Massive postoperative cerebral swelling following cranioplasty.

Sir,

Removal of a variable amount of skull bone, known as descompressive craniectomy (DC), is widely performed in patients suffering from medically refractory elevation of intracranial pressure (ICP) and is known to improve the clinical outcome. Patients who survive after DC need to undergo a second procedure for cranial reconstruction or cranioplasty (CP) and they can suffer some types of complications. We report a case of a patient who developed massive postoperative cerebral swelling and subsequently died.

A 17-year-old male patient was admitted after being hit by a car and resuscitated for 45 minutes after cardiac arrest in situ. A total body Computed Axial Tomography (CT) scan showed, left parietal subdural hematoma, subarachnoid hemorrhage in the posterior area, and generalized edema. Initially he remained sedated and relaxed due to intracranial hypertension secondary to cerebral edema, requiring DC five days after brain trauma, achieving normalized ICP after the surgical procedure. He was transferred to the ward a month later, alert and oriented, with a Glasgow Score Coma (GCS) of 15 points.

Two months later, he was scheduled for CP, arriving at the Operating Room conscious and with 15 points on GCS. The CT prior to the surgery [Figure 1a] only showed a hypodense lesion with cerebrospinal fluid density in the right frontal lobe, in relation to the residual encephalomalacia area, the presence of subdural hygromas in the sickle brain, other collections outside the extra-axial space, underlying the surgical plasty area, and a ventricular system of normal size and morphology.

Figure 1

(a) CT prior to cranioplasty (a month-and-a-half after the craniectomy), (b) CT after cranioplasty (massive brain edema)

The CP was performed without intraperioperative complications, but in the immediate postoperative period, the GCS fell till 8, with clinical signs of intracranial hypertension with unresponsive bilateral mydriatic pupils, hypertension and bradycardia. A cranial CT scan was displayed, showing radiological signs of massive cerebral edema [Figure 1b]. He was taken to the Operating Room for reoperation; expansion of the craniotomy and bifrontal lobectomy were performed, and despite being operated the patient evolved to brain death twelve hours later.

Patients who survive after DC need to undergo a second procedure for cranial reconstruction or CP. Complications following CP, including epidural or subdural hematoma, wound healing disturbance, abscess, hygroma, cerebrospinal fluid fistula, infection, and bone graft resorption have been considered as a significant cause of postoperative morbidity.[1] Some authors have found that up to 33% of the patients who underwent CP have suffered some type of complication such as wound breakdown, intracranial hemorrhage, bone resorption, sunken CP, or the early finalization of it by intraoperative hypotension and bradycardia.[2]

The optimal timing of CP still remains controversial. Some authors have evaluated the outcome and complication rates of different cranioplasty procedures, depending on the timing of CP and they have found that ultra-early cranioplasty (until six weeks) by reimplanting the patient's own, previously removed and frozen skull bone, was a safe and successful strategy.[3] However, other authors have concluded that, if CP was performed early (≤ 2 months) the patients suffered significantly more complications compared to the patients treated later (> 2 months).[4]

The exact pathophysiological mechanism behind massive swelling and sudden death following CP is poorly understood. The underlying cause must be related to a failure in the autoregulatory process. The brain, which is used to atmospheric pressure when subjected to a CP, appears to shift toward negative pressure, causing a rapid expansion of the brain to fill the defect within the skull.[5]

In conclusion, this article highlights an important complication that we think is under-reported in the current literature.[67] Patients undergoing a bifrontal craniectomy are at high risk for postcranioplasty complications, including the need for reoperation or death.