Postoperative analgesia after orthopaedic limb surgery : are peripheral nerve blocks efficient techniques?

Effective control of postoperative pain remains one of the most important and pressing issues in the field of surgery. The key to improve postoperative pain management is to individualise the analgesic treatment for each patient. The routine quantification of postoperative pain is absolutely vital and must be addressed first. The staff nurse, as the healthcare provider with the greatest degree of patient interaction, is the most suitable to regularly assess pain, evaluate the effectiveness of pain management, and identify the side effects and drug interactions. Providing him/her with an easy and reliable pain scoring is essential. The introduction of balanced analgesia, pre-emptive analgesia, and new techniques for the delivery of analgesic drugs, such as intravenous patient-controlled analgesia (PCA) and epidural analgesia has improved the management of acute pain. Pain after orthopaedic limb surgery is among the most severe encountered by the clinician. Moderate to severe at rest, it is exacerbated on movement and by severe reflex muscle spasm. It hinders early intense physical therapy, the most influential factor for good postoperative rehabilitation. The traditional technique of intramuscular administration of a fixed dose of opioid given on an as-needed basis is particularly inefficient in such surgery due to frequent undermedication and inefficacy on pain on movement. General principles (systematic pain scoring, balanced analgesia, pre-emptive analgesia) and new techniques (IV PCA or Patient-controlled epidural analgesia (PCAE)) of postoperative analgesia undoubtedly improved pain relief after orthopaedic limb surgery. However, IV PCA provides inadequate analgesia on movement and is associated with a high incidence of side effects such as sedation, nausea-vomiting, and urinary retention. Continuous epidural analgesia is more effective in relieving pain on movement that IV PCA, but the benefit in consistency and quality of pain control is offset by side effects, such as urinary retention and arterial hypotension. Moreover, because of the risk of causing an epidural hematoma, the concurrent use of low molecular weight heparin (administered in most orthopaedic patients as prevention of deep venous thrombosis) and epidural anaesthesia remains controversial. That’s why, in orthopaedic limb surgery, surgical teams are still in search of alternative postoperative analgesic techniques with improved efficacy: side effects ratio. In this thesis, we demonstrated that, after ambulatory orthopaedic limb surgery, “refined” (use of a peripheral nerve stimulator, short catheter technique, new landmarks, …) peripheral nerve (axillary, brachial plexus, popliteal sciatic nerve) blocks and the addition of small doses of clonidine (≤ 0.5 µg/kg) to the local anaesthetic solution provide reliable surgical anaesthesia and improved postoperative analgesia. After major orthopaedic limb surgery, continuous peripheral nerve (interscalene or axillary brachial plexus, “3-in-1”, poplietal sciatic nerve) blocks provide better postoperative analgesia than parenteral (IM or IV) opioids. They are as efficient as epidural analgesia, but induce much less side effects. Thus, they should be considered as the best available techniques to provide postoperative analgesia after orthopaedic limb surgery. The quality of analgesia they provide requires increased vigilance to identify postoperative surgical complications otherwise heralded by acute pain (compartment syndrome, tight cast, malpositioning, …). Close medical attention and frequent systematic searching of nervous or vascular complications remain essential parts of any safe postoperative analgesia policy. An efficient team approach (nurse-surgeon-anaesthetist) of each patient is thus of paramount importanceThèse de doctorat en sciences biomédicales -- UCL, 199