Microsurgical Clipping of Intracranial Aneurysms in the Endovascular Era

Robotic Arm-Protected Microsurgical Pericallosal and Middle Cerebral Artery Aneurysm Clipping: A Technical Note and Case Series

BACKGROUND

Managing intraoperative aneurysm rupture (IAR) during intracranial aneurysm clipping can be challenging given the excessive hemorrhage and limited field of view under the microscope for visualizing the proximal artery and safe temporary clipping.

OBJECTIVE

To describe the first known use of robotic arm for safeguarding IAR in microsurgical aneurysm clipping.

METHODS

A robotic arm was used to safeguard 3 microsurgical clipping cases (1 pericallosal and 2 middle cerebral artery) performed by a single surgeon. The device was installed onto the side rail of the operating table along with the clip applier attachment. After dissecting the cerebral artery segment proximal to the aneurysm, a temporary aneurysm clip was loaded and established at the appropriate segment before dissecting distally toward the aneurysm.

RESULTS

Setup for the robotic arm and temporary clip was simple, quick, precise, and without any unforeseen accommodations needed in all 3 instances. The temporary clip acted as an emergency gate and could be deployed either manually or remotely through a controller. IAR occurred in case 1, and the robotic-assisted temporary clip deployment achieved immediate hemostasis without complications. This method bypassed the need for significant suctioning, packing, and further exploration for safe temporary clipping. Case 2 and 3 demonstrated the feasibility for middle cerebral artery protection and ease of intraoperative readjustment.

CONCLUSION

This technical note highlights the feasibility and relative ease of using a robotic arm as a safeguard device, and it enables on-demand control of proximal blood flow and may enhance the safety of microsurgical aneurysm procedures.

Temporary vessel occlusion in cerebral aneurysm surgery guided by direct cortical motor evoked potentials

BACKGROUND

Temporary clipping is an important tool in the vascular neurosurgeon's armamentarium. We routinely utilize intraoperative neurophysiological monitoring (IONM) for complex brain aneurysm surgery cases, relying on direct cortical motor evoked potential (DCMEP) alerts to guide the duration of temporary clipping. Previous studies have argued for relatively short and intermittent temporary clipping strategies. In this study, we sought to assess the maximal permissive temporary clipping time during complex aneurysm surgery. To do this, we assessed patient outcome in relation to temporary clip duration guided by DCMEP.

METHODS

We queried our prospectively collected neuromonitoring database for anterior circulation aneurysm cases where temporary clipping was utilized by a single cerebrovascular surgeon between 2018 and 2021. Operative and IONM reports were reviewed. Patients in whom the duration of temporary clipping could not be determined were excluded. The operative strategy permissively allowed continuous temporary clipping as long as no neuromonitoring alerts were encountered. Maximal permissive parent artery occlusion time (Clip_max) was recorded as the longest duration of tolerated temporary vessel clipping without decrement in DCMEP.

RESULTS

A total of 41 complex anterior circulation aneurysm clipping cases met criteria for this study. The mean Clip_max for all cases was just over 19 min and did not differ between ruptured and unruptured aneurysms. Initial alert times were not found to be predictive of final permissive temporary clip duration after re-perfusion. In 100% (41/41) of cases, the aneurysm was completely clip occluded without residual on catheter angiogram. Stable or improved modified Rankin Score was achieved in 98% (40/41) of cases at 3-month follow-up.

CONCLUSIONS

This study demonstrates that using DCMEP can facilitate relatively long but safe temporary clipping durations in complex anterior circulation aneurysm surgery. In the endovascular era with only a limited subset of technically challenging aneurysms needing open surgical treatment, extended permissive temporary clipping guided by DCMEPs can significantly enhance a surgeon's ability to achieve excellent technical and clinical outcomes.

Retreatment of previously treated intracranial aneurysm: Procedural complications and risk factors for complications

OBJECTIVE

Intracranial aneurysm (IA) is a frequent vascular malformation that can be managed by endovascular treatment (EVT) or microsurgery. A previously treated IA can recanalize, which may require further treatment. The aim of our study was to evaluate procedural complications related to IA retreatment and their risk factors.

METHODS

All patients retreated for IA between 2007 and 2017 in 4 hospitals were included. We retrospectively reviewed the frequency of procedural complications of IA retreatment, defined as death or≥1-point increase in modified Rankin score 24h after the procedure. We then screened for risk factors of procedural complications by comparing the characteristics of patients with and without complications.

RESULTS

During the inclusion period, 4,997 IAs were treated in our 4 institutions. Of these, 237 (4.7%) were retreated. 29 (12.2%) had≥1 procedural complication. However, severe complications, defined as death or dependency at 1 month, occurred only in 3 patients (1.3%). The only risk factor for complications was microsurgical clipping as retreatment.

CONCLUSIONS

Procedural complications during IA retreatment were frequent but, in most cases, retreatment did not lead to death or severe disability. The only risk factor for complications of IA retreatment was clipping as retreatment. However, the design of the study did not allow any conclusion to be drawn as to the optimal means of aneurysm retreatment, and further studies are needed.