The cruciform drain: a technical note on the surgical management of cystic lesions of the sella

Background: The postoperative recurrence of cystic lesions of the sella is frequent and may require further surgery for re-drainage. / Objective: To tackle this problem, we propose to insert a small cross-shaped drain coursing from the cyst lumen to the suprasellar cistern. At this early stage of innovation, the technique is primarily intended for patients who present with a recurrence. / Methods: The cruciform drain is fashioned from the tip of a ventricular catheter and is inserted under endoscopic vision. We retrospectively reviewed the pre- and postoperative records of patients in whom this technique was implemented. / Results: A cruciform drain was placed in five patients since the introduction of the technique into our practice in 2018. The use of the cruciform drain did not impact upon the expected surgical workflow nor was it associated with adverse intraoperative events, but three patients did develop a postoperative CSF leak that was successfully treated in all cases. None of the patients showed re-collection of their cysts on early radiological follow-up. / Conclusion: The cruciform drain is intended to prevent the renewed build-up of cystic fluid by allowing it to flow through and around the drain into the subarachnoid space. We have modified our repair protocol in response to the observed high CSF leak rate, as a basis for further development of the technique. Studies involving long-term follow-up will also be required to assess its efficacy in reducing cyst recurrence

A Novel Intraoperative Ultrasound Probe for Transsphenoidal Surgery: First-in-human study.

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)

Intraoperative monitoring of visual evoked potentials in patients undergoing transsphenoidal surgery for pituitary adenoma: a systematic review

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

Neuronavigation-assisted bedside placement of bolt external ventricular drains in the intensive care setting: a technical note

Background: The insertion of bolt external ventricular drains (EVD) on the intensive care unit (ICU) has enabled rapid cranial cerebrospinal fluid (CSF) diversion. However, bolt EVDs tend to be perceived as a more challenging technique, particularly when dealing with small ventricles or when there is midline shift distorting the ventricular morphology. Furthermore, if neuronavigation guidance is felt to be necessary, this usually assumes a transfer to an operating theatre. In this technical note, we describe the use of electromagnetic neuronavigation for bolt EVD insertion on the ICU and assess the protocol’s feasibility and accuracy. / Methods: Case series of neuronavigation-assisted bolt EVD insertion in ICU setting, using Medtronic Flat Emitter for StealthStation EM. / Results: Neuronavigation-guided bolt EVDs were placed at the bedside in n = 5 patients on ICU. Their widest frontal ventricular horn diameter in the coronal plane ranged from 11 to 20 mm. No procedural complications were encountered. Post-procedural CT confirmed the optimal placement of the EVDs. / Conclusions: Electromagnetic neuronavigation is feasible at the ICU bedside and can assist the insertion of bolt EVDs in this setting. The preference for a bolt EVD to be inserted in ICU—as is standard practice at this unit—should not prohibit patients from benefitting from image guidance if required

Proof of Concept: Wearable Augmented Reality Video See-Through Display for Neuro-Endoscopy

In mini-invasive surgery and in endoscopic procedures, the surgeon operates without a direct visualization of the patient’s anatomy. In image-guided surgery, solutions based on wearable augmented reality (AR) represent the most promising ones. The authors describe the characteristics that an ideal Head Mounted Display (HMD) must have to guarantee safety and accuracy in AR-guided neurosurgical interventions and design the ideal virtual content for guiding crucial task in neuro endoscopic surgery. The selected sequence of AR content to obtain an effective guidance during surgery is tested in a Microsoft Hololens based app

CSF Rhinorrhea After Endonasal Intervention to the Skull Base (CRANIAL) — Part 2:Impact of COVID-19

Background During the pandemic, there has been a concern about the increased risk of perioperative mortality for patients with COVID-19, and the transmission risk to healthcare workers, particularly during endonasal neurosurgical operations. The Pituitary Society produced recommendations to guide management during this era. We sought to assess contemporary neurosurgical practice and the impact of COVID-19. Methods A multicentre, prospective, observational cohort study was conducted at twelve tertiary neurosurgical units (UK and Ireland). Data were collected from March 23rd-July 31st, 2020 inclusive. Data points collected were patient demographics, pre-operative COVID-19 testing, intra-operative operative modifications, and 30-day COVID infection rates. Results 124 patients were included. 116 patients (n=116/124, 94%) underwent COVID-19 testing pre-operatively (TSA: 97/105, 92%; EEA: 19/19, 100%). One patient (n=1/115, 1%) tested positively for COVID-19 pre-operatively, requiring a delay of operation until the infection was confirmed as resolved. Asides from transient diabetes insipidus; no other complications were reported for this case. All theatre staff wore at least level 2 PPE. Adaptations to surgical techniques included minimising drilling, draping modifications, and using nasal iodine wash. At 30 days postoperatively, there was no evidence of COVID infection (symptoms or on formal testing) in our cohort, and no mortality. Conclusions Preoperative screening protocols and operative modifications have facilitated endonasal neurosurgery during the COVID-19 pandemic, with Pituitary Society guidelines followed for the majority of these operations. There was no evidence of COVID infection in our cohort, and no mortality, supporting the use of risk mitigation strategies to continue endonasal neurosurgery in subsequent pandemic waves

CSF Rhinorrhoea After Endonasal Intervention to the Skull Base (CRANIAL) - Part 1: Multicenter Pilot Study

Background: CRANIAL (CSF Rhinorrhoea After Endonasal Intervention to the Skull Base) is a prospective, multicentre observational study seeking to determine: (1) the scope of skull base repair methods used; and (2) corresponding rates of postoperative CSF rhinorrhoea in endonasal transsphenoidal (TSA) expanded endonasal approaches (EEA) for skull base tumours. We sought to pilot the project - assessing the feasibility and acceptability by gathering preliminary data. / Methods: A prospective, observational cohort pilot study was carried out at twelve tertiary UK neurosurgical units. Feedback regarding project positives and challenges were qualitatively analysed. / Results: 187 cases were included, 159 TSA (85%) and 28 EEA (15%). The most common pathologies included: pituitary adenomas (n=141/187), 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 vascularised flaps (n=51/187, most commonly nasoseptal). These repairs were most frequently supported by nasal packs (n=125/187) and lumbar drains (n=22/187). Biochemically-confirmed CSF rhinorrhoea occurred in 6/159 (3.8%) TSA and 2/28 (7.1%) EEA. Four TSA (3%) and two EEA (7%) cases required operative management for CSF rhinorrhoea (CSF diversion or direct repair). Qualitative feedback was largely positive (themes included: user-friendly and efficient data collection, strong support from senior team members) demonstrating acceptability. / Conclusions: Our pilot experience highlights the acceptability and feasibility of CRANIAL. There is a precedent for multicentre dissemination of this project, in order to establish a benchmark of contemporary skull base neurosurgery practice, particularly with respect to EEA cases

CSF Rhinorrhoea After Endonasal Intervention to the Skull Base (CRANIAL) - Part 1:Multicenter Pilot Study

Background CRANIAL (CSF Rhinorrhoea After Endonasal Intervention to the Skull Base) is a prospective, multicentre observational study seeking to determine: (1) the scope of skull base repair methods used; and (2) corresponding rates of postoperative CSF rhinorrhoea in endonasal transsphenoidal (TSA) expanded endonasal approaches (EEA) for skull base tumours. We sought to pilot the project - assessing the feasibility and acceptability by gathering preliminary data. Methods A prospective, observational cohort pilot study was carried out at twelve tertiary UK neurosurgical units. Feedback regarding project positives and challenges were qualitatively analysed. Results 187 cases were included, 159 TSA (85%) and 28 EEA (15%). The most common pathologies included: pituitary adenomas (n=141/187), 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 vascularised flaps (n=51/187, most commonly nasoseptal). These repairs were most frequently supported by nasal packs (n=125/187) and lumbar drains (n=22/187). Biochemically-confirmed CSF rhinorrhoea occurred in 6/159 (3.8%) TSA and 2/28 (7.1%) EEA. Four TSA (3%) and two EEA (7%) cases required operative management for CSF rhinorrhoea (CSF diversion or direct repair). Qualitative feedback was largely positive (themes included: user-friendly and efficient data collection, strong support from senior team members) demonstrating acceptability. Conclusions Our pilot experience highlights the acceptability and feasibility of CRANIAL. There is a precedent for multicentre dissemination of this project, in order to establish a benchmark of contemporary skull base neurosurgery practice, particularly with respect to EEA cases. Keywords Cerebrospinal fluid rhinorrhoeaCSFCerebrospinal fluid leakskull base surgeryendoscopic endonasalEE

Image overlay surgery based on augmented reality : a systematic review

Acknowledgements We thank the staff of the Medical Library of the University of Aberdeen for their advice and Prof. Jennifer Cleland and Dr Jenny Gregory for discussion and support. This work was funded by the Roland Sutton Academic Trust (0053/R/17) and an Elphinstone PhD Scholarship from the University of Aberdeen.Postprin