More questions than answers to the diagnosis and management of cauda equina syndrome-Authors' reply

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Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery, using clinician and participant reporting: a multi-centre prospective cohort study

Background: Cauda equina syndrome (CES) results from nerve root compression in the lumbosacral spine, usually due to a prolapsed intervertebral disc. Evidence for management of CES is limited by its infrequent occurrence and lack of standardised clinical definitions and outcome measures. Methods: This is a prospective multi-centre observational cohort study of adults with CES in the UK. We assessed presentation, investigation, management, and all Core Outcome Set domains up to one year post-operatively using clinician and participant reporting. Univariable and multivariable associations with the Oswestry Disability Index (ODI) and urinary outcomes were investigated. Findings: In 621 participants with CES, catheterisation for urinary retention was required pre-operatively in 31% (191/615). At discharge, only 13% (78/616) required a catheter. Median time to surgery from symptom onset was 3 days (IQR:1–8) with 32% (175/545) undergoing surgery within 48 h. Earlier surgery was associated with catheterisation (OR:2.2, 95%CI:1.5–3.3) but not with admission ODI or radiological compression. In multivariable analyses catheter requirement at discharge was associated with pre-operative catheterisation (OR:10.6, 95%CI:5.8–20.4) and one-year ODI was associated with presentation ODI (r = 0.3, 95%CI:0.2–0.4), but neither outcome was associated with time to surgery or radiological compression. Additional healthcare services were required by 65% (320/490) during one year follow up. Interpretation: Post-operative functional improvement occurred even in those presenting with urinary retention. There was no association between outcomes and time to surgery in this observational study. Significant healthcare needs remained post-operatively. Funding: DCN Endowment Fund funded study administration. Castor EDC provided database use. No other study funding was received

The accuracy of assessment of walking distance in the elective spinal outpatients setting

Self reported walking distance is a clinically relevant measure of function. The aim of this study was to define patient accuracy and understand factors that might influence perceived walking distance in an elective spinal outpatients setting. A prospective cohort study. 103 patients were asked to perform one test of distance estimation and 2 tests of functional distance perception using pre-measured landmarks. Standard spine specific outcomes included the patient reported claudication distance, Oswestry disability index (ODI), Low Back Outcome Score (LBOS), visual analogue score (VAS) for leg and back, and other measures. There are over-estimators and under-estimators. Overall, the accuracy to within 9.14 metres (m) (10 yards) was poor at only 5% for distance estimation and 40% for the two tests of functional distance perception. Distance: Actual distance 111 m; mean response 245 m (95% CI 176.3–314.7), Functional test 1 actual distance 29.2 m; mean response 71.7 m (95% CI 53.6–88.9) Functional test 2 actual distance 19.6 m; mean response 47.4 m (95% CI 35.02–59.95). Surprisingly patients over 60 years of age (n = 43) are twice as accurate with each test performed compared to those under 60 (n = 60) (average 70% overestimation compared to 140%; p = 0.06). Patients in social class I (n = 18) were more accurate than those in classes II–V (n = 85): There was a positive correlation between poor accuracy and increasing MZD (Pearson’s correlation coefficient 0.250; p = 0.012). ODI, LBOS and other parameters measured showed no correlation. Subjective distance perception and estimation is poor in this population. Patients over 60 and those with a professional background are more accurate but still poor

Randomised placebo-controlled trial on the effectiveness of nasal salmon calcitonin in the treatment of lumbar spinal stenosis

This is a double blind randomised controlled trial to assess the effectiveness of nasal salmon calcitonin in the treatment of lumbar spinal stenosis. The trial compared the outcome of salmon calcitonin nasal spray to placebo nasal spray in patients with MRI confirmed lumbar spinal stenosis. Lumbar spinal stenosis is one of the commonest conditions encountered by spine surgeons. It more frequently affects elderly patients and lumbar decompression has been used to treat the condition with variable success. Non operative measures have been investigated, but their success ranges from 15% to 43% in patients followed up for 1–5 years (Simotas in Clin Orthop 1(384):153–161, 2001). Salmon calcitonin injections have been investigated in previous trials and may have a treatment effect. Nasal salmon calcitonin has become available and if effective would have advantages over injections. Forty patients with symptoms of neurogenic claudication and MRI proven lumbar spinal stenosis were randomly assigned either nasal salmon calcitonin or placebo nasal spray to use for 4 weeks. This was followed by a ‘washout’ period of 6 weeks, and subsequent treatment with 6 weeks of nasal salmon calcitonin. Standard spine outcome measures including Oswestry disability index (ODI), low back outcome score, visual analogue score and shuttle walking test were administered at baseline, 4, 10 and 16 weeks. Twenty patients received nasal salmon calcitonin and twenty patients received placebo nasal spray. At 4 weeks post treatment there was no statistically significant difference in the outcome measures between the two groups. The change in ODI was a mean 1.3 points for the calcitonin group and 0.6 points for the placebo group (P = 0.51), the mean change in visual analogue score for leg pain was 10 mm in the calcitonin group and 0 mm in the placebo group (P = 0.51). There was no significant difference in walking distance between the two groups, with a mean improvement in walking distance of 21 m in the calcitonin group and 8 m in the placebo group (P = 0.78). At the end of the trial the ODI had improved by a mean of 3.7 points in the calcitonin group and 3.8 points in the placebo group (P = 0.44). This randomised placebo controlled trial has not shown any treatment effect in patients with lumbar spinal stenosis treated with nasal salmon calcitonin

Cauda equina syndrome: poor inter-rater agreement for diagnostic categories

Aims: Patients with cauda equina syndrome (CES) require emergency imaging and surgical decompression. The severity and type of symptoms may influence the timing of imaging and surgery, and help predict the patient’s prognosis. Categories of CES attempt to group patients for management and prognostication purposes. We aimed in this study to assess the inter-rater reliability of dividing patients with CES into categories to assess whether they can be reliably applied in clinical practice and in research. Methods: A literature review was undertaken to identify published descriptions of categories of CES. A total of 100 real anonymized clinical vignettes of patients diagnosed with CES from the Understanding Cauda Equina Syndrome (UCES) study were reviewed by consultant spinal surgeons, neurosurgical registrars, and medical students. All were provided with published category definitions and asked to decide whether each patient had ‘suspected CES’; ‘early CES’; ‘incomplete CES’; or ‘CES with urinary retention’. Inter-rater agreement was assessed for all categories, for all raters, and for each group of raters using Fleiss’s kappa. Results: Each of the 100 participants were rated by four medical students, five neurosurgical registrars, and four consultant spinal surgeons. No groups achieved reasonable inter-rater agreement for any of the categories. CES with retention versus all other categories had the highest inter-rater agreement (kappa 0.34 (95% confidence interval 0.27 to 0.31); minimal agreement). There was no improvement in inter-rater agreement with clinical experience. Across all categories, registrars agreed with each other most often (kappa 0.41), followed by medical students (kappa 0.39). Consultant spinal surgeons had the lowest inter-rater agreement (kappa 0.17). Conclusion: Inter-rater agreement for categorizing CES is low among clinicians who regularly manage these patients. CES categories should be used with caution in clinical practice and research studies, as groups may be heterogenous and not comparable