Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy—part 1: clinical setting and neurophysiological procedure

Introduction: Selective dorsal rhizotomy (SDR) consists of microsurgical partial deafferentation of sensory nerve roots (L1-S2). It is primarily used today in decreasing spasticity in young cerebral palsy (CP) patients. Intraoperative monitoring (IOM) is an essential part of the surgical decision-making process, aimed at improving functional results. The role played by SDR-IOM is examined, while realizing that connections between complex EMG responses to nerve-root stimulation and a patient's individual motor ability remain to be clarified. Methods: We conducted this retrospective study, analyzing EMG responses in 146 patients evoked by dorsal-root and rootlet stimulation, applying an objective response-classification system, and investigating the prevalence and distribution of the assessed grades. Part1 describes the clinical setting and SDR procedure, reintroduced in Germany by the senior author in 2007. Results: Stimulation-evoked EMG response patterns revealed significant differences along the segmental levels. More specifically, a comparison of grade 3+4 prevalence showed that higher-graded rootlets were more noticeable at lower nerve root levels (L5, S1), resulting in a typical rostro-caudal anatomical distribution. Conclusions: In view of its prophylactic potential, SDR should be carried out at an early stage in all CP patients suffering from severe spasticity. It is particularly effective when used as an integral part of a coordinated, comprehensive spasticity program in which a team of experts pool their information. The IOM findings pertaining to the anatomical grouping of grades could be of potential importance in adjusting the SDR-IOM intervention to suit the specific individual constellation, pending further validation. Trial registration: ClinicalTrials.gov ID: NCT03079362

Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy—part 2: gender differences and left-biased asymmetry

Introduction: Spinal reflexes reorganize in cerebral palsy (CP), producing hyperreflexia and spasticity. CP is more common among male infants, and gender might also influence brain and spinal-cord reorganization. This retrospective study investigated the frequency of higher-graded EMG responses elicited by electrical nerve-root stimulation during selective dorsal rhizotomy (SDR), prior to partial nerve- root deafferentation, considering not only segmental level and body side, but also gender. Methods: Intraoperative neuromonitoring (IOM) was used in SDR to pinpoint the rootlets most responsible for exacerbated stimulation-evoked EMG patterns recorded from lower-limb muscle groups. Responses were graded according to an objective response-classification system, ranging from no abnormalities (grade 0) to highly abnormal (grade 4+), based on ipsilateral spread and contralateral involvement. Non-parametric analysis of data with repeated measures was primarily used in investigating the frequency distribution of these various EMG response grades. Over 7000 rootlets were stimulated, and the results for 65 girls and 81 boys were evaluated, taking changes in the composition of patient groups into account when considering GMFCS levels. Results: The distribution of graded EMG responses varied according to gender, laterality, and level. Higher-graded EMG responses were markedly more frequent in the boys and at lower segmental levels (L5, S1). Left-biased asymmetry in higher-graded rootlets was also more noticeable in the boys and in patients with GMFCS level I. A close link was observed between higher-grade assessments and left-biased asymmetry. Conclusions: Detailed insight into the patient's initial spinal-neurofunctional state prior to deafferentation suggests that differences in asymmetrical spinal reorganization might be attributable to a hemispheric imbalance

Integrated understanding of hydrocephalus — a practical approach for a complex disease

Most of childhood hydrocephalus are originating during infancy. It is considered to be a complex disease since it is developed on the basis of heterogeneous pathophysiological mechanisms and different pathological conditions as well as during different age groups. Hence, it is of relevant importance to have a practical concept in mind, how to categorize hydrocephalus to surgically better approach this disease. The current review should offer further basis of discussion on a disease still most frequently seen in Pediatric Neurosurgery. Current literature on pathophysiology and classification of pediatric hydrocephalus has been reviewed to integrate the different published concepts of hydrocephalus for pediatric neurosurgeons. The current understanding of infant and childhood hydrocephalus pathophysiology is summarized. A simplified concept based on seven factors of CSF dynamics is elaborated and discussed in the context of recent discussions. The seven factors such as pulsatility, CSF production, major CSF pathways, minor CSF pathways, CSF absorption, venous outflow, and respiration may have different relevance and may also overlap for the individual hydrocephalic condition. The surgical options available for pediatric neurosurgeons to approach hydrocephalus must be adapted to the individual condition. The heterogeneity of hydrocephalus causes mostly developing during infancy warrant a simplified overview and understanding for an everyday approach. The proposed guide may be a basis for further discussion and may serve for a more or less simple categorization to better approach hydrocephalus as a pathophysiological complex disease

Introduction to the annual issue on “Infant Hydrocephalus“

We use a methodological framework exploiting the power of large ensembles to evaluate how well ten coupled climate models represent the internal variability and response to external forcings in observed historical surface temperatures. This evaluation framework allows us to directly attribute discrepancies between models and observations to biases in the simulated internal variability or forced response, without relying on assumptions to separate these signals in observations. The largest discrepancies result from the overestimated forced warming in some models during recent decades. In contrast, models do not systematically over- or underestimate internal variability in global mean temperature. On regional scales, all models misrepresent surface temperature variability over the Southern Ocean, while overestimating variability over land-surface areas, such as the Amazon and South Asia, and high-latitude oceans. Our evaluation shows that MPI-GE, followed by GFDL-ESM2M and CESM-LE offer the best global and regional representation of both the internal variability and forced response in observed historical temperatures

Single center experiences with telemetric intracranial pressure measurements in patients with CSF circulation disturbances

Background: Hydrocephalus may present with heterogeneous signs and symptoms. The indication for its treatment and the optimal drainage in complex cases may be challenging. Telemetric intracranial pressure measurements (TICPM) may open new perspectives for those circumstances. We report our experiences using the Neurovent-P-tel and the Sensor Reservoir in a retrospective study. Methods: A series of 21 patients (age range 10–39.5 years) treated in our Pediatric Neurosurgical Unit receiving a TICPM was analyzed. In 8 patients, a Neurovent-P-Tel was implanted; 13 patients received a Sensor Reservoir, 6 of which as a stand-alone implant, while 7 were already shunted. TICPM were performed on an outpatient basis. Possible complications, follow-up surgeries, and TICPM were analyzed. Results: Concerning the complications, one infection was seen in each group and one postoperative seizure was observed in the P-tel group. TICPM-assisted shunt adjustments lead to clinical improvements in six patients in the P-tel group and six patients in the Sensor Reservoir group. In four out of six non-shunted patients, TICPM contributed to the indication toward shunt implantation. Conclusions: TICPM seems to be a promising tool to improve clinical management of shunted patients with complex hydrocephalus. The two available systems will need further technical improvements, concerning implantation time, measurements, and data analysis in order to optimize handling and interpretation of the data

Neuroendoscopic surgery in neonates — indication and results over a 10-year practice

Purpose!#!Neuroendoscopic procedures for treatment of term and preterm newborn infants, such as endoscopic lavage for posthemorrhagic hydrocephalus, are gaining popularity despite sparse data. This single-institution report compiles all neuroendoscopic surgical procedures performed in neonates during a 10-year period.!##!Methods!#!Charts and electronic records were reviewed of all consecutive newborns who underwent a neuroendoscopic procedure before reaching a postmenstrual age of 44 weeks between 09/2010 and 09/2020. Available documentation was reviewed regarding the performed neuroendoscopic procedure, course of disease, complications, and all re-operations throughout the first year of life.!##!Results!#!During the 10-year study period, 116 infants (median gestational age at birth: 29 !##!Conclusion!#!The experience with this large cohort of neonates demonstrates the feasibility of neuroendoscopic technique for the treatment of posthemorrhagic or postinfectious hydrocephalus. Rate and type of complications after neuroendoscopic procedures were within the expected range. Assessing the potential long-term benefits of neuroendoscopic techniques has to await results of ongoing studies

Extended experience in parieto-occipital expansion surgery by meander technique—clinical and radiological evaluation

Introduction!#!Brachycephaly and anterior and posterior plagiocephaly appear as an isolated entity or manifest in syndromic conditions. In severe cases, possible treatment options currently comprise either cranioplasty or osteogenetic distraction. The aim of this paper is to retrospectively review the perioperative course of a series of children treated by posterior meander expansion technique at our institution with focus on the course of postoperative intracranial volume and eventual tonsillar descent evolution.!##!Methods!#!Forty-two children received a posterior cranial vault remodeling by means of a posterior meander technique during a 7-year period. Hospital records were reviewed, and pre- and postoperative MRIs were analyzed for intracranial volume, cephalic and asymmetry index, and tonsillar position over time.!##!Results!#!Median age at surgery was 11.5 months (range 17 days-10 years). Nineteen children had a symmetrical cranial deformity, twenty-three an asymmetrical synostosis. Half of the cohort showed a syndromic condition. Transfusions were administered in the majority (92.2%) of the cases. A significant postoperative increase of intracranial volume was present from 1188.9 ± 370.4 cm!##!Conclusion!#!Among the osteoplastic techniques, the posterior meander technique offers several advantages, such as early mobilization of the child, less bony defects, absence of implants, and a small complication rate. However, further comparative studies among different surgical techniques are needed

Biparietal meander expansion technique for sagittal suture synostosis in patients older than 1 year of age—technical note

Objective!#!Sagittal suture synostosis (SSS) is the most common form of craniosynostosis. For older patients, the strategy for surgical correction needs to consider diminished growth dynamics of the skull and an active reconstruction cranioplasty aims to sustain stability for the active child. We describe our technique of biparietal meander expansion (BME) technique for SSS for patients older than 1 year and retrospectively reviewed the perioperative course as well as the subjective experience of patients and caregivers during follow-up.!##!Methods!#!The BME technique incorporates bilateral serpentine craniotomies and fixation of the consecutively expanded bone tongues with crossing sutures for patients with SSS older than 12 months of age at surgery. We reviewed patients undergoing this surgical technique for correction of SSS and collected data about the clinical course and performed a patients reported outcome measure (PROM) for patients or caregivers to evaluate subjective experience and outcome after surgical treatment.!##!Results!#!BME was performed in 31 patients (8 females; median age: 43 months; range 13-388). The mean length of operation was 172.7±43 minutes (range 115-294). Patients experienced no immediate complications or neurological morbidity after surgery. Considering a total of 21 completed PROM questionnaires, the head shape after surgery was evaluated as either 'better' (57%) or 'much better' (43%) compared to preoperatively. Eighty-one percent of patients or caregivers answered that the patient experiences no limitation in daily activities. Although 42.8% perceived the hospital as strenuous, 90.5% would choose to undergo this treatment again.!##!Conclusion!#!BME is a feasible technique for older SSS patients resulting in immediate stability of the remodelled calvarium with a more normal head shape. The survey among caregivers or patients revealed a favourable subjectively experienced outcome after this type of surgical treatment of SSS in the more complex context of an older patient cohort

Heterogeneous regional and temporal energetic impairment following controlled cortical impact injury in rats

OBJECTIVES: Following traumatic brain injury metabolic stability is impaired. Duration and reversibility of these changes might be important to guide specific interventions. METHODS: To characterize temporal and regional changes in cerebral metabolism, 68 male Sprague-Dawley rats were subjected to a focal cortical contusion. Lesion progression and mitochondrial impairment were determined by magnetic resonance imaging (MRI) and triphenyl tetrazolium chloride (TTC) staining, respectively. Metabolic alterations were determined at hours 6 and 24 and day 7 by measuring extracellular glucose, lactate and hypoxanthine levels with microdialysis catheters placed adjacent and distant to the contusion and by quantifying changes in tissue ATP, lactate and glucose using bioluminescence imaging. RESULTS: The cortical lesion reached its maximal extent at hour 24 and remained confined to the ipsilateral hemisphere. In microdialysate, at hour 6, extracellular hypoxanthine and lactate reached maximal values, thereafter hypoxanthine normalized while lactate remained increased. Extracellular glucose reached the highest values at hour 24 and remained elevated. Bioluminescence imaging revealed heterogeneous changes in areas distant to the contusion. No significant changes were found in ATP content. Slightly elevated tissue glucose until 24 hours in the ipsilateral hemisphere was observed. Following a continuous increase, lactate levels were the highest by 6 hours in the ipsilateral cortex and hippocampus. DISCUSSION: CCI is associated with disturbances in energetic metabolism. Metabolic perturbation is not restricted to the early phase and the contusional region following focal cortical contusion, but also involves hippocampus and primarily uninjured parts of the hemisphere

First experience with augmented reality neuronavigation in endoscopic assisted midline skull base pathologies in children

Introduction!#!Endoscopic skull base approaches are broadly used in modern neurosurgery. The support of neuronavigation can help to effectively target the lesion avoiding complications. In children, endoscopic-assisted skull base surgery in combination with navigation systems becomes even more important because of the morphological variability and rare diseases affecting the sellar and parasellar regions. This paper aims to analyze our first experience on augmented reality navigation in endoscopic skull base surgery in a pediatric case series.!##!Patients and methods!#!A retrospective review identified seventeen endoscopic-assisted endonasal or transoral procedures performed in an interdisciplinary setting in a period between October 2011 and May 2020. In all the cases, the surgical target was a lesion in the sellar or parasellar region. Clinical conditions, MRI appearance, intraoperative conditions, postoperative MRI, possible complications, and outcomes were analyzed.!##!Results!#!The mean age of our patients was 14.5 ± 2.4 years. The diagnosis varied, but craniopharyngiomas (31.2%) were mostly represented. AR navigation was experienced to be very helpful for effectively targeting the lesion and defining the intraoperative extension of the pathology. In 65% of the oncologic cases, a radical removal was proven in postoperative MRI. The mean follow-up was 89 ± 79 months. There were no deaths in our series. No long-term complications were registered; two cerebrospinal fluid (CSF) fistulas and a secondary abscess required further surgery.!##!Conclusion!#!The implementation of augmented reality to endoscopic-assisted neuronavigated procedures within the skull base was feasible and did provide relevant information directly in the endoscopic field of view and was experienced to be useful in the pediatric cases, where anatomical variability and rarity of the pathologies make surgery more challenging