James I. Ausman and Guy Owens
Donald L. Erickson, James I. Ausman and Shelley N. Chou
✓ Before the advent of microsurgery for acoustic tumors, it was accepted that the majority of seventh nerves would be lost during the removal of large tumors. It is now possible to preserve these attenuated seventh nerves, even with very large tumors. Postoperative facial palsy may be present even with an anatomically intact seventh nerve, but our experience has demonstrated that recovery will ultimately occur. Eight of our nine patients with this situation have regained facial function, although in some the first clinical evidence of recovery did not occur for 1 year.
James I. Ausman and Ronald P. Pawl
There will be major scientific advances and socioeconomic changes in the 21st century that will influence the development of medicine and neurosurgery. These changes will affect those in academic medical centers and the private practitioners of medicine and neurosurgery. Neurosurgeons' philosophy and practice methods must adapt to these trends. Because of the continuing growth in scientific knowledge and the rapid spread of communications of all types, physicians will best work in groups and teams. These group forces will require the physicians to surrender some independence to gain the power of the integrated knowledge and political and social force of a group. Graduate and postgraduate education programs will also change to adapt to these new realities. Those who understand these new shifts will be the most successful in establishing and conducting practices in academic centers and private practice.
James I. Ausman, James Moore and Shelley N. Chou
✓ The authors report a case with spontaneous revascularization of the brain after surgical anastomosis of the superficial temporal artery to the middle cerebral artery.
A detailed analysis of multiple pre- and postoperative angiograms in 40 consecutive patients
Richard E. Latchaw, James I. Ausman and Myoung C. Lee
✓ Pre- and postoperative angiograms on 40 patients undergoing superficial temporal-middle cerebral artery (STA-MCA) bypass surgery have been examined in detail. Multiple postoperative angiograms have been obtained to evaluate the change in both the bypass circuit and the intracranial circulation over time. A reproducible system for evaluating the degree of intracranial vascular filling via the bypass is introduced.
The study shows that the STA and its anastomotic branch increase in size over time, measured in months, in the majority of patients. This is paralleled by a progressive increase in the degree of intracranial vascular filling. These changes are proportional to the severity of the vascular disease before surgery. The pattern of preoperative collateral circulation may change over time following the addition of the bypass circuit. The progressive change over time suggests that a static analysis at one time may belie the true effect of the surgery. The change of collateral circulation, with augmentation of blood supply to areas of the brain other than those affected by the recent ischemic event, means that a total cerebral evaluation including neuropsychological testing may be necessary for adequate evaluation of the effect of the bypass surgery.
Fernando G. Diaz, Sam Ohaegbulam, Manuel Dujovny and James I. Ausman
✓ Direct surgery on aneurysms in the cavernous sinus is a formidable technical procedure. The intimate relationship of the intracavernous carotid artery to the venous structures and to the cranial nerves make surgical access difficult at best. Thirty-two of 356 aneurysm patients presented with symptomatic aneurysms originating from the intracavernous internal carotid artery. Twenty-one patients had aneurysms contained entirely within the cavernous sinus, and in 11 others the aneurysms arose within the cavernous sinus and extended into the subarachnoid space. Of the purely intracavernous aneurysms there were five small aneurysms (< 25 mm) and 16 giant (≥ 25 mm) aneurysms. Fifteen patients with purely intracavernous lesions had a superior orbital fissure syndrome, and six had a variety of other symptoms. Of 11 patients with subarachnoid extension, five had a subarachnoid hemorrhage (Grade I or II), five had ipsilateral visual loss, and one had periorbital pain. The aneurysms were treated as follows: Group 1 received progressive ligation of the internal carotid artery in the neck with a Selverstone clamp and a surface superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis (purely intracavernous in nine, and with subarachnoid extension in one); Group 2 underwent trapping of the internal carotid artery and a deep STA-MCA anastomosis (purely intracavernous in seven); and Group 3 had direct clipping of the aneurysm (purely intracavernous in five, and with subarachnoid extension in 10).
The cavernous sinus was entered directly through its roof by a pterional craniotomy with radical removal of the optic canal, lesser sphenoid wing, and lateral and superior orbital walls. Proximal control of the internal carotid artery was obtained through a cervical incision. Two patients in Group 1 developed transient neurological deficits, which resolved. Two patients in Group 2 developed a cerebral infarction, one of whom died; in both of these patients, the anastomosis was completed after the internal carotid artery occlusion. Two patients in Group 3 progressed from marked visual loss to blindness of the same side, and one developed an intraventricular hemorrhage during induction of anesthesia and died without surgery. It is proposed that a direct approach to symptomatic aneurysms in the cavernous sinus is the best initial alternative. When this approach is not feasible, a trapping procedure preceded by a high-flow extracranial-intracranial anastomosis may be considered. Although the authors have been able to clip aneurysms of various sizes, this has not been possible in all patients. Further work is needed in this area.
James I. Ausman, Fernando G. Diaz, Dante F. Vacca and Balaji Sadasivan
✓ Eighty-three patients underwent 85 intracranial to extracranial pedicle bypass anastomosis procedures to the posterior circulation. There were 15 patients with occipital artery (OA) to posterior inferior cerebellar artery (PICA) anastomosis, 20 patients with OA to anterior inferior cerebellar artery (AICA) anastomosis, and 50 patients with superficial temporal artery (STA) to superior cerebellar artery (SCA) anastomosis. All patients had transient ischemic attacks (TIA's) suggestive of vertebrobasilar ischemia. Twenty-seven patients had crescendo TIA's or stroke in evolution and were considered to be clinically unstable. All patients had severe bilateral distal vertebral artery or basilar artery disease. Twenty-two patients had bilateral vertebral artery occlusion and three had basilar artery occlusion. In this series, 69% had complete resolution of symptoms; the mortality rate was 8.4% and the morbidity rate 13.3%. Clinically stable patients did better than unstable patients. The STA-SCA anastomosis was well tolerated and technically less demanding than the OA-PICA or OA-AICA anastomosis procedures. Patients with symptomatic severe bilateral vertebral or basilar artery disease have a grave prognosis and the option of a surgical arterial pedicle revascularization procedure should be offered to them.
Asim Mahmood, Manuel Dujovny, Maximo Torche, Ljubisa Dragovic and James I. Ausman
✓ The foramen caecum (FC) is a triangular-shaped fossa situated in the midline on the base of the brain stem, at the pontomedullary junction. Although this area is known to have a very high concentration of brainstem perforating vessels, its microvascular anatomy has not been studied in detail. The purpose of this study was to detail the microvasculature of this territory. Twenty unfixed brains were injected with silicone rubber solution and dissected under a microscope equipped with a camera. The origin, course, outer diameter, and branching pattern of the perforators were examined.
The total number of perforators found in the 20 brains was 287, with an average (± standard deviation) of 14.35 ± 1.24 perforators per brain (range seven to 28). Their origin was as follows: right vertebral artery in 52 perforators (18.11%); left vertebral artery in 35 (12.19%); basilar artery below the anterior inferior cerebellar artery (AICA) in 139 (48.43%); basilar artery above the AICA in 46 (16.02%); AICA in 10 (3.48%); and anterior spinal artery in five (1.74%). Most of the perforators arose as sub-branches of larger trunks; their average outer diameter was 0.16 ± 0.006 mm while that of trunks was 0.35 ± 0.02 mm.
These anatomical data are important for those wishing 1) to study the pathophysiology of vascular insults to this area caused by atheromas, thrombi, and emboli; 2) to plan vertebrobasilar aneurysm surgery; 3) to plan surgery for vertebrobasilar insufficiency; and 4) to study foramen magnum neoplasms.