Cavernous malformations of the brainstem: experience with 100 patients.

OBJECT: In this study the authors review surgical experience with cavernous malformations of the brainstem (CMBs) in an attempt to define more clearly the natural history, indications, and risks of surgical management of these lesions. METHODS: The authors retrospectively reviewed the cases of 100 patients (38 males and 62 females; mean age 37 years) harboring 103 lesions at treated a single institution between 1984 and 1997. Clinical histories, radiographs, pathology records, and operative reports were evaluated. The brainstem lesions were distributed as follows: pons in 39 patients, medulla in 16, midbrain in 16, pontomesencephalic junction in 15, pontomedullary junction in 10, midbrain-hypothalamus/thalamus region in two patients, and more than two brainstem levels in five. The retrospective annual hemorrhage rate was most conservatively estimated at 5% per lesion per year. Standard skull base approaches were used to resect lesions in 86 of the 100 patients. Intraoperatively, all 86 patients were found to have a venous anomaly in association with the CMB. Follow up was available in 98% (84 of 86) of the surgical patients. Of these, 73 (87%) were the same or better after surgical intervention, eight (10%) were worse, and three (4%) died. Two surgical patients were lost to follow-up review. Incidences of permanent or severe morbidity occurred in 10 (12%) of the surgically treated patients. The average postoperative Glasgow Outcome Scale score for surgically treated patients was 4.5, with a mean follow-up period of 35 months. CONCLUSIONS: The natural history of CMBs is worse than that of cavernous malformations in other locations. These CMBs can be resected using skull base approaches, which should be considered in patients with symptomatic hemorrhage who harbor lesions that approach the pial surface. Venous anomalies are always associated with CMBs and must be preserved.

Cervical bone spur presenting with spontaneous intracranial hypotension. Case report.

Spontaneous intracranial hypotension due to a spinal cerebrospinal fluid (CSF) leak is a rare but increasingly recognized cause of postural headaches. The exact cause of these CSF leaks often remains unknown. The authors treated a 32-year-old man with a unique cause of spontaneous intracranial hypotension. He suffered an excruciating headache that was exacerbated by his being in an upright position. The results of four-vessel cerebral angiography were negative; however, magnetic resonance (MR) imaging of the brain revealed pachymeningeal enhancement and hindbrain herniation. A presumptive diagnosis of spontaneous intracranial hypotension was made. Myelography revealed extrathecal contrast material ventral to the cervical spinal cord as well as an unusual midline bone spur at C5-6. The patient's symptoms did not resolve with the application of epidural blood patches, and he subsequently underwent an anterior approach to the C5-6 spur. After discectomy, a slender bone spur that had pierced the thecal sac was found. After its removal, the dural rent was closed using two interrupted prolene sutures. The patient was discharged home 2 days later. On follow up his symptoms had resolved, and on MR imaging the pachymeningeal enhancement had resolved and the cerebellar herniation had improved slightly.

Ventricular shunt removal: the ultimate treatment of the slit ventricle syndrome.

OBJECT: The aim of this study was to assess the effectiveness of an algorithm used to evaluate and prescribe treatment for patients having slit ventricle syndrome (SVS). METHODS: All patients included in this protocol underwent fiberoptic intracranial pressure monitoring after removal or externalization of their ventricular shunt systems. A significant number of patients did not need extracranial cerebrospinal fluid (CSF) diversion and tolerated removal of their shunt systems without requiring further intervention. Patients who demonstrated a need for CSF drainage underwent an endoscopic third ventriculostomy, regardless of the putative cause of their hydrocephalus. Sixteen (72.7%) of 22 patients experienced resolution of or significant improvement in their SVS complaints after their inclusion in the protocol. Concomitantly, 14 (64%) of 22 patients were no longer shunt dependent after a mean follow-up period of 21.4 months. CONCLUSIONS: A significant number of patients debilitated by SVS may experience improvement in their symptoms and undergo shunt removal according to this protocol, improving their quality of life and simplifying their medical follow up.

Ventriculoperitoneal shunt failure as a complication of laparoscopic surgery.

OBJECTIVE: The authors report the first documented case of laparoscopically induced ventriculoperitoneal (VP) shunt failure. SUMMARY BACKGROUND DATA: Laparoscopic surgery has become a preferred method of accessing and treating a variety of intraperitoneal pathology. Surgeons can expect to encounter patients who have previously undergone placement of cerebrospinal fluid (CSF) shunts who present as candidates for laparoscopic procedures. Currently, the presence of a CSF shunt is not considered to be a contraindication to laparoscopy. We report the first documented case of laparoscopically induced VP shunt failure. CLINICAL HISTORY: A patient with shunt-dependent hydrocephalus underwent laparoscopic placement of a feeding jejunostomy. Postoperatively, clinical and radiographic evidence of shunt failure was noted. The patient underwent emergent shunt revision. Intraoperatively, an isolated distal shunt obstruction was encountered. Gentle irrigation cleared the occlusion. We believe that this shunt dysfunction was secondary to impaction of either soft tissue or air within the distal catheter as a consequence of peritoneal insufflation. CONCLUSIONS: It is concluded that laparoscopic surgery may represent a potential danger in patients with pre-existing CSF shunts. The risk of neurological injury faced by this patient population during laparoscopy is derived from peritoneal insufflation and relates to two primary concerns. The first is impaired CSF drainage due to a sustained elevated distal pressure gradient or, as in our case, an acute distal catheter obstruction. The second concern relates to the potential for retrograde insufflation of the CSF spaces through an incompetent shunt valve mechanism. Distal shunt catheter externalization performed in conjunction with a neurosurgeon during the laparoscopic procedure would prevent these complications. Internalization of the distal shunt catheter would then be performed at the completion of the laparoscopic procedure.

Completely dislocated hangman's fracture with a locked C2-3 facet. Case report.

The authors report a rare case of a hangman's fracture involving complete dislocation of C-2 onto C-3, accompanied by a C2-3 locked facet and asymptomatic bilateral vertebral artery injuries. The patient, a 25-year-old man who sustained a neck injury in an industrial accident, presented with a mild central spinal cord syndrome. His initial lateral cervical radiograph showed complete anterior dislocation of the C-2 body onto C-3, bilateral neural arch fractures, and a unilateral locked facet. The mechanism was likely flexion and compression. The grossly unstable spine and the locked facet were treated by posterior decompression, reduction, and C1-3 fixation. The patient recovered in several days and is without neurological deficit.

Differential effects of amino acid substitutions in the beta-sheet floor and alpha-2 helix of HLA-A2 on recognition by alloreactive viral peptide-specific cytotoxic T lymphocytes.

Crystallographic studies of the HLA-A2 molecule have led to the assignment of a putative peptide binding site that consists of a groove with a beta-pleated sheet floor bordered by two alpha-helices. A CTL-defined variant of HLA-A2, termed HLA-A2.2F, differs from the common A2.1 molecule by three amino acids: a Leu to Trp substitution at position 156 in the alpha-2 helix, a Val to Leu substitution at position 95 in the beta-sheet floor of the groove, and a Gln to Arg substitution at position 43 in a loop outside of the groove. Another HLA-A2 variant, termed CLA, has a single Phe to Tyr substitution at position 9 that is sterically located adjacent to position 95 in the beta-sheet floor of the groove. We have determined which of the amino acid substitutions at positions 9, 43, 95, or 156 could individually affect recognition by panels of A2.1 allospecific and A2.1-restricted influenza viral matrix peptide-specific CTL lines, using a panel of site-directed mutants and CLA. Recognition by allospecific CTL lines was generally unaffected by any one of the amino acid substitutions, but was eliminated by the double substitution at positions 95 and 156. Allorecognition by some CTL lines was eliminated by a single substitution at position 9 or 95. In contrast, recognition by A2.1-restricted matrix peptide specific CTL was totally eliminated by a single substitution at position 9 or 156. The substitution at position 43 in a loop away from the peptide binding groove had no effect on allorecognition or matrix peptide recognition. These results indicate that amino acid residues in the floor or alpha-2 helical wall of the peptide binding groove of the HLA-A2 molecule can differentially affect allorecognition and viral peptide recognition.