Peri-operative Botulinum Neurotoxin injection to improve outcomes of surgeries on spastic limbs: A systematic review

Our objective was to systematically review literature regarding the rationale and current evidence for peri-operative Botulinum Neurotoxin (BoNT) injection to improve outcomes of surgeries on spastic limbs. We conducted a systematic search of databases MEDLINE, EMBASE, and Cochrane Central Register of Controlled until March 2020, using the PRISMA guidelines. After assessing all titles and abstracts against inclusion criteria, full texts were reviewed for studies of potential interest. The inclusion criteria were studies on humans with any study design, published in all languages. Participants had to have underlying limb spasticity and be scheduled to undergo surgery on one or more spastic limb(s). BoNT had to be administered peri-operatively to improve surgical outcomes and not solely for the purpose of alleviating spasticity. The risk of bias was evaluated using the Physiotherapy Evidence Database (PEDro) scoring system for randomized controlled trials (RCTs) and the Downs and Black tool for RCTs and non-randomized trials. Further, the level of evidence was evaluated using a five-level scale (simplified form of Sackett). Five studies met our inclusion criteria comprising a total of 90 participants, of both pediatric and adult age groups, with underlying limb spasticity, who received BoNT perioperatively to improve outcomes of the surgeries performed on spastic limbs. Interventions were intramuscular BoNT injection prior to, at the time of, or after surgery on a spastic limb for the purpose of improving surgical outcomes, and not solely for alleviating muscle spasticity. Outcome measures were surgical success/failure, post-operative pain and analgesic use, sleep quality, adverse events, spasticity control e.g. Modified Ashworth Scale. Our literature search yielded 5 articles that met the inclusion criteria. Current evidence supports peri-operative injection of BoNT to improve outcomes of surgeries performed on spastic limbs. There is level 1 evidence that BoNT administered pre-operatively is effective for reducing pain, spasticity, and analgesic use in pediatric patients with cerebral palsy (CP). This is supported by level 4 evidence from a retrospective case series. Level 5 evidence from case reports highlights the potential for the use of BONT in the peri-operative period. There is level 1 evidence that BoNT administered intra-operatively is not effective for reducing pain and analgesic use in pediatric patients with CP. This lack of benefit may reflect sub-optimal timing of injections, different methods of injection, different timing of the primary outcome measure, and/or differences in adjunctive therapies, but further research is required.