Outcome of single level instrumented posterior lumbar interbody fusion using corticocancellous laminectomy bone chips

Background: Interbody fusion surgery has been considered by many to be a treatment of choice for instability in lumbar degenerative disc disease. A posterior lumbar interbody fusion (PLIF) has the advantages of spinal canal decompression, anterior column reconstruction, and reduction of the sagittal slips from a single posterior approach. The PLIF using double cage was a standard practice till many studies reported comparable results and lesser complications with single cage. Iliac crest was considered as an appropriate source of bone graft until comparable spinal fusion rates using local bone graft and cage emerged. Till date, there has been no report of corticocancellous laminectomy bone chips alone being used for spinal fusion. In this paper, we present radiologic results of single level instrumented PLIF, where in only corticocancellous laminectomy bone chips were used as a fusion device. Materials and Methods: It is a retrospective cohort study of 35 consecutive patients, who underwent single level instrumented PLIF surgery, wherein only locally obtained bone chips was used for spinal fusion. The average follow-up was 26 months. The indications for the surgery were as follows: 19 patients had disc herniations, with back pain of instability type, normal disc height on radiology. Ten patients had grade 1 spondylolisthesis, with significant back pain and translational instability on radiography. Three patients were redo spine surgeries, and three patients had healed spondylodiscitis with significant back pain and instability. All patients were regularly followed up and decision of spinal fusion or no fusion was taken at 2 years using modified criteria of Lee. Results: Of total 35 patients, there were 24 males and 11 females, with a mean age of 41 years. There were 16 patients with definitive fusion, 15 patients with probable fusion, 04 patients with possible pseudoarthrosis, and no patient had definitive pseudoarthrosis. The mean time for fusion to occur was 18 months. The average loss of disc height, over 2 year follow up, was only 3 mm in 8 patients. Three patients had a localized kyphosis of more than 3° at the fusion level. The average blood loss was 356 ml and average operating time was 150 min. Conclusion: Corticocancellous laminectomy bone chips alone can be used as a means of spinal fusion in patients with single level instrumented PLIF. This has got a good fusion rate.