Dorsal extradural thoracic disc fragment: a diagnostic challenge.

Dorsal epidural migration of an extruded disc fragment is an infrequent event, especially in the thoracic spine. An uncommon case involving a 55-year-old man is presented, with a 1-month history of paraparesis and thoracolumbar pain. Magnetic resonance imaging demonstrated a dorsally located, extramedullary mass at the T10-T11 intervertebral level. The lesion was suspected to be a tumor. The patient underwent a T10-T11 laminectomy. Intraoperatively, an encapsulated mass of soft tissue adherent to the dural sac was found. The pathologic diagnosis was inflammatory tissue and disc material. Six months after the operation, the patient remained asymptomatic, and radiologic control showed no residual mass. Although rare, a sequestered disc fragment should be included in the differential diagnosis of an enhancing posterior extramedullary thoracic mass. Preoperative diagnosis of such pathology is difficult because the clinical signs and radiologic images may not entirely exclude other more common thoracic spinal lesions, especially tumors.

Coated v noncoated ureteral metal stents: an experimental model.

PURPOSE: The purpose of the present study was to compare the standard metal stents with internally and externally coated metal stents in the pig model. MATERIALS AND METHODS: In nine female pigs weighing between 25 and 30 kg, the metal stents were randomly placed in either the right or left ureter, for a total of 18 stented ureters. Six ureters were stented with a Wallstent (Schneider, Zurich, Switzerland), six with a Passager stent (Boston Scientific, Natick, MA, USA), and six with a Corvita endoluminal graft (CEG) (Boston Scientific, Natick, MA, USA). Patency was examined by nephrostotomography 24 hours and 21 days after the initial procedure. RESULTS: Free flow of urine through the stents into the bladder was revealed in all ureters with the exemption of four cases where a Passager stent migrated into the bladder, jeopardizing ureteral patency. The Wallstent generated mild inflammation with metaplasia of the urothelium; the CEG a more pronounced inflammatory response in the adjacent ureter; and the Passager stent severe inflammatory reaction with necrosis of the urothelium. The sections of the Wallstents revealed the presence of a mild polypoid reaction adherent to the internal surface of the devices. The coated stents showed no tissue ingrowth through the lining material into the ureteral lumen, and thus, the urothelium was compressed beneath the prostheses. CONCLUSIONS: Our experimental results suggest that the standard Wallstent generates less inflammation of the surrounding tissues than coated stents. The coated stents have the advantage of minimal tissue ingrowth but have a tendency to migrate toward the bladder.