Research Review: Study aims to help clinicians improve CES diagnosis

Study title: Assessment of Cauda Equina Syndrome progression pattern to improve diagnosis

Cauda equina syndrome (CES) is a relatively rare, albeit serious condition that requires immediate surgical intervention. Bladder, bowel and sexual dysfunction are associated with fully developed CES and result in significant pain, dysfunction and economic burden to patients. Litigation is common following such cases, with average compensation for patients in the U.S. exceeding $500,000. Delayed diagnosis of CES is the most commonly cited reason for these large settlements, with poor prognosis associated with delay in diagnosis and initiation of appropriate treatment.

While CES typically presents as an exacerbation of acute low back pain and bi/unilateral sciatica followed by bladder and/or bowel dysfunction, the progression of CES symptoms can vary greatly depending on the primary disease, spinal segments involved, speed of onset and individual patient differences. As such, there is no consensus on whether patients with symptoms other than bladder/bowel dysfunction can appropriately be diagnosed with CES. The purpose of this study was to investigate the pattern of CES by examining individual patient data to analyze the progression of CES using sequential pattern mining, with a goal of helping clinicians with the timely diagnosis of CES.

A total of 264 cases were studied, including 227 from case reports and 37 from retrospective studies that supplied detailed patient medical histories (mean age: 44.75, 63.26 per cent male). Forty-two cases were deemed acute, such that all symptoms presented simultaneously. These patients were excluded, resulting in 222 cases being included in the final analysis.

CES was stratified into three stages: early CES (CESE), incomplete CES (CESI) and CES in retention (CESR). CESE generally involved bilateral peripheral nerve dysfunction (sensory-motor deficits, pain, paraesthesia). CESI occurred after CESE and characterized by reduced bladder and/or bowel function. CESR was considered the advanced stage, with complete loss of bladder and/or bowel control.

Twelve initial CES symptoms were identified and used in the progression analysis: bilateral lower extremity pain; bilateral lower extremity paraesthesia; motor power abnormality of bilateral lower extremity; bilateral sciatica; paraesthesia in perineal region; pain in perineal region; reduction in bladder function; reduction in bowel and anal function; reduction in sexual function; bladder dysfunction; bowel and anal dysfunction; and sexual dysfunction.

The most commonly observed initial symptoms in non-acute CES were: bilateral lower extremity pain (69 cases); bilateral lower extremity paraesthesia (54 cases); perineal paraesthesia (49 cases).

Among the 222 cases of CES that were diagnosed as either CESI or CESR, 179 had experienced CESE symptoms without being diagnosed.

Study methods
A systematic search of MEDLINE/PubMed was conducted up to May 2013, using the MeSH (medical subject heading) terms “polyradiculopathy” and “cauda equina syndrome” for articles published in English.

Each medical history was carefully reviewed and the occurrence order of the 12 CES symptoms recorded. Cases with simultaneous occurrence of symptoms were considered acute (without order or progression) and were therefore not included in the final analysis. The order of symptom occurrence was analyzed using sequential pattern mining – looking for repeating patterns that identify potential associations between different events.

Study limitations:

• Data included may be subject to information bias due to interclinician variations in approaches to obtaining CES medical history.
• Although almost all the available data from published literature was included, the authors were unable to rule out publication bias and selection bias.

Conclusions, applications
Clinicians currently tend to diagnose CES only after abnormalities in bladder and/or bowel function appear, often resulting in delayed diagnosis. Patients with symptoms of CESE are often not investigated further for CES, even though the current study found 99.4 per cent of these patients progress to CESI or CESR. Clinicians should consider CES as a differential diagnosis where symptoms consistent with CESE are present, to rule out potential cases of CESI/CESR.

Dr. SHAWN THISTLE owns and operates Research Review Service Inc., helping clinicians integrate scientific evidence into practice through subscription-based service (researchreviewservice.com), online courses (onlinecourses.researchreviewservice.com) and seminars (epicureanscholar.com).