Mono segmental fixation of selected types of thoracic and lumbar fractures; a prospective study.

AIM OF STUDY: A prospective study to evaluate the results of monosegmental fixation; fixation of the fractured level with the adjacent vertebra sharing the same disc, in selected types of lumbar and thoracic fractures. This technique aims at saving motion levels by fusion of the only affected motion segment without sacrificing other levels.

METHODS: Forty patients enrolled in this study between August 2011 and October 2013. The inclusion criteria were recent thoracic or lumbar vertebral fractures (less than 2 weeks). The fracture involves only one of the end plates of the vertebrae (either the superior or the inferior). The other end plate and both pedicles should be intact. The exclusion criteria were cervical fractures, fractures that include both end plates or pedicles of the vertebra, fracture dislocation, and load sharing classification score more than seven. All patients underwent monosegmental fixation with pedicle screw fixation. Eight patients were supplemented with interbody grafts. Radiological evaluation was done to assess local kyphosis angle, degree of compression of the anterior column, the degree of comminution, retropulsed fragment, neural canal compromise, integrity of the affected end plate, exclusion of pedicle fracture, and most important to assure that only one end plate is affected. All patients were assessed neurologically according to Frankel grading system. Patient were assessed by Denis pain scale and Denis work scale.

RESULTS: The age of the patients was of a mean of 34.5 years old. All patients were Frankle E at time of presentation and remained the same post-operative. The mean operative time from incision time to end of skin closure was 74.2 min. The mean blood loss was 230 ml. The pre-operative degree of local kyphosis; was of a mean 8.22°. This was improved to 2.25° at the immediate postoperative x-rays. At two years follow up, the loss of correction was of a mean 0.85° which was insignificant. The pre-operative percentage of height lost improved from a mean of 56.05 % to post-operative mean of 90.125 %. At the end of follow up, no pseudoarthrosis cases or metal failure were noticed.

DISCUSSION: Thoracic and lumbar fractures are common in young adults. Surgical treatment offers early rehabilitation and preserves spine alignment. Monosegmental fixation technique in selected types of dorsal and lumbar fractures offers spine stability and preserves motion segments. It fuses only one motion segment that is prone for later instability or deformity. Reconstrcution of the anterior column can be achieved through TLIF approach in combination of monosegmental fixation to achieve 360° fusion.

CONCLUSION: Monosegmental fixation is an effective technique. It can save motion segments in young patients with adequate spine stability and good functional outcomes.