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Biomedical subjects

R F Spetzler

Publications and source records attributed to R F Spetzler.

At least 91 records · Page 5Linked to original sources

Secondary craniofacial problems following skull base surgery.

Skull base wounds remain the most challenging that a skull base surgeon faces because of the unique and unforgiving requirements of the intracranial compartment. To successfully reconstruct these defects after complex exposure and radical resection around vital structures, a most conservative approach must be taken (i.e., one must choose the option that has the greatest chance to be successful, even if it means taking the extra time and effort of doing a free tissue transfer). Indeed, one can take no short cuts if the skull base would be left with a tenuous repair. Close postoperative surveillance of the patient for complications and maximal medical management is essential. Because of the difficulty of examining the hidden skull base wound postoperatively, surgeons must have a low threshold for re-exploration if a complication is suspected. As the first decade of the multidisciplinary skull base team approach passes, and long-term results are being assessed, the question of "is it worth it?" is fair. The reported series are showing increased survival rates and decreased complication rates. Therefore, the answer would appear to be "yes". The question is best answered, however, by the individual patient who previously had no hope for treatment of his or her deep-seated skull base tumor.

Adult↗

Internal carotid artery sacrifice for radical resection of skull base tumors.

When dealing with skull base tumors that encase the internal carotid artery (ICA), the surgeon must decide between ICA preservation and incomplete tumor resection, or radical resection with ICA sacrifice. In our experience with more than 300 anterior skull base tumors, the ICA was sacrificed in only 10 patients. These tumors were malignant, except for one meningioma that occluded the ICA and produced translent ischemic symptoms. All patients had the ICA resected with the tumor, and all patients underwent revascularization (cervical ICA-MCA saphenous bypass, n = 4; cervical-to-supraclinoid bypass, n = 1; petrous-to-supraclinoid bypass, n = 3; bonnet bypass, n = 2). This small patient series reflects our practice of preserving the ICA whenever possible. We recommend preserving the ICA with benign tumors because they do not invade the artery, or do so only to a limited extent. In addition, similar rates of tumor recurrence are seen after aggressive resection with or without ICA sacrifice. In contrast, we recommend radical tumor resection and sacrifice of the ICA with malignant tumors because they directly threaten the integrity of the ICA and the patient's survival. The ICA should not be considered a limitation to radical tumor resection because the ICA can be reconstructed safely with an appropriate bypass procedure.

Journal Article↗

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization.

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

Accidents, Traffic↗

Revascularization and aneurysm surgery: current techniques, indications, and outcome.

Revascularization is an important component of treatment for complex aneurysms that cannot be directly clipped and instead require parent vessel occlusion. A consecutive series of 61 patients with 63 aneurysms requiring cerebral revascularization is presented. Aneurysms were located along the petrous internal carotid artery (ICA) (n = 5), the cavernous ICA (n = 16), the supraclinoid ICA (n = 12), the middle cerebral artery (n = 17), the anterior cerebral artery (n = 4), the vertebral artery/posterior inferior cerebellar artery (n = 5), and the midbasilar artery (n = 4). Aneurysms were treated by direct clipping (n = 8), trapping (n = 28), proximal vessel occlusion (n = 9), distal vessel occlusion (n = 1), excision (n = 15), and thrombotic occlusion (n = 2). Revascularization was performed with petrous to supraclinoid ICA bypass (n = 12), superficial temporal artery to middle cerebral artery bypass (n = 15), superficial temporal artery to middle cerebral artery bypass with saphenous graft (n = 5), superficial temporal artery to superior cerebellar artery bypass (n = 4) long saphenous bypass (n = 11), in situ bypass (n = 3), and primary reanastomosis (n = 13). Fifty-seven patients (93%) had good outcomes, and one patient died (surgical mortality, 2%). This experience demonstrates that revascularization can be performed with low morbidity and mortality. We think that the cumulative risks of not performing revascularization in patients who tolerate ICA balloon occlusion exceed the surgical risk of revascularization. We therefore favor revascularization in patients with complex aneurysms treated by surgical arterial occlusion.

Adolescent↗

Intra-aortic balloon pump counterpulsation in the management of concomitant cerebral vasospasm and cardiac failure after subarachnoid hemorrhage: technical case report.

We report two patients who had symptomatic cerebral vasospasm and cardiac failure after aneurysmal subarachnoid hemorrhage and who were treated successfully with intra-aortic balloon pump counterpulsation therapy. Both patients developed congestive heart failure and pulmonary edema while receiving postoperative hypertensive, hypervolemic, hemodilutional (Triple-H) therapy for symptomatic cerebral vasospasm. Both cases of cardiac failure were refractory to maximum pressor and inotropic infusions. Intra-aortic balloon pump counterpulsation was used to optimize cardiac performance to allow continuation of Triple-H therapy and to maintain adequate cerebral perfusion in an attempt to decrease the risk of cerebral ischemic complications. Both patients have had good long-term outcomes. These two cases illustrate the potential usefulness of the intra-aortic balloon pump as an adjunct to Triple-H therapy in patients with symptomatic cerebral vasospasm and cardiac failure. To our knowledge, this report documents the first clinical application of this adjunctive therapy for vasospasm after aneurysmal subarachnoid hemorrhage.

Aged↗

Titanium aneurysm clips: Part I--Mechanical, radiological, and biocompatibility testing.

Most aneurysm clips are made of cobalt-based alloys. Although these clips are nonferromagnetic, they still produce artifact that degrades the quality of magnetic resonance (MR) images. A new aneurysm clip of pure titanium was developed to minimize artifact on postoperative MR images. We evaluated these clips in a series of mechanical tests in vitro, biocompatibility tests in rabbits, and radiological tests in greyhound dogs. The clip sizes and shapes matched those of conventional aneurysm clips. The average closing forces ranged between 151.6 and 181.8 g and were not diminished by repeated sterilization or stress. After > 20 million cycles of high-pressure and high-frequency pulsations, the clips did not open and the closing forces were not reduced. Titanium aneurysm clips implanted in the subarachnoid space of 12 rabbits for 1 or 6 months produced mild gliosis identical to that produced by implantation of cobalt alloy clips in 12 control rabbits. Based on pre- and postoperative weights and electron microscopic scans, the titanium implants did not corrode. The artifact on computed tomographic and MR imaging produced by a titanium clip placed on the internal carotid artery of a greyhound was less than that produced by an identical cobalt-chrome alloy clip by a factor of two to three. This study demonstrated that titanium aneurysm clips are mechanically equivalent to conventional clips, biocompatible, and corrosion resistant. Furthermore, titanium clips have superior imaging characteristics, creating less computed tomographic and MR imaging artifact and permitting better resolution of anatomic structures than cobalt alloy clips.

Animals↗

Titanium aneurysm clips: Part II--Seizure and electroencephalographic studies in implanted rabbits.

Because titanium is widely used in neurosurgical procedures, we compared spontaneous and induced epileptiform activity in 12 rabbits with titanium clips implanted in the subarachnoid space with 12 rabbits with cobalt alloy clips and 6 rabbits that were not operated on that served as controls. Beginning 1 week after surgery, 30-minute electroencephalographic recordings were made at monthly intervals for 6 months. Recordings were scored by an electroencephalographer unaware of which treatment group was being recorded. In 48 recordings made during 6 months, no epileptiform activity was observed in any animal. Seizure threshold was evaluated by continuous intravenous injection of the convulsant drug, pentylenetetrazole (2 mg/kg/min), with continuous electroencephalographic recording. Time to spiking for the nonsurgical control group was 327 mean seconds +/- 181 standard deviation (SD), 216 mean seconds +/- 135 SD for the titanium group, and 389 mean seconds +/- 290 SD for the cobalt group. There were no significant differences among the groups (P = 0.17). Latency to behavioral tonicoclonic seizure was 1031 seconds +/- 537 SD for the group not operated on, 875 seconds +/- 334 SD for the titanium group, and 1267 seconds +/- 764 SD for the cobalt group. This study suggests that titanium clips are well tolerated within the brain and will not induce seizures.

Animals↗

Titanium aneurysm clips: Part III--Clinical application in 16 patients with subarachnoid hemorrhage.

This report describes the first clinical use of newly developed titanium clips in the treatment of 16 patients with subarachnoid hemorrhage. There were no immediate or delayed complications related to the titanium clips. Thirteen patients had good outcomes, and one patient had moderate disabilities (mean follow-up, 5.4 mo). Two patients with Hunt and Hess Grade IV hemorrhages died postoperatively. The average cross-sectional areas of clip artifact on postoperative magnetic resonance imaging studies was 0.96, 1.36, and 1.05 cm2 on T1-, T2-, and intermediate-weighted images, respectively. In comparison, a matched control group with cobalt alloy clips had average cross-sectional areas of 3.13, 3.70, and 2.81 cm2 on T1-, T2-, and intermediate-weighted images, respectively. The average artifact volumes on gradient echo magnetic resonance images for titanium and cobalt alloy clips were 1.8 and 10.1 cm3, respectively. In addition, the gap on magnetic resonance imaging angiograms from clip artifacts was 0.9 cm with titanium and 2.6 cm with cobalt alloy clips. In conclusion, titanium aneurysm clips seem to be safe and effective and seem to reduce clip artifacts on magnetic resonance imaging threefold, compared with commercially available cobalt alloy clips. Because of this important advantage over conventional clips, titanium clips should be considered for routine use in aneurysm surgery.

Adult↗

The contralateral transcallosal approach: experience with 32 patients.

OBJECTIVE: To demonstrate the usefulness of the contralateral transcallosal approach for resecting lesions located laterally in or adjacent to the lateral ventricle. METHODS: Modifications to the standard ipsilateral transcallosal technique include positioning the head with the midline oriented horizontally, placing the side with the lesion up, and performing the craniotomy and interhemispheric dissection on the contralateral side. This approach avoids a transcortical incision, allows gravity to hold open the interhemispheric fissure, and increases the lateral exposure of the lesion. This approach was used in 32 patients with a variety of lesions, including 6 cavernous malformations, 7 arteriovenous malformations, and 19 tumors of various types. All but three lesions were located on the left side. RESULTS: All six cavernous malformations, all four benign tumors, and four of the seven arteriovenous malformations were resected completely. Malignant tumors were resected subtotally, and three arteriovenous malformations required stereotactic radiosurgery to treat residual deep nidus. There was no surgical mortality. Two patients experienced neurological deterioration. CONCLUSION: The contralateral transcallosal approach can be used to treat a variety of lesions safely and successfully.

Adolescent↗

Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms.

Dolichoectatic and fusiform aneurysms represent a small subset of cerebral aneurysms and are often among the most difficult to treat. A consecutive series of 40 patients with 41 of these two types of aneurysms is presented, including their clinical characteristics and surgical treatments. Common to all aneurysms was the pathological involvement of a length of blood vessel with separate inflow and outflow sites (nonsaccular). However, dolichoectatic aneurysms have markedly different symptoms and surgical treatments depending on their location in either the anterior or posterior circulation. Anterior circulation aneurysms involved the petrous internal carotid artery (ICA) in one, the supraclinoid ICA in three, the middle cerebral artery in 13, and the anterior cerebral artery in four patients. Posterior circulation aneurysms involved the basilar artery in 13, the vertebral artery in six, and the posterior inferior cerebellar artery in one patient. Various surgical procedures were performed, including direct clipping, trapping with bypass, proximal occlusion, resection with reanastomosis, transposition, aneurysmorrhaphy with thrombectomy, and wrapping. There was no surgical mortality in the patient series, and treatment was effective in many patients. Overall, outcome at late follow up was good (Glasgow Outcome Scale scores 1-2) in 78% of patients. Patients with anterior circulation aneurysms had better outcomes than patients with posterior circulation aneurysms, with good outcomes in 90% and 65% of the cases, respectively. Dolichoectatic and giant serpentine aneurysms may develop from smaller fusiform aneurysms and represent a spectrum of the same pathological entity. Arterial dissection may also play a role in the initial development of these aneurysms.

Adolescent↗

Skull base tumors. A critical appraisal and clinical series employing image guidance.

Two of the most significant developments in neurosurgery over the past ten years have been the application of intraoperative navigational units and the widespread use of "skull base" surgical techniques. These developments have independently revolutionized the way in which neurosurgeons approach intracranial pathology. The combination of these two developments has had a profound effect in our clinical practice to improve outcome and extend our capabilities. This ability to see around the corner, "x-ray" vision as some have called it, provides an added measure of safety for the patient while allowing the surgeon to treat the lesion in a more aggressive fashion.

Adolescent↗

Carotid endartectomy.

This article provides an in-depth review of carotid endarterectomy for the treatment of occlusive carotid disease. Topics range from preoperative diagnostic assessment to postoperative complications. Key issues related to operative management, including anesthetic technique, intraoperative monitoring, cerebral protection, anticoagulation therapy, and intraluminal shunting, are emphasized. Operative techniques are discussed and illustrated in detail.

Anesthesia, General↗

The far lateral-combined supra- and infratentorial approach: clinical experience.

Four patients underwent a far lateral-combined craniotomy procedure for extensive tumors of the clivus and craniocervical junction. Their presentation, operative, and clinical course are discussed. All patients had improved at their follow-up examination (mean follow-up, 10.7 months). This approach can now be applied to extensive tumors of the petroclival region and craniocervical junction to decrease morbidity.

Adult↗