The Role of Additional Spine Surgery in the Management of Failed Back Surgery Syndrome, Complex Regional Pain Syndrome, and Intractable Pain in the Setting of Previous or Concurrent Spinal Cord Stimulation: Indications and Outcomes.

OBJECTIVE: Spinal cord stimulation (SCS) is both relatively safe and reversible. Although SCS is generally regarded as a last resort, some of these patients will undergo additional spinal surgery after the device has been implanted or after its removal. We present a descriptive study of subsequent spinal surgery after SCS implantation. METHODS: A retrospective review of patients who had undergone percutaneous or paddle SCS lead placement at our institution from 2009 to 2016 was performed. Patients who had only undergone trials or who had not undergone spine surgery after SCS implantation were excluded. RESULTS: We identified 22 patients (5.7%) who had undergone spine surgery during the course of SCS treatment or after SCS removal, or both, of a total 383 patients who had undergone paddle and/or percutaneous SCS implantation. The most common additional spine interventions included lumbosacral decompression and fusion (n = 15; 42%). Of 36 surgeries, the most frequent indications for subsequent intervention were stenosis or restenosis (n = 16; 73%) and spine deformity (n = 6; 27%). The median EuroQol-5D index was 0.397 preoperatively and 0.678 postoperatively. CONCLUSIONS: To the best of our knowledge, the present study is the first to describe spine surgery in the setting of SCS implantation. Our results have indicated that spine surgery subsequent to, or concurrent with, SCS implantation appears to occur in few patients. Our study results suggest a modest improvement in quality of life outcomes. Therefore, clinicians should remember that patients might require further spine surgery despite the use of SCS implantation and, thus, might require reevaluation by the spine team.

Quality of Life Improvement Following Deep Brain Stimulation for Parkinson Disease: Development of a Prognostic Model.

BACKGROUND: There is a growing attention to determine the factors that predict quality of life (QoL) improvement after deep brain stimulation (DBS) for Parkinson's disease. Prior literature has largely focused on examining predictors one at a time, sometimes controlling for covariates. OBJECTIVE: To develop a model that could be used as a nomogram to predict improvement in QoL following DBS surgery in patients with Parkinson's disease. METHODS: All patients with complete pre- and postoperative movement disorder and neuropsychological testing who underwent DBS at a single institution between 2007-2012 were analyzed. The Parkinson's Disease Questionnaire-39 (PDQ-39) was used to measure QoL. Potential predictive factors, including patient demographics, clinical presentation characteristics, radiographic imaging, and motor and psychological testing were analyzed for impact on QoL. RESULTS: Sixty-seven patients were identified, 36 (53.73%) of whom had meaningfully improved QoL following surgery. Five baseline variables showed significant relationships with the outcome: years since symptom onset, percent change in on/off motor evaluation, levodopa equivalent daily dose, bilateral vs unilateral DBS implantation, and PDQ-39 score. The final model includes PDQ-39, percent change in UPRS-III, and years since symptom onset and is able to predict improvement in QoL with 81% accuracy. CONCLUSION: Our model accurately predicted whether QoL would improve in patients undergoing subthalamic nucleus DBS 81% of the time. Our data may serve as the foundation to further refine a clinically relevant prognostic tool that would assist the decision-making process for clinicians and DBS multidisciplinary teams assessing patient candidacy for surgery.

Prediction of depression and anxiety via patient-assessed tremor severity, not physician-reported motor symptom severity, in patients with Parkinson's disease or essential tremor who have undergone deep brain stimulation.

OBJECTIVEDeep brain stimulation (DBS) is an effective therapy for movement disorders such as idiopathic Parkinson's disease (PD) and essential tremor (ET). However, some patients who demonstrate benefit on objective motor function tests do not experience postoperative improvement in depression or anxiety, 2 important components of quality of life (QOL). Thus, to examine other possible explanations for the lack of a post-DBS correlation between improved objective motor function and decreased depression or anxiety, the authors investigated whether patient perceptions of motor symptom severity might contribute to disease-associated depression and anxiety.METHODSThe authors performed a retrospective chart review of PD and ET patients who had undergone DBS at the Cleveland Clinic in the period from 2009 to 2013. Patient demographics, diagnosis (PD, ET), motor symptom severity, and QOL measures (Primary Care Evaluation of Mental Disorders 9-item Patient Health Questionnaire [PHQ-9] for depression, Generalized Anxiety Disorder 7-item Scale [GAD-7], and patient-assessed tremor scores) were collected at 4 time points: preoperatively, postoperatively, 1-year follow-up, and 2-year follow-up. Multivariable prediction models with solutions for fixed effects were constructed to assess the correlation of predictor variables with PHQ-9 and GAD-7 scores. Predictor variables included age, sex, visit time, diagnosis (PD vs ET), patient-assessed tremor, physician-reported tremor, Unified Parkinson's Disease Rating Scale part III (UPDRS-III) score, and patient-assessed tremor over time.RESULTSSeventy PD patients and 17 ET patients were included in this analysis. Mean postoperative and 1-year follow-up UPDRS-III and physician-reported tremor scores were significantly decreased compared with preoperative scores (p < 0.0001). Two-year follow-up physician-reported tremor was also significantly decreased from preoperative scores (p < 0.0001). Only a diagnosis of PD (p = 0.0047) and the patient-assessed tremor rating (p < 0.0001) were significantly predictive of depression. A greater time since surgery, in general, significantly decreased anxiety scores (p < 0.0001) except when a worsening of patient-assessed tremor was reported over the same time period (p < 0.0013).CONCLUSIONSPatient-assessed tremor severity alone was predictive of depression in PD and ET following DBS. This finding suggests that a patient's perception of illness plays a greater role in depression than objective physical disability regardless of the time since surgical intervention. In addition, while anxiety may be attenuated by DBS, patient-assessed return of tremor over time can increase anxiety, highlighting the importance of long-term follow-up for behavioral health features in chronic neurological disorders. Together, these data suggest that the patient experience of motor symptoms plays a role in depression and anxiety-a finding that warrants consideration when evaluating, treating, and following movement disorder patients who are candidates for DBS.

Deep brain stimulation outcomes in patients implanted under general anesthesia with frame-based stereotaxy and intraoperative MRI.

OBJECTIVEThe authors' aim in this study was to evaluate placement accuracy and clinical outcomes in patients who underwent implantation of deep brain stimulation devices with the aid of frame-based stereotaxy and intraoperative MRI after induction of general anesthesia.METHODSThirty-three patients with movement disorders (27 with Parkinson's disease) underwent implantation of unilateral or bilateral deep brain stimulation systems (64 leads total). All patients underwent the implantation procedure with standard frame-based techniques under general anesthesia and without microelectrode recording. MR images were acquired immediately after the procedure and fused to the preoperative plan to verify accuracy. To evaluate clinical outcome, different scales were used to assess quality of life (EQ-5D), activities of daily living (Unified Parkinson's Disease Rating Scale [UPDRS] part II), and motor function (UPDRS part III during off- and on-medication and off- and on-stimulation states). Accuracy was assessed by comparing the coordinates (x, y, and z) from the preoperative plan and coordinates from the tip of the lead on intraoperative MRI and postoperative CT scans.RESULTSThe EQ-5D score improved or remained stable in 71% of the patients. When in the off-medication/on-stimulation state, all patients reported significant improvement in UPDRS III score at the last follow-up (p < 0.001), with a reduction of 25.2 points (46.3%) (SD 14.7 points and 23.5%, respectively). There was improvement or stability in the UPDRS II scores for 68% of the Parkinson's patients. For 2 patients, the stereotactic error was deemed significant based on intraoperative MRI findings. In these patients, the lead was removed and replaced after correcting for the error during the same procedure. Postoperative lead revision was not necessary in any of the patients. Based on findings from the last intraoperative MRI study, the mean difference between the tip of the electrode and the planned target was 0.82 mm (SD 0.5 mm, p = 0.006) for the x-axis, 0.67 mm (SD 0.5 mm, p < 0.001) for the y-axis, and 0.78 mm (SD 0.7 mm, p = 0.008) for the z-axis. On average, the euclidian distance was 1.52 mm (SD 0.6 mm). In patients who underwent bilateral implantation, accuracy was further evaluated comparing the first implanted side and the second implanted side. There was a significant mediolateral (x-axis) difference (p = 0.02) in lead accuracy between the first (mean 1.02 mm, SD 0.57 mm) and the second (mean 0.66 mm, SD 0.50 mm) sides. However, no significant difference was found for the y- and z-axes (p = 0.10 and p = 0.89, respectively).CONCLUSIONSFrame-based DBS implantation under general anesthesia with intraoperative MRI verification of lead location is safe, accurate, precise, and effective compared with standard implantation performed using awake intraoperative physiology. More clinical trials are necessary to directly compare outcomes of each technique.

Rate of Complications Following Spinal Cord Stimulation Paddle Electrode Removal.

OBJECTIVE: Spinal cord stimulation (SCS) is a safe, reversible surgical treatment for complex regional pain syndrome and failed back surgery syndrome refractory to conventional medical management. Paddle electrodes are routinely used for the permanent implant because of the reduced risk of migration, lower energy requirements, and expanded coverage options. The risks associated with paddle lead removal are not well defined in the literature. METHODS: We retrospectively reviewed the outcomes of all patients at the Cleveland Clinic who underwent removal of SCS paddle electrodes between 2009 and 2016. RESULTS: We identified 68 patients during this interval who had a paddle electrode removed. The most common reason for removal was loss of coverage or effect (75%), followed by infection (13.24%), and the need for magnetic resonance imaging for diagnostic purposes (8.82%). Postoperative complications occurred in eight patients (11.75%), two of which were classified as major (2.94%). One of these patients developed a postoperative cerebrospinal fluid leak, and another suffered a large suprafascial hematoma. Both patients underwent reoperation. Minor complications were reported in six patients (8.82%) and included wound dehiscence, infection, and prolonged ileus in one case. On average, patients who developed complications lost 20 mL more blood during surgery than those who did not develop complications (p = 0.006). CONCLUSION: One of the benefits of SCS therapy is the reversibility of the procedure. However, removal is not without some risk though the overall risk of minor or major complication is low. Patients who are considering removal should be counseled appropriately. Prophylactic removal is not recommended. However, when removal is needed, surgeons and pain specialists must be familiar with these complications and their management.

The Safety and Efficacy of Using the O-Arm Intraoperative Imaging System for Deep Brain Stimulation Lead Implantation.

INTRODUCTION: Accurate electrode implantation is a major goal of deep brain stimulation (DBS) surgery. Intraoperative physiology with microelectrode recording (MER) is routinely used to refine stereotactic accuracy during awake electrode implantation. Recently, portable imaging systems such as the O-arm have become widely available and can be used in isolation or in association with MER to guide DBS lead placement. The aim of this study was to evaluate how the routine use of the O-arm affected DBS surgery safety, efficiency, and outcomes. METHODS: Two cohorts of patients with Parkinson's disease who underwent MER-guided awake subthalamic DBS lead implantation with and without O-arm were compared. We examined the total number of microelectrode and macroeletrode passes during each surgery, procedure duration, surgical complications, lead revisions, and motor outcomes. RESULTS: A total of 50 procedures in 41 unique patients were analyzed, of which 26 were performed without O-arm and 24 performed without the O-arm. The mean number of microelectrode passes was 2.46 (SD = 0.99) in the group without O-arm utilization, compared to 1.29 (SD = 0.75) in the group with O-arm usage (p < 0.001). A significant reduction was also found in procedure duration (p = 0.016). No differences were found in motor outcomes between groups. CONCLUSION: The use of the O-arm during DBS lead implantation was associated with significantly fewer brain cannulations for microelectrode recording as well as reduced surgical time.

Early outcomes after intrathecal baclofen therapy in ambulatory patients with multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is a chronic autoimmune disease that causes demyelination and axonal loss. Walking difficulties are a common and debilitating symptom of MS; they are usually caused by spastic paresis of the lower extremities. Although intrathecal baclofen (ITB) therapy has been reported to be an effective treatment for spasticity in MS, there is limited published evidence regarding its effects on ambulation. The goal of this study was to characterize ITB therapy outcomes in ambulatory patients with MS. METHODS: Data from 47 ambulatory patients with MS who received ITB therapy were analyzed retrospectively. Outcome measures included Modified Ashworth Scale, Spasm Frequency Scale, Numeric Pain Rating Scale, and the Timed 25-Foot Walk. Repeated-measures ANOVA was used to test for changes in outcome measures between baseline and posttreatment (6 months and 1 year). Significance was set at p < 0.05. Descriptive data are expressed as the mean ± SD, and results of the repeated-measures ANOVA tests and the Wilcoxon rank-sum test are expressed as the mean ± SEM. RESULTS: There was a statistically significant reduction in the following variables: 1) aggregate lower-extremity Modified Ashworth Scale scores (from 14.8 ± 1.0 before ITB therapy to 5.8 ± 0.8 at 6 months posttreatment and 6.4 ± 0.9 at 1 year [p < 0.05]); 2) Numeric Pain Rating Scale scores (4.4 ± 0.5 before ITB, 2.8 ± 0.5 at 6 months, and 2.4 ± 0.4 at 1 year [p < 0.05]); 3) spasm frequency (45.7% of the patients reported a spasm frequency of ≥ 1 event per hour before ITB therapy, whereas 15.6% and 4.3% of the patients reported the same at 6 months and 1 year posttreatment, respectively [p < 0.05]); and 4) the number of oral medications taken for spasticity (p < 0.05). Of the 47 patients, 34 remained ambulatory at 6 months, and 32 at 1 year posttreatment. There was no statistically significant change in performance on the Timed 25-Foot Walk test over time for those patients who remained ambulatory. CONCLUSIONS: In this retrospective study, the authors found that ITB therapy is effective in reducing spasticity and related symptoms in ambulatory patients with MS. Because the use of ITB therapy is increasing in ambulatory patients with MS, randomized, prospective studies are important to help provide a more useful characterization of the effects of ITB therapy on ambulation.

Subsequent Pulse Generator Replacement Surgery Does Not Increase the Infection Rate in Patients With Deep Brain Stimulator Systems: A Review of 1537 Unique Implants at a Single Center.

INTRODUCTION: Deep brain stimulation (DBS) is a well-recognized treatment for patients with movement disorders and other neurological diseases. The implantable pulse generator (IPG) is a fundamental component of the DBS system. Although IPG implantation and replacement surgeries are comparatively minor procedures relative to the brain lead insertion, patients often require multiple IPG replacements during their lifetime with each operation carrying a small but possibly cumulative risk of complications. To better educate our patients and improve surgical outcomes, we reviewed our series of patients at our institution. METHODS: Using electronic health record data, we retrospectively reviewed all initial and subsequent IPG surgeries from patients who underwent at least one IPG surgery between the years of 2010 and 2015 at the Cleveland Clinic main campus. We calculated infection rates for initial IPG implantation surgeries and the infection rate for subsequent replacements. Fisher's exact tests were used to evaluate the chance of an infection between the initial implantation and replacement. Fisher's exact tests and simple logistic regression analyses were used to determine the predictive ability of selected demographic and clinical variables RESULTS: Our final sample included 697 patients and 1537 surgeries. For all patients, the infection rate at the first surgery was 2.01%; at the second surgery, it was 0.44%; and at the third surgery, it was 1.83%. When considering only patients that underwent at least three replacement surgeries (n = 114) the infection rate did not change in a significant manner with subsequent interventions compared to the first replacement. No other variable of interest was a significant predictor of infection. CONCLUSION: We did not find increasing rates of infection with subsequent IPG replacement procedures.

Effects of chronic alcohol consumption on long-term outcomes of thalamic deep brain stimulation for essential tremor.

The prevalence of essential tremor (ET) is about 4% above 40years of age. Chronic alcohol consumption is present in around 20% of patients with ET. Our objective was to identify whether chronic alcohol consumption was associated with a negative effect on tremor outcome after thalamic deep brain stimulation (DBS) in ET patients. We conducted a retrospective chart review, from January 2005 to December 2012, from which 23 patients who had ventral intermediate nucleus (Vim)-DBS surgery for ET were identified. Seven patients had a positive history of chronic alcohol consumption. We defined as chronic alcohol users those patients with a habit of drinking alcohol every day in order to suppress tremor. In the overall group of 23 patients, there was a reduction in the median tremor score from 8 pre-operatively, to 1 post-operatively (p<0.0001). The alcohol consumers group experienced a reduction in the median tremor score from 6 pre-operatively to 0 post-operatively (p=0.03). The non-alcohol consumers group had a reduction in the median tremor score from 8 pre-operatively to 1.7 post-operatively (p<0.0001). Both groups of patients experienced significant benefit from thalamic DBS. A larger study may reveal statistically significant differences between subgroups.

Medical student education in neurosurgery: optional or essential?

ISSUE: Current medical school curricula emphasize general practice principles, and this has led predictably to increasingly limited exposure to subspecialties, including neurosurgery. However, a significant amount of neurosurgical disease and/or emergencies present in primary care settings or emergency rooms. In light of an already acknowledged shortage of neurosurgery providers, this means that general practitioners should be well educated and prepared to diagnose and manage neurosurgical disease. Considering the devastating consequences of a missed or delayed neurosurgical diagnosis, limiting future physicians' exposure to the field of neurosurgery is not in the best interests of the patient. EVIDENCE: In this article, the authors review and discuss the results of several studies investigating the prevalence, presentation, diagnosis, and management of neurosurgical disease in emergency and general practice settings. They then discuss the current status of neurosurgical education in medical schools, both from the educators' and students' perspectives, and how this status might impact patient care. Finally, they offer suggestions for the improvement of neurosurgical education during medical school. IMPLICATIONS: Despite being considered highly subspecialized, neurosurgical diagnosis and care is a field in which all physicians should receive proper education and training. To properly serve patients and produce competent physicians, steps should be taken to re-emphasize the importance of neurosurgical education for medical students.

Preserving cortico-striatal function: deep brain stimulation in Huntington's disease.

Huntington's disease (HD) is an incurable neurodegenerative disease characterized by the triad of chorea, cognitive dysfunction and psychiatric disturbances. Since the discovery of the HD gene, the pathogenesis has been outlined, but to date a cure has not been found. Disease modifying therapies are needed desperately to improve function, alleviate suffering, and provide hope for symptomatic patients. Deep brain stimulation (DBS), a proven therapy for managing the symptoms of some neurodegenerative movement disorders, including Parkinson's disease, has been reported as a palliative treatment in select cases of HD with debilitating chorea with variable success. New insights into the mechanism of action of DBS suggest it may have the potential to circumvent other manifestations of HD including cognitive deterioration. Furthermore, because DBS is already widely used, reversible, and has a risk profile that is relatively low, new studies can be initiated. In this article we contend that new clinical trials be considered to test the effects of DBS for HD.

Wireless control of intraspinal microstimulation in a rodent model of paralysis.

OBJECT: Despite a promising outlook, existing intraspinal microstimulation (ISMS) techniques for restoring functional motor control after spinal cord injury are not yet suitable for use outside a controlled laboratory environment. Thus, successful application of ISMS therapy in humans will require the use of versatile chronic neurostimulation systems. The objective of this study was to establish proof of principle for wireless control of ISMS to evoke controlled motor function in a rodent model of complete spinal cord injury. METHODS: The lumbar spinal cord in each of 17 fully anesthetized Sprague-Dawley rats was stimulated via ISMS electrodes to evoke hindlimb function. Nine subjects underwent complete surgical transection of the spinal cord at the T-4 level 7 days before stimulation. Targeting for both groups (spinalized and control) was performed under visual inspection via dorsal spinal cord landmarks such as the dorsal root entry zone and the dorsal median fissure. Teflon-insulated stimulating platinum-iridium microwire electrodes (50 µm in diameter, with a 30- to 60-µm exposed tip) were implanted within the ventral gray matter to an approximate depth of 1.8 mm. Electrode implantation was performed using a free-hand delivery technique (n = 12) or a Kopf spinal frame system (n = 5) to compare the efficacy of these 2 commonly used targeting techniques. Stimulation was controlled remotely using a wireless neurostimulation control system. Hindlimb movements evoked by stimulation were tracked via kinematic markers placed on the hips, knees, ankles, and paws. Postmortem fixation and staining of the spinal cord tissue were conducted to determine the final positions of the stimulating electrodes within the spinal cord tissue. RESULTS: The results show that wireless ISMS was capable of evoking controlled and sustained activation of ankle, knee, and hip muscles in 90% of the spinalized rats (n = 9) and 100% of the healthy control rats (n = 8). No functional differences between movements evoked by either of the 2 targeting techniques were revealed. However, frame-based targeting required fewer electrode penetrations to evoke target movements. CONCLUSIONS: Clinical restoration of functional movement via ISMS remains a distant goal. However, the technology presented herein represents the first step toward restoring functional independence for individuals with chronic spinal cord injury.

Restoration of motor function following spinal cord injury via optimal control of intraspinal microstimulation: toward a next generation closed-loop neural prosthesis.

Movement is planned and coordinated by the brain and carried out by contracting muscles acting on specific joints. Motor commands initiated in the brain travel through descending pathways in the spinal cord to effector motor neurons before reaching target muscles. Damage to these pathways by spinal cord injury (SCI) can result in paralysis below the injury level. However, the planning and coordination centers of the brain, as well as peripheral nerves and the muscles that they act upon, remain functional. Neuroprosthetic devices can restore motor function following SCI by direct electrical stimulation of the neuromuscular system. Unfortunately, conventional neuroprosthetic techniques are limited by a myriad of factors that include, but are not limited to, a lack of characterization of non-linear input/output system dynamics, mechanical coupling, limited number of degrees of freedom, high power consumption, large device size, and rapid onset of muscle fatigue. Wireless multi-channel closed-loop neuroprostheses that integrate command signals from the brain with sensor-based feedback from the environment and the system's state offer the possibility of increasing device performance, ultimately improving quality of life for people with SCI. In this manuscript, we review neuroprosthetic technology for improving functional restoration following SCI and describe brain-machine interfaces suitable for control of neuroprosthetic systems with multiple degrees of freedom. Additionally, we discuss novel stimulation paradigms that can improve synergy with higher planning centers and improve fatigue-resistant activation of paralyzed muscles. In the near future, integration of these technologies will provide SCI survivors with versatile closed-loop neuroprosthetic systems for restoring function to paralyzed muscles.

Long-term outcomes after replacement of percutaneous leads with paddle leads in a retrospective cohort of patients with spinal cord stimulation systems.

BACKGROUND: Although the long-term outcomes for spinal cord stimulation (SCS) have been reported, long-term outcomes of patients who underwent revisions of the SCS with paddle leads are lacking. OBJECTIVE: To report the long-term outcomes of 39 patients who had percutaneous SCS revised with a new paddle lead. METHODS: Baseline and follow-up mail-in questionnaires assessed pain and disability levels with numerical rating scales, somatotopical overlap between SCS-related paresthesias and areas of chronic pain, and overall satisfaction. Analysis was performed with regard to age, sex, diagnosis, duration of disease, number of surgical revisions, complications, and interval between surgeries. RESULTS: After surgical revision, 20 patients (50%) had at least a 3-point reduction in the numerical rating scale. Greater pain reduction was correlated with better coverage (P = .001). Coverage area was greater in patients with a single revision than in patients with multiple revisions (P = .01). Good satisfaction was reported by 25 patients (62.5%) who indicated that they would undergo the procedure again in order to achieve the same results. These patients had significantly greater pain reduction (P = .001) and better coverage (P = .002) than patients who reported otherwise. No other major complication occurred. CONCLUSION: Revision of percutaneous SCS systems with implantation of a new paddle lead is safe and more effective in patients who have undergone not more than 1 prior revision.

Brain machine interface and limb reanimation technologies: restoring function after spinal cord injury through development of a bypass system.

Functional restoration of limb movement after traumatic spinal cord injury (SCI) remains the ultimate goal in SCI treatment and directs the focus of current research strategies. To date, most investigations in the treatment of SCI focus on repairing the injury site. Although offering some promise, these efforts have met with significant roadblocks because treatment measures that are successful in animal trials do not yield similar results in human trials. In contrast to biologic therapies, there are now emerging neural interface technologies, such as brain machine interface (BMI) and limb reanimation through electrical stimulators, to create a bypass around the site of the SCI. The BMI systems analyze brain signals to allow control of devices that are used to assist SCI patients. Such devices may include a computer, robotic arm, or exoskeleton. Limb reanimation technologies, which include functional electrical stimulation, epidural stimulation, and intraspinal microstimulation systems, activate neuronal pathways below the level of the SCI. We present a concise review of recent advances in the BMI and limb reanimation technologies that provides the foundation for the development of a bypass system to improve functional outcome after traumatic SCI. We also discuss challenges to the practical implementation of such a bypass system in both these developing fields.

Large animal model for development of functional restoration paradigms using epidural and intraspinal stimulation.

Restoration of movement following spinal cord injury (SCI) has been achieved using electrical stimulation of peripheral nerves and skeletal muscles. However, practical limitations such as the rapid onset of muscle fatigue hinder clinical application of these technologies. Recently, direct stimulation of alpha motor neurons has shown promise for evoking graded, controlled, and sustained muscle contractions in rodent and feline animal models while overcoming some of these limitations. However, small animal models are not optimal for the development of clinical spinal stimulation techniques for functional restoration of movement. Furthermore, variance in surgical procedure, targeting, and electrode implantation techniques can compromise therapeutic outcomes and impede comparison of results across studies. Herein, we present a protocol and large animal model that allow standardized development, testing, and optimization of novel clinical strategies for restoring motor function following spinal cord injury. We tested this protocol using both epidural and intraspinal stimulation in a porcine model of spinal cord injury, but the protocol is suitable for the development of other novel therapeutic strategies. This protocol will help characterize spinal circuits vital for selective activation of motor neuron pools. In turn, this will expedite the development and validation of high-precision therapeutic targeting strategies and stimulation technologies for optimal restoration of motor function in humans.

Simulated spinal cerebrospinal fluid leak repair: an educational model with didactic and technical components.

BACKGROUND: In the era of surgical resident work hour restrictions, the traditional apprenticeship model may provide fewer hours for neurosurgical residents to hone technical skills. Spinal dura mater closure or repair is 1 skill that is infrequently encountered, and persistent cerebrospinal fluid leaks are a potential morbidity. OBJECTIVE: To establish an educational curriculum to train residents in spinal dura mater closure with a novel durotomy repair model. METHODS: The Congress of Neurological Surgeons has developed a simulation-based model for durotomy closure with the ongoing efforts of their simulation educational committee. The core curriculum consists of didactic training materials and a technical simulation model of dural repair for the lumbar spine. RESULTS: Didactic pretest scores ranged from 4/11 (36%) to 10/11 (91%). Posttest scores ranged from 8/11 (73%) to 11/11 (100%). Overall, didactic improvements were demonstrated by all participants, with a mean improvement between pre- and posttest scores of 1.17 (18.5%; P = .02). The technical component consisted of 11 durotomy closures by 6 participants, where 4 participants performed multiple durotomies. Mean time to closure of the durotomy ranged from 490 to 546 seconds in the first and second closures, respectively (P = .66), whereby the median leak rate improved from 14 to 7 (P = .34). There were also demonstrative technical improvements by all. CONCLUSION: Simulated spinal dura mater repair appears to be a potentially valuable tool in the education of neurosurgery residents. The combination of a didactic and technical assessment appears to be synergistic in terms of educational development.

Simulated lumbar minimally invasive surgery educational model with didactic and technical components.

BACKGROUND: The learning and development of technical skills are paramount for neurosurgical trainees. External influences and a need for maximizing efficiency and proficiency have encouraged advancements in simulator-based learning models. OBJECTIVE: To confirm the importance of establishing an educational curriculum for teaching minimally invasive techniques of pedicle screw placement using a computer-enhanced physical model of percutaneous pedicle screw placement with simultaneous didactic and technical components. METHODS: A 2-hour educational curriculum was created to educate neurosurgical residents on anatomy, pathophysiology, and technical aspects associated with image-guided pedicle screw placement. Predidactic and postdidactic practical and written scores were analyzed and compared. Scores were calculated for each participant on the basis of the optimal pedicle screw starting point and trajectory for both fluoroscopy and computed tomographic navigation. RESULTS: Eight trainees participated in this module. Average mean scores on the written didactic test improved from 78% to 100%. The technical component scores for fluoroscopic guidance improved from 58.8 to 52.9. Technical score for computed tomography-navigated guidance also improved from 28.3 to 26.6. CONCLUSION: Didactic and technical quantitative scores with a simulator-based educational curriculum improved objectively measured resident performance. A minimally invasive spine simulation model and curriculum may serve a valuable function in the education of neurosurgical residents and outcomes for patients.

Developing a neurosurgical simulation-based educational curriculum: an overview.

BACKGROUND: The science of medicine has undergone rapid advancement and expansion as a result of significant technological innovations, and this has affected the training of neurosurgical residents. OBJECTIVE: To develop a simulation-based neurosurgical educational curriculum to improve resident education. METHODS: The Congress of Neurological Surgeons established a Simulation Committee to explore the use of this technology in maximizing neurosurgical education. Simulators were incorporated into an educational curriculum with both a didactic and a technical component. The simulators and didactic portions were validated with objective pretests and posttests. RESULTS: The Simulator Committee has continued to expand the use of simulators in neurosurgical education and has organized several practical courses. The simulator use continues to expand into vasculature, spinal, and cranial modules. Each module has independently shown improved training scores in both didactic and technical skills. CONCLUSION: The Congress of Neurological Surgeons has successfully incorporated simulation into an educational curriculum with both didactic and technical components. This appears to be a powerful educational tool, and its uses are being further expanded.