Systematic reviews and quality assessment of patient-reported outcome measures for physical function in comparative effectiveness studies regarding acute postoperative pain after total knee arthroplasty-Do we need to start all over again?

BACKGROUND AND OBJECTIVE

Recently, a consensus process specified a core outcome set (COS) of domains to be assessed in each comparative effectiveness research and clinical practice related to acute postoperative pain. Physical function (PF) was one of these domains. The aim of this review was to investigate which patient-reported outcome measures (PROMs) are used to assess PF after total knee arthroplasty (TKA) in clinical trials and if they fulfil basic requirements for a COS of PROMs based on their psychometric properties.

METHODS

A systematic review of randomized controlled trials and observational studies based on a search in MEDLINE, EMBASE and CENTRAL was undertaken. PROMs and performance measures were extracted and investigated, including evaluation of psychometric properties of PROMs based on COSMIN recommendations.

RESULTS

From initially 2896 identified records, 479 studies were included in the qualitative synthesis. Only 87 of these trials (18%) assessed PF using PROMs, whereas especially performance outcome measures were used in 470 studies (98%). Application of the 'COSMIN Risk-of-Bias-Box 1' to 13 of the 14 identified PROMs resulted in insufficient content validity of the included PROMs regarding the target population based on the inauguration or development articles.

CONCLUSION

Our data indicate that a patient-centred postoperative assessment of PF in pain-related clinical trials early after TKA is not common, even though patient-reported assessment is widely recommended. In addition, none of the applied PROMs shows content validity based on their inauguration or development articles for the assessment of postoperative pain-related PF after TKA.

SIGNIFICANCE

A systematic search for patient-reported outcome measures assessing postoperative, pain-related physical function after total knee arthroplasty in clinical trials and assessment of their content validity revealed none that fulfilled requirements based on COSMIN recommendations.

"Pseudo"-Secondary Treatment Failure Explained via Disease Progression and Effective Botulinum Toxin Therapy: A Pilot Simulation Study

BACKGROUND

The objective of this study was to provide evidence from a simple simulation. In patients with focal dystonia, an initial good response to botulinum neurotoxin (BoNT) injections followed by a secondary worsening does not necessarily arise from an antibody-induced secondary treatment failure (NAB-STF), but may stem from a "pseudo"-secondary treatment failure (PSEUDO-STF).

METHODS

The simulation of the outcome after BoNT long-term treatment was performed in four steps: 1. The effect of the first single BoNT injection (SI curve) was displayed as a 12-point graph, corresponding to the mean improvement from weeks 1 to 12. 2. The remaining severity of the dystonia during the nth injection cycle was calculated by subtracting the SI curve (weighted by the outcome after n - 1 cycles) from the outcome after week 12 of the (n - 1)th cycle. 3. A graph was chosen (the PRO curve), which represents the progression of the severity of the underlying disease during BoNT therapy. 4. The interaction between the outcome during the nth BoNT cycle and the PRO curve was determined.

RESULTS

When the long-term outcome after n cycles of BoNT injections (applied every 3 months) was simulated as an interactive process, subtracting the effect of the first cycle (weighted by the outcome after n - 1 cycles) and adding the progression of the disease, an initial good improvement followed by secondary worsening results. This long-term outcome depends on the steepness of the progression and the duration of action of the first injection cycle. We termed this response behavior a "pseudo"-secondary treatment failure, as it can be compensated via a dose increase.

CONCLUSION

A secondary worsening following an initial good response in BoNT therapy of focal dystonia might not necessarily indicate neutralizing antibody induction but could stem from a "PSEUDO"-STF (a combination of good response behavior and progression of the underlying disease). Thus, an adequate dose adaptation must be conducted before diagnosing a secondary treatment failure in the strict sense.

Differences in the Time Course of Recovery from Brain and Liver Dysfunction in Conventional Long-Term Treatment of Wilson Disease

BACKGROUND

The aim of this study was to demonstrate that both neurological and hepatic symptoms respond to copper chelation therapy in Wilson disease (WD). However, the time course of their recovery is different.

METHODS

Eighteen patients with neurological WD from a single specialized center who had been listed for liver transplantation during the last ten years and two newly diagnosed homozygous twins were recruited for this retrospective study. The mean duration of conventional treatment was 7.3 years (range: 0.25 to 36.2 years). A custom Wilson disease score with seven motor items, three non-motor items, and 33 biochemical parameters of the blood and urine, as well as the MELD score, was determined at various checkup visits during treatment. These data were extracted from the charts of the patients.

RESULTS

Treatment was initiated with severity-dependent doses (≥900 mg) of D-penicillamine (DPA) or triethylene-tetramin-dihydrochloride (TRIEN). The motor score improved in 10 and remained constant in 8 patients. Worsening of neurological symptoms was observed only in two patients who developed comorbidities (myasthenia gravis or hemispheric stroke). The neurological symptoms continuously improved over the years until the majority of patients became only mildly affected. In contrast to this slow recovery of the neurological symptoms, the MELD score and liver enzymes had already started to improve after 1 month and rapidly improved over the next 6 months in 19 patients. The cholinesterase levels continued to increase significantly (p < 0.0074) even further. One patient whose MELD score indicated further progression of liver disease received an orthotopic liver transplantation 3 months after the diagnosis of WD and the onset of DPA treatment.

CONCLUSIONS

Neurological and hepatic symptoms both respond to copper chelation therapy. For patients with acute liver failure, the first 4 months are critical. This is the time span in which patients have to wait either for a donor organ or until significant improvement has occurred under conventional therapy. For patients with severe neurological symptoms, it is important that they are treated with fairly high doses over several years.

No Secondary Treatment Failure during Incobotulinumtoxin-A Long-Term Treatment Demonstrated by the Drawing of Disease Severity

The aim of this study was to detect clinical hints regarding the development of secondary treatment failure (STF) in patients with focal dystonia who were exclusively treated with incobotulinumtoxin/A (incoBoNT/A). In total, 33 outpatients (26 with idiopathic cervical dystonia, 4 with Meige syndrome and 3 with other cranial dystonia) who were treated with repeated injections of incoBoNT/A for a mean period of 6.4 years without interruptions were recruited to draw the course of their disease severity (CoD) from the onset of symptoms to the onset of BoNT therapy (CoDB graph) and from the onset of BoNT therapy to recruitment (CoDA graph). At the time of recruitment, the patients assessed the change in severity as a percentage of the severity at the onset of BoNT therapy. Blood samples were taken to test the presence of neutralizing antibodies (NABs) using the mouse hemidiaphragm assay (MHDA). Patients reported an improvement of about 70% with respect to the mean. None of the patients tested positive for MHDA. Three different types of CoDB and three different types of CoDA graphs could be distinguished. The patients with different CoDB graphs reported different long-term outcomes, but there was no significant difference in long-term outcomes between patients with different CoDA graphs. None of the patients produced a CoDA graph with an initial improvement and a secondary worsening as a hint for the development of STF. A primary non-response was not observed in any of the patients. During long-term treatment with BoNT/A, NABs and/or STF may develop. However, in the present study on patients with incoBoNT/A long-term monotherapy, no hints for the development of NABs or STF could be detected, underlining the low antigenicity of incoBoNT/A.

Lessons about Botulinum Toxin A Therapy from Cervical Dystonia Patients Drawing the Course of Disease: A Pilot Study

AIM OF THE STUDY

To compare the course of severity of cervical dystonia (CD) before and after long-term botulinum toxin (BoNT) therapy to detect indicators for a good or poor clinical outcome.

PATIENTS AND METHODS

A total of 74 outpatients with idiopathic CD who were continuously treated with BoNT and who had received at least three injections were consecutively recruited. Patients had to draw the course of severity of CD from the onset of symptoms until the onset of BoNT therapy (CoDB graph), and from the onset of BoNT therapy until the day of recruitment (CoDA graph) when they received their last BoNT injection. Mean duration of treatment was 9.6 years. Three main types of CoDB and four main types of CoDA graphs could be distinguished. The demographic and treatment-related data of the patients were extracted from the patients' charts.

RESULTS

The best outcome was observed in those patients who had experienced a clear, rapid response in the beginning. These patients had been treated with the lowest doses and with a low number of BoNT preparation switches. The worst outcome was observed in those 17 patients who had drawn a good initial improvement, followed by a secondary worsening. These secondary nonresponders had been treated with the highest initial and actual doses and with frequent BoNT preparation switches. A total of 12 patients were primary nonresponders and did not experience any improvement at all. No relation between the CoDB and CoDA graphs could be detected. Primary and secondary nonresponses were observed for all three CoDB types. The use of initial high doses as a relevant risk factor for the later development of a secondary nonresponse was confirmed.

CONCLUSIONS

Patients' drawings of their course of disease severity helps to easily detect "difficult to treat" primary and secondary nonresponders to BoNT on the one hand, but also to detect "golden responders" on the other hand.

Pseudocholinesterase as a Biomarker for Untreated Wilson's Disease

The aim of this study was to demonstrate that pseudocholinesterase (CHE) serum level is a useful diagnostic biomarker for untreated Wilson's disease (WD). Between 2013 and 2019, about 75 patients were referred to the outpatient department of the University of Düsseldorf with suspected Wilson's disease. In 31 patients with suspected Wilson's disease (WD-SUS-group), WD was excluded by means of investigations other than analysis of blood and urine. A total of 27 parameters of blood and urine in these 31 patients were compared to those of 20 de novo patients with manifest WD (WD-DEF-group), which parameter showed the highest significance level of difference between the WD-DEF-group and the WD-SUS-group. Thereafter, receiver operating characteristics (ROC-curves) were analyzed to evaluate which parameter showed the largest area under the curve (AUC) to detect WD. Finally, a logistic regression analysis was performed to analyze which combination of parameters allowed the best classification of the 51 patients either into the WD-DEF-group or into the WD-SUS-group. CHE showed the highest significance level for a difference between the WD-DEF- and WD-SUS-group, had the highest AUC, and, in combination with ceruloplasmin, allowed 100% correct classification. Without CHE, no other combination of parameters reached this level of correct classification. After the initiation of treatment, which regularly results in an improvement in CHE, the high diagnostic accuracy of this biomarker was lost. Cholinesterase turns out to be an excellent biomarker for differentiation between untreated de novo patients with manifest WD and heterozygotic gene carriers.

Cholinesterase Deficiency Syndrome-A Pitfall in the Use of Butyrylcholinesterase as a Biomarker for Wilson's Disease

A family is described as having two recessively inherited metabolic diseases and three differently affected children. During the explantation of a drain tube grommet under general anesthesia, a prolonged resuscitation and wake-up period occurred in the key case when he was 8 years old. This led to a family screening for butyrylcholinesterase deficiency, which was confirmed not only in the key case but also in his 5-year-old sister; it was not confirmed in his 10-year-old brother. However, the key case not only had reduced serum levels of BCHE, but also elevated liver enzyme levels, which are atypical for BCHE deficiency. After the exclusion of viral and autoimmune hepatitis, Wilson’s disease (WD) was eventually diagnosed and also confirmed in his elder brother, but not in his sister. This family is presented to highlight an extremely rare WD-patient in whom a low serum level of BCHE did not occur because of WD but because of BCHE deficiency.

The complex relationship between antibody titers and clinical outcome in botulinum toxin type A long-term treated patients with cervical dystonia

Background

Repeated injections with abo- or onabotulinumtoxin type A (aboBoNT/A, onaBoNT/A) may lead to induction of neutralizing antibodies (NABs) and/or a secondary treatment failure (STF). The relation between NABs and STF is still unclear.

Aim of the study

To demonstrate that a significant improvement can be observed in patients with STF after abo- or onaBoNT/A-treatment when switched to incobotulinumtoxin type A (incoBoNT/A) and that in NAB-positive patients without STF abo- or onaBoNT/A-treatment can be continued without significant worsening.

Methods

Paralysis times (PT) of the mouse hemidiaphragm assay (MHDA) and clinical outcome (TSUI-score) was analyzed in 60 patients with cervical dystonia (CD) and STF after abo- or onaBoNT/A-treatment (STF-group) who were switched to incobotulinumtoxin type A (incoBoNT/A). These data were compared to those of 34 patients who were exclusively treated with incoBoNT/A (INCO-group). Furthermore, PTs and TSUI-scores were followed up over 7 years in 9 patients with NABs but without STF who were switched to inco-BoNT/A (SWI-group) and 9 other patients with NABs who remained on their previous BoNT/A preparation (NO-SWI-group).

Results

In the STF-group, a significant improvement of TSUI-scores could be detected after switch to incoBoNT/A. This improvement was less pronounced than in the INCO-group. There was no significant difference in long-term outcome between the SWI- and NO-SWI-group.

Conclusion

The best strategy is to avoid the induction of NABs. A switch to incoBoNT/A may lead to improvement in patients with STF. However, in some patients with NABs without STF, BoNT/A-treatment can be continued without significant worsening.

Analysis of Single-Leg Hopping in Long-Term Treated Patients with Neurological Wilson’s Disease: A Controlled Pilot Study

Background and Objectives: In long-term treated patients with neurological Wilson’s disease, the ability to perform single-leg hopping was analyzed to quantify motor deficits. Materials and Methods: Twenty-nine long-term treated Wilson patients had to stand on one leg for at least 3 s and then perform at least five consecutive hops on this leg. Ground reaction forces and temporal patterns of hopping were recorded using an Infotronic® walking system, which consists of soft tissue shoes with a solid, but flexible plate containing eight force transducers allowing measurement of ground reaction forces (GRF) and temporal patterns of foot ground contact. Parameters of hopping were correlated with clinical scores and parameters of copper metabolism and liver enzymes. Patients’ hopping data were compared with those of an age- and sex-matched control group. Results: Five severely affected Wilson patients were unable to hop. Time to the peak was significantly (p < 0.03) shorter in the remaining 24 patients compared to controls, but there was no difference in hopping frequency, the amplitude of ground forces and duration of foot contact. Twelve patients produced a second, sharp, initial “impact” force peak during ground contact in addition to the usual “active” force peak. Variability of the amplitude of the “active” peak was significantly inversely correlated with urinary copper elimination. Conclusions: The majority of long-term treated patients with neurological Wilson’s disease was able to perform single-leg hopping. The presence of a sharp initial “impact” peak in the GRF-curves of hopping may indicate a mild deficit of limb/trunk coordination and subclinical cerebellar impairment.

Analysis of Running in Wilson's Disease

Aim of the study was to analyze the ability of long-term treated patients with Wilson’s disease (WD) to run a distance of 40 m. 30 WD-patients from a single center were consecutively recruited. All patients were able to walk a distance of 40 m without walking aids. Vertical ground reaction forces (GRF-curves) were analyzed by means of an Infotronic^® gait analysis system (CDG^®) and correlated with clinical and laboratory findings. Results of the WD-patients were compared to those of an age-and sex-matched control group. 25 of the 30 WD-patients were able to run. Patients being unable to run had a significantly (p < 0.03) higher non-motor score. In comparison to the controls speed of running was significantly (p < 0.02) reduced in WD-patients. Their duration of foot contact on the ground lasted significantly (p < 0.05) longer. Running was more irregular in WD and the variability of times to peak of the GRF-curves was significantly (p < 0.05) increased. All running parameters extracted from the GRF-curves of the CDG^® did not correlate with severity of WD. Cadence of running was significantly (p < 0.03) negatively correlated with serum liver enzyme levels. Running appears to be rather unimpaired in long-term treated WD, only 16% of the 30 WD-patients were unable to run. This knowledge is highly relevant for the patient management, but because of the missing correlation with severity of WD, analysis of running is of minor importance for monitoring WD-therapy.

Mildly Impaired Foot Control in Long-Term Treated Patients with Wilson's Disease

Abnormal gait is a common initial symptom of Wilson's disease, which responds well to therapy, but has not been analyzed in detail so far. In a pilot study, a mild gait disturbance could be detected in long-term treated Wilson patients. The question still is what the underlying functional deficit of this gait disturbance is and how this functional deficit correlates with further clinical and laboratory findings. In 30 long-term treated Wilson patients, the vertical component of foot ground reaction forces (GRF-curves) was analyzed during free walking without aid at the preferred gait speed over a distance of 40 m. An Infotronic^® gait analysis system, consisting of soft tissue shoes with solid, but flexible plates containing eight force transducers, was used to record the pressure of the feet on the floor. Parameters of the GRF-curves were correlated with clinical scores as well as laboratory findings. The results of Wilson patients were compared to those of an age- and sex-matched control group. In 24 out of 30 Wilson patients and all controls, two peaks could be distinguished: the first "heel-on" and the second "push-off" peak. The heights of these peaks above the midstance valley were significantly reduced in the patients (p < 0.05). The time differences between peaks 1 or 2 and midstance valley were significantly negatively correlated with the total impairment score (p < 0.05). Gait speed was significantly correlated with the height of the "push-off" peak above the midstance valley (p < 0.045). The GRF-curves of free walking, long-term treated patients with Wilson's disease showed a reduced "push-off" peak as an underlying deficit to push the center of mass of the body to the contralateral side with the forefoot, explaining the reduction in gait speed during walking.

Continuous Increase of Efficacy under Repetitive Injections of Botulinum Toxin Type/A beyond the First Treatment for Adult Spastic Foot Drop

The objective of this study was to quantify the increase in efficacy during the first four cycles of treatment with botulinum toxin type/A (BoNT/A) in 24 free-walking BoNT/A naïve adult patients with post-stroke hemispasticity and spastic foot drop. Patients were followed over 390 days and received five injections of 800 U aboBoNT/A every three months. Patients assessed the treatment effect at eight visits using a global assessment scale, physicians scored the muscle tone at the ankle joint, measured active and passive ranges of motion (aRoMs, pRoMs) at the knee and ankle joint and determined the distance patients succeeded to walk during a minute. Patients' assessments significantly (p < 0.006) increased with time and significantly correlated with all parameters measured. The best correlation (r = 0.927; p < 0.0001) was found with the sum of the aRoMs of knee and ankle joint. After one year of treatment outcome measures were better than and significantly correlated with the peak effect of the first injection. This correlation was higher for pRoMs (r = 0.855; p < 0.00001) compared to aRoMs (r = 0.567; p < 0.009). When BoNT/A treatment of the spastic foot in chronic hemispasticity is performed regularly every three months for at least one year, patients will experience a significant increase of benefit beyond the first treatment, but have to learn how to adapt to and use the new degree of freedom induced by the injections.

Enhanced Effect of Botulinum Toxin A Injections into the Extensor Digitorum Brevis Muscle after Local Mechanical Leg Vibration: A Case Report

Background: The aim of this study was to demonstrate an increase in muscle action potentials and an enhancement of the efficacy of botulinum toxin (BoNT) after mechanical leg vibration. Methods: A 53-year-old healthy male volunteer underwent vibration ergometry training (VET) every morning and every evening for 10 min for 14 days. Compound muscle action potential (CMAP) of the right (R) and left (L) extensor digitorum brevis (EDB) muscle was analyzed by supramaximal peroneal nerve stimulation before and after VET 12 times during the 14 days. Thereafter, VET was stopped and 20 U incobotulinumtoxin (incoBoNT/A) were injected into the right EDB. During the following 10 days, CMAP of both EDBs was tested 12 times. Results: Under VET, the CMAP of both EDBs significantly increased (L: p < 0.01; R: p < 0.01). During the first 14 days, CMAP of the left EDB before VET was significantly (<0.008) lower than 20 min later after VET. This was not the case for the better trained right EDB. After day 14, CMAP of the untreated left EDB further increased for 6 days and then decreased again. In the right EDB, BoNT-treated EDB CMAP rapidly and highly significantly (p < 0.0001) decreased during the first 48 h by about 90%, from a level of about 14 mV down to a plateau of around 1.5 mV. Conclusion: Local mechanical leg vibration has a short- and long-term training effect. Compared to other studies analyzing the reduction in EDB CMAPs after BoNT injections, the reduction of EDB CMAPs in the present study observed after combined application of BoNT and VET was much faster and more pronounced.

Comparing soleus injections and gastrocnemius injections of botulinum toxin for treating adult spastic foot drop: a monocentric observational study

Objective

Outcome differences between selective abobotulinumtoxin type A (aboBoNT/A) injections into the soleus (SOL) and gastrocnemius (GAS) muscles were investigated in post-stroke patients with spastic foot drop.

Methods

A monocentric observational study was conducted at a university hospital botulinum toxin clinic including 24 free-walking adult, botulinum toxin-naive patients with post-stroke hemiplegia. AboBoNT/A (800 MU in 4 mL saline) was injected into the SOL or GAS muscle under electromyographic guidance. After 30 days post-injection, the effect of aboBoNT/A injection was assessed by patients. The treating physician scored spasticity and measured angles at the knee and ankle joint and gait speed.

Results

After 30 days, significant improvements of subjective and objective outcome measures were observed. No significant difference was observed in the modified Ashworth scale, gait speed, ankle and knee angles, or their angle combinations between the SOL and GAS groups. Tendencies toward greater active range of motion (RoM) improvement in the SOL group and passive RoM improvement in the GAS group were observed. The difference between active and passive ankle extensions plus knee flexions was significantly larger in the SOL group.

Conclusions

Selective 800 MU aboBoNT/A injections into the SOL or GAS muscle were effective but without relevant clinical difference.

Clinical Improvement After Treatment With IncobotulinumtoxinA (XEOMIN®) in Patients With Cervical Dystonia Resistant to Botulinum Toxin Preparations Containing Complexing Proteins

This study investigated the clinical long-term effect of incobotulinumtoxinA (incoBoNT/A) in 33 cervical dystonia (CD) patients who had developed partial secondary therapy failure (PSTF) under previous long-term botulinum toxin (BoNT) treatment. Patients were treated four times every 12 weeks with incoBoNT/A injections. Physicians assessed treatment efficacy using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) at the baseline visit, week 12 and 48. Patients rated quality of life of CD with the Craniocervical Dystonia Questionnaire (CDQ-24). Titres of neutralizing antibodies(NAB) were determined at start of the study and after 48 weeks. All patients had experienced significant and progressive worsening of symptoms in the last 6 months of previous BoNT treatment. Repeated incoBoNT/A injections resulted in a significant reduction in mean TWSTRS at week 12 and 48. Patients' rating of quality of life was highly correlated with TWSTRS but did not change significantly over 48 weeks. During the 48 weeks -period of incoBoNT/A treatment NAB titres decreased in 32.2%, did not change in 45.2%, and only increased in 22.6% of the patients. Thus, repeated treatment with the low dose of 200 MU incoBoNT/A over 48 weeks provided a beneficial clinical long-term effect in PSTF and did not booster titres of NAB.

The Impact of SARS-CoV-2 Pandemic Lockdown on a Botulinum Toxin Outpatient Clinic in Germany

Botulinum neurotoxin type A (BoNT/A) injections have to be administered repeatedly to achieve a rather stable, high level of improvement. This study aimed to take a look at changes in the daily routine of a BoNT/A outpatient clinic due to the SARS-CoV-2 pandemic lockdown, analyze the impact of SARS-CoV-2-induced re-injection delay on outcomes in patients with cervical dystonia (CD) (n = 36) and four other disease entities (n = 58), and study the influence of covariables, including previous injections and doses. For the present observational study, the first 100 patients who were scheduled to have an appointment between April 20 and May 18 during the partial lockdown and also had been treated regularly before the lockdown were recruited. Clinical and demographical characteristics and treatment-related data from the previous visits were extracted from charts. Time delay, symptom severity assessment, and TSUI score (if applicable) were gathered at the first coronavirus pandemic lockdown emergency visit for each patient. Of the 94 patients who could come to the clinic, 48 reported a delay and 44 reported worsening during the delay. Delays ranged from 1 to 63 days, the mean delay was 23 days, and the mean worsening was 26% compared to the previous visit. A significant correlation was found between the duration of the delay and the patient's rating of worsening (PwP). In CD patients, the physician´s rating of CD worsening by the TSUI score (ATUSI-PTSUI) was significantly correlated with general worsening (DwP) and the TSUI at the last visit (PTSUI). A small delay of a few weeks led to a similar worsening of symptoms in CD and all other disease entities and to relapse on a higher level of severity. This relapse can only be compensated by continuous treatment up to at least 1 year until patients reach the same level of treatment efficacy as that before the SARS-CoV-2 pandemic.

The impact of the initial severity on later outcome: retrospective analysis of a large cohort of botulinum toxin naïve patients with idiopathic cervical dystonia

BACKGROUND

The aim of study was to demonstrate that the first three injections of botulinum neurotoxin type A (BoNT/A) appear to be less effective in botulinum toxin naïve patients with idiopathic cervical dystonia (CD) with mild symptoms and low severity scores (TSUI-scores) at onset of BoNT/A-therapy compared to patients with full-blown CD and high initial TSUI-scores.

METHODS

In 337 patients with CD who started BoNT/A-therapy in the BoNT-outpatient clinic of the university hospital in Düsseldorf during the last 12 years, demographical and treatment-related data as well as outcome measures (TSUI-scores) of the first four visits were extracted from the treatment ACCESS data bank.

RESULTS

Distribution of the severity of CD scored using the TSUI-score significantly changed with the first three injections. In patients with a high baseline severity (TSUI-score > 10), mean TSUI-score continuously decreased (p < 0.001), whereas in patients with a low initial severity (TSUI-score < 6), mean TSUI-score increased (p < 0.001) during the first three injection cycles. Individual responses varied between 100% improvement, no response at all, and even worsening. Improvement of CD at the end of an injection cycle was observed in less than 25% in the mildly affected patients, but in more than 80% in the more severely affected patients.

CONCLUSION

Clinical response to the first three BoNT/A-injections in severely affected de novo CD-patients is different from the response to BoNT/A in mildly affected de novo CD-patients. This has implications for further scientific studies and the patient management of mildly affected de novo patients with cervical dystonia.

COVID-19 related muscle denervation atrophy

COVID-19 has presented with a variety of manifestations including peripheral neurological symptoms. The most commonly associated peripheral neuropathies described with COVID-19 are Guillain-Barre syndrome and its variants as well as critical illness polyneuropathy. We report in this paper the distinct MRI findings of an unusual case of peripheral neuropathy associated with COVID-19. These findings are similar to those seen in Guillain-Barre syndrome or one of its variants, although differing from the classic condition in certain key clinical and radiological features.

Clinical Implications of Difference in Antigenicity of Different Botulinum Neurotoxin Type A Preparations: Clinical Take-Home Messages from Our Research Pool and Literature

The three different botulinum toxin type A (BoNT/A) preparations being licensed in Europe and the U.S. differ in protein content, which seems to be a major factor influencing the antigenicity of BoNT/A. In the present study, several arguments out of our research pool were collected to demonstrate that the clinical response and antigenicity were different for the three BoNT/A preparations: some results of (1) a cross-sectional study on clinical outcome and antibody formation of 212 patients with cervical dystonia (CD) being treated between 2 and 22 years; 2) another cross-sectional study on the clinical aspects and neutralizing antibody (NAB) induction of 63 patients having developed partial secondary treatment under abobotulinum (aboBoNT/A) onabotulinumtoxin (onaBoNT/A) who were switched to incobotulinumtoxin (incoBoNT/A) in comparison to 32 patients being exclusively treated with incoBoNT/A. These results imply that (1) the presence of NAB cannot be concluded from the course of treatment, that (2) an increase in the dose and variability of outcome with treatment duration indicates the ongoing induction of NABs over time, that (3) the higher protein load of BoNT/A goes along with a higher incidence and prevalence of NAB induction and that (4) the best response to a BoNT/A is also dependent on the protein load of the preparation.

Effective long-term treatment with incobotulinumtoxin (Xeomin®) without neutralizing antibody induction: a monocentric, cross-sectional study

Background

Among the spectrum of licensed botulinum neurotoxin preparations incobotulinumtoxin (incoBoNT/A; Xeomin®) is the only one which does not contain complex proteins. Therefore, incoBoNT/A has been suggested to have a low antigenicity, but precise estimations on incidence and prevalence of neutralizing antibody formation during long-term treatment are outstanding so far.

Methods

For the present cross-sectional study, 59 patients having exclusively been treated with incoBoNT/A (mono group) and 32 patients having been treated with other BoNT/A preparations less than nine times and who were then switched to at least 14 sessions of incoBoNT/A treatment (switch group) were recruited from one botulinum toxin outpatient clinic. Side effects and doses were extracted from the charts, and the efficacy of treatment was assessed by the patients using a visual analogue scale (0–100). The prevalence of neutralizing antibodies was tested by means of the mouse hemi-diaphragm assay (MHDA).

Findings

None of the patients in the mono and only two in the switch group had a positive MHDA-test. Across all indications and patients, mean improvement exceeded 67%. Improvement did not depend on age at onset, sex, change of dose or duration of treatment, but on disease entity. In patients with cervical dystonia, improvement was about the same in the mono and switch subgroup, but the last dose was different.

Conclusions

The present study confirms the low antigenicity of incoBoNT/A, which has immediate consequences for patient management, and the use of higher doses and shorter durations of reinjection intervals in botulinum toxin therapy.

Clinical relevance of neutralizing antibodies in botulinum toxin long-term treated still-responding patients with cervical dystonia

Background:

The aim of the study was to test the clinical relevance of neutralizing antibodies (NABs) in patients with cervical dystonia (CD) still responding to repeat injections with botulinum toxin type A (BoNT/A).

Methods:

Enzyme-linked immunosorbent assay (ELISA)-test evidence from a cross-sectional study on 221 CD-patients with treatment durations of between 2 and 21 years and still responding to repeat BoNT/A-injections showed the presence of antibodies against BoNT/A in 39 patients. A mouse hemi-diaphragm (MHDA) confirmation test was performed in these 39 ELISA-positive patients, and demographic (age, sex, age at onset of CD) and treatment-related (duration of treatment, mean dose of the last 10 injections, TSUI-score, patient’s subjective scoring of the treatment effect, patient’s scoring of quality of life by means of the CDQ24-questionnaire) data from these 39 patients were compared with data from ELISA-negative patients. Paralysis time, the MHDA outcome measure, was correlated with clinical data.

Results:

The ELISA-positive CD-patients had significantly higher TSUI-scores (p < 0.015), and had been treated for significant longer (p < 0.022) and with significantly higher doses (p < 0.001). Patient’s rating of BoNT/A-treatment effect and quality of life tended to be worse in ELISA-positive compared with ELISA-negative patients. The paralysis time of ELISA-positive patients was significantly correlated with the mean dose of the last 10 injections (p < 0.027) and the pain subscore of the CDQ24 (p < 0.012).

Conclusions:

Presence of NABs is clinically relevant in CD, leading to a significantly worse head position, therapy with significantly higher BoNT/A doses, and a correlation between the CDQ24 pain-subscore and antibody titers.

Mild gait impairment in long-term treated patients with neurological Wilson's disease

BACKGROUND

Abnormal gait is a frequently observed initial symptom of Wilson's disease (WD), which responds well to therapy, but has not been analyzed quantitatively so far. The question therefore is whether abnormalities can be detected by simple quantitative gait measurements in long-term treated Wilson-patients and whether these have a relation to clinical and laboratory findings.

METHODS

In 30 long-term treated Wilson-patients, walking without aid at the preferred gait speed over a distance of 40 meters was analyzed. An Infotronic® gait analysis system which consists of soft tissue shoes with two solid, but flexible plates each containing 8 force transducers was used to record the vertical component of the ground forces and the temporal patterns of foot ground contact. Gait parameters were correlated with clinical scores as well as laboratory findings. Results of Wilson-patients were compared to those of an age- and sex-matched control group.

RESULTS

Wilson-patients walked significantly (P<0.001) slower than normal subjects with equal step length, but lower cadence (P<0.001). Gait speed was negatively correlated with severity of neurological symptoms (r=-0.547; P<0.001) and positively with copper concentration in the 24 h urine (r=0.415; P<0.003). A negative correlation was also found between serum levels of liver enzymes and cadence (r=-0.515; P<0.001). Time normalized temporal patterns of walking were normal.

CONCLUSIONS

The temporal pattern of gait is normal in WD. A compliance dependent reduction of gait speed and cadence underline the necessity of careful long-term therapy monitoring in WD.

High prevalence of neutralizing antibodies after long-term botulinum neurotoxin therapy

Objective

To investigate the prevalence of neutralizing antibodies (NAbs) against botulinum neurotoxin type A (BoNT/A) during long-term BoNT/A treatment in different neurologic indications.

Methods

In this monocentric, observational cross-sectional study, 596 outpatients treated with BoNT/A for different indications were tested for BoNT/A binding antibodies by ELISA. Positive samples were investigated for NAbs with the mouse hemidiaphragm test. The prevalence of NAbs was analyzed for different indications: facial hemispasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. Besides the rate of NAb-positive patients overall and per patient subgroup, a Kaplan-Meier analysis of the probability of remaining NAb negative with duration of treatment is provided, and a stepwise binary logistic regression analysis is performed to identify factors significantly contributing to the induction of NAbs.

Results

Overall, 83 of 596 patients (13.9%) had measurable NAbs. The probability of developing NAbs increased with the single and cumulative dose of treatment and was influenced by the BoNT/A formulation, while all other factors analyzed, including disease entity and treatment duration, had no additional influence.

Conclusions

We present the largest study to date of the prevalence of BoNT/A NAbs in a large unbiased cohort of patients including the relevant neurologic indications. Repeated injections of BoNT/A inevitably bear the risk of developing NAbs. However, in addition to avoiding booster injections and providing short intervals between injections, reducing the individual injected doses may diminish the risk of NAb induction independently of the indication for which BoNT/A is used.