prior surgery were not significant. The mean postoperative LOS significantly decreased from 4.5 to 1.7 days following CCP implementation (p < 0.0001); LOS variability also decreased, with the standard deviation declining from 3.1 to 1.5 days. The proportion of patients discharged on postoperative day (POD) 1 significantly increased from 0% to 61.9% (p < 0.0001). Fewer than one-quarter of the patients (23.4%) were discharged by POD 2 prior to the CCP, while 88.8% of were discharged by POD 2 after CCP implementation (p < 0.0001). Rates of 30-day ED presentations or readmissions were not significantly different (2.1% vs 6.0%, p = 0.20, and 7.5% vs 6.7%, p > 0.99, respectively). Mean per-patient hospital costs declined from $38,326 to $26,289 (p < 0.0001), with an associated change in cost variability from a standard deviation of $16,716 to $12,498.

CONCLUSIONS

CCP implementation significantly improved LOS and costs of endoscopic endonasal resection, without adversely impacting postoperative ED presentations or readmissions.

Calcifying Pseudoneoplasm of the Neuraxis: An Institutional Series of Ten Cases and Review of the Literature to Date

BACKGROUND

Calcified pseudoneoplasms of the neuraxis (CAPNONs) are rare, fibro-osseous lesions with an unknown cause that may present anywhere along the neuroaxis. Little is known about how intracranial CAPNONs present and about patients' long-term outcomes.

METHODS

A retrospective institutional review of intracranial pathology-confirmed CAPNONs was performed. Presenting clinical features, management, and clinical outcomes are highlighted. A literature review of intracranial CAPNON lesions was also performed to build on our series.

RESULTS

Ten patients were identified who met the inclusion criteria. Most patients presented with headaches (n = 6; 60%), seizures (n = 5; 50.0%), and neck and facial pain (n = 3; 30.0%). Most lesions were supratentorial (n = 7; 70.0%), with 3 infratentorial origins. Surgical resection was the most common initial management undertaken (n = 7; 70.0%). No new permanent postoperative neurologic deficits were identified. The median clinical and/or radiographic follow-up for all patients was 6.8 years (range, 0.7-23.3 years), with no recurrence of disease for 5 patients who underwent gross total resection. Four of 5 patients with residual or nonresectable lesions showed no interval growth on radiographic follow-up; 1 patient showed progression and worsening of presenting symptoms 2 months after resection. Resection substantially improved seizures and headaches in patients presenting with these symptoms (80% and 83.3%, respectively).

CONCLUSIONS

Intracranial CAPNONs may present with a wide variety of symptoms characteristic of the site of origin. The outcomes of these symptoms regarding survival and disease control are generally favorable, although resection does not always yield complete resolution of presenting deficits in certain patients, particularly those presenting with headaches or neck/facial pain.

Sphenoparietal Sinus Transposition: Operative Technique for Optimizing Pretemporal Posterior Circulation Access While Preserving the Sylvian Venous Complex

BACKGROUND

Transsylvian approaches are a cornerstone of complex cranial operations, with wide applicability across cerebrovascular, skull base, and neuro-oncology operations. Deep lesions, especially those involving the basilar apex, midbrain, or interpeduncular fossa, require wide exposures that may be inhibited by the presence of a large complex of superficial sylvian veins (SSV) draining into the sphenoparietal sinus. This report describes technical and clinical aspects of the sphenoparietal sinus transposition (SPST) technique.

METHODS

Technical case report of the SPST technique, including a step-by-step neuroanatomic description, overview of common indications, clinical pearls and pitfalls, and illustrative case examples.

RESULTS

Once the benefits of proceeding with SPST have been established, the maneuver is initiated with 2 stepwise dural incisions: an incision from lateral to medial along the lateral margin of the lesser sphenoid wing, followed by an orthogonal cut across the temporal pole down the middle fossa floor. The pretemporal dura is peeled off the lateral wall of the cavernous sinus, allowing mobilization of the SSV complex and temporal pole posteriorly without disrupting or straining the connection point at the sphenoparietal sinus. Illustrative case examples include a clip reconstruction of a basilar apex aneurysm for which earlier endovascular treatment had failed and microsurgical resection of a peduncular cavernous malformation.

CONCLUSIONS

SPST is a simple but versatile technique with important applications in complex cranial surgery. By mobilizing the SSV complex together with its dural attachment, the transsylvian corridor can be markedly widened, allowing access to the basilar apex region and ventral midbrain.

Occipital Artery to Middle Cerebral Artery Direct Bypass: A Salvage Revascularization Technique for Ischemic Moyamoya Disease

OBJECTIVE

The main treatment for moyamoya disease (MMD) is revascularization surgery. Most bypasses use the superficial temporal artery (STA) as the donor vessel. However, even if the STA-middle cerebral artery (MCA) bypass is functioning, the affected hemisphere can continue to be symptomatically malperfused. We sought to assess the efficacy of salvage direct revascularization surgery using the occipital artery (OA) as a donor vessel in patients with ischemic MMD who experience continued cerebral malperfusion despite previous successful STA-MCA bypass.

METHODS

We retrospectively analyzed the cerebrovascular databases of 2 surgeons and described patients in whom the OA was used as the donor vessel for direct revascularization.

RESULTS

Seven patients were included (5 women). Previous STA-MCA bypasses were direct (n = 2), indirect (n = 3), or combined/multiple (n = 2). The mean (SD) interval between STA-MCA and OA-MCA procedures was 29.2 (13.1) months. Despite an intact STA-MCA bypass in all 7 cases, all 7 patients had recurrent symptoms and demonstrated residual impaired cerebral perfusion. All 7 patients underwent successful OA-MCA direct revascularization. Follow-up perfusion imaging was obtained for 6 of 7 patients. All 6 of these patients demonstrated improved cerebral blood flow to the revascularized hemispheres. All 7 patients demonstrated clinical improvement.

CONCLUSIONS

Patients with ischemic MMD who have continued symptoms and cerebral malperfusion despite previous successful STA-MCA bypass present a challenging clinical scenario. Our series highlights the potential utility of the OA-MCA direct bypass as a salvage therapy for these patients.

Radiation-Induced Cerebral Cavernous Malformations: A Single-Center Experience and Systematic Literature Review

OBJECTIVE

Radiation was first demonstrated to be associated with cavernomagenesis in 1992. Since then, a growing body of literature has shown the unique course and presentation of radiation-induced cavernous malformations (RICMs). This study summarizes the literature on RICMs and presents a single-center experience.

METHODS

A prospectively maintained single institution vascular malformation database was searched for all cases of intracranial cavernous malformation (January 1, 1997-December 31, 2021). For patients with a diagnosis of RICM, information on demographic characteristics, surgical treatments, radiation, and surgical outcomes was obtained and analyzed. A comprehensive literature search was conducted using PubMed, Embase, Cochrane, and Web of Science databases for all reported cases of RICM.

RESULTS

A retrospective review of 1662 patients treated at a single institution yielded 10 patients with prior radiation treatment in the neck or head region and a subsequent diagnosis of intracranial RICM. The median (interquartile range) latency between radiation and presentation was 144 (108-192) months. Nine of 10 patients underwent surgery; symptoms improved for 5 patients, worsened for 3, and were stable for 1. The systematic literature review yielded 64 publications describing 248 patients with RICMs. Of the 248 literature review cases, 71 (28.6%) involved surgical resection. Of 39 patients with reported surgical outcomes, 32 (82%) experienced improvement.

CONCLUSIONS

RICMs have a unique course and epidemiology. RICMs should be considered when patients with a history of radiation present with neurologic impairment. When RICMs are identified, symptomatic patients can be treated effectively with surgical excision and close follow-up.

The LazyBox Educational Intervention Trial: Can Longitudinal Practice on a Low-Fidelity Microsurgery Simulator Improve Microsurgical Skills?

Introduction Every surgical trainee must acquire microsurgical skills within a limited timeframe. Therefore, identifying effective educational strategies to help learners attain these skills is crucial. Objective Establish the effectiveness of a low-fidelity microsurgery simulator to improve the execution and one's perception of the difficulty of basic surgical techniques. Methods From 2021 to 2022, 24 medical students were randomized to either (1) a treatment group (n=12) that engaged in longitudinal practice on a low-fidelity microsurgery simulator (the LazyBox) or (2) a control group (n=12) that did not practice. Students performed vessel loop ligation, catheter macroanastomosis, and synthetic vessel microanastomosis prior to and six weeks after intervention. Both objective metrics and subjective metrics (Swedish Occupational Fatigue Inventory (SOFI) and Surgery Task Load Index (SURG-TLX)) were obtained. Results The treatment and control arms had 1.2 (SD = 2.6) and 2.1 (SD = 2.4) points increase in the vessel loop ligation, respectively (p = 0.39). The treatment and control arms had a 3.4 (SD = 4.1) and 2.9 (SD = 3.6) points increase in the macroanastomosis task, respectively (p = 0.74). In the synthetic vessel microanastomosis task training, the experimental and control arms showed a 5.4 (SD = 8.3) and a 2.9 (SD = 5.6) points increase, respectively (p = 0.30). No differences were found between the groups regarding survey metrics of mental (p = 0.82), temporal (p = 0.23), and physical demands (p = 0.48). Conclusion In our randomized educational intervention, we found no significant difference in objective and subjective metrics of microsurgical task performance between learners who did and did not use the LazyBox simulator.

Decision-Making in Clival Mass Lesions: Risk Factors for Malignant Disease and an Illustrative Case Example

Introduction  Clival tumors are rare and heterogeneous. Although some benign prototypical sellar lesions may present as clival tumors, the likelihood of malignant disease is higher. Here we define a novel algorithm for the workup and management of clival masses through an illustrative case of colorectal adenocarcinoma metastasis to the clivus. Methods  In this case report, the best practice guidelines for managing clival masses are described through a literature review and refined by senior author consensus. We conducted a focused systematic review to characterize the present case in the context of clival metastasis from gastrointestinal malignancy. Results  An 83-year-old woman presented with 4 weeks of headaches and blurry vision. Examination revealed partial right abducens and left oculomotor palsies. Magnetic resonance imaging (MRI) identified a large, weakly enhancing sellar and clival mass with sphenoid sinus extension. An aggressive subtotal endoscopic endonasal resection was performed with removal of all sphenoid, clival, and sellar disease without cavernous sinus wall resection. Pathology confirmed colorectal adenocarcinoma; computed tomography (CT) imaging identified an ascending colon mass with metastases to the liver and mesenteric nodes. Palliative oncologic therapies were recommended, but she elected hospice, and died 3 months after initial presentation. Gastrointestinal clival metastases are exceedingly rare among sellar and clival pathologies, with eight prior cases reported, most of which presented with diplopia from abducens nerve involvement. Conclusion  Clival masses are uncommon skull base lesions that are associated with more aggressive diseases. We present a consolidated framework for decision-making in these challenging patients, alongside an unusual case example that illustrates the importance of increased suspicion for malignant clinical entities in this setting.

The Neurosurgery Match: COVID-19 Comparison and Bibliometric Analysis

BACKGROUND

Because of the effect of COVID-19 on academic opportunities, as well as limitations on travel, away rotations and in-person interviews, COVID-19-related changes could impact the neurosurgical resident demographics. Our aim was to retrospectively review the demographics of the previous 4 years of neurosurgery residents, provide bibliometric analysis of successful applicants, and analyze for the effects of COVID-19 on the match cycle.

METHODS

All American Association of Neurological Surgeons' residency program websites were examined for a list of demographic characteristics for current postgraduate years 1 to 4. Gathered information included gender, undergraduate and medical institution and state, medical degree status, and prior graduate programs.

RESULTS

A total of 114 institutions and 946 residents were included in the final review. Most (676, or 71.5%) of the residents included in the analysis were male. Of the 783 who studied within the United States, 221 (28.2%) residents stayed within the same state of his or her medical school. Fewer residents (104 of 555, or 18.7%) stayed within the same state of his or her undergraduate school. Demographic information and geographic switching relative to medical school, undergraduate school, and hometown showed no significant changes between pre-COVID-19 and COVID-19-matched cohorts overall. The median number of publications per resident significantly increased for the COVID-19-matched cohort (median, 1; interquartile range [IQR], 0-4.75) when compared with the non-COVID-19-matched cohort (median, 1; IQR, 0-3, P = 0.004), as did first author publications (median, 1; IQR, 0-1 vs. median, 1; IQR, 0-1; P = 0.015), respectively. The number of residents matching into the same region in the Northeast relative to undergraduate degree was significantly greater after COVID-19 (56 [58%] versus 36 [42%], P = 0.026). The West demonstrated a significant increase in the mean number of total publications (4.0 ± 8.5 vs. 2.3 ± 4.2, P = 0.02) and first author publications (1.24 ± 2.33 vs. 0.68 ± 1.47, P = 0.02) after COVID-19, with the increase in first author publications being significant in a test of medians.

CONCLUSIONS

Herein we characterized the most recently matched neurosurgery applicants, paying particular attention to changes over time in relation to the onset of the pandemic. Apart from publication volume, characteristics of residents and geographical preferences did not change with the influence of COVID-19-induced changes in the application process.

Spinal Dorsal Intradural Arteriovenous Fistulas: Natural History, Imaging, and Management

In this review, we describe the pathophysiology, diagnosis, and treatment of spinal dorsal intradural arteriovenous fistulas (DI-AVFs), focusing on novel research areas. DI-AVFs compose the most common subgroup of spinal arteriovenous lesions and most commonly involve the thoracic spine, followed by lumbar and sacral segments. The pathogenesis underlying DI-AVFs is an area of emerging understanding, thought to be attributable to venous congestion and hypertension that precipitate ascending myelopathy. Patients with DI-AVFs typically present with motor, sensory, or urinary dysfunction, although a wide swath of other less common symptoms has been reported. DI-AVFs can be subdivided by spinal region, which in turn is associated with 4 distinct clinical phenotypes: craniocervical junction (CCJ), subaxial cervical, thoracic, and lumbosacral. Patients with CCJ and lumbosacral DI-AVFs have particularly interesting presentations and treatment considerations. High-value diagnostic findings on MRI include flow voids, missing-piece sign, and T2-weighted intramedullary hyperintensity. However, digital subtraction angiography is the gold standard for diagnosis and localization of DI-AVFs and for definitive treatment planning. Surgical disconnection of DI-AVFs is almost universally curative and frontline treatment, especially for CCJ and lumbosacral DI-AVFs. Endovascular techniques evolve in promising ways, such as improved visualization, distal access, and liquid embolic techniques. The pathophysiology of DI-AVFs is better understood using newly identified radiologic diagnostic markers. Despite new techniques and devices introduced in the endovascular field, surgery remains the gold-standard treatment for DI-AVFs.

That which is unseen: 3D printing for pediatric cerebrovascular education

INTRODUCTION

Pediatric cerebrovascular lesions are very rare and include aneurysms, arteriovenous malformations (AVM), and vein of Galen malformations (VOGM).

OBJECTIVE

To describe and disseminate a validated, reproducible set of 3D models for optimization of neurosurgical training with respect to pediatric cerebrovascular diseases METHODS: All pediatric cerebrovascular lesions treated at our institution with adequate imaging studies during the study period 2015-2020 were reviewed by the study team. Three major diagnostic groups were identified: aneurysm, AVM, and VOGM. For each group, a case deemed highly illustrative of the core diagnostic and therapeutic principles was selected by the lead and senior investigators for printing (CSG/JM). Files for model reproduction and free distribution were prepared for inclusion as Supplemental Materials.

RESULTS

Representative cases included a 7-month-old female with a giant left MCA aneurysm; a 3-day-old male with a large, complex, high-flow, choroidal-type VOGM, supplied from bilateral thalamic, choroidal, and pericallosal perforators, with drainage into a large prosencephalic vein; and a 7-year-old male with a left frontal AVM with one feeding arterial vessel from the anterior cerebral artery and one single draining vein into the superior sagittal sinus CONCLUSION: Pediatric cerebrovascular lesions are representative of rare but important neurosurgical diseases that require creative approaches for training optimization. As these lesions are quite rare, 3D-printed models and open source educational materials may provide a meaningful avenue for impactful clinical teaching with respect to a wide swath of uncommon or unusual neurosurgical diseases.

Competitive neurosurgery residency programs: Predictors of matching outcome and research productivity

OBJECTIVE

The aim of this study was to provide a comprehensive assessment of preresidency research and school as predictors of competitive neurosurgery matching and to assess for any correlations between preresidency and intraresidency research productivity.

METHODS

Individuals who graduated from US neurosurgery programs from 2018 through 2020 were assessed for medical school, degree (MD, DO, or PhD), preresidency versus intraresidency publications, author order, article type, and neurosurgery matching outcomes.

RESULTS

Medical school ranking (top 50) and the number of published papers (≥3) before intern year were predictors for matching to a top-25 residency program after adjusting for other covariates (p < 0.001, p = 0.002, respectively). On average, individuals who published more papers before residency published more papers during residency. For the comprehensive clinical papers category, there was a significant difference between individuals from the top 25 residency programs and others, with a stronger correlation between the number of preresidency publications and intraresidency publications for neurosurgeons who attended a top-25 residency program (r = 0.378 and r = 0.179, respectively; p = 0.02).

CONCLUSION

Medical school ranking and research productivity as measured by the number of published papers were independently associated with matching to the top 25 residency programs. In addition, high research productivity in the preresidency years was associated with continued productivity during residency, especially in the category of comprehensive clinical papers.

Double-Interposition Bypass: Technical Case Report of a Novel Intraoperative Bypass Salvage Technique

BACKGROUND AND IMPORTANCE

Complex cerebrovascular bypass operations may confer an increased risk of intraoperative complications, such as graft thrombosis. Novel techniques are needed to optimize the management of these challenging cases.

CLINICAL PRESENTATION

A woman in her late 20s was incidentally diagnosed with a 1.5-cm basilar apex aneurysm, which grew to 3.5 cm over 2 years of active surveillance. Definitive treatment was then recommended with flow reversal and Hunterian ligation of the basilar trunk planned as a radial artery graft (RAG) bypass: M2 (S-Ec) RAG (E-Sc*) P2. Intraoperative graft thrombosis prompted multiple attempted salvage maneuvers; however, complete excision and repeat anastomosis were ultimately required. The procedure was completed using a novel double-interposition technique, with ligation of the index RAG approximately 1 cm proximal to the distal anastomosis (final bypass: M2 [S-Ec*] RAG [E-Ec*] RAG' [E-Sc] P2). These technical modifications yielded a less deep recipient site for the repeat bypass and an end-to-end anastomosis rather than an end-to-side anastomosis, collectively facilitating a more efficient and facile salvage. The patient recovered well from surgery, and flow reversal was successfully achieved within the aneurysm.

CONCLUSION

Despite the increased risk of intraoperative thrombosis with complex cerebrovascular bypass operations, facility with salvage techniques can lead to technically and clinically excellent outcomes. We report the successful use of a novel fourth-generation double-interposition bypass that shortens the working distance and uses a more favorable anastomosis technique. This bypass may facilitate safe and efficient microsurgery in patients who require complete revision of an intracranial-intracranial construct.

Ruptured vertebrobasilar junction aneurysm supplied by reversed flow from the anterior spinal artery: Illustrative case report

BACKGROUND AND IMPORTANCE

In patients with vertebral artery (VA) occlusion, spontaneous flow reversal may occur in the anterior spinal artery (ASA) as a source of compensatory supply to the posterior circulation. Turbulent flow and increased flux through these small arteries may predispose to luminal damage and intracranial aneurysm formation. We report a novel case of a ruptured ASA-VA junction aneurysm in a patient with chronic bilateral VA occlusion, successfully treated with endovascular embolization.

CLINICAL PRESENTATION

A 62-year-old female with uncontrolled hypertension presented with acute-onset headache, emesis, neck stiffness, and decreased level of consciousness. Head computed tomography demonstrated diffuse cisternal subarachnoid hemorrhage with intraventricular extension and ventriculomegaly. Computed tomography angiography showed left VA atresia and chronic right VA occlusion just distal to the posterior inferior cerebellar artery origin, as well as a complex, bilobed aneurysm at the ASA-VA junction. Angiography demonstrated flow reversal from the ASA into the distal stump of the occluded right VA, which in turn filled the aneurysm. Of note, the patient's posterior circulation was predominantly supplied by the dilated ASA, and associated collaterals from ASA and right VA stump. The aneurysm was accessed and embolized using superselective microcatheterization over a soft microguidewire through the right cervical VA perforators supplying retrograde flow into and through the ASA.

CONCLUSION

ASA-VA aneurysms are exceedingly rare, and generally associated with atypical flow dynamics. Dynamic treatment strategies may be needed, especially in the setting of subarachnoid hemorrhage.

Cost-Effectiveness of Forgoing Postoperative Catheter Angiography After Microsurgical Occlusion of Spinal Dorsal Intradural Arteriovenous Fistulas

OBJECTIVE

Spinal dorsal intradural arteriovenous fistulas (DI-AVFs) represent 70% of all spinal vascular lesions. Diagnostic tools include pre- and postoperative digital subtraction angiography (DSA) and intraoperative indocyanine green videoangiography (ICG-VA). ICG-VA has a high predictive value in DI-AVF occlusion, but postoperative DSA remains a core component of postoperative protocols. The aim of this study was to evaluate the potential cost reduction of forgoing postoperative DSA after microsurgical occlusion of DI-AVFs.

METHODS

Cohort-based cost effectiveness study of all DI-AVFs within a prospective, single-center cerebrovascular registry from January 1, 2017, to December 31, 2021.

RESULTS

Complete data including intraoperative ICG-VA and costs were available for 11 patients. Mean (SD) age was 61.5 (14.8) years. All DI-AVFs were treated with microsurgical clip ligation of the draining vein. ICG-VA showed complete obliteration in all patients. Postoperative DSA was performed for 6 patients and confirmed complete obliteration. Mean (SD) cost contributions for DSA and ICG-VA were $11,418 ($4,861) and $12 ($2), respectively. Mean (SD) total costs were $63,543 ($15,742) and $53,369 ($27,609) for patients who did and did not undergo postoperative DSA, respectively. Comorbidity status was identified as the main driver of total cost (P = 0.01 after adjusting for postoperative DSA status).

CONCLUSIONS

ICG-VA is a powerful diagnostic tool in demonstrating microsurgical cure of DI-AVFs, with a negative predictive value of 100%. Eliminating postoperative DSA in patients with confirmed DI-AVF obliteration on ICG-VA may yield substantial cost savings, in addition to sparing patients the risk and inconvenience of a potentially unnecessary invasive procedure.

Outcomes in Patients with Aneurysmal Subarachnoid Hemorrhage Receiving Sulfonylureas: A Propensity-Adjusted Analysis

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with increased blood-brain barrier permeability, disrupted tight junctions, and increased cerebral edema. Sulfonylureas are associated with reduced tight-junction disturbance and edema and improved functional outcome in aSAH animal models, but human data are scant. We analyzed neurological outcomes in aSAH patients prescribed sulfonylureas for diabetes mellitus.

METHODS

Patients treated for aSAH at a single institution (August 1, 2007-July 31, 2019) were retrospectively reviewed. Patients with diabetes were grouped by presence or absence of sulfonylurea therapy at hospital admission. The primary outcome was favorable neurologic status at last follow-up (modified Rankin Scale score ≤2). Variables with an unadjusted P-value of <0.20 were included in a propensity-adjusted multivariable logistic regression analysis to identify predictors of favorable outcomes.

RESULTS

Of 1013 aSAH patients analyzed, 129 (13%) had diabetes at admission, and 16 of these (12%) were receiving sulfonylureas. Fewer diabetic than nondiabetic patients had favorable outcomes (40% [52/129] vs. 51% [453/884], P = 0.03). Among diabetic patients, sulfonylurea use (OR 3.90, 95% CI 1.05-15.9, P = 0.046), Charlson Comorbidity Index <4 (OR 3.66, 95% CI 1.24-12.1, P = 0.02), and absence of delayed cerebral infarction (OR 4.09, 95% CI 1.20-15.5, P = 0.03) were associated with favorable outcomes in the multivariable analysis.

CONCLUSIONS

Diabetes was strongly associated with unfavorable neurologic outcomes. An unfavorable outcome in this cohort was mitigated by sulfonylureas, supporting some preclinical evidence of a possible neuroprotective role for these medications in aSAH. These results warrant further study on dose, timing, and duration of administration in humans.

Association between external ventricular drain removal or replacement and prophylactic anticoagulation in patients with aneurysmal subarachnoid hemorrhage: a propensity-adjusted analysis

BACKGROUND

Withholding prophylactic anticoagulation from patients with aneurysmal subarachnoid hemorrhage (aSAH) before external ventricular drain (EVD) removal or replacement remains controversial. This study analyzed whether prophylactic anticoagulation was associated with hemorrhagic complications related to EVD removal.

METHOD

All aSAH patients treated from January 1, 2014, to July 31, 2019, with an EVD placed were retrospectively analyzed. Patients were compared based on the number of prophylactic anticoagulant doses withheld for EVD removal (> 1 vs. ≤ 1). The primary outcome analyzed was deep venous thrombosis (DVT) or pulmonary embolism (PE) after EVD removal. A propensity-adjusted logistic-regression analysis was performed for confounding variables.

RESULTS

A total of 271 patients were analyzed. For EVD removal, > 1 dose was withheld from 116 (42.8%) patients. Six (2.2%) patients had a hemorrhage associated with EVD removal, and 17 (6.3%) patients had a DVT or PE. No significant difference in EVD-related hemorrhage after EVD removal was found between patients with  > 1 versus ≤ 1 dose of anticoagulant withheld (4 of 116 [3.5%] vs. 2 of 155 [1.3%]; p = 0.41) or between those with no doses withheld compared to ≥ 1 dose withheld (1 of 100 [1.0%] vs. 5 of 171 [2.9%]; p = 0.32). After adjustment, withholding > 1 dose of anticoagulant versus ≤ 1 dose was associated with the occurrence of DVT or PE (OR 4.8; 95% CI, 1.5-15.7; p = 0.009).

CONCLUSIONS

In aSAH patients with EVDs, withholding > 1 dose of prophylactic anticoagulant for EVD removal was associated with an increased risk of DVT or PE and no reduction in catheter removal-associated hemorrhage.

Approach Selection Strategies for Repeat Resection of Brain Cavernous Malformations: Cohort Study

BACKGROUND

Neurosurgical management of cerebral cavernous malformations (CMs) often benefits from using skull base approaches. Although many CMs are cured by resection, residual or recurrent disease may require repeat resection.

OBJECTIVE

To review approach selection strategies for reoperation of CMs to aid decision-making for repeat procedures.

METHODS

In this retrospective cohort study, a prospectively maintained single-surgeon registry was queried for patients with CMs who underwent repeat resection from January 1, 1997, to April 30, 2021.

RESULTS

Of 854 consecutive patients, 68 (8%) underwent 2 operations; 40 had accessible data on both. In most reoperations (33/40 [83%]), the index approach was repeated. In most reoperations using the index approach (29/33 [88%]), that approach was deemed ideal (no equivalent or superior alternative), whereas in some (4/33 [12%]), the alternative approach was deemed unsafe because of conformation of the tract. Among patients with reoperations using an alternative approach (7/40 [18%]), 2 with index transsylvian approaches underwent bifrontal transcallosal approaches, 2 with index presigmoid approaches underwent extended retrosigmoid revisions, and 3 with index supracerebellar-infratentorial approaches underwent alternative supracerebellar-infratentorial trajectory revisions. Among patients with reoperations with an alternative approach considered or selected (11/40 [28%]), 8 of 11 patients had a different surgeon for the index resection than for the repeat resection. The extended retrosigmoid-based approaches were used most often for reoperations.

CONCLUSION

Repeat resection of recurrent or residual CMs is a challenging neurosurgical niche at the intersection of cerebrovascular and skull base disciplines. Suboptimal index approaches may limit surgical options for repeat resection.

Thrombotic, dolichoectatic, distal PCA aneurysm treated with excision and P2-P2 reanastomosis

Posterior cerebral artery (PCA) aneurysms are rare and often optimally treated with clip reconstruction.^1-3 Complex cases may require aneurysm excision with in situ reanatomosis.^4-6 A woman in her early 40s presented with 2 weeks of severe headache and received a diagnosis of a thrombotic, dolichoectatic, distal right P2 aneurysm. Clip reconstruction was recommended. After providing consent, the patient underwent a right subtemporal approach. The P2 aneurysm was encountered in the ambient cistern. The aneurysm and its inflow and outflow arteries were isolated, and bleeding was controlled with temporary clips. Primary clip reconstruction was aborted due to a neck configuration that precluded preservation of the outflow vessels during primary clip reconstruction. The decision was made to excise the aneurysm and perform a P2-P2 end-to-end reanastomosis.⁷ After completion of the initial bypass, indocyanine green (ICG) videoangiography indicated bypass thrombosis, which was thought to be attributable to poor tissue quality from inadequate vessel trimming at the anastomosis site. We elected to excise the bypass, trim both P2 ends back to healthy tissue, and perform a repeat end-to-end P2-P2 reanastomosis, which ultimately resulted in successful revascularization with ICG confirmation. Postoperative angiography confirmed complete obliteration of the aneurysm with stable graft patency, and the patient remained intact at her neurologic baseline through last follow-up at 6 weeks after discharge from the hospital. This video demonstrates microsurgical nuances for deep end-to-end reanastomosis as well as intraoperative troubleshooting in the setting of a complex ruptured posterior circulation aneurysm. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Experience and Balance: Long-Term Trends in Preferred Skull Base Approach for a Case Series of Cavernous Malformation Resections

BACKGROUND

Skull base approaches are a foundation of modern cerebrovascular surgery; however, their application over time has varied.

OBJECTIVE

To assess trends in skull base approach selection for cavernous malformation (CM) resection.

METHODS

This is a retrospective case series of all first-time CM resections by a single surgeon from 1997 to 2021. Cases were classified by craniotomy and approach. Four sets of common comparator skull base approaches were identified by coauthor consensus: pterional and orbitozygomatic; retrosigmoid, extended retrosigmoid (xRS), and far-lateral; suboccipital and torcular; and trans-cerebellar peduncle (MCP) and transcerebellopontine angle. Counts were binned by 5-year or 10-year clusters for descriptive statistical assessment of temporal trends.

RESULTS

In total, 372 primary CM resections met the study criteria and were included. Orbitozygomatic approach use increased during the second 5-year period, after which the pterional approach rapidly became and remained the preferred approach. During the first two 5-year periods, the far-lateral approach was preferred to the retrosigmoid and xRS approaches, but the xRS approach grew in popularity and accounted for >50% of operations in this comparator group. Trans-MCP use compared with the transcerebellopontine angle approach closely mirrored the change in xRS use. The midline suboccipital approach accounted for a larger proportion (range, 62%-88%) of cases than the torcular approach (range, 12%-38%) across all periods.

CONCLUSION

The xRS and trans-MCP approaches have been increasingly used over time, while the orbitozygomatic and far-lateral approaches have become less common. These trends seem to reflect versatility, efficiency, and safety of these techniques.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Far Lateral Approach

Introduction  Skull base neuroanatomy is classically taught using surgical atlases. Although these texts are critical and rich resources for learning three-dimensional (3D) relationships between key structures, we believe they could be optimized and complemented with step-by-step anatomical dissections to fully meet the learning needs of trainees. Methods  Six sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A far lateral craniotomy was performed by each of three neurosurgery resident/fellow at varying stages of training. The study objective was the completion and photodocumentation of the craniotomy to accompany a stepwise description of the exposure to provide a comprehensive, intelligible, and anatomically oriented resource for trainees at any level. Illustrative case examples were prepared to supplement approach dissections. Results  The far lateral approach provides a wide and versatile corridor for posterior fossa operation, with access spanning the entire cerebellopontine angle (CPA), foramen magnum, and upper cervical region. Key Steps Include  The study includes the following steps: positioning and skin incision, myocutaneous flap, placement of burr holes and sigmoid trough, fashioning of the craniotomy bone flap, bilateral C1 laminectomy, occipital condyle/jugular tubercle drilling, and dural opening. Conclusion  Although more cumbersome than the retrosigmoid approach, a far lateral craniotomy offers unparalleled access to lesions centered lower or more medially in the CPA, as well as those with significant extension into the clival or foramen magnum regions. Dissection-based neuroanatomic guides to operative approaches provide a unique and rich resource for trainees to comprehend, prepare for, practice, and perform complex cranial operations, such as the far lateral craniotomy.

Academically Inclined: Predictors of Early Career Trajectory and Avenues for Early Intervention Among Neurosurgery Trainees

BACKGROUND

The relationship of academic activities before and during neurosurgery residency with fellowship or career outcomes has not been studied completely.

OBJECTIVE

To assess possible predictors of fellowship and career outcomes among neurosurgery residents.

METHODS

US neurosurgery graduates (2018-2020) were assessed retrospectively for peer-reviewed citations of preresidency vs intraresidency publications, author order, and article type. Additional parameters included medical school, residency program, degree (MD vs DO; PhD), postgraduate fellowship, and academic employment.

RESULTS

Of 547 neurosurgeons, 334 (61.1%) entered fellowships. Fellowship training was significantly associated with medical school rank and first-author publications. Individuals from medical schools ranked 1 to 50 were 1.6 times more likely to become postgraduate fellows than individuals from medical schools ranked 51 to 92 (odds ratio [OR], 1.63 [95% CI 1.04-2.56]; P = .03). Residents with ≥2 first-author publications were almost twice as likely to complete a fellowship as individuals with <2 first-author publications (OR, 1.91 [95% CI 1.21-3.03]; P = .006). Among 522 graduates with employment data available, academic employment obtained by 257 (49.2%) was significantly associated with fellowship training and all publication-specific variables. Fellowship-trained graduates were twice as likely to pursue academic careers (OR, 1.99 [95% CI 1.34-2.96]; P < .001) as were individuals with ≥3 first-author publications ( P < .001), ≥2 laboratory publications ( P = .04), or ≥9 clinical publications ( P < .001).

CONCLUSION

Research productivity, medical school rank, and fellowships are independently associated with academic career outcomes of neurosurgeons. Academically inclined residents may benefit from early access to mentorship, sponsorship, and publishing opportunities.