Clinical and technical factors in endoscopic skull base surgery associated with reconstructive success.

BACKGROUND: In this study, we identified key discrete clinical and technical factors that may correlate with primary reconstructive success in endoscopic skull base surgery (ESBS). METHODS: ESBS cases with intraoperative cerebrospinal fluid (CSF) leaks at four tertiary academic rhinology programs were retrospectively reviewed. Logistic regression identified factors associated with surgical outcomes by defect subsite (anterior cranial fossa [ACF], suprasellar [SS], purely sellar, posterior cranial fossa [PCF]). RESULTS: Of 706 patients (50.4% female), 61.9% had pituitary adenomas, 73.4% had sellar or SS defects, and 20.5% had high-flow intraoperative CSF leaks. The postoperative CSF leak rate was 7.8%. Larger defect size predicted ACF postoperative leaks; use of rigid reconstruction and older age protected against sellar postoperative leaks; and use of dural sealants compared to fibrin glue protected against PCF postoperative leaks. SS postoperative leaks occurred less frequently with the use of dural onlay. Body-mass index, intraoperative CSF leak flow rate, and the use of lumbar drain were not significantly associated with postoperative CSF leak. Meningitis was associated with larger tumors in ACF defects, nondissolvable nasal packing in SS defects, and high-flow intraoperative leaks in PCF defects. Sinus infections were more common in sellar defects with synthetic grafts and nondissolvable nasal packing. CONCLUSIONS: Depending on defect subsite, reconstructive success following ESBS may be influenced by factors, such as age, defect size, and the use of rigid reconstruction, dural onlay, and tissue sealants.

Evolution of Radiographic Changes of a Vascularized Pedicled Nasoseptal Flap after Endonasal Endoscopic Skull Base Surgery.

BACKGROUND AND PURPOSE: There is active research involving the radiographic appearance of the skull base following reconstruction. The purpose of this study was to describe the radiographic appearance of the vascularized pedicle nasoseptal flap after endoscopic skull base surgery across time. MATERIALS AND METHODS: We performed chart and imaging review of all patients with intraoperative nasoseptal flap placement during endoscopic skull base surgery at a tertiary academic skull base surgery program between July 2018 and March 2021. All patients underwent immediate and delayed (>3 months) postoperative MR imaging. Primary outcome variables included flap and pedicle enhancement, flap thickness, and flap adherence to the skull base. RESULTS: Sixty-eight patients were included. Flap (P = .003) enhancement significantly increased with time. Mean nasoseptal flap thickness on immediate and delayed postoperative scans was 3.8 and 3.9 mm, respectively (P = .181). The nasoseptal flap adhered entirely to the skull base in 37 (54.4%) and 67 (98.5%) patients on immediate and delayed imaging, respectively (P < .001). CONCLUSIONS: Our findings demonstrate heterogeneity of the nasoseptal flap appearance after skull base reconstruction. While it is important for surgeons and radiologists to evaluate variations in flap appearance, the absence of enhancement and lack of adherence to the skull base on immediate postoperative imaging do not appear to predict reconstructive success and healing, with many flaps "self-adjusting" with time.

An endoscopic curved Kerrison rongeur for spinal stenosis surgery.

OBJECTIVE: Adequate neural decompression with minimal structural alteration is the goal of lumbar stenosis surgery. Often because of limited visualization significant parts of the facet joints are removed enhancing the potential for developing instability. To overcome this problem we have developed a small curved Kerrison rongeur that contains a 10 000-pixel endoscope. This instrument allows one to visualize and decompress structures within the lateral recess that may have required more extensive removal of portions of the facet joints. METHODS: Ten patients with symptomatic lumbar spinal stenosis were decompressed using the endoscopic rongeur. RESULTS: Compression of the lateral dura and nerve root by the facet and ligamentum could easily be identified. In all cases the ligament could be easily removed and the facet joint was undercut only enough to decompress the nerve. CONCLUSION: This instrument has the potential for less invasive decompression of spinal stenosis and further study of its utility is planned.

An endoscopic dural retractor for spinal stenosis surgery.

Adequate neural decompression is the goal of lumbar stenosis surgery. Often because of limited visualization of the nerve root, significant portions of the facet joints are removed for decompression enhancing the potential for the development of instability. Clearly, the goal to better visualize the anatomy of the lateral recess while decompressing the nerve root may result in better root decompression and a smaller potential for instability secondary to bone loss. In order to accomplish this goal we have designed an endoscopic dural retractor that while retracting the dura permits simultaneous visualization of the anatomy of the lateral recess and the activity of instruments used to decompress it. The endoscopic dural retractor contains a 10000 pixel endoscope that allows a direct lateral view into the lateral recess while the dura is being retracted. This is a view that cannot be achieved with the operating microscope. One can easily appreciate the anatomy of the lateral recess including the facet joint, ligamentum flavum, lateral dura and nerve root. Ten geriatric cadaver lateral recesses were decompressed endoscopically using the endoscopic retractor. Compression of the nerve root by the facet and ligamentum could easily be identified. One could visually monitor the use of instruments on removal of ligamentum flava and bone compressing the nerve root. In all cases the ligament was easily removed and the facet joint was undercut only enough to decompress the nerve. This instrument has the potential for less invasive decompression of spinal stenosis and further study of its utility is planned.

Pain and spasticity after spinal cord injury: mechanisms and treatment.

STUDY DESIGN: A comprehensive survey of literature on the proposed mechanisms and treatment of pain and spasticity after spinal cord injury (SCI) was completed. OBJECTIVES: To define the current understanding of these entities and to review various treatment options. SUMMARY OF BACKGROUND DATA: The neurophysiologic basis of spasticity after SCI is well established. The mechanism of neuropathic pain after SCI remains conjectural, although considerable new data, much of it from animal models, now add to our understanding of this condition. METHODS: A comprehensive search and review of the published literature was undertaken. RESULTS: Treatment options for spasticity are effective and include oral medication (baclofen, tizanidine), intrathecal baclofen, and rarely, surgical rhizotomy or myelotomy. Selected patients with post-SCI pain can respond to surgical myelotomy (DREZ lesions) or intrathecal agents (e.g., morphine + clonidine), but the majority continue to suffer. CONCLUSIONS: Medical and surgical treatments for spasticity are established and highly successful. Management of post-SCI pain remains a clinical challenge, as there is no uniformly successful medical or surgical treatment.

Dural sinus thrombosis endovascular therapy.

Dural sinus thrombosis is a relatively rare, but potentially devastating disease. The problem occurs when there is extensive thrombosis of the intracranial dural sinuses, the outflow channels of venous blood from the brain. If recanalization does not occur, venous hypertension can lead to cerebral edema, infarction, and hemorrhage. Treatment of this disease usually involves anticoagulants, but with mixed results. Endovascular approaches using direct infusion of thrombolytic drugs into the occluded sinuses may result in excellent recanalization and improved patient outcomes.

A novel endoscopic approach to anterior odontoid screw fixation: technical note.

Techniques for operative management for type II odontoid fractures have continuously been refined with anterior odontoid screw arthrodesis having a clear advantage in maintaining normal motion. We have refined the technique of odontoid screw fixation further with the introduction of an endoscopic approach developed by the senior author. The necks of two partially embalmed cadavers were slightly extended under fluoroscopic guidance to simulate a reduced, anteriorly displaced type II fracture. Using a guide wire, graduated plastic sheath and endoscopic guidance, a solid 45 mm bone screw was passed through the odontoid with the aid of biplanar fluoroscopy. There were no apparent complications and no damage to surrounding vital structures. Anterior screw fixation of the odontoid is an established technique that provides adequate fixation, but the procedure can be technically demanding secondary to awkward tissue retraction. We present a percutaneous technique that obviates the need for tissue retraction while achieving an excellent result with only a modicum of effort.

Epidural abscess in the cervical spine.

A ten-year retrospective review of 23 cases of documented spinal epidural abscess in the cervical spine was undertaken to define the clinical features and establish current diagnostic and therapeutic criteria. Diagnosis was made by magnetic resonance imaging or myelography. Risk factors included intravenous drug abuse, diabetes mellitus, previous trauma, and a positive serologic test for the human immunodeficiency virus. A bacterial agent was isolated in 21 cases (91%). Neurologic deficits were present in 20 of the cases (87%) at the time of diagnosis. Erythrocyte sedimentation rate was elevated in all patients in whom it was measured. All patients were treated with appropriate antibiotics, usually for 6 to 8 weeks. Twenty-one patients underwent operative procedures using percutaneous aspiration (1 patient), the anterior approach (14 patients) or the posterior approach (4 patients), or a combination of the two approaches (2 patients). Four of ten patients who initially had less than antigravity strength were eventually ambulatory and continent; in each case, operative decompression was performed within 36 hours of initial consultation. Three patients who had no initial neurologic deficits remained intact.

Dolichoectatic aneurysm of common carotid artery: an animal model with histological correlation.

There is a limited understanding of the pathogenesis of dolichoectatic (dolicho = long; ectatic = dilated) aneurysms of elastic arteries. Therefore, we developed a model of dolichoectatic changes in elastic arteries by injecting porcine elastase into the media of the carotid artery of male New Zealand white rabbits. After 3 months, gross examination of the carotid arteries in vivo revealed dilated and tortuous vessels. The carotid arteries were then harvested, and cross-sections of the vessels were stained by the Verhoff-van Giesson stain. Histologically, the internal elastic lamina was dissolved in the most dilated areas. The elastic lamellae of the media were also digested and there was reorientation of the innermost medial smooth muscle layer. These gross and histologic changes were present in 80% of the treated carotid arteries and in none of the contralateral control vessels. Our study suggests the importance of the elastic lamellae for the maintenance of tubular shape and length of the carotid artery and describes a new chronic animal model of dolichoectatic aneurysm of the common carotid artery.