Definition and Overview

• Posterior Fossa Syndrome (PFS): A constellation of neurological and behavioral symptoms occurring in children following posterior fossa tumor resection.
• Incidence: Occurs in approximately 8% of children undergoing posterior fossa tumor surgery.
• Etiology:
  • Damage to the cerebellum and cerebello-thalamo-cortical pathways.
  • Post-surgical edema, ischemia, or disruption of white matter tracts.
  • Affects structures like the dentate nuclei, superior cerebellar peduncles, and their projections.

Key Clinical Features

1. Cerebellar Dysfunction

   • Ataxia (truncal and appendicular).
   • Dysmetria.
   • Impaired balance and coordination.

2. Oculomotor Dyspraxia

   • Difficulty initiating or coordinating eye movements.
   • Poor smooth pursuit or saccades.

3. Oral Motor Dyspraxia

   • Impaired motor planning affecting speech and swallowing.
   • Contributes to mutism and dysarthria.

4. Mutism

   • Commonly presents 1–2 days post-surgery.
   • Associated with the interruption of cerebello-thalamo-cortical pathways.
   • Often transient, with gradual recovery over weeks to months.

5. Dysarthria

   • Acute Phase: Up to 30% of children exhibit dysarthria postoperatively.
   • Features: Distorted vowels, slow speech rate, voice tremor, and monopitch.
   • Comparison with Adult Ataxic Dysarthria: Pediatric cases show distinct features, such as persistent deficits in consonant production, pitch, and rate.

6. Emotional Lability

   • Unpredictable mood swings and heightened emotional sensitivity.

Neurophysiological and Neuropsychological Impacts

• Speech and Language Recovery:
  • Long-term deficits include mild dysarthria, affecting consonant production, pitch, and rate.
  • Mutism is a marker of poorer prognosis with a higher likelihood of chronic dysarthria.
• Cognitive and Behavioral Changes:
  • Executive dysfunction, attention deficits, and processing speed delays.
  • Possible association with cerebellar cognitive affective syndrome (CCAS).

Pathophysiology

• Involvement of Dentate-Thalamocortical Pathways:
  • Disruption of efferent signals from the cerebellum to cortical speech centers.
• Bilateral Cerebellar Dysfunction:
  • Leads to disorganized motor planning and coordination.

Risk Factors

• Younger age at surgery.
• Larger tumor size or midline tumors (e.g., medulloblastoma).
• Surgical approach disrupting the cerebellar vermis.

Management

1. Immediate Postoperative Care:

   • Multidisciplinary team (neurology, neurosurgery, rehabilitation).
   • Close monitoring for signs of increased intracranial pressure or neurological deterioration.

2. Rehabilitation Strategies:

   • Speech Therapy:
     • Focus on oral-motor control, articulation, and compensatory strategies.
   • Occupational and Physical Therapy:
     • Address ataxia, balance, and motor coordination deficits.
   • Psychological Support:
     • Address emotional lability and cognitive-behavioral issues.

3. Long-term Monitoring and Support:

   • Periodic assessments of speech, motor function, and neuropsychological outcomes.
   • Coordination with educational teams to address cognitive and behavioral challenges.

Prognosis

• Recovery of mutism and dysarthria is often prolonged (weeks to months).
• Even in non-mute children, mild dysarthria may persist long-term.
• Mutism is associated with a poorer long-term prognosis.
• Speech recovery differs from adults with ataxic dysarthria in terms of rate, pitch modulation, and vowel/consonant articulation.
• Comprehensive rehabilitation improves outcomes, though residual deficits may remain.

Posterior Fossa Syndrome is a multifaceted postoperative complication with significant impacts on motor, speech, cognitive, and emotional functions. Early recognition, a multidisciplinary approach, and long-term rehabilitation are crucial to optimizing outcomes and quality of life for affected children.