Combined robotic inguinal and iliac‐obturator lymphadenectomy for stage III skin cancers: Surgical technique and preliminary results

Abstract Background Ilio‐inguinal lymphadenectomy for stage III melanoma and skin cancers still represents the best therapeutic option for a subset of patients, although the incidence of post‐operative complications is dramatically high. Only a paucity of papers on robotic approach have been published, reporting experiences on isolated pelvic or inguinal lymphadenectomy, and no series on combined dissections have been described yet. We present the preliminary results achieved with combined robotic approach, with special emphasis on lymph nodal mapping, dissection technique and postoperative complications linked with the lymphatic system. Methods Between September 2019 and September 2021, 10 patients were submitted to robotic inguinal and iliac‐obturator lymphadenectomy. Results Post‐operative course was characterised by early mobilisation and minimal post‐operative pain. Only one lymphoedema occurred and lymph nodal harvesting was more than satisfactory. Conclusions Robotic surgery provides meticulous lymph nodal dissections, with promising functional and oncologic outcomes. Further series are advocated to confirm these preliminary results.

particular, ilio-inguinal dissection is historically associated with wound complications, lymphatic fistulas, seroma/lymphocele formation and chronic lymphoedema, with prolonged in-hospital stay and severe impairment in quality of life. [3][4][5] In order to overcome these criticisms, novel minimally invasive alternatives to the conventional open approach have been introduced, including videoscopic inguinal and iliac-obturator lymphadenectomy (VIIOL), alone or in combination. [4][5][6][7] As discussed in our single-institution experience, a combined VIIOL minimises surgical morbidity and accelerates recovery of daily activities, maintaining appropriate oncologic outcomes. 6 With the effort to improve stage III melanoma and more generally stage III skin cancers oncological care, a paucity of papers on robotic approach have been recently published, but the reported experiences only concern isolated pelvic 8-11 or inguinal dissections. 12 As far as we know, no series on combined robotic inguinal and iliacobturator lymphadenectomy (RIIOL) have been described yet.
We present the surgical technique and related outcomes of RIIOL for stage III skin cancers, deepening current and perspective applications of this innovative technique, with special emphasis on lymph nodal dissection technique enhanced by high-resolution images magnification and Indocyanine-green (ICG) real-time fluorescent technology application, weapons to accurately evaluate lymphatic mapping and eventual lymphatic leak, possibly reducing postoperative complications linked with the lymphatic system. Intra-and postoperative outcomes have also been collected, including type of surgery and surgical technique adopted, operative duration, hospital stay, length of drain placement and volumes of drainages and complication rate according to Clavien-Dindo Classification, 13 particularly focussing on lymphoedema occurrence. Limb circumference measurements to assess postoperative lymphoedema were performed for both legs preoperatively, and then patients were followed up at 1, 3 and 6 months after surgery. According to our Institutional protocol for lymphoedema recognition, measurements were done at the superior border of the patella, 10 cm above and below the superior border of the patella, at the ankle and at the dorsum of the foot. 14 The study was approved by the Institutional Ethical Review

| OPERATIVE TECHNIQUE
The night before surgery every patient receives subcutaneous low molecular weight heparin (dosage according to the weight), that will be taken for another 30 days. At the time of surgery, patients wear compression stockings, kept until a normal deambulation has been restored. Two grams of prophylactic ev Cefazolin are administrated and urinary catheter is placed.
Combined pelvic and inguinal robotic technique includes two surgical steps: the abdominal time for iliac-obturator LNs dissection, and the inguinal time for inguinal LNs dissection. The procedure is borrowed from the laparoscopic approach we already described. 6 Briefly, under general anaesthesia, the patient is placed in the supine position with the pelvis slightly extended on a split-leg table tilted 30°up on the side to treat, in head-down position.  Patients' characteristics data are summarised in Table 1.

| Inguinal step
Only one patient submitted to RIIOL developed a Grade II complication according to Clavien-Dindo Classification, 13   laparoscopic experience of 302 min. 6 However double robotic docking is time-consuming di per se, and since this cohort comprehends patients operated during our learning curve period, a shortening in surgery duration is expected. Indeed, as we previously reported in our experience with combined VIIOL, 6 even with the robotic approach we assumed that a combined procedure can emerge the advantages of the two separate surgeries, pelvic and inguinal.
Length of hospital stay is 2 days, comparable with videoscopic procedure. 6 The most relevant difference from videoscopy has been a further reduction of post-operative pain, managed with paracetamol only, administered when necessary by the first post-operative day.
Our preliminary experience with combined RIIOL is still limited and the follow-up restricted, therefore we can't still draw firm conclusions, but as for other surgical procedures, robotic approach seems to be a promising weapon in managing stage III skin cancers, allowing meticulous lymph nodal dissections, with promising functional and oncologic results.
Further investigations on larger series are advocated to confirm these preliminary findings.

ACKNOWLEDGEMENT
No financial support has been used.

CONFLICT OF INTEREST
The Authors have no conflict of interest to declare.

DATA AVAILABILITY STATEMENT
The data supporting the findings of this study are available from the corresponding author upon reasonable request.