Pain management in the care of otolaryngology patients: an anesthesiologist and pain physician's perspective

Acknowledgment

We would like to express our appreciation to Dr. Roger Goucke for the invaluable input, suggestion, and language editing of the manuscript.

Introduction

Pain has recently been redefined as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.” Pain is not only an undesirable experience, but also is associated with many consequences, including lower patient satisfaction, delayed recovery from surgery, and increased perioperative mortality and morbidity. Moreover, a prolonged period of pain can lead to long-term detrimental effects on quality of life, psychological and social function, and the economy.

Even though pain can cause the aforementioned consequences, improper pain management can lead to even more harmful complications such as an overdose or death from opioids as evidenced by the opioid crisis in some countries. ^, Pain is the most common reason that patients seek medical care, and the surgeon will encounter various types, both in the outpatient and inpatient setting. Thus, a fundamental understanding of pain management is an essential part of education for all surgeons, including otolaryngologists.

This chapter will describe the pain conditions that can be commonly found in the otolaryngologist's practice from acute perioperative pain, chronic noncancer pain, and chronic cancer pain.

Acute perioperative pain in otolaryngology

In the United States, more than 50 million inpatient operations are performed annually; however, less than half of these patients report adequate postoperative pain relief.

Inadequate pain control causes physiological changes in multiple systems and can lead to delayed recovery, morbidity, and mortality as follows:

Cardiovascular system: increased sympathetic output, increased blood pressure, heart rate and myocardial oxygen demand, and cardiac arrhythmias
Respiratory system: increased risk for atelectasis, pneumonia, and respiratory failure secondary to splinting
Gastrointestinal system: increased postoperative ileus
Nervous system: increased risk of postoperative delirium, increased risk of chronic postsurgical pain
Endocrine system: increased cortisol levels, elevated blood glucose, sodium and water retention, and protein catabolism
Immune system: immunosuppression and increased risk of postoperative infection, increased potential for cancer recurrence
Hematological system: increased risk for deep vein thrombosis due to immobilization

Magnitude of pain in otolaryngology surgery

Otolaryngology surgery can be associated with a variable degree of postoperative pain. A study showed groups of patients who underwent otolaryngology surgery have a 48%–58% incidence of moderate-to-severe pain after surgery in the oral region, pharynx, larynx, neck, and salivary glands, 4–10 times higher than when compared to ear surgery. Moreover, contrary to the general understanding that endoscopic procedures are quite painless, they have been associated with a 30%–35% incidence of moderate to severe pain on postoperative day zero.

The type of surgery is not the only predicting factor for the degree of acute postoperative pain. Besides the operative site, preoperative pain and pain catastrophizing (an exaggerated negative mental set brought to bear during an actual or anticipated painful experience) are independent risk factors of moderate-to-severe pain after surgery.

Management of perioperative pain

Pain assessment and measurement

The first step of successful pain management is the recognition and assessment of pain (RAT model; recognition, assess, and treat). The recognition starts from understanding the high incidence of pain and asking or noticing if the patient has pain, especially during the perioperative period (recognition). Recording pain intensity as “the fifth vital sign”—originally intended to improve recognition and acute pain management—contributed to unrealistic goals, such as being pain-free and excessive opioid use leading to overdoses, deaths from opioids, and the opioid crisis in North America. In 2018, the USA Joint Commission on Accreditation of Healthcare Organizations (JCAHO) implemented new and revised pain assessment and management standards, by focusing more on the impact of pain on patients' physical function, rather than pain intensity.

Pain assessment should be obtained from a thorough medical history and physical examination, pain history, functional impact, and adverse effects of treatment. Pain history can be obtained by the acronym PAIN: place (site of pain), amplitude (intensity), intensifier, and nullifier. At the end of taking the history, physicians should have a clear understanding of the type of pain, pain intensity, and individual physical and psychological factors contributing to the pain to determine a treatment plan.

Types of pain

There are many ways to classify pain (acute/chronic, cancer/noncancer, nociceptive/neuropathic). However, classifying by pathophysiology into nociceptive and neuropathic will help the clinician choose from the correct group of medications for treatment. The differences between nociceptive and neuropathic pain are shown in Table 2.1 .

Table 2.1

The differences between nociceptive and neuropathic pain.

	Nociceptive pain	Neuropathic pain
Definition	Pain that arises from nonneural tissue and is due to the activation of nociceptors	Pain caused by a lesion or disease of the somatosensory nervous system
Example	Acute: fracture, incisional pain Chronic: bone metastasis	Acute: nerve injuries, stump pain Chronic: chronic postsurgical pain
Characteristic	Dull aching pain	Sharp shooting pain Numbness, hyperalgesia, allodynia
Treatment	Acetaminophen Nonsteroidal anti-inflammatory drugs (NSAIDs) Opioids	Gabapentinoids Tricyclic antidepressants Serotonin and norepinephrine reuptake inhibitors (SNRIs) Opioids

Contrary to a general understanding that nociceptive pain is the exclusive type of pain in acute postoperative pain, acute postoperative pain can be a mixed component of nociceptive and neuropathic pain. Additionally, the concept of mixed pain has been studied in many chronic pain conditions, which were previously recognized as purely nociceptive pain. The prevalence of neuropathic pain in chronic low back pain is 20%–55% and 19%–39% in cancer pain.

As acute postoperative pain is mixed pain by nature, neuropathic pain medications such as gabapentinoids also have roles in acute postoperative pain. However, the high dose of gabapentinoids can be associated with sedation, and specific studies of gabapentinoids for otolaryngologic surgery are still limited. Finally, because opioids can alleviate both acute nociceptive and neuropathic pain, opioids have been popular analgesics in the acute pain setting (but not recommended as the first line for chronic noncancer pain).

Pain intensity

The pain intensity or severity will determine the strength of treatment, according to the analgesic ladder. Many pain measurement tools have been applied in clinical practice. However, self-reporting tools such as the Visual Analog Scale or Verbal Numerical Rating Scale (0–10 or 0–100) are the gold standard measurement of pain intensity and are most commonly used. Typically, the pain scale from 0 to 10 is classified into mild (0–3), moderate (4–6), or severe (7–10) pain.

There is little evidence that one pain assessment tool is superior to others. However, for certain patient populations where self-report is difficult or impossible, adapted scales or behavioral tools may be used instead. Examples of pain measurement tools for these specific populations include

Face, Legs, Activity, Cry, Consolability Scale for children ages between 1 and 6 years old (However, Face Pain Scale, which provides images from smiling to crying faces for the children to choose, is a self-reporting tool and is suitable for children ages more than 6 years old.)
Critical Care Pain Observation Tool for critically ill patients who are incapable of reporting their pain
Pain Assessment in Advanced Dementia Scale for cognitively impaired patient

Factors contributing to pain management

There are a number of factors that have been shown to have significant effects on pain management. These include

Physical factors such as allergies and comorbidities, especially any conditions that might affect pharmacological choice, such as a history of gastrointestinal (GI) bleeding, history of cardiovascular disease, kidney and liver function
Psychological factors such as depression, anxiety, and catastrophizing

Treatment of acute postoperative pain

The options for pain treatment include both nonpharmacological and pharmacological treatment.

Nonpharmacological treatment

Nonpharmacologic treatment can commence preoperatively with good education about the surgery and continue postoperatively with good communication and reassurance. There are many additional techniques to attenuate pain, such as distraction for children, application of cold, transcutaneous electrical nerve stimulation (TENS), relaxation therapy, music therapy, meditation, and acupuncture.

Pharmacological treatment

The World Health Organization's (WHO's) analgesic ladder originally intended to provide a stepped approach to the management of cancer pain ( Fig. 2.1A ); however, clinicians also apply it for acute pain. The model starts with nonopioids (acetaminophen, NSAIDs) for mild pain, then escalates to weak opioids (codeine, tramadol) for moderate pain, and strong opioids (morphine, fentanyl) for severe pain. Remembering that it is appropriate to start at the top of the ladder for acute severe nociceptive pain. As postoperative pain is usually acute and severe and tends to improve over time, the reverse ladder approach, which starts with strong opioids and steps down subsequently, has been applied for acute pain ( Fig. 2.1B ).

Figure 2.1, (A) The analgesic ladder for cancer pain, (B) The reverse analgesic ladder for acute pain. 10

Nonopioid analgesics

Nonopioid analgesics including nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, ketamine, local anesthetics (systemic, local infiltration, and regional block), clonidine, and gabapentin. Commonly used nonopioid analgesics, mechanism of action, route, and precaution are listed in Table 2.2 . The combination of two or more medications or techniques (such as combination with local anesthetic infiltration or regional anesthesia) that act by different mechanisms for providing analgesia is termed multimodal analgesia.

Table 2.2

Commonly used nonopioid analgesics, mechanism of action, and precaution.

Adapted with permission from Nantthasorn Z. Acute pain: Operative and postoperative pain, trauma, obstetric pain. In: Hogans B, Barreveld A, eds. Pain Care Essentials , Oxford University Press:2020.

Agents	Mechanism of actions	Route	Precautions	Side effects
Acetaminophen	Unknown, may involve cyclooxygenase, endocannabinoid, TRPV1, and serotonin	PO, PR, IV	Liver failure	Minimal, unless overdose (recommended dose less than 3–4 g/day)
Traditional NSAIDs (e.g., ibuprofen, naproxen, ketorolac)	Central and peripheral COX inhibitors	PO, IV	Allergy to NSAIDs. Decrease dose in renal impairment, elderly or bodyweight <50 kg	GI bleeding, renal failure and surgical bleeding, possible risk of anastomotic leakage after colorectal surgery
COX-2 inhibitors (e.g., celecoxib)	COX-2 inhibitors	PO	Cross allergy with sulfonamides	Fewer GI side effects. Minimal effect on platelets. Similar renal risk but increased cardiovascular events with long-term use
Local anesthetics	Sodium channel blockers	IV (lidocaine), local infiltration nerve block	Allergy to local anesthetic	Local anesthetic systemic toxicity
Ketamine	NMDA receptor antagonist	IV, IM, PO	Patient with psychosis	Hallucination, delirium, hypertension, tachycardia
Gabapentin, Pregabalin	Calcium channel blockers	PO	Adjust dose for renal function (CrCl <60 mL/min), elderly	Somnolence, dizziness

COX , cyclooxygenase; CrCl , creatinine clearance; GI , gastrointestinal; IM , intramuscular; IV , intravenous; NMDA , N-methyl-D-aspartate; NSAIDs , nonsteroidal anti-inflammatory drugs; PO , per os; PR , per rectum; TRPV1 , transient receptor potential cation channel subfamily V member 1.

Multimodal analgesia improves pain control, reduces opioid requirements, reduces opioid-related side effects, and has the potential to reduce costs in patients undergoing surgery. Strong evidence shows that NSAIDs, gabapentin, pregabalin, systemic lidocaine, and ketamine are opioid-sparing medications and reduce opioid-related adverse effects.

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