Development of novel diagnostic and therapeutic methods for carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common compression mononeuropathy and the most common disorder of the median nerve (MN), with an incidence of 3-4 % and prevalence of 13 %. Unfortunately, current diagnostic and therapeutic approaches remain significantly limited in many respects. Accordingly, to optimize diagnostic and treatment outcomes in CTS, we aim to explore three compelling unanswered questions: 1) Can dynamic US of the MN provide additional information and raise diagnostic accuracy in CTS patients? 2) Does a dextrose injection provide superior alternative to corticosteroids in regard to treatment outcome and side effects in CTS patients? 3) Does the US-guided minimally invasive carpal tunnel release (CTR) provide improved MN mobility? 4) Does injection treatment or minimally invasive CTR have an effect on morphometric and structure characteristics of MN? With advancements in high-resolution ultrasound (HRUS) technology, US has become a gold standard for peripheral nerve imaging, with excellent spatial resolution and potential for dynamical imaging. Although diagnosis of CTS using US and nerve conduction studies represents the current standard, the literature consistently indicates the need for more detailed and exact diagnostic approaches. A potential of dynamic MN evaluation with US has been demonstrated, but due to methodological differences, significant inconsistencies exist among few published studies. Prior studies used computational methods presuming that the nerve is a homogenous entity that moves en bloc. However, the nerve structure is in- homogenous with complex fascicular anatomy and the motion is not necessarily uniform. An improved and well-validated method is therefore imperative to raise the diagnostic accuracy of US imaging for CTS. A standard treatment for CTS is surgical release, and an established alternative in mild and moderate CTS is local corticosteroid injections. Both treatments however offer suboptimal mid- to long-term patient outcome. Given the important potential complications of surgical treatment and the broad-spectrum side effects of corticosteroid use, further improvements in minimally invasive techniques and medication options are needed. Recently, US-guided perineural MN dextrose injection was shown to be more effective than US-guided corticosteroid injection in mild-to-moderate CTS at 6 months. However, a larger randomised control trial is needed to verify this promising result over a longer duration. HRUS-guided minimally invasive techniques of CTR are becoming of extreme importance, since they permit continuous intraoperative surveillance with reduced hazard of structural damage, enable faster postoperative recovery with early return to daily activities and result in reduced incision scar and decreased overall treatment expenses. HRUS-guided minimally invasive technique is a novel technique that needs further clinical data on the outcome. Due to its access, the HRUS-guided minimally invasive offers important advantage over other thechniques of carpal tunnel release as it allows HRUS examination during as well as imediately after carpal tunnel release. The proposed project aims to accomplish three broad objectives. First, it will provide a novel tool for dynamic US analysis that will enable radiologist to visualize and measure motion of individual layers of longitudinal structures and quantify their deformations, a tool that could substantially improve diagnostic capabilities of US imaging in CTS patients. Second, it will clarify whether US-guided dextrose injection provides a superior alternative to corticosteroid injections in regard to treatment outcome and side effects in CTS patients. Third, it will provide in depth understanding the effects of the CTR on MN. Please note that in Slovenia alone there are at least 60.000 people affected by CTS and the proposed work will have an important impact on optimal clinical pathway development for CTS patients.