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October 03, 2020
10/3/2020 1:00:00 PM - 10/3/2020 2:00:00 PM
Room Virtual
Association Between Intraoperative Use Of Muscle Relaxant And Postoperative Pain And Muscle Spasm After Spine Surgery
Jagan Devarajan, M.D., Shobana Rajan, M.D., Sonal Patel, M.D., Chen Liang, M.S., Kamal Maheshwari, M.D., Rafi Avitsian, M.D., Andrea M. Kurz, M.D.
Cleveland Clinic, Cleveland, Ohio, United States
Disclosures: J. Devarajan: None. S. Rajan: None. S. Patel: None. C. Liang: None. K. Maheshwari: None. R. Avitsian: None. A.M. Kurz: None.
Spinal procedures are associated with intense postoperative pain amnd muscle spasm. Muscle spasm is often caused by tissue injury from excessive stress or strain on muscles by intsrumentation and cutting. For example, during surgical procedures on the spine, retractors are placed to stretch the muscles for better surgical exposure. The force placed on the muscle would be higher if the muscle is not adequately paralyzed, causing micro injury to muscle fibers. This increased force and microinjru to muscles can hypothetically worsen pain perceived as spasm. Adequate muscle relaxation during a spine procedure may help decrease the force and consequently postoperative painful spasms. The same phenomenon has been shown in gastrointestinal laparoscopic surgeries. Hence we sought to find whether adequate intraoperative muscle relaxation decreased postoperative pain scores, muscle spasms and opioid consumption. Methods: It was a retrospective study. Patients who had spine surgery between 2012 and 2018 were included. Patients with use of muscle relaxants per kg body weight per hour within the upper 50 percentile of the observed values were classified as having adequate muscle relaxant, while patients with use of muscle relaxants within the lower 25 percentile of the observed values were classified as low muscle relaxation groups. We claimed one group to have more effective pain control if it performed noninferior on both pain score and opioid consumption and superior on at least one of the two. We also compared the two groups on postoperative nausea and vomiting, use of Diazepam and PACU length of stay. Potential confounding factors were adjusted for in all analysis using inverse probability of treatment weighting. Results: 1219 patients had adequate muscle relaxant group and 581 belonged to low muscle relaxant group. The group with adequate muscle relaxant did not have a higher postoperative pain score, with a difference in pain score of 0.03 (97.5% CI: (-0.17, 0.22), P = 0.75). However, adequate muscle relaxant group have 1.30 (97.5% CI: (1.08, 1.57), P = 0.001) times higher opioid consumption. The group with low muscle relaxation performed noninferior on pain score (Noninferiority P < 0.001) and superior on opioid consumption (Noninferiority P < 0.001), and we would claim the group with inadequate muscle relaxant to have had better post operative analgesia. The group with adequate muscle relaxant had less postoperative nausea and vomiting : 0.48 (0.23 0.998), (OR (98.3 CI) P = 0.017), but more use of Diazepam 1.35 (1.15, 1.59), P <0.0001). PACU length of stay was not different between the two groups, with ratio of geometric means estimated at 1.06 (98.3 CI: (0.98, 1.06), P = 0.08)Conclusion: Patients who had adequate muscle relaxants required more narcotics and more smooth muscle relaxants in the post operative period. ReferencesNielsen R V, et al.The effect of chlorzoxazone on acute pain after spine surgery. A randomized, blinded trial. Acta Anaesthesiol Scand. 2016;60(8):1152-1160.2. Gornitzky AL, et al. A Rapid Recovery Pathway for Adolescent Idiopathic Scoliosis That Improves Pain Control and Reduces Time to Inpatient Recovery After Posterior Spinal Fusion. Spine Deform. 2016;4(4):288-292

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