Abstract: BACKGROUND: Traumatic spinopelvic dissociation severely damages the stability of the lumbosacral region, with many treatment complications, poor prognosis and many influencing factors. 
OBJECTIVE: To analyze the influencing factors of clinical efficacy of lumbopelvic internal fixation with nail-rod system treatment of traumatic spinopelvic dissociation.
METHODS: Complete data of 16 patients with traumatic spinopelvic dissociation from Tianjin Ninghe Hospital between September 2009 and September 2018 were analyzed retrospectively. All patients received lumbopelvic internal fixation with nail-rod system. There were 12 cases with nerve injury, of which 10 cases were treated with sacral nerve decompression. Two cases had no responsible fracture block on imaging and were not treated. Postoperative effect of treatment was evaluated according to the evaluation criterion of Japanese Orthopaedic Association and radiographic measurements of pelvic incidence and British Medical Research Council neurological function. Univariate statistical analysis was performed in the correlation between age, gender, timing of surgery, reduction quality, comorbid injury, degree of nerve injury and postoperative functional score. Among them, linear correlation analysis was conducted between age and Japanese Orthopaedic Association score. The correlation of gender, timing of surgery, reduction quality, comorbid injury, and degree of nerve injury with Japanese Orthopaedic Association score was analyzed with the Chi-square test.  
RESULTS AND CONCLUSION: (1) All patients were followed up for 17-38 months. (2) Postoperative evaluation results of Japanese Orthopaedic Association score showed that 4 cases were rated excellent, 5 good, 4 fair and 3 poor. (3) Imaging measurements showed that the pelvic incidence improvement rate of flexion sacral fracture was 78%, and the neutral type and extension type did not improve. (4) British Medical Research Council results demonstrated that neurological injuries were recovered of “excellent” in 5 cases, “good” in 4 and “no changes” in 3 patients. Clinical recovery rate of neurological injury was 75%. (5) Statistical analysis showed that the degree of nerve injury and accompanying anterior pelvic ring injury affected the surgical outcome. (6) It is indicated that the efficacy of surgical treatment of traumatic spinopelvic dissociation is affected by many factors. Based on the treatment of combined injury, the traumatic spinopelvic dissociation should be treated operatively with lumboiliac fixation early to maintenance the stability of spin-pelvic and pelvic ring, and exact decompression for neurological injuries is the key to achieve a satisfactory curative effect.

Key words: bone, spine, pelvis, separation, sacrum, fracture, internal fixation, plate, imaging