The erector spinae plane (ESP) block was initially described by Chin et al1 in 2016 as an intervention for treating chronic thoracic neuropathic pain. It is an interfascial plane block whereby local anesthetic is injected within the plane deep to the erector spinae muscles and superficial to the transverse process. Local anesthetic spreads craniocaudally over several vertebral levels leading to a multidermatomal sensory block. Subsequent reports of the ESP block have described its use for postoperative analgesia in surgery of the thoracic, abdominal, and lumbar regions.1–3 It has also been used as the primary anesthetic for breast surgery.4
We present the first reported case of the ESP block being used to provide surgical anesthesia in the cervical region. Written consent for publication has been obtained from the patient.
A 50-year-old man was admitted under the general surgical team with a large, infected sebaceous cyst overlying the spinous processes of C2–4 (Figure 1). Antibiotic treatment failed to demonstrate any benefit. The patient reported a numerically rated pain score of 7 of 10 at rest and 10 of 10 on movement, despite regular paracetamol and oral morphine. The surgeon abandoned incision and drainage under local anesthetic tissue infiltration because the patient could not tolerate it.
The patient had several risk factors for general anesthesia. He had a predicted difficult airway with a body mass index of 50, obstructive sleep apnea (for which he uses nocturnal continuous positive airway pressure therapy), and a thick beard. The patient’s progressing infection had resulted in a degree of fixed flexion of his neck and severely limited neck extension, secondary to edema and pain. After a discussion on the risks and benefits of general versus regional anesthesia, the patient strongly favored a regional approach.
Informed consent was given and standard monitoring applied. A bilateral, ultrasound-guided ESP block was performed at the level of T2 with the use of a SonoSite Edge Ultrasound machine (FUJIFILM SonoSite, Bothell, WA), a SonoSite rC60xi curvilinear probe (FUJIFILM SonoSite, Bothell, WA), and a 100-mm 20g Stimuplex Ultra 360 needle (B. Braun, Melsungen, Germany).
We used an in-plane approach, mirroring the technique described by Chin et al.1 However, the needle direction was caudad-to-cephalad owing to the location of the abscess. The needle was seen to pass through the trapezius, rhomboid, and erector spinae muscles (Figure 2). Hydrolocation of the plane with small volumes of local anesthetic just superficial to the transverse process confirmed needle tip position. Twenty milliliters of ropivacaine 0.375%, lignocaine 1%, and adrenaline 1:400,000 were injected on each side. Formal testing with ethyl chloride 15 minutes after block insertion demonstrated loss of cold sensation over the C4 to T4 dermatomes on the left and significantly reduced sensation to cold on the right.
The patient was given a single, preincision 0.5 mg bolus of midazolam intravenously as well as 20–30 mg of ketamine intravenous boluses both preemptively and intra operatively to provide sedation (total ketamine 120 mg). The surgeon excised an abscess that was 8 cm in diameter and 3 cm deep. The patient tolerated the procedure very well. Verbal contact was maintained throughout.
The surgeon attempted to incise a smaller, noninfected cyst in the midthoracic region located beyond the boundaries of the block, but the patient could not tolerate this; therefore, further local infiltration of local anesthetic by the surgeon was required. Six hours postoperatively, the patient reported a numerically rated pain score of 1 of 10 at rest and 3 of 10 on movement. He required no further opiate analgesia. He was very satisfied with how the procedure had been undertaken.
The use of the ESP block transformed the anesthetic approach in this patient. It provided a safe and satisfactory regional anesthetic technique for a patient who would be a high-risk candidate for a general anesthetic. Furthermore, avoiding a general anesthetic aligned well with the patient’s own values and wishes, informed by his awareness of the associated risks.
Our use of midazolam and ketamine yielded a cooperative and comfortable patient who maintained verbal contact throughout. We recognize that the analgesic properties of ketamine could potentially mask failure of the ESP block to provide anesthesia. However, when the surgeon tried to repeat the procedure on another noninfected cyst in the midthoracic region beyond the dermatomal spread of the block (Figure 1), the patient could not tolerate this before further local anesthetic infiltration into surrounding tissue. This provides further confirmation of the efficacy of the ESP block in this case.
The ESP block is a relatively new regional anesthesia technique; with novelty comes uncertainty. A significant drawback of the technique is the lack of evidence with regard to both its efficacy and safety. We welcome the findings of 2 recent randomized controlled trials evaluating the effectiveness of the ESP block. Tulgar et al5 concluded that patients receiving an ESP block before laparoscopic cholecystectomy had improved numerical rating scale pain scores compared to those receiving paracetamol and tenoxicam alone. Krishna et al6 demonstrated improved numerical rating scale pain scores for patients receiving ESP block for cardiac surgery compared to those receiving paracetamol and tramadol. It is encouraging that the authors reported no complications relating to the use of the ESP block. Indeed, there have been no reports of complications arising from the use of ESP block in the literature to date. Unfortunately, there is a lack of comparative data regarding other techniques, such as surgical local infiltration, quadratus lumborum, paravertebral, and neuraxial blocks.
Detailed cadaveric examination has highlighted variability in the spread of injectate. The most detailed of these studies,7 in which 10 cadavers were dissected after bilateral ESP blocks (with methylene blue) under ultrasound guidance, demonstrates consistent involvement of the dorsal rami as they exit the costotransverse foramen over several vertebral levels. Only 5% of blocks (1 out of a total of 20 blocks performed) resulted in anterior spread of dye to involve the ventral rami with no tracking of dye into the paravertebral space. Ivanusic et al7 concludes that the clinical effects of the ESP block are likely due to the blocking of dorsal rami as they exit the costotransverse foramen to innervate the medial skin and medial muscles of the back. He suggests that the clinical observation that the ESP block also results in sensory blockade of the lateral and anterior aspect of the chest wall may be explained by the possible involvement of the lateral cutaneous branches of the intercostal nerves.
The team who pioneered this block, Chin et al,1 conducted a similar examination with 2 cadavers. He found that there was anterior spread of methylene blue through the costotransverse foramina to the region of the spinal nerves and the origins of the dorsal and ventral rami. This discrepancy raises concerns with regard to the potential consistency of the block. Elsharkawy et al8 recently provided a thorough analysis of the potential causes of such variability in interfascial plane blocks, such as exact needle placement and patient positioning. It is notable, for example, that Ivanusic et al7 placed the cadavers in the prone position while performing the block, whereas Forero et al9 positioned the cadavers in a sitting position. As Elsharkawy et al8 conclude, such variation highlights the need for a more thorough understanding of the functional anatomy and structure of facial tissue.
Conversely, the ESP block has unquestionable advantages. The sonoanatomy is easily recognizable, even in the patients who are obese. In common with other fascial plane blocks, needle misplacement is unlikely to damage nearby structures. It can be performed relatively quickly with the patient in either the prone, lateral, or sitting position. Furthermore, the block lends itself well to the use of indwelling catheters, thus increasing the duration of the analgesic effect.
The limits of the ESP block are still being explored. This is the second case report highlighting the use of the ESP block in providing complete anesthesia for a surgical procedure. Remarkably, Kimachi et al4 successfully used an ESP block as the sole anesthetic modality in a patient undergoing a right-sided mastectomy and axillary dissection. The block was pioneered as an intervention for chronic thoracic pain.9 It has since been successfully used for treating chronic shoulder pain.10 We wonder whether the use of the ESP block in the cervical region may have further applications in the chronic pain setting. For example, might it be used as a safer alternative to cervical facet joint injections? Each facet joint is supplied by both the dorsal rami above and the dorsal rami below. If (as Ivanusic et al7 conclude) the block primarily targets the dorsal rami, its multilevel spread could have particular benefit here.
This case report adds to the rapidly growing list of indications of the ESP block. Its popularity has undoubtedly been propelled by both the ease and speed with which it can be performed. Its low-risk profile also makes it particularly attractive. We look forward to the continuing research that compares the efficacy of the ESP block to other analgesic options and that examines more closely the safety of this novel regional anesthetic technique.
Name: Hywel T. Evans, FRCA.
Contribution: This author helped compile the information and write all versions of the manuscript.
Name: Gavin J. Leslie, MBBCh.
Contribution: This author helped compile the information and write the first draft.
Name: Olga Rutka, FRCS.
Contribution: This author helped submit the information and review the manuscript.
Name: Edward Keevil, FRCA.
Contribution: This author helped write and review the manuscript.
Name: David Burckett-St Laurent, FRCA.
Contribution: This author helped care for the patient, coordinate the authors, and edit the mansucript.
This manuscript was handled by: BobbieJean Sweitzer, MD, FACP.
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