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

Localizing motor entry points of adductor muscles of thigh for motor point procedures in the treatment of adductor spasticity

Spasticity which is focal or segmental such as affecting a single muscle group or limb can be treated by chemical neurolysis or surgical denervation at the neurovascular hilus. This study determines the motor entry points (MEPs) of adductor muscles of the thigh in the adult Indian population and identifies precise anatomical landmarks for the successful performance motor point procedures for the relief of muscle spasticity. A total of 10 adult lower limbs were dissected, and nerve branches to adductor muscles were carefully exposed up to their MEP. The morphometry of adductor muscles, precise locations of proximal and distal MEPs, and ideal sites for motor point procedures were identified. The median number of MEPs in adductor longus was two. Most of them were located between 40% and 50% of the muscle length i.e., in the third-fifth of the total muscle length. Adductor magnus and gracilis had a median number of one and six MEPs respectively. The ideal site of motor point procedures is in the second-fifth of the muscle length for both. This preliminary study describes the location of MEPs and ideal sites of motor point procedures in the adductor muscle of the thigh. However, further cadaveric and electromyographic studies with larger samples are necessary to investigate precise locations of MEPs aiding in the treatment of spasticity.

Intramuscular neural distribution of the vastus medialis for botulinum neurotoxin injection: application to spasticity

PURPOSE

A comprehensive understanding of neural distribution within the vastus medialis is crucial for the effective administration of botulinum neurotoxin injections to manage spasticity. The aim of this study was to develop an anatomically informed approach to guide the administration of botulinum neurotoxin injections into the vastus medialis muscle.

METHODS

Using a modified Sihler's method, we examined the vastus medialis muscles (20 specimens) to delineate the distribution of nerves relative to a transverse line extending from the anterior superior iliac spine to the base of patella. The vastus medialis muscle was divided into 10 areas from top to bottom. Then, using two fresh cadavers, ultrasonography-guided injections were performed based on the distribution of nerves within the vastus medialis. Each specimen was subsequently dissected to verify if the dye was accurately directed to the most densely innervated regions of the vastus medialis and to assess the precision of the injections.

RESULTS

The intramuscular nerve distribution within the vastus medialis muscle showed distinct patterns, particularly in areas between 6 and 9. Four injections were successfully administered on each side, targeting the regions between 6 and 9 of the vastus medialis. Upon dissection of the cadavers, the dye was found to be distributed along the muscle fiber.

CONCLUSION

We recommend targeting botulinum neurotoxin injections toward regions displaying a prominent nerve distribution, specifically focusing on areas between 6 and 9. By adhering to these guidelines, clinicians can minimize doses and mitigate potential adverse effects, such as gait disturbances, antibody development, and bruising, resulting from multiple injections. Furthermore, these findings can be incorporated into electromyography practices.

The efficacy and safety of neubotulinumtoxinA for the treatment of forehead horizontal lines in Asians - A clinical, prospective, interventional, split-face study

BACKGROUND

Botulinum toxin injections are widely sought after in the field of medical aesthetics, offering consumers a variety of brand choices. Two commonly available botulinum toxin products, onabotulinumtoxinA and neubotulinumtoxinA, are featured in numerous clinics, leading many to question whether there are discernible differences in results, given their varying price ranges.

OBJECTIVE

To evaluate the efficacy and safety of neubotulinumtoxinA for the treatment of forehead horizontal lines.

METHODS

A 12-week prospective, single-centre, interventional split-face study was conducted, including 30 subjects. These enrolled subjects received a single treatment session, with neubotulinumtoxinA applied to the left side of the forehead and onabotulinumtoxinA to the right side. A superficial injection was performed in all individuals, where the product was injected subdermally in the frontalis muscle. Evaluation was conducted at baseline, 7 days, 14, days and 4, 8, and 12 weeks after treatment, both when the eyebrows were at maximum lift and in a resting position. Treatment efficacy was assessed by two physicians and self-assessed by the patients, using the Fitzpatrick Wrinkle Classification system. Adverse events were documented to evaluate safety.

RESULTS

The study found no statistically significant difference in the efficacy of neubotulinum and onabotulinum for treating forehead wrinkles, as indicated by p-values above 0.05 for both static and dynamic conditions. No safety and adverse events were observed in both formulations.

CONCLUSION

This study has demonstrated that neither formulation is inferior to each other in the treatment of forehead horizontal lines.

Sihler's staining technique: How to and guidance for botulinum neurotoxin injection in human muscles

The Sihler's stain is a whole-mount nerve staining technique that allows visualization of the nerve distribution and permits mapping of the entire nerve supply patterns of the organs, skeletal muscles, mucosa, skin, and other structures that contain myelinated nerve fibers. Unlike conventional approaches, this technique does not require extensive dissection or slide preparation. To date, the Sihler's stain is the best tool for demonstrating the precise intramuscular branching and distribution patterns of skeletal muscles. The intramuscular neural distribution is used as a guidance tool for the application of botulinum neurotoxin injections. In this review, we have identified and summarized the ideal botulinum neurotoxin injection points for several human tissues.

Anatomical Considerations for the Injection of Botulinum Neurotoxin in Shoulder and Arm Contouring

The utilization of botulinum neurotoxin in the field of body contouring is on the rise. Body contouring procedures typically focus on specific muscle groups such as the superior trapezius, deltoid, and lateral head of the triceps brachii. The authors propose identifying optimal injection sites for botulinum neurotoxin to achieve desired aesthetic contouring of the shoulders and arms. The authors conducted a modified Sihler's staining method on specimens of the superior trapezius, deltoid, and lateral head of the triceps brachii muscles, totaling 16, 14, and 16 specimens, respectively. The neural distribution exhibited the most extensive branching patterns within the horizontal section (between 1/5 and 2/5) and the vertical section (between 2/4 and 4/4) of the superior trapezius muscle. In the deltoid muscle, the areas between the anterior and posterior deltoid bellies, specifically within the range of the horizontal 1/3 to 2/3 lines, showed significant intramuscular arborization. Furthermore, the middle deltoid muscle displayed arborization patterns between 2/3 and the axillary line. Regarding the triceps brachii muscle, the lateral heads demonstrated arborization between 4/10 and 7/10. The authors recommend targeting these regions, where maximum arborization occurs, as the optimal and safest points for injecting botulinum toxin.

A practical guide to botulinum neurotoxin treatment of teres major muscle in shoulder spasticity: Intramuscular neural distribution of teres major muscle in cadaver model

BACKGROUND

Botulinum neurotoxin treatment typically focuses on the teres major muscle as a primary target for addressing shoulder spasticity. The muscle is located deep within a large muscle group and optimal injection locations have not been identified.

OBJECTIVE

To identify the preferred location for administering botulinum toxin injections in the teres major muscle.

METHODS

Teres major specimens were removed from 18 cadaveric models and stained with Sihler's method to reveal the neural distribution within the muscle. The muscles were systematically divided into equal lengths from origin to insertion. The neural density in each section was evaluated to determine the location that would be likely to increase effectiveness of the injection.

RESULTS

The greatest density of intramuscular nerve endings was located in the middle 20% of the muscle. The tendinous portion was observed at the ends of the muscle.

CONCLUSIONS

The results suggest that botulinum neurotoxin should be delivered in the middle 20% of the teres major muscle.

Distribution of the intramuscular innervation of the triceps brachii: Clinical importance in the treatment of spasticity with botulinum neurotoxin

This study aimed to identify ideal sites for botulinum toxin injection by analyzing the intramuscular nerve patterns of the triceps brachii muscles. A modified Sihler's method was applied to the triceps brachii muscle (15 specimens), with long, medial, and lateral heads. The intramuscular arborization areas of the long, medial, and lateral heads of the triceps brachii muscle were measured as a percentage of the total distance from the midpoint of the olecranon (0%) to the anteroinferior point of the acromion (100%), by dividing the medial and lateral parts based on the line connecting the midpoint of the olecranon and the anteroinferior point of the acromion. Intramuscular arborization patterns were observed at the long head at two medial regions, proximally 30%-50% and distally 60%-70%; medial head of 30%-40%; and lateral head of 30%-60%. These results suggest that the treatment of spasticity of the triceps brachii muscles involves botulinum toxin injections in specific areas. The areas corresponding to the areas of maximum arborization are recommended as the most effective and safe points for botulinum toxin injection.

Novel anatomical guidelines for botulinum neurotoxin injection in the mentalis muscle: a review

The mentalis muscle is a paired muscle originating from the alveolar bone of the mandible. This muscle is the main target muscle for botulinum neurotoxin (BoNT) injection therapy, which aims to treat cobblestone chin caused by mentalis hyperactivity. However, a lack of knowledge on the anatomy of the mentalis muscle and the properties of BoNT can lead to side effects, such as mouth closure insufficiency and smile asymmetry due to ptosis of the lower lip after BoNT injection procedures. Therefore, we have reviewed the anatomical properties associated with BoNT injection into the mentalis muscle. An up-to-date understanding of the localization of the BoNT injection point according to mandibular anatomy leads to better injection localization into the mentalis muscle. Optimal injection sites have been provided for the mentalis muscle and a proper injection technique has been described. We have suggested optimal injection sites based on the external anatomical landmarks of the mandible. The aim of these guidelines is to maximize the effects of BoNT therapy by minimizing the deleterious effects, which can be very useful in clinical settings.

Intramuscular neural distribution of the teres minor muscle using Sihler's stain: application to botulinum neurotoxin injection

The aim of this study was to elucidate the intramuscular arborization of the teres minor muslce for effective botulinum neurotoxin injection. Twelve specimens from 6 adult Korean cadavers (3 males and 3 females, age ranging from 66 to 78 years) were used in the study. The reference line between the 2/3 point of the axillary border of the scapula (0/5), where the muscle originates ant the insertion point of the greater tubercle of the humerus (5/5). The most intramuscular neural distribution was located on 1/5-3/5 of the muscle. The tendinous portion was observed in the 3/5-5/5. The result suggests the botulinum neurotoxin should be delivered in the 1/5-3/5 area of the teres minor muscle.

Introduction to the Toxins Special Issue on Botulinum Toxins: New Uses in the Treatment of Diseases

Studies on animals and humans have amply demonstrated the therapeutic efficacy of botulinum neurotoxins (BoNTs) in many pathologies [...].

Anatomical proposal of local anesthesia injection for median nerve block in treating hyperhidrosis with botulinum neurotoxin

INTRODUCTION

Hyperhidrosis, causing excessive sweat, can be treated with Botulinum neurotoxin injection. Botulinum toxin, an effective and safe treatment for hyperhidrosis, unfortunately involves significant pain due to multiple injections. This study aims to propose a more efficient and less painful approach to nerve blocks for relief, by identifying optimal injection points to block the median nerve, thereby enhancing palmar hyperhidrosis treatment.

METHODS

This study, involving 52 Korean cadaver arms (mean age 73.5 years), measured the location of the median nerve relative to the transverse line at the pisiform level to establish better nerve block injection sites.

RESULTS

In between the extensor carpi radialis and palmaris longus, the median nerve was located at an average distance of 47.39 ± 6.43 mm and 29.39 ± 6.43 mm from the transverse line at the pisiform level.

DISCUSSION

To minimize discomfort preceding the botulinum neurotoxin injection, we recommend the optimal injection site for local anesthesia to be located 4 cm distal to the transverse line of the pisiform, within the tendons of the palmaris longus and flexor carpi radialis muscles.

Guidance in botulinum neurotoxin injection for lower extremity spasticity: Sihler's staining technique

Spasticity is a motor disease characterized by a velocity-dependent acceleration in muscle tone or tonic stretch reflexes linked to hypertonia. Lower limb spasticity has been successfully treated with botulinum neurotoxin; however, the injection sites have not been generalized. Sihler's stain has been used to visualize intramuscular nerve distribution to guide botulinum neurotoxin injection. Sihler staining is a whole-mount nerve staining technique that allows visualization of nerve distribution and mapping of entire nerve supply patterns in skeletal muscle with hematoxylin-stained myelinated nerve fibers. This study reviewed and summarized previous lower extremity spasticity studies to determine the ideal injection site for botulinum neurotoxin.

Botulinum neurotoxin injection in the deltoid muscle: application to cosmetic shoulder contouring

BACKGROUND AND OBJECTIVES

This study describes the intramuscular nerve branching of the deltoid muscle in relation to shoulder surface anatomy, with the aim of providing essential information regarding the most appropriate sites for botulinum neurotoxin injection during shoulder line contouring.

METHODS

The modified Sihler's method was used to stain the deltoid muscles (16 specimens). The intramuscular arborization areas of the specimens were demarcated using the marginal line of the muscle origin and the line connecting the anterior and posterior upper edges of the axillary region.

RESULTS

The intramuscular neural distribution of the deltoid muscle had the greatest arborization patterns in the area between the horizontal 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line in middle deltoid bellies. The greatest part of the posterior circumflex artery and axillary nerve ran below the areas with the highest aborizations.

CONCLUSION

We propose that botulinum neurotoxin injections should be administered in the area between the 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line on middle deltoid bellies. Accordingly, clinicians will ensure minimal dose injections and fewer adverse effects of the botulinum neurotoxin injection. Deltoid intramuscular injections, such as vaccines and trigger point injections, should ideally be adapted according to our results.

Novel Anatomical Guidelines on Botulinum Neurotoxin Injection for Wrinkles in the Nose Region

Botulinum neurotoxin injection surrounding the nose area is frequently used in aesthetic settings. However, there is a shortage of thorough anatomical understanding that makes it difficult to treat wrinkles in the nose area. In this study, the anatomical aspects concerning the injection of botulinum neurotoxin into the nasalis, procerus, and levator labii superioris alaeque muscles are assessed. In addition, the present knowledge on localizing the botulinum neurotoxin injection point from a newer anatomy study is assessed. It was observed that, for the line-associated muscles in the nose region, the injection point may be more precisely defined. The optimal injection sites are the nasalis, procerus, and levator labii superioris alaeque muscles, and the injection technique is advised. We advise the best possible injection sites in association with anatomical standards for commonly injected muscles to increase efficiency in the nose region by removing the wrinkles. Similarly, these suggestions support a more precise procedure.