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ABSTRACT

Purpose: Robot assisted surgeries for head and neck cancers are still at a nascent stage in many countries. A robot-assisted neck dissection (RAND) performed via a scar in concealed areas can be a potential game changer in treatment of early oral cancers and effectively alleviate cosmetic concerns of patients with satisfactory oncological outcomes. However, it is yet to gain increased acceptance amongst clinicians due to concerns relating to its oncological safety, cost effectiveness, lack of commensurate awareness and expertise at the practitioner level.Materials and Methods: This study is a comparative analysis of RAND and conventional neck dissection done at a tertiary care cancer centre from July 2017 to January 2020. 41 Patients treated with upfront surgery for oral and oropharyngeal malignancy were included in the study. The parameters analysed include age, gender, site of the tumour, type and extent of neck dissection, lymph node yield, type of reconstruction, cost of hospitalization, and complications. All statistical analyses were performed using SPSS version 20.0.Results: The rate of marginal mandibular nerve paresis/palsy and shoulder dysfunction was higher in the robotic neck dissection group (P=0.11, relative risk [RR]=7.33, 95% confidence interval [CI]=0.40–133.58 and P=0.23, RR=5.24, 95% CI=0.27–102.81, respectively). The remaining parameters showed comparable outcome with no statistical significance between the groups.Conclusions: Although the functional and oncological outcomes of RAND are comparable with open surgeries, there exists a definitive learning curve. RAND is a feasible alternative that can be offered to individuals requiring a concealed scar/incision at a justifiable additional cost.

Keywords: Robot-assisted neck dissection; Head and neck oncosurgery; Head and neck cancer; Robotic surgery

INTRODUCTION

Oral cancer ranks among the top 3 most common cancers in the Indian subcontinent, with a steady rise in its incidence among young and urban populations [1,2]. Robot-assisted surgeries for head and neck cancers are still at a nascent stage in countries such as ours. Given the ongoing technological advances in head and neck onco-surgeries, patients

Ann Robot Innov Surg. 2021 Nov;2(2):40-48https://doi.org/10.37007/aris.2021.2.2.40pISSN 2635-6678·eISSN 2635-666X

Original Article

Received: Jun 22, 2021Revised: Oct 4, 2021Accepted: Oct 15, 2021

Correspondence toVishal Rao U SDepartment of Head and Neck Surgical Oncology, Health Care Global Enterprises Ltd., P. Kalinga Rao Road, Sampangi Ram Nagar, Bangalore 560027, India.E-mail: drvishal.rao@hcgel.com

Copyright © 2021 The Korean Association of Robotic SurgeonsThis is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ORCID iDsN Apoorva Reddy https://orcid.org/0000-0002-5706-086XShalini Thakur https://orcid.org/0000-0002-1621-0868Anand Subash https://orcid.org/0000-0003-2645-0694Akshay Kudpaje https://orcid.org/0000-0002-6987-9303Vishal Rao U S https://orcid.org/0000-0001-6167-5114

Conflict of InterestNo potential conflict of interest relevant to this article was reported.

Author ContributionsConceptualization: Reddy NA, U S VR; Data

N Apoorva Reddy , Joshna B M, Shalini Thakur , Shameekcha Mishra, Anand Subash , Akshay Kudpaje , Vishal Rao U S

Department of Head and Neck Surgical Oncology, Health Care Global Enterprises Ltd., Bangalore, India

Robot-assisted Neck Dissection in Head and Neck Malignancy: a Study Conducted at a Tertiary Care Cancer Center

curation: Reddy NA, B M J, Mishra S; Formal analysis: Reddy NA; Investigation: Reddy NA; Methodology: Reddy NA, B M J, Thakur S, Subash A, Kudpaje A, U S VR; Resources: U S VR; Supervision: Thakur S, Kudpaje A, U S VR; Writing - original draft: Reddy NA; Writing - review & editing: Thakur S, Subash A.

are increasingly expecting better surgical outcomes. Amid the mounting evidence of treatment-related psychosocial distress and its monumental impact on quality of life, social life, and occupational well-being [3], surgeons and patients are constantly looking for a surgical technology that offers superior cosmesis, enhanced visualization, and precision. Furthermore, the presence of a visible scar on the neck in early head and neck tumors amenable to transoral excision is often a significant cause for concern among patients. A robot-assisted neck dissection (RAND) performed via a scar in the concealed areas can effectively alleviate such concerns with satisfactory oncological outcomes. RAND could be a potential game-changer in the treatment of these early oral cancers. However, it is yet to gain increased acceptance among clinicians due to concerns relating to its oncological safety, cost-effectiveness, lack of commensurate awareness, and expertise at the practitioner level.

This study is a comparative analysis of RAND and conventional neck dissection done at a tertiary care cancer center in India. Our study attempts to assess oncological safety as well as functional outcomes of RAND. Other aspects like feasibility of free flap reconstruction, duration of hospital stay, cost, and complications are also emphasized.

MATERIALS AND METHODS

This is a comparative retrospective study done at HCG Cancer Centre, Bangalore. The Institutional Review Board and ethics committee approved the study. Medical records of patients with oral and oropharyngeal malignancy treated at our center from July 2017 to January 2020 were extracted. All the patients had a minimum follow-up of 1 year. Patients treated with upfront surgery were included in the study. Patients with adequate mouth opening, a primary tumor that could be oncologically resected transorally, or with combined transoral and retroauricular neck access were selected for RAND. The parameters analyzed include age, sex, tumor site, type and extent of neck dissection, lymph node yield, type of reconstruction, cost of hospitalization, and complications.

Patient counseling and peri-operative planningAfter obtaining consent for surgery, patients were thoroughly evaluated and counseled at length regarding the type of procedure, cost associated with the surgery, and the conversion to open surgery if needed. Patients were duly informed that there would be no change in prognosis and oncological outcomes following RAND. In our institute, we have special informed consent for robotic surgery that is obtained prior to the procedure.

Technique of surgeryThe technique of flap elevation for RAND has been illustrated in a stepwise manner by Rao et al. [4] The key steps are highlighted below:

The operative technique involves a posterior approach with a T incision marked along the hairline, curving 5 mm along the postauricular groove. Once the fascia over the sternocleidomastoid muscle fibers is visualized, the flap is elevated till the greater auricular nerve, and external jugular vein have been identified. From this point onwards, subplatysmal elevation of the flap is carried out till the anterior belly of digastric on the opposite side, and superior belly of omohyoid on the side of dissection is identified. Once the skin flaps are adequately raised, an indigenously manufactured retraction system for neck dissection (RaVi retractor) is used to lift the skin flaps, keep them apart and create adequate space for robotic

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instrumentation. The robot is docked in place at a 45-degree angle to the operating table stem, which is rotated to create space for the robotic legs. The 3 robotic arms are oriented in a triangular fashion to avoid instrument clashes, with the camera arm forming the apex and 2 instrument arms forming the base of the triangle (Fig. 1). The camera used is a 0-degree endoscope, with an 8 mm monopolar scissors in arm one and an 8 mm fenestrated bipolar forceps in arm 2. As there is no haptic feedback appreciable from the robotic arms, we mark the lower border of the mandible to assist in the identification of the marginal mandibular nerve. The nerve is identified using the facial vessels and the lower border of the mandible as landmarks. The further steps of submandibular dissection are similar to the conventional technique. An attempt is made to preserve a reasonable length of the facial artery for microvascular anastomosis. Robotic instruments are used to gain adequate exposure for clearance of the submental level Ib lymph nodes. The lateral neck dissection (II–IV) is addressed after the clearance of levels 1a and 1b.

We use 2 approaches for lateral dissection in RAND: an anterior approach and posterior approach. The posterior approach involves starting the neck dissection from level V, identifying the spinal accessory nerve, skeletonizing the sternocleidomastoid muscle, and proceeding with the level II–IV dissection. The anterior approach involves identification of the anterior border of sternocleidomastoid and, using robotic instruments, proceeding with level II–IV like the conventional technique in a lateral to medial direction.

Statistical analysisDescriptive statistics such as the mean, standard deviation, and percentage were used to present the data. Categorical variables were compared using the χ2 test or Fisher's exact test for small samples. Continuous variables were compared using the t-test or Mann-Whitney U test. All statistical analyses were performed using SPSS version 20.0. A P-value of <0.05 was considered statistically significant.

RESULTS

DemographicsA total of 41 patients were included in the final analysis. Of these, 20 patients underwent RAND, and 21 underwent conventional neck dissection (Table 1). The age of the patients ranged from 23 years to 72 years, with the mean age being lower (47.2±12.4) in the RAND

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Robotic arms in action clearing level Ia and Ib

Fig. 1. Three robotic arms oriented in a triangular fashion.

group (P=0.01). There was no significant difference noted with respect to the sex of the patients and subsite of disease (P=0.72, P=0.11). All the 21 patients in the open neck dissection group had carcinoma of the oral cavity, whereas the robotic group had 17 patients with carcinoma of the oral cavity and 3 patients with carcinoma oropharynx.

Lymph nodal yieldLymph node yield following neck dissection was tabulated for all the patients, and pathologically positive lymph nodes were grouped separately. The conventional neck dissection group had an average lymph node yield of 29.62±15.9, and the robotic group had an average yield of 26.8±11.21, with no statistical difference between them (P=0.82). The pathological nodal yield was 1.62±4.3 in the conventional group and 0.75±1.29 in the robotic group, with no statistical difference (P=0.85; Fig. 2).

ReconstructionFree flap reconstruction was used for most patients in both groups: 16 out of 21 patients in the conventional group and 15 out of 20 patients in the robotic group. The remaining patients underwent primary closure where feasible or local flap reconstruction.

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Table 1. Patient dataCharacteristics Conventional ND (n=21) RAND (n=20) P-valueAge 56.3±9.9 47.2±12.4 0.01Sex (male/female) 15/6 16/4 0.72Ca oral cavity 21 17 0.11Ca oropharynx 0 3 0.11Days of hospitalization 8.5±3.1 8.24±2.48 0.87Avg neck yield 29.62±15.9 26.8±11.21 0.82Avg patho neck yield 1.62±4.3 0.75±1.29 0.85Date of drain removal 5.76±1.97 5.65±1.31 0.78Recurrence (local) 3 5 0.69Recurrence (regional) 0 0 -Mrnd 5 5 1.00Snd 16 15 1.00Free flap for reconstruction 16 15 1.00ND = neck dissection; RAND = robot-assisted neck dissection; Ca = carcinoma; Avg = average; Mrnd = modified radical neck dissection; Snd = selective neck dissection.

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Fig. 2. Comparison of lymph node yield in robotic and non-robotic group. Avg = average.

Variable parametersThe duration of hospital stay and postoperative drain removal were comparable between both groups. The average days of hospitalization was 8.5±3.1 in the robotic group and 8.24±2.48 in the non-robotic group (P=0.87). Drain removal was done between the fourth and seventh postoperative days in the robotic group and between the fifth and ninth postoperative days in the conventional group; no statistical significance was noted between the groups (P=0.78).

ComplicationsThe relative risk was calculated for the complications following neck dissection for both groups (Table 2). The rate of seroma formation, re-exploration, hematoma formation, and flap necrosis were comparable between the 2 groups (Fig. 3). The rate of marginal mandibular nerve paresis/palsy was higher in the robotic neck dissection group (P=0.11, relative risk [RR]=7.33, 95% confidence interval [CI]=0.40–133.58). The rate of shoulder dysfunction was higher in the robotic group compared to the non-robotic group (P=0.23, RR=5.24, CI=0.27–102.81).

DISCUSSION

In 2005, the da Vinci® robot made its clinical debut in otolaryngology head and neck surgery when the first transoral robotic surgery (TORS) for tongue base neoplasm was performed [5]. Subsequently, the utilization of robotic surgery has expanded to encompass various lesions involving the oropharynx, hypopharynx, larynx and parapharyngeal space. RAND was first reported by Kang et al. [6] in a well-differentiated thyroid carcinoma with lateral

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Table 2. Comparison of complicationsComplications Conventional ND (n=21) RAND (n=20) P-value RR 95% CISeroma 3 5 0.45 1.75 0.48–6.38Re-exploration 6 4 0.72 0.70 0.23–2.12Marginal mandibularn. Palsy 0 3 0.11 7.33 0.40–133.58Hematoma 5 7 0.43 1.47 0.56–3.88Shoulder dysfunction 0 2 0.23 5.24 0.27–102.81Flap necrosis 4 5 0.72 1.31 0.41–4.20ND = neck dissection; RAND = robot-assisted neck dissection; RR = relative risk; CI = confidence interval.

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Fig. 3. Complications post surgery.

cervical node metastasis. Despite the advances in robotic surgeries, RAND in head and neck surgery is yet to gain momentum. The main attributable reasons are concerns regarding its oncological safety and cost-effectiveness. Although robotic surgery for neck dissection via modified postauricular facelift approach has been abundantly described in the literature [7-10], there is a lack of data on its postoperative outcomes, complications, and adequate oncological clearance.

Here, we describe our experience of comparative analysis between conventional and robotic neck dissection for oral cavity and oropharyngeal carcinomas. In our study, the mean age of patients undergoing robotic neck dissection was 47 years, and conventional neck dissection was 56 years. This clearly illustrated that concerns regarding scar cosmesis and functionality are increasing among patients of all ages, not just young patients.

One of the common concerns while doing a RAND is the lack of surgical exposure leading to decreased oncologic clearance. In this study, the average neck yield and pathological neck yield were comparable between both groups. A systematic review and meta-analysis on robotic neck dissection showed comparable average neck yield and pathological neck yield [11]. Our study showed similar outcomes with comparable average lymph node yield and pathological nodal yield (P>0.05).

At our institute, the average cost of surgery and hospitalization in the robotic category is INR 5.37 lac (7,359 USD), while the average cost of hospitalization for conventional approach surgery is approximately INR 4.56 lac (6,249 USD). The patients included in the robotic group willfully complied with the additional expenses so they could have a hidden concealed scar (Fig. 4).

None of the robotic neck dissection group patients were converted into open procedures as no major intraoperative complications were encountered. Also noteworthy is the feasibility of free flap reconstruction and microvascular anastomosis in RAND cases. The facial artery and internal jugular vein were used for anastomosis in the conventional group in most cases, whereas the superior thyroid artery, internal jugular vein, and external jugular vein were used

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Fig. 4. Scar of a patient who underwent robot-assisted neck dissection.

in the robotic group. The plausible explanation of this is the easy accessibility and exposure of the above-mentioned vessels during RAND.

Regarding complications, we noted a higher rate of marginal mandibular nerve paresis/palsy in about 15% of patients in the robotic group. This may be explained by the extended flap raising beyond the lower border of the mandible and excessive stretch during retraction to facilitate the reach of robotic instruments during surgery. Additionally, the facial vessels have to be meticulously dissected and preserved when microvascular reconstruction is planned. This may lead to added dissection around the nerve area. In our experience, we noted a technical difficulty in delineating marginal nerves using the robot. This can be avoided by marking the lower border of the mandible prior to commencing the neck dissection and clipping the facial vessels about 1 cm below the lower border of the mandible.

Also noted were the higher rates of shoulder dysfunction in the robotic neck dissection group, which was 9.5%. On detailed analysis, we found that this subset of patients underwent neck dissection via the posterior approach. This approach is useful in the initial stages of training but involves direct dissection over the spinal accessory nerve in the posterior triangle. Over time and with more experience, we overcame this and adapted to the anterior approach for all cases, where there is a lesser chance of damage to the spinal accessory nerve. Oncological safety was assessed, and the recurrence pattern of patients was studied. On one year follow-up, 3 patients in the robotic group and 5 in the conventional group had a locoregional recurrence in the oral cavity and oropharynx. None of the patients had positive margins during resection. Ji et al. [12] compared the functional and cosmetic outcomes of RAND with conventional neck dissection and concluded that the robotic group saw lower postoperative neck edema and sensory loss in the early postoperative period and experienced superior cosmetic satisfaction. They also reported a higher rate of transient marginal nerve palsy in the robotic group compared to the conventional group.

Since retroauricular incision was used to gain access to the neck, a few of the patients in the robotic group encountered skin flap tip necrosis, which needed revision. This could be reduced by reducing the acute curvature of the retroauricular incision. The reasons for re-explorations in both groups were hematoma evacuation and anastomotic revision. The average days of hospitalization were about 8 in both groups. The days varied depending on postoperative recovery and healing of patients and were unrelated to the type of neck dissection done. The time taken for RAND was found to be more by an average of 2.36 hours, attributable to docking of the robot, increased time of flap elevation, and the learning curve of surgeons. Lee et al. [9] compared the feasibility of the surgical technique and cosmesis between robot-assisted supra-omohyoid neck dissection in cN0 oral cavity cancer to the conventional technique and showed a clear cosmetic benefit with longer operation time in the robot-assisted procedure. Tae et al. [13] analyzed technical feasibility and oncologic safety with early HNSCC who underwent TORS and concomitant robotic selective neck dissection via the postauricular facelift approach. The mean operative time was found to be 276±48 minutes, and the mean number of lymph nodes removed was 19.3±7.3. Greer Albergotti et al. [14] studied the operative time, estimated blood loss, lymph node retrieval, total drainage, hospital stay, and complications, reporting that operative times were longer in robot-assisted neck dissection (mean, 234 minutes) than conventional neck dissection (mean, 110 minutes). There were no significant differences between the 2 groups in terms of the other outcomes.

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We noted a steep learning curve with respect to functional preservation and duration of surgery in robotic neck dissection. In our study, case selection was prioritized by selecting 80% of patients with clinically and radiologically N0 necks. This was done to allow for the learning curve and prevent adverse effects. The comparative conventional neck arm was also selected with the same number of N0 necks to eliminate bias. Compared with studies done in other international centers, our data showed that RAND is a minimally invasive surgery that can achieve an excellent cosmetic result while maintaining comparable oncologic and functional outcomes. The additional cost of robotic surgery is justifiable for the select few patients who prefer a concealed scar.

In conclusion, our experience with RAND, we have found that it has similar oncological outcomes compared to conventional open surgery. Although the functional outcomes of RAND are comparable with open surgeries, there exists a definitive learning curve. Therefore, RAND is a feasible alternative that can be offered to individuals that would prefer a concealed scar/incision at additional cost.

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