Introduction

The Endoscope Manipulator Robot (EMARO) is a pneumatically driven endoscope-holder robot (Fig. 1). The surgeon wears a gyroscope on their head and uses their head movements to control the surgical field (Fig. 2, Video Clip). Hence, the surgeon can stabilize the surgical field and perform the surgery using intuitive procedures. EMARO leads to smooth surgical progression. Recently, several reports have described robotic inguinal hernia repair [1,2,3]. However, robotic inguinal hernia repair is costly, and its benefits remain unclear [2]. Despite this drawback, laparoscopic inguinal hernia repair using EMARO can only be performed by a single surgeon. Therefore, surgery using EMARO is cost-effective and it can help to solve labor shortages.

Fig. 1
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The Endoscope Manipulator Robot (EMARO)

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The present study investigated the surgical outcomes of laparoscopic inguinal hernia repair using EMARO.

Materials and methods

Patients

This retrospective study included 51 patients who underwent laparoscopic inguinal hernia repair at a single institution in the Department of Surgery, Shiroishi Kyouritsu Hospital between January 2021 and March 2024. The medical records of all the patients were reviewed in detail. Patients with unilateral and primary inguinal hernias were eligible for inclusion in this study.

In this study, the 51 patients were divided into two groups: laparoscopic surgery with and without EMARO. Patients underwent the surgeries by three surgeons. Patients who underwent treatment using EMARO were randomly selected regardless of the hernia size and surgeon. All the patients and their families were informed of the surgical procedure and provided written informed consent. The Medical Ethics Committee of Shiroishi Kyouritsu Hospital reviewed and approved the study design (permission number: 20,252).

Approach

The diagnosis of inguinal hernia was confirmed by physical examination, ultrasonography, or computed tomography (CT). Patient characteristics, intraoperative parameters, and postoperative parameters were analyzed. The following data were obtained from medical records: sex, age, hernia site, hernia type, mesh and tacker type, operation time, intraoperative bleeding, postoperative complications, postoperative analgesic, and postoperative stay. All patients underwent standard clinical outpatient follow-up with their surgeons to assess the development of seroma, surgical site infection, dysesthesia, chronic pain, and clinical recurrence.

Surgical procedure and patient management

All patients underwent laparoscopic inguinal hernia repair using a transabdominal preperitoneal approach (TAPP). The following laparoscopic instruments were used in the surgeries: laparoscopic coagulation shears (Sonicbeat, Olympus), mesh (3D Max light mesh, Bard, or Versatex monofilament mesh, Covidien), and a tacker (Bard Capsure, Bard, or Absorba Tack, Covidien). Closure of the peritoneum was performed using a 4 − 0 PDS (Ethicon). The surgeon used the same instruments during laparoscopic surgery using EMARO (E-TAPP) and conventional laparoscopic surgery (L-TAPP). TAPP was performed in the Trendelenburg position and with lateral elevation to the hernia side in both groups. Hernia repair was performed according to standard surgical principles. The mesh was used as follows: basically, 3D MAX light mesh was generally used. However, Versatex was sometimes also used for some patients, including those with small or large body type who needed mesh trimming. In addition, the tacker was used as follows: generally the Bard Capsure was used. However, the Absorba Tack was also used for patients with a small hernia gate. The tacker was used in five places (Cooper’s ligament, dorsal surface of the rectus abdominis muscle, both sides of the inferior epigastric artery and vein, and the outermost side of the mesh). The European Hernia Society Groin Hernia classification has been used for the classification of inguinal hernias [4]. Postoperative complications were defined according to the Clavien-Dindo classification (CD) [5, 6]. The length of follow-up was calculated from the time of surgery to the most recent clinical note in the patients’ medical records.

Statistical analyses

Continuous variables were expressed as medians and ranges. Statistical analyses were performed using the chi-square test, or Mann-Whitney U test, as appropriate. P values of < 0.05 were considered to indicate statistical significance. All analyses were performed using the SPSS version 25 software program (IBM Japan, Tokyo, Japan).

Results

Fifty-one patients underwent inguinal hernia repair in our department. Fifteen patients (29%) underwent E-TAPP and 36 (71%) underwent L-TAPP. There were no significant differences in the clinical characteristics between the two groups (Table 1). The surgical outcomes are shown in Table 2. The median operation times for E-TAPP and L-TAPP were 81 min (range, 77–87) min and 70 min (range, 60–94), respectively, and the median blood loss was 5 mL (range, 1–5) and 2 mL (range, 1–5). None of the groups required conversion to an anterior open approach. All E-TAPP surgeries could be completed as solo surgeries, with minimal additional time required in the preoperative setting. The setup time for EMARO was approximately 8 min (range, 5–12). E-TAPP showed a slight increase in operative time compared with L-TAPP; however, the difference was not significant. Regarding postoperative complications, one case of seroma (CD ≥ 2) was observed in the L-TAPP group. No other complications or clinical recurrence were observed in either group. The number of patients who used postoperative analgesics in the E-TAPP and L-TAPP groups was four (four patients with single use and no patient with multiple use, n = 15) and 22 (14 patients with single use and eight patients with multiple use, n = 36), respectively, with a significant difference between the two groups (p = 0.042). The type of analgesic that was administered was most commonly 60 mg of loxoprofen, however, 500 mg of acetaminophen was administered for patients with renal dysfunction. The postoperative stays in the E-TAPP and L-TAPP groups were 4 days (range, 2–6) days and 5 days (range, 3–6) days, respectively, which were not statistically significant.

Table 1 Clinical characteristics
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Table 2 Surgical outcomes
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Discussion

This retrospective study aimed to evaluate the surgical outcomes of E-TAPP. TAPP is an established, minimally invasive, and widely used approach for inguinal hernia repair. This technique was first reported by Arregui et al. in 1992 [7]. TAPP is a common surgical technique for inguinal hernia repair, and its outcomes have been extensively reported. Compared to open procedures, laparoscopic repair reduces postoperative pain and shortens convalescence [7,8,9]. Thus, TAPP provides a reliable diagnosis of inguinal hernias. This technique also allows contralateral observation and simultaneous repair.

EMARO was initially created by the Riverfield Corporation (Tokyo, Japan) in July 2015 [10]. In conventional laparoscopic surgery, the laparoscope is handled by a camera assistant according to verbal instructions from the surgeon. In contrast, in this system, the laparoscope is held by a pneumatically driven robotic arm that is controlled to follow the surgeon’s head movements (Fig. 2, Video Clip). EMARO is pneumatically driven; therefore, this robot is quiet, smooth, and highly ergonomic. The flexibility of the robot also allows it to absorb the impact of butting between the laparoscope and the forceps. Therefore, surgeons can avoid unintentional organ damage, thus leading to safe surgery. If there is an emergency during surgery, the robot can easily be stopped by hand, even if it is still in operation. Surgeons can freely set the speed of laparoscopic movement, thus ensuring intraoperative safety. A footswitch monitor allows surgeons to operate safely without moving their eyes from the surgical field (Fig. 2, Video Clip). By stepping on the footswitch, the surgeon could control the pan, tilt, zoom, and roll. In addition, the robot is linked to the surgeon’s head movement only when the foot switch is stepped on; therefore, the robot does not move at unexpected times. This system allows for flexible movement and no time lag in the head movement. Therefore, surgeons can perform surgery without stress. Interestingly, the use of postoperative analgesics was significantly lower in the E-TAPP group. EMARO has the potential to absorb the impact of interference between the forceps and the laparoscope, because this robot is pneumatically driven. Therefore, EMARO is less stressful regarding the umbilical port site and it may therefore reduce postoperative wound pain.

Fig. 2
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E-TAPP surgery scene. The surgeon wears a gyroscope (red arrow) on their head and uses their head movements to control the surgical field. The footswitch monitor (red circle) allows the surgeon to operate the device safely without removing their eyes from the surgical field

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In this retrospective study, laparoscopic inguinal hernia repair was performed using EMARO. EMARO is suitable for use in TAPP because the surgical field does not move widely. E-TAPP allows for surgery with a non-shaking field of view, and the surgical technique is the same as that used for L-TAPP. Figure 3 shows the port arrangement of the E-TAPP, position of the surgeon, and EMARO. The first 12 mm trocar was placed in the umbilicus, and two other 5 mm ports were placed bilaterally in the midclavicular line of the L-TAPP [4]. However, to prevent butting with the EMARO, surgeons place the 5 mm port slightly lateral to the contralateral side in the E-TAPP. In other words, the first trocar and the surgeon’s contralateral port were separated by approximately 10 cm. EMARO is compatible with various laparoscopes, including flexible and rigid laparoscopes. In addition, this robot is particularly compatible with 3D laparoscopes. In cases of bilateral inguinal hernias, both sides can be operated on without changing the location of the EMARO and the surgeon. EMARO is a lightweight device weighing 125 kg, which makes it easy to roll in and out during surgery. Robotic inguinal hernia repair tends to increase the operation time in comparison to laparoscopic surgery [4, 11, 12]. E-TAPP slightly increased the operation time compared with L-TAPP; however, this difference was not statistically significant. The slight time extension for the E-TAPP was mostly associated with the time for setting up the EMARO and removing the laparoscope for self-cleaning.

EMARO is relatively inexpensive and financially superior to other robots, such as the da Vinci surgical robot. The selling price of EMARO is approximately one hundred thousand dollars. In addition, E-TAPP allows for solo surgery, thus reducing labor costs in comparison to L-TAPP. There have been several reports on endoscopic holder robots that allow solo surgery [13,14,15]. The operations of these endoscopic holder robots were performed safely and were comparable to conventional operations performed by assistants [13,14,15]. Further benefits associated with the use of robotic assistance include greater stability of view, less inadvertent smearing of the lens, and a reduction in fatigue [13]. In previous reports, the feasibility of solo-assist in laparoscopic inguinal hernia repair has been demonstrated with no adverse device-related events [14, 15]. The EMARO is inexpensive and easy to use. EMARO is an effective device for low-volume centers with labor shortages. This study is associated with some limitations, including its retrospective design and the fact that it was conducted at a single institution with a relatively small study population. Therefore, further studies are necessary to increase the sample size and validate these results.

In conclusion, laparoscopic surgery using EMARO was not inferior to conventional laparoscopic surgery in terms of the surgical outcomes and it could be safely performed. As a result, laparoscopic surgery using EMARO can reduce labor costs and postoperative pain.

Fig. 3
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The port arrangement in the E-TAPP. The first 12 mm trocar and the surgeon’s contralateral 5 mm port were separated by approximately 10 cm to prevent butting during the procedures performed using EMARO. Yellow indicates the hernia site. Video Clip Control of the surgical field by head movement

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