Surgical Scoliosis Correction in Chiari-I Malformation with Syringomyelia Versus Idiopathic Syringomyelia

Scoliosis in adult Type 1 Chiari malformation with syringomyelia patients: from pathogenesis to treatment

The pathogenesis of type I Chiari malformation (CIM) is complex and remains unclear. The theory of posterior cranial fossa incompatibility has gained widespread acceptance in recent years. In the patients with CIM combined with syringomyelia, scoliosis is a common occurrence, with severe cases often leading to complications that necessitate surgical intervention. Scoliosis of various etiologies manifests as a three-dimensional structural spinal deformity. The etiology of scoliosis secondary to Chiari malformation is well-defined, and its imaging characteristics resemble those of idiopathic scoliosis. Vertebral rotation plays a critical role in the onset and progression of the deformity. However, spinal orthopaedic surgery in these patients is more challenging and hazardous due to the Chiari malformation and associated spinal cord abnormalities. Accurate preoperative assessment of scoliosis, Chiari malformation, and syringomyelia (SM), along with strategic planning of surgical approaches and fusion segment selection, is essential for improving patient outcomes and prognosis. In adults, CIM presents with more severe clinical manifestations compared to children, mainly including brainstem and cranial nerve compression, spinal-related syndromes, cerebellar injury syndromes, and hydrocephalus. Consequently, scoliosis deformities are often overlooked. Currently, there are limited reports on the efficacy of spinal correction surgery in adult patients with scoliosis associated with adult Type 1 Chiari malformation with syringomyelia (CIM-SM). Additionally, it remains uncertain whether and when syringomyelia should be addressed in these patients. This study aims to review previous research and explore whether intervention for Chiari malformation and syringomyelia should precede spinal orthopaedic surgery, as well as to evaluate the efficacy of spinal correction procedures.

The Role of Neurophysiology in Managing Patients with Chiari Malformations

Chiari malformation type 1 (CM1) includes various congenital anomalies that share ectopia of the cerebellar tonsils lower than the foramen magnum, in some cases associated with syringomyelia or hydrocephalus. CM1 can cause dysfunction of the brainstem, spinal cord, and cranial nerves. This functional alteration of the nervous system can be detected by various modalities of neurophysiological tests, such as brainstem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, electromyography and nerve conduction studies of the cranial nerves and spinal roots, as well as brainstem reflexes. The main goal of this study is to review the findings of multimodal neurophysiological examinations in published studies of patients with CM1 and their indication in the diagnosis, treatment, and follow-up of these patients, as well as their utility in intraoperative monitoring.