Telovelar/Transcerebellomedullary Fissure Approach: Giant Distal Posterior Inferior Cerebellar Artery Aneurysm, Epidermoid Cyst, and Brainstem Cavernoma: 2-Dimensional Operative Video

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE

The telovelar or transcerebellomedullary fissure approach can provide wide exposure of the cerebellomedullary fissure and fourth ventricle by separating the natural plane between the medulla and cerebellum. 1-5.

ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT

The cerebellar tonsil is attached to the adjacent cerebellum only by the tonsillar peduncle at its superolateral edge. 2 The posterior inferior cerebellar artery (PICA) runs in the cerebellomedullary fissure, usually making its caudal and cranial loops. 6,7.

ESSENTIALS STEPS OF THE PROCEDURE

After widely opening the foramen magnum, the tonsil is gently elevated by shearing the tela choroidea up to the lateral recess from the taenia, where the vein of the inferior cerebellar peduncle courses. 8,9.

PITFALLS/AVOIDANCE OF COMPLICATIONS

The developed occipital sinus, posterior condylar vein, and anomalies of the vertebral artery and PICA origin can obstruct the exposure. Detailed neuromonitoring is essential for accomplishing the procedure safely. 10,11.

VARIANTS AND INDICATIONS FOR THEIR USE

This exposure can be extended to the lower cerebellopontine angle and can also be applied to the dorsal brainstem surgery. 2,12 The patients consented to the procedure and to the publication of their images.Image Credits: Department of Neurosurgery, Tokyo Medical University logo used by permission. Image at 0:10, 1:02, 2:46, 6:22, and 7:10 from Matsushima and Kohno, 1 used by permission from Medical View Co., Ltd.Right image at 0:14 and also upper image at 0:46, image at 1:26, and for left and lower right images at 1:54 from Matsushima et al, 2 by permission from Journal of Neurosurgery Publishing Group (JNSPG). Left image at 0:14, from Matsushima et al, 4 used by permission from the Congress of Neurological Surgeons. Lower image at 0:46 reprinted from Matsushima et al, 9 by permission from Elsevier. Left image at 1:06 from Matsushima et al, 8 used by permission from the Congress of Neurological Surgeons.Image at top right at 1:54 from Lister et al, 6 used by permission from the Congress of Neurological Surgeons. Image in center at 6:56 from Matsushima et al, 11 used by permission from Springer Nature. Image at right at 6:56 from Matsushima et al, 10 used by permission from JNSPG. Images at 9:48, by year: 1982 article screenshot and figure from Matsushima et al, 4 by permission from the Congress of Neurological Surgeons; 1992: article title screenshot from Matsushima et al, 3 by permission from the Congress of Neurological Surgeons; 1996: used with permission of McGraw-Hill Health Professions Division, from Microsurgical Anatomy of the Fourth Ventrical, Matshushiam T and Rhoton AL Jr, in Neurosurgery , eds Wilkins and Rengachary, vol 1, 1996, permission conveyed through Copyright Clearance Center, Inc.; 2000: article title screenshot from Mussi et al, 5 reused with permission from JNSPG; 2001: article title screenshot from Matsushima, Transcerebellomedullary fissure approach with special reference to methods of dissecting the fissure, J Neurosurg , vol 91, 2001, p. 257-264, by permission from JNSPG; 2021: article title screenshot from Matsushima et al, 12 by permission from Springer Nature. Images at 11:05 from Inoue T et al, "Surgical approach to the mesencephalic vascular malformation" [in Japanese], Surg Cereb Stroke , vol 26, 1998, p 288-289, by permission from the Japanese Society on Surgery for Cerebral Stroke. Cadaveric image at 11:56 from Matsushima T et al, "Exposure of the wide interior of the fourth ventricle without splitting the vermis: importance of cutting procedures for the tela choroidea" Neurosurg Rev , vol 35, 2012, p 563-571, used with permission from Springer Nature.

Comparative analysis of MVD and RHZ in the treatment of primary glossopharyngeal neuralgia: A clinical report on 61 cases

Objective

Clinical data on 61 patients (grouped by their treatment with MVD or RHZ) with glossopharyngeal neuralgia were analyzed retrospectively. A summary analysis of the effective rate and surgical complications of MVD and RHZ in the treatment of glossopharyngeal neuralgia was performed to observe the new surgical options for GN.

Method

From March 2013 to March 2020, 63 patients with GN were admitted to our hospital by the professional group of cranial nerve diseases. Two patients diagnosed with tongue and pharynx pain secondary to tongue cancer and upper esophageal cancer, respectively were excluded from the group. The remaining patients all met the diagnosis of GN, some of them were treated with MVD and others were treated with RHZ. The pain relief rate, long-term results, and complications of the patients in the two groups were well-organized and analyzed.

Result

Of the 61 patients, 39 were treated with MVD and 22 were treated with RHZ. In the early-stage patients (the first 23 patients), all of them were operated on with the MVD procedure except one patient without vascular compression. In the later-stage patients, MVD was performed for evident single arterial compression according to the intraoperative situation. And for compression of arteries with greater tension or PICA + VA complex compression, RHZ was performed. It was also performed in cases where vessels with tight adhesions to the arachnoid and nerves could not be easily separated, or where it was easy to damage the perforating arteries after separating the blood vessels, causing vasospasm, which affects the blood supply to the brainstem and cerebellum. RHZ was also performed if there was no clear vascular compression. The efficiency of both groups was 100%. In the MVD group, one case recurred 4 years after the initial operation, and RHZ was performed for reoperation. Complications related to the operation included one case of swallowing and coughing in the MVD group, and three cases in the RHZ group; two cases of uvula not centering in the MVD group, and five cases in the RHZ group. There was 2 patients in RHZ group lost taste in 2/3 of the backing of the tongue, though these symptoms mostly disappeared or decreased after follow-up. One patient in the RHZ group had developed tachycardia by the time of the long-term follow-up, but whether it was related to the surgery is still uncertain. In terms of serious complications, there were two cases of postoperative bleeding in the MVD group. Based on the clinical characteristics of the patients' bleeding, it was judged that the cause of the bleeding was ischemia and was related to an intraoperative injury to the penetrating artery of the PICA artery and vasospasm.

Conclusion

MVD and RHZ are effective methods for the treatment of primary glossopharyngeal neuralgia. MVD is recommended for cases where vascular compression is clear and easy to handle. However, for cases with complex vascular compression, tight vascular adhesions, difficult separation, and without clear vascular compression, RHZ could be performed. Its efficiency is equivalent to MVD, and there is no significant increase in complications such as cranial nerve disorders. There are few cranial nerve complications that seriously affect the quality of life of patients. RHZ helps to reduce the risk of ischemia and bleeding during surgery by reducing the risk of arterial spasms and injury to the penetrating arteries by separating the vessels due to separation of vessels during MVD. At the same time, it may reduce the postoperative recurrence rate.

Case Report: Curative effect of OA-PICA protected bypass in severe PICA-complicated vertebral artery stenosis treatment: Results in 3 cases

Objectives

We aimed to explore the results of OA-PICA-protected bypass grafting in patients with severe stenosis of the vertebral artery combined with PICA.

Methods

Three patients with vertebral artery stenosis involving the posterior inferior cerebellar artery, treated by the Department of Neurosurgery of Henan Provincial People's Hospital from January 2018 to December 2021, were retrospectively analyzed. All the patients underwent Occipital Artery-Posterior Inferior Cerebellar Artery (OA-PICA) bypass surgery followed by elective vertebral artery stenting. Intraoperative indocyanine green fluorescence angiography (ICGA) showed patency of the bridge-vessel anastomosis. Postoperatively, the ANSYS software was used to assess the flow pressure changes and vascular shear in combination with the reviewed DSA angiogram. CTA or DSA was reviewed 1-2 years postoperatively, and the prognosis was evaluated by the modified Rankin Scale (mRS) one year postoperatively.

Results

OA-PICA bypass surgery was completed in all patients, with intraoperative ICGA showing a patent bridge anastomosis, followed by stenting of the vertebral artery, and a review of the DSA angiogram. We also employed ANSYS software evaluation of the bypass vessel, which showed stable pressure and low turnover angle, suggesting a low rate of long-term occlusion of the vessel. All patients had no procedure-related complications during their hospitalization, and were followed up for a mean of 24 months postoperatively, with a good prognosis (mRS score of 1) at 1 year postoperatively.

Conclusion

OA-PICA-protected bypass grafting is an effective treatment for patients with severe stenosis of the vertebral artery combined with PICA.

Microsurgical treatment of posterior inferior cerebellar aneurysms based on angioarchitecture supplemented by high-resolution vessel wall MRI: a case series report

BACKGROUND

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging because many are nonsaccular and atherosclerotic. We report our tailored approach to PICA aneurysms, which is based on angioarchitecture supplemented by high-resolution vessel wall MRI (HR-VW MRI) findings.

METHODS

From March 2010 to September 2020, 27 patients with 29 PICA aneurysms underwent surgical treatment in our institution. Since October 2016, HR-VW MRI has been used for aneurysmal wall assessment. Clinical characteristics, radiological data and surgical outcomes were analysed.

RESULTS

Nineteen proximal PICA aneurysms (vertebral artery (VA), P1, P2 and P3) were treated using the far-lateral approach. Ten distal PICA aneurysms (P4, P5) were treated using the suboccipital midline approach. Direct clipping or clip reconstruction was achieved in 19 aneurysms. Ten were trapped in conjunction with extracranial-intracranial or intracranial-intracranial bypass, including three occipital artery-PICA reimplantations, three PICA-VA reimplantations, two PICA-PICA side-to-side anastomoses, one PICA-PICA reimplantation and one PICA-PICA reanastomosis. All aneurysms were eventually completely obliterated and all bypasses remained patent. At the last follow-up, 26 patients (96.2%) achieved a good outcome (modified Rankin Scale score <3). Eight patients underwent HR-VW MRI. Among these, the six aneurysms with focal wall enhancement required bypass and the two with negative enhancement were successfully clipped.

CONCLUSION

PICA aneurysms have a higher frequency of complex features such as large or giant size and fusiform or dissecting morphology. Favourable outcomes were achieved with individualised microsurgical strategies based on angioarchitecture. HR-VW MRI may be used as a promising technique to predict aneurysmal atherosclerosis.

Microsurgical treatment of posterior inferior cerebellar aneurysms based on angioarchitecture supplemented by high-resolution vessel wall MRI: a case series report

BACKGROUND

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging because many are nonsaccular and atherosclerotic. We report our tailored approach to PICA aneurysms, which is based on angioarchitecture supplemented by high-resolution vessel wall MRI (HR-VW MRI) findings.

METHODS

From March 2010 to September 2020, 27 patients with 29 PICA aneurysms underwent surgical treatment in our institution. Since October 2016, HR-VW MRI has been used for aneurysmal wall assessment. Clinical characteristics, radiological data and surgical outcomes were analysed.

RESULTS

Nineteen proximal PICA aneurysms (vertebral artery (VA), P1, P2 and P3) were treated using the far-lateral approach. Ten distal PICA aneurysms (P4, P5) were treated using the suboccipital midline approach. Direct clipping or clip reconstruction was achieved in 19 aneurysms. Ten were trapped in conjunction with extracranial-intracranial or intracranial-intracranial bypass, including three occipital artery-PICA reimplantations, three PICA-VA reimplantations, two PICA-PICA side-to-side anastomoses, one PICA-PICA reimplantation and one PICA-PICA reanastomosis. All aneurysms were eventually completely obliterated and all bypasses remained patent. At the last follow-up, 26 patients (96.2%) achieved a good outcome (modified Rankin Scale score <3). Eight patients underwent HR-VW MRI. Among these, the six aneurysms with focal wall enhancement required bypass and the two with negative enhancement were successfully clipped.

CONCLUSION

PICA aneurysms have a higher frequency of complex features such as large or giant size and fusiform or dissecting morphology. Favourable outcomes were achieved with individualised microsurgical strategies based on angioarchitecture. HR-VW MRI may be used as a promising technique to predict aneurysmal atherosclerosis.

Traumatic cervical vertebral artery aneurysm associated with suicidal stabs

Background

Cervical vertebral artery (VA) aneurysm occasionally develops in association with penetrating injury. However, its treatment strategy is not yet determined.

Case Description

A 50-year-old woman with bipolar disorder attempted suicide by stabbing herself in the lateral neck. At presentation, focal neurological deficits were not observed. Spinal computed tomography (CT) showed unclear delineation of the VA in the right C4/5 intervertebral foramen. CT performed 7 days later identified an aneurysm of the right VA at C4/5, with abnormal arteriovenous shunts between the aneurysm and paravertebral venous plexus. The patient underwent coil embolization of the VA segment involving the aneurysm on the same day that was complicated by cerebellar ataxia due to procedure-associated infarction.

Conclusion

Traumatic VA aneurysms associated with penetrating injuries should be carefully managed with a detailed presurgical evaluation of the relevant cranial and spinal structures.

Intervention for symptomatic vertebrobasilar disease

Disease of the vertebral (VA) and basilar arteries (BA) can lead to stroke of the posterior circulation and may warrant management strategies which differ from the anterior circulation. The mechanism and location of the disease determine its natural history and therefore affect the relative risks and benefits of the possible treatment options. Vertebrobasilar (VB) atherosclerotic disease is a source of both hemodynamic and embolic posterior circulation stroke. Advances in medical therapy have decreased the rate of stroke after initial symptomatic presentation. Antiplatelet therapy, blood pressure control, and optimization of secondary risk factors can reduce recurrent stroke risk in both intracranial and extracranial VB disease. However, symptomatic intracranial disease is still associated with a high risk of subsequent stroke, particularly those with hemodynamic compromise who represent a higher risk population. Patients with hemodynamic impairment may benefit from judicious application of endovascular and microsurgical interventions to augment blood flow. Stenting, angioplasty alone, bypass surgery, and endarterectomy, represent endovascular and surgical tools available to address medically refractory VB disease. Apart from atherosclerotic disease, dissection is another etiology of VB stroke, most frequently affecting the extracranial VA. Treatment is predominantly antithrombotic therapy although surgical or endovascular intervention can be required in rare cases of persistent embolism or hemodynamic compromise. In contrast, extrinsic compromise of the VA represents a separate extracranial pathology and is best treated with mechanistically targeted surgeries or extracranial bypass.

[Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]

Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.

Clinical importance of the occipital artery in vascular lesions: A review of the literature

The occipital artery (OA) is a critical artery in vascular lesions. However, a comprehensive review of the importance of the OA is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the OA to increase our understanding of its role in vascular lesions. We also provided our typical cases to illustrate the importance of the OA. The OA has several variations. For example, it may arise from the internal carotid artery or anastomose with the vertebral artery. Therefore, the OA may provide a crucial collateral vascular supply source and should be preserved in these cases. The OA is a good donor artery. Consequently, it is used in extra- to intracranial bypasses for moyamoya disease (MMD) or aneurysms. The OA can be involved in dural arteriovenous fistula (DAVF) and is a feasible artery for the embolisation of DAVF. True aneurysms and pseudoaneurysms can occur in the OA; surgical resection and embolisation are the effective treatment approaches. Direct high-flow AVF can occur in the OA; embolisation treatment is a good option in such cases. The OA can also be involved in MMD and brain arteriovenous malformation (AVM) by forming transdural collaterals. For a patient in the prone position, if occipital and suboccipital craniotomies are performed, the OA can also be used for intraoperative angiography. In brief, the OA is a very important artery in vascular lesions.