Month: January 2021

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Serratus Anterior Plane Block for Thoracic Wall Pain

Background

 

The serratus anterior plane block (SAPB) is a field block that provides analgesia from T2 to T9 dermatomes of the hemithorax by anesthetizing the lateral cutaneous branches of the intercostal nerves in that area. It was first described in a 2013 study demonstrating long-lasting thoracic-wall anesthesia with no significant adverse effects (1). It has since been utilized by anesthesia for prophylactic treatment of post-thoracotomy and post-mastectomy pain (2-4) and has demonstrated utility for treatment of rib fracture pain in the acute setting (5). 

This case series describes its use in the Emergency Department (ED) for patients with thoracic wall pain from rib fractures, herpes zoster and chest tube placement. 

Serratus Anterior Plane Block in the Emergency Department: A Case Series.

Clinical Question

Is the SAPB feasible, safe and efficacious when used for a variety of thoracic wall pain syndromes in the ED?

Methods & Study Design

Case series in which six patients (age 60-94) underwent SAPB for treatment of thoracic pain.  Exclusion criteria were not specified; however, patients were included regardless of pre-procedural, multimodal analgesic use.  The authors recorded extent of injury and indication for SAPB. Outcomes of interest included efficacy of the nerve block and adverse events due to SABP during hospital stay.

SAPB was performed as follows: 25-30 mL of anesthetic (0.25% bupivacaine) was injected under ultrasound-guidance into the serratus anterior plane, either superficial (n=4) or deep (n=2) to the serratus anterior muscle. Sonographic landmarks for identification of the injection site included the lateral borders of the latissimus dorsi muscle and pectoralis muscle.

Image 1: Serratus anterior plane block sono-anatomy. Yellow line, target plane; purple-dotted line, needle; blue line, pleura. SCT, subcutaneous tissue; SAM, serratus anterior muscle; LDM, latissimus dorsi muscle; ICM, intercostal muscle (Lin et al 2020).

Results

SAPB was most commonly performed for pain related to anterior or posterior rib fractures (n=4), that was inadequately controlled with parenteral opioids.  SAPB provided complete or near-complete pain relief in these patients.  Additionally, SAPB resulted in significant pain relief for acute herpes zoster pain (n=1) and pre-procedural analgesia prior to tube thoracostomy (n=1).  Both superficial and deep injection locations resulted in effective analgesia.  No adverse events were noted.

Strength & Limitations

This is the first study to demonstrate efficacy of the SAPB for acute herpes zoster pain and procedural pain, and it adds to the growing body of literature supporting the use of SAPB for rib fracture pain. 

Limitations of this study include small sample size and lack of systematic data collection.  The authors note there is a possibility that physicians may not have documented all side effects.  Additionally, patients received non-standardized dosing of parenteral pain medication prior to SABP, therefore underdosing may have exaggerated the impact of the nerve block on pain relief.  Generalizability is limited as nerve blocks were performed by ultrasound fellowship-trained emergency physicians.

Authors Conclusion

“SAPB can be an effective analgesic modality for thoracic diseases and injuries including rib fractures, herpes zoster, and thoracostomy placement.”

Our Conclusion

SAPB was an effective adjunct to parenteral opioids in this case series.  Though limited, early data suggests that this is a safe and effective procedure.  Additional prospective studies are needed to compare SAPB to traditional techniques for the treatment of pain related to acute herpes zoster, thoracostomy, and rib fracture.

The Bottom Line 

 

Serratus anterior plane block, when performed by appropriately-trained physicians, is an effective and safe alternative to parenteral opioids and can provide significant, long-lasting analgesia for a variety of painful thoracic conditions. 

For more on the serratus anterior plane block see here:

Highland Ultrasound 

 

Authors

This post was written by Greta Davis, MS4 at UCSD School of Medicine, Charles Murchison, MD and Amir Aminlari MD. 

References

Lin J, Hoffman T, Badashova K, Motov S, Haines L. Serratus Anterior Plane Block in the Emergency Department: A Case Series. Clin Prac Cases Emerg Med. 2020 Feb;4(1):21-25.

1. Blanco R, Parras T, McDonnell JG, et al. Serratus plane block: a novel ultrasound-guided thoracic wall nerve block. Anaesthesia. 2013;68:1107-13.

2. Khalil AE, Abdallah NM, Bashandy GM, et al. Ultrasound-guided serratus anterior plane block versus thoracic epidural analgesia for thoracotomy pain. J Cardiothorac Vasc Anesth. 2017;31(1):152-8.

3. Rahimzadeh P, Imani F, Faiz SHR, et al. Impact of the ultrasound-guided serratus anterior plane block on post-mastectomy pain: a randomized clinical study. Turk J Anaesthesiol Reanim. 2018;46(5):388-92.

4. Madabushi R, Tewari S, Gautam SKS, et al. Serratus anterior plane block: a new analgesic technique for post-thoracotomy pain. Pain Physician. 2015;18(3):E421-4.

5. Durant E, Dixon B, Luftig J, et al. Ultrasound-guided serratus plane block for ED rib fracture pain control. Am J Emerg Med. 2017;35(1):197.e3-6.

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Case 26: Genicular Nerve Block for Knee Pain – A Novel Technique

A 68 year old female with no significant past medical history presents to the Emergency Department (ED) with one day of right knee pain after falling off her bicycle onto her right side. She was immediately unable to bear weight on her right leg. 

 

Vitals: T 98.3, HR 73, RR 18, BP 114/70, SpO2 99%

 

Right leg exam: mild right knee effusion. No ligamentous laxity. Tenderness to palpation over lateral joint line > medial joint line. Tenderness to palpation over proximal anterior tibia. Knee extension limited due to pain. Neurovascularly intact with soft compartments.

 

Radiographic imaging demonstrated an isolated right tibial plateau fracture depression of the lateral plateau. The patient reports she is in severe pain but dislikes taking both over-the-counter and opioid pain medications. 

What nerves may be targeted to provide pain relief to her knee while maintaining motor function? What anatomic landmarks should be used on ultrasound to identify the branches of this nerve?

Answer and Learning Points

The genicular nerves derive from various major lower extremity nerve branches (femoral, obturator, sciatic, tibial) nerves and provide sensation to the knee capsule and joint. Cadaveric studies suggest that most genicular nerves are easily identifiable landmarks that may be used for therapeutic purposes. 5  Genicular nerve blocks (GNB) are traditionally used in this setting of chronic osteoarthritis knee pain via radiofrequency ablation or perioperative knee pain via ultrasound (1-4, 9).

The use of a GNBs in the ED is a novel technique to provide motor-sparing, pain relief for acute knee pain. This 68 year old patient with an isolated lateral tibial plateau fracture reported 4/10 pain over her proximal tibia at rest and 8/10 over her proximal tibia with movement. Written informed consent was obtained for GNBs of her right knee. Anatomic landmarks for the superior lateral (Image A,B) , superior medial (Image C,D), and inferior medial (Image D,E,F) genicular nerves were identified on ultrasound.

genicular nerve block

genicular nerve block

genicular nerve block

The ultrasound probe was placed in the sagittal orientation for each site. The superior lateral genicular nerve was located on ultrasound at the junction of the lateral femoral epicondyle and the epiphysis of the shaft of the femur, adjacent to the superior lateral genicular artery (Image A,B). The superior medial genicular nerve (SMGN) can be identified on ultrasound at the junction of the medial femoral epicondyle and the epiphysis of the shaft of the femur, adjacent to the superior medial genicular artery (Image C, D). The inferior medial genicular nerve (IMGN) can be identified on ultrasound at the junction of the medial tibial epicondyle and the epiphysis of the shaft of the tibia, adjacent to the inferior medial genicular artery (Image E, F, G) (6-8).

Under ultrasound guidance and using sterile technique, the skin was first anesthetized with 1% lidocaine after each site. A 21-gauge, 2 inch echogenic needle was inserted percutaneously and advanced under ultrasound guidance using an out-of-plate technique to inject 1.5 mL of 0.5% bupivacaine around the right superior lateral, superior medial, and inferior medial genicular nerves. 

Learning points

    • Genicular nerves derive from several lower extremity nerves and supply sensory innervation to the knee. 
    • The superior lateral, superior medial, and inferior medial genicular nerves are commonly targeted for pain relief with chronic knee osteoarthritis and postoperative pain.
    • The SLGN, SMGN, IMGN are easily located on ultrasound using anatomic landmarks (junction between epicondyles and epiphysis of the femur and tibia, adjacent to paired genicular arteries).
    • To obtain the images, you can use the linear probe in the sagittal location over lateral femoral epicondyle, medial femoral epicondyle, and medial tibial epicondyle.

References

1. Ahmed, Arif. “Ultrasound-guided radiofrequency ablation of genicular nerves of knee for relief of intractable pain from knee osteoarthritis: a case series.” British Journal of Pain, vol. 12, no. 3, 2017, pp. 145-154, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6058456/. Accessed 18 November 2020.

2. Caldwell, George L. “Reduced Opioid Use After Surgeon-Administered Genicular Nerve Block for Anterior Cruciate Ligament Reconstruction in Adults and Adolescents.” HSS Journal, vol. 15, no. 1, 2019, pp. 42-50, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384209/. Accessed 18 November 2020.

3. Cankurtaran, Damla. “Comparing the effectiveness of ultrasound guided versus blind genicular nerve block on pain, muscle strength with isokinetic device, physical function and quality of life in chronic knee osteoarthritis: a prospective randomized controlled study.” Korean J Pain, vol. 33, no. 3, 2020, pp. 258 - 266, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336352/. Accessed 18 November 2020.

4. Erdem, Yusuf. “The Efficacy of Ultrasound-Guided Pulsed Radiofrequency of Genicular Nerves in the Treatment of Chronic Knee Pain Due to Severe Degenerative Disease or Previous Total Knee Arthroplasty.” Med Sci Monit, vol. 25, 2019, pp. 1857 - 1863, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423735/. Accessed 18 November 2020.

5. Fonkoué, Loïc. “Distribution of sensory nerves supplying the knee joint capsule and implications for genicular blockade and radiofrequency ablation: an anatomical study.” Surgical and Radiologic Anatomy, vol. 41, 2019, 1461–1471(2019), https://link.springer.com/article/10.1007/s00276-019-02291-y#citeas. Accessed 18 November 2020.

6. Güzelküçük, DemIr. “A different approach to the management of osteoarthritis in the knee: Ultrasound guided genicular nerve block.” Pain Medicine, vol. 18, no. 1, pp. 181 - 183, https://academic.oup.com/painmedicine/article/18/1/181/2924744. Accessed 18 November 2020.

7. Kim, Doo-Hwan. “Ultrasound-Guided Genicular Nerve Block for Knee Osteoarthritis: A Double-Blind, Randomized Controlled Trial of Local Anesthetic Alone or in Combination with Corticosteroid.” Pain Physician, vol. 21, 2018, pp. 41 - 51, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6058456/. Accessed 18 November 2020.

8. Protzman, Nicole. “Examining the feasibility of radiofrequency treatment for chronic knee pain after total knee arthroplasty.” PM&R, vol. 6, no. 4, 2014, pp. 373 - 376, https://pubmed.ncbi.nlm.nih.gov/24373908/. Accessed 18 November 2020.

9. Sahoo, Rajendra K. “Genicular nerve block for postoperative pain relief after total knee replacement.” Saudi J Anaesth, vol. 12, no. 2, 2020, pp. 235 - 237, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7164458/. Accessed 18 November 2020.

This post was written by Julia Sobel MD, with editing from Jessica Oswald MD, Charles Murchison MD and Amir Aminlari MD.

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