Thoracotomy is associated with intense pain attributable to the muscle-splitting incisions, rib retraction or resection, and damage to the intercostal nerves; and if poorly managed, it may worsen the pulmonary dysfunction experienced by these patients.1,2 Regional anesthetic techniques are strongly recommended3 primarily to reduce opioid use and the related adverse effects, including hypoventilation, sedation, nausea, and vomiting.
Thoracic epidural analgesia (TEA) and thoracic paravertebral block (TPVB) are currently the recommended first-line techniques for use in managing postthoracotomy pain.4 However, they can be technically challenging to perform and are associated with a significant failure rate (up to 15% in TEA).5 Options for rescue analgesia in this setting include intercostal blocks and systemic analgesics; however, both have their limitations.
We recently described a novel ultrasound-guided regional anesthetic technique, the erector spinae plane (ESP) block, and its application in patients with chronic thoracic neuropathic pain and acute surgical pain.6 In this case report, we present the first description of the use of a continuous ESP block for rescue analgesia after thoracic epidural failure in postthoracotomy pain.
Written informed consent was obtained from the patient for this report. A 78-year-old man with primary lung cancer was scheduled for thoracotomy and right lower lobectomy. His comorbidities included hypertension, chronic obstructive lung disease, and a hiatal hernia with peptic ulcer disease, all of which were well controlled on medication. In addition, he was taking up to 2 tablets of Tylenol 2 (acetaminophen/codeine 325 mg/15 mg) per day for back pain. Before surgery, a thoracic epidural catheter was inserted by a consultant anesthesiologist at the level of the T4 to T5 interspace using the right paramedian approach with a 17G Tuohy epidural needle. Loss of resistance to air was obtained during the first attempt, and a 19G epidural catheter was threaded 6 cm into the epidural space. A test dose of 2 mL of 2% lidocaine with 5 μg/mL of epinephrine was administered, followed by a bolus of 10 mL of 0.125% bupivacaine. General anesthesia was induced with intravenous (IV) propofol (100 mg), remifentanil (50 μg), and rocuronium (50 mg). Anesthesia was maintained with desflurane in an oxygen–air mixture, and a total of 3 mg of IV hydromorphone was administered for additional intraoperative analgesia. Intermittent epidural boluses of 5 mL of 0.125% bupivacaine were administered during surgery up to a total of 30 mL. The surgical procedure included a right posterolateral thoracotomy, major lung decortication, right lower lobectomy, mediastinal lymph node biopsy, and insertion of 2 chest drains. Intraoperative blood loss was 500 mL, and hemodynamic stability was maintained throughout surgery. The patient was successfully extubated at the end of surgery and transferred to the postanesthesia care unit (PACU) for further monitoring.
In the PACU, a continuous thoracic epidural infusion of 0.125% bupivacaine plus 5 μg/mL of fentanyl at the rate of 6 to 10 mL/h was initiated along with oral 650 mg of acetaminophen every 6 hours. The patient was not sufficiently alert and cooperative to allow PACU staff to ascertain whether there was a sensory block. However, the patient did complain of right-sided chest pain, for which he received a total of 0.6 mg of IV hydromorphone during his 2-hour stay in the PACU. He was discharged to a step-down unit with a pain score of 2/10 on a numerical rating scale (NRS). Overnight, he received 1 epidural top-up injection of 5 mL of 0.125% bupivacaine plus 5 μg/mL fentanyl and 2 doses of 0.5 mg of IV hydromorphone for rescue analgesia. When assessed by the acute pain service (APS) on the morning of postoperative day (POD) 1, the patient complained of significant surgical pain (NRS 8/10), and there was no discernible sensory block to cold testing over the surgical site. No improvement was seen after administration of an epidural bolus of 5 mL of 1% lidocaine. Primary failure of the epidural catheter was diagnosed. Because the patient was on dalteparin for deep venous thrombosis prophylaxis, resiting the epidural catheter was not attempted. Patient-controlled analgesia with hydromorphone was initiated instead, with a bolus setting of 0.2 mg, lockout interval of 8 minutes, and no background infusion. The APS team reviewed the patient on the morning of POD 2 and noted that he had not been using the patient-controlled analgesia appropriately because of confusion. He was still in significant pain and had used only 6 mg of hydromorphone over 12 hours. He was therefore started on a multimodal oral analgesic regime comprising 100 mg of gabapentin twice daily, 975 mg of acetaminophen hourly, and 1 to 2 mg of hydromorphone hourly as required, with additional doses of 0.3 to 0.5 mg of IV hydromorphone hourly as needed. The APS team also performed posterior intercostal nerve blocks at 6 levels, from T5 to T10 using 2 mL of 0.5% bupivacaine at each level. This significantly reduced the patient’s pain but only for approximately 8 hours, after which time the patient experienced excruciating pain of 10/10 NRS intensity, which was poorly controlled on systemic analgesia alone. At this point, the APS team sought the input of the lead author (M.F.), who decided to perform a right unilateral ESP block with catheter insertion for continuous infusion of local anesthetic in an effort to provide prolonged analgesia.
The procedure was performed at the patient’s bedside in the thoracic surgery inpatient unit, with pulse oximetry, electrocardiogram and noninvasive blood pressure monitoring. IV sedation was not administered. The patient was placed in a sitting position and a high-frequency linear ultrasound transducer (GE LOGIQe, Wauwatosa, Wis) was placed in a longitudinal parasagittal orientation 3 cm lateral to the T5 spinous process. The trapezius, rhomboid major, and erector spinae muscles were identified superficial to the tip of the T5 transverse process (Figure 1). A 17-gauge 8-cm needle (Arrow® StimuCath®; Teleflex Medical, Markham, Ontario, Canada) was inserted using an in-plane superior-to-inferior approach to place the tip into the fascial plane on the deep (anterior) aspect of erector spinae muscle. The location of the needle tip was confirmed by visible fluid spread lifting erector spinae muscle off the bony shadow of the transverse process (Figure 2). A total of 25 mL of 0.5% ropivacaine was injected in 5-mL aliquots through the needle, followed by insertion of a 19-gauge catheter under direct vision 5 cm beyond the needle tip. The catheter was secured in place, and a patient-controlled regional anesthesia local anesthetic infusion regimen was started with the following parameters: background infusion of 8 mL/h of 0.2% ropivacaine, bolus of 5 mL, and a lockout interval of 60 minutes. Fifteen minutes after completion of the block, the patient reported complete relief of pain from 10/10 to 0/10 as reported on the NRS.
The patient was reassessed 5 hours later, at which time his NRS pain score remained 0/10. A sensory assessment with the patient in the supine position revealed diminished perception of pinprick sensation in the T4 to T10 dermatomes extending from the right parasternal border to at least as far as the right posterior axillary line. The patient continued to demonstrate complete analgesia and a similar extent of loss to pinprick when assessed the next day (POD 3), 24 hours after block performance. The ESP catheter and infusion were maintained for 50 hours, during which time the patient did not require any additional doses of IV or oral hydromorphone. Local anesthetic use during this period averaged 10.5 mL/h inclusive of the background infusion and patient-controlled regional anesthesia boluses. At the time of catheter removal on POD 5, the patient reported NRS pain scores of 1/10 with activity and 0/10 at rest. The final sensory assessment revealed loss of pinprick sensation spanning the T2 to T10 dermatomes and extending to both the posterior and anterior hemithorax. The patient’s pain remained well controlled on oral multimodal analgesia, and he was discharged from the hospital on POD 7.
Both TEA and TPVB are recommended as first-line regional anesthetic techniques in the management of acute postthoracotomy pain.5,7 If either of these blocks are contraindicated or not possible, intercostal nerve block is currently the only other recommended regional anesthesia technique, to be used in conjunction with systemic opioid and nonopioid analgesia.5,7 Although intercostal nerve blocks can be highly effective, as they were here, they necessitate multiple injections and are generally only feasible as single-shot blocks, thus providing only a limited duration of analgesia.
The ESP block is a newly described technique that is capable of providing effective and extensive thoracic analgesia.6 Cadaveric data show that local anesthetic injected into the tissue plane deep to erector spinae muscle and superficial to the transverse processes and intertransverse connective tissues will penetrate anteriorly to anesthetize the spinal nerves. The sonoanatomy of the block and end point for needle insertion are readily appreciated, making it a relatively simple block to perform either as a single-shot block or a continuous technique, as demonstrated here. The confines of the erector spinae tissue plane promote extensive craniocaudal spread of local anesthetic,6 producing extensive analgesia from a single injection point or catheter site. Our previous investigation in fresh cadavers demonstrated that 20 mL injected at the level of T5 spreads from the T2 to T8 vertebral levels;6 we therefore chose in this case to inject a slightly larger volume of 25 mL as our initial bolus to ensure spread to the T9 to T10 dermatomes and analgesia of the chest drain insertion sites. From a safety perspective, the risk of pleural puncture and epidural spread is minimal compared with TEA and TPVB. Furthermore, the absence of major blood vessels and neural structures in the immediate vicinity minimizes concerns regarding development of a clinically significant hematoma. Nevertheless, until further clinical data accumulate, caution should be exercised in patients with a coagulation disorder or who are receiving perioperative anticoagulation for thromboprophylaxis.
It should be noted that the ESP block has some similarities to the ultrasound-guided retrolaminar block,8 mainly in the fact that injection occurs deep to erector spinae muscle in both instances, and that the retrolaminar block probably also works via diffusion of local anesthetic into the paravertebral space through the soft tissue gaps between adjacent vertebrae. Nevertheless, they are distinctly different techniques with completely different needle insertion sites and sonoanatomical targets; the retrolaminar block targets the lamina, and the ESP block targets the transverse process. In addition, the greater thickness and bulk of the erector spinae muscle overlying the lamina may hinder local anesthetic spread and thus clinical effect, as evidenced by a recent study showing it to be inferior to thoracic paravertebral blockade in providing analgesia after breast surgery.9
In summary, we believe that the ESP block has definite advantages over intercostal nerve block in the setting of postthoracotomy pain. It may also prove to be a viable alternative to both TPVB and TEA with potential advantages of safety and simplicity. Further studies are underway to confirm the efficacy of the ESP block in larger patient groups, as well as to determine the optimal dosing of both single-shot and continuous techniques.
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© 2017 International Anesthesia Research Society
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