TENS for Testicular Pain (ICO): A Randomized Controlled Trial

The overall aim of this study is to examine the efficacy of TENS on Testicular Pain using a randomized, placebo-controlled design. The results of this study will be used to inform a larger, federally-funded study. The study is a prospective, randomized, double-blinded and placebo-controlled crossover design (each participant completes all 3 study conditions) with randomization to 3 study conditions: 1) Active TENS; 2) Placebo TENS; or 3) No Treatment Control. Subjects will be tested 1x/week for 3 weeks. Each subject will receive the 3 treatments in randomized order. Importantly, the experimenter and subject will be blinded to the treatment condition. A second experimenter will administer the Active or Placebo TENS, or the Control to ensure appropriate blinding (to ensure no bias from knowing which TENS condition is given at each visit).

Participants. Thirty men with Testicular Pain (lasting >3 months), aged 18-99yrs will be recruited. Exclusion criteria includes: pain intensity rating ≤ 3/10, contraindications for TENS (pacemaker) or TENS use ≤ 5 years. Participants will provide written informed consent, as approved by the University of Iowa Biomedical Institutional Review Board. TENS Treatment. All subjects will receive each of the 3 TENS treatment conditions while sitting in an upright position. Four adhesive electrodes (2in x 2in) will be placed bilaterally on the: 1) sacrum (for pudendal nerve); and 2) groin (ilioinguinal nerve).

Active TENS includes high frequency TENS delivered for 30mins at a frequency of 100 Hz and pulse duration of 100μsec using the EMPI Select TENS unit (calibrated using an oscilloscope prior to study). The intensity will be increased until patients feel a "maximally strong but comfortable sensation" to ensure an analgesic effect.

Placebo TENS parameters will be identical to Active TENS (100 Hz and 100 μsec), but a novel placebo TENS unit, previously tested and validated will be used. The placebo device provides a current for 30sec and ramps off over 15sec to zero output. An indicator light remains on so it appears to the subject that the unit is still producing current. This unit has demonstrated nearly 100% blinding of investigators such that the investigator applying the TENS is unable to distinguish between the active and the placebo unit; approximately ~50% of subjects are successfully blinded using this unit.

The No Treatment Control includes application of TENS electrodes identical to the other 2 conditions, but the unit remains off. This condition will control for potential effects of repeat testing and any placebo effect.

Patient Measures. Pain will be assessed before and after TENS each session to measure any within visit changes in pain from the TENS intervention. Pain change will be measured using the: 1) Short-Form McGill Pain Questionnaire 27 with qualitative (i.e., sharp, distressing) and quantitative pain scales; and 2) 10-point numeric pain intensity rating scale (NRS) ranging from 0 (no pain) to 10 (worst pain imaginable); These pain measures are valid and reliable. Pain medication intake will also be assessed. Finally, pain-related catastrophizing (i.e., coping) will be measured using the Pain Catastrophizing Scale to determine if any responsiveness to TENS intervention is related to dispositional catastrophizing (i.e., their general catastrophizing levels prior to initiating the TENS study interventions).

Inclusion criteria

• Age >18 years to 99;
• Diagnosis of Idiopathic Chronic Orchialgia (ICO)
• English Speaking (does not need to be native language)

Exclusion criteria

• Pain intensity rating less than 2/10 at time of first session
• Inability to read or write
• Inability to follow directions

4 .Contraindications for TENS (Nickel allergy, pacemaker, open wound in TENS application area)

• TENS use in last 5 years.