Objective: The authors reviewed factors related to the surgical techniques attributed to surgeon-errors which result in
failures of the construct of the internal fixation of thoracolumbar fractures through transpedicular screws systems, and
how these could be avoided.
Patients and methods: The authors reviewed 280 consecutive patients with traumatic thoracolumbar fractures who
underwent spinal surgical fixation with short segment transpedicular screw instrumentation at two institutions, between
January 1997 and June 2005. All patients in this series were victims of high-force trauma. Among this series, 30
patients had a construct failure attributed to surgeon-related errors. Clinical evaluation of the patients was performed
on admission and at postoperative period using ASIA scale. All patients were radiologically investigated by plane xrays
and computerized tomographic scan spine on admission and occasionally MRI and 3D CT scan of the spine
when required. We used McAfee classification of thoracolumbar injuries. Surgical treatment was indicated in cases of
biomechanical instability of the spine and/or if a neurologic deficit was imminent or already present, the patients were
followed-up as regard to clinical and radiological evidence of construct failure.
Results: Thirty patients out of 280 patients with post-traumatic thoracolumbar injuries had construct failures. Main
clinical presentation of construct failure was severe pain and inability to walk at postoperative period. Radiologically
there was progressive spinal deformity with and without implant failures. The locations of the fractures in order of
frequency were as follows: L1 in 18 cases, L2 in 7 cases, T12 in 5 cases. The construct failure was in the form of
screw binding in 6 patients, screw breakage in 12 patients, screw/rod dislodgement in 3 patients, progressive
kyphosis in 5 patients, disengaged screw's cup in 2 patients, and broken rods in 2 patients.
Conclusion: Successful use of transpedicular screws in traumatic thoracolumbar fractures is predicated on
understanding of biomechanical properties of both the spine and implants. Great attention must be directed to
maintain the sagittal and coronal balances of the spine over the sacrum through reconstruction of comminuted
anterior vertebral column and appropriate distraction of the construct. In spite of routine use of pedicle, screw has not
been free of complications; the majority of construct failures is not actually device failures but instead is surgeonrelated
errors. |
