Morphological and Functional Changes in the Diabetic Peripheral Nerve

Abstract

It has been hypothesized that in individuals with diabetes mellitus the peripheral nerve is swollen owing to increased water content related to increased aldose reductase conversion of glucose to sorbitol. It has further been hypothesized that the tibial nerve in the tarsal tunnel is at risk for chronic nerve compression related to this swelling. We used diagnostic ultrasound to evaluate this hypothesis. Cross-sectional areas of the tibial nerve were measured in diabetic patients with neuropathy and compared with previously reported measurements in nondiabetic patients and diabetic patients without neuropathy. We used the Pressure-Specified Sensory Device (Sensory Management Services LLC, Baltimore, Maryland) to document the presence of neuropathy in 24 diabetic patients (48 limbs). Previous studies have found that the cross-sectional area of the tibial nerve in nondiabetic patients and in diabetic patients without neuropathy is not significantly different. We found that the mean cross-sectional area of the tibial nerve in diabetic patients with neuropathy is significantly greater than that in diabetic patients without neuropathy (24.0 versus 12.0 mm(2)). Our study highlights the value of newer ultrasound imaging techniques in identifying morphological change in the tibial nerve and confirms that the tibial nerve in the tarsal tunnel is swollen, consistent with chronic compression, in diabetic patients with neuropathy.

Association of myelinated primary afferents impairment with mechanical allodynia in diabetic peripheral neuropathy: an experimental study in rats

“…Since peripheral nerves in diabetes are proven to be susceptible to mechanical compression [ 19 ], a modified rat model of chronic nerve compression, in which the diabetic sciatic nerve distal to the ischial notch was surrounded by a 1.5-cm length of latex tube [ 20 , 21 ], was used for this study. Nerve trunk swelling as diabetes is induced exposes the rat nerve to progressive chronic compression by the encircling latex tube, as occurs in human diabetes at known sites of fibro-osseous anatomic narrowings, such as carpal, cubital and tarsal tunnels [ 22 ].…”

Can Ultrasound of the Tibial Nerve Detect Diabetic Peripheral Neuropathy?

“…Peripheral nerve swelling in the setting of DSP presumably stems from increased water content as a byproduct of the aldose reductase conversion process of glucose into sorbitol (7). The sural nerve is one of the earliest nerves affected in diabetic neuropathy as a subclinical sensory nerve deficit on NCS (17) and is therefore routinely examined for diagnostic NCS purposes (18).…”

Preliminary Evaluation of the Sural Nerve Using 22-MHz Ultrasound: A New Approach for Evaluation of Diabetic Cutaneous Neuropathy

“…Several reports have focused on the use of ultrasound to evaluate nerve decompression in diabetic patients [16], [17]. Studies focusing on monitoring the morphological changes of the cutaneous nerves of diabetics by US have not been previously performed.…”