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posterior_fossa_decompression [2025/07/10 14:03] – administrador | posterior_fossa_decompression [2025/07/10 14:04] (current) – [Indications] administrador | ||
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[[Posterior Fossa Decompression Indications]]. | [[Posterior Fossa Decompression Indications]]. | ||
+ | |||
+ | ===== Posterior fossa decompression Technique ===== | ||
+ | |||
+ | ===== Surgical Technique ===== | ||
+ | |||
+ | ==== 1. Patient Positioning ==== | ||
+ | * **Prone** or **Park bench** position | ||
+ | * Head fixed in Mayfield clamp | ||
+ | * Slight neck flexion to expose the occipitocervical junction without kinking the medulla | ||
+ | |||
+ | ==== 2. Incision and Exposure ==== | ||
+ | * Midline **occipital incision** from inion to C2 spinous process | ||
+ | * Subperiosteal dissection to expose: | ||
+ | - Occipital bone | ||
+ | - Posterior arch of C1 | ||
+ | - Superior lamina of C2 (in extended decompressions) | ||
+ | |||
+ | ==== 3. Bony Decompression ==== | ||
+ | * **Suboccipital craniectomy** | ||
+ | - Typically 2–3 cm wide, exposing the foramen magnum | ||
+ | * **C1 laminectomy** (partial or complete) | ||
+ | - Relieves compression at cervicomedullary junction | ||
+ | |||
+ | ==== 4. Dural Opening (optional, case-dependent) ==== | ||
+ | * Y- or U-shaped durotomy | ||
+ | * Allows direct decompression of cerebellar tonsils and posterior fossa contents | ||
+ | |||
+ | ==== 5. Duraplasty ==== | ||
+ | * Performed using **autologous graft**, **synthetic patch**, or **pericranium** | ||
+ | * Prevents postoperative CSF leak and improves subarachnoid flow | ||
+ | |||
+ | ==== 6. Tonsillar Reduction (select cases) ==== | ||
+ | * **Coagulation** or **subpial resection** of cerebellar tonsils | ||
+ | * Only in symptomatic, | ||
+ | |||
+ | ==== 7. Closure ==== | ||
+ | * Watertight dural closure critical | ||
+ | * Muscle and skin layers closed in standard fashion | ||
+ | * Subfascial drain optional | ||
+ | |||
+ | ===== Postoperative Considerations ===== | ||
+ | * Monitor for CSF leak, pseudomeningocele, | ||
+ | * Serial MRI to assess decompression and syrinx resolution (if present) | ||
+ | * Pain control and gradual mobilization | ||
+ | |||
+ | ===== Complications ===== | ||
+ | * CSF leak | ||
+ | * Pseudomeningocele | ||
+ | * Meningitis | ||
+ | * Cerebellar ptosis (over-decompression) | ||
+ | * Neurological worsening (rare) | ||