551 Bilateral Carpal Tunnel Syndrome Following AstraZeneca (AZD1222) COVID-19 Vaccination: A Case Report

Covid-19 infections correlate with peripheral neuropathy. Correlations extend to vaccination, with reports of polyradiculoneuropathy. We report a case of a 59-year-old right-hand dominant female presenting with bilateral carpal tunnel syndrome (CTS) nineteen days after AZD1222.

BSSH diploma-qualified hand surgeon assessment identified increasing median nerve (MN) paraesthesia and upper limb pain. Symptoms occurred post-AZD1222 second dose administered 12-weeks after the first. Past medical history was unremarkable, and she had not contracted Covid-19. Examination found severe CTS-signs: thenar weakness, positive provocative tests (Phalen's and Tinel's) and 8mm MN static 2-point discrimination. Electrophysiology confirmed very severe wrist bilateral median neuropathies, with no evidence of widespread peripheral neuropathy. Left carpal tunnel decompression found a swollen MN bulging through the transverse carpal ligament. The patient reported symptom improvement 2 weeks post-operatively.

This was reported using MHRA “yellow card” protocols as symptoms occurred within the period of neuropathic side effects. Proposed neuropathy mechanisms in Covid-19 include vasa nervorum microangiopathy. Post-vaccine effects could be connected to such changes in microcirculation implicated in CTS. Vaccines containing SARS-CoV-2 antigens enhance autoimmunity and may cause antibody-mediated effects on the synovial sheath, worsening symptoms in pre-existing CTS. Though we do not claim causality, emerging post-vaccination effects may include exacerbation. It is not uncommon for clinicians to diagnose CTS in patients with symptoms overlooked until an inciting event. With Covid-19 ‘boosters' the long-term strategy, vaccinations may increase neuropathy contribution. Increasing caseloads may present future challenges to hand surgeons managing CTS. Recording correlations may provide a basis for investigating CTS pathophysiology post AZD1222.

T2-weighted MRI defines critical compression in the distal carpal tunnel that is relieved after decompressive surgery

Introduction

Despite Carpal Tunnel Syndrome (CTS) being the most common entrapment neuropathy, its pathophysiology remains debated. Sub-synovial connective tissues (SSCT) within the carpal tunnel are thought to play a role but are poorly characterised. MRI analysis offers potentially novel insights into SSCT characteristics.

Methods

A pilot study of T2-weighted MRI was performed in healthy controls (n=7), and in CTS patients (n=16) pre- and 6 months post-surgical decompression. Image analysis was performed to quantify SSCT cross-sectional area, SSCT signal intensity ratio, and wrist index (depth/width) at distal, middle and proximal wrist landmarks.

Results

Median SSCT signal intensity was lower in the distal carpal tunnel of CTS patients pre-operatively (0.96) compared to controls (1.13; P = 0.008) and normalised post-operatively (1.13, P = 0.001). Median wrist index was also lower in CTS patients pre-operatively (0.60) compared to controls (0.67, P = 0.022), and again normalised post-operatively (0.74, P =0.001). This was attributed to changes in carpal depth in the antero-posterior axis with decompression surgery.

Conclusion

This pilot study successfully demonstrated MRI assessment of SSCT in patients with CTS. The decreased SSCT signal intensities suggest predominant changes at the distal tunnel, potentially indicating reduced SSCT perfusion pre-surgery which normalised post-surgery. Our preliminary findings merit further investigation in a larger cohort.

562 Home Microsurgical Method: A Zero-Cost, Accessible, Simulator Using Home-Based Technologies

Microsurgery is an advanced practice that demands a steep learning curve. Skill acquisition is reliant on repetition which is challenging with decreased trainee operating hours. Evidence indicates early skill acquisition in low-fidelity simulation is of equal efficacy to operating time. Our aim was to create a zero-cost, low-fidelity, microsurgery simulator using home-based technology.

The simulator has five components; a smartphone (iPhone/Android), laptop/computer, USB/lightning wire, ruler, and two supports of equal height. The ruler creates a platform between the supports on which to place the phone, camera focused downwards. The phone camera captures the surgical field between the supports, projecting the image onto the laptop screen via the USB connection.

The trainee operates in a ‘hands down, eyes up’ fashion, looking forwards at the laptop/computer screen whilst operating below in the field of the camera. Latest smartphones achieve magnifications equivalent to a microscope, preserving image quality whilst allowing recording of sim tasks for technical review.

Initial verbal feedback in informal advisory groups has been resoundingly positive. There is clear educational benefit with potential to work with consultant surgeons to develop free, accessible, online training modules. These would provide structured, remote, platforms for both qualitative and quantitative tracking of skill development.