EC-IC Bypass: “Learning Curve” Experiences of Initial 100 Bypasses in Bangladesh
Authors: Chowdhury Forhad , Haque Mohammod Raziul , Rumi Jalaluddin Muhammad , Hossain Monir , Arifin Mohammod Shamsul , Talukder Moajjem Hossain , Goel Atul , Sarker Mainul Haque 
Published: October 2022

Abstract
Objectives Extracranial to intracranial (EC-IC) bypass is an important part of the armamentarium of a neurosurgeon in managing different vascular and neoplastic pathologies. Here, we report our initial experiences of EC-IC bypasses as experiences in the ‘learning curve’, including preparation and training of the surgeon, getting cases, patient selection, imaging, operative skills and microtechniques, complications, follow-up, and outcome. Lessons learned from the ‘learning curve experiences’ can be very useful for young vascular neurosurgeons who are going to start EC-IC bypass or have already started to perform and find themselves in the learning curve.
Methods From July 2009 to September 2018, 100 EC-IC bypasses were performed. We looked back to these cases of EC-IC bypass as our initial or ‘learning curve’ experiences. The recorded data of patient management (EC-IC bypass patient) were reviewed retrogradely. Our preparation for EC-IC bypass was described briefly. Case selection, indications, preparation of the patient for operation, techniques and technical experiences, preoperative difficulties and challenges, postoperative follow-up, complications, patency status of the bypass, and ultimate results were reviewed and studied.
Result A total of 100 bypasses were performed in 83 patients, of which 43 were male and 40 were female. The age range was from 04 to 72 years old (average 32 years old). Eleven patients were lost to follow-up postoperatively after 3 months and they were not even available for telephone follow-up. The follow-up period ranged from 3 to 120 months (average of18.4 months). Eight bypasses were high flow bypasses, whereas the number of low flow STA-MCA bypasses was 92. Indication of bypass were (in 83 cases):1. Arterial stenosis/occlusion/dissection causing cerebral ischemia (middle cerebral artery [MCA] stenosis/occlusion-05, MCA dissection-04, internal carotid artery [ICA] occlusion-19); 2. Intracranial aneurysm-30; 3. Moya-Moya disease-21; and 4. Direct carotid cavernous fistula [CCF]-04. Common clinical presentation was hemiparesis & dysphasia in ischemic group with history of transient ischemic attack (H/O TIA) (including Moya Moya disease). Features of subarachnoid hemorrhage (SAH) were the presenting symptoms in intracranial aneurysm group. The average ischemic time, due to clamping of recipient artery, was 28 minutes (range: 20–60 minutes). There was no clamp-related infarction. Two anastomoses were found thrombosed intraoperatively.One preoperatively ambulant patient deteriorated neurologically in the postoperative period. She developed hemiplegia but improved later. Here, the cause seemed to be hyperperfusion. Headache resolved in all cases. TIA and seizures were also gone postoperatively. Ophthalmoplegia recovered in all cases in which it was present, except in one CCF, in which abducent nerve palsy persisted. Complete unilateral total blindness developed in one patient postoperatively (due to ophthalmic artery occlusion), where high flow bypass with ICA occlusion were performed. Red eye and proptosis were cured in CCF cases. Motor and sensory dysphasia improved in all cases in which it was present, except for one case in which preoperative global aphasia converted to sensory aphasia in the postoperative period. Three patients died in the postoperative period. The rest of the patients improved postoperatively. All patients were ambulant with static neurostatus and without new stroke/TIA until the last follow-up. All bypasses were patent until the last follow-up.
Conclusion The initial experiences of 100 cases of EC-IC bypass revealed even in inexperienced hand mortality and morbidity in properly indicated cases were low and result were impressive according to the pathological group and aim of bypass. Lessons learned from these experiences can be very helpful for new and beginner bypass neurosurgeons