Local Infusion of Ropivacaine for Post-Op Pain Control After Osseocutaneous Free Flaps

Role of Continuous Local Infusion of Ropivacaine for Post-Operative Pain Management in Patients Receiving Osseocutaneous Free Flaps

Head and neck oncologic surgery often requires the use of free tissue transfer, or microvascular reconstruction, to reconstruct defects created by tumor resections. Although there are several techniques for the reconstruction of defects, resection of large tumors leave defects that require the transfer of vascularized tissue from one part of the body to repair the defect. For example, the removal of a segment of diseased mandible requires free tissue transfer containing the component parts - skin, muscle, and bone - to reconstruct the deficit created by the resection of the tumor. Over the years, microvascular surgeons have focused their attention on maximizing the success of these technically difficult surgeries. However, now, with free flap reconstruction rates in excess of 95%, surgeons are afforded the opportunity to turn their focus toward the morbidities associated with these surgeries. While much has been published about donor site wound healing, pain control in the post-operative period has largely been neglected in the head and neck reconstruction literature. Systemic analgesia with opioids is standard of care, which has been shown to lead to increased confusion, significantly increased length of stay and increased risk of pulmonary complications. In addition, it has been shown that early mobilization and optimal wound care can decrease donor site morbidity.

In this study the clinical team aims to better control donor site pain utilizing local, targeted analgesia to relieve pain at the donor site for osseocutaneous free-flaps. To reduce confounding and bias, the study will be a double-blind prospective randomized placebo controlled trial wherein patients undergoing osseocutaneous free flap surgery will be randomized to receive continuous infusion of ropivacaine or normal saline (placebo) via local continuous infusion catheter, which will be placed intraoperatively at the time of donor site closure. Patients' pain will be monitored for the first 48hrs after surgery. Donor site and global pain at rest will be evaluated every 8 hours for the first two postoperative days using a visual analogue pain scale (VAS). Essentially, there is a 100 millimeter line drawn on a piece of paper, with "no pain" marking the left end of the line and "worst pain" marking the right end of the line. Subjects mark with a pen along the line where pain is felt fits along that continuum. A researcher then measures how far along the line that mark is placed and then it is recorded. Median daily opiate use via PCA will also be tracked. Donor site-specific range of motion and strength will be assessed with a formal physical therapy evaluation on post-operative day 2 or soonest non-holiday weekday. Information on patient satisfaction, time to ambulation, and length of stay will also be collected. Subgroup analysis will be performed.

Procedures involved in this study include:

- Intraoperatively, following procurement of the fibula or scapula bone graft and at the time of surgical wound closure, all patients will receive the placement of a continuous infusion catheter into the donor site wound bed. The infusion reservoir will be connected to a catheter-based On-Q pump, and the catheter will be placed in the donor site. A stab incision separate from the surgical wound will be used to bring the catheter through the skin. Patients will be randomized to receive 6 ml/hr of 0.2% Ropivacaine or 6 ml/hr of normal saline via the infusion reservoir. The catheter will be left in place with continuous infusion for first 48 hours of the post-operative period. The catheters will be removed by the housestaff on POD2. There is minimal risk to removing the OnQ catheter. Any opening in the skin will be covered with gauze to allow primary healing. Solutions of saline and ropivacaine will be prepared and made available for infusion by the Mount Sinai Pharmacy. Solutions will be blinded, and identical in appearance. Patients will be assigned to ropivacaine or saline intervention by the research pharmacy through coded envelopes. Patients, physicians, nurses, and research personnel will be blinded to treatment assignment. Every 8 hours for the first 48 hours, patients will be asked to complete a visual analogue scale (VAS) for reporting their pain. The VAS will be performed six times over the course of the 48hrs. These will be performed during regular flap check monitoring, to ensure patients are not disrupted additional times throughout the day for this study. Patients will otherwise receive standard of care pain management, including Tylenol 650 q6hr standing as well as a dilaudid PCA set to low-dose, opioid naïve. On post-operative day 2 patient will receive a physical therapy evaluation.

Prior to discharge from the hospital, the study subjects will be asked to complete a brief survey (APS-POQ-R Pain Survey) regarding their experience, with regard to pain management.

Inclusion Criteria:

• Patients receiving osseocutaneous free tissue transfer regardless of the indication for free tissue transfer.

This includes osseocutaneous tissue from fibula and scapula

• Age ≥ 18

Exclusion Criteria:

• Patients unable to understand the research protocol and/or provide informed consent
• Patients under the age of 18
• Patients with a history of allergic reaction to Ropivacaine or other local amide anesthetics
• Patients whose participation in this trial would require exclusion from participation in another clinical research trial related to the patient's malignant diagnosis.
• Patients with previous pain disorders or drug abuse requiring chronic narcotic use.
• Vulnerable populations (adults unable to consent, individuals who are not yet adults, wards of the state, prisoners)