Aims. The aims of this study were to determine the rates of surgical complications, reoperations, and readmissions following herniated lumbar disc surgery, and to investigate the impact of sociodemographic factors and comorbidity on the rate of such unfavourable events. Patients and Methods. This was a longitudinal observation study. Data from herniated lumbar disc operations were retrieved from a large medical database using a combination of procedure and diagnosis codes from all public hospitals in Norway from 1999 to 2013. The impact of age, gender, geographical affiliation, education, civil status, income, and comorbidity on unfavourable events were analyzed by logistic regression. Results. Of 34 639 operations, 2.7% (95% confidence interval (CI) 2.6 to 2.9) had a surgical complication, 2.1% (95% CI 2.0 to 2.3) had repeat surgery within 90 days, 2.4% (95% CI 2.2 to 2.5) had a non-surgical readmission within 90 days, and 6.7% (95% CI 6.4 to 6.9) experienced at least one of these unfavourable events. Unfavourable events were found to be associated with advanced age and comorbidity. Conclusion. The results suggest that surgical complications are less frequent than previously suggested. There are limited associations between sociodemographic patient characteristics and unfavourable events. Cite this article: Bone Joint J 2019;101-B:470–477

There is no universally agreed definition of cauda equina syndrome (CES). Clinical signs of CES including direct rectal examination (DRE) do not reliably correlate with cauda equina (CE) compression on MRI. Clinical assessment only becomes reliable if there are symptoms/signs of late, often irreversible, CES. The only reliable way of including or excluding CES is to perform MRI on all patients with suspected CES. If the diagnosis is being considered, MRI should ideally be performed locally in the District General Hospitals within one hour of the question being raised irrespective of the hour or the day. Patients with symptoms and signs of CES and MRI confirmed CE compression should be referred to the local spinal service for emergency surgery.

CES can be subdivided by the degree of neurological deficit (bilateral radiculopathy, incomplete CES or CES with retention of urine) and also by time to surgical treatment (12, 24, 48 or 72 hour). There is increasing understanding that damage to the cauda equina nerve roots occurs in a continuous and progressive fashion which implies that there are no safe time or deficit thresholds. Neurological deterioration can occur rapidly and is often associated with longterm poor outcomes. It is not possible to predict which patients with a large central disc prolapse compressing the CE nerve roots are going to deteriorate neurologically nor how rapidly. Consensus guidelines from the Society of British Neurological Surgeons and British Association of Spinal Surgeons recommend decompressive surgery as soon as practically possible which for many patients will be urgent/emergency surgery at any hour of the day or night.

Cite this article: Bone Joint J 2015;97-B:1390–4