Tag: oculomotor nerve

Posted on

The oculomotor cistern and pituitary adenomas: anatomical and clinical study

J Neurosurg 142:766–776, 2025

• Study Focus: The research investigates the oculomotor cistern (OMC) and its involvement with pituitary adenomas (PitNETs), aiming to provide a histomorphological description and analyze its clinical impact.

• Methods: Ten hemisellae from formalin-fixed specimens were studied, and clinical data from patients undergoing endoscopic transsphenoidal surgery for PitNETs between 2014 and 2021 were analyzed.

• Results: OMC involvement was graded as not compressed, compressed, and invaded. Significant associations were found between OMC involvement and PitNET dimensions, Knosp grade, and preoperative oculomotor palsy.

• OMC Shape and Measurements: The OMC is elliptical with an average area of 3.1 mm² and a length of 5.5 mm. No points of weakness were identified in the histomorphological study.

• Clinical Findings: OMC compression and invasion were recorded in 43.1% and 9.3% of patients, respectively. Preoperative CN III palsy was documented in compressed (11.3%) and invasive (26.1%) OMCs.

• Surgical Implications: Endoscopic transsphenoidal surgery is effective in treating PitNETs with OMC involvement, though the choice between transcranial and endoscopic approaches remains debated.

• Histological Observations: The study confirmed the OMC’s extension ends before the anterior clinoid process (ACP), with potential points of weakness at the CS roof and MWCS.

• Conclusion: OMC involvement is significant in PitNETs, affecting patient outcomes. Detailed preoperative evaluation and postoperative follow-up are crucial for managing these cases.

Posted on

Hakuba’s triangle: a cadaveric study detailing its anatomy and neurovascular contents with vascular and skull base implications

Neurosurgical Review (2022) 45:2087–2093

Hakuba’s triangle is a superior cavernous sinus triangle that allows for wide and relatively safe exposure of vascular and neoplastic lesions.

This study provides cadaveric measurements of the borders of Hakuba’s triangle and describes its neurovascular contents in order to enrich the available literature.

The anatomical borders of the Hakuba’s triangle (lateral, medial, and posterior borders) were defined based on Hakuba’s description and identified. Then the triangle was dissected to reveal its morphology and relationship with adjacent neurovascular structures in Embalmed Caucasian cadaveric specimens.

The oculomotor nerve occupied roughly one-third of the area of the triangle and the nerve was more or less parallel to its medial border. The mean lengths of the lateral border, posterior border, and medial border were 17 mm ± 0.5 mm, 12.2 mm ± 0.4 mm, and 10.6 mm ± 0.4 mm, respectively. The mean area of Hakuba’s triangle was 63.9 mm 2 ± 4.4 mm 2 .

In this study, we provided cadaveric measurements of the borders of Hakuba’s triangle along with descriptions of its neurovascular contents.

Posted on

A clinical study of ocular motor nerve functions after petroclival meningioma resection

Acta Neurochirurgica (2020) 162:1249–1257

Ocular motor dysfunction is one of the most common postoperative complications of petroclival meningioma. However, its incidence, recovery rate, and independent risk factors remain poorly explored.

Methods: A prospective analysis of 31 petroclival meningiomas was performed. Operative approaches were selected by utilizing a new 6-region classification of petroclival meningiomas we proposed. Two scores were used to evaluate the functions of the oculomotor and abducens nerves. Pearson correlation analysis and binary logistic regression analysis were used to identify independent risk factors for intraoperative oculomotor and abducens nerve injury.

Results: Postoperative new-onset dysfunctions in the pupillary light reflex and eye/eyelid movements as well as abducens paralysis were detected in eight (25.8%), ten (32.3%) and twelve (38.7%) cases, respectively. Their corresponding recovery rates after 6 months of follow-up were 75% (6/8), 80% (8/10), and 83.3% (10/12), respectively, and their mean times to start recovery were 4.03, 2.43, and 2.5 months, respectively. Tumor invasion into the suprasellar region/sphenoid sinus was the only risk factor for dysfunctions in both the pupillary light reflex (p = 0.001) and eye/ eyelid movements (p = 0.002). Intraoperative utilization of the infratrigeminal interspace was the only risk factor for dysfunction in eyeball abduction movement (p = 0.004).

Conclusions: Dysfunctions of the oculomotor and abducens nerves recovered within 6 months postoperatively. Tumor extension into the suprasellar region/sphenoid sinus was the only risk factor for oculomotor nerve paralysis. Eye/eyelid movements were more sensitive than the pupillary light reflex in reflecting nerve dysfunctions. Intraoperative utilization of the infratrigeminal interspace was the only risk factor for abducens nerve paralysis.

Posted on

Recovery from oculomotor nerve palsy due to posterior communicating artery aneurysms: results after clipping versus coiling in a single-center series

Recovery from oculomotor nerve palsy due to posterior communicating artery aneurysms- results after clipping versus coiling in a single-center series

Acta Neurochir (2014) 156:879–884

Oculomotor nerve palsy (ONP) is a common clinical manifestation of ruptured or unruptured posterior communicating artery (PcomA) aneurysms. Although microsurgical clip ligation has been proven a safe and durable treatment, endovascular management is emerging as an increasingly popular alternative. The aim of our study is to compare the recovery rate from ONP and assess the safety and long-term durability of both techniques.

Methods We have reviewed the retrospective data concerning twenty-two patients treated at our institution between 2004 and 2012 for PcomA aneurysms with ONP. Seven patients were operated on via a standard pterional approach, and fourteen were treated by endovascular occlusion with coils. One patient was managed conservatively. Pre-treatment and post-treatment severity of ONP was recorded, as well as the duration of symptoms before admission and treatment-related complications.

Results All seven patients who underwent surgery improved, with six total recoveries and one partial recovery. Among the fourteen patients treated by embolization, thirteen initially recovered, but long-term follow-up revealed three cases of exacerbation of ONP after refilling of the aneurysms. Two of them were clipped, and one embolized. Also, one partially resolved patient underwent a second embolization. No severe complications occurred in either group.

Conclusions Despite the small number of patients, our study suggests that both surgical clipping and embolization are safe and effective methods in regards to functional recovery (complete ONP recovery in about 85 % of the cases). However, coiling may lead to delayed recurrence of third cranial nerve (CN) palsy at long-term follow-up, requiring additional treatment. Keywords

Posted on

Extended Subtemporal Transtentorial Approach to the Anterior Incisural Space and Upper Clival Region: Experience With Posterior Circulation Aneurysms

Extended Subtemporal Transtentorial Approach to the Anterior Incisural Space and Upper Clival Region- Experience With Posterior Circulation Aneurysms

Neurosurgery 10:15–24, 2014

Although most posterior circulation aneurysms are currently treated by endovascular means, some are not amenable to this treatment modality. The narrow working window afforded by the anterolateral and lateral surgical approaches often translates into suboptimal visualization and limited maneuverability.

OBJECTIVE: We present a modified technique of tentorial incision and reflection that optimizes the exposure achieved with the traditional subtemporal approach and report our clinical experience in a series of posterior circulation aneurysms.

METHODS: Retrospective review of patients operated via an extended subtemporal transtentorial approach for posterior circulation aneurysms. The modified tentorial incision implies dissection of the trochlear nerve along its dural canal up to its entrance into the cavernous sinus and incision of a tentorial flap that extends up to Meckel cave, which is then reflected far anterolaterally. Clinical and radiological data were reviewed.

RESULTS: This series comprises 18 patients (21 procedures). Ten patients presented (56%) with a subarachnoid hemorrhage. Aneurysms most frequently arose from the basilar tip (61%) and were of small size (50%) and saccular morphology (72%). Two patients underwent surgery following unsuccessful endovascular treatment. Aneurysm treatment was successful on the first attempt in 90% (19/21) and after a second attempt in 10% (2/21). Documented postoperative palsies of the oculomotor (n = 3) and trochlear (n = 1) nerves were all transient. No procedure-related mortality occurred.

CONCLUSION: This modified technique of tentorial incision and reflection optimizes visibility, anatomic orientation, and maneuverability by increasing the rostrocaudal and anterolateral exposure obtained via the extended subtemporal transtentorial route without permanent postoperative trochlear nerve deficit.

Posted on

Safety of drilling for clinoidectomy and optic canal unroofing in anterior skull base surgery

Clinoidectomy and optic canal unroofing

Acta Neurochir (2013) 155:1017–1024

Skull base drilling is a necessary and important element of skull base surgery; however, drilling around vulnerable neurovascular structures has certain risks. We aimed to assess the frequency of complications related to drilling the anterior skull base in the area of the optic nerve (ON) and internal carotid artery (ICA), in a large series of patients.

Methods We included anterior skull base surgeries performed from 2000 to 2012 that demanded unroofing of the optic canal, with extra- or intradural clinoidectomy and/or drilling of the clinoidal process and lateral aspect of the tuberculum sella. Data was retrieved from a prospective database and supplementary retrospective file review. Our IRB waived the requirement for informed consent. The nature and location of pathology, clinical presentation, surgical techniques, surgical morbidity and mortality, pre- and postoperative vision, and neurological outcomes were reviewed.

Results There were 205 surgeries, including 22 procedures with bilateral optic canal unroofing (227 optic canals unroofed). There was no mortality, drilling-related vascular damage, or brain trauma. Complications possibly related to drilling included CSF leak (6 patients, 2.9 %), new ipsilateral blindness (3 patients, 1.5 %), visual deterioration (3 patients, 1.5 %), and transient oculomotor palsy (5 patients, 2.4 %). In all patients with new neuropathies, the optic and oculomotor nerves were manipulated during tumor removal; thus, new deficits could have resulted from drilling, or tumor dissection, or both.

Conclusion Drilling of the clinoid process and tuberculum sella, and optic canal unroofing are important surgical techniques, which may be performed relatively safely by a skilled neurosurgeon.

Posted on

Superciliary keyhole surgery for unruptured posterior communicating artery aneurysms with oculomotor nerve palsy: maximizing symptomatic resolution and minimizing surgical invasiveness

Journal of Neurosurgery Oct 2011 / Vol. 115 / No. 4 / Pages 700-706

For oculomotor nerve palsy (ONP) induced by unruptured posterior communicating artery (PCoA) aneurysms, the authors performed surgical clipping via a superciliary keyhole approach as an optimal treatment modality with high efficiency and low invasiveness. In this study, they then evaluated the technical feasibility, safety, clinical outcomes, including recovery from ONP as well as cosmetic results, and durability of the procedure.

METHODS Thirteen patients presenting with complete (7 patients) or incomplete (6 patients) ONP underwent surgery via a superciliary approach. The operative video record was used to evaluate the technical feasibility, neurological examinations and CT were performed to analyze the safety of the treatment, and neuroophthalmological examinations and 3D CT angiography were undertaken to determine the effectiveness and durability of the treatment.

RESULTS In all cases, the aneurysms were successfully clipped using a 3.5-cm eyebrow incision and supraorbital minicraniotomy. The mean operative time was 108 ± 24 minutes. Twelve (92.3%) of the 13 patients showed complete resolution of the ONP. All 6 patients (100%) with incomplete ONP recovered completely within 1–2 months after surgery, whereas 6 (85.7%) of the 7 patients with complete ONP recovered completely within 1–6 months after surgery. Cosmetic results for the operative wounds were excellent without frontalis palsy. The durability of the treatment was ascertained based on 3D CT angiograms obtained 1 year after surgery.

CONCLUSIONS Surgical clipping via a superciliary keyhole approach can be an optimal treatment modality for PCoA aneurysms inducing ONP because it is effective, safe, and durable.

Proudly powered by WordPress