Pain Relief Following Arthroscopic Rotator Cuff Repair: Perioperative Pregabalin Administration Versus Interscalene Brachial Plexus Block. a Prospective, Randomized, Double Blinded, Multicenter Trial

Arthroscopic rotator cuff (RC) repair is often associated with severe post operative pain and discomfort. Many analgesic protocols have been proposed for pain relief following RC repair and controversy remains regarding the optimal postoperative analgesic protocol. Despite significant advancement in analgesic techniques over the last decades 50-70% of patients who undergo surgical procedures still experience moderate to severe postoperative pain. Postoperative pain has both inflammatory component (i.e. related to traumatic tissue damage and inflammatory reaction due to the surgical incision and procedure) and neuropathic component (i.e. related to over sensitization of the peripheral and central nervous system). Opioids are commonly used for postoperative pain reduction, however their use is associated with numerous adverse events and should be limited.

Regional nerve block techniques have been emerged over the past decade and have become a standard of practice recently. Recent studies indicate that a single-dose interscalene brachial plexus block (ISBPB) is effective in providing postoperative analgesia following shoulder surgery, reduces the need for opioid medication, and has a very high success rates (≥94%) and few major complications (≤0.4%). However, regional nerve blockade, including ISBPS, has a frequent incidence of temporary postoperative neurological symptoms within the first postoperative week (4 -16%), is technically demanding and might be time consuming.

Pregabalin (Lyrica) is an anticonvulsant drug with membrane stabilizing and anti-nociceptive effects commonly used for neuropathic pain relief and anxiety disorder. It desensitizes the presynaptic terminals of hyperexcited neurons in peripheral and central nervous system (i.e. reduces the transmission of excitatory neurotransmitters including glutamate, norepinephrine, substance P, and calcitonin gene-related peptide) by reducing calcium influx through high-voltage-activated calcium channels containing the alpha2/delta subunit. Pregabalin is rapidly absorbed from the gut with bioavailability of approximately 90%, achieves peak plasma concentration approximately 1h after administration, has half-life of about 6h and is eliminated by renal excretion. Many studies over the past decade have evaluated pregabalin roll in the treatment of acute postoperative pain. Pregabalin effect in reducing opioid consumption and opioid adverse events (AEs) has been well established. Its analgesic effect on acute postoperative pain remains questionable, and further studies are still required to compare pregabalin analgesic potential with other standard post-operative analgesic regimens. Pregabalin doses used in previous studies ranged from 75 to 600 mg given as a single dose 1-2h preoperatively with or without additional doses at 12h and 24h postoperatively. Doses of 150 mg and higher seemed to offer better results in terms of postoperative analgesia and opioids sparing. However higher doses were associated with higher rate of AEs, mainly sedation, dizziness and visual disturbances.

Nervous system desensitization by oral medication (e.g. pregabalin) rather than by invasive means (e.g. ISBPB) may reduce adverse reactions, increase patient satisfaction and save valuable time in the operation theater. To the investigators knowledge no previous study has compared the efficacy of pregabalin to ISBPB for acute pain relief following arthroscopic shoulder surgery. The investigators hope to contribute to the discussion regarding the optimal pain relief method following arthroscopic shoulder surgery.