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Perioperative pain management in rhinology and anterior skull base surgery
Introduction
The nasal cavity exists to warm, humidify, and sample air for olfaction as we inspire. The role of the paranasal sinuses is not as clear, though it is hypothesized that they exist, at least in part, to lighten the skull and provide a source of protection for the intracranial and orbital contents as a sort of “crash zone” in the case of head trauma. While these roles are important, many pathologies can also manifest within the nose and paranasal sinuses.
Many pathologies involving the nose and paranasal sinuses can be managed with minimally invasive surgery—termed endoscopic sinus or endoscopic skull base surgery ( Table 3.1 ). One of the most common pathologies within the paranasal sinuses is chronic rhinosinusitis, which is the presence of objective sinus inflammation for >12 weeks with associated symptoms such as mucopurulent drainage, nasal obstruction, and facial pain or pressure. Other common surgically managed pathologies include nasal airway obstruction and benign and malignant neoplasms. Many intracranial pathologies can involve the anterior and medial skull base, which can be managed through extended endoscopic endonasal approaches rather than external craniotomies.
Table 3.1
Examples of pathologies managed with endoscopic sinus or skull base surgery.
| Anatomic abnormalities |
|
| Inflammatory/infectious |
|
| Benign sinonasal neoplasms |
|
| Malignancy sinonasal neoplasms |
|
| Intracranial/skull base pathology |
|
Surgical injuries, whether external or endoscopic, initiate an acute inflammatory reaction that manifests as pain. Postoperative pain is expected after most surgical procedures, and it is essential that surgeons understand and prepare patients for the pain that they will experience. Some people even go as far as to say that one of the primary goals of surgery is the appropriate management of the resultant pain.
Although endoscopic sinus and skull base surgeries are minimally invasive, it would be expected that they induce postoperative pain. Inadequate postoperative pain management adversely affects both the patient and the healthcare industry. Uncontrolled pain can result in surgical complications such as atelectasis from poor pulmonary toilet, thromboembolism from immobilization, and cardiovascular morbidity due to catecholamine release. These complications ultimately delay the patient's return to normal functional status. , Studies have also demonstrated that inadequate pain management after surgery results in decreased patient quality of life, decreased satisfaction, increased hospital readmission rates, increased length of hospital stay, and increased healthcare costs. ,
A commonly cited source of surgical hesitation is the fear of severe or uncontrolled pain. In the realm of the opioid crisis, many patients are also concerned about opioid addiction and fear the use of opioids after surgery. By having a better understanding of the expected postoperative pain, surgeons can improve patient counseling, allowing patients to mentally prepare for their recovery and potentially improving postoperative outcomes.
Endoscopic sinus surgery
Pain after endoscopic sinus surgery
Endoscopic sinus surgery (ESS) is utilized to manage pathologies of the nose and paranasal sinuses. Currently, ESS is one of the most commonly performed procedures in the United States, with greater than 250,000 performed annually. Despite the prevalence of ESS, to date, there are no specialty-specific guidelines for the management of pain after surgery. Of those performed, approximately 3.7% result in readmission for pain. While 3.7% is low overall, this corresponds to nearly 10,000 patients per year who are readmitted for poorly controlled pain after ESS. There are also likely many more patients whose pain is poorly controlled but do not require readmission.
To appropriately counsel patients on pain expectations after ESS, it is important to first understand the painfulness of ESS. Many studies have been performed evaluating the severity of ESS-induced pain, all with similar results: ESS is not associated with severe pain. Utilizing a visual analog scale of 0–10, with 10 being the most severe pain, most studies have demonstrated that the peak of pain after ESS is approximately 2–4 on postoperative day 1 and rapidly declines over the course of the first week. , One study of 64 patients found that only nine patients (14.1%) reported pain greater than five out of 10 within the first week of ESS.
Many attempts have been made to identify features associated with increased pain after ESS. There is a general consensus that the severity of sinus disease, the presence or absence of nasal polyps, use of nasal packing, and extent of surgery do not significantly impact postoperative pain. , There are conflicting data regarding the impact of septoplasty on postoperative pain, with some studies demonstrating that the inclusion of a septoplasty at the time of ESS may increase pain, while other studies have not found a correlation. , , Although evaluations of pain after nonrhinologic surgery have demonstrated an impact of age, gender, and mental illness of postoperative pain, unpublished data from our group show that only the presence of anxiety adversely impacted the severity of postoperative pain (Smith Unpublished Data).
As a first step in mitigating pain after ESS, surgeons should counsel patients on the expectation of mild to moderately severe pain. Surgeons should also evaluate their patients preoperatively for anxiety and ensure that any comorbid anxiety is appropriately managed. Often patients with anxiety also require additional counseling regarding expectations of pain after surgery. By optimizing the surgeon–patient relationship and providing more extensive counseling preoperatively, patients may have more realistic expectations for pain after ESS, resulting in improved outcomes.
Preemptive pain control
Acute tissue injury modulates the central nervous system, ultimately sensitizing patients to pain. Preemptive pain control, the application of regional or systemic medications before the initial surgical injury, diminishes the central nervous system response, ultimately mitigating the severity of perceived postoperative pain. For ESS, many options have been proposed for preemptive pain control ( Table 3.2 ).
Table 3.2
Preemptive pain control options.
| Drug | Dose/concentration | Risks |
|---|---|---|
| Acetaminophen | 1000 mg PO | Nausea Headache Hepatotoxicity |
| Anticonvulsants | ||
| Gabapentin Pregabalin |
600–1200 mg PO 75–300 mg PO |
Increased intraoperative bleeding Drowsiness Dizziness Nausea Anxiety Confusion Dry mouth |
| Glucocorticoids | ||
| Dexamethasone | 8–10 mg IV | Hyperglycemia Impaired wound healing |
| Alpha agonists | ||
| Dexmedetomidine
Clonidine |
1 μg/kg IV bolus, 0.2 μg/kg/h infusion 2–5 μg/kg IV bolus, 0.3 μg/kg infusion |
Sedation Dry mouth Nausea Vomiting Bradycardia Hypotension Loss of smell |
| Locoregional anesthetics | ||
| Lidocaine Bupivacaine Levobupivacaine |
1%–2% submucosal injection 0.25%–0.5% submucosal injection 0.5% submucosal injection |
Dizziness Headache Blurred vision Twitching muscles Prolonged numbness |
Acetaminophen
Acetaminophen is a common, inexpensive analgesic. The exact mechanism of acetaminophen is unknown, though it is believed to work via the inhibition of cyclo-oxygenase (COX) enzymes with simultaneous modulation of the serotonergic and cannabinoid pathways. Overall, acetaminophen is well tolerated, though it has a known risk of hepatotoxicity, especially in those with a history of liver dysfunction.
Acetaminophen has been utilized for preemptive analgesia in nonrhinologic surgery, but there has only been limited research evaluating the role of preemptive acetaminophen for the prevention of ESS-induced pain. One study of otolaryngologic surgeries not limited to sinus surgery showed that the preoperative administration of acetaminophen resulted in a trend toward decreased pain after surgery, though the impact was not significant. Bjoja et al. evaluated the impact of a preoperative dose of 1000 mg oral acetaminophen administered preoperatively against 1000 mg of intravenous acetaminophen administered at the end of ESS and found no significant difference in postoperative pain, indicating that a single preemptive oral dose is likely equivalent to a postoperative intravenous dose.
Although the data are limited for ESS, acetaminophen has a long history of use in conjunction with surgery and is overall safe and well tolerated. Oral acetaminophen is significantly less expensive than parenteral acetaminophen, indicating that it is likely preferable to give a preoperative oral dose than to give an intravenous dose at the time of surgery. In patients in whom there is no contraindication, a preemptive dose of acetaminophen has little risk and the potential of significant benefit.
Gabapentinoids
The gabapentinoids gabapentin and its lipophilic analog pregabalin interact with neuron voltage-gated calcium channels, decreasing calcium influx and reducing neurotransmitter release. They were first introduced as antiepileptic drugs but have also been found to have antihyperalgesic and antiallodynic properties via the reduction of neuron hyperexcitability in injured tissue. The analgesic properties of gabapentinoids were first noted for neuropathic pain conditions such as diabetic neuropathy and postherpetic neuralgia. However, as gabapentinoids decrease neuronal excitability, there has been increased interest in their utilization for the prevention of central nervous system sensitization and postoperative pain.
Many studies outside of otolaryngology have evaluated the utility of a preemptive dose of gabapentin and pregabalin and have demonstrated their utility. One systematic review of 28 studies found that a preoperative dose of gabapentin significantly reduced postoperative analgesic requirements and pain for nonrhinologic surgeries. While those studies are promising, there is one potential drawback of preemptive gabapentinoids that may limit their utility for preemptive analgesia—gabapentinoids are known to inhibit platelet aggregation via the phospholipase C-inositol 1,4,5-triphosphate thromboxane A(2)-Ca(2+) pathway. Platelet inhibition could potentially increase bleeding during surgery. Although the studies for nonrhinologic surgery do not note significant changes in operative bleeding, small changes in hemostasis can significantly impact ESS. As ESS is reliant upon endoscopic visualization, poor hemostasis intraoperatively can result in limited visibility and thus increase the risk of complications and increase operative times.
To date, very few studies have evaluated the impact of preoperative gabapentinoids on postoperative pain and analgesic use for ESS. In a recent meta-analysis of sinus and nasal surgery, only three studies that evaluated the impact after ESS were identified. Those studies evaluated a range of preoperative gabapentin (600–1200 mg) and found that preemptive gabapentin significantly decreased analgesic requirements postoperative as well as lengthened the time until the first analgesic was required after ESS. Interestingly, despite the known side effects of nausea and vomiting, those that received gabapentin preoperatively had less postoperative nausea and vomiting. Although the data were limited, on meta-analysis, subjects in the ESS subgroup were noted to have increased operative blood loss after gabapentinoid administration than the septoplasty subgroup, but operative field visibility was not found to be significantly impaired.
Currently, there are no studies that have evaluated the use of pregabalin before ESS. However, pregabalin has been utilized before open septoplasty with promising results. Doses ranging from 75 to 300 mg have been administered, all of which significantly decreased pain within the first 24 h of surgery. Higher doses of pregabalin yielded more profound reductions in pain without apparent increases in adverse effects.
Preoperative gabapentinoids have promising results for the mitigation of postoperative pain. However, their utility for pain management may be limited by the potential impact on intraoperative hemostasis. Additional studies will need to be performed to determine the overall impact of preoperative gabapentinoids on ESS. If intraoperative hemostasis and visibility are not adversely impacted, the gabapentinoids may serve as a viable adjunct for preemptive analgesia.
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