Objectives The abducens nerve has a long, serpentine subarachnoid course with complex topographical relationships, rendering abducens nerve palsy the most common ocular motor cranial nerve palsy in adults and second most common in pediatric patients, with anatomical variants reported in the literature. Preoperative awareness of abducens nerve variant anatomy may help prevent inadvertent intraoperative injury. Design This study is a case report with a review of the abducens nerve anatomy and variants. Setting The study setting included outpatient, inpatient, and operating room in the neurosurgery department of a quaternary referral center. Participants The study included a woman in her early 30s with a diagnosis of petrous meningioma. Main Outcome Measures In vivo documentation of a type 3 abducens nerve duplication was carried out. Results A left extended retrosigmoid craniotomy was recommended for the petroclival meningioma resection. Intraoperatively, a complete duplication of the left abducens cisternal segment was encountered and photographed. The left unilateral abducens nerve duplication was confirmed with postoperative volumetric magnetic resonance imaging using the FIESTA (fast imaging employing steady-state acquisition) sequence, revealing the union of the duplicated cisternal abducens nerves into a single trunk from Dorello's canal distally. Conclusions Abducens nerve variants are uncommon, and although reported in the setting of cadaveric dissection, in vivo documentation of them is limited. This case report of an in vivo type 3 abducens nerve duplication with intraoperative photographic and radiographic images highlights the need for clinical awareness to avoid inadvertent intraoperative injury.
{"title":"Abducens Nerve Duplication: Novel Intraoperative and Radiographic Observation of a Rare Anatomical Variant","authors":"","doi":"10.1055/s-0044-1779736","DOIUrl":"https://doi.org/10.1055/s-0044-1779736","url":null,"abstract":"Objectives The abducens nerve has a long, serpentine subarachnoid course with complex topographical relationships, rendering abducens nerve palsy the most common ocular motor cranial nerve palsy in adults and second most common in pediatric patients, with anatomical variants reported in the literature. Preoperative awareness of abducens nerve variant anatomy may help prevent inadvertent intraoperative injury. Design This study is a case report with a review of the abducens nerve anatomy and variants. Setting The study setting included outpatient, inpatient, and operating room in the neurosurgery department of a quaternary referral center. Participants The study included a woman in her early 30s with a diagnosis of petrous meningioma. Main Outcome Measures In vivo documentation of a type 3 abducens nerve duplication was carried out. Results A left extended retrosigmoid craniotomy was recommended for the petroclival meningioma resection. Intraoperatively, a complete duplication of the left abducens cisternal segment was encountered and photographed. The left unilateral abducens nerve duplication was confirmed with postoperative volumetric magnetic resonance imaging using the FIESTA (fast imaging employing steady-state acquisition) sequence, revealing the union of the duplicated cisternal abducens nerves into a single trunk from Dorello's canal distally. Conclusions Abducens nerve variants are uncommon, and although reported in the setting of cadaveric dissection, in vivo documentation of them is limited. This case report of an in vivo type 3 abducens nerve duplication with intraoperative photographic and radiographic images highlights the need for clinical awareness to avoid inadvertent intraoperative injury.","PeriodicalId":16513,"journal":{"name":"Journal of Neurological Surgery Part B: Skull Base","volume":"33 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140017332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Objectives In this research, the authors provide a retrospective cohort study of 82 patients with suprasellar meningiomas to identify predictors of the visual outcome following surgery. We also conducted a matched retrospective case–control analysis. Methods This retrospective cohort study included all patients who underwent craniotomy for surgical excision of suprasellar meningiomas at our institution between January 2016 and March 2022. We designed a matched case–control study for patients with and without early intradural optic canal decompression (IOCD). We also developed a machine learning model to have the best possible sensitivity for the prediction of visual recovery after surgery. Results The visual acuity score (VAS) improved in 46.3% of our cases and decreased in 7.4% of the 82 included cases postoperatively. The VAS did not change in 46.3% of the patients after surgery. Statistically, visual complaints, optic atrophy, tuberculum sella involvement, and olfactory groove involvement were associated with lower preoperative VAS and visual field index (VFI). Only intracavernous sinus (ICS) extension and intraoperative vascular involvement were significantly associated with lower postoperative mean VAS correction. The outcome analysis revealed that the improvement in VAS and VFI after surgery was not statistically different between the groups with and without early IOCD (p-value = 1). Conclusion ICS extension was the only location-related factor associated with increased tumor recurrence or regrowth, which makes postoperative radiotherapy more valuable in patients with cavernous sinus extension. Our study results did not support the efficacy of early IOCD in increasing postoperative VAS and VFI.
{"title":"Visual Outcomes after Suprasellar Meningioma Resection: A Retrospective Cohort Study and a Machine Learning-Based Predictive Model","authors":"","doi":"10.1055/s-0044-1779671","DOIUrl":"https://doi.org/10.1055/s-0044-1779671","url":null,"abstract":"Objectives In this research, the authors provide a retrospective cohort study of 82 patients with suprasellar meningiomas to identify predictors of the visual outcome following surgery. We also conducted a matched retrospective case–control analysis. Methods This retrospective cohort study included all patients who underwent craniotomy for surgical excision of suprasellar meningiomas at our institution between January 2016 and March 2022. We designed a matched case–control study for patients with and without early intradural optic canal decompression (IOCD). We also developed a machine learning model to have the best possible sensitivity for the prediction of visual recovery after surgery. Results The visual acuity score (VAS) improved in 46.3% of our cases and decreased in 7.4% of the 82 included cases postoperatively. The VAS did not change in 46.3% of the patients after surgery. Statistically, visual complaints, optic atrophy, tuberculum sella involvement, and olfactory groove involvement were associated with lower preoperative VAS and visual field index (VFI). Only intracavernous sinus (ICS) extension and intraoperative vascular involvement were significantly associated with lower postoperative mean VAS correction. The outcome analysis revealed that the improvement in VAS and VFI after surgery was not statistically different between the groups with and without early IOCD (p-value = 1). Conclusion ICS extension was the only location-related factor associated with increased tumor recurrence or regrowth, which makes postoperative radiotherapy more valuable in patients with cavernous sinus extension. Our study results did not support the efficacy of early IOCD in increasing postoperative VAS and VFI.","PeriodicalId":16513,"journal":{"name":"Journal of Neurological Surgery Part B: Skull Base","volume":"27 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139957048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}