Ischemic Stroke after Cranioplasty: A rare cause of Refractory seizures

Introduction: Cranioplasty is an elective neurosurgical reconstruction of the skull facilitating both psychosocial and cognitive improvement post-craniectomy. Seizures, as a post-cranioplasty complication, has been observed at rates ranging from 2.7% - 29% ^(1,2). While several factors have been implicated in the development of post-cranioplasty seizures, ischemic events are infrequently reported.

Objective: To report a rare instance of seizure occurrence secondary to ischemic infarcts following cranioplasty.

Case report: A 24-year-old female with no comorbidities developed a left temporo-parietal Subdural haemmorhage (SDH) and Subarachnoid haemmorhage along the left temporal sulcus following a motor vehicle accident. She presented with one post-traumatic seizure and a Glasgow Coma Scale (GCS) of E1V1M5. She underwent a left fronto-temporoparietal decompressive craniectomy for a 10mm rightward midline shift. Her course was complicated by Hospital Acquired Pneumonia, pyogenic meningitis and prolonged hospitalisation. She was discharged 39 days later (GCS 11/15, anisocoria, right hemiparesis) on prophylactic anti-epileptic drugs (AED). After rehabilitation, GCS improved to 14/15.

She presented with gait disturbances 6 months later and Computed Tomography (CT) taken showed a communicating hydrocephalus. A right parietal Ventriculo-peritoneal shunt was placed. Post-procedure she recovered to GCS 15/15.

She underwent Cranioplasty with Polymethyl Methacrylate (PMMA) after 2 weeks and developed 3 episodes of generalised tonic clonic seizures, each lasting 30-60 seconds, within 3 hours of surgery. All metabolic parameters including serum electrolytes, glucose, calcium, and renal/hepatic profiles were within normal limits, excluding metabolic or systemic precipitants. CT showed a thin SDH beneath the cranioplasty site. Magnetic Resonance Imaging confirmed an acute right thalamic infarct with haemorrhage and multiple left cortical hemorrhagic foci suggesting a close temporal relation between the surgery and onset of ischemic seizures. She was prescribed Inj. Levitiracetam 1g BD,  T.Clobazam 10mg BD, T.Lacosamide 100mg BD, later escalated to 1.5g, 20mg, 200mg, respectively. Persistent seizures required sedation with Midazolam (50mcg/hour), Propofol (50mcg/hour), and Ketamine (50mcg/hour) and T.phenytoin 100mg Q8H was added. Electroencephalogram (EEG) revealed Periodic Lateralized Epileptiform Discharges from the left frontal region. Hence, sedation was stopped, and AEDs were continued. She remained seizure-free and was discharged with GCS:14/15 on the same anti-epileptics with no residual deficits.

Discussion: Cranioplasty improves cerebral blood flow (CBF) in the cortex of cranioplasty by 15-30% ⁽³⁾. The cortex beneath a craniectomy gradually progresses to cerebromalacia and loses elasticity ⁽⁴⁾. In our patient, the hemorrhagic foci in the left frontal lobe could be attributable to a sudden increase in CBF and thus, cerebral metabolism after cranioplasty. Reperfusion injury following hyperperfusion and free radicle release ⁽⁵⁾ can also result in ischemia. A sudden increase in CBF in a chronically dysfunctional brain that has lost auto-regulatory properties may result in venous stasis leading to thrombosis ⁽⁶⁾. Therefore, clinicians should maintain a high index of suspicion for ischemia in post-cranioplasty seizure patients with time-sensitive imaging, EEG, and appropriate use of AEDs.

Conclusion: A Cranioplasty-induced acute shifts in Intracranial pressure may lead to changes in CBF. Acute ischemia, thus produced, can lead to Post-Cranioplasty seizures.

Dr.Saikrithika Natarajan is an MBBS graduate from India currently working as a senior house surgeon at the neurocritical ICU of Christian Medical College, Vellore who aspires to become a neurosurgeon in the near future and wants to contribute to the neuroscience community.