ORIGINAL ARTICLE Intraoperative digital subtraction angiography in neurovascular disorders R Boer" FCS(SA) and DO Royston'" FFRad(D)SA # Department of Neurosurgery, Wentworth Hospital, Durban • Department of Radiology, Wentworth Hospital. Durban The importance of intraoperative DSA in the management of complex neurovascular disorders is explained. Both neu rosurgeon and radiologist work in theatre as a team. Abstract Intraoperative digital subtraction angiography is useful for assessing the results of complex neurovascular procedures. Fifty- five patients with A VMs, aneurysms (Berry and bacterial), carotid-cavernous fistulae, spontaneous intracranial haemorrhages and penetrating head injuries had intraoperative angiograms. Sixteen of these patients had findings on the angiogram which altered the surgical procedure. There were no angiographic complications. We found intraoperative digital subtraction angiography a valuable adjunct to several neurovascular procedures. 24 SAJOURNAL OF RADIOLOGY. September 1996 Introduction In the past neurosurgeons have relied mainly on direct visualisation or postopera- tive angiography to assess the results of complex neurovascular procedures. Ad- vances in equipment have made it easier and faster to perform intraoperative angiography. Intraoperative angiography facilitates the immediate assessment of neurovascular procedures and allows the surgeon to correct any technical defects.We report our experience with intraoperative angiography at Wentworth Hospital. Patients and methods From April 1990 to December 1994 fifty- five intraoperative angiograms were per- formed at Wentworth Hospital. Angiograms were done via a transfemoral approach. A sheath was introduced preoperatively and flushed with heparinised saline (2000U/1 000ml of nor- mal saline at30ml!hr). The patient was then anaesthetised and placed in the required position for surgery. The theatre table had a radiolucent exten- sion to facilitate screening of the aortic arch and neck vessels. The standard three-pin Mayfield-Kees head-holder was used as required. (Radiolucent carbon fibre head- holders are available). Angiography was performed with a mobile digital subtraction imaging system (Ziehm Exposeop CB7 -D). This consisted of a C-arm, digital processing unit, dual video monitors and an image storage unit. The appropriate carotid or vertebral artery was catheterised during or at the end of the procedure asrequired by the surgeon. Contrast Iohexol (6-1 Oml) (Omnipaque, Nycomed) was injected by hand to deline- ate the relevant vascular anatomy. The im- ages were reviewed immediately. If it was felt that the surgical procedure was in any way unsatisfactory or incomplete further surgery was performed under the same topage25 I ntraoperative cj igital subtraction angiography in neurovascular disorders frompage24 anaesthetic. The sheath was removed at the end of the procedure. Postoperatively the groin was monitored for the devel- opment of haem atom a and peripheral pulses checked. Routine postoperative angiography was not performed. Results Fifty-five intraoperative angiograms have been performed at Wentworth Hospital. The surgical procedures performed are detailed in Table 1. There were no angiographic complications Table I: Intraoperative angiograms performed at Wentworth Hospital (1990-1994) Aneurysms (Berry) 17 Arteriovenous malformations 17 Carotid-cavernous fistulas 5 Spontaneous haemorrhages 4 Traumatic haemorrhages 5 Bacterial aneurysms 3 Other 4 TOTAL 55 Although not strictly monitored the intraoperative angiogram added an addi- tional forty-fiveto sixty minutes to the pro- cedure (including the time required to place the femoral sheath preoperatively). The four patients with spontaneous intracranial haemorrhage had intra- operative angiography,as their clinicalcon- dition necessitated immediate transfer to theatre for evacuation of the haematoma, precluding preoperative angiography. Intraoperative angiograms were used to 10- calise pseudoaneurysms or arteriovenous fistulae in patients with traumatic haemor- rhages following penetrating head injury. Patients with mycotic aneurysms had intraoperative angiograms to help localise the aneurysms. Intraoperative angiograms were used to monitor the successful surgi- cal closure of carotid cavernous fistulae. Table II: Cases with angiographic findings which altered the surgical procedure PCoAA - posterior communicating artery aneurysm AVM - arteriovenous malformation ASDH - acute subdural haematoma MCAA - middle cerebral artery aneurysm CCF - Carotid-cavernous fistula ICA - Internal carotid artery Patient Pathology Anglographic findings and surgical action 4 R PCoAA Residual neck-clip repositioned 8 L Parietal AVM Residual feeder-removed 11 R Occipital AVM Residual feeder 12 Spontaneous ASDH Intraop angio demonstrated the cause of ASDH- MCAA- clipped 15 R Occipitoparietal AVM Residual feeder-removed 16 LCCF Residual CCF after packing- repacked three times 17 RCCF Residual CCF after packing-repacked 25 Transected vessel Angio showed transected following stab vessel which was then localised and clipped 27 L Occipital AVM Three Intraap angiograms done until complete excision 34 Bacterial aneurysms(3} 4th Aneurysm identified with intraap angio 35 R Occipital AVM Residual feeder-removed 39 Inflammatory MCAA Spontaneous thrombosis of aneurysm shown on intraop angio 40 Spontaneous ICH Intraop angio demonstrated the cause of ICH- MCAA- clipped 50 RICA Aneurysm Non-filling of ICA following clipping - clip repositioned 53 R Paraclinoid Aneurysm Non filling of PCoA following clipping· clip repositioned 55 L Frontal AVM Residual AVM- removed Sixteen of these angiograms revealed findings which altered the surgical proce- dure (TableII) . Six of the patients with AVMs required further surgery to com- pletely excise theA VM. Three of the an- eurysms had to have clipsrepositioned, due to a residual neck in one case and occluded vesselsin two cases.One mycotic aneurysm had thrombosed at the time of surgery.In a second patient with multiple mycotic an- eurysms an additional aneurysm was de- tected on the intraoperative angiogram. Two patients with spontaneous intracerebral haemorrhages were found to have middle cerebral artery aneurysms. This finding enabled immediate clipping. In one of our patients a clip which was 25 SAJOURNAL OF RADIOLOGY. September1996 compromising the lCA was repositioned immediately due to the intraoperative angiogram finding. Discussion In the past, most intraoperative angiography was performed by using fluoroscopy or rapid serial-ftlm angiography, following either direct puncture of the internal ca- rotid or by retrograde catheterisation of the superiidal temporal artery. I Severalauthors have reported the use of a mobile digital subtraction imaging system. I ,2,3 The advan- tages of this system are immediate review of subtracted images, high contrast resolu- tion and superior spatial resolution (although not as good as conventional film lo page 28