Changes in MMPI profiles after low-back surgery.

Sixty-nine patients who had completed a Minnesota Multiphasic Personality inventory (MMPI) test preoperatively and had had low-back surgery for discogenic disease were seen in follow-up one to 11 years later. Each completed an MMPI test and pain drawing postoperatively, was examined clinically and radiographically, and was rated for surgical outcome. The preoperative MMPI hypochondriasis (Hs) and hysteria (Hy) scales were only modestly related to treatment outcome, but the postoperative scales were strongly related to outcome. Patients with good surgical outcome had lower Hs and Hy scores postoperatively than preoperatively, whereas patients with poor outcomes had higher Hs and Hy scores postoperatively. The MMPI profile of these operated low-back-pain patients was found to be changeable rather than static. The numerical value of the pain drawings was highly correlated with the elevation of the Hs or Hy scales. The MMPI should be utilized to identify patients with neurotic tendencies and prompt referral for psychologic treatment. Those patients who respond favorably to psychotherapy tend to have a better surgical outcome than those with untreated psychoneuroses or those who fail to improve with treatment.