A novel technique for reduction of unreducible lumbar fractures in ankylosing spondylitis.

Study Design: Retrospective case series study.

Purpose Of Study: Fractures in ankylosed lumbar spine are difficult to reduce and it is like attempting to reduce the ends of a long bone fracture of an extremity. Simple compression from the posterior results in the anterior column opening in lumbar spine because of the inherent lordosis present there, which usually requires combined approach, if the gap is extensive. Purpose of our study is to describe a new technique for reduction of lumbar fracture not reducing through conventional technique in ankylosing spondylitis. There are no techniques described for reduction of these complex fractures in the literature to the best of our knowledge.

Methods: Four patients were operated by a new modified staged posterior approach. Two patients had AIS D neurology, one patient had AIS A neurology and one patient had normal neurology (AIS E). Patients were operated in a staged procedure in a single sitting, as single posterior procedure did not allow for complete reduction of lumbar fracture. The patients were first positioned prone and instrumentation was done. To close the anterior gap, patients were then positioned lateral and reduction and stabilization of fracture was done.

Results: Mean age of the patients was 50 years. Average time of surgery was 3 h 40 min. All four patients operated with this modified posterior approach had fusion 6 months after surgery. There were no significant complications.

Conclusion: We recommend this technique to be used in fractures in lumbar ankylosed spine as they have tendency to open anteriorly after trauma. It helps in closure of anterior column in a single surgery and obviates the need for anterior surgery in these patients.