OBJECTIVEChiari malformation type II (CM-II) in myelomeningocele is associated with a significant rate of mortality and poor outcome. Death is frequently heralded by the onset or progression of neurological symptoms. The authors sought to identify predictors of poor outcome and mortality within the myelomeningocele population at Children’s Hospital of Pittsburgh.METHODSA retrospective chart and radiology review was performed on all infants who underwent primary closure of a myelomeningocele defect at Children’s Hospital of Pittsburgh between the years of 1995 and 2015. Preoperative symptoms and signs leading to CM-II decompression, as well as operative details and postoperative changes in these symptoms and signs, were investigated in detail and correlated to outcome. Poor outcome was defined as death, stridor, or ventilator dependence. Deceased patients were separately assessed within this subgroup.RESULTSThirty-two (21%) of 153 patients were found to have symptomatic CM-II. Of the 32 patients meeting inclusion criteria, 12 (38%) had poor outcomes. Eight patients (25%) died since initial presentation; 5 of these patients (16% of the overall cohort) died within the 1st year of life and 3 (9%) died during adolescence. Seven (88%) of the 8 patients who died had central apnea on presentation (p = 0.001) and 7 (44%) of the 16 patients who developed symptoms in the first 3 months of life died, compared with 1 (6.3%) of 16 who developed symptoms later in childhood (p = 0.04). The median Apgar score at 1 minute was 4.5 for patients who died and 8 for surviving patients (p = 0.006). The median diameter of the myelomeningocele defect was 5.75 cm for patients who died and 5 for those who survived (p = 0.01). The anatomical level of defect trended toward higher levels in patients who died, with 4 patients in that group having an anatomical level at L-2 or higher compared with 5 of the surviving patients (p = 0.001). The median initial head circumference for the 5 patients dying in the 1st year of life was 41.5 cm, versus 34 cm for all other patients (p = 0.01).CONCLUSIONSCM-II in spina bifida is associated with a significant mortality rate even when surgical intervention is performed. Death is more frequent in symptomatic patients presenting prior to 1 year of age. Late deaths are associated with symptom progression despite aggressive surgical and medical intervention. In this patient cohort, death was more likely in patients with symptomatic presentation during the first 3 months of life, low Apgar scores, large myelomeningocele defects, early central apnea, and large head circumference at birth.

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This paper surveys both the clinical applications and main technical innovations related to steered needles, with an emphasis on neurosurgery. Technical innovations generally center on curvilinear robots that can adopt a complex path that circumvents critical structures and eloquent brain tissue. These advances include several needle-steering approaches, which consist of tip-based, lengthwise, base motion-driven, and tissue-centered steering strategies. This paper also describes foundational mathematical models for steering, where potential fields, nonholonomic bicycle-like models, spring models, and stochastic approaches are cited. In addition, practical path planning systems are also addressed, where we cite uncertainty modeling in path planning, intraoperative soft tissue shift estimation through imaging scans acquired during the procedure, and simulation-based prediction. Neurosurgical scenarios tend to emphasize straight needles so far, and span deep-brain stimulation (DBS), stereoelectroencephalography (SEEG), intracerebral drug delivery (IDD), stereotactic brain biopsy (SBB), stereotactic needle aspiration for hematoma, cysts and abscesses, and brachytherapy as well as thermal ablation of brain tumors and seizure-generating regions. We emphasize therapeutic considerations and complications that have been documented in conjunction with these applications.

Zusammenfassung In Versuchen an Leberschnitten sowie isolierten Kehlkopfmuskeln von Lämmern wurde untersucht, wie sich Alter und Vormagenentwicklung auf die Aufnahme der nicht metabolisierbaren Modellaminosäre α‐Aminoisobuttersäure (AIB) in die Leber‐ und Muskelzelle auswirken. Die gegen ein Konzentrationsgefälle erfolgende Aufnahme von AIB in die Leber‐ und Muskelzelle war bei 1–6 Tage alten Lämmern signifikant höher als bei 2,5–4 Monate alten Lämmern (Schafe), deren Vormagenentwicklung bereits weit fortgeschritten war. Dieser Unterschied ist altersbedingt und hängt somit nicht mit der Vormagenentwicklung zusammen, da sich bei gleichaltrigen Lämmern (Alter: 2–3 Monate), die auf Grund verschiedenartiger Fütterung (Milchfütterung bzw. Fütterung von Heu und Kraftfutter) deutliche Unterschiede in der Vormagenentwicklung aufwiesen, keine derartigen Gruppendifferenzen ergaben. Bei 1–6 Tage alten Lämmern akkumulierte AIB in der Leber‐ und Muskelzelle in gleichem Umfang gegen ein Konzentrationsgefälle, während bei 2–4 Monate alten Lämmern, unabhängig von der Vormagenentwicklung, für die Akkumulation von AIB in der Leberzelle höhere Werte erhalten wurden, als dies für die Muskelzelle der Fall war. Der altersabhängige Rückgang der AIB‐Aufnahme in die Leber‐ und Muskelzelle wird mit der Abnahme der Proteinansatzkapazität in Verbindung gebracht. Summary In vitro studies on amino acid uptake by liver and muscle cells in lambs In experiments with liver slices and isolated larynx muscles of lambs it was investigated to what extent uptake of the non‐metabolizable model amino acid α‐aminoisobutyric acid (AIB) by liver and muscle cells is affected by age and forestomach development. Uptake of AIB against a concentration gradient into the liver and muscle cell was significantly higher in lambs 1–6 days of age than in 2,5–4 months old lambs, whose forestomachs were well developed. This difference is due to the age difference of the animals and has nothing to do with the different forestomach development, since there was no such group difference between lambs of the same age (age: 2–3 months), which because of different feeding (milk versus hay and concentrate) showed a large discrepancy in forestomach development. In lambs, 1–6 days old, AIB accumulated to the same extent in the liver and muscle cell, while in lambs aged 2–4 months, independent of forestomach development, AIB accumulation was higher in the liver cell than in the muscle cell. The age‐dependent reduction of AIB uptake by liver and muscle cells might be attributable to the concomitant decline of protein synthesis. Résumé Recherches in vitro sur l'absorption des acides aminés dans le foie et la cellule musculaire chez l'agneau On a cherché à savoir lors d'essais sur des coupes hépatiques et des muscles isolés du larynx chez des agneaux comment l'âge et le développement des estomacs agissaient sur l'absorption de l'acide aminé modèle non métabolisable (acide aminoisobutyrique AIB) dans le foie et la cellule musculaire. Comparée à une chute de concentration, l'absorption...