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.

Inclusion Criteria:

- Patients undergoing head and neck cancer ablation with concomitant free flap
reconstruction surgery at UCDMC. There will be two groups. Group 1 will include
reconstruction with fibula free flap only. Group 2 will include any other free flap
reconstruction, including scapular free flap, radial forearm free flap, anterolateral
thigh free flap, anteromedial thigh free flap, and latissimus dorsi free flap.

- Patients naïve to gabapentin

- Adult patients >18 years of age and able to consent

Exclusion Criteria:

- Patients who are already taking scheduled gabapentin

- Patients allergic to gabapentin

- Chronic opioid use not from active head and neck cancer

- Illicit drug use (per report)

- Patients with known renal compromise, such that Creatinine clearance is < 30

- Patient with known hepatic insufficiency or cirrhosis

- Adults unable to consent

- Individuals less than 18 years old

- Pregnant women

- Prisoners