Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the foot and ankle – A series of 14 cases

BackgroundThe surgical treatment for osteoid osteoma (OO) in the foot and ankle is challenging. It is difficult to locate the lesion and the anatomy is crowded by sensitive structures. The purpose of this study was to describe the outcomes of navigated mini open-intralesional curettage (NMIC) or navigated minimally invasive radiofrequency ablation (NMRFA) in treating these lesions.MethodsAll patients who underwent surgery for OO in the foot and ankle between 2015 and 2020 were included. O-arm navigation was used in All procedures. The choice of NMIC versus NMRFA was made by the surgeon according to the location of the lesion and its proximity to sensitive anatomic structures.ResultsFourteen patients were included. Ten were operated by NMRFA and 4 by NMIC. All patients’ symptoms related to OO resolved following a single procedure. Average AOFAS score increased by 18.7 (P < .001). Three patients had the following complications: pathologic fracture, superficial infection and transient deep peroneal nerve sensory loss.ConclusionNavigated surgical treatment of OO in the foot and ankle is accurate, efficient and safe.     

导航系统辅助下颈椎椎弓根螺钉置钉准确性的实验研究

目的：评价导航系统辅助下颈椎（C3～C7）椎弓根螺钉内固定置钉的准确性.方法：将32具成人尸体颈椎标本随机分为4组,分别采用盲法、透视法、透视导航法和CT导航法进行下颈椎椎弓根螺钉置入.术后采用标本大体解剖观察的方法评价置钉准确性.分优（螺钉完全在椎弓根内）、可（仅有螺纹穿出,对周围组织无损伤）和差（螺钉明显穿出）进行统计.结果：共置入螺钉318枚.盲法80枚,平均手术时间27min,优29枚（36 3%）、可21枚（26.3%）、差30枚（37.5%）;透视法78枚（有1例C4、C5右侧椎弓根均细小,不能容纳3.5mm螺钉）,平均手术时间112min,优35枚（44.9%）、可29枚（37.2%）、差14枚（17.9%）;透视导航法80枚,平均手术时间69min,优34枚（42.5%）,可36枚（45%）,差10枚（12.5%）;CT导航法80枚,平均手术时间98min,优70枚（87.5%）、可10枚（12.5%）.各组间手术时间均有显著性差异（P＜0.05）,透视法与透视导航法的置钉准确率间无显著性差异,其余各组间均有显著性差异（P＜0.05）.结论：单纯根据术前影像结果盲法行下颈椎椎弓根螺钉内固定不安全.透视法和透视导航法可提高置钉准确性,但手术风险仍较大,透视导航法比透视法置钉的手术时间缩短.CT导航法并未比透视法增加手术时间,但置钉准确性显著提高.     

计算机辅助手术的发展状况和展望——参加第17届国际计算机辅助放射学及手术大会（CARS 03）后记

计算机辅助手术和治疗(IGST)是一个新兴的多学科交叉的研究领域,近年来取得了飞速的发展.作为该领域顶级会议之一的国际计算机辅助放射学及手术大会(CARS2003)于2003年6月25至28日在英国伦敦伊丽莎白二世国际会议中心隆重举行了第17届会议.本文将对这次大会作一回顾和总结,内容包括科学论文方面的评论和产品展览方面的情况.     

Fusion of vestibular and podokinesthetic information during self-turning towards instructed targets

When observers step about their vertical axis ("active turning") without vision they dispose of essentially two sources of information that can tell them by how much they have turned: the vestibular cue which reflects head rotation in space and the "podokinesthetic" cue, a compound of leg proprioceptive afferents and efference copy signals which reflects the observer's motion relative to his support. We ask how these two cues are fused in the process leading to the perception of self-displacement during active turning. To this end we compared the performance of observers in three angular navigation tasks which differed with regard to the number and type of available motion cues: (1) Passive rotation, vestibular cue ( ves) only; observers are standing on a platform which is being rotated. (2) Treadmill stepping, podokinesthetic cue ( pod) only; observers step counter to the rotating platform so as to remain stable in space. (3) Active turning, ves and pod available; observers step around on the stationary platform. In all three tasks, angular velocity varied from trial to trial (15, 30, 60 degrees /s) but was constant during trials. Perception was probed by having the observers signal when they thought to have reached a previously instructed angular displacement, either in space or relative to the platform ("target"; range 60-1080 degrees ). Performance was quantified in terms of the targeting gain (displacement reached by the observer divided by target angle) and of the random error ( E(r)), which records an observer's deviation during single trials from his average performance. Confirming previous observations, E(r) was found to be significantly smaller during active turning than during passive turning, and we now complement these observations by showing that it is also significantly smaller than during treadmill stepping. This behaviour of E(r) is compatible with the idea that ves and pod be averaged during active turning. On the other hand, the observed characteristics of the targeting gain ( G(T)) support this idea only for the case of fast rotations (60 degrees /s); at lower velocities, the gain found during active turning was clearly not the average of the G(T) values recorded in the passive and the treadmill modes. We therefore also discuss alternative scenarios as to how ves and pod could interact, among these one based on the concept of a vestibular eigenmodel. A common denominator of these scenarios is that ves assumes the role of a prerequisite for an optimal use of pod during turning on a stationary support, without itself entering the calculation of displacement perception; this perception would be based exclusively on pod. Finally, it was a consistent observation that during passive rotations cognitive mechanisms fill in for the decaying vestibular signal in the context of the present navigation task, enabling observers to achieve large displacements surprisingly well although the duration of these movements exceeds by far the conventionally cited value of the central vestibular time constant (=20 s).     

Neue Konzepte in der bildgestützten Chirurgie: automatische Patientenregistrierung anhand von Kiefer und Ohrmuschel

ZusammenfassungFragestellung Mit Hilfe einer automatischen und markerlosen Patientenregistrierung auf der Basis natürlicher anatomischer Grenzflächen kann im Vorfeld eines computergestützten chirurgischen Eingriffs eine deutliche Reduktion von Strahlenbelastung und logistischem Aufwand erreicht werden, weil auf das Platzieren und Einmessen röntgensichtbarer Referenzmarker verzichtet werden kann. In einer klinischen Studie sollte überprüft werden, ob neben dem Gesicht auch die Ohrmuschel sowie der Ober- und Unterkiefer als anatomische Grenzfläche zur intraoperativen Registrierung der Patientenlage verwendet werden können.Material und Methode Vor einem chirurgischen Eingriff wurde die räumliche Lage von 20 Patienten mit Hilfe eines hochauflösenden 3D-Laserscans registriert und markerlos mit dem präoperativen CT-Datensatz korreliert. Indikation für den chirurgischen Eingriff waren Tumoren, skelettale Fehlbildungen und Fremdkörper. Die Ohrmuschel sowie der Ober- und Unterkiefer wurden dabei zur Registrierung der Patientenlage genutzt. Durch eine zusätzliche konventionelle markerbasierte Patientenregistrierung wurde die Genauigkeit dieser neuen—an sich markerlosen—Methode klinisch evaluiert.Ergebnisse und Schlussfolgerungen Die markerlose Patientenregistrierung auf der Basis natürlicher anatomischer Grenzflächen war im Bereich des Oberkiefers verlässlich möglich (Abweichung: 0,8±0,3 mm), im Unterkiefer haben Zunge und beweglicher Mundboden zu geometrischer Inkongruenz und mangelhafter Laserregistrierung geführt. Mit Hilfe der Ohrmuschelregistrierung war eine hohe Präzision zu erzielen, solange die Ohrmuschel während der CT-Bildgebung oder während des Laserscannens nicht deformiert wurde (Abweichung: 1,9±0,9 mm). Die übliche CT-Bildakquisition mit Kopfschale führte jedoch bei mehr als der Hälfte der Patienten zu temporären Ohrmuscheldeformierungen, die eine exakte Laserscanregistrierung unmöglich machte.     

Enriched environment has limited capacity for the correction of hippocampal memory-dependent schizoid behaviors in rats with early postnatal NMDAR dysfunction

Pre- and early postnatal stress can cause dysfunction of the N-methyl-d-aspartate receptor (NMDAR) and thereby promote the development of hippocampus memory-dependent schizoid abnormalities of navigation in space, time, and knowledge. An enriched environment improves mental abilities in humans and animals. Whether an enriched environment can prevent the development of schizoid symptoms induced by neonatal NMDAR dysfunction was the central question of our paper. The experimental animals were Wistar rats. Early postnatal NMDAR dysfunction was created by systemic treatment of rat pups with the NMDAR antagonist MK-801 at PD10–20 days. During the development period (PD21–90 days), the rats were reared in cognitively and physically enriched cages. Adult age rats were tested on navigation based on pattern separation and episodic memory in the open field and on auto-hetero-associations based on episodic and semantic memory in a step-through passive avoidance task. The results showed that postnatal NMDAR antagonism caused abnormal behaviors in both tests. An enriched environment prevented deficits in the development of navigation in space based on pattern separation and hetero-associations based on semantic memory. However, an enriched environment was unable to rescue navigation in space and auto-associations based on episodic memory. These data may contribute to the understanding that an enriched environment has a limited capacity for therapeutic interventions in protecting the development of schizoid syndromes in children and adolescents.     

Accuracy analysis of computer-assisted surgery for femoral trochanteric fracture using a fluoroscopic navigation system: Stryker ADAPT®system

PurposeADAPT is a fluoroscopic computer-assisted surgery system which intraoperatively shows the distance from the tip of the screw to the surface of the femoral head, tip-to-head-surface distance (TSD), and the tip-apex distance (TAD) advocated by Baumgaertner et al. The study evaluated the accuracy of ADAPT.Patients and methodsA total of 55 patients operated with ADAPT between August 2016 and March 2017 were included as subjects. TSD and TAD were measured postoperatively using computed tomography (CT) and X-rays. The intraclass correlation coefficient (ICC) was checked in advance. The error was defined as the difference between postoperative and intraoperative measurement values of ADAPT. Summary statistics, root mean square errors (RMSEs), and correlations were evaluated.ResultsICC was 0.94 [95% CI: 0.90–0.96] in TSD and 0.99 [95% CI: 0.98–0.99] in TAD. The error was −0.35 mm (−1.83 mm to 1.12 mm) in TSD and +0.63 mm (−5.65 mm to 4.59 mm) in TAD. RMSE was 0.63 mm in TSD and 1.53 mm in TAD. Pearson’s correlation coefficient was 0.79 [95% CI: 0.66–0.87] in TSD and 0.83 [95% CI: 0.72–0.89] in TAD. There were no adverse events with ADAPT use.ConclusionADAPT is highly accurate and useful in guiding surgeons in properly positioning the screws.