Two novel tumours with NTRK2 fusion in the methylation class of extraventricular neurocytomas, including one intraventricular.

We report here about two novel tumours classified as extraventricular neurocytomas (EVN) using DNA-methylation profiling, associated with NTRK2 fusions instead of the usual FGFR1 alterations so far attributed to this tumoural entity. We present the second detailed case of an intraventricular presentation in the MC EVN. Our findings broaden the spectrum of MC EVN and have implications in terms of diagnosis, therapy and terminology.

A new subtype of diffuse midline glioma, H3 K27 and BRAF/FGFR1 co-altered: a clinico-radiological and histomolecular characterisation.

Diffuse midline gliomas (DMG) H3 K27-altered are incurable grade 4 gliomas and represent a major challenge in neuro-oncology. This tumour type is now classified in four subtypes by the 2021 edition of the WHO Classification of the Central Nervous System (CNS) tumours. However, the H3.3-K27M subgroup still appears clinically and molecularly heterogeneous. Recent publications reported that rare patients presenting a co-occurrence of H3.3K27M with BRAF or FGFR1 alterations tended to have a better prognosis. To better study the role of these co-driver alterations, we assembled a large paediatric and adult cohort of 29 tumours H3K27-altered with co-occurring activating mutation in BRAF or FGFR1 as well as 31 previous cases from the literature. We performed a comprehensive histological, radiological, genomic, transcriptomic and DNA methylation analysis. Interestingly, unsupervised t-distributed Stochastic Neighbour Embedding (tSNE) analysis of DNA methylation profiles regrouped BRAFV600E and all but one FGFR1MUT DMG in a unique methylation cluster, distinct from the other DMG subgroups and also from ganglioglioma (GG) or high-grade astrocytoma with piloid features (HGAP). This new DMG subtype harbours atypical radiological and histopathological profiles with calcification and/or a solid tumour component both for BRAFV600E and FGFR1MUT cases. The analyses of a H3.3-K27M BRAFV600E tumour at diagnosis and corresponding in vitro cellular model showed that mutation in H3-3A was the first event in the oncogenesis. Contrary to other DMG, these tumours occur more frequently in the thalamus (70% for BRAFV600E and 58% for FGFR1MUT) and patients have a longer overall survival with a median above three years. In conclusion, DMG, H3 K27 and BRAF/FGFR1 co-altered represent a new subtype of DMG with distinct genotype/phenotype characteristics, which deserve further attention with respect to trial interpretation and patient management.

Neurocognitive and radiological follow-up of children under 5 years of age treated for medulloblastoma according to the HIT-SKK protocol.

BACKGROUND: The HIT-SKK protocol is used for low/standard-risk medulloblastomas in young children with the aim to eliminate cranial irradiation and its neuropsychological (NP) sequelae. This therapy includes IV and intraventricular (ITV) methotrexate (MTX) potentially responsible for leukoencephalopathy (LE) and neurocognitive disorders. This study describes the risk factors and course of LE, and investigates its correlation with neurocognitive impact. METHODS: A retrospective, multicenter study was conducted in 35 children under 5 years old, with a median follow-up of 72 months (range 14 to 130). The main analysis was performed in 30 patients who received cumulative doses of MTX as per-protocol (group 1). Five patients who received higher cumulative doses of MTX were analyzed separately. All follow-up MRIs and NP assessments were centrally reviewed by experts. RESULTS: Twenty patients in group 1 developed LE, grade 2 and 3 abnormalities did not correlate with higher cumulative doses of ITV-MTX (p = 0.698). Considering the most recent NP evaluation, the Full-Scale IQ (FSIQ) and Wechsler indices were in the average to lower average range. The FSIQ was deficient in 6/17 evaluable patients. Cumulative dose of ITV-MTX was almost associated with decreased processing speed competence (p = 0.055) which was the most frequently impaired neurocognitive domain. Neuropsychological assessment scores were not statistically lower in patients with persistent grade 2 LE at the end of follow-up. CONCLUSION: This study described that the use of cumulative dose of MTX (IV and ITV) according to the HIT-SKK protocol resulted in LE that tented to decrease over time, without significant correlation with a decline in neuro-intellectual skills.

Does the participation of a senior plastic surgeon improve conditions of hospitalisation in craniosynostosis repair surgery?

INTRODUCTION: The real impact of the participation of other surgical specialties together with neurosurgeons on perioperative care in craniosynostosis repair surgery has not been determined. The purpose of this study was to determine whether the participation of a second senior surgeon (plastic surgeon) during surgical repair of pediatric monosutural craniosynostosis improved perioperative medical care. MATERIAL AND METHODS: The authors retrospectively reviewed 2 cohorts of patients who had consecutively undergone primary repair surgery for trigonocephaly and unicoronal craniosynostosis. Infants were operated on by a single senior pediatric neurosurgeon before December 2017, and with the collaboration of a senior plastic surgeon after January 2018. RESULTS: Overall, 60 infants were included in the study: 29 in group 1 (single surgeon, 2011-2017), and 31 in group 2 (pair of surgeons, 2018-2021). Median surgery time was significantly shorter in group 2 than group 1: 180 vs. 167minutes; P=0.0045. There was no significant difference between the 2 groups in blood loss or intra/postoperative packed erythrocyte transfusion. Postoperative drain output was significantly lower in group 2. Median length of hospital and intensive care stay were significantly shorter in group 2, by 1 and 2 days, respectively; P<0.0001. Volume of infused solution, diuresis, immediate postoperative hemoglobin level, hematocrit, hemostasis (platelet count, fibrinogen, prothrombin time and activated partial thromboplastin time), and return to oral feeding did not differ from one group to the other. CONCLUSION: Results confirmed our impression of an improvement in perioperative medical care. However, the role of surgical experience and the influence of the medical/nursing staff must not be minimized in these complex surgical procedures.

Prevalence and risk factors for scoliosis in adults with closed and open spina bifida: A large, cross-sectional study.

BACKGROUND: Scoliosis develops in a proportion of children with myelomeningocele; however, little is known about scoliosis in adulthood and in other forms of spina bifida (SB). OBJECTIVES: The aims of this study were to describe the prevalence of scoliosis and identify risk factors for its development in a large cohort of adults with open and closed SB. METHODS: This was a cross-sectional study of data from 580 adults with SB attending their first consultation at a French multidisciplinary referral centre for SB. Sex, anatomical location and type of SB (open or closed), neurological level, back pain and ambulatory status (new Functional Ambulation Classification [new FAC]) were compared in adults with and without scoliosis. These characteristics were used to determine scoliosis risk factors. RESULTS: In total, 331 adults fulfilled the inclusion criteria: 221 had open and 110 had closed SB. Of these, 176 (53%) had scoliosis: 57% open and 45% closed SB. As compared with individuals without scoliosis, those with scoliosis more frequently had open SB (p=0.03), more cranially located SB (p<0.0001), more severe neurological deficits (p≤0.02) and poorer walking ability (mean new FAC score 3.5 [SD 3.3] vs 6.1 [2.6], [p<0.0001]). In total, 69% had chronic back pain, with no difference in frequency between those with and without scoliosis. The odds of scoliosis was associated with asymmetrical motor level and a new FAC score <4 (odds ratio 0.46, p<0.006, and 0.75, p<0.0001, respectively). CONCLUSION: About half of adults with open and closed SB had scoliosis. Back pain was frequent in those both with and without scoliosis. Individuals with low walking ability and an asymmetrical motor level should be monitored early and continuously to limit the consequences of scoliosis during their lifetime. A major issue is to determine how scoliosis evolves and to determine appropriate monitoring and treatment strategies for individuals at risk.

Chiari malformation type I surgery in children: French multicenter 10-year cohort.

OBJECTIVE: Chiari malformation type I (CM-I) is frequent in children and remains a surgical challenge. Several techniques have been described for posterior fossa decompression. No decision algorithm has been validated, and strategies are highly variable between institutions. The goal of this study was to define therapeutic guidelines that take into consideration patient specificities. METHODS: The authors retrospectively collected data from patients who were < 18 years of age, were diagnosed with CM-I, and were treated surgically between 2008 and 2018 in 8 French pediatric neurosurgical centers. Data on clinical features, morphological parameters, and surgical techniques were collected. Clinical outcomes at 3 and 12 months after surgery were assessed by the Chicago Chiari Outcome Scale. The authors used a hierarchical clustering method to define clusters of patients by considering their anatomical similarities, and then compared outcomes between surgical strategies in each of these clusters. RESULTS: Data from 255 patients were collected. The mean age at surgery was 9.6 ± 5.0 years, syringomyelia was reported in 60.2% of patients, the dura mater was opened in 65.0% of patients, and 17.3% of patients underwent a redo surgery for additional treatment. The mean Chicago Chiari Outcome Scale score was 14.4 ± 1.5 at 3 months (n = 211) and 14.6 ± 1.9 at 12 months (n = 157). The hierarchical clustering method identified three subgroups with potentially distinct mechanisms underlying tonsillar herniation: bony compression, basilar invagination, and foramen magnum obstruction. Each cluster matched with specific outcomes. CONCLUSIONS: This French multicenter retrospective cohort study enabled the identification of three subgroups among pediatric patients who underwent surgery for CM-I, each of which was associated with specific outcomes. This morphological classification of patients might help in understanding the underlying mechanisms and providing personalized treatment.

Importance of tranexamic acid in pediatric monosutural craniosynostosis surgery.

OBJECTIVE: Tranexamic acid (TXA) is an antifibrinolytic drug that has achieved significant reduction in perioperative blood loss and the quantity of blood transfused in many pediatric surgical procedures, without morbidity. Despite the accumulation of evidence regarding its effectiveness in craniosynostosis repair surgery, TXA is not unanimously employed by pediatric neurosurgery teams. The purpose of this study was to evaluate the impact of the routine use of TXA in a homogeneous population of children who underwent open surgery for monosutural craniosynostosis. METHODS: The authors retrospectively reviewed 3 cohorts of patients that were subdivided from 2 cohorts surrounding the initiation of TXA (group 1, TXA- [2008-2011] and group 2, TXA+ [2011-2013]) and a third cohort of more recent patients (group 3, TXA+ [2016-2017]). TXA was administered using the same protocol comprising a loading dose of 10 mg/kg over 15 minutes after induction of general anesthesia followed by a 10 mg/kg per hour infusion until skin closure. Patients in all 3 groups underwent similar standardized procedures for scaphocephaly, trigonocephaly, and unicoronal craniosynostosis by the same pediatric neurosurgeon. RESULTS: Overall, 102 infants were included in the study: 32 infants in group 1, 36 in group 2, and 34 in group 3. Significant reductions in transfusion of packed erythrocytes (PE) and fresh-frozen plasma (FFP) were observed between the TXA- and TXA+ time periods. The median volume of PE transfusion was reduced by > 50% with the use of TXA (42.8 mL/kg in the TXA- group vs 20.0 in the TXA+ groups, p < 0.0001). Reduction in PE transfusion was 100% postoperatively in the TXA+ groups (20.0 mL/kg in the TXA- group vs 0.0 in the TXA+ groups, p < 0.0001). The median volume of FFP transfusion was reduced by 100% with the use of TXA (12.8 mL/kg in the TXA- group vs 0.0 in the TXA+ groups, p < 0.0001). All children in group 1 received a transfusion, whereas 3 children (8%) and 7 children (20%) in groups 2 and 3, respectively, did not. Significant reductions in postoperative drain output were also noted between the TXA- and TXA+ time periods. The total hospital length of stay was significantly lower in the TXA+ groups (p < 0.0001). CONCLUSIONS: Use of TXA reduced blood loss and the need for transfusions but also decreased the hospital length of stay and, thus, minimized overall medical care costs. Intraoperative administration of TXA in craniosynostosis repair surgery should be routinely used in all centers that practice these procedures.

Low-grade epilepsy-associated neuroepithelial tumours with a prominent oligodendroglioma-like component: The diagnostic challenges.

AIMS: We searched for recurrent pathological features and molecular alterations in a retrospective series of 72 low-grade epilepsy-associated neuroepithelial tumours (LEATs) with a prominent oligodendroglioma-like component, in order to classify them according to the 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumours. METHODS: Centralised pathological examination was performed as well as targeted molecular analysis of v-Raf murine sarcoma viral oncogene homologue B (BRAF) and fibroblast growth factor receptor 1 (FGFR1) by multiplexed digital polymerase chain reaction (mdPCR). DNA methylation profiling was performed in cases with sufficient DNA. In cases with no genetic alteration by mdPCR and sufficient material, RNA sequencing was done. RESULTS: We first reclassified our cohort into three groups: ganglioglioma (GG, n = 14), dysembryoplastic neuroepithelial tumours (DNTs, n = 19) and glioneuronal tumours/paediatric-type low-grade glioma (LGG) not otherwise specified (GNT/PLGG NOS, n = 39). mdPCR found an alteration in 38/72 cases. Subsequent RNA sequencing revealed a fusion transcript involving BRAF, FGFR1/2/3 or neurotrophic tyrosine kinase receptor type 2 [NTRK2] in 9/25 cases. DNA methylation profiling found 12/46 cases with a calibrated score ≥0.9. Unsupervised hierarchical clustering revealed two clusters: Cluster 1 was enriched with cases classified as DNT at histology, belonging to the LGG-DNT methylation class (MC), with haematopoietic progenitor cell antigen (CD34) negativity and FGRF1 alterations; Cluster 2 was enriched with cases classified at histology as GG, belonging to the LGG-GG MC MC, with BRAF V600E mutation and CD34 positivity. The tumours reclassified as GNT/PLGG NOS were equally distributed across both clusters. Interestingly, all polymorphous low-grade neuroepithelial tumour of the young belonged to Cluster 2, whereas diffuse LGG mitogen-activated protein kinase (MAPK) pathway-altered were equally distributed among the two clusters. This led us to build an algorithm to classify LEATs with a prominent oligodendroglioma-like component. CONCLUSIONS: Integrated histomolecular diagnosis of LEATs with a prominent oligodendroglioma-like component remains challenging. Because these tumours can be split into two major clusters of biological significance, the clinicopathological relevance of the four types recognised by the WHO CNS5 within this spectrum of tumours is questionable.

Fusiform dilatation of internal carotid artery after pterional but not subfrontal craniotomy in 6 patients.

PURPOSE: Our study aimed to evaluate potential risk factors for the development of FDICA after suprasellar tumor resection. MATERIALS AND METHOD: After reviewing all cases of pediatric patients who benefited from a suprasellar lesion resection in our two medical institutions, we found 6 patients with a FDICA. Surgical approach strategy (pterional or subfrontal approaches) was noted. Postoperative cranial MRI was performed in each patient 3 months after surgery and every year. When a FDICA occurred, MRI was performed 6 months after the diagnosis and 1 year later to detect any progression. RESULTS: There were 6 males with a mean age at treatment of 11 years (6 to 15). Pterional approach was performed in these 6 patients. At the 2 institutions, we have done at least 50 pterional craniotomies for suprasellar lesion resection. No FDICA was reported after subfrontal approach in 27 consecutive pediatric patients operated on from a craniopharyngioma. The delay between the surgery and the diagnosis of the FDICA was 9 months (3 to 17 months). No symptoms related to the FDICA were recorded. The mean maximal diameter of the aneurysm was 14 mm (10 to 21). ICA bifurcation was involved in 2 cases. Asymptomatic FDICA progression was noted in 2 cases but no treatment was proposed. CONCLUSION: The pathogenesis of FDICA is unclear, and might involve arterial wall necrosis caused by postoperative arachnoid fibrosis which might be worsened by the pterional approach.

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) presenting as a prenatally heterotopic hamartoma.

Dysplastic gangliocytoma of the cerebellum (DGC), also called Lhermitte-Duclos disease, is a rare lesion of the posterior fossa consisting of a diffuse hypertrophy of the cerebellar cortex. DGC frequently presents in young adults and rarely in childhood. Only 3 cases have been previously described in newborns. We present an uncommon case of DGC which was diagnosed in utero. The radiological presentation prenatally and at birth was similar to a heterotopic neuroglial brain tissue. MRI aspects evolved from T1/T2 isointense signals to hypoT1 and hyperT2 signals at the age of 1 year. The girl was then operated on total removal of the lesion which was performed with no postoperative complication. Genetics did not demonstrate any germline PTEN mutation or family history suggesting Cowden disease. Two years later, the child was doing well and MRI confirmed complete resection. This case illustrates the difficulties of diagnosing intracranial lesions in foetuses and newborns. Physicians caring for pregnant women and pediatrics should be aware that neoplasm-like lesions such as DGC may present as hamartomas. Surgical resection could then be discussed whenever possible.

Pneumosinus dilatans of the sphenoid and visual loss: when should the optic nerve be decompressed?

Pneumosinus dilatans of the sphenoid sinus is a rare disorder which can be responsible for visual impairment and blindness. We present the case of an adolescent female who experienced progressive decrease in right-eye vision over 2 years. CT scan of the head showed an extensive pneumatization of the sphenoid bone extending to the lesser wing of the sphenoid and to the anterior clinoid process on the right side. MRI revealed right nerve atrophy in the optic canal and in the posterior part of the orbit. A surgical decompression of the right optic canal was performed via an intradural fronto-pterional approach. Postoperatively, her vision worsened, and at 3 years the patient was able to count fingers at 2.5 m. Our case and literature review of symptomatic sphenoidal pneumosinus dilatans confirmed that visual prognosis in such cases depended on the preoperative visual status. Early surgical decompression should be proposed whenever possible, before signs of severe visual disorders and optic atrophy.

Ruptured intracranial arachnoid cysts in the subdural space: evaluation of subduro-peritoneal shunts in a pediatric population.

PURPOSE: Rupture of arachnoid cysts (AC) in the subdural space after trauma may cause a subacute/chronic subdural hematoma or a hygroma. Treatment of this complication still remains controversial, and no consensual strategy is to date clearly proposed. In this study, the authors evaluated the clinical and radiological evolution of patients treated by a subduro-peritoneal shunt for symptomatic subdural collections complicating ruptured AC. METHODS: Medical records of the 10 patients treated at our institution between January 2005 and December 2018 for a subdural collection associated with an intracranial AC were reviewed. Subduro-peritoneal shunts consisted of low-pressure valves from 2005 to 2012 (6 cases) and medium-pressure valves after 2012 (4 cases). RESULTS: A benign head trauma was retrospectively found in the history of 8 patients. The mean time to diagnosis ranged from 15 days to 5 months. Symptoms resulted mainly from intracranial hypertension. Six patients had an ipsilateral hygroma to the AC, 2 patients had a bilateral hygroma predominantly to the AC side, and 2 patients presented an ipsilateral chronic subdural hematoma. Arachnoid cysts were classified as Galassi I in 5 cases and Galassi II in 5 cases. Patients with chronic subdural hematoma were given a medium-pressure valve. Patients with subdural hygroma received a low-pressure valve in 6 cases and a medium-pressure valve in 2 cases. There were no complications during surgical procedures. All patients were rapidly free of symptoms after surgery and were discharged from hospital 1 to 4 days postoperatively. The subdural collection completely disappeared in all cases. In the long term, only 2 patients with low-pressure valves underwent shunt removal without any consequences, while a second surgical procedure was necessary to treat recurrence of intracranial hypertension in the 4 remaining cases. All the medium-pressure valves were removed without problems. The size of the AC was reduced in 3 cases, remained stable in 4 cases, and increased in 3 cases. No patients experienced recurrence of subdural collection during follow-up. CONCLUSIONS: Medium-pressure subduro-peritoneal shunts should be considered as part of the arsenal of surgical strategy in symptomatic ruptured AC in the subdural space. The procedure is simple with a very low morbidity, and it allows rapid improvement of symptoms. Although the shunt is located in the subdural space, we strongly recommend avoiding devices which may create an overdrainage and expose the patient to shunt dependency such as low-pressure shunts.

Interruptions in Surgery: A Comprehensive Review.

BACKGROUND: Recent literature showed that analysis of interruptions can contribute to evaluating the care process in the operating room, and thus, understanding potential errors that may occur during surgical procedures. The aim of this comprehensive review was to summarize current knowledge on the description and impact of interruptions in surgery. MATERIAL AND METHODS: A literature search was conducted according to a set of criteria in the databases MEDLINE, BASE, Cochrane's Library, and PsycINFO. RESULTS: 41 articles were included. Two main methodological approaches were found, observational in the OR, or controlled in an experimental simulated environment. Interruptions in the OR were manifold, and several classifications were used. The severity of interruptions differed according to the category of the interruptions. Interruptions were influenced by team familiarity and the expertise of the surgical team; high team familiarity and a high level of expertise decreased the frequency of interruptions. However, our literature search lacked controlled studies carried out in the OR. Interruptions seemed to increase the workload and stress of the surgical team and impair nontechnical skills, but no clear evidence of this was advanced. CONCLUSIONS: Interruptions are probably risk factors for errors in the operating room. However, there is as yet no clear evidence of the association of interruption frequency with errors in the operating room. There is a need to define and target interruptions, which should be reduced by putting safeguards in place, thereby allowing those which could be beneficial and neglecting those with no potential consequences.

Nontechnical Skills in Neurosurgery: A Systematic Review of the Literature.

BACKGROUND: Undesirable events in the neurosurgery operating theater have less often been the result of a technical error than of a dysfunction linked to nontechnical skills (NTSs). The essential aim of our study was to perform a systematic review of the reported data on NTS in neurosurgery. Our secondary objective was to identify the NTSs more specific to neurosurgery to define the training needs of neurosurgery trainees. METHODS: The MEDLINE and Cochrane Database of Systematic Reviews were searched according to the PRISMA (preferred reporting items for systematic reviews and meta-analysis) guidelines. The search initially identified 2132 reports, of which 21 were eligible for systematic study. Data were extracted from the report regarding study design, sample size, NTSs assessed, and assessment tools, and the key results were collected. RESULTS: Interpersonal skills (communication, teamwork), cognitive skills (decision making, situational awareness), and personal resource factors (coping with stress or fatigue) were specifically identified. No study had used assessment tools such as NOTECHS (nontechnical skills), NOTSS (nontechnical skills for surgeons), or OTAS (observational teamwork assessment for surgery). They were performed in a real environment in 11 cases, in a simulated environment in 9, and during theoretical teaching in 1 case. CONCLUSIONS: Very few studies have been performed concerning neurosurgical NTSs, despite the increasing the number of studies during the past few years on NTSs in other domains of surgery. Society has been concentrating more and more on the quality and safety of medical care. The development and application of NTS assessment tools is, therefore, essential to provide assistance in the training of future neurosurgeons.

Relationships Between Expertise, Crew Familiarity and Surgical Workflow Disruptions: An Observational Study.

BACKGROUND: Teamwork is an essential factor in reducing workflow disruption (WD) in the operating room. Team familiarity (TF) has been recognized as an antecedent to surgical quality and safety. To date, no study has examined the link between team members' role and expertise, TF and WD in surgical setting. This study aimed to examine the relationships between expertise, surgeon-scrub nurse familiarity and WD. METHODS: We observed a convenience sample of 12 elective neurosurgical procedures carried out by 4 surgeons and 11 SN with different levels of expertise and different degrees of familiarity between surgeons and SN. We calculated the number of WD per unit of coding time to control for the duration of operation. We explored the type and frequency of WD, and the differences between the surgeons and SN. We examined the relationships between duration of WD, staff expertise and surgeon-scrub nurse familiarity. RESULTS: 9.91% of the coded surgical time concerned WD. The most frequent causes of WD were distractions (29.7%) and colleagues' interruptions (25.2%). This proportion was seen for SN, whereas teaching moments and colleagues' interruptions were the most frequent WD for surgeons. The WD was less high among expert surgeons and less frequent when surgeon was familiar with SN. CONCLUSIONS: The frequency of WD during surgical time can compromise surgical quality and patient safety. WD seems to decrease in teams with high levels of surgeon-scrub nurse familiarity and with development of surgical expertise. Favoring TF and giving feedback to the team about WD issues could be interesting ways to improve teamwork.

Comparison of neurogenic lower urinary tract dysfunctions in open versus closed spinal dysraphism: A prospective cross-sectional study of 318 patients.

AIMS: To compare the neurogenic lower urinary tract dysfunction (NLUTD) in patients with closed spinal dysraphism (CSD) versus patients with open spinal dysraphism (OSD) as well as their management patterns. METHODS: A prospective cross-sectional study was conducted between September 2007 and December 2015 including all spina bifida patients seen at the multidisciplinary French national referral center for spina bifida. NLUTD and its management were compared between the OSD and CSD groups. RESULTS: Three hundred and eighteen patients were included for analysis: 100 with a CSD (31.5%) and 218 with an OSD (68.6%). The prevalence of urinary incontinence did not differ significantly between the two groups (43% vs 52.8%; P = 0.11), the mean Qualiveen score was also similar (2.7 vs 2.5, P = 0.22). The voiding mechanism was clean intermittent catheterization, spontaneous voiding, suprapubic tube, and ileal conduit in 55% versus 44%; 29.8% versus 47%; 2.8% versus 3% and 11.9% versus 6% of OSD and CSD patients, respectively (P = 0.02). There were comparable prevalences of detrusor overactivity (36.5% vs 38.8%; P = 0.68) and impaired bladder compliance (34.9% vs 31.7%; P = 0.56) in both groups. Augmentation cystoplasty was more common in patients with OSD (32.1% vs 11%; P < 0.0001). CONCLUSIONS: In this prospective cohort, NLUTD were more common in OSD with a higher rate of patients requiring a surgical treatment and a lower rate of patients with preserved spontaneous voiding. However, when present, NLUTD was as severe and troublesome in patients with closed versus open spinal dysraphism.

Edema of the optic tract in patients with tumors of the sellar region: clinical and visual implications in the pediatric population.

OBJECTIVE Tumor-related edema of the optic tract (EOT) corresponds to a preferential posterior distribution of peritumoral edema along the white matter tract of the visual system. To date, the consequences of EOT have never been evaluated specifically in the pediatric population. In this study, the authors attempted to identify clinical and radiological features associated with the development of EOT and the specific influence of this edema on visual function. METHODS A retrospective review was performed of data collected from patients younger than 18 years who underwent surgery for a tumor in the sellar region at the authors' institution between January 2005 and January 2016. Data were collected on patient characteristics, ophthalmological evaluations, and neuroimaging findings. To evaluate and compare visual function impairment, ophthalmological data were converted to a global visual function score, which took into account visual acuity, visual field evaluations, and laterality deficiencies. The visual acuity score was defined according to the International Classification of Diseases, 10th Revision. Visual field deficiencies were converted to a score of 0-2. Two opposing groups were then distinguished according to the presence or absence of EOT. Visual acuity, visual field results, and global scores were compared between groups before and after treatment. RESULTS Twenty-six patients were included in the study: 17 patients with craniopharyngioma, 3 patients with pilocytic astrocytoma, 2 patients with ganglioglioma, 2 patients with germ cell tumor, 1 patient with macroprolactinoma, and 1 patient with Rathke's cleft cyst. There were 11 children in the group with edema and 15 children in the group without edema. None of the following criteria were statistically different between the 2 groups: age, sex, clinical symptoms at presentation (endocrine deficiency or intracranial hypertension signs), incidence of hydrocephalus, compression of the optic tracts and mass effect on the optic chiasm, tumor size and localization, presence of intratumoral cysts, treatment, type of tumor, or recurrence. The median global visual function and visual acuity scores were not significantly different between the groups either at presentation or at final evaluation. The visual field score was lower (i.e., more deficiency) in the group with edema than in the group without edema (p < 0.05); 89% of the patients with edema had severe or mild visual field impairment versus only 40% of the patients without edema. At the final examination after treatment, the visual field scores were not different between the 2 groups. Although not significant, the number of patients with optic disc pallor was greater in the group without edema both at diagnosis and at final examination. CONCLUSIONS This study confirms that EOT in the context of sellar region tumor in children is not necessarily associated with a less-favorable visual prognosis.

Surgical skills: Can learning curves be computed from recordings of surgical activities?

PURPOSE: Surgery is one of the riskiest and most important medical acts that are performed today. The need to improve patient outcomes and surgeon training, and to reduce the costs of surgery, has motivated the equipment of operating rooms with sensors that record surgical interventions. The richness and complexity of the data that are collected call for new methods to support computer-assisted surgery. The aim of this paper is to support the monitoring of junior surgeons learning their surgical skill sets. METHODS: Our method is fully automatic and takes as input a series of surgical interventions each represented by a low-level recording of all activities performed by the surgeon during the intervention (e.g., cut the skin with a scalpel). Our method produces a curve describing the process of standardization of the behavior of junior surgeons. Given the fact that junior surgeons receive constant feedback from senior surgeons during surgery, these curves can be directly interpreted as learning curves. RESULTS: Our method is assessed using the behavior of a junior surgeon in anterior cervical discectomy and fusion surgery over his first three years after residency. They revealed the ability of the method to accurately represent the surgical skill evolution. We also showed that the learning curves can be computed by phases allowing a finer evaluation of the skill progression. CONCLUSION: Preliminary results suggest that our approach constitutes a useful addition to surgical training monitoring.

Finding discriminative and interpretable patterns in sequences of surgical activities.

OBJECTIVE: Surgery is one of the riskiest and most important medical acts that is performed today. Understanding the ways in which surgeries are similar or different from each other is of major interest to understand and analyze surgical behaviors. This article addresses the issue of identifying discriminative patterns of surgical practice from recordings of surgeries. These recordings are sequences of low-level surgical activities representing the actions performed by surgeons during surgeries. MATERIALS AND METHOD: To discover patterns that are specific to a group of surgeries, we use the vector space model (VSM) which is originally an algebraic model for representing text documents. We split long sequences of surgical activities into subsequences of consecutive activities. We then compute the relative frequencies of these subsequences using the tf*idf framework and we use the Cosine similarity to classify the sequences. This process makes it possible to discover which patterns discriminate one set of surgeries recordings from another set. RESULTS: Experiments were performed on 40 neurosurgeries of anterior cervical discectomy (ACD). The results demonstrate that our method accurately identifies patterns that can discriminate between (1) locations where the surgery took place, (2) levels of expertise of surgeons (i.e., expert vs. intermediate) and even (3) individual surgeons who performed the intervention. We also show how the tf*idf weight vector can be used to both visualize the most interesting patterns and to highlight the parts of a given surgery that are the most interesting. CONCLUSIONS: Identifying patterns that discriminate groups of surgeon is a very important step in improving the understanding of surgical processes. The proposed method finds discriminative and interpretable patterns in sequences of surgical activities. Our approach provides intuitive results, as it identifies automatically the set of patterns explaining the differences between the groups.