Erector Spinae Plane Block for Video-assisted Thoracoscopic Surgery

Study Overview
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Brief Summary
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Video-Assisted Thoracoscopic Surgery (VATS) is a minimally invasive surgery that utilizes camera based scopes and specialized instruments through keyhole sized ports to remove lesions in the thoracic cavity. Despite reduced surgical trauma compared to the traditional thoracotomy approach, patients continued to experience moderate to severe postoperative pain. Pain medication such as opioids is commonly utilized for postoperative pain control but is associated with side effects. The use of nerve blocks, such as the recently described erector spinae plane block (ESPB) has been shown in case reports to reduce pain and thus has the potential to improve patient recovery and decrease the risk of pulmonary complication. This study aims to investigate the analgesic effect of ESPB in managing pain following VATS.

Detailed Description
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VATS is a minimally invasive surgical technique to remove intrathoracic lesions. Using a camera based scope and specifically designed instruments, the surgery can be initiated with three key-hole sized incisions. At the end of the surgery, an incision is enlarged to allow removal of surgical specimen. Chest tubes are inserted at the end of procedure and sutured in between the ribs. While acute pain after VATS is less than the traditional thoracotomy, patients still experience moderate amount of pain within the first 24 hours. Source of pain may be from diaphragm irritation, surgical incisions and chest tubes. Because of its origin on the chest wall, pain from VATS worsens with breathing. When pain is poorly controlled, it will lead to a shallow breathing pattern called splinting and this can progress to respiratory distress or failure. Given the high incidence of smoking history in this patient population, many would have presented with poor baseline respiratory function. Therefore, it is important to provide good pain control to allow deep breathing and cough to reduce respiratory complications[1][2]. Despite the smaller incisions, the incidence of chronic post-surgical pain (CPSP) after VATS is surprisingly similar to thoracotomy. The mechanism may be due to nerve compression by the trocar, an instrument inserted between the ribs to allow smooth manipulation of camera and surgical instruments in the thoracic cavity. Additionally, poorly controlled acute pain has also been postulated to lead to the development of CPSP, further emphasizing the importance of good analgesia[1]. Many regional analgesia techniques have been tried to improve postoperative analgesia. Thoracic epidural analgesia (TEA) remains the gold standard of pain control after thoracic surgery. Although it provides superior analgesia, its use is hindered by the rare but serious complication of epidural hematoma and abscess which may cause paralysis. Further, pain from VATS tends to be short-lived (less than 24 hours), making the risk to benefit ratio less ideal for TEA. An alternative to TEA is paravertebral block (PVB). Compared to TEA, it causes less hypotension and hematoma or abscess at the paravertebral space may be less consequential. Nevertheless, PVB is a deep block and is technically demanding which limits its wide adoption[3]. Erector spinae plane block (ESPB) is a novel nerve block that has been used for analgesia for surgeries of the chest and abdominal wall. Using a bony structure, the transverse process, as the end point, the block needle is very unlikely to cause injury to vital structures as is possible with TEA or PVB (for examples, the spinal cord, lungs and blood vessels). It is also technically easy to perform. ESPB has only been reported in case series but so far, no adverse events such as hypotension, hematoma or infection has been reported. ESPB has also showed promise in managing CPSP after thoracic surgery in a small case series[4]. Given its safety, ease of performance and efficacy, the study aims to study the analgesic efficacy of ESPB in addition to systemic analgesia compared to systemic analgesia alone in patients undergoing VATS. The hypothesis is that ESPB and systemic analgesia will provide better analgesia when compared to systemic analgesia alone.

Official Title
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Erector Spinae Plane Block for Video-assisted Thoracoscopic Surgery: a Randomized Controlled Trial

Conditions
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Thoracic Surgery, Peripheral Nerve Block, Analgesia

Intervention / Treatment
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* Drug: Ropivacaine Injection [Naropin]
* Drug: Normal saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients Scheduled for an elective VATS American Society of Anesthesiologists (ASA) physical status I to III Exclusion Criteria: Age < 18 BMI > 40 Patient refusal or inability to provide consent Chronic pain conditions Daily opioid use > 60 mg of oral morphine equivalents Cognitive or psychiatric condition that makes it challenge to assess pain Conversion to open thoracotomy Allergy to any of the drugs used in this study Contraindication to nerve blocks such as infection, severe coagulopathy or pre-existing neuropathy Significant systemic cardiac, respiratory, hepatic or renal diseases Postoperative admission to intensive care unit

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: The study will be a single center (Victoria Hospital), prospective randomized, patient and assessor blinded randomized controlled trial.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham Block<br>Patient will receive a single shot of normal saline 20 mL injected at the erector spinae plane | Drug: Normal saline<br>* Normal saline will be injected in the erector spinae plane<br>* Other names: Sham block;|
| Active Comparator: Erector Spinae Block<br>Patient will receive a single shot of Ropivacaine Injection [Naropin] 0.5% 20 mL injected at the erector spinae plane | Drug: Ropivacaine Injection [Naropin]<br>* Ropivacaine will be injected in the erector spinae plane<br>* Other names: Erector spinae block;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Opioid consumption in IV morphine equivalents | All source of opioid | First postoperative 24 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Opioid consumption in IV morphine equivalents | All source of opioid | Second postoperative 24 hours | 
| Area under curve of pain score | 0 - 10 numeric rating scale for pain (0 minimal pain and 10 worst pain ever) | First postoperative 24 hour | 
| Area under curve of pain score | 0 - 10 numeric rating scale for pain (0 minimal pain and 10 worst pain ever) | Second postoperative 24 hour | 
| Post-anesthetic recovery length of stay | In minutes | up to 12 hours | 
| Hospital length of stay | in hours | Up to 1 week | 
| Incidence of nausea | patient reported sensation of nausea related to opioid intake | Up to 1 week | 
| Incidence of vomiting | nurse recorded incidence of vomiting related to opioid intake | Up to 1 week | 
| Incidence of drowsiness | lightheadedness, drowsiness reported by patient related to opioid intake | Up to 1 week | 
| Incidence of pruritus | new onset of pruritus related to opioid intake | Up to 1 week | 
| Incidence of infection at block injection site | defined as redness, swelling, tenderness and/or prurulent discharge | Up to 1 week | 
| Incidence of symptomatic hematoma at block injection site | collection of blood confirmed by ultrasound | Up to 1 week | 
| Incidence of paresthesia in the area covered by block | paresthesia, decreased sensation thought to related to block | Up to 1 week | 
| Incidence of hypoxia | hypoxia (SaO2 < 90%) despite > 5 L oxygen | during the first 24 hours | 
| Incidence of mechanical ventilation | requiring re-intubation | during the first 24 hours | 
| Incidence of tachypnea | Respiratory rate more than 30 for more than 2 hours | during the first 24 hours |