The aim of the study is to assess the effects of a continuous popliteal block on postoperative pain and recovery after major ear, nose and throat surgery with microvascular free flap reconstruction using a fibula graft.

Tumors of the head and neck is one of the most common cancer types, and the incidence is increasing. Management of these tumors is complex, and treatment can include surgery with extensive resection of the mandible or maxilla, which requires reconstruction using a microvascular free flap, oftentimes a part of the fibula. The injury to the operated leg can cause significant postoperative pain, which in these patients traditionally has been treated with intravenous opioids. These drugs have good analgesic properties, but also several side effects, such as fatigue, nausea and respiratory depression. The experience at Skåne University hospital in Lund has also been that the analgesic effect in the leg has been insufficient. The investigators would therefore like to evaluate the effect of adding a continuous popliteal block on postoperative pain and opioid consumption, as well as postoperative recovery. This type of block is regularly used for orthopedic surgery of the fibula, but its effects and significance have not been evaluated for the patient group in question.

Patients will receive information about the study and, if they opt to participate, be included during the routine preoperative visit. All patients included in the study will preoperatively receive a popliteal nerve block catheter in technical accordance with local procedure guidelines, and be randomized to either active substance (local anesthetic) or placebo (saline solution). They will receive a bolus injection of the allotted substance (blinded to both patient, care provider and investigator) at the start of surgery, followed by continuous infusion during the first, maximally, seven days. During this period pain, nausea and vomiting, as well as sensory and motor function in the operated leg will be recorded regularly. Opioid consumption, need for other analgesics and ability to mobilize will also be noted. Follow up of above mentioned parameters will be made at the first routine office visit at three months postoperatively.

Inclusion Criteria:

• Patients at Skåne University hospital department of ear, nose and throat surgery undergoing major resection of maxilla or mandible and reconstruction using free fibula graft.
• Preoperatively able to walk (with or without aid).

Exclusion Criteria:

• Neurological disease or peripheral neuropathy affecting the donor leg of the fibula graft.
• Conditions of coagulopathy, or treatment with anticoagulant drugs, that contraindicates peripheral nerve block according to local guidelines.
• Local anesthetic allergy.
• Inability to understand study information or answer questions.