Background: Myelomeningocele (MMC) is the most common open spinal dysraphism (OSD) and is typically associated with other clinical and/or radiological abnormalities. Chiari type 2 malformation (CM-II) is observed in 80% to 96.7% of patients, and approximately 80% of cases involve posterior fossa abnormalities leading to hydrocephalus. MMC patients can present with syringomyelia, which usually improves by treating hydrocephalus. However, a minority of patients develop a progressive form of syringomyelia requiring more invasive treatments. Through this retrospective observational study, our objective is to elucidate the incidence of syringomyelia, its symptomatic manifestations, and the associated radiological and clinical characteristics in pediatric patients diagnosed with myelomeningocele Methods: A retrospective analysis was conducted on the medical records of 39 pediatric patients diagnosed with myelomeningocele at a tertiary referral institute. The study encompassed individuals born between 1997 and 2022. Descriptive statistics were employed to explore epidemiological aspects and clinical features. Additionally, incidence rates of syringomyelia and its progressive variants were calculated, with a focus on their correlation with diagnoses of hydrocephalus, Chiari type 2 malformation (CM-II), and spinal cord tethering. Results: Over the last twenty-five years, the incidence of syringomyelia in pediatric patients affected by MMC was 46.2%. The incidence of its progressive forms was 16.7%. Two patients improved after the management of hydrocephalus with secondary Endoscopic Third Ventriculostomy (ETV), and only one patient required syrinx-shunting. Conclusions: The occurrence of syringomyelia among patients with myelomeningocele (MMC) in our center aligns with reported rates in existing literature. Our findings indicate that active hydrocephalus, leading to a deterioration of hindbrain herniation, appears to be a significant factor in the development of progressive symptomatic syringomyelia within this population.

Introduction- Chiari malformation type 1 (CM-1) is defined by the caudal displacement of cerebellar tonsils through the foramen magnum (cut off of 5 mm from McRae line.) In Chiari malformation type 1.5 (CM-1.5) both cerebellar tonsils and brainstem result herniated. Patient with CM may exhibit a variety of symptoms: the most common are headache and cervical pain. Associated anomalies such as syringomyelia (67-80%), hydrocephalus (10 %), craniosynostosis or tethered spinal cord may be present. Surgical treatment is not performed in asymptomatic patients, while the presence of syringomyelia represents an indication for surgical decompression. In this paper we report our experience with the use of intra-operative ultrasonography in orienting surgical decompression with or without dural opening. Methods- We retrospectively examined and selected pediatric patients with CM-1/ CM-1.5 who were managed between 2006-2020 at Giannina Gaslini Hospital. Exclusion criteria were the association with achondroplasia and with spina bifida. Results- A total of 211 pediatric patients were identified for evaluation: CM-1 accounted for 83.9% of patients and CM-1.5 for 16.1%. Syringomyelia was associated in 28.4% of cases and hydrocephalus in 8%. According to findings at the intra-operative ultrasonography, a bony and ligamentous decompression alone was sufficient in 59.8% patients, a simple opening of dura mater was performed in 3% and a duraplasty in 27.1%. Seven patients experience post-operative complications, and 3 patients needed a second surgical operation for insufficient decompression, found at follow-up. Discussion and conclusion- The standard surgical treatment of CM-1/ CM-1.5 consists in decompression of posterior cranial fossa. Whether to perform a simple bony decompression or to associate the opening of the dura mater with duraplasty has always been controversial in pediatric population. Our case series, where good radiological findings were achieved with a limited number of reoperations, shows how intra-operative ultrasound may be a real-time helpful tool in orienting the surgical strategy, if we consider as surgical endpoint the restoration of cerebrospinal fluid (CSF) flux. However, there is the need to standardize this method, using quantitative variables.

Postoperative adhesive arachnoiditis is an inflammatory response of the spinal leptomeninges that occurs after surgery, resulting in scar formation in the avascular nature of the arachnoid layer. Clinical manifestations of this condition include pain, sensory deficits, motor dysfunction, reflex abnormalities, and bladder/bowel impairments. In MRI scans, the signs of postoperative adhesive arachnoiditis can vary, but some specific indicators can assist surgeons in locating the lesion and planning surgical interventions more accurately. In this report, we reported a 37-year-old man with postoperative adhesive arachnoiditis after two surgeries for Chiari I malformation, demonstrating that the gradually-forming the delta cord sign with sequential syringomyelia. During the intraoperative examination, we identified the presence of the delta cord sign, which was formed by an arachnoid scar that was tethering the dorsal spinal cord to the dura. This discovery allowed us to precisely pinpoint the location of the arachnoid scar, thereby providing valuable guidance to avoid any unnecessary exploration of innocent structures during the procedure. Other localization signs were also reviewed.

Chiari malformation type 1 (CM1) includes a series of congenital anomalies that share ectopia of the cerebellar tonsils below 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.

Syringomyelia can be associated with multiple etiologies. The treatment of the underlying causes is the first-line therapy, however, a direct approach to the syrinx is accepted as rescue treatment. Any direct intervention on the syrinx requires a myelotomy, posing a significant risk of iatrogenic spinal cord (SC) injury. Intraoperative neurophysiological monitoring (IONM) is crucial to detect and prevent surgically induced damage in neural SC pathways. We retrospectively reviewed the perioperative and intraoperative neurophysiological data and perioperative neurological examinations in ten cases of syringomyelia surgery. All monitored modalities remained stable throughout the surgery in six cases, correlating with no new postoperative neurological deficits. In two patients, significant transitory attenuation, or loss of motor evoked potentials (MEPs), were observed and recovered after a corrective surgical maneuver, with no new postoperative deficit. In two cases, a significant MEP decrement was noted, which lasted until the end of the surgery and was associated with postoperative weakness. A transitory train of neurotonic electromyography (EMG) discharges was reported in one case, the surgical plan was adjusted and the patient showed no postoperative deficit. The dorsal nerve roots were stimulated and identified in the seven cases where the myelotomy was performed via the dorsal root entry zone. Dorsal column mapping guided the myelotomy entry zone in four cases. In conclusion, multimodal IONM is feasible and reliable and may help prevent iatrogenic SC injury during syringomyelia surgery.