3/19/2019

Trigger Point Injection

Brian Shian, MD, FHM Department of Family Medicine University of Iowa Hospitals and Clinics

Objectives

• Discuss the definition and diagnosis criterial • Explore possible pathophysiology • Identify the role of Ultrasound in evaluation and treatment • Review agents used for local injection • Demonstrate ultrasound guided injection

What is a Trigger Point (TrP)?

A TrP is generally considered a localized spot in theskeletalmusclewithwhichofthefollowing characteristic? A. Tenderness under B. Palpable nodule in a taut band C. Tenderness, and twitch with compression D. No consensus

Travell, Janet; Simons David; Simons Lois (1999). Myofascial Pain and Dysfunction: The Trigger Point Manual (2 vol. set, 2nd Ed.). USA: Lippincott Williams & Williams

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Trigger Point

• Discrete, focal, hyperirritable spots located in a taut band of . • Painful on compression and can produce referred pain, referred tenderness, motor dysfunction, and autonomic phenomena. • Hypothetical and unproven etiology

Simons DG, Travell JG, Simons LS. Travell & Simons' Myofascial pain and dysfunction: the trigger point manual. 2d ed. Baltimore: Williams & Wilkins, 1999:5.

Related Terms

• Taut band • Active trigger point • Latent trigger point • Key trigger point • Satellite point • Jump sensation or sign

Margulis, RK. Tandem Point(SM) Therapy: An integrated approach for myofascial pain. NIH Grand Rounds, March 17, 2000. http://www.tandempoint.com/p2.htm

Myofascial Pain Syndrome (MPS)

• Coined by Dr. Travell & David Simons in 1982 • No laboratory test to assist the diagnosis • Diagnosis is currently made by identifying a TrP in a person – whose pain is consistent with the pain of a TrP and – whose pain is reproduced in part by activation of the TrP.

Travell J, Simons D. Myofascial Pain and Dysfunction, Vol. 1: The Trigger Point Manual, the Upper Extremities. Baltimore: Williams & Wilkins; 1982.

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Pathophysiology

• Integrated Hypothesis: – A disruption of Ach metabolism equilibrium caused persistent muscle contraction which cause muscle – Injured muscle release substance to activate muscle nociceptors and cause pain – This theory remains conjecture in the face of conflicting data

Quintner JL, etc. A critical evaluation of the trigger point phenomenon. (Oxford). 2015 Mar;54(3):392‐9.

TrP: Intertester Reliability

Nice DA, etc. Intertester reliability of judgments of the presence of trigger points in patients with low back pain. Arch Phys Med Rehabil. 1992 Oct;73(10):893‐8.

TrP Under POCUS

Sikdar S, et al. Assessment of Myofascial Trigger Points (MTrPs): A New Application of Ultrasound Imaging and Vibration Sonoelastography 30th Annual International IEEE EMBS Conference Vancouver, British Columbia, Canada, August 20‐24, 2008

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Proposed Diagnosis Criterials

• Based on a Delphi study, a panel agreed that two palpatory and one symptom criteria for the identification of a TrP: I. a taut band II. a hypersensitive spot III. referred pain

I and II applied to both active and latent TrPs III could include pain, or other sensations, such as tingling or numbness.

• A TrP should meet at least two criterial

Fernandez‐de‐las‐Pe~nas C, Dommerholt J.International consensus on diagnostic criteria and clinical considerations of myofascial trigger points: A Delphi Study. Pain Med 2017;19(1):142–50.

Common Trigger Point Locations

• Occipital area • Upper back • Lower back • Abdominal wall • Facial TMJ

Pfenninger GL, Fowler GC. (1994). Procedures for Primary Care . St. Louis, MO: Mosby, Inc.

Trigger Point Management

• Non‐invasive – compression – spray and stretch – TENS – High intensity focused US • Invasive – Local injection – –

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Trigger Point Injection (TPI)

• A common treatment modality • Mechanic effect • Chemical effect – Vasodilation – Dilution & removal toxic material – Inhibit Ach release

Pfenninger GL, Fowler GC. (1994). Procedures for Primary Care Physicians. St. Louis, MO: Mosby, Inc.

TPI Indication

• Unexplained localized pain • Migraine • Renal colic • Primary dysmenorrhea • Nocturnal cal cramps • ?

TPI Contraindication

• Injection site • Concomitant use of an anticoagulation • Hemorrhagic syndrome • Septicemia • Resuscitation equipment not available • Significant psychiatric disturbance

Pfenninger GL, Fowler GC. (1994). Procedures for Primary Care Physicians. St. Louis, MO: Mosby, Inc.

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TPI Complications

• Local complication – Myositis ossificans – Intramuscular hematoma • Wrong structure – Neurovascular injury • Wrong depth: – Intrathecal injection – Pneumothorax – Descending necrotizing mediastinitis

Injection Agents

• – , ropivacaine w/wo dexamethasone – New local anesthetics • Saline • 5‐HT3 receptor antagonist tropisetron • Botulism toxin A/Dysport • Levosulpiride

Special Site Injection

• Great occipital nerve • Anterior abdominal cutaneus nerve • Lumbar plexus • Pudendal nerve • Dorsal ramus of spinal nerve

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ACNES Injection

Predict Injection Failure

Hopwood MB, Abram SE. Factors associated with failure of trigger point injections. Clin J Pain. 1994 Sep;10(3):227‐34.

Dry Needling

Patients treated with dry needling had postinjection soreness of significantly greater intensity and longer duration than those treated with injection

Hong CZ. Lidocaine injection versus dry needling to . The importance of the local twitch response. Am J Phys Med Rehabil. 1994 Jul‐Aug;73(4):256‐63.

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Other Interventions

• • Bloodletting • Extracorporeal Shock Wave Therapy • Kinesiology taping • EMG guided trigger point injections

POCUS Role

• To identify trigger points • To rule out other pathologies • To localize key structures or organs • To safely guide local injection

POCUS Guided TrP Injection Demo

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Thanks

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