腰椎椎間板ヘルニア摘出術後3年を経過して対側の椎間孔狭窄をきたした1例

抄録

  Unlike lumbar canal stenosis of the central portion, nerve root tunnel stenosis cannot be diagnosed by myelography or magnetic resonance imaging (MRI), resulting in failed back surgery syndrome. We report a case of 60-year-old male who presented with severe right leg pain. A bilateral partial laminectomy and microdiscectomy of L4/5 was performed three years ago, and the patient's left leg pain and low back pain disappeared completely.

  MRI showed no recurrence of the obvious lumbar canal stenosis of the central portion of the spinal canal or disc herniation so he only received conservative therapy with non-steroidal anti-inflammatory drugs in the other hospital. We suspected right L4/5 foraminal stenosis by parasagittal MRI and diagnosed with L4 nerve root block. We performed L4/5 lateral fenestration and foraminotomy using the right extraforaminal approach.

  The extracanalicular L4 nerve root was subtotally covered with bony components (L4 transverse process, accessory process, and pars interarticularis, and L5 ascending joint), so we removed them carefully with an air drill. After that, L4 root was released completely. The patients symptoms disappeared immediately after surgery. Postoperative 3-dimensional computed tomography revealed sufficient preservation of the L4/5 facet joint and pars interarticularis.

  Although long-term follow-up is necessary, microsurgical lateral decompression without spinal fusion can be a useful surgical option for patients with nerve root tunnel stenosis after same level bilateral partial laminectomy.