The effect of laminae lesion on thoraco-lumbar fracture reduction.

INTRODUCTION

The treatment of fractures involving the lumbar spine has been controversial. Laminae lesion may be complete or of the greenstick type (incomplete). Dural tears and nerve root entrapment may accompany these laminae fractures. The aim of this study is twofold, to assess the effect of different types of laminae fractures on the anteriorvertebral height restoration in upper lumbar burst fractures and to determine the incidences of the intraoperatively detected dural tear and neural entrapment in complete and incomplete laminae fractures to choose the optimal treatment.

MATERIALS AND METHODS

A retrospective review was conducted on 112 patients with 114 lumbar burst fractures treated operatively, age ranged from 17 to 55 years (mean age 32). Male to female ratio was (93%/7%), 8 females. Patients were divided into three groups, group 1 patients without lamina fracture, group 2 patients with complete type lamina fracture and group 3 patients with (percutaneous) incomplete type lamina fractures. All clinical charts and radiologic data of these groups were analyzed for their association with dural tears, neural entrapment and the impact of lamina fracture (complete and incomplete types) on the efficacy of anterior vertebral height restoration. The severity of injury was determined using the ASIA (Modified Frankel scale).

RESULTS

Out of 114 upper lumbar burst fractures, lamina fracture occurred in 34 patients (29.8%), complete lamina fracture occurred in 21 patients (61.7%), whereas incomplete lamina fracture occurred in 13 patients (38.3%). Dural tear was detected in 16 patients (47%) and was predominantly higher in complete type lamina fracture 12 patients (57%) when compared to 4 dural tears (30%) in incomplete lamina fractures. Analysis of the data revealed no significant difference in the preoperative anterior vertebral height loss and local kyphotic angle between the three groups. However the anterior vertebral height and local kyhpotic angle restoration were found to be affected by the presence of complete lamina fracture when compared to other groups with incomplete lamina fracture and without lamina fracture (P=0.001).

CONCLUSION

In upper lumbar burst fractures, complete lamina fracture is an indicator of injury severity. When detected preoperatively on CT or MRI scanning, it should be operated by open book laminectomy even if the patient is neurologically intact since it carries a high risk of neural entrapment, and its presence affects the intraoperative postural and instrumental trials for anterior vertebral height restoration.