Minimally invasive posterior spinal fusion in unstable thoracolumbar
Khan, Shahzad Ali
Background Unstable Thoracolumbar spinal fractures are conventionally treated by open reduction and internal fixation. This involves extensive mobilization of paraspinal muscles, which in turn leads to long-term disability in the form of chronic backache. One of the reasons fractures are stabilized is to prevent kyphotic deformity. Posterior lumbar stabilization done through a minimally invasive technique can achieve the same result as the open technique at the expense of less mobilization of the paraspinal muscles. Aim of the study The aim of the study was to assess the effectiveness of minimally invasive posterior spinal fixation in unstable Thoraco-lumbar fractures in our setting at Charlotte Maxeke Academic Hospital. Objectives To assess the effectiveness of Minimally Invasive Spine Surgery over a short term of minimum of 12 months regarding: Maintaining the correction of fracture kyphosis, Re-operations and Any serious Adverse Events Methodology This was a prospective interventional pilot study. Fractures were classified according to the AO comprehensive system. AO Comprehensive classification fractures A3, B1, B2, C1 and C2 were considered suitable for this technique. Pre-operative, immediate post-operative and one year follow up Cobb’s angles of fracture kyphosis were measured on plain lateral x-rays. Any Serious Adverse Events (SAE) that may have required re-operations were recorded over the minimum of 12 months follow up. Results Twenty patients met the inclusion criteria for this study. Post-operative follow up ranged between 12 and 22 months. There were 14 males and 6 females. The age ranged between 16 years to 54 years with mean of 33.9 years. L1 was the most commonly fractured vertebra. Eleven out of 20 patients sustained fracture of L1, 6 patients had fracture of L2 whereas 3 patients sustained fracture of T12. The AO classification types included one B1, five B2, seven C1 and seven C2 fractures. The pre-operative Cobb’s angle ranged from 7 degrees to 38 degrees with mean of 21.2 degrees. The immediate post-operative Cobb’s angle ranged between zero degrees to 16 degrees with mean of 8.3 degrees. The last follow up Cobb’s angle ranged between zero degrees to 21 degrees with a mean of 10.7 degrees. The loss of correction of fracture kyphosis ranged between zero degrees to 6 degrees with a mean of 2.4 degrees. The post-operative Cobb’s angle was maintained. There was no deterioration of pre-operative neurological status. There was no serious adverse event requiring a re-operation. Conclusion Minimally Invasive Posterior Spinal stabilization for thoracolumbar fractures had an acceptable outcome in our hands in appropriately selected cases. The average loss of correction of 2.4 degrees was in keeping with that found in open technique as well as MIS at other centers. While the number is less, this procedure can be recommended for well selected patients where skills are available.
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Orthopaedic Surgery Johannesburg, 2017