Early Effects of COVID-19 Pandemic on Neurosurgical Training in the United States: A Case Volume Analysis of 8 Programs.

OBJECTIVE: To determine the impact of the 2019 novel coronavirus disease (COVID-19) pandemic on operative case volume in 8 U.S. neurosurgical residency training programs in early 2020 and to survey these programs regarding training activities during this period. METHODS: A retrospective review was conducted of monthly operative case volumes and types for 8 residency programs for 2019 and January through April 2020. Cases were grouped as elective cranial, elective spine, and nonelective emergent cases. Programs were surveyed regarding residents' perceptions of the impact of COVID-19 on surgical training, didactics, and research participation. Data were analyzed for individual programs and pooled across programs. RESULTS: Across programs, the 2019 monthly mean ± SD case volume was 211 ± 82; 2020 mean ± SD case volumes for January, February, March, and April were 228 ± 93, 214 ± 84, 180 ± 73, and 107 ± 45. Compared with 2019, March and April 2020 mean cases declined 15% (P = 0.003) and 49% (P = 0.002), respectively. COVID-19 affected surgical case volume for all programs; 75% reported didactics negatively affected, and 90% reported COVID-19 resulted in increased research time. Several neurosurgery residents required COVID-19 testing; however, to our knowledge, only 1 resident from the participating programs tested positive. CONCLUSIONS: This study documents a significant reduction in operative volume in 8 neurosurgery residency training programs in early 2020. During this time, neurosurgery residents engaged in online didactics and research-related activities, reporting increased research productivity. Residency programs should collect data to determine the educational impact of the COVID-19 pandemic on residents' operative case volumes, identify deficiencies, and develop plans to mitigate any effects.

A Novel Plate-Based System (UNIMAX) for Posterior Instrumented Spinal Fusion.

Introduction The polyaxial head pedicle screw-rod system is a commonly used spinal instrumentation technique to achieve stabilization, deformity correction, and bony fusion. We present a novel plate-based pedicle screw system (UNIMAXTM) that can be used for multi-level instrumentation with potential advantages for selected applications. Methods Bilateral titanium monoaxial pedicle screws are linked at each level by robust transversely oriented cross plates forming ring constructs capable of rigid triangulation at each level. The cross plates are then interconnected by sagittally oriented rigid plates situated medial to the screw heads. Biomechanically, the construct was tested for quasi-static torsion and fatigue in axial compression. The system is approved by the Food and Drug Administration (FDA). The system and case examples are presented showing its potential advantages. Results The quasi-static torsion, the mean for the angular displacement, torsional stiffness, and torsional ultimate strength was 2.5 degrees (SD ± 0.8), 5.3 N-m/mm (SD ± 0.7), and 21.6 N-m (SD ± 4.4). For the fatigue in axial compression, the closed ring construct failed when the applied load and bending moment were ≥ 1500 N and ≥ 60 N.m. This system maximizes the construct rigidity, allows easy extension to adjacent levels, and can be incorporated intuitively into practice. The ring construct with triangulation at each level, together with its biomechanical robustness, predicts a high pullout resistance. It requires an open posterior approach incompatible with minimally invasive techniques. Conclusion This system may have advantages over the screw-rod systems in carefully selected situations requiring extra rigidity and high pull-out strength for complex reconstructions, sagittal and/or coronal correction, patients with poor bone quality, revisions, and/or extension to adjacent levels.

Spinal Cord Stimulation for Visceral Pain: Present Approaches and Future Strategies.

INTRODUCTION: The introduction of successful neuromodulation strategies for managing chronic visceral pain lag behind what is now treatment of choice in refractory chronic back and extremity pain for many providers in the United States and Europe. Changes in public policy and monetary support to identify nonopioid treatments for chronic pain have sparked interest in alternative options. In this review, we discuss the scope of spinal cord stimulation (SCS) for visceral pain, its limitations, and the potential role for new intradural devices of the type that we are developing in our laboratories, which may be able to overcome existing challenges. METHODS: A review of the available literature relevant to this topic was performed, with particular focus on the pertinent neuroanatomy and uses of spinal cord stimulation systems in the treatment of malignant and nonmalignant gastrointestinal, genitourinary, and chronic pelvic pain. RESULTS: To date, there have been multiple off-label reports testing SCS for refractory gastrointestinal and genitourinary conditions. Though some findings have been favorable for these organs and systems, there is insufficient evidence to make this practice routine. The unique configuration and layout of the pelvic pain pathways may not be ideally treated using traditional SCS implantation techniques, and intradural stimulation may be a viable alternative. CONCLUSIONS: Despite the prevalence of visceral pain, the application of neuromodulation therapies, a standard approach for other painful conditions, has received far too little attention, despite promising outcomes from uncontrolled trials. Detailed descriptions of visceral pain pathways may offer several clues that could be used to implement devices tailored to this unique anatomy.

Intraoperative CT for Neuronavigation Guidance and Confirmation of Foramen Ovale Cannulation for Glycerol Trigeminal Rhizotomy: A Technical Report and Case Series.

Glycerol rhizotomy was originally described as an initial surgical treatment for trigeminal neuralgia after the failure of medical therapy. Here we describe its use as a salvage procedure, typically after failure of multiple other modalities including microvascular decompression, stereotactic radiosurgery, and/or other percutaneous procedures. Foramen ovale cannulation as a "salvage procedure" may be complicated by lack of cerebrospinal fluid (CSF) return despite adequate cannulation of the foramen ovale, making conventional fluoroscopic confirmation of adequate needle placement less certain. In this article, we describe the application of intraoperative CT, fused with high-resolution preoperative CT/MRI for neuronavigation to accurately cannulate the foramen ovale and Meckel's cave for glycerol rhizotomy. Intraoperative CT, again fused with high-resolution preoperative CT and MRI studies, was then used to confirm accurate trajectory through the foramen ovale and the adequate location of the needle tip in Meckel's cave before injecting glycerol. We present our initial experience with 14 patients who underwent glycerol rhizotomy by these techniques depending on intraoperative CT. It appears that intraoperative CT-guided neuronavigation provides a practical, reliable, and accurate route to the foramen ovale and aids in the confirmation of adequate needle placement even when there is a lack of CSF return. These methods may be especially useful for difficult cannulations typical in salvage procedures. In an era of feasible intraoperative guidance, with advanced stereotactic planning software allowing the fusion of intraoperative CT with high-resolution preoperative CT and MRI datasets, these techniques can be applied to foramen ovale cannulation for glycerol rhizotomy without major modification.

Pseudoanginal chest pain associated with vagal nerve stimulation: a case report.

BACKGROUND: Vagal nerve stimulation (VNS) can be an effective therapy for patients with epilepsy refractory to anti-epileptic drugs or intracranial surgery. While generally well tolerated, it has been associated with laryngospasm, hoarseness, coughing, dyspnea, throat and atypical chest pain, cardiac symptoms such as bradycardia and occasionally asystole. We report on a patient receiving vagal nerve stimulation who experienced severe typical anginal chest pain during VNS firing without any evidence of cardiac ischemia or dysfunction. Thus, the pain appeared to be neuropathic from the stimulation itself rather than nociceptive secondary to an effect on heart function. CASE PRESENTATION: A 29-year-old man, with a history of intractable frontal lobe epilepsy refractory to seven anti-epileptic medications and subsequent intracranial surgery, underwent VNS implantation without complications. On beginning stimulation, he began to have intermittent chest pain that corresponded temporally to his intermittent VNS firing. The description of his pain was pathognomonic of ischemic cardiac chest pain. On initial evaluation, he displayed Levine's sign and reported crushing substernal chest pain radiating to the left arm, as well as shortness of breath walking upstairs that improved with rest. He underwent an extensive cardiac workup, including 12-lead ECG, cardiac stress test, echocardiogram, 12-day ambulatory cardiac monitoring, and continuous ECG monitoring each with and without stimulation of his device. The workup was consistently negative. Inability to resolve the pain necessitated the disabling and eventual removal of the device. CONCLUSION: To our knowledge, this is the first report of pseudoanginal chest pain associated with VNS. This occurrence prompted our review of the mechanisms of cardiac chest pain and suggests that vagal afferents may convey anginal pain separately or in parallel with known spinal cord pain mechanisms. These insights into the physiology of chest pain may be of general interest and important to surgeons implanting VNS devices who may potentially encounter such symptoms.

Punctate Midline Myelotomy for Chronic, Intractable, Non-malignant Visceral Pain: A Case Report.

Punctate midline myelotomy (PMM) has a strong anatomic and functional basis for its role in the treatment of visceral pain. The procedure derived from advances in the understanding of the postsynaptic dorsal column (PSDC) pathway and the converging laboratory and clinical evidence that this spinal cord pathway plays a dominant role in conveying visceral pain to higher levels of the nervous system. The result of PMM is a concise, effective interruption of the PSDC pathway with minimal to no side effects. While considerable evidence now documents that PMM has good efficacy and safety in treating malignant visceral pain, there is little experience describing its application to chronic severe refractory visceral pain of benign origin.  We present the case of a patient with a 13-year history of severe non-malignant chronic abdominal visceral pain who obtained complete pain relief from a PMM at the T7 level. Intraoperative somatosensory evoked potential (SSEP) monitoring did not show changes after making the PMM lesion. As of six-months postoperative follow-up, the benefit shows no sign of fading, all pain medications have been discontinued, and there has been no impairment of motor function, bowel or bladder function, sexual function, gait or station. Upon detailed questioning, the patient endorsed only mild subjective reduced sensation of the inner aspects of her feet that was not bothersome to her. On detailed testing, position sense was preserved throughout; the Romberg test was negative, and the only finding was reduced vibratory sensation over the great toe pads. We cautiously suggest that the PMM operation may allow relief from severe, intractable, benign visceral pain syndromes for which effective treatments are otherwise elusive. The procedure warrants further study for such conditions.

Multiple Recurrences of Trigeminal Neuralgia Caused by Deformation of the Trigeminal Nerve.

Microvascular decompression (MVD) is frequently used for the treatment of trigeminal neuralgia (TN). We present a case of TN with multiple recurrences despite different interventions. A 50-year-old patient presented with a five-year history of left TN. He initially had an MVD with Teflon padding that eliminated his pain for a year. When pain recurred, he went on to stereotactic radiosurgery, which did not help. He then had two percutaneous retrogasserian glycerol injections, the first one relieved pain for a year and the second only six months. After the second recurrence, we repeated the magnetic resonance imaging (MRI) of the brain, and it showed kinking of the nerve with the padding in place. We decided to re-explore the nerve based on the MRI findings. Intraoperatively, we observed the Teflon padding had become adherent to the petrous bone which caused deformation of the nerve. We did adhesiolysis with debulking of the padding, following which the nerve appeared more relaxed. Postoperatively, the patient had immediate resolution of his pain. At eight-month follow-up, the patient remained pain-free. Multiple factors can be involved in recurrence of TN after MVD. In this case, the size of the padding, continued distortion from the offending artery in addition to scarring from radiosurgery may have contributed to the deformation of the nerve and the recurrence of symptoms. A new MRI can be beneficial when the neuralgia symptoms recur in delayed fashion after successful MVD. Also, the use of a more compact padding material, like Gore-Tex, may cause less deformation of the nerve.

Punctate Midline Myelotomy Reduces Pain Responses in a Rat Model of Lumbar Spine Pain: Evidence that the Postsynaptic Dorsal Column Pathway Conveys Pain from the Axial Spine.

Punctate midline myelotomy (PMM) has been successfully applied clinically in humans for the relief of intractable visceral pain. The operation is thought to work by interrupting the postsynaptic dorsal column pathway (PSDC) of the spinal cord. In fact, PMM was developed specifically for that purpose after it was demonstrated in rats that the PSDC conveyed about 90% of the visceral pain information to the thalamus. The application of PMM also to the problem of severe intractable back or spine pain was never tested, and it has never been established whether the PSDC pathway relates only to visceral pain or whether there may be a broader involvement with pain affecting structures of embryological midline origin, perhaps including the spine. Retrospective analyses of decades of results from various attempted myelotomy procedures in man for the relief of pain are consistent with the notion that the common element crucial to the successful midline or visceral pain relief was the interruption--even incomplete--of the PSDC pathway. Herein, we present evidence from a rat model of lumbar facet pain that interruption of the PSDC significantly reduces pain responses. The implications for the possible treatment of severe intractable spine pain in man are discussed.

Neuronavigation-guided endoscopic decompression of superior orbital fissure fracture: case report and literature review.

OBJECTIVE: We present a rare case of an isolated superior orbital fissure fracture resulting from blunt injury to the face and presenting with selective cranial nerve deficits surgically treated with a neuroendoscopic approach. The anatomy of the superior orbital fissure is detailed, and the peculiarities of the surgical approach described. METHOD: A review of the existing literature reveals this is the first reported case of a neuronavigation-assisted endoscopic approach used in the extraction of a superior orbital fracture fragment with good outcome. Current guidelines for an endoscopic approach in orbital trauma are reviewed, and pertinent literature is discussed. CONCLUSION: Neuronavigation-assisted decompression should be considered as an effective means of removing superior orbital fissure fractures.

Coexistent intraventricular abnormalities in periventricular giant arachnoid cysts.

OBJECT: Arachnoid cysts are congenital lesions that arise during development by splitting of the arachnoid membrane. Large cysts can be adjacent to CSF pathways causing a marked midline shift and hydrocephalus. The association between a large arachnoid cyst and hydrocephalus has been commonly described as being due to a mass effect, but these previous reports have not focused closely on any associated intraventricular abnormalities. METHODS: Seven patients who were previously treated with a cystoperitoneal shunt presented with shunt failure, hydrocephalus, and/or cyst expansion. All of these patients had giant arachnoid cysts extending to the periventricular region from the original site, which was the sylvian fissure in 4 patients, and the suprasellar cistern, quadrigeminal cistern, and interhemispheric fissure in 1 patient each. Endoscopic exploration of the ventricular system and cyst fenestration was then performed in all patients. RESULTS: The endoscopic findings were obstruction of the cerebral aqueduct by a membrane not related to the cyst in 5 patients, occlusion of the foramen of Monro in 6, septum pellucidum hypoplasia in 2, and occlusion of the cerebral aqueduct by a quadrigeminal arachnoid cyst in 1. Endoscopic procedures performed were septum pellucidum fenestration and/or foraminoplasty in 5 patients, aqueductoplasty in 2, endoscopic third ventriculostomy in 5, fenestration of the lamina terminalis in 1, and direct cystocisternostomy in 1. After the endoscopic procedure, signs and symptoms of increased intracranial pressure and hydrocephalus improved in all patients, with a reduction in size of the cyst and the ventricle. CONCLUSIONS: Ventricular abnormalities contributing to hydrocephalus may be associated with arachnoid cysts. These abnormalities may more likely reflect a common origin than a casual relation. Foramen of Monro stenosis and cerebral aqueduct occlusion associated with an arachnoid cyst can be more frequent than has been previously believed. In cases of periventricular giant arachnoid cysts, endoscopic exploration is a good alternative for examining the ventricular system and identifying and treating CSF obstructions caused by and/or related to arachnoid cysts.

Apnea and macrocephaly-cutis marmorata telangiectatica congenita.

The authors report a case of an infant girl with macrocephaly-cutis marmorata telangiectatica congenita (Macrocephaly-CMTC). This patient presented with developmental delay, mild subcostal retractions, and occasional apneic spells. An MRI demonstrated mild to moderate lateral ventricle hydrocephalus, left hemi-megalencephaly, and left cerebellar tonsillar herniation with full occlusion of the cisterna magna. Her foramen magnum was narrowed, measuring 17.5mm in transverse diameter. This value was significantly below the 50th percentile for age, which is 23.5mm. Together, these findings were suggestive of cervicomedullary cord compression, concerning for sudden death. The patient underwent posterior fossa decompression by suboccipital craniectomy and cervical laminectomy. Initially due to hypertrophy and paralysis of the left true and false vocal cords, endotracheal intubation was not achieved, requiring tracheostomy tube placement. To our knowledge this is the first report of apnea in a patient diagnosed with M-CMTC, likely due to cervicomedullary cord compression and perhaps exacerbated by unilateral laryngeal hypertrophy. M-CMTC is a newly-described hemi-hypertrophy syndrome affecting the neurodevelopment of affected children. The authors emphasize airway obstruction secondary to unilateral hypertrophy of the vocal cords in addition to brainstem compromise as a consideration for the etiology of apnea in M-CMTC patients presenting with signs and symptoms of cervicomedullary cord compression.

A new technique allowing prolonged temporary cerebral artery occlusion.

OBJECT: Clipping of complex cerebral aneurysms often requires temporary vessel occlusion. The risk of stroke, however, increases exponentially with occlusion time. The authors hypothesized that prolonged temporary occlusion might be tolerated if the occluded vessels were perfused with cold physiological saline solution (CPSS). A low-flow perfusion rate would permit surgical manipulation of an aneurysm distal to the occlusion. METHODS: To test this hypothesis, the authors temporarily occluded the middle cerebral artery (MCA) with an endovascular catheter in 6 rats. Three animals, the treatment group, were perfused with 5-ml CPSS/hour through the occluding endovascular catheter into the MCA, and the other 3 served as an ischemic control group. In both groups, the catheter was removed after 90 minutes of occlusion. The brain temperature was monitored with a stereotactically placed probe in the caudate-putamen in 2 separate experimental groups (11 animals). RESULTS: Magnetic resonance imaging perfusion scanning during vessel occlusion confirmed similar reduction of cerebral blood flow during MCA occlusion in both the simple-occlusion and perfusion-occlusion groups. Magnetic resonance imaging diffusion scans performed 24 hours after temporary occlusion revealed infarcts in the ischemic control group of 138.3 +/- 28.0 mm(3) versus 9.9 +/- 9.9 mm(3) in the cold saline group (p < 0.005). A focal cooling effect during perfusion with CPSS was demonstrated (p < 0.05). CONCLUSIONS: Prolonged temporary cerebral vessel occlusion can be tolerated using superselective CPSS perfusion through an occluding endovascular catheter into the ischemic territory. This technique could possibly be applied in neurosurgery practice to the management of complex intracranial aneurysms.

Cerebral pressure autoregulation in traumatic brain injury.

An understanding of normal cerebral autoregulation and its response to pathological derangements is helpful in the diagnosis, monitoring, management, and prognosis of severe traumatic brain injury (TBI). Pressure autoregulation is the most common approach in testing the effects of mean arterial blood pressure on cerebral blood flow. A gold standard for measuring cerebral pressure autoregulation is not available, and the literature shows considerable disparity in methods. This fact is not surprising given that cerebral autoregulation is more a concept than a physically measurable entity. Alterations in cerebral autoregulation can vary from patient to patient and over time and are critical during the first 4-5 days after injury. An assessment of cerebral autoregulation as part of bedside neuromonitoring in the neurointensive care unit can allow the individualized treatment of secondary injury in a patient with severe TBI. The assessment of cerebral autoregulation is best achieved with dynamic autoregulation methods. Hyperventilation, hyperoxia, nitric oxide and its derivates, and erythropoietin are some of the therapies that can be helpful in managing cerebral autoregulation. In this review the authors summarize the most important points related to cerebral pressure autoregulation in TBI as applied in clinical practice, based on the literature as well as their own experience.

Intraventricular ganglioglioma.

Gangliogliomas are mixed tumors consisting of both glial elements and differentiated neurons. Although any part of the central nervous system can be affected, little is known about intraventricular gangliogliomas. A patient with a ganglioglioma is presented in the previously unreported location of the anterior third ventricle at the foramen of Monro, mimicking a colloid cyst. We review all other reported cases of intraventricular ganglioglioma (n=6) to characterize this entity. Intraventricular gangliogliomas typically affect younger patients with female predominance (male:female, 2:5; median age 25 years). Symptoms occur secondary to obstruction of physiological cerebrospinal fluid circulation. Complete surgical resection with re-establishment of cerebrospinal fluid drainage is the goal of treatment.

JNK1 regulates histone acetylation in trigeminal neurons following chemical stimulation.

Trigeminal nerve fibers in nasal and oral cavities are sensitive to various environmental hazardous stimuli, which trigger many neurotoxic problems such as chronic migraine headache and trigeminal irritated disorders. However, the role of JNK kinase cascade and its epigenetic modulation of histone remodeling in trigeminal ganglion (TG) neurons activated by environmental neurotoxins remains unknown. Here we investigated the role of JNK/c-Jun cascade in the regulation of acetylation of H3 histone in TG neurons following in vitro stimulation by a neuro-inflammatory agent, mustard oil (MO). We found that MO stimulation elicited JNK/c-Jun pathway significantly by enhancing phospho-JNK1, phospho-c-Jun expression, and c-Jun activity, which were correlated with an elevated acetylated H3 histone in TG neurons. However, increases in phospho-c-Jun and c-Jun activity were significantly blocked by a JNK inhibitor, SP600125. We also found that altered H3 histone remodeling, assessed by H3 acetylation in triggered TG neurons, was reduced by SP600125. The study suggests that the activated JNK signaling in regulation of histone remodeling may contribute to neuro-epigentic changes in peripheral sensory neurons following environmental neurotoxic exposure.

Cerebral phaeohyphomycosis mimics high-grade astrocytoma.

The incidence of cerebral phaeohyphomycosis, an infection caused by a dark-pigmented fungus, is increasing. The infection may mimic a high-grade glioma clinically and radiographically. Magnetic resonance spectroscopy may be helpful in differentiating the two. We report two cases to increase the awareness of cerebral phaeohyphomycosis in the clinical neurosciences. Early biopsy establishing the diagnosis, followed by aggressive combined surgical and medical management is necessary for a good outcome.

The role of c-AMP-dependent protein kinase in spinal cord and post synaptic dorsal column neurons in a rat model of visceral pain.

Visceral noxious stimulation induces central neuronal plasticity changes and suggests that the c-AMP-dependent protein kinase (PKA) signal transduction cascade contributes to long-term changes in nociceptive processing at the spinal cord level. Our previous studies reported the clinical neurosurgical interruption of post synaptic dorsal column neuron (PSDC) pathway by performing midline myelotomy effectively alleviating the intractable visceral pain in patients with severe pain. However, the intracellular cascade in PSDC neurons mediated by PKA nociceptive neurotransmission was not known. In this study, by using multiple experimental approaches, we investigated the role of PKA in nociceptive signaling in the spinal cord and PSDC neurons in a visceral pain model in rats with the intracolonic injection of mustard oil. We found that mustard oil injection elicited visceral pain that significantly changed exploratory behavior activity in rats in terms of decreased numbers of entries, traveled distance, active and rearing time, rearing activity and increased resting time when compared to that of rats receiving mineral oil injection. However, the intrathecal infusion of PKA inhibitor, H89 partially reversed the visceral pain-induced effects. Results from Western blot studies showed that mustard oil injection significantly induced the expression of PKA protein in the lumbosacral spinal cord. Immunofluorescent staining in pre-labeled PSDC neurons showed that mustard oil injection greatly induces the neuronal profile numbers. We also found that the intrathecal infusion of a PKA inhibitor, H89 significantly blocked the visceral pain-induced phosphorylation of c-AMP-responsive element binding (CREB) protein in spinal cord in rats. The results of our study suggest that the PKA signal transduction cascade may contribute to visceral nociceptive changes in spinal PSDC pathways.

Spontaneous spinal epidural arteriovenous fistulae in neurofibromatosis type-1.

BACKGROUND: NF-1 is one of the most common autosomal-dominantly inherited genetic disorders with an incidence of approximately 1:3500. We report a case and review the literature to characterize spontaneous spinal AVF that occur in neurofibromatosis (NF-1). CASE REPORT: A 51-year-old woman presented with NF-1 and progressive radiculomyelopathy. Angiography revealed an AVF terminating in a giant intraspinal epidural varix extending paraspinally through the C3/4 neural foramen. Trapping of the AVF attempted 18 years earlier prevented endovascular access for embolization, and vigorous bleeding made direct surgical resection impossible. Therefore, as palliation, arterial feeding collaterals were occluded, and surgically exposed tortuous veins were packed with coils. Laminectomies and partial resection of the epidural varix resulted in subtotal occlusion with clinical improvement. CONCLUSION: The spinal AVF associated with NF-1 appears to show dominant venous drainage to the intraspinal extradural and paraspinal venous plexus without evidence of intradural drainage. The vertebral artery is typically the origin of the fistula. A giant venous varix and numerous collateral feeders to the vertebral artery may give an AVM-like appearance. Clinically, the fistulae produce a syndromic triad including symptoms of NF-1, progressive radiculomyelopathy, and a bruit. Treatment is direct attack on the fistula by either surgery or embolization. If, however, a direct approach cannot be chosen, occlusion of feeding vessels combined with laminectomies can result in long-term symptomatic improvement.

Development and implementation of a problem-focused neurological assessment system.

A menu-driven, problem-focused neurological assessment system was constructed and implemented after concerns at a six-hospital teaching center about the quality of nursing assessments for patients with neurological diagnoses were validated. This system enables the physician to guide the nurse's assessment by ordering specific neurological tests for each patient. Extensive staff training took place to develop competence with this system. This new system has resulted in positive changes for this facility. Nurses acknowledge greater comfort with performing neurological assessment; documentation of assessment has improved; and the assessments are becoming more individualized for each patient. This system resulted in a higher quality of neurological care for patients.

Passive marker computer-aided sinonasal and cranial base surgery: observations from a learning curve.

To assess the feasibility of passive marker computer-aided surgery in a single institution, we performed 22 procedures in 21 patients with disorders including sinonasal tumors (n = 9), fungal sinusitis (n = 4), recurrent polyps (n = 3), chronic sinusitis (n = 3), and cerebrospinal fluid rhinorrhea (n = 2). Passive marker computer-aided surgery was successful in 19 of the 21 patients. The accuracy was on the order of 1.35 mm. Probe conversion, rotation, and cordlessness were helpful in all 19 cases. The system helped with landmarks (n = 14), margins (n = 7), skull base (n = 6), orbit (n = 5), and approach (n = 4). Computer-aided surgery accurately confirmed the location of an instrument and demonstrated tumor-normal tissue interfaces. It aided the surgeon in procedures on the sinonasal area and cranial base. The potential advantages of a passive marker system as compared with other available technologies center around the ability to convert and/or rotate virtually any instrument to a cordless imaging probe on demand during the operation.