# Unresponsiveness to Chiari Malformation Type I Surgery Can Be Related to the Accompanying Chiari Network

## TL;DR

Some patients with Chiari malformation type 1 may not improve after surgery if they also have a patent foramen ovale and Chiari network, highlighting the need for thorough cardiac evaluation.

## Contribution

The paper highlights a novel association between unresponsiveness to CMI surgery and the presence of a patent foramen ovale and Chiari network.

## Key findings

- A patient with CMI and persistent symptoms was found to have a large patent foramen ovale and Chiari network.
- Symptoms resolved after patent foramen ovale closure, suggesting it was the primary cause.
- The case emphasizes the importance of cardiac evaluation before CMI surgery for dizziness-related complaints.

## Abstract

Surgical treatment is indicated for Chiari malformation type 1 (CMI) with tonsillar descent (TD) of >5 mm and other clinical manifestations. However, some patients remain unresponsive to surgery; this is an active topic of discussion. A patient presented to the emergency department with dizziness and an impaired gait. He had a history of hypertension. Magnetic resonance investigations revealed a 9-mm TD and cervical syringomyelia. There was no evidence of interatrial septum pathology on transthoracic echocardiography performed preoperatively. Although his complaints were attributed to CMI and surgery was performed, his symptoms remained persistent. Two years later, when the patient’s dizziness increased, a posterior fossa transient ischemic attack (TIA) was suspected. A large patent foramen ovale (PFO) and Chiari network (CN) were also detected on transesophageal echocardiography. His complaints were resolved following PFO closure. Our case suggests that neurosurgeons should be informed about the results of the companionship of a PFO and CN. Before deciding on CMI surgery for patients with only dizziness complaints, a detailed investigation of accompanying cardiac pathologies is paramount to ensure accurate diagnosis and treatment.