We report the effectiveness of instrumentation for aggravated thoracic myelopathy after laminectomy for ossification of the posterior longitudinal ligament (OPLL) and ossification of the yellow ligament (OYL). A 44-year-old woman with thoracic OPLL and OYL underwent laminectomy of T7-T11 at another hospital showed aggravation of myelopathy: muscle weakness and sensory loss developed in the sitting position, which however improved in the supine position. Radiological analysis showed that the kyphotic angle of T6-T12 was 6 degrees in the sitting position but it increased to 18 degrees in the supine position. Therefore posterior element defect due to laminectomy as well as obesity seemed to aggravate myelopathy. We corrected kyphosis using ISOLA and the kyphotic angle decreased corrected to 9 degrees. She became ambulatory with a cane after the surgery. Three months later we added anterior decompression and fusion of T7 to T9, and she could walk without any support. We recommend addition of posterior instrumentation after laminectomy in such obese patients with thoracic OPLL.
