Characteristics of shunt failure in 38,095 adult shunt insertion surgeries: a systematic review and meta-analysis.

OBJECTIVE: The management of excess CSF in patients with hydrocephalus typically requires using a shunt to divert CSF. Unfortunately, there is a high rate of shunt failure despite improvements in device components and insertion techniques. Reoperation is frequently necessary, which contributes to patient harm and increased healthcare costs. While factors affecting shunt failure are well defined in the pediatric population, information regarding adults is lacking. The authors undertook a systematic review and meta-analysis to determine how shunt failure in the adult population is reported and investigated the etiologies of shunt failure. METHODS: This review is reported according to PRIMSA and utilized the MEDLINE, Embase, and Google Scholar databases. Abstracts were screened by two independent reviewers, and data were extracted in duplicate by two independent reviewers. Statistical analyses were performed using SPSS and Stata. RESULTS: The pooled rates of shunt failure were 10% (95% CI 5%-15%) in studies with a mean follow-up time of less than 1 year, 12% (95% CI 8%-14%) with a follow-up time between 1 and 2 years, and 32% in studies with a follow-up time of 2 years or greater (95% CI 19%-43%). The pooled rate of failure was 17% across all studies. The most common cause of shunt failure was obstruction at 3.0% (95% CI 2%-4%), accounting for 23.2% of shunt failures. Infection was the second most common at 2.8% (95% CI 2%-3%), accounting for 22.5% of shunt failures. The most common location of shunt failure was the distal catheter, with a failure rate of 4.0% (95% CI 3%-5%), accounting for 33.4% of shunt failures. The definition of shunt failure was heterogeneous and varied depending on institutional practices. The combination of symptoms with either CT or MRI was the most frequently reported method for assessing shunt failure. CONCLUSIONS: Important variation regarding how to define, investigate, and report shunt failure was identified. The overall shunt failure rate in adults is at least 32% after 2 years, which, while lower than that typically reported in the pediatric population, is significant. The most common causes of shunt failure in adults are infection and obstruction. The most common site of failure occurred at the distal catheter, highlighting the need to develop strategies to both report and mitigate distal shunt failure in adult shunt patients.

Prognosis-Guided Reconstruction of Scalp and Skull Defects in Neurosurgical Patients.

BACKGROUND: This study aimed to formulate reconstructive recommendations for neurosurgical patients presenting with scalp and/or skull defects based on outcomes in a large series of patients. METHODS: An institutional review board-approved retrospective review of patients who underwent scalp and/or calvarial reconstruction was conducted. Complications were divided into minor and major; early, intermediate, and late. Univariate logistic regression models were conducted to identify independent predictors of complications. Mann-Whitney U tests were used to compare survival time. Kaplan-Meier curves were developed to compare exposure of titanium and bone cranioplasties. RESULTS: One hundred seventy-one patients who underwent 418 procedures were included (median 1 [1-3] surgeries per patient). Average age was 55 ± 15 years; 53% of patients were male. Median follow-up was 25.5 months [13.9-55.6 months], and 57 patients (33%) were deceased. Complications occurred following 48% of procedures; most common were titanium hardware exposure (36%), nonhealing wounds (23%), and infection (9%). Titanium cranioplasties became exposed 0.47 months [0.3-4.0 months] postoperatively. Frontal defect location was an independent predictor of major complications (odds ratio, 1.59; 95% confidence interval, 1.06-2.39; P = 0.026). Mortality rate for malignant intracranial neoplasms was 68.4% (median survival, 4.3 months), 39.1% for malignancies of both scalp and skull (7.0 months), 37.5% for scalp cancers (16.0 months), and 16.7% for meningiomas (28.2 months). CONCLUSIONS: Neurosurgical patients requiring scalp and/or skull reconstruction are a complex population undergoing multiple procedures with high complication rates. Given high exposure rate of titanium hardware shortly after reconstruction, titanium cranioplasty is recommended for patients with a prognosis less than 2 to 8 months.

Directional Stimulation in Parkinson's Disease and Essential Tremor: The Cleveland Clinic Experience.

OBJECTIVE: To assess use of directional stimulation in Parkinson's disease and essential tremor patients programmed in routine clinical care. MATERIALS AND METHODS: Patients with Parkinson's disease or essential tremor implanted at Cleveland Clinic with a directional deep brain stimulation (DBS) system from November 2017 to October 2019 were included in this retrospective case series. Omnidirectional was compared against directional stimulation using therapeutic current strength, therapeutic window percentage, and total electrical energy delivered as outcome variables. RESULTS: Fifty-seven Parkinson's disease patients (36 males) were implanted in the subthalamic nucleus (105 leads) and 33 essential tremor patients (19 males) were implanted in the ventral intermediate nucleus of the thalamus (52 leads). Seventy-four percent of patients with subthalamic stimulation (65% of leads) and 79% of patients with thalamic stimulation (79% of leads) were programmed with directional stimulation for their stable settings. Forty-six percent of subthalamic leads and 69% of thalamic leads were programmed on single segment activation. There was no correlation between the length of microelectrode trajectory through the STN and use of directional stimulation. CONCLUSIONS: Directional programming was more common than omnidirectional programming. Substantial gains in therapeutic current strength, therapeutic window, and total electrical energy were found in subthalamic and thalamic leads programmed on directional stimulation.

Directional Deep Brain Stimulation for Parkinson's Disease: Results of an International Crossover Study With Randomized, Double-Blind Primary Endpoint.

OBJECTIVE: Published reports on directional deep brain stimulation (DBS) have been limited to small, single-center investigations. Therapeutic window (TW) is used to describe the range of stimulation amplitudes achieving symptom relief without side effects. This crossover study performed a randomized double-blind assessment of TW for directional and omnidirectional DBS in a large cohort of patients implanted with a DBS system in the subthalamic nucleus for Parkinson's disease. MATERIALS AND METHODS: Participants received omnidirectional stimulation for the first three months after initial study programming, followed by directional DBS for the following three months. The primary endpoint was a double-blind, randomized evaluation of TW for directional vs omnidirectional stimulation at three months after initial study programming. Additional data recorded at three- and six-month follow-ups included stimulation preference, therapeutic current strength, Unified Parkinson's Disease Rating Scale (UPDRS) part III motor score, and quality of life. RESULTS: The study enrolled 234 subjects (62 ± 8 years, 33% female). TW was wider using directional stimulation in 183 of 202 subjects (90.6%). The mean increase in TW with directional stimulation was 41% (2.98 ± 1.38 mA, compared to 2.11 ± 1.33 mA for omnidirectional). UPDRS part III motor score on medication improved 42.4% at three months (after three months of omnidirectional stimulation) and 43.3% at six months (after three months of directional stimulation) with stimulation on, compared to stimulation off. After six months, 52.8% of subjects blinded to stimulation type (102/193) preferred the period with directional stimulation, and 25.9% (50/193) preferred the omnidirectional period. The directional period was preferred by 58.5% of clinicians (113/193) vs 21.2% (41/193) who preferred the omnidirectional period. CONCLUSION: Directional stimulation yielded a wider TW compared to omnidirectional stimulation and was preferred by blinded subjects and clinicians.

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.

Extended lumbar drainage in idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis of diagnostic test accuracy.

BACKGROUND: When appropriately selected, a high proportion of patients with suspected idiopathic normal pressure hydrocephalus (iNPH) will respond to cerebrospinal fluid diversion with a shunt. Extended lumbar drainage (ELD) is regarded as the most accurate test for this condition, however, varying estimates of its accuracy are found in the current literature. Here, we review the literature in order to provide summary estimates of sensitivity, specificity, positive- and negative predictive value for this test through meta-analysis of suitably rigorous studies. METHODS: Studies involving a population of NPH patients with predominantly idiopathic aetiology (>80%) in which the intention of the study was to shunt patients regardless of the outcome of ELD were included in the review. Various literature databases were searched to identify diagnostic test accuracy studies addressing ELD in the diagnosis of iNPH. Those studies passing screening and eligibility were assessed using the QUADAS-2 tool and data extracted for bivariate random effects meta-analysis. RESULTS: Four small studies were identified. They showed disparate results concerning diagnostic test accuracy. The summary estimates for sensitivity and specificity were 94% (CI 41-100%) and 85% (CI 33-100%), respectively. The summary estimates of positive and negative predictive value were both 90% (CIs 65-100% and 48-100%, respectively). CONCLUSION: Large, rigorous studies addressing the diagnostic accuracy of ELD are lacking, and little robust evidence exists to support the use of ELD in diagnostic algorithms for iNPH. Therefore, a large cohort study, or ideally an RCT, is needed to determine best practice in selecting patients for shunt surgery.

The Need for Digital Health Solutions in Deep Brain Stimulation for Parkinson's Disease in the Time of COVID-19 and Beyond.

OBJECTIVES: Deep brain stimulation (DBS) is a well-established therapy for the management of patients with advanced Parkinson's disease and other movement disorders. Patients implanted with DBS require life-long management of the medical device as well as medications. Patients are often challenged to frequently visit the specialized DBS centers and such challenges are aggravated depending on geography, socioeconomic factors, and support systems. We discuss the need for digital health solutions to overcome these barriers to better and safely take care of patients, especially in the current COVID-19 pandemic. MATERIALS AND METHODS: A review of the literature was conducted for technology and logistics necessary in forming a digital health program. RESULTS: Digital health encounters can take place in both a synchronous and asynchronous manner. Factors involving patients include cognitive capacity, physical safety, physical capacity, connectivity, and technological security. Physician factors include examining the patient, system diagnostics, and adjusting stimulation or medications. Technology is focused on bridging the gap between patient and physician through integrating the DBS lead, implantable pulse generator (IPG), programmer, novel devices/applications to grade motor function, and teleconference modalities. CONCLUSIONS: For patients with Parkinson's disease, digital health has the potential to drastically change the landscape after DBS surgery. Furthermore, technology is fundamental in connectivity, diagnostic evaluation, and security in order to create stable and useful patient-focused care.

Biomarker Optimization of Spinal Cord Stimulation Therapies.

OBJECTIVES: We are in the process of designing and testing an intradural stimulation device that will shorten the distance between the location of the electrode array and the targeted neural tissue, thus improving the efficacy of electrical current delivery. Identifying a biomarker that accurately reflects the response to this intervention is highly valued because of the potential to optimize interventional parameters or predict a response before it is clinically measurable. In this report, we summarize the findings pertaining to the study of biomarkers so that we and others will have an up-to-date reference that critically evaluates the current approaches and select one or several for testing during the development of our device. MATERIALS AND METHODS: We have conducted a broad survey of the existing literature to catalogue the biomarkers that could be coupled to intradural spinal cord stimulation. We describe in detail some of the most promising biomarkers, existing limitations, and suitability to managing chronic pain. RESULTS: Chronic, intractable pain is an all-encompassing condition that is incurable. Many treatments for managing chronic pain are nonspecific in action and intermittently administered; therefore, patients are particularly susceptible to large fluctuations in pain control over the course of a day. The absence of a reliable biomarker challenges assessment of therapeutic efficacy and contributes to either incomplete and inconsistent pain relief or, alternatively, intolerable side effects. Fluctuations in metabolites or inflammatory markers, signals captured during dynamic imaging, and genomics will likely have a role in governing how a device is modulated. CONCLUSIONS: Efforts to identify one or more biomarkers are well underway with some preliminary evidence supporting their efficacy. This has far-reaching implications, including improved outcomes, fewer adverse events, harmonization of treatment and individuals, performance gains, and cost savings. We anticipate that novel biomarkers will be used widely to manage chronic pain.

Long-term Outcomes Using Intrathecal Drug Delivery Systems in Complex Regional Pain Syndrome.

OBJECTIVE: Providing durable long-term pain control for patients with complex regional pain syndrome (CRPS) is challenging. A multidisciplinary approach focused on physical therapy is frequently prescribed, with opioids and invasive procedures reserved for those challenged by functional progression. In this study, we examined the long-term efficacy of intrathecal drug delivery systems (IDDS) in patients with CRPS at our institution. METHODS: Patients with CRPS implanted with an IDDS between 2000 and 2013 who had four or more years of continuous follow-up were included in the analysis. The outcome variables of interest were pain intensity and oral opioid intake. The primary predictor of interest was dose of intrathecal opioids, with ziconotide, bupivacaine, and clonidine characterized as binary secondary predictors. RESULTS: Of the 1,653 IDDS identified, 62 were implanted primarily for CRPS-related pain. Of these, 26 had four or more years of complete follow-up data. Pain scores did not significantly decrease over time, and we observed no correlation between pain intensity and use of any intrathecal medication. Although oral opioid intake decreased over time, intrathecal opioid dose did not affect oral opioid consumption. Ziconotide was associated with a hastening of the decrease in oral opioid intake, whereas the presence of bupivacaine paradoxically increased oral opioid intake. CONCLUSIONS: Our study demonstrates that intrathecal opioid dose was not associated with long-term decreases in oral opioid intake. Additionally, ziconotide was associated with a decrease in oral opioid intake over the four-year follow-up, and bupivacaine was associated with an increase in oral opioid intake. Our study examines the long-term effectiveness of intrathecal medications in managing pain in patients with complex regional pain syndrome. We present a detailed follow-up over four years for 26 patients, tracking oral opiate intake, pain scores, and intrathecal pump settings. Our findings suggest that intrathecal opiates may not be effective in reducing oral opiate intake, ziconotide may hasten a decrease in intake, and bupivacaine may lead to an increase in intake.

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.

Long-term Outcomes of Cranioplasty: Titanium Mesh Is Not a Long-term Solution in High-risk Patients.

BACKGROUND: Titanium mesh is a popular material for cranioplasty. However, long-term outcomes of these reconstructions remain unknown. We aimed to compare long-term outcomes between patients undergoing both (1) skull reconstruction with titanium mesh and other commonly used cranioplasty materials and (2) scalp reconstructions with locoregional flaps and free tissue transfers. METHODS: A retrospective review of patients treated with 466 cranioplasties (401 patients) between 2002 and 2014 was performed. RESULTS: Materials used for reconstructions included nontitanium alloplast (52.0%), titanium mesh (38%), and autologous bone (10%). Median cranial defect size was 58.4 cm. Eighty-three reconstructions (18%) included full-thickness scalp defect with a median area of 155.4 cm. Median follow-up was 3.9 years. Retention rate for isolated cranioplasty was 90%, 89.9%, and 77.1% for titanium mesh, nontitanium alloplast, and autologous bone, respectively (P > 0.05). In composite defect cases, retention rate for autologous bone was comparable, 81.8% (P > 0.05), whereas for titanium mesh and nontitanium alloplast it was significantly lower, 46.8% and 72.0%, respectively (P < 0.05). The retention rate of titanium mesh cranioplasty with free fascio- and myocutaneous flaps was higher when compared with locoregional and free muscle flaps (P < 0.05). CONCLUSIONS: Titanium mesh offers a durable repair of isolated bone defects. However, in high-risk patients with soft-tissue defect, the outcomes are significantly worse. In these cases, free tissue transfer for soft-tissue coverage tends to be more successful, especially when using a myocutaneous or fasciocutaneous free flap. This is the first study to identify a high complication rate of this popular material, especially when it is combined with a locoregional scalp flap or free muscle flap. Therefore, in these cases, titanium mesh should be used with caution.

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.

Case Series: Intrathecal Baclofen Therapy in Stiff-Person Syndrome.

OBJECTIVES: Stiff-person syndrome (SPS) is associated with axial rigidity superimposed on sustained muscle spasms. These symptoms commonly interfere with the performance of activities of daily living including ambulation. This retrospective case series evaluates the outcomes of screening tests and chronic infusion of intrathecal baclofen (ITB) in patients diagnosed with SPS treated in our spasticity clinic. MATERIALS AND METHODS: Patients were identified from an institutional review board-approved clinical registry of ITB therapy. Data from clinical encounters were extracted from the registry and from the patients' electronic medical record. All patients with medically refractory spasticity related to SPS screened with an ITB injection were included. In addition to pertinent demographic and clinical information, data from validated outcome measures routinely used in the clinic were collected: pain Numeric Rating Scale, Spasm Frequency Scale, lower extremity Modified Ashworth Scale (MAS), and Timed 25 Foot Walk. Outcomes data for chronic ITB infusion were assessed at early (<6 months) and late follow-up (6-12 months) visits after surgery. RESULTS: Nine patients were included, and seven received chronic ITB infusion. MAS scores were improved at early and late follow-up, and five patients experienced a reduction in pain scores. Walking performance remained stable in previously ambulatory patients. Four patients experienced complications related to ITB implantation, which resolved with medical or surgical treatment. CONCLUSION: Consistent with other case series, our results suggest that ITB is an effective therapy for medically intractable spasticity due to SPS, and symptom reduction can be achieved without compromising ambulation.

Intrathecal Therapeutics: Device Design, Access Methods, and Complication Mitigation.

INTRODUCTION: The intrathecal space remains underutilized for diagnostic testing, invasive monitoring or as a pipeline for the delivery of neurological therapeutic agents and devices. The latter including drug infusions, implants for electrical modulation, and a means for maintaining the physiologic pressure column. The reasons for this are many but include unfamiliarity with the central nervous system and the historical risks that continue to overshadow the low complication rates in modern clinical series. MATERIALS AND METHODS: Our intent in this review is to explore the access devices currently on the market, assess the risk associated with breaching the intrathecal space, and propose a research model for bringing to patients the next generation of intrathecal hardware. For this purpose, we reviewed both historical and contemporary literature that pertains to the access devices and catheters intended for both temporary and permanent implantation and the complications thereof. RESULTS: There are few devices that are currently marketed in the United States or Europe for intrathecal use. Most hew to a relatively fixed design pattern predicated on the dimensions and properties of the thecal sac. All are typically composed of soft silicone, and employ a Tuohy needle for access despite design limitations. In general, these catheters are engineered for durability, ease of use, and regional deployment. Devices on the market with steerability or targeted intrathecal fixation are not yet available. Complications, once a legitimate concern, are now quite rare when recommended techniques are followed. CONCLUSIONS: Over the next decade, advances in intrathecal catheter design, access techniques, imaging, and greater understanding of the spinal cord neurophysiology will usher in an era where the intrathecal space is recognized as a highly valued diagnostic and therapeutic target. We anticipate that this will occur in several concurrent phases, each with the potential to accelerate the growth of the others.

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.

Spinal Cord Stimulation for Spasticity: Historical Approaches, Current Status, and Future Directions.

INTRODUCTION: Millions of people worldwide suffer with spasticity related to irreversible damage to the brain or spinal cord. Typical antecedent events include stroke, traumatic brain injury, and spinal cord injury, although insidious onset is also common. Regardless of the cause, the resulting spasticity leads to years of disability and reduced quality of life. Many treatments are available to manage spasticity; yet each is fraught with drawbacks including incomplete response, high cost, limited duration, dose-limiting side effects, and periodic maintenance. Spinal cord stimulation (SCS), a once promising therapy for spasticity, has largely been relegated to permanent experimental status. METHODS: In this review, our goal is to document and critique the history and assess the development of SCS as a treatment of lower limb spasticity. By incorporating recent discoveries with the insights gained from the early pioneers in this field, we intend to lay the groundwork needed to propose testable hypotheses for future studies. RESULTS: SCS has been tested in over 25 different conditions since a potentially beneficial effect was first reported in 1973. However, the lack of a fully formed understanding of the pathophysiology of spasticity, archaic study methodology, and the early technological limitations of implantable hardware limit the validity of many studies. SCS offers a measure of control for spasticity that cannot be duplicated with other interventions. CONCLUSIONS: With improved energy-source miniaturization, tailored control algorithms, novel implant design, and a clearer picture of the pathophysiology of spasticity, we are poised to reintroduce and test SCS in this population.

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.

Outcomes of Calvarial and Soft-Tissue Reconstruction with Latissimus Dorsi-Rib Osteomyocutaneous Free Flap.

BACKGROUND: The latissimus dorsi-rib osteomyocutaneous free flap (LDRF) has been used for autologous reconstruction of large composite calvarial and scalp defects. In this study, the authors aim to present clinical and patient-reported outcomes after LDRF reconstruction. METHODS: An anatomical study was conducted to evaluate the distribution of the connecting perforators between the thoracodorsal and intercostal systems. An institutional review board-approved retrospective review of 10 patients who underwent LDRF with one or two ribs for treatment of cranial defects was conducted. Patient-reported outcomes regarding quality of life, neurologic status, and functional status were evaluated using validated surveys. One-way analysis of variance and post hoc Tukey tests were used for anatomical outcomes. Preoperative and postoperative scores were compared using paired t tests. RESULTS: The tenth rib (4.65 ± 2.01) followed by the ninth rib (3.7 ± 1.63) had the highest number of perforators. A combination of the ninth and eleventh ribs exhibited maximal perforator number and pedicle length. All patients had stable LDRF reconstructions. Eight patients completed both preoperative and postoperative questionnaires; Median clinical follow-up was 48 months (range, 34 to 70 months). Scores trended toward improvement but did not reach statistical significance on the Karnofsky Performance Scale ( P = 0.22), the Functional Independence Measure (Motor, P = 0.52; Cognitive, P = 0.55), or the Headache Disability Index ( P = 0.38). The minimum clinically important difference was surpassed, demonstrating improvement of function for 71% of patients on the Barthel Index and 63% on the Selective Functional Movement Assessment test. CONCLUSION: The LDRF can improve cognitive and physical functional status in complex patients with prior failed reconstructions for composite scalp and skull defects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Feasibility of Magnetic Resonance-Compatible Accelerometers to Monitor Tremor Fluctuations During Magnetic Resonance-Guided Focused Ultrasound Thalamotomy: Technical Note.

BACKGROUND: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is used to treat essential tremor and tremor-dominant Parkinson disease. Feedback is collected throughout the procedure to verify the location of the target and completeness of response; however, variability in clinical judgments may underestimate or overestimate treatment response. OBJECTIVE: To objectively quantify joint motion after each sonication using accelerometers secured to the contralateral upper extremity in an effort to optimize MRgFUS treatment. METHODS: Before the procedure, 3 accelerometers were secured to the patient's arm, forearm, and index finger. Throughout the procedure, tremor motion was regularly recorded during postural and kinetic tremor testing and individual joint angle measures were modeled. The joint angle from each accelerometer was compared with baseline measurements to assess changes in angles. Subsequent adjustments to the target location and sonication energy were made at the discretion of the neurosurgeon and neuroradiologist. RESULTS: Intraoperative accelerometer measurements of hand tremor from 18 patients provided quantified data regarding joint angle reduction: 87.3%, 94.2%, and 86.7% for signature writing, spiral drawing, and line drawing tests, respectively. Target adjustment based on accelerometer monitoring of the angle at each joint added substantial value toward achieving optimal tremor reduction. CONCLUSION: Real-time accelerometer recordings collected during MRgFUS thalamotomy offered objective quantification of changes in joint angle after each sonication, and these findings were consistent with clinical judgments of tremor response. These results suggest that this technique could be used for fine adjustment of the location of sonication energy and number of sonications to consistently achieve optimal tremor reduction.