Nerve conduction assessment and magnetic resonance imaging for the diagnosis of localized hypertrophic neuropathy of the sciatic nerve and the lumbo-sacral plexus.

Localized hypertrophic neuropathy (LHN) are slowly growing nerve lesions causing progressive nerve deficit and weakness. We present the case of a 32-year old woman with long history of motor and sensory deficit complains along the sciatic nerve territory. The muscles involved were featured by delay in F waves at nerve conduction assessment. Magnetic resonance imaging (MRI) showed specific patterns, low intense on T1 and abnormally hyper intense on short tau inversion recovery (STIR) and T2, with no obvious enhancement, features compatible with either LHN or intraneural perineurioma (IP) of the sciatic nerve and/or the lumbosacral plexus. Focal thickening and hypertrophy of the sciatic nerve with preserved fascicular configuration and progressive enlargement of the right lumbosacral plexus could be noted. A nerve conduction assessment followed by an MRI eventually allowed to diagnose LHN, without performing a nerve biopsy. Although similar, LHN and IP are two distinct lesions which should be diagnosed and differentiated as soon as possible, to avoid potential complications due to delayed diagnosis and/or misdiagnosis.

Update in the evaluation of peripheral nerves by MRI, from morphological to functional neurography. / Actualización en la valoración de los nervios periféricos mediante resonancia magnética: de la neurografía morfológica a la funcional.

Imaging studies of peripheral nerves have increased considerably in the last ten years. In addition to the classical and still valid study by ultrasound, new neurographic techniques developed from conventional morphological sequences (including 3D isotropic studies with fat suppression) are making it possible to assess different peripheral nerves and plexuses, including small sensory and/or motor branches, with great precision. Diffusion-weighted sequences and diffusion tensor imaging have opened a new horizon in neurographic studies. This new approach provides morphological and functional information about the internal structure and pathophysiology of the peripheral nerves and diseases that involve them. This update reviews the different MR neurography techniques available for the study of the peripheral nerves, with special emphasis on new sequences based on diffusion.

A radiologic and anatomic assessment of injectate spread following transmuscular quadratus lumborum block in cadavers.

We performed bilateral transmuscular quadratus lumborum blocks in six cadavers using iodinated contrast and methylene blue. Computed tomography imaging was performed in four cadavers and anatomical dissection was completed in five. This demonstrated spread to the lumbar paravertebral space in 63% of specimens, laterally to the transversus abdominis muscle in 50% and caudally to the anterior superior iliac spine in 63% of specimens. There was no radiographic evidence of spread to the thoracic paravertebral space. Anatomical dissection revealed dye staining of the upper branches of the lumbar plexus and the psoas major muscle in 70% of specimens. Further clinical studies are required to confirm if the quadratus lumborum block might be a suitable alternative to lumbar plexus block.

Successful Identification and Assessment of the Superior Cluneal Nerves with High-Resolution Sonography.

BACKGROUND: Low back pain is a disabling and common condition, whose etiology often remains unknown. A suggested, however rarely considered, cause is neuropathy of the medial branch of the superior cluneal nerves (mSCN)-either at the level of the originating roots or at the point where it crosses the iliac crest, where it is ensheathed by an osseo-ligamentous tunnel. Diagnosis and treatment have, to date, been restricted to clinical assessment and blind infiltration with local anesthetics. OBJECTIVE: To determine whether visualization and assessment of the mSCN with high-resolution ultrasound (HRUS) is feasible. STUDY DESIGN: Interventional cadaver study and case series. METHODS: Visualization of the mSCN was assessed in 7 anatomic specimens, and findings were confirmed by HRUS-guided ink marking of the nerve and consecutive dissection. Further, a patient chart and image review was performed of patients assessed at our department with the diagnosis of mSCN neuropathy. RESULTS: The mSCN could be visualized in 12 of 14 cases in anatomical specimens, as confirmed by dissection. Nine patients were diagnosed with mSCN syndrome of idiopathic or traumatic origin. Diagnosis was confirmed in all of them, with complete resolution of symptoms after HRUS-guided selective nerve block. LIMITATIONS: These findings are first results that need to be evaluated in a systematic, prospective and controlled manner. CONCLUSION: We hereby confirm that it is possible to visualize the mSCN in the majority of anatomical specimens. The patients described may indicate a higher incidence of mSCN syndrome than has been recognized. mSCN syndrome should be considered in patients with low back pain of unknown origin, and HRUS may be able to facilitate nerve detection and US-guided nerve block.