Robot-assisted laparoscopic prostatectomy (RALP)is the most frequent strategy used for the surgical remedy of patients with localized prostate cancer. Although there is awareness about potential patient positioning nerve injuries, iatrogenic nerve lesions are less described in the literature . Here, we report 3 cases of patients who presented with neuropathic painful complications due to RALP-associated nerve lesions.
A 62-year-old patient (case 1), a 72-year-old male (case 2), and a 57-year-old patient (case 3) presented at the clinic with symptoms of neuropathic pain after RALP surgery.
Patients were diagnosed with a potential injury of different branches of the pudendal nerve (cases 1 and 2), and left obturator nerve (case 3).
Patients underwent multimodal pharmacologic treatment through pregabalin, weak opioids, strong opioid, paracetamol, and adjuvants. In cases 2 and 3, a multidisciplinary approach was needed. As the patients responded to conservative treatment, invasive approaches were not necessary.
After treatment, the patients of case 1 showed pain relief after 4 days, paresthesia resolved in 15 days, whereas the anal crushing sensation lasted for approximately 1 month. In case 2, after 4 weeks of treatment, the patient experienced a considerable decrement in pain intensity with complete response after 4 months. In case 3, pain relief was achieved after 2 days, motor symptoms recovery after 2 weeks, and neuropathic features resolved completely after 5 weeks although the obturator sign resolved within 2 months.
During RALP surgery, a wide range of surgical injury to the pelvic nerves may occur. The pathophysiology of these damages recognizes different mechanisms such as compression (e.g., due to hematoma or pelvic lymphoceles), transection, incision, traction, thermal injuries, entrapment with clips.
The evaluation of possible risk factors is of fundamental importance both for the prevention of complications and for their rapid identification and treatment [3-6]. In case 1, the damage to the inferior rectal nerve occurred for thermal injury or traction on straight during the preparation procedure of the backplane, or during Rocco stitch. The complication was probably also related to the extent of prostatic pathology, as reported by the definitive histologic examination. The extent of the pathology, therefore, was certainly a major risk factor. Concerning the mechanism of neuropathy responsible for the clinical picture described in the second case, it can be explained as a possible injury occurred during the running stitch and the additional suture of Santorini plexus. The bilateral nerve damage may explain the severity of the neuropathic painful condition, whereas the presence of a particularly represented plexus and a connective tissue at the pubic symphysis represented a considerable risk factor. Case 3 regards a lesion of the left obturator nerve. This nerve originates from the ventral rami of the 2nd, 3rd, and 4th lumbar nerve roots. It follows the iliopectineal line into the lesser pelvis, runs along the lateral pelvic wall and then enters into the obturator foramen via the obturator canal. Within the canal, the nerve divides into an anterior branch, posterior branch, and a branch to the external obturator muscle then. Then, it exits through the obturator tunnel and enters the thigh. The sensory distribution of the nerve encompasses the anteromedial hip joint, the medial knee joint, and the skin on the inner thigh just above the medial knee from the anterior branch. The obturator nerve injury is described as a rare complication of robotic-assisted PLND. Because the obturator nerve can be adherent to lymph nodes or enclosed by them, a careful nerve mobilization should be performed, and fixed lymph nodes should not be mobilized roughly. Specifically, the proximal part of the obturator nerve runs closely the external iliac vein and the internal iliac artery. This is the location of the internal iliac lymph nodes. In our case, we suppose that the nerve damage was caused during the extensive PLND through a thermal injury of the nerve at the entrance of the obturator fossa . Alternatively, a compressive effect on the nerve was produced by a PLND-induced lymphocele. The combination of both mechanisms seems to be another plausible explanation. According to this latter hypothesis, the early multimodal pain strategy and antiedematous therapy may explain the rapid resolution of the clinical picture [7-8].
Several suggestions focused on improving surgical technique and aimed at avoiding neurologic complications can be proposed. Firstly, the thermal energy should be minimized by using bipolar output energy <35 and <50 W in monopolar. Furthermore, hemostasis through microsutures (e.g., 4-0 brainded absorbable suture CV-25 TAPER 1/2 circle 17 mm Polysorb; Covidien) can represent a less invasive approach. Other suggestions concern the use of titanium clip during dissection, Rocco stitch (e.g., 3-0 V-Loc barbed absorbable suture GU-46 TAPER 5/8 circle 27 mm; Covidien) performed not through full-thickness modality. Finally, because the different branches of the pudendal nerve run laterally and dorsal to the rectum it should be recommended to minimize traction maneuvers during the procedure of prostate detachment.
The RALP-associated neurologic injuries may occur even when performed by highly experienced surgeons. A better understanding of the potential iatrogenic nerve lesions can surely allow an improvement in the surgical technique. A multidisciplinary approach and early multimodal pain strategy are mandatory for managing these complications.
1. Du Y, Long Q, Guan B, et al. Robot-assisted radical prostatectomy is more beneficial for prostate cancer patients: a system review and meta-analysis. Med Sci Monit 2018;24:272–87
2. Ahmed F, Rhee J, Sutherland D, et al. Surgical complications after robot-assisted laparoscopic radical prostatectomy: the initial 1000 cases stratified by the Clavien classification system. J Endourol 2012;26:135–9.
3. Novara G, Ficarra V, D’Elia C, et al. Prospective evaluation with standardised criteria for postoperative complications after robotic-assisted laparoscopic radical prostatectomy. Eur Urol 2010;57:363–70
4. Ou YC, Yang CR, Wang J, et al. The learning curve for reducing complications of robotic-assisted laparoscopic radical prostatectomy by a single surgeon. BJU Int 2011;108:420–5.
5. Ou YC, Yang CK, Chang KS, et al. Prevention and management of complications during robotic-assisted laparoscopic radical prostatectomy following comprehensive planning: a large series involving a single surgeon. Anticancer Res 2016;36:1991–8.
6. Murphy DG, Bjartell A, Ficarra V, et al. Downsides of robot-assisted laparoscopic radical prostatectomy: limitations and complications. Eur Urol 2010;57:735–46.
7. Maerz DA, Beck LN, Sim AJ, et al. Complications of robotic-assisted laparoscopic surgery distant from the surgical site. Br J Anaesth 2017;118:492–503.