Unknown variant of the accessory subscapularis muscle?

Acting in medial rotation of the arm, the subscapularis (SM) is the most powerful and largest muscle of the rotator cuff. It is morphologically variable, especially in the number of tendons, place of insertion, and number of bellies, and it is sometimes fused with another muscle. An accessory subscapularis muscle (ASM) is among the morphological variations of the SM, but it is a really rare variant. The present case describes a very rare ASM that is divided into proximal tendinous attachment, intermediate fleshy muscular belly and distal tendinous attachment. Its origin is located on the lateral border of the scapula, but some fibers are connected with the muscular part of the SM. Its distal attachment is fused with the capsule of shoulder joint, above the tendinous insertion of the SM. Such an arrangement allows for greater stabilization of the joint. Moreover, there is a possibility that it could be used during treatment of ruptured SM tendons.

A COMPARATIVE STUDY BETWEEN EFFICACIES OF USG GUIDED BOTULINUM TOXIN INJECTION INTO THE SUBSCAPULARIS MUSCLE AND THE CONSERVATIVE TREATMENT IN HEMIPLEGIC SHOULDER PAIN

Introduction: Hemiplegic shoulder pain (HSP) is a common complication after stroke. HSP inhibits recovery and rehabilitation and impairs the quality of life of stroke survivors. Although the etiology of HSP is not well known, it has been suggested that multiple factors contribute to HSP. Our approach is to compare the efcacy of USG guided Botulinum toxin injection into the subscapularis muscle and conservative treatment in case of intractable hemiplegic shoulder pain. Material and methods: In this Parallel Group Open Level Randomized Controlled Trial, conducted in the Department of Physical Medicine and Rehabilitation, IPGME&R, SSKM Hospital, Kolkata between September, 2017 to September, 2018 (Twelve months) on 34 (17 in each group) patients with intractable (persistent pain for more than 3 months) hemiplegic shoulder pain. In group 1, Botulinum toxin injection was given in subscapularis muscle by USG guided lateral approach. In group 2, managed conservatively with Physical therapy (stretching, passive range of motion exercise), Modality (hot pack, infrared, IFT), pain medications (NSAIDS, oral opioids) and Neuromuscular electrical stimulation of shoulder. Parameters used: 1. Pain intensity - measured by Numerical Rating Scale (NRS) [Score 0- 10], 2. Spasticity measured by - Modied Ashworth Scale (MAS) [score 0-4], 3. Shoulder range of motion - External rotation (ER) [score 0- 90] assessed. The patients attending the Physical Medicine and Rehabilitation OPD at IPGME&R and SSKM Hospital, Kolkata were included and studied if they fullled the inclusion and nd exclusion criteria after getting Institutional Ethics Committee clearance and informed written consent. After initial visit, followed up on 2 week, th th 4 week and 12 week. Comparison done considering all the parameters considering basal and follow up data to compare the efcacy of intramuscular botulinum toxin injection and those with in group 2, managed conservatively. Results: All the data collected during this study period were analyzed by using statistical software Statistica vertsion 6 [Tulsa, Oklahoma: StatSoft Inc., 2001] and GraphPad Prism version 4 [San Diego, California: GraphPad Software Inc., 2005]. There was statistically signicant difference (group 1 is statistically superior than group 2) between two groups at 2nd, 4th and 12th week in respect to NRS, MAS of subscapularis and ER of shoulder joint (p value<0.05). Conclusion: There was signicant short-term improvement of shoulder pain, spasticity of shoulder internal rotator(subscapularis) and range of motion in the form of external rotation after Botulinum toxin injection compared to conservative treatment. But in terms of intermediate-term and long-term follow-up although both groups showed signicant improvement but Botulinum toxin injection group was statistically superior than conservative treatment.

Atrophy patterns in isolated subscapularis lesions

Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

Results of Modified Mini-Open Arthroscopically Assisted Bristow - Latarjet - Bankart Procedure

The aim of the study — to evaluate clinical outcomes, complications, bone-block healing, positioning and subscapularis muscle insufficiency after modified mini-open arthroscopically assisted Bristow - Latarjet - Bankart procedure.Materials and Methods. The study included 133 patients who underwent modified mini-open arthroscopically assisted Bristow - Latarjet - Bankart procedure, assessed the functional outcome using the Rowe and Walch-Duplay scales, the range of motion and stability of the joint, and the function of the subscapularis muscle. All patients underwent CT, 82 patients were assessed for MR-signs of subscapularis muscle atrophy.Results. All patients were satisfied with the treatment results. The mean value on the Rowe scale increased from 35.7 [31,2; 41,0] to 91.3 [82,1; 96,8] (38 to 100 Me 90) (p<0.001) and on the Walch-Duplay scale from 41.5 [34,2; 44,5] to 88.9 [80,4; 97,2] (32 to 100, Me 88) (p<0.001). In 2 (1.5%) patients, shoulder dislocation recurred, in 9 (6.8%) patients, a positive test of premonition of dislocation or periodic feelings of instability were observed. There were no persistent contractures. In 6 (4.5%) cases, the graft was located medially and in 3 (2.3%) cases — laterally. The average α-angle was 14° [5°; 24°] (2° to 39°, Me 15). The proportion of the graft area lost due to resorbtion was 19% [9%; 30%] (from 6 to 58%, Me 20). Nonunion of the graft was observed in 4 (3.0%) patients, 2 (1.5%) of whom had a fracture and bone block migration. A significant (p = 0.021) decrease in the intensity of the MR-signal of the subscapularis muscle was observed, most pronounced in the lower portion. In 9 patients with a positive test of anticipation of dislocation or sensations of instability, the degree of bone block resorption (p = 0.038) and MR-signs of atrophy of the upper and lower portions of the subscapularis muscle were significantly higher (p = 0.031 and p<0.001), and the results of stress testing significantly worse (p<0.001) than in 122 patients without signs of instability.Conclusion. The results of this study show the efficacy of the modified arthroscopically-assisted Bristow - Latarjet - Bankart procedure in patients with large bone defects, when the soft tissue technique is not a reasonable option.

Improved long-term functional outcome after a latissimus dorsi transfer with or without subscapularis muscle lengthening or release

A brachial plexus birth injury (BPBI) can lead to a limited shoulder function, especially abduction and external rotation. One of the treatment options to restore those shoulder functions is a latissimus dorsi transfer (LDT). The aim of this study is to analyze long-term functional outcome after a single LDT and compare these results with LDT combined with subscapularis muscle lengthening (SSL) or subscapularis muscle release (SSR). This cohort study included 39 patients (≤12 years old) with one-sided BPBI. All patients had an inter- nal rotation- and adduction contracture without glenohumeral joint deformity. A LDT was performed with or without SSL or SSR, resulting in 3 patient study groups. Demographic data and pre- and post- operative Mallet scores were collected and analysed for each group. The median age was 4.0 years (IQR 3.1) and there were no differences in patient demographics. In all patients surgery improved external rotation and overall shoulder function, at 9.8 years follow-up. Also, the total Mallet score increased significantly with 1.7 (p=0.001) in our (entire) study cohort. A LDT, with a SSL or SSR in case of an intra-operative internal contracture, improves shoulder function and preserves external rotation in patients (≤12 years old) with BPBI, at a follow up of 9.8 years.

Muscle volume imbalance may be associated with static posterior humeral head subluxation

Background The transverse force couple (TFC) of the rotator cuff (subscapularis vs. infraspinatus and teres minor muscle) is an important dynamic stabilizer of the shoulder joint in the anterior-posterior direction. In patients with posterior static subluxation of the humeral head (PSSH), decentration of the humeral head posteriorly occurs, which is associated with premature arthritis. We hypothesize that not only pathologic glenoid retroversion but also chronic muscle volume imbalance in the transverse force couple leads to PSSH. Methods A retrospective analysis of the TFC muscle volumes of 9 patients with symptomatic, atraumatic PSSH, within 8 were treated with glenoid correction osteotomy, was conducted. The imaging data (CT) of 9 patients/10 shoulders of the full scapula and shoulder were analyzed, and the muscle volumes of the subscapularis (SSC), infraspinatus (ISP) and teres minor muscles (TMM) were measured by manually marking the muscle contours on transverse slices and calculating the volume from software. Furthermore, the glenoid retroversion and glenohumeral distance were measured. Results The mean glenoid retroversion was − 16° (− 7° to − 31°). The observed mean glenohumeral distance was 4.0 mm (0 to 6.8 mm). Our study population showed a significant muscle volume imbalance between the subscapularis muscle and the infraspinatus and teres minor muscles (192 vs. 170 ml; p = 0.005). There was no significant correlation between the subscapularis muscle volume and the glenohumeral distance (r = 0.068), (p = 0.872). Conclusion The muscle volume of the SSC in patients with PSSH was significantly higher than the muscle volume of the posterior force couple (ISP and TMM). This novel finding, albeit in a small series of patients, may support the theory that transverse force couple imbalance is associated with PSSH. Level of evidence Level 4 – Case series with no comparison group.

Variations in Subscapularis Muscle Innervation—A Report on Case Series

Background and objectives: The subscapularis muscle is typically innervated by two distinct nerve branches, namely the upper and lower subscapular nerve. These usually originate from the posterior cord of the brachial plexus. A large number of variations have been described in previous literature. Materials and Methods: Dissection was carried out in 31 cadaveric specimens. The frequency of accessory subscapular nerves was assessed and the distance from the insertion points of these nerves to the myotendinous junction was measured. Results: Accessory subscapular nerves were found in three cases (9.7%). According to their origin from the posterior cord of the brachial plexus proximal to the thoracodorsal nerve all three nerves were identified as accessory upper subscapular nerves. No accessory lower subscapular nerves were found. Conclusion: Accessory nerves occur rather commonly and need to be considered during surgery, nerve blocks, and imaging procedures.