Faculty Bibliography

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

STUDY DESIGN: In a clinical retrospective study, the authors review long-term results of occipitocervical fusion using a wide diameter, contoured, threaded Steinmann pin. OBJECTIVES: To evaluate the clinical and radiographic results of occipitocervical fusion using this technique in a variety of abnormalities including rheumatoid arthritis. SUMMARY OF BACKGROUND DATA. The various surgical techniques and hardware developed for occipitocervical fusion have been associated with mixed results, particularly in patients with rheumatoid arthritis or basilar invagination. METHODS: Thirty-nine patients with occipitocervical instability were internally fixed with a wide diameter, contoured, threaded Steinmann pin wired to the occiput and cervical laminae or facets. Fusion was facilitated using autologous iliac crest bone graft and a cervical orthosis. Instability resulted from rheumatoid arthritis (n = 12), congenital anomalies (n = 12), trauma (n = 10), tumor (n = 4), or osteogenesis imperfecta (n = 1). Fifteen patients had radiographic evidence of basilar invagination. Long-term outcome (mean follow-up period, 38.9 months; range, 12-78 months) was based on clinical and radiographic review. RESULTS: Thirty-seven patients (97%) had a stable postoperative occipitocervical construct: there were 35 osseous unions, two fibrous unions, and one nonunion. There was on postoperative death from pulmonary complications. No patient developed evidence of new, recurrent, or progressive basilar invagination. CONCLUSION: The authors concluded that rigid segmental fixation of the craniovertebral junction using a wide diameter, contoured, threaded Steinmann pin and supplemental autograft creates excellent fusion with minimal complications. This technique is appropriate for a variety of abnormalities including rheumatoid arthritis

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

The viewing wand is a frameless stereotactic arm that can be used in conjunction with computerized tomography (CT) or magnetic resonance (MR) imaging to provide image-based intraoperative navigation. The authors report a series of 325 cases in which the viewing wand was used and evaluated for its utility, ease of integration into the standard surgical setup, reliability, and real-world accuracy. The use of the system was associated with minimal additional effort or time spent in setting up the procedure as long as a trained technician performed the data transfer and reconstruction. The viewing wand was used in 165 cases in conjunction with CT and 145 cases with MR imaging. The system was reliable, achieving a useful registration in 310 of 325 cases (95.4%). Fiducial-based registration was more accurate than an anatomical landmark-surface fit algorithm method of registration (mean 2.8 vs. 5.6 mm error, respectively, for CT; and mean 3.0 vs. 6.2 mm for MR imaging). The actual error of the system in estimating the position of the probe tip just after registration was judged by the operating surgeon to be less than 2 mm in 92% of MR imaging cases and in 82% of CT cases, between 2 and 5 mm in 7% of MR imaging and 17% of CT cases, and greater than 5 mm in less than 1% of MR imaging and 1.2% of CT cases. The accuracy of the system degraded during the operation, so that by the third evaluation the error was estimated to be less than 2 mm in 77% of MR imaging and 62% of CT cases. Overall, the viewing wand was found to be reliable and accurate. This real-world accuracy was sufficient for a broad range of applications including glioma resection, cerebrospinal fluid shunting procedures, resection of small subcortical masses, and temporal lobe resection. The system is a useful navigational aid that allows a direct approach to intracranial pathology without the drawbacks of application and the limitations of a stereotactic frame

METHODS. Vertebral artery injury is a rarely described complication of anterior cervical decompression. The authors performed a retrospective review of their operative database for the purposes of defining the optimal management of this complication and its avoidance. RESULTS. Four of 1,215 (0.3%) patients undergoing anterior cervical operation sustained arterial injuries. In three cases, primary repair of the artery was successful; in one case, the artery was exposed and ligated. There were no postoperative ischemic complications. Artery laceration occurred during decompression (n = 2), screw tapping (n = 1), and during soft tissue retraction (n = 1). CONCLUSIONS. Injury to the vertebral artery during anterior approaches can be avoided by preoperative identification of anomalous arteries and by intraoperative attention to the midline. When the artery is injured, primary repair may be the optimal management strategy