A case report of an unusual cause of postoperative leg pain after posterior lumbar fusion

We report the case of a 36-year old man who underwent elective posterior lumbar spinal fusion after presenting with bilateral leg pain with associated back pain. He had undergone a L5/S1 discectomy in 2001, which provided good symptomatic relief. On this admission, he underwent elective L4-S1 posterolateral fusion and bilateral L4/5 and L5/S1 decompression. Intra-operatively a pedicle screw had to be re-inserted after fluoroscopy confirmed a lateral breech. The patient had no major postoperative complications until the sixth day when the patient re-presented with acute leg pain and weakness. Following a local multidisciplinary meeting (MDT) an MRI showed a large haematoma at the right psoas muscle. CT angiogram confirmed a bleeding lumbar segmental vessel at the site of the previous misplaced screw and an emergency fluoroscopic guided embolisation of the vessel was performed. The patient recovered well post operatively and was discharged back to the community 12 days later. Haemorrhage, as in this case a psoas haematoma should be considered as one of the differentials in patients with recurrent post-operative radiculopathy following posterior lumbar spine fusion. This should be suspected particularly if there has been a misplacement of one or more screws as this can cause injury to blood vessels and be fatal for the patient.