Double-Interposition Bypass: Technical Case Report of a Novel Intraoperative Bypass Salvage Technique.

[BACKGROUND AND IMPORTANCE] Complex cerebrovascular bypass operations may confer an increased risk of intraoperative complications, such as graft thrombosis. Novel techniques are needed to optimize the management of these challenging cases.

[CLINICAL PRESENTATION] A woman in her late 20s was incidentally diagnosed with a 1.5-cm basilar apex aneurysm, which grew to 3.5 cm over 2 years of active surveillance. Definitive treatment was then recommended with flow reversal and Hunterian ligation of the basilar trunk planned as a radial artery graft (RAG) bypass: M2 (S-Ec) RAG (E-Sc*) P2. Intraoperative graft thrombosis prompted multiple attempted salvage maneuvers; however, complete excision and repeat anastomosis were ultimately required. The procedure was completed using a novel double-interposition technique, with ligation of the index RAG approximately 1 cm proximal to the distal anastomosis (final bypass: M2 [S-Ec*] RAG [E-Ec*] RAG' [E-Sc] P2). These technical modifications yielded a less deep recipient site for the repeat bypass and an end-to-end anastomosis rather than an end-to-side anastomosis, collectively facilitating a more efficient and facile salvage. The patient recovered well from surgery, and flow reversal was successfully achieved within the aneurysm.

[CONCLUSION] Despite the increased risk of intraoperative thrombosis with complex cerebrovascular bypass operations, facility with salvage techniques can lead to technically and clinically excellent outcomes. We report the successful use of a novel fourth-generation double-interposition bypass that shortens the working distance and uses a more favorable anastomosis technique. This bypass may facilitate safe and efficient microsurgery in patients who require complete revision of an intracranial-intracranial construct.