INFLUENCE OF NEURAL TENSION IN MECHANICAL NOCICEPTIVE THRESHOLDS (MNTS) OF UPPER TRAPEZIUS MUSCLE

Abstract

Physiotherapists have developed examination techniques known as ‘neural tension tests’ to assess the mechanosensitivity of the major nerve trunks. Changes in neural tension provoked by these tests may alter the nociceptive responses of nearby tissues.

The aim of our study was to evidence changes in mechanical nociceptive thresholds (MNTs) of upper trapezius muscle in different neurodynamic positions.

Cross-sectional study. Fifty asymptomatic volunteers were evaluated with algometer in four neurodynamic positions:

1. Contralateral side-lying position with knees at 90° of flexion, hips at 70° of flexion and spine in neutral;

2. initial position with the homolateral knee in complete extension to add neural tension of sciatic nerve;

3. initial position with the homolateral knee in complete flexion to add neural tension of femoral nerve;

4. In supine position to add neural tension of median nerve using the Upper Limb Neurodynamic Test 1.

One physiotherapist (PT) measured MNTs unilaterally over TrPs1. Three consecutive measurements was evaluated in the four described positions, a second PT reported the data in kilograms (kg). A third PT was responsible for modifying subjects positions.

The findings revealed significant mean differences (SMD) in algometry measurements (P < 0.0001) between position 1 (mean 2.880 kg; SD 1.012 kg) and position 3 (mean 2.522 kg; SD 0.87 kg), SMD (P < 0.01) between position 1 and position 4 (mean 2.616 kg; SD 0.968 kg). No SMD between position 1 and 2 (mean 2.728 kg; SD 1.103 kg) (P < 0.08) and between positions 3 and 4 (P < 0.378).

We concluded that MNTs of upper trapezius muscle decrease with neural tension positions. MNTs decrease is similar with crural nerve and median nerve tension positions. So, neurodynamic positions are important procedures to be taken into account in clinical reasoning, both physical therapy diagnosis and treatment.