Retrospective study of the clinical effect of incobotulinumtoxinA for the management of myofascial pain syndrome in refractory patients

Trapezius-rhomboid plane block for myofascial pain syndrome. Description of a new intervention

Introduction

Myofascial pain syndrome is a chronic pain condition prevalent in the general population. Muscular symptoms at the level of the trapezius and rhomboid muscles are frequent and the response to therapeutic interventions established so far is variable.

Methods

We present a case series of six patients who underwent a new technique of interfacial trapezius-rhomboid block (TRB) performed under ultrasonographic guidance by applying 10 cubic centimeters (cc) of analgesic solution (bupivacaine 0.25 % and methylprednisolone 40 mg) in the interfacial plane between the trapezius and rhomboid muscles at the level of the fifth and sixth ribs.

Results

At a follow-up of one and eight weeks, measurements of numerical rating scale (NRS) pain intensity were carried out, finding an average decrease of NRS pain intensity by 70 %.

Conclusion

This new technique may be considered for the treatment of myofascial pain syndrome of the trapezius and rhomboid muscles. Larger future studies are needed to better establish its safety and efficacy.

Intramuscular Innervation of the Supraspinatus Muscle Assessed Using Sihler’s Staining: Potential Application in Myofascial Pain Syndrome

Despite the positive effects of botulinum neurotoxin (BoNT) injection into the neural arborized area, there is no anatomical evidence in the literature regarding the neural arborization of the supraspinatus muscle. The present study aimed to define the intramuscular neural arborized pattern of the supraspinatus muscle using the modified Sihler’s staining method to facilitate the establishment of safe and effective injection sites in patients with myofascial pain in the supraspinatus muscle. Seventeen supraspinatus muscles from 15 embalmed cadavers were dissected. Precise suprascapular nerve entry locations were also observed. Intramuscular neural arborization was visualized by Sihler’s staining. The supraspinatus muscle was divided into four portions named A, B, C, and D. The nerve entry points were observed in 88.2% (15 of 17 cases) of section B and 76.5% (13 of 17 cases) of section C of the supraspinatus muscle, respectively. The concentration of intramuscular neural arborization was highest in section B of the supraspinatus muscle, which was the center of the supraspinatus muscle. When the clinician performs a trigger point and a BoNT injection into the supraspinatus muscle, injection within the medial 25–75% of the supraspinatus muscle will lead to optimal results when using small amounts of BoNT and prevent undesirable paralysis.