Application of protective superficial temporal artery to middle cerebral artery bypass through the lateral supraorbital approach: Technical note

OBJECTIVE

The lateral supraorbital (LSO) approach is a minimally invasive craniotomy widely used in the surgical treatment of intracranial aneurysms (IAs). A protective bypass is considered a safety measure in high-risk and complex clipping procedures to maintain distal cerebral flow. However, the protective bypass has so far only been applied through a pterional or larger craniotomy. We aimed to describe the characteristics of the superficial temporal artery to middle cerebral artery (STA-MCA) bypass through the LSO craniotomy to treat complex IAs.

METHODS

We retrospectively identified six patients with complex IAs who underwent clipping and a protective STA-MCA bypass through the LSO approach between January 2016 and December 2020. The STA donor artery was harvested through the same curvilinear skin incision with a small extension, and it was anastomosed to the opercular segment of the MCA. Subsequently, aneurysm clipping followed standardized steps.

RESULTS

Anastomosis was successful in all patients. Despite requiring temporary occlusion of the parent artery, all aneurysms were successfully clipped without any neurological deterioration.

CONCLUSIONS

A protective STA-MCA bypass is feasible through the LSO approach with certain technical modifications. This technique helps protect distal cerebral flow for safe clip placement in the treatment of complex IAs with the associated benefits of a less invasive craniotomy.

How I do it: left posterior cerebral artery P1-2 segment dissecting aneurysm distal clipping via an A1-RAG-P2 bypass

BACKGROUND

Posterior cerebral artery (PCA) P1-2 segment dissecting aneurysms are difficult because regular craniectomy aneurysm clipping or intravascular interventional therapy is not applicable.

METHOD

We report distal clipping of a PCA P1-2 segment dissection aneurysm with an anterior cerebral artery (ACA) A1-radial artery graft-PCA P2 bypass.

CONCLUSION

This case demonstrates the value of an ACA-RAG-PCA bypass in the therapy of a PCA dissecting aneurysm.

Vascular Lesions of the Pineal Region: A Comprehensive Review of the Therapeutic Options

OBJECTIVE

Vascular lesions of the pineal region comprise aneurysms of the pineal region, arteriovenous malformations, cavernous malformations, and vein of Galen malformations. In the present report, we have offered an extensive review of each vascular pineal region lesion.

METHODS

We performed an extensive literature review, focusing on the current therapeutic options available for the different vascular lesions of the pineal region.

RESULTS

Vascular lesions of the pineal region are rare. Microneurosurgery remains a valid treatment of cavernomas, arteriovenous malformations, and aneurysms. Endovascular treatments seem to be the first option for the vein of Galen malformations, followed by microneurosurgery. Radiosurgery seems beneficial for small-size arteriovenous malformations. Complex and large vascular lesions will require a combination of multiple treatments.

CONCLUSIONS

Vascular lesions of the pineal region are complex, uncommon diseases. Thus, definitive therapeutic modalities for these lesions require further research.

Superficial Temporal Artery (STA)-Posterior Cerebral Artery (PCA) Bypass through Zygomatic Anterior Temporal Approach for Complex PCA Aneurysm: Technique Notes

BACKGROUND

Posterior cerebral artery (PCA) aneurysms are rare and the majority are giant, dissecting, or fusiform in morphology. Proximal occlusion of PCA without revascularization causes a high risk of ischemic complications. This study aimed to evaluate the safety and validity of using superficial temporal artery (STA)-posterior cerebral artery (PCA) Bypass through zygomatic anterior temporal approach in complex PCA aneurysms.

METHODS

Trapping or resecting of the aneurysms and reconstruction of the distal PCA through a zygomatic anterior temporal approach were performed in 6 patients from June 2017 to August 2020. Postoperative angiography was used to confirm the obliteration of the aneurysms and the patency of bypass artery. Neurologic function was assessed by the modified Rankin Scale.

RESULTS

Four male and 2 female patients with a mean age of 43.8 years (Range, 21-58 years) were assessed. Subarachnoid hemorrhage occurred in 5 patients, including 3 patients with Hunt-Hess grade IV, 2 patients with grade III, and 1 patient with grade I. All PCA aneurysms were treated with trapping or resecting of the aneurysms and revascularization of the distal PCA. Postoperatively, all aneurysms were eliminated and no new permanent neurological deficit was found. During the follow-up, Modified mRS of all patients were improved: There were 2 patients with mRS Score 0, 1 patient with mRS Score 1, 1 patient with mRS Score 3, and 2 patients with mRS Score 4. The long-term graft patency rate was 100%.

CONCLUSION

The STA-PCA bypass appears to be a safe and effective method for the treatment of complex PCA aneurysms requiring supplementing the blood flow in the area of the PCA. We established a surgical route, allowing the procedure to be done through the zygomatic anterior temporal approach. This approach provides adequate operative field exposure and reduces retraction of the temporal lobe.

Presigmoid Transpetrosal Approach for Superficial Temporal Artery to Distal Posterior Cerebral Artery Bypass and Trapping of Aneurysm

BACKGROUND AND IMPORTANCE

Aneurysms of the posterior cerebral artery (PCA) are uncommon, estimated at less than 1% of all cerebral aneurysms, and less than half occur distal to the P1/2 junction. Unfortunately, the conventional bypass approach for PCA aneurysms—primarily occipital artery to distal PCA cortical branches—has a history of unsatisfying results.

CLINICAL PRESENTATION

A 42-yr-old female presented with Fisher 3 Hunt-Hess 2 subarachnoid hemorrhage secondary to ruptured distal PCA aneurysm. She was initially evaluated by the endovascular service, but due to recent subarachnoid hemorrhage, endovascular treatment with flow diversion and/or vessel sacrifice was felt to be relatively contraindicated and the patient was referred for surgical evaluation for possible bypass. The patient subsequently underwent surgery for trapping of aneurysm and concomitant superficial artery to distal PCA bypass.

CONCLUSION

A novel approach for the treatment of a ruptured distal PCA aneurysm is described, consisting of posterior transpetrosal exposure and division of the tentorium with superficial temporal artery to P3 bypass.

Selection of approach and bypass for fetal-type posterior cerebral artery aneurysm: illustrative cases

BACKGROUND

Unlike in aneurysms of the adult-type posterior cerebral artery (PCA), in aneurysms of the fetal-type PCA, parent artery occlusion (PAO) results in vascular insufficiency and major ischemic strokes. Preservation or reconstruction of fetal-type PCAs is necessary to prevent these complications. Furthermore, it is necessary to select an appropriate bypass method and approach for revascularization of the PCA.

OBSERVATIONS

The authors report 2 cases of aneurysms of fetal-type PCAs that were successfully treated with PAO with revascularization. A 38-year-old man with a large unruptured right PCA aneurysm at the postcommunicating (P2) segment underwent trapping with superficial temporal artery–PCA bypass via the anterior temporal and subtemporal approaches. In addition, a 45-year-old woman with a left PCA aneurysm at the quadrigeminal (P3)–cortical (P4) segments resulting in subarachnoid hemorrhage underwent proximal clipping of the P3 segment via the occipital interhemispheric approach with an occipital artery–PCA bypass. Although she had perforator infarction, major ischemic stroke was prevented, and aneurysm occlusion was accomplished in both cases.

LESSONS

Aneurysms of fetal-type PCAs pose a risk of ischemia due to PAO. The combined use of bypass and revascularization should be considered to prevent major ischemic stroke after occlusion of the fetal-type PCA. However, perforator infarction is a concern.

Extreme Lateral Supracerebellar Infratentorial Approach (ELSCIT) for Occipital Artery-to-Posterior Cerebral Artery Bypass: Results in 3 Cases

OBJECTIVE/BACKGROUND

The need for revascularization of the distal posterior cerebral artery (PCA) in the treatment of PCA aneurysms is a contentious issue. Approaches to the PCA, such as the subtemporal route, carry significant perioperative risk. This risk at times outweighs the risk of ischemia associated with endovascular PCA sacrifice. This paper describes the use of an extreme lateral supracerebellar infratentorial (ELSCIT) approach as an alternative technique for distal PCA revascularization.

METHODS

Between 2016 and 2019, 3 patients underwent a PCA bypass via the ELSCIT approach for the treatment of a PCA aneurysm. In all cases, an end-to-side anastomosis to the P2- or P3-segment of the PCA was made, with the occipital artery as a donor. Bypass procedures were followed by endovascular parent artery occlusion, without ischemic complications.

RESULTS

In all 3 cases, the ELSCIT approach offered a broad enough surgical corridor to perform an occipital artery-to-PCA bypass. One patient suffered a cerebrospinal fluid leak that was surgically treated. Patients' clinical conditions were stable on follow-up (mean follow-up of 34 months). All 3 aneurysms remained occluded, and no ischemia was detected on magnetic resonance imaging.

CONCLUSIONS

The ELSCIT approach offers an alternative route to the distal PCA for extracranial-to-intracranial bypass with seemingly low perioperative morbidity and good surgical access to the PCA.

Safety, Feasibility, and Patient-Rated Outcome of Sonolucent Cranioplasty in Extracranial-Intracranial Bypass Surgery to Allow for Transcranioplasty Ultrasound Assessment

Objective

We sought to analyze the safety and feasibility of elective sonolucent cranioplasty in the setting of extracranial-to-intracranial (EC-IC) bypass surgery to monitor bypass patency using ultrasound.

Methods

Patients who underwent direct EC-IC bypass surgery agreed to sonolucent cranioplasty at the time of surgery and received a sonolucent polymethyl methacrylate (PMMA) implant. Besides monitoring clinical outcome, all patients received transcranioplasty ultrasound (TCUS) on postoperative day 1 and at last follow-up. In addition, bypass patency was confirmed using catheter angiogram and fit of implant using computed tomography. Patient-rated outcome was assessed through phone questionnaire.

Results

EC-IC bypass surgery with PMMA cranioplasty was successful in all 7 patients with patent bypasses on postoperative angiogram. Direct TCUS was feasible in all patients, and bypass patency was monitored. There were no complications such as postoperative hemorrhagic/ischemic complications related to the bypass procedure in this patient population, as well as no complications related to the PMMA implant. Postoperative computed tomography showed favorable cosmetic results of the PMMA implant in both the pterional area for superficial temporal artery−middle cerebral artery bypasses and parietooccipital area for occipital artery−middle cerebral artery bypasses as confirmed by high-rated overall patient satisfaction with favorable cosmetic, pain, and sensory patient-rated outcomes.

Conclusions

In this study we were able to show that this novel technique is safe, allows for patency assessment of the EC-IC bypass using bedside TCUS technique, and is cosmetically satisfying for patients.

Superficial temporal artery-superior cerebellar artery bypass and direct clipping of a large unruptured superior cerebellar artery aneurysm through subtemporal approach: Surgical video

Background:

Superior cerebellar artery (SCA) aneurysms are rare. Current treatments include: direct clipping, trapping ± bypass, and endovascular methods (coiling, stenting, or flow diversion). Due to specific characteristics (wide base, location, and shape), a major challenge while dealing with SCA aneurysms is to preserve the flow of the parent artery and perforators. This video demonstrates a revascularization procedure, and clip reconstruction of a large unruptured basilar artery (BA)/SCA aneurysm performed through the subtemporal approach.

Case Description:

A 60-year-old woman presented with dizziness and headaches. Computed tomography angiography (CTA) and digital subtraction angiography showed a right unruptured large BA/SCA aneurysm. After multidisciplinary discussion, and considering gender, age, risk factors of the patient. Endovascular treatment was considered with a high risk of ischemic complications. Therefore, the patient was consented for a superficial temporal artery (STA)-SCA bypass through subtemporal approach followed by direct clipping/ trapping of the aneurysm. Postoperative CTA showed occlusion of the aneurysm and patency of the parent vessels. Postoperatively, the patient experienced immediate transient left mild monoparesis and right IV nerve palsy, which recovered completely at 6-months follow-up.

Results:

Surgical treatment of SCA aneurysms is decreasing due to the existence of endovascular therapies such as stents and flow diverters. However, some cases may necessitate surgical treatment and revascularization procedures to maintain the blood flow of the parent artery and to treat the previous lesion.

Conclusion:

The STA-SCA bypass through the subtemporal approach is a feasible option to maintain the blood flow of the parent artery in cases of SCA requiring surgical treatment and trapping/direct clipping of the aneurysm.

The Subtemporal Approach to the Lateral Midbrain with and without Zygomatic Osteotomy: An Anatomical Study

The subtemporal approach provides a narrow operative corridor to the crus cerebrum and adjacent structures of the crural, interpeduncular, and ambient cistern. Addition of a zygomatic osteotomy widens this narrow corridor and spares retraction of the temporal lobe. We investigate and compare the morphometric parameters of the subtemporal approach with versus without zygomatic osteotomy. On each side of four cadaveric heads, a temporal craniotomy was performed to gain access to the crus cerebrum and adjacent subarachnoid cisterns using a subtemporal approach. Operative corridor width and corridor working angle were measured with and without brain retraction on each specimen side. Next, a zygomatic osteotomy was performed followed by full downward reflection of the temporalis muscle and further drilling of the squamous part of the temporal bone. Lastly, operative corridor width and corridor working angle were measured again for comparison. The subtemporal operating corridor was (mean/SD): 5.8/2.6 mm without retraction, 11.4/4.3 mm with retraction, and 13.5/6.5° working angle. After addition of a zygomatic osteotomy, the operative corridor was 8/9.2/4.3 mm without retraction, 14.7/4.5 mm with retraction, 31.8/3.1° working angle. Zygomatic osteotomy significantly increased the operative corridor working angle of the subtemporal approach. Furthermore, we demonstrate a direct approach into the interpeduncular fossa. Clin. Anat. 32:710-714, 2019. © 2019 Wiley Periodicals, Inc.

Posterior Cerebral Artery Reconstruction by In-Situ Bypass with Superior Cerebellar Artery via Occipital Transtentorial Approach

BACKGROUND

Posterior cerebral artery (PCA) aneurysms are relatively rare, and neck clipping is often difficult due to their fusiform shape. We report a case of a thrombosed aneurysm of the distal PCA for which curative trapping and parent artery reconstruction by in situ bypass were performed through an occipital transtentorial approach (OTA).

CASE DESCRIPTION

A 67-year-old woman had been suffering from numbness in the right face and limbs for 4 months. Radiologic imaging demonstrated a thrombosed aneurysm on a distal portion of the left PCA. Curative trapping of the aneurysm and in-situ bypass between the distal PCA and superior cerebellar artery were performed through the OTA. Before surgery, we had evaluated access to the PCA and feasibility of the bypass in a cadaveric simulation. The PCA was well exposed in the posterior half of the ambient cistern, and the proximity of the distal PCA to the superior cerebellar artery through a tentorial incision was confirmed.

CONCLUSIONS

This OTA could represent a useful option for definitive treatment of distal PCA aneurysms.