Study design: An in vitro biomechanical study.
Objective: To examine disc integrity at levels adjacent and next adjacent to the fractured vertebra and to determine if the disc injury can be revealed by radiographs.
Summary of background data: Thoracolumbar burst fracture is one of the most common spinal injuries. A fractured vertebra is easy to recognize, but the associated disc injuries are less well known. The disc injury may not be apparent in radiographic images. Quantitative discomanometry, which measures disc pressure and the injected volume, has been found to detect disc injury.
Methods: Nine specimens (T11-L3) with L1 burst fracture included adjacent discs (T12-L1 and L1-L2) and next-adjacent discs (T11-T12 and L2-L3) and were examined with radiographs and quantitative discomanometry, before and after the burst fracture. Statistical analyses were used to determine if the nine quantitative discomanometry parameters, in each of the four discs, were changed by the burst fracture and if the two next adjacent discs sustained different injuries.
Results: After the burst fracture both the adjacent discs were shown to be injured by both radiographic and quantitative discomanometry examinations. Whereas both next-adjacent discs were found to be uninjured by radiograph examination, the quantitative discomanometry found the lower next-adjacent disc (L2-L3) to be injured.
Conclusions: Quantitative discomanometry was successful in finding disc injury, where the radiographs found none. The lower level, next adjacent disc is susceptible to injury during the burst trauma.