Long-Term Outcome and Predictors of Transversus Abdominis Plane Block for Chronic Post-Hernioplasty Pain

Background/Objectives: Different analgesic techniques have been used in the clinical management of chronic post-hernioplasty pain (CPHP), with variable results. This study aimed to investigate clinical factors associated with long-term outcome of the transversus abdominal plane (TAP) block for CPHP. Methods: We retrospectively analyzed 26 patients with CPHP who were treated with single or multiple TAP blocks with local anesthetic and steroid. Patients were evaluated for pain and neuropathic pain intensity by a Numerical Rating Scale (NRS) and the painDETECT questionnaire (PDQ), for anxiety and depression by the Hospital Anxiety and Depression Scale, and for quality of life by the 12-item Short Form Health Survey (SF12). Results: At 6 months post-treatment, 20 patients (77%) presented substantial (>50%) or moderate (30-50%) CPHP relief and were considered responders. In responders, the 24-h average and maximum NRS pain significantly declined (p < 0.01) from 7.3 ± 1.3 to 2.6 ± 2.1 and from 8.8 ± 1.5 to 5.1 ± 2.0, and the neuropathic PDQ score from 9.1 ± 3.2 to 6.1 ± 1.3; the physical SF12 score improved from 36.5 ± 5.8 to 44.3 ± 7.5 (p < 0.01). Six patients failed to achieve a significant CPHP improvement and were considered non-responders. Non-responders presented a significantly (p < 0.05) longer CPHP, higher body mass index and neuropathic symptoms, and more frequent anxiety, depression, diabetes, and fibromyalgia. Conclusions: The TAP block with local anesthetic and steroid should be considered as a therapeutic option for CPHP. However, medical and psychiatric comorbidities negatively impact the TAP block effectiveness for CPHP.