Scratching in the minefield: using intertriangles line to safely perform anterior petrosectomy

PURPOSE

The transpetrosal-transtentorial approach provides a practical and safe surgical corridor for the treatment of petroclival region lesions. Any inaccuracies while performing this surgical technique can result in catastrophic results; nevertheless, this can be prevented under the guidance of a detailed anatomical orientation. An "intertriangles line" was defined to preserve the internal auditory canal (IAC) and cochlea during extradural bone drilling.

METHODS

The anatomical study consisted of two groups: the cadaveric head and the skull group. A literature-based landmark and criteria list was created to examine the borders of the Kawase triangle/space and evaluate the anatomical structures that may be at risk during drilling for anterior petrosectomy.

RESULTS

A total of 20 cadaveric head sides and 30 dried skull sides were examined. The rhomboid area was divided into two triangles with a common the intertriangles line. In all dissections, the IAC was found to be localized posterior to the "intertriangle line". A minimum distance of 1 mm for the Internal Carotid artery and 2 mm for the IAC can serve as threshold values to be considered by the surgeon during drilling for petrosectomy.

CONCLUSIONS

Kawase's area resembles a minefield, in which every step and manipulation should be considered. A minimal but effective resection of the cranial base is needed to increase safety and decrease morbidity during skull base surgery. Furthermore, this study investigated accessible and prominent landmarks to establish a feasible area of triangles and define the intertriangles line to guide the neurosurgeon under microscope and avoid IAC injury.

Macrovascular Decompression for Hemifacial Spasm Using Sling Technique

Hemifacial spasm (HFS) is a painless, involuntary twitching of the facial muscles that usually involves the orbicularis oculi muscle.1,2 It is commonly caused by the anterior inferior cerebellar artery or posterior inferior cerebellar artery.1,2 However, a dolichoectatic vertebrobasilar artery (VBA) can impinge the facial nerve.1 Macrovascular decompression with sling transposition is a common management paradigm.1-9 We present a case of a 56-year-old male who presented with left-sided HFS, pulsatile tinnitus, and hearing loss for the past 2 years. The patient underwent a retrosigmoid craniotomy and Gore-Tex sling transposition of a dolichoectatic VBA (Video 1). Complete improvement of symptoms was noted postoperatively with no associated complications. We review the preoperative workup, operative technique, relevant anatomy, and literature and provide technical pearls for this procedure.

[Anterior transpetrosal (Kawase) approach for petroclival meningioma with trigeminal neuralgia: case report and literature review]

The authors present a patient with petroclival meningioma complicated by trigeminal neuralgia. Resection of tumor via anterior transpetrosal approach with microvascular decompression of the trigeminal nerve was performed. A 48-year-old female patient presented with left-sided (V1-V2) trigeminal neuralgia. Magnetic resonance imaging revealed a tumor 33´27´25 mm with a base adjacent to the top of petrous part of the left temporal bone, tentorium cerebelli and clivus. Intraoperative examination revealed true petroclival meningioma extending to trigeminal notch of petrous part of temporal bone. There was additional compression of trigeminal nerve by caudal branch of superior cerebellar artery. Total resection of tumor was followed by disappearance of vascular compression of trigeminal nerve and regression of trigeminal neuralgia. Anterior transpetrosal approach provides early devascularization and resection of true petroclival meningioma, as well as wide imaging of anterolateral surface of the brainstem, identification of neurovascular conflict and vascular decompression.

Anterior transpetrosal approach for microvascular decompression associated with the dolichoectatic vertebrobasilar artery in two patients with refractory trigeminal neuralgia: Technical note

Background

Trigeminal neuralgia (TN) due to compression from the dolichoectatic vertebrobasilar artery (DVBA) is extremely rare and difficult to treat due to its morphological characteristics. We report two cases of good transposition of DVBA and postoperative course obtained using the anterior petrosal approach and a new vasoculopexy method.

Methods

We describe two cases of microvascular decompression (MVD) for refractory TN associated with DVBA. In both cases, MVD was performed through the anterior petrosal approach. The DVBA was decompressed using a GORE-TEX sling and WECK clip in an inferomedial direction.

Results

Complete pain relief without new neurological deterioration was achieved immediately in both patients.

Conclusion

We experienced a rare condition of TN due to exclusion by the DVBA. The anterior transpetrosal approach was extremely effective in this case. This approach secured the surgical field, allowed transposition of the DVBA, and caused no perioperative complications.

Macrovascular Decompression with the Transposition Method Using Teflon Sling for Trigeminal Neuralgia Caused by the Vertebrobasilar Artery

OBJECTIVE

Complete separation of the vertebrobasilar artery (VBA) from the trigeminal nerve by microvascular decompression is technically challenging. This paper evaluates the transposition method using Teflon sling for trigeminal neuralgia (TN) caused by the VBA.

METHODS

Retrospective review of 32 patients including 2 patients with tic convulsif. Mobilization of the VBA in the anteromedial-caudal direction and repositioning of the VBA using Teflon sling and fibrin glue were performed. Pre- and postoperative pain were evaluated with the Barrow Neurological Institute (BNI) pain intensity score. Duration of surgery and postoperative neurologic complications were reviewed.

RESULTS

Preoperative BNI score ranged from III to V. Postoperative BNI score I was observed in 30 patients, II in 1 patient, and V in 1 patient as recurrence. Abducens nerve palsy was observed in 9 patients but was transient in 8. Permanent hearing loss was observed in 6 patients. Transient mild lower cranial nerve palsy was recorded in 2 patients with tic convulsif. Average surgical time was 290 minutes.

CONCLUSIONS

Our method for trigeminal neuralgia caused by VBA was very effective, but the complication rate of cranial nerve disorders was also high. A high rate of complications implied the technical difficulty of extensive vascular mobilization requiring long duration of surgery. Macrovascular decompression surgery is more descriptive of this surgery instead of microvascular decompression surgery.

The "Binder Ring" Bypass: Transection, Rerouting, and Reanastomosis as an Alternative to Macrovascular Decompression of a Dolichoectatic Vertebral Artery

BACKGROUND

In cases of extreme vertebrobasilar dolichoectasia, padding the cranial nerves (CNs) (microvascular decompression [MVD]) and clip-assisted sling transposition of the tortuous artery (macrovascular decompression [MaVD]) may be ineffective because the sling does not reduce the redundancy. Transposition may not decompress the nerves or may kink the artery. An alternative solution is needed.

OBJECTIVE

To introduce the "binder ring" bypass as a novel solution to this unusual macrovascular compression problem.

METHODS

The binder ring denotes the opening and closing of the offending vascular loop with standard bypass techniques with the artery transected, rerouted lateral to the CNs, and reanastomosed. An example case study is presented for a 72-year-old man whose severe vertebral artery tortuosity could not be relieved by MVD or MaVD. His pathology was exposed with an extended retrosigmoid craniotomy, the V4 segment was transected, the free ends were mobilized lateral to CN VII/VIII, and an end-to-end reanastomosis was performed with intraluminal suturing.

RESULTS

The example binder ring bypass was patent angiographically, and the patient experienced immediate and lasting symptom relief without complications.

CONCLUSION

The binder ring bypass applies standard bypass techniques to macrovascular compression but represents a significant escalation in technical challenges relative to traditional techniques. Patient tolerance to temporary arterial occlusion during reanastomosis depends on the location of the compressive arterial loop and the anatomy of collateral circulation. The binder ring bypass should be used as a last resort after medical therapy and MaVD techniques fail and performed only by neurosurgeons with advanced bypass skills.

Macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach in a patient suffering from trigeminal neuralgia – A case report

Introduction

Secondary trigeminal neuralgia due to vertebrobasilar dolichoectasia is a rare entity. Surgical therapy via pterional craniotomy approach and anterior petrosectomy has already been described in literature. We present an 81-year female patient suffering from left sided trigeminal neuralgia due to vertebrobasilar dolichoectasia.

Research question

We show in this case report a macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach.

Material and methods

Successful decompression under continuous intraoperative neuromonitoring via pure Kawase approach and ventro-lateral transposition of a dolichoectatic vertebral artery through a polyester-titanium sling was achieved.

Results

Postoperative the patient described an immediate improvement of the trigeminal neuralgia symptoms. At the two-month postoperative follow-up the patient remained trigeminal neuralgia painless free and suffered from a regredient facial nerve palsy.

Discussion and conclusion

We report for the first time a successful macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach under continuous intraoperative neuromonitoring. In-contrast to traditional suboccipital retrosigmoidal approach our strategy obtains sufficient working space and angles. Thus, adequate transposition of the dolichoectatic vessel could be achieved.

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Secondary trigeminal neuralgia due to vertebrobasilar dolichoectasia is a rare entity.

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Successful macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach.

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Transposition through a polyester-titanium sling.

Melittin-loaded Iron Oxide Nanoparticles Prevent Intracranial Arterial Dolichoectasia Development through Inhibition of Macrophage-mediated Inflammation

Rationale: In intracranial arterial dolichoectasia (IADE) development, the feedback loop between inflammatory cytokines and macrophages involves TNF-α and NF-κB signaling pathways and leads to subsequent MMP-9 activation and extracellular matrix (ECM) degeneration. In this proof-of-concept study, melittin-loaded L-arginine-coated iron oxide nanoparticle (MeLioN) was proposed as the protective measure of IADE formation for this macrophage-mediated inflammation and ECM degeneration.

Methods: IADE was created in 8-week-old C57BL/6J male mice by inducing hypertension and elastase injection into a basal cistern. Melittin was loaded on the surface of ION as a core-shell structure (hydrodynamic size, 202.4 nm; polydispersity index, 0.158). Treatment of MeLioN (2.5 mg/kg, five doses) started after the IADE induction, and the brain was harvested in the third week. In the healthy control, disease control, and MeLioN-treated group, the morphologic changes of the cerebral arterial wall were measured by diameter, thickness, and ECM composition. The expression level of MMP-9, CD68, MCP-1, TNF-α, and NF-κB was assessed from immunohistochemistry, polymerase chain reaction, and Western blot assay.

Results: MeLioN prevented morphologic changes of cerebral arterial wall related to IADE formation by restoring ECM alterations and suppressing MMP-9 expression. MeLioN inhibited MCP-1 expression and reduced CD68-positive macrophage recruitments into cerebral arterial walls. MeLioN blocked TNF-α activation and NF-κB signaling pathway. In the Sylvian cistern, co-localization was found between the CD68-positive macrophage infiltrations and the MeLioN distributions detected on Prussian Blue and T2* gradient-echo MRI, suggesting the role of macrophage harboring MeLioN.

Conclusions: The macrophage infiltration into the arterial wall plays a critical role in the MMP-9 secretion. MeLioN, designed for ION-mediated melittin delivery, effectively prevents IADE formation by suppressing macrophage-mediated inflammations and MMP activity. MeLioN can be a promising strategy preventing IADE development in high-risk populations.

Petroclival Meningioma Leading to Trigeminal Neuralgia: A Kawase Approach Application

BACKGROUND

Trigeminal neuralgia is defined by paroxysmal pain on the trigeminal nerve territory. The petroclival meningioma presents with trigeminal neuralgia in less than 5% of the cases. We report a case of a petroclival meningioma that encased the fifth nerve and was resected through a Kawase approach.

CLINICAL PRESENTATION

A 67-year-old female patient presented paroxysmal shock pain in malar and ocular region with progressive worsening, evolving with daily crises despite the use of carbamazepine. On neurologic examination the patient was oriented, with no strength or coordination impairments. Cranial nerves exam showed left V1, V2, and V3 thermal and pain hypoesthesia, without allodynia. Normal strength in masticatory muscles was observed. Magnetic resonance imaging revealed a petroclival lesion with hypersign on T2 and contrast enhancement, suggestive of a meningioma. The tumor encased the trigeminal nerve at the entrance of the Meckel's cave. A temporal craniotomy with middle fossa peeling and anterior petrosectomy (Kawase approach) was performed and a Simpson II resection was achieved. The patient evolved with transient sixth nerve palsy, recovering completely after 3 months. During a follow-up of 5 years there was no evidence of tumor recurrence and the patient is free from pain without medication.

CONCLUSIONS

The Kawase approach is an interesting access for petroclival tumor resection.

[Microvascular decompression in trigeminal neuralgia following vertebrobasilar dolichoectasia]

OBJECTIVE

To analyze our own results with literature data and substantiate microvascular decompression in patients with trigeminal neuralgia (TN) following vertebrobasilar dolichoectasia (VBD).

MATERIAL AND METHODS

A total of 504 patients with TN underwent surgery in 1998-2018. Patients with TN following VBD were included into a retrospective study. There were 4 men and 10 women aged 66 years (range 51-80). Outcomes were evaluated using BNI (Barrow Neurological Institute) scale. PubMed database was used for literature review.

RESULTS

TN caused by VBD was diagnosed in 2.8% of patients. Left-sided trigeminal pain was observed in 10 patients, right-sided - in 4 cases. One patient had concomitant hemifacial spasm. MVD followed by shielding of trigeminal nerve root with shredded Teflon was performed in all patients. We did not perform fixation of vertebrobasilar vessels. In one case, open partial trigeminal nerve root rhizotomy was done in addition to MVD. All patients had pain-free early postoperative period. There were no deaths or major complications. There was transient cranial nerve dysfunction lasting no more than three months (facial numbness - 1, IV nerve dysfunction - 1, VI nerve dysfunction - 1, transient partial facial palsy (House-Brackmann II) - 2, hipoacusia - 2 patients). There was no facial pain recurrence in our group. Mean follow-up period was 5.5 years (range 6 months - 16 years).

CONCLUSION

MVD is an effective option in the treatment of TN following VBD. In these cases, operation is technically more difficult compared to MVD with intact vessels. However, surgery is much more effective than all the available alternatives. The possibilities of vessel transposition in VBD with or without fixation are limited and ineffective. Teflon wool interposition at the points of conflict is an effective and sufficient technique.

Transposition of Vessels for Microvascular Decompression of Posterior Fossa Cranial Nerves: Review of Literature and Intraoperative Decision-Making Scheme

INTRODUCTION

Microvascular decompression with transposition of the involved vessels provides good surgical outcomes in cases of complex and recurrent neurovascular compression syndromes. We conducted a literature review to illustrate the variations in the surgical techniques used for transposition and to provide a practical decision-making scheme for transposition of the involved vessel.

METHODS

A PubMed Medline database record search was conducted using the following algorithm ("Microvascular Decompression Surgery"[Mesh]) OR (((Microvascular) OR (Macrovascular)) AND decompression AND surgery) AND (transposition). Only articles that detailed the intraoperative techniques were included.

RESULTS

A total of 48 articles were included. The adjacent anatomical walls to which the compressing vessel can be anchored were divided into 4 groups; A: roof (tentorium cerebelli), B: anterior wall (posterior surface of petrous bone and clivus), C: posterior wall (petrosal surface of the cerebellum), and D: "no wall" required. A new decision-making scheme based on the following 2 questions was designed: 1) is the conflicting vessel amenable to transposition to a nearby wall in the cerebello-brainstem space? 2) what is the closest wall to secure the transposed vessel?

CONCLUSIONS

Transposition of the involved vessel is a valuable procedure for microvascular decompression of the posterior fossa cranial nerves. Anchoring the vessel to the adjacent anatomical wall ensures secure transposition. The proposed algorithm provides a systemic scheme to identify the optimal anatomical wall, and to determine the technique and material that can be used to anchor involved vessel. This scheme is an efficient method to inform the intraoperative decision-making process.