Anaesthesia for shock wave therapy in musculoskeletal disorders: a preliminary report

The potential for using external applied energy to rectify or ameliorate musculoskeletal disorders has been explored for decades. A shock wave is a pressure disturbance: tissue effect is cavitation, producing microtrauma or microfracture and haematoma formation, inducing, as to date is thought, increase in vascularization, increased soft callus and faster enchondral ossification. Anaesthesiological interest in this field is focused in non-union or delayed osseous union, joint stiffness or osteochondrosis and femoral head necrosis in adults. Actually, because of the pain associated with high energy extracorporeal shock wave therapy on bones, anaesthesia is necessary, but, since almost all patients have no complaint after treatment, there is no need of postoperative analgesia. Therefore, short duration anaesthetic techniques and agents should be preferred. Loco-regional anaesthesia or general anaesthesia are both suitable to the purpose. Fifty patients have been treated nowadays in our Institution with shock wave therapy needing anaesthesia. 18 patients (36%) received general anaesthesia. Since patient's stay in hospital was expected to be short, short duration agents have been used, avoiding those causing unpleasent side effects, first emesis. We used Propofol or Remifentanil by continuous infusion, titrated to maintain stable haemodynamics and an appropriate level of anaesthesia. The short duration of action of Propofol depends on its rapid elimination, whereas Remifentanil undergoes rapid biotransformation to minimally active metabolites. 32 patients (64%) received regional anaesthesia. We avoided long acting agents or high concentration drugs. Spinal blocks have been performed with 0.5% hyperbaric bupivacaine; brachial plexus blocks, sciatic-femoral blocks and an epidural block have been performed with 0.5-1% xylocaine or 1% mepivacaine. Shock Wave Therapy has been done during a 3-day hospital stay. With suitable anaesthesiological treatment and preparation, almost all patients could be treated as outpatients or with an overnight hospital stay.