Katie Pricola Fehnel and Lawrence F. Borges
Spontaneous intracranial hypotension (SIH) has been increasingly reported in the literature concomitant with the improved sensitivity of imaging modalities. Although typically associated with meningeal weakening, a handful of cases of SIH secondary to thoracic disc osteophytes have been reported. Five of 7 reported cases were treated with epidural blood patch (EBP) alone while 2 required surgical management. There is no standard operative approach; both anterior and posterolateral approaches can be cumbersome and associated with morbidity, particularly in young, healthy patients. The authors report a case of SIH in which a ventral dural tear secondary to a calcified thoracic disc was repaired via posterior thoracic laminoplasty with dorsal durotomy and intradural exposure of the ventral defect with transdural discectomy followed by primary closure.
A 34-year-old man presented with low-pressure headaches following axial load injury from a ski accident 5 years earlier. The patient's symptoms were refractory to a trial of conservative treatment and EBP, and he developed bilateral upper-extremity paresthesias. MRI of the spine demonstrated an extrathecal collection spanning the thoracic spine, and dynamic CT myelography identified contrast extravasation adjacent to a calcified paramedian disc at T9–10. The patient underwent posterior laminoplasty with neuromonitoring. A ventral dural defect was visualized via a dorsal durotomy, the penetrating disc osteophyte was removed transdurally, and the ventral and dorsal dura maters were closed primarily. Both somatosensory and motor evoked potentials were unchanged during surgery. The patient has remained asymptomatic more than 10 months postoperatively and he has resumed work as a surgeon.
Cases of SIH secondary to a calcified thoracic disc are rare with little precedent as to optimal surgical intervention. This case illustrates the potential usefulness of posterior laminectomy in nonmyelopathic patients in whom there is no evidence of canal compromise and for whom neuromonitoring is available. Additionally, surgeon experience and patient preference may guide surgical planning.
Brian Shaw, Frederick L. Mansfield and Lawrence Borges
✓ During the past decade, anterior approaches to the spine have been shown to be much more effective than laminectomy for the relief of pain and neurological deficits due to vertebral metastases. Laminectomy has failed because it does not allow adequate decompression of epidural lesions anterior to the thecal sac. In an effort to combine the advantages of the posterior approach with an adequate decompression, a one-stage posterolateral decompression-stabilization procedure was performed on nine patients with thoracolumbar spine tumors. The approach has been used for decompression and stabilization after thoracolumbar burst fractures. Marked lasting improvement was seen in all six patients with preoperative neurological deficits and in four patients with severe back pain and/or radiculopathy. Three nonambulators and two marginal ambulators could walk postoperatively without assistance. Of five patients who were working preoperatively, four returned full-time to their prior occupations. Three patients had serious complications, including one early postoperative death. No patient deteriorated neurologically due to the procedure. Although the series is small, it demonstrates that adequate one-stage decompression-stabilization of spinal epidural lesions is possible via the posterolateral approach and should be considered in certain cases as an alternative to the anterior approach.
Report of two cases
Lawrence F. Borges, Roberto C. Heros and Gerard DeBrun
✓ Two patients with large vascular carotid body tumors underwent preoperative intravascular embolization of the major arterial feeders. The tumor vascularity was reduced markedly, and complete surgical extirpation was accomplished without difficulty. The literature on carotid body tumors is briefly reviewed. The role of preoperative embolization in the treatment of these difficult tumors is emphasized.
Report of two cases
Lawrence F. Borges, Mark Hallett, Dennis J. Selkoe and Keasley Welch
✓ Two recently encountered patients with the anterior tarsal tunnel syndrome are presented. The various aspects of this probably under-recognized syndrome are discussed. Evidence is presented that this syndrome may be the result of abnormal stretch of the deep peroneal nerve.
Marius Maxwell, Lawrence F. Borges and Nicholas T. Zervas
✓ The authors present the case of a patient in whom intradural metastasis from renal cell carcinoma spread to the cauda equina. To the authors' knowledge, this is only the second report of its kind. This male patient had undergone nephrectomy for the treatment of renal cell carcinoma for 5 years and was diagnosed as having metastatic lung disease 1 year prior to admission. The patient presented with lower back pain that radiated to both legs, but he exhibited no sensorimotor deficits. The majority of cauda equina tumors are primary tumors, and metastases are very rare. The literature is reviewed with reference to current molecular genetic paradigms of metastatic renal cell carcinoma.
Appraisal of a medical-grade aliphatic polyurethane and a polysiloxane-carbonate block copolymer
Damianos E. Sakas, Komporn Charnvises, Lawrence F. Borges and Nicholas T. Zervas
✓ Two types of artificial membranes, a medical-grade aliphatic polyurethane and a polysiloxane-carbonate block copolymer, were tested as substitutes for dura in 24 and 12 rabbits, respectively. The films were placed either epidurally, subdurally, or as dural grafts in equal subgroups of animals. The postoperative course was uneventful with no manifestations of convulsive disorder or cerebrospinal fluid leak. The animals were sacrificed 3, 6, or 9 months after implantation of the artificial membranes. Both types of artificial membranes were easily removed from the underlying nervous and the other surrounding tissues. The histological examination failed to reveal adhesions, neomembrane formations, or any type of foreign body reactions to the polyurethane film. The implantation of the polysiloxane-carbonate film caused no reaction when it was applied epidurally. As a dural graft, the polysiloxane-carbonate copolymer induced the formation of a thin neomembrane of one to two layers of fibroblasts which formed a watertight seal of the dural defect. A similar thin neomembrane was found to encase this artificial membrane in the group of animals in which it was implanted subdurally. There was no foreign body reaction to the polysiloxane-carbonate film. The authors conclude that these materials hold promise as dural substitutes or in the prevention of spinal dural scarring, and should be evaluated clinically.
Report of two cases
Stephen B. Tatter, Lawrence F. Borges and David N. Louis
✓ Central neurocytoma is a neuronal neoplasm that occurs supratentorially in the lateral or third ventricles. The authors report the clinical, neuroradiological, and neuropathological features of two neurocytomas arising in the spinal cord of two men, aged 65 and 49 years. The patients presented with progressive neurological deficits referable to the cervical spinal cord. Magnetic resonance imaging revealed isodense intramedullary spinal cord tumors at the C3–4 level. Both tumors were initially misdiagnosed as gliomas. In Case 1 the correct diagnosis was made after electron microscopy revealed neuronal features. Immunostaining in Case 2 revealed that tumor cells were positive for synaptophysin and negative for glial fibrillary acidic protein, strongly indicating a neuronal tumor. It is suggested that this spinal cord neoplasm be included under the designation “central neurocytoma.”
Emad N. Eskandar, Lawrence F. Borges, Ronald F. Budzik Jr., Christopher M. Putman and Christopher S. Ogilvy
Object. Although the pathophysiology of spinal dural arteriovenous fistulas (AVFs) has recently been elucidated, the optimal treatment strategy for these lesions has yet to be defined. Current management techniques include endovascular embolization or microsurgical obliteration.
Methods. The authors reviewed the records and angiograms of all patients with spinal dural AVFs treated at Massachusetts General Hospital over a 6-year period (1992–1998). During this period, it was intended initially to treat all patients with embolization and to reserve surgery for those in whom endovascular treatment failed or in cases in which pretreatment evaluation suggested that endovascular therapy would be ineffective or unsafe.
A total of 26 patients with spinal dural AVFs were treated: there were 22 men and 4 women with a mean age of 65 years (range 39–79 years). Lesions were located in the following areas: five in foramen magnum/cervical, 13 in thoracic, five in lumbar, and three in sacral. Twenty-three (88%) of 26 patients underwent embolization and three (12%) of 23 patients underwent surgery as the primary mode of treatment. Of the 23 patients in whom embolization was performed or attempted, nine (39%) ultimately required surgery. All patients were stabilized or improved following definitive treatment, as assessed by the Aminoff—Logue scores. There was one death secondary to a myocardial infarction.
Conclusions. These data demonstrate that endovascular therapy can be successful as an initial treatment for the majority of patients; however, there is a 39% failure rate, which is not observed following surgical therapy. Once a definitive therapy has been achieved using either technique virtually all patients are either stabilized or improved.