# Congenital hypoplasia of the posterior arch of the atlas accompanied with cervical high-intensity intramedullary lesions: a case report

## TL;DR

A rare case of a spinal bone defect in the atlas caused neurological symptoms, and surgery helped improve the patient's condition.

## Contribution

Highlights a rare cause of neurological symptoms and the effectiveness of posterior arch resection in such cases.

## Key findings

- The patient had congenital hypoplasia of the posterior arch of C1 with high-intensity spinal cord lesions.
- Symptoms improved after surgical resection of the posterior arch of C1.
- Detailed imaging is crucial for diagnosing and managing such rare spinal conditions.

## Abstract

Congenital hypoplasia of the posterior arch of the atlas (C1) is uncommon and typically asymptomatic. A 49-year-old woman presented with a 2-year history of recurrent vertigo attacks. One month before admission, she began to have weakness in both lower extremities and unsteady walking, with chest tightness and shortness of breath after walking. She did not have any history of trauma. Cervical spine imaging revealed partial hypoplasia of the posterior arch of C1, midline cleft of the anterior arch, and cervical high-intensity intramedullary lesions. We used a posterior, suboccipital midline approach to resect the posterior arch of C1. This case underscores the importance of differential diagnosis, detailed imaging examinations should be performed to properly assess the stability of the atlantoaxial spine. In patients with neurological symptoms but no severe spinal cord compression, isolated posterior arch should be considered an potential cause of symptoms, and posterior arch resection is effective.