Management of sagittal craniosynostosis: morphological comparison of eight surgical techniques

The aim of this study was to carry out a retrospective multicentre study comparing the morphological outcome of 8 techniques used for the management of sagittal synostosis versus a large cohort of control patients. Computed tomographic (CT) images were obtained from children CT-scanned for non-craniosynostosis related events (n = 241) and SS patients at preoperative and postoperative follow-up stages (n = 101). No significant difference in morphological outcomes was observed between the techniques considered in this study. However, the majority of techniques showed a tendency for relapse. Further, the more invasive procedures at older ages seem to lead to larger intracranial volume compared to less invasive techniques at younger ages. This study can be a first step towards future multicentre studies, comparing surgical results and offering a possibility for objective benchmarking of outcomes between methods and centres.     

Segmentation and visualization of the human cranial bone by T2* approximation using ultra-short echo time (UTE) magnetic resonance imaging

Segmentation of the human cranial bone from MRI data is challenging, because compact bone is characterized by very short transverse relaxation times and typically produces no signal when using conventional magnetic resonance imaging (MRI) sequences. In this work, we propose a fully automated segmentation algorithm, which uses dual-echo, ultra-short echo-time (UTE) MRI data. The segmentation was initialized by interval thresholding of approximated T₂* relaxation time maps in the range of 1 ms < T₂* < 3 ms. This parameter range was derived from a manual region-of-interest analysis of high resolution data of the cranial layers, resulting in average T₂* relaxation times of 1.7 ± 0.3 ms in the lamina externa, 2.5 ± 0.3 ms in the diploe and 1.7 ± 0.2 ms in the lamina interna. Segmentations were performed based on data of 8 healthy volunteers that were acquired with different acquisition parameters and spatial resolutions to test the stability of the algorithm. Comparison with computed tomography data demonstrated close agreement with the segmented UTE MRI data. Visualization of the segmented cranial bone was performed by volumetric rendering and by using the approximated T₂* values for color coding, clearly visualizing the cranial sutures as well as their intersections.     

Patient Wellbeing and Quality of Life After Nasoseptal Flap Closure for Endoscopic Skull Base Reconstruction

BackgroundThe endoscopic endonasal approach to the skull base avoids some of the surgical morbidity associated with a transcranial approach, however it often results in large skull-base defects requiring secure closure. The nasoseptal flap has become the preferred method for closure of such defects but may be associated with its own morbidity.MethodsA consecutive cohort of patients with skull base pathology with prospectively collected quality of life data using ASBQ and SNOT was analysed. They were grouped into those who received a nasoseptal flap and those who did not. Pre-operative total ASBQ and SNOT scores, and their individual components, were compared to data collected at days 1, 3, and 7; six-weeks; and 3, 6, and 12-months postoperatively.ResultsOf 158 patients available for analysis, nasoseptal flaps were performed in 52 (33%). Average follow-up (±standard deviation) was 8.1 ± 3.9 months for ASBQ data and 8.2 ± 3.8 months for SNOT data. In the first post-operative week, nasal symptoms and otalgia were worse in the flap group. At six-weeks and beyond, there was no difference between groups in overall ASBQ or SNOT scores, or in the rate of clinically-significant improvement in SNOT or ASBQ scores or their components.ConclusionIn the largest cohort of patients to date, the use of a nasoseptal flap is associated with nasal symptoms and otalgia in the acute post-operative period, but is not associated with any long-term detriment to quality of life after endoscopic skull base surgery.     

Anatomical study of jugular foramen in the neck

IntroductionThe anatomical complexity of the jugular foramen makes surgical procedures in this region delicate and difficult. Due to the advances in surgical techniques, approaches to the jugular foramen became more frequent, requiring improvement of the knowledge of this region anatomy.ObjectiveTo study the anatomy of the jugular foramen, internal jugular vein and glossopharyngeal, vagus and accessory nerves, and to identify the anatomical relationships among these structures in the jugular foramen region and lateral-pharyngeal space.MethodsA total of 60 sides of 30 non-embalmed cadavers were examined few hours after death. The diameters of the jugular foramen and its anatomical relationships were analyzed.ResultsThe diameters of the jugular foramen and internal jugular vein were greater on the right side in most studied specimens. The inferior petrosal sinus ended in the internal jugular vein up to 40 mm below the jugular foramen; in 5% of cases. The glossopharyngeal nerve exhibited an intimate anatomical relationship with the styloglossus muscle after exiting the skull, and the vagal nerve had a similar relationship with the hypoglossal nerve. The accessory nerve passed around the internal jugular vein via its anterior wall in 71.7% of cadavers.ConclusionAnatomical variations were found in the dimensions of the jugular foramen and the internal jugular vein, which were larger in size on the right side of most studied bodies; variations also occurred in the trajectory and anatomical relationships of the nerves. The petrosal sinus can join the internal jugular vein below the foramen.     

Brain tissue oxygenation during transnasal endoscopic skull base procedures

PurposeWe aimed to study brain tissue oxygenation during the period of controlled reduction of arterial blood pressure – a maneuver often used in extended endoscopic skull base surgery for bloodless operative field.MethodsIntracranial pressure, arterial blood pressure and the resultant cerebral perfusion pressure were measured during extended endoscopic skull base surgery in 5 patients with diagnosed tumors of the skull base and arterial hypertension. Simultaneously, in those patients, we measured partial pressure of oxygen in the brain parenchyma (PbtO₂).ResultsValues of PbtO₂ lower than 15 mm Hg (risk of brain ischemia) were observed in 3 patients for periods of 40 min, 110 min and 123 min, respectively. In 2 of these patients, no hypotension (mean arterial pressure <65 mm Hg) was necessary for bloodless operative field. Another 2 patients had PbtO₂ above 30 mm Hg at the time when their mean arterial pressure was below 65 mm Hg. The time course of PbtO₂ followed that of cerebral perfusion pressure with a time lag of 40–60 s in all patients.ConclusionModerate reduction of arterial pressure, often used to obtain bloodless operative field during extended endoscopic skull base surgery, may in patients with the medical history of arterial hypertension be associated with critically low values of partial oxygen pressure in brain tissue.     

The sellar barrier and intraoperative CSF leak in elderly patients

Cerebral spinal fluid (CSF) leak is a significant complication in pituitary surgery, increasing both patient morbidity and mortality. In a recent publication, Campero et al. observed worse postoperative prognosis and increased risk of intraoperative CSF leak in patients with reduced sellar barrier thickness. The objective of this study was to analyze the association between sellar barrier thickness and intraoperative CSF leak in older individuals. A retrospective review was conducted of 44 transsphenoidal surgery resections for pituitary adenomas, 24 microscopic and 20 purely endoscopic procedures. Presence of intraoperative CSF fistula was significantly greater in patients with weak sellar barrier (thickness under 1 mm), compared to strong sellar barrier (52.94% vs 3.70% p < 0.0001, respectively). Application of this novel concept may help improve surgical technique selection as well as predict risk of intraoperative CSF leak and need for eventual use of flaps for reconstruction.     

Intraoperative lateral rectus electromyographic recordings optimized by deep intraorbital needle electrodes

ObjectiveWe demonstrate the advantages and safety of long, intraorbitally-placed needle electrodes, compared to standard-length subdermal electrodes, when recording lateral rectus electromyography (EMG) during intracranial surgeries.MethodsInsulated 25 mm and uninsulated 13 mm needle electrodes, aimed at the lateral rectus muscle, were placed in parallel during 10 intracranial surgeries, examining spontaneous and stimulation-induced EMG activities. Postoperative complications in these patients were reviewed, alongside additional patients who underwent long electrode placement in the lateral rectus.ResultsIn 40 stimulation-induced recordings from 10 patients, the 25 mm electrodes recorded 6- to 26-fold greater amplitude EMG waveforms than the 13 mm electrodes. The 13 mm electrodes detected greater unwanted volume conduction upon facial nerve stimulation, typically exceeding the amplitude of abducens nerve stimulation. Except for one case with lateral canthus ecchymosis, no clinical or radiographic complications occurred in 36 patients (41 lateral rectus muscles) following needle placement.ConclusionsIntramuscular recordings from long electrode in the lateral rectus offers more reliable EMG monitoring than 13 mm needles, with excellent discrimination between abducens and facial nerve stimulations, and without significant complications from needle placement.SignificanceLong intramuscular electrode within the orbit for lateral rectus EMG recording is practical and reliable for abducens nerve monitoring.     

基于三维打印技术制作钛合金修复体修补兔颅骨缺损的研究

目的 通过三维(3D)打印技术协助新西兰兔个体化钛合金修复体进行预制行颅骨缺损修补,探讨3D技术在颅骨缺损重建中的运用价值。方法 选取健康雄性新西兰兔12只制作颅骨缺损模型成功后,螺旋64排CT薄层无间距逐层扫描获得断层数据后进行格式转换构建三维颅骨立体模型,利用3D打印机进行修复体的三维原型制造,结合模型利用钛合金修复体进行骨性缺损区域精准修补。结果 钛合金修复体与骨性缺损区域及边缘组织契合满意,术中一次固定到位,避免反复剪裁,操作阻力小,伤口均一期愈合,不良反应较少,未观察到颅内感染、头皮溃烂、钛合金外露、排出及移位等不良现象。术后颅骨外形与健侧相比更美观、功能修复满意,并邀请三位同行医师评估修复满意度,以100%为满意,取平均值,满意率为98.78%。结论 与颅骨缺损修补术相比,3D打印技术可快速、精准结合钛合金,对个体化修复颅骨缺损区尤其是复杂解剖形态“适形”可能更胜一筹,值得临床推广运用。     

Dental and skull anomalies in feral coypu, Myocastor coypus

The study of dental and skull abnormalities of wild animals can provide useful information for comparative studies. Although studies of captive and laboratory rodents have been published, there are few reports on wild populations. We examined anomalous and pathological conditions in the skulls of feral coypus, Myocastor coypus, from Aichi Prefecture, Japan, and identified the types of abnormality. Of the 203 coypu skulls of various ages examined, 19 specimens (9.4%) had abnormalities. A total of 23 anomalies were divisible into three categories: dental diseases, dental injuries and skull injuries. Seven specimens (3.4%) had evidence of periodontal disease in the cheek teeth, and one specimen (0.5%) had caries. Seven specimens (3.4%) had broken upper or lower incisors. Four specimens (2.0%) had injured cranial bones and three (1.4%) had fractures near the zygomatic arch. A single specimen (0.5%) had a deformed rostrum. No statistically significant differences between the genders were found in any category (chi2 test: P < 0.05). The incidence of dental disease appeared to be related to the biological characteristics of this species, i.e., long lifespan, herbivorous diet and molar crown morphology. By contrast, dental and skull injuries appeared to be due to trauma caused when farmers attacked feral coypus.