Pilot Validation of a 3-Dimensional Printed Pituitary Adenoma, Vascular Injury, and Cerebrospinal Fluid Leak Surgical Simulator.

BACKGROUND AND OBJECTIVES: Endoscopic skull base surgery is a subspecialty field which would benefit significantly from high-fidelity surgical simulators. Giving trainees the opportunity to flatten their learning curve by practicing a variety of procedures on surgical simulators will inevitably improve patient outcomes. METHODS: Four neurosurgeons, 8 otolarynologists, and 6 expert course faculty agreed to participate. All participants were asked to perform a transsphenoidal exposure and resection of a pituitary adenoma, repair a cerebrospinal fluid (CSF) leak, control a carotid injury, and repair a skull base defect. The content, face, and construct validity of the 3-dimensional printed model was examined. RESULTS: The heart rate of the participants significantly increased from baseline when starting the carotid injury simulation (mean 90 vs 121, P = .029) and significantly decreased once the injury was controlled (mean 121 vs 110, P = .033, respectively). The participants reported a significant improvement in anxiety in facing a major vascular injury, as well as an increase in their confidence in management of major vascular injury, resecting a pituitary adenoma and repair of a CSF leak using a 5-point Likert scale (mean 4.42 vs 3.58 P = .05, 2 vs 3.25 P < .001, 2.36 vs 4.27 P < .001 and 2.45 vs 4.0 P = .001, respectively). The mean Objective Structured Assessment of Technical Skills score for experienced stations was 4.4, significantly higher than the Objective Structured Assessment of Technical Skills score for inexperienced stations (mean 3.65, P = .016). CONCLUSION: We have demonstrated for the first time a validated 3-dimensional printed surgical simulator for endoscopic pituitary surgery that allows surgeons to practice a transsphenoidal approach, surgical resection of a pituitary adenoma, repair of a CSF leak in the diaphragma sellae, control of a carotid injury, and repair of skull base defect.

Neuronavigation in endoscopic skull base surgery and the accuracy of different MRI sequences.

OBJECTIVE: Neuronavigation is common technology used by skull base teams when performing endoscopic endonasal surgery. A common practice of MRI imagining is to obtain 3D isotopic gadolinium enhanced T1W magnetisation prepared rapid gradient echo (MPRAGE) sequences. These are prone to distortion when undertaken on 3 T magnets. The aim of this project is to compare the in vivo accuracy of MRI sequences between current and new high resolution 3D sequences. The goal is to determine if geometric distortion significantly affects neuronavigation accuracy. METHODS: Patients were scanned with a 3D T1 MPRAGE sequence, 3D T1 SPACE sequence and a CT stereotactic localisation. Following general anaesthesia, patients were registered on the Stealth Station (Medtronic, USA) using a side mount emitter for Electromagnetic navigation. A variety of surgically relevant anatomical landmarks in the sagittal and coronal plane were selected with real and virtual data points measured. RESULTS: A total of 10 patients agreed be enrolled in the study with datapoints collected during surgery. The distance between real and virtual datapoints trended to be lower in SPACE sequences compared to MPRAGE. Paired t test did not demonstrate a significant difference. CONCLUSION: We have demonstrated that navigational accuracy is not significantly affected by the type of MRI sequence selected and that current corrective algorithms are sufficient. Navigational accuracy is affected by many factors, with registration error likely playing the most significant role. Further research involving real time imaging such as endoscopic ultrasound may hopefully address this potential error.

Management of frontoethmoidal osteoma causing pneumocephalus and cerebrospinal fluid leakage with minimally invasive techniques: illustrative cases.

BACKGROUND: Osteoid osteoma is a common benign bone tumor frequently seen in the frontoethmoid region. However, involvement of the skull base is rare, with few cases previously reported. OBSERVATIONS: The authors report two cases of spontaneous, symptomatic frontoethmoidal osteoma: one presented with neurological deficit secondary to tension pneumocephalus and the other with cerebrospinal fluid leakage. The first case was managed with a transfrontal sinus craniotomy and pneumocephalus decompression with osteoma resection and skull base reconstruction. The second case was managed with a uninaral endoscopic endonasal approach to the anterior skull base with osteoma resection and reconstruction. LESSONS: Given the paucity of cases with associated tension pneumocephalus described in the literature, it was relevant to describe the authors' experience with surgical decision-making and the expected outcomes among patients with this pathology when using minimally invasive techniques.

'What's in a name', a systematic review of the pterional craniotomy for aneurysm surgery and its many modifications with a proposal for simplified nomenclature.

BACKGROUND: The pterional or frontosphenotemporal craniotomy has stood the test of time and continues to be a commonly used method of managing a variety of neurosurgical pathology. Already described in the beginning of the twentieth century and perfected by Yasargil in the 1970s, it has seen many modifications. These modifications have been a normal evolution for most neurosurgeons, tailoring the craniotomy to the patients' specific anatomy and pathology. Nonetheless, an abundance of variations have appeared in the literature. METHODS: A search strategy was devised according to the 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. To identify articles investigating the variations in the pterional approach, the following search terms were applied: (pterional OR minipterional OR supraorbital) AND (approach OR craniotomy OR technique). RESULTS: In total, 3552 articles were screened with 74 articles being read in full with 47 articles being included for review. Each article was examined according the name of the technique, temporalis dissection technique, craniotomy technique and approach. CONCLUSION: This systematic review gives an overview of the different techniques and modifications to the pterional craniotomy since it was initially described. We advocate for the use of a more standardised nomenclature that focuses on the target zone to simplify the management approach to supratentorial aneurysms.

The Learning Curve for Endoscopic Endonasal Transsphenoidal Pituitary Surgery: Evaluating Endocrine Outcomes.

OBJECTIVE: In South Australia endoscopic endonasal approach (EEA) pituitary surgery has been practiced since 2006, largely by two neurosurgeons with a small fellowship-trained otolaryngology team. The aim of this cohort study was to determine if a "learning curve" can be established over this time period, as represented by structural and endocrine patient outcomes. METHOD: Retrospective cohort study of patients undergoing EEA surgery between 2006 and 2021 in Adelaide, South Australia at three tertiary teaching hospitals.. Cases were divided by each surgeon and split into groups of sequential 40 cases. Endocrine assessment pre- and post-operatively involved static pituitary and end-organ hormones, with dynamic tests as required, assessed by an pituitary endocrinologist. Each hormonal axis (gonadal, cortisol, thyroid, prolactin and growth hormone) was documented preoperatively and at an early and long term follow up at 1-2 and 12 months, respectively. RESULTS: The study included a cohort of 443 pituitary adenomas managed with endoscopic endonasal transsphenoidal surgery in a consecutive fashion between two neurosurgeons over 16-years. Gross tumour resection but not visual visual outcomes improved with surgical experience but this outcome may be neurosurgeon dependent. Endocrine outcomes were not consistently improved with experience, but lower rates of hypopituitarism were seen with experience with one neurosurgeon. Average follow up was approximately 5 years, and a minimum follow up of 12 months for all patients. CONCLUSIONS: We present long term endocrine follow up for patients with functional and non-functional adenomas. Improved rates of gross tumour resection were evident with with surgical experience. However, there was no apparent change in post-operative endocrine outcomes.

The learning curve for endoscopic endonasal pituitary surgery: a systematic review.

Recent literature demonstrates that a learning curve exists for endoscopic pituitary surgery. However, there is significant variability in the way these studies report their outcomes. This study aims to systematically review the literature regarding outcomes for endoscopic pituitary surgery and how this may be related to a surgical learning curve. An electronic search of the databases Medline, Scopus, Embase, Web of Science and Cochrane Library databases was performed and data extracted according 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. Ten articles were included in the review as they examined the following: rates of gross total resection, average operative time, CSF leak rate, visual outcomes, endocrine outcomes and how these results were influenced by surgical experience. We have demonstrated that a learning curve exists for some outcome variables for endoscopic pituitary surgery. However, there is significant heterogeneity in the current body of literature which makes clear comparisons difficult.

Olfaction preservation in olfactory groove meningiomas: a systematic review.

Olfactory groove meningiomas (OGM) are a skull base neoplasm that represents between 8 and 13% of all intracranial meningiomas. Approach selection focuses on achieving frontal lobe decompression, gross total resection and vision preservation. Recently, there has been a focus on olfaction and considering its preservation as a quality-of-life outcome measure. An electronic search of the databases Medline, Scopus, Embase, Web of Science and Cochrane library databases was performed and data extracted according 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. Six articles were selected for inclusion mainly based due to reporting quantitative outcomes for olfaction assessed by a smell identification test (e.g. sniffin' sticks). Objective olfaction preservation can be achieved with a variety of surgical approaches. More research which includes objective assessment of olfactory function and ideally as well QoL outcome measures is needed to further optimize the treatment pathways in OGM patients.

Stereoscopic Three-Dimensional Neuroanatomy Lectures Enhance Neurosurgical Training: Prospective Comparison with Traditional Teaching.

OBJECTIVE: Stereoscopic three-dimensional (3D) imaging is increasingly used in the teaching of neuroanatomy and although this is mainly aimed at undergraduate medical students, it has enormous potential for enhancing the training of neurosurgeons. This study aims to assess whether 3D lecturing is an effective method of enhancing the knowledge and confidence of neurosurgeons and how it compares with traditional two-dimensional (2D) lecturing and cadaveric training. METHODS: Three separate teaching sessions for neurosurgical trainees were organized: 1) 2D course (2D lecture + cadaveric session), 2) 3D lecture alone, and 3) 3D course (3D lecture + cadaveric session). Before and after each session, delegates were asked to complete questionnaires containing questions relating to surgical experience, anatomic knowledge, confidence in performing procedures, and perceived value of 3D, 2D, and cadaveric teaching. RESULTS: Although both 2D and 3D lectures and courses were similarly effective at improving self-rated knowledge and understanding, the 3D lecture and course were associated with significantly greater gains in confidence reported by the delegates for performing a subfrontal approach and sylvian fissure dissection. CONCLUSIONS: Stereoscopic 3D lectures provide neurosurgical trainees with greater confidence for performing standard operative approaches and enhances the benefit of subsequent practical experience in developing technical skills in cadaveric dissection.