Mechanical Effects of a Specific Neurodynamic Mobilization of the Superficial Fibular Nerve: A Cadaveric Study.

CONTEXT: A specific neurodynamic mobilization for the superficial fibular nerve (SFN) has been suggested in the reference literature for manual therapists to evaluate nerve mechanosensitivity in patients. However, no authors of biomechanical studies have examined the ability of this technique to produce nerve strain. Therefore, the mechanical specificity of this technique is not yet established. OBJECTIVES: To test whether this examination and treatment technique produced nerve strain in the fresh frozen cadaver and the contribution of each motion to total longitudinal strain. DESIGN: Controlled laboratory study. SETTING: Laboratory. MAIN OUTCOME MEASURE(S): A differential variable reluctance transducer was inserted in 10 SFNs from 6 fresh cadavers to measure strain during the mobilization. A specific sequence of plantar flexion, ankle inversion, straight-leg raise position, and 30° of hip adduction was applied to the lower limb. The mobilization was repeated at 0°, 30°, 60°, and 90° of the straight-leg raise position to measure the effect of hip-flexion position. RESULTS: Compared with a resting position, this neurodynamic mobilization produced a significant amount of strain in the SFN (7.93% ± 0.51%, P < .001). Plantar flexion (59.34% ± 25.82%) and ankle inversion (32.80% ± 21.41%) accounted for the biggest proportions of total strain during the mobilization. No difference was noted among different hip-flexion positions. Hip adduction did not significantly contribute to final strain (0.39% ± 10.42%, P > .05), although high variability among limbs existed. CONCLUSIONS: Ankle motion should be considered the most important factor during neurodynamic assessment of the SFN for distal entrapment. These results suggest that this technique produces sufficient strain in the SFN and could therefore be evaluated in vivo for correlation with mechanosensitivity.

Normal range of motion at the hip show different pressure behavior in the lateral and acetabular compartments: a cadaveric investigation.

PURPOSE: The techniques used previously to assess intracapsular pressures did not allow the assessment of pressure variations in both compartments throughout the entire range of motion without puncturing the capsular tissue. Our hypothesis was that the intra-capsular pressure would be different in the lateral and acetabular compartment depending on the movement assessed. METHODS: Eight hip joints from four cadaveric specimens (78.5 ± 7.9 years) were assessed using intra-osseous tunnels reaching the lateral and acetabular compartments. Using injector adaptors, 2.7 ml of liquid were inserted in both compartments to simulate synovial liquid. Optic pressure transducers were used to measure pressure variations. We manually performed hip adduction, abduction, extension, flexion and internal rotation at 90° of flexion. RESULTS: Hip extension and internal rotation show the highest intra-capsular pressures in the lateral compartment with increases of 20.56 ± 19.29 and 19.27 ± 18.96 mmHg, respectively. Hip abduction and hip internal rotation showed depressurisations of - 16.86 ± 18.01 and - 31.88 ± 30.71 mmHg in the acetabular compartment, respectively. The pressures measured in the lateral compartment and in the acetabular compartment were significantly (P < 0.05) different for the hip abduction, 90° of flexion and internal rotation. Pressure variations showed that maximum intracapsular fluid pressures in the lateral compartment occur at maximum range of motion for all movements. CONCLUSION: As an increase in pressure may produce hip pain, clinician should assess pain at maximum range of motion in the lateral compartment. The pressure measured in the acetabular compartment vary depending on the hip position. The movements assessed are used in clinical practice to evaluate hip integrity and might bring pain. The pressure variations throughout the entire range of motion are a relevant information during hip clinical assessment and might help clinicians to better understand the manifestations of pain.

Intracapsular pressures in the flexion-abduction-external rotation and flexion-adduction-internal rotation tests and their comparison with classic hip range of motion: A cadaveric assessment.

Background Flexion-Abduction-External-Rotation and Flexion-Adduction-Internal-Rotation tests are used to reproduce pain at the hip during clinical assessment. As pain can be elicited by high intracapsular pressure, no information has been provided regarding intracapsular pressure during these pain provocative tests. Methods Eight hip joints from four cadaveric specimens (78.5 ± 7.9 years) were assessed using intra-osseous tunnels reaching the lateral and acetabular compartments. To simulate synovial liquid, 2.7 ml of liquid were inserted in both compartments using adaptor injectors. Optic pressure transducers were used to measure pressure variations. Pressures were compared between compartments in each test and between tests for each compartment. Both tests were compared with uniplanar movements. Findings The Flexion-Adduction-Internal-Rotation test showed a significant difference between pressure measured in the lateral (27.17 ± 42.63 mmHg) and acetabular compartment (-26.80 ± 29.26 mmHg) (P < 0.006). The pressure measured in the lateral compartment during the Flexion-Adduction-Internal-Rotation test (27.17 ± 42.63 mmHg) was significantly higher than in the Flexion-Abduction-External-Rotation test (-8.09 ± 15.09 mmHg) (P < 0.010). The pressure measured in the lateral compartment in the Flexion-Abduction-External-Rotation test was significantly lower than during internal rotation (P = 0.011) and extension (P = 0.006). Interpretation High intracapsular pressure is correlated with greater pain at the hip. Clinicians should assess pain with caution during the Flexion-Adduction-Internal-Rotation test as this test showed high intracapsular pressures in the lateral compartment. The Flexion-Abduction-External-Rotation is not influenced by high intra-capsular pressures.