Objective Contact casting with plaster bandages is a standard technique for thoraco-lumbo-sacral orthosis (TLSO) fabrication. However, this hands-on process depends on the operator’s skill as well as requires a close physical contact, involving potential risks of coronavirus and influenza virus infection and the patient’s personal space violation. Recently, noncontact, highly accurate molding technology using 3-dimensional (3D) digital scanning has been developed. Although 3D scanning is widely applied for limb orthosis, its spinal application mainly focuses on pediatric scoliosis. Comparative studies across diverse body types remain limited. Therefore, this study aimed to clarify the adaptability, accuracy, and fabrication time of TLSO produced using noncontact 3D digital scanning, comparing with conventional contact plaster-bandage casting.
Methods TLSO was fabricated using both contact and noncontact techniques for mannequins with 4 different body types. High-precision scanner and computed tomography (CT) were used to assess the shape reproducibility by quantifying the gap area between the orthosis and mannequin. In addition, total fabrication time was compared between the 2 techniques.
Results High-precision scanner identified that 3D scanning showed a higher shape reproducibility than conventional casting, particularly in curvilinear areas (all p<0.001). In CT measurement, 3D scanning demonstrated a smaller gap area in all the body types (all p<0.001). Fabrication time was also shorter during 3D scanning (54.9±0.9 minutes) than during conventional casting (100.0±5.5 minutes) (p<0.001).
Conclusion Noncontact 3D digital scanning facilitates a rapid, accurate, and reproducible TLSO fabrication across diverse body types, providing a safer and more efficient alternative to conventional contact plaster-bandage casting.
Objective Transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel, has been implicated in intervertebral disc homeostasis; however, its role in autophagy regulation remains unclear. This study aimed to investigate whether agonist-induced TRPV4 activation promotes autophagy and extracellular matrix (ECM) synthesis in rat intervertebral discs.
Methods In vitro, rat nucleus pulposus (NP) cells were treated with the TRPV4 agonist (GSK1016790) under normal, serum-deprived, or interleukin-1β-stimulated conditions. Cell viability, intracellular Ca2+ influx, adenosine monophosphate-activated protein kinase/mammalian target of rapamycin (mTOR) (AMPK/mTOR) pathway, autophagy, ECM metabolism, apoptosis, and senescence were evaluated. In vivo, TRPV4 agonist was injected into the caudal discs subjected to temporary static compression, and disc changes were assessed by radiography, histomorphology, and immunofluorescence.
Results In vitro, agonist-induced TRPV4 activation rapidly increased intracellular Ca2+ influx and enhanced AMPK phosphorylation. A noncytotoxic concentration of the TRPV4 agonist (10 nM) was selected after dose-response testing. Under the inflammatory stress, TRPV4 agonist enhanced autophagy, promoted ECM synthesis, and suppressed apoptosis and senescence, leading to improved NP cell viability. In vivo, TRPV4 agonist treatment preserved radiographic disc height (p<0.01), reduced histomorphological degeneration (p<0.01), and increased expression of COL2A1, Brachyury, p-AMPK (phosphorylated AMPK), and autophagy markers (p<0.01) compared with controls.
Conclusion These findings demonstrated that TRPV4 activation promotes autophagy and ECM synthesis via the AMPK/mTOR pathway in rat discs and attenuates stress-induced degeneration, suggesting TRPV4 as a potential therapeutic target for disc degeneration.
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