J Nearosurg 75:483-485, 1991
Transoral transclival clipping of anterior inferior cerebellar artery aneurysm using new rotating applier Technical note H. ALAN CROCKARD, F.R.C.S., TURGUT KOKSEL, M.D., AND NIGEL WATKIN
Department of Surgical Neurology, National Hospitals for Neurology and Neurosurgery, London, England ~" A large, partly calcified aneurysm buried in the pons and arising from the junction of the basilar artery and the anterior inferior cerebellar artery was successfully occluded using a variangle aneurysm clip with a new rotating pistol-grip applier which allowed transoral access. The authors believe that the new applier, used in association with the current techniques for dural closure, allows for safe transoral surgery for basilar aneurysms. KEY WORDS anterior inferior cerebellar artery 9 aneurysm subaraehnoid hemorrhage 9 maxillotomy 9 instrumentation 9
URGICALaccess to mid-basilar aneurysms is difficult by any route. When approached from both the cerebellopontine angles and the transtentorial suboccipital routes, these aneurysms are obscured by cranial nerves and there is a high risk of morbidity. ~'8'9 Theoretically, the midline transclival approach should provide best access as the vessel and aneurysm lie directly on the dura away from the cranial nerves. This route was investigated and largely abandoned by the masters of aneurysm surgery 20 years ago because of technical difficulties with application and release of the clip and with wound closure and the incidence of postoperative meningitis. 4'~~ New techniques have reduced the risks associated with the last two problems. 2'3 This encouraged us to explore alternative methods of clip delivery and application. We describe the instrumentation and techniques that were successfully used to occlude a large aneurysm at the anterior inferior cerebellar artery (AICA)foasilar junction.
S
Case Report
This 23-year-old male student presented to another hospital with a subarachnoid hemorrhage and the sudden onset of left fourth and sixth nerve palsies. He recovered consciousness rapidly but the cranial nerve deficits persisted. Angiography revealed a large aneurysm at the junction of the basilar artery and the AICA. Computerized tomography showed partial calcification of the aneurysmal sac, which was buried in the sub-
3".Neurosurg. / Volume 75/September, 1991
9 transoral approach
9
stance of the pons and deemed inoperable at the presenting hospital. The patient was transferred to us with a persisting sixth nerve palsy; the fourth nerve weakness had resolved. Repeat angiography confirmed the presence of the lesion and suggested that it had increased in size (Fig. 1 left). In view of the fact that the aneurysm appeared to be buried in the substance of the pons and was inaccessible via conventional posterolateral routes, it was decided to perform transclival transdural surgery. A midline hard and soft palatal split was added to a standard Le Fort maxillotomy, "hinging" laterally on the palatine vessels and nerves in each half of the palate. 6 This allowed exposure of the whole clivus and craniocervical junction down to C-2. The middle portion of the clivus was removed using a high-speed air drill, the dura was opened, and the vertebral arteries and lower two-thirds of the basilar artery were identified. The aneurysm was located deep in the substance of the brain on the left side. Its neck lay posterolaterally behind the origin of a very dominant AICA. On the surface of the brain was the sixth nerve arising from its nucleus, which was judged to be distorted and damaged by the aneurysm. The neck of the aneurysm was occluded with a curved variangle McFadden clip using the rotating pistol-grip aneurysm clip applier* that had been especially * Prototype applier developed with the assistance of Codman UK Ltd., Maidenhead, Berkshire, England.
483
H. A. Crockard, T. Koksel, and N. Watkin
FIG. 1. Left." Preoperative vertebral anglogram showing a large aneurysm at the junction ol the anterior inferior cerebellar and basilar arteries. The lesion is buried in the substance of the brain. A large portion of the aneurysm sac was calcified, as noted on computerized tomography scans (not shown). Right." Postoperative digital subtraction angiogram showing occlusion of the aneurysm. developed for transoral vascular surgery (Fig. 2). The applier shaft has the capability of axial rotation through 360 ~ which, in combination with the varied angle capability of the clip, provides positioning through three axes (Fig. 3). Thus, the applier allowed controlled release of the aneurysm clip, which could be "steered" into position. Several clips were applied and removed until a satisfactory occlusion with preservation of the AICA was obtained and the spring of the clip was entirely intradural (Fig. 1 right). The dural defect was repaired with fascia lata, fat, and a thrombin fibrin glue. The nasopharyngeal mucosa was closed in a layer of interrupted Vicryl sutures.
The maxilla and hard palate were reconstituted as described elsewhere 6 and cerebrospinal fluid (CSF) was drained for 5 clays by means of a lumbar drain. This latter device was converted into a lumboperitoneal shunt at the end of 5 days to maintain a low CSF pressure until the dura was watertight. There was no CSF leak and no meningitis. The patient was able to leave the hospital 8 days after occlusion of the aneurysm. A control angiogram confirmed that the aneurysm was excluded from the circulation. The transoral wounds healed satisfactorily and, at 2 months after surgery, the sixth nerve weakness had almost completely disappeared.
FIG. 2. Left. Drawing of a coronal section showing the use of the pistol-grip applier with rotating barrel which allowed the variangled clip to be "rotated" on the aneurysmal neck while releasing the clip. Right. Enlarged drawing showing rotation of the clip. 484
J. Neurosurg. / Volume 75 / September, 1991
Transclival clipping of an AICA aneurysm
Fit;. 3. The barrel of the applier allows the clip to be rotated through 360~ in one axis. The McFadden clip may be moved through 270~ in another axis. Discussion Aneurysms at the junction of the AICA and the basilar aneurysm are quite rare. Subarachnoid hemorrhage has been a presenting factor in 80% of the cases. Others have manifested with cranial nerve palsies, often involving the seventh and eighth nervesJ 2 Peerless and Drake 9 reported 200 cases of vertebrobasilar arterial aneurysms, and described great difficulty in surgical access to aneurysms located in the lower third of the basilar artery or at the vertebrobasilar junction. Nishimoto, et al.,8 reported difficulty in successfully exposing an aneurysm similar in position to the lesion in this patient; they used a transtentorial suboccipital craniotomy with removal of some of the petrous bone, and their main problem was obstruction of the aneurysm by cranial nerves. Better results with a transpetrosal approach were reported by Kawase, et al.7 All authors have admitted to significant morbidity with their approaches. As our experience with tmnsoral surgery has increased, we have found that meticulous layered closure of the dura combined with a lumbar drain to reduce CSF pressure until there is a watertight closure has allowed extensive intradural surgery without major morbidity or mortality from meningitis.~'3 It was this experience that encouraged us to contemplate a transoral route to the lesion in this case. The conventional aneurysm clip applier is the wrong length and the wrong shape for transoral vascular surgery; the widest part of the instrument's spring handles and the finger positions would lie within the mouth and this hinders release of the clip once applied. The angle of the basilar artery relative to the surgical access and the limited surgical "window" through the clivus suggested the use of the pistol-grip mechanism with a rotating barrel that would allow a "variangle" insertion of the clip. By this means, the clip could be carefully rotated onto the aneurysmal neck with one hand while the other controlled its release through the pistol grip (Fig. 2). The instrument was sufficiently long (21 cm) to prevent the applying hand from being impeded by the mouth or the transoral retracting instruments; the hand could also be steadied to compensate for the increased instrument length. There was no difficulty in readjusting the clip's position after application. The Ya~argil aneurysm clip applier is also a pistol-grip instrument but is too short and has no "variangie" facility; in addition, the barrel cannot be rotated when the clip J. Neurosurg. / Volume 75/September, 1991
jaws are open. Thus, it cannot be "steered" into final position. We would recommend the transoral approach for aneurysms arising in the mid and lower thirds of the basilar artery, particularly those buried in the substance of the brain. The route is not unduly hazardous, provided that care is taken with dural closure. We believe that the prototype pistol grip applier has a useful place in the surgical armamentarium for these difficult aneurysms. We believe that the instrument and the steering technique should also be considered for anterior circle aneurysms. Acknowledgments We thank Barbara Hyams for preparing the illustrations and Michelle Green for preparation of the manuscript. References 1. Croekard HA: The transmaxillary approach to the clivus, in Sekhar LN, Janecka IP (eds): Surgery of Cranial Base Tumours: A Colour Atlas. New York: Raven Press (In press, 1991) 2. Crockard HA: The transoral approach to the base of the brain and upper cervical cord. Ann R Coil Surg Engl 67: 321-325, 1985 3. Crockard HA, Sen CN: The transoral approach for the management of intradural lesions at the craniovertebral junction: review of 7 cases. Nenrosurgery 28:88-98, 1991 4. Drake CG: The surgical treatment of vertebral-basilar aneurysms. Clin Neurosurg 16:114-169, 1969 5. Drake CG: The treatment of aneurysms of the posterior circulation. Clin Neurosurg 26:96-144, 1978 6. James D, Crockard HA: Surgical access to the base of the skull and upper cervical spine by an extended maxillotomy. Neurosnrgery (In press, 1991) 7. Kawase T, Toya S, Shiobara R, et al: Transpetrosal approach for aneurysms of the lower basilar artery. J Neurosurg 63:857-861, 1985 8. Nishimoto A, Fujimoto S, Tsuchimoto S, et al: Anterior inferior cerebellar artery aneurysm. Report of three cases. J Neurosurg 59:697-702, 1983 9. Peerless SJ, Drake CG: Surgical techniques of posterior cerebral aneurysms, in Schmidek HH, Sweet WH (eds): Operative Neurosurgical Techniques. Indications, Methods, and Results. New York: Grune & Stratton, 1982, Voi 2, pp 909-931 10. Pia HW: Classification and treatment of aneurysms of the vertebrobasilar system. Neurol Med Chir 19: 574-594, 1979 11. Sano K, Jinbo M, Saito I: [Vertebro-basilar aneurysms, with special reference to the transpharyngeal approach to basilar artery aneurysm.] No To Shinkei 18:1197-1203, 1966 (Jpn) 12. Schwartz HG: Arterial aneurysm of the posterior fossa. J Neurosurg 5:312-316, 1948 Manuscript received July 2, 1990. Accepted in final form April 11, 1991. Dr. Koksel was a visiting Research Fellow from Gulhane Military Medical Faculty, Ankara, Turkey. Address reprint requests to: H. Alan Crockard, F.R.C.S., Department of Surgical Neurology, National Hospitals for Neurology and Neurosurgery, Queen Square, London WC 1N 3BG, England. 485
Transoral transclival clipping of anterior inferior cerebellar artery aneurysm using new rotating applier Technical note H. ALAN CROCKARD, F.R.C.S., TURGUT KOKSEL, M.D., AND NIGEL WATKIN
Department of Surgical Neurology, National Hospitals for Neurology and Neurosurgery, London, England ~" A large, partly calcified aneurysm buried in the pons and arising from the junction of the basilar artery and the anterior inferior cerebellar artery was successfully occluded using a variangle aneurysm clip with a new rotating pistol-grip applier which allowed transoral access. The authors believe that the new applier, used in association with the current techniques for dural closure, allows for safe transoral surgery for basilar aneurysms. KEY WORDS anterior inferior cerebellar artery 9 aneurysm subaraehnoid hemorrhage 9 maxillotomy 9 instrumentation 9
URGICALaccess to mid-basilar aneurysms is difficult by any route. When approached from both the cerebellopontine angles and the transtentorial suboccipital routes, these aneurysms are obscured by cranial nerves and there is a high risk of morbidity. ~'8'9 Theoretically, the midline transclival approach should provide best access as the vessel and aneurysm lie directly on the dura away from the cranial nerves. This route was investigated and largely abandoned by the masters of aneurysm surgery 20 years ago because of technical difficulties with application and release of the clip and with wound closure and the incidence of postoperative meningitis. 4'~~ New techniques have reduced the risks associated with the last two problems. 2'3 This encouraged us to explore alternative methods of clip delivery and application. We describe the instrumentation and techniques that were successfully used to occlude a large aneurysm at the anterior inferior cerebellar artery (AICA)foasilar junction.
S
Case Report
This 23-year-old male student presented to another hospital with a subarachnoid hemorrhage and the sudden onset of left fourth and sixth nerve palsies. He recovered consciousness rapidly but the cranial nerve deficits persisted. Angiography revealed a large aneurysm at the junction of the basilar artery and the AICA. Computerized tomography showed partial calcification of the aneurysmal sac, which was buried in the sub-
3".Neurosurg. / Volume 75/September, 1991
9 transoral approach
9
stance of the pons and deemed inoperable at the presenting hospital. The patient was transferred to us with a persisting sixth nerve palsy; the fourth nerve weakness had resolved. Repeat angiography confirmed the presence of the lesion and suggested that it had increased in size (Fig. 1 left). In view of the fact that the aneurysm appeared to be buried in the substance of the pons and was inaccessible via conventional posterolateral routes, it was decided to perform transclival transdural surgery. A midline hard and soft palatal split was added to a standard Le Fort maxillotomy, "hinging" laterally on the palatine vessels and nerves in each half of the palate. 6 This allowed exposure of the whole clivus and craniocervical junction down to C-2. The middle portion of the clivus was removed using a high-speed air drill, the dura was opened, and the vertebral arteries and lower two-thirds of the basilar artery were identified. The aneurysm was located deep in the substance of the brain on the left side. Its neck lay posterolaterally behind the origin of a very dominant AICA. On the surface of the brain was the sixth nerve arising from its nucleus, which was judged to be distorted and damaged by the aneurysm. The neck of the aneurysm was occluded with a curved variangle McFadden clip using the rotating pistol-grip aneurysm clip applier* that had been especially * Prototype applier developed with the assistance of Codman UK Ltd., Maidenhead, Berkshire, England.
483
H. A. Crockard, T. Koksel, and N. Watkin
FIG. 1. Left." Preoperative vertebral anglogram showing a large aneurysm at the junction ol the anterior inferior cerebellar and basilar arteries. The lesion is buried in the substance of the brain. A large portion of the aneurysm sac was calcified, as noted on computerized tomography scans (not shown). Right." Postoperative digital subtraction angiogram showing occlusion of the aneurysm. developed for transoral vascular surgery (Fig. 2). The applier shaft has the capability of axial rotation through 360 ~ which, in combination with the varied angle capability of the clip, provides positioning through three axes (Fig. 3). Thus, the applier allowed controlled release of the aneurysm clip, which could be "steered" into position. Several clips were applied and removed until a satisfactory occlusion with preservation of the AICA was obtained and the spring of the clip was entirely intradural (Fig. 1 right). The dural defect was repaired with fascia lata, fat, and a thrombin fibrin glue. The nasopharyngeal mucosa was closed in a layer of interrupted Vicryl sutures.
The maxilla and hard palate were reconstituted as described elsewhere 6 and cerebrospinal fluid (CSF) was drained for 5 clays by means of a lumbar drain. This latter device was converted into a lumboperitoneal shunt at the end of 5 days to maintain a low CSF pressure until the dura was watertight. There was no CSF leak and no meningitis. The patient was able to leave the hospital 8 days after occlusion of the aneurysm. A control angiogram confirmed that the aneurysm was excluded from the circulation. The transoral wounds healed satisfactorily and, at 2 months after surgery, the sixth nerve weakness had almost completely disappeared.
FIG. 2. Left. Drawing of a coronal section showing the use of the pistol-grip applier with rotating barrel which allowed the variangled clip to be "rotated" on the aneurysmal neck while releasing the clip. Right. Enlarged drawing showing rotation of the clip. 484
J. Neurosurg. / Volume 75 / September, 1991
Transclival clipping of an AICA aneurysm
Fit;. 3. The barrel of the applier allows the clip to be rotated through 360~ in one axis. The McFadden clip may be moved through 270~ in another axis. Discussion Aneurysms at the junction of the AICA and the basilar aneurysm are quite rare. Subarachnoid hemorrhage has been a presenting factor in 80% of the cases. Others have manifested with cranial nerve palsies, often involving the seventh and eighth nervesJ 2 Peerless and Drake 9 reported 200 cases of vertebrobasilar arterial aneurysms, and described great difficulty in surgical access to aneurysms located in the lower third of the basilar artery or at the vertebrobasilar junction. Nishimoto, et al.,8 reported difficulty in successfully exposing an aneurysm similar in position to the lesion in this patient; they used a transtentorial suboccipital craniotomy with removal of some of the petrous bone, and their main problem was obstruction of the aneurysm by cranial nerves. Better results with a transpetrosal approach were reported by Kawase, et al.7 All authors have admitted to significant morbidity with their approaches. As our experience with tmnsoral surgery has increased, we have found that meticulous layered closure of the dura combined with a lumbar drain to reduce CSF pressure until there is a watertight closure has allowed extensive intradural surgery without major morbidity or mortality from meningitis.~'3 It was this experience that encouraged us to contemplate a transoral route to the lesion in this case. The conventional aneurysm clip applier is the wrong length and the wrong shape for transoral vascular surgery; the widest part of the instrument's spring handles and the finger positions would lie within the mouth and this hinders release of the clip once applied. The angle of the basilar artery relative to the surgical access and the limited surgical "window" through the clivus suggested the use of the pistol-grip mechanism with a rotating barrel that would allow a "variangle" insertion of the clip. By this means, the clip could be carefully rotated onto the aneurysmal neck with one hand while the other controlled its release through the pistol grip (Fig. 2). The instrument was sufficiently long (21 cm) to prevent the applying hand from being impeded by the mouth or the transoral retracting instruments; the hand could also be steadied to compensate for the increased instrument length. There was no difficulty in readjusting the clip's position after application. The Ya~argil aneurysm clip applier is also a pistol-grip instrument but is too short and has no "variangie" facility; in addition, the barrel cannot be rotated when the clip J. Neurosurg. / Volume 75/September, 1991
jaws are open. Thus, it cannot be "steered" into final position. We would recommend the transoral approach for aneurysms arising in the mid and lower thirds of the basilar artery, particularly those buried in the substance of the brain. The route is not unduly hazardous, provided that care is taken with dural closure. We believe that the prototype pistol grip applier has a useful place in the surgical armamentarium for these difficult aneurysms. We believe that the instrument and the steering technique should also be considered for anterior circle aneurysms. Acknowledgments We thank Barbara Hyams for preparing the illustrations and Michelle Green for preparation of the manuscript. References 1. Croekard HA: The transmaxillary approach to the clivus, in Sekhar LN, Janecka IP (eds): Surgery of Cranial Base Tumours: A Colour Atlas. New York: Raven Press (In press, 1991) 2. Crockard HA: The transoral approach to the base of the brain and upper cervical cord. Ann R Coil Surg Engl 67: 321-325, 1985 3. Crockard HA, Sen CN: The transoral approach for the management of intradural lesions at the craniovertebral junction: review of 7 cases. Nenrosurgery 28:88-98, 1991 4. Drake CG: The surgical treatment of vertebral-basilar aneurysms. Clin Neurosurg 16:114-169, 1969 5. Drake CG: The treatment of aneurysms of the posterior circulation. Clin Neurosurg 26:96-144, 1978 6. James D, Crockard HA: Surgical access to the base of the skull and upper cervical spine by an extended maxillotomy. Neurosnrgery (In press, 1991) 7. Kawase T, Toya S, Shiobara R, et al: Transpetrosal approach for aneurysms of the lower basilar artery. J Neurosurg 63:857-861, 1985 8. Nishimoto A, Fujimoto S, Tsuchimoto S, et al: Anterior inferior cerebellar artery aneurysm. Report of three cases. J Neurosurg 59:697-702, 1983 9. Peerless SJ, Drake CG: Surgical techniques of posterior cerebral aneurysms, in Schmidek HH, Sweet WH (eds): Operative Neurosurgical Techniques. Indications, Methods, and Results. New York: Grune & Stratton, 1982, Voi 2, pp 909-931 10. Pia HW: Classification and treatment of aneurysms of the vertebrobasilar system. Neurol Med Chir 19: 574-594, 1979 11. Sano K, Jinbo M, Saito I: [Vertebro-basilar aneurysms, with special reference to the transpharyngeal approach to basilar artery aneurysm.] No To Shinkei 18:1197-1203, 1966 (Jpn) 12. Schwartz HG: Arterial aneurysm of the posterior fossa. J Neurosurg 5:312-316, 1948 Manuscript received July 2, 1990. Accepted in final form April 11, 1991. Dr. Koksel was a visiting Research Fellow from Gulhane Military Medical Faculty, Ankara, Turkey. Address reprint requests to: H. Alan Crockard, F.R.C.S., Department of Surgical Neurology, National Hospitals for Neurology and Neurosurgery, Queen Square, London WC 1N 3BG, England. 485
