CAUDA EQUINA SYNDROME: Case report of a neurosurgical emergency
Biodun Ogungbo, Cedarcrest Hospitals, Garki II, Abuja, Nigeria
Thomas Russell, Western General Hospital, Edinburgh, United Kingdom
Corresponding author:
Dr Biodun Ogungbo MBBS, FRCS, FRCS, MSc, Consultant Neurosurgeon.
Email: ogungbo@btinternet.com
Phone: 00-234-7082350074
Abstract
We present a young woman with symptoms and signs of cauda equina syndrome. Early surgical intervention led to improvement and restoration of sphincter function. The case serves to refresh our minds about this clinical entity.
Case report
A 37-years old woman was admitted to the Western General Hospital, Edinburgh as an emergency following a referral from her general practitioner; with a 4 day history of sudden onset of severe low back pain. This pain had progressively worsened over the few days. On the morning of admission, she woke up with the pain radiating down both lower limbs associated with leg weakness. She also noticed perineal sensory loss and bladder dysfunction. She could not feel the stream of flow through her urethra.
On examination, she walked with an antalgic gait and had reduced range of movement of her lumbo-sacral spine with tenderness to touch. Straight leg raising (SLR) was 30° with positive Lasègue's sign and sciatic stretch test bilaterally. She had normal objective muscle power in all muscle groups in the lower limbs. The knee jerks were heightened and the ankle jerks were depressed. She had reduced sensation to touch and pin prick from S1 to S4 dermatomes in the perineum.
An urgent MRI of her lumbosacral spine revealed a large L5/S1 central disc prolapse compressing the cauda equine at that level (Figure 1)
Figure 1
Legend: Large L5/S1 central disc prolapse (arrows) on sagittal (left) and axial (right) MRI scan. There is significant encroachment of the disc into the spinal canal with compression of the sacral nerves
She was prepared for theatre and had an emergency L5/S1 decompression and discectomy. She was catherised preoperatively, but post surgery her bladder sensation and sphincter function gradually improved. She had normal sphincter function at the time of discharge 5 days later. The leg pain and weakness had also improved significantly.
Discussion
Cauda equina syndrome (CES) is a clinical entity due to compression of the lumbo-sacral nerves. CES symptoms may have sudden onset and evolve rapidly or sometimes chronically. Low back pain may be the most significant symptoms, accompanied by sciatica.(1) Patients present with radicular pain which could be unilateral or bilateral. This is associated with numbness and weakness in the areas supplied by the nerves being compressed in the spinal canal. In addition, patients complain of perineal numbness and varying degrees of bladder or bowel (sphincter) disturbances. This could be associated with loss of anal tone, impotence and sexual dysfunction.(1)
The syndrome could be complete or incomplete. Complete means full loss of bowel and bladder control with little chance of recovery. Incomplete CES means that there are evolving symptoms of bowel and bladder dysfunction without full loss of function. This is potentially reversible. This potential is why CES is a neurosurgical emergency. CES from lumbar herniated discs is considered the only absolute indication for surgery. It is considered a neurosurgical emergency with the outcome related to how quickly it is diagnosed and treated.(2) MRI is usually the preferred investigation approach.
There are many possible causes of CES. The commonest cause is lumbar disc prolapse but it can be caused by epidural hematomas, tumours, trauma and infection. A percentage of patients present with symptoms of CES but without any radiological evidence of structural pathology on MRI scan. While some may have an alternative organic cause, there is a "functional" origin in many patients.(3)
Our patient presented with a large L5/S1 disc prolapse causing significant narrowing of the spinal canal and compression of the nerves. This caused bilateral sciatic pain, weakness of the muscles in the ankle, loss of ankle reflex, perineal sensory loss and problems with bowel and bladder sphincter function.
Surgical intervention is often required to decompress the cauda equina by removing the compressing element. Most authors recommend a wide decompressive laminectomy when surgery is performed.(2) If performed emergently this could lead to complete restoration of function and full recovery. Patients who have had complete CES are difficult to return to a normal status.(1) In a young patient, this could be very devastating. The results of recovery of bladder function are felt by many authors to be related to early diagnosis and surgical intervention.
Conclusion
The incidence and prevalence of CES has not been evaluated in the Nigerian population. This is an area worthy of research. The constraint of lack of easy access to MRI scans and affordability calls for adaptability and creativity in the diagnosis of CES in Nigeria. Early referral to the care of a neurosurgeon is critical and could be beneficial to the patient.(4) Lumbar CT and CT myelography may be suitable radiological investigations as it is imperative that the diagnosis is made early and intervention offered in a timely fashion. This case report serves to remind us about this clinical entity.
References
1. Ma B, Wu H, Jia LS, Yuan W, Shi GD, Shi JG. Cauda equina syndrome: a review of clinical progress. Chin Med J (Engl) 2009; 122(10):1214-22.
2. Olivero WC, Wang H, Hanigan WC, et al. Cauda equina syndrome (CES) from lumbar disc herniations. J Spinal Disord Tech 2009; 22(3):202-6.
3. Rooney A, Statham PF, Stone J. Cauda equina syndrome with normal MR imaging. J Neurol 2009; 256(5):721-5.
4. Crowell MS, Gill NW. Medical screening and evacuation: cauda equina syndrome in a combat zone. J Orthop Sports Phys Ther 2009;39(7):541-9.
