Pediatric Testicular Torsion Workup

Updated: Jul 02, 2019
  • Author: Krishna Kumar Govindarajan, MBBS, MRCS, MS, MCh, DNB; Chief Editor: Marc Cendron, MD  more...
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Approach Considerations

Although contemporary imaging techniques will correctly reveal testicular torsion in most cases, pediatric urologists and surgeons have been hesitant to rely too heavily on these diagnostic tests. Concerns over false-negative findings and the lengthy wait necessary to complete studies at some centers (and the lack of availability of radiology services of any kind at certain hours) have led many surgeons to rely on the clinical history and examination to guide the decision for surgery in most cases.

According to this philosophy, a negative finding on surgical exploration is indeed a better outcome than a necrotic testis due to a missed diagnosis. Such practices are reinforced by medicolegal concerns, particularly given the well-documented incidence of false-negative imaging results. [33, 34] Thus, at many centers, imaging studies are used primarily when the diagnosis is uncertain but the index of suspicion for testicular torsion is low. [35]


Doppler Ultrasonography

The most widely used imaging modality for evaluation of testicular torsion is ultrasonography (US) with Doppler scanning for blood flow. An absent Doppler signal in the testicular parenchyma is diagnostic of testicular torsion. Initial parenchymal echogenicity is decreased but may increase once infarction has ensued.

Like any other US modality, however, Doppler scanning is highly operator-dependent. Important factors to consider include assessing the presence or absence of blood flow in the central parts of the testis, taking into account the Doppler signals only from the centripetal branches of the testicular artery, minimizing motion artifact, and carefully comparing findings with the contralateral testis to make a confident decision. [33]

A markedly enlarged, echogenic, and avascular or hypovascular epididymis is an ancillary US sign in testicular torsion. A hypervascular enlarged epididymis can occur in 5% of cases and should not be dismissed as epididymitis. [36] In old torsion, the testis size is small, appearing echo-poor, with a prominent, enlarged epididymis. In cases of intermittent and early testicular torsion, false-negative findings can be expected.

US can be used to differentiate extratesticular pathology (eg, hydrocele, abscess, wall edema, and hematoma) from testicular etiologies (eg, tumor and torsion). It is often helpful in diagnosing epididymo-orchitis, characterized by increased blood flow to the testis and epididymis. In case of a torsed testicular appendage, an extra testicular hyperechogenic nodule can be identified between the head of the epididymis and the upper pole of the testis. [30]

Overall, Doppler US has been reported to yield a sensitivity of 88% and specificity of 90% for identifying testicular torsion. However, the sensitivity and specificity of this modality widely varies among institutions, depending on factors ranging from equipment to operator and radiologist experience. False-positive findings can be particularly troublesome in infants because of difficult flow detection in prepubescent testes. [37, 38]


High-Resolution Ultrasonography

US with a high-resolution probe (at least a 7.5-MHz transducer) has been employed to detect testicular torsion. This study is used to examine the cord in its entirety, from the inguinal canal downward, to detect a spiral twist (whirlpool sign [39] ), yielding a sensitivity of 97.3% and a specificity of 99% in confirming torsion.

High-resolution US has been reported to be superior to Doppler US alone. Again, the concern is that the findings are operator-dependent. This study is widely used in tertiary care centers but may not be available in many community or rural settings. [40]


Nuclear Scanning

Radioisotope scanning has been reported to be highly accurate for diagnosis of testicular torsion. The ischemic area is seen as a photopenic zone in testicular ischemia. In cases of inflammation and infection, increased uptake is seen.

Unfortunately, this modality is not widely available, and even centers with functioning nuclear medicine capabilities may not have these available at all hours. For this reason, US is more widely employed in the United States in most settings. Radioisotope scanning involves a low dose of radiation (2 mSv). [41]


Other Tests

Urinalysis may help to suggest an infectious etiology of scrotal pain when positive for pyuria and bacteriuria; however, urinalysis should not be allowed to delay treatment in cases where acute testicular torsion is suspected.

Some authors have explored the use of near-infrared spectroscopy (NIRS) to study and compare the tissue oxygen saturation index on the right and left spermatic cords and thereby identify testicular torsion. [42, 43]  In a prospective comparative study that included 121 males younger than 18 years who had acute scrotum for longer than 1 month, Schlomer et al found that whereas NIRS was of limited value for diagnosing torsion in the study group as a whole, it did discriminate well between torsion and nontorsion in Tanner 3-5 patients who did not have scrotal edema or who had had pain for 12 hours or less. [44]

Initial experience with scrotoscopy suggests that this minimally invasive modality is able to diagnose testicular torsion; however, given that such an approach requires anesthesia and scrotal incision, it is unlikely to serve as a viable diagnostic tool except in patients with a very high index of suspicion for whom scrotal exploration under anesthesia is already indicated. [45]