OBJECTIVESTo evaluate and analyze the role of posterior ligament complex (PLC) in determining therapeutic principle for traumatic thoracic-lumbar fracture.

METHODSFrom August 2005 to May 2008, 60 patients (38 male, 22 female) who suffered from the traumatic thoracic-lumbar fracture were carried out posterior operations. According to the Magerl traumatic thoracic-lumbar fracture classification system, these cases were classified to subtype A, B and C. The average age was 34 years (21 - 65 years). Magnetic resonance imaging (MRI) scan, which including both T1/T2 weight and fat-stir sequence, as well as the MRI negative film reading technique were used to evaluate the state of PLC. Furthermore, related physical or neurological examinations (such as severe skin bruising and sinking, broadening spinous process gap and tenderness, spinal cord or nerve root injury) and another X-ray or CT reconstruction films were taken to evaluate the the state of PLC synthetically. Above-mentioned results were compared with the final exploration results during operation and some parameters were analyzed.

RESULTSThe sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), misdiagnosis rate and rate of missed diagnosis of these sixty patients were 85.3%, 80.8%, 83.3%, 85.3%, 80.8%, 19.2%, 14.7% respectively. After 13 cases of thoracic-lumbar fracture-dislocation were eliminated, the sensitivity, specificity, accuracy, PPV, NPV, misdiagnosis rate and rate of missed diagnosis of remaining 47 cases were 81.0%, 80.8%, 80.9%, 77.3%, 84.0%, 19.2%, 19.0% respectively. There were 5 cases with MRI negative results before operation but positive results during operation. Contrarily, 5 cases with MRI positive results before operation but negative results during operation occurred.

CONCLUSIONSMRI is a main means for evaluating the state of PLC. Although the MRI fat-stir sequence as well as the MRI negative film reading technique are adopted, the state of PLC can not be estimated exactly before operation (especially for those unfracture dislocation cases). In order to estimate the state of PLC exactly, the related local physical examination and image technology as well as the location of the abnormal image signal in MRI film and time of injury must be analyzed synthetically.