Comparative Analysis of Surgical Exposure among Endoscopic Endonasal Approaches to Petrosectomy: An Experimental Study in Cadavers

Objectives Endoscopic endonasal approaches (EEAs) for petrosectomies are evolving to reduce perioperative brain injuries and complications. Surgical terminology, techniques, landmarks, advantages, and limitations of these approaches remain ill defined. We quantitatively analyzed the anatomical relationships and differences between EEA exposures for medial, inferior, and inferomedial petrosectomies. Design This study presents anatomical dissection and quantitative analysis. Setting Cadaveric heads were used for dissection. EEAs were performed using the medial petrosectomy (MP), the inferior petrosectomy (IP), and the inferomedial petrosectomy (IMP) techniques. Participants Six cadaver heads (12 sides, total) were dissected; each technique was performed on four sides. Main Outcomes and Measures Outcomes included the area of exposure, visible distances, angles of attack, and bone resection volume. Results The IMP technique provided a greater area of exposure (p < 0.01) and bone resection volume (p < 0.01) when compared with the MP and IP techniques. The IMP technique had a longer working length of the abducens nerve (cranial nerve [CN] VI) than the MP technique (p < 0.01). The IMP technique demonstrated higher angles of attack to specific neurovascular structures when compared with the MP (midpons [p = 0.04], anterior inferior cerebellar artery [p < 0.01], proximal part of the cisternal CN VI segment [p = 0.02]) and IP (flocculus [p = 0.02] and the proximal [p = 0.02] and distal parts [p = 0.02] of the CN VII/VIII complex) techniques. Conclusion Each of these approaches offers varying degrees of access to the petroclival region, and the surgical approach should be appropriately tailored to the pathology. Overall, the IMP technique provides greater EEA surgical exposure to vital neurovascular structures than the MP and the IP techniques.

Recurrent Isolated Sixth Nerve Palsy in Childhood—Review on a Rare Phenomenon

Sixth nerve palsy is an ominous sign in pediatric neurology. Due to the long and tortuous course of the sixth (abducens) nerve, it is generally considered a sign of intracranial pathology. Sixth nerve palsy is associated with increased intracranial pressure and neoplasms, among other less frequent causes. In ∼5 to 15% of cases, no cause can be identified. These cases are classified as idiopathic or “benign” and recovery is typically complete. A recurrence of symptoms is very rare. We provide a rare case report of recurrent benign sixth nerve palsy in a 5-year-old child. In addition, we provide an overview of all earlier published cases of recurrent isolated sixth nerve palsy. To date, only 72 pediatric patients with recurrent isolated sixth nerve palsy have been reported. Young females with left-sided sixth nerve palsy and recent immunization are at risk of recurrence. Pathophysiological mechanisms have been discussed, but have yet to be clarified. Recurrent isolated sixth nerve palsy is only rarely associated with severe causes and the need for extensive investigation may be questioned.

Cavernous sinus dural arteriovenous fistula accessed through a straightened superficial temporal vein

Background: Transvenous embolization through the inferior petrosal sinus (IPS) is the most common treatment procedure for cavernous sinus dural arteriovenous fistula (CSDAVF). When the IPS is inaccessible or the CSDAVF cannot be treated with transvenous embolization through the IPS, the superficial temporal vein (STV) is used as an alternative access route. However, the approach through the STV is often challenging because of its tortuous and abruptly angulated course. We report a case of recurrent CSDAVF which was successfully treated using a chronic total occlusion (CTO)-dedicated guidewire and by straightening the STV. Case Description: A 63-year-old woman was diagnosed with CSDAVF on examination for oculomotor and abducens nerve palsy. She was initially treated with transvenous embolization through the IPS. However, CSDAVF recurred, and transvenous embolization was performed through the STV. A microcatheter could not be navigated because of the highly meandering access route through the STV. By inserting a CTO-dedicated guidewire into the microcatheter, the STV was straightened and the microcatheter could be navigated into a shunted pouch of the CS. Finally, complete occlusion of the CSDAVF was achieved. Conclusion: If an access route is highly meandering, the approach can be facilitated by straightening the access route with a CTO-dedicated guidewire.

Delayed Diplopia After Sports-Related Concussion: A Multidisciplinary Approach to Evaluation and Management

ObjectiveTo highlight a multidisciplinary approach to the diagnosis and management of unilateral abducens palsy after a sports-related concussion.BackgroundMild traumatic brain injury (TBI) often leads to disruptions in visual functioning, affecting convergence, saccades, smooth pursuit, and accommodation. More severe TBI injuries may result in structural injuries to the ocular muscles, nerves, or the brain itself.Design/MethodsNA.ResultsCase: We present the case of a 33-year-old male with unilateral abducens nerve palsy after a sports-related concussion with loss of consciousness and multiple hemorrhagic contusions. The patient's visual symptoms manifested several days after the injury. With a multi-disciplinary evaluation involving specialists representing neurosurgery, endovascular neurology and neuro-ophthamology, unenhanced magnetic resonance imaging revealed multiple foci of intraparenchymal microhemorrhages and siderosis consistent with diffuse axonal injury (DAI), and an incidental parasagittal cavernoma. The delayed development of a sixth nerve palsy raised our suspicion for secondary axotomy, as has been described following TBI. While the probability of recovery is high, close follow up is imperative to address evolution of the patient's symptoms. In this case, the patient developed imbalance and headaches in association with his visual symptoms. For the imbalance we use physical therapy with therapists trained in vestibular therapy and for the visual symptoms we use vision therapy with trained optometrists.ConclusionsDelayed post-traumatic abducens palsy is concerning for DAI and secondary axotomy. Multidisciplinary assessment imparts the ability to evaluate for all possible causes and provide additional specialized care for recovery.

A Rare Case of Dengue Fever with Abducens Nerve Palsy

Dengue fever is one of the most common vector borne disease which is a viral infection transmitted by aedes mosquito. Most common in the tropical countries. Neurological manifestations are not commonly seen in dengue, it can present as encephalitis, encephalopathy, neuromuscular disorders and neuro-ocular disorders. Cranial mononeuropathy is a very exceptional manifestation. A 48-year-old Indian male was diagnosed with dengue, complicated with isolated unilateral sixth cranial nerve palsy. The patient was managed conservatively. Patient made a fast and full ocular recovery following treatment with methyl prednisolone. Hence, dengue can present with a cranial nerve palsy and the recovery process can be hasten with the use of corticosteroids.