Time Characteristics of Shoulder Pain after Laparoscopic Surgery.

Minimally invasive is one of the principles of modern surgery. In recent surgical practice, laparoscopy is replacing conventional laparotomy because of several of its advantages. Over 8000 laparoscopic operations are performed in our hospital every year. A substantial number of patients complain of postlaparoscopic shoulder pain (PLSP), which can be more uncomfortable than abdominal incisional and visceral pain after surgery. 1 To prevent and treat it better, it is necessary for clinicians to understand its characteristics.

Because of the tumor or serious abdominal adhesion, 4 patients changed to open surgery. One case underwent emergency operation due to postoperative abdominal hemorrhage. The 437 patients completed the study. Baseline characteristics of the 437 patients are shown in Table 1 . Our study showed a 68% (297/437) incidence of PLSP. Over 90% of these patients developed shoulder pain on the first day after surgery. Demographic and Clinical Characteristics of Postlaparoscopic Shoulder Pain in 437 Study Patients Data are presented as means [interquartile range], mean ± SD or numbers (%). We only looked at the literature on the incidence and (or) severity of shoulder pain at different time points after operation, rather than the literature with only one observation time point. We screened 41 articles. Twenty-seven of them met our requirements. 2 – 28 The observation time points of these studies included 12–24 hours or the first day after operation, and at least one time point before this time point. Seven of them observed the incidence of PLSP at different times, and five reported that the incidence of PLSP peaked at 24 hours after operation ( Table 2 ). Two articles did not provide the incidence of shoulder pain at different time points in the control group and the intervention group. 100% (5/5) of the studies found that the intervention did not change the time characteristics of shoulder pain incidence. Among them, 26 articles observed the severity of PLSP at different time points. A total of 55 groups were observed. The shoulder pain of 30 groups reached the peak at 12–24 hours or the first day after operation ( Table 3 , Table 4 ). Although the interventions in these studies were statistically significant compared to the control group, 70.8% (17/24) of the studies found that the intervention did not change its time characteristics based on the study of shoulder pain severity. Systematic Review of the Literature Values are meant as median (SD) unless indicated otherwise. Overall: the total incidence of PLSP during postoperative observation (in each group, the number of patients with VAS = 0 at each time point was recorded to evaluate the overall incidence of PLSP); LPP group: low pneumoperitoneum pressure group; SPP group: standard pneumoperitoneum pressure group. a The patient's shoulder pain reached its peak. Systematic Review of the Literature Values are meant as median (SD) unless indicated otherwise. LPP group: low pneumoperitoneum pressure group; SPP group: standard pneumoperitoneum pressure group. VAS: visual analogue scale; NRS: numerical rating scale. a The patient's shoulder pain reached its peak. b Unable to determine the exact value from the original text. Systematic Review of the Literature a The patient's shoulder pain reached its peak. b Unable to determine the exact value from the original text.

The results show that shoulder pain after gynecological laparoscopic surgery has obvious temporal characteristics, which is significantly different from incision and visceral pain after laparoscopic surgery. Clinicians should be familiar with the time characteristics of its occurrence. To fully highlight the advantages of laparoscopic surgery, a multifactor approach may be needed to solve PLSP in future research. This method needs to fully consider the temporal characteristics of PLSP.

Laparoscopic surgery has obvious advantages in the diagnosis and treatment of gynecological diseases. Minimally invasiveness is one of the most important characteristics of laparoscopic surgery. Minimally invasive surgery does not mean only a small incision. The patients hope that after laparoscopic surgery, the pain will be relieved, the requirement of analgesia will be reduced, the length of hospital stay will be shortened, the recovery of activity will be early, and the incidence of complications will be reduced. 1 , 29 Most of these advantages are achieved by reducing pain after surgery. However, the pain after laparoscopic surgery has not been completely eliminated. Many patients may feel shoulder pain, which is more uncomfortable than abdominal incision and visceral pain, and is rarely seen in traditional laparotomy. Because most patients think shoulder pain has nothing to do with surgery, it makes them more anxious. This may lead to discomfort and poor quality of life after laparoscopic surgery, and greatly reduce patient satisfaction. Therefore, this will not be conducive to highlighting the advantages of laparoscopic surgery. As far as we know, many interventions and comparative studies on reducing shoulder pain after gynecological laparoscopic surgery have been documented in the British literature so far. Our clinical observations and many previous studies have shown that the temporal characteristics of shoulder pain after gynecological laparoscopic surgery are significantly different from those of incision and visceral pain after surgery. Visceral and incision pain was more severe on the day after operation, and then gradually reduced. However, PLSP began to become serious in 12–24 hours (or the first day after operation). More importantly, most clinical studies have found that almost all interventions do not change the temporal characteristics of shoulder pain after laparoscopic gynecologic surgery. Although the specific mechanism of PLSP is still controversial, most scholars believe that it is caused by the stimulation of the phrenic nerve by residual gas in the abdominal cavity after operation. In our hospital, all our patients began to get out of bed on the first day (12–24 hours) after surgery. Most of the patients began to have shoulder pain after getting out of bed for the first time. It may be that the location of gas accumulation in the abdominal cavity changes with body position, and then cause shoulder pain. In addition, among all kinds of pain after laparoscopic surgery, shoulder pain has the least response to nonsteroidal anti-inflammatory drugs or opioid analgesics. Although morphine can control other types of pain, such as incision and visceral pain, it cannot effectively control PLSP. This may be related to the unreasonable timing of our medication. 30 , 31 We should choose the administration scheme that matches the temporal characteristics of PLSP.

This study was reviewed and approved by the Institutional Review Board and was registered with the Chinese Clinical Trial Registry. We studied 442 inpatients (ASA level I) that underwent elective gynecological laparoscopic surgery. Exclusion criteria included chronic pain syndromes such as fibromyalgia or neck and shoulder pain, history of long term use of daily opioids, allergies to medications used in this study (such as fentanyl, propofol, midazolam), impaired cognitive function or inability to understand the study protocol, communication barriers, unstable cardiovascular disease and hypertension, central nervous system disease, endocrine system diseases, and liver and kidney dysfunction. All patients received similar general anesthetic and surgical regimens. No premedication was used. Heart rate, arterial blood pressure, and oxygen saturation were monitored in all patients on arrival at the anesthetic room. General anesthesia was induced with midazolam (0.1 mg/kg), fentanyl (4 μg/kg), and propofol (1–2 mg/kg). Cisatracurium infusion was used to facilitate tracheal intubation (0.15 mg/kg) and obtain intraoperative muscle relaxation. Anesthesia was maintained with oxygen in air (1:2), sevoflurane, propofol, and remifentanil. Minute ventilation was adjusted in accordance with the arterial CO 2 pressure in the exhaled air (PetCO 2 ). Ondansetron (8 mg) was administered intravenously by anesthesiologists to minimize postoperative nausea and vomiting when the surgeons began to close the umbilical trocar sites. At the end of surgery, neuromuscular relaxation was reversed pharmacologically using atropine and neostigmine. All patients were set in the lithotomy position and trendelenburg position during the operation. Laparoscopy was performed with abdominal insufflation of CO 2 (unheated, unhumidified) at 12-mm Hg using a standard automated insufflator. All operations were conducted by experienced laparoscopic surgeons using the standard technique with one 10-mm and two 5-mm trocars. The CO 2 was evacuated at the end of the procedure by manual compression of the abdomen with open trocars. All patients were kept for observation in the PACU until their condition was stabilized before shifting them to their designated wards. The following prophylactic analgesic standard treatment was used: intravenous propacetamol (1 g) was used approximately 20 min before the end of surgery, and either intravenous pentazocine (30 mg in the PACU) or orally ibuprofen sustained release capsules (300 mg in the ward) were administered on demand. All patients were assessed with visual analogue scale (VAS). We evaluated the shoulder pain before the patients left the PACU and at 6, 12, 24, 48, and 72 hours after surgery. The review has been performed by a search on PubMed, Medline, and OVID with the key words: “shoulder pain”, “laparoscopy”, “laparoscopic surgery”, “gynecologic surgery”, “gynecology”, “endoscopic”, “pain”, and “postoperative pain”. We only searched English literatures published before Jun 2020.