The Efficacy and Safety of Lower Limb Nerve Blocks in Postoperative Analgesia for the Free Flap Donor Sites

The use of free fibular flaps and anterolateral thigh (ALT) flaps for repairing the oromandibular defects is well established, whereas few attentions were focused on postoperative analgesia for the donor area. Dexmedetomidine is a more selective and shorter-acting α2 adrenergic receptor. The purpose of this trial is to determine if using lower limb nerve blocks in patients undergoing free flap-based oromandibular reconstruction can significantly decrease use of pain medications and to evaluate the safety of lower limb nerve blocks. We also investigated the effect of adding dexmedetomidine as additive in femoral nerve blocks for postoperative analgesia.

Patients with oromandibular defects who were scheduled for elective reconstructive surgery using free fibular or ALT flaps, were divided into three groups in a randomized, single-blind fashion. In Group PCA, only intravenous patient controlled analgesia (PCA) was used postoperatively. In Group PCA+B, both intravenous PCA and lower limb blocks were used. In Group PCA+B+D, both intravenous PCA and lower limb blocks with dexmedetomidine as additivewere used. Post-operative narcotic usage, post-operative pain score, post-operative anti-emetic usage, vital signs, onset and duration of sensory and motor block, the presence of adverse effects such as nausea and vomiting were recorded.

The use of free fibular flaps and anterolateral thigh (ALT) flaps for repairing the oromandibular defects is well established, whereas few attentions were focused on postoperative analgesia for the donor area. Conventional postoperative pain management following oromandibular reconstruction consists of systemic opioids, which can cause nausea, vomiting, pruritus, urinary retention, constipation and respiratory depression. Adequate postoperative analgesia decreases the incidence of cardiopulmonary complications. Peripheral nerve blocks can attenuate the sensory innervations.The purpose of this trial is to determine if using lower limb nerve blocks in patients undergoing free flap-based oromandibular reconstruction can significantly decrease use of pain medications and to evaluate the safety of lower limb nerve blocks.

Patients with oromandibular defects, who were scheduled for elective reconstructive surgery using free fibular or ALT flaps, were divided into three groups in a randomized, single-blind fashion. In Group PCA, only intravenous patient controlled analgesia (PCA) was used postoperatively. In Group PCA+B, both intravenous PCA and lower limb blocks were used.In Group PCA+B+D, both intravenous PCA and lower limb blocks with dexmedetomidine as additivewere used. For patients with fibular flaps harvested, femoral nerve block and common peroneal nerve with ropivacaine were administered. For patients with ALT flaps harvested, femoral nerve block with ropivacaine was administered. Post-operative narcotic usage, post-operative pain score, post-operative anti-emetic usage, vital signs, onset and duration of sensory and motor block, the presence of adverse effects such as nausea and vomiting were recorded.

Eligibility Criteria:
Inclusion Criteria:

* Prior diagnosis or presumed diagnosis of oral and maxillofacial tumor.
* Undergoing microsurgical oromandibular reconstruction with free fibular flaps and anterolateral thigh flaps.
* Greater than 18 years old.
* Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

* True allergy to local anesthetics or opioids.
* History of addiction to narcotics within the last 24 months
* History of chronic pain on opioids within the last 24 months.
* Specific mental health issues such as schizophrenia or bipolar disorder.
* Patients who are pregnant.