Robotic-assisted microsurgery in andrology: a systematic review

Robot-assisted microsurgical vasovasostomy and vasoepididymostomy

Obstructive azoospermia is defined as the absence of spermatozoa in the sediment of a centrifuged sample of ejaculate due to obstruction.2,18 It accounts for 20%–40% of patients with azoospermia.19 Obstruction can be congenital (i.e., congenital bilateral absence of the vas deferens, idiopathic epididymal obstruction, etc.) or acquired (vasectomy, infection, trauma, iatrogenic injury, etc.).20 Treatment options are (1) MVV or microsurgical vasoepididymostomy (MVE) for epididymal or vasal obstruction, respectively (in case the female partner’s ovarian reserve is good), or (2) sperm retrieval techniques in all other cases.2 The patency rates of MVV and MVE are 99% and 65%, respectively.21 However, these procedures are technically challenging, as they demand manual dexterity, steadiness of movement and coordination,22 along with a skilled microsurgical assistant.

Robot-assisted microsurgery was introduced to overcome these challenges. Initial reports included ex vivo and animal models. These reports highlighted a short learning curve with an easy transition for microsurgeons, significantly less operation time, and less formation of sperm granuloma on the vasovasostomy anastomosis site than conventional microsurgery. Furthermore, the elimination of hand tremors and excellent patency rates was observed.11,12,23,24

Fleming first reported RAVV in two cases of bilateral robot-assisted vasovasostomies.13 The author reported the elimination of normal physiological hand tremor, a greater ease and precision of suture placement, a shorter learning curve than microsurgical techniques and excellent patency results.13 In 2007, De Naeyer et al.25 reported a case of robot-assisted vasectomy reversal without intraoperative problems (no loose stitches, no broken sutures, etc.) or postoperative complications. In the 3-month follow-up period, semen analysis showed 120×106 viable spermatozoa per ml, which confirmed patency.

Parekattil et al.26 reported their first cases in 2009, with excellent results for the RAVV group, even in patients with many years (7, 18, and 19 years) postvasectomy. The same group compared, in 2010, 20 RAVV and 7 MVV cases performed by a single microsurgeon.27 The operation time for RAVV decreased significantly after the first nine cases (150–180 min to 65–120 min). The authors also highlighted the significant (P = 0.04) improvement in early semen analysis and decrease in the mean operative time with the assistance of the Da Vinci® robotic system.27

Parekattil and Brahmbhatt followed with a prospective control study of a clinical database, with 123 patients undergoing vasectomy reversal (78 of robot assisted and 45 of microsurgery).28 Thirty of these cases were robot-assisted vasoepididymostomies (RAVE), and seventeen were MVE. The operative time was significantly shorter for both RAVV and RAVE than MVV and MVE. The setup time for the robot, after a certain number of cases, was comparable to that of the microscope. The need for a skilled microsurgical assistant was eradicated because the surgeon could utilize the additional robotic arm.28

The same group reported similar results in another study comparing robotic and microsurgical vasectomy reversal. They documented a significant difference in operation time for both vasovasostomy (97 min vs 120 min, P = 0.0003) and vasoepididymostomy (120 min vs 150 min, P = 0.0008) in favor of robotic assistance. A significant difference was reported for postoperative sperm count recovery but not for the mean postoperative total mobile sperm count. Patency rates were significantly greater for RAVV (96% vs 80%, P = 0.002). Pregnancy rates 1 year after surgery were 65% for the RAVV group and 55% for the MVV group.29 Gudeloglu et al.30 and Kavoussi31 reported similar results. In addition, Gudeloglu et al.30 reported 55% patency rates after RAVE. It should be noted that patency rates for MVE range from 39% to 92%. The level at which MVE is performed and the technical experience of the surgeons are two major factors for its success.32,33

Santomauro et al.34 performed robotic vasovasostomy using both one-layer and two-layer techniques. The anastomosis was performed by experienced staff on one side, followed by the resident on the opposite side. There was no statistically significant difference in the mean operation time between the two groups (37.6 min for experienced surgeons and 54 min for residents, P = 0.13). Twelve of the 13 patients were patent (92.3%) in the follow-up (as evidenced by sperm in the ejaculate). That study showed the feasibility and effectiveness of the one-layer technique, along with a relatively fast learning curve.34 Furthermore, in 2017, Marshall et al.35 reported similar results for single-layer RAVV. Sixty patients underwent single-layer anastomosis. Eighty-eight percent of anastomoses were patent, and 11% of operations (7/60) had low-grade complications.

Furthermore, robotic-assisted microsurgery enables the surgeon to operate in body locations that are difficult to access with open microsurgery. Trost et al.36 reported the first intracorporeal RAVV for the treatment of a patient with vasal obstruction following bilateral inguinal hernia repair with mesh placement. Robotic assistance helped surgeons bypass fibrotic changes that developed in the inguinal canal after herniorrhaphy. In addition, through RAVV, surgeons were able to perform minimal incisions instead of the standard extended bilateral inguinal incisions required for this procedure.36 Another novel application of RAVV was described by Barazani et al.,37 who performed intra-abdominal RAVV in a case of obstructive azoospermia following laparoscopic vasectomy. Robot-assisted laparoscopy was used for the mobilization of the vas deferens and robotic microsurgery for vasovasostomy.

Finally, Brahmbhatt et al.38 evaluated the use of RAVV for postvasectomy pain syndrome (PVPS). The group used a pain impact questionnaire (PIQ-6; range: 40–78) and visual analog pain scale (VAPS; range: 0–10) to assess the pain. They performed 22 RAVV and 2 RAVE procedures for PVPS. The patency rate was 94.1% (16 of 17 patients), and improvement in the PIQ-6 score was found in 85.0% (17 of 20 patients), with a mean follow-up of 4.5 (standard deviation [s.d.]: 0.6) months. A significant decrease was found in PIQ-6 and VAPS scores immediately after surgery and at the 6-month follow-up.38 This study shows that RAVV is a possible technique for PVPS management. A summary of the studies referring to robotic-assisted vasovasostomy is provided in Table 2.

Robot-assisted microsurgical varicocelectomy

Varicocele is considered a major factor of male infertility. A 1992 study showed a clear association between varicocele and impairment in testicular function.39 Varicocelectomy leads to significant improvements in semen parameters, regardless of the surgical technique applied, as shown in a 2007 meta-analysis.40 Çayan et al.41 compared various treatment approaches for varicocele repair in 2009. They concluded that the microsurgical subinguinal approach (MVx) has higher spontaneous pregnancy rates, fewer recurrences, and lower complication rates than other techniques.

The first varicocelectomy performed with the assistance of the Da Vinci® robotic system was performed by Corcione et al.42 in 2004. They performed two robot-assisted laparoscopic intra-abdominal varicocelectomies among 32 various robot-assisted laparoscopic procedures in an effort to report preliminary data about the advantages and limitations of robot-assisted laparoscopy. Shu et al.14 first described robot-assisted microsurgical inguinal varicocelectomy (RAVx) in 2008. The group compared it with microsurgical varicocelectomy. No significant differences were found in operating time (even with their limited experience in RAVx). They also described the elimination of hand tremors as an advantage of RAVx.14

Parekattil and Brahmbhatt28 performed a prospective randomized controlled trial of microsurgery versus robotic-assisted subinguinal varicocelectomy in a canine model. Significant differences were found in operation times (per side) in favor of RAVx (9.5 min vs 12 min, P = 0.04). The robot and microscope setup times were comparable. No vessel injuries or knot failures were reported. The same group published five updates of reviews of their prospective clinical database. Patients treated with varicocelectomy were men with grade two or three varicocele and one of the following: (1) azoospermia, (2) oligospermia, or (3) chronic orchialgia with or without oligospermia who failed all conservative management options. The median operation time was gradually shorter after the initial case, with 20 min reported in their fourth (181 cases) and fifth (238 cases) updates.10,15,28,30,43,44 The median follow-up was 22 (range: 1–48) months, as stated in the fourth paper. The percentage of oligospermic men with significant improvement in sperm parameters (count and/or motility) was 75%–77% in all studies, even in the initial cases. Twenty-eight percent of patients with azoospermia presented with oligospermia after repair. Ninety-two percents of patients who underwent RAVx for testicular pain (along with robotic denervation of the spermatic cord in some cases) presented a significant reduction in pain. Only three complications occurred after 181 procedures, two scrotal hematomas and one hydrocele, both being treated conservatively. Only two varicocele recurrences or persistence were reported.10,15,28,30,43,44 Furthermore, the same group published the results of RAVx in addition to robot-assisted microsurgical denervation of the spermatic cord in 319 patients with varicocele and orchialgia. Improved sperm parameters were found in 65% of patients, and a significant reduction in pain was reported by 73% of them.45 The above studies indicate the feasibility, efficacy, and safety of robot-assisted microsurgical subinguinal varicocelectomy.

McCullough et al.46 published a retrospective review of 258 RAVx procedures (in 140 patients), reporting the effect of RAVx on semen parameters and testosterone levels. The (mean ± s.d.) operative time per side was 49 ± 13 min for robotic varicocelectomy and 57 ± 16 min for microsurgical varicocelectomy. A learning curve was reached after 15 cases. A statistically significant increase was observed in the median total and free testosterone levels (P < 0.0001), median sperm concentration (P < 0.03), and median testicular volume at the 3-month follow-up (P < 0.0006 for right testicle volume and P < 0.0001 for left testicle volume). Recurrence of varicocele was reported in 9.6% of cases, higher than that in previous reports. The authors noticed that this higher recurrence was due to the way they defined recurrence (any measurable postoperative retrograde flow).46 A summary of the studies referring to robotic-assisted varicocelectomy is provided in Table 3.

Robot-assisted microsurgical denervation of the spermatic cord

Chronic orchialgia is intermittent or constant, unilateral or bilateral testicular pain that significantly interferes with patients’ daily activities and lasts more than 3 months.47 This pain may involve the epididymis, paratesticular structures, and the spermatic cord.48 Etiological factors include trauma, infection, hydrocele, torsion, varicocele, vasectomy, and hernia repair. In almost 25% of patients, no etiological factor can be found (idiopathic).47,49,50 First-line treatment consists of a combination of antibiotics, analgesics, and anti-inflammatory drugs. Surgical treatment is indicated after conservative management has failed. Microsurgical denervation of the spermatic cord (MDSC) has emerged as the treatment of choice over orchiectomy and epididymectomy. MDSCs allow testicular preservation and offer high success rates.51,52 Furthermore, Parekattil et al.53 identified Wallerian degeneration in nerve bundles located at the cremaster muscle, perivasal, and periarterial/lipomatous area tissues. These findings help to minimize the ligation area and preserve the bulk of the spermatic cord without compromising MDSC efficacy.

Parekattil et al.10,15 developed a targeted approach involving robot-assisted microsurgical denervation of the spermatic cord (RMDSC). They have published seven updates of their results (Table 4).10,15,28,30,43,54,55 Patient selection criteria were chronic testicular pain (>6 months), failure of conservative pain management treatments, no findings on neurologic and urologic workup, and complete temporary resolution of pain after spermatic cord block with local anesthetic agents. In the latest published report of their clinical database, the group reviewed 860 RMDSC cases (October 2008–July 2016). The median robotic console time was 20 (range: 15–80) min. Complete resolution of pain was achieved in 462 cases (49%), and a decrease above 50% (using PIQ-6 and VAS scores) was achieved in 292 (34%) cases. In 142 (17%) patients, the pain persisted. A remarkable finding was a significant reduction in pain at follow-up (67% of patients at 6 months, 68% at 1 year, 77% at 2 years, 86% at 3 years, and 83% at 4 years). The median operative time was 41 min and 37 min for the initial cases and decreased to 20 min in the final update. Complete resolution of pain was significantly lower in the final update (49%) than in previous reports (70.5%–75%). The complications were 2 cases of testicular artery injury, 1 case of testicular ischemia, 1 case of vasal injury, 4 cases of seroma, 23 cases of hematoma, 24 cases of wound infection and dehiscence, 2 cases of penile swelling/pain, 1 case of pulmonary embolus, 1 case of hydrocele, 1 case of urinary retention, 1 case of port site pain, 1 case of referred leg pain, and 1 case of port site bleeding. Testicular artery injuries were identified and repaired intraoperatively, with no long-term testicular atrophy identified. Testicular ischemia was noted in a case with multiple previous pelvic and groin injuries and surgeries. The work of this group10,15,28,30,43,54,55 illustrates the feasibility and effectiveness of targeted RMDSCs in the treatment of chronic testicular and scrotal pain.

In addition, Parekattil and Cohen43 performed robotic microsurgical ligation of the genitofemoral and inferior hypogastric nerve fibers above the internal inguinal ring in 30 patients with persistent pain after microsurgical denervation of the spermatic cord and patients with phantom groin pain following orchiectomy. The operation was performed using an abdominal approach, and five of the cases were conducted using a single-port approach. Pain was eliminated in 60% (18/30) of the cases and was reduced by more than 50% in 13% (4/30) after 1 month of follow-up. The mean operative time was 10 (range: 5–30) min.

Robot-assisted microscopic testicular sperm extraction

Nonobstructive azoospermia (NOA) is the absence of sperm in a semen analysis after centrifugation in at least two consecutive sperm analyses.56 NOA is caused by primary testicular dysfunction or dysfunction of the hypothalamus–pituitary–gonadal axis. Sperm retrieval is considered in men who are candidates for assisted reproductive technology (ART) protocols. The gold standard surgical approach is testicular sperm extraction (TESE).2 Microsurgical TESE (mTESE) is performed under a surgical microscope and has 1.5 higher retrieval rates than conventional TESE.57

When conducting our search, only two references regarding robot-assisted TESE (ROTESE) were published, one of which was an animal model study. In the animal model study, ROTESE appeared comparable to open TESE in color spot detection (canine testicles were injected with different color dye spots at random locations).28 Parekattil and Gudeloglu10 performed 12 ROTESE procedures between 2009 and 2012 without any reported complications. The authors reported that tissue handling and dissection were slightly easier and ergonomic with robotic assistance.