A 52-Year-Old Woman With Dysarthria, Ataxia, Xanthelasmas, and Miliary Pulmonary Nodules.

CASE PRESENTATION: A 52-year-old woman with no significant medical history was referred to our hospital for expedited workup of progressive dysarthria and ataxia over the past year. Prior CT angiography of the head and neck showed no relevant neurologic findings but did reveal miliary lesions in the lung apices, which was later confirmed via dedicated CT chest scan (Fig 1). Review of systems was negative for any respiratory, constitutional, or rheumatologic symptoms, except for new xanthelasma-like lesions over her forehead. She previously had smoked with 20 pack-years and had no TB risk factors. MRI of the face showed a 21-mm mass within the left external temporal fascia. MRI of the head showed diffuse leptomeningeal enhancement, right frontal lobe enhancement, and cerebellar and brainstem T2/fluid-attenuated inversion recovery hyperintensity, which prompted her admission to hospital.

Multifocal motor neuropathy.

PURPOSE OF REVIEW: Multifocal motor neuropathy (MMN) has specific clinical and electrophysiologic features but can be difficult to diagnose if cases are not typical. Intravenous immunoglobulin (IVIg) remains the core initial and long-term treatment. In this review, recent advances in the diagnosis, monitoring and treatment of MMN are discussed. RECENT FINDINGS: The pathology of MMN likely depends on immune-mediated attack of the nodes of Ranvier and paranodal regions leading to conduction block. Antiganglioside antibodies are present in over 50% of patients. The sensitivity of antibody detection can be improved by testing for GM1/galactocerebroside (GM1/GalC) complexes. Complement activation plays a key role in the pathophysiology of MMN. Subcutaneous immunoglobulins are an efficacious alternative to IVIg for maintenance therapy in MMN. Complement inhibitor eculizumab may be a potential future treatment, but further studies are necessary. SUMMARY: The European Federation of Neurological Societies (EFNS)/Peripheral Nerve Society (PNS) guidelines for the diagnosis of MMN are currently widely used but probably need revision. Nerve ultrasound and plexus/nerve MRI can be helpful in diagnostic dilemmas. Monitoring of disease and response to treatment may improve using disease-specific evaluation scales such as MMN-Rasch-built overall disability scale. Further research into the pathophysiology of MMN is necessary to direct future treatment strategies.

A repeatable ex vivo model of spondylolysis and spondylolisthesis.

STUDY DESIGN: An ex vivo biomechanical study using porcine spinal segments. OBJECTIVE: To produce a biomechanical model of both spondylolysis and spondylolisthesis using an accelerated cyclic loading model with intermittent impulse loads. SUMMARY OF BACKGROUND DATA: Only a few models of spondylolisthesis appropriate for biomechanical testing have been presented previously. Past modeling attempts have largely required nonphysiologic gross fracture of the pars before testing and have resulted in nonphysiologic endplate fracture. In these tests no clinically relevant spondylolisthesis was seen at the end of testing. A reproducible, clinically relevant model of both spondylolysis and spondylolisthesis would allow study of these disease processes, and facilitate the development and evaluation of advanced spinal implants optimized specifically for these pathologies. METHODS: Five porcine lumbar functional spinal units were tested (2 L4-L5, 3 L6-S1) after small notches had been created in the pars and after the disc had specific collagen fibers in the anterior anulus sectioned. Specimens were loaded with a constant cranial-caudal compressive force of 300 N and the application of cyclic anterior shear loads between 300 and 600 N with intermittent impulse loads to 1500 N until pars fracture occurred. Elevated cyclic loading then continued between 500 and 800 N. RESULTS: All specimens displayed bilateral pars fracture with the fractures passing through the points of notching and no damage to endplates or facet joints. Clinically-relevant Grade II spondylolisthesis was achieved in all 5 specimens. The mean slip at the conclusion of testing was 33%. CONCLUSION: Cyclic shear loading with intermittent impulse loads can reliably create fracture in the pars interarticularis in ex vivo porcine spine segments. Subsequent cyclic anterior motion of the superior vertebra results in clinically-relevant spondylolysis and spondylolisthesis.