The efficacy of transcutaneous electrical nerve stimulation (TENS) in relieving postoperative pain has been assessed by means of a prospective randomized controlled trial in 62 male patients undergoing unilateral inguinal herniorrhaphy. Thirty-four patients received TENS and 28 patients received sham TENS for 48 h after the operation. Pain was assessed by means of linear analogue pain scales, analgesic requirements and peak expiratory flow readings. We were unable to detect any significant differences in these variables when the two groups were compared. These results do not support the use of TENS.

While most patients with otogenic pneumatoceles have presented acutely in extremis secondary to tension pneumocephalus, our patient has remained largely asymptomatic. Aetiology, clinical features and management options of temporal bone pneumoceles and otogenic pneumatoceles are reviewed.

SirWe read with interest the paper by Gilbert et al. describing a controlled trial to evaluate the effect of transcutaneous electrical nerve stimulation (TENS), for relief of pain following inguinal herniorrhaphy (Br J Surg 1986; 7 3 749-51). We have performed a similar study to evaluate the effect of TENS on postoperative pain following inguinal herniorrhaphy on 62 randomized male patients. Thirty-four of our patients received TENS and 28 received sham-TENS. In our study pain was similarly assessed using visual analogue pain scales, expiratory peak flow rates and analgesic requirements. We were also unable to demonstrate a significant difference between the two groups in any of these parameters.Gilbert et at. feel that technical factors such as the fixed electrical pulse frequency of 70 Hzand the placement ofelectrodes may explain the failure of TENS to significantly decrease postoperative pain. In our study, however, electrodes were also placed over the dorsal skin parallel to the spine to stimulate the dermatomes closer to the spinal column and