A flow self-regulating STA-MCA bypass based on side to side fashion anastomosis for adult patients with moyamoya disease

OBJECTIVE Side to side (S-S) fashion superficial temporal artery-middle cerebral artery (STA-MCA) bypass was reported for treating a special moyamoya disease (MMD) patient with collaterals arising from the donor STA. However, the S-S technique is not routinely performed to date and its benefits are still unknown for adult MMD. The purpose of this study is to investigate the possibility of routine use of the S-S technique for adult MMD. METHODS The authors retrospectively analyzed the clinical data from 50 adult patients (65 hemispheres, including 30 in end to side [E-S] group and 35 in S-S group) with MMD underwent STA-MCA bypass. The patients’ demographics, clinical courses, technical details, intraoperative blood flow, post- and preoperative relative cerebral blood flow (rCBF) values, modified Rankin Scale (mRS) scores and short-term revascularization results were compared between the two groups. RESULTS There was no significant difference observed in terms of baseline characteristics, bypass patency rates, post-/ preoperative rCBF values, incidence of cerebral hyperperfusion syndrome (CHS), improvement of mRS scores and short-term revascularization results between the two groups (P all > 0.05). Intraoperative blood flow analysis showed the increase of STA flow in the E-S group was significantly higher than that of proximal STA flow in the S-S group (P = 0.008 <0.05). Although the increases of proximal and distal recipient flow in the E-S group seemed higher than those in the S-S group, the results were not statistically significant (P = 0.086 in proximal and P = 0.076 in distal). The CHS symptoms were milder and their duration time was much shorter in the S-S group. The follow-up angiographic data of the representative case amazingly demonstrated that all the frontal and parietal STA branch and occipital artery participated in the postoperative collateralization. CONCLUSIONS S-S anastomosis can achieve comparable clinical effects to standard E-S construction. S-S anastomosis used in adult MMD demonstrated mild CHS symptoms with short duration time and had the potential to arouse all scalp arteries as donor sources for revascularization through the intact distal STA by a flow self-regulating fashion. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was partly supported by two projects of the National Natural Science Foundation of China (81671157 and 8217052644). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Institutional Review Board at zhongnan hospital of wuhan university I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors