Usefulness of minimum clinically important difference for assessing patients with subaxial degenerative cervical spine disease: statistical versus substantial clinical benefit.

BACKGROUND: The measurement of the therapeutic outcome of cervical spine surgeries commonly relies on four main patient reported outcomes (PROs): Neck Disability Index (NDI), Visual Analog Scale (VAS) for pain, and Short Form-36 (SF-36) Physical (PCS) and Mental (MCS) Component Summary. However, the clinical impact of such scores and how they could effectively measure therapeutic efficacy remains unclear. In this context, the concept of minimum clinically important difference (MCID) is developing into the standard by which to evaluate treatments, patient satisfaction and cost-effectiveness. METHODS: Eighty-eight consecutive patients undergoing surgery for subaxial degenerative cervical spine disease were selected from a prospective blinded database. PROs (NDI, PCS, MCS and VAS) were collected preoperatively, and together with blinded Surgeon Ratings (SR) at 3 months and 6 months post-surgery. Four anchor-based approaches were used to calculate different MCIDs. Three anchors (VAS, HTI (Health Transition Item of the SF-36) and SR) were used to evaluate surgery outcome. The best clinically and statistically relevant MCID was chosen. RESULTS: On average, all patients presented with a statistically significant improvement (p < 0.001) postoperatively for NDI (27.42 to 19.42), PCS (33.02 to 42.03), MCS (44 to 50.74) and VAS (2.85 to 1.93). The four MCID anchor-based approaches yielded a range of values for each PRO: 2.23-16.59 for PCS, 0.11-16.27 for MCS and 2.72-12.08 for NDI. When compared to the VAS and HTI anchors, the area under the ROC curve was greater for SR. This finding suggests that SR may be a more reliable anchor for MCID calculation. CONCLUSION: The MDC (minimum detectable change) approach together with the SR anchor appears to be the most appropriate MCID method. It offers the greatest area under the ROC curve (threshold above the 95 % CI), and the choice of the anchor did not significantly affect this result. MCID values for this dataset were 5.6 for PCS, 5.12 for MCS and 2.41 for NDI.

Comparison between patient and surgeon perception of degenerative spine disease outcomes--a prospective blinded database study.

BACKGROUND: Few have studied the correlation between patients' and spine surgeons' perception on outcomes, or compared these with patient-reported outcome scores. Outcomes studies are increasingly important in evaluating costs and benefits to patients and surgeons, and in developing metrics for payer evaluation and health care policy-making. OBJECTIVE: To compare patients' and surgeons' assessment of spine treatment outcome in a prospective blinded patient-driven spine surgery outcomes registry, and to correlate perceived outcomes ratings to validated outcomes scores. METHODS: Patients filled out surveys at baseline, 3 months and 6 months postoperatively, including Visual Analog Scale (VAS), and Neck Disability Index (NDI) or Oswestry Disability Index (ODI). Outcome was rated independently by patients and surgeons on a 7-point Likert-type scale. RESULTS: Two-hundred and sixty-five consecutive adult patients were surgical candidates. Of these, 154 (58.1 %) opted for surgery, with 69 (44.8 %) cervical and 85 (55.2 %) lumbar patients. One hundred and thirty-five (87.7 %) had both patient and surgeon postoperative ratings. Surgeons' and patients' ratings correlated strongly (Spearman rho = 0.53, p < 0.0001, 45.9 % identical, 88.2 % +/- 1 grade). The surgeon rated outcomes were better than patients in 29.8 % and worse in 21.15 %. Patient rating correlated better with the most recent NDI/ODI and pain scores than with incremental change from baseline. In multivariate analysis, age, location (cervical vs lumbar), pain ratings, and functional scores (NDI, ODI) did not have significant impact on the discrepancy between patient and surgeon ratings. CONCLUSIONS: Patients' and surgeons' global outcome ratings for spinal disease correlate highly. Patients' ratings correlate better with most recent functional scores, rather than incremental change from baseline.

Endocrine assessment, chemotherapy, nonsurgical treatment, and rehabilitation for osteoporotic spine fractures: WFNS spine committee recommendations.

INTRODUCTION: We reviewed the endocrine assessment, chemotherapy, and rehabilitation of the osteoporotic vertebral fractures (OVF) to create recommendations for the disease. EVIDENCE ACQUISITION: A PubMed and Medline search between 2011 and 2021 was conducted using key words. Case reports, experimental studies, papers other than the English language, and unrelated studies were excluded. Up-to-date information on endocrine assessment, medical and nonsurgical treatment, and rehabilitation for osteoporotic spine fractures were reviewed, and statements were produced to reach a consensus in two separate virtual consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee. The statements were voted and achieved a positive or negative consensus using Delphi method. EVIDENCE SYNTHESIS: Endocrine assessment of osteoporosis is necessary if it is diagnosed in premenopausal women or men less than 50 years of age. Dual X-Ray absorptiometry (DXA) alone may not be predictive of fracture. Endocrine causes of osteoporosis must also be evaluated if the Z-score ≤-2.0. In case of a vertebral fracture in postmenopausal women and men aged 50 years and above, pharmacologic treatment for osteoporosis must be started. Strengthening exercise, balance and gait training, and assistive devices are recommended to prevent and reduce falls in the elderly. In addition, rehabilitation must be a part of the overall treatment to help patients return to function. CONCLUSIONS: Nonsurgical management helps treat OVF. Although there is weak evidence on the type of medical treatment and usage of braces, bed rest, and other measures, current literature supports endocrinological management, medical treatment, and rehabilitation after osteoporotic vertebral fractures.

A review of lumbar spinal instrumentation: evidence and controversy.

Disability secondary to disorders of the spine is a significant problem worldwide. In the USA, there has been a recent surge in the costs associated with caring for spinal pathology; from 1997 to 2005, there was a growth of 65% in healthcare expenditures on spinal disease, totalling $86 billion in 2005. Increasingly, there has been media and public scrutiny over the rapid rise in the volume of procedures with spinal instrumentation; some have suggested that this rise has been fuelled by non-medical drivers such as the financial incentives involved with the use of instrumentation; others suggest that innovation in spine technology and devices has led to improved options for the treatment of spine pathology.In this context, we conducted a review of the literature to assess the use of instrumentation in lumbar procedures and its relationship to successful fusion and patient outcome. Our review suggests that there is data supporting the thesis that lumbar instrumentation improves rates of fusion. However, there is no consistent correlation between increased rates of fusion and improved patient outcomes.

Mobility-Preserving Surgery for Lumbar Spinal Stenosis: WFNS Spine Committee Recommendations.

BACKGROUND: Although decompression is the basis of surgical treatment for lumbar spinal stenosis (LSS), under various circumstances instrumented fusion is performed as well. The rationale for mobility-preserving operations for LSS is preventing adjacent segment disease (ASD). We review the rationale for mobility preservation in ASD and discuss related topics such as indications for fusion and the evolving role of minimally invasive approaches to lumbar spine decompression. Our focus is on systematic review and consensus discussion of mobility-preserving surgical methods as related to surgery for LSS. METHODS: Groups of spinal surgeons (members of the World Federation of Neurosurgical Societies Spine Committee) performed systematic reviews of dynamic fixation systems, including hybrid constructs, and of interspinous process devices; consensus statements were generated based on the reviews at 2 voting sessions by the committee several months apart. Additional review of background data was performed, and the results summarized in this review. RESULTS: Decompression is the basis of surgical treatment of LSS. Fusion is an option, especially when spondylolisthesis or instability are present, but indications remain controversial. ASD incidence reports show high variability. ASD may represent the natural progression of degenerative disease in many cases. Older age, poor sagittal balance, and multilevel fusion may be associated with more ASD. Dynamic fixation constructs are treatment options that may help prevent ASD.

Prediction of ventriculoperitoneal shunt dependency in patients with aneurysmal subarachnoid hemorrhage.

OBJECT: Patients with subarachnoid hemorrhage treated using external ventricular drainage due to obstructive hydrocephalus commonly remain shunt-dependent. Based on identified risk factors for external ventricular drain (EVD) challenge failure, the authors sought to determine the likelihood that a patient will require a permanent shunt. METHODS: The authors reviewed 89 consecutive cases of aneurysmal subarachnoid hemorrhage with obstructive hydrocephalus for parameters associated with EVD challenge failure and permanent shunt requirement. Significant parameters were combined in a discriminant function analysis to create a failure risk index (FRI). Linear regression analysis was performed correlating the FRI with the actual rate of shunt dependency. RESULTS: Patients requiring a permanent shunt had: a larger third ventricular diameter (7.0 vs 5.4 mm; p = 0.02) and a higher Hunt and Hess grade (3 vs 2; p = 0.02) at the time of admission; and a larger third ventricular diameter (6.6 vs 5.2 mm; p = 0.04), a larger bicaudate diameter (31.9 vs 30.2 mm; p = 0.03), and higher CSF protein levels (76.5 vs 40.3 mg/dl; p < 0.0001) at the onset of EVD challenge. These patients were also more likely to be female (p = 0.01) and have a posterior circulation location of their aneurysm (p = 0.01). The FRI score was calculated based on a weighted combination of the above parameters. Linear regression analysis between FRI values and the percentage of patients who required a permanent shunt had a correlation coefficient of 91%; the risk of a permanent shunt requirement increased linearly with a rising FRI score. CONCLUSIONS: An FRI score created by discriminant function analysis can predict whether or not a permanent shunt is required, even if separate factors are not in agreement with each other or show a weak correlation when considered separately. An increased FRI score was strongly and linearly correlated with the risk of EVD challenge failure. A prospective study is necessary to validate the FRI.

Hydrocephalus in posterior fossa lesions: ventriculostomy and permanent shunt rates by diagnosis.

OBJECTIVES: The rate of ventriculostomy for acute hydrocephalus and progression to shunt-dependent chronic hydrocephalus in patients with posterior fossa lesions are not well known. METHODS: We retrospectively reviewed 104 consecutive cases with posterior fossa lesions on admission to the University of Illinois Hospital from June 2002 to December 2005. We recorded the rate of ventriculostomy and permanent ventricular shunting, which were compared among etiologic groups, using chi-squared and Fisher's exact tests. RESULTS: Overall, 35 patients had ventriculostomy for acute hydrocephalus and 16 had permanent shunting for shunt-dependent chronic hydrocephalus. Of those with primary posterior fossa intracranial hemorrhage (ICH) (42 cases), 19 (45%) required ventriculostomy, with five (26%) requiring subsequent permanent shunting; 13 patients had hematoma evacuation, with two having permanent shunting. Of those with cerebellar infarction (14 cases), four (29%) required ventriculostomy and one (25%) had a permanent shunt; two had a decompressive craniectomy. Of those with neoplasms (43 cases, 33 surgically resected), ten (23%) required ventriculostomy and nine (21%) required permanent shunting. In addition, two of the three cases with infectious processes required ventriculostomy and one required a permanent shunt. In-hospital mortality was 21% (9/42 cases) for patients with ICH, 14% (2/14 cases) for patients with infarction and 0% for all others. DISCUSSION: Acute primary posterior fossa hemorrhage has the highest rate of ventriculostomy for acute hydrocephalus and highest inpatient mortality but a surprisingly low rate of permanent shunt-dependency. When hydrocephalus was caused by a neoplasm, there was a higher rate of permanent shunt placement.

Posterior Surgical Techniques for Cervical Spondylotic Myelopathy: WFNS Spine Committee Recommendations.

OBJECTIVE: This study was conducted to determine and recommend the most up-to-date information on the indications, complications, and outcomes of posterior surgical treatments for cervical spondylotic myelopathy (CSM) on the basis of a literature review. METHODS: A comprehensive literature search was performed, using the MEDLINE (PubMed), the Cochrane Register of Controlled Trials, and Web of Science databases, for peer-reviewed articles published in English during the last 10 years. RESULTS: Posterior techniques, which include laminectomy alone, laminectomy with fusion, and laminoplasty, are often used in patients with involvement of 3 or more levels. Posterior decompression for CSM is effective for improving patients' neurological function. Complications resulting from posterior cervical spine surgery include injury to the spinal cord and nerve roots, complications related to posterior screw fixation or instrumentation, C5 palsy, spring-back closure of lamina, and postlaminectomy kyphosis. CONCLUSION: It is necessary to consider multiple factors when deciding on the appropriate operation for a particular patient. Surgeons need to tailor preoperative discussions to ensure that patients are aware of these facts. Further research is needed on the cost-to-benefit analysis of various surgical approaches, the comparative efficacy of surgical approaches using various techniques, and long-term outcomes, as current knowledge is deficient in this regard.

GDNF-secreting human neural progenitor cells increase tyrosine hydroxylase and VMAT2 expression in MPTP-treated cynomolgus monkeys.

Human neural progenitor cells (hNPCs) have been proposed as a potential source of cells for ex vivo gene therapy. In this pilot study, three 5-year-old female cynomolgus monkeys received a single intracarotid infusion of MPTP, followed 1 week later by MRI-guided stereotaxic intrastriatal and intranigral injections of male hNPCs transgenic for GDNF. Immunosupression with oral cyclosporine (30-40 mg/kg) began 48 h before hNPC transplants and continued throughout the study. We monitored the animals using a clinical rating scale (CRS). Three months postsurgery, we euthanized the animals by transcardiac perfusion, then retrieved and processed their brains for morphological analysis. Our findings include the following. 1) hNPCs survived and produced GDNF in all animals 3 months postsurgery. 2) hNPCs remained in the areas of injection as observed by GDNF immunostaining and in situ hybridization for the human Y chromosome. 3) A "halo" of GDNF expression was observed diffusing from the center of the graft out into the surrounding area. 4) We observed increased TH- and VMAT2-positive fibers in areas of GDNF delivery in two of the three animals. The two animals with TH- and VMAT2-positive fibers also showed reductions in their CRS scores. 5) Some GFAP-positive perivascular cuffing was found in transplanted areas. 6) General blood chemistry and necropsies did not reveal any abnormalities. Therefore, we conclude that hNPCs releasing GDNF may be a possible alternative for intracerebral trophic factor delivery in Parkinson's disease.

Subthalamic glutamic acid decarboxylase gene therapy: changes in motor function and cortical metabolism.

Parkinson's disease (PD) is associated with increased excitatory activity within the subthalamic nucleus (STN). We sought to inhibit STN output in hemiparkinsonian macaques by transfection with adeno-associated virus (AAV) containing the gene for glutamic acid decarboxylase (GAD). In total, 13 macaques were rendered hemiparkinsonian by right intracarotid 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injection. Seven animals were injected with AAV-GAD into the right STN, and six received an AAV gene for green fluorescent protein (GFP). Videotaped motor ratings were performed in a masked fashion on a weekly basis over a 55-week period. At 56 weeks, the animals were scanned with (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Histological examination was performed at the end of the study. No adverse events were observed after STN gene therapy. We found that the clinical rating scores for the two treatment groups had different patterns of change over time (group x time interaction, P<0.001). On FDG PET, the GAD animals exhibited an increase in glucose utilization in the right motor cortex relative to GFP controls (P<0.001). Metabolism in this region correlated with clinical ratings at end point (P<0.01). Histology confirmed GAD expression in treated animals. These findings suggest that STN AAV-GAD is well tolerated and potentially effective in a primate model of PD. The changes in motor cortical glucose utilization observed after gene therapy are consistent with the modulation of metabolic brain networks associated with this disorder.

Cardiac complications after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Cardiac complications are frequently encountered by neurointensivists caring for patients with SAH. Our aim was to better characterize the natural history of various cardiac abnormalities in this population. We sought to determine the risk factors for cardiac abnormalities, patient outcome, and impact of treatment type on cardiac abnormalities. METHODS: We performed a single center retrospective review of admissions of patients with aneurysmal SAH to the neurosurgical ICU in a large university hospital. Patient demographics, pertinent history, cardiac tests, hospital LOS, intervention type, and discharge outcome were collected. RESULTS: Data from 266 patients were available for analysis. Of these patients, 50% (n = 133) demonstrated cardiac abnormalities as indicated by abnormal EKG, ECHO, or troponin I. Only age was determined to be an independent statistically significant predictor of cardiac abnormality (P = .01). There was no difference in mortality between the cardiac abnormality and control groups (P = .33). However, there was increased morbidity in the cardiac abnormality group as demonstrated by worse discharge disposition, in addition to increased length of hospital stay (22.6 vs 17.1 days, P < .01). The incidence of cardiac abnormalities was the same among surgical and endovascular treatment groups. CONCLUSIONS: Cardiac abnormalities, including those that meet ACC criteria for MI, are common among patients with SAH. However, in contrast to cardiac events outside the context of SAH, these abnormalities do not increase mortality. They do, however, adversely affect discharge disposition and prolong hospital LOS. The type of aneurysm treatment does not affect the incidence or outcome of cardiac abnormalities.

Clinical Outcomes of Cervical Laminoplasty: Results at Two Years.

BACKGROUND: Laminoplasty is an established treatment for cervical myelopathy. Multiple variations have emerged, many advocating the use of allograft, but controversy persists. OBJECTIVE: To assess medium-term clinical outcomes in patients who underwent laminoplasty with autograft at our institution. METHODS: Thirty-two consecutive patients (19 male, 13 female, average age 66 yr) from our prospective outcome registry that underwent cervical laminoplasty between 2009 and 2013 were reviewed. Computed tomography (CT) scan was performed immediately postoperatively and at 6-mo follow-up. Parameters included patient perception of outcome, Nurick score, Neck Disability Index (NDI), visual analog scale for neck pain, and SF-36. RESULTS: On retrospective analysis, all patients felt improved at 3 mo postoperatively; at 2 yr, this rate was 91%. Improvements were seen in Nurick scores, from 3.16 ± 0.9 preoperatively to 1.94 ± 0.8 at 2 yr; NDI score from 28.7% ± 9% preoperatively to 20.8% ± 9.6% at 2 yr; visual analog scale from 2.8 ± 1.2 preoperatively to 1.7 ± 0.9 at 2 yr; and SF-36 physical component summary from 27.9 ± 10 preoperatively to 37.8 ± 11.9 at 2 yr. All values reached significance at all follow-up points ( P < .05) with the exception of 6-mo NDI values ( P = .062). No C5 palsy, graft complications, or reclosure was observed in any patient during the follow-up period. CONCLUSION: Laminoplasty with autograft is a safe and effective method to treat cervical myelopathy, with good medium-term clinical outcome. No reclosures were observed. Bony fusion was seen in all cases on CT scan. Our study found good outcomes in the performance of open-door laminoplasty without hardware, in the treatment of cervical stenosis.

Survival and early differentiation of human neural stem cells transplanted in a nonhuman primate model of stroke.

OBJECT: Neural cell transplantation has been proposed as a treatment after stroke. The purpose of this study was to establish if human neural stem cells (HNSCs) could survive in the nonhuman primate brain after an ischemic event. METHODS: Three adult cynomolgus monkeys received a unilateral occlusion of the M, segment of the right middle cerebral artery (MCA). One week later each animal received five magnetic resonance (MR) image-guided stereotactic intracerebral injections of HNSC neurospheres labeled with bromodeoxyuridine (BrdU) in the areas surrounding the ischemic lesion as defined in T1- and T2-weighted images. On the day of transplantation and throughout the study the monkeys received oral cyclosporine (10 mg/kg twice a day), and plasma levels were monitored routinely. The animals were killed at 45, 75, or 105 days after transplantation. Magnetic resonance images revealed a cortical and subcortical infarction in the MCA distribution area. Postmortem morphological brain analyses confirmed the distribution of the infarcted area seen in the MR images, with loss of tissue and necrosis in the ischemic region. Cells that were positive for BrdU were present in the three experimental monkeys, mainly along injection tracks. Double-label immunofluorescence for BrdU and betaIII-tubulin (a marker of young neurons) revealed colocalization of few HNSCs, most of which were observed outside the immediate injection site. Colocalization with nestin was also observed, indicating an early neural/glial fate. CONCLUSIONS: In a model of stroke in nonhuman primates, HNSCs can survive up to 105 days when transplanted 1 week after an ischemic event and can partly undergo neuronal differentiation.

Implantation and testing of WFMA stimulators in macaque.

Our on-going work to develop an intracortical visual prosthesis has motivated the design, fabrication, and testing of a Wireless Floating Microelectrode Array (WFMA) stimulator. This implantable device can be used for an electrical stimulation interface in the peripheral and the central nervous system. Previously, its use in a sciatic nerve rodent model was described. Here implantation of two WFMAs in motor cortex of two NHP (macaque - two devices/animal) is presented. Preliminary functional tests show the implanted devices to be fully functional with stimulation-induced motor movements obtained. Functional testing is on-going.

Evaluation of Sensory and Motor Skills in Neurosurgery Applicants Using a Virtual Reality Neurosurgical Simulator: The Sensory-Motor Quotient.

OBJECTIVE: Manual skill is an important attribute for any surgeon. Current methods to evaluate sensory-motor skills in neurosurgical residency applicants are limited. We aim to develop an objective multifaceted measure of sensory-motor skills using a virtual reality surgical simulator. DESIGN: A set of 3 tests of sensory-motor function was performed using a 3-dimensional surgical simulator with head and arm tracking, collocalization, and haptic feedback. (1) Trajectory planning: virtual reality drilling of a pedicle. Entry point, target point, and trajectory were scored-evaluating spatial memory and orientation. (2) Motor planning: sequence, timing, and precision: hemostasis in a postresection cavity in the brain. (3) Haptic perception: touching virtual spheres to determine which is softest of the group, with progressive difficulty. Results were analyzed individually and for a combined score of all the tasks. SETTING: The University of Chicago Hospital's tertiary care academic center. PARTICIPANTS: A total of 95 consecutive applicants interviewed at a neurosurgery residency program over 2 years were offered anonymous participation in the study; in 2 cohorts, 36 participants in year 1 and 27 participants in year 2 (validation cohort) agreed and completed all the tasks. We also tested 10 first-year medical students and 4 first- and second-year neurosurgery residents. RESULTS: A cumulative score was generated from the 3 tests. The mean score was 14.47 (standard deviation = 4.37), median score was 13.42, best score was 8.41, and worst score was 30.26. Separate analysis of applicants from each of 2 years yielded nearly identical results. Residents tended to cluster on the better performance side, and first-year students were not different from applicants. CONCLUSIONS: (1) Our cumulative score measures sensory-motor skills in an objective and reproducible way. (2) Better performance by residents hints at validity for neurosurgery. (3) We were able to demonstrate good psychometric qualities and generate a proposed sensory-motor quotient distribution in our tested population.

Usefulness of a Virtual Reality Percutaneous Trigeminal Rhizotomy Simulator in Neurosurgical Training.

BACKGROUND: Simulation-based training may be incorporated into neurosurgery in the future. OBJECTIVE: To assess the usefulness of a novel haptics-based virtual reality percutaneous trigeminal rhizotomy simulator. METHODS: A real-time augmented reality simulator for percutaneous trigeminal rhizotomy was developed using the ImmersiveTouch platform. Ninety-two neurosurgery residents tested the simulator at American Association of Neurological Surgeons Top Gun 2014. Postgraduate year (PGY), number of fluoroscopy shots, the distance from the ideal entry point, and the distance from the ideal target were recorded by the system during each simulation session. Final performance score was calculated considering the number of fluoroscopy shots and distances from entry and target points (a lower score is better). The impact of PGY level on residents' performance was analyzed. RESULTS: Seventy-one residents provided their PGY-level and simulator performance data; 38% were senior residents and 62% were junior residents. The mean distance from the entry point (9.4 mm vs 12.6 mm, P = .01), the distance from the target (12.0 mm vs 15.2 mm, P = .16), and final score (31.1 vs 37.7, P = .02) were lower in senior than in junior residents. The mean number of fluoroscopy shots (9.8 vs 10.0, P = .88) was similar in these 2 groups. Linear regression analysis showed that increasing PGY level is significantly associated with a decreased distance from the ideal entry point (P = .001), a shorter distance from target (P = .05), a better final score (P = .007), but not number of fluoroscopy shots (P = .52). CONCLUSION: Because technical performance of percutaneous rhizotomy increases with training, we proposed that the skills in performing the procedure in our virtual reality model would also increase with PGY level, if our simulator models the actual procedure. Our results confirm this hypothesis and demonstrate construct validity.

Virtual reality cerebral aneurysm clipping simulation with real-time haptic feedback.

BACKGROUND: With the decrease in the number of cerebral aneurysms treated surgically and the increase of complexity of those treated surgically, there is a need for simulation-based tools to teach future neurosurgeons the operative techniques of aneurysm clipping. OBJECTIVE: To develop and evaluate the usefulness of a new haptic-based virtual reality simulator in the training of neurosurgical residents. METHODS: A real-time sensory haptic feedback virtual reality aneurysm clipping simulator was developed using the ImmersiveTouch platform. A prototype middle cerebral artery aneurysm simulation was created from a computed tomographic angiogram. Aneurysm and vessel volume deformation and haptic feedback are provided in a 3-dimensional immersive virtual reality environment. Intraoperative aneurysm rupture was also simulated. Seventeen neurosurgery residents from 3 residency programs tested the simulator and provided feedback on its usefulness and resemblance to real aneurysm clipping surgery. RESULTS: Residents thought that the simulation would be useful in preparing for real-life surgery. About two-thirds of the residents thought that the 3-dimensional immersive anatomic details provided a close resemblance to real operative anatomy and accurate guidance for deciding surgical approaches. They thought the simulation was useful for preoperative surgical rehearsal and neurosurgical training. A third of the residents thought that the technology in its current form provided realistic haptic feedback for aneurysm surgery. CONCLUSION: Neurosurgical residents thought that the novel immersive VR simulator is helpful in their training, especially because they do not get a chance to perform aneurysm clippings until late in their residency programs.

Delayed onset of progressive dystonia following subacute 3-nitropropionic acid treatment in Cebus apella monkeys.

Delayed abnormal movements can be observed in patients with acute neurologic insult after a prolonged period of apparent neurologic stability. To reproduce such a secondary neurologic manifestation in primates, the present experiment investigated whether systemic administration of subacute 3-nitropropionic acid (3NP), a mitochondrial toxin, could induce abnormal movements that were delayed and progressive over time. Four Cebus apella monkeys received systemic 3NP injections until acute neurologic signs manifested. The monkeys were regularly video-recorded and rated for abnormal movements for up to 15 weeks after the cessation of 3NP treatment. Five to 6 weeks after the 3NP treatment, monkeys displayed a significant increase in dyskinesias compared with pretreatment conditions. Over time the chorea attenuated, whereas the dystonic movements increased in intensity and severity which was characterized by a delayed decrease of peak tangential velocity. The intensity of abnormal movements and extent of affected body regions observed in each monkey were consistent with the size of basal ganglia hypersignal as documented by T2 sequence on magnetic resonance imaging. Thus, more severe motor impairments were associated with large magnetic resonance image abnormalities. This novel primate model may be particularly useful for studying the structural changes underlying delayed and progressive manifestations of abnormal movements with the ultimate goal of facilitating the evaluation of novel therapeutic strategies.

Prevention of pulmonary embolism by combined modalities of thromboprophylaxis and intensive surveillance protocol.

OBJECTIVE: Deep vein thrombosis (DVT) is a known complication in neurosurgical patients. The protocols for the prevention of DVT and pulmonary embolism (PE) are not applied universally. Our goal was to review the incidence of DVT and PE in neurosurgical intensive care units (NSICUs) and to compare it with the incidence of DVT and PE in other intensive care units (ICUs) in the same hospital. METHODS: We retrospectively reviewed 5327 consecutive admissions in all intensive care units at the University of Illinois Hospital between July 2001 and June 2002. The NSICU had 1094 admissions, and all other ICUs combined had 4233 admissions. In our NSICU, every patient was administered DVT prophylaxis in the form of subcutaneous heparin and a sequential compression device if these treatments were not contraindicated. Lower-extremity venous Doppler ultrasonography was performed twice weekly in all NSICU patients. There was no routine use of DVT prophylaxis in the other ICUs, and no other ICUs performed routine lower-extremity venous Doppler ultrasonography. We compared the incidence of DVT and PE in the NSICU and the combined population of other adult ICUs. RESULTS: PE was diagnosed in 1 (0.09%) of 1094 patients in the NSICU and in 45 (1.06%) of 4233 patients in all other ICUs (P < 0.0001, Z = 5.34). DVT was diagnosed in 28 patients (2.55%) in the NSICU and in 238 patients (5.62%) in all other ICUs (P < 0.001, Z = 4.32). These values suggest a statistically significant difference in the incidence of DVT and PE in the NSICU compared with all other ICUs. CONCLUSION: We conclude that there was a significantly lower incidence of DVT and PE in the NSICU than in all other ICUs at our institution. DVT prophylaxis and twice-weekly lower-extremity venous Doppler screening in the NSICU have been found to be beneficial in decreasing the incidence of DVT and particularly effective in preventing PE.