A Systematic Review of Carpal Tunnel Syndrome (CTS) Outcomes in the Presence of Cervical Radiculopathy (CR) or Thoracic Outlet Syndrome (TOS)

Background and/or Objectives: The main objective was to systemically review and compare treatment outcomes in patients with carpal tunnel syndrome (CTS) with or without coexisting cervical radiculopathy (CR) or thoracic outlet syndrome (TOS), commonly referred to as Double Crush Syndrome (DCS).

Design: A broad search strategy was conducted in PubMED and Cochrane Library databases using linked terms of CTS with TOS or CR. Filters for full-text, English-language studies, yielding a total of 188 articles. After removing 5 duplicate studies and narrowing to studies published between 2000 and 2025, 93 studies remained. Using a PICO framework - Population: adults with CTS; Intervention: presence of CR or TOS in addition to CTS; Comparison: isolated CTS; Outcomes: functional outcomes or treatment failure - Non-human studies and those not meeting criteria were excluded. Screening was done manually and cross-checked using ChatGPT for consistency and bias reduction.

Setting : Academic

Participants : 188 articles.

Interventions: Not applicable.

Main Outcome Measures: Not applicable.

Results: Two retrospective cohort studies met inclusion criteria, including a total of 237 adult participants: 133 with isolated CTS and 104 with CTS plus CR (DCS).

Conclusions: The limitations in this literature review are the small number of retrospective studies with a lack of randomized clinical controlled trials, leading to potential selection bias and blinding. Discrepancy in diagnostic criteria for CR and differences in outcome measurement tools reduced comparability. Sample sizes limited statistical power to detect significant differences between groups. Additionally, no studies addressed TOS, limiting generalizability to all forms of DCS. Despite these limitations, the results suggest that CR does not significantly worsen outcomes in patients undergoing carpal tunnel release. This challenges the assumption that proximal nerve compression predicts poorer outcomes. However, given the methodological weaknesses and limited scope of existing data, larger prospective studies are necessary to confirm these findings.