Paul J. Apostolides

Elevated intracranial venous pressure as a universal mechanism in pseudotumor cerebri of varying etiologies

Article abstract-Pseudotumor cerebri (PTC), or idiopathic intracranial hypertension, is a syndrome associated with multiple clinical conditions. We hypothesize that most if not all etiologies result in an increase in intracranial venous pressure as a final common pathway. We studied 10 patients with PTC. Five had dural venous outflow obstruction as demonstrated by venography, and the five remaining patients had normal venous anatomy. Pressure measurements, made during venography in eight patients, all showed elevated pressures. Pressure measurements in the superior sagittal sinus ranged from 13 to 24 mm Hg (mean, 16.6 mm Hg). Patients with obstruction tended to have a high pressure gradient across the stenotic segment. Five patients with normal dural venous anatomy had elevated right atrial pressures (range, 6 to 22 mm Hg; mean, 11.8 mm Hg), which were transmitted up to the intracranial venous sinuses. Endovascular techniques, including angioplasty and infusion of thrombolytic agents in some cases, improved outlet obstruction from a hemodynamic perspective but were ineffective in consistently and reliably alleviating the clinical manifestations of PTC.Patients in both groups tended to respond well to conventional CSF diversion procedures. Our study suggests that elevated intracranial venous pressure may be a universal mechanism in PTC of different etiologies.This elevated venous pressure leads to elevation in CSF and intracranial pressure by resisting CSF absorption. Although the mechanism leading to venous hypertension in the presence of outflow obstruction is obvious, the etiology of increased intracranial and central systemic venous pressure in PTC remains obscure. NEUROLOGY 1996;46: 198-202

Thoracic Vertebrectomy and Reconstruction Using a Microsurgical Thoracoscopic Approach

A video-assisted thoracoscopic microsurgical approach was developed in the laboratory and subsequently used clinically to resect abnormalities of the thoracic vertebrae, to decompress the thoracic spinal cord, and to reconstruct the thoracic vertebral bodies. This report describes the development of the clinical operative techniques for microsurgical thoracoscopic vertebrectomy, neural decompression, and spinal reconstruction. This minimally incisional approach was clinically used in 17 patients to treat vertebral osteomyelitis, tumors, and compression fractures. Microsurgical thoracoscopic techniques were performed using several narrow, flexible, working portals placed in small incisions in the intercostal spaces. Access to the thoracic spine was achieved through the pleural cavity after temporary deflation of one lung using a double-lumen endotracheal tube. The parietal pleura, segmental vessels, and rib heads were dissected off the surfaces of the involved vertebrae to expose the region of interest. Long narrow spine dissection tools were used to perform the spinal decommpression and reconstruction. This technique achieved the same amount of spinal dissection as that achieved with conventional open spinal procedures and used microsurgical visualization techniques. The small incisions with reduced soft tissue dissection may reduce postoperative pain, shorten the length of hospitalization, and have cosmetic and functional advantages. Thoracoscopic vertebrectomies and reconstruction of the spine were technically feasilble procedures that were performed with excellent clinical results. This minimally incisional technique provides a viable alternative to thoracotomy or to posterolateral approaches for thoracic vertebrectomy and vertebral body reconstruction.

Threaded Steinmann pin fusion of the craniovertebral junction

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 one 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.

Use of the BendMeister Rod Bender for Occipitocervical Fusion: Technical Note

The creation of various curves in bendable metallic rods remains difficult. We describe a simple instrument that uses two bending levers to provide the mechanical advantage required to easily shape up to 5.5 mm diameter bendable metallic rods with precision, control, and minimal nicking or scratching of the metal surface. We have successfully used this tool to contour primary and secondary curvatures in threaded Steinmann pins and grooved titanium rods for occipitocervical fusion.

Microsurgical carotid endarterectomy

Microsurgical carotid endarterectomy has become an established procedure in the prevention of cerebrovascular accidents in select patients. The anatomy relevant to this procedure is described, and the preferred operative technique of the senior author is detailed.

Technique of pedicle screw fixation of the lumbosacral spine

Pedicle screw fixation is a safe and effective technique for fixating the spine for the promotion of fusion. It is most often performed in the lumbosacral spine to treat instability. The most common indication is degenerative instability; however, congenital, traumatic, neoplastic, or infectious causes of instability can also be treated effectively. Likewise, pedicle screw fixation can be performed in the thoracic and cervical regions. With few exceptions, the basic principles for placement are the same as for the lumbosacral region. This article offers a detailed description of our technique for placing lumbosacral pedicle screws.

Image-guided spinal surgery

Frameless stereotactic image-guided techniques may be used in spinal surgery to better define anatomical landmarks, to precisely localize pathological lesions and their borders, and to assist in the precise placement of instrumentation. This technology may be applied to surgery involving the entire spinal axis. Currently, it is best suited for dorsal approaches. However, modifications will soon be available that will vastly expand its application into the ventral region as well.

Technique of anterolateral thoracolumbar plating

During the last three decades, instrumentation of the thoracolumbar spine from the anterior perspective has evolved markedly. Plate systems have emerged as the preferred internal fixator of these segments. Anterolateral screw plate fixation provides the surgeon with a practical and reliable system for stabilizing the spine. The technique of plate fixation of the thoracolumbar spine from the anterolateral perspective is presented.