Recurrent Spinal Canal Stenosis after Decompression and Fusion Surgery Due to Bone Overgrowth: Case Report.

Bone regrowth commonly occurs following lumbar decompression surgery. Although it is rare for neurological symptoms to occur due to bone regrowth, this study describes two patients who underwent both decompression and fusion surgeries but experienced spinal canal restenosisthat was severe enough to induce neurological symptoms. A 32-year-old man underwent posterior decompression and posterior lumbar interbody fusion for lumbar canal stenosis at the L4/L5 level 5 years prior. However, the sudden onset of lower back pain occurred 5 years later. Bone overgrowth on the left side was observed at the L4/L5 level. A second surgery was performed, and the patient's symptoms improved significantly. In the second case, a 56-year-old man underwent posterior decompression and posterior lumbar fusion at the L3/L4 and L4/L5 levels for an L4 burst fracture. One month later, he complained of lower back pain and underwent a second posterior decompression surgery. One year later, he presented to an outpatient clinic with lower back pain and neurological symptoms. Bone overgrowth was observed on both sides at the L4/L5 level. Thus, screw removal and laminectomy at the L3, L4, and L5 levels were performed as a third surgery. This study discusses the factors affecting bone regrowth and the methods that can be used to prevent it.