Strain and excursion of the sciatic, tibial, and plantar nerves during a modified straight leg raising test

Abstract

A modified straight leg raising (SLR) in which ankle dorsiflexion is performed before hip flexion has been suggested to diagnose distal neuropathies such as tarsal tunnel syndrome. This study evaluates the clinical hypothesis that strain in the nerves around the ankle and foot caused by ankle dorsiflexion can be further increased with hip flexion. Linear displacement transducers were inserted into the sciatic, tibial, and plantar nerves and plantar fascia of eight embalmed cadavers to measure strain during the modified SLR. Nerve excursion was measured with a digital calliper. Ankle dorsiflexion resulted in a significant strain and distal excursion of the tibial nerve. With the ankle in dorsiflexion, the proximal excursion and tension increase in the sciatic nerve associated with hip flexion were transmitted distally along the nerve from the hip to beyond the ankle. As hip flexion had an impact on the nerves around the ankle and foot but not on the plantar fascia, the modified SLR may be a useful test to differentially diagnose plantar heel pain. Although the modified SLR caused the greatest increase in nerve strain nearest the moving joint, mechanical forces acting on peripheral nerves are transmitted well beyond the moving joint. ß

Heel Pain—Plantar Fasciitis

“…23 secondary ICD-10 codes and conditions associated with heel pain are G57.5 Tarsal tunnel syndrome and G57.6 Lesion of plantar nerve 23 Plantar fascial fibromatosis/Contracture of plantar fascia, -ate pathology of the plantar fascia, plantar nerves near the proximal plantar fascia, or tissues of the tarsal tunnel, are often overlapping because it is difficult to selectively load the tissues hypothesized to be the source of a patient's heel pain during physical examination 2 and treatment procedures. 11,38 fasciitis, tarsal tunnel syndrome, and plantar nerve lesions codes are b28015 Pain in lower limb and . G57.5 G57.6…”

Comparison of the Hamstring Muscle Length and Sciatic Nerve Tension among Computer Workers with Different Subtypes of Lower Back Pain

“…In our study, hamstring muscle length was significantly shorter in Group 2 than in Group 1. Tightness in the posterior thigh caused by an increase in sciatic nerve tension may also reduce hip motion 5,6) . Increased sciatic nerve tension has been shown to cause ischemia and hypoxia in nerve tissue or reduce axoplasmic flow, which can induce microtrauma in an adjacent muscle 13) .…”

“…The SLR with 15 to 20 degrees of ankle dorsiflexion, a modification of the SLR, has been used to measure sciatic nerve tension regardless of hamstring muscle length 5) . We performed the SLR and the modified SLR to test sciatic nerve tension using a digital inclinometer to measure sciatic nerve tension.…”

“…Many clinical researchers have suggested that the shortening of the hamstring muscles may affect static or dynamic postures of the pelvis and lumbar spine 3,4) . Increased sciatic nerve tension may also limit lumbar or hip motion 5) . Many researchers have provided information on categorizing LBP into more homogeneous subtypes for a heterogeneous LBP.…”

Current concepts in the diagnosis and management of extra-articular hip impingement syndromes

“…When the knee is flexed, the nerve moves posterolateral and the nerve moves deeply into the tunnel when the knee is extended. During a straight leg raise with knee extension, the sciatic nerve experiences a proximal excursion of 28 mm medial towards the hip joint [54]. Additionally, it has been reported that neurapraxia can be produced at 6% strain and that a complete block can occur at 12% strain [55].…”