Patient Satisfaction And Minimally Clinically Important Difference In Pain Relief Vary By Procedure Type: A Comparison Of Microvascular Decompression And Radiosurgery For Trigeminal Neuralgia

Measurement of pain is challenging. The Penn Facial Pain Scale (PFPS), aka BPI-Facial, is a validated scale that measures pain intensity and its effect on activities of daily living (ADLs) in a quantitative manner. Statistically-significant differences in tests, however, may not translate to clinically-important differences. Thus, measurement of the minimum clinically important difference (MCID) is critical. Although we have measured the MCID in the trigeminal neuralgia (TN) population, we hypothesized that there may be significant differences based on procedure type: microvascular decompression (MVD) and stereotactic radiosurgery. PFPS has three domains (pain, interference with general ADLs, interference with face-specific ADLs) and was administered at initial visit and 1-month follow-up. A 7-point patient global impression of change was used as an anchor to calculate the MCID. A receiver operating characteristic (ROC) curve was constructed by calculating the accuracy of percentage changes in PFPS scores following intervention, where patients’ reports of “very satisfied” or “mostly satisfied” were considered satisfactory outcomes. The optimal cutoff point was calculated to define the MCID. Statistical significance was established with t-test or Fisher’s exact test. A concurrent series of 111 patients underwent MVD and 142 patients underwent GK. At baseline, PFPS scores in all three categories were statistically indistinguishable between both groups. The MCIDs in the MVD group was 57% for pain at worst, 35% for pain on average, 68% for interference with general ADLs, and 86% for interference with facial ADLs (AUC 0.87-0.93). The MCIDs in the GK group was 52%, 27%, 55%, and 45%, respectively (AUC 0.74-0.84). The number of patients who exceeded the MCID was higher in the MVD group for worst pain (Fisher’s; p=0.01), average pain (p=0.016), and interference with general ADLs (p=0.013). There was no difference for interference with facial ADLs (p=0.053). The MCID was higher for patients who underwent invasive surgery compared to outpatient GK. This suggests that patient expectations may vary based on procedure, and thus proper counseling preoperatively is paramount. A higher percentage of patients undergoing MVD achieved satisfactory outcomes as compared to patients undergoing GK.