Complications of Conus Medullaris Syndrome
The most significant complications of conus medullaris syndrome include bladder dysfunction, bowel dysfunction, sexual dysfunction, sensorimotor disturbances of the lower limbs, and progressive musculoskeletal deformities.
Neurological Complications
- Bladder dysfunction is one of the most prominent and early complications, presenting as urinary retention, urgency, or incontinence 1
- Bowel dysfunction commonly manifests as early onset fecal incontinence 1
- Sexual dysfunction is a frequent complication that significantly impacts quality of life 2, 3
- Lower extremity weakness and sensory disturbances of variable extent, most marked in the S1 and S2 segments but potentially extending as high as L4 4
- Perineal and perianal sensory impairment (S3-S5 segments) is a characteristic finding 4
- Pain in the buttocks and posterior thighs can be a prominent symptom, particularly in cases of conus medullaris infarction 4
Autonomic Complications
- Autonomic changes can lead to skin becoming thin, shiny, and hairless in the affected areas with long-standing disease 1
- Neurogenic bladder can progress to urinary tract infections, vesicoureteral reflux, and potential kidney damage if not properly managed 2
- Autonomic dysreflexia may occur in higher lesions affecting the conus medullaris 3
Musculoskeletal Complications
- Progressive musculoskeletal deformities including scoliosis can develop in untreated or long-standing cases 1
- Muscle atrophy becomes apparent over time, particularly in the lower extremities 1
- Orthopedic deformities of the feet and spine may develop as late complications 1
Long-term Neurological Sequelae
- Permanent neurological deficits are common, with variable recovery of function over weeks to months 4
- Mixed upper motor neuron and lower motor neuron syndrome may develop in patients with conus medullaris injuries, unlike cauda equina injuries which present as pure lower motor neuron injuries 3
- Progressive retrograde death of both autonomic and motor neurons may contribute to worsening neurological deficits over time 2
Rare Complications
- In some cases, a holocord syrinx can develop, potentially extending to the level of the medulla (syringobulbia), causing unusual symptoms such as dysphagia and hiccups 5
- Hydrocephalus can be a rare complication when associated with certain pathologies affecting the conus medullaris 6
Functional Outcomes
- Despite surgical intervention, persistent bowel, bladder, and sexual dysfunctions are common 3
- Most patients maintain ambulatory motor function despite other neurological deficits 3
- Partial return of function may occur over a period of weeks in some cases, particularly with prompt treatment 4
Management Considerations
- Early diagnosis and treatment are crucial to prevent long-term neurological deficits 7
- Posterior decompression and stabilization offers at least equivalent neurological outcomes compared to nonoperative or anterior approaches for traumatic causes 3
- Neuropathic pain may require management with medications such as amitriptyline or pregabalin, which carry their own potential side effects including dizziness, somnolence, and anticholinergic effects 8, 9
Understanding these complications is essential for proper management and setting realistic expectations for patients with conus medullaris syndrome.