Extracranial-intracranial bypass of the bilateral anterior cerebral circulation using a thoracodorsal axis artery-graft
A 19-year-old man was referred to the regional neurosurgical center, having suffered two subarachnoid hemorrhages in the previous two months. A cerebral angiogram demonstrated a large aneurysm affecting the anterior communicating artery and the proximal ends of both the right and left anterior cerebral arteries []. Due to the aneurysm's size and position, trapping it was unlikely to preserve the anterior circulation. Furthermore, perforating vessels involved in the trapped segment would likely be sacrificed, although from angiography this was estimated to be relatively unlikely. Bilateral bypass-grafting was, therefore, considered.\nHis past medical history included treatment for B-cell non-Hodgkin's lymphoma, with subsequent marked bronchiectasis.\nPrior to surgery, he was drowsy with a headache, and had Glasgow coma scale (GCS) score of 15; purposeful movements of all limbs to command, spontaneous eye-opening, and conversing normally. At surgery, bicoronal incisions allowed elevation of a pericranial flap and exposure of the left temporalis muscle. A large craniotomy was performed with the bone-flap pedicled on the left temporalis muscle []. The dura was incised preserving the sagittal sinus, allowing bilateral dural flaps to be opened like the pages of a book. Segments of both the left and right anterior cerebral arteries were prepared for the end-to-side anastomoses. The vessels at this level had an external diameter of approximately 1 mm.\nA thoracodorsal axis artery-graft was harvested with an extensive intramuscular dissection, allowing both the latissimus dorsi and serratus anterior branches of the appropriate calibre to be harvested []. The proximal stem of the thoracodorsal axis artery-graft was of insufficient length to permit direct anastomosis onto the external carotid (ECA) and, therefore, an interpositional vein-graft was harvested from the forearm []. The vein-graft was used to bridge the deficit in length between the thoracodorsal axis artery-graft and the left ECA and passed anterior to the left ear. The graft was tunneled through a slit in the temporalis muscle so that it would not be compressed when the bone flap was replaced []. End-to-side anastomoses were then performed onto each of the anterior cerebral vessels [] and the aneurysm subsequently clipped. The pericranial-flap raised earlier was used to cover the anastomoses and seal any dural leaks, and the bone-flap replaced.\nPostoperatively, he was kept intubated as a neuroprotective measure to prevent excessive demand on the re-perfused cerebrum and allow for better control of the blood-pressure. Due to his pre-existing lung-disease, he required a prolonged period of ventilation due to repeated episodes of chest-infection. He did, however, wake-up and respond neurologically, moving all limbs to command and spontaneously opening his eyes, but due to the necessity for continued intubation, could not speak. He was able to communicate clearly in writing. A single photon emission computed tomography (SPECT) perfusion scan performed 48 hours postoperatively demonstrated perfusion of the frontal lobes of the brain, and a CT scan taken one week postoperatively showed no evidence of infarction. Unfortunately, three weeks following surgery the patient died due to overwhelming sepsis secondary to his pre-existing lung-disease.