Our study, presented at different stages [1–3], was of a pilot character but in this connection there were a substantial number of patients, 60 men and women in the final report, published a few years after the book on Interstitial Cystitis. There were and still remain many unsolved technical issues e.g. about the most efficacious electrical parameters to use, about optimal electrode shape and positioning, including the problem how to best overcome sensory limitations of percutaneous electrical stimulation, and also about the choice of most appropriate nerve afferents for an optimal effect; stimulation efficacy depends on the size of the responsible afferent nerve and the distance to the stimulating electrode as well as the selection of optimal electrical parameters for the desired effect [4]. We used standard TENS equipment, and cannot be sure that it was best suited for the effect we aimed to attain. It is should also be noted that there were no experimental studies as to treatment with this modality on this indication. More in-depth investigation of factors mentioned above would maybe have further improved the outcome; such studies are still feasible.

Still, in spite of possible shortcomings, the overall results were surprisingly good, and to some extent unexpected, especially so in patients with Hunner disease, ESSIC type 3C [5]. From a neurophysiologic point of view, an exceptionally interesting observation was the curative effect obtained following prolonged treatment. That included relief of symptoms, paralleled by endoscopic healing, and along with a profound reduction of MCs in bladder washings. Take for instance this case example [3]: A previously healthy woman was diagnosed with classic interstitial cystitis at the age of 49. There were a number of treatment attempts but the only one giving alleviation (although short-lived) was cystoscopic hydrodistension under anesthesia, performed every third month during a very long period of time. At all these frequently repeated cystoscopies the typical, circumscript Hunner lesions were seen. At the age of 66 she started chronic suprapubic, high-frequency TENS. There was continuous improvement during the following year and after one and a half year she was free of symptoms. The bladder capacity at distension during anesthesia at this stage had increased to 450 mL, compared to about 240 mL, constantly, at the very numerous distensions by way of the cystoscope before starting TENS. Three years later she was reexamined and the bladder capacity now was 800 mL; she was still free of symptoms. All lesions and signs of inflammation had disappeared; the bladder mucosa exhibited a few tiny, pale scars where lesions had been situated before. She was followed for 17 years after initiation of TENS, had no relapse and continued to use her device off and on. In this context it is worth noting that spontaneous healing of Hunner lesions had not reported. In this group of patients with Hunner lesions it is also worth noting the well documented, very long duration of stable clinical signs and symptoms before TENS was initiated; TENS was the starting point of a dramatic change. Unfortunately, though, the effect of TENS was not as convincing in non-Hunner disease, a heterogenic category where good treatment options are scarce.