977 - Ossification of the Posterior Spinal Canal Resulting in Spinal Stenosis post laminectomy, foraminotomy and fusion of L4-L5 involving the use of morcelized autograft and structural allograft: A Case Report
Interventional Spine Physician Barrow Brain and Spine Phoenix, Arizona, United States
Case Diagnosis: Ossification of the posterior spinal canal leading to severe L4-5 canal stenosis
Case Description: A 72 year old female with a history of CKD V, L4-S1 laminectomy (2005) followed by L4-5 bilateral laminectomy revision and fusion (2008) presents to Spine clinic in June 2022 with low back pain and right sided radicular symptoms in an L5 distribution. MRI lumbar spine revealed severe canal narrowing at L4-5 (the fused segment) moreso than L3-4. Initially, the patient had significant relief with epidural steroid injections for one year however pain worsened and her symptoms became refractory to injection care. Surgical consultation was obtained and CT lumbar spine demonstrated that osseous/calcific material had developed in the posterior epidural space of L4-5. The patient would eventually go on to have a successful spinal cord stimulator trial.
Discussions: This represents a rare case in which low back pain continued to evolve and escalate secondary to ossification even 15 years post-procedure. It highlights the treatment options or lack thereof in the rare instance that ossification of the posterior epidural space occurs. Treatment with surgical intervention including attempted ossification removal at this high risk location may lead to even further neurologic injury. Targeted treatments for ossification of the epidural space are limited and need to be explored.
Conclusions: Ossification in the posterior epidural space following decompression and fusion of the lumbar spine is not an expected complication post-laminectomy and fusion of the lumbar spine. Given high fusion rates that continue to increase and prevalence of low back pain refractory to surgery, it is important to consider ossification as an etiology as well as educate patients on the risk of this complication which does not yet have standardized, safe treatment options.
