Immersive virtual reality as a surgical training tool: A cohort study.

Background: Few studies have studied the efficacy of using immersive virtual reality (iVR) to teach surgical skills, especially by using real-world iVR recordings rather than simulations. This study aimed to investigate whether viewing 360° iVR instructional recordings produces greater improvements in basic suturing skills of students without prior medical training, beyond traditional methods like reading written manuals or watching 2D instructional videos. Materials and methods: This was a partially blinded randomized cohort study. 44 pre-university students (aged 17) were randomized equally to either the written instruction manual, 2D instructional video, or iVR recordings. All students first watched a silent 2D demonstration video of the suturing task, before attempting to place three simple interrupted sutures on a piece of meat as a baseline. The time taken for the first attempt was recorded. Students were then given an hour to train using their allocated modality. They attempted the suturing task again, and timings were re-recorded. Four blinded surgically-trained judges independently assessed the quality of the stitches placed both pre and post-intervention. One-way analysis of variance tests (ANOVAs) and independent two-sample t-tests were used to determine the effect of training modality on improvements in suturing scores and time taken to complete suturing from pre to post-training. Results: For suturing scores, the iVR group showed significantly larger score improvements than the Written Manual group (p = 0.031, Cohen's D = 0.92), while this iVR advantage was less pronounced when compared with the 2D Video group (p = 0.16, Cohen's D = 0.65). Similarly for time taken to complete suturing, the iVR group had significantly larger time improvements than the Written Manual group (p = 0.045), although this difference was less robust compared to the 2D Instructional Video group (p = 0.34). Conclusion: This study demonstrates that iVR training using real-world 360° instructional recordings produced significantly greater training gains in suturing scores and efficiency compared to reading written text. iVR training also led to larger training gains in both outcome measures than viewing 2D instructional videos, although the differences between them did not reach statistical significance.

Intra-operative extracorporeal irradiation of tumour-invaded craniotomy bone flap in meningioma: a case series.

BACKGROUND: Extracorporeal irradiation of tumorous calvaria (EITC) can be performed to restore function and form of the skull after resection of bone-invasive meningioma. We sought to examine the rate of tumour recurrence and other selected outcomes in patients undergoing meningioma resection and EITC. METHODS: Retrospective single-centre study of adult patients undergoing meningioma resection and EITC between January 2015 and November 2022 at a tertiary neurosurgical centre. Patient demographics, surgery data, tumour data, use of adjuvant therapy, surgical complications, and tumour recurrences were collected. RESULTS: Eighteen patients with 11 (61%) CNS WHO grade 1, 6 (33%) grade 2, and 1 (6%) grade 3 meningiomas were included. Median follow-up was 42 months (range 3-88). Five (28%) patients had a recurrence, but none were associated with the bone flap. Two (11%) wound infections requiring explant surgery occurred. Six (33%) patients required a further operation. Two operations were for recurrences, one was for infection, one was a washout and wound exploration but no evidence of infection was found, one patient requested the removal of a small titanium implant, and one patient required a ventriculoperitoneal shunt for a persistent CSF collection. There were no cases of bone flap resorption and cosmetic outcome was not routinely recorded. CONCLUSION: EITC is feasible and fast to perform with good outcomes and cost-effectiveness compared to other reconstructive methods. We observed similar recurrence rates and lower infection rates requiring explant compared to the largest series of cranioplasty in meningioma. Cosmetic outcome is universally under-reported and should be reported in future studies.

Technical considerations and long-term results of endovascular venous stenting to control venous hypertension from meningiomas invading intracranial venous sinuses.

OBJECTIVE: Meningiomas invading the intracranial venous sinuses may cause intracranial venous hypertension, papilledema, and visual compromise. Sinus resection and graft reconstructions, however, add significant complexity to tumor surgery, with the potential for increased morbidity. In this study, the authors explored whether venous sinus stenting might provide an alternative means of controlling venous hypertension that would be sustainable over the long term. METHODS: The authors performed a retrospective review of all 16 patients with intracranial meningiomas who underwent stenting at their institution for venous sinus compromise. At presentation, all had headache and 9 had papilledema. Thirteen patients had 1 meningioma and 3 had 2 or more. Three patients had had previous tumor resection and radiotherapy. One patient had been treated with a lumboperitoneal shunt and radiotherapy. The median length of clinical follow-up was 8 years (range 4 months-18 years). RESULTS: Venous sinus narrowing was often not confined to the site of meningioma, and bilateral transverse sinus narrowing, reminiscent of that seen in idiopathic intracranial hypertension, was present in 7 patients with sagittal sinus meningiomas. Eleven patients had stents placed solely across sinus narrowing caused by meningioma. Five patients had additional stents placed at other sites of venous narrowing at the same time: in one of these patients, a stent was placed across a defect in the sagittal sinus caused by previous surgery, and in the 4 other patients, stents were placed across nontumor narrowings of the transverse sinuses. In 1 patient, the jugular vein was also stented. Nine patients developed symptomatic in-stent restenosis at the meningioma site. Eight had further stenting procedures with variable success in restoring the in-stent lumen. The remaining patient, with a late partial relapse, is being reinvestigated. Papilledema resolved in all patients after stenting. Six patients experienced prolonged and very substantial relief of all symptoms. Five patients had persistent headache despite restoration of the sinus lumen. Five had persistent symptoms associated with resistant in-stent stenosis. There were no significant complications from any of the diagnostic or therapeutic procedures. CONCLUSIONS: In patients who are symptomatic with meningiomas obstructing the venous sinuses, successful stenting of the affected segment can give a good outcome, especially in terms of relieving papilledema. However, further procedures are often necessary to maintain stent patency, other areas of venous compromise frequently coexist, and some patients remain symptomatic despite apparently successful treatment of the index lesion. Long-term surveillance is a requirement.

Antiplatelet therapy in aneurysmal subarachnoid hemorrhage: an updated meta-analysis.

Antiplatelet therapy (AT) may serve to reduce the effects of aneurysmal subarachnoid hemorrhage (aSAH)-induced pro-coagulant state in the cerebral circulation. Several studies, however, have delivered conflicting conclusions on the efficacy of AT post aSAH. Systematic searches of Medline, Embase, and Cochrane Central were undertaken on 27th March 2023. The primary outcome was delayed cerebral ischaemia (DCI). Secondary outcomes were symptomatic and angiographic vasospasm, good functional outcome (modified Rankin Scale [mRS] with scores 0-2), hemorrhagic events, and in-hospital mortality. Twenty-two studies reporting 4378 patients with aSAH were included in the meta-analysis. AT was associated with lower rates of DCI (RR=0.62, 95% CI: 0.43; 0.89), symptomatic vasospasm (RR=0.63, 95% CI: 0.46; 0.86), and moderate/severe angiographic vasospasm (RR=0.74, 95% CI: 0.65; 0.84), with no effect on hemorrhagic complications (RR=1.36, 95% CI: 0.77; 2.41). When analyzing only post-ictal use of AT, AT additionally favored rates of good functional outcomes (RR=1.18, 95% CI: 1.10; 1.26) and in-hospital mortality (RR=0.56, 95% CI: 0.39; 0.80). In the subgroup treated with cilostazol, AT was associated with lower rates of DCI (RR=0.40, 95% CI: 0.32), symptomatic vasospasm (RR=0.47, 95% CI: 0.33; 0.65), moderate/severe angiographic vasospasm (RR=0.75, 95% CI: 0.57; 0.98) and good functional outcome (RR=1.24, 95% CI: 1.08; 1.43). In the surgically treated aSAH subgroup, AT favored rates of symptomatic vasospasm (RR=0.55, 95% CI: 0.30; 0.98), moderate/severe angiographic vasospasm (RR=0.70, 95% CI: 0.54; 0.90) and good functional outcome (RR=1.23, 95% CI: 1.09; 1.41). In the endovascularly treated aSAH subgroup, AT was associated with lower rates of in-hospital mortality (RR=0.60, 95% CI: 0.41; 0.88). In aSAH patients, post-ictal AT is associated with benefits in terms of rates of DCI, vasospasm, good functional outcomes, and in-hospital mortality without an increased risk of hemorrhagic events.

Results of Surgical Treatment of Aneurysmal Subarachnoid Hemorrhage in a Single Institution Over 12 Years.

OBJECTIVE: For patients with aneurysmal subarachnoid hemorrhage (aSAH) in whom endovascular treatment is not the optimal treatment strategy, microsurgical clipping remains a viable option. We examined changes in morbidity and outcome over time in patients treated surgically and in relation to surgeon volume and experience. METHODS: All patients who underwent microsurgery for aSAH from 2007 to 2019 at our institution were included. We compared technical complication rates and surgical outcomes between experienced (≥50 independent cases) and inexperienced (<50 independent cases) surgeons and between high-volume (≥20 cases/year) and low-volume (<20 cases/year) surgeons. RESULTS: Most of the 1,003 aneurysms (970 patients, median age 56 years) were in the middle cerebral (41.4%), anterior communicating (27.6%), and posterior communicating (17.5%) arteries; 46.5% were <7 mm. The technical complication rate was 7%, resulting in postoperative infarct in 4.9% of patients. Nineteen patients (2%) died within 30 days of admission. There were no significant changes in rates of technical complication, postoperative infarct, or mortality over the study period. There were no differences in postoperative infarction and technical complication rates between experienced and inexperienced surgeons (P = 0.28 and P = 0.05, respectively), but there were differences when comparing high-volume and low-volume surgeons (P = 0.03 and P < 0.001, respectively). The independent predictors of postoperative infarctions were aneurysm size (P = 0.001), intraoperative large-vessel injury (P < 0.001), and low surgeon volume (P = 0.03). CONCLUSIONS: We present real-world data on surgical morbidity and outcomes after aSAH. We demonstrated a relationship between surgeon volume and outcome for surgical treatment of aSAH, which supports the benefit of subspecialization in cerebrovascular surgery.

Use of Mixed Reality in Neurosurgery Training: A Single Centre Experience.

BACKGROUND: Mixed reality (MR) technology has opened new avenues for planning, visualization, and education in surgery. Neurosurgical pathologies require a very clear understanding of the relationships between pathology and critical neurovascular structures. The decline in cadaveric dissections and resource constraints has pushed the educators to find newer ways of rendering the same knowledge. The aim of this study was to determine the feasibility of employing a MR device in a high-volume center for neurosurgical teaching. The study also evaluated the results of the trainee experience in using the MR platform. METHODS: Three neurosurgical consultants who are part of the teaching faculty were asked to facilitate the session. No prior training on utilizing the MR device was given to the trainees. HoloLens 2 was used as the MR device. Two questionnaires were used to understand the experience of the trainees. RESULTS: Eight active neurosurgical trainees who are currently training at our institution were recruited for the purposes of this study. Despite having no prior training on a MR platform, the learning curve was short for most of the trainees. Whether MR replace current traditional methods of teaching neuroanatomy, the response was divided across the trainees. The results of the User Experience Questionnaire were positive with the trainees finding the device as attractive, dependable, novel, and user-friendly. CONCLUSION: This study demonstrates the feasibility of using MR platform in neurosurgery training without significant preparation requirements. These data are required to justify the future investment in this technology for training institutions.

Comparison of health-related quality of life in patients with traumatic brain injury, subarachnoid haemorrhage and cervical spine disease.

PURPOSE: The degree of disability that is acceptable to patients following traumatic brain injury (TBI) continues to be debated. While the dichotomization of outcome on the Glasgow Outcome Score (GOSE) into 'favourable' and 'unfavourable' continues to guide clinical decisions, this may not reflect an individual's subjective experience. The aim of this study is to assess how patients' self-reported quality of life (QoL) relates to objective outcome assessments and how it compares to other debilitating neurosurgical pathologies, including subarachnoid haemorrhage (SAH) and cervical myelopathy. METHOD: A retrospective analysis of over 1300 patients seen in Addenbrooke's Hospital, Cambridge, UK with TBI, SAH and patients pre- and post- cervical surgery was performed. QoL was assessed using the SF-36 questionnaire. Kruskal-Wallis test was used to analyse the difference in SF-36 domain scores between the four unpaired patient groups. To determine how the point of dichotomization of GOSE into 'favourable' and 'unfavourable' outcome affected QOL, SF-36 scores were compared between GOSE and mRS. RESULTS: There was a statistically significant difference in the median Physical Component Score (PCS) and Mental Component Score (MCS) of SF-36 between the three neurosurgical pathologies. Patients with TBI and SAH scored higher on most SF-36 domains when compared with cervical myelopathy patients in the severe category. While patients with Upper Severe Disability on GOSE showed significantly higher PC and MC scores compared to GOSE 3, there was a significant degree of variability in individual responses across the groups. CONCLUSION: A significant number of patients following TBI and SAH have better self-reported QOL than cervical spine patients and patients' subjective perception and expectations following injury do not always correspond to objective disability. These results can guide discussion of treatment and outcomes with patients and families.

Impact of Intraoperative Magnetic Resonance Imaging on Short-Term and Long-Term Outcomes After Transsphenoidal Resection of Pituitary Adenoma: A Systematic Review and Meta-Analysis.

BACKGROUND: Intraoperative magnetic resonance imaging (iMRI) allows for greater tumor visualization and extent of resection. It is increasingly used in transsphenoidal surgeries but its role is not yet established. OBJECTIVE: We aimed to clarify the usefulness of iMRI in transsphenoidal surgery using direct statistical comparisons, with additional subgroup and regression analyses to investigate which patients benefit the most from iMRI use. METHODS: Systematic searches of PubMed, Embase, and Cochrane Central were undertaken from database inception to May 2020 for published studies reporting the outcomes of iMRI use in transsphenoidal resection of pituitary adenoma. RESULTS: Thirty-three studies reporting 2106 transsphenoidal surgeries in 2099 patients were included. Of these surgeries, 1487 (70.6%) were for nonfunctioning pituitary adenomas, whereas 619 (29.4%) were for functioning adenomas. Pooled gross total resection (GTR) was 47.6% without iMRI and 66.8% with iMRI (risk ratio [RR], 1.32; P < 0.001). Subgroup and meta-regression analyses demonstrated comparable increases in GTR between microscopic (RR, 1.35; P < 0.001) and endoscopic (RR, 1.31; P < 0.001) approaches as well as functioning and nonfunctioning adenomas (P = 0.584). The pooled rate of hypersecretion normalization was 73.0% within 3 months and 51.7% beyond 3 months postoperatively. The pooled rate of short-term and long-term improvement in visual symptoms was 96.5% and 84.9%, respectively. The incidence of postoperative surgical complications was low. The pooled reoperation rate was 3.8% across 1106 patients. CONCLUSIONS: The use of iMRI as an adjunct significantly increases GTR for both microscopic and endoscopic resection of pituitary adenomas, with comparable benefits for both functioning and nonfunctioning adenomas. Satisfactory endocrinologic and visual outcomes were achieved.

Stereotactic Neurosurgical Robotics With Real-Time Patient Tracking: A Cadaveric Study.

BACKGROUND: Robotic neurosurgery may improve the accuracy, speed, and availability of stereotactic procedures. We recently developed a computer vision and artificial intelligence-driven frameless stereotaxy for nonimmobilized patients, creating an opportunity to develop accurate and rapidly deployable robots for bedside cranial intervention. OBJECTIVE: To validate a portable stereotactic surgical robot capable of frameless registration, real-time tracking, and accurate bedside catheter placement. METHODS: Four human cadavers were used to evaluate the robot's ability to maintain low surface registration and targeting error for 72 intracranial targets during head motion, ie, without rigid cranial fixation. Twenty-four intracranial catheters were placed robotically at predetermined targets. Placement accuracy was verified by computed tomography imaging. RESULTS: Robotic tracking of the moving cadaver heads occurred with a program runtime of 0.111 ± 0.013 seconds, and the movement command latency was only 0.002 ± 0.003 seconds. For surface error tracking, the robot sustained a 0.588 ± 0.105 mm registration accuracy during dynamic head motions (velocity of 6.647 ± 2.360 cm/s). For the 24 robotic-assisted intracranial catheter placements, the target registration error was 0.848 ± 0.590 mm, providing a user error of 0.339 ± 0.179 mm. CONCLUSION: Robotic-assisted stereotactic procedures on mobile subjects were feasible with this robot and computer vision image guidance technology. Frameless robotic neurosurgery potentiates surgery on nonimmobilized and awake patients both in the operating room and at the bedside. It can affect the field through improving the safety and ability to perform procedures such as ventriculostomy, stereo electroencephalography, biopsy, and potentially other novel procedures. If we envision catheter misplacement as a "never event," robotics can facilitate that reality.

Relevance of presenting risks of frailty, sarcopaenia and osteopaenia to outcomes from aneurysmal subarachnoid haemorrhage.

INTRODUCTION: Aneurysmal subarachnoid haemorrhage (aSAH) is a condition with significant morbidity and mortality. Traditional markers of aSAH have established their utility in the prediction of aSAH outcomes while frailty markers have been validated in other surgical specialties. We aimed to compare the predictive value of frailty indices and markers of sarcopaenia and osteopaenia, against the traditional markers for aSAH outcomes. METHODS: An observational study in a tertiary neurosurgical unit on 51 consecutive patients with ruptured aSAH was performed. The best performing marker in predicting the modified Rankin scale (mRS) on discharge was selected and an appropriate threshold for the definition of frail and non-frail was derived. We compared various frailty indices (modified frailty index 11, and 5, and the National Surgical Quality Improvement Program score [NSQIP]) and markers of sarcopaenia and osteopaenia (temporalis [TMT] and zygoma thickness), against traditional markers (age, World Federation of Neurological Surgery and modified Fisher scale [MFS]) for aSAH outcomes. Univariable and multivariable analysis was then performed for various inpatient and long-term outcomes. RESULTS: TMT was the best performing marker in our cohort with an AUC of 0.82, Somers' D statistic of 0.63 and Tau statistic 0.25. Of the frailty scores, the NSQIP performed the best (AUC 0.69), at levels comparable to traditional markers of aSAH, such as MFS (AUC 0.68). The threshold of 5.5 mm in TMT thickness was found to have a specificity of 0.93, sensitivity of 0.51, positive predictive value of 0.95 and negative predictive value of 0.42. After multivariate analysis, patients with TMT ≥ 5.5 mm (defined as non-frail), were less likely to experience delayed cerebral ischaemia (OR 0.11 [0.01 - 0.93], p = 0.042), any complications (OR 0.20 [0.06 - 0.069], p = 0.011), and had a larger proportion of favourable mRS on discharge (95.0% vs. 58.1%, p = 0.024) and at 3-months (95.0% vs. 64.5%, p = 0.048). However, the gap between unfavourable and favourable mRS was insignificant at the comparison of 1-year outcomes. CONCLUSION: TMT, as a marker of sarcopaenia, correlated well with the presenting status, and outcomes of aSAH. Frailty, as defined by NSQIP, performed at levels equivalent to aSAH scores of clinical relevance, suggesting that, in patients presenting with acute brain injury, both non-neurological and neurological factors were complementary in the determination of eventual clinical outcomes. Further validation of these markers, in addition to exploration of other relevant frailty indices, may help to better prognosticate aSAH outcomes and allow for a precision medicine approach to decision making and optimization of best outcomes.

Gods and monsters: Greek mythology and Christian references in the neurosurgical lexicon.

BACKGROUND: Myths and religion are belief systems centered around supernatural entities that attempt to explain the observed world and are of high importance to certain communities. The former is a collection of stories that belong to a cultural tradition and the latter are organized faiths that determine codes of ethics, rituals and philosophy. Deities or monstrous creatures in particular act as archetypes instructing an individual's conduct. References to them in Greek mythology and Christianity are frequently manifested in the modern neurosurgical vernacular. METHODS: A review of the medical literature was performed using the PubMed and MEDLINE bibliographic databases. Publications from 1875 to 2021 related to neurosurgery or neuroanatomy with the medical subject headings (MeSH) terms mythology, religion, Christianity and Catholicism were reviewed. References pertaining to supernatural beings were classified to either a deity or a monstrosity according to their conventional cultural context. RESULTS: Twelve narratives associated with neurosurgery were identified, nine relating to Greek mythology and three associated with the Christian-Catholic faith. Eight accounts concerned deities and the remaining with monstrous creatures. CONCLUSION: This article explores the etymology of commonly utilized terms in daily neurosurgical practice in the context of mythology and religion. They reveal the ingenuity and creativity of early pioneers who strived to understand the brain.

A systematic review and meta-analysis of the association between cyproterone acetate and intracranial meningiomas.

The influence of exposure to hormonal treatments, particularly cyproterone acetate (CPA), has been posited to contribute to the growth of meningiomas. Given the widespread use of CPA, this systematic review and meta-analysis attempted to assess real-world evidence of the association between CPA and the occurrence of intracranial meningiomas. Systematic searches of Ovid MEDLINE, Embase and Cochrane Controlled Register of Controlled Trials, were performed from database inception to 18th December 2021. Four retrospective observational studies reporting 8,132,348 patients were included in the meta-analysis. There was a total of 165,988 subjects with usage of CPA. The age of patients at meningioma diagnosis was generally above 45 years in all studies. The dosage of CPA taken by the exposed group (n = 165,988) was specified in three of the four included studies. All studies that analyzed high versus low dose CPA found a significant association between high dose CPA usage and increased risk of meningioma. When high and low dose patients were grouped together, there was no statistically significant increase in risk of meningioma associated with use of CPA (RR = 3.78 [95% CI 0.31-46.39], p = 0.190). Usage of CPA is associated with increased risk of meningioma at high doses but not when low doses are also included. Routine screening and meningioma surveillance by brain MRI offered to patients prescribed with CPA is likely a reasonable clinical consideration if given at high doses for long periods of time. Our findings highlight the need for further research on this topic.

Paediatric Cerebral Arteriovenous Malformation: Outcomes from a Singapore Children's Hospital.

OBJECTIVES: Paediatric brain arteriovenous malformation (bAVM) is a rare and distinct clinical entity. There is a growing body of literature that support the success of multimodality approaches for this difficult condition. The authors aim to firstly, describe our institutional experience with a consecutive series of patients and next, corroborate our results with current literature. MATERIAL AND METHODS: This is a single institution, retrospective study conducted over a 20-year period. Patients less than 19 years old with bAVM were included. Variables of interest included patient demographics, clinical presentation, neuroimaging features, bAVM characteristics and treatment modality. Functional outcomes were measured with modified Rankin scale (mRS). RESULTS: There were 58 paediatric bAVMs, presenting at a mean age of 8.7 ± 4.2 years, and followed up for a mean duration of 7.7 years. Thirty-six patients (62.1%) underwent microsurgical resection, 10 patients had stereotactic radiosurgery (17.2%) and 2 patients had endovascular treatment (3.4%). 50 patients (86.2%) had a favourable outcome at 1-year follow up. Microsurgical resection and SRS had similar obliteration rates (resection 83.3%; SRS 80.0%) and recurrence (resection 10.0%; SRS 12.5%). There were 6 cases of bAVM recurrence (12.8%). This subgroup was noted to be less than 7.5 years old at presentation (OR 15.0, 95% CI 1.56 - 144), and less likely to present with bAVM rupture (OR 0.11, 95% CI 0.01 - 0.96). CONCLUSION: This study describes our experience in managing paediatric bAVM, whereby monomodal therapy can still be effective. Of note, we also demonstrate the role of extended surveillance to detect recurrence.

Endoscopic excision of an aqueduct of Sylvius cavernoma causing obstructive hydrocephalus: technical note.

BACKGROUND AND IMPORTANCE: Acquired lesions within the aqueduct of Sylvius are rare and their surgical management is challenging. Open transcranial approaches require dissection and manipulation of surrounding eloquent structures. Use of an endoscope can avoid potential morbidity from traversing and handling eloquent structures during open approaches whilst providing better visualisation of an intraventricular lesion. CLINICAL PRESENTATION: A 62-year-old female presented with insidious onset short-term memory loss, unsteady gait, urinary incontinence and left-sided dysaesthesia. Magnetic resonance imaging (MRI) revealed hydrocephalus from an obstructive haemorrhagic lesion consistent with a cavernoma at the central midbrain within the aqueduct of Sylvius. An endoscopic approach was selected to provide optimal visualisation of the lesion. As only a single instrument could be accommodated, rotational movements were employed to tease out the lesion. Gross total resection was achieved. Her symptoms improved immediately postoperatively and she made a complete recovery by 2 months. Post-operative MRI showed resolution of hydrocephalus and no evidence of residual/recurrence of the lesion. Unfortunately, she developed hydrocephalus 3 months post-op and required placement of a ventriculoperitoneal shunt. CONCLUSIONS: Endoscopic resection is safe and feasible for selected periaqueductal lesions as it provides direct access while minimising disruption of the surrounding anatomical structures. The limitation of only having a single instrument can be overcome by employing rotational movements.

Long-term oncological outcomes after haemorrhagic apoplexy in pituitary adenoma managed operatively and non-operatively.

INTRODUCTION: Depending on severity of presentation, pituitary apoplexy can be managed with acute surgery or non-operatively. We aim to assess long-term tumour control, visual and endocrinological outcomes following pituitary apoplexy with special emphasis on patients treated non-operatively. METHODS: Multicentre retrospective cohort study. All patients with symptomatic pituitary apoplexy were included. Patients were divided into 3 groups: group 1: surgery within 7 days; group 2: surgery 7 days-3 months; group 3: non-operative. Further intervention for oncological reasons during follow-up was the primary outcome. Secondary outcome measures included visual and endocrinological function at last follow-up. RESULTS: One hundred sixty patients were identified with mean follow-up of 48 months (n = 61 group 1; n = 34 group 2; n = 64 group 3). Factors influencing decision for surgical treatment included visual acuity loss (OR: 2.50; 95% CI: 1.02-6.10), oculomotor nerve palsy (OR: 2.80; 95% CI: 1.08-7.25) and compression of chiasm on imaging (OR: 9.50; 95% CI: 2.06-43.73). Treatment for tumour progression/recurrence was required in 17%, 37% and 24% in groups 1, 2 and 3, respectively (p = 0.07). Urgent surgery (OR: 0.16; 95% CI: 0.04-0.59) and tumour regression on follow-up (OR: 0.04; 95% CI: 0.04-0.36) were independently associated with long-term tumour control. Visual and endocrinological outcomes were comparable between groups. CONCLUSION: Urgent surgery is an independent predictor of long-term tumour control following pituitary apoplexy. However, 76% of patients who successfully complete 3 months of non-operative treatment may not require any intervention in the long term.

Far Lateral Approaches: C1 Meningioma With Vertebral Artery Involvement: 3-Dimensional Operative Video.

Tumors around the cervicomedullary junction are rare and constitute 5% of spinal tumors and 1% of cranial tumors. The approach to these lesions is difficult because of the close proximity of the medulla and cervical spinal cord, lower cranial nerves, and vertebral artery (VA) as well as the complex articulation between occipital condyle, C1 and C2. Cervicomedullary junction meningiomas are commonly classified based on their origin in relation to the dentate ligament, but the relationship to the VA typically plays an important role in deciding the surgical approach. For lesions located dorsal to the dentate ligament and not involving the VA, a midline approach is typically sufficient. However, when the VA is involved a far lateral approach is preferred as it offers better access to the V4 segment. We describe a case of a 55-yr-old man who presented with accessory nerve palsy and mild upper motor neuron signs and was found to have a C1 meningioma encasing and narrowing the VA at the V3/V4 segment. Informed consent was obtained. The patient was treated with a right far lateral approach with limited condylectomy to gain access to the V4 segment. We described the steps used for safe resection of the tumor around the VA from distal to proximal. We demonstrate the relationship of the tumor to the VA and the need to completely skeletonize the VA to achieve a gross total resection. We supplement the discussion with a 3D surgical video.

Far Lateral Approaches: Far Lateral Approach With Minimal Condylectomy for C2 Schwannoma: 3-Dimensional Operative Video.

Upper cervical schwannomas are rare lesions and together with meningiomas constitute around 5% of spinal tumors. The approach to these lesions is difficult because of the close proximity of the medulla and cervical spinal cord, lower cranial nerves, and the vertebral artery. Schwannomas in the upper cervical area typically arise from the dorsal roots and are located posterior to the dentate ligament. Nevertheless, a far lateral approach is often required for these lesions because of their lateral extent through the neural foramen and the proximity of both the V3 and V4 segments of the vertebral artery. With these lesions, an extensive condylectomy is rarely required. We present a case of a 40-yr-old woman who presented with an 8-mo history of deteriorating mobility and feeling of heaviness in the lower limbs with a further acute deterioration 1 wk before admission. She had a dissociated sensory loss and myelopathy in keeping with a partial hemicord syndrome. Imaging revealed a right-sided C2 intradural lesion extending through the C2 foramen in keeping with a C2 schwannoma. The patient was counseled on the treatment options, and informed consent for surgery was obtained. We describe a right-sided far lateral approach with minimal condylectomy for gross total resection of this lesion. We demonstrate the relationship of the tumor with the C2 nerve root, the spinal accessory nerve, and the cervical cord. We supplement the discussion with a 3D surgical video.

Far Lateral Approaches: Dural Arteriovenous Fistulae at the Hypoglossal Canal: 3-Dimensional Operative Video.

Cognard type V dural arteriovenous fistulae (dAVF) are typically located at the foramen magnum. Their presentation often mimics that of cervical myelopathy, and they can be easily misdiagnosed even if spinal vascular imaging is undertaken. Treatment typically involves endovascular embolization or surgery when embolization is not possible. We describe a case of a 67-yr-old man who presented with progressive symptoms of cervical myelopathy with a significant reduced ambulation and upper motor neuron signs. Imaging disclosed upper cervical cord edema, and angiography confirmed a Cognard type V dAVF with drainage into the perimedullary and spinal venous system. The dAVF was supplied by the hypoglossal division of the ascending pharyngeal artery. Endovascular treatment was believed to pose a risk of ischemic injury to the hypoglossal nerve, and therefore, surgery was offered. Informed consent was obtained. A far lateral approach was used to access the fistulous point. We describe the relevant vascular anatomy and the benefits of the far lateral approach for this lesion. We also demonstrate a tailored inferior condylectomy to gain access to the intracranial part of the hypoglossal canal, where the draining vein is expected to be found. We supplement the discussion with a 3D surgical video.

The evolution of intracranial aneurysm treatment techniques and future directions.

Treatment techniques and management guidelines for intracranial aneurysms (IAs) have been continually developing and this rapid development has altered treatment decision-making for clinicians. IAs are treated in one of two ways: surgical treatments such as microsurgical clipping with or without bypass techniques, and endovascular methods such as coiling, balloon- or stent-assisted coiling, or intravascular flow diversion and intrasaccular flow disruption. In certain cases, a single approach may be inadequate in completely resolving the IA and successful treatment requires a combination of microsurgical and endovascular techniques, such as in complex aneurysms. The treatment option should be considered based on factors such as age; past medical history; comorbidities; patient preference; aneurysm characteristics such as location, morphology, and size; and finally the operator's experience. The purpose of this review is to provide practicing neurosurgeons with a summary of the techniques available, and to aid decision-making by highlighting ideal or less ideal cases for a given technique. Next, we illustrate the evolution of techniques to overcome the shortfalls of preceding techniques. At the outset, we emphasize that this decision-making process is dynamic and will be directed by current best scientific evidence, and future technological advances.

Frameless neuronavigation with computer vision and real-time tracking for bedside external ventricular drain placement: a cadaveric study.

OBJECTIVE: A major obstacle to improving bedside neurosurgical procedure safety and accuracy with image guidance technologies is the lack of a rapidly deployable, real-time registration and tracking system for a moving patient. This deficiency explains the persistence of freehand placement of external ventricular drains, which has an inherent risk of inaccurate positioning, multiple passes, tract hemorrhage, and injury to adjacent brain parenchyma. Here, the authors introduce and validate a novel image registration and real-time tracking system for frameless stereotactic neuronavigation and catheter placement in the nonimmobilized patient. METHODS: Computer vision technology was used to develop an algorithm that performed near-continuous, automatic, and marker-less image registration. The program fuses a subject's preprocedure CT scans to live 3D camera images (Snap-Surface), and patient movement is incorporated by artificial intelligence-driven recalibration (Real-Track). The surface registration error (SRE) and target registration error (TRE) were calculated for 5 cadaveric heads that underwent serial movements (fast and slow velocity roll, pitch, and yaw motions) and several test conditions, such as surgical draping with limited anatomical exposure and differential subject lighting. Six catheters were placed in each cadaveric head (30 total placements) with a simulated sterile technique. Postprocedure CT scans allowed comparison of planned and actual catheter positions for user error calculation. RESULTS: Registration was successful for all 5 cadaveric specimens, with an overall mean (± standard deviation) SRE of 0.429 ± 0.108 mm for the catheter placements. Accuracy of TRE was maintained under 1.2 mm throughout specimen movements of low and high velocities of roll, pitch, and yaw, with the slowest recalibration time of 0.23 seconds. There were no statistically significant differences in SRE when the specimens were draped or fully undraped (p = 0.336). Performing registration in a bright versus a dimly lit environment had no statistically significant effect on SRE (p = 0.742 and 0.859, respectively). For the catheter placements, mean TRE was 0.862 ± 0.322 mm and mean user error (difference between target and actual catheter tip) was 1.674 ± 1.195 mm. CONCLUSIONS: This computer vision-based registration system provided real-time tracking of cadaveric heads with a recalibration time of less than one-quarter of a second with submillimetric accuracy and enabled catheter placements with millimetric accuracy. Using this approach to guide bedside ventriculostomy could reduce complications, improve safety, and be extrapolated to other frameless stereotactic applications in awake, nonimmobilized patients.