Sonographic Evaluation of Sciatic Nerves in Patients With Unilateral Sciatica

Neuromuscular ultrasound changes in unilateral symptomatic subacute lumbosacral radiculopathy: A prospective simple blinded cohort study

INTRODUCTION/AIMS

Lumbosacral radiculopathy (LR) is a common disorder. Neuromuscular ultrasound (NMU) is a rapidly evolving technique for the investigation of peripheral nerve and muscle disorders, but studies using NMU in LR are lacking. The aim of the present study was to investigate ultrasonographic neuromuscular changes distant from root compression in patients with subacute to chronic compressive LR with motor impairment.

METHODS

Patients with unilateral subacute to chronic L4, L5, or S1 radiculopathy with motor impairment and confirmed by magnetic resonance imaging were included. The sciatic and femoral nerve cross-sectional areas (CSA), the CSA of lower limb muscles, and muscle fasciculation detection rate were assessed using a pre-specified neuromuscular ultrasound evaluation with blinded side-to-side comparison.

RESULTS

Of the 18 included patients, 66% were male and the mean age was 51 years. Overall, 16.7% had L4, 55.5% L5, and 27.8% S1 radiculopathy, mostly due to disc herniation (83%). Sciatic nerve CSA of the symptomatic side was increased (61.4 mm2 vs. 51.3 mm2; p = .001), and the fasciculation detection rate was higher in the affected muscles (delta = 13%, p = .007) compared to unaffected ones. Muscle CSA in affected and nonaffected muscles was decreased on the symptomatic side.

DISCUSSION

NMU evaluation in patients with symptomatic subacute to chronic LR revealed sciatic nerve enlargement distant from nerve root compression and higher fasciculation rates. These structural findings on NMU might be due to an axonal repair mechanism and an inflammatory response with endoneurial edema induced by ongoing nerve damage and potentially reflect progressive axonal loss.

Piriformis syndrome

Piriformis syndrome is a condition that is proposed to result from compression of the sciatic nerve, either in whole or in part, in the deep gluteal space by the piriformis muscle. The prevalence of piriformis syndrome depends upon the diagnostic criteria being used and the population studied but is estimated by some to be 5%-6% in all cases of low back, buttock, and leg pain and up to 17% of patients with chronic low back pain. While the sciatic nerve may pierce the piriformis muscle in about 16% of healthy individuals, this frequency is no different in those with the syndrome; thus, the relationship to this anatomic finding is unclear. The most common symptoms are buttock pain, external tenderness over the greater sciatic notch, and aggravation of the pain through sitting. Many clinical signs are reported for piriformis syndrome, but the sensitivity and specificity are unclear, in part because of the lack of a uniformly accepted case definition. In the majority of cases in the literature, it appears that the diagnosis is more ascribed to a myofascial condition rather than a focal neuropathy. Electrodiagnostic studies can be useful to exclude other causes of symptoms, but there is no well-accepted test to confirm the presence of piriformis syndrome. Ultrasound imaging may show thickening of the piriformis muscle, but further research is required to confirm that this is correlated with the clinical diagnosis. Magnetic resonance imaging and neurography may hold promise in the future, but there are not yet sufficient data to support adopting these methods as a standard diagnostic tool. The initial treatment of piriformis syndrome is typically conservative management with the general rehabilitation principles similar to other soft tissue musculoskeletal conditions. Local anesthetic, botulinum toxin, and/or corticosteroid injections have been reported by some to be beneficial for diagnostic or treatment purposes. Surgical interventions have also been used with variable success.

Regenerative medicine for neuropathic pain: physiology, ultrasound and therapies with a focus on alpha-2-macroglobulin

The currently available drugs to treat neuropathic pain do not provide adequate pain management. As such, other treatments including stem cells, platelet-rich plasma and plasma-derived molecules such as alpha-2 macroglobulin (A2M) are being explored because they show promising potential for neuropathic pain. The various mechanisms and immunomodulatory effects could be a desirable approach in targeting neuropathic pain. This review indicates that A2M can be highly efficacious due to its conformational change during activation and specificity of action on various cytokines. Its ability to reduce neuropathic pain can further the future of neuropathic intervention. However, there is a lack of robust clinical studies and thus further research is needed to verify and expand the understanding of its therapeutic effects.

Assessment of lower limb peripheral nerves with ultrasound in patients with traumatic amputation

Objectives

This study aims to assess the sciatic nerve (SN), common peroneal nerve (CPN), and tibial nerve (TN) by ultrasound in patients with traumatic lower limb amputation (LLA) and to examine the possible relationship between ultrasonographic and clinical findings.

Patients and methods

This cross-sectional study included a total of 33 male patients (mean age: 36.6±8.7 years; range, 21 to 48 years) who had LLA due to traumatic injury between May 2019 and April 2020. Amputation and prosthesis use and functional K level of activity were recorded. Ultrasound examinations were performed to measure the cross-sectional areas (CSAs) of the SN, CPN, and TN bilaterally at the same levels. The values from the normal sides were accepted as controls.

Results

The CSA values were greater on the amputated sides than the non-amputated sides for SN (p=0.001), TN (p=0.001), and CPN (p=0.015), regardless of the activity level. The amputated side SN (p=0.001), TN (p=0.001), and CPN (p=0.016) were thicker in patients with level of K4 activity than the non-amputated side. For the patients with K3 activity level, larger TN CSA values were determined on the amputated side, compared to those at the K4 level (p=0.035). The SN was found to be greater in patients using microprocessor-controlled knee prosthesis (p=0.032) and TN was larger in hypobaric sealing membrane users on the amputated sides (p=0.041).

Conclusion

The SN, CPN, and TN were found to be larger in all patients on the amputated sides and in patients with K4 activity level. Based on these findings, the K3 activity level and the use of hypobaric sealing membrane seems to affect the CSA values of TN. Additionally, the use of microprocessor knee prosthesis affects the CSA values of SN. We believe that these results may be essential for the analysis or prediction of lower extremity nerve involvement according to the K activity level and the use of prosthesis in patients with traumatic LLA.

Neuropathic Pain and Ultrasonography: A Multiperspective Literature Evaluation

Among the tools useful for the management of neuropathic pain, ultrasound presents several advantages, shown by the literature. We assessed the scientific production about neuropathic pain and ultrasound from different points of view: general topics, journal categories, geographical origin and lexical analysis. We searched papers on PubMed using the Medical Subject Headings "neuropathic pain" AND "ultrasound". We collected data about the journals where the papers were published, the country of the affiliation of the first author. For the lexical analysis, we evaluated the presence of selected words in the papers, and we built a graph representing the connections among words and papers. The papers were focused on the use of ultrasound as a diagnostic tool and guide for the therapy, assessing its application in different diseases such as Morton's neuroma and piriformis syndrome. The most represented journal category was anesthesia while the most common country the United States of America. The lexical analysis confirmed the importance of ultrasound for diagnosis of specific disease and treatment of pain. The described approaches provide a multiperspective evaluation of the literature and may support the interpretation of the information contained by the papers.

Ultrasonography Findings in the Proximal Sciatic Nerve and Deep Gluteal Muscles in 29 Dogs With Suspected Sciatic Neuritis

The present study aimed to describe the ultrasonography technique and analyze the ultrasonographic findings of the proximal sciatic nerve and deep gluteal muscles in dogs with suspected sciatic neuritis. The records of 29 dogs that underwent musculoskeletal ultrasound of the sciatic nerve and deep gluteal muscles were retrospectively evaluated. Both right and left sides were evaluated. Abnormal findings were unilateral in 28/29 (97%) of the dogs. The muscles examined included the piriformis muscle, gemelli muscles, internal obturator muscle, and medial gluteal muscle. Data included signalment, purpose of the dog, orthopedic examination findings, lameness examination findings, other diagnostic imaging findings, and ultrasonography findings. Irregular margins of the sciatic nerve were recorded in 76% of the dogs. The diameter of the sciatic nerve on the affected limb was significantly larger than the nerve on the contralateral, unaffected side (p < 0.00001). The mean ± standard deviation (SD) of the sciatic nerve inner diameter between the unaffected and affected limbs was 15 ± 14.66%. The mean ± SD in sciatic nerve outer diameter was 12 ± 7.71%. Abnormal ultrasonographic findings in at least one of the examined muscles were found in 28/29 (97%) of the dogs and included changes in echogenicity in 28/29 (97%) of the dogs, loss of detail in muscle fiber pattern in 5/29 (17%) of the dogs, and impingement between the sciatic nerve and piriformis muscle in 6/29 (21%) of the dogs. The most common underlying diagnosis was lumbosacral stenosis in 9/29 (31%) of the dogs. The most common sport was agility for 21/29 (71%) of the dogs. Repetitive jumping may predispose to both lumbosacral disease, through dynamic compression, and changes within the piriformis muscle, due to overuse of the muscle leading to irritation to sciatic nerve. Ultrasonography is considered a safe and non-invasive diagnostic method to evaluate the sciatic nerve and deep gluteal muscles of dogs, and provides additional guidance for diagnostics and rehabilitation planning. This is the first study documenting ultrasonography findings in a case series of the sciatic nerve and deep gluteal muscles and their pathology in dogs.

Shear Wave Elastographic Investigation of the Immediate Effects of Slump Neurodynamics in People With Sciatica

OBJECTIVES

Neurodynamic techniques are often used to treat people with sciatica pain, but their mechanical effects on the sciatic nerve are unknown. Shear wave elastography (SWE) has been shown to effectively estimate the stiffness of peripheral nerves in real time. The aim of this study was to use SWE to assess the effects of slump neurodynamics in the sciatic stiffness of people with sciatica.

METHODS

Sixteen participants volunteered for this study. The sciatic stiffness of 8 patients with unilateral chronic sciatica and 8 healthy control participants was measured by SWE, with the participants in a prone position and during a dynamic condition (ie, ankle dorsiflexion). These measurements were performed before and immediately after the neurodynamic intervention, which consisted of a static slump position applied to the symptomatic limb of the patients with sciatica and in a randomly chosen limb of the healthy participants.

RESULTS

The 8 patients with sciatica included 6 male and 2 female patients, and the 8 healthy control participants included 5 male and 3 female volunteers. Slump neurodynamics resulted in an immediate decrease in the sciatic nerve stiffness of the symptomatic limb in people with sciatica by 16.1% (effect size = 0.65; P = .019). The intervention showed no significant changes in the sciatic nerve stiffness of the healthy participants (effect size = 0.05; P = .754).

CONCLUSIONS

Slump neurodynamics have the potential of decreasing the sciatic nerve stiffness in people with sciatica, and this effect can be quantified by SWE, which may provide valuable information for health professionals.

The relationship of the shear wave elastography findings of patients with unilateral lumbar disc herniation and clinical characteristics

Background

The aim of this study was to find out whether the shear wave elastography (SWE) findings of patients with unilateral lumbar disc herniation (LDH) were related to clinical characteristics.

Methods

For this purpose, the study group included patients (N = 20; 13 male, 7 female) with complaints of unilateral sciatica, with foraminal stenosis caused by one level of LDH (L4-L5 or L5-S1). An gender-and age-matched control group (N = 27; 16 male, 11 female) was included. All the patients were examined on both the axial and longitudinal planes bilaterally at the same level using a convex array probe (1- 6 MHz, Supersonic Imagine, Aix en Provence, France).

Results

The sciatic nerve stiffness measured on longitudinal planes of the affected side was significantly higher than unaffected side (p < 0.001) and the control group (P < 0.05). Furthermore, the symptom duration of unilateral LDH is positively correlated with the stiffness the sciatic nerve (r = 0.52, p = 0.019).

Conclusion

According to these findings, ultrasound imaging can be considered as a useful tool to detect changes in the sciatic nerve due to disc herniation. This technique will have a promising prospect for many patients with unilateral LDH in monitoring stiffness during rehabilitation and before or after surgery.

Neuromuscular morphometric characteristics in low back pain with unilateral radiculopathy caused by disc herniation: An ultrasound imaging evaluation

BACKGROUND

Little is known about the neuromuscular morphometric characteristics in patients with sciatica.

OBJECTIVE

To evaluate the possible changes of nerve and muscle structures in patients with low back pain with unilateral radiculopathy due to lumbar disc herniation by ultrasound imaging.

DESIGN

A case-control observational study.

METHODS

Forty individuals were divided into case (n = 20; low back pain with unilateral radiculopathy due to disc herniation), and healthy control groups (n = 20). The thickness of lumbar multifidus at L5 level, and of lower limb muscles (i.e., biceps femoris, medial gastrocnemius, and soleus) was measured during both rest and full contraction to calculate the rest/contraction ratio of these muscles. Additionally, the sciatic nerve cross-sectional area and the echogenicity of the nerve and muscles were measured based on ultrasound imaging. The association between severity of low back pain radiculopathy (i.e., pain and patients' perceived disability) and rest/contraction ratio was assessed.

RESULTS

Patients with sciatica showed sciatic nerve enlargement, and different contraction ratios for multifidus (at L5)/ankle plantar flexors compared to the controls. The rest/contraction ratio for biceps femoris was similar between the two groups.

CONCLUSION

According to these findings, ultrasound imaging can be considered a useful tool to detect changes in the sciatic nerve and muscles due to disc herniation. Furthermore, regarding the observation of significant changes in muscle rest/contraction ratio in the multifidus and gastrosoleus, one might attribute these changes to the nerve root compression.

Sonoelastographic evaluation of the sciatic nerve in patients with unilateral lumbar disc herniation

OBJECTIVE

The aim of this study was to compare strain elastography (SE) and shear wave elastography (SWE) findings of the sciatic nerve in patients with unilateral lumbar disc herniation (LDH) and healthy control subjects.

MATERIALS AND METHODS

The study group included patients with complaints of unilateral sciatica for 3-12 months, with foraminal stenosis due to one level of LDH (L4-L5 or L5-S1). An age- and gender-matched control group was formed of healthy subjects. Evaluations were performed on both the axial and longitudinal planes from the bilateral gluteal region using a 5-9 MHz multifrequency convex probe.

RESULTS

There were 40 patients (20 male, 20 female) with a mean age of 43.1 ± 12.7 years in the study group, and 40 healthy subjects (22 male, 18 female) with a mean age of 42.9 ± 10.7 years in the control group (p > 0.05). The sciatic nerve stiffness assessed on both the axial (12.3 ± 3.7 kPA) and longitudinal (14.3 ± 3.8 kPA) planes of the involved side was significantly higher than non-involved side (axial: 6.8 ± 2.1 and longitudinal: 8.3 ± 2.3 kPA) in the patient group (p < 0.001).

CONCLUSIONS

Patients with unilateral LDH have increased stiffness of the sciatic nerve compared to healthy control subjects. Although the findings in this preliminary study show that shear wave elastography can detect a change in sciatic nerve stiffness in patients with unilateral LDH, larger studies are required to determine the clinical utility of this technique.

Noninvasive Measurement of Sciatic Nerve Stiffness in Patients With Chronic Low Back Related Leg Pain Using Shear Wave Elastography

OBJECTIVES

The purpose of this study was to determine whether sciatic nerve stiffness is altered in people with chronic low back-related leg pain by using shear wave elastography.

METHODS

In this cross-sectional study, the sciatic nerve shear wave velocity (ie, an index of stiffness) was measured in both legs of 16 participants (8 with unilateral low back-related leg pain and 8 healthy controls). Sciatic stiffness was measured during a passive ankle dorsiflexion motion performed at 2°/s in an isokinetic dynamometer. The ankle range of motion and passive torque, as well as muscle activity, were also measured.

RESULTS

In people with low back-related leg pain, the affected limb showed higher sciatic nerve stiffness compared to the unaffected limb (+11.3%; P = .05). However, no differences were observed between the unaffected limb of people with low back-related leg pain and the healthy controls (P = .34).

CONCLUSIONS

People with chronic low back-related leg pain have interlimb differences in sciatic nerve stiffness, as measured by a safe and noninvasive method: shear wave elastography. The changes found may be related to alterations in nerve mechanical properties, which should be confirmed by future investigations.

Ultrasonographic Evaluation of the Radial Nerves in Patients with Unilateral Refractory Lateral Epicondylitis

Objective

To evaluate the possible radial nerve entrapment of patients with unilateral refractory lateral epicondylitis (LE) by using ultrasound (US) and electroneuromyography.

Design

Cross-sectional study.

Setting

Three physical medicine and rehabilitation departments.

Subjects

Consecutive 44 patients (15 M, 29 F) with unilateral refractory LE.

Methods

All patients underwent detailed clinical, electrophysiological and ultrasonographic evaluations. Ultrasound imaging was used to evaluate thickness and presence of abnormal findings of the common extensor tendon (CET) and cross-sectional area (CSA) of the radial nerve (at spiral groove and before bifurcation) bilaterally. Unaffected sides of the patients were taken as controls.

Results

When compared with the unaffected sides, CET thickness and radial nerve CSAs (at both levels) were higher, and abnormal US findings regarding LE (47.7% vs. 6.8%) were more common on the affected sides than nonaffected sides (all P  < 0.001). Grip strength values were lower on the affected sides ( P  < 0.001). Electrophysiological studies were all normal, and similar between the two sides (all P  > 0.05). When subgroup analyses were performed after taking into account the hand dominance, affected and dominant sides were found to be the same in 31 and different in 13 patients. In subgroups, CETs and radial nerve CSAs at both levels were higher on the affected sides (all P  < 0.01).

Conclusions

Radial nerves and the CETs seem to be swollen on the affected sides, independent from the hand dominance of the patients with refractory LE. These results morphologically support the previous literature that attributes some of the chronic complaints of these patients actually to radial nerve entrapment.

Ultrasonographic evaluation of sciatic nerves in patients with spinal cord injury

STUDY DESIGN

Cross-sectional, controlled study.

OBJECTIVE

To evaluate the sciatic nerves of subjects with spinal cord injury (SCI) by using ultrasound (US) imaging and to explore whether US measurements are associated with clinical and electrophysiological findings.

SETTING

National Rehabilitation Center in Ankara, Turkey.

METHODS

Fifteen SCI subjects (12 male (M), 3 female (F)) and 23 (16 M, 7 F) healthy controls were included in the study. After clinical assessment of the subjects, lower limb nerve conduction studies and US imaging of the sciatic nerves were performed. Cross-sectional area (CSA) values of the sciatic nerves were correlated with the clinical and electrophysiologic data.

RESULTS

Mean CSA values were lower in the patient group when compared with the control group (P=0.042). Reduced compound motor action potentials regarding tibial and peroneal nerves were observed in the patient group (P=0.003 and P=0.005, respectively). US measurements did not correlate with the electrophysiological findings. However, sciatic nerve CSA values were positively correlated with body mass index in the control (r=0.534, P<0.05) and patient (r=0.482, P<0.05) groups.

CONCLUSION

Sciatic nerves seem to be smaller in subjects with SCI. Together with our electrophysiological data, this preliminary finding could possibly be attributed to primary axonal loss.