Perioperative Analgesia Using Gabapentin in Head and Neck Cancer Surgery

Patients undergoing head and neck cancer surgery frequently experience significant post surgical pain, which often necessitates the use of narcotic pain medication. However, opioids can have multiple side effects that can complicate the head and neck cancer surgery patients postoperative care including nausea, vomiting, dizziness, sedation, pruritis, urinary retention, delirium, constipation, and time to ambulation. This, in turn, may affect patient length and cost of hospital stay. Consequently, a multimodal approach to analgesia is often employed with a focus on use of scheduled acetaminophen +/- NSAIDs supplemented with narcotics.

The use of gabapentin in the head and neck surgery literature has largely been limited to outpatient surgeries, including tonsillectomy in children and adults, functional endoscopic sinus surgery, and thyroidectomy. Indeed, a recent systematic review examined RCT comparing multimodal analgesia with gabapentin to analgesia without gabapentin in the otolaryngology literature. The majority of these studies employed preoperative dosing only, with only 1 study providing a single postoperative dose as well. The control group pain regimen among these studies did vary and included a combination of acetaminophen, NSAIDs, dexmedetomidine, or clonidine supplemented with opioids. The studies focused on the impact of gabapentin on acute postoperative pain determined by subjective measurement of reduction in visual analog pain scale. Of note, these patients were not hospitalized for longer than 24 hours. The thyroid and sinus studies consistently demonstrated improved pain control with use of gabapentin compared to control. The data was slightly more variable across the tonsillectomy studies. Moreover, 7 studies also measured the need for breakthrough pain medication and supplemental analgesia; each of these studies demonstrated significantly less supplemental analgesia consumption in the gabapentin group.

The only study examining the utility of gabapentin in pain management in head and neck cancer patients (glossectomy with anterolateral thigh free flap) examined the utility of a single preoperative dose. The authors concluded that this led to a significant reduction in subjective postoperative pain scores, morphine requirement, and nausea and vomiting compared to controls. This study did not employ postoperative gabapentin.

Furthermore, a recent meta analysis (133 RCT) examining literature across multiple surgical specialties pertaining to the efficacy of perioperative gabapentin supplementation vs placebo. The meta analysis indicated both the efficacy of gabapentin supplementation in decreasing opioid requirement (measured via morphine equivalent units) in the experimental group during the first 24 hours (P<0.001), as well as a good safety profile across a wide range of loading and maintenance doses (200 to 1200 mg) of gabapentin. The significant reduction in opioid requirement was independent of surgery type. Moreover, the gabapentin group demonstrated a significant decrease in VAS postoperative pain scores, nausea, vomiting and itching; however, sedation scores were increased. Only 8 of these 133 RCT examined the effect of gabapentin outside the immediate 24 hour period, and all 8 trials demonstrated improvement in chronic pain scores at 3 months post-operatively. Finally, patient satisfaction scores and preoperative anxiety were also significantly improved with the use of gabapentin compared to controls.

Here, the investigators propose, for the first time, a superiority double blind randomized controlled placebo trial examining the effect of perioperative supplementation with gabapentin in head and neck cancer patients undergoing surgery. The primary purpose of this study is to determine the difference in morphine equivalent units between the experimental (i.e. perioperative gabapentin) and control group (i.e. no perioperative gabapentin). The secondary purpose of this study is to determine differences across the two groups in relation to the following: visual analog pain scores, cost and length of stay, medication side effects, and incidence of postoperative complications. Of note, in order to maximize reliability of the visual analog scale (VAS), prior studies have employed the Jadad scoring system, which the investigators will also implement in the study.