Factors Contributing to Spinal Cord Stimulation Outcomes for Chronic Pain.

OBJECTIVE: Spinal cord stimulation (SCS) has been shown to be a safe and effective therapy for patients with chronic pain. However, some patients do not obtain or maintain adequate pain relief after SCS. The goal of this study was to identify factors that affect patient outcome with regard to SCS. MATERIALS AND METHODS: A retrospective analysis of electronic medical records at a single site was performed. Records for 181 patients who received SCS implants from 2014 through 2016 were collected with follow-up data captured up to August 2019. Patient outcome was measured by device explantation and patient benefit from the SCS. Study parameters included demographic characteristics, history of pain, SCS implant characteristics, and postimplantation events. RESULTS: An earlier diagnosis of radiculopathy was associated with an increased risk of poor benefit (relative risk [RR], 1.81; 95% CI, 1.19-2.74; p = 0.008). Postimplantation falls were associated with an increased risk of poor benefit (RR, 2.17; 95% CI, 1.48-3.17; p = 0.009). Device manufacturer was associated with both patient benefit and explantation. Device 2 was associated with a reduced risk of poor benefit (RR, 0.52; 95% CI, 0.32-0.85; p = 0.009). Device 4 was associated with an increased risk of poor benefit (RR, 1.71; 95% CI, 1.14-2.55; p = 0.02) and increased risk of device explantation (RR, 2.69; 95% CI, 1.2-6.02; p = 0.03). CONCLUSIONS: Patient outcome was associated with diagnosis, postimplantation falls, and device manufacturer. Further investigation is recommended to confirm associations through prospective studies that can more accurately quantify patient outcome over longer periods.

Direct targeting of the ventral intermediate nucleus of the thalamus in deep brain stimulation for essential tremor: a prospective study with comparison to a historical cohort.

OBJECTIVE: The ventral intermediate nucleus of the thalamus (VIM) is an effective target for deep brain stimulation (DBS) to control symptoms related to essential tremor. The VIM is typically targeted using indirect methods, although studies have reported visualization of the VIM on proton density-weighted MRI. This study compares the outcomes between patients who underwent VIM DBS with direct and indirect targeting. METHODS: Between August 2013 and December 2019, 230 patients underwent VIM DBS at the senior author's institution. Of these patients, 92 had direct targeting (direct visualization on proton density 3-T MRI). The remaining 138 patients had indirect targeting (relative to the third ventricle and anterior commissure-posterior commissure line). RESULTS: Coordinates of electrodes placed with direct targeting were significantly more lateral (p < 0.001) and anterior (p < 0.001) than those placed with indirect targeting. The optimal stimulation amplitude for devices measured in voltage was lower for those who underwent direct targeting than for those who underwent indirect targeting (p < 0.001). Patients undergoing direct targeting had a greater improvement only in their Quality of Life in Essential Tremor Questionnaire hobby score versus those undergoing indirect targeting (p = 0.04). The direct targeting group had substantially more symptomatic hemorrhages than the indirect targeting group (p = 0.04). All patients who experienced a postoperative hemorrhage after DBS recovered without intervention. CONCLUSIONS: Patients who underwent direct VIM targeting for DBS treatment of essential tremor had similar clinical outcomes to those who underwent indirect targeting. Direct VIM targeting is safe and effective.

Thalamic Deep Brain Stimulation May Improve Restless Legs Syndrome in Patients With Essential Tremor.

OBJECTIVES: To determine change in restless legs syndrome (RLS) symptoms in essential tremor (ET) patients undergoing bilateral thalamic ventral intermedius (VIM) deep brain stimulation (DBS) surgery. MATERIALS AND METHODS: We retrospectively reviewed our database of ET patients with RLS who had undergone VIM DBS for tremor from 2012 to 2020. We reviewed the patients with available International Restless Leg Syndrome Study Group RLS scale scores before and after DBS. Percentage of responders, defined as proportion of patients experiencing three or more point improvement of RLS scores post-DBS, was calculated. We performed two-tailed t-test of pre-DBS and post-DBS RLS scores. RESULTS: We identified 13 patients with ET and RLS who had undergone bilateral VIM DBS, of whom nine (69%) were responders post-DBS. Five of 13 patients (38%) had complete resolution of RLS post-DBS. For all patients, mean pre-DBS RLS score was 15.8 ± 7.9 which improved by 46% post-DBS to a mean of 8.5 ± 8.8 (p = 0.007). Four patients rated their RLS scale one night with the stimulator OFF and another night with the stimulator ON. The mean RLS score with stimulator ON was 15.5 ± 7.6 which improved by 53% to a mean of 6.25 ± 7.8 (p = 0.008), with two having complete resolution of RLS with stimulator ON. Of the nine responders, six preferred to keep their stimulator ON at night due to relief of RLS and better subjective quality of sleep. CONCLUSIONS: We report for the first time improvement of RLS in patients with ET after bilateral thalamic DBS. Although many ET patients with nonrechargeable DBS systems switch off their stimulator at night to conserve battery life, those with RLS may potentially benefit from keeping their stimulator ON at night to relieve their RLS.

Electrophysiologic Mapping for Target Acquisition in Deep Brain Stimulation May Become Unnecessary in the Era of Intraoperative Imaging.

OBJECTIVE: Electrophysiologic mapping (EM) has been instrumental in advancing neuroscience and ensuring accurate lead placement for deep brain stimulation. However, EM is associated with increased operative time, expense, and potential risk. Intraoperative imaging to verify lead placement provides an opportunity to reassess the clinical role of EM. We investigated whether EM 1) provides new information that corrects suboptimal preoperative target selection by the physician or 2) simply corrects intraoperative stereotactic error, which can instead be quickly corrected with intraoperative imaging. METHODS: Deep brain stimulation lead location errors were evaluated by measuring whether repositioning leads based on EM directed the final lead placement 1) away from or 2) toward the original target. We retrospectively identified 50 patients with 61 leads that required repositioning directed by EM. The stereotactic coordinates of each lead were determined with intraoperative computed tomography. RESULTS: In 45 of 61 leads (74%), the electrophysiologically directed repositioning moved the lead toward the initial target. The mean radial errors between the preoperative plan and targeted contact coordinates before and after repositioning were 2.2 and 1.5 mm, respectively (P < 0.001). Microelectrode recording was more likely than test stimulation to direct leads toward the initial target (88% vs. 63%; P = 0.03). The nucleus targeted was associated with the likelihood of moving toward the initial target. CONCLUSIONS: Electrophysiologic mapping corrected primarily for errors in lead placement rather than providing new information regarding errors in target selection. Thus, intraoperative imaging and improvements in stereotactic techniques may reduce or even eliminate dependence on EM.

Tardive Blepharospasm May Respond to Bilateral Pallidal Deep Brain Stimulation.

Background: To date, there have been no reports of tardive blepharospasm being treated with deep brain stimulation (DBS), though there have been two reports of focal blepharospasm responding favorably to bilateral pallidal DBS. Case: A 34 year old man with tardive blepharospasm that was refractory to oral medications as well as botulinum toxin types A and B underwent bilateral pallidal DBS under general anesthesia. He had significant improvement of his severe blepharospasm by one and half months post-DBS which was sustained at last follow-up 30 months post-DBS. The best programming parameters included pulse widths of 90-100 µsec, frequencies of 140-150 Hz, and stimulating the ventral contacts in each side. Conclusion: Our case represents the first report of medically refractory tardive blepharospasm responding favorably to bilateral pallidal DBS.

Perioperative complications of deep brain stimulation among patients with advanced age: a single-institution retrospective analysis.

OBJECTIVE: Deep brain stimulation (DBS) is an elective procedure that can dramatically enhance quality of life. Because DBS is not considered lifesaving, it is important that providers produce consistently good outcomes, and one factor they usually consider is patient age. While older age may be a relative contraindication for some elective surgeries, the progressive nature of movement disorders treated with DBS may suggest that older patients stand to benefit substantially from surgery. To better understand the risks of treating patients of advanced age with DBS, this study compares perioperative complication rates in patients ≥ 75 to those < 75 years old. METHODS: Patients undergoing DBS surgery for various indications by a single surgeon (May 2013-July 2019) were stratified into elderly (age ≥ 75 years) and younger (age < 75 years) cohorts. The risks of common perioperative complications and various outcome measures were compared between the two age groups using risk ratios (RRs) and 95% confidence intervals (CIs). RESULTS: A total of 861 patients were available for analysis: 179 (21%) were ≥ 75 years old and 682 (79%) were < 75 years old (p < 0.001). Patients ≥ 75 years old, compared with those < 75 years old, did not have significantly different RRs (95% CIs) of seizure (RR 0.4, 95% CI 0.1-3.3), cerebrovascular accident (RR 1.9, 95% CI 0.4-10.3), readmission within 90 days of discharge (RR 1.22, 95% CI 0.8-1.8), explantation due to infection (RR 2.5, 95% CI 0.4-15.1), or surgical revision (for lead, RR 2.5, 95% CI 0.4-15.1; for internal pulse generator, RR 3.8, 95% CI 0.2-61.7). Although the risk of postoperative intracranial bleeding was higher in the elderly group (6.1%) than in the younger group (3.1%), this difference was not statistically significant (p = 0.06). However, patients ≥ 75 years old did have significantly increased risk of altered mental status (RR 2.5, 95% CI 1.6-4.0), experiencing more than a 1-night stay (RR 1.7, 95% CI 1.4-2.0), and urinary retention (RR 2.3, 95% CI 1.2-4.2; p = 0.009). CONCLUSIONS: Although elderly patients had higher risks of certain outcome measures than younger patients, this study showed that elderly patients undergoing DBS for movement disorders did not have an increased risk of more serious complications, such as intracranial hemorrhage, infection, or readmission. Advanced age alone should not be considered a contraindication for DBS.

Short-Lasting Unilateral Neuralgiform Headache With Conjunctival Injection and Tearing (SUNCT) Improves With Bilateral Ventral Tegmental Area Deep Brain Stimulation.

BACKGROUND: Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a severe headache disorder characterized by clustered episodes of extreme pain. Refractory to most interventions, ipsilateral unilateral ventral tegmental area (VTA) deep brain stimulation (DBS) has been previously reported to be efficacious in 14 cases. METHODS AND RESULTS: Herein, we report the first case of an individual with medically refractory SUNCT who underwent bilateral VTA DBS. The patient experienced better improvement of his headaches with bilateral stimulation compared to unilateral stimulation. He also had a return of severe headaches within a few hours after his stimulator was switched off during sleep, with rebound worsening of his headaches over several days. The main side effects were double vision and difficulty focusing while reading, which were observed primarily with unipolar stimulation that required high voltages, high frequencies, and multiple negative contacts to control the headaches. The side effects were minimized with bipolar and interleaving stimulation with comparable control of his headaches. CONCLUSION: Bilateral VTA DBS may be effective in alleviating medical refractory SUNCT.

Subcortical Atrophy and Motor Outcomes in Pallidal Deep Brain Stimulation for Parkinson Disease.

BACKGROUND: Appropriate patient selection is critical for successful deep brain stimulation (DBS) for Parkinson disease (PD). Subcortical atrophy is a possible determinant of postoperative DBS outcomes in patients with idiopathic PD, but it has not been well evaluated for DBS of the globus pallidus interna (GPi). We investigated perioperative subcortical atrophy measures in patients with PD and their relationship to postoperative motor response in bilateral GPi-targeted DBS. METHODS: A retrospective cohort study examined correlations among indices of subcortical volumetry, disease duration, and age with postoperative outcomes at 6 months (Unified Parkinson's Disease Rating Scale Part III motor score quotient, levodopa equivalent daily dosing, and 39-item Parkinson's Disease Questionnaire mobility subscore). Subcortical volumetry was assessed by bicaudate ratio, Evans index, and third ventricular width on perioperative imaging. Linear regression models established correlations between preoperative variables and postoperative outcomes. RESULTS: Data from 34 patients with PD who were treated with GPi-targeted DBS were evaluated. Age was found to exhibit statistically significant positive correlations with all 3 measures of subcortical atrophy (P ≤ 0.002). None of the measures correlated with disease duration. Only Evans index and third ventricular width correlated with preoperative medication response (P < 0.05). Age and all 3 measures of atrophy exhibited statistically significant correlations with Unified Parkinson's Disease Rating Scale Part III motor score quotient (P ≤ 0.01), but not with levodopa equivalent daily dosing or 39-item Parkinson's Disease Questionnaire motor subscores (P > 0.05). CONCLUSIONS: Perioperative age and subcortical atrophy as measured in this study correlated with motor responsiveness at 6 months postoperatively among patients receiving bilateral GPi-targeted DBS stimulation for PD.

Effects of implantation of a deep brain stimulation device on patient weight in Parkinson's disease and essential tremor.

OBJECTIVE: Deep brain stimulation (DBS) is a well-established therapy for treating neurological movement disorders. Some patients who have received DBS therapy have noticed significant weight gain. Further investigation into correlations between patient characteristics and weight gain following DBS device implantation, which the authors here have done, will provide physicians with useful clinical information. METHODS: The authors performed a retrospective study of patients with Parkinson's disease (PD) and essential tremor (ET) who had received DBS therapy in the period from 2012 to 2017. Patient weights had been recorded preoperatively and at 3, 6, and 12 months postoperatively. These data were used to compare patient characteristics, including diagnosis, body mass index (BMI), sex, levodopa equivalent dose (LED), and change in Unified Parkinson's Disease Rating Scale (UPDRS) score. For PD patients, a quantile multivariate regression analysis was used to examine whether significant correlations existed between several of these patient characteristics, as well as age and weight gain following implantation. RESULTS: PD patients had gained a significant amount of weight at 3 months (mean [SE] 2.66 [0.428] kg, p < 0.001), 6 months (3.64 [0.492] kg, p < 0.001), and 12 months (4.18 [0.540] kg, p < 0.001) after DBS placement. Patients who had undergone subthalamic nucleus (STN) DBS device placement gained, on average, more weight than the patients with globus pallidus internus (GPi) placement at both 6 months (mean 2.558 [1.020] kg, p = 0.01) and 12 months (2.358 [1.130] kg, p = 0.04). BMI in the STN cohort was greater than that in the GPi cohort at 6 months (mean difference [SE] 2.60 [1.127] kg/m2, p = 0.02) and at 12 months (2.36 [1.112] kg/m2, p = 0.04). A reduction in LED was negatively correlated with weight change at 6 months (r = -0.33, p < 0.001) and 12 months (r = -0.41, p < 0.001). There was no weight gain correlated with DBS therapy for ET. CONCLUSIONS: PD patients experienced a significant change in weight over time after DBS therapy, whereas ET patients did not. PD patients with an STN target site experienced greater weight gain, on average, than those with a GPi target site. Furthermore, there was a significant increase in BMI at 6 and 12 months in patients with an STN target compared to that in patients with a GPi target. PD patients whose LED was reduced after DBS gained more weight at 6 and 12 months after surgery than the patients whose LED was kept at the same level or increased.

Adductor Spasmodic Dysphonia Improves with Bilateral Thalamic Deep Brain Stimulation: Report of 3 Cases Done Asleep and Review of Literature.

Background: To date, there are only six published reports of adductor spasmodic dysphonia (SD) responding to awake thalamic deep brain stimulation (DBS). Methods: We retrospectively reviewed cases of Essential Tremor (ET) with SD that were seen in our center from 2012 to 2020. We further identified those that have undergone thalamic DBS, and had a blinded laryngologist rate first the audio voice recordings before and after DBS using the Unified Spasmodic Dysphonia Rating Scale (USDRS), and the video recordings last to rate the related movements and facial grimacing. Results: We identified three cases of adductor SD with ET that had undergone bilateral ventralis intermedius (VIM) DBS under general anesthesia. All patients noted improvement of their limb and voice tremor, as well as their SD post-DBS. Although improvement of tremor was observed even with initial programming in all three, improvement of SD was noted only upon reaching higher amplitudes or wider pulse widths. Blinded voice assessments showed improvement of USDRS scores post-DBS compared to pre-DBS, and with stimulator on compared to stimulator off. Discussion: We report the first three cases of SD responding favorably to bilateral VIM asleep DBS and summarize the nine cases so far of SD who have undergone thalamic DBS.

Procedural Variables Influencing Stereotactic Accuracy and Efficiency in Deep Brain Stimulation Surgery.

BACKGROUND: Deep brain stimulation (DBS) is well-established, evidence-based therapy for Parkinson disease, essential tremor, and primary dystonia. Clinical outcome studies have recently shown that "asleep" DBS lead placement, performed using intraoperative imaging with stereotactic accuracy as the surgical endpoint, has motor outcomes comparable to traditional "awake" DBS using microelectrode recording (MER), but with shorter case times and improved speech fluency. OBJECTIVE: To identify procedural variables in DBS surgery associated with improved surgical efficiency and stereotactic accuracy. METHODS: Retrospective review of 323 cases with 546 leads placed (August 2011-October 2014). In 52% (n = 168) of cases, patients were asleep under general anesthesia without MER. Multivariate regression identified independent predictors of reduced surgery time and improved stereotactic accuracy. RESULTS: MER was an independent contributor to increased procedure time (+44 min; P = .03). Stereotactic accuracy was better in asleep patients. Accuracy was improved with frame-based stereotaxy at head of bed 0° vs frameless stereotaxy at head of bed 30°. Improved accuracy was also associated with shorter procedures (r = 0.17; P = .049). Vector errors were evenly distributed around the planned target for the globus pallidus internus, but directionally skewed for the subthalamic (medial-posterior) and ventral intermediate nuclei (medial-anterior). CONCLUSION: Distinct procedural variables in DBS surgery are associated with reduced case times and improved stereotactic accuracy.

Peri-Lead Edema After Deep Brain Stimulation Surgery: A Poorly Understood but Frequent Complication.

OBJECTIVE: Postoperative peri-lead edema (PLE) is a poorly understood complication of deep brain stimulation (DBS), which has been described sporadically in patients presenting with profound and often delayed symptoms. We performed a prospective evaluation of patients undergoing DBS to determine the frequency of and identify risk factors for PLE. METHODS: Patients underwent DBS electrode placement by a single physician. Postoperative magnetic resonance imaging (MRI) was performed approximately 6 weeks after the operation in asymptomatic subjects and analyzed for presence of PLE. All symptomatic subjects underwent MRI at the time of presentation. Data regarding index disease, preoperative medical issues, operative technique, and intraoperative variables were collected and statistically analyzed. RESULTS: A total of 191 leads were placed in 102 subjects; 15 patients (14.7%) demonstrated PLE. Seven patients (6.9%) presented with symptoms related to PLE, most often altered mental status or neurologic deficit. Many of the MRI findings were profound, with PLE sometimes several centimeters in diameter. No statistically significant difference was found between PLE-positive and normal subjects when analyzing multiple variables, including presence of vascular disease, hypertension, anticoagulant/antiplatelet use, electrode target, index disease, unilateral versus bilateral lead placement, number of brain penetrations, and presence or absence of microelectrode recording. CONCLUSIONS: Patients with postoperative PLE can present with severe symptoms or can be asymptomatic and go undiagnosed. Because of the delayed-onset potential, PLE may be more common than previously reported. No clear risk factors have been identified; therefore, further studies and increased clinical vigilance are paramount for improving comprehension and possible prevention of PLE.

Orthostatic Tremor is Responsive to Bilateral Thalamic Deep Brain Stimulation: Report of Two Cases Performed Asleep.

Background: Orthostatic tremor (OT) is a hyperkinetic movement disorder characterized by rapid tremor in the lower extremities or trunk upon standing. Case Report: We report two patients presenting with OT, whose symptoms improved markedly following asleep bilateral thalamic deep brain stimulation (DBS) surgery. Discussion: Medically refractory OT can respond favorably to asleep bilateral DBS surgery similar to awake surgery, and may have the advantages of less psychological trauma to the patient, shorter procedure times, and less exposure to anesthesia.

Clinical outcomes following awake and asleep deep brain stimulation for Parkinson disease.

OBJECTIVE: Recent studies have shown similar clinical outcomes between Parkinson disease (PD) patients treated with deep brain stimulation (DBS) under general anesthesia without microelectrode recording (MER), so-called "asleep" DBS, and historical cohorts undergoing "awake" DBS with MER guidance. However, few studies include internal controls. This study aims to compare clinical outcomes after globus pallidus internus (GPi) and subthalamic nucleus (STN) DBS using awake and asleep techniques at a single institution. METHODS: PD patients undergoing awake or asleep bilateral GPi or STN DBS were prospectively monitored. The primary outcome measure was stimulation-induced change in motor function off medication 6 months postoperatively, measured using the Unified Parkinson's Disease Rating Scale part III (UPDRS-III). Secondary outcomes included change in quality of life, measured by the 39-item Parkinson's Disease Questionnaire (PDQ-39), change in levodopa equivalent daily dosage (LEDD), stereotactic accuracy, stimulation parameters, and adverse events. RESULTS: Six-month outcome data were available for 133 patients treated over 45 months (78 GPi [16 awake, 62 asleep] and 55 STN [14 awake, 41 asleep]). UPDRS-III score improvement with stimulation did not differ between awake and asleep groups for GPi (awake, 20.8 points [38.5%]; asleep, 18.8 points [37.5%]; p = 0.45) or STN (awake, 21.6 points [40.3%]; asleep, 26.1 points [48.8%]; p = 0.20) targets. The percentage improvement in PDQ-39 and LEDD was similar for awake and asleep groups for both GPi (p = 0.80 and p = 0.54, respectively) and STN cohorts (p = 0.85 and p = 0.49, respectively). CONCLUSIONS: In PD patients, bilateral GPi and STN DBS using the asleep method resulted in motor, quality-of-life, and medication reduction outcomes that were comparable to those of the awake method.

Intraoperative test stimulation versus stereotactic accuracy as a surgical end point: a comparison of essential tremor outcomes after ventral intermediate nucleus deep brain stimulation.

OBJECTIVE Ventral intermediate nucleus deep brain stimulation (DBS) for essential tremor is traditionally performed with intraoperative test stimulation and conscious sedation, without general anesthesia (GA). Recently, the authors reported retrospective data on 17 patients undergoing DBS after induction of GA with standardized anatomical coordinates on T1-weighted MRI sequences used for indirect targeting. Here, they compare prospectively collected data from essential tremor patients undergoing DBS both with GA and without GA (non-GA). METHODS Clinical outcomes were prospectively collected at baseline and 3-month follow-up for patients undergoing DBS surgery performed by a single surgeon. Stereotactic, euclidean, and radial errors of lead placement were calculated. Functional (activities of daily living), quality of life (Quality of Life in Essential Tremor [QUEST] questionnaire), and tremor severity outcomes were compared between groups. RESULTS Fifty-six patients underwent surgery: 16 without GA (24 electrodes) and 40 with GA (66 electrodes). The mean baseline functional scores and QUEST summary indices were not different between groups (p = 0.91 and p = 0.59, respectively). Non-GA and GA groups did not differ significantly regarding mean postoperative percentages of functional improvement (non-GA, 47.9% vs GA, 48.1%; p = 0.96) or QUEST summary indices (non-GA, 79.9% vs GA, 74.8%; p = 0.50). Accuracy was comparable between groups (mean radial error 0.9 ± 0.3 mm for non-GA and 0.9 ± 0.4 mm for GA patients) (p = 0.75). The mean euclidean error was also similar between groups (non-GA, 1.1 ± 0.6 mm vs GA, 1.2 ± 0.5 mm; p = 0.92). No patient had an intraoperative complication, and the number of postoperative complications was not different between groups (non-GA, n = 1 vs GA, n = 10; p = 0.16). CONCLUSIONS DBS performed with the patient under GA to treat essential tremor is as safe and effective as traditional DBS surgery with intraoperative test stimulation while the patient is under conscious sedation without GA.

Cost of Deep Brain Stimulation Infection Resulting in Explantation.

BACKGROUND: Deep brain stimulation (DBS) hardware infection is a serious complication, often resulting in multiple hardware salvage attempts, hospitalizations, and long-term antibiotic therapy. OBJECTIVES: We aimed to quantify the costs of DBS hardware-related infections in patients undergoing eventual device explantation. METHODS: Of 362 patients who underwent 530 electrode placements (1 January 2010 to 30 December 2014), 16 (4.4%) had at least 2 hardware salvage procedures. Most (n = 15 [93.8%]) required complete explantation due to recurrent infection. Financial data (itemized hospital and physician costs) were available for 13 patients and these were analyzed along with the demographic data. RESULTS: Each patient underwent 1-5 salvage procedures (mean 2.5 ± 1.4; median 2). The mean total cost for a patient undergoing the median number of revisions (n = 2), device explantation, and subsequent reimplantation after infection clearance was USD 75,505; just over half this cost (54.2% [USD 40,960]) was attributable to reimplantation, and nearly one-third (28.9% [USD 21,816]) was attributable to hardware salvage procedures. Operating-room costs were the highest cost category for hardware revision and explantation. Medical and surgical supplies accounted for the highest reimplantation cost. CONCLUSIONS: DBS infection incurs significant health care costs associated with hardware salvage attempts, explantation, and reimplantation. The highest cost categories are operating-room services and medical and surgical supplies.

Complication rates, lengths of stay, and readmission rates in "awake" and "asleep" deep brain simulation.

OBJECTIVE As the number of deep brain stimulation (DBS) procedures performed under general anesthesia ("asleep" DBS) increases, it is more important to assess the rates of adverse events, inpatient lengths of stay (LOS), and 30-day readmission rates in patients undergoing these procedures compared with those in patients undergoing traditional "awake" DBS without general anesthesia. METHODS All patients in an institutional database who had undergone awake or asleep DBS procedures performed by a single surgeon between August 2011 and August 2014 were reviewed. Adverse events, inpatient LOS, and 30-day readmissions were analyzed. RESULTS A total of 490 electrodes were placed in 284 patients, of whom 126 (44.4%) underwent awake surgery and 158 (55.6%) underwent asleep surgery. The most frequent overall complication for the cohort was postoperative mental status change (13 patients [4.6%]), followed by hemorrhage (4 patients [1.4%]), seizure (4 patients [1.4%]), and hardware-related infection (3 patients [1.1%]). Mean LOS for all 284 patients was 1.19 ± 1.29 days (awake: 1.06 ± 0.46 days; asleep: 1.30 ± 1.67 days; p = 0.08). Overall, the 30-day readmission rate was 1.4% (1 awake patient, 3 asleep patients). There were no significant differences in complications, LOS, and 30-day readmissions between awake and asleep groups. CONCLUSIONS Both awake and asleep DBS can be performed safely with low complication rates. The authors found no significant differences between the 2 procedure groups in adverse events, inpatient LOS, and 30-day readmission rates.

"Asleep" deep brain stimulation for essential tremor.

OBJECT Deep brain stimulation (DBS) performed under general anesthesia ("asleep" DBS) has not been previously reported for essential tremor. This is in part due to the inability to visualize the target (the ventral intermediate nucleus [VIM]) on MRI. The authors evaluate the efficacy of this asleep technique in treating essential tremor by indirect VIM targeting. METHODS The authors retrospectively reviewed consecutive cases of initial DBS for essential tremor performed by a single surgeon. DBS was performed with patients awake (n = 40, intraoperative test stimulation without microelectrode recording) or asleep (n = 17, under general anesthesia). Targeting proceeded with standardized anatomical coordinates on preoperative MRI. Intraoperative CT was used for stereotactic registration and lead position confirmation. Functional outcomes were evaluated with pre- and postoperative Bain and Findley Tremor Activities of Daily Living scores. RESULTS A total of 29 leads were placed in asleep patients, and 60 were placed in awake patients. Bain and Findley Tremor Activities of Daily Living Questionnaire scores were not significantly different preoperatively for awake versus asleep cohorts (p = 0.2). The percentage of postoperative improvement was not significantly different between asleep (48.6%) and awake (45.5%) cohorts (p = 0.35). Euclidean error (mm) was higher for awake versus asleep patients (1.7 ± 0.8 vs 1.2 ± 0.4, p = 0.01), and radial error (mm) trended higherfor awake versus asleep patients (1.3 ± 0.8 vs 0.9 ± 0.5, p = 0.06). There were no perioperative complications. CONCLUSIONS In the authors' initial experience, asleep VIM DBS for essential tremor without intraoperative test stimulation can be performed safely and effectively.

Dentures are a Reservoir for Respiratory Pathogens.

PURPOSE: Recent studies have established a relationship between dental plaque and pulmonary infection, particularly in elderly individuals. Given that approximately one in five adults in the UK currently wears a denture, there remains a gap in our understanding of the direct implications of denture plaque on systemic health. The aim of this study was to undertake a comprehensive evaluation of putative respiratory pathogens residing upon dentures using a targeted quantitative molecular approach. MATERIALS AND METHODS: One hundred and thirty patients' dentures were sonicated to remove denture plaque biofilm from the surface. DNA was extracted from the samples and was assessed for the presence of respiratory pathogens by quantitative polymerase chain reaction (qPCR). Ct values were then used to approximate the number of corresponding colony forming equivalents (CFEs) based on standard curves. RESULTS: Of the dentures, 64.6% were colonized by known respiratory pathogens. Six species were identified: Streptococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Haemophilus influenzae B, Streptococcus pyogenes, and Moraxella catarrhalis. P. aeruginosa was the most abundant species followed by S. pneumoniae and S. aureus in terms of average CFE and overall proportion of denture plaque. Of the participants, 37% suffered from denture stomatitis; however, there were no significant differences in the prevalence of respiratory pathogens on dentures between healthy and inflamed mouths. CONCLUSIONS: Our findings indicate that dentures can act as a reservoir for potential respiratory pathogens in the oral cavity, thus increasing the theoretical risk of developing aspiration pneumonia. Implementation of routine denture hygiene practices could help to reduce the risk of respiratory infection among the elderly population.