Cauda equina syndrome (CES) is a serious neurologic condition in which damage to the cauda equina causes acute loss of function of the lumbar plexus, (nerve roots) of the spinal canal below the termination (conus medullaris) of the spinal cord. CES is a lower motor neuron lesion.
The nerve roots extending from the lumbar spine are susceptible to compression, leading to CES. Intervertebral discs can be dislocated to different degrees, contributing to such compression. Various etiologies of CES include fractures, abscesses, hematomas, and any compression of the relevant nerve roots.
Injuries to the thoracolumbar spine will not necessarily result in a clinical diagnosis of CES, but in all such cases it is necessary to consider. Few epidemiological studies of CES have been done in the United States, owing to difficulties such as amassing sufficient cases as well as defining the affected population, therefore this is an area deserving of additional scrutiny.
Traumatic spinal cord injuries occur in approximately 40 people per million annually in the United States, resulting from traumas due to motor vehicle accidents, sporting injuries, falls, and other factors.
An estimated 10 to 25% of vertebral fractures will result in injury to the spinal cord.
Thorough physical examinations are required, as 5 to 15% of trauma patients have fractures that initially go undiagnosed.
Gender of CES patients admitted to the hospital. CES is slightly more common in men than women. The most frequent injuries of the thoracolumbar region are to the conus medullaris and the cauda equina, particularly between T12 and L2. Of these two syndromes, CES is the more common.
CES mainly affects middle-aged individuals, particularly those in their forties and fifties, and presents more often in men.
It is not a typical diagnosis, developing in only 4 to 7 out of every 10,000 to 100,000 patients, and is more likely to occur proximally.
Disc herniation is reportedly the most common cause of CES, and it is thought that 1 to 2% of all surgical disc herniation cases result in CES.
No set risk factors have been clearly defined for CES at this point in time.
Individuals most at risk for disc herniation are the most likely to develop CES. Race has little influence with the notable exception that African Americans appear slightly less likely to develop CES than other groups; similarly, men are slightly more likely to develop CES than women.
Middle age also appears to be a notable risk factor, as those populations are more likely to develop a herniated disc; heavy lifting can also be inferred as a risk factor for CES.
Examination for pain sensation, by pinprick, shows leg (lumbar nerves) analgesia with perineal (sacral nerves) escape. The maintenance of perineal sensation with absence of pain sensation over the lumbar nerve roots is typical for an extra-medullary and intra-thecal (outside the cord and within the dural sheath) process. Inability to walk, with this unusual sensory examination completes a triad of signs and usually represents spinal tuberculosis. The triad is paraplegia with lumbar loss of pain sensation and presence of perineal altered sensation.
Diagnosis is usually confirmed by an MRI scan or CT scan, depending on availability. If cauda equina syndrome exists, emergency surgery is usually performed depending on the etiology discovered and the patient's candidacy for major spine surgery.
Treatments for patients with cauda equina injury are limited.
Early diagnosis can allow for preventive treatment. Signs that allow early diagnosis include changes in bowel and bladder function and loss of feeling in groin.
There remains significant uncertainty in the literature regarding the urgency for surgical intervention. The past decade has seen the emergence of the much-referred-to 48-hour limit as a possible window of safety. The ramifications of this time point are significant for early patients who may subsequently have urgent treatment delayed, and for litigation cases, after which adverse decisions are more likely to occur.
A systematic principally qualitative review of the animal and human clinical literature is presented, examining the evidence for urgent surgical decompression in CES and the much-quoted 48-hour rule.
There is significant discordance in the literature regarding whether emergency surgery improves outcomes; however, a growing consensus is the acknowledgment that biologic systems deteriorate in a continuous rather than stepwise manner. Level of neurological dysfunction at surgery (incomplete CES vs. CES with retention) is probably the most significant determinant of prognosis. Onset and duration of symptoms also are likely to have an impact, if not on overall outcome then at least on duration of neurological recovery.
There is no strong basis to support 48 hours as a blanket safe time point to delay surgery. Both early and delayed surgery may result in improved neurological outcomes. However, it is likely that the earlier the surgical intervention, the more beneficial the effects for compressed nerves, especially with acute neurological compromise 1).
The management of true cauda equina syndrome frequently involves surgical decompression. When cauda equina syndrome is caused by a herniated disk early surgical decompression is recommended.
Cauda equina syndrome of sudden onset is regarded as a medical/surgical emergency.
Surgical decompression by means of laminectomy or other approaches may be undertaken within 48 hours of symptoms developing if a compressive lesion, e.g. ruptured disc, epidural abscess, tumour or haematoma is demonstrated. This treatment may significantly improve the chance that long-term neurological damage will be avoided.
Surgery may be required to remove blood, bone fragments, a tumor or tumors, a herniated disc or an abnormal bone growth. If the tumor cannot be removed surgically and it is malignant then radiotherapy may be used as an alternative to relieve pressure, with spinal neoplasms chemotherapy can also be used. If the syndrome is due to an inflammatory condition e.g. ankylosing spondylitis, anti-inflammatory, including steroids can be used as an effective treatment. If a bacterial infection is the cause then an appropriate course of antibiotics can be used to treat it.
Cauda equina syndrome can occur during pregnancy due to lumbar disc herniation; age of mother increases the risk. Surgery can still be performed and the pregnancy does not adversely affect treatment. Treatment for those with cauda equina can and should be carried out at any time during pregnancy.
Lifestyle issues may need to be addressed post - treatment. Issues could include the patients need for physiotherapy and occupational therapy due to lower limb dysfunction. Obesity might also need to be tackled.
Physical therapy can be somewhat useful for patient’s recovery from surgery (Kennedy, Soffee, McGrath, Stephens, Walsh, & McManus, 1999).
The main focus of rehabilitation is centered on controlling the bladder and bowel functions and decreasing muscle weakness in the lower extremities.
Bowel and bladder control Rehabilitation of CES depends on the severity of the injury. If permanent damage occurs, then impairment in bladder and bowel control may result (Hodges, 2004 ).[full citation needed] Once surgery is performed, resting is required until the bladder and bowel dysfunction can be assessed (Hodges, 2004 ). Urinary catheterization may help with bladder control (Hodges, 2004). Gravity and exercise can help control bowel movement (Hodges, 2004). Pelvic floor exercises assist in controlling bowel movements (Pelvic Floor Exercises, 2010).[full citation needed] These exercises can be done standing, lying, or on all fours with the knees slightly separated (Fig. 2). Full recovery of bowel and bladder control can take as long as two years (Hodges, 2004).
Physical Therapy Physical therapist can assist in sitting stability, and transferring by working on strength training. Therapists will work on balance, gait, and transfers since muscle weakness or paralysis may occur in the lower extremities (Dawodu, 2013).[full citation needed] Additionally, electrical stimulation is also helpful to enhance muscle tone
The prognosis for complete recovery is dependent upon many factors. The most important of these is the severity and duration of compression upon the damaged nerve(s). Generally, the longer the time before intervention to remove the compression causing nerve damage, the greater the damage caused to the nerve(s).
Damage can be so severe that nerve regrowth is impossible, and the nerve damage will be permanent. In cases where the nerve has been damaged but is still capable of regrowth, recovery time is widely variable. Surgical intervention with decompression of the cauda equina can assist recovery. Delayed or severe nerve damage can mean up to several years' recovery time because nerve growth is exceptionally slow.
Review of the literature indicates that around 50-70% of patients have urinary retention (CES-R) on presentation with 30-50% having an incomplete syndrome (CES-I). The latter group, especially if the history is less than a few days, usually requires emergency MRI to confirm the diagnosis followed by prompt decompression. CES-I with its more favourable prognosis may become CES-R at a later stage.
CES affects mainly middle-aged individuals. There is a significant cost associated with hospital admissions, as CES is considered an emergent condition. CES is often concurrent with congenital or degenerative diseases and represents a high cost of care to those admitted to the hospital for surgery.
Hospital stays generally last 4 to 5 days, and cost an average of $15,000 to $17,000.
Literature search identified 27 studies of CESR patients with clear definition of surgical timing. Relative risk (RR) could not be calculated in 11 studies, leaving 16 for meta-analysis. Urinary retention related to surgical timing at 5 breakpoints: 12, 24, 36, 48, or 72 hours. Urinary outcome was classified as Normal, Fair, or Poor. Meta-analysis was performed for “Event = Fair/Poor” or “Event = Poor.” Eight studies allowed separation into CESR and incomplete CES (CESI), and 5 of these had enough data for meta-analysis to compare CESR and CESI. A random effects meta-analysis model was used because of heterogeneity across the studies. A best-evidence synthesis was performed for the 4 largest studies that had 24- and 48-hour breakpoints.
For “Event = Fair/Poor,” meta-analyses using the 5 breakpoints predicted a more likely Fair/Poor outcome for later surgery (RR range 1.77-2.19). The RR for later timing of surgery was statistically significant for 24-and 72-hour breakpoints and was elevated but not statistically significant for the other 3. For “Event = Poor,” the RR range was 1.09-5.82, statistically significant for the 36 hour breakpoint only. Meta-analysis comparing CESR patients with CESI patients predicted a Fair/Poor result for CESR (RR 2.58, 95% confidence interval 0.59-11.31). The best-evidence synthesis did not disclose reasons for differences in the results of the 4 studies.
This study supports early surgery for CES and indicates that CESR and CESI cases should not be analyzed together 2).
A report describes the circumstances of a patient with a cauda equina syndrome due to the development of a lumbar subdural CSF collection with ventral displacement of the cauda equina shortly following posterior fossa decompression for Chiari malformation Type I (CM-I). This unusual, but clinically significant, complication was successfully treated with percutaneous drainage of the extraarachnoid CSF collection. Although there are a few cases of intracranial subdural hygroma developing after surgery for CM-I, often attributed to a pinhole opening in the arachnoid, as far as the authors can determine, a spinal subdural hygroma associated with surgery for CM-I has not been recognized 3).
A 32-year-old woman with remotely repaired spinal defect who experienced subarachnoid hemorrhage and underwent anterior communicating artery aneurysm clipping. Post-operatively, she developed urinary and fecal incontinence as the sole presenting symptom of communicating post-hemorrhagic hydrocephalus. New neurological deficits in this population can also be attributed to recurrent cord tethering or syrinx, both of which were demonstrated on her lumbar spine MRI, but her incontinence resolved with external ventricular drain placement and cerebrospinal fluid diversion. There are few case reports of patients with closed neural tube defects and hydrocephalus and none in the adult population to our knowledge. Neurological change in patients with any history of spinal dysraphism may reflect altered cerebrospinal fluid dynamics affecting either end of the neuraxis 4).