Fibro-adipogenesis in Injured Rotator Cuff Muscle

Purpose of Review Fibro-adipogenic progenitors were first characterized in 2010 and later found to contribute significantly to muscle regeneration and mediate degenerative changes in muscle following injury. These progenitors were also found to have an influence on the rotator cuff muscle’s response to chronic injury which is defined by fibrosis accompanied by massive fatty degeneration. The purpose of this review is to highlight progenitor cells, their contribution to fibro-adipogenesis in rotator cuff tissue, and the factors influencing fibro-adipogenesis in this tissue. Recent Findings Fibro-adipogenic progenitors are a key mediator of the fatty infiltration notably prevalent in rotator cuff injury. Relative to other muscle groups, the rotator cuff has relatively high rates of fibro-adipogenesis following massive chronic rotator cuff tears. This may be linked to the pre-injury density of fibro-adipogenic progenitors in muscle tissue affecting post-injury levels of fibro-adipogenesis. In addition, suprascapular nerve injury in rat models of rotator cuff tears has demonstrated worse, histologic, and biomechanical properties and lower healing rates of rotator cuff repairs. However, fatty infiltration in the rotator cuff following suprascapular nerve compression has been shown to be reversible following release of the nerve compression. Summary The fibro-adipogenic response to acute and chronic injury in rotator cuff tissue is determined by a complex array of factors including progenitor cell influence, transcriptional pathways, chronicity of the injury, anatomic location of injury, microenvironmental influences, and the severity of nerve involvement. Elucidating the complex interactions of these factors will provide potential targets for therapeutic intervention in vivo.

The Structure of the Brachial Plexus of the Djungarian Hamster (Phodopus sungorus)

Hamsters are often chosen as companion animals but are also a group of animals frequently subjected to laboratory tests. As there are no scientific publications providing information on the anatomical architecture of the brachial plexus of the Djungarian hamster, this study analyses the structure of this part of the nervous system of this species. It is important to know the details of this structure not only for cognitive reasons, but also due to the increasing clinical significance of rodents, which are often used in scientific research. The study was conducted on 55 specimens. Like in humans, the brachial plexus of the Djungarian hamster has three trunks. The following individual nerves innervating the thoracic limb of the Djungarian hamster: the radial nerve, median nerve, ulnar nerve, musculocutaneous nerve, axillary nerve, suprascapular nerve, thoracodorsal nerve, cranial pectoral nerves, caudal pectoral nerve, lateral thoracic nerve, long thoracic nerve, and subscapular nerves. Similarly to other mammals of this order, the brachial plexus of the Djungarian hamster ranges widely (C5-T1). However, its nerves are formed from different ventral branches of the spinal nerves than in other mammals.

A COMPARISON OF SUPRASCAPULAR NERVE BLOCK VS INTRAARTICULAR STEROID INJECTION IN IMPROVEMENT OF HEMIPLEGIC SHOULDER PAIN

Objectives: To compare the mean improvement in pain on Visual Analogue Scale by Suprascapular Nerve block and Intra-articular steroid injection in patients with hemiplegic shoulder pain. Study Design: Randomized Controlled Trial Place and Duration of Study: Pain Clinic, Armed Forces Institute of Rehabilitation Medicine Rawalpindi from 25th October 2017 to 24th April 2018 Patients & Methods: 60 patients with CVA and shoulder pain on hemiplegic side for at least 2 weeks were included in study after non-probability consecutive sampling after meeting inclusion criteria. Subjects were randomized by lottery into two groups; Group A receiving Suprascapular Nerve block with 5ml of 1% Lignocaine with Group B receiving Intra-articular 40mg Triamcinolone Acetonide plus 1 ml of 1% Lignocaine injections. Mean change in pain scores on VAS was calculated between score at baseline and at 4 weeks post-intervention Results: The mean age of patients in group A was 59.17 ± 9.81 years and in group B was 39.96 ± 11.11 years. Out of 60 patients, 34 (56.67%) were males and 26 (43.33%) were females with male to female ratio of 1.3:1. Mean duration of stroke was 7.50 ± 2.66 months. Mean pain change on VAS in Group A (Suprascapular Nerve block) was 3.83 ± 1.12 cm while in Group B (Intra-articular steroid injection) it was 2.17 ± 0.99 cm (p-value = 0.0001). Conclusion: This study concluded that Suprascapular Nerve block offered better improvement in hemiplegic shoulder pain on Visual Analogue Scale at 4 weeks as compared to intraarticular steroid injection.

Application of Dexmedetomidine Sedation Combined With Suprascapular Nerve Block and Axillary Nerve Block in Shoulder Arthroscopy, A Randomized Single-Blind Study

Objective: The aim of the present study was to evaluate the anesthetic and analgesic effects of dexmedetomidine combined with suprascapular nerve block and axillary nerve block in shoulder arthroscopy.Methods: A total of 60 patients were randomly divided into the experimental group (DEX group) and the control group (GA group) via a random number table method. Dexmedetomidine sedation combined with suprascapular nerve block and axillary nerve block was used in the DEX group, while general anesthesia with tracheal intubation combined with interscalene brachial plexus block was used in the GA group. The perioperative indexes, intraoperative hemodynamics, cerebral oxygen saturation, and postoperative pain score, as well as any complications, were compared between the two groups.Results: The anesthesia duration (p < 0.05) and postoperative monitoring time (p < 0.05) in the DEX group were significantly shorter than those in the GA group. At most time points during the anesthesia, the cerebral oxygen saturation (p < 0.05) and mean arterial pressure (p < 0.05) in the DEX group were significantly higher than those in the GA group. Additionally, the decrease in the cerebral oxygen saturation and mean arterial pressure in the GA group was significantly higher than that in the DEX group (p < 0.05). The pain score of DEX group 12 h after operation significantly lower than that in the GA group (p < 0.05), and the incidence of postoperative hypoxemia along with nausea and vomiting in the GA group was significantly higher than that in the DEX group (p < 0.05).Conclusion: Dexmedetomidine combined with suprascapular nerve block and axillary nerve block could reduce the incidence of hypoxemia, while the approach demonstrated better hemodynamic stability, fully ensured the cerebral blood perfusion, and exhibited better anesthetic and analgesic effects, meaning it could be safely and effectively applied in shoulder arthroscopy procedures.

Unprecedented emergencies during radiofrequency ablation procedure: a case series

Radiofrequency ablation (RFA) of nerves is an upcoming intervention for relieving chronic musculoskeletal pain. However, being relatively new not much publications are available on emergencies during the procedure. 66 years old male, a case of Osteoarthritis knee, underwent RFA genicular nerve of right knee. Conventional RFA of Superolateral, Inferomedial, Superomedial genicular nerves were done under C- arm guidance. Thirty minutes after the procedure, we found a boggy swelling developing over his right knee. It was a hematoma developing on the superomedial aspect of the right kneecap most likely due to injury to Superomedial genicular vessels accompanying the nerve. 67 years old female planned for RFA genicular nerves of both knees under C arm guidance. During the intervention, she complained of numbness around face, and suddenly went into disoriented state with muscle twitching and bluish discoloration of lips. Medicine consultation diagnosed the incident as LA associated systemic toxicity. 57 years old female with chief complaints of pain in left hemiplegic shoulder pain for 6 months duration admitted for suprascapular nerve block. During the procedure patient goes into hypotensive bradycardic episode. 65 years old female admitted for Medial calcaneal block for right heel pain. 24 hours after the procedure she has aggravated pain of foot. RFA is considered as a non-invasive, OPD based procedure for effective pain relief but it is also important to understand such unprecedented emergencies that can happen.