Cervical Myelopathy from Dilated Epidural Veins: Case Report of Intracranial Outflow Obstruction Treated with a Sigmoid Sinus-to-Internal Jugular Vein Bypass
Arnold B. Vardiman, MD*
Curtis A. Dickman, MD
Robert F. Spetzler, MD
Joseph E. Heiserman, MD†
B. Gregory Thompson, MD‡
*Texas Neuroscience Institute, Department of Neurosurgery, San Antonio, Texas, Division of Neurological Surgery
† Division of Neuroradiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
‡Department of Neurosurgery, University of Utah Medical Center, Salt Lake City, Utah
A 36-year-old hydrocephalic male became symptomatic with progressive cervical myelopathy caused by dilated epidural veins compressing the ventral surface of the upper cervical spinal cord. The veins were collaterals from the internal jugular veins, which were occluded bilaterally. The obstruction to venous outflow was treated with a sigmoid sinus-to-internal jugular vein bypass. The obstruction accounted for both the hydrocephalus and the myelopathy. The pathophysiology and treatment of this unique problem are reviewed.
Key Words: bypass, epidural veins, jugular vein, myelopathy, saphenous vein graft, sigmoid sinus
Symptomatic spinal cord compression caused by dilated epidural veins has rarely been reported.3 This article presents a patient whose spinal cord was compressed by dilated epidural venous collaterals. The dilation was the result of bilateral occlusion of the internal jugular veins.
Figure 1. T1-weighted, gadolinium-enhanced magnetic resonance image.
A 36-year-old, right-handed male presented with a long history of hydrocephalus, cerebral palsy, and unstable left hemiparesis. He also had a 6-year history of insidious, progressive quadriparesis. He had undergone multiple shunt revisions but had never had a ventriculoatrial shunt placed. During these 6 years, his condition had deteriorated from his needing a cane to needing a walker and, finally, to needing a wheelchair. His motor function, particularly the fine motor skills of his right hand, had deteriorated gradually, exacerbating his left hemiparesis.
Motor examination revealed a dense left hemiparesis. Abduction of the left arm was limited and painful due to contractures. He was capable of limited coarse movements of the left hand but only with great effort. The strength of his left lower extremity was 3/5. The right upper and lower extremities could overcome some resistance (4/5), but the fine motor movement of his right hand was diminished. Bilaterally, pin prick sensation below the level of the nipple was slightly decreased. Joint position sense was impaired on the left but intact in the right lower extremity. He was hyperreflexic, somewhat more on the left than on the right. He exhibited bilateral Hoffmann’s signs, Babinski signs, and sustained clonus. At presentation, he was confined to a wheelchair. He retained bowel and bladder function. He was mildly dysarthric as a result of his cerebral palsy; however, his cranial nerve examination was normal.
Magnetic resonance (MR) imaging revealed an extradural mass with a high-intensity signal ventral to the cervical spinal cord. The mass extended from the occipitocervical junction down to the level of C4 (Fig. 1). No flow voids were present. Postmyelography computed tomography (CT) confirmed the presence of the mass (Fig. 2).
Figure 3. Lateral cervical spine radiograph demonstrating Synthes (Synthes Spine, Paoli, PA) plate in place.
The patient underwent a modified anterolateral retropharyngeal approach so the upper cervical spine could be accessed. A left-sided approach was chosen to avoid the shunt catheter within his right neck. A midline corpectomy of the inferior half of C2 and the entire body of C3 was performed.
After the vertebrectomy was completed, profuse bleeding from the epidural venous plexus was encountered. The bleeding was controlled with Gelfoam® (Upjohn, Kalamazoo, MI), but further access to the epidural space was precluded by the rapid blood loss. After hemostasis was obtained, an autologous iliac crest bone graft was harvested and fitted into the corpectomy defect.
A Synthes (Synthes Spine, Paoli, PA) locking plate spanning C2-C4 was placed, and the wound was closed over a Jackson Pratt drain (Fig. 3). The patient’s intraoperative somatosensory evoked potentials were stable. Intraoperative fluoroscopy confirmed appropriate placement of the graft and plate. Analysis of a biopsy specimen revealed nondiagnostic fibrous tissue.
Upon waking, the only neurological deficit exhibited by the patient was the expected left hypoglossal palsy. MR angiography revealed complete bilateral obstruction of the internal jugular veins just caudal to the jugular bulb. The venous outflow was reconstituted through the epidural venous plexus and confirmed by conventional arteriography (Fig. 4). Detailed venography of the superior vena cava and external jugular system was performed to search for venous pathology in the neck and to identify recipient vessels for a bypass.
Figure 4. Lateral angiogram demonstrating bilateral obstruction of the internal jugular veins just caudal to the jugular bulb. Note venous return via a prominent epidural venous plexus ventral to the spinal cord.
The patient underwent a sigmoid sinus-to-internal jugular vein bypass with a saphenous vein interposition graft 8 days after the first operation. The patient was placed in the supine position with his head turned to the left and secured in position with the Mayfield (Codman, Raynham, MA) headholder. The patient’s right suboccipital area and right neck were prepared, and his right thigh and leg were prepared for the saphenous vein harvest.
A linear retroauricular incision was extended vertically to the mastoid tip. The suboccipital musculature was reflected off the subocciput to expose the junction of the temporal mastoid and occipital bones. The asterion was identified; the mastoid emissary vein followed its usual course through that point. After the bony landmarks were identified, the courses of the transverse and sigmoid sinuses and their junction were plotted. The Midas Rex®
(Midas Rex Pneumatic Tools, Inc., Fort Worth, TX) drill was used to skeletonize the sinuses and the junction, thereby exposing the pre- and retrosigmoid dura.
Next, a hockey-stick incision was made along the anterior border of the sternocleidomastoid muscle arcing posterosuperiorly toward the mastoid process. The initial plan to use the external jugular vein as the recipient for the graft was aborted when only a small atretic vessel was found. Anterior and medial to the sternocleidomastoid muscle was a robust internal jugular vein that had been reconstituted below the jugular foramen. Vessel loops were placed on the proximal and distal internal jugular vein to isolate this vessel for the bypass.