Externally applied force helps reduce bowstring effect of flexors in patients with carpal tunnel release surgery.

BACKGROUND: Patients with severe carpal tunnel syndrome (CTS) undergo carpal tunnel release (CTR) surgery to alleviate pressure in the carpal tunnel. However, the subsequent lack of the transverse carpal ligament (TCL) causes the bowstring phenomenon of the flexor tendons and increases the potential incidence of trigger finger. OBJECTIVE: This study aimed to investigate the effects of various compressive forces on the flexor tendon and identify the appropriate force needed to mitigate the bowstring effect of those flexors. DESIGN: Cross-sectional repeated measures comparison. METHOD: Thirteen CTS patients who underwent CTR surgery were asked to flex the middle finger while applying different external compressive forces, just contact, 4N, and 8N force, over the carpal tunnel. Images of the flexor tendon within the carpal tunnel and at the metacarpal phalangeal (MCP) joint were recorded via ultrasound. RESULT: Results show that the compression force limited the volar migration of the flexor tendon under maximal voluntary contraction (MVC) conditions. Entrance angles between the flexor tendon and metacarpal bone also decreased as the external compressive force increased. CONCLUSIONS: Findings of this study may indicate that applying compression force on the carpal tunnel is useful for CTS patients and can inhibit the volar shift of the flexor digitorum superficialis (FDS) tendon after surgery, which may further prevent trigger finger.

Systematic Review of Diagnostic Sensors for Intra-Abdominal Pressure Monitoring.

Intra-abdominal pressure (IAP) is defined as the steady-state pressure within the abdominal cavity. Elevated IAP has been implicated in many medical complications. This article reviews the current state-of-the-art in innovative sensors for the measurement of IAP. A systematic review was conducted on studies on the development and application of IAP sensors. Publications from 2010 to 2021 were identified by performing structured searches in databases, review articles, and major textbooks. Sixteen studies were eligible for the final systematic review. Of the 16 articles that describe the measurement of IAP, there were 5 in vitro studies (31.3%), 7 in vivo studies (43.7%), and 4 human trials (25.0%). In addition, with the advancement of wireless communication technology, an increasing number of wireless sensing systems have been developed. Among the studies in this review, five presented wireless sensing systems (31.3%) to monitor IAP. In this systematic review, we present recent developments in different types of intra-abdominal pressure sensors and discuss their inherent advantages due to their small size, remote monitoring, and multiplexing.

An Ingestible Electronics for Continuous and Real-Time Intraabdominal Pressure Monitoring.

Abdominal compartment syndrome can be treated through decompressive surgery if intraabdominal hypertension (IAH) can be detected in time. Treatment delays due to manual, conventional intravesical pressure (IVP) monitoring using a Foley catheter have been reported. In this work, we present an innovative gastrointestinal intraluminal pressure (GIP) measurement-based method to monitor and improve pressure-guided relief of intraabdominal pressure (IAP). A novel algorithm for detecting IAH in the gastrointestinal tract of a live porcine model is reported. A wireless pressure-sensing capsule (10 × 13 mm) was developed for absolute measurement. The IAP was estimated during artificial pneumoperitoneum. The pressure waveform-based measurements indicated that the wireless pressure sensor could be used to predict IAP. To enhance GIP monitoring for predicting IAH, the proposed continuous ingestible wireless electronics-based pressure waveform measurement device can be used as a complement to existing modalities. The use of the proposed pressure measurement and communication technology can help provide valuable data for digital health platforms.

Overexpression of Insulin-Like Growth Factor 1 Enhanced the Osteogenic Capability of Aging Bone Marrow Mesenchymal Stem Cells.

Many studies have indicated that loss of the osteoblastogenic potential in bone marrow mesenchymal stem cells (bmMSCs) is the major component in the etiology of the aging-related bone deficit. But how the bmMSCs lose osteogenic capability in aging is unclear. Using 2-dimentional cultures, we examined the dose response of human bmMSCs, isolated from adult and aged donors, to exogenous insulin-like growth factor 1 (IGF-1), a growth factor regulating bone formation. The data showed that the mitogenic activity and the osteoblastogenic potential of bmMSCs in response to IGF-1 were impaired with aging, whereas higher doses of IGF-1 increased the proliferation rate and osteogenic potential of aging bmMSCs. Subsequently, we seeded IGF-1-overexpressing aging bmMSCs into calcium-alginate scaffolds and incubated in a bioreactor with constant perfusion for varying time periods to examine the effect of IGF-1 overexpression to the bone-forming capability of aging bmMSCs. We found that IGF-1 overexpression in aging bmMSCs facilitated the formation of cell clusters in scaffolds, increased the cell survival inside the cell clusters, induced the expression of osteoblast markers, and enhanced the biomineralization of cell clusters. These results indicated that IGF-1 overexpression enhanced cells' osteogenic capability. Thus, our data suggest that the aging-related loss of osteogenic potential in bmMSCs can be attributed in part to the impairment in bmMSCs' IGF-1 signaling, and support possible application of IGF-1-overexpressing autologous bmMSCs in repairing bone defect of the elderly and in producing bone graft materials for repairing large scale bone injury in the elderly.

Effect of Astragalus membranaceus in rats on peripheral nerve regeneration: in vitro and in vivo studies.

BACKGROUND: This study provides in vitro and in vivo evaluation of Astragalus membranaceus (AM) on peripheral nerve regeneration. METHODS: In the in vitro study, we analyzed the effects of AM on cell differentiation and neurite outgrowth by using a PC12 cell model. In the in vivo study, silicone rubber chambers filled with the AM water extract were used to bridge a 10-mm sciatic nerve defect in rats. RESULTS: We found that the AM water extract caused a marked enhancement of the nerve growth factor-mediated neurite outgrowth and the expression of growth-associated protein 43 from PC12 cells. Animals from the groups treated with the AM for 8 weeks had a relatively more mature structure with larger mean values of myelinated axon number, endoneurial area, and total nerve area when compared with those in the controls receiving the saline only. CONCLUSION: These results suggest that the silicone rubber tubes present a good framework for the nerve fibers to regenerate across the gap, and the AM extract can be a potential nerve growth-promoting factor, being salutary in aiding the growth of axons in the peripheral nerve.

Highly permeable genipin-cross-linked gelatin conduits enhance peripheral nerve regeneration.

Here we have evaluated peripheral nerve regeneration with a porous biodegradable nerve conduit (PGGC), which was made from genipin-cross-linked gelatin. To examine the effect of pores, nonporous genipin-cross-linked gelatin conduit (GGC) was considered as the control. Both the PGGC and the GGC were dark blue in appearance with a concentric and round lumina. The PGGC featured an outer surface with pores of variable size homogeneously traversing, and a partially fenestrated inner surface connected by an open trabecular meshwork. The GGC had a rough outer surface whereas its inner lumen was smooth. Both PGGCs and GGCs had similar hydrophilicity on condition of the same material and cross-linking degree. The porosity of PGGCs and GGCs was 90.8 +/- 0.9% and 24.3 +/- 2.9%, respectively. The maximum tensile force of the GGCs (0.12 +/- 0.06 kN) exceeded that of the PGGCs (0.03 +/- 0.01 kN), but the PGGCs had a higher swelling ratio than GGCs at 0.5, 1, 3, 6, 12, 24, 48, 60, 72, and 84 h after soaking in deionized water. Cytotoxic testing revealed the soaking solutions of both of the tube composites would not produce cytotoxicity to cocultured Schwann cells. After subcutaneous implantation on the dorsal side of the rat, the PGGC was degraded completely after 12 weeks of implantation whereas a thin tissue capsule was formed encapsulating the partially degraded GGC. Biodegradability of both of the tube groups and their effectiveness as a guidance channel were examined as they were used to repair a 10 mm gap in the rat sciatic nerve. As a result, fragmentation of the GGC was still seen after 12 weeks of implantation, yet the PGGC had been completely degraded. Histological observation showed that numerous myelinated axons had crossed over the gap region in the PGGCs after 8 weeks of implantation despite only few myelinated axons and unmyelinated axons mostly surrounded by Schwann cells seen in the GGCs. In addition, the regenerated nerves in the PGGCs presented a significantly higher nerve conductive velocity than those in the GGCs (P < 0.05). Thus, the PGGCs can not only offer effective aids for regenerating nerves but also accelerate favorable nerve functional recovery compared with the GGCs.