You are in: eMedicine Specialties > Radiology > GENITOURINARY Testicular TorsionArticle Last Updated: Mar 10, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: David Paushter, MD, Vice Chair, Department of Radiology, The University of Chicago David Paushter is a member of the following medical societies: American College of Radiology, American Institute of Ultrasound in Medicine, Chicago Medical Society, Illinois State Medical Society, and Radiological Society of North America Editors: John L Haddad, MD, Clinical Associate Professor, Department of Radiology, Weill Medical College of Cornell University; Director of Body MRI, Department of Radiology, Methodist Hospital in Houston; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Arnold C Friedman, MD, FACR, Associate Chairman, Department of Radiology, University of Florida Health Science Center; Chief, Department of Radiology, Shands-Jacksonville Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center Author and Editor Disclosure Synonyms and related keywords: torsion of the spermatic cord, spermatic cord torsion, extravaginal torsion, intravaginal torsion, torsed testis, torsed testes, torsed testicles, retorsion, detorsion INTRODUCTIONSection 2 of 9
  BackgroundTesticular torsion, also termed torsion of the spermatic cord, is a relatively common and potentially devastating acute condition due to obstruction of the arterial blood supply to the testis.1 Fortunately, this entity is relatively well known, and it usually occurs with enough discomfort to lead to its diagnosis and subsequent testicular salvage. However, atypical presentations of testicular torsion, delayed recognition of the condition, and its confusion with other causes of acute scrotum can potentially delay diagnosis and lead to testicular necrosis necessitating orchiectomy. Diagnostic imaging, particularly Doppler ultrasonography, plays an important role in the assessment of the patient with acute scrotal pain.2 PathophysiologyTwo types of testicular torsion are recognized, and each has slightly different etiologies. Extravaginal torsion occurs in fetuses and in neonates. With this type of testicular torsion, the testis, epididymis, and tunica vaginalis twist on the spermatic cord.3 In the neonatal period, the testicle is often undescended, and this condition may delay the diagnosis of testicular torsion. Intravaginal torsion occurs more commonly in the peripubertal period than at other times. This type of testicular torsion is associated with a bell-clapper deformity in which the tunica vaginalis completely surrounds the testis. With the absence of the normal posterior anchoring, the testicle can twist freely. This congenital anomaly occurs in approximately 12% of males. FrequencyUnited StatesTesticular torsion has a prevalence of approximately 1 case per 4,000 population or 1 case per 125 males.4 Mortality/MorbidityThe salvage rate of torsed testes is fully dependent on the time between the onset of torsion and surgical detorsion.
SexTesticular torsion is an exclusively male phenomenon, although the female version, ovarian torsion, is well recognized and commonly associated with an ovarian mass. Age
AnatomyThe evaluation of ultrasonographic findings requires a detailed understanding of the scrotal anatomy. The testes are paired structures suspended in the scrotum by the spermatic cord. They measure approximately 2.0 X 3.0 X 4.0 cm in the adult and weigh 15-20 g. Each testis is surrounded by a fibrous capsule called the tunica albuginea. The testis contains seminiferous tubules, which are tightly coiled and arranged in wedge shaped lobules. The margins of the lobules are formed by septations arising from inner layers of the tunica albuginea. The seminiferous tubules converge toward the mediastinum testis and unite to form larger tubules, which in turn form a network of tubules, the rete testes. The rete testes unite to form efferent tubules at the superior pole of the testes. These efferent tubules (10-15 in number) constitute the head of the epididymis. The efferent tubules then unite to form a single lumen structure called ductus epididymis. The ductus epididymis forms the body and the tail of the epididymis, which is located on the posterolateral aspect of the testis. The tail of the epididymis undertakes an acute turn and continues as the vas deferens, which joins the spermatic cord. The testis and epididymis are vested by an extension of the peritoneum called the tunica vaginalis; this covers all but the posterior side. The blood supply to the testis is mainly from the testicular artery, a branch of the abdominal aorta. Contribution is also made by the deferential artery, a branch of the hypogastric or superior vesical artery; it primarily supplies the vas deferens. In addition, the cremasteric branch of the inferior epigastric artery forms a network over the tunica and forms an anastomosis at the testicular mediastinum. The testicular artery enters the testis through the mediastinum and branches under the tunica albuginea to form capsular arteries. The capsular arteries send radial branches, known as the centripetal arteries, into the substance of the testis. The centripetal arteries form U loops near their ends, increasing the effective area of supply. The testicular veins exit from the mediastinum and form a plexus called the pampiniform plexus. The plexus then combines into a dominant vein, which follows the testicular artery into the spermatic cord. The left testicular vein drains into the left renal vein, whereas the right testicular vein enters directly into the inferior vena cava. Clinical DetailsThe classic presentation of testicular torsion includes the following: acute onset of scrotal pain, frequently at night; a previous painful episode (in as many as 40% of patients); scrotal swelling and erythema; and difficulty in palpating the testis.5 Variant presentations may involve abdominal pain that mimics appendicitis. Nausea and vomiting are frequently associated findings. Patients may also have flank pain radiating to the groin. On physical examination, the affected hemiscrotum is swollen and frequently erythematous. The normal separation of the testis from the epididymis may not be palpable. An elevated, horizontal lie of the affected testis (Brunzel sign) and skin pitting at the scrotal base (Ger sign) may provide evidence in support of the diagnosis. With transillumination, the ischemic testicle may be visualized (blue-dot sign). Typically, no pain relief occurs with scrotal elevation (Prehn sign), as observed with acute epididymitis. The spermatic cord is typically thickened and tender. Tenderness alone may be indicative of acute epididymitis. Clinical examination may be confusing, as in cases with 360° or 720° twists, in which the testicular lie (position) may be normal. Undescended testes are much more likely to torse than those normally positioned. Bilaterality occurs in 10% of patients and may cloud the clinical picture. Differential considerations in the appropriate age group include acute epididymitis or epididymo-orchitis; abscess; torsion of the epididymal appendix; incarcerated hernia; hematoma; ruptured varicocele; or, rarely, scrotal tumor.6, 7 Detorsion may occur spontaneously, with subsequent luxury perfusion of the involved testis. History taking and physical examination play even larger roles in the diagnosis in this scenario. Preferred ExaminationIn general, laboratory tests are not diagnostically useful in distinguishing torsion from other acute scrotal syndromes. Urinalysis results are negative in 98%, and a mild leukocytosis may occur in as many as 30% of patients. Within the past decade, ultrasonography with color and power Doppler imaging has emerged as the primary imaging modality for the diagnosis of testicular torsion.8, 9, 10, 11, 12 It not only helps in corroborating the diagnosis by alteration of testicular echotexture but also provides valuable information on vascular perfusion of the testis. In addition, sonographic findings frequently allow other diagnoses to be made in those patients presenting with an acute scrotum who do not have torsion.13 Prior to the development of high resolution, real-time ultrasonography coupled with sensitive color Doppler, nuclear scintigraphy was the mainstay of tests available to evaluate the acute scrotum. Given associated radiation, less widespread availability, limited ancillary information, and the accuracy of color Doppler imaging, scrotal scintigraphy is no longer used as frequently.14, 15 In cases with a clinically ambiguous picture or with indeterminate sonographic findings, scintigraphy remains a viable imaging alternative.16 Information about the role of MRI in the diagnosis of torsion is limited, although MRI is likely to be highly sensitive.17, 18 However, with its limited availability, particularly at night, and its cost, MRI is unlikely to become a front-line examination for the patient presenting with acute scrotal pain. Limitations of TechniquesColor Doppler ultrasonography is highly operator dependent. In the diagnosis of testicular torsion, gray-scale findings are combined with dynamic flow information. Inaccurate results may be obtained in the prepubertal patient with small testicular volume or in cases with multiple imaging and Doppler artifacts. Such imaging artifacts may result from inappropriate gain settings and the non-use of slow-flow techniques.19 Testicular scintigraphy is straightforward, although it requires intravenous access. An infiltrated radionuclide bolus prevents an adequate examination. False-negative results are unusual. False-positive results are more frequent because of the changing scintigraphic appearance of infarction over time and potential interpretation errors. DIFFERENTIALSSection 3 of 9
Epididymitis Testicle, Malignant Tumors Testicle, Trauma Varicocele Other Problems to Be ConsideredTorsion of the epididymal appendage
MRISection 4 of 9
FindingsLimited information is available on the potential role of MRI in the diagnosis of acute testicular torsion. Findings from small studies to date suggest a high degree of accuracy with MRI, particularly when it is performed with contrast enhancement. These finding are corroborated by results of controlled animal models. In addition, phosphorus-31 magnetic resonance spectroscopy can demonstrate rapidly decreasing levels of adenosine triphosphate (ATP) associated with ischemia. Degree of ConfidenceTo our knowledge, no adequate, controlled clinical trials have been performed to assess the degree of confidence with MRI as a diagnostic tool for testicular torsion. However, if the torsion knot or whirlpool patterns are recognized in conjunction with testicular enlargement and absent vascularity, the diagnosis is virtually certain. ULTRASOUNDSection 5 of 9
FindingsOn normal gray-scale and color Doppler images, the testes are homogeneous and symmetric in echotexture, as shown on straddle views. The testes are relatively symmetric in size, but the normal range varies widely. On color or power Doppler sonogram, flow to the testes and epididymis should be symmetric. However, flow may be difficult to visualize in young patients. In patients with torsion, gray-scale images may show testicular enlargement due to engorgement; uniformly hypoechoic testicle (early); heterogenous, hypoechoic texture, which indicates necrosis and nonviability; echogenic areas inside the infarcted testis, which may represent hemorrhage; twisting of swollen cord, which gives the appearance of a torsion knot (an echogenic or complex extratesticular mass); or in infarcted testis, tunica albuginea and mediastinum, which have increased echogenicity (ie, target sign, which is more common in neonatal torsion). Color and/or power Doppler imaging should be performed in all cases. Flow to the affected testicle is absent, although normal or increased flow may be seen with spontaneous detorsion. The symptomatic side should be compared with the asymptomatic side by using the straddle view obtained with optimal technical settings. Epididymitis is visualized as an enlarged, hyperemic epididymis, usually with a diffusely affected area.20, 21 Involvement of the testis also produces enlargement and increased vascularity. A scrotal abscess, whether intratesticular or extratesticular, is typically seen as a complex fluid collection, often with a vascular capsule. Torsion of the epididymal appendage is easily recognized as a mass adjacent to the epididymal head without flow; this mass does not affect the testicular vasculature. Finally, an intratesticular hematoma may mimic a necrotic testis, but it typically has normal surrounding blood flow. An extratesticular hematoma appears as a complex, cystic collection clearly separate from but possibly displacing the testis. Degree of ConfidenceAn absence of flow in a symptomatic, enlarged testicle, with flow demonstrated in the contralateral testicle, is highly specific. Power Doppler and color Doppler imaging should be used together in prepubertal boys, but it demonstrates flow in only 79-90% of normal cases.22, 23, 24 Color Doppler and power Doppler sonography both demonstrate flow in almost 100% of postpubertal patients.25 Color Doppler and power Doppler imaging have similar sensitivities for demonstrating flow in small testes, although the combination of the 2 techniques has a sensitivity that exceeds the sensitivity of each alone. Overall, the specificity is 77-100%, and the sensitivity is 86-100%. False Positives/NegativesPosttorsion hyperemia may be confused with epididymo-orchitis, producing a false-negative finding. Capsular blood flow must be distinguished from intratesticular arterial flow; these observations may produce false-negative results. Although flow may be visible in one testis and is usually evident in the other, false-positive findings are possible in the young child. Technical factors (eg, erroneous flow settings, motion artifacts on power Doppler images) may produce false-positive or false-negative results. A scrotal abscess may cause a false-positive diagnosis of torsion because of the depiction of hyperemia surrounding a fluid core. Ultrasonography can be used to distinguish abscess from testicular torsion because of its combination of characteristic imaging and flow dynamics.26 NUCLEAR MEDICINESection 6 of 9
FindingsTechnetium-99m pertechnetate is the agent of choice, with an adult dose of 10-20 mCi and a pediatric dose of at least 5 mCi. Typically, immediate radionuclide angiograms are obtained, with subsequent static images as well. In the healthy patient, images show symmetric flow to the testes, and delayed images show uniformly symmetric activity. The appearance of testicular torsion on scintigraphy depends upon the chronicity. In acute torsion (usually <7 h), blood flow may range from normal to absent on the involved side, and a nubbin sign may be visible. The nubbin sign is a focal medial projection from the iliac artery representing reactive increased flow in the spermatic cord vessels terminating at the site of torsion. (This sign can also be seen in later stages.) Static images demonstrate a photopenic area in the involved testis. In the subacute and late phases of torsion (missed torsion), there is often increased flow to the affected hemiscrotum via the pudendal artery with a photopenic testis and a rim of surrounding increased activity on static images. This has been called a rim, doughnut, or bull's-eye sign. Acute epididymitis generally appears as an area of focal or diffuse increased activity in the involved hemiscrotum. Testicular appendix torsion has a variable appearance: it may have a normal scan or a focal area of increased or decreased activity. An abscess, tumor, or hematoma may be indistinguishable from a torsed testicle, demonstrating a hyperemic rim surrounding an area of decreased activity. Degree of ConfidenceScintigraphy has a sensitivity of 90% and a specificity of 60% in the diagnosis of testicular torsion. Color Doppler ultrasonography has distinct advantages in diagnosing nonvascular causes of acute scrotum. Scintigraphy may be more sensitive in the neonatal period than at other times because of the difficulty in detecting flow by means of Doppler imaging. Scrotal scintigraphy may be more sensitive than color or power Doppler imaging to the presence or absence of flow in the prepubescent testicle. False Positives/NegativesAn abscess, tumor, or hematoma may produce false-positive findings (rim sign). A hyperemic epididymis may be misinterpreted as a halo, producing false-positive study. Most false-negative studies are due to technical reasons or interpretative errors. INTERVENTIONSection 7 of 9
The suspicion of testicular torsion requires immediate surgical intervention to provide testicular salvage.27 Detorsing of the involved testis, with bilateral orchiopexy, is the standard surgical approach. This treatment is preferred because of the subsequent increased risk of future contralateral torsion. If the testicle is nonviable, orchiectomy is usually performed. Many patients with classic symptoms and signs of torsion require no imaging corroboration, and ultrasonography or nuclear medicine examinations should be reserved for those presenting with atypical symptoms. Testicular torsion is highly suspected if the following are present: appropriate age group, classic presentation, and consistent physical findings. In such cases, urgent operative repair can be undertaken without imaging verification. The normal contralateral testicle is at increased risk for torsion, and preventive orchiopexy is therefore performed. Spontaneous detorsion of the testis does occur, and it still requires surgical attention, even after the fact. Patient Education: For excellent patient education resources, visit eMedicine's Men's Health Center. Also, see eMedicine's patient education article Testicular Pain. Medical/Legal Pitfalls
See also the Medscape topic Medical Malpractice and Legal Issues. MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
Article Last Updated: Mar 10, 2008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
