Intraoperative MRI and epilepsy surgery

Intraoperative imaging, in particular intraoperative MRI, is a developing area in neurosurgery and its role is currently being evaluated. Its role in epilepsy surgery has not been defined yet and its use has been limited. In our experience with a compact and mobile low-field intraoperative MRI system, a few epilepsy surgeries have been performed using this technique. As the integration of imaging and functional data plays an important role in the planning of epilepsy surgery, intraoperative verification of the surgical result may be highly valuable. Therefore, teams that have access to intraoperative MRI should be encouraged to use this technique prospectively to evaluate its current relevance in epilepsy surgery.     

Robotics in neurosurgery: state of the art and future technological challenges

The use of robotic technologies to assist surgeons was conceptually described almost thirty years ago but has only recently become feasible. In Neurosurgery, medical robots have been applied to neurosurgery for over 19 years. Nevertheless this field remains unknown to most neurosurgeons. The intrinsic characteristics of robots, such as high precision, repeatability and endurance make them ideal surgeon's assistants. Unfortunately, limitations in the current available systems make its use limited to very few centers in the world. During the last decade, important efforts have been made between academic and industry partnerships to develop robots suitable for use in the operating room environment. Although some applications have been successful in areas of laparoscopic surgery and orthopaedics, Neurosurgery has presented a major challenge due to the eloquence of the surrounding anatomy. This review focuses on the application of medical robotics in neurosurgery. The paper begins with an overview of the development of the medical robotics, followed by the current clinical applications in neurosurgery and an analysis of current limitations. We discuss robotic applications based in our own experience in the field. Next, we discuss the technological challenges and research areas to overcome those limitations, including some of our current research approaches for future progress in the field.     

Surgical robotics: a review and neurosurgical prototype development

PURPOSE: The purpose of this article is to update the neurosurgical community on the expanding field of surgical robotics and to present the design of a novel neurosurgical prototype. It is intended to mimic standard technique and deploy conventional microsurgical tools. The intention is to ease its integration into the "nervous system" of both the traditional operating room and surgeon. CONCEPT: To permit benefit from updated intraoperative imaging, magnetic resonance imaging-compatible materials were incorporated into the design. Advanced haptics, optics, and auditory communication with the surgical site recreate the sight, sound, and feel of neurosurgery. RATIONALE: Magnification and advanced imaging have pushed surgeons to the limit of their dexterity and stamina. Robots, in contrast, are indefatigable and have superior spatial resolution and geometric accuracy. The use of tremor filters and motion scalers permits procedures requiring superior dexterity. DISCUSSION: Breadboard testing of the prototype components has shown spatial resolution of 30 microm, greatly exceeding our expectations. Neurosurgeons will not only be able to perform current procedures with a higher margin of safety but also must speculate on techniques that have hitherto not even been contemplated. This includes coupling the robot to intelligent tools that interrogate tissue before its manipulation and the potential of molecular imaging to transform neurosurgical research into surgical exploration of the cell, not the organ.     

Image guidance: fluoroscopic navigation

Computer-assisted orthopaedic surgery slowly is making its way into routine orthopaedic practice. Orthopaedic trauma has long been identified as a potential impact area of this new technology. Early experience with three-dimensional (3D) image-guided surgery was promising, but this particular technique was limited by the inability to update the 3D computer model in the operating room after fracture reduction maneuvers or implant placement. Virtual fluoroscopy, or fluoroscopic navigation, became available in 1999 and has proven to be a more versatile technology for fracture treatment. Fluoroscopic navigation systems allow the surgeon to store multiple intraoperative fluoroscopic images on a computer workstation; the position of special optically-tracked surgical instruments or implants then may be virtually overlaid onto the stored images in multiple planes during implant placement. The ability to update images after fracture manipulation now has expanded the application of computer-assisted surgery to any procedures that traditionally have relied on intraoperative C-arm use. In selected applications, this technology has been shown to decrease operative time and intraoperative radiation exposure. The advantages of the new technique of fluoroscopic navigation and its current use in trauma applications will be discussed.     

Intraoperative measurement of cortical blood flow adjacent to cerebral AVM using laser Doppler velocimetry

Standard methods for measurement of cerebral blood flow (CBF) are not optimal for continuous intraoperative recording. Laser Doppler velocimetry has been used for evaluation of microcirculatory flow in a variety of human tissues, including skin, muscle, and retina. The authors report the use of this technique for measuring flow in human cerebral cortex. The physiological changes associated with excision of a cerebral arteriovenous malformation are interpreted using CBF recorded intraoperatively with the laser Doppler probe.     

Laser speckle imaging of dynamic changes in flow during photodynamic therapy

We present a study investigating the use of laser speckle imaging (LSI) for monitoring blood flow during photodynamic therapy (PDT) utilizing the therapeutic illumination radiation. The coherent nature of a laser source, often used in PDT, offers the possibility of obtaining information on the blood flow without interrupting treatment. We have found that in the rat skin-fold observation chamber, it is possible to monitor the vasculature response to PDT in individual arteries, veins and in tumour microvasculature with significantly higher spatial and temporal resolution than current methods. This illustrates the potential for LSI for monitoring PDT, in particular for vascular-localizing photosensitizers, where current non-invasive methods are difficult because of high absorption due to blood and the specific localization of photosensitizer within the vasculature. However, critical problems need to be further investigated and solved, like the influence of tissue sampling volume, changing of optical properties and movement artefacts from other vessels on the LSI signal. Until then, the real potential of LSI for monitoring blood flow remains of limited value.     

The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part I-prehistory to 2003

Despite its singular importance, little attention has been given to the neurosurgical operative environment in the scientific and medical literature. This article focuses attention on the development of neurosurgery and the parallel emergence of its operative setting. The operative environment has, to a large extent, defined the "state of the art and science" of neurosurgery, which is now undergoing rapid reinvention. During the course of its initial invention, major milestones in the development of neurosurgery have included the definition of anatomy, consolidation of a scientific basis, and incorporation of the practicalities of anesthesia and antisepsis and later operative technical adjuvants for further refinement of action and minimalism. The progress, previously long and laborious in emergence, is currently undergoing rapid evolution. Throughout its evolution, the discipline has assimilated the most effective tools of modernity into the operative environment, leading eventually to the entity known as the operating room. In the decades leading to the present, progressive minimalization of manipulation and the emergence of more refined operative definition with increasing precision are evident, with concurrent miniaturization of attendant computerized support systems, sensors, robotic interfaces, and imaging devices. These developments over time have led to the invention of neurosurgery and the establishment of the current state-of-the-art neurosurgical operating room as we understand it, and indeed, to a broader definition of the entity itself. To remain current, each neurosurgeon should periodically reconsider his or her personal operative environment and its functional design with reference to modernity of practice as currently defined.     

Intracranial neurosurgery guided by functional imaging

Neurosurgery on eloquent cortex entails important risks of functional deficits complicating aggressive lesion resection. In this study, advanced biomagnetic functional imaging of somatosensory and motor cortex combined with surface rendered magnetic resonance imaging displays including vascular anatomy were used in conjunction with a new nonintrusive intraoperative guided instrumentation system to resect a tumor in eloquent cortex. Intraoperative verification of the accuracy of pre-operative motor localization demonstrated highly accurate results comparing direct stimulation and noninvasive presurgical mapping. The applicability of surface rendered combined functional and anatomic maps of cortex is directly evident on comparison of preoperative computer images and intraoperative pictures. This combination of new technologies has a significant potential for reduced risk and improved outcome in neurosurgery of eloquent cortex.     

Current applications of 3-d intraoperative navigation in craniomaxillofacial surgery: a retrospective clinical review

Intraoperative navigation is a tool that provides surgeons with real-time, interactive access to their patient's diagnostic imaging studies while in the operating room. This modality allows for anatomic localization and facilitates intraoperative planning and diagnosis. The application of intraoperative navigation to neurosurgery, otolaryngology, and orthopedic surgery has been well documented; however, only isolated reports have analyzed its potential in the field of craniomaxillofacial surgery. Advancements in 3-dimensional navigational systems have greatly improved the accuracy of the technology, further broadening its scope. In this article, we evaluate a series of 101 craniomaxillofacial cases in which intraoperative navigation was used. The most common application was for intraorbital cases, such as enophthalmos and acute orbital fracture repairs. Other applications included tumor resection, osteotomy design, pathology localization, and craniotomy design. The major limitations of this technology have been its cost and the fact that it cannot reliably be used for soft-tissue reconstruction currently.     

A frameless, armless navigational system for computer-assisted neurosurgery. Technical note

A computer-assisted neurosurgical navigational system has been developed which displays intraoperative manipulation on the preoperative computerized tomography (CT) scans or magnetic resonance (MR) images. The system consists of a three-dimensional digitizer, a personal computer, and an image-processing unit. Utilizing recently developed magnetic field modulation technology, the three-dimensional digitizer determines the spatial position and orientation angles of the resin probe, triangle-shaped pointer, or suction tube with a small attached magnetic field sensor. Four fiducial markers on the scalp were used to translate the spatial data of the probe onto the preoperative CT scans or MR images of the patient. With this frameless, armless navigational system, CT or MR-imaging stereotaxy can be applied to conventional open neurosurgery without limiting the operative field or interfering with the surgical procedures.     

Anaemia and red blood cell transfusion in intracranial neurosurgery: a comprehensive review

Both anaemia and blood transfusion are associated with poor outcomes in the neurosurgical population. Based on the available literature, the optimal haemoglobin concentration for neurologically injured patients appears to be in the range of 9.0–10.0 g dl^?1, although the individual risks and benefits should be weighed. Several perioperative blood conservation strategies have been used successfully in neurosurgery, including correction of anaemia and coagulopathy, use of antifibrinolytics, and intraoperative cell salvage. Avoidance of non-steroidal anti-inflammatory drugs and starch-containing solutions is recommended given the potential for platelet dysfunction.     

Diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer: Current practice

Nuclear medicine techniques continue to be important non-invasive imaging tools assisting the diagnosis, monitoring and--in some cases--treatment of prostate cancer. Bone scintigraphy was the premier modality to have an extensive role in the staging of prostate cancer and has remained an integral tool for over three decades in the assessment of newly diagnosed disease or in follow-up staging. Therapeutic treatment and palliation of disseminated disease, particularly in the skeleton, has also been successful with several radioisotopes including strontium-89 chloride. Despite advances in nuclear medicine techniques and molecular imaging technology such as positron emission tomography and radioimmunoscintigraphy, bone scintigraphy still remains the gold standard in the assessment of osseous metastatic disease in prostate cancer. Thus, it is important to continually review the modalities that have remained important over time and not just to focus on newer technologies. This article summarizes the current diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer with particular reference to radionuclide bone scintigraphy and positron emission tomography.     

Temporal bone dissection for neurosurgery residents: identifying the essential concepts and fundamental techniques for success

BACKGROUND: Many contemporary neurosurgery residents, cordoned by work hour restrictions and drawn to newer technologies such as endovascular therapy, lack the proper direction necessary to learn the essentials of temporal bone dissection. A thorough knowledge of temporal bone anatomy combined with guidance regarding proper surgical technique makes temporal bone dissection an efficacious and fundamental learning activity. There is currently no concise guide for neurosurgical training programs to use in teaching the essentials of this dissection. METHODS: Over several years, the authors worked with neurosurgery residents to determine the key concepts necessary to gain a fundamental working knowledge of temporal bone dissection. RESULTS: We have identified 5 essential surgical principles and developed a step-by-step dissection technique useful for neurosurgery residents. CONCLUSIONS: Using this template, neurosurgery residents can make the most of their time in the skull base laboratory, becoming familiar with relevant temporal bone anatomy in situ and becoming facile with the surgical techniques necessary for its safe dissection.     

Anesthesia during high-field intraoperative magnetic resonance imaging experience with 80 consecutive cases

Intraoperative magnetic resonance imaging (MRI) has been used for years to update neuronavigation and for intraoperative resection control. For this purpose, low-field (0.1-0.2 T) MR scanners have been installed in the operating room, which, in contrast to machines using higher magnetic field strength, allowed the use of standard anesthetic and surgical equipment. However, these low-field MR systems provided only minor image quality and a limited battery of MR sequences, excluding functional MRI, diffusion-weighted MRI, or MR angiography and spectroscopy. Based on these advantages, a concept using high-field MRI (1.5 T) with intraoperative functional neuronavigational guidance has been developed that required adaptation of the anesthetic regimen to working in the close vicinity to the strong magnetic field. In this paper the authors present their experience with the first 80 consecutive patients who received anesthesia in a specially designed radio frequency-shielded operating room equipped with a high-field (1.5 T) MR scanner. We describe the MR-compatible anesthesia equipment used including ventilator, monitoring, and syringe pumps, which allow standard neuroanesthesia in this new and challenging environment. This equipment provides the use of total intravenous anesthesia with propofol and remifentanil allowing rapid extubation and neurologic examination following surgery. In addition, extended intraoperative monitoring including EEG monitoring required for intracranial surgery is possible. Moreover, problems and dangers related to the effects of the strong magnetic field are discussed.     

Intraoperative digital specimen mammography: prompt image review speeds surgery

Specimen mammograms are often a time-consuming event for image-guided surgery. The use of an intraoperative imaging device may improve the speed of surgery, but comparison must be made to ensure accuracy is maintained. One hundred fifty consecutive image localized patients underwent both intraoperative digital specimen mammogram (in the operating room) and standard specimen mammogram (in radiology). Intraoperative mammograms as read by breast surgeons were as accurate as standard films while saving an average of 19 minutes per operative procedure. Intraoperative digital specimen mammograms can accurately identify target lesions while saving operating room time.     

Potential insights into lower urinary function derived from CNS imaging

Powerful advances in central nervous system (CNS) imaging technology offer an unprecedented opportunity to identify which CNS structures coordinate lower urinary tract (LUT) function in health and disease. Positron emission tomography and functional magnetic resonance imaging studies have already yielded preliminary insights into the neural control of continence mechanisms and their dysfunction. Such technologies have also enabled researchers to begin investigating the changes in CNS activity that occur with age, or after implementation of incontinence therapies, such as sacral neuromodulation. Nonetheless, the use of CNS imaging for understanding LUT function remains in a state of infancy. Several challenges, such as the relative spatial and temporal resolutions of the different technologies, and valid and reliable interpretation of the findings under non‐physiological conditions, limit the ability to constructively understand LUT control. This paper reviews state‐of‐the‐art CNS knowledge, discusses issues related to the use of CNS technology in LUT research, and raises key questions that need to be addressed. Neurourol. Urodynam. 29:629–633, 2010. © 2010 Wiley‐Liss, Inc.     

Optimal surgical care for adolescent idiopathic scoliosis: an international consensus

Purpose

The surgical management of adolescent idiopathic scoliosis (AIS) has seen many developments in the last two decades. Little high-level evidence is available to support these changes and guide treatment. This study aimed to identify optimal operative care for adolescents with AIS curves between 40° and 90° Cobb angle.

Methods

From July 2012 to April 2013, the AOSpine Knowledge Forum Deformity performed a modified Delphi survey where current expert opinion from 48 experienced deformity surgeons, representing 29 diverse countries, was gathered. Four rounds were performed: three web-based surveys and a final face-to-face meeting. Consensus was achieved with ≥70 % agreement. Data were analyzed qualitatively and quantitatively.

Results

Consensus of what constitutes optimal care was reached on greater than 60 aspects including: preoperative radiographs; posterior as opposed to anterior (endoscopic) surgical approaches; use of intraoperative spinal cord monitoring; use of local autologous bone (not iliac crest) for grafts; use of thoracic and lumbar pedicle screws; use of titanium anchor points; implant density of <80 % for 40°–70° curves; and aspects of postoperative care. Variability in practice patterns was found where there was no consensus. In addition, there was consensus on what does not constitute optimal care, including: routine pre- and intraoperative traction; routine anterior release; use of bone morphogenetic proteins; and routine postoperative CT scanning.

Conclusions

International consensus was found on many aspects of what does and does not constitute optimal operative care for adolescents with AIS. In the absence of current high-level evidence, at present, these expert opinion findings will aid health care providers worldwide define appropriate care in their regions. Areas with no consensus provide excellent insight and priorities for future research.     

计算机辅助外科手术的基本概念

目的讨论医用数字影像系统与计算机技术在骨科手术中的应用.方法总结目前计算机技术在骨科临床开发应用的几个组成部分及其应用.结果计算机辅助外科可以:①对患者的数字资料进行采集记录,从术前的CT、MRI和X线片来提取,从术中的X线透视或B超影像获得,从术中手术器械和骨组织上通过三维定位装置得到的定位与定向资料中汲取;②将术前影像资料与术中从解剖标志或从骨表面探取的数据进行配准、整合,或直接利用术中从B超图像截取的骨轮廓影像资料进行手术导航;③帮助医生进行准确的决策过程,采用各种信息,术中针对器械与骨组织的相互位置,在术前或术中的数字影像资料上模拟显示预设导航方案,包括器械的方位、轴线、定向、长度和直径等;④通过被动、主动及半主动系统帮助医生术中监控具体操作,准确地达到术前计划好的方案.结论计算机辅助骨科手术系统可以为术者提供具有安全性与准确性的手术技术,是一种优化手术治疗的步骤.     

Robotics and neurosurgery

Ultimately, neurosurgery performed via a robotic interface will serve to improve the standard of a neurosurgeon's skills, thus making a good surgeon a better surgeon. In fact, computer and robotic instrumentation will become allies to the neurosurgeon through the use of these technologies in training, diagnostic, and surgical events. Nonetheless, these technologies are still in an early stage of development, and each device developed will entail its own set of challenges and limitations for use in clinical settings. The future operating room should be regarded as an integrated information system incorporating robotic surgical navigators and telecontrolled micromanipulators, with the capabilities of all principal neurosurgical concepts, sharing information, and under the control of a single person, the neurosurgeon. The eventual integration of robotic technology into mainstream clinical neurosurgery offers the promise of a future of safer, more accurate, and less invasive surgery that will result in improved patient outcome.     

麻醉保驾护航——让内镜治疗走得更稳更远

近十年来,在麻醉医师的保驾护航下．我国消化内镜技术飞速发展．已成为最常见的侵入性检查方法之一．许多新技术处于国际领先水平。本文从内镜黏膜下剥离术（ESD）和经口内镜下肌层切开术（POEM）这两项新技术的操作方法及麻醉相关问题人手,从术前访视、麻醉选择与术中监护等方面分析了新兴内镜治疗技术的围手术期麻醉管理要点。