1. 2016;19;E151-E162Genotypic Analysis of SCN9A for Prediction of Postoperative Pain in Female Patients Undergoing Gynecological Laparoscopic Surgery
   Retrospective Analysis
   Guangyou Duan, MD, Guifang Xiang, MSc, Shanna Guo, MD, Yuhao Zhang, MD, Ying Ying, MSc, Penghao Huang, MSc, Hua Zheng, MD, Mi Zhang, MSc, Ningbo Li, MSc, and Xianwei Zhang, MD.

BACKGROUND: The SCN9A gene product is a critical component in human pain perception. Recent studies found that single-nucleotide polymorphisms (SNPs) in this gene contributed to the risk and severity of common pain phenotypes.

OBJECTIVES: In this study, we aimed to assess the use of SCN9A SNP screening for predicting postoperative pain.

STUDY DESIGN: A retrospective assessment of patients who underwent gynecological laparoscopic surgery.

SETTING: Department of anesthesiology, a teaching hospital, in a medical college, major metropolitan city, China.

METHODS: Twenty-nine candidate and tag SCN9A SNPs were analyzed in this study. Four hundred twenty-one patients who underwent gynecological laparoscopic surgery and refused postoperative patient controlled analgesia (PCA) were recruited and completed the study protocol. An additional 578 patients who voluntarily received PCA treatment were included for verification. Postoperative pain intensity was evaluated in all patients using numerical rating scale (NRS), and for patients receiving PCA analgesic requirements were also recorded.

OUTCOMES ASSESSMENT: The outcome was assessment of postoperative pain NRS and PCA analgesic requirements.

RESULTS: Ten different SCN9A SNPs exhibited significant associations with postoperative pain intensity, the incidence of severe postoperative pain, and postoperative PCA requirement. Of the candidate SCN9A SNPs, there was a statistically significant correlation between SNP rs6746030 and higher maximum NRS scores during the postoperative follow-up of non-PCA patients (P < 0.05). Furthermore, there was a significant association between the tag SNP rs4286289 and both increased postoperative maximum NRS scores (P < 0.05) and higher incidences of severe postoperative pain (P < 0.05) in non-PCA patients. Meanwhile, in PCA patients, rs4286289 exhibited the strongest association (P = 0.001) with increased requirements for postoperative analgesics, which indirectly strengthened the significant association between this SNP and higher postoperative pain.

LIMITATIONS: The limitations of this study include that it is an assessment of only Chinese women scheduled for gynecological laparoscopic surgery.

CONCLUSION: The current study provides evidence that postoperative pain was affected by SCN9A variability in gynecological patients. Notably, our results provide the first indication that SCN9A SNP rs4286289 can be used as a predictor for hypersensitivity to postoperative pain.