Pain Control in Pediatric Posterior Spine Fusion Patients: The Effect of Gabapentin
Condition: Pain, Postoperative
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 4

Summary: 
      The purpose of this study is to evaluate the patient experience when using gabapentin with
      other pain control medications after posterior spinal fusion surgery for scoliosis in
      adolescents. These results will be compared to patients who underwent the same procedure
      during the study period and received the same standardized pain control regimen excluding
      gabapentin. Effects on pain level, opioid use, and satisfaction will be measured. Opioid side
      effects including nausea, sedation and urinary retention (inability to empty one's bladder)
      will also be recorded.The null hypotheses are as follows:

        1. There is no significant difference in pain control when adding gabapentin to a
           multimodal pain management protocol in pediatric post-operative posterior spinal fusion
           patients.

        2. There is no significant difference in the amount of opioid medication required for pain
           control in pediatric post-operative posterior spinal fusion patients.
    

Detailed description: 
      Patients aged 10-19 years with idiopathic scoliosis, and classified as American Society of
      Anesthesiology (ASA) class I to III who intended to undergo posterior spinal fusion for
      deformity correction were enrolled. Prior to surgery, subjects were randomized into either
      the experimental or control group by the OHSU research pharmacy using an online randomization
      tool, which utilized block randomization upon patient enrollment to result in equal sized
      groups at study completion. Patients, caretakers and providers remained blinded to the group
      assignments.

      Patients filled out the Scoliosis Research Society, SRS-22 standardized form at a
      pre-operative clinic appointment. Following hospital admission, patients recorded initial
      pain level with the Visual Analog Scale (VAS) prior to receiving standardized pre-operative
      medications. The VAS scale used in this study was a 10 cm line with anchors of "no pain" at
      the left and "worst pain imaginable" at the right; each point was measured to the nearest
      millimeter. In the post-operative period, nursing staff assessed patient pain using the VAS
      at 4-hour intervals from 06:00 until 22:00 for the duration of hospitalization for a minimum
      of 4 daily scores recorded per patient. After the third post-operative day, but before
      discharge, the parent or guardian of each subject was asked to complete an IRB-approved
      survey to measure parent demographics and parental satisfaction with the patient's
      hospitalization and pain control.

      Each patient received standardized medications according to our multimodal pain protocol.
      Following hospital admission, patients in both groups received one 12.5 mg/kg dose of
      intravenous (IV) acetaminophen. Patients in the experimental group received one 15 mg/kg dose
      of liquid gabapentin while the control group received a placebo, formulated to match the
      volume, color, taste, and smell of the experimental medication. The gabapentin or placebo was
      prepared by the OHSU research pharmacists so that providers and investigators remained
      blinded to treatment assignment. Several intraoperative anesthetic medications were given to
      subjects in both groups including: IV ketamine at 5mcg/kg/min for 120 minutes and IV
      Ketorolac 0.5mg/kg up to 15mg. Intra-operative IV propofol and IV hydromorphone were titrated
      to desired effect.In the post-operative period, gabapentin was administered to the
      experimental group at 10mg/kg PO q8h, beginning at Phase II and continued through
      postoperative day four. The control group received equivalent volume doses of placebo at the
      same intervals. Post-operative medication was administered according to the following
      protocol for both groups: ketorolac continued at 0.5mg/kg up to 15mg IV q6h for 12 total
      doses. Once ketorolac doses were complete, the patient may have received Ibuprofen 10mg/kg up
      to 600mg PO as needed. Hydromorphone was given through patient-controlled analgesia (PCA) at
      a basal dose of 0.002mg/kg/hr for 24 hours and demand dose of 0.004mg/kg with an 8-minute
      lockout. Once basal PCA was discontinued, administration of oxycodone 0.1-0.2mg/kg PO up to
      15mg PO q4h as needed supplemented the PCA demand dose. If the patient tolerated PO oxycodone
      without emesis, the PCA hydromorphone was discontinued after 24 hours, but a rescue dose of
      hydromorphone 0.002mg IV q4 was available if needed. Other as needed medications included
      diazepam 0.15mg/kg up to 5mg PO q6h for muscle spasms, ondansetron 0.1mg/kg up to 4mg IV q12h
      for nausea, and IV acetaminophen 12.5mg/kg up to 1000mg q6h. Acetaminophen 12.5mg/kg up to
      650mg PO q6h hours was administered after the IV was removed. All patients received one
      Senokot-S tablet and Miralax 0.8 g/kg up to 17g daily for bowel regimen.

      For the entire hospitalization, nursing staff monitored vital signs and assessed sedation
      using the standardized Pasero Opioid-induced Sedation Scale (POSS) protocols at 4-hour
      intervals.16 Any POSS score of 3 or greater resulted in more frequent monitoring of
      respiratory status and sedation level, decreased opioid dosing, and administration of
      naloxone as needed. All patients were routinely monitored for known adverse gabapentin drug
      reactions including: peripheral edema, nausea/emesis, viral disease, ataxia, dizziness,
      nystagmus, somnolence, hostile behavior, fatigue and fever, Stevens-Johnson syndrome, drug
      hypersensitivity reactions, drug induced coma/seizure, and suicidal thoughts. Any perceived
      adverse reaction would have resulted in the gabapentin or placebo being stopped at the
      clinicians' discretion
    

Intervention name(s): Gabapentin 250mg/5mL NDC:59762-5025-01; Simple Syrup
Intervention type(s): Drug; Drug
Intervention MeSH terms: Gabapentin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: gabapentin; Analgesic Drugs; Analgesics, Nonopioid