RISK FACTORS ASSOCIATED WITH CTS

CTS remains an idiopathic syndrome, but there are
certain risk factors that have been associated with this
condition. The most significant of these are environmental Carpal Tunnel Syndrome The Open Orthopaedics Journal, 2012, Volume 6 71
risk factors. Prolonged postures in extremes of wrist flexion
or extension, repetitive use of the flexor muscles, and
exposure to vibration are the primary exposures that have
been reported [40-43].
 Medical risk factors can be divided into four categories:
(1) extrinsic factors that increase the volume within the
tunnel (outside or inside the nerve); (2) intrinsic factors
within the nerve that increase the volume within the tunnel;
(3) extrinsic factors that alter the contour of the tunnel; and
(4) neuropathic factors.
 Extrinsic factors that can increase the volume within the
tunnel include conditions that alter the fluid balance in the
body. These include pregnancy, menopause, obesity, renal
failure, hypothyroidism, the use of oral contraceptives and
congestive heart failure [32].
 Intrinsic factors within the nerve that increase the
occupied volume inside the tunnel include tumours and
tumour-like lesions. Extrinsic factors that can alter the
contour of the tunnel could be the aftermath of fractures of
the distal radius, directly or via posttraumatic arthritis [32].
 Neuropathic factors, such as diabetes, alcoholism,
vitamin toxicity or deficiency, and exposure to toxins, can
play a role in eliciting CTS symptoms. This is because they
affect the median nerve without necessarily increasing the
interstitial pressure within the carpal tunnel [32]. In fact,
diabetic patients have higher tendency to develop CTS due
to lower threshold for nerve damage [4].