What are the symptoms and treatment options for Spina bifida occulta?

Symptoms of Spina Bifida Occulta

Spina bifida occulta is often asymptomatic and discovered incidentally, but when symptomatic, it most commonly presents with urological dysfunction, neurological deficits, and lower limb deformities, particularly when associated with tethered cord syndrome. 1, 2, 3

Clinical Presentation Patterns

Asymptomatic Presentation

• Many patients with spina bifida occulta remain completely asymptomatic throughout life, as it represents only a bony defect of the vertebral arch without neural element protrusion 4
• The condition is characterized by incomplete closure of vertebral arches without protrusion of neural elements, distinguishing it from the more severe cystic forms 1

Symptomatic Presentations

Urological Symptoms (most common when symptomatic):

• Urinary incontinence and enuresis can occur at all ages 2
• Bladder dysfunction may be the sole initial complaint in some patients, particularly young adults, making diagnosis challenging 2
• Detrusor hyperreflexia occurs in approximately 42% of symptomatic patients 2
• Low compliance detrusor is present in 67% of cases 2
• Large post-micturition residuals may develop 2
• Vesicoureteral reflux can occur, though less commonly than in spina bifida cystica 2

Neurological Deficits:

• Present in 83.9% of symptomatic patients with tethered cord 3
• Dominant upper motor neuron signs are characteristic of the occult form, contrasting with the cystic form 2
• Muscle weakness, particularly in lower extremities 3
• Absent bulbocavernosus reflex in 56% of cases 2
• Absent anal reflex in 57% of cases 2
• Poor anal tone may be present 3

Musculoskeletal Manifestations:

• Lower limb deformities occur in 38.7% of symptomatic patients 3
• Chronic low back pain can be the predominant symptom, sometimes persisting for years before diagnosis 5
• Pain radiating to the legs may occur 5

Pain Syndromes:

• Chronic low back pain may be the presenting complaint, potentially delaying diagnosis for extended periods (up to 2 years in documented cases) 5
• Non-specific clinical symptoms can significantly hinder prompt diagnosis 5

Diagnostic Challenges

A critical pitfall is that urinary symptoms may be the only presenting complaint without obvious neurological abnormalities, particularly in young adults, making spinal imaging essential when urological dysfunction is unexplained 2. The non-specific nature of symptoms like chronic low back pain can lead to misdiagnosis and inappropriate initial treatment (such as epidural steroid injections) that yields suboptimal outcomes 5.

Recommended Diagnostic Approach

Initial Assessment:

• Baseline renal and bladder ultrasound to assess for congenital anomalies or early urological dysfunction 1
• Spinal MRI is required and recommended for characterization of intraspinal and perispinal abnormalities, particularly in cases of chronic lower back pain failing to improve with expected management 1, 5
• Careful neurological examination focusing on lower extremity motor function, reflexes (bulbocavernosus and anal), and sphincter tone 2, 3

Urological Evaluation:

• Regular urodynamic testing to detect bladder dysfunction before upper tract changes develop 6, 1
• Assessment of post-void residual volumes 1
• Evaluation for vesicoureteral reflux 2

Treatment Considerations

Conservative Management:

• Clean intermittent catheterization may be initiated if post-void residual volumes exceed 30 ml consistently 1
• Antimuscarinic medications for detrusor overactivity 1
• Unlike myelomeningocele, most patients with spina bifida occulta do not require immediate urological intervention unless specific abnormalities are detected 1

Surgical Intervention:

• Untethering should be performed immediately once symptomatic lumbosacral cord tethering is evident, irrespective of age 3
• Younger age at surgery (≤2 years) is a positive prognostic factor for symptom improvement (odds ratio 22.0) 3
• Surgical intervention is indicated for those at risk for renal deterioration or who fail medical management 6
• Intraoperative neurophysiological monitoring can assist in identifying the appropriate decompression level 5

Expected Outcomes:

• Untethering can stabilize symptoms in 45.2% and improve symptoms in 54.8% of patients 3
• Complete symptom resolution occurs in 45.2% of cases 3
• Sphincter dysfunction and muscle weakness are more likely to improve or resolve than limb deformities 3
• Young children (before 2 years old) have the highest chance of favorable outcome 3

Long-term Surveillance

Ongoing Monitoring Requirements:

• Continued surveillance for tethered cord syndrome is indicated in all patients, as it can develop later in childhood 6, 1
• Regular monitoring for development of neurological symptoms is essential 1
• Retethering is a main concern during follow-up, particularly for more complicated cases 3
• Urological issues can be a significant source of morbidity and mortality, with chronic kidney disease due to poor bladder dynamics being a serious long-term complication 6

Transitional Care:

• Adequate transitional care from pediatric to adult services is extremely important 6
• Multidisciplinary care involving neurosurgery, urology, orthopedics, and physical medicine is beneficial 1