From the Guidelines
Conus medullaris syndrome is a neurological condition characterized by damage to the conus medullaris, the lower end of the spinal cord, resulting in symmetric pain, weakness, and sensory loss in the lower extremities, along with early bladder and bowel dysfunction. This syndrome typically occurs due to trauma, tumors, infections, or vascular problems affecting the conus medullaris, which is located at approximately the L1-L2 vertebral level 1. The symptoms of conus medullaris syndrome can be similar to those of cauda equina syndrome, which is caused by compression of the nerve roots in the lumbar spine, but the two conditions have distinct differences in terms of their anatomy and clinical presentation 1.
Key Characteristics of Conus Medullaris Syndrome
- Symmetric pain, weakness, and sensory loss in the lower extremities
- Early bladder and bowel dysfunction due to the involvement of the sacral segments of the spinal cord
- Treatment depends on the underlying cause, which may include surgical decompression, antibiotics, or supportive care to manage symptoms
- Comprehensive care, including urological management and bowel regimens, is often necessary to prevent complications The prognosis of conus medullaris syndrome varies based on the cause and timing of treatment, with better outcomes generally seen when intervention occurs promptly after symptom onset 1.
Diagnosis and Management
The diagnosis of conus medullaris syndrome is typically made based on a combination of clinical features and radiographic findings, including MRI or CT scans of the lumbar spine 1.
- MRI is the preferred imaging modality due to its ability to accurately depict soft-tissue pathology and assess vertebral marrow and spinal canal patency
- CT scans may be useful in certain situations, such as when MRI is not available or when there is a need to assess bony structures Treatment of conus medullaris syndrome depends on the underlying cause, but may include surgical decompression, antibiotics, or supportive care to manage symptoms 1.
- Physical therapy is often recommended to maintain muscle strength and prevent complications from immobility
- Comprehensive care, including urological management and bowel regimens, is often necessary to prevent complications and improve quality of life.
From the Research
Definition and Symptoms of Conus Medullaris Syndrome
- Conus medullaris syndrome (CMS) is a clinical neurologic syndrome caused by a conus medullaris lesion, which can manifest through a variety of symptoms including back pain, unilateral or bilateral leg pain, paresthesias and weakness, perineum or saddle anesthesia, and rectal and/or urinary incontinence or dysfunction 2.
- CMS is a heterogeneous entity with various etiologies such as trauma or a space-occupying lesion, and can cause variable symptoms and neurological deficits, usually involving the lower extremities 3.
- However, CMS without lower extremity involvement is extremely rare, and can present with symptoms such as dysuria and lumbago, with mild perineal hypoalgesia and normal motor function and lower extremity sensation 3.
Causes and Pathophysiology of Conus Medullaris Syndrome
- The conus medullaris is located at the end of the spinal cord and continues to the cauda equina, and lesions in this area can cause CMS 3.
- Traumatic injuries at the thoracolumbar junction at the terminal portion of the spinal cord and cauda equina are common causes of CMS 2.
- The pathomechanism of CMS is unclear, but it is hypothesized that radioisotope neurotoxicity might be responsible in some cases 4.
Diagnosis and Treatment of Conus Medullaris Syndrome
- Diagnosis of CMS can be made through neurological examination, magnetic resonance imaging, and postmyelographic computed tomography 3.
- Treatment options for CMS include surgical intervention, such as posterior decompression and stabilization, which can offer equivalent neurological outcomes as nonoperative or anterior approaches 5.
- Surgical treatment for CMS without lower extremity involvement caused by intradural disc herniation can be effective in resolving symptoms such as dysuria 3.
Comparison with Cauda Equina Syndrome
- CMS is a distinctive spinal cord injury that presents with varying degrees of upper motor neuron signs and lower motor neuron signs, whereas cauda equina syndrome is a pure lower motor neuron injury 6.
- The high-riding injury site for CMS is related to a more exclusive clinical representation of upper motor neuron signs, and can have a prolonged recovery period 6.