Comparison of Trocar Site versus Trocar Site Plus Intraperitoneal Instillation of Local Anesthetic for Shoulder Pain Following Laparoscopic Abdominal Surgery.

Background: Laparoscopic surgery in recent times has noteworthy advantages over conventional surgery, yet recovery is prolonged due to debilitating shoulder tip pain (STP) and operated site pain. Various studies have compared the effect of trocar site, intraperitoneal instillation of local anesthetic (LA) for pain relief while only a few studies have tested the combination of these two techniques. Hence, this study was undertaken to compare the combination of these two techniques versus trocar site alone for STP particularly. Subjects and
Methods: This prospective, randomized, comparative study was conducted on 52 patients who were undergoing laparoscopic abdominal surgery. The patients were allocated into either of the two groups. Group I (n = 26): trocar site infiltration (20 mL) and intraperitoneal instillation (20 mL) of 0.25% levobupivacaine and Group II (n = 26): trocar site infiltration (20 mL) of 0.25% levobupivacaine and saline (20 mL) intraperitoneally. Postoperative STP was the primary outcome while surgical site pain, nausea, and vomiting were secondary outcomes.
Results: There were no statistically significant differences between the groups with regard to shoulder pain, surgical site pain, total rescue analgesics, and incidence of nausea and vomiting (P > 0.05).
Conclusion: Trocar site infiltration with intraperitoneal instillation of LA or trocar site infiltration alone was found to be equally effective. However, we suggest that it is better to provide a combination of trocar site infiltration plus intraperitoneal instillation of LA if we have to restrict opioid usage such as in day-care surgeries. Copyright:

INTRODUCTION

Laparoscopic surgery has considerable advantages over conventional laparotomy, owing to the minor surgical trauma due to miniature incisions and lesser wound-related pain, thereby enabling prompt recovery, early ambulation, and briefer hospital stay.[1] Pain that is experienced after laparoscopy surgery is of a different nature and less intense when compared to that observed after conventional surgery.[2] The main postoperative problem that patients usually have after laparoscopic surgery is pain at the operated site, which increases on coughing or during mobilization.[2]

Pain after laparoscopic surgery has many components. Of which, the most common would be the visceral component due to tissue injury during surgical handling and referred pain, which is attributed to pneumoperitoneum causing phrenic nerve irritation as the innervation is shared with the nerves innervating the shoulder. Apart from these two pain generators, there is also a somatic component caused due to abdominal wall incisions made for the insertion of trocars. Therefore, extensive research has been carried out exploring different modalities of pain management post laparoscopic surgery.[2] However, shoulder tip pain (STP) is the most typical undesirable effect after laparoscopic procedures which itself could be due to multiple factors.[1]

Numerous studies have been devised to try different combinations of analgesic techniques to decrease the occurrence and severity of shoulder pain after laparoscopic surgery. Various methods studied include gradual insufflations at lesser pressures, usage of gases such as helium or argon to create pneumoperitoneum, prewarmed gas, gasless laparoscopy, multimodal analgesia, subdiaphragmatic local anesthetic (LA) irrigation, subdiaphragmatic suction, LA infiltration over the incision site, and instillation of LA solution into the peritoneum.[12]

Many studies have tested the efficacy of trocar site infiltration, intraperitoneal instillation of LA for visceral and shoulder pain,[234567] while only a few studies investigated the combination of preincisional subcutaneous infiltration (at trocar sites) and intraperitoneal instillation of LA.[8910] Hence, this study was designed to compare this particular combination with trocar site infiltration alone for pain relief after laparoscopic procedures more particularly STP.

SUBJECTS AND METHODS

This prospective, randomized, controlled double-blinded study was conducted after obtaining approval from the Institutional Ethical Committee (IEC No. 2017/343). The trial was registered in Clinical Trial Registry-India, before starting enrollment of patients (CTRI/2018/01/011208). A total of 52 patients between 18 and 60 years of age, the American Society of Anesthesiologist (ASA) physical status class I and II, posted for elective laparoscopic abdominal surgeries such as cholecystectomy, appendectomy, ovarian cystectomy, hysterectomy, etc., under general anesthesia were included in the study. Patients with physical status ASA class III and above, surgery duration >2 h, preexisting shoulder pain and those not willing to participate in the study were excluded from the study. The study protocol was explained to all patients in their own language and informed and written consent was obtained.

All patients were kept nil per oral for 8 h before the start of surgery and were premedicated with tablet ranitidine 150 mg per oral and tablet alprazolam 0.25 mg per oral night before surgery. Two groups were randomized by a computer-generated list of random numbers, and patients were divided into Group I – Group I (Study) and Group II (Control) and Group II . After shifting to the operation theater on the day of the surgery, large-bore intravenous access of size 18G was established and lactated Ringer's solution was started at 10 mL.kg−1. Patients were then premedicated with 0.2 mg of glycopyrrolate and 4 mg ondansetron intravenously which was followed by morphine 0.1 mg.kg−1 and midazolam 0.03 mg.kg−1.

Induction was done using propofol 2 mg.kg−1 intravenously, neuromuscular blockade with vecuronium 0.1 mg.kg−1, after check ventilation. Intubation was done with the appropriate size of the endotracheal tube, connected to the ventilator on circle system, anesthesia was maintained with 1% isoflurane, and nitrous oxide and oxygen were kept in the ratio of 65:35. Intraoperatively, heart rate, respiratory rate, continuous electrocardiogram (ECG), oxygen saturation, and noninvasive blood pressure were monitored along with end-tidal carbon dioxide, maintained between 35–45 mmHg. Once pneumoperitoneum was established, after insertion of ports, intra-abdominal pressure (IAP) of 12–14 mm Hg was maintained. At the end of surgery before removing the primary port, patients were given the following as per group allocation:

Group I (Study) – 0.25% levobupivacaine 20 mL for infiltration at trocar sites and 20 mL for intraperitoneal instillation through the primary port before removal of the port

Group II (Control) – 0.25% levobupivacaine for infiltration at trocar sites and 20 mL of saline for intraperitoneal instillation through the primary port before removal of the port.

Residual neuromuscular blockade was reversed with injection neostigmine 50 mcg/kg and injection glycopyrrolate 20 mcg.kg−1, the patient was extubated after the return of the airway protective reflexes, spontaneous breathing, and regaining the adequate level of consciousness. Thereafter, patients were observed for 1 h in PACU and shifted to surgical ICU where they were evaluated for pain 48 h postoperatively at 4th hourly intervals. A standard 10 cm Visual Analog Scale (VAS) was used to monitor right shoulder pain – in which 0 is no pain and 10 is the worst imaginable pain. Injection diclofenac 75 mg was administered intramuscularly for shoulder and surgical site pain, following which the time and number of rescue analgesics were also noted to make sure it does not exceed the capping dose of 150 mg per 24 h. Postoperative nausea was monitored using the 10 cm (VAS) on of 0–10 where 0 is no nausea and 10 is severe nausea and the number of episodes of vomiting was noted and recurrent episodes were treated with ondansetron 4 mg intravenously. Patients were monitored postoperatively for 48 h for the above mentioned parameters.

RESULTS

A total of 52 patients were enrolled with 26 patients each in Groups I and II. Eight patients were excluded (operating time exceeded 2 h in five patients, conversion to laparotomy in three patients). The demographic details of the patients such as age, sex, and weight were comparable between the two groups.

The mean shoulder pain scores between the two groups were not statistically significant at any point of time during the postoperative period [Table 1]. Similarly, the mean surgical site pain scores were also not statistically significant at any point of time during the postoperative period [Table 2]. The mean first rescue analgesia was found to be 0.26 ± 0.764 in the experimental group and 0.33 ± 1.209 in the control group (P = 0.7889). Furthermore, the mean total rescue analgesia was found to be statistically insignificant between the two groups with P = 1.000 [Table 3].

Table 1

Distribution of shoulder pain score between the two arms of the study participants

Time interval after surgery (h)	Mean (shoulder pain score)±SD		P
	Trocar site+ intraperitoneal instillation of levobupivacaine (Group I)	Trocar site infiltration of levobupivacaine (Group II)
At 4	0.1±0.3	0.6±2.0	0.1887
At 8	0.1±0.3	0.4±1.5	0.2530
At 12	0±0	0.2±0.8	0.1788
At 24	0±0	0±0	-
At 48	0±0	0.2±0.9	0.3219

SD=Standard deviation

Table 2

Distribution of surgical site pain between the two arms of the study participants

Surgical site pain (h)	Mean±SD		P
	Trocar site+intraperitoneal infiltration (Group I)	Trocar site alone (Group II)
At 4	1.8±1.7	1.1±2.1	0.2119
At 8	1.3±1.4	0.8±1.4	0.1562
At 12	0.8±1.2	0.4±1.3	0.2445
At 24	0.5±0.9	0.2±0.7	0.1292
At 48	0.2±0.6	0.03±0.2	0.1199

SD=Standard deviation

Table 3

Comparison of total rescue analgesics between the groups

Group	Mean±SD	T	df	P
Trocar site+intraperitoneal infiltration	0.14±0.45	0.000	52	1.000
Trocar site alone	0.14±0.60

SD=Standard deviation

The mean nausea score at 4 h and 8 h were, respectively, 0.59 ± 1.421 versus 0.56 ± 1.476 (P = 0.0.9255) and 0.07 ± 0.385 versus 0.19 ± 0.681(P = 0.4640). The nausea score was 0 in both groups during the subsequent hours. The mean episodes of vomiting at 4 h between the two groups were comparable (P = 1.000). There were no episodes of vomiting at or after 8 h in both groups.

DISCUSSION

Etiology for pain after laparoscopic abdominal surgery can be multifactorial, with a somatic and visceral component. Referred pain is a consequence of pneumoperitoneum. In our study, the effectiveness of a combined analgesic technique of trocar site infiltration and intraperitoneal instillation of LA has been evaluated. Unlike most of the previous studies that emphasized postlaparoscopic abdominal or surgical site pain, we focused on STP mainly by comparing the combination versus the trocar site alone.

A few studies have analyzed the efficacy of combined trocar site infiltration and intraperitoneal instillation of LA and the results are conflicting.[8910] Karaman et al. compared the effects of the combination of preincision infiltration of trocar sites plus intraperitoneal instillation of levobupivacaine 0.25% after pneumoperitoneum with intraperitoneal instillation alone for postoperative pain management following laparoscopic cholecystectomy and found that either the combination or intraperitoneal instillation of LA alone reduced the shoulder pain significantly than the control group.[8] Similarly, Louizos et al. also observed that this combination was better than other groups as well as the control group.[9] In contrast, Hilvering et al. observed no difference between this combination and the control group.[10] In our study, there was no significant difference between the two groups. This could be because we have compared the combination with trocar site infiltration and without any control group receiving placebo for both techniques. There is also a possibility of some amount of LA leaking into the peritoneal cavity during infiltration at trocar sites resulting in shoulder pain relief.[11]

Karaman et al. have also observed that the combination has significantly reduced the rescue analgesics requirement when compared to the intraperitoneal instillation alone or the control group.[8] Another study has observed that trocar site infiltration reduced the visceral pain significantly when compared to the intraperitoneal instillation or the control group.[2] However, it could not reduce the incidence of STP as much as that of intraperitoneal instillation as per the results of that study and it was misinterpreted.[11] The amount of LA present either in the peritoneal cavity or under the subdiaphragmatic region would play a major role in reducing STP.[11] A recently published study also observed that the subdiaphragmatic irrigation with sodium bicarbonate significantly reduced the STP, but not the incisional or visceral pain when compared to the control group in patients undergoing laparoscopic total hysterectomy.[12]

STP has some characteristic features in its origin and methods adopted for its relief.[2] Although many techniques are adopted to provide relief from STP,[2] we wanted to mainly study the impact of intraperitoneal infiltration of LA in addition to trocar site infiltration on STP. While our findings were not as per our hypothesis, we still believe that this combination would be a better option, particularly for day-care surgeries as STP might be a major hindrance to discharge some patients on the same day.

Limitations

The main limitation of our study is that we have not included a placebo group getting only normal saline for both trocar site infiltration and for intraperitoneal instillation. We did not do so because of ethical considerations. Hence, we made the LA injection at the trocar sites alone and used the placebo for the intraperitoneal infiltration in the control group.

CONCLUSION

The combination of trocar site infiltration and intraperitoneal instillation of LA or trocar site infiltration alone was found to be equally effective in the management of postoperative shoulder pain and surgical site pain following laparoscopic abdominal surgery. However, we suggest that it is better to provide a combination of trocar site infiltration plus intraperitoneal instillation of LA if we have to restrict opioid usage such as in day-care surgeries.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.