Caudal Agenesis: Classification Based on the Pathoembryogenesis of the Spinal Cord.

BACKGROUND AND OBJECTIVES: Caudal agenesis (CA) is a congenital disease characterized by lower vertebral bone defects. Previous classifications for CA were based on the levels of bony defects or the conus medullaris. We created a new pathoembryogenic classification that takes into account the level of conus, considering both its shape and filum. We evaluated its accuracy in reflecting the neurological status and the need for untethering. METHODS: Patients with radiologic studies available on our institute's electronic image view system between 1985 and 2019 were reviewed. Our classification categorized patients with CA into 3 groups: the failure of formation (a conus level > L1 or normal level conus with a blunt shape), the failure of regression (a conus level < L3 or normal level conus with a thickened filum or a filar lipoma), and the normal (a normal level conus without specific abnormalities). We analyzed which of the following 3 classifications better reflects the neurological status and the probability of recommending untethering: classifications based on (1) bony defect level, (2) conus level, and (3) pathoembryogenic mechanism. RESULTS: A total of 89 patients were included in this study. The pathoembryogenic classification revealed more significant differences in motor or sensory deficits compared with other classifications (failure of formation: 42%; failure of regression: 16%; and normal: 0%, P = .039). In addition, the pathoembryogenic classification emerged as a significant or suggestive predictive factor for motor and sensory deficits (motor: odds ratio 11.66, P = .007; sensory: odds ratio 5.44, P = .066). Notably, only the pathoembryogenic classification exhibited a significant difference in the probabilities of recommending untethering between groups (failure of formation: 42%; failure of regression: 81%; and normal 12%, P < .001). CONCLUSION: The correlation between bony classification and spinal cord abnormalities was exaggerated. Our new pathoembryogenic classification was valuable in prognosticating neurological status and identifying the patient group more likely to require untethering among patients with CA.

The Outcomes of Endoscopic Suturectomy in Syndromic Craniosynostosis.

OBJECTIVE: Endoscopic suturectomy is a widely practiced surgical option for infants with craniosynostosis. But the efficacy and safety of the procedure remain unclear in syndromic patients. This study aims to evaluate the efficacy and safety of endoscopic suturectomy for patients with syndromic craniosynostosis. METHODS: From January 2013 to December 2020, 242 patients underwent endoscopic suturectomy at our institution. The surgical outcome was determined to be favorable or unfavorable based upon the necessity of an additional cranial surgery upon the last follow-up. First, we analyzed the outcomes of 26 syndromic craniosynostosis patients who have followed up for over a year. Second, we compared the outcomes between the syndromic (N=12) and nonsyndromic (N=11) patients with bilateral coronal synostosis who have followed up for over a year. RESULTS: Twenty-three out of 26 syndromic craniosynostosis patients (88%) showed favorable outcomes without significant complications. In the analysis for bilateral coronal synostosis patients, 11 of 12 syndromic patients (92%) presented favorable outcomes, and all nonsyndromic patients showed favorable outcomes. No significant differences were observed in various anthropometric indices (cranial index, intracranial volume, anterior cranial height, anterior cranial base length, and cranial height-length index) and surgical outcomes between syndromic and nonsyndromic groups. CONCLUSIONS: Endoscopic suturectomy has the potential to be a surgical option for syndromic craniosynostosis. Even for patients with unfavorable outcomes, endoscopic suturectomy could serve as a bridge treatment for infants to counter cranial deformation before additional extensive surgery.

Growth patterns of young achondroplasia patients in Korea and predictability of neurosurgical procedures.

BACKGROUND: Achondroplasia is an autosomal dominant disorder mainly affecting bony growth, typically resulting in markedly short stature. From a neurosurgical viewpoint, patients sometimes develop spinal cord compression at the narrowed foramen magnum and hydrocephalus. This study aims to construct growth references for height, weight, and head circumference (HC) of young achondroplasia patients in Korea and to evaluate the predictability of the necessity and timing of neurosurgical procedures through growth patterns. METHODS: Growth data were collected from achondroplasia patients who visited our institution between January 2002 and August 2022. First, we constructed percentile growth curves of height, weight, and HC for the patients under 3 years of age with the generalized additive model for location, scale, and shape (GAMLSS). Second, the growth patterns of the patients with hydrocephalus who underwent neurosurgical procedures such as foramen magnum decompression (FMD) and ventriculoperitoneal (VP) shunt were analyzed. RESULTS: There were 125 achondroplasia patients, including 67 males and 58 females. Among 125 patients, 46 underwent FMD, and 5 underwent VP shunt. As short stature and macrocephaly were typical characteristics of achondroplasia, the height of achondroplasia was lower than that of the general population, and HC in achondroplasia showed accelerated growth postnatally. There were no significant changes in HC in hydrocephalus patients before they underwent neurosurgical procedures. The influence of hydrocephalus on the growth patterns of HC in achondroplasia seemed insignificant. CONCLUSION: Growth references for height, weight, and HC in young achondroplasia patients were constructed. It is the first report of growth patterns of achondroplasia in Korea. Unlike other pediatric patients, the diagnosis of hydrocephalus and the necessity of neurosurgical procedures are hard to be predicted with HC in achondroplasia. Neuroimaging should be considered for achondroplasia patients with neurological symptoms.

Clinical outcomes of pediatric cerebral cavernous malformation: an analysis of 124 consecutive cases.

OBJECTIVE: One-fourth of cerebral cavernous malformation (CCM) patients are children, but studies on these patients are scarce. This study aimed to identify the clinical presentation of pediatric CCM patients and to investigate clinical outcomes according to the treatment modalities applied on the basis of our institution's treatment strategy. METHODS: The authors performed a retrospective analysis of 124 pediatric CCM patients with a follow-up of more than 1 year from 2000 to 2019. They performed resection (n = 62) on lesions causing intractable seizure, rebleeding, or mass effect and observed the clinical courses of patients with lesions in deep or eloquent areas without persistent symptoms (n = 52). Radiosurgery (n = 10) was performed when the patient refused resection or strongly desired radiosurgery. The authors investigated the clinical characteristics, performance status (modified Rankin Scale [mRS] score), and rebleeding rate at the 1-year and last follow-up examinations and compared these among 3 groups classified on the basis of treatment applied. The authors evaluated seizure outcomes at the 1-year and last follow-up examinations for the surgery (n = 32) and observation (n = 17) groups. Finally, the authors drew cumulative incidence curves for the discontinuation of antiepileptic drugs (AEDs) for patients in the surgery (n = 30) and observation (n = 9) groups. RESULTS: The 3 groups showed slight differences in initial symptoms, lesion locations, and rates of recent hemorrhage. The proportion of patients with improved mRS score at the 1-year follow-up was significantly greater in the surgery group than in the other groups (67% of the surgery group, 52% observation group, and 40% radiosurgery group; p = 0.078), as well as at the last follow-up (73% surgery group, 54% observation group, and 60% radiosurgery group; p = 0.097). The surgery group also had the lowest rebleeding rate during the follow-up period (2% surgery group, 11% observation group, and 20% radiosurgery group; p = 0.021). At the 1-year follow-up, the proportion of seizure-free patients without AEDs was significantly higher in the surgery group than the observation group (88% surgery group vs 53% observation group, p < 0.001), and similar results were obtained at the last follow-up (91% surgery group vs 56% observation group, p = 0.05). The 5-year AED-free rates for the surgery and observation groups were 94% and 50%, respectively, on the cumulative incidence curve (p = 0.049). CONCLUSIONS: The clinical presentation of pediatric CCM patients was not significantly different from that of adult patients. Lesionectomy may be acceptable for pediatric CCM patients with indications of persistent seizures despite AED medications, rebleeding, and mass effects.

Myelomeningocele as an anomaly of secondary neurulation.

PURPOSE: Myelomeningocele (MMC) is the representative entity of open neural tube defects resulting from an error during primary neurulation. However, cases of MMC in the region of the secondary neural tube (below the junction of S1 and S2 vertebrae) are sometimes encountered. We aimed to analyze the clinical features of atypical "low-lying" MMC in comparison to the typical MMC and suggest possible pathoembryogenesis. METHODS: From 1986 to 2020, 95 MMC patients were treated in our institute. A retrospective review of the radiological and clinical information was performed. We defined "low-lying" MMCs as those with fascia or lamina defects below the S1-2 interspinous ligament. RESULTS: Thirty-one out of the 95 MMC patients were identified as having low-lying MMC. The percentage of low-lying MMC within the entire MMC group increased dramatically (19% from 1990 to 1999 and 48% from 2000 to 2020). Thirty-nine percent of the low-lying MMCs were associated with hydrocephalus, and 36% showed the Chiari malformation. Clean intermittent catheterization was being performed by 52% of the patients and 46% had a motor weakness. The proportions of hydrocephalus, neurological symptoms, and the number of related procedures in the low-lying MMC were substantially lower than the typical MMC in our cohort and the literature. CONCLUSIONS: We present cases of atypical MMC occurring in the region of secondary neurulation. These cases provide clues that secondary neurulation may lead to open neural defects. Future experiments with animal models supporting what we have seen in the clinics will greatly enhance the understanding of the developmental process of neurulation and the corresponding anomalies.

Real-Time Evaluation of Cerebral Autoregulation Based on Near-Infrared Spectroscopy to Predict Clinical Outcome after Bypass Surgery in Moyamoya Disease.

Impaired cerebral autoregulation (CA) can cause negative outcomes in neurological conditions. Real-time CA monitoring can predict and thereby help prevent postoperative complications for neurosurgery patients, especially those suffering from moyamoya disease (MMD). We applied the concept of moving average to the correlation between mean arterial blood pressure (MBP) and cerebral oxygen saturation (SCO2) to monitor CA in real time, revealing optimal window size for the moving average. The experiment was conducted with 68 surgical vital-sign records containing MBP and SCO2. To evaluate CA, the cerebral oximetry index (COx) and coherence obtained from transfer function analysis (TFA) were calculated and compared between patients with postoperative infarction and those who without. For real-time monitoring, the moving average was applied to COx and coherence to determine the differences between groups, and the optimal moving-average window size was identified. The average COx and coherence within the very-low-frequency (VLF) range (0.02-0.07 Hz) during the entire surgery were significantly different between the groups (COx: AUROC = 0.78, p = 0.003; coherence: AUROC = 0.69, p = 0.029). For the case of real-time monitoring, COx showed a reasonable performance (AUROC > 0.74) with moving-average window sizes larger than 30 minutes. Coherence showed an AUROC > 0.7 for time windows of up to 60 minutes; however, for windows larger than this threshold, the performance became unstable. With an appropriate window size, COx showed stable performance as a predictor of postoperative infarction in MMD patients.

Retained medullary cord and terminal myelocystocele as a spectrum: case report.

The caudal portion of the spinal cord, the medullary cord, is formed by secondary neurulation. One of the distinctive features of secondary neurulation compared to primary neurulation is that the medullary cord normally degenerates into a filum in humans. Various anomalies have been known to originate from degenerating process errors. One anomaly is terminal myelocystocele (TMCC), which is a closed spinal dysraphism with an elongated caudal spinal cord. The terminal part is filled with cerebrospinal fluid (CSF) and protrudes into the dorsal extradural space. Another anomaly is the retained medullary cord (RMC), which is a nonfunctioning cord-like structure extending to the cul-de-sac. In a 1-month-old boy, we identified an RMC with cystic dilatation of the caudal end extending to the epidural space at the very bottom of the cul-de-sac, resembling a degenerating terminal balloon, which is an essential feature of TMCC. Hence, this case may be considered an intermediate form between TMCC and RMC. This case provides clinical evidence that TMCC and RMC share the same pathoembryogenic origin, namely, failure of the regression phase of secondary neurulation.

Cerebrospinal Fluid Profiles and Their Changes after Intraventricular Chemotherapy as Prognostic or Predictive Markers for Patients with Leptomeningeal Carcinomatosis.

OBJECTIVE: Here, we evaluated whether cerebrospinal fluid (CSF) profiles and their changes after intraventricular chemotherapy for leptomeningeal carcinomatosis (LMC) could predict the treatment response or be prognostic for patient overall survival (OS) along with clinical factors. METHODS: Paired 1) pretreatment lumbar, 2) pretreatment ventricular, and 3) posttreatment ventricular samples and their CSF profiles were collected retrospectively from 148 LMC patients who received Ommaya reservoir installation and intraventricular chemotherapy. CSF profile changes were assessed by calculating the differences between posttreatment and pretreatment samples from the same ventricular compartment. CSF cell counts were further differentiated into total and other based on clinical laboratory reports. RESULTS: For the treatment response, a decreased CSF 'total' cell count tended to be associated with a 'controlled' increase in intracranial pressure (ICP) (p=0.059), but other profile changes were not associated with either the control of increased ICP or the cytology response. Among the pretreatment CSF profiles, lumbar protein level and ventricular cell count were significantly correlated with OS in univariable analysis, but they were not significant in multi-variable analysis. Among CSF profile changes, a decrease in 'other' cell count showed worse OS than 'no change' or increased groups (p=0.001). The cytological response was significant for OS, but the hazard ratio of partial remission was paradoxically higher than that of 'no response'. CONCLUSION: A decrease in other cell count of CSF after intraventricular chemotherapy was associated with poor OS in LMC patients. We suggest that more specific CSF biomarkers of cancer cell origin are needed.

Predictors of cervical myelopathy and hydrocephalus in young children with achondroplasia.

BACKGROUND: Cervical myelopathy and hydrocephalus occasionally occur in young children with achondroplasia. However, these conditions are not evaluated in a timely manner in many cases. The current study presents significant predictors for cervical myelopathy and hydrocephalus in young children with achondroplasia. METHODS: A retrospective analysis of 65 patients with achondroplasia who visited Seoul National University Children's Hospital since 2012 was performed. The patients were divided into groups according to the presence of cervical myelopathy and hydrocephalus, and differences in foramen magnum parameters and ventricular parameters by magnetic resonance imaging between groups were analyzed. Predictors for cervical myelopathy and hydrocephalus were analyzed, and the cut-off points for significant ones were calculated. RESULTS: The group with cervical myelopathy showed foramen magnum parameters that indicated significantly lower cord thickness than in the group without cervical myelopathy, and the group with hydrocephalus showed significantly higher ventricular parameters and 'Posterior indentation' grade than the group without hydrocephalus. 'Cord constriction ratio' (OR 5199.90, p = 0.001) for cervical myelopathy and 'Frontal horn width' (OR 1.14, p = 0.001) and 'Posterior indentation' grade (grade 1: OR 9.25, p = 0.06; grade 2: OR 18.50, p = 0.01) for hydrocephalus were significant predictors. The cut-off points for cervical myelopathy were 'Cord constriction ratio' of 0.25 and 'FM AP' of 8 mm (AUC 0.821 and 0.862, respectively) and 'Frontal horn width' of 50 mm and 'Posterior indentation' grade of 0 (AUC 0.788 and 0.758, respectively) for hydrocephalus. CONCLUSION: 'Cord constriction ratio' for cervical myelopathy and 'Frontal horn width' and 'Posterior indentation' grade for hydrocephalus were significant predictors and may be used as useful parameters for management. 'Posterior indentation' grade may also be used to determine the treatment method for hydrocephalus.

Failed First Craniotomy and Tumor Removal of Parasagittal Meningioma with Severe Peritumoral Brain Edema.

Parasagittal meningioma often presents as peritumoral brain edema (PTBE). The risk of edema increases when the tumor occludes the superior sagittal sinus (SSS). Although PTBE may be expected based on the patient's symptoms or radiologic findings, extensive brain swelling and extracranial herniation during elective surgery are rare. Herniation during surgery could lead to irreversible neurological damage and even brain rupture. We report a case of a failed routine craniotomy for a parasagittal meningioma with complete occlusion of the posterior third of the SSS in a 30-year-old male patient. The patient developed extensive brain swelling and extracranial herniation during surgery.

Retrospective Analysis of Cerebrospinal Fluid Profiles in 228 Patients with Leptomeningeal Carcinomatosis : Differences According to the Sampling Site, Symptoms, and Systemic Factors.

OBJECTIVE: Elevated cell counts and protein levels in cerebrospinal fluid (CSF) result from disease activity in patients with leptomeningeal carcinomatosis (LMC). Previous studies evaluated the use of CSF profiles to monitor a treatment response or predict prognosis. CSF profiles vary, however, according to the sampling site and the patient's systemic condition. We compared lumbar and ventricular CSF profiles collected before intraventricular chemotherapy for LMC and evaluated the association of these profiles with patients' systemic factors and LMC disease activity. METHODS: CSF profiles were retrospectively collected from 228 patients who underwent Ommaya reservoir insertion for intraventricular chemotherapy after a diagnosis of LMC. Lumbar samples taken via lumbar puncture were used for the diagnosis, and ventricular samples were obtained later at the time of Ommaya reservoir insertion. LMC disease activity was defined as the presence of LMC-related symptoms such as increased intracranial pressure, hydrocephalus, cranial neuropathy, and cauda equina syndrome. RESULTS: Cell counts (median : 8 vs. 1 cells/mL) and protein levels (median : 68 vs. 17 mg/dL) significantly higher in lumbar CSF than in ventricular CSF (p<0.001). Among the evaluated systemic factors, concomitant brain metastasis and previous radiation were significantly correlated with higher protein levels in the lumbar CSF (p=0.01 and <0.001, respectively). Among the LMC disease activity, patients presenting with hydrocephalus or cauda equina syndrome showed higher lumbar CSF protein level compared with that in patients without those symptoms (p=0.049 and p<0.001, respectively). The lumbar CSF cell count was significantly lower in patients with cranial neuropathy (p=0.046). The ventricular CSF cell counts and protein levels showed no correlation with LMC symptoms. Carcinoembryonic antigen (CEA), which was measured from ventricular CSF after the diagnosis in 109 patients, showed a significant association with the presence of hydrocephalus (p=0.01). CONCLUSION: The protein level in lumbar CSF indicated the localized disease activity of hydrocephalus and cauda equina syndrome. In the ventricular CSF, only the CEA level reflected the presence of hydrocephalus. We suggest using more specific biomarkers for the evaluation of ventricular CSF to monitor disease activity and treatment response.