Single Injection Of Botulinum Toxin Research Articles

Duration of bite force reduction following a single injection of botulinum toxin in the masseter muscle bilaterally: A one-year non-randomized trial.

Previous studies concerning the effect of botulinum toxin in masseter muscle have mainly reported effects observed through inspection of facial features or differences in pain levels. One systematic review of studies utilizing objective measurements reported that long-term muscular effect of botulinum neurotoxin injections into masseter muscle was inconclusive. To evaluate the duration of reduced maximal voluntary bite force (MVBF) after botulinum toxin intervention. The intervention group was comprised of individuals seeking aesthetic treatment for masseter reduction (n= 20), the reference group (n= 12) comprised of individuals with no intervention. Intervention through 25 units of Xeomin® (Merz Pharma GmbH & Co KGaA, Frankfurt am Main, Germany) botulinum neurotoxin type A injected into the masseter muscles bilaterally (totalling 50 units). A reference group did not receive any intervention. MVBF was measured in Newtons using a strain gauge meter at the incisors and first molars. MVBF was measured at baseline, at 4 weeks, 3 months, 6 months, and after 1 year. Both groups were similar in terms of bite force, sex and age at baseline. MVBF remained similar compared to baseline in the reference group. At 3 months, a significant reduction at all measurement points was observed in the intervention group; at 6 months, this reduction was no longer significant. A single intervention of 50 units of botulinum neurotoxin results in a reversible MVBF reduction of at least 3months, although a visually discernable reduction may be more long-lasting.

A Single Botulinum Toxin Injection in the Treatment of Strabismus: A Retrospective Analysis of 29 Patients

Objective: To describe the change in angle deviation, treatment effectiveness, overall safety, and cost effectiveness of the use of a single botulinum toxin injection session in the treatment of strabismus.Methods: A retrospective analysis at a tertiary hospital in Amman, Jordan, to identify 29 patients who received a single botulinum toxin injection as a treatment of strabismus between October 2017 and March 2019. The outcome was determined by the improvement of the angle of deviation and avoidance of conventional muscle surgery. The safety profile was determined according to the incidence of adverse effects,such as overcorrection and ptosis. The economic profile included the medical and non-medical costs.Results: The average of the total angles of deviation for the whole group improved in the first assessment visit in the first week post injection from 38.97 to 19.48 prism diopter (PD). However, the deviation started to increase after the first month and continued to increase, reaching 27.93 PD in the sixth month post injection follow up. About five of the 29 patients (17.2%) had a successful outcome (angle of deviation equal to or less than 10 PD) in the sixth month post injection, while around seven of the 29 patients (24.1%) had a partial improvement and 17 of the 29 patients (58.7%) had no improvement. Only two patients (6.8%) developed overcorrection. None of the patients developed ptosis or other adverse effects after injection. The total average cost of treatment, including medical and non-medical costs, was $410. The average medical cost was $305, while the non-medical cost was $105. Conclusion: The use of a single botulinum toxin injection for treating strabismus is an effective, safe, and quick procedure to treat strabismus in some patients, especially those with mild and moderate angles of deviation. However, due to the temporary effect of the drug, it needs to be repeated for some patients and thus may be unsatisfactory in some circumstances.

Time course response after single injection of botulinum toxin to treat spasticity after stroke: Systematic review with pharmacodynamic model-based meta-analysis.

The time-course response after a single injection of botulinum toxin (BoNT) for post-stroke spasticity is debated. We addressed this issue by conducting a systematic review and a pharmacodynamic model-based meta-analysis. We searched Medline, PeDro and Google Scholar databases up to March 2020, selecting randomized controlled trials of post-stroke and traumatic brain injury patients with arm or leg muscle hypertonia, comparing BoNT to placebo, or different BoNT preparations. The main outcome was change in Modified Ashworth Scale (MAS) score. A non-linear mixed effect model was used to estimate maximal toxin and placebo effects (Emax and EPlacebo), the effect disappearance half-life (T1/2off) of BoNT and the doses achieving 50 and 80% of Emax (D50 and D80). The equivalence ratios between different BoNT preparations were calculated from D50 values. Adverse events were recorded. Altogether, 2,236 unique records were screened by 2 independent reviewers: 35 eligible trials including 3011 patients (95% post-stroke) were identified. For all BoNT preparations, the BoNT Emax of -1.11 (95% credible interval -1.31; -0.29) was reached at 5 weeks; the maximal placebo effect was -0.30 (-0.37; -0.22). Both D50 and D80 differed significantly by muscle volume. At D50, the equivalence ratio was significantly higher for abobotulinumtoxinA (3.35) than onabotulinumtoxinA and lower for letibotulinumtoxinA (0.41). T1/2off was longer for abobotulinumtoxinA than for onabotulinumtoxinA and the other preparations (13.1 weeks [95% credible interval 7.7; 19.3] vs 8.6 weeks [7.1; 10.1]). Adverse events were minor, with a weak, but significant, dose-response relation for muscle weakness. This first pharmacodynamic model-based meta-analysis of individuals with stroke revealed that for all BoNT-A preparations, BoNT-A injections to treat spasticity have maximal effect at 5 weeks. The T1/2off was longer for abobotulinumtoxinA than other preparations. Differences between certain BoNT unit scales were also confirmed.

Effectiveness of single botulinum toxin injection for strabismus in children with and without neurological disorders

Effectiveness of single botulinum toxin injection for strabismus in children with and without neurological disorders

Essential Infantile Esotropia: A Course of Treatment From Our Experience.

Background: Essential infantile esotropia (EIE) is the most common type of childhood esotropia. Although its classical approach is surgical, less invasive techniques have been proposed as an adjunct or alternative to traditional surgery. Among them, chemodenervation with botulinum toxin (BT) has been investigated, showing variable and sometimes conflicting results.Objectives: To compare the outcomes of bilateral BT injection and traditional surgery in a pediatric population with EIE in order to optimize and standardize the therapeutic approach. Other purposes are to evaluate whether early intervention may prevent the onset of vertical ocular deviation (which is part of the clinical picture of EIE) and/or influence the development of fine stereopsis, and also to assess changes in refractive status over time among the enrolled population.Methods: A retrospective consecutive cohort study was conducted in 86 children aged 0–48 months who underwent correction of EIE. The primary intervention in naïve subjects was either bilateral BT injection (36 subjects, “BT group”) or strabismus surgery (50 subjects, “surgery group”).Results: Overall, BT chemodenervation (one or two injections) was effective in 13 (36.1%) subjects. With regard to residual deviation angle, the outcomes at least 5 years after the last intervention were overlapping in children receiving initial treatment with either injection or surgery; however, the success rate of primary intervention in the surgery group was higher, and the average number of interventions necessary to achieve orthotropia was smaller. Both early treatment with chemodenervation and surgery at a later age were not found to prevent the onset of vertical ocular deviation, whereas, surprisingly, the percentage of subjects developing fine stereopsis was higher in the surgery group. Finally, with regard to the change in refractive status over time, most of the subjects increased their initial hyperopia, whereas 10% became myopic.Conclusions: Our data suggest that a single bilateral BT injection by age 2 years should be considered as the first-line treatment of EIE without vertical component; whereas, traditional surgery should be considered as the first-line treatment for all other cases and in subjects unresponsive to primary single BT injection.

Differences of a Single Injection of Botulinum Toxin A between Infantile and Nonaccommodative Esotropia

ABSTRACT Purposes To compare the results of a single injection of botulinum toxin A (BTA) between children with infantile esotropia (IET) and nonaccommodative esotropia (NAET) during the first 2 years. Methods Retrospective study that included 23 children with IET and 25 with NAET. At 6 months, 1 and 2 years after treatment, the deviation and stereoacuity were evaluated. Results At 6 months and 1 year after treatment there was no difference in ocular alignment between the two groups (success criteria were achieved in 36.8% in IET group and 60.0% in NAET at 6 months p = .129, and 57.9% in IET group and 68.0% in NAET group at 1 year p = .352). Two years after treatment, there were statistical differences between motor alignment (IET group 21,1% and NAET group 60.0%, p = .007) and stereoacuity (IET group 40% and NAET group 90%, p = .004) between the two groups. Although side-effects affected most children during the first week (in the first week, overcorrection was present in 16 (84.2%) children with IET, and in 19 (76.0%) children with NAET; and ptosis affected 15 (78.9%) children with IET and 17 (68.0%) children with NAET), at 6 months all the effects have disappeared on both groups. Conclusions We recommend BTA as an alternative, but not as definite treatment in IET if the surgeon/parents are not comfortable with an early strabismus surgery; but retreatment or surgery will have to be considered after 1 year. On the contrary, BTA may be a first-line treatment of NAET because it is an easy, safe and has a long-lasting effect.

The Long-term Efficacy of Botulinum Toxin Injection to Treat Retrograde Cricopharyngeus Dysfunction.

ObjectivesTo report the percentage of patients with symptom relief 6 or more months after botulinum toxin injection into the cricopharyngeus muscle for retrograde cricopharyngeus dysfunction (R-CPD).Study DesignRetrospective case series of consecutively treated patients.SettingTertiary care laryngology clinic.Subjects and MethodsA review was performed of the first 200 patients who were diagnosed with R-CPD and treated with botulinum toxin injection into the cricopharyngeus muscle by a single surgeon. The study group was limited to those for whom a minimum of 6 months has elapsed since the injection. Items assessed were efficacy, safety, complications, and duration of benefit.ResultsOf 200 patients treated, (99.5%) gained the ability to burp and 95% experienced relief of the cardinal symptoms of R-CPD: inability to belch, socially awkward gurgling noises, abdominal/chest pressure and bloating, and excessive flatulence. For those who experienced relief, 159 (79.9%) maintained a satisfactory ability to burp after 6 months. Of those who did not maintain the ability, 12 underwent a second injection, 1 patient underwent 3 subsequent injections, and 3 patients underwent partial myotomy. No patients experienced complications of botulinum toxin injection itself, and 4 patients had complications from esophagoscopy or anesthesia.ConclusionIn a case series of 200 patients with retrograde cricopharyngeus dysfunction, 99% experienced relief of the cardinal symptoms and 79.9% experienced lasting relief of their symptoms beyond pharmacologic duration of action after a single injection of botulinum toxin into the cricopharyngeus muscle. Relief can be reestablished in the remainder via additional injection or cricopharyngeus myotomy.

Muscle paralysis induces bone marrow inflammation and predisposition to formation of giant osteoclasts.

Transient muscle paralysis engendered by a single injection of botulinum toxin A (BTxA) rapidly induces profound focal bone resorption within the medullary cavity of adjacent bones. While initially conceived as a model of mechanical disuse, osteoclastic resorption in this model is disproportionately severe compared with the modest gait defect that is created. Preliminary studies of bone marrow following muscle paralysis suggested acute upregulation of inflammatory cytokines, including TNF-α and IL-1. We therefore hypothesized that BTxA-induced muscle paralysis would rapidly alter the inflammatory microenvironment and the osteoclastic potential of bone marrow. We tested this hypothesis by defining the time course of inflammatory cell infiltration, osteoinflammatory cytokine expression, and alteration in osteoclastogenic potential in the tibia bone marrow following transient muscle paralysis of the calf muscles. Our findings identified inflammatory cell infiltration within 24 h of muscle paralysis. By 72 h, osteoclast fusion and pro-osteoclastic inflammatory gene expression were upregulated in tibia bone marrow. These alterations coincided with bone marrow becoming permissive to the formation of osteoclasts of greater size and greater nuclei numbers. Taken together, our data are consistent with the thesis that transient calf muscle paralysis induces acute inflammation within the marrow of the adjacent tibia and that these alterations are temporally consistent with a role in mediating muscle paralysis-induced bone resorption.

Botulinum Toxin Injections Into the Lateral Cricoarytenoid Muscles for Vocal Process Granuloma

Contact granulomas are benign, exophytic inflammatory lesions of the larynx that typically arise on or near the vocal process of the arytenoid cartilage. The most common management options include voice therapy and antireflux pharmacotherapy, intralesional steroid injections, botulinum toxin injections, and surgical excision. In-office Botox injection into the lateral cricoarytenoid (LCA) muscle can be effective even for recurrent granulomas. This is a retrospective chart review and literature review. We reviewed more than 400 charts and included two patients, who underwent in-office injection with botulinum toxin A into LCA muscles bilaterally, after previously failing both conservative and surgical management. Both cases showed significant improvement of the laryngeal granulomas after 6 months and a single botulinum toxin injection. Both cases were initially grade III granuloma that improved to grade I. In-office injection of botulinum toxin A targeting the LCA muscle appears to be a safe and effective treatment modality in refractory laryngeal granuloma.

Recovery of rat muscle size but not function more than 1 year after a single botulinum toxin injection.

Neurotoxin injection is used to treat a wide variety of neuromuscular disorders. The purpose of this study was to measure the functional and structural properties of botulinum toxin-injected adult rat skeletal muscle over nearly the entire lifespan. Ten groups of animals were subjected to either neurotoxin injection [Botox, Type A (BT-A); Allergan, Irvine, California] or saline solution injection. Neurotoxin-injected animals (n = 90) were analyzed at different time-points: 1 week; 1 month; 3 months; 6 months; 12 months; or 18 months. In spite of the recovery of structural features, such as muscle mass and fiber area, dorsiflexion torque production remained significantly depressed by 25%, even at 12 months after neurotoxin injection. The data demonstrate that, after a single BT-A injection, although gross muscle morphology recovered over a 12-month time period, loss of contractile function did not recover. Muscle Nerve 57: 435-441, 2018.

To what extent may Botulinum toxin type A injections be an alternative choice to surgery in infantile esotropia?

Evaluation of a single injection of botulinum toxin A in infantile esotropia as an alternative choice to surgery in a retrospective cases serie. Patients (65 consecutive children aged 9 to 26 months with infantile strabismus) underwent botulinum toxin A injection in both medial recti Botulinum toxin A injection. Clinical datas including measurement of angle of deviation before and after injection. visual acuity, stereoscopy and side effects were observed in a 24 months period of follow-up. Stable satisfactory result (angle equal to or less than 8 dioptres) was obtained in 33 cases (50.7%). Excellent result (-2 to + 4 dioptres) were obtained in 17 children (26%). Additional surgery was required in 32 cases for a residual (albeit smaller angle than the initial deviation) or recurrent deviation and/or DVD (49,2%). Botulinum toxin A reduces the tonic spastic motor component of strabismus and, should additional surgery be required (49% in our series), allows the procedure to be carried out on a smaller angle. A reduction in the maximum angle of deviation is thus achieved sooner, and allows the development of anomalous binocularity in a stable microtropia.

A major improvement in social participation of two children with cerebral palsy by a single botulinum toxin injection.

Elif Yalcin MD, Physical Medicine Rehabilitation Specialist, Sehim Kutlay MD, Physical Medicine Rehabilitation Specialist, Olcay Ilgu MD, Physical Medicine Rehabilitation Specialist, Mufit Akyuz MD, Physical Medicine Rehabilitation Specialist a Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine & Rehabilitation Training and Research Hospital of the Ministry of Health, Ankara, Turkey b Department of Physical Medicine and Rehabilitation, Ankara University of Faculty of Medicine, Ankara, Turkey c Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine & Rehabilitation Training and Research Hospital of the Ministry of Health, Ankara, Turkey

Potential therapeutic effect of intravesical botulinum toxin type A on bladder pain syndrome/interstitial cystitis.

Bladder pain syndrome/interstitial cystitis is characterized by bladder pain associated with urgency, frequency, nocturia, dysuria and sterile urine. Recent studies have shown that these bladder dysfunctions could originate from chronic inflammation or urothelial insult and proceed to a cascade of tissue reactions, which finally ascends to the central nervous system. Pilot studies of intravesical injection of botulinum toxin type A for bladder pain syndrome/interstitial cystitis had been introduced since 2005 with a promising result. Recent evidence suggests that botulinum toxin type A could significantly improve symptoms such as daytime frequency, nocturia, pain, quality of life and bladder capacity in bladder pain syndrome/interstitial cystitis patients. Single injection of botulinum toxin could not achieve long-term successful therapeutic result, and repeat injections could provide a better long-term success rate. However, patients with ulcer type bladder pain syndrome/interstitial cystitis might not gain a benefit from botulinum toxin type A injection. Laboratory evidence showed that botulinum toxin type A for bladder pain syndrome/interstitial cystitis injection could induce peripheral desensitization, reduces bladder chronic inflammation and decreases apoptotic signal molecules in the urothelium. The present article reviewed the recent advances of botulinum toxin type A on bladder pain syndrome/interstitial cystitis.

Botulinum toxin treatment for oropharyngeal dysphagia in patients with stroke

In a previous pilot study, we demonstrated that a single injection of botulinum toxin A (BTX-A) in the cricopharyngeus muscle is effective in patients with neurologic dysphagia with upper esophageal sphincter (UES) opening dysfunction and presence of some pharyngeal contraction (>25mmHg). The aim of this study was to confirm the long-lasting efficacy of this procedure after stroke. We prospectively studied 23 patients with stroke for at least 6months before administration of a BTX-A injection. Baseline diagnosis of UES opening dysfunction and presence of some pharyngeal contraction were assessed by videofluoroscopy (VFS) and esophageal manometry (EM). Clinical and VFS follow-up was made at 3weeks and 3, 6, and 12months postinjection. Eighteen patients (78%) were fed by gastrostomy tube prior to treatment. Videofluoroscopy showed UES relaxation impairment, residue in pyriform sinuses, and aspiration in all cases. After BTX-A, the number of patients with aspiration and pharyngeal residue decreased to 52% and 70%, respectively (p<0.05 for both); residue was severe in only 4%. Esophageal manometry showed a mean pharyngeal amplitude 66.8mmHg (range: 25-120mmHg). We observed a significant improvement in feeding mode during follow-up: after 3months, 70% of patients were eating exclusively by mouth. Lower residual pressure and minor pharyngeal delay time at baseline were all predictive factors for treatment effectiveness. A single injection of BTX-A is efficacious for a period of at least 12months in improving oropharyngeal dysphagia in stroke patients with UES opening dysfunction and some pharyngeal contraction (>25mmHg).

The Efficacy of Botulinum Toxin Treatment for Children with a Persistent Esotropia Following Bilateral Medial Rectus Recessions and Lateral Rectus Resections

Background and PurposeTo report on the outcomes of treating children with a persistent esotropia with an injection of botulinum toxin in a medial rectus muscle.Patients and MethodsThe medical records were reviewed of all children at one institution with a persistent esotropia after bilateral medial rectus recessions and bilateral lateral rectus resections then treated with a botulinum toxin injection.ResultsFive patients with a mean preoperative esotropia of 37Δ (range 25-50Δ) underwent bilateral medial rectus recessions and then bilateral lateral rectus resections. Their residual esotropia (mean of 25Δ; range 18-35Δ) was then treated with a single injection of 3-5 units of botulinum toxin into one medial rectus muscle. The patients were then followed for a mean of 34 months (range 14-79 months). At last follow-up, two patients had an esotropia <10Δ. The other three patients had no long-term improvement in their ocular alignment. Two of these patients then underwent additional strabismus surgery. In both cases, they then developed a consecutive exotropia.ConclusionTreatment with a single injection of botulinum toxin was beneficial in 2 of 5 children. Botulinum toxin treatment alone did not result in a consecutive exotropia in any patients treated.

Temporary management of diplopia with botulinum toxin in multiple ocular motor cranial neuropathies

To report management of diplopia with botulinum toxin injection in traumatic multiple ocular motor cranial neuropathies. Alternate prism and cover measurement of deviation in different positions of gaze, examination of ductions, field of binocular single vision, and complete ocular anterior and posterior segment evaluation were carried out. CT and MRI of the orbit were available. We describe a case of traumatic VI, IV, and mainly superior III cranial nerve palsies, with left hypotropia of 35 prism diopters and esotropia of 45 prism diopters and incapacitating diplopia, due to fracture of the roof and lateral wall of the orbit, extending to the superior orbital fissure, as demonstrated by CT and MRI of the orbit. Severe limitation of abduction, elevation, and depression of the left eye was found. A single botulinum toxin injection in the medial rectus with diffusion to the inferior rectus was effective as a temporary measure for the treatment of diplopia and attainment of a small field of binocular single vision. The patient remained symptom-free for 5 months after injection. Botulinum toxin injection may be useful for the temporary management of diplopia in multiple ocular motor cranial neuropathies.

A Single Injection of Botulinum Toxin Decreases the Margin of Safety of Neurotransmission at Local and Distant Sites

A Single Injection of Botulinum Toxin Decreases the Margin of Safety of Neurotransmission at Local and Distant Sites

A Single Injection of Botulinum Toxin Decreases the Margin of Safety of Neurotransmission at Local and Distant Sites

We tested the hypothesis that a single injection of botulinum toxin not only has local, but also distant effects on muscle function, biochemistry, and pharmacodynamics of atracurium. Botulinum toxin (2.5 U) was injected into the tibialis muscle of anesthetized rats (n = 26). The contralateral side with no injection served to study distant effects. Control animals (n = 25) received a saline injection. Neuromuscular function, pharmacology, and expression of acetylcholine receptors (nAChRs) were evaluated in the tibialis at 0, 4, and 16 days after injection and in comparison with saline- injected controls. On day 4, botulinum toxin caused complete paralysis of the tibialis, while its contralateral side showed a decrease in absolute twitch tension (1.8 N [1.6; 1.9] vs 3.0 N [2.8; 3.1], Newton, P < 0.05). On day 16, muscle weakness was only present on the toxin-injected side where absolute twitch tension was decreased (0.6 N [0.6, 0.7] vs 3.4 N [3.1, 3.7], P < 0.05). Tibialis mass was decreased on the toxin-injected side at day 4 (1.46 mg/g [1.43, 1.48] vs 1.74 mg/g [1.72; 1.75], P < 0.05) and on day 16 (0.78 mg/g [0.76, 0.79] vs 1.73 mg/g [1.69; 1.77], P < 0.05). Effects distant from the site of injection were seen on day 16, when muscle atrophy was also present in the adjacent gastrocnemius and soleus muscles. Normalized to tibialis mass, specific twitch tension (tension/g muscle) was reduced on the contralateral side at day 4 and on the toxin-injected side at day 16 in relation to saline controls. At day 16, an increased sensitivity to atracurium was seen on the toxin-injected side, evidenced as a decreased ED(50) (0.23 mg/kg [0.13, 0.33] vs 0.72 mg/kg [0.63, 0.82], P < 0.05) and a lower infusion rate (38 μL/kg/min [32, 43] vs135 μL/kg/min [126, 144], P < 0.05), together with a reduced plasma concentration requirement of atracurium (0.5 μg/mL [0.4, 0.7] vs 4.5 μg/mL [3.8, 5.2], P < 0.05) to achieve a steady state 50% reduction in baseline (absolute) twitch tension. ED(50) of atracurium was also decreased on the contralateral side at day 16 in relation to saline controls. The nAChRs in the tibialis were increased on the toxin-injected side to 123 fmol/mg [115, 131] vs 28 fmol/mg [25, 29] (P < 0.05) in time-matched saline-injected controls at day 4 and to 378 [341, 413] vs 27 fmol/mg [25, 29] (P < 0.05) at day 16. Botulinum toxin has local and distant effects on muscle. The decrease in specific twitch tension indicates that the muscle atrophy alone cannot explain the functional changes; neuromuscular transmission is also impaired. An increased sensitivity to atracurium on the toxin-injected side, despite up-regulation of nAChRs, seems unique to botulinum toxin.

Laparoscopic extended cardiomyotomy in children: an effective procedure for the treatment of esophageal achalasia

Purpose Achalasia of the esophagus is characterized by aperistalsis and incomplete relaxation of the lower esophageal sphincter in response to swallowing. The objective of the present study is to present the experience of a modified Heller myotomy via a laparoscopic approach for the treatment of children who had this condition. Methods A retrospective review of medical records of all patients who underwent this procedure from 2000 to 2009 was performed. The procedure consisted of an extended esophagomyotomy beginning on the lower part of the lower esophageal sphincter and continuing 5 to 6 cm above on the lower third of the esophagus, and then extended 3 to 4 cm below to the stomach, associated with an anterior 180-degree hemi-fundoplication according to Dor's technique. Results Fifteen patients were included in the study. There were 8 female and 7 male patients. Mean operating time was 190 minutes with no intraoperative complications and 1 conversion to open surgery because of difficulty in dissecting an inflamed distal esophagus. In a mean follow-up period of 32.3 months, 2 patients had recurrence of mild dysphagia that disappeared spontaneously, and 1 required a single botulinum toxin injection with complete resolution of symptoms. Conclusion We conclude that the laparoscopic extended Heller myotomy with Dor fundoplication is a safe and effective method for the treatment for achalasia in the pediatric population even in advanced cases.

Botulinum toxin within the muscle – MRI follow up in children with spastic cerebral palsy supports neurogenic atrophy in healthy muscle one year after a single injection of botulinum toxin

Botulinum toxin is widely used as a therapeutic option to reduce (multi-) focal muscle hypertension as well as for cosmetic indications. Recommendations on reinjection intervals (3-12months) are based on clinical observation and basic science research using animal models. Morphologic long-term alterations following a single injection of botulinum toxin are scarce. With the development of short tau inversion recovery (STIR) sequences Magnetic resonance imaging (MRI) is able to detect neurogenic muscle atrophy over the course of time. The aim of this study was to investigate the neurogenic atrophy induced by a single injection of botulinum toxin in healthy adult muscle and the induced atrophy in primarily altered spastic muscle in children with cerebral palsy (CP).