Post-Operative Complications and Nipple Necrosis Rates Between Conventional and Robotic Nipple-Sparing Mastectomy

Postoperative complications and surgical outcomes of robotic versus conventional nipple-sparing mastectomy in breast cancer: meta-analysis

BACKGROUND

Breast cancer is the most common cancer worldwide, with remarkable advances in early diagnosis, systemic treatments, and surgical techniques. Robotic nipple-sparing mastectomy has been trialled; however, the complication rates, surgical outcomes, and oncological safety of this approach remain obscure.

METHODS

A systematic search of the literature was conducted from conception until September 2022. Studies examining complications and operative variables where robotic nipple-sparing mastectomy was compared with conventional nipple-sparing mastectomy were included. Primary study outcomes were complications (Clavien-Dindo grade III complications, skin or nipple necrosis, seroma, haematoma, infection, implant loss, and wound dehiscence) and oncological safety (recurrence and positive margins). The secondary outcomes included operative variables, length of stay, cost-effectiveness, learning curve, and aesthetic outcome.

RESULTS

A total of seven studies of overall fair quality, involving 1674 patients, were included in the systematic review and meta-analysis. Grade 3 complications were reduced in robotic nipple-sparing mastectomy without statistical significance (OR 0.60 (95 per cent c.i. 0.35 to 1.05)). Nipple necrosis was significantly reduced in robotic nipple-sparing mastectomy (OR 0.54 (95 per cent c.i. 0.30 to 0.96); P = 0.03; I2 = 15 per cent). Operating time (mean difference +58.81 min (95 per cent c.i. +28.19 to +89.44 min); P = 0.0002) and length of stay (mean difference +1.23 days (95 per cent c.i. +0.64 to +1.81 days); P < 0.0001) were significantly increased in robotic nipple-sparing mastectomy, whereas the opposite was true for blood loss (mean difference -53.18 ml (95 per cent c.i. -71.78 to -34.58 ml); P < 0.0001).

CONCLUSION

Whilst still in its infancy, robotic breast surgery may become a viable option in breast surgery. Nonetheless, the oncological safety of this approach requires robust assessment.

Robotic Versus Conventional or Endoscopic-assisted Nipple-sparing Mastectomy and Immediate Prosthesis Breast Reconstruction in the Management of Breast Cancer: A Prospectively Designed Multicenter Trial Comparing Clinical Outcomes, Medical Cost, and Patient-reported Outcomes (RCENSM-P)

OBJECTIVE

To compare the clinical and patient-reported outcomes of minimal access and conventional nipple-sparing mastectomy (C-NSM). The secondary outcomes investigated included medical costs and oncological safety.

BACKGROUND

Minimal-access NSM has been increasingly applied in the treatment of patients with breast cancer. However, prospective multicenter trials comparing robotic-assisted NSM (R-NSM) versus C-NSM or endoscopic-assisted NSM (E-NSM) are lacking.

METHODS

A prospectively designed 3-arm multicenter, nonrandomized trial (NCT04037852) was conducted from October 1, 2019 to December 31, 2021, to compare R-NSM with C-NSM or E-NSM.

RESULTS

A total of 73 R-NSM, 74 C-NSM, and 84 E-NSM procedures were enrolled. The median wound length and operation time of C-NSM was (9 cm, 175 minutes), (4 cm, and 195 minutes) in R-NSM, and (4 cm and 222 minutes) in E-NSM. Complications were comparable among the groups. Better wound healing was observed in the minimal-access NSM group. The R-NSM procedure was 4000 and 2600 United States Dollars more expensive than C-NSM and E-NSM, respectively. Wound/scar and postoperative acute pain evaluation favored the use of minimal access NSM over C-NSM. Quality of life in terms of chronic breast/chest pain, mobility, and range of motion of the upper extremity showed no significant differences. The preliminary oncologic results showed no differences among the 3 groups.

CONCLUSIONS

R-NSM or E-NSM is a safe alternative if compared with C-NSM in terms of perioperative morbidities, especially with better wound healing. The advantage of minimal access groups was higher wound-related satisfaction. Higher costs remain one of the major limiting factors in the widespread adoption of R-NSM.

A systematic review of robotic breast surgery versus open surgery

Robotic-assisted breast surgery (RABS) is controversial. We systematically reviewed the evidence about RABS, comparing it to open conventional breast surgery (CBS). Following prospective registration (osf.io/97ewt), a search was performed in January 2023, without time or language restrictions, through bibliographic databases (PubMed, Web of Science, EMBASE, Scopus, Trip database and CDSR) and grey literature. Quality was assessed in duplicate using Qualsyst criteria (score range 0.0-1.0); reviewer agreement was 98%. The 16 selected studies (total patients: 334,804) had overall high quality (mean score 0.82; range 0.68-0.91). Nine of 16 (56.3%) were cohort studies, 2/16 (12.5%) RCTs, and 5/16 (31.3%) case-control studies. Taking p < 0.05 as the significance threshold, RABS versus CBS was better in aesthetic results and patient satisfaction (10/11 studies; 90%), was surgically costly (4/4 studies; 100%), time-consuming (9/13 studies; 69%), and less painful in the first 6-24 h (2/2 studies; 100%) and without statistically significant differences in complication rates (10/12 studies; 83%) or short-term oncological outcomes (10/10 studies; 100%). Surgical time could be dramatically reduced by training surgical teams, reaching no significant differences between approaches (p = 0.120). RABS was shown to be feasible and safe. The advantages of RABS and long-term outcomes need further research.

The Full Continuum of Robotic Breast Surgery: Robotic-assisted Mastectomy, Robotic DIEP Flap, and Robotic Supermicrosurgery

In recent years, robotic surgery has rapidly expanded to improve surgical outcomes in a variety of surgical subspecialties. Although plastic surgery has taken longer to integrate robotic surgery into practice, the advantages of robotic-assisted surgery, including improved visualization and resolution, minimally invasive approaches, and the ability to surpass human precision and scale, have driven its more recent adoption into plastic surgery. Currently, procedures performed with robotic assistance that are considered part of the continuum of surgical treatment of breast cancer include robotic-assisted nipple-sparing mastectomy, reconstruction with the robotic latissimus dorsi flap or the deep inferior epigastric artery perforator flap, and robotic microsurgery for the flap anastomosis and/or the surgical treatment of lymphedema. The authors provide an overview of robotic surgery and how it has been integrated into the field of plastic surgery, as well as a review of the most common procedures within the field where robotic assistance can be incorporated: nipple-sparing mastectomy, robotic latissimus flap, robotic deep inferior epigastric artery perforator flap breast reconstruction, and microvascular anastomoses.

Controversies and strengths of robot-assisted mastectomy

Nipple-sparing mastectomy (NSM) is used to improve cosmetic outcomes while maintaining oncological safety in patients with early breast cancer; however, NSM requires a higher level of skill and workload than mastectomy and is associated with long, visible scars. Robotic surgical systems reduce surgeon workload and facilitate precise surgery. Considering the increasing support of robot-assisted NSM (RNSM), this paper aims to discuss the current controversies based on the research findings reported thus far. There are four concerns regarding RNSM; increased cost, oncological outcomes, the level of experience and skill, and standardization. It should be noted that RNSM is not a surgery performed on all patients but rather a procedure performed on selected patients who meet specific indications. A large-scale randomized clinical trial comparing robotic and conventional NSM has recently begun in Korea; therefore, it is necessary to wait for these results for more insight into oncological outcomes. Although the level of experience and skill required for robotic mastectomy may not be easily achieved by all surgeons, the learning curve for RNSM appears manageable and can be overcome with appropriate training and practice. Training programs and standardization efforts will help improve the overall quality of RNSM. There are some advantages to RNSM. The robotic system provides improved precision and accuracy, helping remove breast tissue more effectively. RNSM has advantages such as smaller scars, less blood loss, and a lower rate of surgical complications. Patients who undergo RNSM report better quality of life.

Mastectomy with Reconstruction Including Robotic Endoscopic Surgery (MARRES): a prospective cohort study of the Korea Robot-Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) and Korean Breast Cancer Study Group (KBCSG)

BACKGROUND

Robotic nipple-sparing mastectomy (RNSM) has emerged as a new treatment option for breast cancer and risk-reducing mastectomy (RRM) for women who have a high risk of pathogenic variants. Even though several studies have reported that RNSM is a feasible procedure, some argue that it should only be performed by specialized surgeons, and data on oncologic outcomes and patient-reported outcomes (PROs) are limited. Recently, the United States Food and Drug Administration and several surgeons warned that robotic breast surgery should be performed only by specialized surgeons and recommended that the benefits, risks, and alternatives of all available treatment options be discussed with patients so they can make informed treatment decisions. The Korea Robot-Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) has been established to evaluate, standardize, and teach this state-of-the-art procedure. We have designed a multicenter prospective cohort study entitled Mastectomy with Reconstruction Including Robot Endoscopic Surgery (MARRES) to report surgical, PRO, and oncologic outcomes.

METHODS

MARRES is a multi-institution cohort study prospectively collecting data from patients undergoing mastectomy and reconstruction. The patient inclusion criteria are adult women older than 19 with breast cancer or a high risk of breast cancer (patients with BRCA1/2, TP53, PALB2 mutations, etc.), who have scheduled therapeutic or RRM and want immediate reconstruction. Surgical outcomes, including pre- and postoperative photos, oncologic outcomes, cost-effectiveness, and PRO, are collected. The primary endpoints are postoperative complication rates within 30 postoperative days and the Clavien-Dindo grade of postoperative complications within 180 postoperative days. The secondary endpoints are 5-year postoperative recurrence-free survival and cancer incidence rate (for those who underwent RRM), patient satisfaction with reconstruction expectations preoperative (baseline) and results within 6 to 12 postoperative months, surgeon satisfaction with postoperative results in 6 postoperative months, and cost-effectiveness of the definitive surgery. Patient recruitment will be completed in April 2025, and the target number of enrolled patients is 2000.

DISCUSSION

This study will provide evidence about the surgical outcomes, oncologic outcomes, and patient satisfaction with RNSM and endoscopic nipple-sparing mastectomy (NSM), compared with conventional NSM.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04585074. Registered April 8, 2020.

Robot-assisted Nipple Sparing Mastectomy: Recent Advancements and Ongoing Controversies

Purpose of review

The purpose of this review is to summarize the recent technical advancements in RNSM, describe the ongoing teaching programs, and discuss the ongoing controversies.

Recent findings

Robot-assisted nipple sparing mastectomy (RNSM) is the newest addition to the armamentarium of surgical techniques for patients who require a mastectomy. The potential benefits of using the da Vinci® Robotic Surgical System (Intuitive Surgical, Sunnyvale, CA) are the small 3D camera and lighting offering superior visualization, the Endowrist robotic instruments offering greater range of motion, and surgeon being at a seated position at the console rendering a more ergonomic operating position.

Summary

RNSM can potentially help overcome the technical difficulties of performing a conventional NSM. Further studies are needed to elucidate the oncologic safety and cost-effectiveness of RNSM.

Modern Innovations in Breast Surgery: Robotic Breast Surgery and Robotic Breast Reconstruction

Robotic surgery has a history of applications in multiple surgical areas and has been applied in plastic surgery over the past decade. Robotic surgery allows for minimal access incisions and decreased donor site morbidity in breast extirpative surgery, breast reconstruction, and lymphedema surgery. Although a learning curve exists for the use of this technology, it can be safely applied with careful preoperative planning. Robotic nipple-sparing mastectomy may be combined with either robotic alloplastic or robotic autologous reconstruction in the appropriate patient.

Early experience of robotic axillary lymph node dissection in patients with node-positive breast cancer

BACKGROUND

Robotic surgical systems enable surgeons to perform precise movement in the surgical field using high-resolution 3D vision and flexible robotic instruments. We aimed to evaluate the feasibility and safety of performing axillary lymph node dissection using a robotic surgical system in patients with node-positive breast cancer.

METHODS

Thirty-two women with breast cancer who underwent robot-assisted nipple-sparing mastectomy (RNSM) and level I/II axillary lymph node dissection were analyzed. Patients were divided into two groups: RNSM with conventional axillary lymph node dissection (CALND) vs. RNSM with robotic axillary lymph node dissection (RALND). Clinicopathological features and surgical outcomes were analyzed.

RESULTS

The median age of the patients was 44 (range 20-59) years. Eleven patients underwent RALND. None of the clinicopathologic features differed between the two groups. There were no statistically significant differences in surgical outcomes, except for the final incision size, between the two groups. The proportion of cases with an incision ≤ 40 mm was 63.6% in the RALND group and 36.4% in the CALND group (p = 0.020).

CONCLUSION

RALND can be safely performed in RNSM. RNSM with RALND is comparable to RNSM with CALND in terms of early surgical outcomes. The incision size can be reduced when using RALND.

A Preliminary Experience of Endoscopic Total Mastectomy With Immediate Free Abdominal-Based Perforator Flap Reconstruction Using Minimal Incisions, and Literature Review

PURPOSE

Endoscopic total mastectomy (ETM) is predominantly performed with reconstruction using prostheses, lipofilling, omental flaps, latissimus dorsi flaps, or a combination of these techniques. Common approaches include minimal incisions, e.g., periareolar, inframammary, axillary, or mid-axillary line, which limit the technical ability to perform autologous flap insets and microvascular anastomoses, as such the ETM with free abdominal-based perforator flap reconstruction has not been robustly explored.

METHODS

We studied female patients with breast cancer who underwent ETM and abdominal-based flap reconstruction. Clinical-radiological-pathological characteristics, surgery, complications, recurrence rates, and aesthetic outcomes were reviewed.

RESULTS

Twelve patients underwent ETM with abdominal-based flap reconstruction. The mean age was 53.4 years (range 36-65). Of the patients, 33.3% were surgically treated for stage I, 58.4% for stage II, and 8.3% for stage III cancer. Mean tumor size was 35.4 mm (range 1-67). Mean specimen weight was 458.75 g (range 242-800). Of the patients, 92.3% successfully received endoscopic nipple-sparing mastectomy and 7.7% underwent intraoperative conversion to skin-sparing mastectomy after carcinoma was reported on frozen section of the nipple base. Mean operative time for ETM was 139 minutes (92-198), and the average ischemic time was 37.3 minutes (range 22-50). Fifty percent of patients underwent deep inferior epigastric perforator, 33.4% underwent MS-2 transverse rectus abdominis musculocutaneous (TRAM), 8.3% underwent MS-1 TRAM, and 8.3% underwent pedicled TRAM flap reconstruction. No cases required re-exploration, no flap failure occurred, margins were clear, and no skin or nipple-areolar complex ischemia/necrosis developed. In the aesthetic outcome evaluation, 16.7% were excellent, 75% good, 8.3% fair, and none were unsatisfactory. No recurrences were observed.

CONCLUSION

ETM through a minimal-access inferior mammary or mid-axillary line approach, followed by immediate pedicled TRAM or free abdominal-based perforator flap reconstruction, can be a safe means of achieving an "aesthetically scarless" mastectomy and reconstruction through minimal incisions.

Outcomes of robotic nipple-sparing mastectomy versus conventional nipple-sparing mastectomy in women with breast cancer: a systematic review and meta-analysis

The promising results of the robotic approach for multiple cancer operations has led to interest in the potential of robotic nipple-sparing mastectomy (R-NSM); however, further studies are required to compare the benefits and complications of this approach with those of conventional open nipple-sparing mastectomy (C-NSM). We performed a meta-analysis to compare surgical complications of R-NSM versus C-NSM. We performed a review of literature through June 2022 in PubMed, Scopus, and EMBASE. We included randomized controlled trials (RCTs), cohorts, case-control studies, and case series with > 50 patients comparing the two techniques. Separate meta-analyses were conducted according to study design. From 80 publications, we identified six studies. The sample size ranged from 63 to 311 mastectomies from 63 to 275 patients. The tumor size and disease stage were similar between groups. The positive margin rate was 0-4.6% in the R-NSM arm and 0-2.9% in the C-NSM arm. Four studies reported early recurrence data, which were similar between groups (R-NSM: 0%, C-NSM: 0-8%). The R-NSM group had a lower rate of overall complications compared to the C-NSM group in cohorts/RCTs (RR = 0.68, 95%CI 0.49-0.96). In case-control studies, rate of necrosis was lower with R-NSM. Operative time was significantly longer in the R-NSM group in cohort/RCTs. In early experience with R-NSM, R-NSM had a lower overall complication rate compared to C-NSM in cohorts/RCTs. While these data are promising, our results show variability and heterogeneity limiting definitive conclusions. Additional trials are needed to guide the role of R-NSM and its oncologic outcomes.

Radio Electric Asymmetric Conveyer Tissue Reparative Treatment on Post-surgical Breast Skin Necrosis. A Report of Four Cases

Breast surgical treatments for both tumors and aesthetic reasons are very frequent. The nipple-areola complex (NAC) ischemia is a possible complication after breast surgery. This lesion can be devastating for the patient in the post-surgical course and can lead to final epidermolysis. The necrosis is generally attributed to vascular compromise or excessive tension of the flaps. Actually, the phenomena that prevent spontaneous repair are due to variations in the endogenous electrical potential at the cellular level. In damaged tissues, the electric potential difference across the epithelium is often profoundly altered.

In this manuscript, we are presenting four cases of NAC necrosis that were successfully treated with reparative tissue optimization (TO-RPR) treatment of the Radio Electric Asymmetric Conveyer (REAC) technology.

REAC technology was conceived to overcome the limits of exogenous electrical stimulations. Instead of administering an electrical stimulus that imposes itself on the endogenous bioelectric activity (EBA), the REAC technology restores the correct potential difference inside the tissues, which is essential for all reparative and regenerative processes. The REAC treatment applied was able to promote a fast-healing process of the necrosis of the NAC following surgery of the breast.

Analysis of robot-assisted nipple-sparing mastectomy using the da Vinci SP system

BACKGROUND

As patients tend to be diagnosed with breast cancer at an early stage, the demand for better cosmetic outcomes has increased. Several studies revealed that robot-assisted nipple-sparing mastectomy (RNSM) shows favorable outcomes. The aim of the study was to reveal the feasibility of RNSM using the da Vinci single-port (SP) system with a minimal incision, hidden in the arm.

METHODS

From 2018 to 2021, 81 cases (70 patients) were retrospectively reviewed. Clinicopathologic characteristics, operative outcomes, and postoperative complications were evaluated. The operative outcomes were analyzed using the Mann-Whitney U test.

RESULTS

The median age was 42 years (range, 26-60 years). Bilateral RNSM was performed in 11 (27.2%) patients. The median size of the initial skin incision was 40 mm (range, 20-55 mm). Immediate reconstruction with direct-to-implant was performed in 54 (66.7%) patients and deep inferior epigastric perforator (DIEP) flaps in 15 (18.5%) patients. Postoperative complications of Clavien-Dindo Classification III occurred in six (7.5%) patients. Patients reconstructed with a DIEP flap had large breasts with more severe ptosis, yet grade III complications did not occur.

CONCLUSIONS

RNSM using the SP system can be applied for curative and risk-reducing mastectomy, regardless of breast size or ptosis grade.

Impact of Body Composition on Postoperative Outcomes in Patients Undergoing Robotic Nipple-Sparing Mastectomy with Immediate Breast Reconstruction

Nipple-areolar complex (NAC)-related complications are common during nipple-sparing mastectomy (NSM), with obesity as a risk factor. Although the incidence of NAC-related complications after robotic NSM (RNSM) with immediate breast reconstruction (IBR) is lower than that after conventional NSM, it remains one of the most unwanted complications. We aimed to evaluate body composition-based risk factors for NAC-related complications after RNSM with IBR. Data of 92 patients with breast cancer who underwent RNSM with IBR using direct-to-implant or tissue expander from November 2017 to September 2020 were analyzed retrospectively. Risk factors for NAC-related complications were identified with a focus on body composition using preoperative transverse computed tomography at the third lumbar vertebra level. Postoperative complications were assessed for 6 months. The most common complication was NAC ischemia, occurring in 15 patients (16%). Multivariate analysis revealed a low skeletal muscle index/total adipose tissue index (SMI/TATI) ratio as an independent NAC ischemia risk factor. An increase in the SMI/TATI ratio by one decreased the incidence of NAC ischemia by 0.940-fold (p = 0.030). A low SMI/TATI ratio is a risk factor for postoperative NAC ischemia in patients undergoing RNSM with IBR for breast cancer. Preoperative body composition-focused evaluation is more valuable than simple body mass index assessment.

Prospective pilot study protocol evaluating the safety and feasibility of robot-assisted nipple-sparing mastectomy (RNSM)

INTRODUCTION

Nipple-sparing mastectomy (NSM) can be performed for the treatment of breast cancer and risk reduction, but total mammary glandular excision in NSM can be technically challenging. Minimally invasive robot-assisted NSM (RNSM) has the potential to improve the ergonomic challenges of open NSM. Recent studies in RNSM demonstrate the feasibility and safety of the procedure, but this technique is still novel in the USA.

METHODS AND ANALYSIS

This is a single-arm prospective pilot study to determine the safety, efficacy and potential risks of RNSM. Up to 12 RNSM will be performed to assess the safety and feasibility of the procedure. Routine follow-up visits and study assessments will occur at 14 days, 30 days, 6 weeks, 6 months and 12 months. The primary outcome is to assess the feasibility of removing the breast gland en bloc using the RNSM technique. To assess safety, postoperative complication information will be collected. Secondary outcomes include defining benefits and challenges of RNSM for both surgeons and patients using surveys, as well as defining the breast and nipple-areolar complex sensation recovery following RNSM. Mainly, descriptive analysis will be used to report the findings.

ETHICS AND DISSEMINATION

The RNSM protocol was reviewed and approved by the US Food and Drug Administration using the Investigational Device Exemption mechanism (reference number G200096). In addition, the protocol was registered with ClinicalTrials.gov (NCT04537312) and approved by The Ohio State University Institutional Review Board, reference number 2020C0094 (18 August 2020). The results of this study will be distributed through peer-reviewed journals and presented at surgical conferences.

TRIAL REGISTRATION NUMBER

NCT04537312.

Three Cases of Bilateral Breast Absence Associated with Familial Congenital Ectodermal Defects

Objective

This study aims to analyze three cases of bilateral breast absence associated with congenital ectodermal defects in the same family to identify a suitable clinical treatment plan.

Methods

Three patients (case 1 and case 2 are a brother–sister relationship; case 3 is their father) complained of the absence of breasts, nipples, and areolas, accompanied by deformity of facial features and fingers; all other clinical indexes were normal. Case 1 first underwent bilateral papillary reconstruction, with areola embroidery carried out six months later. Case 2 first underwent prosthetic breast augmentation, and after ten months, she underwent nipple reconstruction and auricular cartilage, silica gel prosthesis rhinoplasty, epicanthus correction, and areola embroidery. Gene tests were carried out for both cases. Case 3 did not undergo any surgical procedures.

Results

The operations achieved good results, although in case 2, the reconstructed nipples retracted and became smaller. Neither of the subjects had adverse reactions after the procedures. A heterozygous mutation of the KCTD1 gene c.2020A>T (p.i674f), a mutation inherited from case 3 (their father), was detected through gene analysis. Copy number analysis and single-nucleotide polymorphism (SNP) analysis were carried out, but no copy number variation possibly related to clinical manifestations was detected.

Conclusion

The bilateral breast absence associated with familial congenital ectodermal defects in cases 1 and 2 were found to be induced by a heterozygous mutation of the KCTD1 gene c.2020A>T (p.i674f) inherited from case 3 (their father). Two of the three cases underwent surgical treatment, and good clinical results were achieved.

Postoperative pain assessment of robotic nipple-sparing mastectomy with immediate prepectoral prosthesis breast reconstruction: a comparison with conventional nipple-sparing mastectomy

Aims: Nipple-sparing mastectomy (NSM) is a surgical procedure for patients with breast cancer without nipple-areolar complex (NAC) involvement. Robotic NSM (RNSM) with immediate breast reconstruction has been recently introduced; however, reports regarding RNSM are still lacking. Therefore, this study aimed to evaluate the postoperative assessment with a focus on postoperative pain of RNSM with prepectoral immediate prosthesis breast reconstruction (IPBR) compared with conventional NSM (CNSM) in patients with breast cancer without NAC invasion. Methods: This retrospective study included 81 patients who underwent RNSM (n = 40) or CNSM (n = 41) with prepectoral IPBR using direct-to-implant or tissue expander between January 2018 and June 2020. The primary endpoint was to compare postoperative pain intensity based on a numerical rating scale (NRS). The secondary endpoint was to evaluate the postoperative recovery profile, including postoperative nausea/vomiting (PONV) and complications. Results: A statistical difference was observed in the resting NRS scores at 0-6 postoperative hours between the RNSM and CNSM groups (3.2 ± 1.5 versus 4.2 ± 1.6, respectively; Bonferroni corrected P = 0.005), however, no difference was shown at other time periods. Also, no between-group difference was found in the NRS scores for acting pain within 48 postoperative hours and the number of patients requiring additional analgesics. Conclusions: Despite a statistical difference in the resting NRS scores during the early postoperative phase, the absence of any significant difference in the requirement of additional analgesics between the groups suggested that RNSM does not significantly attenuate postoperative pain intensity.