Dual-port distal gastrectomy for the early gastric cancer

Recently, a trend in the refinement of laparoscopic procedures has been toward minimizing the number of incisions to reduce invasiveness. One such approach is SILS. SILS was described as early as 1992 by Pelosi et al. [12] who performed a laparoscopic appendectomy, and by Navarra et al. [13] who performed a laparoscopic cholecystectomy in 1997. Because SILS can be performed using refinements of existing techniques and technology, it has spread widely to many conventional laparoscopic fields, such as colectomy [14, 15], hysterectomy [16], gastrectomy [17, 18], and the urological field [19, 20].

The SILS technique does not rely on triangulation, which is one of the core principles of conventional laparoscopic surgery, allowing adequate operative exposure while maintaining an ergonomic position for the surgeon and assistant. Consequently, an inherent technical challenge that arises from the SILS technique is that of a compromised view and locomotive field [21]. A small additional port or reduced number of ports (reduced port surgery, RPS) are modifications that may overcome these problems [7, 22]. Our dual-port method provides an additional 12-mm port for the surgeon’s right hand. This port should prevent interference between camera maneuvers and other surgical instruments. A surgical nylon ligature with a straight needle also contributes to maintaining the visual field by lifting up the stomach without any additional surgical instruments. In particular, this procedure does not require any specific expensive instruments other than the SILS port. In combination with the SILS port, the additional 12-mm port and surgical nylon ligature enable the performance of dual-port surgery, even for complex operations such as LAG.

Although the benefits of SILS or RPS over conventional laparoscopic surgery have not been established, some advantages are expected. The cosmetic benefit is a clear advantage of the use of fewer ports such as in SILS or RPS (Fig. 6). Less postoperative pain may be an advantage because of the reduced number of incisions [9], although our data do not show reduced use of analgesics. The reduced invasiveness of SILS and RPS is also notable. In this study, shorter hospital stays and reduced numbers of complications were seen in the RPDG group. In addition, the trend of serum CRP values after surgery was lower for the RPDG group than the conventional LAG group (Fig. 5). CRP is a serum protein, the levels of which rise in response to acute or chronic inflammation. Acute injuries, such as trauma, infection or surgery, cause the release of interleukin-6 and other cytokines that trigger the synthesis of CRP by the liver [23]. During the acute phase response, the level of CRP rapidly increases within 2 h of the acute insult, reaching a peak after around 48 h. Recent research suggests that patients with elevated basal levels of CRP are at increased risk of diabetes, hypertension, and cardiovascular disease [24‐26]. Our cases, except for one RPLDG patient (2.23 mg/dl), had normal CRP levels pre-operatively and these values increased gradually until post-operative day 3. Interestingly, the peak level at day 3 showed a clearer difference between the groups than the levels at days 1 and 7, although a statistically significant difference was not seen (p = 0.053). The CRP value returned to low levels at post-operative day 7. These acute phase responses suggest that RPDG may be less invasive than conventional LAG. Although it is very difficult to explain why RPDG was less invasive, we have three suggestions. The first is simply “Reduced ports means reduced invasiveness”. Normally, conventional LAG requires four or five ports, occasionally with an additional small incision into the patient’s abdomen so that the total length of the wound size exceeds 5 cm. However, the wound size with our method is less than 4 cm. Although the difference in the total length of the surgical incision is small, the difference in the total area or volume of the abdominal injury is somewhat greater. Therefore, a smaller wound size may be less invasive and reduce subsequent cytokine production from injury sites in the abdominal cavity. Secondly, the positioning of the ports may be associated with a lower complication rate after surgery. Conventional LAG normally requires a few ports or small incisions in the upper abdomen. These upper abdominal injuries may induce minor respiratory problems, such as some degree of alveolar atelectasis, and consequent loss of lung volume, occurring in the same manner as in upper abdominal open surgery and leading to postoperative pain, diminished cough, hypoventilation, and an unfavorable closing volume/functional residual capacity relationship [27]. In particular, 40 % of our patients were over 75 years old; therefore, minor respiratory problems such as post-operative pneumonia or alveolar atelectasis were of concern. The final factor is the mental status after surgery. SILS and RPS are expected to have a better outcome in terms of the mental status of the patients after surgery because of less abdominal injury, including the cosmetic benefit. This patient satisfaction may contribute to early walking and easy breathing after surgery, resulting in lower complication rates and the lower serum CRP levels observed in the RPDG group.

In addition, port-related complications such as organ damage, adhesion, bleeding, wound infection, and hernias may be less frequent in SILS and RPS because of the lower number of ports. Larger studies of RCT are needed to confirm these advantages in the future.