A nubbin refers to an atrophic testis likely from prenatal testicular torsion. Testicular nubbins are often found during the evaluation and treatment of the unilateral non-palpable undescended testis.
Two controversies surround the evaluation and management of testicular nubbins:
Contralateral testicular fixation
The testicular torsion occurring before birth is due to the lack of fixation of the testicle to the scrotum. After a month of life, the testicle should be fixed to the scrotum. Torsion can still occur after the testis is fixed, but only occurs in patients born with a malformation called the “bell clapper deformity” and is rare at around 1/6000 chance.
Patients undergoing surgery to remove a nubbin are usually older than 6 months of age and thus their testis is fixed to the scrotum. Thus, contralateral testicular fixation would need to be done in 6000 patients in order to prevent 1 case of testicular torsion.
Surgeons that believe they can perform a contralateral testicular fixation with a complication rate of less than 1/6000, recommend them to their patients and vice-versa. I personally don’t do them as I think the chances of damaging a testis from the fixation is likely more than 1/6000.
Laparoscopy first or scrotal exploration first
Most nubbins are found during surgical exploration for a unilateral non-palpable undescended testis.
When the testis is non-palpable under anesthesia, exploratory laparoscopy is recommended to check for an intraabdominal testis. Less than 50% of the times, a viable testis will be found on laparoscopy, with almost all the rest of the times finding a nubbin on the scrotum. The majority of patients undergo unnecessary laparoscopy when following this approach.
An alternative approach is looking for the nubbin first on the scrotum. If a nubbin is not found, laparoscopy is done. If a 2 stage orchiopexy is preferred, the scrotal incision would have been done unnecessarily, but not with a one stage orchiopexy
For a more scientific comparison of these options, read this abstract written by W. Snodgrass.
There is one extra middle of the way road: if contralateral testicular hypertrophy is present a scrotal exploration is done first. If not, laparoscopy is done first. Contralateral testicular hypertrophy is considered to be present if the testis is longer than 2 cm. After a few years of practice, you don’t have to measure to diagnose hypertrophy as your hands can tell right away.
Scrotal exploration and removal of testicular nubbin
The surgery is done through a 1.5-2 cm long upper/middle scrotal incision. Almost always the nubbin is found within seconds of the incision:
Sometimes retractors are needed. If a nubbin is not found within a minute it is probably not there. However, it’s worth looking longer as every now and then intraabdominal testis are able to be pulled into the groin through the scrotum.