Effects of immediate post-operative pain medication on length of hospital stay: does it make a difference?

Patient reported outcomes and length of hospital stay (LOS) are being used as a proxy for hospital care. An extra day of hospitalization costs thousands of health care dollars. The choice of intraoperative pain medications has been associated with decreased pain scores in other surgical subspecialties. However, the effects of immediate post-operative patient-controlled analgesics (PCA)/intravenous (IV) pain medication on patient care are not well understood in spine surgery. The aim of this study is to determine the effects of different immediate post-operative pain medications on post-operative complications profile, LOS, and patient reported outcomes (PROs) after elective spine surgery.

The medical records of 230 patients (morphine: n=98, fentanyl: n=61, hydromorphone: n=71) undergoing elective spine surgery at a major academic medical center were reviewed. Patients were categorized by the immediate post-operative pain medication they were on, with the most common medications being PCA/IV morphine, fentanyl, and hydromorphone. Patient demographics, comorbidities, and post-operative complication rates were collected. All patients had retrospectively collected outcomes measures and a minimum of 6-month follow up. Patient reported outcomes instruments [Oswestry Disability Index (ODI), SF-36 and Neck/Back/Leg-Pain Visual Analog Scale (VAS-NP/BP/LP)] were completed before surgery, then at 3- and 6-month after surgery.

Baseline characteristics were similar in all cohorts. Operative variables were also similar in all cohorts, with no difference in operative time, estimated blood loss (EBL), or fusion levels. Complication rates were similar between cohorts, with the fentanyl-cohort having an increased percentage of urinary tract infection (UTI) than the morphine and hydromorphone cohorts (16.39% vs. 5.15% vs. 5.63%, P=0.0277). The morphine-cohort had a decreased LOS than the fentanyl and hydromorphone cohorts (4.18 vs. 5.56 vs. 5.69 days, P=0.0376). There was a significant difference in the number of feet first ambulated by the patient post-operatively for the morphine and hydromorphone cohorts than the fentanyl-cohort (morphine: 118.44±18.15 vs. fentanyl: 59.26±20.78 vs. hydromorphone: 125.91±19.85, P=0.0420). There was no significant differences in 30-day hospital readmission rates between the cohorts, morphine-cohort did trend lower than the other cohorts (morphine: 5.10 vs. fentanyl: 11.48 vs. hydromorphone: 11.27, P=0.2492). There were no significant differences in PROs between the two cohorts in ODI, SF-36, and VAS-NP/BP/LP at baseline, 3- and 6-month.

Our study demonstrates that the choice of immediate post-operative pain medication can make a difference in the hospital course for patients. Identifying these types of factors might help increase patient care and reduce health care costs.