The differential utility of the Minnesota Multiphasic Personality Inventory. A predictor of outcome in lumbar laminectomy for disc herniation versus spinal stenosis.

One hundred six patients with disc herniation who underwent lumbar laminectomy and discectomy and 51 patients with spinal stenosis who underwent decompressive lumbar laminectomy were evaluated for surgical outcome at least 1 year postoperatively (mean: 18 months). All had completed the Minnesota Multiphasic Personality Inventory (MMPI) as part of the preoperative evaluation. The Hypochondriasis (Hs), Depression (D), Hysteria (Hy), Psychopathic Deviate (Pd), Psychasthenia (Pt), and Schizophrenia (Sc) scales were found to be predictive of surgical outcome in the herniation group. However, no MMPI scale was related to outcome in the stenosis group. Analysis of covariance showed this fact to be related to the differences in age between the two groups of patients, rather than a result of the differing diagnoses. The MMPI appears to be more useful in predicting surgical outcome in the young and middle-aged adult patient population with disc herniation and is not of predictive utility in the older stenosis population.