Influence of muscle-sparing lateral thoracotomy on postoperative pain and lameness: A randomized clinical trial.

Anna E Nutt,Darren Carwardine,Lee B Meakin,Toby G Knowles,Neil G Nutt,Guillaume Chanoit,Joanna C Murrell

doi:10.1111/vsu.13599

Abstract

To assess and compare the magnitude of lameness and level of pain after muscle-sparing lateral thoracotomy (MSLT) and standard lateral thoracotomy (SLT) in dogs. Randomized, blinded, prospective clinical study. Twenty-eight client-owned dogs. The latissimus dorsi muscle was retracted in the MSLT group and was transected in the SLT group. Gait was analyzed with a force plate, and the peak vertical force symmetry index (SI) was calculated within 24 hours before surgery, 3 days postoperatively, and 8 to 12 weeks postoperatively. Symmetry index and pain scores as measured by the Glasgow Composite Measure Pain Scale - Short Form were assessed as primary outcome measures. The SI 3 days postoperatively was lower compared with the preoperative SI value in all dogs, consistent with lameness of the ipsilateral thoracic limb (P < .001). The absolute differences in preoperative and 3-day-postoperative SI provided evidence that this change was 3.1-fold greater after SLT compared with after MSLT (P=.009). Pain scores 1 day after surgery were lower after MSLT (1) compared with after SLT (2.5, P < .001). Lateral thoracotomies caused postoperative pain and ipsilateral forelimb lameness, and both were reduced by sparing the latissimus dorsi. Sparing the latissimus dorsi should be considered to decrease immediate postoperative morbidity in dogs undergoing lateral thoracotomy.

Highlights

Results of this study were presented as a scientific abstract at the 28th ECVS Annual Scientific Meeting; July 4-6, 2019; Budapest; Hungary and at the 2019 ACVS Surgery Summit; October 16-19, 2019; Las Vegas, Nevada
The literature on the subject in animals is sparse; the authors of one study described the technique of muscle-sparing lateral thoracotomy (MSLT) in 20 dogs,[12] and those of a second study compared postoperative pain between the two techniques, concluding that muscle-sparing lateral thoracotomy was less painful than standard lateral thoracotomy (SLT).[13]
The hypothesis that MSLT would reduce immediate postoperative pain and lameness was confirmed on the basis of our results

Summary

Introduction

Results of this study were presented as a scientific abstract at the 28th ECVS Annual Scientific Meeting; July 4-6, 2019; Budapest; Hungary and at the 2019 ACVS Surgery Summit; October 16-19, 2019; Las Vegas, Nevada. Muscle-sparing lateral thoracotomy reduced pain scores by two and a half times the day after surgery, and there was a clear trend toward overall lower pain severity scores in this group as measured by the CBPI.

Results

Conclusion