Muscle fiber orientation in muscles commonly injected with botulinum toxin: an anatomical pilot study

Optimizing Botulinum Toxin A Administration for Forehead Wrinkles: Introducing the Lines and Dots (LADs) Technique and a Predictive Dosage Model

This study introduces the Lines and Dots (LADs) technique, a new approach for administering botulinum toxin type A (BoNT-A) in treating forehead wrinkles. (1) Background: BoNT-A application patterns in the forehead often rely solely on the anatomy of the frontalis muscle. The LADs technique proposes a combination of anatomical features with nerve pathways. (2) Methods: The technique employed a grid system aligned with the supraorbital and supratrochlear nerve pathways and used an electronic acupuncture pen for validation. This study analyzed treatment outcomes for efficacy and safety and proposed a predictive model for BoNT-A dosage. (3) Results: LADs was associated with a high satisfaction rate and low side effect incidence. The predictive model followed BoNT-A Units=0.322×Muscle Pattern Code+1.282×Line Type Code+2.905×Severity Pre-Treatment+3.947. (4) Conclusions: The LADs technique offers an alternative approach to treating forehead wrinkles, optimizing efficacy while minimizing the BoNT-A dose required.

Rectus Femoris Characteristics in Post Stroke Spasticity: Clinical Implications from Ultrasonographic Evaluation

In stroke survivors, rectus femoris (RF) spasticity is often implicated in gait pattern alterations such as stiff knee gait (SKG). Botulinum toxin type A (BoNT-A) is considered the gold standard for focal spasticity treatment. However—even if the accuracy of injection is crucial for BoNT-A efficacy—instrumented guidance for BoNT-A injection is not routinely applied in clinical settings. In order to investigate the possible implications of an inadequate BoNT-A injection on patients’ clinical outcome, we evaluated the ultrasound-derived RF characteristics (muscle depth, muscle thickness, cross-sectional area and mean echo intensity) in 47 stroke survivors. In our sample, we observed wide variability of RF depth in both hemiparetic and unaffected side of included patients (0.44 and 3.54 cm and between 0.25 and 3.16 cm, respectively). Moreover, our analysis did not show significant differences between treated and non-treated RF in stroke survivors. These results suggest that considering the inter-individual variability in RF muscle depth and thickness, injection guidance should be considered for BoNT-A treatment in order to optimize the clinical outcome of treated patients. In particular, ultrasound guidance may help the clinicians in the long-term follow-up of muscle quality.

Over 25 Years of Pediatric Botulinum Toxin Treatments: What Have We Learned from Injection Techniques, Doses, Dilutions, and Recovery of Repeated Injections?

Botulinum toxin type A (BTXA) has been used for over 25 years in the management of pediatric lower and upper limb hypertonia, with the first reports in 1993. The most common indication is the injection of the triceps surae muscle for the correction of spastic equinus gait in children with cerebral palsy. The upper limb injection goals include improvements in function, better positioning of the arm, and facilitating the ease of care. Neurotoxin type A is the most widely used serotype in the pediatric population. After being injected into muscle, the release of acetylcholine at cholinergic nerve endings is blocked, and a temporary denervation and atrophy ensues. Targeting the correct muscle close to the neuromuscular junctions is considered essential and localization techniques have developed over time. However, each technique has its own limitations. The role of BTXA is flexible, but limited by the temporary mode of action as a focal spasticity treatment and the restrictions on the total dose deliverable per visit. As a mode of treatment, repeated BTXA injections are needed. This literature reviewed BTXA injection techniques, doses and dilutions, the recovery of muscles and the impact of repeated injections, with a focus on the pediatric population. Suggestions for future studies are also discussed.

Near-infrared spectroscopy as a tool for in vivo analysis of human muscles

Recent advances in materials and fabrication techniques provided portable, performant, sensing optical spectrometers readily operated by user-friendly cabled or wireless systems. Such systems allow rapid, non-invasive, and not destructive quantitative analysis of human tissues. This proof-of-principle investigation tested whether infrared spectroscopy techniques, currently utilized in a variety of areas, could be applied in living humans to categorize muscles. Using an ASD FieldSpec® 4 Standard-Res Spectroradiometer with a spectral sampling capability of 1.4 nm at 350–1000 nm and 1.1 nm at 1001–2500 nm, we acquired reflectance spectra in visible short-wave infra-red regions (350–2500 nm) from the upper limb muscles (flexors and extensors) of 20 healthy subjects (age 25–89 years, 9 women). Spectra off-line analysis included preliminary preprocessing, Principal Component Analysis, and Partial Least-Squares Discriminant Analysis. Near-infrared (NIR) spectroscopy proved valuable for noninvasive assessment of tissue optical properties in vivo. In addition to the non-invasive detection of tissue oxygenation, NIR spectroscopy provided the spectral signatures (ie, “fingerprints”) of upper limb flexors and extensors, which represent specific, accurate, and reproducible measures of the overall biological status of these muscles. Thus, non-invasive NIR spectroscopy enables more thorough evaluation of the muscular system and optimal monitoring of the effectiveness of therapeutic or rehabilitative interventions.

Anatomical versus functional motor points of selected upper body muscles

INTRODUCTION

In this study we aimed to identify nerve entry points (NEPs) of superficial skeletal muscles obtained by dissection of 20 human cadavers and compared them with motor points (MP) obtained previously by electrical stimulation.

METHODS

The biceps brachii (BB), trapezius (TZ), latissimus dorsi (LD), pectoralis major (Pmaj), and pectoralis minor (Pmin) muscles were dissected from human cadavers. NEP data (mean ± standard deviation) from each muscle were calculated. F-tests with Bonferroni corrections were used to compare NEPs and MPs.

RESULTS

The number of NEPs was 2 in BB, 1 in Pmin, 4 in TZ, and 3 in LD, whereas the total number in Pmaj varied from 3 to 5. NEPs and MPs were statistically equal only in Pmin and in the descending part of TZ.

DISCUSSION

The findings show crucial differences between NEPs and MPs, possibly impacting the effectiveness of several medical treatment strategies. Muscle Nerve 57: 460-465, 2018.

Does the method of botulinum neurotoxin injection for limb spasticity affect outcomes? A systematic review

OBJECTIVE

To systematically review randomized controlled trials of botulinum neurotoxin for limb spasticity to determine whether different injection techniques affect spasticity outcomes.

METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials electronic databases were searched for English language human randomized controlled trials from 1990 to 13 May 2016. Studies were assessed in duplicate for data extraction and risk of bias using the Physiotherapy Evidence Database scale and graded according to Sackett's levels of evidence.

RESULTS

Nine of 347 studies screened met selection criteria. Four categories of botulinum neurotoxin injection techniques were identified: (1) injection localization technique; (2) injection site selection; (3) injectate volume; (4) injection volume and site selection. There is level 1 evidence that: ultrasound, electromyography, and electrostimulation are superior to manual needle placement; endplate injections improve outcomes vs. multisite quadrant injections; motor point injections are equivalent to multisite injections; high volume injections are similar to low volume injections; and high volume injections distant from the endplate are more efficacious than low volumes closer to the endplate.

CONCLUSION

Level 1 evidence exists for differences in treatment outcomes using specific botulinum neurotoxin injection techniques. Findings are based on single studies that require independent replication and further study.

Surface mapping of motor points in biceps brachii muscle

Objective

To localize the site of motor points within human biceps brachii muscles through surface mapping using electrophysiological method.

Method

We recorded the compound muscle action potentials of each lattice of the biceps brachii in 40 healthy subjects. Standardized reference lines were made as the following: 1) a horizontal reference line (elbow crease) and 2) a vertical reference line connecting coracoid process and mid-point of the horizontal reference line. The Compound muscle action potentials were mapped in reference to the standardized reference lines. The locations of motor points were mapped to the skin surface, in the ratio to the length of the vertical and the half of the horizontal reference lines.

Results

The motor point of the short head of biceps was located at 69.0±4.9% distal and 19.1±9.5% medial to the mid-point of horizontal reference line. The location of the motor point of the long head of the biceps was 67.3±4.3% distal and 21.4±8.7% lateral. The motor point of the short head of the biceps was located more medially and distally in the male subjects compared to that in the female (p<0.05).

Conclusion

This study showed electrophysiological motor points of the biceps brachii muscles through surface mapping. This data might improve the clinical efficacy and the feasibility of motor point targeting, when injecting botulinum neurotoxin in biceps brachii.

Effective zone of botulinum toxin a injections in hallux claw toe syndrome: an anatomical study

INTRODUCTION

The aim of this study was to determine the anatomical location of the motor points of the flexor hallucis longus (FHL) and brevis (FHB) muscles for an effective motor point block.

METHODS

Twenty cadavers were used for this study. For the FHL, we identified the line between the medial and lateral epicondyle of the femur and the line joining the prominent point on the surface of the medial malleolus of the tibia and the lateral malleolus of the fibula. For the FHB, we identified the line between the middle-lowest point of the great toe and the middle-lowest point of the sole of the foot.

RESULTS

The dense area of the motor points was located at 40-70% for the FHL and 50-70% for the FHB.

CONCLUSION

An injection area of 50-60% on the reference line for the FHL and FHB is suggested.

[Botulinum toxin in the treatment of adult spasticity. An interdisciplinary German 10-point consensus 2010]

Spasticity is one of the major causes of functional impairment in adults with lesions of the central nervous system. For instance, approximately 30% of post-stroke patients suffer from different degrees of spasticity with possible consecutive impairments. Numerous studies or meta-analyses showed that local injections of botulinum toxin in spastic muscles lead to dose-dependent reduction in muscle tone and improvement of passive movements (e. g. facilitated care), especially following repeated injections.However, country-specific regulations and patient-remote administration in German health care often do not allow adequate provision of this therapy. Thus, the present consensus statement based on the EBM analyses of the published international literature tries to highlight recent advances and the standard in the field of local spasticity treatment, aiming to facilitate communication between the decision makers and German reimbursement institutions in health care. Prior to initiation of BoNT-A injections, patient-oriented goals should be identified in a multiprofessional context to assure realistic goals for this specific treatment and patient expectations. In Germany for the treatment of focal spasticity following stroke three products have been approved: Botox® (Pharm Allergan, Ettlingen), Dysport® (Ipsen Pharma, Ettlingen) and Xeomin® (Merz Pharma, Frankfurt/Main). For all preparations safety has been repeatedly shown. Functional improvements have also been illustrated for selected patients concerning hand/arm function and gait. The dose per muscle and the selection of muscles to be injected have to be individualized according to the patient's symptoms and should be accompanied by modern neurorehabilitative therapies such as redression or repetitive activation of the injected and antagonistic muscles.

A coupled electromechanical model for the excitation-dependent contraction of skeletal muscle

This work deals with the development and implementation of an electromechanical skeletal muscle model. To this end, a recently published hyperelastic constitutive muscle model with transversely isotropic characteristics, see Ehret et al. (2011), has been weakly coupled with Ohm's law describing the electric current. In contrast to the traditional way of active muscle modelling, this model is rooted on a non-additive decomposition of the active and passive components. The performance of the proposed modelling approach is demonstrated by the use of three-dimensional illustrative boundary-value problems that include electromechanical analysis on tissue strips. Further, simulations on the biceps brachii muscle document the applicability of the model to realistic muscle geometries.

Botulinum toxin assessment, intervention and follow-up for paediatric upper limb hypertonicity: international consensus statement

The primary objective of this paper was to evaluate the published evidence of efficacy and safety of botulinum neurotoxin (BoNT) injections in paediatric upper limb hypertonia (PULH). Secondary objectives included the provision of clinical context, based on evidence and expert opinion, in the areas of assessment, child and muscle selection, dosing, and adjunctive treatment. A multidisciplinary panel of authors systematically reviewed, abstracted, and classified relevant literature. Recommendations were based on the American Academy of Neurology (AAN) evidence classification. Following a literature search, 186 potential articles were screened for inclusion, and 15 of these met the criteria and were reviewed. Grade A evidence was found to support the use of BoNT to reach individualized therapeutic goals for PULH. There is grade B evidence (probably effective) for tone reduction following BoNT injections and grade U evidence (inconclusive) for improvement in upper limb (UL) activity and function. BoNT injections were generally found to be safe and well tolerated with the most common side effect identified as a transient decrease in grip strength.

Botulinum toxin dilution and endplate targeting in spasticity: a double-blind controlled study

OBJECTIVE

To determine the effects of botulinum neurotoxin type A (BTX-A) dilution and endplate-targeting in spastic elbow flexors.

DESIGN

Double blind randomized controlled trial; 4-month follow-up after a 160-unit injection of BTX-A into spastic biceps brachii (4 sites). Randomization into: group 1: 100 mouse units (MU)/mL dilution, 0.4cc/site, 4-quadrant injection; group 2: 100MU/mL dilution, 0.4cc/site, 4 sites along endplate band; group 3: 20MU/mL dilution, 2cc/site, 4-quadrant injection (n=7 per group).

SETTING

Institutional tertiary care ambulatory clinic.

PARTICIPANTS

Referred sample of 21 adults with spastic hemiparesis. No participant withdrew due to adverse effects.

INTERVENTION

A 160-unit injection of BTX-A of different dilutions and locations into biceps brachii.

MAIN OUTCOME MEASURES

Primary: agonist and antagonist (cocontraction) mean rectified voltage (MRV) of elbow flexors/extensors during maximal isometric flexion/extension; secondary: maximal voluntary power of elbow flexion/extension; spasticity angle and grade in elbow flexors/extensors (Tardieu Scale); active range of elbow extension/flexion.

RESULTS

BTX-A injection overall reduced agonist flexor MRV (-47.5%, P<0.0001), antagonist flexor MRV (-12%, P=.037), antagonist extensor MRV (-19%, P<.01), flexion maximal voluntary power (-33%, P<.001), elbow flexor spasticity angle (-30%, P<.001) and grade (-17%, P=.03), and increased extension maximal voluntary power (24%, P=.037) and active range of elbow extension (5.5%, 8 degrees , P=.002). Agonist and antagonist flexor MRV reductions in group 3 (-81% and -31%) were greater than in groups 1 and 2, whereas increase in active range of elbow extension was greater in group 2 (10%) than in groups 1 and 3 (P<.05, analysis of covariance [ANCOVA]). Elbow flexor spasticity was significantly reduced in groups 2 and 3 only (P<.05, ANCOVA).

CONCLUSIONS

In spastic biceps, high-volume or endplate-targeted BTX-A injections achieve greater neuromuscular blockade, cocontraction and spasticity reduction, and active range of elbow extension improvement, than low volume, nontargeted injections.

Comparative impact of 2 botulinum toxin injection techniques for elbow flexor hypertonia

OBJECTIVE

To compare 2 techniques of botulinum toxin injection for elbow flexor hypertonia.

DESIGN

Parallel-group, randomized, controlled trial with blinded outcome assessment.

SETTING

Laboratory, tertiary rehabilitation hospital.

PARTICIPANTS

Adults (N=31) with acquired brain injury (21 with traumatic brain injury, 8 with stroke, 2 with hypoxic encephalopathy) provided 36 sets of elbow flexors with Ashworth Scale scores equal to 3.

INTERVENTION

Botulinum toxin type A (BTX-A) was injected with a motor point or a multisite injection technique after obtaining 2 baseline evaluations of the main outcome measures. Motor point technique involved decremental electric stimulation with delivery of 60U of BTX-A (Botox) in 2.4mL or 30U BTX-A in 1.2mL of preservative-free saline at single biceps and brachioradialis motor points, respectively. Distributed injection was performed using electromyographic feedback. Fifteen units in 0.6mL were delivered to each of 4 biceps sites and 2 brachioradialis sites. Total dose (90U) and total injection volume (3.6mL) were identical across groups. Only sites and injection techniques varied. The brachialis was not injected in either group.

MAIN OUTCOME MEASURES

Ashworth Scale, Tardieu catch angle, and root mean square surface electromyographic activity of the biceps, brachialis, and brachioradialis.

RESULTS

Postintervention testing at 3 weeks showed no significant differences between groups (P range, .31-.82 across 3 outcome measures). However, within each group, significant treatment effects were observed on all outcome measures (all P<.01). For the uninjected brachialis muscle, electromyographic reduction was greater for the distributed group.

CONCLUSIONS

In 31 adults with acquired brain injury, single motor point and multisite distributed injections of low-dose, high-volume BTX-A had similar impact. Findings suggest that low-dose, high-volume strategies may have a potential role in reducing drug cost and helping clinicians stay within accepted limits for total body dose in patients with upper motoneuron syndrome requiring many injections.

Botulinum neurotoxin: evolution from poison, to research tool--onto medicinal therapeutic and future pharmaceutical panacea

Botulinum neurotoxin (BoNT), for more than a hundred years, has been a recognized poisonous principle in spoiled food. As its chemical structure became unraveled, and as more knowledge was gained over its mechanism of toxicity, it became clear that BoNT had the potential to act therapeutically as a targeted toxin that could inactivate specific nerve populations, and thus achieve a therapeutic goal. BoNT has evolved over the past 25 years into a viable therapeutic, now being a first line treatment for dystonia, overtly altering the course of progression of this disorder. BoNT is used for hyperhidrosis and gustatory sweating syndrome, alleviation of pain, as a treatment for overactive bladder, achalasia and anal fissure; and it has gained popularity as a cosmetic aid. Many other possible uses are being explored. The greatest potential for BoNT may lie in its being a molecular Trojan Horse - able to carry a specific enzyme or specific drug to the inside of a cancer or other type of cell while bypassing other cells and thereby having little or no ill effect. BoNT's pharmaceutical potential is boundless.

Anterior interosseous nerve conduction study: normative data

Neurophysiological techniques assessing anterior interosseous nerve (AIN) function and employing surface electrode recordings from the flexor pollicis longus (FPL), have been limited by technical difficulties. The aim of this study was to describe a surface electrode recording technique of investigating the AIN by recording compound muscle action potentials (CMAPs) from FPL. CMAP responses exhibited a negative onset, suggesting that they originated from FPL, and this was confirmed by needle recording. Normative data has been established that may prove useful in future studies assessing pathological involvement of the anterior interosseous nerve.