Surgical Interventions for Patients With Chiari Malformation

Publication Date: August 31, 2023
Last Updated: September 29, 2023

Summary of Recommendations

In patients with symptomatic CM1 malformation (with or without syrinx), either posterior fossa decompression (PFD) or posterior fossa decompression with duraplasty (PFDD) may be utilized as a first line treatment to improve pre-operative symptoms. (C)

In patients undergoing posterior fossa decompression surgery for treatment of CIM and syrinx, surgeons may perform resection or reduction of cerebellar tonsil tissue to improve syrinx and/or symptoms. (C)

Intraoperative neuromonitoring in patients undergoing decompression for CIM may be used during surgery. (C)

Surgeons may perform additional neurosurgical intervention 6 to 12 months following surgical treatment of CIM with syringomyelia in patients that have not demonstrated radiographic improvement. (B)

Patients undergoing surgery for CIM who experience symptom resolution may be monitored for symptom or imaging changes. (C)

Recommendation Grading


  • CCOS: Chicago Chiari Outcome Scale
  • CIM: Chiari I Malformation
  • CSF: Cerebrospinal Fluid
  • IONM: Intraoperative Neuromonitoring
  • MRI: Magnetic Resonance Imaging
  • PFD: Posterior Fossa Decompression
  • PFDD: Posterior Fossa Decompression With Duraplasty
  • SDB: Sleep-disordered Breathing
  • SSEPs: Somatosensory Evoked Potentials


The information in this patient summary should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.



Patients With Chiari Malformation: Surgical Interventions

Authoring Organization

Publication Month/Year

August 31, 2023

Last Updated Month/Year

November 2, 2023

Document Type


Country of Publication


Document Objectives

Chiari malformation type I (CIM) diagnoses have increased in recent years. Controversy regarding the best operative management prompted a review of the literature to offer guidance on surgical interventions.

Target Patient Population

All patients with Chiari Malformation

Target Provider Population

Neurologists, neurosurgeons, and other allied clinicians treating adults and children with Chiari Malformation

Inclusion Criteria

Male, Female, Adolescent, Adult, Child, Infant, Older adult

Health Care Settings

Hospital, Outpatient, Operating and recovery room

Intended Users

Nurse, nurse practitioner, physician, physician assistant


Treatment, Management

Diseases/Conditions (MeSH)

D001139 - Arnold-Chiari Malformation


Chiari Malformation, Chiari I Malformation

Source Citation

Pattisapu JV, Ackerman LL, Infinger LK, Maher CO, Quinsey C, Rocque BG, Silberstein H, Jackson EM, Jernigan S, Niazi T, Qaiser R, Raskin JS, Vachhrajani S, Bauer DF. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Surgical Interventions. Neurosurgery. 2023 Oct 1;93(4):731-735. doi: 10.1227/neu.0000000000002635. Epub 2023 Aug 30. PMID: 37646504.