Prospective study of treatment outcomes with lag screw versus Herbert screw fixation in mandibular fractures.

The principle of axial compression for better adaptation of fracture segments, with the advantage of increased stability and early function, is a promising means of avoiding the bulky rigid plates used previously. This study was done to compare the treatment outcomes between Herbert screw and lag screw fixation in mandibular fractures. Thirty patients with oblique displaced or undisplaced mandibular fractures requiring open reduction and internal fixation with rigid screw fixation, under general anaesthesia, were included. Herbert screws were used in 15 patients (group 1) and lag screws were used in the other 15 patients (group 2). Patients were followed up at 1 week, 6 weeks, 3 months, and 6 months for postoperative occlusion, inter-fragmentary mobility, pain, nerve sensation, and isodensity values on panoramic radiographs. Postoperative occlusion, inter-fragmentary mobility, pain, and nerve sensation were similar in the two groups. Group 1 patients attained isodensity values similar to the final follow-up value much faster than group 2 patients (P<0.05). This study strongly suggests that the use of Herbert screws results in significantly faster healing as compared to lag screws, in terms of achieving higher isodensity values faster.