Medicine, Faculty of
Non UBC
Medicine, Department of
DSpace
Lagnau, Philippe
Lo, Alto
Sandarage, Ryan
Alter, Katharine
Picelli, Alessandro
Wissel, Jorg
Verduzco-Gutierrez, Monica
Suputtitada, Areerat
Munin, Michael C.
Carda, Stefano
Khan, Omar
Koçer, Serdar
Reebye, Rajiv
Ultrasound (US)-guided botulinum neurotoxin (BoNT) injections are becoming a mainstay in the treatment of muscle spasticity in upper motor neuron syndromes. As a result, there has been a commensurate increase in US-guided BoNT injection for spasticity training courses. However, many of these courses do not emphasize the importance of ergonomics. This paper aims to highlight the importance of ultrasound ergonomics and presents ergonomic recommendations to optimize US-guided BoNT injection techniques in spasticity management. Expert consensus opinion of 11 physicians (4 different continents; representing 8 countries, with an average of 12.6 years of practice using US guidance for BoNT chemodenervation (range 3 to 22 years)). A search using PubMed, College of Physicians and Surgeons of British Columbia database, EMbase was conducted and found no publications relating the importance of ergonomics in US-guided chemodenervation. Therefore, recommendations and consensus discussions were generated from the distribution of a 20-question survey to a panel of 11 ultrasound experts. All 11 surveyed physicians considered ergonomics to be important in reducing physician injury. There was complete agreement that physician positioning was important; 91% agreement that patient positioning was important; and 82% that ultrasound machine positioning was important. Factors that did not reach our 80% threshold for consensus were further discussed. Four categories were identified as being important when implementing ultrasound ergonomics for BoNT chemodenervation for spasticity; workstation, physician, patient and visual ergonomics. Optimizing ergonomics is paramount when performing US-guided BoNT chemodenervation for spasticity management. This includes proper preparation of the workspace and allowing for sufficient pre-injection time to optimally position both the patient and the physician. Lack of awareness of ergonomics for US-guided BoNT chemodenervation for spasticity may lead to suboptimal patient outcomes, increase work-related injuries, and patient discomfort. We propose key elements for optimal positioning of physicians and patients, as well as the optimal setup of the workspace and provide clinical pearls in visual identification of spastic muscles for chemodenervation.
toxinsOpinionErgonomic Recommendations in Ultrasound-GuidedBotulinum Neurotoxin Chemodenervation for Spasticity:An International Expert Group OpinionPhilippe Lagnau 1,2, Alto Lo 2,3, Ryan Sandarage 2,4 , Katharine Alter 5 , Alessandro Picelli 6 , Jorg Wissel 7,Monica Verduzco-Gutierrez 8, Areerat Suputtitada 2,9 , Michael C. Munin 10, Stefano Carda 2,11, Omar Khan 2,12,Serdar Koçer 13 and Rajiv Reebye 1,2,4,14,*Citation: Lagnau, P.; Lo, A.;Sandarage, R.; Alter, K.; Picelli, A.;Wissel, J.; Verduzco-Gutierrez, M.;Suputtitada, A.; Munin, M.C.;Carda, S.; et al. ErgonomicRecommendations in Ultrasound-Guided Botulinum NeurotoxinChemodenervation for Spasticity:An International Expert GroupOpinion. Toxins 2021, 13, 249.https://doi.org/10.3390/toxins13040249Received: 22 February 2021Accepted: 30 March 2021Published: 31 March 2021Publisher’s Note: MDPI stays neutralwith regard to jurisdictional claims inpublished maps and institutional affil-iations.Copyright: © 2021 by the authors.Licensee MDPI, Basel, Switzerland.This article is an open access articledistributed under the terms andconditions of the Creative CommonsAttribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).1 GF Strong Rehabilitation Centre, Vancouver, BC V5Z 2G9, Canada; philippe.lagnau@aphp.fr2 Canadian Advances in Neuro-Orthopedics for Spasticity Congress (CANOSC), Kingston,ON K7K 1Z6, Canada; aslo@ualberta.ca (A.L.); ryan.sandarage@alumni.ubc.ca (R.S.);prof.areerat@gmail.com (A.S.); stefano.carda@gmail.com (S.C.); omar.khan@hoteldieushaver.org (O.K.)3 Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB T6G 2R3, Canada4 Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada5 Functional and Applied Biomechanics Section, Rehabilitation Medicine, Clinical Center, National Institutes ofHealth, Bethesda, MD 20892, USA; kalter@cc.nih.gov6 Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona,37134 Verona, Italy; alessandro.picelli@univr.it7 Neurological Rehabilitation & Physical Therapy, Department of Neurology with Stroke Unit, VivantesHospital Spandau, 13585 Berlin, Germany; joerg.wissel@vivantes.de8 Department of Rehabilitation Medicine, Joe-R.-and-Teresa-Lozano Long School of Medicine, UT Health SanAntonio, San Antonio, TX 78229, USA; monicaverduzco@hotmail.com9 Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, and KingChulalongkorn Memorial Hospital, Bangkok 10330, Thailand10 Physical Medicine and Rehabilitation School of Medicine, University of Pittsburgh School of Medicine,Pittsburgh, PA 15213, USA; muninmc@upmc.edu11 Neuropsychology and Neurorehabilitation Service, Department of Clinical Neuroscience,Lausanne University Hospital (CHUV), 1011 Lausanne, Switzerland12 Hotel Dieu Shaver Health and Rehabilitation Centre, St. Catharines, ON L2T 4C2, Canada13 Centre de Rééducation Hôpital du Jura, 2900 Porrentruy, Switzerland; serdar.kocer@h-ju.ch14 Division of Physical Medicine and Rehabilitation, University of British Columbia,Vancouver, BC V6T 1Z4, Canada* Correspondence: rajiv.reebye@vch.ca; Tel.: +1-604-544-5044Abstract: Ultrasound (US)-guided botulinum neurotoxin (BoNT) injections are becoming a mainstayin the treatment of muscle spasticity in upper motor neuron syndromes. As a result, there hasbeen a commensurate increase in US-guided BoNT injection for spasticity training courses. How-ever, many of these courses do not emphasize the importance of ergonomics. This paper aims tohighlight the importance of ultrasound ergonomics and presents ergonomic recommendations tooptimize US-guided BoNT injection techniques in spasticity management. Expert consensus opinionof 11 physicians (4 different continents; representing 8 countries, with an average of 12.6 years ofpractice using US guidance for BoNT chemodenervation (range 3 to 22 years)). A search usingPubMed, College of Physicians and Surgeons of British Columbia database, EMbase was conductedand found no publications relating the importance of ergonomics in US-guided chemodenerva-tion. Therefore, recommendations and consensus discussions were generated from the distributionof a 20-question survey to a panel of 11 ultrasound experts. All 11 surveyed physicians consid-ered ergonomics to be important in reducing physician injury. There was complete agreementthat physician positioning was important; 91% agreement that patient positioning was important;and 82% that ultrasound machine positioning was important. Factors that did not reach our 80%threshold for consensus were further discussed. Four categories were identified as being importantwhen implementing ultrasound ergonomics for BoNT chemodenervation for spasticity; workstation,physician, patient and visual ergonomics. Optimizing ergonomics is paramount when performingUS-guided BoNT chemodenervation for spasticity management. This includes proper preparation ofToxins 2021, 13, 249. https://doi.org/10.3390/toxins13040249 https://www.mdpi.com/journal/toxinsToxins 2021, 13, 249 2 of 17the workspace and allowing for sufficient pre-injection time to optimally position both the patientand the physician. Lack of awareness of ergonomics for US-guided BoNT chemodenervation forspasticity may lead to suboptimal patient outcomes, increase work-related injuries, and patientdiscomfort. We propose key elements for optimal positioning of physicians and patients, as wellas the optimal setup of the workspace and provide clinical pearls in visual identification of spasticmuscles for chemodenervation.Keywords: ergonomics; ultrasound-guided; chemodenervation; botulinum neurotoxin; muscle spasticityKey Contribution: Ergonomic recommendations for Ultrasound (US)-guided chemodenervation forspasticity from a panel of 11 international ultrasound physician experts are presented; Four categorieswere identified as being essential by the expert panel to help optimize ergonomics for US-guidedchemodenervation for spasticity: workstation, physician, patient and visual ergonomics.1. IntroductionErgonomics is defined as the study of human factors affecting the worker [physician],with a focus on observing how people interact with their work environment and adaptingthe workplace to the worker, their abilities and limitations [1]. Oftentimes, the goal ofoptimizing ergonomics is to decrease workplace injuries and improve safety while increas-ing workplace efficiency. When applied to physicians using ultrasound (US) guidancefor botulinum neurotoxin (BoNT) injections for spasticity, this consists of analyzing thephysical relationships between the physicians, their patients, and their work environmentto optimize comfort and treatment outcomes.Traditionally, the targeting of muscles for chemodenervation using BoNT was guidedby a combination of anatomical landmarking, direct muscle stimulation with electricalstimulation, and electromyography. However, US guidance is now becoming an increas-ingly utilized guidance method for chemodenervation in patients with spasticity and mayprovide greater anatomic accuracy when compared to traditional methods [2–4]. Further-more, US is a reproducible method for assessing muscle structural architecture which mayhelp guide spasticity treatment in the future [5,6].As higher doses and more frequent dosing of BoNT are now being proposed inthe treatment of spasticity [7–9], it is imperative that proper targeting of the affectedspastic muscles be considered to decrease the risk of iatrogenic BoNT spread into non-targeted muscles.The use of US for injection of BoNT may decrease the risk of iatrogenic BoNT spreadby improving accuracy in targeting certain muscle groups such as the gastrocnemiusmuscle [10–12] and avoiding injection into the neurovascular bundle [3].As a result of evidence that US-guided BoNT injections for spasticity may improvetreatment outcomes [10,11], there has been a proliferation of international training coursesfor US-guided BoNT ultrasound courses for spasticity management [13–17].Due to the challenge of using the two-dimensional image produced by ultrasoundimaging to create a mental three-dimensional representation, many of these courses fo-cus on muscle identification under ultrasound through pattern recognition; understand-ing muscle anatomy and related structures through cadaveric dissection with comparison tocomputed tomography (CT) or Magnetic resonance imaging (MRI) cross-sectional images;and the physics of ultrasound waves to help optimize the ultrasound image for muscleidentification [13,17]. Ergonomic teaching, such as patient and physician positioning andproper transducer/probe grip are usually given limited exposure during these trainingcourses. However, proper ergonomics are important to reduce physician-related injuriesand reduce patient discomfort. Furthermore, proper ergonomics may potentially improvetreatment outcomes by improving the accuracy of muscle identification under ultrasoundand reduction of injection-related errors [18].Toxins 2021, 13, 249 3 of 17This is supported by the findings from the European consensus table on the use ofBoNT in adult spasticity suggesting that non-response to injections may be affected by mul-tiple factors such as insufficient drug dosage, inaccurate muscle selection, and developmentof changes in the targeted muscles (i.e., fibrosis, contracture) as well as by inaccurate injec-tions [19]. While studies have extensively focused on ergonomics in diagnostic ultrasoundsonography [20–22], there are comparatively fewer studies with procedural ultrasound anda search using PubMed, College of Physicians and Surgeons of British Columbia database,EMbase revealed no publications conveying the importance of ergonomics in US-guidedchemodenervation for spasticity.In this narrative review, we outline the importance of ergonomics for US-guided BoNTinjections for spasticity management and the need for further studies to better exploreits impact on physician and patient outcomes. Using images, we also discuss commonergonomic errors made and suggest ergonomic improvements.2. Ergonomics: The RealityTo our knowledge, there are no studies examining ergonomics in US-guided chemod-enervation for spasticity management and its impact on physicians and patients. However,outside of this application, other medical specialists using diagnostic ultrasound imagingand/or US-guided therapeutic injections have highlighted the importance of enhancingergonomics before use. Given the increasing use of ultrasound as a guidance method forBoNT injections and the fact that optimal workplace ergonomics have been proven toreduce work-related musculoskeletal (MSK) injuries [20], specific ergonomic recommenda-tions in this field may be beneficial.MSK pain is common among sonographers. In large-scale studies, Pike et al. andEvans K et al. reported that more than 80% of sonographers develop MSK work-relatedinjuries and continue to work despite their MSK pain [21,22]. The shoulder and the neck arethe most commonly affected body areas with MSK pain in sonographers. In a more recentstudy, a survey conducted on 1234 sonographers confirmed that a high percentage (85.5%)continue to work despite the pain and that the most commonly painful body part is theshoulder [23]. As a result of the increasing awareness of MSK induced disorders in sonog-raphers, the 2003 Industry Standards for the Prevention of Work-Related MusculoskeletalDisorders (WRMSDs) in Sonography were revised in 2016, offering recommendations thatmay assist in the reduction in WRMSDs in users of sonographic equipment [24]. How-ever, these recommendations reflect an “ideal” workplace. In the survey conducted byC. Scholl et al., 26.8% of sonographers identified that these guidelines could not be followedin situations where patients were unable to cooperate due to limited mobility or criticalconditions. These patient factors acted as barriers to applying these industry-standardergonomic scanning techniques [23].Application of these guidelines may also be difficult in US-guided chemodenerva-tion. Patients with spasticity often have decreased mobility and present with decreasedvoluntary muscle movements and have specific posturing of their limbs which makes idealpositioning of limbs for ergonomic injections difficult. This may require an assistant toobtain correct exposure or immobilization of the limb when spasms or excessive nocicep-tive flexion reflexes occur during needle penetration. In other cases, despite the use ofan assistant, proper position of the limb is impossible as the patient may have an MSKcontracture related to their upper motor neuron lesion resulting in decreased passive rangeof motion. In addition, US-guided BoNT chemodenervation shares similar challenges toMSK interventional procedures; these include the use of one hand for probe manipulationand the other hand for injecting while maintaining continuous visualization of the targeton the screen. Guidelines have explored these concepts for procedures such as centralvenous cannulas and joint aspiration/injections [25]. However, for patient-related reasonsas described above, these are not necessarily translatable to US-guided BoNT chemodener-vation. Thus, there are patient and physician factors that can limit ergonomic positioningduring these procedures, resulting in increased WRMSDs.Toxins 2021, 13, 249 4 of 17Although not specifically described in spasticity management, the impact of er-gonomics has been discussed in a recent publication regarding nerve blocks used ininterventional anesthesia [26]. These publications are of interest concerning spasticitymanagement as nerve blocks are becoming more frequently performed to help select mus-cles for chemodenervation. In a study of novice anesthesia resident’s behaviour duringUS-guided nerve block procedures, Sites et al. found that there were ergonomic errorsthat impacted nerve blocks, and these include an arching torso, use of the non-dominanthand holding the needle, or head turned 45◦ or greater. It was hypothesized that thesepositions resulted in unintentional probe movement during the procedures [27]. Poor er-gonomics were furthermore associated with increased injector fatigue which had potentialnegative outcomes such as increased time to perform blocks and possible block failure [27].Thus, the application of these findings to US-guided chemodenervation suggests that poorergonomics could potentially lead to suboptimal outcomes.3. ResultsThere was a response rate of 100% as all 11 injectors replied to the survey. The averageyears of experience regarding using ultrasound guidance for BoNT chemodenervationamong the injectors was 12.6 years (range 3 to22 years) and the average years of experiencewith teaching medical students, post-graduate training physicians and junior physicianstaff relating to US-guided BoNT chemodenervation was 10.5 years (range 2 to 20 years;Table 1). Our injectors identified that only 17.3% (range 0 to 50%) of the ultrasound trainingcourses they have attended formally provided training around ergonomics. There was100% agreement that ergonomics in US-guided BoNT chemodenervation is important inreducing physician injury and 81% agreement that ergonomics is also important for clinicsto run efficiently. Concerning ergonomic optimization, 100% of respondents identified thatphysician positioning was important; 91% identified that patient positioning was important,and 82% identified that ultrasound machine positioning was important. There werevariable opinions on whether other ergonomic factors such as being seated when injecting,visual targeting, and other ergonomic suggestions were important considerations duringinjection (Figure 1A). Consensus opinion regarding common ergonomic errors made bytrainees included the following: inadequate grip of transducer (also termed probe) (91%),inadequate visualization/scouting of nearby structures when injecting (91%) and poorposture during injection (82%). Other errors were identified by our injectors, but they didnot reach the level of consensus opinion (Figure 1B).Table 1. Selected Survey Responses.Question Mean (Range)How many years of experience do you have regarding the use of ultrasound-guided chemodenervation forspasticity management? 12.2 years (3–22)How many years of teaching do you have with regards to training medical students, residents and other juniorstaff physicians in the area of ultrasound-guided chemodenervation? 10.5 years (2–20)In the courses you have attended for ultrasound-guided injection, what percentage formally addressed theproper ergonomics of ultrasound-guided injections? 17.3% (0–50)Question & Responses Responses (%)When you perform ultrasound-guided chemodenervation do you operate alone or with anotherperson assisting?Alone 0 (0%)Assisted 4 (36.4%)Both 7 (63.6%)Some questions in the survey did not reach the 80% threshold level to reach a consen-sus opinion. Discussions were then held between the international experts to elaborateToxins 2021, 13, 249 5 of 17further on the reasons for their responses. The most likely reasons upon discussion weredue to the differences in access to resources, space, and staff.The survey also contained open-ended questions that did not lend themselves wellto a written or figurative summary. However, the answers to these open-ended questionswere used to develop the international expert group recommendations outlined in thediscussion section of this paper.Toxins 2021, 13, x FOR PEER REVIEW 5 of 17 Both 7 (63.6%) Figure 1. Selected survey responses. (A) Elements considered essential to optimize ergonomics for an ultrasound-guided botulinum neurotoxin (BoNT) injection for spasticity management. (B) Expert injector observations of common ergonomic errors made by trainees during ultrasound (US)-guided chemodenervation teaching. Some questions in the survey did not reach the 80% threshold level to reach a con-sensus opinion. Discussions were then held between the international experts to elaborate further on the reasons for their responses. The most likely reasons upon discussion were due to the differences in access to resources, space, and staff. The survey also contained open-ended questions that did not lend themselves well to a written or figurative summary. However, the answers to these open-ended questions were used to develop the international expert group recommendations outlined in the discussion section of this paper. From these answers and discussions, a consensus opinion on the most common er-gonomic mistakes seen by the panel when teaching (Figure 1B), led to four categories Figure 1. Selected survey responses. (A) Elements considered essential to optimize ergonomics for an ultrasound-guidedbotulinum n urotoxin (BoNT) injection for spasticity management. (B) Expert injector observations of common ergonomicerrors made by trainees during ultrasound (US)-guided chemodenervation teaching.From these answers and discussions, a consensus opinion on the most common er-gonomic mistakes seen by the pan l when teaching (Figure 1B), led to four categories iden-tified a bei g important when implementing ul rasound ergonom cs for BoNT chemoden-erva ion for spasticity:Workstat on Ergonomics: Room/ultrasound machi e et-up.Physician Ergon mics: Optimizi g physician p sition, handling of transducer andneedle position.Toxins 2021, 13, 249 6 of 17Patient Ergonomics: Optimizing patient position before to ultrasound guided chemod-enervation procedure.Visual Ergonomics: Optimizing the ultrasound image for bony landmarks and aware-ness of pattern recognition for muscle identification, as well as determination of muscleechogenicity.All 11 experts reviewed and agreed to all of the group recommendations presented inthis paper.4. Discussion4.1. OverviewStandards and studies evaluating the proper ergonomics in diagnostic sonographyhave been previously published. However, none are specific to chemodenervation withBoNT [24,28,29]. In the opinion of our international expert group, optimization of the fourcategories identified (Workstation ergonomics, Physician ergonomics, Patient ergonomicsand Visual ergonomics) may likely improve patient comfort and satisfaction of injection ses-sions; improve physician comfort and reduce physician injuries; reduce procedure-relatederrors (such as unintentional probe movement; misidentification of muscles) resulting inbetter treatment outcomes.We acknowledge that there may be significant differences in access to resources, space,and staff and the following practical clinical pearls regarding workstation ergonomics,physician ergonomics, patient ergonomics and visual ergonomics are recommendationsbased on our consensus opinion.4.2. Workstation Ergonomics4.2.1. Room DimensionsA room that is 150 square feet in size facilitates maneuverability of machine andequipment around the patient [24]. Equipment cords such as power cables, ethernet cables,and other related cables can either be covered to prevent tripping and facilitate movementof a chair over top of the cables, or neatly positioned in such a way as to not interfere withthe injector and assistant movement.4.2.2. Height Adjustable Table and Comfortable ChairIdeally a height-adjustable examination table can be placed at the center of the roomand a swivel rolling chair or examination stool can be used to ease navigation and accessto different injection sites (Figure 2A,B) [24]. A comfortable chair and upright position ofthe body has been shown to reduce the incidence of back pain [30].4.2.3. Ability to Control Room Lighting, Adjusting Ultrasound Machine ParametersAdjusting room lighting and ultrasound parameters (Depth, Focus, Gain, Doppler) andselecting the correct choice of transducer frequency (12–17 Hz: superficial muscles/3–5 Hz:deep muscles) are essential to optimize image quality and to ensure precise targeting [31].4.2.4. Ultrasound Screen at Eye LevelThe ultrasound screen should be at eye level on the opposite side of the physician butwithin arm’s reach to permit ultrasound parameter optimization while scanning beforeinjecting [32]. Ideally, the machine should be directly facing the operator as this results inless rotational movements of the back and neck, decreasing the risk of strain and injury [28].If equipped with one, the foot pedal should be easily accessible for image acquisition.Toxins 2021, 13, 249 7 of 17Toxins 2021, 13, x FOR PEER REVIEW 7 of 17 Figure 2. Workstation ergonomics. (A) Typical setup of an injection room with the examination table against the wall. In this situation, if a patient requires bilateral injections, it would potentially require the patient to be turned to access the limb closer to the wall. In addition, note the second screen on the wall to help with visualization. (B) Ideal workstation setup with examination table centered in the middle of the room with adequate space to move ultrasound machine. (C) Suboptimal positioning with a low chair and elevated table result in hiking of the right shoulder and increased strain on the physician’s shoulder. (D) Bed height and swivel stool height are at an optimal level to allow for the upper extremity to fall naturally and the shoulder to be relaxed. The position of ultrasound is at eye level, also resulting in a comfortable and neutral position of the cervical spine. 4.2.3. Ability to Control Room Lighting, Adjusting Ultrasound Machine Parameters Adjusting room lighting and ultrasound parameters (Depth, Focus, Gain, Doppler) and selecting the correct choice of transducer frequency (12–17 Hz: superficial muscles/3–5 Hz: deep muscles) are essential to optimize image quality and to ensure precise targeting [31]. 4.2.4. Ultrasound Screen at Eye Level The ultrasound screen should be at eye level on the opposite side of the physician but within arm’s reach to permit ultrasound parameter optimization while scanning be-fore injecting [32]. Ideally, the machine should be directly facing the operator as this re-sults in less rotational movements of the back and neck, decreasing the risk of strain and injury [28]. If equipped with one, the foot pedal should be easily accessible for image ac-quisition. Figure 2. Workstation ergonomics. (A) Typical setup of an injection room with the examination table against the wall. In thissituation, if a patient requires bilateral injections, it would potentially require the patient to be turned to access the limbcloser to the wall. In addition, note the second screen on the wall to help with visualization. (B) Ideal workstation setup withexamination table centered in the middle of the room with adequate space to move ultrasound machine. (C) Suboptimalpositioning wit a low chair an elevated table result in hiking of the right shoulder and increased strain on the physician’sshoulder. (D) Bed height and swivel stoo height are at an ptima level to allow for th upper extremity to fall naturally andthe shoulder to be relaxed. The po ition of ultrasound is at eye level, also resulting in a comfortable and neutral position ofthe cervical spine.4.2.5. Having an Assistant AvailableBecause both hands ar ccupie during US-guided injections, ide lly, having anassistant pre ent, especially for n vice injectors, can facilitate correct positioning of limband help with dynamic visualization of muscle group by passively moving the musclewhile it is being scanned [33].4.2.6. Small Portable SurfaceAn easily accessible surface, such as a mobile tray/table should also be within arm’sreach to allow for easy access to additional equipment including alcohol swabs for steril-ization, ultrasound gel for scanning, a surface to rest an EMG/nerve conduction machineand towels to help clean up after the completion of the procedure.4.3. Physician ErgonomicsNeutral Posture: Maintaining a neutral posture is one of the fundamental principles ofproper ergonomics [24]. Certain positions are recognized as optimal in sonography [29]:Toxins 2021, 13, 249 8 of 17(a) Neck should be flexed and not be extended.(b) Forearm horizontal to ground/examination table.(c) Arm abduction less than 30◦.(d) Limited radial and ulnar deviation, less than 15◦ of wrist flexion and extension.(e) Arm should stay vertical at the side of the body with limited shoulder flexion and extension.More specifically with regards to injection under ultrasound guidance:(f) Attempt to have an ultrasound screen in the same line of sight as muscle to injectto minimize the degree of neck movement and facilitate a smooth transition of gazefrom the screen to needle (“look down the barrel”).(g) Avoid excessive scapular protraction when injecting.(h) Physicians should be on the same side as the injected limb to avoid reaching over thepatient, as well as to avoid excessive scapular protraction from excessive reaching.Figure 3A shows incorrect physician positioning for injection of the upper limb andFigure 3B demonstrates the correct ergonomic position for an upper limb ultrasoundguided chemodenervation for BoNT injection.Toxins 2021, 13, x FOR PEER REVIEW 8 of 17 4.2.5. Having an Assistant Available Because both hands are occupied during US-guided injections, ideally, having an as-sistant present, especially for novice injectors, can facilitate correct positioning of limb and help with dynamic visualization of muscle group by passively moving the muscle while it is being scanned [33]. 4.2.6. Small Portable Surface An easily accessible surface, such as a mobile tray/table should also be within arm’s reach to allow for easy access to additional equipment including alcohol swabs for sterili-zation, ultrasound gel for scanning, a surface to rest an EMG/nerve conduction machine and towels to help clean up after the completion of the procedure. 4.3. Physician Ergonomics Neutral Posture: Maintaining a neutral posture is one of the fundamental principles of proper ergonomics [24]. Certain positions are recognized as optimal in sonography [29]: a) Neck should be flexed and not be extended. b) Forearm horizontal to ground/examination table. c) Arm abduction less than 30°. d) Limited radial and ulnar deviation, less than 15° of wrist flexion and extension. e) Arm should stay vertical at the side of the body with limited shoulder flexion and extension. More specifically with regards to injection under ultrasound guidance: f) Attempt to have an ultrasound screen in the same line of sight as muscle to inject to minimize the degree of neck movement and facilitate a smooth transition of gaze from the screen to needle (“look down the barrel”). g) Avoid excessive scapular protraction when injecting. h) Physicians should be on the same side as the injected limb to avoid reaching over the patient, as well as to avoid excessive scapular protraction from excessive reaching. Figure 3A shows incorrect physician positioning for injection of the upper limb and Figure 3B demonstrates the correct ergonomic position for an upper limb ultrasound guided chemodenervation for BoNT injection. Figure 3. Visual comparison of optimal and sub-optimal ergonomics. (A) Sub-optimal ergonomics: The height of the bed is too low for the injector, requiring forward flexion of the trunk. Because of this positioning and because the ultrasound screen is not at eye level, there is a compensatory extension of the neck, resulting in possible neck strain. In addition, both ultrasound machine and targeted limb are away from the injector, resulting in excessive scapular protraction that can result in shoulder pain. (B) Correct ergonomic positioning: Notice the injector seated with the ultrasound machine on the same side as the targeted limb so that there is a direct line of sight (i.e., ability to see the patient, the ultrasound screen, and the limb). In addition, note the position of the transducer grip used for an in-plane injection to the left upper limb flexor carpi radialis muscle. The patient is comfortable, with the left arm in optimal positioning for injection. Notice the injector’s neutral wrist position of the right hand with no excessive flexion and needle positioning (needle at 25 degrees Figure 3. Visual comparison of optimal and sub-optimal ergonomics. (A) Sub-optimal ergonomics: The height of the bedis too low for the injector, requiring forward flexion of the trunk. Because of this positioning and because the ultrasoundscreen is not at eye level, there is a compensatory extension of the neck, resulting in possible neck strain. In addition,both ultrasound machine and targeted limb are away from the injector, resulting in excessive scapular protraction that canresult in shoulder pain. (B) Correct ergonomic positioning: Notice th injector seat d with th ultraso nd machine on thesame side as the targeted limb so that here is a di ect line of sight (i.e., ability to see the pa e t, the u trasound screen,and the limb). In addition, note the position of the transducer grip used for an in-plane injectio to the left upper limb flexorcarpi radialis muscle. The patient is comfortable, with the left arm in optimal positioning for injection. Notice the injector’sneutral wrist position of the right hand with no excessive flexion and needle positioning (needle at 25 degrees insertion andapproximately 0.5 cm to 1 cm from the transducer). The ultrasound machine is well-positioned within easy reach as topermit the ability for image optimization.Seated injections and limiting trunk and neck/flexion: When possible, the physicianshould be seated and limit trunk and neck/flexion as this facilitates neutral posture [28]and improves stability during an injection (Figure 3B).Transducer handling using non-dominant hand, the incorrect position of fingers on thetransducer is associated with higher risks of injury and chronic pain [29,34]. An incorrecttransducer grip for injection is shown in Figure 4A. We recommend handling the transducerusing the index and middle finger with a contralateral thumb grip as this facilitates theuse of the 4th and 5th digits to stabilize the ultrasound transducer against the patient’sskin as shown in Figure 4B,C. This prevents unintentional transducer movement duringinjection and facilitates easy rotation of the ultrasound transducer between the fingerswhile maintaining contact against the patient’s skin, allowing for a seamless transition fromToxins 2021, 13, 249 9 of 17long-axis view to short-axis view while maintaining the area of focus on the ultrasoundscreen (Figure 4C).Toxins 2021, 13, x FOR PEER REVIEW 9 of 17 insertion and approximately 0.5 cm to 1 cm from the transducer). The ultrasound machine is well-positioned within easy reach as to permit the ability for image optimization. Seated injections and limiting trunk and neck/flexion: When possible, the physician should be seated and limit trunk and neck/flexion as this facilitates neutral posture [28] and improves stability during an injection (Figure 3B). Transducer handling using non-dominant hand, the incorrect position of fingers on the transducer is associated with higher risks of injury and chronic pain [29,34]. An incor-rect transducer grip for injection is shown in Figure 4A. We recommend handling the transducer using the index and middle finger with a contralateral thumb grip as this fa-cilitates the use of the 4th and 5th digits to stabilize the ultrasound transducer against the patient’s skin as shown in Figure 4B,C. This prevents unintentional transducer movement during injection and facilitates easy rotation of the ultrasound transducer between the fingers while maintaining contact against the patient’s skin, allowing for a seamless tran-sition from long-axis view to short-axis view while maintaining the area of focus on the ultrasound screen (Figure 4C). Figure 4. Transducer and needle grip. (A) Although the palmar grip reduces the required strength to apply a transducer on the skin, it may result in unintentional movement of the image during injection and makes millimetric shifting for toggling more complex. (B) An optimal probe grip with anchoring to the skin using the 4th and 5th digit increases stability. (C) Notice the injecting hand’s 5th digit is also used to stabilize while administering the product to reduce any undesired needle movement. Physicians should practice scanning and injecting ambidextrously as further practice can develop proficiency in both hands [35]. This is an important skill to develop as there may be situations where, due to room or patient factors, the set up does not allow for ergonomic positioning of the position for dominant hand injections. Figure 4. Transducer and needle grip. (A) Although the palmar grip reduces the required strength to apply a transduceron the skin, it may result in unintentional movement of the image during injection and makes millimetric shifting fortoggling more complex. (B) An optimal probe grip with anchoring to the skin using the 4th and 5th digit increases stability.(C) Notice the injecting hand’s 5th digit is also used to stabilize while administering the product to reduce any undesiredneedle movement.Physicians should practice scanning and injecting ambidextrously as further practicecan develop proficiency in both hands [35]. This is an important skill to develop as theremay be situations where, due to room or patient factors, the set up does not allow forergonomic positioning of the position for dominant hand injections.4.4. Patient ErgonomicsComfortable positioning of patients improves patient experience and safety by reduc-ing the unintentional movement of the patient during the injection. In general, a comfort-able position for a patient involves having the patient and the area injected well-supportedby either the examination bed and pillows or by various other devices such as arm troughsand leg rest. If there are barriers to transferring a patient to a bed or the patient cannot toler-ate a supine or prone position, the patient can be injected while sitting (in their wheelchairor another suitable chair). Additionally, for head/neck and some upper limb injections,a sitting position may provide better access to the region of interest.Patients also often express interest in visualizing the ultrasound screen and procedure.Having a second screen and sharing the screen may be helpful by creating a positiveplacebo effect/biofeedback experience and is beneficial for the doctor-patient relationship.However, if one screen is used, it can result in a suboptimal position, resulting in thephysician tilting his head or stretching his neck to share the monitor with the patient. Thus,Toxins 2021, 13, 249 10 of 17having a second screen is considered optimal to facilitate patient involvement during theprocedure (Figure 2A,C,D).When injecting without assistance, the use of additional devices such as arm troughsor straps may be useful to maintain good exposure to the targeted muscle. However,when possible we recommend having an assistant available for the following reasons:physically assisting with the positioning of the patient for injection; providing emotionalsupport to the patient during the procedure; monitoring the patient’s emotional reac-tion during injection as the physician may be focused on the area of injection and theultrasound screen.4.5. Visual Ergonomics Using UltrasoundAdequate field of view and depth are necessary to recognize bony landmarks. Pa-tients who have had long-standing BoNT injections and increased spasticity often haveincreased muscle fibrosis leading to loss of muscle fascial planes used to delineate musclesfrom each other [12,36,37]. In these cases, it may be necessary to use bony landmarkssuch as the tibia and the interosseous membrane for identifying tibialis posterior or theradius and ulna for flexor compartment muscles as a strategy to identify fibrosed musclesunder ultrasound (Figure 5) and use of the Modified Heckmatt Scale for identification ofmuscle fibrosis [36].Appropriate selection of the ultrasound probe (depending on the depth of the muscle);focus zone selection on the ultrasound machine and adjustment of gain to optimize theimage quality on the screen are also important. These were identified by 73% of our expertsas a common ergonomic error among their trainees. This facilitates the use of patternrecognition which is a common strategy for muscle identification under ultrasound. For ex-ample, in the upper limb, shape recognition of the round muscle belly of the pronator teresmuscle resembling a “ball” and flexor carpi radialis (FCR) looking like a “shark mouth” canbe used by stating that the FCR looks “like a shark” eating the “the ball” of pronator teres(Figure 6A). Optimal image quality also allows for recognizing neurovascular structuresthat may also be helpful for muscle localization. An example is the localization of themedian nerve to identify flexor digitorum superficialis two (FDS2), which is more medialto the median nerve when compared to flexor digitorum superficialis three (FDS 3) [38].In the lower limb, the relationship of flexor digitorum longus having an appearance of“a sail” or “shark-fin” can also help in identifying and targeting this muscle (Figure 6B).Another example where localization of the neurovascular structures can be helpful inmuscle localization is the use of the anterior and posterior branches of the obturator nerveto delineate the fascial planes of the adductor longus, brevis and magnus, as these musclesdo not have clear fascial boundaries on ultrasound (Figure 7A).Identification of these nerve-to-muscle relationships can also be important if diagnosticnerve blocks are used to distinguish contracture versus spasticity (Figure 7A,B).Appropriate selection of acoustic windows will also help determine the best needlepathway/approach. For instance, there are three different approaches to inject tibialisposterior (dorsal, anteromedial, ventral), and depending on the patient’s age and position,the muscle depth and neuro-vascular bundle change, making certain approaches preferable.Furthermore, proper use of gain and ultrasound probe selection can help determinethe level of muscle echointensity (spastic muscles are more hyperechoic secondary tomuscle atrophy, increased fat infiltration and fibrosis), which can be visually assessed bythe Modified Heckmatt scale for spasticity [36]. Picelli et al. demonstrated that outcomes toBoNT may be affected if a spastic muscle is more fibrotic [37]. Furthermore, there is a studythat hypothesizes that identification and injection of the toxin into hypoechoic pockets ofmuscle can theoretically enhance the uptake of BoNT [36].Proper orientation of the ultrasound transducer is necessary for the desired me-dial/lateral, proximal/distal orientation. In radiographic convention, when scanning incross-section, the transducer notch, line, or light is placed to orient left on the displayscreen. This results in images similar to CT or MRI images, where structures on the rightToxins 2021, 13, 249 11 of 17side of the body (such as the liver) are displayed on the left side of the screen. This isreferred to as “standard cross-sectional imaging” [31].Toxins 2021, 13, x FOR PEER REVIEW 11 of 17 . Figure 5. Comparison of normal and spastic muscle with fibrotic changes. (A) Unaffected Right forearm. (B) Affected left forearm with fibrotic changes. Architectural changes in spastic muscle with increased fibrosis on the affected limb modifying the appearance of fascial planes used to delineate the muscles. The use of bony landmarks and adequate scouting of the limb permits the recognition of muscle groups. (FCR: Flexor Carpi Radialis, PT: Pronator Teres, R: Radius, B.A: Brachial Artery, U: Ulna, R: Radius). [Images acquired on Sonosite Xport (FujiFilm Sonosite incor-porated, 21,919 30th Dr. SE, Bothell, WA, USA) using 15–6 Hz linear array transducer]. Appropriate selection of the ultrasound probe (depending on the depth of the mus-cle); focus zone selection on the ultrasound machine and adjustment of gain to optimize the image quality on the screen are also important. These were identified by 73% of our experts as a common ergonomic error among their trainees. This facilitates the use of pat-tern recognition which is a common strategy for muscle identification under ultrasound. For example, in the upper limb, shape recognition of the round muscle belly of the prona-tor teres muscle resembling a “ball” and flexor carpi radialis (FCR) looking like a “shark mouth” can be used by stating that the FCR looks “like a shark” eating the “the ball” of pronator teres (Figure 6A). Optimal image quality also allows for recognizing neurovas-cular structures that may also be helpful for muscle localization. An example is the local-ization of the median nerve to identify flexor digitorum superficialis two (FDS2), which is more medial to the median nerve when compared to flexor digitorum superficialis three (FDS 3) [38]. In the lower limb, the relationship of flexor digitorum longus having an ap-pearance of “a sail” or “shark-fin” can also help in identifying and targeting this muscle (Figure 6B). Another example where localization of the neurovascular structures can be Figure 5. Comparison of normal and spastic muscle with fibrotic changes. (A) Unaffected Rightforearm. (B) Affected left forearm with fibrotic changes. Architectural changes in spastic muscle withincreased fibrosis on the affected limb modifying the appearance of fascial planes used to elineatethe muscles. The use of bony landmarks and dequate scouting of the limb permits th ecognitionof muscle groups. (FCR: Flexor Carpi Radialis, PT: Pronator Teres, R: Radius, B.A: Brachial Artery, U:Ulna, R: Radius). [Images acquired on Sonosite Xport (FujiFilm Sonosite incorporated, 21,919 30thDr. SE, Bothell, WA, USA) using 15–6 Hz linear array transducer].This convention can work well if injecting a patient’s left limb with the ultrasoundscreen at the head of the pati nt, as the notch will be me ial to the patie t. However,when inj cting the right limb with the ultrasound screen at the hea of th patient, this con-vention can be counter intuitive. As can be seen by he figure below (Figure 8), if the notcho other transducer mark were position d medially, as the ransducer moves from theinjector’s left to right (i. ., patient’s lateral to medial), the ultraso nd image n the screenwill move in an opposite direction (i.e., move from right to left). Therefore, it is moreint itive to position the ultrasound ransducer n tch at r lly when injecting the right imb,as demonstrated in the picture. In this setup, s he transducer moves from the injector’sleft to right (i.e., p tient’s lateral to medial), the image on the ultrasound achine will alsomove from left to right, facilitating image interpretation during dynamic scanning.Our expert panel agrees that the transducer notch, light, or line sho ld be positionedsuch that movement of the ultrasound image is a direct reflection of the movement ofthe ultrasound probe on the skin (i.e., simplified cross-sectional imaging). Nonetheless,Toxins 2021, 13, 249 12 of 17physicians must be familiar with standard cross-sectional imaging as well, as imagesproduced in the scientific literature often follow this convention.Toxins 2021, 13, x FOR PEER REVIEW 12 of 17 helpful in muscle localization is the use of the anterior and posterior branches of the ob-turator nerve to delineate the fascial planes of the adductor longus, brevis and magnus, as these muscles do not have clear fascial boundaries on ultrasound (Figure 7A). Identification of these nerve-to-muscle relationships can also be important if diag-nostic nerve blocks are used to distinguish contracture versus spasticity (Figure 7A,B). Appropriate selection of acoustic windows will also help determine the best needle pathway/approach. For instance, there are three different approaches to inject tibialis pos-terior (dorsal, anteromedial, ventral), and depending on the patient’s age and position, the muscle depth and neuro-vascular bun le change, maki g cert in approaches prefera-ble. Figure 6. Visual ergonomics. (A) Positioning transducer one transversal length down from the cubital fossa offers a scout-ing landmark: FCR can be recognized as a “shark eating a ball”, in this case, the ball referring to pronator teres. (FCR: Flexor Carpi Radialis, PT: Pronator Teres, M.N.: Median Nerve). (B) Flexor digitorum longus having an appearance of a “sail” or “shark-fin” just lateral to the tibia can be used to identify other muscles such as the tibialis posterior separated by a fascial plane just underneath. (Images acquired on Esaote MyLab 7 ultrasound machine, Esaote ultrasound machine with 13–3 Hz linear array transducer, (Esaote; location: Fishers, IN, USA)). Figure 6. Visual ergonomics. (A) Positioning transducer one transversal length down from the cubital fossa offers ascouting landmark: FCR can be recognized as a “shark eating a ball”, in this case, the ball referring to pronator teres. (FCR:Flexor Carpi Radialis, PT: Pronator Teres, M.N.: Median Nerve). (B) Flexor digitorum longus having an appearance of a“sail” or “shark-fin” just lateral to the tibia can be used to identify other muscles such as the tibialis posterior separated by afascial plane just underneath. (Images acquired on Esaote MyLab 7 ultrasound machine, Esaote ultrasound machine with13–3 Hz linear array transducer, (Esaote; location: Fishers, IN, USA)).Toxins 2021, 13, 249 13 of 17oxins 2021, 13, x FOR PEER REVIEW Figure 7. Visual Ergonomics. (A) Anterior and posterior branches of the obturator nerve can be used to delineate the fascial planes of the adductor longus, brevis and magnus (B) Visualisation of the median nerve can be used as landmark to identify the Flexor Pollicis Longus. Identification of these nerve to muscle relationships can also be key if nerve blocks are to be performed for diag-nostic injection to determine contracture versus spasticity (FCR: Flexor Carpi Radialis, RA: Radial artery, MN: Median Nerve, FPL: Flexor Pollicis Longus). (Images acquired on Esaote MyLab 7 ultrasound machine, Esaote ultrasound machine with 13–3 Hz linear array transducer, (Esaote; location: Fishers, Indiana, USA)). Furthermore, proper use of gain and ultrasound probe selection can help determine the level of muscle echointensity (spastic muscles are more hyperechoic secondary to mus-cle atrophy, increased fat infiltration and fibrosis), which can be visually assessed by the Modified Heckmatt scale for spasticity [36]. Picelli et al. demonstrated that outcomes to BoNT may be affected if a spastic muscle is more fibrotic [37]. Furthermore, there is a study that hypothesizes that identification and injection of the toxin into hypoechoic pock-ets of muscle can theoretically enhance the uptake of BoNT [36]. Proper orientation of the ultrasound transducer is necessary for the desired me-dial/lateral, proximal/distal orientation. In radiographic convention, when scanning in cross-section, the transducer notch, line, or light is placed to orient left on the display screen. This results in images similar to CT or MRI images, where structures on the right i . Visual Ergonomics. (A) Anterior and posterior branches of the obturator n rve can beelineate the fascial planes of the a ductor longus, brevis and magnus (B) Visualisati nof the median nerve can be used s landmark to identify the Flexor Pollicis Longus. Identificationof these nerve to muscle relationships can also be key if nerve blocks are to be performed fordiagnostic injection to determine contracture versus spasticity (FCR: Flexor Carpi Radialis, RA:Radial artery, MN: Median Nerve, FPL: Flexor Pollicis Longus). (Images acquired on Esaote MyLab7 ultrasound machine, Esaote ultrasound machine with 13–3 Hz linear array transducer, (Esaote;location: Fishers, IN, USA)).Toxins 2021, 13, 249 14 of 17Toxins 2021, 13, x FOR PEER REVIEW 14 of 17 side of the body (such as the liver) are displayed on the left side of the screen. This is referred to as “standard cross-sectional imaging” [31]. This convention can work well if injecting a patient’s left limb with the ultrasound screen at the head of the patient, as the notch will be medial to the patient. However, when injecting the right limb with the ultrasound screen at the head of the patient, this conven-tion can be counter intuitive. As can be seen by the figure below (Figure 8), if the notch or other transducer mark were positioned medially, as the transducer moves from the injec-tor’s left to right (i.e., patient’s lateral to medial), the ultrasound image on the screen will move in an opposite direction (i.e., move from right to left). Therefore, it is more intuitive to position the ultrasound transducer notch laterally when injecting the right limb, as demonstrated in the picture. In this setup, as the transducer moves from the injector’s left to right (i.e., patient’s lateral to medial), the image on the ultrasound machine will also move from left to right, facilitating image interpretation during dynamic scanning. Figure 8. Notch positioning. When injecting the right upper limb, we suggest that the notch be placed laterally as opposed to the radiologic convention of notch medial. The position of the notch laterally allows for the ultrasound image to be a direct reflection of the movement of the ultra-sound probe on the skin. (FDS: Flexor Digitorum Superficialis/Sublimis, M.N.: Median Nerve, U.A. Ulnar Artery, U.N.: Ulnar Nerve) (Images acquired on Esaote MyLab 7 ultrasound machine, Esaote ultrasound machine with 13–3 Hz linear array transducer, (Esaote; location: Fishers, IN, USA)). Our expert panel agrees that the transducer notch, light, or line should be positioned such that movement of the ultrasound image is a direct reflection of the movement of the ultrasound probe on the skin (i.e., simplified cross-sectional imaging). Nonetheless, phy-sicians must be familiar with standard cross-sectional imaging as well, as images pro-duced in the scientific literature often follow this convention. 5. Conclusion Ergonomics in US-guided BoNT chemodenervation for spasticity should be opti-mized to ensure the best outcomes for both the physician and the patient. It currently remains an overlooked aspect of US-guided chemodenervation education courses in spas-ticity management. With the emergence of more accessible ultrasound devices resulting in its increasing use, physicians should take the necessary time before procedures to plan their approaches and optimize positions, which may ultimately increase comfort for both physicians and patients. As ultrasound hardware technology improves, the equipment will become smaller in size and smarter (i.e., handheld tablet, Bluetooth technology) and will likely require regular adjustment to ergonomic standards. Improved ergonomics in US-guided BoNT chemodenervation could also potentially improve clinical outcomes by Figure 8. Notch positioning. When injecting the right upper limb, we suggest that the notch be placed laterally as opposedto the radiologic convention of notch medial. The position of the notch laterally allows for the ultrasound image to bea direct reflection of the movement of the ultrasound probe on the skin. (FDS: Flexor Digitorum Superficialis/Sublimis,M.N.: Median Nerve, U.A. Ulnar Artery, U.N.: Ulnar Nerve) (Images acquired on Esaote MyLab 7 ultrasound machine,Esaote ultrasound machine with 13–3 Hz linear array transducer, (Esaote; location: Fishers, IN, USA)).5. ConclusionsErgonomics in US-guide BoNT chemodenervation for spasticity sh ul be optimizedto ensure best outcomes for both the physi ian and the patient. It currently remainsan overlooked aspect of US-guided chemodenervation education courses in spasticitymanagement. Wi h the emergence of more accessible ultr ound devices resulting inits i creasing use, physicians should take the necessary time before procedures to plantheir approaches and optimize positions, which may ultimately increase comfort for bothphysicians and patients. As ultrasound hardware technology improves, the equipmentwill become smaller in size and smarter (i.e., handheld tablet, Bluetooth technology) andwill likely require regular adjustment to ergonomic standards. Improved ergonomics inUS-guided BoNT chemodenervation could also potentially improve clinical outcomes byreducing the probability of unintentional probe movement and increase the accuracy ofinjection, but this requires further study. Furthermore, novice physicians integrating ultra-sound into their practice could benefit from ergonomic education and this education shouldbe covered during US-guided BoNT for spasticity courses. This would help raise awarenessof best practices and could minimize and prevent injuries before “bad habits/reflexes” areacquired. Future articles exploring the long term economic and productivity outcomes ofsuch interventions would help identify and reinforce best practices. We hope this articlewill be a useful resource for novice physicians in developing sound ergonomic practices inUS-guided BoNT chemodenervation for spasticity. For more experienced physicians, wehope to produce future articles addressing more advanced ergonomic issues in US-guidedchemodenervation such as choosing in-plane/out-of-plane injections, ambidextrous in-jections, and injecting spastic patients with complex patterns of spasticity resulting inabnormal positioning of the limbs. As the objective of this paper was to focus on er-gonomics in US-guided BoNT chemodenervation for spasticity, future publications canexplore the role of ergonomics in US-guided diagnostic nerve blocks, as similar challengesand considerations exist for this important procedure in spasticity management. It is alsoimportant that real world research be conducted to explore whether ergonomics can affectUS-guided BoNT injection outcomes. This knowledge, in addition to the inclusion ofcollaborative research with ultrasound experts, will help in the development of guidelinesfor the use of ultrasound in BoNT chemodenervation.Toxins 2021, 13, 249 15 of 176. MethodsAs the current state of literature in Polymyalgia rheumatica (PMR) is insufficient togenerate ergonomic guidelines, only strategies based on the opinion of experts can beoffered. A working group of four individuals generated a list of 20 statements to form thebasis of an initial survey (Supplementary Materials) to an international group of experts.The international group of US chemodenervation experts consisted of 11 experiencedphysicians in the treatment of spasticity (10 PMR specialists, 1 neurologist) from NorthAmerica, Europe and Asia with academic university appointments and involved in thedevelopment and teaching of US-guided injection courses at a national and internationallevel in the USA, Canada, Italy, Switzerland, Germany and Thailand. An opinion wasconsidered consensus if 80% agreement on a statement was obtained. However, in situ-ations where 80% consensus opinion was not achieved, discussions were held with theexperts concerning these areas of disagreements. Based on these discussions, the consensusopinion on the most common ergonomic mistakes seen by the experts when teachingwas created.Supplementary Materials: Sample Questionnaire are available online at https://www.mdpi.com/article/10.3390/toxins13040249/s1.Author Contributions: Conceptualization, R.R., P.L., A.L., R.S.; methodology R.R., P.L., A.L., R.S.;software, P.L., R.S.; validation, A.L., K.A., A.P., J.W., M.V.-G., M.C.M., A.S., S.C., O.K., S.K. and R.R.;formal analysis P.L., R.R., A.L., R.S.; investigation, A.L., K.A., A.P., J.W., M.V.-G., M.C.M., A.S., S.C.,O.K., S.K. and R.R.; resources, R.R., P.L.; data curation, P.L., R.S.; writing—original draft preparation,P.L., A.L., R.S., K.A., A.P., J.W., M.V.-G., M.C.M., A.S., S.C., O.K., S.K. and R.R.; writing—review andediting, P.L., A.L., R.S., K.A., A.P., J.W., M.V.-G., M.C.M., A.S., S.C., O.K., S.K. and R.R.; visualization,R.R., P.L., R.S.; supervision, R.R.; project administration, R.R.; funding acquisition, R.R. All authorshave read and agreed to the published version of the manuscript.Funding: This research did not receive any specific grant from funding agencies in the public,commercial, or not-for-profit sectors.Institutional Review Board Statement: This study did not require ethical approval. Under article 2.5of the TCPS2 the overarching ethical framework for research involving human participants in CanadaQA/QI activities are exempt from Research Ethics board review. All model and patient ultrasoundimages are under ethics approval H180178 (approved on 23 August 2018) from the University ofBritish Columbia and patient has consented to the use of their images.Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.Data Availability Statement: Not Applicable.Conflicts of Interest: The authors declare no conflict of interest.AbbreviationsBotulinum neurotoxin BoNTUltrasound USWork-Related Musculoskeletal Disorders WRMSDsMusculoskeletal MSKReferences1. 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ergonomics
ultrasound-guided
chemodenervation
botulinum neurotoxin
muscle spasticity
Ergonomic Recommendations in Ultrasound-Guided Botulinum Neurotoxin Chemodenervation for Spasticity: An International Expert Group Opinion
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