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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Elective Reconstructive Surgery, Pain, Post Operative

Intervention / Treatment
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* Procedure: femoral nerve block, common peroneal nerve block


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group PCA+B<br>Both intravenous PCA and lower limb blocks were used. For patients with fibular flaps harvested, femoral nerve block and common peroneal nerve block with ropivacaine were administered. For patients with ALT flaps harvested, femoral nerve block with ropivacaine was administered.The interventions are femoral nerve block, common peroneal nerve block. | Procedure: femoral nerve block, common peroneal nerve block<br>* 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.<br>* Other names: lower limb blocks with dexmedetomidine as additivewere;|
| No Intervention: Group PCA<br>Only intravenous patient controlled analgesia (PCA) was used postoperatively. | |
| Experimental: Group PCA+B+D<br>Both intravenous PCA and lower limb blocks with dexmedetomidine as additivewere used. | Procedure: femoral nerve block, common peroneal nerve block<br>* 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.<br>* Other names: lower limb blocks with dexmedetomidine as additivewere;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-operative Narcotic Usage | Total intravenous sulfentanyl usage for rescue analgesia in first 48 hours post-operatively after free fibular flaps and anterolateral thigh flap reconstruction. | 48 hours | 
| duration of sensory blockade | the time of sensory recovery | 48 hours | 
| duration of motor blockade | the time of motor recovery | 48 hours | 
| onset of sensory blockade | the time to sensory blockade | 48 hours | 
| onset of motor blockade | the time to motor blockade | 48 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-operative Anti-emetic Usage | Post-operative Anti-emetic Usage is defined as the total amount of IV tropisetron administered to a patient during the first 48 hours post-operatively. | 48 hours | 
| vital signs | hear rate, blood pressure, SPO2 | 48 hours | 
| Post-operative Pain Score | Post-operative Pain Score is defined using Visual Analog Scale (VAS), a patient reported pain score on a scale of 0-10. | 48 hours | 
| adverse effects | such as bradycardia, hypotension,respiratory depression, postoperative sedation | 48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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free flap, nerve block, elective reconstructive surgery, dexmedetomidine, anterolateral thigh flaps