To the Editor:
We have read with great interest the article by Hoyer-Sorensen et al. (1), showing no differences in post-operative pain after adenexal surgery performed by single-port vs. standard laparoscopy. There are currently few studies in the literature on this topic. In particular, two retrospective case-control (2, 3) and two prospective randomized trials (4, 1) evaluate pain after treatment of adnexal pathology with different surgical approaches (LESS vs. standard laparoscopy), but their results are conflicting.
Focusing on the two randomized trials, the Norwegian study (Hoyer-Sorensen et al.) is very similar to the Italian one (Fagotti et al.) in structure and patient enrollment. However, there are some differences, which could explain the opposite results: i) the number of patients (in particular, there is a larger number of patients in the Italian study than in the Norwegian one); ii) the routine occurrence of pre- and intra-operative analgesia in the Norwegian study, which was never performed in the Italian series; and iii) the timing and site of pain assessment.
If we look at the specific results, we notice that the VAS score comparison can only be performed for a period between the fourth and eighth hours, since pain was assessed at 4 and 8 hours in the Italian study and at 6 hours in the Norwegian one. In this subgroup, we notice that the median VAS score substantially overlaps for LESS surgery in the two studies. On the contrary, VAS data regarding standard laparoscopy rather differ, being much higher among Italian patients than Norwegian patients. It is conceivable that the inoculation of anesthetic in the trocar’s site can justify the lack of pain in the lower abdomen, which is typical of standard laparoscopy. On the other hand, the shoulder tip pain, which appears higher in the LESS group, is strongly related to irritation of the phrenic nerve by CO2, which may easily accumulate in this surgery due to the steep Trendelenburg position as well as the low number of exsufflation sites.
Finally, regarding cosmesis, skin closure of ancillary ports with glue may certainly influence the different results in the two studies. The psychological component of pain may be more evident and influenced by the type of surgery (number of ports) experienced. Both cultural and social factors can influence cosmesis and pain perception.
In conclusion, pain and cosmesis are difficult items to assess, although strict scientific criteria are adopted. Only large, multicentric non-inferiority trials will probably definitively solve the question.
Anna Fagotti, M.D., Ph.D.
Carolina Bottoni, M.D.
Francesco Fanfani, M.D.
Giovanni Scambia, M.D.
Catholic University of the Sacred Heart, Rome, Italy
1. Hoyer-Sorensen C, Vistad H, Ballard K. Is single-port laparoscopy for benign adnexal disease less painful than conventional laparoscopy? A single-center randomized controlled trial. Fertil Steril, In Press, DOI:10.1016/j.fertnstert.2012.06.016.
2. Yim GW, Lee M, Nam EJ, Kim S, Kim YT, Kim SW. Is single-port access laparoscopy less painful than conventional laparoscopy for adnexal surgery? a comparison of postoperative pain and surgical outcomes. Surg Innov 2012, Epub ahead of print.
3. Kim TJ, Lee YY, An JJ, Choi CH, Lee JW, Kim BG, et al. Does single-port access (SPA) laparoscopy mean reduced pain? A retrospective cohort analysis between SPA and conventional laparoscopy. Eur J Obstet Gynecol Reprod Biol. 2012 May;162:71-4.
4. Fagotti A, Bottoni C, Vizzielli G, Alletti SG, Scambia G, Marana E, et al. Postoperative pain after conventional laparoscopy and laparoendoscopic single site surgery (LESS) for benign adnexal disease: a randomized trial. Fertil steril 2011;96:255-9.
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2012.10.014
The author responds:
The rationale behind single-port laparoscopy resulting in less post-operative pain than standard laparoscopy, lies in the theory that a significant part of the pain is related to the incision made through the abdominal wall. The localization and the length of the incision(s) should thereby influence the experienced post-operative pain.
If the total length of the incisions from standard laparoscopy is added up, the difference from single-port laparoscopy could probably be neglected, especially if a specimen is removed through the umbilicus with the need for a slightly longer incision. Following this reasoning, there should be no difference in the experienced pain between these two techniques. If the number of incisions is important because different pain tracks are activated, this should theoretically result in more pain after standard laparoscopy.
The localization of the incisions could also be of importance. Could lateral incisions inflict more pain on the patient because of the penetration of the muscular layers, which is not performed through a midline incision?
So, if there is no difference in post-operative pain between the two techniques, it might be as simple as this; the experienced pain after therapeutic laparoscopy is entirely related to the surgery performed inside the abdomen regardless of the entry technique used.
Christian Hoyer-Sorensen, M.D.
Sorlandet Hospital Health Authority, Kristiansand, Norway
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2012.10.015