Aims. Diagnosis of cauda equina syndrome (CES) remains difficult; clinical assessment has low accuracy in reliably predicting MRI compression of the cauda equina (CE). This prospective study tests the usefulness of ultrasound bladder scans as an adjunct for diagnosing CES. Methods. A total of 260 patients with suspected CES were referred to a tertiary spinal unit over a 16-month period. All were assessed by Board-eligible spinal surgeons and had transabdominal ultrasound bladder scans for pre- and post-voiding residual (PVR) volume measurements before lumbosacral MRI. Results. The study confirms the low predictive value of ‘red flag’ symptoms and signs. Of note ‘bilateral sciatica’ had a sensitivity of 32.4%, and a positive predictive value (PPV) of only 17.2%, and negative predictive value (NPV) 88.3%. Use of a PVR volume of ≥ 200 ml was a demonstrably more accurate test for predicting cauda equina compression on subsequent MRI (p < 0.001). The PVR sensitivity was 94.1%, specificity 66.8%, PPV 29.9% and NPV 98.7%. The PVR allowed risk-stratification with 13% patients deemed ‘low-risk’ of CES. They had non-urgent MRI scans. None of the latter scans showed any cauda equina compression (p < 0.006) or individuals developed subsequent CES in the intervening period. There were considerable cost-savings associated with the above strategy. Conclusion. This is the largest reported prospective evaluation of suspected CES. Use of the PVR volume ≥ 200 ml was considerably more accurate in predicting CES. It is a useful adjunct to conventional clinical assessment and allows risk-stratification in managing suspected CES. If adopted widely it is less likely incomplete CES would be missed. Cite this article: Bone Joint J 2020;102-B(6):677–682

Aims

The early diagnosis of cauda equina syndrome (CES) is crucial for a favourable outcome. Several studies have reported the use of an ultrasound scan of the bladder as an adjunct to assess the minimum post-void residual volume of urine (mPVR). However, variable mPVR values have been proposed as a threshold without consensus on a value for predicting CES among patients with relevant symptoms and signs. The aim of this study was to perform a meta-analysis and systematic review of the published evidence to identify a threshold mPVR value which would provide the highest diagnostic accuracy in patients in whom the diagnosis of CES is suspected.

The diagnostic sub-categorization of cauda equina syndrome (CES) is used to aid communication between doctors and other healthcare professionals. It is also used to determine the need for, and urgency of, MRI and surgery in these patients. A recent paper by Hoeritzauer et al (2023) in this journal examined the interobserver reliability of the widely accepted subcategories in 100 patients with cauda equina syndrome. They found that there is no useful interobserver agreement for the subcategories, even for experienced spinal surgeons. This observation is supported by the largest prospective study of the treatment of cauda equina syndrome in the UK by Woodfield et al (2023). If the accepted subcategories are unreliable, they cannot be used in the way that they are currently, and they should be revised or abandoned. This paper presents a reassessment of the diagnostic and prognostic subcategories of cauda equina syndrome in the light of this evidence, with a suggested cure based on a more inclusive synthesis of symptoms, signs, bladder ultrasound scan results, and pre-intervention urinary catheterization. Cite this article: Bone Joint J 2024;106-B(3):227–231

Introduction. Urinary catheterisation can cause bacteraemia and therefore may be associated with a risk of infection in hip and knee arthroplasty. However postoperative urinary retention can be distressing for the patient. This study investigates the factors that might predict the need for postoperative catheterisation in order to help develop a protocol to decide who should be electively catheterised. Methods. A prospective blinded study of 128 consecutive patients undergoing lower limb arthroplasty was carried out. No patient underwent perioperative catheterisation. Data obtained included sex, age, joint (hip or knee replacement), prostate score (IPSS), previous urinary retention, comorbidities and residual bladder volume after attempted complete voiding measured using an ultrasound bladder scanner. The type of anaesthesia and the requirement for urinary catheterisation postoperatively were recorded. Predictive risk factors were identified using binary logistic regression, and expressed as odds ratios (OR) and 95% confidence intervals (CI). Results. The mean age was 69.5 years (SD 8.9). There were 56 males and 72 females. 38 patients (30%) required postoperative catheterisation. Logistic regression identified the following predictive risk factors: bladder scan volume per ml increase (OR 1.006; CI 1.000–1.012); male sex (OR 5.51; CI 2.01–15.16); previous catheter (OR 4.26; CI 1.53–11.82); spinal/epidural/combined spinal epidural (CSE) anaesthesia (OR 6.78; CI 1.75–26.32); moderate IPSS score (OR 5.15; CI 1.73–15.37); severe IPSS score (OR 3.53; CI 0.605–20.54). The specificity of our model is 91%, the positive predictor value 71% and negative predictor value 82%. Discussion. Post-voiding bladder scan volume (1ml increase = 0.6% increased risk), male sex, history of retention, medium or high IPSS score and an epidural, spinal or CSE anaesthetic are independent risk factors that can be used preoperatively to predict the likelihood of postoperative retention

Urinary catheterisation may be associated with a risk of infection in hip and knee arthroplasty, however post-operative urinary retention can be distressing for the patient. This study investigates the factors that might predict the need for post-operative catheterisation. A prospective blinded study of 128 consecutive patients undergoing lower limb arthroplasty was carried out. Data obtained included sex, age, joint (hip or knee), prostate score (IPSS), previous urinary retention, co-morbidities and residual bladder volume after attempted complete voiding measured using an ultrasound bladder scanner. Anaesthetic type and requirement for urinary catheterisation postoperatively were recorded. Predictive risk factors were identified using binary logistic regression, and expressed as odds ratios (OR) and 95% confidence intervals (CI). The mean age was 69.5 years. There were 56 males and 72 females. 38 patients (30%) required post-operative catheterisation. Logistic regression identified the following predictive risk factors: bladder scan volume per ml increase (OR 1.006; CI 1.000–1.012); male sex (OR 5.51; CI 2.01–15.16); previous catheter (OR 4.26; CI 1.53–11.82); spinal/epidural/combined spinal epidural anaesthesia (OR 6.78; CI 1.75–26.32); moderate IPSS score (OR 5.15; CI 1.73–15.37); severe IPSS score (OR 3.53; CI 0.605–20.54). Our model specificity is 91%, positive predictor value 71% and negative predictor value 82%

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.