EFFECTS AND MECHANISMS OF TRANSCUTANEOUS ELECTRICAL ACUSTIMULATION ON POSTOPERATIVE RECOVERY AFTER THORACOLUMBER VERTEBRAL FRACTURE

Background: The gastrointestinal (GI) disturbance is a frequent complication in patients with thoracolumbar vertebral fracture (TVF), especially in the postoperative period. Laxatives are sometimes of limited effect. Transcutaneous electrical acustimulation (TEA) has been reported to effectively treat functional or secondary constipation and accelerate postoperative gastrointestinal function recovery after abdominal surgery; however, it is unknown whether it has an ameliorating effect on GI disturbances in TVF patients after receiving posterior pedicle screw fixation surgery.
Objectives: This study was designed to investigate the effects of TEA on postoperative recovery and possible mechanisms involving autonomic functions.
Materials and Methods: A total of 81 TVF patients who underwent elective posterior pedicle screw fixation surgery were randomized to receive TEA or sham-TEA. After enrollment, electrocardiogram (ECG) was recorded for 30 min to assess autonomic function. TEA at ST36 or sham-TEA at non-acupoints was performed for one hour twice daily from 24 hours before surgery to postoperative day (POD) 3. Clinical symptoms were assessed in the form of diary. In the morning of POD1 and POD4, the ECG was recorded again for 30 min .
Results: 1) In comparison with sham-TEA, TEA enhanced postoperative recovery associated with lower GI motility (see Fig.1), including a reduction in time to defecation by 27.2% (P =0.002), time to first flatus by 17.2% (P = 0.027), an increase in the Bristol stool score (P = 0.014) and the number of spontaneous bowel movement (SBM,P =0.009). 2) TEA also improved other GI symptoms including abdominal bloating on POD1 and POD4 (P < 0.001 and P=0.001, respectively), straining during defecation (P<0.001) and sensation of anorectal blockage during defecation (P=0.02) in comparison with sham-TEA. 3) TEA reduced the visual analogue scale (VAS) wound pain score on POD1 (P=0.026), POD2 (P< 0.001) and POD3 (P< 0.001). 4) TEA but not sham-TEA increased vagal activity and decreased sympathetic activity (P < 0.001) on POD4 compared with POD1, assessed from the spectral analysis of heart rate variability derived from the ECG. The serum level of norepinephrine (NE) was significantly lower in the TEA group in comparison with the sham-TEA group on both POD1 (P=0.047) and POD4 (P=0.036). 5) The use of TEA was found to be an independent predictor of shortened time to first defecation.
Conclusions: Non-invasive TEA at ST36 is effective in promoting postoperative recovery in TVF patients by enhancing vagal and suppressing sympathetic activities.