Comparative anatomy of the subscapularis, teres major and latissimus dorsi muscles from salamanders to mammals with special reference to their innervations from the brachial plexus

It has been reported that the ramification pattern of spinal motor nerves reflected the spatial orientation of motoneuron pools in the ventral horn of spinal cord and this topography of spinal motor nuclei was very similar in different vertebrates. Therefore, the ramification pattern of spinal nerves was an important criterion for discussing the phylogenetic homology of muscles. It has been reported that the human subscapularis muscle was innervated by several branches, the proximal branch of them was from the ventral layer of the dorsal cord and the distal one from the dorsal layer of the dorsal cord of the brachial plexus. This fact suggested the human subscapularis had different phylogenetic origins. In this study, I unveil the phylogenetic origin of the mammalian subscapularis. The animals observed were a chimpanzee, a lar gibbon, a cat, a fetal pig, a koala, a possum (mammals), a lizard, an iguana (reptiles) and salamanders (amphibians). The branches to the mammalian subscapularis were divided into proximal and distal groups based on the origin from the brachial plexus, just like the human subscapularis. In salamanders and lizards, the homologous branch with the mammalian proximal branch to the subscapularis was observed and the segmentally higher branch innervating the latissimus dorsi was homologous with the distal branch to the mammalian subscapularis. Conclusively, I suppose that the dorsal-most portion of the reptilian latissimus dorsi muscle differentiates to the mammalian teres major, and the segmentally higher portion of the reptilian latissimus dorsi contributes to the formation of the mammalian subscapularis.

Scapular Retraction under Adduction Load: An Alternative to Overhead Exercises to Activate Infraspinatus, Upper, and Lower Trapezius in Subjects with and without Shoulder Pain

Exercises for lower trapezius (LT) often use overhead positions, causing compressive forces to the subacromial space. Scapular retraction would be an alternative to activate LT muscle. The present study aimed to assess the excitation levels of infraspinatus, upper trapezius, and lower trapezius muscles during a scapular retraction exercise under progressive adduction loads in subjects with and without painful shoulder. Electromyography of infraspinatus (IS), upper trapezius (UT), and LT was recorded during scapular retraction under progressive adduction loads of 42 participants, divided into two groups: with (SP, n = 26) and without shoulder pain (nSP, n = 16). The adduction loads of 20%, 30%, 40%, and 50% of the maximal voluntary contraction (MVC) were applied using a load cell. Normalized electromyography and the ratio between UT and LT (UT:LT) were used for statistical analysis. No differences were observed between groups, but a condition effect occurred for all muscles: UT showed higher values at 50% vs. 20% of MVC (p = 0.004); LT showed higher values on 40% and 50% of MVC (p = 0.001; 0.006). Higher values for IS were noted at 40% of MVC (vs. 20% of MVC; p = 0.04) and at 50% of MVC (vs. 20% of MVC; p = 0.001, vs. 30% of MVC, p = 0.001; vs. 40% of MVC; p = 0.001). UT:LT showed lower values at 50% of MVC (vs. 20% of MVC; p = 0.001 and vs. 30% of MVC; p = 0.016). Scapular retraction with adduction loads at 40-50% is an alternative to overhead exercises aiming to activate the LT and the IS muscles. The exercise ensures higher levels of LT and IS excitation without increasing UT excitation.

Investigation of Effectiveness of Two Different Kinesiotaping Techniques in Myofascial Pain Syndrome: An Open-Label Randomized Clinical Trial

BACKGROUND

Myofascial pain syndrome is a regional musculoskeletal pain syndrome characterized by trigger points. Although there are widely accepted treatment modalities, there is no gold standard treatment. Kinesiotaping represents an interesting modality in the treatment of musculoskeletal disorders and attracts attention with studies emerging in the recent years, but in spite of the proposed benefits of kinesiotaping, its efficacy is still unclear, thus further studies evaluating the effectiveness of kinesiotaping are needed.

OBJECTIVES

We aimed to investigate, not only the effectiveness of kinesiotaping applied with the space correction and muscle inhibition techniques (compared to the home exercise program in reducing pain and improving functional status and quality of life in female patients with myofascial pain syndrome related to active trigger points in the upper trapezius), but also to evaluate the superiority of the 2 techniques over each other.

STUDY DESIGN

An open-label randomized clinical trial with a parallel assignment intervention model.

SETTING

The physical medicine and rehabilitation clinics in Istanbul University, Istanbul Faculty of Medicine.

METHODS

Seventy-one female patients with the complaint of pain in the upper trapezius region, diagnosed with myofascial pain syndrome, and having at least one active trigger point in the upper trapezius fibers, were randomly assigned by a computer program to 1 of the 3 groups: kinesiotaping with the space correction technique (KSCT, n = 20), kinesiotaping with the muscle inhibition technique (KMIT, n = 24), and the home exercise program alone (control group [CG], n = 27). The patients were evaluated by the numerical rating scale for pain intensity, the neck disability index for functional status, and the 36-Item Short-Form Health Survey for quality of life in the beginning of the study and at the first, second, and sixth weeks (1-month follow-up).

RESULTS

Kinesiotaping was associated with lower pain intensity levels (P = 0.019 at the first week and P = 0.026 at the second week) and better functional status (P = 0.011 at the second week) and it was effective in increasing quality of life by improving physical functions and general health (P = 0.033 and P = 0.003 at the second week, respectively) earlier than in the CG. Role limitations due to physical factors improved in the KMIT group earlier than in the other groups (P = 0.022 at the second week).

LIMITATIONS

Being performed in a limited number of female patients only, absence of a placebo group, and lack of blinded assessments.

CONCLUSION

Both kinesiotaping methods were associated with lower pain intensity levels and better functional status and were effective in increasing quality of life by improving physical functions and general health earlier than the home exercise program. There was no significant difference between the kinesiotaping methods, except for role limitations due to the physical factors domain of SF-36 which was improved in the KMIT group earlier than in the KSCT group and CGs.

Ergonomic arm support prototype device for smartphone users reduces neck and shoulder musculoskeletal loading and fatigue

Smartphone use is a risk factor for both neck and shoulder musculoskeletal disorders. The objective of this study was to evaluate an ergonomic arm support prototype device, which may help improve posture while using a smartphone, by determining its effect on muscle activity, muscle fatigue, and neck and shoulder discomfort. Twenty-four healthy young adult smartphone users performed 20 min of smartphone game playing under two different conditions, smartphone use with support prototype device (i.e. intervention condition) and without (i.e. control condition), while neck and shoulder posture were controlled at 0° neck flexion and 30° shoulder flexion. Activity and fatigue of four muscles were measured using surface electromyography (sEMG), these were: anterior deltoid (AD), cervical erector spinae (CES), upper trapezius (UT) and lower trapezius (LT). The intervention condition showed significantly decreased activity of all muscles. Fatigue of all muscles, except LT, significantly increased over time compared to the start point in the control condition. There was no significant difference in muscle fatigue between each time point in the intervention condition. In conclusion, the ergonomic arm support prototype device can be used as ergonomic intervention to reduce neck and shoulder muscle loading and fatigue.

Rehabilitation Exercises for Dysfunction of the Scapula: Exploration of Muscle Activity Using Fine-Wire EMG

BACKGROUND

Scapular muscle activity during shoulder exercises has been explored with surface electromyography (EMG). However, knowledge about the activity of deeper-layer scapular muscles is still limited.

PURPOSE

To investigate EMG activation of the deeper-layer scapular stabilizers (levator scapulae [LS], rhomboid major [RM], pectoralis minor [Pm] muscles) together with superficial muscle activity (upper [UT], middle [MT], and lower trapezius [LT] and serratus anterior [SA]) during 4 exercises often used for training scapular function. Based on the amplitude EMG of the deeper-layer muscles, scapular muscle activation ratios for the 4 exercises were calculated, hereby providing knowledge of the optimal muscle balance.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 26 healthy participants performed 4 shoulder exercises (side-lying external rotation [ER], side-lying forward flexion, prone horizontal abduction with ER, and prone extension) while simultaneously measuring scapular muscle activity. Intramuscular electrodes were used for the deeper layer, in contrast to surface electrodes for the superficial muscles. All data were normalized to percentage of maximal voluntary isometric contraction (%MVIC), and the activation ratios (the muscle activity of the deeper layer relative to the other muscles) were calculated. A 1-way analysis of variance with Bonferroni correction was applied for statistical analysis.

RESULTS

Moderate activity was found in all exercises for the LS and RM (25%-45% MVIC). The Pm resulted in low activity during both side-lying exercises (13%-18% MVIC). Ratios involving LS or RM showed values >1 for all exercises (1.28-12.41) except for LS/MT, LS/LT, and LS/RM (0.85-0.98) during side-lying ER, and LS/MT, RM/MT and RM/LS (0.85-0.99) during side-lying forward flexion. Likewise, values <1 were found when MT (0.85) and LS (0.99) were involved with RM in the numerator during side-lying forward flexion. Ratios with Pm in the numerator showed values <1, apart from the ratios with UT and SA in the denominator.

CONCLUSION

The study provides extended knowledge about the deeper-layer scapular muscle activity and related ratios during the 4 shoulder exercises mentioned here. Putting theory into practice, based on our results, we advise both side-lying exercises to be performed to strengthen LT and MT, even in case of hyperactivity of the Pm. However, the 4 exercises should be given carefully to patients with hyperactivity in the LS and/or RM.

CLINICAL RELEVANCE

The findings of this study may assist clinical decision making in exercise selection for restoring scapular function.

Scapula alata: diagnosis and treatment by nerve surgery and tendon transfers

Scapula alata, also known as winged scapula, can lead to severe upper limb impairment. The shoulders' function is altered because the scapula, which supports the upper limb, is no longer stable. Typical scapula alata is described for serratus anterior palsy; however, any scapulothoracic muscle impairment may lead to scapular winging, particularly trapezius palsy, which is easy to miss, thus needed to be considered as a differential diagnosis. The diagnosis is difficult and based on various clinical tests and a thorough examination as well as electroneuromyography and MRI. The treatment ranges from conservative treatments for spontaneous recovery, nerve surgery including neurolysis, nerve transfers and nerve grafts for acute cases, to tendon transfers for more chronic cases and when nerve procedures are no longer feasible. Tendon transfers in serratus anterior palsy produce excellent results with a high rate of patient satisfaction and are described with the sternal or clavicular head of the pectoralis major; we describe our preferred technique in this article. Tendon transfers in trapezius palsy are performed with the levator scapulae, rhomboid minor and major muscles. Our preferred method is the Elhassan triple transfer. Scapula alata is a frequent and often misdiagnosed condition. Appropriate management can yield excellent results. Patients should be referred right away to specialized centers for surgery if recovery is not spontaneous.

Prospective, randomized evaluation of latissimus dorsi transfer and superior capsular reconstruction in massive, irreparable rotator cuff tears

BACKGROUND

The treatment of massive, irreparable rotator cuff tears remains controversial today because there is no consensus on the ideal treatment option. This investigation aimed to prospectively evaluate and compare the outcomes of arthroscopy-assisted latissimus dorsi transfer and superior capsular reconstruction in the treatment of massive, irreparable rotator cuff tears.

METHODS

Forty-two patients at an average age of 62.8 years with massive, irreparable rotator cuff tears were randomized into 2 treatment groups. Twenty-one patients underwent arthroscopy-assisted latissimus dorsi tendon transfer (LDT), and 21 patients underwent arthroscopy-assisted superior capsular reconstruction (SCR). The patients were followed up prospectively for 31 months on average. One patient in the SCR group was lost to follow-up. The outcomes were evaluated with American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Western Ontario Rotator Cuff Index (WORC), visual analog scale (VAS), and Constant scores clinically and with acromiohumeral distance (AHD) measurements radiologically.

RESULTS

Both groups displayed improved results in ASES, WORC, Constant, and VAS scores in the final follow-up (P < .001). The LDT group had significantly better results in AHD (P = .006), whereas the SCR group yielded significantly higher improvements in ASES (P = .007) and Constant (P = .008) scores. The rate of successful pseudoparalysis treatment was 45% (5/11) in the LDT group and 92% (12/13) in the SCR group (P = .011). The graft failure rate was 5% (1 patient) in each group postoperatively; 1 patient in the SCR group had a traumatic graft rupture and 1 patient in the LDT group was complicated with septic arthritis, which required graft removal.

CONCLUSION

Both SCR and LDT yielded promising short-term results in treatment of massive, irreparable rotator cuff tears in this study. The SCR group displayed better overall outcomes clinically, particularly in the pseudoparalytic shoulders, whereas the LDT group displayed better radiologic results.

Tendon transfers to restore elbow flexion

Elbow flexion paralysis is one of most significant deficiencies in the upper limb. When secondary to brachial plexus palsy or nerve trunk lesions, restoration of elbow flexion by means of early nerve surgery or palliative transfers should be part of a comprehensive treatment plan. Tendon transfers are indicated in long-standing palsies, in those who are poor candidates for nerve surgery or when the results of nerve surgery are inadequate. A regional pedicled muscle transfer is performed if available. In this case, a "strong" donor is preferred (pectoralis major with pectoralis minor transfer, triceps brachii to biceps brachii transfer, or bipolar latissimus dorsi transfer). A "weak" transfer is indicated in patients who have incomplete recovery of elbow flexion (MRC 2 strength): isolated pectoralis minor transfer, medial epicondylar muscle transfer according to Steindler technique, or advancement of biceps brachii tendon on forearm. When no donor muscle is available, a free reinnervated muscle transfer may be indicated if age and nerve regeneration conditions are favorable.

The effectivity of a passive arm support exoskeleton in reducing muscle activation and perceived exertion during plastering activities

The supportive effect of arm-support exoskeletons has been mainly studied for single postures or movements. The aim of this study is to analyse the effect of such an exoskeleton on shoulder muscle activity and perceived exertion, in six tasks of plasterers, each including multiple arm movements. The tasks of 'applying gypsum', 'screeding' and 'finishing' were performed at a ceiling and a wall, with exoskeleton (Exo) and without (NoExo). EMG was recorded of six muscles involved in upper arm elevation, four agonists and two antagonists, and plasterers rated their perceived exertion (RPE). In all tasks, the EMG amplitudes of three agonist muscles, Trapezius and Medial Deltoid, and Biceps Brachii, were lower in Exo vs NoExo, while the agonist, Anterior Deltoid, showed lower EMG values in Exo in most tasks. None of the antagonists (Triceps Brachii, Pectoralis Major) showed increased EMG values in the Exo condition. RPE's were lower in Exo condition for all tasks, except for 'applying gypsum to the wall'. Overall, the exoskeleton seems to reduce loads in realistic plastering tasks. Practitioner summary: Exoskeletons are an emerging technology in the field of ergonomics. Passive arm support exoskeletons have mainly been tested in lab studies using continuous overhead work, involving one posture or movement. However, in reality, working tasks generally involve multiple movements. This study investigates the effectiveness of an arm support exoskeleton in work that requires multiple arm movements, specifically in plastering. Muscle activity, as well as perceived exertion were both reduced when working with an exoskeleton. Abbreviations: Exo: with exoskeleton; NoExo: without exoskeleton; RPE: rated perceived exertion; EMG: electromyography; Trap: upper trapezius; AD: anterior deltoid; MD: medial deltoid; BB: biceps brachii; TB: triceps brachii; PM: pectoralis major; RPD: rated perceived discomfort; p50: 50th percentile; p90: 90th percentile; MVC: maximum voluntary contraction; GEE: generalised estimated equations.

The Technique of Scarless Latissimus Dorsi in Immediate Breast Reconstruction

Background: In dealing with the inferior pole coverage of an implant or a tissue expander in the partial submuscular technique, various surgical strategies have been introduced over the years. Among them, ADM and synthetic meshes were intensively studied and performed in order to obtain a good aesthetic result with satisfactory lower pole contouring, create a strong support of the implant and offer flexibility in adapting the volume of a tissue expander to the remaining mastectomy flaps (1,2). However, the viability of the skin from the mastectomy flaps is not always optimal. Vascular impairment and subsequent necrosis can occur at various extent in the mastectomy flaps (3). The necrosis of the mastectomy flaps is unpredictable and sometimes occurs with no obvious cause (4). Implant exposure and extrusion, ADM or mesh exposure are serious complications which can lead to the reconstructive failure. Methods: The scarless latissimus dorsi flap technique was introduced and observed in patients eligible for skin sparing and nipple sparing mastectomy with implant-based submuscular breast reconstruction. The keypoints of the surgical steps are described. Results: The main priorities of the outcome of the reconstructive process were stability and good definition of the lower pole of the reconstructed breast. The good vascularized underlying muscular tissue totally covering the implant increases chances in avoiding exposure or extrusion of the implant. In the advent of partial mastectomy flap necrosis, the healing by secondary intention provided good and stable results. Also, this technique decreases the morbidity and risks related with the change of the patient position during the procedure, improves the aesthetic results, by avoiding additional incisions for harvesting the flap. Conclusions: The scarless latissimus dorsi flap in implant based breast reconstruction is a valuable option for stable results and viable alternative to the use of ADM.

Tips and Tricks for Successful Breast Reconstruction Following Radiotherapy Using the Implant-Enhanced Latissimus Dorsi Flap

Introduction: Adjuvant radiotherapy poses the most serious challenges for surgeons who must choose both the time and the optimal reconstructive method for radiotherapy patients. One of the postmastectomy reconstructive techniques, in patients subjected to radiotherapy, is the method that combines the own tissue with the alloplastic material, the latissimus dorsi flap and the breast implant. This method is highly versatile and can be safely applied to radiotherapy patients. Materials and Methods: Between April 2014 and April 2020, we performed 219 breast reconstructions of which 156 cases were reconstructed with latissimus dorsi flap and implant. The main elements studied were: patient selection for the above mentioned technical procedure, indication of operative moment and type of intervention, preoperative measurements and sketching, minimal scar of the donor area, decision to perform simultaneous symmetrization, simultaneous prophylactic mastectomy with immediate reconstruction, cosmetic appearance, stability and evolution of results over time. The follow-up period was 1 year for all patients, while in the case of some patients up to 5 years. Results: This technique could be applied in all cases with radiotherapy, regardless of the size of the contralateral breast, the technique allowing the shaping of breasts of different volumes. The cosmetic appearance has improved over time, the breast having characteristics similar to the healthy one - shape, natural ptosis, consistency, well-defined inframammary groove. Simultaneous symmetrization by breast reduction, mastopexy with or without implant or breast augmentation led to superior results and a high degree of patient satisfaction. The average duration of recovery was 4 weeks, with rapid social and professional reintegration of patients. The small number of complications - 1 total flap necrosis, 3 cases of partial necrosis, 5 seromas, with a small number of reinterventions - 4, make this method one of the safest in the difficult context of the radiotherapy treatment of prepectoral area. Conclusions: Careful planning of breast reconstruction with the help of the latissimus dorsi flap in combination with the breast implant, the meticulous technique determines stable results over time, with superior cosmetic appearance of the breasts reconstructed with the aid of this method, while minimizing the risk of complications. Thus, the quality of life of patients is much improved, and the social and professional reintegration is relatively fast.

Trapezius Tear Causing Scapular Winging Treated with Rhomboid Transfer and Achilles Allograft Reconstruction: A Case Report

CASE

This is a case of an 18-year-old woman with superior and lateral scapular winging due to traumatic injuries to the insertions of the superior and middle trapezius as well as the origins of the latissimus dorsi and lower trapezius.

CONCLUSION

Scapular winging can be caused by a muscle tear in absence of a nerve injury. This patient underwent latissimus dorsi origin repair and superior and middle trapezius repairs. An Achilles allograft was used to reconstruct her lower trapezius to provide static restraint to her scapula, while a rhomboid major transfer was performed to provide dynamic restraint.

The Chimeric Scapulodorsal Vascularized Latissimus Dorsi Nerve Flap for Immediate Reconstruction of Total Parotidectomy Defects With Facial Nerve Sacrifice: Building a New Program and Preliminary Results From 25 Cases

BACKGROUND

Total parotidectomy with facial nerve sacrifice creates 2 challenging reconstructive problems: restoration of facial contour and facial nerve rehabilitation. Strong evidence suggesting that vascularized nerve grafts are superior to nonvascularized nerve grafts motivated our team to develop a chimeric scapulodorsal flap combining the usual harvestable local tissues with the vascularized latissimus dorsi motor nerve (SD-LDVxN). We present our experiences developing a new program at University of California, San Diego, highlighting our first case here, and present preliminary retrospective results focusing on the functional outcomes of facial nerve reanimation.

MATERIALS AND METHODS

The first case performed in the United States was a 57-year-old woman with stage IVA left parotid adenoid cystic carcinoma and House-Brackmann grade 6 facial palsy. She underwent total parotidectomy with facial nerve sacrifice and a free chimeric SD-LDVxN flap reconstruction. She had an unremarkable postoperative course, and 3- and 6-month follow-up functional results are reported. Preliminary functional results from our total series of 25 patients were reported.

RESULTS

At her 3-month follow-up, she was a House-Brackmann 5 with a static eFACE score of 37, dynamic eFACE score of 31, and smile eFACE score of 48. At her 6-month follow-up, she was a House-Brackmann 5 with a static eFACE score of 50, dynamic eFACE score of 27, and smile eFACE score of 53. Preliminary results from our total series of 25 patients with an average of 5 years of follow-up were a House-Brackmann 2.5 and eFACE scores of 83.1 for static facial symmetry, 67.5 for dynamic facial symmetry, and 77.7 for smile score. Twenty of the 25 patients had postoperative radiotherapy. No local tumor recurrence had been reported. The average reinnervation time was 9 months and ranged from 3 to 15 months.

CONCLUSIONS

The SD-LDVxN flap is a highly resourceful solution to reconstruct complex parotid defects, especially those that sacrifice the facial nerve. The vascularized nerve graft allows for primary facial reanimation. Nerve recovery may be superior to what could be expected with a conventional nerve graft.

Wrapping technique and wrapping height interact to modify physical exposures during manual pallet wrapping

Occupational tasks often involve musculoskeletal demands that contribute to injury risk. In pallet wrapping tasks, 36% of workplace claims involve over exertion and repetitive exposures (Workplace Safety and Prevention Services, 2012). Tools that modify how the wrap is handled by workers have been introduced to help mitigate over exertion and extreme postures wherever possible. A novel device has been introduced that places the required tension on the roll to mitigate these factors. However, the effect of reducing the necessary tension on the roll during pallet wrapping in limiting muscular demand and extreme postures is unknown. Fourteen healthy university aged participants completed 12 wrapping trials on a simulated pallet (2 repetitions of 2 wrapping techniques (device, hand wrapping) at 3 wrapping heights (low, medium, high)). Surface electromyography (sEMG) was measured on 6 shoulder and 2 low back muscles; anterior and middle deltoids, biceps brachii, infraspinatus, supraspinatus, upper trapezius, and erector spinae (T8 & L3). Kinematic data were collected for the torso and upper extremity and global to torso, and torso to upper arm angles were computed. Repeated measures ANOVAs were performed for the following experimental factors: 1) technique used (device or hand wrapping) and 2) the wrapping height (low, medium, high) for each muscle (8), angle (5), rating of perceived discomfort (1) and rating of perceived exertion (1). Pallet wrapping without a device required greater trunk flexion at lower heights and thoracohumeral elevation at higher wrapping heights as compared to using the device. Muscular activation increased when using the device, specifically at the higher and lower heights. Posture and muscular demands during pallet wrapping tasks are sensitive to both wrapping technique and wrapping height. Ergonomics interventions such as this device may mitigate postural risks associated with manual material handling tasks.

Manual material handling in the supermarket sector. Part 1: Joint angles and muscle activity of trapezius descendens and erector spinae longissimus

Work-related musculoskeletal disorders are highly prevalent in the supermarket sector with manual material handling being one of the most commonly identified occupational risk factors. This cross-sectional study applied inertial motion capture and electromyography (EMG) to measure full-body kinematics and muscle activity of trapezius descendens and erector spinae longissimus during 50 manual material handling tasks performed by 17 workers in two supermarkets. The handling of bread and cucumbers to high shelf heights showed the highest trapezius muscle activity (from 47% to 59% peak normalized EMG), while the handling of bananas as well as lifting milk, bread and cucumbers from low to high positions showed the highest erector spinae activity (from 59% to 71%). Twenty-two tasks involved flexing the shoulders and trunk more than 90° and 50°, respectively. Based on these results, several manual handling practices in supermarkets should be reconsidered to reduce the physical work demands.

Effects of break scheduling strategies on subjective and objective measures of neck and shoulder muscle fatigue in asymptomatic adults performing a standing task requiring static neck flexion

Sustained non-neutral postures of the head/neck are related to transient neck discomfort and longer-term disorders of the neck. Periodic breaks can help but the ideal length and frequency of breaks are yet to be determined. The current study aimed to quantify the effects of three work-rest strategies on fatigue development. Participants maintained a 45-degree neck flexion posture for a total of 60 min and were provided 3 min of rest distributed in different ways throughout the experiment [LONG (one, 3-min break), MEDIUM (two, 1.5-min breaks), or SHORT (five, 36-s breaks)]. Surface electromyography data were collected from the bilateral neck extensors and trapezius. Subjective discomfort/fatigue ratings were also gathered. Results of the analysis of the EMG data revealed that the SHORT condition did not show increased EMG activity, while LONG [21%] and MEDIUM [10%] did (p < 0.05), providing objective data supporting the guidance of short, frequent breaks to alleviate fatigue.

Enhancement of External Rotation after Latissimus Dorsi Tendon Transfer (LDTT): A Cadaveric Study

Background and objectives: Massive rotator cuff tears compromise shoulder mobility function and cannot be directly repaired. Latissimus dorsi tendon transfer (LDTT) is a therapeutic alternative suitable for the treatment of rotator cuff tears that helps to restore external shoulder rotation. Cadaver models have been used for studying the effects of LDTT and procedural variations, but, to the best of our knowledge, none of them have been validated. The aim of our study was to validate a novel cadaver model while verifying the effects of LDTT on external rotation. Materials and Methods: Two groups were included in the study: a cadaver group and a control group made up of healthy volunteers, which were used for the validation of the cadaver model. Baseline external rotation measurements were performed with both groups, after which a massive rotator cuff tear was inflicted and repaired with LDTT in the cadaver group. Their postoperative external rotation was evaluated using three different tests. Results: No statistically significant differences were found between the baseline measurements of the two groups, and postoperative external rotation was significantly higher after LDTT in all cases but one. Conclusions: Cadaver models were validated, since they had a similar preoperative external rotation to healthy volunteers. Moreover, they allowed us to demonstrate the effect of LDTT on external shoulder rotation.

Acute effect of inhibitory kinesio-tape of the upper trapezius on lower trapezius muscle excitation in healthy shoulders

INTRODUCTION

Shoulder pain increases excitation of the upper trapezius (UT) and reduces excitation in the lower trapezius (LT). Despite inconclusive evidence, kinesio-tape (KT) is often used to modify muscular excitation within the UT and/or LT to help correct alterations in scapular position and motion associated with shoulder pain/injury. The objective of the current study was to determine if inhibitory KT to the UT acutely increases LT excitation and if load alters the magnitude of change in the excitation observed.

METHODS

Twenty-two (N = 22, 11 female) individuals with healthy shoulders (24 ± 3 years) completed 10 repetitions of an arm elevation task during 3 taping conditions (no-tape, experimental KT, sham KT) and 2 loading conditions (no load and loaded). Whole-muscle (mean grid) and spatial distribution (grid row) of LT excitation (root mean squared; RMS) was measured using a single high-density surface electromyography 32-electrode grid.

RESULTS

There was a main effect for loading condition on whole-muscle LT RMS, F (1, 19) = 38.038, p < .001, partial η² = 0.667. Whole-muscle LT RMS was significantly higher in the loaded condition (0.055 V ±0 .005) compared to the no-load condition (0.038 V ±0 .004). No effect of tape condition was observed on whole-muscle or spatial distribution of RMS.

CONCLUSION

Our findings suggest that inhibitory KT to the UT does not alter whole-muscle excitation or shift the distribution of excitation within the LT during a repeated arm elevation task in healthy shoulders.

Effects of Dry Needling on Muscle Stiffness in Latent Myofascial Trigger Points: A Randomized Controlled Trial

The aim of this study was to analyze the effects of dry needling (DN) in upper trapezius latent trigger points (LTrPs) on muscle stiffness. A total of 51 recreational physically active subjects with LTrPs in the upper trapezius volunteered to participate and were randomly divided into a DN-group (n = 27) and a sham-DN group (n = 24). Volunteers received 1-session of DN or placebo treatment. Muscle stiffness, measured with strain and shear-wave elastography, pressure pain threshold (PPT), post-needling soreness, and muscle thickness were evaluated before treatment, and at 30-min, 24-hours, and 72-hours follow-up after treatment. The DN-group showed lower values from baseline for muscle stiffness measured with shear-wave elastrography at 24-hours (from 44.44 ± 15.97 to 35.78 ± 11.65 kpa; P < .01) and at 72-hours (35.04 ± 12.61 kpa; P < .01) and with strain elastography at 72-hours (from 1.75 ± 0.50 to 1.36 ± 0.40 AU; P < .01). The DN-group showed higher values of PPT than the sham-DN group at 72-hours (4.23 ± 0.75 vs. 5.19 ± 1.16 kg/cm²; P < .05). There was a progressive decrease in post-needling soreness compared to pain during needling of 33.13 ± 21.31% at 30-min, 80.92 ± 10.06% at 24-hours, and a total decrease in post-needling soreness in all participants at 72-hours. DN therapy is effective in reducing short-term muscle stiffness and increasing the PPT in volunteers with LTrPs in the upper trapezius after a treatment session. PERSPECTIVE: This study found that one session of DN intervention in latent trigger points of the upper trapezius muscle reduced muscle stiffness and the pressure pain threshold for the dry needling group compared to the sham dry needling group.

Short-term outcomes of arthroscopic partial repair vs. latissimus dorsi tendon transfer in patients with massive and partially repairable rotator cuff tears

BACKGROUND

There is limited evidence on clinical outcomes of arthroscopic partial repair (APR) and latissimus dorsi tendon transfer (LDTT) for posterosuperior massive rotator cuff tears (mRCTs). We aimed to compare clinical outcomes of APR and LDTT for partially repairable posterosuperior mRCTs and to determine whether outcomes differ among tears that involve the teres minor.

METHODS

We retrieved the records of 112 consecutive patients with mRCTs deemed partially repairable due to fatty infiltration (FI) stage ≥3 in one or more rotator cuff muscles. Of the tears, 12 involved the subscapularis, 32 were managed conservatively, 14 were treated by reverse shoulder arthroplasty, and 7 were treated by stand-alone biceps tenotomy. Of the remaining 47 shoulders, 26 underwent APR and 21 underwent LDTT. At a minimum of 12 months, we recorded complications, active forward elevation, external rotation, the Constant-Murley score, American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), and Simple Shoulder Test (SST) score.

RESULTS

No significant differences between the APR and LDTT groups were found in terms of follow-up (23.4 ± 3.5 months vs. 22.1 ± 4.1 months, P = .242), Constant-Murley score (64.8 ± 13.7 vs. 58.9 ± 20.0, P = .622), ASES score (78.3 ± 19.3 vs. 74.4 ± 14.5, P = .128), active forward elevation (158.1° ± 19.4° vs. 142.8° ± 49.1°, P = .698), or external rotation (33.3° ± 17.4° vs. 32.2° ± 20.9°, P = .752). By contrast, the APR group had a higher SSV (73.3 ± 17.5 vs. 59.5 ± 20.0, P = .010), and SST score (8.3 ± 2.4 vs. 6.4 ± 3.0, P = .024). Univariable analysis revealed that advanced FI of the teres minor compromised Constant-Murley scores (β = -25.8, P = .001) and tended to compromise ASES scores (β = -15.2, P = .062). Multivariable analysis corroborated that advanced FI of the teres minor compromised Constant-Murley scores (β = -26.9, P = .001) and tended to compromise ASES scores (β = -16.5, P = .058).

CONCLUSION

Both APR and LDTT granted similar early clinical outcomes for partially repairable posterosuperior mRCTs, regardless whether the teres minor was intact or torn. Advanced FI of the teres minor was the only independent factor associated with outcomes, as it significantly compromised Constant-Murley scores and tended to compromise ASES scores.

Evaluation of fatigue patterns in individual shoulder muscles under various external conditions

For shoulder muscle prevention, we investigated individual shoulder muscle performance and fatigue patterns in various external conditions, including three different % maximum voluntary contractions, six shoulder angles and 60-s durations of exertion. The rating of perceived exertion was also measured for comparison. The upper trapezius (UT), middle deltoid (MD), pectoralis major (PM), latissimus dorsi (LD) and serratus anterior (SA) were selected for assessment. Normalized median power frequency electromyograms were calculated for quantitative fatigue evaluation in ten participants. UT muscle was severely fatigued by extreme flexion angle rather than weight. MD muscle was the most rapidly fatigued after 15 s duration. SA muscle was more fatigued at 0° than 30° adduction. LD and PM muscle fatigue were mostly due to external workload. This muscle specific outcome could help practitioners to design an intervention program targeting particular shoulder injury.

Effect of a Long Exercise Program in the Reduction of Musculoskeletal Discomfort in Office Workers

The purpose of this study was to assess the effect of a six week exercise program to reduce the muscle tone of the trapezius and musculoskeletal discomfort (MED) of office workers. Twenty-six workers performed an exercise program based on: (1) stretching of cervical and/or dorsal region; (2) joint mobility of shoulders and rachis; (3) strengthening deep stabilizer and core muscles; and (4) scapula stabilizing exercises. A Myoton device was used to evaluate trapezius tone and the Cornell Musculoskeletal Discomfort Questionnaire was used to assess changes in MED at three points of evaluation: at the beginning (Pre_1) and at the end of the workday (Post_1), and after the training program (Pre_2). The Wilcoxon test and Cohen’s d were performed to examine differences and effect sizes between evaluations. Main results show that trapezius tone remained constant during the workday, but decreased in the dominant upper trapezius (p = 0.003, ES = −0.60) and increased in the non-dominant middle trapezius (p = 0.016, ES = 0.45) after the exercise program, which eliminated significant muscle asymmetries. MED significantly decreased in the neck (p = 0.027, ES = −0.60) and upper back (p = 0.046, ES = −0.67). In conclusion, MED appears to improve in office workers after a six week training program, which may be explained by a decrease in trapezius tone and increase in the left middle trapezius tone.

Rare Pseudotumor-like Hematoma at the Latissimus Dorsi Muscle Flap Donor Site: A Treatment Strategy Utilizing Negative Pressure Wound Therapy With Instillation and Dwell Time

INTRODUCTION

In reconstructive surgery, the latissimus dorsi (LD) muscle is known as a workhorse flap and is commonly used as a pedicled or free flap. Postoperative complications of a reconstructive procedure with an LD flap include seroma and hematoma formation at an early stage after LD transfer. Late-onset hematoma at the donor site are considered to be extremely rare postoperative complications; late, expanding pseudotumor-like hematoma can occur months or years after surgery. Shearing forces and poor coagulation are thought to be the primary reasons for these postoperative complications.

CASE REPORTS

This report presents 2 cases of pseudotumors 12 and 29 years after LD transfer. Magnetic resonance imaging was performed prior to complete surgical excision. After surgical removal, patients received negative-pressure wound therapy with instillation and dwell time (NPWTi-d) for several days. After vacuum-assisted wound bed preparation, wound closure was performed with secondary sutures.

CONCLUSIONS

The case report presented 2 incidences of rare late-onset pseudotumors many years after the initial LD reconstruction. To the authors' knowledge, this late-onset occurrence (ie, after 3 decades) has not been reported in the literature to date. If solidification of the late hematoma makes aspiration impossible, surgical intervention is required. Negative pressure wound therapy with instillation and dwell time potentially minimizes the wound size and reduces shear forces at the back donor-site.

Determining safe teaching board heights through electromyographic analysis of the shoulder muscles

BACKGROUND

Adjustable teaching boards have been recommended as an ergonomic practice geared at reducing the incidences of teaching-related shoulder musculoskeletal disorders among teachers. However, there are no standards guiding choice of appropriate teaching board heights. This study was aimed at evaluating shoulder muscle activities in response to five teaching board heights.

METHODS

Thirty participants performed writing activities on five different board heights (Diff10 = standing height minus 10% of standing height; NormH = participant's standing height; Sum10 = standing height plus 10% of standing height; Sum20 = standing height plus 20% of standing height; Sum25 = standing height plus 25% of standing height). Electromyographic analysis of the anterior deltoid (AD), upper trapezius (UT), serratus anterior (SA) and pectoralis major (PM) muscles were performed simultaneously during each task. Data were analyzed with one-way ANOVA and independent T-test at p < 0.05.

RESULTS

Sum20 board height significantly (p < 0.001) elicited the highest activities in the AD (19.35 ± 11.26%) and UT (29.06 ± 29.53%) muscles while SA (20.37 ± 10.87%) and PM (20.86 ± 12.17%) muscles were most active at Sum25 board height. SA and PM muscles progressively increased with increasing board heights while AD and UT muscles showed alternating patterns of activation at increasing board heights. For safe ergonomic practices, recommended teaching board heights should be within the range of NormH and Sum10.

CONCLUSION

Extremely high or low teaching boards have tendencies of inducing musculoskeletal shoulder discomforts.

Evaluation of the Combination of Muscle Energy Technique and Trigger Point Therapy in Asymptomatic Individuals with a Latent Trigger Point

(1) Background: The aim of the study was to determine the effect of the combination therapy of Muscle Energy Technique (MET) and Trigger Point Therapy (TPT) on the angular values of the range of movements of the cervical spine and on the pressure pain threshold (PPT) of the trapezius muscle in asymptomatic individuals. METHODS: The study involved 60 right-handed, asymptomatic students with a latent trigger point in the upper trapezius muscle. All qualified volunteers practiced amateur symmetrical sports. The study used a tensometric electrogoniometer (cervical spine movement values) and an algometer (pressure pain threshold (PPT) of upper trapezius). Randomly (sampling frame), volunteers were assigned to three different research groups (MET + TPT, MET and TPT). All participants received only one therapeutic intervention. Measurements were taken in three time-intervals (pre, post and follow-up the next day after therapy). (2) Results: One-time combined therapy (MET + TPT) significantly increases the range of motion occurring in all planes of the cervical spine. One-time treatments of single MET and single TPT therapy selectively affect the mobility of the cervical spine. The value of the PPT significantly increased immediately after all therapies, but only on the right trapezius muscle, while on the left side only after the therapy combining MET with TPT. (3) Conclusion: The MET + TPT method proved to be the most effective, as it caused changes in all examined goniometric and subjective parameters.