Uncovering the rate and risk factors of intrathecal baclofen pump-associated complications in the adult population.

OBJECTIVE: The aim of this study was 1) to describe the rate of intrathecal baclofen (ITB)-associated complications at a large tertiary center, and 2) to evaluate the impact of patient-related factors on the likelihood of developing such complications. METHODS: A retrospective single-center study was carried out. A total of 301 eligible patients were included in the analysis. Univariate regression models were used to evaluate the impact of age, sex, diagnosis, ambulation status, modified Ashworth scale score, body mass index, diabetes status, and pain level on the likelihood of developing a device-related infection, pump malfunction, catheter malfunction, and other clinically significant complications. RESULTS: Overall, 27% of patients experienced an ITB-related complication. The most common complications included infection (6%, 18/301), pump malfunction (7.3%, 22/301), and catheter malfunction (14%, 42/301). The univariate analyses revealed that the patient's ambulatory status had a significant impact on the likelihood of developing a catheter-related malfunction. Furthermore, a trend toward significance was identified between patients' preoperative body mass index and device-related infection. Finally, the risk of suffering any ITB-related complications was statistically correlated with the number of years that had passed since the initial pump implantation. CONCLUSIONS: The authors' analysis reveals a previously underrecognized association between ambulatory status at the time of ITB pump implantation and the incidence of catheter-related complications, and confirms the impact of time since surgery on the risk of developing any ITB-related complication. The patient's age, sex, diagnosis, diabetes status, or pain level at baseline were not associated with the risk of complications. Collectively, these insights contribute novel information to the existing literature, providing practical value for physicians in guiding patient selection for ITB therapy.

Loss of Efficacy in Ventral Intermediate Nucleus Stimulation for Essential Tremor.

OBJECTIVE: The primary aim of this study is to report long-term outcomes associated with deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) performed at our institution. We further aimed to elicit the factors associated with loss of efficacy and to discuss the need for exploring and establishing reliable rescue targets. METHODS: To study long-term outcomes, we performed a retrospective chart review and extracted tremor scores of 43 patients who underwent VIM DBS lead implantation for essential tremor at our center. We further evaluated factors that could influence outcomes over time, including demographics, body mass index, duration of follow-up, degree of parenchymal atrophy indexed by the global cortical atrophy scale, and third ventricular width. RESULTS: In this cohort, tremor scores on the latest follow-up (median 52.7 months) were noted to be worse than initial postoperative scores in 56% of DBS leads. Furthermore, 14% of leads were associated with clinically significant loss of benefit. Factors including the length of time since the lead implantation, age at the time of surgery, sex, body mass index, preoperative atrophy, and third ventricular width were not predictive of long-term outcomes. CONCLUSIONS: Our study identified a substantial subgroup of VIM-DBS patient who experienced a gradual decline in treatment efficacy over time. We propose that this phenomenon can be attributed primarily to habituation and disease progression. Furthermore, we discuss the need to establish reliable and effective rescue targets for this subpopulation of patients, with ventral-oralis complex and dentate nucleus emerging as potential candidates.

Thalamic deep brain stimulation in traumatic brain injury: a phase 1, randomized feasibility study.

Converging evidence indicates that impairments in executive function and information-processing speed limit quality of life and social reentry after moderate-to-severe traumatic brain injury (msTBI). These deficits reflect dysfunction of frontostriatal networks for which the central lateral (CL) nucleus of the thalamus is a critical node. The primary objective of this feasibility study was to test the safety and efficacy of deep brain stimulation within the CL and the associated medial dorsal tegmental (CL/DTTm) tract.Six participants with msTBI, who were between 3 and 18 years post-injury, underwent surgery with electrode placement guided by imaging and subject-specific biophysical modeling to predict activation of the CL/DTTm tract. The primary efficacy measure was improvement in executive control indexed by processing speed on part B of the trail-making test.All six participants were safely implanted. Five participants completed the study and one was withdrawn for protocol non-compliance. Processing speed on part B of the trail-making test improved 15% to 52% from baseline, exceeding the 10% benchmark for improvement in all five cases.CL/DTTm deep brain stimulation can be safely applied and may improve executive control in patients with msTBI who are in the chronic phase of recovery.ClinicalTrials.gov identifier: NCT02881151 .

Myogenic and cortical evoked potentials vary as a function of stimulus pulse geometry delivered in the subthalamic nucleus of Parkinson's disease patients.

Introduction: The therapeutic efficacy of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease (PD) may be limited for some patients by the presence of stimulation-related side effects. Such effects are most often attributed to electrical current spread beyond the target region. Prior computational modeling studies have suggested that changing the degree of asymmetry of the individual phases of the biphasic, stimulus pulse may allow for more selective activation of neural elements in the target region. To the extent that different neural elements contribute to the therapeutic vs. side-effect inducing effects of DBS, such improved selectivity may provide a new parameter for optimizing DBS to increase the therapeutic window. Methods: We investigated the effect of six different pulse geometries on cortical and myogenic evoked potentials in eight patients with PD whose leads were temporarily externalized following STN DBS implant surgery. DBS-cortical evoked potentials were quantified using peak to peak measurements and wavelets and myogenic potentials were quantified using RMS. Results: We found that the slope of the recruitment curves differed significantly as a function of pulse geometry for both the cortical- and myogenic responses. Notably, this effect was observed most frequently when stimulation was delivered using a monopolar, as opposed to a bipolar, configuration. Discussion: Manipulating pulse geometry results in differential physiological effects at both the cortical and neuromuscular level. Exploiting these differences may help to expand DBS' therapeutic window and support the potential for incorporating pulse geometry as an additional parameter for optimizing therapeutic benefit.

Intracranial Bleeding in Deep Brain Stimulation Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Deep brain stimulation (DBS) is a neurosurgical treatment used for the treatment of movement disorders. Surgical and perioperative complications, although infrequent, can result in clinically significant neurological impairment. OBJECTIVES: In this study, we evaluated the incidence and risk factors of intracranial bleeding in DBS surgery. METHOD: Medline, EMBASE, and Cochrane were screened in line with PRISMA 2020 guidelines to capture studies reporting on the incidence of hemorrhagic events in DBS. After removing duplicates, the search yielded 1,510 papers. Abstracts were evaluated by two independent reviewers for relevance. A total of 386 abstracts progressed to the full-text screen and were assessed against eligibility criteria. A total of 151 studies met the criteria and were included in the analysis. Any disagreement between the reviewers was resolved by consensus. Relevant data points were extracted and analyzed in OpenMeta [Analyst] software. RESULTS: The incidence of intracranial bleeding was 2.5% (95% CI: 2.2-2.8%) per each patient and 1.4% (95% CI: 1.2-1.6%) per each implanted lead. There was no statistically significant difference across implantation targets and clinical indications. Patients who developed an intracranial bleed were on average 5 years older (95% CI: 1.26-13.19), but no difference was observed between the genders (p = 0.891). A nonsignificant trend was observed for a higher risk of bleeding in patients with hypertension (OR: 2.99, 95% CI: 0.97-9.19) (p = 0.056). The use of microelectrode recording did not affect the rate of bleeding (p = 0.79). CONCLUSIONS: In this review, we find that the rate of bleeding per each implanted lead was 1.4% and that older patients had a higher risk of hemorrhage.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Neuroablative Procedures for Patients With Cancer Pain.

BACKGROUND: Managing cancer pain once it is refractory to conventional treatment continues to challenge caregivers committed to serving those who are suffering from a malignancy. Although neuromodulation has a role in the treatment of cancer pain for some patients, these therapies may not be suitable for all patients. Therefore, neuroablative procedures, which were once a mainstay in treating intractable cancer pain, are again on the rise. This guideline serves as a systematic review of the literature of the outcomes following neuroablative procedures. OBJECTIVE: To establish clinical practice guidelines for the use of neuroablative procedures to treat patients with cancer pain. METHODS: A systematic review of neuroablative procedures used to treat patients with cancer pain from 1980 to April 2019 was performed using the United States National Library of Medicine PubMed database, EMBASE, and Cochrane CENTRAL. After inclusion criteria were established, full text articles that met the inclusion criteria were reviewed by 2 members of the task force and the quality of the evidence was graded. RESULTS: In total, 14 646 relevant abstracts were identified by the literature search, from which 189 met initial screening criteria. After full text review, 58 of the 189 articles were included and subdivided into 4 different clinical scenarios. These include unilateral somatic nociceptive/neuropathic body cancer pain, craniofacial cancer pain, midline subdiaphragmatic visceral cancer pain, and disseminated cancer pain. Class II and III evidence was available for these 4 clinical scenarios. Level III recommendations were developed for the use of neuroablative procedures to treat patients with cancer pain. CONCLUSION: Neuroablative procedures may be an option for treating patients with refractory cancer pain. Serious adverse events were reported in some studies, but were relatively uncommon. Improved imaging, refinements in technique and the availability of new lesioning modalities may minimize the risks of neuroablation even further.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/guidelines-on-neuroablative-procedures-patients-wi.

Long-term outcomes of intrathecal baclofen in ambulatory multiple sclerosis patients: A single-center experience.

BACKGROUND: Intrathecal baclofen (ITB) is traditionally reserved for non-ambulatory patients. OBJECTIVE: To investigate outcomes of ITB in ambulatory multiple sclerosis (MS) patients. METHODS: Changes in outcome measures were estimated by a mixed effect model, while the complication rate was calculated using a logistic regression. Predictors of non-ambulatory status were identified by Cox model. RESULTS: In all, 256 patients received an ITB test injection and 170 underwent ITB surgery. Aggregate Modified Ashworth Scale (MAS) scores for the ambulatory ITB cohort decreased from 13.5 ± 6.96 to 4.54 ± 4.18 at 5 years (p < 0.001). There was no significant change in walking speed 1 year post ITB surgery (0.45 m/second ± 0.30 vs 0.38 m/second ± 0.39, p = 0.80) with 77.8% of patients remaining ambulatory which decreased to 41.7% at year 5. Longer MS disease duration (hazard ratio (HR): 1.04; 95% confidence interval (CI): 1.01-1.07; p = 0.018) and lower hip flexor strength (HR: 0.40; 95% CI: 0.27-0.57; p < 0.001) predicted non-ambulatory status after surgery. Complications were more likely in the ambulatory cohort (odds ratio (OR): 3.30, 95% CI: 2.17-5.02; p = 0.017). CONCLUSION: ITB is effective for ambulatory MS patients without compromising short-term walking speed, although a higher complication rate was observed in this cohort.

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.

Feasibility and performance of a frameless stereotactic system for targeting subcortical nuclei in nonhuman primates.

OBJECTIVE: Deep brain stimulation (DBS) is an effective therapy for different neurological diseases, despite the lack of comprehension of its mechanism of action. The use of nonhuman primates (NHPs) has been historically important in advancing this field and presents a unique opportunity to uncover the therapeutic mechanisms of DBS, opening the way for optimization of current applications and the development of new ones. To be informative, research using NHPs should make use of appropriate electrode implantation tools. In the present work, the authors report on the feasibility and accuracy of targeting different deep brain regions in NHPs using a commercially available frameless stereotactic system (microTargeting platform). METHODS: Seven NHPs were implanted with DBS electrodes, either in the subthalamic nucleus or in the cerebellar dentate nucleus. A microTargeting platform was designed for each animal and used to guide implantation of the electrode. Imaging studies were acquired preoperatively for each animal, and were subsequently analyzed by two independent evaluators to estimate the electrode placement error (EPE). The interobserver variability was assessed as well. RESULTS: The radial and vector components of the EPE were estimated separately. The magnitude of the vector of EPE was 1.29 ± 0.41 mm and the mean radial EPE was 0.96 ± 0.63 mm. The interobserver variability was considered negligible. CONCLUSIONS: These results reveal the suitability of this commercial system to enhance the surgical insertion of DBS leads in the primate brain, in comparison to rigid traditional frames. Furthermore, our results open up the possibility of performing frameless stereotaxy in primates without the necessity of relying on expensive methods based on intraoperative imaging.

Predictors of second-sided deep brain stimulation for Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a progressive neurological movement disorder that is commonly treated with deep brain stimulation (DBS) surgery in advanced stages. The purpose of this study was to investigate factors that affect time to placement of a second-sided DBS lead for PD when a unilateral lead is initially placed for asymmetrical presentation. The decision whether to initially perform unilateral or bilateral DBS is largely based on physician and/or patient preference. METHODS: This study was a retrospective cohort analysis of patients with PD undergoing initial unilateral DBS for asymmetrical disease between January 1999 and December 2017 at the authors' institution. Patients treated with DBS for essential tremor or other conditions were excluded. Variables collected included demographics at surgery, time since diagnosis, Unified Parkinson's Disease Rating Scale motor scores (UPDRS-III), patient-reported quality-of-life outcomes, side of operation, DBS target, intraoperative complications, and date of follow-up. Paired t-tests were used to assess mean changes in UPDRS-III. Cox proportional hazards analysis and the Kaplan-Meier method were used to determine factors associated with time to second lead insertion over 5 years. RESULTS: The final cohort included 105 patients who underwent initial unilateral DBS for asymmetrical PD; 59% of patients had a second-sided lead placed within 5 years with a median time of 34 months. Factors found to be significantly associated with early second-sided DBS included patient age 65 years or younger, globus pallidus internus (GPi) target, and greater off-medication reduction in UPDRS-III score following initial surgery. Older age was also found to be associated with a smaller preoperative UPDRS-III levodopa responsiveness score and with a smaller preoperative to postoperative medication-off UPDRS-III change. CONCLUSIONS: Younger patients, those undergoing GPi-targeted unilateral DBS, and patients who responded better to the initial DBS were more likely to undergo early second-sided lead placement. Therefore, these patients, and patients who are more responsive to medication preoperatively (as a proxy for DBS responsiveness), may benefit from consideration of initial bilateral DBS.

Cortical thickness in visuo-motor areas is related to motor outcomes after STN DBS for Parkinson's disease.

INTRODUCTION: Deep brain stimulation (DBS) is a widely accepted therapy for Parkinson's disease. While outcome predictors such as levodopa-response are well established, there remains a need for objective and unbiased predictors in clinical practice. We performed an exploratory study to examine whether cortical thickness, derived from preoperative MRI, correlates with postoperative outcome. METHODS: Using freesurfer, we retrospectively measured cortical thickness on the preoperative MRI of 38 patients who underwent bilateral STN-DBS for PD during a 4-year period. The Unified Parkinson Disease Rating motor (UPDRS III) and experiences of daily living subscales (UPDRS II) were collected at baseline and six months after surgery. As an initial analysis, a series of partial correlations was conducted to evaluate the association between postoperative outcome scores and average cortical thickness from predefined regions of interest, adjusting for candidate confounders, without correcting for multiple comparisons. A confirmatory vertex-wise analysis was performed using a cluster-wise correction for multiple comparisons. RESULTS: Based on the ROI analysis, the strongest correlation with motor outcome was found to be with the left lateral-occipital cortex. Patients with greater cortical thickness in this area presented with greater improvements in motor scores. This relationship was also supported by the vertex-wise analysis. Greater cortical thickness in frontal and temporal regions may be correlated with greater post-operative improvements in UPDRS II, but this was not confirmed in the vertex-wise analysis. CONCLUSIONS: Our data indicate that greater cortical thickness in visuo-motor areas is correlated with motor outcomes after DBS for PD. Further prospective investigations are needed to confirm our findings and better-investigate potential image biomarkers.

Patient-Specific Analysis of Neural Activation During Spinal Cord Stimulation for Pain.

OBJECTIVE: Despite the widespread use of spinal cord stimulation (SCS) for chronic pain management, its neuromodulatory effects remain poorly understood. Computational models provide a valuable tool to study SCS and its effects on axonal pathways within the spinal cord. However, these models must include sufficient detail to correlate model predictions with clinical effects, including patient-specific data. Therefore, the goal of this study was to investigate axonal activation at clinically relevant SCS parameters using a computer model that incorporated patient-specific anatomy and electrode locations. METHODS: We developed a patient-specific computer model for a patient undergoing SCS to treat chronic pain. This computer model consisted of two main components: 1) finite element model of the extracellular voltages generated by SCS and 2) multicompartment cable models of axons in the spinal cord. To determine the potential significance of a patient-specific approach, we also performed simulations with standard canonical models of SCS. We used the computer models to estimate axonal activation at clinically measured sensory, comfort, and discomfort thresholds. RESULTS: The patient-specific and canonical models predicted significantly different axonal activation. Relative to the canonical models, the patient-specific model predicted sensory threshold estimates that were more consistent with the corresponding clinical measurements. These results suggest that it is important to account for sources of interpatient variability (e.g., anatomy, electrode locations) in model-based analysis of SCS. CONCLUSIONS: This study demonstrates the potential for patient-specific computer models to quantitatively describe the axonal response to SCS and to address scientific questions related to clinical SCS.

Electrophysiologic mapping for deep brain stimulation for movement disorders.

Electrophysiologic mapping remains an integral component of deep brain stimulation (DBS) surgical procedures, particularly in movement disorder cases where functional maps are used to guide DBS lead placement in patients with Parkinson's disease, dystonia, or tremor. Overall, the goal of the surgical procedure is to implant the distal end of a chronic, multicontact depth electrode into a specific brain region for the purpose of delivering therapeutic electrical stimulation. Regions that are currently targeted for patients with movement disorders include the subthalamic nucleus, the ventral intermediate nucleus of the thalamus, and the globus pallidus. Multiple imaging modalities are used initially to derive a stereotactic plan and guide the initial microelectrode trajectory. Changes in neuronal firing rate and pattern, both spontaneous and in response to somatosensory stimulation, are used to establish the location of the tip of the microelectrode(s), while acute stimulation can be used to estimate the proximity of neighboring brain regions. In this chapter, we will provide an overview of the microelectrode recording process as it is commonly applied to refine image-based targeting of lead placement for DBS surgery.

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.

Durotomy Surrogate and Seals for Intradural Spinal Cord Stimulators: Apparatus and Review of Clinical Methods and Materials.

INTRODUCTION: We are developing a novel intradural spinal cord stimulator for treatment of neuropathic pain and spasticity. A key feature is the means by which it seals the dura mater to prevent leakage of cerebrospinal fluid (CSF). We have built and employed a test rig that enables evaluation of candidate seal materials. METHODS: To guide the design of the test rig, we reviewed the literature on neurosurgical durotomies. The test rig has a mock durotomy slot with a dural substitute serving as the surrogate dura mater and water as the CSF. The primary experimental goal was to evaluate the effectiveness of candidate gasket materials as seals against CSF leakage in an implanted prototype device, at both normal and super-physiologic pressures. A secondary goal was to measure the transmembrane flows in a representative dural substitute material, to establish its baseline aqueous transport properties. RESULTS: The seals prevented leakage of water at the implantation site over periods of ≈ ten days, long enough for the scar tissue to form in the clinical situation. The seals also held at water pressure transients approaching 250 mm Hg. The residual volumetric flux of water through the dura substitute membrane (Durepair®) was δVT /A ≈ 0.24 mm3 /min/cm2 , consistent with expectations for transport through the porous membrane prior to closure and equalization of internal/external pressures. CONCLUSIONS: We have demonstrated the workability of obtaining robust seal against leakage at the implantation site of a novel intradural stimulator using a custom-designed test rig. Extension of the method to in vivo testing in a large animal model will be the next step.

Patient-reported allergies predict postoperative outcomes and psychosomatic markers after spine surgery.

BACKGROUND CONTEXT: Prior studies have shown that patient-reported allergies can be prognostic of poorer postoperative outcomes. PURPOSE: The objective of this study was to investigate the correlation between self-reported allergies and outcomes after cervical or lumbar spine surgery. STUDY DESIGN/SETTING: This is a retrospective cohort study at a single tertiary care institution. PATIENT SAMPLE: The patient sample included all patients undergoing cervical or lumbar spine surgery from 2009 to 2014. OUTCOME MEASURES: The primary outcome measure was change in the EuroQol-5 Dimensions (EQ-5D) after surgery. Secondary outcomes included changes in the Pain Disability Questionnaire (PDQ) and in the Patient Health Questionnaire-9 (PHQ-9), achievement of the minimal clinically important difference (MCID) in these measures, and cost of admission. METHODS: Before and after surgery, EQ-5D, PDQ, and PHQ-9 were recorded for patients with available data. Paired Student t tests were used to compare changes in these measures after surgery. Multivariable linear and logistic regressions were used to assess the relationship between the log transformation of the total number of allergies and outcomes. RESULTS: A total of 592 cervical patients and 4,465 lumbar patients were included. The median number of reported allergies was two. The EQ-5D index increased from 0.539 to 0.703 for cervical patients and from 0.530 to 0.676 for lumbar patients (p<.01 for both). Patients experienced significant pain improvement by the PDQ (80.1-58.2 for cervical patients and 79.4-58.1 for lumbar patients, p<.01). Using multivariable logistic regression, the log transformation of the number of allergies predicted significantly higher odds of achieving the PDQ MCID (odds ratio [OR]=2.09, 95% confidence interval [CI] 1.05-4.15, p=.02, for cervical patients; OR=1.30, 95% CI 1.03-1.68, p=.03, for lumbar patients). However, this relationship was not durable for patients with follow-up exceeding 1 year. The log transformation of the number of allergies for lumbar patients predicted a significantly increased cost of admission (ß=$3,597, p<.01) and trended toward significance among cervical patients (ß=$1,842, p=.10). CONCLUSIONS: Patient-reported allergies correlate with subjective improvement in pain and disability after spine surgery and may serve as a marker of postoperative outcomes. The relationship between allergies and PDQ improvement may be secondary to the short-term expectation-actuality discrepancy, as this relationship was not durable beyond 1 year.

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.

Removal of Intrathecal Catheters Used in Drug Delivery Systems.

INTRODUCTION: Implanted intrathecal drug delivery systems (IDDS) are increasingly used in the treatment of spasticity and in patients with refractory pain. Literature discussing complications associated with intrathecal pump placement is widely available. However, reports of complications following the removal of chronically placed catheters are scarce. We reviewed our series of patients who had surgery to remove the intrathecal catheter. METHODS: Retrospective review was performed for all patients who underwent surgery to remove a catheter linked to an IDDS between 2010 and 2016. Patients older than 18 years were included in final analysis. Demographic (including age at removal, sex, BMI, and comorbidities) and etiologic characteristics (indications of IDDS implant and explant, interval between implant and explant, and concomitant surgery) were analyzed. Simple logistic regression was performed to seek any potential predictor of complications. RESULTS: Fifty-nine patients underwent removal of their intrathecal catheter after variable periods (mean interval of 189 months). On eight occasions, patients developed complications after catheter removal (mean interval between implant and explant was 76 months for these cases). Retained catheter was the cause of complications in half of these occasions. Persistent cerebrospinal fluid leak was the next most common complication, with requirement of an external ventricular drain and lumbar drain to facilitate wound healing on two separate occasions. CONCLUSION: Removal of an intrathecal catheter from IDDS systems may cause complications that in some cases require additional surgery.

Occlusion of the Ascenda Catheter in a Patient with Pump Twiddler's Sydrome: A Case Report.

INTRODUCTION: Intrathecal baclofen (ITB) therapy is an effective way to manage spasticity in numerous conditions, including multiple sclerosis, stroke, and cerebral palsy. While pump failure is a common complication of ITB, improvements in device design have led to reduction of complications. In particular, the Ascenda catheter from Medtronic, Inc. was designed to resist kinking and associated complications; indeed, no incidences of catheter twisting or occlusion have been reported in literature prior to this case. CASE REPORT: We report a case of a 32-year old gentleman who presented to the clinic with symptoms of baclofen withdrawal 19 months after he had a programmable pump implanted for spasticity. During the diagnostic evaluation it was discovered that the patients pump had flipped in his abdominal pocket. He was taken to surgery to reorient the pump, during which time it was noted the catheter was tightly coiled on itself occluding flow. The twisted catheter was excised and replaced with a new segment.His symptoms subsequently resolved. CONCLUSIONS: Although catheter occlusions have subsided since the approval of the Ascenda catheter, pump twiddler's syndrome remains a risk factor for this complication. This is the first report describing this syndrome in a patient with the Ascenda catheter.

Outcomes following deep brain stimulation lead revision or reimplantation for Parkinson's disease.

OBJECTIVEThe number of patients who benefit from deep brain stimulation (DBS) for Parkinson's disease (PD) has increased significantly since the therapy was first approved by the FDA. Suboptimal outcomes, infection, or device failure are risks of the procedure and may require lead removal or repositioning. The authors present here the results of their series of revision and reimplantation surgeries.METHODSThe data were reviewed from all DBS intracranial lead removals, revisions, or reimplantations among patients with PD over a 6-year period at the authors' institution. The indications for these procedures were categorized as infection, suboptimal outcome, and device failure. Motor outcomes as well as lead location were analyzed before removal and after reimplant or revision.RESULTSThe final sample included 25 patients who underwent 34 lead removals. Thirteen patients had 18 leads reimplanted after removal. There was significant improvement in the motor scores after revision surgery among the patients who had the lead revised for a suboptimal outcome (p = 0.025). The mean vector distance of the new lead location compared to the previous location was 2.16 mm (SD 1.17), measured on an axial plane 3.5 mm below the anterior commissure-posterior commissure line. When these leads were analyzed by subgroup, the mean distance was 1.67 mm (SD 0.83 mm) among patients treated for infection and 2.73 mm (SD 1.31 mm) for those with suboptimal outcomes.CONCLUSIONSPatients with PD who undergo reimplantation surgery due to suboptimal outcome may experience significant benefits. Reimplantation after surgical infection seems feasible and overall safe.