Evaluation of the role of anal tone and perianal sensation examination in the assessment of suspected cauda equina syndrome.

PURPOSE: Cauda equina syndrome (CES) can present with a varied constellation of clinical signs and symptoms, which together with the time-sensitive nature of the condition and risk of catastrophic clinical outcome, presents a significant challenge to those assessing patients with this suspected diagnosis. Anal tone is commonly tested during initial assessment using a digital rectal examination (DRE). This study aims to evaluate the diagnostic value of anal tone and perianal sensation assessment in patients with suspected CES and report modern prevalence data on CES within a neurosciences centre. MATERIALS AND METHODS: Consecutive patients with suspected CES presenting over three years to the Emergency Department (ED) of a busy tertiary centre were included in the study. History and examination findings, documented in the ED notes, were assessed and these variables were correlated with the presence or absence of cauda equina compression on subsequent magnetic resonance imaging (MRI). RESULTS: Out of 1005 patients with suspected CES, 117 (11.6%) had MRI confirmed cauda equina compression (MRI + ve CES). 35% of MRI + ve patients and 31% of MRI -ve patients had reduced anal tone. Using univariate and multivariable logistic regression analyses, no associations were found between abnormal anal tone and MRI + ve CES for patients of all ages. The univariate logistic regression analysis identified altered perianal sensation to be significantly associated with MRI + ve CES in patients ≤42 years old. This association was no longer present when an adjusted multivariable logistic regression was performed. CONCLUSION: The prevalence of MRI + ve CES was 11.6%. Our findings suggest that the clinical finding of reduced anal tone has no demonstrable diagnostic value for those with suspected CES, either in itself or in combination with other clinical findings. Further studies are needed to confirm the diagnostic efficacy of assessing perianal sensation in this context.

Determination of potential risk characteristics for cauda equina compression in emergency department patients presenting with atraumatic back pain: a 4-year retrospective cohort analysis within a tertiary referral neurosciences centre.

OBJECTIVE: Atraumatic back pain is an increasingly common presentation to the ED. A minority of these cases will have significant structural pathology, resulting in acute cauda equina compression (CEC). Although clinicians often look for 'red flags' to identify potential CEC, the prognostic accuracy of these presenting symptoms and clinical examination findings is unclear. We sought to evaluate the accuracy of individual clinical features in a large cohort of ED patients with atraumatic backpain and reference standard imaging, for the diagnosis of CEC. METHODS: A retrospective case note review from 2014 to 2018 within an established ED atraumatic back pain pathway, undertaken at the largest tertiary spinal referral centre in the UK. We analysed routine data, collected prospectively by treating clinicians within a structured electronic health record clinical proforma. Data on signs and symptoms in 996 patients with suspected CEC referred for definitive MRI over a 4-year study period were extracted and compared against a final reference standard diagnosis. RESULTS: We identified 111 patients with radiological evidence of CEC within the cohort referred for definitive imaging (111/996, 11.1%), of whom 109 (98.2%) underwent operative intervention. Patients with CEC were more likely to present with bilateral leg pain (OR=2.2), dermatomal sensory loss (OR 1.8) and bilateral absent ankle or ankle and knee jerks (OR=2.9). Subjective weakness was found to be associated with CEC on univariate but not multivariate analysis. We found no relationship between digital rectal examination findings and the diagnosis of CEC. CONCLUSIONS: In our cohort, factors independently associated with CEC diagnosis on MRI included bilateral leg pain, dermatomal sensory loss. Loss of lower limb reflexes was strongly suggestive of CES (likelihood ratio 3.4 on multivariate logistic regression). Our findings raise questions about the diagnostic utility of invasive digital rectal examination.

Clinical and neuroradiological characterisation of spinal lesions in adults with Neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) manifests itself in many ways in the spine. This study aims to report the types of spinal lesions, clinical and demographic data in a large cohort from a complex NF1 centre. The characteristics of those with spinal neurofibromatosis, where neurofibromas are present on every spinal nerve root, were sought for comparison with the wider group of NF1 patients. This is a retrospective review of MDT minutes of 303 patients from a UK NF1 centre and the largest reported series of NF1 patients based on radiological data. Prevalence of each symptom and lesion was calculated and statistically significant associations were established. The most reported findings were cutaneous lesions (44.9%) and neurological deficit (27.4%). 28.4% had dural ectasia, 52.5% had some form of spinal deformity. 57.8% had spinal nerve root tumours, the most common of which were at C2. The most progressive lesions were spinal nerve root tumours (29.1%). The only statistically significant association found was between dural ectasia and spinal deformity (P < 0.003), where dural ectasia is associated with a 32.6% increase in spinal deformity incidence. This is the largest descriptive study of spinal lesions in NF1. Spinal tumours and spinal deformity are prevalent in NF1. The predilection of spinal tumours for flexible spinal regions suggests that repetitive movement might be an important factor in pathogenesis. Physicians and patients should be alert to the observation that although many spinal neurofibromatosis patients display no neurological deficit, they often have significant lesions which require monitoring and sometimes surgery.