Gas-Containing Disc Herniations: Dual Nerve Root Compression at a Single Disc Level

Abstract

A 72-year-old man presented with gas-containing disc herniations resulting in dual nerve root (exiting and traversing root) compression at the single level manifesting as lower back pain with the right anterolateral thigh and medial calf pain and no response to 4 weeks of conservative treatment. Physical examination revealed positive Lasegue's sign at 409 , but the patient had no evidence of neurological deficit. Magnetic resonance imaging showed two separate disc herniations, a posterocentral herniated disc that had migrated inferiorly at the L3-4 level and compressed the L4 traversing root, and another that had compressed the L3 exiting root in the extraforaminal area at the same level. Coronal computed tomography demonstrated the presence of gas in the spinal canal and extraforaminal area at the L3-4 level, and the vacuum phenomenon was also noted at the L3-4 intervertebral disc. Microscopic discectomy was performed using midline and paramedian approaches, and the presence of gas was confirmed by bubbles after pouring saline into the area intraoperatively. Histological examination revealed fibrous tissue. The patient was discharged with complete relief of pain. This is a rare case of symptomatic gas-containing disc herniations causing dual compression of exiting and traversing roots at a single disc level.

Epidural Gas Pseudocyst: An Uncommon Cause of Sciatica

“…Intradiscal air is common in degenerative spinal disease and is reported to occur in 46% of patients over the age of 40 on CT imaging. 3 Our case had the additional finding of extrusion of the gas into the intraspinal space (called a “gas pseudocyst”) and this caused radiculopathy–an occurrence uncommonly reported in the literature. 2 3 4 5 It has been speculated that the upper and lower vertebrae act “like pistons” 3 to push the trapped intradiscal gas into the spinal canal on weight bearing through an annular rent.…”

“…3 Our case had the additional finding of extrusion of the gas into the intraspinal space (called a "gas pseudocyst") and this caused radiculopathy-an occurrence uncommonly reported in the literature. [2][3][4][5] It has been speculated that the upper and lower vertebrae act "like pistons" 3 to push the trapped intradiscal gas into the spinal canal on weight bearing through an annular rent. 2 Surgery is indicated in cases where conservative treatment fails and in such cases an epidural pseudocyst has been found intraoperatively, manipulation of which releases the gas bubbles.…”

“…2 Surgery is indicated in cases where conservative treatment fails and in such cases an epidural pseudocyst has been found intraoperatively, manipulation of which releases the gas bubbles. 2,3 When surgery is indicated, some authors state that root decompression along with a thorough discectomy and excision of the posterior longitudinal ligament 4 is adequate but others opine that a vacuum phenomenon in the disc is an indicator of "vertical instability" and advocate fusion if these patients undergo operative intervention. 5 The primary imaging modality for a patient with sciatica is an MRI (following an initial assessment with plain roentgenograms).…”

Epidural Gas Accumulation in Connection with Canine Degenerative Lumbosacral Disease

“…The epidural gas accumulation can become surrounded by a fibrotic capsule and can grow with time (21). The ball-valve connection may cause an increase in the gas pressure inside the disc or cyst in the epidural space (35). The gas-filled cystic structures in the three patients in this study were part of the tissues compressing the cauda equina.…”

“…CT scans not only show that the mass within the spinal canal is partially composed of gas but also provide useful information about the condition of the disc and the rest of the lumbar spine. Surgery is recommended and generally successful in human patients who fail to respond to conservative therapy for gas-containing lumbar disc herniations (18–21, 33–35). The two canine patients treated by surgical removal of the causes of the lumbosacral stenosis, including the epidural gas accumulation, improved after the procedure and rehabilitation.…”