Surgical Treatment of Mirror Middle Cerebral Artery Aneurysms: Bilateral and Unilateral Approach

Investigation of the Use of Hollow Elastic Biomodels Produced by Additive Manufacturing for Clip Choice and Surgical Simulation in Microsurgery for Intracranial Aneurysms

BACKGROUND

Intracranial aneurysms (IAs) are dilatations of the cerebral arteries, whose treatment is commonly based on the implant of a metallic clip on the aneurysm neck. Despite the dissection and understanding of the surgical anatomy of the IA when often only parts of it are visible, the choice of the ideal clip to be used is one of the surgical difficulties. Although current imaging tests guarantee IA visualization, currently there is no planning method that allows for a real three-dimensional (3D) visualization for optimal choice of clip prior to surgery. The aim of this study is to evaluate whether IA biomodels generated by additive manufacturing methods are useful for surgical clip selection in microsurgeries for IA.

METHODS

Three-dimensional (3D) IA biomodels of 10 patients with IA were evaluated using computerized tomography, surgical microscope, and 3D printer. The research was divided into 4 phases as follows: development of the 3D biomodels, evaluation of the biomodel dimensional characteristics, surgical planning evaluation with the biomodel and its clipping effectiveness, and evaluation of the actual surgical simulation process within the models.

RESULTS

Ten 3D biomodels were obtained, made of a malleable and hollow part, formed by the IA and related arteries, and another rigid part, mimicking the skull and other arteries of the skull base. Based on these 3D models, 10 clips were chosen during the surgical planning, and all exactly matched the clip characteristics used during the actual surgeries. The surgical simulation with the biomodels performed by 2 neurosurgeons still in training obtained 100% accuracy in the identification of the clips that were eventually used during the actual surgeries.

CONCLUSIONS

3D biomodels generated by additive manufacturing methods were effective for surgical clip selection in microsurgeries for IA, reducing surgical time, increasing cerebral angioarchitecture understanding, and providing more safety in this type of surgery.

Safety and Efficacy of Bilateral Flow Diversion for Treatment of Anterior Circulation Cerebral Aneurysms

BACKGROUND

Nearly 20% of individuals with an aneurysm will have multiple aneurysms-these individuals are at increased risk of subarachnoid hemorrhage. Treatment of bilateral aneurysms with flow diverters (FDs), or Pipeline embolization device, has not yet been established as an effective therapy. We evaluated the safety and efficacy of a 2-stage treatment of bilateral aneurysms with Pipeline embolization devices placed 6 months apart.

METHODS

We performed a retrospective review to analyze the clinical and angiographic outcomes of 16 individuals with bilateral aneurysms treated with 2-stage flow diversion at a tertiary referral center from January 2010 to July 2018.

RESULTS

Of the 16 patients with 33 aneurysms treated with bilateral flow diversion, 1 had 2 aneurysms treated with a single FD on the contralateral side. The aneurysms treated were ophthalmic, superior hypophyseal, posterior communicating, or cavernous segment aneurysms, with an average size of 6.5 mm. No major complications, such as in-stent stenosis, thromboembolic events, distal intraparenchymal hemorrhage, rerupture, stent migration, or neurological death, were recorded. All the patients had good functional outcomes. At the 24-month follow-up examination, 81% of aneurysms showed complete occlusion. No aneurysm required repeat treatment.

CONCLUSIONS

The results from the present study have demonstrated that 2-stage treatment of bilateral aneurysms with FDs is both safe and efficacious. The timing of contralateral FD stent placement is critical. We found that 6 months allows for adequate neurological recovery and stent endothelialization.

Intracranial Mirror Aneurysm: Epidemiology, Rupture Risk, New Imaging, Controversies, and Treatment Strategies

There are some controversies about the surgical treatment strategy of mirror aneurysms. Whether to choose 1-stage or 2-stage surgery, bilateral or unilateral craniotomy, or surgical or interventional treatment are the main points in dispute. In this review, the different surgery strategies faced by patients are discussed. Different surgical methods are adopted based on the patient's individual state and the location and size of the aneurysm. A new imaging method is introduced using 3D Slicer, which clearly recognizes the relationship among aneurysm, brain tissue, skull, and nerve. The 3D Slicer can help surgeons undertake adequate preoperative preparation. In addition, we also introduce some ruptured factors (e.g., age, gender, hypertension, morphologic, and hemodynamic) concerning mirror aneurysm. Systematic discussion of the controversies and methods in surgical treatment of mirror aneurysms may provide new perspectives in future research for the prevention and treatment of mirror aneurysms.

Surgical Treatment Strategy and Perioperative Analysis of Patients With Intracranial Mirror Aneurysms

OBJECT

Intracranial mirror aneurysm is a type of multiple aneurysms, which is rare in clinical and literature. There is no unified conclusion on the treatment strategy of mirror aneurysms. Therefore, our study evaluated the surgical approach and prognosis of a series of mirror aneurysms, and explored the clinical features and treatment strategies of mirror aneurysms.

METHODS

This study retrospectively analyzed the clinical features, imaging data, treatment methods and post-hospital results of 67 cases of mirror aneurysms admitted to our department from December 1997 to April 2018.

RESULTS

There were 20 males and 47 females with an average age of 53.6 years. Mirror aneurysms are mainly located in the posterior communicating artery and middle cerebral artery. Of 67 patients, 1-stage unilateral craniotomy with bilateral aneurysms in 18 cases, 1-stage bilateral craniotomy with bilateral aneurysms in 17 cases, staged treatment of bilateral aneurysms in 13 cases, and 19 cases only treated the responsible aneurysms. 57 cases with good recovery; 7 cases were self-care; 1 case was heavy disability; 2 cases were dead. In parallel, 8 cases had different degrees of cerebral infarction, 3 cases of hydrocephalus, 3 cases of oculomotor nerve injury, 2 cases died of cerebral hernia resulted from intracranial hypertension, and the remaining 53 cases were better.

CONCLUSIONS

The treatment of the mirror aneurysm should be based on the location, size, shape of the aneurysm, the patient's clinical manifestations and the surgeon's experience to choose a personalized treatment.

Effect Analysis of Microsurgical Clipping and Endovascular Embolization for the Treatment of Middle Cerebral Artery Aneurysms

OBJECTIVE

To evaluate the safety and effectiveness of microsurgical clipping and endovascular embolization for the treatment of middle cerebral artery aneurysm (MCAA).

MATERIAL AND METHODS

The clinical data of 482 patients with MCAA treated with microsurgical clipping or endovascular embolization were analyzed retrospectively. According to whether the aneurysms were ruptured, patients were divided into a ruptured group and an unruptured group. Demographics, clinical manifestation, and postoperative complications were recorded.

RESULTS

In the microsurgical clipping group (257 patients), there were 114 male and 143 female patients. The mean age was (55 ± 10) years and the mean course of disease was 3 (1, 36) days. The total numbers of MCAA were 274, including 179 ruptured aneurysms and 95 unruptured aneurysms. In the endovascular embolization group (225 patients), there were 98 male and 127 female patients. The mean age was (54 ± 11) years and the mean course of disease was 10 (1, 55) days. The total numbers of MCAA were 234, including 126 ruptured aneurysms and 108 unruptured aneurysms. There was no difference between the incidence of complications in the ruptured and unruptured groups. The outcome of the endovascular embolization group was better than the microsurgical clipping group in ruptured aneurysms (P = 0.000). The recurrence rate of the endovascular embolization group was greater than the microsurgical clipping group in ruptured aneurysms (P = 0.023).

CONCLUSIONS

Both microsurgical clipping and endovascular embolization were safe and effective methods for the treatment of MCAA, but patients with ruptured MCAAs treated with endovascular embolization were more likely to experience recurrence.