The Effect of Postoperative Modified Trendelenburg Position to Decrease Shoulder Pain after Laparoscopic Hysterectomy: A Randomized Controlled Trial.

Laparoscopic surgery is a frequently performed technique for both noncancerous and cancerous gynecological problems. In comparison to laparotomy, this method has benefits such as less anesthetic use, accelerated recovery, and shorter durations of hospitalization. A study at a tertiary care center found that total laparoscopic hysterectomy (TLH) allows safe discharge within 24 h for patients meeting specific criteria, including effective pain control, minimal intraoperative blood loss, uncomplicated surgery, and the absence of postoperative complications. This approach does not increase the risk of readmission or delayed complications.[ 1 ] Pain is a common challenge associated with minimally invasive surgery, although it is generally less severe compared to laparotomy. In laparoscopic procedures, postoperative shoulder pain is a frequent concern, whereas hysteroscopic procedures are often associated with intraoperative pain, which can occasionally be severe enough to result in procedural failure.[ 2 ] Referred shoulder discomfort, a common issue associated with laparoscopic surgery, arises from CO2’s stimulation of the phrenic nerve. The occurrence of shoulder discomfort after surgery varies from 35% to 80%, especially during the first 24 h after the procedure.[ 3 ] This shoulder discomfort may last for a maximum of 3 days, and patients describe it as more intense than the pain immediately linked to the surgical operation. The heightened perception of pain might result in greater use of analgesic medications and has consequences for patient recovery, potentially prolonging hospitalization and, in exceptional circumstances, requiring readmission.[ 4 ] The precise processes for postoperative shoulder discomfort are still not fully understood. Experts have proposed various reasons for the phrenic nerve irritation that leads to shoulder discomfort after surgery. The following are suggested causes for this condition: carbonic acid formation, microvascular peritoneal hemorrhages, dehydration and injury to the peritoneum, tension on the visceral ligaments, and temporary nerve dysfunction. Nevertheless, none of these hypotheses can exclusively explain this phenomenon. As a result, it is hypothesized that postoperative shoulder pain is caused by a variety of factors.[ 3 5 6 7 8 9 ] Various intraoperative strategies have been developed to reduce pneumoperitoneum and consequent shoulder pain after surgery. These include pulmonary recruitment maneuvers, actively aspirating gas from the abdomen, inserting a drain inside the abdominal cavity, administering local anesthesia below the diaphragm or directly into the peritoneal cavity, and using warmed and humidified CO2. The Trendelenburg posture, another potentially advantageous approach, reduces the mechanical pressure that CO2 exerts on the diaphragm and upper abdominal muscles, thereby alleviating patient pain. The high solubility of CO2 enables it to easily move into the pelvic area, which has an extensive network of blood vessels. This promotes the absorption of pneumoperitoneum. Although these therapies have potential benefits, current studies have notable drawbacks, such as a substantial risk of bias, lack of accuracy, and variability in the results.[ 4 ] Furthermore, the existing research lacks sufficient investigation into the particular impact of the Trendelenburg posture in reducing postoperative shoulder discomfort. Therefore, the main aim of this research is to examine the influence of a modified Trendelenburg position on the occurrence of shoulder discomfort in patients at 6 h after undergoing a TLH. Furthermore, with shoulder pain, laparoscopic surgery often results in postoperative abdominal pain and frequently induces nausea and vomiting. The secondary goals of this study are to measure pain scores in the upper and lower abdomen regions, determine the intensity of nausea and vomiting, and quantify the use of analgesic and antiemetic drugs after surgery.

The research originally included a total of 94 patients. However, 48 of these individuals were later eliminated due to reasons specified in Figure 1 . Out of the total number of patients, 46 were assigned randomly to either the intervention group or the control group, with each group consisting of 23 individuals. One patient in the intervention group was omitted because they could not tolerate the modified Trendelenburg posture. Likewise, in the control group, one patient was omitted due to the cancellation of the procedure. As a result, the final data analysis consisted of 44 patients, with an equal distribution of 22 individuals in each group. Table 1 displays the fundamental characteristics of the individuals included in the research. The parameters include age, BMI, prior surgical history, menstruation status, diagnosis, type of operation, surgery duration, estimated blood loss, total CO2 use, ASA classification, and length of hospital stay after surgery. The comparison across groups demonstrates that these baseline features are statistically equivalent. Baseline characteristics BMI: Body mass index, EIN: Endometrial intra-epithelial neoplasia, CIN: Cervical intra-epithelial neoplasia, TLH: Total laparoscopic hysterectomy, SO: Salpingo-oophorectomy, EBL: Estimated blood loss, ASA: American Society of Anesthesiologist, SD: Standard deviation Table 2 presents the postoperative pain scores, which include evaluations for pain in the shoulder, upper abdomen, and lower abdomen using the NRS. The assessments were conducted systematically at 0, 6, 12, and 24 h after the procedure. The study revealed that there were no statistically significant disparities in shoulder pain levels between the two groups ( P = 0.363). However, it is worth noting that there was a tendency toward lower maximum values in the intervention group. In addition, the findings indicated that there were no notable differences between the groups in terms of upper abdominal pain ( P = 0.145) and lower abdominal pain ratings ( P = 0.050). However, it was noted that the intervention group had a considerably higher level of lower abdomen pain at 0 h compared to the control group ( P < 0.001). This might perhaps explain the reason for the intervention group’s elevated incidence of lower abdominal surgery. Postoperative pain scores NRS: Numeric Rating Scale Table 3 presents the scores for nausea and vomiting, assessed at different time points after surgery (0, 6, 12, and 24 h). The study showed that there were no significant differences in the occurrence of nausea and vomiting between the two groups at any of the evaluated time intervals. The P values for these comparisons were 0.599, 1.000, 0.307, and 1.000, respectively. Nausea and vomiting score Table 4 presents the comparative statistics about the administration of pain-relieving and anti-nausea drugs in both the control and modified Trendelenburg groups. There were no statistically significant disparities in the use of these medications across the groups, according to the study. The total quantity of analgesic and antiemetic medications

To summarize, the results of this research show that using a modified Trendelenburg posture for 6 h after surgery did not significantly reduce shoulder discomfort after TLH. In addition, the research failed to identify any notable disparities in the ratings for upper and lower abdominal pain, nausea, and vomiting or in the total use of analgesic and antiemetic drugs among the patients. This suggests that while the modified Trendelenburg position may offer some degree of comfort, its efficacy in significantly reducing postoperative discomfort in these specific areas is limited. Conception and design of the study: K.T. Data collection: B.S. Data analysis: K.T. and B.S. Manuscript preparation: K.T. and B.S. Manuscript revision: K.T. Final approved manuscript: K.T. and B.S. All authors have read and agreed to the final version of the manuscript. The data that support the findings of this study are available from the corresponding author, upon reasonable request. There are no conflicts of interest.

Efficient treatment of pain after surgery is essential for maximizing the healing process. Inadequate management of pain after surgery is associated with worse quality of life, prolonged recovery times, and an elevated dependence on opioids. These variables all lead to increased healthcare costs.[ 11 ] The etiology of postlaparoscopic shoulder discomfort remains unknown; however, it is believed to be complicated with several hypotheses presented to explain its occurrence. The first hypothesis is that the transformation of CO2 gas into carbonic acid, accelerated by carbonic anhydrase on the moist surfaces of the peritoneum and diaphragm, causes a decrease in peritoneal pH. This, in turn, harms and irritates neurons in these tissues, leading to shoulder pain. Another hypothesis is that residual gas pockets inside the abdominal cavity create pressure on abdominal structures, leading to pain. Finally, the tissue trauma or neuropraxia theory attributes the pain to the mechanical effects of pneumoperitoneum, such as the stretching or injury of the peritoneum and diaphragm, which leads to tearing of blood vessels, traction on nerves like the phrenic nerve, and the release of inflammatory mediators, thereby eliciting referred pain to the shoulder. These hypotheses emphasize the complex interaction of biochemical, mechanical, and inflammatory components that contribute to postlaparoscopic shoulder discomfort, highlighting the complicated nature of its underlying causes.[ 3 12 ] Although several treatments have been developed to decrease postoperative pain, there is still a significant occurrence of discomfort after gynecological laparoscopic surgeries. Among the effective approaches, specific techniques for releasing pneumoperitoneum, such as pulmonary recruitment maneuvers and active gas evacuation, have been shown to reduce pain intensity and the requirement for analgesics. The instillation of intraperitoneal fluids and the administration of local anesthetics into the peritoneal cavity (excluding the subdiaphragmatic area) have demonstrated moderate effectiveness in alleviating shoulder tip pain and decreasing the need for postoperative pain medication. Additionally, intraperitoneal drains may contribute to lowering pain severity and analgesic consumption within the first 48 h postsurgery. In contrast, subdiaphragmatic local anesthetics and the use of warmed or humidified CO2 have shown minimal impact on reducing shoulder tip pain, while gasless laparoscopy may paradoxically exacerbate pain severity. Although adverse events were rarely documented, these findings suggest that employing a combination of these methods may optimize pain management and facilitate postoperative recovery outcomes.[ 3 13 ] Although many treatments have shown effectiveness in controlling pain after laparoscopy, there is a lack of research specifically examining the effectiveness of the Trendelenburg posture in reducing pain after these operations. The Trendelenburg posture has been proposed to relieve discomfort by reducing the mechanical pressure exerted by CO2 on the diaphragm and upper abdominal muscles. The high solubility of CO2 gas allows it to easily move into the pelvic region, which has an extensive network of blood vessels. This could potentially accelerate pneumoperitoneum absorption. This mechanism proposes that the strategic placement of patients after surgery may impact the spread and removal of remaining CO2, thereby contributing to pain relief.[ 10 ] Limited studies have emphasized the possible use of the Trendelenburg posture in reducing postoperative shoulder discomfort. Aydemir et al . performed a prospective investigation to evaluate how the interval exaggerated lithotomy position affected shoulder discomfort in patients who were having laparoscopic cholecystectomy. Their research uncovered that this posture not only offered prompt and efficient alleviation from shoulder discomfort but also reduced the need for supplementary painkillers and opioids. Moreover, it was shown that the posture had a positive impact on enhancing respiratory function.[ 14 ] Zeeni et al . examined the advantages of maintaining the Trendelenburg posture for a duration of 24 h after gynecological laparoscopic surgeries. Researchers noted a reduction in shoulder discomfort after surgery in individuals placed in this posture.[ 10 ] Furthermore, Ahmed et al . conducted comparative research to assess the efficacy of the 24-hour Trendelenburg posture, deep breathing exercises, and the use of warm water in reducing shoulder discomfort and promoting recovery after gynecologic laparoscopy. Their study showed that all three treatments effectively decreased postlaparoscopic shoulder discomfort. The Trendelenburg posture was shown to be more effective than the other two therapies.[ 15 ] Differing from previous research methodologies, this study integrates a modified Trendelenburg position, aiming to balance between the efficacy of CO2 displacement in alleviating postoperative discomfort and the necessity of minimizing patient distress. This modified approach constitutes a less severe version of the traditional Trendelenburg posture, with patients being retained in this adjusted position for 6 h following surgery. The study’s scope was specifically narrowed to include participants who underwent TLH. Contrary to expectations, maintaining patients in the modified Trendelenburg position for 6 h postoperatively did not result in a statistically meaningful decrease in postoperative shoulder pain. However, there was a statistically insignificant tendency for the intervention group to have lower maximum shoulder pain levels compared to the control group. Furthermore, there was no statistically significant difference detected in the ratings for upper and lower abdominal pain, nausea and vomiting, or the overall intake of analgesic and antiemetic drugs. In the present study, the observed incidence of shoulder pain postsurgery was notably low. This outcome can be attributed primarily to two procedural practices. First, during the vaginal removal of the uterus, a substantial amount of the CO2 gas used during laparoscopy is released from the abdominal cavity. This reduces the volume of residual gas postsurgery, which is a known factor contributing to shoulder pain. Second, our surgical protocol includes routine manual abdominal pressure at the end of the procedure, with laparoscopic ports left open to expel residual CO2. This aligns with the standard method described in the Cochrane review, which highlights manual compression of the abdomen as an effective strategy for reducing residual pneumoperitoneum and subsequent shoulder pain.[ 3 13 ] This practice likely minimized the incidence of shoulder pain in both groups, potentially masking the specific effect of the Trendelenburg posture. Nevertheless, there are limitations. Initially, the occurrence rate of postoperative shoulder discomfort among the participants in the research was minimal, which could affect the capacity to identify notable differences between the groups that received different treatments and the group that did not. Furthermore, the intervention period was relatively short, potentially restricting the observation of the long-term effects of the modified Trendelenburg position on postoperative recovery and pain. Finally, the study lacks data on postoperative lung recruitment, a factor that could have implications for respiratory function and overall recovery.

This research was conducted at a highly specialized hospital in Thailand from May 2022 to July 2023. It followed a prospective and randomized design. The research was conducted in accordance with the Declaration of Helsinki and obtained permission from the Rajavithi Hospital Ethics Committee (IRB number 65055) and was filed on ClinicalTrials.gov ( NCT05428982 ). The CONSORT diagram [ Figure 1 ] illustrates the flow of individuals throughout the research. CONSORT diagram The research sample consisted of individuals aged 30–65 years with an American Society of Anesthesiologists (ASA) physical status of I or II. The ASA Physical Status Classification System defines ASA I as a patient in perfect health without any systemic illness. A patient with ASA II is defined as having an insignificant systemic illness that does not result in major functional impairments. These patients were scheduled to undergo TLH for noncancerous gynecologic problems. Procedures expected to last <3 h and necessitated precise 5-mm abdominal incisions were considered eligible. All participants demonstrated a high level of proficiency in the Thai language and freely gave their informed consent. Exclusion criteria for the study were as follows: pregnancy; necessity for conversion from laparoscopy to laparotomy; intra-abdominal drain insertion; surgery duration exceeding 3 h; diagnosis of gynecologic malignancy; history of chronic shoulder pain; previous shoulder surgery; conditions such as gastroesophageal reflux, gastritis, or dyspepsia; cardiovascular or pulmonary disease; venous thromboembolism; morbid obesity (body mass index [BMI] exceeding 40 kg/m 2 ); increased intracranial or intraocular pressure; liver or kidney disease; allergy to nonsteroidal anti-inflammatory drugs, paracetamol, or opioids; ongoing corticosteroid therapy; chronic use of analgesic drugs; psychiatric disorders; or a planned hospitalization of <24 h. The research randomly assigned participants in a 1:1 ratio to either the endometriosis or nonendometriosis groups. The randomization technique was stratified by blocks of four and conducted using a computer-generated method. As a result, patients were divided into two separate groups. The individuals in the intervention group were placed in a modified Trendelenburg posture, whereas those who were in the control group were positioned in a supine position. In order to maintain allocation concealment, the study used the Sequentially Numbered, Opaque, Sealed Envelopes approach. We blinded the surgeons conducting the operations, the anesthesiologists, and the anesthetists to the specifics of the intervention. Moreover, the details of the intervention remained unknown to the individual responsible for data analysis. The ward nurse, not involved in the patient’s care, received the assigned envelope upon reaching the postoperative ward. The nurse then took on the responsibility of unsealing the envelope. The research assistant handled the data collection, offering an unbiased approach to acquiring postoperative information. Every patient participating in the trial received the same anesthetic treatment. In order to prevent aspiration, omeprazole and metoclopramide were given intravenously 30 min before the surgery. A proficient laparoscopist performed all laparoscopic hysterectomies, using three to four ports, each with a diameter of 5 mm. The laparoscopist maintained the abdominal pressure at 15 mmHg throughout the process by introducing gas into the abdominal cavity at a high flow rate of 20 mL/min. After completing the surgical procedure, the surgeon regularly assisted in the passive deflation of the pneumoperitoneum. The surgeon accomplished this by exerting mild force on the abdomen, which facilitated the regulated discharge of CO2 via the surgical opening. Following the surgery, the postanesthetic care unit observed the patients for an hour before transferring them to the gynecologic ward. During the postoperative period in the gynecologic ward, patients in the intervention group were placed in a modified Trendelenburg position, tilted at a 20° angle, for a duration of 6 h. On the other hand, the control group maintained a supine posture. The modified Trendelenburg position is characterized by the patient lying flat on their back, with the head level with the body and legs passively elevated. To mitigate the possibility of aspiration, this research used the modified Trendelenburg position instead of the conventional Trendelenburg position. Additionally, we prohibited patients from ingesting food while in this posture. Data collection began when the patients arrived at the gynecologic ward, and further evaluations were conducted at 6, 12, and 24 h after the surgery. The assessments included evaluations of shoulder, upper, and lower abdomen pain, along with ratings for nausea and vomiting. All patients were provided naproxen for the treatment of postoperative pain. Morphine and paracetamol were given as additional pain relievers as necessary. In addition, metoclopramide, an antiemetic medication, was administered for individuals who were feeling nausea. The precise amount of analgesic and antiemetic drugs given during the first 24 h after the surgery was carefully documented. The main objective is to assess the severity of shoulder discomfort 6 h after the surgical procedure. The secondary outcomes include evaluating the severity of upper and lower abdomen pain, measuring scores for nausea and vomiting, and monitoring the use of pain-relieving and anti-nausea drugs in the 24 h after the operation. The Numerical Rating Scale (NRS) is used to evaluate pain levels, ranging from 0 (showing absence of pain) to 10 (marking the utmost intense pain). The evaluation of nausea/vomiting utilizes a four-point scale: 1 indicating the absence of nausea/vomiting, 2 indicating simply nausea, 3 indicating nausea and vomiting that necessitates medicine, and 4 indicating nausea and vomiting that requires more than one administration of medication. Pain and nausea/vomiting ratings are evaluated at 0, 6, 12, and 24 h after the surgery. The design of this investigation follows a two-sided randomized controlled trial with the objective of achieving a statistical power of 90% and establishing an alpha level of 0.01. According to Zeeni et al .’s study, the sample size was determined based on the anticipation of a 2-point reduction in the NRS for shoulder pain in the intervention group compared to the control group. This assessment was done 6 h after the operation.[ 10 ] The estimate included an estimate for a maximum dropout rate of 30%, which was expected due to potential complications such as patient intolerance of the modified Trendelenburg posture or the need for conversion to laparotomy. Consequently, the research was designed to include a total of 46 patients, with an equal distribution of 23 individuals in each group. We analyzed the acquired data using SPSS version 22. The data are presented as means ± standard deviation for continuous variables and as the median (minimum, maximum). Frequencies (expressed as percentages) are reported for categorical variables. The Student’s t -test was used to analyze normally distributed continuous data, whereas the Mann–Whitney U test was used for ordinal data. We applied either the Chi-square test or Fisher’s exact test to analyze categorical data, depending on the nature of the data set. P < 0.05 indicates a statistically significant difference.