[Translated article] Pillar pain as a previously undescribed predictor of clinical outcome after carpal tunnel syndrome surgery: A prospective cohort study

Background and aim Pillar pain (PP) is a sensation of deep pain and allodynia in the thenar and/or hypothenar eminence zone, a complication associated with carpal tunnel syndrome (CTS) surgery. This study aimed to evaluate PP as a risk factor for a poorer clinical outcome of CTS surgery.Methods This prospective cohort study comprised 100 patients who underwent CTS surgery. Based on the onset of PP at 3 weeks, the sample was divided into two groups, and CTS symptoms were assessed using the clinical section of the Boston Carpal Tunnel Questionnaire (BCTQc). Clinical improvement was defined as a change of ≥2 points at 6 months compared to the preoperative score. BCTQc change values were correlated with the occurrence of PP at 3 weeks using the Chi-square test, and a risk study was assessed using the odds ratio (OR).Results The incidence of PP at 3 weeks was 36% among the 100 patients. At 6 months, in the "PP yes" group, 11 patients showed an improvement of ≥2 points, compared to 37 in the "PP no" group. Statistical significance was obtained (p=0.009), with an odds ratio (OR) of 3.11 (95% CI=7.4-1.3).Conclusions The appearance of PP at 3 weeks after surgery is associated with a 3.11-fold increased risk of showing a clinical improvement of <2 points in the BCTQc. Hence, PP is a prognostic factor for poorer clinical improvement after carpal tunnel surgery.