Efficacy comparison of pedicle screw placement technique and conventional method for pelvic external fixation

Abstract

Objective To investigate the clinical application of pedicle screw placement technique for pelvic external fixation. Methods A retrospective review was made on 63 patients(37 males and 26 females; 23-67 years of age)managed with anterior or combined anterior and posterior external fixation of pelvic fracture between February 2011 and May 2014. According the ways of screw insertion, the study was divided into two groups: observation group(screw was inserted using the pedicle screw placement technique, n=36)and control group(screw was inserted directly, n=27). Tile fracture classification was 11 patients with type B1, 7 type B2, 7 type B3, 5 type C1, 3 type C2 and 3 type C3 in observation group, and 9 patients with type B1, 7 type B2, 4 type B3, 4 type C1, 2 type C2 and 1 type C3 in control group. Operation time, rate of the penetration, X-ray fluoroscopy times, screw loosening rate, and postoperative complication rate were documented. Radiologic evaluation of the pelvis was detected with the Matta’s criteria. At the final follow-up, functional evaluation of the pelvis was evaluated with the score proposed by Cole et al. Results Period of follow-up was(14.7±3.2)months in observation group and was(13.8±3.1)months in control group. A total of 190 screws were placed in observation group and 138 screws in control group. Better results were found in observation group than in control group with respect to operation time[(18.8±4.1)min vs.(22.6±5.4)min], rate of the penetration(1.6% vs. 8.7%), X-ray fluoroscopy times(1.6±0.8 vs.2.2±0.9), and screw loosening rate(1.6% vs. 6.5%). There were no significant difference between observation and control groups in percentage of good to excellent reduction(89% vs. 85%)and function score[(35.6±3.0)points vs.(34.8±3.9)points](P>0.05). After operation, 3 patients with lateral femoral cutaneous nerve paralysis and none with wound infection were found in observation group; 3 patients with lateral femoral cutaneous nerve paralysis and one patient with wound infection were found in control group. Conclusion Either the pedicle screw placement technique or conventional technique achieves satisfactory clinical effect, but the former owns better results in operation time, screw insertion accuracy, fluoroscopy frequency and rate of screw loosening, suggesting a fast, safe, and effective screw placement method in pelvic external fixation that should be widely applied. Key words: Pelvis; Fractures; External fixators; Screw placement