A growing skull fracture (GSF), also known as a posttraumatic leptomeningeal cyst, is a rare post-traumatic skull defect in which a diastatic fracture enlarges progressively due to underlying dural tear and herniation of brain/arachnoid. The pulsatile forces of the growing brain cause the bone defect to widen, producing scalp swelling, neurological deficits, and progressive bone erosion.

 

Q. What is the pathophysiology of growing skull fracture?
 

The key pathological event is a dural laceration at the time of head injury in infants or young children whose skull bones are thin and pliable. The arachnoid and brain herniate outward through the dural defect. Each pulse of CSF creates outward pressure, preventing dural healing and mechanically widening the bone gap. Over time, the bone margins remodel outward and cortical tissue beneath the defect becomes gliotic, porencephalic, or cystic.

 

Q. What is the classification of growing skull fractures?
 

GSF can be classified into three types based on the intracranial pathology:

 

Type I – Glial Type

Herniation of gliotic brain tissue through the dural tear

No clear CSF cavity

Represents cortical damage with outward bulging
 

Type II – Leptomeningeal / Arachnoid Cyst Type

Herniation of arachnoid and CSF through the fracture

Formation of a subgaleal CSF-filled sac

Classical “leptomeningeal cyst”
 

Type III – Ventricular Type

Herniation of ventricular system or porencephalic cyst through the dural defect

Often associated with a large cortical defect and severe underlying tissue loss

 

This classification is clinically relevant because Type III has the worst prognosis and requires more extensive repair.

 

Q. How does a child with a growing skull fracture present?
 

Presentation often occurs weeks to months after head trauma. Parents may notice a soft, pulsatile swelling over a fracture site that progressively enlarges. Neurological symptoms include seizures, focal deficits, delayed milestones, irritability, or failure to thrive. The defect is commonly parietal. Progressive bone diastasis and scalp bulging are characteristic.

 

Q. How is growing skull fracture diagnosed?
 

CT shows widening of a fracture line with underlying porencephalic changes or cystic cavitation. MRI is essential to evaluate the dural defect, herniated brain or CSF, gliosis, and ventricular involvement. MRI also defines the need for cortical repair, duraplasty, and cranioplasty.

 

Q. What are the indications for surgery in growing skull fracture?
 

All growing skull fractures require early surgery, because continued pulsation enlarges the defect and worsens neurological outcome. Indications include:

Progressive scalp swelling

Bone diastasis

Evidence of dural defect

Herniation of brain or CSF

Seizures or neurological deterioration

Cosmetic deformity

 

Q. How will you counsel parents before surgery?
 

I will explain that the defect enlarges because the dura is torn and the brain or arachnoid herniates outward. Surgery is necessary to repair the dura, stop enlargement, improve cosmetic appearance, and prevent neurological decline. I will discuss risks such as CSF leak, infection, seizures, and need for cranioplasty. I will reassure them that early surgery usually provides excellent results and that long-term neurological stabilization is expected if deficits have not become fixed.

 

Q. How will you surgically treat a growing skull fracture? 

 

I will position the child supine with the head turned to expose the lesion and secure all pressure points. After a wide antiseptic preparation, I will make an incision incorporating the previous scar or centered over the defect. I will raise a myocutaneous flap, protecting the periosteum, and expose the widened bony defect. I will inspect the fracture margins and extend the craniectomy circumferentially until I reach healthy bone with firm edges.

 

Under the microscope, I will carefully dissect the scalp and pericranium from the underlying arachnoid or cyst. I will then open the cranial defect and identify the dural tear. I will free the herniated neural or arachnoid tissue circumferentially, releasing any adhesions between brain and dura or bone margins. If gliotic or nonviable brain tissue is present, I will gently debulk it only to the extent required to reduce distortion, taking care not to injure functional cortex.

 

I will then mobilize the dural edges widely by dissecting them from the inner table of the bone. The goal will be to obtain a full circumference of free dura for closure. The dural tear is often irregular and retracted, so I will freshen the margins and create a defect suitable for grafting. I will perform a generous duraplasty with pericranium, fascia lata, or synthetic graft, ensuring a watertight closure to eliminate the pulsatile forces that caused the expansion.

 

Once the dura is fully reconstructed, I will reconstruct the bone defect. For small or moderate defects, I will fashion an autologous split-thickness calvarial graft; for larger defects, I will use bone grafts or titanium mesh. I will contour the cranioplasty to restore normal skull shape. I will achieve meticulous hemostasis and irrigate thoroughly, then close the muscle, fascia, subcutaneous tissue, and skin in layers without tension.

 

Postoperatively, I will monitor for seizures, CSF leak, scalp swelling, and neurological recovery. MRI follow-up will confirm dural integrity and the absence of recurrent cyst formation.

 

Q. What are the perioperative complications of growing skull fracture surgery?
 

Risks include CSF leak, infection, epidural or subdural collection, seizures, injury to underlying cortex during dissection, hemorrhage from diploic veins, inadequate dural mobilization, and incomplete repair leading to recurrence. Cranioplasty complications include contour asymmetry or graft resorption.

 

Q. What postoperative complications may occur?
 

These include persistent swelling from residual CSF collections, new neurological deficits, seizure recurrence, pseudomeningocele, infection, cosmetic deformity, or failure of bone grafts. Rarely, children may develop re-tethering at the dural graft or progressive porencephaly.

 

Q. Are there recent advancements in managing growing skull fractures?
 

Newer techniques emphasize microsurgical duraplasty, improved graft materials (pericranial flap, collagen matrix), endoscopic assistance for minimally invasive repairs in select cases, and early postoperative MRI to confirm dural integrity. High-resolution imaging helps in detecting associated porencephaly and planning reconstruction. The emphasis is on early intervention to prevent progressive neurological decline.