Application of step-by-step in situ rod bending in posterior internal fixation of lumbar burst fractures

Abstract

Objective To evaluate the clinical outcome of the technique of step-by-step in situ rod bending used in posterior internal fixation of lumbar burst fractures. Methods A retrospective case control analysis was conducted on 76 cases of lumbar burst fractures hospitalized between March 2007 and March 2014. There were 48 males and 28 females, with a mean age of 40.4 years (range, 18-57 years). Fractured segments included L1 in 32 cases, L2 in 24, L3 in 14 and L4 in 6. According to the different rod bending methods, the subjects were divided into preliminary rod bending group (34 cases) and in suit rod bending group (42 cases). Operation time, amount of bleeding during and after operation, restoration of anterior vertebral height and Cobb angle, and visual analogue score (VAS) were compared between groups. Results Seventy patients were followed up for 12-36 months (mean, 20.9 months). One patient in preliminary rod bending group presented internal fixation loosening, and had implant removal 9 months after operation. No implant breakage occurred. Comparison of preliminary rod bending group and in situ rod bending group showed significant differences in operation time [(88.1±16.0)min vs. ( 79.9±14.7)min], amount of bleeding during operation [(88.3±21.2)ml vs. (74.0±12.5)ml ], amount of bleeding after operation [(71.5±17.3)ml vs.(62.1±16.0)ml] , restoration of anterior vertebral height [(74.1±7.8)% vs.(79.5±8.5)%], and restoration of Cobb angle [ (10.2±2.7)°vs.(8.8±2.6)°](P 0.05), while there was significant difference 9 months after operation [2.2±0.7)points vs. (1.9±0.7)points] (P<0.01). Conclusion In suit rod bending for lumbar burst fractures has advantages over preliminary rod bending in terms of operation time, blood loss, precise restoration and back pain. Key words: Lumbar vertebrae; Fracture fixation, internal; Kyphosis