Near-Infrared Spectroscopy for Pediatric Acute Scrotum and Testicular Torsion

The main goal of this prospective, non-randomized pilot study is to assess the utility of NIRS for the clinical diagnosis of the acute scrotum and testicular torsion. The sensitivity and specificity of NIRS for testicular torsion will be defined relative to surgical exploration, scrotal Doppler/B-mode ultrasound, and clinical follow-up. Last, we will assess the utility of intraoperative and postoperative NIRS for predicting testicular viability after testicular detorsion. To achieve this, standard care will be provided for all patients and at two or five time points NIRS measurements will be obtained privately so standard care is not biased by NIRS data. Outcome variables will include NIRS StO2 ( percent oxygen saturation) measurements, torsion status (yes/no), ultrasound parameters (testicular size, volume, echogenicity, presence/absence of Doppler flow, whirlpool sign, hydrocele, scrotal wall thickness), TWIST score variables, duration of pain, and duration of torsion. Study endpoints will include early withdrawal, screen failures, orchiectomy for torsion, and 1-2 week or 3 month post-surgical follow-up (see Figure 1). In this 5 year single center study, the maximum number of local subjects to be consented will be 750 subjects. No existing charts will be used in this prospective study.

Patients with acute scrotum will be evaluated by history, physical examination, and urinalysis per standard of care by staff in the ER, pediatric urology or pediatric surgery. At the surgeon's discretion, either a scrotal Doppler/B-mode ultrasound or emergent surgical exploration will be planned as the next step per standard of care. While waiting for preparation of either the scrotal Doppler/B-mode ultrasound or emergent surgical exploration, the patient and guardian will be informed and invited for study participation. If they agree to participate, they will be given a Fitzpatrick Skin Type (FST) Survey. This survey is a classification scale that was created in 1975 for predicting skin reactivity in PUVA (Psoralen plus ultraviolet A) photochemotherapy. [20] This survey asks the subject to grade his tendency to burn and ability to tan respectively within 24 hours and 7 days after the first un-protected sun-exposure in the early summer. There are four possible answers for "white"-skinned persons (skin type I, II, II, IV). Brown skin classification is skin type V and black skin classification is skin type VI. In the event that the survey has been missed, we will mail a survey to the patient/guardian with a pre-stamped and addressed return envelope. [20] Those that refuse study participation will receive standard of care treatment for the acute scrotum.

Those that accept study participation after informed consent will receive standard of care therapy for the acute scrotum and will be evaluated by NIRS. The NIRS measurements will not bias the treatments performed or not performed on the study patients, permitting standard of care treatment unbiased. The clinical data will be collected prospectively for each patient utilizing REDCap Data Collection Management and stored in the REDCap databases and the photographic database. Photographs will be taken of the scrotum. In addition, select participants will be asked if they will allow us to videotape the NIRS measurements.

At the surgeon's decision and discretion, either a scrotal Doppler/B-mode ultrasound or emergent surgical exploration will be planned as the next step per standard of care. While waiting for this to occur, the NIRS #1 measurement will be obtained. NIRS #1 is a series of 6 transcutaneous scrotal measurements, three on the left and three on the right. Each measurement is completely non-invasive, painless and takes <15 seconds each. Thus, no sedation or supplemental analgesia will be needed for NIRS. The NIRS probe will be placed on the anterior scrotum on the left and right sides, immediately overlying the testis but on the skin, to obtain the six total measurements. Thus, the unaffected testis will serve as the patient's own control. NIRS #1 will not delay the scrotal Doppler/B-mode ultrasound or emergent surgical exploration.

If the surgeon decides against surgical exploration, then standard care for the other causes of acute scrotum will be provided and the diagnosis will be no testicular torsion. The patient will be discharged home with a standard care follow-up in approximately two weeks in an outpatient urology clinic appointment. The subject will be given a NIRS Daily Diary to take home with them and record a five-day history of pain and recovery course. They will be asked to bring this back at the two week follow-up visit.