Interactive microsurgical anatomy education using photogrammetry 3D models and an augmented reality cube.

OBJECTIVE: This study sought to assess the use of an augmented reality (AR) tool for neurosurgical anatomical education. METHODS: Three-dimensional models were created using advanced photogrammetry and registered onto a handheld AR foam cube imprinted with scannable quick response codes. A perspective analysis of the cube anatomical system was performed by loading a 3D photogrammetry model over a motorized turntable to analyze changes in the surgical window area according to the horizontal rotation. The use of the cube as an intraoperative reference guide for surgical trainees was tested during cadaveric dissection exercises. Neurosurgery trainees from international programs located in Ankara, Turkey; San Salvador, El Salvador; and Moshi, Tanzania, interacted with and assessed the 3D models and AR cube system and then completed a 17-item graded user experience survey. RESULTS: Seven photogrammetry 3D models were created and imported to the cube. Horizontal turntable rotation of the cube translated to measurable and realistic perspective changes in the surgical window area. The combined 3D models and cube system were used to engage trainees during cadaveric dissections, with satisfactory user experience. Thirty-five individuals (20 from Turkey, 10 from El Salvador, and 5 from Tanzania) agreed that the cube system could enhance the learning experience for neurosurgical anatomy. CONCLUSIONS: The AR cube combines tactile and visual sensations with high-resolution 3D models of cadaveric dissections. Inexpensive and lightweight, the cube can be effectively implemented to allow independent co-visualization of anatomical dissection and can potentially supplement neurosurgical education.

Global Neurosurgery: A Retrospective Cohort Study to Compare the Effectiveness of Two Training Methods in Resource-Poor Settings.

BACKGROUND AND OBJECTIVES: Many low- and middle-income countries are experiencing profound health care workforce shortages. Surgical subspecialists generally practice in large urban centers but are in high demand in rural areas. These subspecialists must be trained through sustainable programs to address this disparity. We quantitatively compared the relative effectiveness of 2 unique training models to advance neurosurgical skills in resource-poor settings where formally trained neurosurgeons are unavailable. METHODS: Neurosurgical procedure data were collected from 2 hospitals in Tanzania (Haydom Lutheran Hospital [HLH] and Bugando Medical Centre [BMC]), where 2 distinct training models ("Train Forward" and "Back-to-Back," respectively) were incorporated between 2005 and 2012. RESULTS: The most common procedures performed were ventriculoperitoneal shunt (BMC: 559, HLH: 72), spina bifida repair (BMC: 187, HLH: 54), craniotomy (BMC: 61, HLH: 19), bone elevation (BMC: 42, HLH: 32), and craniotomy and evacuation (BMC: 18, HLH: 34). The number of annual procedures at BMC increased from 148 in 2008 to 357 in 2012; at HLH, they increased from 18 in 2005 to 80 in 2010. Postoperative complications over time decreased or did not significantly change at both sites as the diversity of procedures increased. CONCLUSION: The Train Forward and Back-to-Back training models were associated with increased surgical volume and complexity without increased complications. However, only the Train Forward model resulted in local, autonomous training of surgical subspecialists after completion of the initial training period. Incorporating the Train Forward method into existing training programs in low- and middle-income countries may provide unique benefits over historic training practices.

A New Source of Nonprofit Neurosurgical Funding.

The purpose of this paper is to propose and qualify a novel funding mechanism for international neurosurgical nonprofits. The article first identifies and explains neurosurgeons' means for practicing in the developing world through a literature review. After this examination of the current funding methods for surgical care in low-income regions, the work transitions to an explanation of the applications and limitations of a new resource: the internal wealth of a developing country. This wealth may be leveraged by way of a for-profit hospital to create sustainable and domestic funding for nonprofit neurosurgical training. The applicability of the proposed mechanism extends beyond the field of neurosurgery to nonprofits in any health-related discipline. Factors influencing the viability of this mechanism (including local disease burden, economic trajectory, and political stability) are examined to create a baseline set of conditions for success.

Isolated left homonymous hemianopia secondary to a pericatheter cyst-a rare presentation of a ventriculoperitoneal shunt failure.

A 26-year-old woman developed a left homonymous hemianopia 1 week after placement of a ventriculoperitoneal shunt through a right parieto-occipital approach. Computed tomography demonstrated a parenchymal cyst in the right occipital lobe. After shunt revision, there was concomitant resolution of the cyst and visual field defect over 1 month. The literature is reviewed regarding this unusual complication of ventriculoperitoneal shunt failure.

Neurosurgical capacity building in the developing world through focused training.

OBJECT: In Tanzania, there are 4 neurosurgeons for a population of 46 million. To address this critical shortage of neurosurgical care, the authors worked with local Tanzanian health care workers, neurosurgeons, the Ministry of Health and Social Welfare, and the Office of the President of Tanzania to develop a train-forward method for sustainable, self-propagating basic and emergency neurosurgery in resource-poor settings. The goal of this study was to assess the safety and effectiveness of this method over a 6-year period. METHODS: The training method utilizes a hands-on bedside teaching technique and was introduced in 2006 at a remote rural hospital in northern Tanzania. Local health care workers were trained to perform basic and emergency neurosurgical procedures independently and then were taught to train others. Outcome information was retrospectively collected from hospital records for the period from 2005 (1 year before method implementation) through 2010. Analysis of de-identified data included descriptive statistics and multivariable assessment of independent predictors of complications following a patient's first neurosurgical procedure. RESULTS: By 2010, the initial Tanzanian trainee had trained a second Tanzanian health care worker, who in turn had trained a third. The number of neurosurgical procedures performed increased from 18 in 2005 to an average of 92 per year in the last 3 years of the study period. Additionally, the number of neurosurgical cases performed independently by Tanzanian health care providers increased significantly from 44% in 2005 to 86% in 2010 (p < 0.001), with the number of complex cases independently performed also increasing over the same time period from 34% to 83% (p < 0.001). Multivariable analysis of clinical patient outcome information to assess safety indicated that postoperative complications decreased significantly from 2005 through 2010, with patients who had been admitted as training progressed being 29% less likely to have postoperative complications (OR 0.71, 95% CI 0.52-0.96, p = 0.03). CONCLUSIONS: The Madaktari Africa train-forward method is a reasonable and sustainable approach to improving specialized care in a resource-poor setting.

Multi-institutional neurosurgical training initiative at a tertiary referral center in Mwanza, Tanzania: where we are after 2 years.

BACKGROUND: The paucity of neurosurgical care in East Africa remains largely unaddressed. A sustained investment in local health infrastructures and staff training is needed to create an independent surgical capacity. The Madaktari organization has addressed this issue by starting initiatives to train local general surgeons and assistant medical officers in basic neurosurgical procedures. We report illustrative cases since beginning of the program in Mwanza in 2009 and focus on the most recent training period. METHODS: A multi-institutional neurosurgical training program and a surgical database was created at a tertiary referral center in Mwanza, Tanzania. We collected clinical data on consecutive patients who underwent a neurosurgical procedure between September 9th and December 1st, 2011. All procedures were performed by a local surgeon under the supervision of a visiting neurosurgeon. Since the inception of the training initiative, comprehensive multidisciplinary training courses in Tanzania and an annual visiting fellowship for East African surgeons to travel to a major U.S. medical center have been established. RESULTS: At initial visits infrastructure and feasibility of complex case scenarios was assessed. Surgeries for brain tumors and complex spinal cases were performed. During the 3-month training period, 62 patients underwent surgery. Pediatric hydrocephalus comprised 52% of patients, 11% suffered from meningomyelocelia, and 6% presented with an encephalocele. A total of 24% of patients were treated for trauma-related conditions, representing 75% of the adult patients. A total of 10% of patients had surgery because of traumatic spine injury, and 15% of operations were on patients with severe head injury. A total of 6% of patients presented with degenerative spine disease. One patient sustained a fatal perioperative complication. At the end of the training period, the local general surgeon was able to perform all basic neurosurgical cases independently. CONCLUSIONS: Neurosurgical care in Tanzania needs to address a diverse, unique disease burden. We found that local surgeons could be enabled to safely perform basic cranial and spinal neurosurgical procedures through immersive, 1-on-1 on-site collaborations, multidisciplinary courses, and educational visiting fellowships.

The use of IV-tubing as a closed-suction drainage system during neurosurgical cases in Tanzania.

BACKGROUND: Commercial closed-suctions drainage systems are commonly used in the United States and many other countries for use in neurosurgical cases. However, in Tanzania and other developing nations with fewer resources, these are not available. This report explores another option for a closed-system drainage system utilizing inexpensive supplies found commonly in hospitals around the world. METHODS: Sterile IV-tubing is cut, inserted into the wound, and brought out through an adjacent puncture incision. For suction, an empty plastic bottle can be attached to the tubing. RESULTS: The IV-tubing closed-suction drainage system was applied in both cranial and spinal neurosurgical procedures, including as subdural, subgaleal, epidural, and suprafacial drains. It maintained suction and was an adequate substitute when commercial drains are unavailable. CONCLUSIONS: This report illustrates how sterile IV-tubing can be adapted for use as a closed-drainage system. It utilizes inexpensive supplies commonly found in many hospitals throughout the world and can be applied to both cranial and spinal neurosurgical procedures.

Brain surgery in the bush: adapting techniques and technology to fit the developing world.

The critical shortage of surgical services in many areas of the world has profound effects on local communities. Approximately 11% of global disease burden can be attributed to causes that are surgically treatable. Efforts have been made to recruit professionals from developed nations to compensate for the lack of such expertise. However, this practice has created a cycle of dependency on foreign-trained physicians and the medical tools they bring. Recognition of this problem calls for adaptation of a novel problem-solving approach. This article describes techniques and technology available in east Africa that have been adapted to allow basic and emergency neurosurgery to be performed in the absence of complex medical infrastructure and equipment. Commonplace items found in the local environment can be used to emulate more sophisticated instruments, and community-specific engineering programs can be developed to provide locally produced appropriate technology that promotes independence from Western sources. The local economy benefits from much-needed stimulation when these tools are created locally, and this allows for readily available replacement and repair. More studies are under way to identify problems and implement interventions that are realistic and appropriate for these populations.

Rapid ventricular pacing: a novel technique to decrease cardiac output for giant basilar aneurysm surgery.

A case of a 49 year old man with a giant basilar artery aneurysm requiring rapid ventricular pacing is presented. Rapid ventricular pacing decreased aneurysm size and increased operative exposure, which aided surgical decision making. It also provided decreased wall tension in the aneurysm.

Neurosurgery in Tanzania: a discussion of culture, socioeconomics, and humanitarians.

OBJECTIVE: To elucidate the progress of neurosurgical practices in Tanzania, taking into account humanitarian, socioeconomic, and geographic influences. METHOD: Articles, records, and historical texts were consulted to establish a timeline and history of neurosurgery in Tanzania. RESULTS: Reulen, a German neurosurgeon, was integral to the development of sustainable neurosurgical services in Tanzania. By training Tanzanians who returned to their country to practice, Reulen helped to establish a continuity of care and legacy on which future Tanzanian surgeons could build. Subsequently, as neurosurgical services were integrated into the Muhimbili Orthopedic Institute, surgeons found a hospital to call home and a place to focus their efforts. Neurosurgical services have now been offered to the Tanzanian people for >40 years, a direct consequence of international influences coupled with certain extraordinary Tanzanian physicians. CONCLUSIONS: Neurosurgery in Tanzania and Africa more generally has a long history; however, it was not until more recent efforts of certain local pioneers and educational advisors abroad that modernization occurred. The progress of the past 50 years is substantial and with continued efforts advances will continue to be made.

History and current state of neurosurgery at the Medical University of South Carolina.

We review the development of neurosurgery at the Medical University of South Carolina (MUSC) and the emergence of MUSC as a leading academic neurosurgical center in South Carolina. Historical records from the Waring Historical Library were studied, former and current faculty members were interviewed, and the personal records of Dr Phanor J Perot were examined. Dr Frederick E Kredel was the first to perform cerebral revascularization in stroke patients using omental flaps and the first to culture glioma cells in artificial media. The MUSC Neurosurgery residency program was established in 1964 by its first formally trained neurosurgeon, Julian Youmans, MD. The first graduate of the program, Dr Russell Travis, went on to become the President of the American Association of Neurological Surgeons. In 1968, the longest serving chairman, Dr Perot, joined the department and conducted significant research in spinal cord injury, receiving a continuous, 20-year award from the National Institute of Neurological Disorders and Stroke. A major change in the neurosurgery program occurred in 2004 when Dr Sunil Patel accepted the chairmanship. He integrated neurosurgery, neurology, and basic neuroscience departments into a comprehensive Department of Neurosciences to provide integrated clinical care. This department now ranks second in the country in National Institutes of Health research funding. Recently, the Center for Global Health and Global Neurosurgery was established with a vision of caring for patients beyond national borders. Neurosurgery at MUSC has been influenced by Drs Kredel and Perot and the current leadership is moving forward with a uniquely integrated department with novel areas such as global neurosurgery.

Temporal characterization of the functional density of the vasa vasorum by contrast-enhanced ultrasonography maximum intensity projection imaging.

OBJECTIVES: We sought to determine whether contrast-enhanced ultrasound (CEU) microangiography with maximum intensity projection (MIP) processing could temporally evaluate proliferation of the vasa vasorum (VV) in a model of mural hemorrhage. BACKGROUND: Expansion of the VV and plaque neovascularization contributes to plaque growth and instability and may be triggered by a variety of stimuli, including vascular hemorrhage. However, quantitative in vivo methods for temporal assessment of VV remodeling are lacking. METHODS: In 24 rabbits fed a high-fat diet, either autologous whole blood or saline was percutaneously injected into the media-adventitia of the femoral artery using ultrahigh-frequency ultrasound guidance. Functional VV density at the injection site and contralateral control artery was assessed 1, 2, and 6 weeks after injection with CEU imaging with MIP processing. In vitro studies with renathane microtubes were also performed to validate linear density measurement with CEU and MIP processing. RESULTS: In vitro studies demonstrated that MIP processing of CEU data reflected the relative linear density of vessels in a manner that was relatively independent of contrast concentration or microtube flow rate. On CEU with MIP, there was a 3-fold increase in femoral artery VV microvascular density at 1 and 2 weeks after blood injection (p < 0.01 vs. contralateral control), whereas VV density increased minimally after saline injection. At 6 weeks, VV vascular density decreased in blood-treated vessels and was not different from saline-injected or contralateral control vessels. CONCLUSIONS: CEU with MIP processing can provide quantitative data on temporal changes in the functional density of the VV. This method may be useful for evaluating high-risk features of plaque neovascularization or response to therapies aimed at plaque neovessels.

Initial audit of a basic and emergency neurosurgical training program in rural Tanzania.

OBJECTIVE: As of 2006, only three formally trained neurosurgeons are licensed in Tanzania. Recently, efforts have increased toward training local Tanzanian physicians and assistant medical officers (AMOs) to meet the basic neurosurgical needs of nonurban areas. Between January and July 2006, an initial attempt at such an apprenticeship was undertaken with a locally trained AMO already performing general surgery at Haydom Lutheran Hospital, Tanzania. METHODS: Fifty-one neurosurgical patients were identified and their patient charts were requested from the medical records office. Records were not available for 4 of the 51 patients for undeterminable reasons. RESULTS: The neurosurgical infrastructure at HLH is basic but adequate for a number of procedures. Cases performed included ventriculoperitoneal shunts, repair of myelomeningoceles, and burr holes and craniotomies for trauma and biopsies. Of 51 patients initially identified, 14 (27%) were confirmed deceased and 20 (39%) confirmed living. The remaining 17 (33%) were lost to follow-up. There were no significant differences in the mortality rates of patients receiving care from the American-trained neurosurgeon and those receiving care from the Tanzanian AMO trained and mentored by the American neurosurgeon. CONCLUSIONS: This initial audit provides support for the development of limited neurosurgery programs in underserved communities. Combined utilization of available neurosurgeons and continued training for available local clinicians may help to meet this need.

The role of surgery for high-grade intracranial dural arteriovenous fistulas: importance of obliteration of venous outflow.

OBJECT: Surgical intervention may be required if endovascular embolization is insufficient to completely obliterate intracranial dural arteriovenous fistulas (DAVFs). The authors report their 14-year experience with 23 patients harboring diverse intracranial DAVFs that required surgical intervention. METHODS: Between 1993 and 2007, 23 patients underwent surgery for intracranial DAVFs. The following types of DAVFs were treated: superior petrosal sinus (in 10 patients); parietooccipital (in 3); confluence of sinuses and ethmoidal (in 2 each); and tentorial, falcine, occipital, transverse-sigmoid, superior sagittal, and cavernous sinuses (in 1 patient each). In all cases, the authors' goal was to obliterate the DAVF venous outflow by direct surgical interruption of the leptomeningeal venous drainage. Transarterial embolization was used primarily as an adjunct to decrease flow to the DAVF prior to definitive treatment. RESULTS: Complete angiographic obliteration of the DAVF was achieved in all cases. There were no complications of venous hypertension, venous infarction, or perioperative death. There were no recurrences and no further clinical events (new hemorrhages or focal neurological deficits) after a mean follow-up of 45 months. CONCLUSIONS: The authors' experience emphasizes the importance of occluding venous outflow to obliterate intracranial DAVFs. Those that drain purely through leptomeningeal veins can be safely obliterated by surgically clipping the arterialized draining vein as it exits the dura. Radical excision of the fistula is not necessary.

Contrast ultrasonographic assessment of cerebral perfusion in patients undergoing decompressive craniectomy for traumatic brain injury.

OBJECT: The aims of this study were to determine whether contrast-enhanced ultrasonography (CEU) could be used for noninvasive evaluation of cerebral perfusion in patients with traumatic brain injury (TBI) and to assess the effect of decompressive surgery on cerebral perfusion as measured by CEU. METHODS: Contrast-enhanced ultrasonography with intravenous administration of a microbubble contrast agent was performed in six patients with TBI undergoing decompressive craniectomy. Contrast-enhanced ultrasonography was performed through a bur hole before craniectomy and through the calvarial defect immediately after craniectomy and on postoperative Days 1 and 2. For the latter two studies, patients were placed in the recumbent position and at a 35 degrees incline to investigate changes in perfusion produced by modulation of intracranial pressure (ICP). Cerebral microvascular blood flow increased by almost threefold immediately after craniectomy, from a mean of 7.5 +/- 6.9 (standard deviation [SD]) to 20.9 +/- 11.6 (p < 0.05), and further improved on postoperative Day 1 (mean 37.1 +/- 13.9 [SD], p < 0.05, compared with postcraniectomy microvascular blood flow) without subsequent change on Day 2. The change in microvascular perfusion correlated inversely with the initial ICP (p < 0.01), indicating less recovery of flow when preoperative ICP was markedly elevated. On postoperative Days 1 and 2, head-of-bed elevation produced an increase in microvascular perfusion on CEU (mean 37 +/- 11 compared with 51 +/- 20, p < 0.05) and a small decrease in ICP (mean 16 +/- 5 mm Hg compared with 12 +/- 4 mm Hg, p < 0.05). In patients with parenchymal hematoma, CEU provided spatial information on perfusion abnormalities in the hemorrhagic core and surrounding tissues. CONCLUSIONS: Contrast-enhanced ultrasonography has potential for the intraoperative and bedside assessment of cerebral perfusion in patients with TBI. The technique may be appropriate for evaluating responses to therapies aimed at preventing secondary ischemia and for assessing regional perfusion abnormalities.

Principles of cerebral oxygenation and blood flow in the neurological critical care unit.

Cerebrovascular disease and trauma are leading causes of death in the United States. In addition to the initial insult to the brain, disturbances of cerebral oxygenation and metabolism underlie many of the secondary pathophysiological processes that increase both morbidity and mortality. Therefore, researchers and clinicians have sought to obtain a more thorough understanding of the physiological and biochemical principles of cerebral oxygenation and metabolism. New technologies capable of offering continuous and quantitative assessment of cerebral oxygenation may improve clinical outcomes. In this article, we review the physiological principles of cerebral metabolism, cerebral blood flow and their metabolic coupling, and cerebral oxygenation, with particular emphasis on variables that could be monitored and managed in an intensive care unit setting.

Neuromonitoring in neurological critical care.

In this article, we review technologies available for direct monitoring of cerebral oxygenation and metabolic status, including jugular venous oxygen saturation, brain tissue oxygen tension, transcranial cerebral oximetry with near-infrared spectroscopy, Positron emission tomography oxidative metabolism, single-photon emission computed tomography/computed tomography perfusion and functional imaging, and cerebral metabolite measurement using microdialysis. We also introduce a novel method of monitoring cerebral perfusion that may substitute for direct monitoring of oxygenation in the future.