The presence or absence of an impalpable testis can be predicted from clinical observations alone
Objective To evaluate, in a prospective study, the accuracy of predicting the presence or absence of unilateral or bilateral impalpable testes from a clinical examination, particularly whether the contralateral descended testis (CDT) is hypertrophied.
Patients and methods Whether the ipsilateral scrotal appendages were palpable, and the size of the CDT, were determined before surgery in a series of patients, and compared with age-matched controls. Between 1992 and 2000, 100 impalpable testes in 86 consecutive patients (mean age at orchidopexy 45 months, range 6–223; 66% <36 months) were evaluated and treated. In addition to the presence or absence of palpable ipsilateral scrotal appendages, the size of the CDT, when present, and the intraoperative findings were recorded. Logistic regression analysis was used to model the probability of the presence or absence of the testis, as determined by the preoperative clinical findings alone.
Results Of the 86 testes that were located at surgery, 50 (58%) were intracanalicular, 28 (32%) intra-abdominal and the remainder (10%) were in the superficial inguinal pouch. Of 13 patients with the ‘vanishing testis syndrome’, the atrophic testicle was intracanalicular in nine, in the upper scrotum in three and intra-abdominal in only one. All viable testes were successfully relocated in the scrotum, with one atrophic after surgery. The positive predictive value (PPV, with 95% confidence interval) of a testis being present when the ipsilateral appendages were palpable and the CDT was not hypertrophied was 0.93 (0.83–0.97). Conversely, the PPV of the impalpable testis being absent when the appendages were impalpable and the CDT was hypertrophied was 0.95 (0.64–0.99).
Conclusion When evaluating and surgically treating impalpable testes, the presence of palpable ipsilateral scrotal appendages and a CDT with no hypertrophy is associated with a 93% likelihood of discovering a testis that can be successfully relocated to the scrotum. Conversely, when the ipsilateral scrotal appendages cannot be palpated and the CDT is hypertrophied, there is a 96% probability that the impalpable testis is absent (vanishing testis syndrome). This readily available information may be valuable in preoperative counselling and planning.
The presence of hypertrophy in the normal descended testis of boys with a unilaterally impalpable testis can be associated with monorchism [1,2]. The value of this clinical observation is limited, as only a minority of patients with a unilateral impalpable testis are found to have monorchism at surgery; in most, an undescended testicle is present. In a prospective study of unilateral impalpable testes we attempted to assess whether the presence of palpable scrotal appendages (i.e. tunica vaginalis, gubernaculum or vas deferens) on the undescended side correlated with the discovery of a testis on surgical exploration. In addition, we noted whether hypertrophy of the descended side correlated with monorchism, in the absence of palpable ipsilateral scrotal appendages.
Patients and methods
Between 1992 and 2000, 100 consecutive impalpable testes in 86 patients were evaluated and treated. Patients were excluded if a testis could be palpated under general anaesthesia before surgical exploration; palpation under anaesthesia occurred after surgical scrubbing and preparation, when the surgical scrub soap (with its lubricant qualities), may have enhanced palpability. The presence or absence of ipsilateral scrotal appendages was carefully assessed; the appendages had to be palpably extending in the direction of the inguinal canal to avoid the inclusion of irrelevant structures, e.g. scrotal fat. The length of the contralateral descended testis (CDT) was measured and compared with previously established normal standards ; the CDT was measured using a ruler, to maintain consistency with previously reported results and permit valid comparisons [1,3]. Compensatory hypertrophy of the CDT was defined as a testicular length of two sd above the mean for age. The operative approach consisted of an initial standard inguinal incision . The intraoperative findings were carefully recorded; the position, dimensions and structure of the undescended testis when present, and the location of the nubbin of tissue at the end of the vas deferens and vessels in those with ‘vanishing testis syndrome’. The mean (range) age of the patients at orchidopexy was 45 (6–223) months; 66% were <36 months old. The follow-up consisted of two visits at 1 and 4 weeks, allowing sufficient time to detect atrophy if it were to occur . Logistic regression analysis was used to model the probability of the absence of the testis.
Thirteen patients had the vanishing testis syndrome; only one testicular remnant was intra-abdominal, the remainder lying between the inguinal canal and upper scrotum. In all 13 there were pathological findings of blind-ending vas deferens and vessels and calcified or haemosiderin-laden fibrotic tissue. Hypertrophy of the CDT was recorded in nine of these 13 patients but in children 36 months old CDT hypertrophy was present in nine of 10. In the 13 patients, scrotal appendages were impalpable in six and palpable in the remainder. Conversely, in patients with no CDT hypertrophy, there were 86 testes (95.5%) associated with palpable appendages.
Of the 86 undescended testes, 50 (58%) were intracanalicular, 28 (32%) were intra-abdominal and the remainder (10%) were in the superficial inguinal pouch. In 83 (96.5%) of these patients, appendages were palpated before surgery, encompassing elements of the tunica vaginalis and gubernaculum in most and in two, vas deferens only; 74 (86%) testes were relocated into the scrotum using a standard orchidopexy technique (including a Prentiss manoeuvre in 15). In nine patients (10%) the internal spermatic vessels were divided to obtain enough length for the testis to reach the scrotum. Three pubertal patients underwent orchidectomy as they had a gross morphological anomaly. All but one testis survived the operation and maintained their size.
Logistic regression analysis was used to model the probability of absence of the testis, as determined by the clinical findings of impalpability of scrotal appendages and hypertrophy of the CDT. Both were very significantly related to absence of the impalpable testis (P=0.0065 and 0.0026, respectively); the overall model with both predictors was significant (P<0.001). Thus the positive predictive value (PPV, with 95% CI) of there being no testis when the appendages were impalpable and the CDT hypertrophic was 0.95 (0.65–0.99). In the absence of CDT hypertrophy, the PPV was 0.55 (0.16–0.88). If the appendages were palpable and the CDT not hypertrophic, the PPV for the testis being present was 0.93 (0.84–0.98). Excluded from this analysis were 14 patients with bilateral impalpable testes at presentation; all had bilateral palpable scrotal appendages and had bilateral undescended testes which were successfully relocated into the scrotum.
Finding a hypertrophic CDT correlates with absence of the impalpable testis, but this well documented phenomenon varies with age, the total volume of testicular tissue present and the quality of the descended testis . Therefore, it is not surprising that some patients with monorchia do not have CDT hypertrophy. In the present series CDT hypertrophy was defined as an intraoperatively measured length greater than the age-matched normal mean + 2 sd; 70% of the present patients with monorchia had CDT hypertrophy. Of the 10 patients aged 36 months, nine had CDT hypertrophy, an incidence much higher than those previously reported of 12–55%. In the present series, a testis was defined as impalpable only when it could not be palpated under general anaesthesia, just before surgical exploration. This criteria eliminated testes that would have been classified as impalpable based on the office examination alone and would have biased the results. In addition, when CDT hypertrophy is defined by a length of >2 cm  with no consideration of age, the accuracy of predicting the absence of an impalpable testis is considerably lower. Indeed, several of the present patients with a CDT of 2 cm had a testis on the impalpable side. These testes were smaller than normal for age, albeit with normal anatomy and ductal attachments. When CDT hypertrophy was defined as a testis size of only the mean + 1 sd for age, hypertrophy did not significantly contribute to prediction beyond the observation of impalpability of ipsilateral scrotal appendages alone. However, hypertrophy as defined here correlated significantly with monorchia.
The presence of CDT hypertrophy need not be the only finding predicting monorchia; indeed, the absence of any palpable scrotal appendages (gubernaculum, tunica vaginalis or vas deferens) only increases the likelihood of finding monorchia. In the present study, the PPV of impalpability combined with CDT hypertrophy was 0.95. This is not surprising as monorchia is thought to be secondary to in utero torsion of the spermatic cord with secondary atrophy of the testis. The ischaemic insult may also result in atrophy of the cord appendages and hence impalpability. However, the presence of palpable scrotal appendages (and no CDT hypertrophy) does not exclude the vanishing testis syndrome; in three of the present patients the atrophic testis was intrascrotal, resulting in palpability of what was thought to represent scrotal appendages. Conversely, in cases of maldescent, the appendages which precede the testis in descent are palpable. This readily accessible physical finding was reasonably accurate; in this series, the presence of palpable scrotal appendages on the impalpable side gave a 93% PPV of a testis being present at subsequent exploration. In addition, all of these undescended testes were successfully placed in the ipsilateral scrotum. In one procedure where the internal spermatic vessels were divided, postoperative atrophy was noted on follow-up.
In conclusion, when evaluating and surgically treating an impalpable testis, the palpability of the ipsilateral scrotal appendages and the presence or absence of hypertrophy in the CDT are two crucial physical findings that may predict monorchia or the presence of a testis. The palpability of the appendages may be more significant in predicting the presence of a testis that can be successfully relocated into the scrotum than the presence of CDT hypertrophy in predicting monorchia. This is a valuable finding, as most patients in this series had a testis and only 13% had monorchia. This readily available information may be valuable in preoperative counselling and planning.
H.-G.O. Mesrobian, Medical College and Children's Hospital Of Wisconsin, Milwaukee, Wisconsin, USA.