Erector spinae plane block: A safe,simple and effective alternative for knee surgery

Abstract

Neuraxial anaesthesia techniques are routinely used to manage postoperative pain in patients undergoing lower limb orthopaedic surgery. However, neuraxial anaesthesia is contraindicated in patients with a deformed spine or coagulopathy. Researchers recently described the erector spinae plane block—a safe, easy and effective interfascial plane block for managing chronic thoracic pain. Since then, it has been used for providing analgesia in thoracic, abdominal and hip surgery. We report its analgesic use in two patients undergoing knee surgery: one with lumbar scoliosis undergoing above knee amputation, and the other with haemophilia undergoing bilateral knee arthroplasty.

Introduction

In 2016, Forero et al. ¹ described a new interfascial plane block, the erector spinae plane (ESP) block, in two patients with thoracic neuropathic pain. They described it as a safe and effective block which produced multidermatomal sensory loss. Various authors later reported its usefulness in providing analgesia for thoracic, abdominal and hip surgery,^2–8 as the injected drug spread to multiple vertebral levels. We report its use as an analgesic technique in two patients undergoing knee surgery: one with lumbar scoliosis undergoing above knee amputation, and the other with haemophilia undergoing bilateral knee arthroplasty. Written informed consent was obtained from the two patients for publication.

Case 1

An 18-year-old female weighing 43 kg diagnosed with osteosarcoma of the proximal tibia was admitted for above knee amputation. Physical examination revealed thoracolumbar scoliosis with normal cardiopulmonary reserve. Her chest X-ray showed slight crowding of the lower ribs towards the right side. However, her pulmonary function tests, electrocardiogram, echocardiogram and other routine investigations were normal. We initially chose to try epidural analgesia for postoperative pain management, but after three failed attempts, we decided to perform an ultrasound (US)-guided continuous ESP block. The block was performed successfully at the T12 transverse process with an 18G Tuohy needle using a high-frequency linear transducer (6–13 MHz, M-Turbo; SonoSite, Bothell, WA, USA). A 20 mL bolus of 0.25% bupivacaine was administered, and a catheter was inserted inside the plane. We started an infusion of 0.125% bupivacaine at 5 mL/h intraoperatively which was continued for two days. General anaesthesia was induced, and surgery lasted for 90 minutes. A total of 200 µg of intravenous (IV) fentanyl as intermittent boluses and 1 g of IV paracetamol was given during surgery. After extubation, the patient had no pain, and her verbal numerical rating score (VNRS) was <2/10. Sensory testing using a cold spirit swab revealed complete loss of temperature sensation to the distal part of the amputated stump (L3–4). The patient was also given 1 g of IV paracetamol and 50 mg of IV tramadol three times a day for the remaining two days of her hospital stay. She remained comfortable, and her VNRS remained <4/10 for the two days.

Case 2

A 26-year-old male patient weighing 70 kg who had chronic bilateral recurrent haemarthrosis was admitted for bilateral knee replacement. The patient had been previously diagnosed with haemophilia A, and on investigation, his factor VIII assay was <1% of normal, and the activated partial thromboplastin time (APTT) was 93 seconds. The other coagulation parameters and routine investigations were within normal limits. After consultation with a haematologist, the patient was prescribed 3500 IU of IV factor VIII twice daily with a target of 100% correction before surgery. However, the haematologist declared the patient fit for surgery with 80% correction of factor VIII and a normal APTT after four days of treatment. Considering the risk of epidural haematoma associated with neuraxial anaesthesia, we decided to administer a single bolus dose bilateral US-guided ESP block for postoperative pain, followed by general anaesthesia. Twenty millilitres of 0.25% bupivacaine was injected over the transverse process and beneath the erector spinae muscle of the first lumbar vertebra on each side. Testing at 30 minutes revealed no sensation of a cold swab or pinprick at the medial aspect of the sole of the foot (L4–5 level). Thereafter, general anaesthesia was induced with 100 µg of IV fentanyl, 100 mg of IV propofol and 30 mg of IV atracurium Anaesthesia was maintained with isoflurane and intermittent boluses of fentanyl and atracurium. Surgery continued for two hours without any unexpected blood loss. The patient received a total of 250 µg of fentanyl and 1 g of IV paracetamol intraoperatively. After extubation, the patient did not complain of any significant pain. His VNRS was <3/10, and he only complained of mild pain on movement. We started an IV morphine patient-controlled analgesia pump without any background infusion. The patient did not require any opioids for 12 hours, and his total morphine consumption was 6 mg for the first postoperative day.

Discussion

The erector spinae is a vertical group of muscles extending from the occiput above to the sacrum below. The ESP block is an US-guided interfascial plane block wherein local anaesthetic is deposited beneath the erector spinae muscle over the transverse processes of the vertebrae. The drugs have been shown to spread extensively along multiple dermatomal levels.

In 2016, Forero et al. injected local anaesthetic at the transverse process of the fifth thoracic vertebra in a patient suffering from thoracic neuropathic pain. This produced effective analgesia and sensory block from T2 to T9. ¹

Thereafter, Chin et al. reported successful use of the ESP block on the transverse process of the seventh thoracic vertebra to manage perioperative pain in four patients undergoing laparoscopic ventral hernia repair. They discovered that radio-opaque contrast injectate spread from upper thoracic to the L2–L3 intervertebral space caudally using computerised tomography in a freshly prepared cadaver. ⁶ They concluded that ESP block given at the T7 transverse process is a promising regional technique to manage perioperative pain even for infraumbilical abdominal surgeries.

Hironobu et al. also investigated the spread of radiocontrast agent and local anaesthetic solution in an ESP block given at the T6 transverse process in three lung cancer patients. They observed the spread of contrast and loss of temperature and pinprick sensation. They hypothesised that ESP block administered at this level spreads to more than five intervertebral spaces from the injection site. ⁹

Thereafter, ESP block was successfully reported for various thoracic and abdominal surgeries at various levels.^2–5 Tulgar et al. recently also reported the use of the ESP block at L4 for hip arthroplasty and proximal femur surgery.^7,8 They successfully performed continuous ESP block in 11/12 patients undergoing hip arthroplasty or proximal femur surgery. ⁸ In one patient requiring contrast tomography for orthopaedic reasons, they injected 30 mL of contrast via a catheter inserted at the L4 vertebral level deep to the erector spinae muscle and reported extensive spread from the T12 to S1 intervertebral space. They even found the spread of contrast to the lumbar plexus.

Our preferred analgesic technique for the two cases described in this report would typically have been epidural analgesia. However, both cases had contraindications to epidural insertion.

We performed a continuous ESP block at T12 in a patient with osteosarcoma posted for above knee amputation after several failed attempts at epidural. Similarly, we performed bilateral ESP block at the L1 transverse process in a patient with haemophilia undergoing bilateral total knee arthroplasty. Postoperatively, both patients were extubated with a VNRS of <4/10 and did not require rescue analgesia. ESP block at T12 showed no sensation of cold to L4, while the block at L1 produced sensory loss to the L5 dermatome.

We were concerned about the use of the ESP block in our patient with haemophilia, since this is a relatively new block, and we were not able to find literature stating the risk of haematoma. However, the ESP block is performed in a plane deep to the erector spinae muscle over the transverse process. This plane is devoid of any vascular or vital structures and is therefore considered safe. Further, continuous ultrasonic visualisation of needle insertion increases the safety of this technique.

In view of the limited literature discussed above and our clinical experience of two cases, it appears that the ESP block may be a safe, simple and effective technique for analgesia following surgery around the knee. However, this is a clinical report of two cases, and further studies are required to prove its safety, simplicity and effectiveness in patients with contraindications to epidural analgesia for knee surgery.