ROLE OF COMPUTED TOMOGRAPHY IN DETECTION OF LUMBAR DISC PROLAPSE

Lumbar Disc Prolapse

Abstract

Objective: To determine the sensitivity of CT scan in diagnosing lumbar disc prolapse.
Study Design: Validation study
Place And Duration Of Study: Combined Military Hospital Multan. From August 2009 to July 2010.
Patients and Methods: Patients with clinical suspicion of lumbar disc prolapse were referred from Neurosurgical OPD for CT scan of lumbar spine. The target CT finding was disc prolapse with compression of dural sac or narrowing of lateral recess / neuroforamina. Patients were divided into positive and negative cases on basis of detection of target finding by CT. All positive cases underwent surgery. Negative cases were first treated conservatively and only patients with persistent symptoms underwent surgery. The findings of CT as index test were compared with operative findings as gold reference standard.
Results: Total 61 cases were included in study, 51 positive cases and 10 negative cases. Mean age of patients was 44.6years. There were 42 males and 19 females. Positive cases after surgery showed 48 true positive and 03 false positive cases. Two negative cases showed persistent symptoms, underwent surgery and found positive for target finding (false negatives. Eight negative cases became symptom free after conservative treatment. These CT negative cases turning asymptomatic were ethically not feasible for surgery so assumed as true negative. The above data of 61 cases was computed in 2x2 table to calculate sensitivity (96%) and positive predictive value (94%) of CT scan in diagnosing lumber disc prolapse.
Conclusion: CT scan is having high sensitivity and positive predictive value in detecting lumber disc prolapse. It is reliable imaging modality in this regard.