Perioperative pain management in thyroidectomy: a cross-cultural perspective  

The management of perioperative pain in surgical patients has undergone much scrutiny and study. Adequate perioperative pain management can dramatically alter patient experience, hospital length of stay, and postoperative pain medication requirements. Especially in the wake of the opioid epidemic, there has been an emphasis on multimodal analgesia (MMA), including regional and systemic non-opioid strategies. MMA has been shown to improve postoperative outcomes, and its use has become increasingly utilized[1]. Despite this, many patients receive intraoperative and postoperative narcotics, even with relatively minor operations. 

There are many qualitative factors that can influence a patient’s experience of perioperative pain, including preoperative pain, anxiety, age, and type of surgery. Many of these factors are correlated with increased pain medication usage in the perioperative period[2]. While these factors have been well-studied, the intersection of culture and perioperative pain control has not been closely examined.  

Our study evaluates perioperative anesthesia and pain management strategies in a Low-to-Middle Income Country (LMIC) as compared to a High-Income Country (HIC), with the hypothesis that differences will exist both in anesthesia strategies and in patient pain perception in the perioperative setting.

This study included a retrospective analysis of two patient cohorts. The first cohort consisted of patients who received surgical care during a medical mission trip to Carmona, Cavite, Philippines in February 2024. These patients were selected consecutively based on the availability of complete data records. The second cohort was selected from the electronic medical record of a tertiary medical center in Memphis, Tennessee and included cases from September 2023 to February 2024. These cases were selected consecutively in reverse chronological order until the same number of cases were obtained, matching by procedure type (partial vs. total thyroidectomy) to ensure that operative complexity was similar between groups. No further matching was completed due to the size of available case volume. This approach was used to minimize selection bias and ensure comparable procedure cohorts. Baseline characteristics of age, gender, and operative indication were collected. 

 Institutional review board approval was obtained from both institutions.  Cases performed in the Philippines were categorized as LMIC, and those performed in the USA were categorized as HIC. Variables collected included patient demographics (age, gender), type of operation (partial or total thyroidectomy), indication (Graves disease, thyroid goiter, thyroid nodule, thyroid cancer), anesthesia modalities, narcotic use in morphine milligram equivalents (MME), and postoperative pain scores as recorded in the electronic medical record or paper medical records. Pain scores in the LMIC setting were determined with the Wong-Baker FACES Pain Rating Scale in Tagalog (0-10). Pain scores in the HIC setting were determined with the Numerical Pain Rating Score (0-10).

Due to small sample size, categorical variables were compared with Fisher’s exact test or the Fisher-Freeman-Halton exact test depending on the number of categories. Continuous variables were summarized as means or medians with interquartile range and were compared with Student’s t-test or Wilcoxon rank-sum test depending on distribution. A p-value < 0.05 was considered statistically significant. Statistical analyses were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA).

Twenty-two patients were selected for analysis in the LMIC setting within the study period, and these cases were matched with 22 cases in the HIC setting. Eight patients underwent total thyroidectomy and 14 underwent partial thyroidectomy in each cohort. The cohorts were each similar in age and gender, and for indication in total thyroidectomy. Surgical indication in partial thyroidectomy was significantly different in the LMIC group, who were more commonly diagnosed with goiter, as compared to the HIC group, who were more likely to have a nodule, as summarized in Table 1 (p 0.05).

All patients underwent general endotracheal anesthesia by either an anesthesiologist or certified registered nurse anesthetist (CRNA), and each physician and CRNA had been trained in the HIC setting. Patients undergoing total thyroidectomy in the LMIC setting received a median dose of 30 MME (IQR, 22.5 – 37.5) in the perioperative period, as compared to 77.5 MME (IQR, 50 – 105) for HIC patients (p = 0.004). A similar trend was observed in partial thyroidectomy, with 30 MME (IQR, 15-30) in LMIC patients and 50 MME (IQR, 40 – 80) in HIC patients (p = 0.002). These differences are driven by narcotic use both intraoperatively and postoperatively, as seen in Figure 2. 

Available anesthesia modalities were similar between the two settings, and included the following medication options.

• Intraoperative non-narcotic sedatives: propofol, ketamine, midazolam, dexmedetomidine
• Intraoperative non-narcotic pain medications: acetaminophen, ketorolac, lidocaine, dexamethasone
• Intraoperative narcotic pain medications: hydromorphone, morphine, fentanyl
• Post-anesthesia care unit (PACU) medications: intravenous narcotics, oral narcotics, non-narcotics
• Discharge medications: acetaminophen, tramadol, and oxycodone-paracetamol

 Providers in the LMIC setting more commonly used adjunctive ketamine and acetaminophen, whereas providers in the HIC setting more often used dexmedetomidine, intravenous lidocaine, dexamethasone, and hydromorphone. Local anesthesia was used in the LMIC setting but not the HIC setting. A comparison of all perioperative anesthesia strategies is summarized in Table 2. The difference in strategies can be clearly seen, but should be interpreted cautiously given the small sample sizes. These findings reflect the difference in practice patterns and resource availability, even when all anesthesia providers underwent similar HIC training. Overall, patients in LMIC settings received fewer intraoperative non-narcotic anesthetic modalities (3 vs 4, p<0.01) and less total MME (30 vs 60, p < 0.01), despite equivalent postoperative pain scores. 

This study found that patients who underwent thyroid surgery in both LMIC and HIC settings had comparable postoperative pain scores, despite less narcotic use and less diverse anesthesia modalities in LMIC patients. These results both complement and challenge the current understanding of perioperative pain management. There are many potential explanations for these findings, which will require further investigation to better understand. 

Cultural differences between the two patient populations are likely to play a role. Prior research has shown that cultural and ethnic background play a large role in pain perception, and that there are very different expectations for pain between all cultures[3]. Patients may also approach surgical care with a different set of expectations—particularly during mission trips, where the perceived value of receiving care at all may influence patient satisfaction and perception of pain. In contrast, HIC patients may expect complete relief of discomfort as a standard of care and may have a lower threshold of pain tolerance as a result. Interwoven with these expectations are the behaviors of the medical team. Physicians who work in systems where reimbursements are tied to patient satisfaction metrics may feel pressure to aggressively treat pain and utilize opioids to avoid patient complaints, despite studies showing that decreasing opioid prescriptions does not impact patient satisfaction scores in a meaningful way[4,5]. Physicians in LMIC and mission settings are not impacted by this system and so can focus more on effective resource management. 

Resource limitations are inherent to LMIC settings, which requires reliance on innovative therapies and efficiency of resource management. The data above demonstrates that local anesthesia is more commonly used in LMIC settings, suggesting that this easily available and relatively inexpensive modality may be used in place of more expensive systemic therapies as a strategy to manage resources. Local anesthesia also has a lower risk of systemic adverse effects and can reduce the need for perioperative narcotic use. 

These findings must be considered in the context of their collection. Pain is inherently subjective, and the two cohorts utilized different pain rating scales to evaluate postoperative pain. While the Numerical Pain Rating Score scale (used in the HIC setting) has been shown to be successfully translated across cultures, the FACES Pain Scale (used in the LMIC setting) has been shown to be more preferred when evaluating pain in developing countries[6,7]. While these tools are validated, and data shows strong correlation between the two scales, pain rating remains subjective and patient-reported outcomes using two different scales should warrant careful interpretation[8]. Additionally, it is important to consider that the distribution of case indication differed in patients undergoing partial thyroidectomy, with HIC patients more commonly having a nodule as compared to LMIC patients who had goiter. This difference may have influenced perioperative decision-making and confounded results due to differences in operative technique. Importantly, however, lower opioid use was seen in both total and partial thyroidectomy groups, suggesting that surgical technique may not completely explain these findings. Finally, long-term outcomes, such as outpatient pain scores, patient experience metrics, and long-term opioid dependence, were not collected, limiting our understanding of longitudinal effects of perioperative pain management.

Given the small sample size and observational nature of the study, the results should be interpreted cautiously and as hypothesis-generating instead of definitive. The findings do provide a framework for future work investigating the interplay between culture and pain management. While LMIC settings are often considered less resourced, which can sometimes be inaccurately equated to less effective, LMIC strategies may represent an opportunity for investigation of alternate practices. Further prospective and controlled studies are required to better understand the relationship between perioperative opioid use and pain outcomes across different settings.