Sacral Tarlov cysts: Neurophysiology abnormalities and correlation with pelvic sensory and visceral symptoms.

BACKGROUND AND PURPOSE: Recent studies suggest a possible association between Tarlov cysts (TCs), usually considered as incidental radiological findings, and neurological symptoms such as pain, numbness and urogenital complaints. The aim was to explore the relationship between TCs and sacral nerve root functions using pelvic neurophysiology tests, and to correlate changes with clinical symptoms and magnetic resonance imaging (MRI) findings. METHODS: Consecutive patients with sacral TCs, referred for pelvic neurophysiology testing and presenting with at least one symptom related to the pelvic area, participated in a cross-sectional review of symptoms using validated questionnaires. Findings of pelvic neurophysiology (pudendal sensory evoked potentials, sacral dermatomal sensory evoked potentials, external anal sphincter electromyography) and urodynamics testing were collected retrospectively. The relationship between neurophysiology, MRI findings and patients' symptoms was assessed using Fisher and ANOVA tests. RESULTS: Sixty-five females were included (mean age 51.2 ± 12.1 years). The commonest symptom was pain (92%). Urinary (91%), bowel (71%) and sexual (80%) symptoms were also frequently reported. Thirty-seven patients (57%) had abnormal neurophysiology findings reflecting sacral root dysfunction. No association was seen between MRI findings (size, location of the cysts, severity of compression) and neurophysiology. A negative association was observed between neurophysiology abnormalities and occurrence of urgency urinary incontinence (p = 0.03), detrusor overactivity (p < 0.01) and stress urinary incontinence (p = 0.04); however, there was no association with voiding difficulties. CONCLUSIONS: Contrary to current understanding, TCs are associated with injury to the sacral somatic innervation in the majority of patients with presumed symptomatic cysts. However, urinary incontinence is unlikely to be related to TC-induced nerve damage.

A clinico-neurophysiological study of urogenital dysfunction in MOG-antibody transverse myelitis.

OBJECTIVE: To assess the clinical, urodynamic, and neurophysiologic features of patients with persisting bladder, bowel, and sexual dysfunction after transverse myelitis in myelin oligodendrocyte glycoprotein antibody (MOG-Ab) disease. METHODS: Patients with a history of MOG-Ab disease-related transverse myelitis seen prospectively in a tertiary center uro-neurology service between 2017 and 2019 were included. They received cross-sectional clinical assessment; completed standardized questionnaires on bladder, bowel, and sexual symptoms; and underwent urodynamic and pelvic neurophysiologic investigations. RESULTS: Twelve patients (9 male) were included with a total of 17 episodes of transverse myelitis. Mean age at first attack was 26 (SD 9) years, and median follow-up duration was 50 (interquartile range 32-87) months. Acute urinary retention requiring bladder catheterization occurred in 14 episodes and was the first symptom in 10 episodes. Patients with lesions affecting the conus medullaris required catheterization for significantly longer durations than those without a conus lesion (median difference 15.5 days, p = 0.007). At follow-up, all patients had recovered full ambulatory function, but persisting bladder and bowel dysfunction moderately or severely affected quality of life in 55% and 36%, respectively, and 82% had sexual dysfunction. Pelvic neurophysiology demonstrated abnormal residual conus function in 6 patients. Urodynamic findings predominantly showed detrusor overactivity and/or detrusor-sphincter dyssynergia, indicative of a supraconal pattern of lower urinary tract dysfunction. CONCLUSIONS: Persisting urogenital and bowel dysfunction is common despite motor recovery. Although a proportion of patients had neurophysiologic evidence of residual conus abnormalities at follow-up, predominant urodyamic findings suggest that ongoing lower urinary tract dysfunction results from supraconal injury.

Phenytoin for neuroprotection in patients with acute optic neuritis: a randomised, placebo-controlled, phase 2 trial.

BACKGROUND: Acute demyelinating optic neuritis, a common feature of multiple sclerosis, can damage vision through neurodegeneration in the optic nerve and in its fibres in the retina. Inhibition of voltage-gated sodium channels is neuroprotective in preclinical models. In this study we aimed to establish whether sodium-channel inhibition with phenytoin is neuroprotective in patient with acute optic neuritis. METHODS: We did a randomised, placebo-controlled, double-blind phase 2 trial at two UK academic hospitals in London and Sheffield. Patients with acute optic neuritis aged 18-60 years, presenting within 2 weeks of onset, with visual acuity of 6/9 or worse, were randomly assigned (1:1) by minimisation via a web-based service to oral phenytoin (maintenance dose 4 mg/kg per day if randomised before or on July 16, 2013, and 6 mg/kg per day if randomised on or after July 17, 2013) or placebo for 3 months, stratified by time from onset, centre, previous multiple sclerosis diagnosis, use of disease-modifying treatment, and use of corticosteroids for acute optic neuritis. Participants and treating and assessing physicians were masked to group assignment. The primary outcome was retinal nerve fibre layer (RNFL) thickness in the affected eye at 6 months, adjusted for fellow-eye RNFL thickness at baseline, analysed in a modified intention-to-treat population of all randomised participants who were followed up at 6 months. Safety was analysed in the entire population, including those who were lost to follow-up. The trial is registered with ClinicalTrials.gov, number NCT 01451593. FINDINGS: We recruited 86 participants between Feb 3, 2012, and May 22, 2014 (42 assigned to phenytoin and 44 to placebo). 29 were assigned to phenytoin 4 mg/kg and 13 to phenytoin 6 mg/kg. Five participants were lost to follow-up, so the primary analysis included 81 participants (39 assigned to phenytoin and 42 to placebo). Mean 6-month RNFL thickness in the affected eye at 6 months was 81.46 µm (SD 16.27) in the phenytoin group (a mean decrease of 16.69 µm [SD 13.73] from baseline) versus 74.29 µm (15.14) in the placebo group (a mean decrease of 23.79 µm [13.97] since baseline; adjusted 6-month difference of 7.15 µm [95% CI 1.08-13.22]; p=0.021), corresponding to a 30% reduction in the extent of RNFL loss with phenytoin compared with placebo. Treatment was well tolerated, with five (12%) of 42 patients having a serious adverse event in the phenytoin group (only one, severe rash, was attributable to phenytoin) compared with two (5%) of 44 in the placebo group. INTERPRETATION: These findings support the concept of neuroprotection with phenytoin in patients with acute optic neuritis at concentrations at which it blocks voltage-gated sodium channels selectively. Further investigation in larger clinical trials in optic neuritis and in relapsing multiple sclerosis is warranted. FUNDING: US National Multiple Sclerosis Society, Multiple Sclerosis Society of Great Britain and Northern Ireland, Novartis, UK National Institute for Health Research (NIHR), and NIHR UCLH/UCL Biomedical Research Centre.