ABSTRACT
Various modalities to facilitate nerve regeneration have been described in the literature with limited success. We hypothesized that negative pressure applied to a sectioned peripheral nerve would enhance nerve regeneration by promoting angiogenesis and axonal lengthening. METHODS: Wistar rats' sciatic nerves were cut (creating ~7 mm nerve gap) and placed into a silicone T-tube, to which negative pressure was applied. The rats were divided into 4 groups: control (no pressure), group A (low pressure: 10 mm Hg), group B (medium pressure: 20/30 mm Hg) and group C (high pressure: 50/70 mm Hg). The nerve segments were retrieved after 7 days for gross and histological analysis. RESULTS: In total, 22 rats completed the study. The control group showed insignificant nerve growth, whereas the 3 negative pressure groups showed nerve growth and nerve gap reduction. The true nerve growth was highest in group A (median: 3.54 mm) compared to group B, C, and control (medians: 1.19 mm, 1.3 mm, and 0.35 mm); however, only group A was found to be significantly different to the control group (**P < 0.01). Similarly, angiogenesis was observed to be significantly greater in group A (**P < 0.01) in comparison to the control. CONCLUSIONS: Negative pressure stimulated nerve lengthening and angiogenesis within an in vivo rat model. Low negative pressure (10 mm Hg) provided superior results over the higher negative pressure groups and the control, favoring axonal growth. Further studies are required with greater number of rats and longer recovery time to assess the functional outcome.
ABSTRACT
The potential of peripheral nerves to regenerate under the effect of axial tensile forces was not previously extensively explored due to the lack of capabilities of translating ex vivo axonal stretch-growth to in vivo studies, until the development of a nerve stretcher. The nerve stretcher, which we have designed and manufactured recently, is a device that uses a controlled amount of axial tensile force (vacuum/negative gauge pressure) applied directly to a sectioned peripheral nerve in vivo to expedite nerve regrowth rate. Using this platform, a series of experiments was carried out to observe the effect of in vivo axial stretch on axonal lengthening. During these experiments, a few challenges necessitated redesigning the device like a sudden loss of stretching force due to vacuum leakage, erroneous feedback from vacuum sensor due to sensor drift, and inability to control and operate the device remotely. Here we present an improved design of the nerve stretcher along with its integration with a state-of-the-art online vacuum monitoring facility to control, collect, process, and visualize negative gauge pressure data in real-time.
ABSTRACT
Peripheral nerve injuries are relatively common and can be caused by a variety of traumatic events such as motor vehicle accidents. They can lead to long-term disability, pain, and financial burden, and contribute to poor quality of life. In this review, we systematically analyze the contemporary literature on peripheral nerve gap management using nerve prostheses in conjunction with physical therapeutic agents. The use of nerve prostheses to assist nerve regeneration across large gaps (> 30 mm) has revolutionized neural surgery. The materials used for nerve prostheses have been greatly refined, making them suitable for repairing large nerve gaps. However, research on peripheral nerve gap management using nerve prostheses reports inconsistent functional outcomes, especially when prostheses are integrated with physical therapeutic agents, and thus warrants careful investigation. This review explores the effectiveness of nerve prostheses for bridging large nerve gaps and then addresses their use in combination with physical therapeutic agents.
