What are the potential complications of hemispherotomy in pediatric patients with severe, intractable epilepsy?

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Complications of Hemispherotomy

Hemispherotomy carries a low but significant risk of serious complications, with mortality occurring in approximately 2.5% of cases, hydrocephalus requiring shunt placement in 5%, and acute worsening of hemiparesis universally in all patients, though most complications are manageable and the procedure remains highly effective for seizure control. 1, 2

Mortality and Life-Threatening Complications

  • Death occurs in approximately 2.5% of cases (1 death in 40 patients in a major pediatric series), representing the most severe potential outcome. 1
  • Serious complications requiring intervention develop in approximately 5% of patients, though the specific nature of these complications varies by surgical technique and patient characteristics. 1

Hydrocephalus

  • Hydrocephalus requiring ventriculoperitoneal shunt placement occurs in approximately 5% of patients (2 out of 40 cases in one series), representing one of the most common serious postoperative complications. 1
  • This complication necessitates additional surgical intervention and long-term shunt management with associated risks of infection and malfunction. 1

Neurological Deficits

  • Acute worsening of pre-existing hemiparesis occurs universally (100%) in all patients immediately following surgery, though this is expected given the nature of the procedure. 2
  • The acute motor deterioration is typically transient, with most patients returning to baseline or near-baseline motor function during recovery. 2
  • Patients with hemispheric brain lesions already have abnormal neurological development preoperatively, so the additional deficit must be weighed against seizure control benefits. 2

Seizure Recurrence

  • Incomplete disconnection of the corpus callosum represents one of the most important technical causes of seizure recurrence, occurring in approximately 7.5% of cases (3 out of 40 patients). 3
  • Bilateral focal metabolic abnormalities on FDG-PET serve as an independent predictor of seizure recurrence after hemispherotomy, emphasizing the importance of confirming unilateral disease preoperatively. 4
  • Subtle MRI abnormalities extending beyond the disconnected hemisphere or abnormalities in the contralateral hemisphere may influence surgical outcome and predict seizure recurrence. 4

Etiology-Specific Complication Risks

  • Hemimegalencephaly cases demonstrate the worst seizure outcomes and highest frequency of surgical complications compared to other etiologies such as Rasmussen encephalitis, stroke, or cortical dysplasia. 3
  • The etiology of unilateral hemispheric lesions is closely related to both seizure outcomes and complication rates, with congenital malformations carrying higher risk than acquired lesions. 3

Technical Considerations to Minimize Complications

  • Modern disconnective hemispherotomy techniques (peri-insular, vertical, trans-sylvian) have largely replaced anatomical hemispherectomy to reduce operative risks and morbidity. 2, 5
  • Complete disconnection is essential—incomplete callosal section should be carefully evaluated as a cause of surgical failure and can be identified on postoperative imaging. 3
  • Hippocampal resection versus disconnection does not affect complication rates or seizure outcomes, suggesting that less extensive resection may be equally effective. 6

Common Pitfalls to Avoid

  • Failing to confirm unilateral disease with FDG-PET preoperatively, as bilateral metabolic abnormalities predict poor outcomes and seizure recurrence. 4
  • Incomplete disconnection of all commissural fibers, particularly the corpus callosum, which leads to persistent seizures. 3
  • Delaying surgery in appropriate candidates, as early intervention in conditions like Sturge-Weber syndrome and hemimegalencephaly may lead to better seizure control and cognitive development. 4

References

1
Research

Hemispherectomy in the treatment of pediatric symptomatic epilepsy of children.

Zhurnal voprosy neirokhirurgii imeni N. N. Burdenko, 2016

2
Research

Outcome of hemispheric surgeries for refractory epilepsy in pediatric patients.

Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery, 2007

4
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

6
Research

Hippocampal resection during hemispherotomy: is it needed?

Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery, 2024

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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