Biportal endoscopic foramen magnum decompression and C1 posterior arch resection for Chiari malformation type I: Technical note
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Updated: Nov 4, 2026
Uniportal Endoscopic Cervical Decompression For Myelopathic Spinal Stenosis
Published on: June 30, 2026
Héctor Alonso Tirado-Ornelas1, Silvia Loretto Tirado-Ornelas2, Alejandro Esparza-Guinea3
1Department of Neurosurgery, Hospital de Especialidades, Centro Médico Nacional de Occidente, Guadalajara, Mexico.
Background:
Chiari malformation type I is commonly treated with posterior fossa decompression and C1 posterior arch resection to restore cerebrospinal fluid flow at the craniocervical junction. Although open microsurgical decompression remains the standard approach, minimally invasive techniques may reduce soft-tissue disruption and postoperative morbidity. Biportal endoscopy may provide adequate visualization and instrument maneuverability at the craniocervical junction.
Methods:
A 60-year-old female presented with a 2-year history of progressive Valsalva-induced occipital headache and bilateral upper-limb paresthesias. Magnetic resonance imaging demonstrated a 5.7 mm descent of the cerebellar tonsils without syringomyelia. The patient underwent biportal endoscopic suboccipital decompression and partial C1 posterior arch resection using a 30° endoscope, high-speed burrs, Kerrison rongeurs, radiofrequency, and continuous saline irrigation. No dural opening or duraplasty was performed.
Results:
The operative time was 135 min, with minimal blood loss and no intraoperative complications. Postoperative CT confirmed adequate osseous decompression, including a 21 × 22 mm suboccipital craniectomy and a 10 mm C1 posterior arch resection. Postoperatively, the patient improved clinically without complications and was discharged on postoperative day 2.
Conclusion:
Biportal endoscopic foramen magnum decompression with C1 posterior arch resection appears feasible in selected adult patients with Chiari malformation type I.
