Luton cauda equina syndrome pathway: a pragmatic approach to achieve a national target of time to scan in UK district general hospitals

Abstract

Aims

Cauda equina syndrome (CES) is a rare neurosurgical emergency where diagnosis and treatment by emergency spinal decompression is time critical. A national CES pathway from Getting It Right First Time (GIRFT) suggested development of 24/7 MRI services at district general hospitals (DGHs). It gave a national target of time to scan time between MRI scan request and actual scan of less than four hours. The Luton CES pathway was introduced in 2021 at Luton and Dunstable University Hospital, UK, to improve the time (in hours) to a MRI service, as well as to streamline patient care for suspected CES. It aimed to improve time to scan and reduce need of out-of-hours transfer to tertiary centre for urgent MRI scan.

Methods

A retrospective review of patients who presented with suspected CES before (2018) and after (2024) the introduction of the pathway in Luton and Dunstable University Hospital. The time to scan was the primary outcome measure. Secondary outcome measures were number of patients scanned, scan positive rate (patients with actual CES who underwent emergency spinal decompression), patients meeting the national target of time to scan, and the number of patients needing out-of-hours transfer to tertiary centre for urgent MRI scan.

Results

The median time to scan improved from 8 hours 48 minutes to 34 minutes (p < 0.001). The number of patients scanned increased more than two-fold from 280 to 688. Patients meeting the national target increased from 66% to 90%. The number of patients also needing out-of-hours transfer reduced more than 50% from 17 to six.

Conclusion

A local dedicated pathway can achieve national targets, and reduce need for out-of-hours transfer to a tertiary centre for urgent MRI scan. This is achieved by efficient use of an existing in-hours MRI service, already available in every DGH of UK. This can be the pragmatic way forward for most DGHs until they establish a 24/7 MRI service.

Cite this article: Bone Jt Open 2026;7(2):235–240.

Introduction

Cauda equina syndrome (CES) is a neurosurgical emergency resulting from acute compression of lumbar and sacral nerve roots, resulting in a myriad of symptoms like bilateral sciatica, bowel/bladder or sexual dysfunction reduced perineal sensation, major muscle weakness in lower limbs. The nebulous nature of CES makes MRI essential in diagnosing this condition. The emphasis on getting MRI scan as soon as possible is because of two reasons: first, is that CES can progress from CES- I (incomplete; bladder dysfunction with some voluntary control) to CES-R (painless urinary retention) which would mean worse clinical outcomes. Second, the longer compression of cauda equina nerve roots, the worse is bladder outcome, even if the patient is CES-I at time of decompression.¹

Any delay in MRI would mean delay in emergency spinal decompression and a worse outcome. This is a concern in case of district general hospitals (DGHs), where the majority of patients present initially. DGHs typically do not have enough MRI scanning capacity to deliver timely MRI scan for CES. This is because MRI scanning is an underfunded resource in the UK. A report from the Clinical Imaging Board found that there are 6.1 MRI systems per million population which is one of the lowest among OECD countries.² Poor availability of out-of-hours provision of MRI scanning within the NHS is corollary to this. A survey of 234 trusts in England and Wales, with a 46% response rate, found that 24/7 access to MRI is 14% which is mostly concentrated in large teaching hospitals, and further 63% had extended a weekday service to 8.00 pm.³

The lack of resources mean suboptimal management with delays in getting an MRI scan. We aimed to improve this with existing resources which led to development of Luton CES pathway. The pathway was introduced to improve existing management of suspected CES in 2021 after multidisciplinary agreement between spinal surgeons, radiologists, and the MRI modality manager. It focused on better use of available in-hours MRI service (7.00 am to 6.00 pm) and streamlining the assessment and subsequent MRI scan for these patients. The aim was to reduce time to scan. Time to scan is time taken between an MRI scan request and actual MRI scan as defined by the Getting It Right First Time (GIRFT) pathway.⁴ It also intended to minimize the need of out-of-hours transfer to tertiary centre to get urgent MRI scan.

The Luton CES pathway is shown in Figure 1.

Fig. 1.

Cauda equina syndrome (CES) pathway.

In our hospital, patients with suspicion of CES with presence of a red flag finding based on SBNS/BASS standard⁵ are referred from emergency department (ED) or primary care to orthopaedics. We have orthopaedic on-call service with resident orthopaedic on-call registrar round the clock. All orthopaedic consultants including two consultant spinal surgeons participate in on-call rota. Under the pathway, on-call orthopaedic registrar saw all patients referred from either ED or primary care (i.e. general practitioner (GP) surgery and community MSK service). A thorough clinical history was taken. Relevant clinical examination including neurological examination, digital rectal examination and pre and post void bladder scan were performed and documented. Appropriate patients were referred for an urgent MRI scan. The clinical details of the request had to mention CES.

These requests need not be approved/vetted by radiology. The requests were accepted directly by an MRI radiographer and the next available slot for the MRI scan would be used. Every day, a predefined number of MRI scanning slots were reserved for the pathway. This would ensure that these patients were smoothly accommodated within inpatient MRI scanning list without the need of postponing any planned scans or overrunning list. This number was changed over time according to the need and eventually determined to be three slots/day for our hospital. MRI service provision in the hospital during this study included two MRI scanners providing 7.00 am to 6.00 pm scanning lists seven days a week. The protocol under the pathway was to perform dedicated lumbar spine MRI with screening T2 sagittal sequence of whole spine. All performed scans were added to urgent inpatient reporting list to ensure quick reporting. It was mandated for the radiologist to comment definitively on compression of cauda equina nerve roots in their report.

For patients presenting after the of the MRI department was closed, advice was sought from the neurosurgery department of the tertiary centre (Addenbrookes Hospital, Cambridge University Hospitals NHS Trust, UK). This was done via web-based portal ORION (orion.net). As per their advice, the patients were either admitted overnight and scanned on the first slot the next morning (7.00 am) or transferred out-of-hours to Addenbrookes Hospital for an urgent MRI scan. When the scan showed compression of cauda equina nerve roots, orthopaedic on-call team were informed and MRI images were transferred urgently via the image exchange portal to the tertiary centre. The team then liaised with the on-call neurosurgery service and organized for the transfer of patients to Addenbrookes Hospital by a blue-light ambulance for emergency spinal decompression.

Patients who did not have compression of cauda equina nerve roots were managed according to clinical circumstances either by inpatient admission or discharge. All such patients were discussed with on-call orthopaedic consultant in morning handover/trauma meeting and referred to hospital’s spinal consultants if appropriate. Patients with no significant findings were discharged back to primary care.

Methods

We did a retrospective review of patients who underwent urgent MRI scan under clinical suspicion of CES before and after the introduction of the pathway at Luton and Dunstable University Hospital. We have taken 2018 as base year to avoid skewing of results due to COVID-19 pandemic, and have compared this against 2024. We have included data from throughout the year to capture a bigger dataset and minimize bias. We have included all patients who underwent urgent inpatient MRI scan for clinical suspicion of CES. We have excluded urgent outpatient scanning requests from primary care, inpatient requests from the medical team with varied symptomatology other than specific CES.

Statistical analysis

The primary outcome measure was time to scan. This was obtained from the local radiology department. We also calculated proportion of these patients who had time to scan less than national target of four hours.⁴ We performed a one sample t-test to determine whether there was statistically significant difference between time to scan in 2018 and 2024.

Secondary outcome measures were the total number of patients undergoing MRI scan which was obtained from the local radiology department. The scan positive rate was studied which is the number of patients who had actual cauda equina compression and underwent emergency spinal decompression at Addenbrookes Hospital. This was obtained from from ORION portal. The number of patients who had to be transferred out-of-hours to Addenbrookes hospital for urgent MRI scan was studied. This was sourced from Addenbrookes Hospital’s radiology department. Statistical analysis was carried out using IBM SPSS v. 29 (IBM, USA).

Results

Table I shows a summary of the primary and secondary outcomes of the study.

Table I.

Comparison of cohorts before and after pathway.

Variable	2018 (before pathway)	2024 (after pathway)
Patients, n	280	688
Mean age, yrs (range)	58.7 (19 to 99)	50.9 (15 to 99)
Patients with actual CES, n	31	21
Scan positive rate, %	11	3
Median time to scan (min to max)	8 hr 48 mins (12 mins to 100 hrs)	34 mins (1 min to 23 hrs 59 mins)
Proportion of patients with time to scan < 4 hrs, %	66.42	89.68
Patients out-of-hours transfer, n	17	6

Demographics

The age group of the patients remained similar, with the average age in the fifties, as shown in Table I. The youngest patients were aged in their late teens and the eldest was aged 99 years.

Primary outcome: time to scan

The median time to scan was 8 hours and 48 minutes (IQR 12 minutes to 100 hours) in 2018. This substantially improved with implementation of the pathway. In 2024, the median time to scan was 34 minutes (IQR 1 minute to 23 hours 59 minutes).

This median time to scan under the pathway is well below the national target of four hours outlined in GIRFT national pathway.⁴ The Figure 2 and Figure 3 shows patient distribution according to time to scan. The normal distribution curve has shift to left in 2024 which represents quicker scanning time for larger proportion of patients.

Fig. 2.

Time to scan (2018).

Fig. 3.

Time to scan (2024).

Datasets from both years are large, and their measures of central tendency are shown in Table II. It shows that data from 2024 has a lower mean and standard error. This would mean the data is lower variability reflecting streamlined scanning under the pathway. We performed one sample t-test, as we could not do paired t-test because of different sample size (n). The results are as Table III. It showed a highly statistically significant difference between the year 2018 and 2024 with a p-value < 0.001. The improvement was also seen in the proportion of patients who achieved the national target of time to scan (66% in 2018 to almost 90% (89.68%) in 2024).

Table II.

Measures of central tendency for time to scan.

Year	No	Mean	Standard error of mean
2018	280	6 hrs 55 mins	55 mins
2024	688	2 hrs 11 mins	16 mins

Table III.

One sample t-test.

Year	t-value	Degrees of freedom	95% CI	p-value
2018	7.562	279	5 hr 2 mins to 8 hrs 38 mins	< 0.001
2024	8.285	687	1 hr 40 mins to 2 hrs 42 mins	< 0.001

Secondary outcomes

The number of patients who were scanned increased more than two-fold from 280 in 2018 to 688 in 2024. This is similar to findings from Salisbury District Hospital, UK, after implementation of their dedicated CES pathway (SPACES).⁶ The scan positive rate was 11% in 2018, which reduced to 3% in 2024. Similar rates have been reported in large datasets previously.⁷ Lastly, the number of patients who required an out-of-hours transfer to tertiary centre for urgent MRI scan reduced by more than 50% from 17 to six.

Discussion

CES remains an important public health problem due to its devastating long term effects on patients, their productivity and henceforth the society. In 2019, the British Society of Neurological Surgeons (SBNS) and the British Association of Spine Surgeons (BASS) had jointly developed standards of care for investigation and management of CES.⁵ It recommended a low threshold for MRI scan because of low reliability of clinical diagnosis. It emphasized on 24/7 availability of MRI scanning at referring hospital, and the need to do MRI scan for definitive diagnosis prior to discussion with spinal services.⁵ A nationwide retrospective audit of centres providing emergency spinal surgery (spinal units) was done in 2019 to check service delivery against this standard.⁸ The study included 4,441 referrals to spinal units for CES in a six-month period. This audit found substantial deviation in practice compared to SBNS/BASS standard. 63% of referrals, which were made to spinal units, did not have MRI scan.⁸ There was substantial variation in acquiring urgent MRI scan for suspected CES depending on whether the patient is in a spinal unit (four hours) versus referral to hospital, typically a DGH (13.2 hours). This has a knock on effect on subsequent spinal decompression surgery and eventual clinical outcome. Patients who undergo lumbar decompression for CES on day zero or one of admission tend to have better outcomes including mortality rate.⁹

A GIRFT review of spinal services in the UK recommended trusts to work on arranging out-of-hours MRI service immediately.¹⁰ They advised the NHS trust to work with GIRFT hubs to develop interim solutions if resources are not available, but work with NHS partners to ensure that the long term plan makes necessary provisions.¹⁰ A national suspected cauda equina pathway published in 2023 again makes the similar point and outlines a detailed stepwise plan to develop 24/7 MRI scanning service.⁴ Despite years of efforts, we have not seen much progress.

We believe there can be the following plausible reasons behind this persistent problem: lack of resources to commission on-call MRI radiographers; and limited capacity to accommodate these patients in routine MRI scanning lists as they are busy. A cost neutral solution has been suggested based on experience from Stoke Mandeville Hospital, UK.³ They suggested training all band six radiographers who take part in on-call CT rota with basic MRI of the brain and spine. These radiographers can then cross cover to the MRI service while doing on-call CT service. Apart from being complex to implement, there is a concern regarding whether on-call CT radiographers have enough time to do it, considering out-of-hours CT has become busier regarding time. When the scan fails to happen in the presenting hospital, the patient needs an out-of-hours transfer to spinal units for an urgent MRI scan. These transfers involve costs related to ambulance transfers, out-of-hours MRI scanning, and nursing and medical staffing at a tertiary centre; it has been estimated to be £6,000 per patient by Cambridge University Hospitals.¹⁰ Apart from the financial costs, these transfers also increase pressure on bed capacity in tertiary centres. However, it is important to note that most of financial costs are borne by spinal units and ambulance service, and not by the referring hospitals (i.e. DGHs). Henceforth, the financial incentive for the DGHs might not be substantial.

All recommendations thus far have taken a top down approach. They have come from spinal units, which are typically tertiary centres. They have persistently recommended improving availability of MRI scanning out-of-hours at hospitals where patients present in the first instance. Failure to achieve any meaningful progress may suggest that it is time to change tact and take a bottom up approach.

Our pathway has been designed at a DGH to work in a DGH. It was designed considering the challenges faced in a typical DGH. Lack of resources is a major impediment for expanding MRI service out of hours, and that has been the case despite aforementioned guidelines. However, we cannot blame this for the entirety of the problem. At times, there is lack of urgency in assessing these patients even if they present to the hospital in hours. Even after patients are seen and advised for urgent MRI scan, two more hurdles need to be crossed in organizing one. The first is to get it approved by an on-call radiologist, which is another discussion about the need for an urgent scan. The second is getting a slot once the request is approved as planned MRI lists are usually busy without any leeway and require a cancellation of another appointment. This would mean that a proportion of patients, despite having arrived in hours (typically evening time), would not be scanned at the presenting hospital. This is corroborated by findings of the ENTICE study,⁸ which found that despite more than 50% of referred patients arriving at the hospital during core hours (Monday to Friday from 9.00 am to 5.00 pm), the majority of referrals were made out of hours.

Our pathway addresses these challenges and focuses on the optimal use of in-hours MRI service at our hospital by minimizing delays at each step of getting an urgent MRI scan for suspected CES. It provides an unambiguous framework for assessing these patients and deciding on the need for urgent MRI scan for ED, as well as orthopaedic doctors. This minimizes variation in clinical judgement among doctors and deviation from the BASS/SBNS standard in deciding for or against urgent MRI scan. Time to scan improves because of bypassing the scan vetting process and availability of reserved slots on MRI scanning lists. It has been our experience that once the scan is requested, patients generally get the scan as soon as the scanning of the patient who was already in the MRI scanner is finished.

The pathway is a good example of “priming nudge” from the nudge principle for ED and orthopaedic doctors,¹¹ which reminds about CES, its time-critical nature, and, at the same time, improves the ease of getting an urgent MRI scan. It has been our experience that once widely known, the nudge effect extends to primary care setting as well. As a result, there is better awareness, which leads to to the point referrals to the hospital for clinical CES suspicion from primary care; be it GP surgery or musculoskeletal service. The utility of nudge principle has been proven in the healthcare setting.¹²

There has been growing interest recently in implementing dedicated pathways for scanning across the UK.^6,13 This is in line with growing emphasis, which is being put on to achieve time to scan < 4 hours. Our pathway has delivered remarkable results in a DGH with in-hours MRI service with median time to scan of 34 minutes and close to 90% of patients getting scan within four hours. A study from Oxford University Hospitals, UK, has demonstrated time to scan less than four hours in > 90% of patients as well.⁷ However, it is important to note that it is a tertiary centre with access to 24/7 MRI scanning. It can be argued that increasing the number of scans will put further pressure on already busy MRI services in DGHs and drive up related costs. However, we believe this would easily be offset many times over by reduction in medicolegal expenses to the trusts related to missed CES, the cost of overnight admission of a patient who was not scanned. Beyond that, there is cost saving for ambulance service and tertiary centres as out-of-hours transfer for urgent MRI scan are minimized. Moreover, increase in demand for MRI scans for suspected CES is multifactorial and can’t be attributed only to improved access to MRI service. Better clinician awareness and a high index of suspicion, as well as medicolegal aspects, play their role.

Limitation

A limitation is retrospective nature of this study. It has been performed in a single centre. It may not directly apply to every DGH because of different workings of each hospital (i.e. different distribution of responsibilities among the ED, acute medicine and orthopaedic departments) in managing these patients. The pathway might need modification according to available MRI service provision in individual hospital.

In conclusion, a locally designed pathway focusing on optimizing use of local MRI scanning facilities can substantially reduce time to scan and achieve national target of time to scan. This can be achieved using existing in-hours MRI service, which is already available in all UK DGHs. This also reduces the need for out-of-hours transfer to tertiary centres for urgent MRI scan saving valuable resources like ambulance transfer and beds in specialist hospitals. This may be a pragmatic step for most DGHs while they pursue the eventual aim of developing 24/7 MRI service as per national pathway.

Take home message

- A local dedicated pathway can achieve national targets and reduce the need for out-of-hours transfer to a tertiary centre for an urgent MRI scan.

- This is achieved by efficient use of an existing in-hours MRI service, already available in every district general hospital (DGH) of the UK. This can be the pragmatic way forward for most DGHs until they establish a 24/7 MRI service.

Data Availability

The datasets generated and analyzed in the current study are not publicly available due to data protection regulations. Access to data is limited to the researchers who have obtained permission for data processing. Further inquiries can be made to the corresponding author.