Pain Management Case of the Month: Treating Infraspinatus and Supraspinatus Trigger Points and Supraspinatus Tendinopathy Utilizing Shockwave Therapy

Myofascial trigger points can generate pain and dysfunction. This results in localized hypoxia and ischemia and the release of inflammatory mediators, which sensitize afferent nerve fibers accounting for the tenderness of the area.

Figure 1: Digital thermography before treatment

Figure 2: Digital thermography after treatment

by Heather Owen, DVM, MAV, CCRP, CCFT, MT

Myofascial trigger points are hyperirritable spots located in a taut band of skeletal muscle. They can generate pain and dysfunction and are often caused by mechanical stresses resulting in chronic muscle overload through injury, surgical trauma, neuropathy, joint dysfunction, or osteoarthritis. This results in localized hypoxia and ischemia and the release of inflammatory mediators, which sensitize afferent nerve fibers accounting for the tenderness of the area. On a palpation level, this feels like a golf ball or a hard knot in the muscle belly.

With the addition of shockwave and rehabilitation exercises, these patients are able to keep their muscle and musculocutaneous junction intact and are maintaining function. Some dogs respond to conservative management with shockwave, whereas for others, regenerative medicine or even rest and corticosteroid injection into the bursa or tendon can help. As many as 50% may never fully recover from the condition.

Signalment and History

The patient was a 10-year-old neutered male Great Pyrenees mix. The patient was presented for coxofemoral degenerative joint disease management when pharmaceuticals were not enough to keep him comfortable. He was slow to rise in the morning and was now limping on the right front limb. He was slipping on the hardwood floors at home and refusing to go up the stairs. He continued to go for one-mile leash walks daily but was unable to get up on furniture and had stopped playing.

Physical Examination and Diagnostics

On physical evaluation, he had decreased hip and shoulder extension. He was guarded on right shoulder extension and had myofascial trigger points in the right supraspinatus and infraspinatus muscles. There was pain on supraspinatus tendon palpation. Body condition score was 7/9 and a lameness score of 3/5 RH. The pain score was 2/4 according to the Colorado State University (CSU) Pain Scale. Digital thermography confirmed the physical evaluation findings. Radiographs and musculoskeletal ultrasound were obtained, and shockwave was applied to the trigger points as well as the supraspinatus tendon. A recheck musculoskeletal ultrasound was performed following the initial shockwave treatments to evaluate for resolution of trigger points and tendonitis. A rehabilitation program for the shoulder disease was initiated after resolution of disease, and disease-modifying nutraceuticals and antislip footing support were initiated as adjuncts to healing.

Musculoskeletal ultrasound images were obtained before any treatment was administered. Left and right supraspinatus fibers near the musculotendinous junction had an irregular fiber pattern. Musculoskeletal ultrasound diagnosis was supraspinatus insertional tendinopathy, grade I on the right side with bilateral infraspinatus and supraspinatus myofascial trigger points. The plan for treatment involved four treatments with shockwave over the supraspinatus tendon and the infraspinatus and supraspinatus muscles on both sides.

Figure 3, 4: Radiographs revealed mild osteophytes present on caudal humeral head

Treatment and Outcome

After four treatments with shockwave therapy, the musculoskeletal ultrasound revealed tendon healing and myofascial trigger point resolution. The patient’s pain scale decreased to a 1/4 on the CSU Pain Scale and rehabilitation was started to decrease lameness, increase function, and increase range of motion to shoulder and coxofemoral joints.

Land rehabilitation involving a land treadmill, lateral hill walking, and incline and decline walking in addition to lateral, incline, and decline standing were performed. Stand-to-down and down-to-stand exercises, walking up and down stairs, wobble board and rocker board (both in flexion/extension and abduction/adduction), and Cavaletti rails were implemented. Four shockwave treatments were performed in total. Rehabilitation is ongoing at monthly maintenance intervals owing to chronic degenerative joint disease of the coxofemoral joints.

Piezoelectric shockwave therapy was utilized to treat the myofascial trigger point present in the supraspinatus and infraspinatus muscle groups in addition to the inflamed musculotendinous junctions of both the infraspinatus and supraspinatus muscles. A 15-mm stand-off pad was utilized, and a frequency of 8 shocks/second for a total of 1,000 shocks at 0.1 mJ/mm2 for the trigger point and 0.2 mJ/mm2 for the supraspinatus tendon and infraspinatus tendon were utilized. Two treatments were needed for the trigger point, and four treatments were needed to resolve the tendonitis.

Figure 5: White circle: muscle fiber disorganization in supraspinatus muscle belly with hypoechoic areas within muscle fibers. Green dot: supraspinatus muscle

Figure 6: White circle: muscle fiber disorganization in supraspinatus muscle belly with hypoechoic areas within muscle fibers Green dot: supraspinatus muscle. Gray circle: hyperechoic debris within supraspinatus tendon near MT junction

Figure 7: Left infraspinatus muscle belly with hypoechoic areas and disruption of normal fiber pattern present

Figure 8: Normalizing fiber pattern of muscle bellies with reduction of hypoechoic areas

Rechecks of the patient were performed at two weeks and then every four weeks: These involved pain assessment, gait analysis, stance analysis, goniometry, Gulick tape measurements, myofascial palpation, digital thermography, and musculoskeletal ultrasounds.

Significant improvement in fiber pattern and orientation were already apparent in muscles.

Recheck of musculoskeletal ultrasound of the supraspinatus tendon and supraspinatus and infraspinatus eight weeks after starting shockwave therapy revealed a normal fiber pattern of infraspinatus and supraspinatus muscles, normal echogenicity of supraspinatus tendon, and decrease in overall size of supraspinatus tendon. Lameness score of the patient is 1/5 on right front. There was no pain on supraspinatus tendon palpation, and right shoulder extension had increased to near normal. To date, this patient is 0/5 lame and remains 0/4 on the CSU Pain Scale, and the owner describes him as back to “acting like a puppy.” He is able to run, jump, climb stairs, go for walks, and get up on furniture again. By incorporating a home exercise program, disease-modifying nutraceuticals, antislip flooring, and maintenance rehabilitation, this patient has not had any further pain or dysfunction.

Discussion and Conclusion

Muscle sprains, tendinopathies, and myofascial trigger points are common in practices. How we manage and treat these common occurrences is ever-evolving. Incorporating shockwave therapy early in the treatment of these conditions results in quicker resolution of pain, faster resolution of lameness and discomfort for the patient, and increased function of the muscles and tendons. While palpation of the myofascial structures can never be underestimated, being able to “see” the healing with the use of digital thermography and musculoskeletal ultrasound helps to give us more objective analysis of the resolution utilizing different modalities, including shockwave therapy, therapeutic ultrasound, and regenerative medicine, as we work together to further understand how to better treat our patients

Discussion by Mike Petty, DVM, CCRT, CVPP, DAAPM

Myofascial pain syndrome is a condition that previously only had treatment modalities like massage, dry-needling (insertion of an acupuncture needle into the affected area), and laser. With the advent of shockwave technology, we now have another treatment.

There are three types of shockwave therapies: electromagnetic, electrohydraulic, and piezoelectric. The two that are used most commonly in veterinary medicine are electrohydraulic and piezoelectric. Piezoelectric therapy, as mentioned in this article, has the advantage of being nonpainful to administer, but it is a lower strength and may require longer and more frequent therapies. Electrohydraulic is painful to administer and usually requires that the patient receive some kind of sedative plus pain medication before therapy, but it often only requires one or two treatments. If you are interested in using shockwave therapy in your practice, you should thoroughly investigate what type of unit you want to purchase.

Myofascial pain is rarely a condition onto itself; there is almost always some underlying or perpetuating cause, such as degenerative joint disease, acute injury to a joint or limb, or surgery, to name a few. Treatment of the myofascial pain is only temporary if the underlying cause is not adequately treated. This doesn’t mean myofascial pain treatment is not important; indeed, sometimes the myofascial pain is worse that the underlying issue. It does mean that you have to use your investigative skills to diagnose the underlying issue and set up a treatment plan.

Michael C. Petty, DVM, CCRT, CVPP, DAAPM, is in private practice in Canton, Michigan. He is a frequent national and international lecturer on topics related to pain management. Petty offers commentary on each Pain Case of the Month (and occasionally writes one himself). He was also a member of the task force for the 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats.
Heather Owen
Heather Owen, DVM, MAV, CCRP, CCFT, MT, is the owner of Animal Acupuncture and Canine Sports Medicine Facility in Tulsa, Oklahoma. She is certified in medical acupuncture along with being a certified canine rehabilitation practitioner, certified canine fitness practitioner, and a certified master trainer. She received her DVM from Oklahoma State University.

 

Photo credits: Photos courtesy of Heather Owen

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