Trial of Injected Liposomal Bupivacaine vs Bupivacaine Infusion After Surgical Stabilization of Rib Fractures

Study Overview
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Brief Summary
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Rib fractures represent a common injury pattern this is highly associated with patient morbidity and mortality, as pain control remains a challenge. Even after surgical stabilization of rib fractures (SSRF), unsuccessful pain control can lead to morbid outcomes such as pneumonia and opioid dependence. Multi-modal anesthesia, with the use of thoracic epidurals and para-vertebral injections/catheters, has shown to lessen these occurrences but are subject to a wide array of limitations. A more directed therapy with liposomal bupivacaine has shown to provide sustained analgesia for up to 72 hours in patients who have undergone other types of thoracic surgery, but not SSRF. The hypothesis of the current clinical trial is that, among patients undergoing SSRF, liposomal bupivacaine delivered via video assisted thoracic surgery (VATS) is an intercostal nerve block that provides comparable analgesia to the pain catheter, as measured by pulmonary function, numeric pain scoring, and postoperative narcotic use.

Detailed Description
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Rib fractures represent a common injury pattern with high associated morbidity and mortality. Effective pain control in both the acute and long term periods remains a challenge. Surgical stabilization of rib fractures (SSRF) is now a recommended treatment for patients with severe chest wall injuries. In addition to stabilization of the chest wall, SSRF offers a unique opportunity to deliver directed, loco-regional anesthesia. Loco-regional anesthesia is a recognized, essential component of multi-modal anesthesia for patients with rib fractures in order to both decrease pain and minimize the use of opioids and their associated side effects. Delivery options for loco-regional anesthesia to patients with rib fractures share in common the intention of anesthetizing the intercostal nerves. Moving from the spinal cord laterally, modalities include thoracic epidural catheters, paravertebral blocks or catheters, and rib/intercostal blocks. Although rib blocks may be accomplished via a variety of techniques, the two most common intra-operative techniques are video-assisted thoracoscopic surgery (VATS) intercostal nerve blocks and indwelling, subscapular catheters In general, neuraxial modalities such as thoracic epidural and para-vertebral injections/catheters are subject to a wide array of limitations, including patient coagulopathy (International Normalized Ratio > 1.5), co-existing spine fractures, peri-insertion, peri-removal withholding of venous thromboembolism pharmacoprophylaxis, and provider availability. For these reasons, our current practice is to insert a subscapular pain catheter at the conclusion of the SSRF operation; this catheter is able to deliver a continuous infusion of 0.25% bupivacaine and may be left in place for several days. Although favorable results using the pain catheter have been published in patients with rib fractures who have not undergone SSRF, we have noticed several limitations to this treatment modality. First, position is highly variable; and, because the catheter is not truly in the space of the intercostal nerves, drug delivery is likely irregular. This variability may be particularly relevant in obese patients; and the median body mass index of patient who underwent SSRF at Denver Health is 29 kg/m^2. Beyond catheter placement, we have also experienced issues with leakage of drug from the skin entry site of the catheter. Moreover, catheters frequently become dislodged or inadvertently removed during patient transport. Further, the indwelling foreign body likely introduces some risk of infection. Finally, the presence of the catheter is distressing to many patients. Liposomal bupivacaine (Exparel, Pacira Pharmaceuticals, Inc., Parsippany, NJ, www.pacira.com) has been shown to provide sustained analgesia for up to 72 hours following a single injection of the drug delivery system. The safety and efficacy of liposomal bupivacaine has been evaluated in over 1,300 subjects and 21 clinical trials. Although many of these trials have included thoracic surgery patients, no trial has evaluated the efficacy and safety of liposomal bupivacaine administered to patients with rib fractures undergoing SSRF. Potential benefits as compared to current practice include directed injection immediately adjacent to the intercostal nerve using a VATS approach, as well as obviation of the need for an indwelling catheter. The hypothesis of the current clinical trial is that, among patients undergoing SSRF, liposomal bupivacaine delivered via video assisted thoracic surgery (VATS) is an intercostal nerve block that provides comparable analgesia to the pain catheter, as measured by pulmonary function, numeric pain scoring, and postoperative narcotic use.

Official Title
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A Randomized Clinical Trial of Single Dose Liposomal Bupivacaine Delivered Via VATS Intercostal Nerve Block vs. Continuous Bupivacaine Infusion Delivered Via Indwelling Subscapular Catheter After Surgical Stabilization of Rib Fractures

Conditions
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Drug Effect, Rib Fractures, Rib Trauma, Surgical Procedure, Unspecified, Pain; Catheter (Other), Nerve Pain, Local Infiltration, Anesthesia, Local, Intercostal Rib, Opioid Dependence, Chest Injury Trauma, Pneumonia

Intervention / Treatment
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* Drug: Liposomal bupivacaine injection
* Drug: Bupivacaine indwelling catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing SSRF at Denver Health Medical Center Exclusion Criteria: Allergy or hypersensitivity to bupivacaine Pregnancy Incarceration Age < 18 years Indwelling continuous thoracic epidural analgesia

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Non-inferiority, randomized, clinical trial
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Bupivacaine indwelling catheter<br>Bupivacaine indwelling OnQ pain pump catheter will be placed in the subscapular space at the time of surgery, at infusion of 12 ml/hr of 0.25% bupivacaine, and left in place for a maximum of 120 hours | Drug: Bupivacaine indwelling catheter<br>* Bupivacaine indwelling OnQ pain pump catheter is placed in the subscapular space at the time of SSRF for continuous bupivacaine infusion post op<br>* Other names: OnQ pain pump, Continuous infusion of bupivacaine;|
| Active Comparator: Liposomal bupivacaine injection<br>A single injection of liposomal bupivacaine: mixture of 20 mL liposomal bupivacaine, 20 mL 0.25% bupivacaine, and 10 mL sterile saline (50 mL total), will be delivered in the intercostal space during VATS (with a 178 mm, 22 gauge needle, at ribs 3-8). | Drug: Liposomal bupivacaine injection<br>* A single injection of liposomal bupivacaine is administered at the time of SSRF, directly to the fracture site via VATS<br>* Other names: Exparel;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Daily Sequential Clinical Assessment of Respiratory Function (SCARF) Score | The SCARF score is a validated, dynamic tool that ranges from 0-4, with 0 being the best score and 4 being the worst. One point is given for each of the following four parameters: (1) respiratory rate ≥ 20 breaths per minute; (2) numeric pain score ≥ 5; (3) incentive spirometry < 50% of predicted based upon a nomogram including sex, height, and age; (4) cough deemed inadequate to clear respiratory secretions by respiratory therapists. The parameters used to calculate the SCARF score are summed to create the total 0-4 score and these results were recorded by clinical personnel not involved in the trial. SCARF scores were taken at 10 am daily for all postoperative inpatient hospital days, however due to variance in length of stay, only scores from the first 5 postoperative days were recorded for the purpose of this results analysis. Scores were then aggregated across the patients and timeframe to result in one median score per group. | Median SCARF scores were recorded for the first 5 postoperative days. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Daily Narcotic Requirements Using Equi-analgesic Doses | Narcotic pain medication requirements were recorded daily over the duration of inpatient hospital stay, however due to variance in length of stay, only the first 5 postoperative days were recorded for this analysis. Scores were averaged across patients providing one daily postoperative mean score per treatment group. The narcotics provided to patients varied based on standard of care, so an Equi-Analgesic Scale was used to standardize dosages across narcotic type. A 1:1 ratio for narcotic dosages is calculated with the following measured as equivalent: 1.5 milligrams (mg) of intravenous (IV) Hydromorphone; 7.5 mg of per oral (PO) Hydromorphone; 100 micrograms (mcg) of IV Fentanyl; 10 mg of IV Morphine; 30 mg of PO Morphine; 20 mg of PO Oxycodone (Percocet); and 30 mg of PO Hydrocodone (Vicodin). In the context of this scale, lower scores are best, indicating fewer narcotics required and higher scores are worse indicating the need for more narcotics based on subjective patient pain. | Mean narcotic requirement scores were recorded for the first 5 postoperative hospital inpatient days. | 
| Percentage of Participants Experiencing Failure of Primary Loco-Regional Analgesia (LRA) | The failure of LRA for this study was defined as the percentage number of instances a patient required a secondary LRA modality within 72 hours of placement of the primary modality for either treatment arm. Requirement of this secondary LRA was determined by the patients' medical team with criteria based on subjective patient experience of pain. | 72 hours |