Intrathecal baclofen for postoperative analgesia after total knee arthroplasty.
OBJECTIVE
To determine whether intrathecal baclofen is an effective adjunctive agent to decrease acute and chronic postoperative pain after total knee arthroplasty.


METHODS
Prospective, randomized, double-blind controlled trial.


METHODS
Operating room and inpatient units of a university hospital.


METHODS
60 adult, ASA physical status I, II, and III patients presenting for total knee arthroplasty.


METHODS
Anesthesia was provided by spinal injection of 15 mg of 0.75% hyperbaric bupivacaine combined with either 100 mcg baclofen or saline. Sedation was provided with intravenous midazolam and propofol.


METHODS
Data were collected on adverse effects, opioid usage, and verbal pain scale (VPS) from 0 to 10. The study period was divided into six discrete time intervals that included the 1(st) 72-hour postoperative period and a three-month post-discharge follow-up telephone call.


RESULTS
The baclofen group used less morphine in the PACU than the control group (5 mg vs. 9.3 mg; P = 0.04). VPS were lower in the baclofen group than the treatment group, but significant differences could be demonstrated only in the time periods 48-72 hours and three months postoperatively. At three months, fewer patients in the baclofen group reported pain than the control group (8/27 vs. 19/29; P = 0.009). Regression analysis showed that the baclofen group was 4.5 times less likely to report pain at three months (95% CI: 1.5-16.6).


CONCLUSIONS
IT baclofen used as an adjuvant to spinal anesthesia for total knee arthroplasty allows for less postoperative opioid usage and less chronic pain at three months.
Sanders
John C
JC
Department of Anesthesiology and Critical Care, University of New Mexico - School of Medicine, Albuquerque, NM, USA. jcsanders@shrinenet.org
Gerstein
Neal
N
Torgeson
Eli
E
Abram
Stephen
S
D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local; D019645:Arthroplasty, Replacement, Knee; D001418:Baclofen / Q000008:administration & dosage / Q000627:therapeutic use*; D002045:Bupivacaine; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D018755:GABA Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy* / Q000453:epidemiology; D011229:Preanesthetic Medication; D011446:Prospective Studies
D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D018755:GABA Agonists; D009020:Morphine; D001418:Baclofen; D002045:Bupivacaine