Optimal Viewing Direction of the Oblique Laparoscope in Single-Incision Laparoscopic Percutaneous Extraperitoneal Closure for Inguinal Hernia

Introduction

Single-incision laparoscopic percutaneous extraperitoneal closure (SILPEC) for patients with inguinal hernia is one of the most commonly performed laparoscopic surgeries in pediatric surgery in Japan. Laparoscopic percutaneous extraperitoneal closure (LPEC) was first developed by Takehara in 1995 as a new method of repairing inguinal hernia by laparoscopy with a special needle device. ¹ Because of its easy technique and benefit of visualization of contralateral patency, LPEC is now widely performed all over Japan. Uchida et al. ² in 2010 and Yamoto et al. ³ in 2011 reported SILPEC, which is LPEC performed with a single incision. The scar of SILPEC is almost invisible as assessed by the parents of patients in a questionnaire survey, ⁴ but it is more difficult to manipulate forceps during SILPEC than during LPEC. Nowadays, almost all cases of laparoscopic surgery for inguinal hernia in Japan are performed by LPEC or SILPEC, and which technique is used depends on the decision at each hospital.

In contrast, a suturing technique has usually been used to close hernia orifice in other countries; for example, a purse-string suture according to Montupet's technique and an N-shaped suture according to Schier's technique have been developed. ⁵ The merit of these methods is the lack of a need for a special device such as the device used in LPEC. Esposito et al. ⁶ reported the standardized three-port laparoscopic surgery technique that can treat neonatal inguinal ovarian hernia, one of the most difficult cases, with good results. They mentioned the importance of maintaining the position of the two working ports on the same line as the camera port to obtain a larger working space and to avoid clashing between the optic and the instruments. ⁶ Standardization of surgical technique can maximize mobility of forceps and safety of procedure in every surgery, and should be applied to our SILPEC procedure.

SILPEC is more difficult to perform than LPEC because of collisions between instruments, and this has prevented the SILPEC procedure from becoming more widely performed. The surgeon's forceps and laparoscope sometimes collide with each other and the surgeon may feel uncomfortable about moving the forceps during the procedure if the assistant who is holding the laparoscope is inexperienced. In SILPEC, the oblique laparoscope is used because it is very helpful in the small working space in pediatric endoscopic surgery, ⁷ in particular single-incision laparoscopic surgery (SILS),^8,9 but special skills and experience that are difficult to teach verbally are required to manipulate this laparoscope.

It was hypothesized that one of the reasons for the high frequency of collisions between instruments during SILPEC is wrong viewing direction of the oblique laparoscope. If the optimal viewing direction of the oblique laparoscope during SILPEC is obtained, manipulation of the oblique laparoscope can be standardized, and it would allow maximal mobility of instruments. Furthermore, it would lead to the ability to verbally teach younger surgeons how to manipulate the oblique laparoscope during SILPEC. In this study, it was analyzed how the oblique laparoscope was being manipulated during SILPEC with the field stop pointer that is a basic function of the laparoscope made by Stryker Corporation. This is the first study using the field stop pointer to assess the optimal viewing direction of the oblique laparoscope to avoid collisions between instruments during SILPEC.

Materials and Methods

This study was approved by the ethics committee of Gunma Children's Medical Center (No. GCMC2018-108). A retrospective chart review was performed on patients who underwent SILPEC at Gunma Children's Medical Center between April 2016 and April 2017.

Surgical technique

Our SILPEC procedure was performed according to the procedure described in previous reports from Saitama Children's Medical Center.^2,4 A 4 mm port for the 30° oblique laparoscope (IDEAL EYES microlaparoscope 2.9 mm 30° autoclavable, 502-290-030) is inserted with the open technique through the 1 cm vertical umbilical incision. A 3 mm inside-bended forceps is inserted through the same umbilical incision with a different entrance. The internal inguinal ring is encircled by 2-0 nonabsorbable thread that is handled by a 19-gauge needle device (Lapaherclosure™; Hakko Medical Co., Nagano, Japan), this needle device has a wire loop to hold the suture material at the tip. First, Lapaherclosure is inserted to the lateral side of the hernia orifice. The tip of the needle of the Lapaherclosure is moved through the dorsal side to the medial side of the hernia orifice while maintaining the preperitoneal space with the aid of the forceps. After puncture of the peritoneum, the thread is released from the Lapaherclosure and placed in the intraperitoneal space. The Lapaherclosure is pulled back to the first insertion point while maintaining the preperitoneal space. Second, the Lapaherclosure is pushed again through the ventral side to the same puncture point of the peritoneum. Then, the thread is grasped again by the Lapaherclosure, and the Lapaherclosure and the thread are pulled out from the body. Finally, the thread is tied extracorporeally, and the internal inguinal ring is completely closed. The forceps is used to create optimal tension on the peritoneum while the surgeon pushes the Lapaherclosure and grasps or releases the thread intracorporeally. After this procedure is completed, an asymptomatic contralateral internal inguinal ring is routinely observed, and prophylactic surgery is performed in patients with a contralateral patent processus vaginalis. The umbilical wound is closed by an absorbable suture, whereas the needle puncture wounds do not require suturing.

The viewing direction of the 30° oblique laparoscope was assessed by the field stop pointer that is a function of the laparoscope made by Stryker Corporation (Kalamazoo, MI) (Fig. 1). The field stop pointer shows the viewing direction of the oblique laparoscope on the surgical monitor, and the location and movement of the field stop pointer can be reviewed retrospectively in the surgical video. The viewing direction at the beginning and that at the end of the procedure were measured on the monitor using a protractor. Three ranges of viewing direction were defined: the inside viewing direction was from −90° to −11°, upward viewing direction was from −10° to 10°, and outside viewing direction was from 11° to 90°. The patients were divided into three groups according to the viewing direction at the beginning of the procedure.

OPEN IN VIEWER

FIG. 1.

Endoscopic view on the surgical monitor when performing SILPEC for right inguinal hernia. The field stop pointer on the monitor indicates the viewing direction of the 30° oblique laparoscope. In this case, the viewing direction was categorized as the outside viewing direction. SILPEC, single-incision laparoscopic percutaneous extraperitoneal closure.

The length of the procedure, the viewing direction at the end of the procedure, and the percentage of cases in which there was a change in category of viewing direction during the procedure were compared. Demographic data are expressed as mean ± standard deviation (SD), and analyzed using analysis of variance or Fisher's exact test. A P value <.05 was deemed as statistically significant.

Results

Ninety-eight cases of SILPEC were performed using the Stryker laparoscope during the study period. The mean viewing direction of the cases at the beginning of the procedure was 1.5 ± 31 (SD), and the mean viewing direction at the end of the procedure was 8.8 ± 31.

Table 1 gives the patient characteristics, procedure time, and viewing direction of the three groups. The percentage of patients in whom there was a change in category of viewing direction through the laparoscope in the inside, upward, and outside groups was 35%, 21%, and 11%, respectively, showing a significant difference among the three groups (P = .047).

Discussion

Our results showed that setting the initial viewing direction to the outside can reduce correction of the viewing direction during SILPEC. This suggests that fewer collisions between the laparoscope and forceps would occur when the viewing direction is set to the outside at the beginning of the procedure. Because the intersection angle between the outside-viewing laparoscope and inside-bended forceps is close to a right angle, the distance between the handle of the laparoscope and the handle of the forceps becomes wide and fewer collisions would occur. In other words, if the laparoscope is initially set to the inside direction, the laparoscope and the forceps become parallel with each other, and collisions are more likely to occur. When the laparoscope is initially set to the outside direction, the laparoscope intersects the forceps at a wide angle, and fewer collisions would occur.

In SILS, some methods of avoiding collisions between instruments have been reported. Hansen et al. ⁸ reported eight techniques to minimize instrument clashing. They stated that crossing instruments intra-abdominally moves hands away from each other. They also stated that a 45° angled endoscope is very helpful. The use of a roticulating instrument^4,8,10 or instruments of different overall lengths^8,11 has been recommended in several articles.

Knowing the optimal endoscopic viewing direction is very helpful for standardizing the technique of SILPEC and for surgical education. It can reduce trial and errors when novice endoscopists are learning the endoscopic manipulation technique in on-the-job training. Previous studies on camera assistants reported only about skill assessment and training.^12–14 Ganai et al. ¹² reported that virtual-reality training improves endoscopic skills. Huber et al. ¹³ reported a validated skill evaluation system. Ishimaru et al. ¹⁴ reported a skill evaluation system for camera assistants using an infant-sized box trainer. It might be important to combine skill training for camera assistants and teaching optimal standardized manipulation of the laparoscope to novice endoscopists.

There are some limitations in this study because of the retrospective nature of this study. Procedure time was assessed as surgical outcome in each group, but there was no significant difference among the three groups. The endoscopists who performed SILPEC in the inside group requested frequent movements to change the viewing direction; however, changing the viewing direction required only a few seconds. This might be the reason why the procedure time was not different among the three groups. In a future study, the actual incidence of collisions between instruments and comfort of the surgeon will be observed prospectively as surgical outcome.

In conclusion, setting the initial viewing direction to the outside can reduce correction of the viewing direction during SILPEC. The field stop pointer is useful for assessing manipulation of the oblique laparoscope and standardization of surgical procedures.