Effect of surgical decompression of nerves in the lower extremity in patients with painful diabetic polyneuropathy on stability: a randomized controlled trial.

OBJECTIVE: To investigate the effect of decompression of nerves in the lower extremity in patients with painful diabetic polyneuropathy on static balance using a sensitive pressure mat system. DESIGN: Non-blinded randomized controlled trial. SETTING: Single center study performed at the University Medical Center Utrecht between 2010-2013. SUBJECTS: Patients with painful diabetic polyneuropathy assessed with the Diabetic Neuropathy Symptom score and Diabetic Neuropathy Examination between 18-90 years. Exclusion criteria were: physical problems leading to instability, BMI>35 kg/m2, ankle fractures in history, amputations proximal to the tarsometatarsal joints, active foot ulcer(s), severe occlusive peripheral vascular diseases. INTERVENTION: Unilateral surgical nerve decompression at four sites in the lower extremity, the contralateral limb was used as control (within-patient comparison), with one year follow-up. MAIN MEASURES: Preoperatively and 6 and 12 months postoperatively, weight bearing and five variables of sway of the center of pressure were measured with a pressure mat with eyes open and eyes closed. T-test was used for evaluation of postoperative results. RESULTS: Thirty-nine Patients met inclusion criteria and were enrolled for stability testing. Postoperatively no significant differences for sway variables and weight bearing were seen compared to preoperatively measurements. CONCLUSIONS: There is no evidence that surgical decompression of nerves of the lower extremity influences stability within one year after surgery in patients with painful diabetic polyneuropathy.

Optimization of Surgical Outcome in Lower Extremity Nerve Decompression Surgery.

BACKGROUND: There is still debate regarding whether the surgical release of entrapped lower extremity nerves reduces complaints of associated neuropathy and results in gain of sensory function. The aim of this study was to investigate which factors are associated with a favorable surgical outcome, by follow-up of patients previously participating in a randomized controlled trial. METHODS: The authors evaluated the 5-year follow-up of diabetic patients previously participating in the Lower Extremity Nerve Entrapment Study (LENS). Visual analogue pain scores, satisfaction, complaints, quality of life (i.e., 36-Question Short-Form Health Survey and EuroQol 5 Dimensions instrument), sensory function, and incident ulceration and amputation were assessed. Differences between patients who underwent unilateral versus bilateral decompressions were investigated. RESULTS: Thirty-one of the original 42 LENS participants were measured, of which eight patients underwent additional decompression of the contralateral leg, after 12-month LENS follow-up. At 5 years, bilateral surgical patients (n = 8) had significantly lower pain scores and higher quality of life compared with unilateral surgical patients (n = 23), were younger, had a lower age when diagnosed with diabetes, and had a lower body mass index at baseline. Pain scores of the additional decompressed leg decreased in a manner similar to that of the initial decompressed leg during follow-up. Patients with severe preoperative sensory loss did worse; 41.2 percent of the LENS Follow-Up Study subjects underwent or considered undergoing contralateral surgery. CONCLUSION: The authors' results suggest that the beneficial effects of lower extremity nerve decompression surgery are reserved for a select group of patients, of which preoperative nerve damage, age, duration of diabetes, and body mass index are important effect modifiers. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Nerve conduction studies after decompression in painful diabetic polyneuropathy.

PURPOSE: To investigate the influence of nerve decompression at potential entrapment sites in the lower extremity in painful diabetic polyneuropathy on nerve conduction study variables. METHODS: Forty-two patients with painful diabetic polyneuropathy were included in this prospective randomized controlled trial. Preoperative nerve conduction studies were performed bilaterally. Each patient underwent unilateral surgical decompression of the tibial nerve and common, superficial, and deep peroneal nerves. The contralateral side was used as a control: within-patient comparison. One year postoperatively, the nerve conduction studies were repeated. Univariate paired sample T-tests and a multivariate analysis of variance were performed to compare data. RESULTS: In univariate analysis of the peroneal nerve, the distal compound muscle action potential amplitude measured at the extensor digitorum brevis muscle of the intervention legs decreased significantly, as did the area drop measured at the extensor digitorum brevis muscle of the control legs. The distal motor latency measured at the extensor digitorum brevis muscle of the intervention legs increased significantly, as did the distal compound muscle action potential amplitude measured at the anterior tibial muscle of the control legs. For the tibial nerve, the distal compound muscle action potential duration decreased significantly in the control legs. The multivariate analysis showed no significance overall. CONCLUSIONS: Decompression of nerves of the lower extremity in patients with painful diabetic polyneuropathy has no beneficial effect on nerve conduction study variables 12 months after surgery.

Ultrasound findings after surgical decompression of the tarsal tunnel in patients with painful diabetic polyneuropathy: a prospective randomized study.

OBJECTIVE: It has been hypothesized that the development of diabetic polyneuropathy (DPN) is due to swelling of the nerve, as well as thickening and stiffening of the surrounding ligaments, causing chronic compression of nerves. We aimed to examine the effect of surgical decompression of the tibial nerve on the mean cross-sectional area (CSA). RESEARCH DESIGN AND METHODS: We performed a randomized controlled trial of 42 subjects with painful DPN diagnosed using the Diabetic Neuropathy Score. A computer randomized for the surgery arm of the study. A control group consisting of 38 healthy subjects was included. An experienced sonographer measured the CSA and thickness-to-width (T/W) ratio of the tibial nerve, as well as the thickness of the flexor retinaculum. RESULTS: CSA is significantly larger in patients with painful DPN (8.4 ± 3.9 mm(2)) than in control subjects (6.4 ± 1.3 mm(2)), P = 0.007. The T/W ratio in patients with painful DPN is 0.64 and in control subjects 0.59, P = 0.03. Patients with DPN have a significantly thicker retinaculum (1.07 mm) than control subjects (0.84 mm), P < 0.001. Mean follow-up was 28.2 weeks (range 23-45). Difference between baseline and follow-up in the operated leg was 1.49 mm(2) and in the control leg 1.81 mm(2), P = 0.674. CONCLUSIONS: Decompression of the tibial nerve does not result in a significant difference between baseline and follow-up in CSA using ultrasound between the operated and control leg. Ultrasound measurements show a significantly increased CSA, a significantly thicker retinaculum, and a significantly increased T/W ratio in patients with painful DPN compared with healthy control subjects. Clinical trial reg. no. NTR2344, www.trialregister.nl.