Tonsillectomy, with or without adenoidectomy, is effective in relieving pediatric sleep-disordered breathing-a term that describes a spectrum of obstructive disorders, ranging from snoring to obstructive sleep apnea. It can reduce the incidence of sore throat in children who have frequent throat infections and may be effective in treating children with peritonsillar cellulitis or abscesses. In addition, tonsillectomy plays a role in preventing the recurrence of rheumatic fever and in controlling chronic pharyngeal carriage of group A [beta]-hemolytic streptococci. Nevertheless, despite a century of use and refinement, tonsillectomy remains a traumatic experience for children and their families.
In the best of hands, tonsillectomy has a 2% to 4% risk of immediate or delayed hemorrhage1 and a death rate of one in 35,000.2 Many children who have this surgery experience separation anxiety and night terrors; postoperative edema, dysphagia, and weight loss are common sequelae. Despite pharmacologic advances in treating postoperative nausea and vomiting, both are common after tonsillectomy. Although the pain following tonsillectomy varies from child to child, it is typically prolonged, relatively constant, and rated by most children as moderate to severe in intensity even when it is treated with nonopioid and opioid analgesics.3, 4
This article explores the causes of posttonsillectomy pain. It reviews evidence-based best practices for mitigating this pain through both pharmacologic and nonpharmacologic interventions used in the hospital and in outpatient settings. In addition, it provides information about patient and family education and ways to improve medication adherence.
THE MECHANISM OF POSTTONSILLECTOMY PAIN
There has been remarkably little research into the mechanism of posttonsillectomy pain. Much information in this area comes to practitioners by way of analogy, referencing burn literature on wound healing at the cellular level and the role of inflammatory mediators.5
Tonsillectomy may damage tissue in a number of ways. The retractor, which is used to expose the oropharynx, compresses the tongue, produces venous congestion, and may injure sensory nerves (see Figure 1). The electrosurgical devices commonly used to excise the tonsils cause thermal damage to surrounding tissues, leading to acute inflammation and edema. After tonsillectomy, because the pharyngeal wound is left open, nerve pain fibers are exposed to hypotonic solutions and mechanical trauma from swallowed food. Related pain is most severe immediately after surgery and gradually diminishes over the ensuing days.
All tonsillectomy wounds become inflamed and infected.6 Within 24 hours of surgery, a thick white coating of fibrin and inflammatory cells appears in the tonsillar fossae, and the uvula and pharyngeal wall become edematous (see Figure 2). Inflammation intensifies between the third and fifth postsurgical days and may be associated with a transient increase in pain (see Figure 37, 8). Eventually, a fibrin clot fills the tonsillar fossae. It peels away at the start of the second postsurgical week, as surrounding mucosa grows in to cover raw muscle and granulation tissue. Usually, the newly formed epithelium completely lines the tonsillar fossae within two weeks of surgery, at which point severe pain dissipates, though some stiffness and referred ear pain may persist for weeks thereafter. The tonsillectomy and adenoidectomy operation can cause pain at sites other than the throat, including the head, stomach, tongue, ears, and lips.9
Some evidence suggests that intracapsular tonsillectomy (tonsil reduction), which produces a smaller wound than the classic extracapsular tonsillectomy (total tonsil excision), causes less postsurgical pain and heals faster.10, 11 A growing body of evidence supports intracapsular over extracapsular tonsillectomy in children whose indication for surgery is upper airway obstruction, and surgical outcomes for both procedures are comparable in reducing symptoms of obstructive sleep apnea and sleep-disordered breathing.12 The need to follow up intracapsular tonsillectomy with complete tonsil excision because of regrowth was experienced by fewer than 1% of patients in a recent study.13 In our clinical experience, children whose indication for tonsillectomy is recurrent sore throat seem to have more postsurgical pain than those whose indication is tonsillar hypertrophy, regardless of the type of tonsillectomy surgery they undergo.
Beyond physiologic considerations, the pain associated with tonsillectomy has an important emotional component. Perioperative anxiety may intensify the posttonsillectomy pain, and parental anxiety can be transferred to children.14, 15 Racial and ethnic differences have also been found to affect the experience of posttonsillectomy pain, with one prospective, observational study finding that black children experienced significantly more posttonsillectomy pain than white children and that white children experienced significantly more opioid-related adverse effects.16
PHARMACOLOGIC PAIN MANAGEMENT
Intraoperative medications. Short-acting iv opioids are prophylactically administered during surgery to reduce pain in the immediate postoperative period. Evidence regarding the use of a local anesthetic, such as lidocaine spray applied to the tonsillar fossae, is conflicting and at best suggests a modest reduction in immediate posttonsillectomy pain.17, 18 The pharyngeal anesthesia associated with these agents is frightening to some children and nerve blocks can cause severe upper airway obstruction.19 Typically, a single dose of an intraoperative steroid (usually iv dexamethasone 0.5 mg/kg) is used to decrease postoperative nausea and vomiting, and may have a favorable effect on swelling and pain as well. By contrast, routine perioperative antibiotics have shown no benefit in reducing pain or other posttonsillectomy morbidity.20, 21 Similarly, chemical or biologic coatings (such as sucralfate or a hemostatic matrix sealant) have not proven effective in protecting the tonsillar fossae following surgery.22
Opioid analgesics. Oral analgesics form the cornerstone of posttonsillectomy pain control. Although widely prescribed, acetaminophen with codeine has not demonstrated superior pain control over acetaminophen alone.7 In a clinical trial of 80 children who had undergone tonsillectomy and received the standard weight-based doses of acetaminophen with codeine for the first three days at home, the medication failed to provide effective analgesia.4
Another consideration is the metabolism of codeine to morphine in children, which occurs in the liver through the actions of the cytochrome P-450 (CYP) 2D6 isozyme. Although most children have normal CYP2D6 activity and their response to codeine is as expected, a substantial minority have CYP2D6 activity that is higher or lower than normal, potentially resulting in an excessive or inadequate response to codeine.23 While codeine provides little or no benefit to slow metabolizers, its use in ultrarapid metabolizers is potentially dangerous, as it may produce suddenly high serum levels of morphine, resulting in excessive sedation, respiratory depression, and other adverse effects.
In August 2012, the U.S. Food and Drug Administration issued a strongly worded safety announcement regarding the use of codeine after tonsillectomy or adenoidectomy, citing concerns about the unpredictable metabolism of this agent and related incidence of morphine toxicity in children who are ultrarapid metabolizers (a group estimated to represent between 1% and 7% of the general pediatric population, and up to 29% of certain African pediatric populations).24 This warning was followed in 2013 by a boxed warning declaring that the use of codeine after tonsillectomy or adenoidectomy is contraindicated.25
It is theoretically possible to avoid the CYP2D6 dilemma by substituting oral morphine, either alone or in combination with acetaminophen or a nonsteroidal antiinflammatory drug (NSAID). Unfortunately, very little is known about the pharmacokinetics of oral morphine in children,26 and fixed combinations of these drugs are not readily available. The practicality of this approach is further limited by the fact that morphine is more tightly regulated by the U.S. Drug Enforcement Administration than codeine.
The other commonly used alternative oral opioids, oxycodone (OxyContin and others) and hydrocodone, like codeine, are metabolized by CYP2D6. The clinical study of these drugs has been less extensive than that of codeine, but the use of hydrocodone in combination with acetaminophen (Vicodin and others) has been advocated as an effective alternative opioid for managing pediatric posttonsillectomy pain.27, 28 Unlike codeine, a relatively weak [mu] agonist whose analgesic action depends significantly on metabolic conversion to morphine, hydrocodone is believed to be primarily responsible for its observed analgesic effects (that is, active metabolites play a minor role in its analgesic action).29 We do not know whether slow metabolizers will have reduced analgesia when treated with hydrocodone or if ultrarapid metabolizers may risk toxicity with normal doses.30 Although both hydrocodone and oxycodone are used to manage pain in adult patients following tonsillectomy and adenoidectomy, there is no evidence to support the use of oxycodone to manage posttonsillectomy pain in children. If oral opioids are prescribed for posttonsillectomy pain, provider awareness and parental education are critical to ensure that early signs of overdose are immediately reported to the prescribing practitioner.
Nonopioid analgesics. A renewed focus on nonopioid oral analgesics for posttonsillectomy pain management, including acetaminophen and NSAIDs, has been prompted by concerns that opioids contribute to postoperative nausea, vomiting, and constipation and may worsen respiratory depression in children with obstructive sleep apnea.31
Acetaminophen is widely used and considered safe at normal doses.32 When used alone, however, it may provide inadequate analgesia for posttonsillectomy pain.3, 33 Acetaminophen's therapeutic index is narrow, and at higher doses the drug may cause hepatic toxicity.34 Since a number of over-the-counter remedies contain acetaminophen, it is important to remind parents to check the labels on all medications they give their child to avoid exceeding the maximum safe dosage of acetaminophen-for children under 12, 10 to 15 mg/kg every four to six hours, not to exceed five doses (50 to 75 mg/kg) in 24 hours; for children 12 and older, 650 to 1,000 mg every four to six hours as needed, not to exceed 4,000 mg in 24 hours.
The use of NSAIDs alone or in combination with acetaminophen is increasing. There is evidence that NSAIDs, such as ibuprofen, diclofenac, ketoprofen, and ketorolac, are effective analgesics in children.35 Although for many years, otolaryngologists were reluctant to use NSAIDs after tonsillectomy for fear of platelet inhibition and postsurgical hemorrhage, a 2010 update of a 2005 review from the Cochrane Collaboration found that NSAIDs (other than aspirin and cyclooxygenase-2 inhibitors, which are not recommended for children and were not studied in the reviewed trials) did not significantly alter postoperative bleeding compared with placebo or other analgesics.36 The updated review analyzed data from 15 randomized controlled trials that included more than 1,000 children. Based on this evidence, the 2011 American Academy of Otolaryngology-Head and Neck Surgery Clinical Practice Guideline on Tonsillectomy in Children states that ibuprofen can be used safely for pain control after adenotonsillar surgery.37
Inadequate administration of prescribed medication by caregivers has been cited as a cause of poor postoperative pain control.38 To address this issue, the use of around-the-clock regimens for postoperative analgesic administration has been advocated. Of the four clinical trials evaluating this approach in children who have undergone tonsillectomy,3, 4, 27, 28 only one study of around-the-clock acetaminophen with hydrocodone resulted in lower pain scores than as-needed dosing.28 Whether incomplete pain relief in these studies was owing to the dosing schedule or the choice of drug (acetaminophen, acetaminophen with codeine, rofecoxib, or hydrocodone) is unclear.
PATIENT AND FAMILY EDUCATION
In addition to effective analgesia, the prevention and management of tonsillectomy pain requires perioperative education to manage expectations, increase understanding, and promote attentive family care (see Table 1).
In the past, patient education about tonsillectomy pain was often withheld for fear of causing anticipatory anxiety. Today, there is evidence that education may help in controlling postoperative pain.39 In a prospective study involving 60 children undergoing tonsillectomy (30 assigned to receive an age-appropriate patient education booklet and 30 assigned to standard care), 96% of children in the intervention group reported that preoperative pain education, which included learning about the 0-to-10 numeric pain intensity scale, helped with their postoperative pain. In addition, 91% of children in the standard care (control) group reported that it would have been helpful to learn about the numeric pain intensity scale before surgery.
Establishing a pain treatment plan requires advance planning on the part of the physician, nurse, parents, and if developmentally appropriate, the patient.40, 41 Discharge instructions should be provided prior to the day of surgery to allow time to prepare for home care.42, 43 Important information may need to be repeated because parents may not remember everything they are told during the preoperative period.40
Several pain assessment tools, such as the Wong-Baker FACES Pain Rating Scale, have been validated for use in a pediatric population, and both children and parents may benefit from learning to use these tools. Depending on the child's age and ability to communicate, pain may be assessed using self-report or behavioral observation, with self-report being the preferred assessment, if feasible.
Instructional methods. Children and parents alike express a desire for information on pain management.39, 44 Limited studies have examined the relative effectiveness of different instruction methods for children undergoing outpatient tonsillectomy.43, 45
An illustrated children's book about a cartoon character undergoing tonsillectomy was reported by mothers, but not by nurses, to reduce distress in children ages two to 10 who were preparing for tonsillectomy or adenoidectomy.46 A pain education booklet for children ages seven to 13 was reported by children to have helped them deal with pain after tonsillectomy or adenoidectomy, although their pain scores were not lower than those in a control group who did not receive the booklet.39 A recent study of adolescents undergoing tonsillectomy found that an Internet presurgery preparation, presented in a "peers teaching peers" conversational format, increased patient satisfaction and knowledge acquisition but did not reduce anxiety or postoperative pain outcomes.43 While many children may benefit from online access to information, significant variability exists in the reliability and usability of Web-based resources available to parents and children undergoing tonsillectomy, and clinicians should assess available information and direct families to credible Web sites.
Results of two randomized clinical trials have suggested that a booklet may be an effective means of standardizing discharge teaching for parents of children undergoing adenotonsillectomy, particularly if it instructs parents to provide around-the-clock medication.4, 28 These investigations found that children whose parents were provided with printed instructions that recommended around-the-clock medication administration-and also described the expected course of postoperative pain, the rationale for aggressive pain management, and methods for facilitating analgesic administration at home-received more of the prescribed opioid than those whose parents received printed instructions recommending that they administer the drug "every four hours, as needed." On the other hand, a study evaluating the use of illustrated informational handouts in helping parents distinguish between expected postoperative symptoms and complications requiring medical evaluation found that the handouts had no significant effect in reducing the volume of after-hour phone calls to the surgeon.47
Studies evaluating the efficacy of various counseling modalities in helping the parents of children undergoing adenotonsillectomy to retain knowledge of surgical risks have reported conflicting results.48, 49 One study found that parents who received a detailed handout during counseling demonstrated significantly improved retention compared with parents who received only standard informed consent counseling but no handout.49 Another study found no difference in retention scores achieved by parents who received standard oral counseling, standard counseling plus a printed handout, or standard counseling plus video instruction.48 More research is needed to determine which educational interventions are most successful in improving the postoperative course of children undergoing tonsillectomy.
IMPROVING MEDICATION ADHERENCE
Failure to provide sufficient analgesia for children's posttonsillectomy pain after discharge remains a significant problem.50-54 Optimal use of pain medication after tonsillectomy is essential in reducing such associated complications as dysphagia, decreased oral intake, and dehydration.9, 37, 55
Barriers to prescribed medication adherence are complex and varied, so a multifaceted approach is needed to improve adherence. Nurses and physicians can promote medication adherence by
* engaging families in the process of treatment decision making.
* assessing parental knowledge and understanding of the medication regimen.
* addressing and modifying inaccurate beliefs concerning the safety and effectiveness of pain medications.
* simplifying the drug regimen to the degree possible.
Parents should be advised to fill prescriptions in advance of the scheduled surgery to ensure the availability of pain medication after discharge. In addition, many parents have identified the following tools as practical aids in implementing a successful pain management plan in the home:
* a digital timer to assist with the prescribed analgesic regimen56, 57
* a pain management diary to track analgesic dosing, the child's pain intensity scores, and other symptoms56
* use of an algorithm to assist in making decisions about analgesic administration58
Other strategies include using alcohol-free versions of prescribed analgesics to avoid irritating the injured throat, adding flavoring to medications, and refrigerating medications to make them easier to swallow; however, the effectiveness of these strategies has not been studied.
At many outpatient surgery centers, nurses follow up with patients by calling their home the day after surgery to ask about their progress and the effectiveness of pain medication, reinforce discharge instructions, and respond to parental concerns. Parents of children undergoing tonsillectomy consider these calls useful in providing emotional support and reassurance.56, 59, 60 In one investigation, nurse telephone follow-up improved home analgesic administration and fluid intake,60 in contrast to a previous study in which it had no effect on medication administration, although parents found it validated their decision making and promoted their use of a pain management diary.56
NONPHARMACOLOGIC PAIN MANAGEMENT STRATEGIES
Both parents and school-age children report eating cold foods (like ice cream) and drinking fluids as the nonpharmacologic strategies they most commonly use to manage pain following tonsillectomy.61-63 Other studies of postsurgical pain management have included such nonpharmacologic strategies as sleep or rest, distraction, and parents spending time with or holding their child.9, 62, 64, 65 A cold pack to relieve pain around the neck and jaw, a heating pad for ear pain, chewing gum to lessen pterygoid muscle spasm, and use of a humidifier to prevent the discomfort of desiccation have also been suggested but are not well supported by research.
Investigations into the effects of diet and activity restrictions on posttonsillectomy recovery have been inconsistent. Although a 1995 study showed that such restrictions had no effect on posttonsillectomy pain, vomiting, number of doses of acetaminophen administered, and postoperative bleeding,66 a 2010 study found that they had noticeable effects on postoperative pain (pain was lowest in the least-restricted group), as well as on bleeding and antibiotic use (both were most frequent in the least-restricted group).67 The extent to which nonpharmacologic comfort measures reduce the intensity of children's postoperative pain has not been evaluated, but the perceived benefit reported by children and parents suggests that they are helpful and should be incorporated into patient and family teaching.
REFERENCES