Are the Effects of Botulinum Toxin Injection on Myofascial Trigger Points Placebo Effects or Needling Effects?

Guidance to trigger point injection for treating myofascial pain syndrome: Intramuscular neural distribution of the quadratus lumborum

Postural habits and repetitive motion contribute toward the progress of myofascial pain by affecting overload on specific muscles, the quadratus lumborum (QL) muscle being the most frequently involved. The therapy of myofascial pain syndrome includes the release of myofascial pain syndrome using injective agents such as botulinum neurotoxin, lidocaine, steroids, and normal saline. However, an optimal injection point has not been established for the QL muscle. This study aimed to propose an optimal injection point for this muscle by studying its intramuscular neural distribution using the whole mount staining method. A modified Sihler's procedure was completed on 15 QL muscles to visualize the intramuscular arborization areas in terms of the inferior border of the 12th rib, the transverse processes of L1-L4, and the iliac crest. The intramuscular neural distribution of the QL had the densely arborized areas in the three lateral portions of L3-L4 and L4-L5 and the medial portion between L4 and L5.

Intramuscular Neural Distribution of the Serratus Anterior Muscle: Regarding Botulinum Neurotoxin Injection for Treating Myofascial Pain Syndrome

The serratus anterior muscle is commonly involved in myofascial pain syndrome and is treated with many different injective methods. Currently, there is no definite injection point for the muscle. This study provides a suggestion for injection points for the serratus anterior muscle considering the intramuscular neural distribution using the whole-mount staining method. A modified Sihler method was applied to the serratus anterior muscles (15 specimens). The intramuscular arborization areas were identified in terms of the anterior (100%), middle (50%), and posterior axillary line (0%), and from the first to the ninth ribs. The intramuscular neural distribution for the serratus anterior muscle had the largest arborization patterns in the fifth to the ninth rib portion of between 50% and 70%, and the first to the fourth rib portion had between 20% and 40%. These intramuscular neural distribution-based injection sites are in relation to the external anatomical line for the frequently injected muscles to facilitate the efficiency of botulinum neurotoxin injections. Lastly, the intramuscular neural distribution of serratus anterior muscle should be considered in order to practice more accurately without the harmful side effects of trigger-point injections and botulinum neurotoxin injections.

Myofascial low back pain

Low back pain is a common condition that is encountered by both primary care physicians as well as various specialists, which include: orthopedic surgeons, physical medicine and rehabilitation specialists, neurologists, rheumatologists, and pain management specialists. Associated muscular pain is very common and often a reactive response from nociception from other structures. Myofascial pain may arise, which is characterized by the presence of myofascial trigger points (MTrPs) that are located in fascia, tendons, and/or muscle. This article reviews the current evidence regarding the pathophysiology, assessment, and recommended treatment options for myofascial low back pain.

Myofascial low back pain: a review

Myofascial pain syndrome is a common nonarticular local musculoskeletal pain syndrome caused by myofascial trigger points located at muscle, fascia, or tendinous insertions, affecting up to 95% of people with chronic pain disorders. Clinically, myofascial pain syndrome can present as painful restricted range of motion, stiffness, referred pain patterns, and autonomic dysfunction. The underlying cause is often related to muscular imbalances, and following a thorough physical examination the condition should be treated with a comprehensive rehabilitation program. Additional treatment options include pharmacologic, needling with or without anesthetic agents or nerve stimulation, and alternative medicine treatments such as massage or herbal medicines. Repeated trigger point injections should be avoided, and corticosteroids should not be injected into trigger points.

Comparison of miniscalpel-needle release, acupuncture needling, and stretching exercise to trigger point in myofascial pain syndrome

OBJECTIVE

Myofascial pain syndrome (MPS) is one of the most common causes of chronic musculoskeletal pain. Several methods have been recommended for the inactivation of trigger points (TrPs). We carried out this study to investigate the effectiveness of miniscalpel-needle (MSN) release and acupuncture needling and self neck-stretching exercises on myofascial TrPs of the upper trapezius muscle.

METHODS

Eighty-three TrPs in 43 patients with MPS were treated and randomly assigned to 3 groups: group 1 received MSN release in conjunction with self neck-stretching exercises; group 2 received acupuncture needling treatment and performed self neck-stretching exercises; and group 3, the control group, was assigned self neck-stretching exercises only. The therapeutic effectiveness was evaluated using subjective pain intensity (PI) with a visual analog scale, pressure pain threshold (PPT), and contralateral bending range of motion (ROM) of cervical spine at pretreatment, 2 weeks, and 3 months after treatment.

RESULTS

The improvement of PI, PPT, and contralateral bending ROM of cervical spine was significantly greater in group 1 and 2 than that in control group at 2 weeks and 3 months follow-up. Compared with group 2, patients in group 1 had a statistically significant reduction in PI, an increase in PPT, contralateral bending ROM of cervical spine at 3 months follow-up.

DISCUSSION

The effectiveness of MSN release for MPS is superior to that of acupuncture needling treatment or self neck-stretching exercises alone. The MSN release is also safe, without severe side effects in treatment of MPS.