Abstract

Objective: One of the new treatment methods for lumbar degenerative disc disease is percutaneous application of a hydrogel implant into the intervertebral disc. The aim of this method is to increase the disc height, to widen the neural foramen, and to decrease discogenic pain and leg pain caused by root compression. However, there may be serious complications related to intervertebral hydrogel implants that have been increasingly used during the last few years because of their minimally-invasive nature. A case with lumbar root compression due to hydrogel implant is being reported.
Case Report: A 61-year-old male was admitted with severe left leg pain due to compression of the left L5 root by a hydrogel implant that had been percutaneously introduced into the L4-5 disc level 6 months ago. On magnetic resonance imaging, a lesion compressing the left L5 root at the L4-5 disc level and mimicking a disc herniation was seen. It was hypointense on T1-weighted and hyperintense on T2-weighted sections. The implant was removed by an open surgery.
Conclusion: An intervertebral hydrogel implant swells up by absorbing water from adjacent tissues. Actually, this is the main mechanism of action by which it provides an increase of disc height. However, if it swells up excessively, it may spill over through the spinal canal and thus cause root or dural sac compression and neurological compromise.

Key words: intervertebral hydrogel implant, lumbar disc herniation, root compression