Keywords Lymphadenectomy - lymphocele - obturator - prostatectomy - robot-assisted
Introduction
Postoperative obturator nerve injury is uncommon after robot-assisted radical prostatectomy
and lymphadenectomy. The injury of the nerve may be due to stretching, transection,
or compression. These patients typically present with sensory deficit in the upper
medial thigh, neuropathic pain in the groin and upper medial thigh, and motor weakness
in the thigh flexion and adduction. The majority of postoperative injuries may resolve
within a few weeks unless complete transection has occurred. In the case of nerve
compression through a pelvic fluid collection, an early evacuation is the cornerstone
of the management to relief symptoms. We describe a case of postoperative obturator
injury secondary to postoperative compressing bilateral pelvic lymphoceles.
Case Report
A 61-year-old male with a clinical stage T2c prostatic carcinoma underwent an uncomplicated
robot-assisted radical prostatectomy with bilateral dissection of the obturator and
iliac lymph nodes. In the 1st postoperative week, the patient recovered well from
the surgery and was discharged home. One the day after discharge, he complained of
bilateral groin and thigh discomfort. These complaints have worsened over the day,
so that he decided to seek medical care. The patient presented in an urological emergency
department. Since there was no documented obturator nerve injury in the operation
report and in the short postoperative period, it was initially postulated that these
complaints are not due to a postoperative complication. The patient was reassured
and discharged with pain medications. However, the patient continued to have complaints,
the ability to walk has worsened in the next few days, and he presented in our general
surgical emergency department after another 1 week. It has been noted that the patient
demonstrated bilateral proximal leg weakness and an inability to flex and adduct his
thighs. Because of this clinical scenario, a computed tomography (CT) scan of the
abdomen and pelvis was performed, which showed bilateral hypodense collections directly
medial to the internal obturator muscles with a thin membrane (3 cm × 5 cm [right],
4 cm × 4.5 cm [left]). See [Figure 1 ] and [Figure 2 ]. This finding was consistent with large postoperative lymphoceles involving the
obturator fossa bilaterally. Neurology was consulted and agreed with the diagnosis
of obturator nerve compression. A percutaneous drainage was indicated. Clear fluid
was evacuated from the bilateral obturator fossae. The patient had an immediate improvement
in his neurologic symptoms, regaining his normal motor strength within few weeks.{Figure
1}{Figure 2}
Figure 1: Computed tomography scan showing bilateral pelvic lymphoceles in
the obturator fossae (coronal image)
Figure 2: Computed tomography scan showing bilateral pelvic lymphoceles in
the obturator fossae (axial image)
Discussion
Obturator nerve injuries are serious complications after robot-assisted radical prostatectomy
and lymphadenectomy and may affect the neurological outcome. Clinicians usually attribute
most neuropathies present in the late postoperative period not to postoperative complications.
This resulted in a delay in the diagnosis and management in our case because our patient
developed signs of obturator neurapraxia firstly 1 week after surgery. CT scan showed
bilateral pelvic collections, indicative of bilateral deep pelvic lymphoceles compressing
the obturator nerves. After the pelvic lymphoceles were evacuated, the patient regained
his lower motor and sensory functions. A prospective cohort study of 521 patients
who underwent a robot-assisted radical prostatectomy and extended lymphadenectomy
for prostatic cancer showed a 2.5% incidence of postsurgical symptomatic pelvic lymphoceles.[1 ]
An important risk factor that may contribute to the formation of the postsurgical
lymphoceles is the disruption of lymphatics which occurs with the more extended lymphadenectomy
and in the case of nonjudicious use of electrocautery in the dissection. Other less
important risk factors are the neoadjuvant radiotherapy and the application of subcutaneous
heparin.[2 ] Several studies compared open, laparoscopic, and robot-assisted prostatectomy and
lymphadenectomy regarding the incidence of postsurgical lymphocele. In one study,
symptomatic postsurgical lymphoceles were found in 2.3% of open prostatectomy and
lymphadenectomy patients and in none of laparoscopic prostatectomy and lymphadenectomy
patients.[3 ] Another comparison of open and robot-assisted prostatectomy and lymphadenectomy
found no difference in the incidence rate of symptomatic lymphoceles, including 2.5%
and 2%, respectively.[4 ]
Two studies comparing laparoscopic versus robot-assisted prostatectomy and lymphadenectomy
showed an incidence of postsurgical lymphoceles of 0.15% and 0.13%, respectively.[5 ],[6 ]
Conclusion
Although uncommon, delayed neurologic complications after robot-assisted radical prostatectomy
and lymphadenectomy could be a result of insidious postoperative fluid collections.
Postoperative collections compressing the obturator nerve should immediately be recognized
and evacuated to improve the neurological outcome.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form the patient(s) has/have given his/her/their consent for his/her/their
images and other clinical information to be reported in the journal. The patients
understand that their names and initials will not be published and due efforts will
be made to conceal their identity, but anonymity cannot be guaranteed.
