Peripheral neuropathy (PN) commonly accompanies diabetes, reducing sensation in the legs and feet. This disabling nerve dysfunction can be due to compression of swollen nerves at entrapment sites: fibular neck (common peroneal n.), tarsal tunnel (tibial n.), and dorsum of the foot (deep peroneal n.). Surgical nerve decompression releases pressure on the nerve and restores nerve function.
PURPOSE: Previous research on this procedure has been limited to subject-reported sensation and function. This case study reports changes in sensory and physical function after bilateral triple nerve decompression in a PN patient.
METHODS: Subject: 59 yr-old woman with disabling diabetic PN. Measures taken before surgery and after full recovery: reported sensation/function, measured sensation, immediate post-release changes in intraoperative motor-evoked potentials (MEP) via nerve stimulation, functional reach, timed single leg standing balance (vision, no vision), max step length, rapid stepping, stair climb, four-square step test, gait speed.
RESULTS: The subject reported (visual analog scale, 0-10) improvements in numbness (9-5), pain (10-5), burning (9-4), tingling (10-5), instability (10-2), and weakness (10-3). Pooled across four foot sites, the pressure threshold to detect one- and two-point stimuli improved by 51.6 g/mm2 (76.8 to 25.2) and 56.8 g/mm2 (105.0 to 48.2), respectively. Common peroneal MEP amplitude improved by 7986 μv and 685 μv in the left and right leg, respectively. Functional reach increased 139%. Right leg balance increased by 20.4s with vision (5.8s to 26.2s) and 2.9s without vision (1.5s to 4.4s). Left foot balance increased by 3.4s with vision (0.4s to 3.8s) and 0.6s without vision (1.3s to 1.9s). Maximal step length with the left and right foot increased 72.7% and 86.7%, respectively. Rapid stepping on the left and right foot improved 13.5% and 30.3%, respectively. Preferred treadmill speed increased from 0.3m/s to 0.45m/s. 4m gait speed improved from 0.71m/s to 0.99m/s. Stair climb improved 63% (50.2s to 18.4s). Four-square stepping improved 46% (11.9s to 6.2s).
CONCLUSIONS: The consistent, positive improvements in functional task performance suggest improved lower limb function, presumably due to the regained sensation in the lower limb.
Funded by the Poudre Valley Foot and Ankle Clinic