Exploring optimal microscopic keyhole access to the skull base: an anatomical evaluation of transciliary supraorbital and transpalpebral orbitofrontal craniotomy approaches.

PURPOSE: The past two decades have witnessed the rise of keyhole microscopic minimally invasive surgeries, including the transciliary supraorbital approach (TCA) and transpalpebral approach (TPA), commonly known as the transorbital approach. This study aims to elucidate the nuances, specific indications, and advantages of each approach. METHODS: A series of dissections were conducted on five formalin-fixed, alcohol-preserved cadaver heads. The TCA was performed on one side, and the TPA on the other. Virtual measurements of working angles for both approaches were recorded. Additionally, three clinical cases were presented to illustrate the practical application of the techniques. RESULTS: For TCA, the craniotomy dimensions were 1.7 cm x 2.5 cm (Cranial-Caudal (CC) x Lateral-Lateral (LL)), while for TPA, they measured 2.1 cm x 2.9 cm (CC x LL). The measurements of anterior clinoid processes (ACP) were obtained and compared between approaches. In the TCA, the mean ipsilateral ACP measurement was 62 mm (Range: 61 -63 mm), and the mean contralateral ACP measurement was 71.2 mm (Range: 70 -72 mm). In TPA, these measurements were 47.8 mm (Range: 47 -49 mm) and 62.8 mm (Range: 62 -64 mm), respectively. TCA exhibited an average cranial-caudal angle of 14.9°, while TPA demonstrated an average of 8.3°. CONCLUSION: The anterior cranial fossa was better exposed by a TCA, which also featured shorter operative times, enhanced midline visualization, and a quicker learning curve. Conversely, the middle fossa was better exposed by a TPA, making it an excellent option for middle fossa pathologies, including those in the anterior temporal lobe. After sphenoid bone wing drilling, the TPA offers superior visualization from the lateral to the medial aspect and enhances the CC angle. Additionally, the TPA reduces the risk of postoperative frontalis palsy based on anatomic landmarks. However, the TPA requires a greater cranial osteotomy, and due to unfamiliarity with eyelid anatomy, the learning curve for most neurosurgeons is lengthier for this procedure.

Frontotemporal Orbitozygomatic Transcavernous Approach: Stepwise Cadaveric Dissection for a Safe Corridor.

Background Advances in skull base surgery have increased the need for a detailed understanding of skull base anatomy and its intrinsic relationship to surrounding structures. This has resulted in an improvement in patient outcomes. The frontotemporal orbitozygomatic (FTOZ) transcavernous approach (TCA) is an excellent option for treating complex lesions involving multiple compartments of the skull base, including the sellar and parasellar, third ventricle, orbit, and petroclival region. Objective This article aimed to provide a detailed cadaveric dissection accompanying a thorough procedure description, including some tips and pitfalls of this technique. Methods Microsurgical dissection was performed in four freshly injected cadaver heads at the Cranial Base Neuroanatomy Laboratory, Cleveland Clinic Florida. The FTOZ TCA was performed on both sides of the four specimens. The advantages and disadvantages were discussed based on the anatomic nuances of this approach. Results The FTOZ TCA represented a wide access to the anterior, middle, and posterior fossa. When combined with an anterior clinoidectomy, it allowed for significant and safe internal carotid artery mobilization. This approach created numerous windows, including opticocarotid, carotid-oculomotor, supratrochlear, infratrochlear, anteromedial, anterolateral, and posteromedial triangles. The only drawback was the length of the dissection and the level of surgical acumen required to perform it. Conclusion Despite its technical difficulty, the FTOZ TCA should be considered for the surgical management of basilar apex aneurysms and tumors surrounding the cavernous sinus, sellar/parasellar, retrochiasmatic, and petroclival region. Continuous training and dedicated time in the skull base laboratory can help achieve the necessary skills required to perform this approach.

Trigeminal Neuralgia-Step-by-Step DYNA-Computed Tomography-Assisted Balloon Compression Rhizotomy.

Trigeminal nerve balloon compression (TNBC)1-3 can provide immediate therapeutic relief to patients suffering from trigeminal neuralgia. This is a particularly effective treatment option for patients who are not eligible for surgical procedures (i.e., elderly patients or patients with multiple comorbidities) or for patients who have had an insufficient response to microvascular decompression. TNBC can also be used as a bridge treatment before stereotactic radiosurgery. Use of intraoperative computed tomography-like images using a C-arm system (DYNA-CT) imaging facilitates the TNBC procedure.4,5 Three-dimensional DYNA-CT imaging with needle guidance allows for precise needle advancement and insertion through the foramen ovale. DYNA-CT enables the direct visualization and avoidance of vascular structures such as the carotid or internal maxillary arteries and results in decreased procedure times and complications. The authors present a step-by-step video demonstrating the use of intraoperative DYNA-CT needle guidance for TNBC (Video 1). A Siemens Artis Zee Biplane system is used for the procedure. A comprehensive description of all elements of the procedure is provided including balloon preparation, needle trajectory planning, needle advancement, 3-dimensional confirmation of the needle's depth and path, balloon placement, balloon inflation, and balloon removal. Tips and optimal strategies are presented. Advantages of using DYNA-CT for needle guidance include the reduction of fluoroscopy dose and fluoroscopy time. The average dose area product during conventional percutaneous balloon compression in prior studies was 1137 mGycm2, with a mean fluoroscopic time of 62 seconds.6 In our experience, the mean fluoroscopy dose is 274 mGycm2 and the total fluoroscopic time is about 45 seconds. Furthermore, during the DYNA-CT acquisition, the neurointerventional team stays outside the room during the DYNA-CT, which reduces the cumulative radiation to the operator. DYNA-CT needle guidance facilitates precise advancement of the needle into the foramen ovale and positioning of the balloon in the Meckel cave during TNBC. It is a safe and feasible technique that allows for the visualization and avoidance of important structures such as the internal carotid artery or the internal maxillary artery, resulting in decreased procedure times and complications.

Anatomical Description and Literature Review of the Endoscopic Endonasal Transclival Transodontoid Approach Combined with Endoscopic Transoral Decompression to the Anterior Craniovertebral Junction: A New Strategy.

OBJECTIVE: To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction. METHODS: The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported. RESULTS: Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation. CONCLUSIONS: Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory.

Enhanced recovery after surgery in patients with normal pressure hydrocephalus undergoing ventriculoperitoneal shunting procedures.

OBJECTIVE: Patients with idiopathic normal pressure hydrocephalus (iNPH) who undergo ventriculoperitoneal shunt (VPS) placement often belong to an older demographic, putting them at increased risk of postoperative delirium and related complications. Recent literature documenting the use of Enhanced Recovery After Surgery (ERAS) protocols in various disciplines of surgery has shown improved clinical outcomes, faster discharge, and lower readmission rates. Early return to a familiar environment (i.e., discharged home) is a well-known predictor of reduced postoperative delirium. However, ERAS protocols are uncommon in neurosurgery, especially intracranial procedures. We developed a novel ERAS protocol for patients with iNPH undergoing VPS placement to gain further insight regarding postoperative complications, specifically delirium. METHODS: We studied 40 patients with iNPH with indications for VPS. Seventeen patients were selected at random to undergo the ERAS protocol, and twenty-three patients underwent the standard VPS protocol. The ERAS protocol consisted of measures to reduce infection, manage pain, minimize invasiveness, confirm procedural success with imaging, and shorten the length of stay. Pre-operative American Society of Anesthesiologists (ASA) grade was collected for each patient to indicate baseline risk. Rates of readmission and postoperative complications, including delirium and infection, were collected at 48 h, 2 weeks, and 4 weeks postoperatively. RESULTS: There were no perioperative complications among the 40 patients. There was no postoperative delirium in any of the ERAS patients. Postoperative delirium was observed in 10 of 23 non-ERAS patients. There was no statistically significant difference between the ASA grade between the ERAS and non-ERAS groups. CONCLUSIONS: We described a novel ERAS protocol for patients with iNPH receiving VPS focusing on an early discharge. Our data suggest that ERAS protocols in VPS patients might reduce the incidence of delirium without increasing the risk of infection or other postoperative complications.

Endoscopic endonasal optic nerve sheath decompression (EONSD) for idiopathic intracranial hypertension: Technical details and meta-analysis.

BACKGROUND: The neurosurgical management of idiopathic intracranial hypertension (IIH) remains controversial. Although shunting and newer endovascular stenting techniques are part of the neurosurgical armamentarium to treat medically refractory IIH symptoms, optic nerve sheath fenestration has traditionally been performed by ophthalmologists. OBJECTIVE: We present a detailed cadaveric dissection that simulates the endoscopic endonasal optic nerve sheath decompression (EONSD) technique along with the literature review. METHODS: EONSD was performed in four freshly injected cadaveric specimens. Additionally, a systematic review from different electronic databases has been done. RESULTS: Bilateral EONSD was performed in all specimens without significant technical difficulties. Based on our experience, there is no need to expose the periorbita or orbital apex. The primary anatomic landmarks were the optic canal, the lateral opticocarotid recess, the tuberculum, the limbus, and the clinoid segment of the internal carotid artery. Based on the systematic review, 68 patients (77.9% female) underwent EONSD, with a mean age of 33.4 ± 6.9 years in adult patients. Follow-up ranged from 3 to 58 months across different studies. The pooled meta-analysis showed headache, papilledema, and visual disturbance improvement in 78% [95%CI 0.65-0.90], 72% [95%CI 0.61-0.83], and 88% [95%CI 0.80-0.96] of cases who underwent EONSD, respectively. The subgroup analysis showed there was no statistically significant difference between unilateral and bilateral EONSD in terms of different measured outcomes. CONCLUSION: EONSD is a feasible surgical procedure that may obviate the need for shunting in patients with IIH. Although clinical studies showed that EONSD is a safe and effective technique, further studies are required to establish the preferences of either unilateral or bilateral approaches.