A study published in the Journal of Neurosurgery: Spine shows that quality of life, pain and disability, and psychological outcomes all improve after both primary and revision discectomy. However, improvement is diminished following revision surgery, and by the third discectomy patients were reporting falling quality-life adjusted years (QALY) scores. The study was led by Daniel Lubelski, Cleveland Clinic Center for Spine Health, USA.
The authors performed a retrospective review for all patients who had undergone a primary or revision discectomy at the Cleveland Clinic Center for Spine Health from January 2008–December 2011.
Among patients in the revision cohort, they identified those who needed a second revision discectomy. Patient quality of life measures were recorded before and after surgery, including responses to the EQ-5D health questionnaire, Patient Health Questionnaire– 9, Pain and Disability Questionnaire, QALYs. Cohorts were compared by using independent-sample t-tests and Fisher exact tests for continuous and categorical variables, respectively. The authors performed multivariable logistic regression to adjust for confounding. 
A total of 196 patients were identified (116 who underwent primary discectomy and 80 who underwent revision discectomy) with an average follow-up time of 150 days. There were no preoperative quality of life differences between groups. Postoperatively, both groups improved significantly in all quality of life measures. For QALYs, the primary cohort improved by 0.25 points (p<0.001) and the revision cohort improved by 0.18 points (p <0.001). QALYs improved for significantly more patients in the primary than in the revision cohort (76% vs 59%, respectively; p=0.02), and improvement exceeded the minimum clinically important difference for more patients in the primary cohort (62% vs 45%, respectively; p = 0.03).
Lubelski et al note that previous reports have indicated that “patient undergoing a primary discectomy have a 75–95% chance of satisfactory results as measured by pain and functional measures, whereas only 59–81% of those undergoing a revision discectomy will achieve the same”. Despite this, the results from this study show that improvements following revision surgery often exceeded the minimum clinically important difference threshold.
However, this was not true following a second revision surgery. Of the 80 patients who underwent revision discectomy, a third herniation occurred in 14 (17.5%). Of these, four patients (28.6%) chose to undergo a second revision discectomy and the remaining 10 (71.4%) underwent conservative management. For those who underwent a second revision discectomy, quality of life worsened according to all questionnaire scores. QALY scores for those undergoing the third procedure decreased from 0.65 after the second discectomy to 0.32 after the third (p=0.02). This contrasts significantly with the QALY scores of those who chose conservative treatment, which increased, if only slightly, from 0.42 to 0.43 (p=0.9). As the authors note, “This finding represented a significantly worse quality of life outcome for those undergoing surgery for the third herniation (p=0.03).”
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