Published 7/1/2015
Terry Stanton

Study Probes Use of Pain Medication by AIS Patients After Surgery

Pain tolerance and postoperative use of opiates varies among adolescents undergoing PSF

Adolescents undergoing posterior spinal fusion (PSF) for idiopathic scoliosis who require more pain medication than average following surgery are more likely to be heavier and male, according to study data presented by Daniel R. Grant, MD, at the Pediatric Orthopaedic Society of North America annual meeting. The study also found that patients who self-reported having a “high tolerance” for pain used more medication than those with “average tolerance.”

Opioid abuse and the role of prescribers in the opioid epidemic are commonly addressed in the context of adults and adolescents who take narcotic drugs and fall into addiction. Various measures have been taken to rein in prescription of opioids and to contain their distribution, including reclassification by the U.S. Food and Drug Administration of certain pain medications into a more restrictive category. However, as the study authors pointed out, “surgeons have been shown to prescribe more narcotic pain medication than patients routinely need after surgery.”

Study methods
The study, performed at Nemours/AI duPont Hospital for Children, involved 41 patients (37 of whom completed surveys), with a mean age of 15 years, who underwent PSF for adolescent idiopathic scoliosis (AIS).

The patients were given a single preoperative survey (Scoliosis Research Society-22) within a few weeks of surgery, which included questions about demographics, preoperative pain, postoperative expectations, and self-reported pain tolerance. On the day of surgery, all patients underwent PSF with a standard technique and were provided with a multimodal pain protocol as follows: morphine patient-controlled analgesia (PCA) with a basal dose, gabapentin, and 24-hour transdermal clonidine immediately postoperatively.

On postoperative day 1, the basal dose was discontinued; the PCA remained for demand dosing; up to three doses of ketorolac were administered; and patients were started on oral oxycodone-acetaminophen.

On day 2, patients were fully transitioned off the PCA to oral oxycodone-acetaminophen, the dosing of which was adjusted as needed based on level of pain, opioid sensitivity, and patient weight. Patients were typically discharged to home on postoperative day 3 or 4 with a prescription for oxyco-done-acetaminophen. Follow-up was arranged 4 weeks later.

Patient-reported data
After discharge, patients received once-a-week electronic surveys for 4 weeks, allowing for prospective self-reporting of the pain level, number of pills taken in the previous week, and need for any medication refills. Two investigators reviewed the medical record and entered surgical details, immediate postoperative pain scores, complications, and prescription and refill data into a database. The senior surgeons completed an immediate postoperative survey for each patient to identify any potential factors the surgeons thought might result in increased postoperative narcotic requirements.

Of the 37 patients completing surveys, 25 (68 percent) were female. The surveys revealed that patients reported less actual pain than predicted each week. The average total narcotic use was 51 pills. Those who required more medication were more likely to be male.

The authors reported that preoperative assessment of pain tolerance by the patient was unreliable, because “high-tolerance” patients used more medication than those with “average tolerance” (by patient self-reporting, 58 pills versus 41 pills; P < 0.05).

Another finding was that most patients (75 percent) planned to dispose of the medications in some way; the remainder planned on keeping them for potential future use.

The study found that patients underwent a steady decline of pain over the first 4 weeks following surgery. The average postoperative pain score was nearly the same at week 4 postoperatively as it was preoperatively. Although pain scores tapered off gradually, pain medication usage dropped precipitously. Slightly more than half of the medication taken was in the first week and about a third in the second week. Significantly less was taken in week 3 and “hardly any” was taken in week 4.

The authors found no clear reason that patients who preoperatively assessed themselves as having a high pain tolerance required more medication, but they did note that “perception of pain is a complex psychological process” and may be “very dependent on culture.”

Beyond the pain score
“Patients’ perceived self-efficacy significantly affects their pain perception and medication use,” wrote the authors. “Psychological findings that increased anxiety leads to slower improvements in pain scores and leaves open to question the reliability of pain scores. More factors than simply a pain score need to be evaluated when treating patients. Additional research and emphasis need to be placed on these alternative factors of pain.”

Among the limitations of the study, the authors noted, was that it relied on self-reporting the number of pills patients had remaining, which could be a source of potential error and observation bias. Also, they wrote, generalizability of the pill numbers to other medications is limited.

The authors concluded that postoperative narcotic dosing may be improved by considering patient sex and the inverse of self-assessed pain tolerance. “These are some easily evaluated factors, which will hopefully allow practitioners to adjust prescriptions for patients, allowing for more accurate doses prescribed,” the authors wrote.

“My experience prior to this study was that patients who say they have a high pain tolerance anecdotally needed a lot of pain medication,” said Dr. Grant, now at West Virginia University. “I expected that this was largely due to my own recall bias, so when we did the study I wasn’t expecting to see an actual difference. Upon doing the surveys, the patients were very sincere and at times convincing when they said they had a high pain tolerance. The results indicated, though, that those individuals required more medications.

“Pain is a complex entity. All patients do not have the same narcotic requirements,” he concluded. “Those who are male and who classify themselves as having a ‘high pain tolerance’ use more pain medication than other individuals. Also, even with reasonable prescribing practices, significant amounts of narcotic medications will remain unused. Surgeons should discuss disposal of these medications with patients.

Dr. Grant’s coauthors of “Are We Giving Our Patients Too Much Pain Medication?” are: Scott J. Schoenleber, MD; Alicia M. McCarthy, CPNP-AC; Geraldine I. Neiss, PhD; Petya K. Yorgova, MS; Kenneth J. Rogers, PhD; Peter G. Gabos, MD; and Suken A. Shah, MD.

Details of the authors’ disclosures may be accessed at www.aaos.org/disclosure

Terry Stanton is a senior science writer for AAOS Now. He can be reached at tstanton@aaos.org

Bottom Line

  • Some research has shown that surgeons prescribe more pain medication after surgery than is necessary.
  • This study examined pain medication use by adolescent patients who underwent posterior spinal fusion surgery for idiopathic scoliosis.
  • Patients who took more pain medication than average were likely to be male and to report a high tolerance for pain.
  • One quarter of patients planned to keep medications for potential future use; patients should be counseled about proper disposal of leftover drugs.