Biomechanical comparison of two different compression screws for the treatment of odontoid fractures in human dens axis specimen.

BACKGROUND: Lag screw osteosynthesis for odontoid fractures has a high rate of pseudoarthrosis, especially in elderly patients. Besides biomechanical properties of the different screw types, insufficient fragment compression or unnoticed screw stripping may be the main causing factors for this adverse event. The aim of the study was to compare two screws in clinical use with different design principles in terms of compression force and stability against screw stripping. METHODS: Twelve human cadaveric C2 vertebral bodies were considered. Bone density was determined. The specimens were matched according to bone density and randomly assigned to two experimental groups. An odontoid fracture was induced, which were fixed either with a 3.5 mm standard compression screw or with a 5 mm sleeve nut screw. Both screws are certified for the treatment of odontoid fractures. The bone samples were fixed in a measuring device. The screwdriver was driven mechanically. The tests were analyzed for peak interfragmentary compression and screw-in torque with a frequency of 20 Hz. FINDINGS: The maximum fragment compression was significantly higher with screw with sleeve nut at 346.13(SD ±72.35) N compared with classic compression screw at 162.68(SD ±114.13) N (p = 0.025). Screw stripping occurred significantly earlier in classic compression screw at 255.5(SD ±192.0)° rotation after reaching maximum compression than in screw with sleeve nut at 1005.2(SD ±341.1)° (p = 0.0039). INTERPRETATION: Screw with sleeve nut achieves greater fragment compression and is more robust to screw stripping compared to classic compression screw. Whether the better biomechanical properties lead to a reduction of pseudoarthrosis has to be proven in clinical studies.

Serum Biomarkers of a Pro-Neuroinflammatory State May Define the Pre-Operative Risk for Postoperative Delirium in Spine Surgery.

Advances in spine surgery enable technically safe interventions in older patients with disabling spine disease, yet postoperative delirium (POD) poses a serious risk for postoperative recovery. This study investigates biomarkers of pro-neuroinflammatory states that may help objectively define the pre-operative risk for POD. This study enrolled patients aged ≥60 scheduled for elective spine surgery under general anesthesia. Biomarkers for a pro-neuroinflammatory state included S100 calcium-binding protein ß (S100ß), brain-derived neurotrophic factor (BDNF), Gasdermin D, and the soluble ectodomain of the triggering receptor expressed on myeloid cells 2 (sTREM2). Postoperative changes of Interleukin-6 (IL-6), Interleukin-1ß (IL-1ß), and C-reactive protein (CRP) were assessed as markers of systemic inflammation preoperatively, intraoperatively, and early postoperatively (up to 48 h). Patients with POD (n = 19, 75.7 ± 5.8 years) had higher pre-operative levels of sTREM2 (128.2 ± 69.4 pg/mL vs. 97.2 ± 52.0 pg/mL, p = 0.049) and Gasdermin D (2.9 ± 1.6 pg/mL vs. 2.1 ± 1.4 pg/mL, p = 0.29) than those without POD (n = 25, 75.6 ± 5.1 years). STREM2 was additionally a predictor for POD (OR = 1.01/(pg/mL) [1.00-1.03], p = 0.05), moderated by IL-6 (Wald-χ2 = 4.06, p = 0.04). Patients with POD additionally showed a significant increase in IL-6, IL-1ß, and S100ß levels on the first postoperative day. This study identified higher levels of sTREM2 and Gasdermin D as potential markers of a pro-neuroinflammatory state that predisposes to the development of POD. Future studies should confirm these results in a larger cohort and determine their potential as an objective biomarker to inform delirium prevention strategies.

Duration of Surgery and Intraoperative Blood Pressure Management Are Modifiable Risk Factors for Postoperative Neurocognitive Disorders After Spine Surgery: Results of the Prospective CONFESS Study.

STUDY DESIGN: Prospective quasi-experimental observational study. OBJECTIVE: The objective of this study was to evaluate whether duration of surgery is a modifiable risk factor for postoperative delirium (POD) after spine surgery and explore further modifiable risk factors. In addition, we sought to investigate the association between POD and postoperative cognitive dysfunction and persistent neurocognitive disorders. SUMMARY OF BACKGROUND DATA: Advances in spine surgery enable technically safe interventions in elderly patients with disabling spine disease. The occurrence of POD and delayed neurocognitive complications ( e.g. postoperative cognitive dysfunction/persistent neurocognitive disorder) remain a concern since these contribute to inferior functional outcomes and long-term care dependency after spine surgery. MATERIALS AND METHODS: This prospective single-center study recruited patients aged 60 years or above and scheduled for elective spine surgery between February 2018 and March 2020. Functional (Barthel Index, BI) and cognitive outcomes [Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test battery; telephone Montréal Cognitive Assessment] were assessed at baseline, three (V3), and 12 months postoperatively. The primary hypothesis was that the duration of surgery predicts POD. Multivariable predictive models of POD included surgical and anesthesiological parameters. RESULTS: Twenty-two percent of patients developed POD (n=22/99). In a multivariable model, duration of surgery [OR adj =1.61/h (95% CI, 1.20-2.30)], age [OR adj =1.22/yr (95% CI, 1.10-1.36)], and baseline deviations of intraoperative systolic blood pressure [25th percentile: OR adj =0.94/mm Hg (95% CI, 0.89-0.99); 90th percentile: OR adj =1.07/mm Hg (95% CI, 1.01-1.14)] were significantly associated with POD. Postoperative cognitive scores generally improved (V3, ΔCERAD total z -score: 0.22±0.63). However, this positive group effect was counteracted by POD [beta: -0.87 (95% CI, -1.31 to 0.42)], older age [beta: -0.03/yr (95% CI, -0.05 to 0.01)], and lack of functional improvement [ΔBI; beta: -0.04/point (95% CI, -0.06 to 0.02)]. Cognitive scores at twelve months remained inferior in the POD group, adjusted for baseline cognition/age. CONCLUSIONS: This study identified distinct neurocognitive effects after spine surgery, which are influenced by perioperative risk factors. Potential cognitive benefits are counteracted by POD, rendering its prevention critical in an aging population.

Tear-drop technique in iliac screw placement: a technical analysis.

BACKGROUND: Instrumentation of the lumbosacral region is one of the more challenging regions due to the complex anatomical structures and biomechanical forces. Screw insertion can be done both navigated and based on X-ray verification. In this study, we demonstrate a fast and reliable open, low exposure X-ray-guided technique of iliac screw placement. METHODS: Between October 2016 and August 2019, 48 patients underwent sacropelvic fixation in tear-drop technique. Screw insertion was performed in open technique by using an X-ray converter angulated 25-30° in coronal and sagittal view. The anatomical insertion point was the posterior superior iliac spine. Verification of correct screw placement was done by intraoperative 3D scan. RESULTS: In total, 95 iliac screws were placed in tear-drop technique with a correct placement in 98.1%. CONCLUSIONS: The tear-drop technique showed a proper screw position in the intraoperative 3D scan and therefore may be considered an alternative technique to the navigated screw placement.

Biomechanical comparison of three different compression screws for treatment of odontoid fractures evaluation of a new screw design.

BACKGROUND: Lag screw osteosynthesis in odontoid fractures shows a high rate of pseudarthrosis. Biomechanical properties may play a role with insufficient fragment compression or unnoticed screw stripping. A biomechanical comparison of different constructed lag-screws was carried out and the biomechanical properties determined. METHODS: Two identical compression screws with different pilot holes (1.25 and 2.5 mm), a double-threaded screw and one sleeve-nut-screw were tested on artificial bone (Sawbone, densities 10-30pcf). Fragment compression and torque were continuously measured using thin-film force sensors (Flexiforce A201, Tekscan) and torque sensors (PCE-TM 80, PCE GmbH). FINDINGS: The lowest compression reached the double-threaded screw. Compression and sleeve-nut-screw achieved 214-298% and 325-546%, respectively, of the compression force of double-threaded-screw, depending on the test material. The pilot hole optimization led to a significant improvement in compression only in the densest test material. Screw stripping took place significantly later with increasing density of the test material on all screws. In compression screws this was done at a screw rotation of 180-270°, in sleeve nut screw at 270-720° and in double-threaded screws at 300-600° after reaching the maximum compression. INTERPRETATION: Double-threaded screw is robust against screw stripping, but achieves only low fragment compression. The classic compression screws achieve better compression, but are sensitive to screw stripping. Sleeve-nut screw is superior in compression and as robust as double-threaded screw against screw stripping. Whether the better biomechanical properties lead to a reduction in pseudarthrosis must be proven in clinical trials.

Correction: Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial.

[This corrects the article DOI: 10.2196/15488.].

Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial.

BACKGROUND: Elderly people are at particular high risk for postoperative delirium (POD) following spine surgery, which is associated with longer hospital stays, higher costs, risk for delayed complications, long-term care dependency, and cognitive dysfunction (POCD). It is insufficiently understood which mechanisms and risk factors contribute to the development of POD and POCD following these major but plannable surgeries. OBJECTIVE: This study aims to identify modifiable risk factors in spine surgery. A better understanding thereof would help adapt medical management and surgical strategies to individual risk profiles. METHODS: This is a single-center observational study jointly conducted by the departments of neurosurgery, neurology, and anesthesiology at a tertiary care hospital in Germany. All patients aged 60 years and older presenting to the neurosurgery outpatient clinic or ward for elective spine surgery are screened for eligibility. Exclusion criteria include presence of neurodegenerative or history of psychiatric disease and medication with significant central nervous system activity (eg, antidepressants, antipsychotics, sedatives). Surgical and anesthetic procedures including duration of surgery as primary end point of this study are thoroughly documented. All patients are furthermore evaluated for their preoperative cognitive abilities by a number of tests, including the Consortium to Establish a Registry for Alzheimer's Disease Plus test battery. Physical, mental, and social health and well-being are assessed using the Patient-Reported Outcome Measurement Information System Profile 29 and Hospital Anxiety and Depression Scale. Patients additionally receive preoperative cerebrovascular ultrasound and structural and functional brain imaging. The immediate postoperative period includes screening for POD using the Nursing Delirium Screening Scale and validation through Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. We furthermore investigate markers of (neuro)inflammation (eg, interleukins, C-reactive protein, tumor necrosis factor alpha). Preoperative examinations are repeated 3 months postoperatively to investigate the presence of POCD and its mechanisms. Statistical analyses will compare delirious and nondelirious patients for predictors of immediate (POD) and delayed (POCD) cognitive dysfunction. RESULTS: This is the first study to prospectively evaluate risk factors for POD and POCD in spine surgery. Recruitment is ongoing, and data collection is estimated to be finished with the inclusion of 200 patients by mid-2020. CONCLUSIONS: The identification of mechanisms, possibly common, underlying POD and POCD would be a major step toward defining effective interventional strategies early in or even before the postoperative period, including the adaptation of surgical strategies to individual risk profiles. TRIAL REGISTRATION: ClinicalTrials.gov NCT03486288; https://clinicaltrials.gov/ct2/show/NCT03486288. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/15488.

Neurostimulation in tardive dystonia/dyskinesia: A delayed start, sham stimulation-controlled randomized trial.

INTRODUCTION: Growing evidence suggests that pallidal deep brain stimulation represents a potential new therapeutic avenue in tardive dystonia/dyskinesia, but controlled and blinded randomized studies (RCT) are missing. The present RCT compares dystonia/dyskinesia severity of pallidal neurostimulation in patients with tardive dystonia using a delayed-start design paradigm. METHODS: Dystonia/dyskinesia severity was assessed via blinded videos following pallidal neurostimulation at 3 (blinded phase) and 6 months (open extension phase). Primary endpoint was the percentage change of dystonia severity (Burke-Fahn-Marsden-Dystonia-Rating-Scale, BFMDRS) at 3 months between active vs. sham neurostimulation using blinded-video assessment. Secondary endpoints comprised clinical rating scores for movement disorders. Clinicaltrials.gov NCT00331669. RESULTS: Twenty-five patients were randomized (1:1) to active (n = 12) or sham neurostimulation (n = 13). In the intention-to-treat analyses the between group difference of dystonia severity (BFMDRS) between active vs. sham stimulation was not significant at 3 months. Three months post-randomisation dystonia severity improved significantly within the neurostimulation by 22.8% and non-significantly within the sham group (12.0%) compared to their respective baseline severity. During the open-label extension with both groups being actively treated, significant and pronounced improvements of 41.5% were observed via blinded evaluation. Adverse events (n = 10) occurred in 10/25 of patients during the 6 months, mostly related to surgical implantation of the device; all resolved without sequelae. CONCLUSION: The primary endpoint of this randomized trial was not significant, most likely due to incomplete recruitment. However, pronounced improvements of most secondary endpoints at 3 and 6 months provide evidence for efficacy and safety of pallidal neurostimulation in tardive dystonia.

A radiological and anatomic examination of intralaminar screws in the thoracic spine-a theoretical feasibility study.

BACKGROUND: Failure of pedicle screws and anatomical variations which prevent pedicle screw implantation make the search for an alternative to pedicle screws in thoracic spine surgery necessary. To date, published data have shown that intralaminar screws could be a possible way of fixation. Object of this study is a systematic examination of the feasibility of lamina screws in the whole thoracic spine. METHODS: Fifty females and 50 males (age 20 to 60 years) who underwent a polytrauma CT from 2010 to 2012 were randomly selected. Patients with injury of the thoracic spine, trauma-independent deformity, or dysplasia of the thoracic spine were excluded. A three-dimensional reconstruction of the thoracic spine was performed from the data set. The anatomical data of the lamina were measured under consideration of the potential trajectory of a laminar screw. The caliber of the corresponding pedicle was measured as well. RESULTS: The diameters of the lamina show a decline in superior-inferior direction (0.66 cm in T1 to 0.60 cm in T12 in males, 0.62 to 0.56 cm in females). Diameters of pedicle and lamina show no correlation. Twenty percent of the pedicles have a hypoplasia with a diameter of less than 0.5 cm. However, in these vertebrae, 62.3% of the laminae would be suitable for 0.4-cm lamina screws. Only in 2.75% of the vertebral bodies, there was no possibility for intralaminar or pedicle screws. CONCLUSIONS: This study shows that it is possible to use intralaminar screws in the thoracic spine in most of patients.

Surgical management of an adult manifestation of Ewing sarcoma of the spine-a case report.

Ewing sarcoma (ES) is a primary malignant bone tumor. Its occurrence in adults is uncommon. Even rarer is the occurrence in the spine. The prognosis of this tumor in adult patients is unfavorable. In this report, we present the case of a 56-year-old woman with ES localized at the upper thoracic spine, presented with acute incomplete paraplegia. The patient underwent emergency decompressive hemilaminectomy and tumor debulking surgery to decompress the spinal cord. As adjuvant therapy, she received radio-chemotherapy followed by en bloc resection via a combined dorsoventral approach. In the course of the disease, the patient showed a continuous neurological improvement from AISA B to E over the follow up period of 18 months. To date there has been no evidence of tumor recurrence. We report our experience in treating ES of the spine in an adult patient presenting with neurological deficits. We highlight the advantage of en bloc resection of the tumor after spinal stabilization to treat the local disease and alleviating the presenting symptoms.

Incidence of unexpected positive histology in kyphoplasty.

OBJECTIVE: Kyphoplasty and vertebroplasty have become one of the most frequent surgical procedures in the treatment of vertebral compression fractures. Often, the cause of compression fractures is lowered bone mineral density as in osteoporosis. In the differential workup, also pathologic vertebral compression fractures need to be ruled out. Importantly, imaging techniques alone cannot safely differentiate between invasive lymphatic and osteoporotic vertebral fracture. Our goal was to identify the degree of unexpected positive histology in kyphoplasty for presumed osteoporotic vertebral compression fracture. METHODS: We retrospectively analyzed all kyphoplasties performed between 2007 and 2015 at our institution. The data were acquired by reviewing our medical documentation system. The data analysis was done using Microsoft Excel. The statistical analysis was done using the Chi-squared test. RESULTS: We performed 130 kyphoplasties/vertebroplasties. A biopsy was taken in 97 (74.6%) cases. In 10 (10.3%) cases, the histology revealed a pathological fracture. From these patients, only in 3 (30%) cases, a positive histology was not expected. Meaning that there was no history of cancer and the radiological findings presumed an osteoporotic fracture. CONCLUSIONS: Therefore, we could demonstrate that the incidence of unexpected positive histology in vertebral compression fracture treated with kyphoplasty is significant (3.1%). As a conclusion, if a kyphoplasty is performed due to assumed osteoporotic vertebral compression fracture, a biopsy should be taken to safely rule out a pathological fracture caused by lymphatic bony invasion.

Heat Generation During Bony Decompression of Lumbar Spinal Stenosis Using a High-Speed Diamond Drill with or without Automated Irrigation and an Ultrasonic Bone-Cutting Knife: A Single-Blinded Prospective Randomized Controlled Study.

OBJECTIVE: The main objective of the present prospective, randomized, single-blinded controlled study was to measure heat during bony decompression of lumbar spinal stenosis with high-speed drills and an ultrasonic bone-cutting knife. METHODS: Ninety patients diagnosed with lumbar spinal stenosis were included in this study and randomized for lumbar spinal canal decompression using either a high-speed drill with automatic irrigation, high-speed drill with manual irrigation, or an ultrasonic bone-cutting knife with automatic irrigation (USBCD). For evaluation of group homogeneity, a visual analog scale pain score and neurologic findings were measured preoperatively and postoperatively. Temperatures during bony decompression were measured using a forward-looking infrared camera system. RESULTS: Clinical results among the 3 groups did not differ in pain reduction, improvement of neurologic findings, or the rate of complications. However, significantly lower values were found for absolute and mean maximal temperatures during bony decompression in the USBCD group compared with the groups of patients who received the high-speed drill with automatic irrigation and the high-speed drill with manual irrigation, indicating this technique to be less aggressive in terms of thermal induction of bone necrosis. USBCD allows more precise bone removal compared with high-speed drills, and despite increased device time, no significant difference in the overall decompression time was observed. CONCLUSIONS: All methods examined produced short temperature peaks with possible, at least temporary, damage to bone and neural tissue. Automatic irrigation was associated with lower heat development compared with manual irrigation. Despite evidence of critical temperatures, no clinical correlation (e.g., neurologic deficits) was encountered in this study. Clinically, all 3 methods presented equally good results.

Neuronavigation and 3D fluoroscopy-guided lag screw reduction and osteosynthesis for traumatic spondylolistheses of the axis: a path worth exploring?

OBJECTIVE In traumatic spondylolistheses of the axis, there is a marked heterogeneity of the observed injury patterns, with a wide range of the severity-from stable fractures, which can be treated conservatively with very good success, to highly unstable fractures, which should be treated surgically. A number of classification systems have been devised to assess the instability of the injuries and to derive a corresponding therapy recommendation. In particular, the results and recommendations regarding medium-severity cases are still inconclusive. Minimally invasive percutaneous procedures performed using modern techniques such as 3D fluoroscopy and neuronavigation have the potential for improvements in the therapeutic outcome and procedural morbidity against open surgical procedures and conservative therapy. METHODS A minimally invasive method using 3D fluoroscopy and neuronavigation for percutaneous lag screw osteosynthesis of the pars interarticularis was performed in 12 patients with a Levine-Edwards Type II fracture. Ten patients had an isolated hangman's fracture and 2 patients had an additional odontoid fracture of the axis (Type II according to the Anderson and D'Alonzo classification system). Complications, operating parameters, screw positions, and bony fusion were evaluated for the description and evaluation of the technique. RESULTS In 6 men and 6 women, percutaneous lag screw osteosynthesis was performed successfully. Correct placement could be verified postoperatively for all inserted screws. In the case series, nonunion was not observed. In all patients with a complete follow-up, a bony fusion, an intact vertebral alignment, and no deformity could be detected on CT scans obtained after 3 months. CONCLUSIONS The percutaneous pars interarticularis lag screw osteosynthesis is a minimally invasive and mobility-preserving surgical technique. Its advantages over alternative methods are its minimal invasiveness, a shortened treatment time, and high fusion rates. The benefits are offset by the risk of injury to the vertebral arteries. The lag screw osteosynthesis is only possible with Levine-Edwards Type II fractures, because the intervertebral joints to C-3 are functionally preserved. A further development and evaluation of the operative technique as well as comparison with conservative and alternative surgical treatment options are deemed necessary.

3-Tesla Kinematic MRI of the Cervical Spine for Evaluation of Adjacent Level Disease After Monosegmental Anterior Cervical Discectomy and Arthroplasty: Results of 2-Year Follow-Up.

STUDY DESIGN: We prospectively evaluated adjacent disc levels after anterior cervical discectomy and arthroplasty (ACDA) using kinematic magnetic resonance imaging (MRI) and plain functional radiographs. OBJECTIVE: ACDA is an established treatment for degenerative cervical disc disease. The objective of this study was to evaluate the use of kinematic MRI for assessing the range of motion (ROM) before and after ACDA compared with plain functional radiographs and to evaluate adjacent degenerative disc disease (aDDD) at mid-term follow-up. SUMMARY OF BACKGROUND DATA: Twenty patients (12 females, 8 males; median age 45.6 ±â€Š6.9 yrs) treated by ACDA (BryanDisc; Medtronic, MN) underwent plain functional radiography and kinematic MRI of the cervical spine at 3 T before and 6 and 24 months after surgery. METHODS: A sagittal T2-weighted (T2w) 2D turbo spin echo (TSE) sequence and a 3D T2w dataset with secondary axial reconstruction were acquired. Signal intensity of all nonoperated discs was measured in regions of interest (ROI). Disc heights adjacent to the operated segment were measured. ROM was evaluated and compared with plain functional radiographs. Clinical outcome was evaluated using the visual analog scale (VAS) for head, neck and radicular pain, and the neck disability index (NDI). RESULTS: Mean ROM of the cervical spine on functional plain radiographs was 21.25 ±â€Š8.19°, 22.29 ±â€Š4.82°, and 26.0 ±â€Š6.9° preoperatively and at 6-month and 24-month follow-up, respectively. Mean ROM at MRI was 27.1 ±â€Š6.78°, 29.45 ±â€Š9.51°, and 31.95 ±â€Š9.58°, respectively. There was a good correlation between both techniques. Follow-up examinations demonstrated no signs of progressive degenerative disc disease of adjacent levels. All patients had clinical improvement up to 24 months after surgery. CONCLUSION: After ACDA, kinematic MRI allows evaluation of the ROM with excellent correlation to plain functional radiographs. Mid-term follow-up after ACDA is without evidence of progressive DDD of adjacent segments. LEVEL OF EVIDENCE: 3.

Magnetic resonance-transcranial ultrasound fusion imaging: A novel tool for brain electrode location.

BACKGROUND: A combination of preoperative magnetic resonance imaging (MRI) with real-time transcranial ultrasound, known as fusion imaging, may improve postoperative control of deep brain stimulation (DBS) electrode location. Fusion imaging, however, employs a weak magnetic field for tracking the position of the ultrasound transducer and the patient's head. Here we assessed its feasibility, safety, and clinical relevance in patients with DBS. METHODS: Eighteen imaging sessions were conducted in 15 patients (7 women; aged 52.4 ± 14.4 y) with DBS of subthalamic nucleus (n = 6), globus pallidus interna (n = 5), ventro-intermediate (n = 3), or anterior (n = 1) thalamic nucleus and clinically suspected lead displacement. Minimum distance between DBS generator and magnetic field transmitter was kept at 65 cm. The pre-implantation MRI dataset was loaded into the ultrasound system for the fusion imaging examination. The DBS lead position was rated using validated criteria. Generator DBS parameters and neurological state of patients were monitored. RESULTS: Magnetic resonance-ultrasound fusion imaging and volume navigation were feasible in all cases and provided with real-time imaging capabilities of DBS lead and its location within the superimposed magnetic resonance images. Of 35 assessed lead locations, 30 were rated optimal, three suboptimal, and two displaced. In two cases, electrodes were re-implanted after confirming their inappropriate location on computed tomography (CT) scan. No influence of fusion imaging on clinical state of patients, or on DBS implantable pulse generator function, was found. CONCLUSIONS: Magnetic resonance-ultrasound real-time fusion imaging of DBS electrodes is safe with distinct precautions and improves assessment of electrode location. It may lower the need for repeated CT or MRI scans in DBS patients.

Pallidal neurostimulation in patients with medication-refractory cervical dystonia: a randomised, sham-controlled trial.

BACKGROUND: Cervical dystonia is managed mainly by repeated botulinum toxin injections. We aimed to establish whether pallidal neurostimulation could improve symptoms in patients not adequately responding to chemodenervation or oral drug treatment. METHODS: In this randomised, sham-controlled trial, we recruited patients with cervical dystonia from centres in Germany, Norway, and Austria. Eligible patients (ie, those aged 18-75 years, disease duration ≥3 years, Toronto Western Spasmodic Torticollis Rating Scale [TWSTRS] severity score ≥15 points) were randomly assigned (1:1) to receive active neurostimulation (frequency 180 Hz; pulse width 120 µs; amplitude 0·5 V below adverse event threshold) or sham stimulation (amplitude 0 V) by computer-generated randomisation lists with randomly permuted block lengths stratified by centre. All patients, masked to treatment assignment, were implanted with a deep brain stimulation device and received their assigned treatment for 3 months. Neurostimulation was activated in the sham group at 3 months and outcomes were reassessed in all patients after 6 months of active treatment. Treating physicians were not masked. The primary endpoint was the change in the TWSTRS severity score from baseline to 3 months, assessed by two masked dystonia experts using standardised videos, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00148889. FINDINGS: Between Jan 19, 2006, and May 29, 2008, we recruited 62 patients, of whom 32 were randomly assigned to neurostimulation and 30 to sham stimulation. Outcome data were recorded in 60 (97%) patients at 3 months and 56 (90%) patients at 6 months. At 3 months, the reduction in dystonia severity was significantly greater with neurostimulation (-5·1 points [SD 5·1], 95% CI -7·0 to -3·5) than with sham stimulation (-1·3 [2·4], -2·2 to -0·4, p=0·0024; mean between-group difference 3·8 points, 1·8 to 5·8) in the intention-to-treat population. Over the course of the study, 21 adverse events (five serious) were reported in 11 (34%) of 32 patients in the neurostimulation group compared with 20 (11 serious) in nine (30%) of 30 patients in the sham-stimulation group. Serious adverse events were typically related to the implant procedure or the implanted device, and 11 of 16 resolved without sequelae. Dysarthria (in four patients assigned to neurostimulation vs three patients assigned to sham stimulation), involuntary movements (ie, dyskinesia or worsening of dystonia; five vs one), and depression (one vs two) were the most common non-serious adverse events reported during the course of the study. INTERPRETATION: Pallidal neurostimulation for 3 months is more effective than sham stimulation at reducing symptoms of cervical dystonia. Extended follow-up is needed to ascertain the magnitude and stability of chronic neurostimulation effects before this treatment can be recommended as routine for patients who are not responding to conventional medical therapy. FUNDING: Medtronic.

Pallidal deep brain stimulation in patients with primary generalised or segmental dystonia: 5-year follow-up of a randomised trial.

BACKGROUND: Severe forms of primary dystonia are difficult to manage medically. We assessed the safety and efficacy of pallidal neurostimulation in patients with primary generalised or segmental dystonia prospectively followed up for 5 years in a controlled multicentre trial. METHODS: In the parent trial, 40 patients were randomly assigned to either sham neurostimulation or neurostimulation of the internal globus pallidus for a period of 3 months and thereafter all patients completed 6 months of active neurostimulation. 38 patients agreed to be followed up annually after the activation of neurostimulation, including assessments of dystonia severity, pain, disability, and quality of life. The primary endpoint of the 5-year follow-up study extension was the change in dystonia severity at 3 years and 5 years as assessed by open-label ratings of the Burke-Fahn-Marsden dystonia rating scale (BFMDRS) motor score compared with the preoperative baseline and the 6-month visit. The primary endpoint was analysed on an intention-to-treat basis. The original trial is registered with ClinicalTrials.gov (NCT00142259). FINDINGS: An intention-to-treat analysis including all patients from the parent trial showed significant improvements in dystonia severity at 3 years and 5 years compared with baseline, which corresponded to -20·8 points (SD 17·1; -47·9%; n=40) at 6 months; -26·5 points (19·7; -61·1%; n=31) at 3 years; and -25·1 points (21·3; -57·8%; n=32). The improvement from 6 months to 3 years (-5·7 points [SD 8·4]; -34%) was significant and sustained at the 5-year follow-up (-4·3 [10·4]). 49 new adverse events occurred between 6 months and 5 years. Dysarthria and transient worsening of dystonia were the most common non-serious adverse events. 21 adverse events were rated serious and were almost exclusively device related. One patient attempted suicide shortly after the 6-month visit during a depressive episode. All serious adverse events resolved without permanent sequelae. INTERPRETATION: 3 years and 5 years after surgery, pallidal neurostimulation continues to be an effective and relatively safe treatment option for patients with severe idiopathic dystonia. This long-term observation provides further evidence in favour of pallidal neurostimulation as a first-line treatment for patients with medically intractable, segmental, or generalised dystonia. FUNDING: Medtronic.

Sudden intraaqueductal dislocation of a third ventricle ependymoma causing acute decompensation of hydrocephalus.

The authors report an unusual sudden intraaqueductal dislocation of a third ventricle ependymoma causing acute loss of consciousness, and they detail its neuroendoscopic treatment. This case is unique and has never been described in the literature before. The patient suffered from headache and recurrent nausea. Admission MR images revealed a contrast-enhancing lesion within the posterior part of the third ventricle. During the course of the day of admission, the patient suddenly became comatose. Emergency MR imaging demonstrated a deeply intraaqueductal dislocation of the pedicled tumor, with complete obstruction of the aqueduct and ventricular dilation. Immediate surgical intervention with endoscopic third ventriculostomy and complete tumor removal was performed. After surgery, the patient made a rapid recovery. In this case, the authors presume a sudden intraaqueductal dislocation of the ependymoma caused by aspiration of the tumor as a result of the caudal CSF flow.

Transcranial sonographic localization of deep brain stimulation electrodes is safe, reliable and predicts clinical outcome.

In patients with deep brain stimulation (DBS), poor postoperative outcome or unexpected clinical change require brain imaging to check the lead location. Here, we studied safety, reliability and prognostic value of transcranial sonography (TCS) for DBS lead localization applying predefined TCS criteria. After measuring thermal effects of TCS and imaging artefact sizes of DBS lead using a skull phantom, we prospectively enrolled 34 patients with DBS of globus pallidus internus, ventro-intermediate thalamic or subthalamic nucleus. TCS had no influence on lead temperature, electrical parameters of DBS device or clinical state of patients. TCS measures of lead coordinates agreed with MRI measures in anterior-posterior and medial-lateral axis. Lead dislocation requiring reinsertion was reliably detected. Only patients with optimal lead position on TCS had favorable clinical 12-month outcome (>50% improvement), whereas unfavorable outcome (<25% improvement) was associated with suboptimal lead position. TCS may therefore become a first-choice modality to monitor lead location.

Deep brain stimulation in dystonia: sonographic monitoring of electrode placement into the globus pallidus internus.

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective treatment in primary dystonia. Its success depends on the implantation accuracy of the DBS electrode into the targeted GPi. Discrepancies of up to 4 mm between the initial target, selected on preoperative MRI, and the final DBS lead location are caused mainly by caudal brain shift that occurs once the cranium is open. Nowadays, transcranial sonography (TCS) can display echogenic deep brain structures with higher image resolution compared to MRI under clinical conditions. Here, we demonstrate for the first time the use of a contemporary clinical high-end TCS system for intraoperative monitoring of DBS electrode position. Herewith, a high-resolution real-time imaging of closely located microelectrodes and of the DBS lead through the intact skull is feasible. Simultaneous color-coded sonographic imaging of arteries near the anatomical target allows further intraoperative refinement of DBS lead positioning, simultaneously preventing hemorrhages.