TENS compared to opioids in postoperative analgesic therapy after major spinal surgery with regard to cognitive function.

BACKGROUND

Long-term use of opioids causes cognitive decline. Transcutaneous nerve stimulation (TENS) applied preincisionally and postoperatively reduces postoperative opioid requirement and provides sufficient analgesia after major spinal surgery. Aim of this study was to find out the impact of TENS compared to opioids, prescribed for postoperative analgesia on early postoperative cognitive function.

METHODS

This study was prospective and randomised-controlled. Patients and observers were blinded to the study design. Forty-one patients of both sexes planned for lumbar interbody fusion were admitted and divided randomly into 2 groups. 35 Patients finished the study. Group A received TENS preincisionally and postoperatively, group B received piritramide intravenously (i.v.) by patient-controlled analgesia pump. The adjuvant analgesic therapy diclofenac 75 mg i.v. and the rescue medication paracetamol 1g i.v. was the same for all patients. Pain intensity was assessed by visual analogue scale (VAS). A battery of objective, standardized psychological tests was administered in the same order the day before surgery and 24 to 30 hours postoperatively.

RESULTS

The two groups were compared by pairs. Pre- and postoperative attention and memory differed significantly in both groups (p < 0.05). The postoperative fatigue was lower in group A (p < 0.05). Neither age, sex, body mass index, duration of operation, the need of rescue medication nor the incidents of hypotensive phases showed any significant association with postoperative cognitive decline.

CONCLUSIONS

Augmentation of fatigue in early postoperative phase was less in patients treated with TENS than with opioids for analgesic therapy after major spinal surgery. Further investigations on the duration of opioid therapy when cognitive functions decline are necessary.