Pharmacological management of acute pain post-tonsillectomy in the otorhinolaryngology department at Muhimbili National Hospital

Introduction

Tonsillectomy is defined as a surgical procedure for completely removing the palatine tonsil, including its capsule. In-ear, nose, and throat surgeries, tonsillectomy is the most common procedure carried out.¹

Post operative pain is a relevant occurrence following tonsillectomy and mismanagement of pain control has been reported in recent studies with no international standard pain therapy regime following tonsillectomy.^2,3 The occurrence of pain is influenced by various factors such as duration of procedure, type of anaesthetic used intraoperatively, timing and type of post operative analgesia.^4,5 In this study the timing and type of postoperative analgesia is of interest.

The numerical rating scale and visual analogue score are the most frequently used pain assessment tools offering reliable results and have been validated to be used in children from eight years and above.^6,7

Various pharmacological modalities have been employed in managing pain following tonsillectomy, such include drugs like opioids and non-opioids analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), local anesthetics, paracetamol, ketamine and adjuvants. Recent studies emphasize on multimodal approach with the use of different drugs and techniques to achieve better therapeutic benefits with less side effects.^8,9

Inadequacy of knowledge on pharmacological management post tonsillectomy particularly in developing countries lags behind efforts to reduce the burden of acute pain following tonsillectomy. The aim of this study is to determine postoperative pain management outcomes in patients who underwent tonsillectomy and encountered challenges in our setting; therefore, we may get a better insight and understanding on how to improve postoperative pain management in order to avoid complications.

Methods

Results

This study involved 72 patients who underwent tonsillectomy. The majority of patients were in the age group of 8–15 years, 50% (n = 36), with the median age of 16. Female patients contributed 73.6% (n = 53), with a female to male ratio of 2.8:1 (Table 1).

Discussion

Since tonsillectomy is one of the most commonly performed procedures, postoperative pain assessment is essential in the surgical patient care plan. Adequate post-operation pain management is important to prevent associated morbidity in patients, such as inadequate intake of oral liquids, recovery speed, and day to day activities.¹¹

Paracetamol was the commonest analgesia prescribed (37.5%), followed by a combination of ibuprofen and paracetamol (36.11%), the similarity is seen with a study done by Mogane et al. where 90% of children were prescribed paracetamol¹² and Warnock et al. where 60% of patients’ post-tonsillectomy were prescribed acetaminophen.¹³ Prescriptions were based on the surgeon’s preference in contrast to Fletcher et al. in a survey of post-operative pain where there was a room for patient-controlled analgesia with a predominance of paracetamol and subcutaneous morphine, 95.2% and 95.8% respectively.¹⁴ This is seen to be different from Tanzanian studies, where pethidine injection predominated by 50%, followed by tramadol.^15,16 The difference could be explained by the differences in the nature of surgeries where various surgeries such as abdominal, head, neck, chest surgeries, surgeon preference, availability of analgesics in the hospital and the fact that no study has been done to assess post-operative analgesia following tonsillectomy alone.

Moderate pain was experienced at six hours and 12 hours following tonsillectomy, with 55.6% and 65.3%, respectively. This was followed by significant pain reduction where 88.9% of patients had mild pain at 18 hours after initial analgesic administration. Similarly, a study by Sommer et al. showed moderate pain was experienced on day 0, but in contrast, the pain persisted until day four of follow up¹⁷; this could be explained by the fact that pain after adult tonsillectomy stays high until day seven when it begins to decline. The similarity is also seen with Warnock et al., where moderate pain was scored on the first postoperative day with decreased pain intensity on day 7 of follow up as well as Hui et al. where moderate pain was scored on day one, and none had pain on day 14 of follow up.^13,18

The differences in attaining pain relief exist among age groups and sex distribution in this study, although these differences were not statistically significant (p >0.05). An observation in this study showed that those aged above 24 years had less pain relief than those aged below, including children and young adults, by 96.6% versus 97–100%, although this difference is small, these findings appear to be similar to other previous studies where the pain was perceived more in adults than children.^19,20 This is probably due to tissue fibrosis from recurrent tonsillitis and the associated complications such as dehydration and prolonged healing time that occurs more in adults than children.²¹ However, all females attained pain relief compared to males (89.5%); which contradicts a study done in Korea by Kim et al., where males had less pain than females.²⁰ These findings were not statistically significant.

Pain score distribution was seen to be different with using different analgesics in this study, but these differences were not statistically significant (p >0.05). Pain reduction with combination drugs was seen to be more effective than single drug use; a similarity is seen in a study done in Tanzania.^16,22 This is because of the advantageous combined synergistic effect on pain reduction.

The combined effect of paracetamol and ibuprofen was seen with pain reduction from moderate pain (46.2%) and severe pain (53.8%) at six hours to mild pain at 18 hours (84.6%). A similarity is seen with other studies including a study done by Liu et al. where the pain was unresolved in only 9.6% of patients.¹⁹ The use of NSAIDs, particularly ibuprofen, resulted in pain reduction; as observed in this study, pain relief was severe (41.7%) and moderate pain (58.3%) at six hours to mild pain (100%) at 18 hours. The similarity is seen with a study by Jensen et al., where ibuprofen was shown to be effective in pain reduction.²² This observation is due to its anti-inflammatory effect and its longer duration of action (6–8 hours) in contrast to paracetamol (4–6 hours), although they have the same therapeutic range at the correct dosage, and it is safety in terms of fewer side effects. This is in contrast to a study by Jotic et al. where satisfaction in pain management was equal with the use of ibuprofen and paracetamol.¹⁰

Pain assessment among patients who were given paracetamol showed adequacy in pain control. Relief of pain at 18 hours was no pain (3.7%) and mild pain (88.9%) compared to 59.3% of patients who had moderate pain and 37% who had severe pain at six hours. In this study, paracetamol was seen to work well in pain reduction. In contrast with other studies, paracetamol was observed to provide inadequate pain control on its own, especially in the early postoperative period, because of its shorter half-life of 1.5–2.5 hours. Dose control in other studies was important as it was associated with acute hepatic necrosis by depletion of glutathione and its reaction to vital cellular constituents.²³ Therefore, it is seen to work best when combined with codeine²⁴ or with ibuprofen.²²

Our observation also showed that a combination of paracetamol or ibuprofen with diclofenac (NSAID) and/or tramadol (weak opioid) resulted in pain reduction from moderate pain (100%) with paracetamol and diclofenac to mild pain, and from moderate (66.7%) and severe (33.3%) pain with ibuprofen and diclofenac to mild pain (100%).This observation concurs with other studies where the use of tramadol was shown to have a better analgesic effect even when used on its own and has a lesser emetic effect than other opioids.²⁵ However, individual variability within the cytochrome p450 system influences its variability, and its use in pediatric patients is limited by studies.²⁶

There is evidence that, to date, there is no consensus on the appropriate analgesic, either single or in combination, to use following adult and pediatric tonsillectomy, given the bimodal pain pattern following tonsillectomy and its individual variation.²⁷

Conclusions

The findings in this study showed that the most commonly prescribed analgesic was paracetamol followed by a combination of paracetamol and ibuprofen.

The majority of patients who attained pain relief according to pain intensity score within 18 hours following tonsillectomy were those who were aged between 16–23 years with female predominance, these differences were not statistically significant.

The use of combined drugs such as ibuprofen + diclofenac, paracetamol + diclofenac and ibuprofen + paracetamol showed better pain control than single drug use, although these differences were not statistically significant. This could be influenced by the sample size of the studied population and individual variations in pain perception.

Consent

Written informed consent for publication of the patients’ details was obtained from the patients and parents or guardians of the patients.