Near-infrared spectroscopy assessment of tissue saturation of oxygen in torsed and healthy testes

Diagnosis of Testicular Torsion and Differentiation From Other Pathologies Using Near-Infrared Spectroscopy

OBJECTIVE

To develop a near-infrared (NIR) spectroscopy device to diagnose testicular torsion with high sensitivity and specificity. Specifically, we aim to investigate the differentiation between testicular torsion from other pathologies such as orchidoepididymitis, varicocele, and hydrocele.

METHODS

Two LEDs with wavelengths of 660 nm and 940 nm were used as light sources in the device. Each wavelength was sent to the testicle successively, and a photodiode detected back-reflected diffuse light. The ratio of the light intensities of 660 nm and 940 nm was used as a diagnostic parameter. A multi-center clinical trial was performed in 5 different hospitals.

RESULTS

In total, 62 patients in urology clinics with acute testicular pain have been recruited for the study. The developed NIR spectroscopy correctly defined all 8 testicular torsion cases. Besides, 3 orchidoepididymitis, 1 varicocele, and 3 hydrocele cases were correctly distinguished from testicular torsion. Only 1 hydrocele case was misdiagnosed as torsion. The range of the ratio was between 0.14 and 1.16 overall measurements. The ratio varied between 0.14 and 0.3 for the testicle with torsion. The ratio was between 0.49 and 1.16 for the normal testicle and testicle with other pathologies mentioned above.

CONCLUSION

We have chosen the threshold ratio of 0.4 to differentiate between the normal and torsion testis and diagnosed all the torsion cases among all normal and other pathologies. The developed optical device to diagnose testicular torsion is inexpensive, user-friendly, and works based on objective criteria with high sensitivity and specificity in real time.

Near-infrared spectroscopy in the diagnosis of testicular torsion: valuable modality or waste of valuable time? A systematic review

BACKGROUND

Testicular torsion (TT) is a urological emergency that affects one in 4000 males younger than 25 years. Delays in the management of TT may result in testicular ischaemia, testicular necrosis, orchidectomy and infertility. This review assesses the validity of near-infrared spectroscopy (NIRS) as a diagnostic tool in the assessment and diagnosis of TT.

METHODS

A systematic search of Cochrane Database of Systematic Reviews, EMBASE, Google Scholar, PubMed, Scopus and Web of Science databases was performed in January 2019 using specific search terms. Selected studies were ranked and evaluated using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

A total of nine studies that included 253 subjects (88 animals and 165 humans) with a mean sample size of 28.1 (standard deviation 40.8) subjects were included. The mean difference in testicular tissue oxygen saturation between torsed and non-torsed testes (Δ%StO₂ ) were 45%, 42% (±5%), 26% and 5-18% in four animal studies and 2.0%, 3.0%, 6.7%, 6.8% and 23.0% in five human studies. The tissue oxygen saturation difference between contralateral healthy testes (controls) ranged from 1% to 10% in the five studies that alluded to this.

CONCLUSION

The current body of evidence does not support the use of NIRS in the work-up of TT. Well-designed clinical trials with large patient samples are required to determine whether NIRS may have some future role as a diagnostic modality in TT.

Frontiers in pediatric testicular torsion: An integrated review of prevailing trends and management outcomes

Testicular torsion remains the most frequent cause of testicular ischemia, especially in adolescents and young adults. Timely diagnosis and intervention are keys to saving the affected testicle. This review presents current trends in the diagnosis and treatment of torsion, potential pitfalls and consequent outcomes. Additionally, other salient issues surrounding testicular torsion are also discussed, including: pathogenesis of injury, legal ramifications, fertility outcomes, novel management techniques, and recent advances in diagnostic technology.

Transscrotal Near Infrared Spectroscopy as a Diagnostic Test for Testis Torsion in Pediatric Acute Scrotum: A Prospective Comparison to Gold Standard Diagnostic Test Study

PURPOSE

A rapid test for testicular torsion in children may obviate the delay for testicular ultrasound. In this study we assessed testicular tissue percent oxygen saturation (%StO2) measured by transscrotal near infrared spectroscopy as a diagnostic test for pediatric testicular torsion.

MATERIALS AND METHODS

This was a prospective comparison to a gold standard diagnostic test study that evaluated near infrared spectroscopy %StO2 readings to diagnose testicular torsion. The gold standard for torsion diagnosis was standard clinical care. From 2013 to 2015 males with acute scrotum for more than 1 month and who were less than 18 years old were recruited. Near infrared spectroscopy %StO2 readings were obtained for affected and unaffected testes. Near infrared spectroscopy Δ%StO2 was calculated as unaffected minus affected reading. The utility of near infrared spectroscopy Δ%StO2 to diagnose testis torsion was described with ROC curves.

RESULTS

Of 154 eligible patients 121 had near infrared spectroscopy readings. Median near infrared spectroscopy Δ%StO2 in the 36 patients with torsion was 2.0 (IQR -4.2 to 9.8) vs -1.7 (IQR -8.7 to 2.0) in the 85 without torsion (p=0.004). AUC for near infrared spectroscopy as a diagnostic test was 0.66 (95% CI 0.55-0.78). Near infrared spectroscopy Δ%StO2 of 20 or greater had a positive predictive value of 100% and a sensitivity of 22.2%. Tanner stage 3-5 cases without scrotal edema or with pain for 12 hours or less had an AUC of 0.91 (95% CI 0.86-1.0) and 0.80 (95% CI 0.62-0.99), respectively.

CONCLUSIONS

In all children near infrared spectroscopy readings had limited utility in diagnosing torsion. However, in Tanner 3-5 cases without scrotal edema or with pain 12 hours or less, near infrared spectroscopy discriminated well between torsion and nontorsion.