Anterior cervical discectomy and fusion (ACDF) is one of the most commonly performed surgical procedures for the treatment of cervical degenerative disease, myelopathy, radiculopathy, and segmental instability. Although clinical outcomes are generally favorable, pseudarthrosis remains a relevant complication, with a reported incidence ranging from 5% to 20%. In a field with no yet clear main directions, this narrative review aims at giving the reader a broad picture and a wide analysis of the recent advances in cervical spinal fusion, with particular focus on biomaterials, intervertebral cage technologies, cervical spine biomechanics and imaging methods used for fusion assessment. The literature regarding quantitative imaging parameters and emerging applications of artificial intelligence (AI) is also reviewed. Current bone grafts include autologous grafts, allografts, xenografts and polymeric grafts, while the materials for the intervertebral cages comprehend titanium, polyetheretherketone and silicon nitride, with reported fusion rates distributed in a very large range. Computed tomography (CT) remains the standard imaging modality to assess whether fusion has occurred, due to its high spatial resolution. However, the lack of shared diagnostic criteria and the significant interobserver variability continue to limit its reliability. Quantitative parameters, such as Hounsfield Unit measurements and MRI-derived bone quality scores, may contribute to a more objective evaluation, although current evidence remains heterogeneous. In parallel, AI-based imaging analysis is showing promising results for quantitative assessment and longitudinal monitoring of bone fusion; however, large prospective clinical studies are still needed to confirm its clinical applicability. In conclusion, despite advances in surgical technologies and biomaterials, radiological assessment of cervical fusion still lacks universally accepted diagnostic standards. Future AI applications may improve diagnostic accuracy and reproducibility, promoting a more standardized approach in clinical practice.

Background: Accurate pedicle screw placement remains essential in spinal instrumentation, and robotic navigation has been introduced to improve safety, reproducibility, and workflow standardization. This study evaluated the accuracy of robot-assisted pedicle screw placement using the Excelsius GPS platform during the first year of implementation at two centers and analyzed the associated learning curve. Methods: Consecutive patients undergoing robot-assisted spinal instrumentation between April 2024 and April 2025 were retrospectively reviewed. Screw accuracy was assessed on intraoperative three-dimensional imaging using the Gertzbein-Robbins Scale (GRS). Grades A and B were considered clinically acceptable, whereas grades C-E were considered clinically non-acceptable. Sacral S1 screws and oncological cases requiring carbon fiber-reinforced PEEK instrumentation were excluded from the primary analysis and evaluated separately when appropriate. Robotic workflow time was defined as the interval between the first intraoperative three-dimensional acquisition used for planning and the second acquisition used for screw verification. Results: The primary standard non-oncological cohort included 102 patients and 455 non-S1 screws. Overall, 411 screws were classified as GRS A, yielding a perfect intrapedicular placement rate of 90.3%. Clinically acceptable accuracy was achieved in 449 of 455 screws, corresponding to a GRS A + B rate of 98.7% (95% CI, 97.2-99.4%). Only six screws were classified as GRS C-E, with no GRS D screws observed. Clinically acceptable accuracy was comparable between centers. In Center 1, all clinically non-acceptable screws occurred within the first nine cases, and GRS A + B accuracy increased from 92.9% in the first trimester to 100% thereafter. Median robotic workflow time was 64.4 min per case and 13.9 min per screw. Conclusions: This two-center early experience supports the accuracy and reproducibility of ExcelsiusGPS-assisted spinal instrumentation. Chronological analysis showed that clinically non-acceptable breaches were concentrated in the early implementation phase; however, this observation should be considered exploratory because of the low event count. The study supports high clinically acceptable accuracy and broadly comparable robotic workflow metrics across centers. Chronological patterns observed during early implementation should be interpreted as exploratory rather than as proof of a formal learning curve.

Background: Stent screw-assisted internal fixation (SAIF) has been shown to be a valid minimally invasive alternative in the treatment of highgrade osteoporotic and neoplastic fractures presenting with burst morphology, extreme collapse and kyphosis, extensive osteolysis, large pseudoarthrotic clefts, and pedicle or middle column involvement. However, the presence of local deformity and/or posterior tension band injury (as for osteoporotic fracture [OF] 4 and OF 5 fractures, according to the AO Spine-DGOU OF Classification) ideally requires a posterior fixation in addition to an armed kyphoplasty. For these cases, we have built upon our previous work that associates a posterior fixation with a SAIF by actually integrating the SAIF into the posterior fixation construct (SAIF-Rod). Objective: To describe the procedural steps and discuss the mechanical advantages of the novel technique called SAIF-Rod and present the results of our initial case series. Methods: After vertebral body stent expansion within the index vertebra, augmentable screws from the same set as the posterior fixation are introduced via K-wire exchange into the stent lumen. Kyphoplasty augmentation is performed through these screws. A posterior fixation performed above and below the index vertebra is connected to the screws at the index level. Rod-bending and compression maneuvers are used to address residual deformity that could not be corrected through the SAIF alone. Results: A total of 21 patients (13 men) with a mean age of 76 years (interquartile range [IQR] 65-80) and with neoplastic (19%), traumatic (10%), and osteoporotic (71%) thoracolumbar fractures were treated with SAIF-Rod at our institution. Demographic and surgical data for a minimum follow-up of 12 months were presented. No major early or delayed complications (Clavien-Dindo grades 4 or 5) occurred. Mean intraoperative blood loss (150 mL, IQR 100-400), operating time (318 minutes, IQR 263-346), and length of stay at the hospital (7 days, IQR 5-11) were recorded. Conclusion: In selected cases, SAIF-Rod represents a minimally invasive surgical alternative for the treatment of highgrade osteoporotic, traumatic, and neoplastic fractures, usually accompanied by deformity. Level of Evidence: 4.

Introduction:Recurrent lumbar disc herniation (RLDH) is defined as the reappearance, following initial discectomy, of disc material and pain after a period of at least six symptom-free months. Redo surgery is usually considered following unsuccessful conservative management or in the presence of neurological deficits. Research question:Given the lack of consensus on the ideal surgical strategy for RLDH, we conducted this study to evaluate when lumbar fusion (LF) should be considered in the treatment of RLDH. Material and methods:A literature search was conducted on PubMed, Google Scholar and clinicaltrials.gov focusing on the treatment of recurrent disc herniation using microdiscectomy alone or through fusion. The quality of the studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale and Cochrane Risk of Bias Tool 2.0. The weighted mean difference was calculated for both binary and continuous outcomes. Results:This resulted in a list of 900 references, from which 11 studies were identified as meeting the inclusion criteria for the study. There were four prospective studies and seven retrospective studies. A comparison of LF and redo discectomy (RD) revealed no significant differences in clinical outcome scores. LF resulted in significantly higher intraoperative blood loss, longer hospitalizations and longer surgeries. No further differences were identified. Discussion and conclusions:Both LF and RD represent safe and effective treatment options in first RLDH. The choice of surgical strategy should integrate the eventual co-existence of clinical and radiological features of segmental instability, as well subjective aspects, such as surgeons' training and patient preference.

Background: The atlanto-axial segment is highly mobile and, therefore, prone to instability in the setting of inflammatory disease, infection, tumor or trauma. While minimally invasive surgical (MIS) techniques have gained acceptance in the thoracolumbar spine due to their advantages over traditional approaches, their use at the atlanto-axial segment is controversial due to the surgical risk associated with its complex anatomy. To evaluate the current evidence on MIS atlanto-axial fixation, we carried out a systematic review of the literature and compared the reported results with those of open procedures. Methods: This systematic review follows PRISMA-DTA 2020 guidelines. A comprehensive search was conducted in November 2023 across PubMed/Medline, Google Scholar and clinicaltrials.gov using specific keywords related to minimally invasive atlanto-axial fixation. Data regarding study characteristics, patient demographics, surgical techniques, and outcomes were extracted from included studies. Results: This systematic review included 13 articles reporting on the results of surgery in 305 patients, in whom a total of 683 screws were inserted through a posterior MIS approach. N = 162 screws were inserted using the Harms–Goel technique, while N = 521 were placed using the Magerl technique. N = 40 screws were inserted using navigation guidance, while N = 643 were introduced with fluoroscopy assistance. Eight screws were misplaced. A Vertebral Artery (VA) injury was reported in three patients. With a mean value of 26.2 ± 15.3 months, the rate of fusion ranged between 80% and 100%. Conclusions: This study highlights the potential of MIS for posterior atlanto-axial fixation, which was achieved using Magerl transarticular screws in a large majority of cases. Despite technical challenges, MIS approaches appear to achieve satisfactory clinical and radiological outcomes with complication rates similar to those of open techniques. Future studies may help refine the indications for MIS and identify those cases better suited for open approaches.

Background/Objectives: The potential advantages of robotic assistance in spinal procedures are a growing area of interest, and patient perception plays a key role in its broader acceptance. However, public perception of robotic surgery in spinal operations remains unexplored. This study aims to assess the general public’s perceptions, expectations, and concerns regarding robot-assisted spine surgery. Methods: In the fall of 2024, a questionnaire was distributed to attendees at a public open day at the Neurocenter of Southern Switzerland, where the Globus ExcelsiusGPS™ spine surgery robot was demonstrated live on a mannequin. The 15-item questionnaire assessed demographic data, prior knowledge of medical robots, mental representations of surgical robots, expectations, and emotions after witnessing the demonstration. Data were analyzed using descriptive statistics, chi-square, Wilcoxon, McNemar tests, and logistic regression analysis. Results: A total of 109 questionnaires were collected. Most participants were female (64.4%) and had no direct experience with spinal pathology (79.8%). While 87.2% were aware of robotic surgery in general, only 65.1% specifically knew about its use in spine surgery. After witnessing the live demonstration, 81.9% felt reassured by the robot′s presence in surgery, compared to 61.3% before the demonstration (p = 0.007). Preference for robot-assisted surgery increased from 50.5% to 64.5% (p < 0.001). Notably, individuals with back-related issues showed greater confidence in the robot’s capabilities (p = 0.032). Conclusions: The general public perceives robotic spine surgery positively, viewing it as faster, more precise, and capable of performing tasks not readily performed by humans. The study highlights the importance of live demonstrations in enhancing trust and acceptance of robotic systems. Its findings have economic implications, as patients may be more likely to choose hospitals offering robot-assisted spine surgery. However, it is essential to also acknowledge alternative methods, such as computer-assisted navigation, which has demonstrated efficacy in spine surgery.

PURPOSE:The OF5 type of vertebral osteoporotic fracture (AO Spine-DGOU classification) represents a three-column lesion and as such is considered as highly unstable. These lesions, however, tend to affect elderly, frail patients, in whom invasive management options are limited. The stent-screw-assisted internal fixation (SAIF) technique has previously been reported as a minimally invasive treatment for osteoporotic and neoplastic vertebral fractures. Here, we sought to assess the safety and efficacy of the SAIF technique in a retrospective series of patients with thoracic OF5-fractures. METHODS:Retrospective identification, in a prospectively maintained database, of patients with OF5-fractures treated with SAIF. Intra- and post-operative complications were reported. Clinical outcome using NRS pain scale and Patient's Global Impression of Change (PGIC) and radiological outcome, with local kyphotic angle (LKA) and VB height (VBH) correction were analyzed. RESULTS:N = 22 consecutive patients were identified. All fractures were located in the thoracic spine. No intra-procedural complications occurred, although hospitalization-related complications did occur in 2 patients (9 %). There was a statistically significant pain reduction on follow-up. VBH restoration range was 0-12 mm (mean 5.5 mm). The mean postoperative LKA correction was 7.5°, which was maintained at last follow-up. CONCLUSION:The SAIF technique appears to be a viable alternative in the management of OF5-fractures. Although it does not address all elements of OF5 instability, it appears that the stabilisation of the anterior and middle vertebral columns, coupled with the stabilising effect of the ribcage in the hypomobile thoracic spine, are biomechanically sufficient to treat OF5-fractures in this section of the spine.

BACKGROUND AND PURPOSE:Midline sacral meningeal cysts (MSMCs) are cerebrospinal fluid-filled dural diverticula. Although widely considered asymptomatic, cases involving voiding difficulties or pain have been reported. The aims of this study were, firstly, to describe the clinical presentation of patients with symptomatic MSMCs, secondly, to assess the impact of the cyst on nerve root function, and, thirdly, to assess whether nerve root injury is more frequent in patients with MSMCs than those with Tarlov cysts (TCs). METHODS:Consecutive patients with MSMCs presenting with at least one pelvic symptom participated in a cross-sectional review of symptoms using validated questionnaires. Findings of pelvic neurophysiology (pudendal sensory evoked potentials, sacral dermatomal sensory evoked potentials, external anal sphincter electromyography) and urodynamic testing were collected retrospectively. The relationship between neurophysiology, magnetic resonance imaging findings and patients' symptoms were assessed using Fisher's and analysis of variance tests. Neurophysiology findings were compared with those of TC patients. RESULTS:Eleven female patients were included (mean age 42.3 ± 12.4 years). All reported urinary symptoms. Back pain (91%), radicular leg pain (91%), bowel symptoms (45%) and sexual dysfunction (75%) were also frequently reported. Nine patients (82%) had abnormal findings on neurophysiology; three patients (27%) had one abnormal test, and six (55%) had two abnormal tests. Patients with MSMCs were more likely to have at least two abnormal neurophysiology test results compared to TC patients (55% vs. 18%, respectively; p = 0.018). CONCLUSION:Our results indicate that MSMCs are indeed associated with injury to the sacral somatic innervation when symptomatic. MSMCs are more likely to cause sacral nerve root damage compared to TCs.

The cranio-vertebral junction (CVJ) was formerly considered a surgical “no man’s land” due to its complex anatomical and biomechanical features. Surgical approaches and hardware instrumentation have had to be tailored in order to achieve successful outcomes. Nowadays, thanks to the ongoing development of new technologies and surgical techniques, CVJ surgery has come to be widely performed in many spine centers. Accordingly, there is a drive to explore novel solutions and technological nuances that make CVJ surgery safer, faster, and more precise. Improved outcome in CVJ surgery has been achieved thanks to increased safety allowing for reduction in complication rates. The Authors present the latest technological advancements in CVJ surgery in terms of imaging, biomaterials, navigation, robotics, customized implants, 3D-printed technology, video-assisted approaches and neuromonitoring.

Objective: Among the already difficult management of neuro-oncological patients, the elderly population remains vulnerable. Because of the pathology and the comorbidities, they present a significantly higher rate of medical issues related to surgical management. Despite this, the surgical option, if feasible, remains the gold standard in these patients, and an Enhanced Recovery After Surgery (ERAS) protocol could improve the postoperative safety of the patients. With this purpose, we prepared this study with the aim of defining the postoperative hospital length of stay (LOS), but also of evaluating the postoperative morbidity, perioperative complications, and postoperative pain scores. Methods: This was a retrospective, single-cohort study performed at an academic hospital (Department of Neurosurgery, Neurocenter of South Switzerland, Switzerland) on elderly patients who underwent craniotomy for glioblastoma. Patients were enrolled in a novel ERAS protocol from January 2022 to December 2022. Since this is a feasibility study and a direct comparison was not possible, we used a historical cohort of elderly patients who had undergone elective craniotomy surgery for glioblastoma as a control group. Results: A total of 19 patients treated in our center for glioblastoma multiforme (GBM) who were aged over 75 years were included in this study. Among those, seven were newly recruited patients included in the ERAS protocol, while the remaining twelve were part of a historical cohort of previously treated patients. From a statistical point of view, the two cohorts were comparable in terms of baseline demographics. In the follow-up, it was shown that in the ERAS group, there was a reduction in the use of opioids after the surgical procedures that could be seen at 30 days (36.2% vs. 71.7%, p < 0.001), but also at 3 months, after surgery (33.0% vs. 80.0%, p < 0.001). A significant difference has also been documented in terms of mobilization and ambulation: compared to the historical cohort, in the ERAS group, there was a higher rate of mobilization (60.0% vs. 10.0%, p < 0.001), but also of ambulation (36.1% vs. 10.0%, p < 0.001). Conclusions: The ERAS protocol for the management of glioblastoma in elderly patients seems to be an effective option for reducing LOS in the hospital, as well as for reducing the number of days spent in the ICU, improving the general recovery of the patient, and reducing the costs associated with hospitalization.

An extracranial-to-intracranial (EC-IC) bypass is performed to achieve cerebral revascularisation. The main indications for EC-IC bypass are: (i) flow augmentation such as in Moyamoya disease or in other select instances of cerebrovascular occlusive disease, and (ii) flow replacement such as when an intracranial artery is sacrificed in the management of complex cerebrovascular pathology or skull base tumours. 1 Vilela M.D. Newell D.W. Superficial temporal artery to middle cerebral artery bypass: past, present, and future. Neurosurg Focus. 2008; 24: E2 Crossref PubMed Scopus (61) Google Scholar , 2 Raper D.M.S. Rutledge W.C. Winkler E.A. et al. Controversies and advances in adult intracranial bypass surgery in 2020. Oper Neurosurg. 2020; 20 (Hagerstown): 1-7 Crossref Scopus (10) Google Scholar , 3 Yasargil M.G. Yonekawa Y. Results of microsurgical extra-intracranial arterial bypass in the treatment of cerebral ischemia. Neurosurgery. 1977; 1: 22-24 Crossref PubMed Scopus (136) Google Scholar The most common of EC-IC bypass procedures involves anastomosing a branch of the superficial temporal artery (STA) to a branch of the middle cerebral artery (MCA) via a craniotomy to bypass the internal carotid artery and restore blood flow to the brain. This procedure requires neuro-microsurgical expertise. Here, we highlight the technical considerations in a joint Neuro-plastics approach for EC-IC bypass in our centre.

Purpose Pituitary adenomas affect patients' quality-of-life (QoL) across several domains, with long-term implications even following gross-total resection or disease remission. While clinical outcomes can assess treatment efficacy, they do not capture variations in QoL. We present the development and validation of a patient reported outcome measure (PROM) for patients with pituitary adenomas undergoing transsphenoidal surgery. Methods The COSMIN checklist informed the development of the pituitary outcome score (POS). Consecutive patients undergoing surgical treatment for suspected pituitary adenoma at a single centre were included prospectively. An expert focus group and patient interviews informed item generation. Item reduction was conducted through exploratory factor analysis and expert consensus, followed by assessment of the tool's validity, reliability, responsiveness, and interpretability. Results 96 patients with a median age of 50 years validated the POS. The final questionnaire included 25 questions with four subscales: EQ-5D-5L-QoL, Visual Symptoms, Endocrine Symptoms and Nasal Symptoms. Conclusion The POS is the first validated PROM for patients undergoing transsphenoidal surgery for a pituitary adenoma. This PROM could be integrated into contemporary practice to provide patient-centred outcomes assessment for this patient group, aligning more closely with patient objectives.

BACKGROUND: CRANIAL (CSF Rhinorrhoea After Endo nasal Intervention to the Skull Base) is a prospective multicenter observational study seeking to determine 1) the scope of skull base repair methods used and 2) corresponding rates of postoperative cerebrospinal fluid (CSF) rhinorrhea in the endonasal transsphenoidal approach (TSA) and the expanded endonasal approach (EEA) for skull base tumors. We sought to pilot the project, assessing the feasibility and acceptability by gathering preliminary data. METHODS: A prospective observational cohort study was piloted at 12 tertiary neurosurgical units in the United Kingdom. Feedback regarding project positives and challenges were qualitatively analyzed. RESULTS: A total of 187 cases were included: 159 TSA (85%) and 28 EEA (15%). The most common diseases included pituitary adenomas (n = 142/187), craniopharyngiomas (n = 13/187). and skull base meningiomas (n = 4/187). The most common skull base repair techniques used were tissue glues (n = 132/187, most commonly Tisseel), grafts (n = 94/187, most commonly fat autograft or Spongostan) and vascularized flaps (n = 51/187, most commonly nasoseptal). These repairs were most frequently supported by nasal packs (n = 125/187) and lumbar drains (n = 20/187). Biochemically confirmed CSF rhinorrhea occurred in 6/159 patients undergoing TSA (3.8%) and 2/28 patients undergoing EEA (7.1%). Four patients undergoing TSA (2.5%) and 2 patients undergoing EEA (7.1%) required operative management for CSF rhinorrhea (CSF diversion or direct repair). Qualitative feedback was largely positive (themes included user-friendly and efficient data collection and strong support from senior team members), demonstrating acceptability. CONCLUSIONS: Our pilot experience highlights the acceptability and feasibility of CRANIAL. There is a precedent for multicenter dissemination of this project, to establish a benchmark of contemporary practice in skull base neurosurgery, particularly with respect to patients u ndergoing EEA.

-BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, concerns have been raised regarding the increased risk of perioperative mortality for patients with COVID-19, and the transmission risk to healthcare workers, especially during endonasal neurosurgical operations. The Pituitary Society has produced recom-mendations to guide management during this era. We sought to assess contemporary neurosurgical practice and the effects of COVID-19. -METHODS: A multicenter prospective observational cohort study was conducted at 12 tertiary neurosurgical -nits (United Kingdom and Ireland). Data were collected from March 23 to July 31, 2020, inclusive. The data points collected included patient demographics, preoperative COVID-19 test results, operative modifications, and 30-day COVID-19 infection rates. -RESULTS: A total of 124 patients were included. Of the 124 patients, 116 (94%) had undergone COVID-19 testing preoperatively (transsphenoidal approach, 97 of 105 [92%]; expanded endoscopic endonasal approach, 19 of 19 [100%]). One patient (1 of 116 [0.9%]) had tested positive for COVID-19 preoperatively, requiring a delay in surgery until the infection had been confirmed as resolved. Other than transient diabetes insipidus, no other complications were reported for this patient. All operating room staff had worn at least level 2 personal protective equipment. Adapta-tions to surgical techniques included minimizing drilling, draping modifications, and the use of a nasal iodine wash. At 30 days postoperatively, no evidence of COVID-19 infection (symptoms or positive formal testing results) were found in our cohort and no mortality had occurred. -CONCLUSIONS: Preoperative screening protocols and operative modifications have facilitated endonasal neuro-surgery during the COVID-19 pandemic, with the Pituitary Society guidelines followed for most of these operations. We found no evidence of COVID-19 infection in our cohort and no mortality, supporting the use of risk mitigation strategies to continue endonasal neurosurgery in subse-quent pandemic waves.

Objective The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement. Methods We performed a single-center retrospective analysis of accuracy of bolt EVD placement between 1st December 2018 and 31st May 2020, comparing the accuracy outcomes between three levels of training (junior trainees (JT); mid-grade trainees (MT); senior trainees/fellows (ST)). Accuracy was determined radiologically by two methods: Kakarla grade and by measuring the distance of the catheter tip to its optimal position (DTOP) at the foramen of Monro. Results Eighty-seven patients underwent insertion of bolt EVDs, of which n = 19 by JT, n = 40 by MT and n = 28 by ST, with a significant difference found between training grades in the median Kakarla grade (p = 0.0055) and in the accuracy of placement as per DTOP (p = 0.0168). Conclusions In contrast to previous published results on tunneled EVDs, we demonstrate that the accuracy of bolt EVD placement is dependent on neurosurgical experience. Our results draw awareness to the fact that the bolt EVD technique can represent a challenge for less experienced practitioners and underline the importance of dedicated training to support the safe insertion of bolt ventricular catheters.

Background The endonasal transsphenoidal approach (TSA) has emerged as the preferred approach in order to treat pituitary adenoma and related sellar pathologies. The recently adopted expanded endonasal approach (EEA) has improved access to the ventral skull base whilst retaining the principles of minimally invasive surgery. Despite the advantages these approaches offer, cerebrospinal fluid (CSF) rhinorrhoea remains a common complication. There is currently a lack of comparative evidence to guide the best choice of skull base reconstruction, resulting in considerable heterogeneity of current practice. This study aims to determine: (1) the scope of the methods of skull base repair; and (2) the corresponding rates of postoperative CSF rhinorrhoea in contemporary neurosurgical practice in the UK and Ireland. Methods We will adopt a multicentre, prospective, observational cohort design. All neurosurgical units in the UK and Ireland performing the relevant surgeries (TSA and EEA) will be eligible to participate. Eligible cases will be prospectively recruited over 6 months with 6 months of postoperative follow-up. Data points collected will include: demographics, tumour characteristics, operative data), and postoperative outcomes. Primary outcomes include skull base repair technique and CSF rhinorrhoea (biochemically confirmed and/or requiring intervention) rates. Pooled data will be analysed using descriptive statistics. All skull base repair methods used and CSF leak rates for TSA and EEA will be compared against rates listed in the literature. Ethics and dissemination Formal institutional ethical board review was not required owing to the nature of the study - this was confirmed with the Health Research Authority, UK. Conclusions The need for this multicentre, prospective, observational study is highlighted by the relative paucity of literature and the resultant lack of consensus on the topic. It is hoped that the results will give insight into contemporary practice in the UK and Ireland and will inform future studies.

BACKGROUND:Symptomatic midline sacral meningeal cysts (MSMC) are rare, and, as a consequence, so are reports on the surgical techniques to address these lesions. Here we provide a description of the senior author's (ATC) technique.METHOD:A sacral laminectomy is performed. The cyst's relation with the dural sac and sacral nerves is inspected; it is then opened and drained. Its lumen is explored for its point of communication with the dural sac, and this ostium is closed off with non-penetrating clips. A lumbar drain is inserted in select cases.CONCLUSION:Cyst wall resection is unnecessary and closing the ostium is sufficient to treat MSMC.

Background Transsphenoidal surgery is the gold standard for pituitary adenoma resection. Although rare, a serious complication of surgery is worsened vision post-operatively. Objective To determine whether, in patients undergoing transsphenoidal surgery for pituitary adenoma, intraoperative monitoring of visual evoked potentials (VEP) is a safe, reproducible, and effective technological adjunct in predicting postoperative visual function. Methods The PubMed and OVID platforms were searched between January 1993 and December 2020 to identify publications that (1) featured patients undergoing transsphenoidal surgery for pituitary adenoma, (2) used intraoperative optic nerve monitoring with VEP and (3) reported on safety or effectiveness. Reference lists were cross-checked and expert opinion sought to identify further publications. Results Eleven studies were included comprising ten case series and one prospective cohort study. All employed techniques to improve reliability. No safety issues were reported. The only comparative study included described a statistically significant improvement in post-operative visual field testing when VEP monitoring was used. The remaining case-series varied in conclusion. In nine studies, surgical manipulation was halted in the event of a VEP amplitude decrease suggesting a widespread consensus that this is a warning sign of injury to the anterior optic apparatus. Conclusions Despite limited and low-quality published evidence regarding intra-operative VEP monitoring, our review suggests that it is a safe, reproducible, and increasingly effective technique of predicting postoperative visual deficits. Further studies specific to transsphenoidal surgery are required to determine its utility in protecting visual function in the resection of complex pituitary tumours.

Background. Ultrasound has been explored as an alternative, less bulky, less time-consuming and less expensive means of intraoperative imaging in pituitary surgery. However, its use has been limited by the size of its probes relative to the transsphenoidal corridor. We developed a novel prototype that is more slender than previously reported forward-viewing probes and, in this report, we assess its feasibility and safety in an initial patient cohort. Method. The probe was integrated into the transsphenoidal approach in patients with pituitary adenoma, following a single-centre prospective proof of concept study design, as defined by the Innovation, Development, Exploration, Assessment and Long-Term Study (IDEAL) guidelines for assessing innovation in surgery (IDEAL stage 1 - Idea phase). Results. The probe was employed in 5 cases, and its ability to be used alongside the standard surgical equipment was demonstrated in each case. No adverse events were encountered. The average surgical time was 20 minutes longer than that of 30 contemporaneous cases operated without intraoperative ultrasound. Conclusion. We demonstrate the safety and feasibility of our novel ultrasound probe during transsphenoidal procedures to the pituitary fossa, and, as a next step, plan to integrate the device into a surgical navigation system (IDEAL Stage 2a - Development phase).

Background The endoscopic endonasal approach for optic nerve decompression is suited for the management of non-traumatic optic neuropathy but remains underreported, presumably due to transcranial approaches still being favoured at individual centres. Method The optic canal is approached endoscopically and transsphenoidally through the contralateral nostril. Its inferomedial wall is opened using an irrigated diamond drill, and neuronavigation is used to confirm anatomical bearings. Conclusion This technique provides rapid and easy access to the inferomedial aspect of the optic canal and nerve. Optic nerve decompression through this approach is associated with low morbidity and should be considered as an alternative to transcranial approaches.