Pain after laparoscopic appendectomy: a comparison of transumbilical single-port and conventional laparoscopic surgery

Laparoscopic appendectomy is now considered the gold standard for appendectomy, even in complicated appendicitis [1]. The reported advantages of laparoscopic appendectomy compared with open appendectomy are less postoperative pain, less wound infection, and better cosmetic results [2, 3]. Multiple case series and comparative analyses have recently described single-port or single-incision surgery for the treatment of acute appendicitis [4-12]. The great majority of these studies have demonstrated technical feasibility and good cosmetic results. However, to date there are no reported advantages of these procedures over conventional laparoscopic appendectomy except for cosmetic results. Disadvantages of single-port or single-incision appendectomy seem to include more postoperative pain due to longer operative time and a larger fascial incision compared to conventional laparoscopic appendectomy. However, only a few studies have assessed pain after single-port or single-incision appendectomy indirectly based on analgesic dose [8, 10, 13, 14] or directly based on visual analogue scale (VAS) pain scores [10, 14]. Therefore, we conducted a prospective observational study comparing pain after transumbilical single-port laparoscopic appendectomy (SA) and conventional three-port laparoscopic appendectomy (TA) for simple appendicitis.

From April to September 2011, 50 consecutive patients underwent laparoscopic appendectomy for simple appendicitis without gangrene or perforation performed by one surgeon at our hospital. Patients who had undergone appendectomy with a drainage procedure were excluded. The type of surgery was chosen based on patient preference after written informed consent was obtained. SA was performed using a SILS port (Covidien, Norwalk, CT, USA) in 17 patients. The other 33 patients underwent TA.

SA surgical technique

The patient was placed in a supine position with the surgeon and assistant on the patient's left and right, respectively. A 20 mm longitudinal incision was made through the umbilicus and the fascia and peritoneum were opened under direct vision; therefore the natural umbilical defect was used to access the intraperitoneal cavity. The SILS port was then inserted into the incision. Three 5 mm cannulas were inserted into the SILS port at different heights to reduced clashes between the cannulas, and insufflation of carbon dioxide gas through a three-way catheter was performed to achieve pneumoperitoneum (Fig. 1).

Fig. 1
Transumbilical single-port laparoscopic appendectomy (SA). (A) Preoperative view. (B) A longitudinal umbilical incision about 20 mm in length. (C) The SILS port was inserted into the umbilical incision. (D) External view during SA. (E) The mesoappendix was first divided using ultrasonic shears. (F) The base of the appendix was ligated using a round loop. (G, H) The resected appendix was removed with the aid of a bag.

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The operation was performed with the surgeon and assistant (scopist) positioned on the left side of the patient. The patient was placed in the Trendelenburg position with the left side down. A rigid 0°5 mm laparoscope and 5 mm laparoscopic instruments were inserted through the cannulas. Appendectomy was performed in a similar manner with TA, but it was difficult to adhere to the traditional laparoscopic principles of triangulation due to instrument clashes (Fig. 1). The mesoappendix was first divided using ultrasonic shears (Harmonic Scalpel, Ethicon Endo-Surgery Inc., Cincinnati, OH, USA), and then the base of the appendix was ligated using a round loop (Laploop, Sejong Medical Co., Paju, Korea) and resected. After changing one of the 5 mm cannulas to a 5 to 12 mm cannula, the resected appendix was removed through the 5 to 12 mm cannula with the aid of a bag (Lapbag; Sejong Medical Co.). The umbilical fascia was closed with 2-0 Vicryl sutures, and the subcutaneous layer was sutured with 4-0 Vicryl to the alignment of the skin edges without skin suture.

Laparoscopic surgeons have made great efforts to improve perioperative outcomes in patients undergoing appendectomy. The establishment of three ports via the umbilicus, the suprapubic region and the left iliac fossa is currently considered the best approach to achieve proper triangulation [15]. The use of two trocars has been investigated retrospectively, but no significant advantage was found [16]. At present, there is no evidence that a single-port technique is an adequate alternative to standard laparoscopic appendectomy. A recent prospective randomized trial of single-incision versus standard three-port laparoscopic appendectomy was performed and found that operative time, doses of narcotics, surgical difficulty and hospital charges were greater with the single-site approach [13]. Several other minimally invasive single-port or single-incision techniques have been introduced for the treatment of acute appendicitis [4-13, 17]. However, the majority of these studies have demonstrated only safety, feasibility or ambiguous cosmetic outcomes, without definitive advantages over conventional laparoscopic appendectomy.

As the number of ports is reduced to one, the length of the single fascial incision tends to be longer. The length of the fascial incision is closely associated with postoperative wound pain. The single umbilical incisions reported in other studies typically reached lengths of 15 to 20 mm [4, 6-8, 10, 12, 13]. However, there are only a few studies that have assessed pain after single-port or single-incision appendectomy. One prospective study found more total doses of analgesia were given to single-site patients during their hospital stay, but not during convalescence [13]. Another prospective study reported that VAS pain score during the first 24 postoperative hours was significantly higher in patients who underwent SA [14], whereas two retrospective studies did not find differences in postoperative pain between SA and TA [8, 10]. The present prospective study focused on postoperative pain and showed that pain score in the 24 hours after surgery was higher in patients who underwent SA, and that the change in postoperative pain score over time was significantly different between the two groups. These discrepancies in findings among studies may be due to different surgical techniques, operative time, and study design. In this study, the longitudinal fascial incision made through the umbilicus to insert the SILS port had a length of 20 mm. In surgical techniques using a 15 mm single umbilical incision, there was no difference in terms of VAS pain score and postoperative analgesic requirements [8, 10]. However, these two studies were retrospective, and the primary outcome assessed was not postoperative pain [8, 10].

Our other concern was operative time. Our study found SA to have an approximately 15 minutes longer operative time, which was statistically significant. Longer operative time may translate to more stretching of the single umbilical wound, and subsequently more postoperative pain. A limitation of this investigation is that it was not a randomized double blind study. However, the postoperative pain assessment was somewhat blinded as all scoring was performed by the attending nurse who was unaware of the ongoing study.

The only advantage of SA over TA may be improved cosmetic results, although no studies have objectively evaluated the cosmetic results of SA (Fig. 4). To emphasize the cosmetic advantages of SA, an objective assessment of cosmesis should be performed comparing SA with TA in the future. However, although cosmetic results may be better in SA, cosmesis may not outweigh other perioperative disadvantages. The time to pass gas was longer in the SA group in this study, and postoperative pain may be associated with delayed passage of gas.

Fig. 4
Example of cosmetic results in this study. (A) At the time of closure. (B) Seven days postoperatively.

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Surgeons should make an effort to reduce postoperative pain in SA patients, especially in the 24 hours after the SA. In this study, patients who underwent SA tended to receive more total doses of analgesics (NSAIDs) in the 24 hours after operation, but there was no statistical difference between groups due to the small sample size and the relatively small number of analgesic doses administered in both groups. The mean number of analgesic doses administered in the 24 hours after SA was 1.2 in this study. The postoperative dose of analgesics was somewhat small in part due to a superstition in Korea in which surgical patients believe that postoperative analgesics impede wound healing. In another study, the mean number of analgesic doses during a mean of 22.7 hours in the hospital after SA was 9.6 [13].

Various modalities besides pharmacologic agents for postoperative pain control have been developed. Among them, local anesthetic infiltration and transversus abdominis plane (TAP) blocks to control postoperative port-site pain have yielded variable analgesic effects [18-20]. Further trials focused on the effects of local anesthetic infiltration or TAP blocks after SA are planned at our hospital.

In conclusion, laparoscopic surgeons should be concerned about longer operation times and higher immediate postoperative pain scores in patients who undergo SA.