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OBJECTIVE The choice of surgical technique in sight-threatening Grave orbitopathy remains controversial. Available data are mostly derived from mixed cohorts with multiple surgical indications and techniques. The authors assessed predictors for visual outcome after standardized pterional orbital decompression for dysthyroid optic neuropathy. METHODS Retrospective analysis of 62 pterional orbital decompressions performed on 40 patients with dysthyroid optic neuropathy. RESULTS Visual acuity improved by an average of 3.8 lines in eyes with preoperative visual impairment (95% confidence interval [CI]: 1.8-5.8 lines, P < 0.001) and remained stable in eyes without prior visual impairment (95% CI -1.3 to 1 line, P = 0.81). Proptosis was reduced by an average of 3.1 mm (95% CI 1.8-4.3 mm, P < 0.001). Higher degrees of proptosis were predictive of worse visual outcomes (P = 0.017). New-onset diplopia developed in 2 patients, while previous diplopia resolved after surgery in 6 patients. CONCLUSIONS This cohort is the largest series of pterional orbit decompressions and the first to focus exclusively on dysthyroid neuropathy. Complication rates were low. Decompression surgery was highly effective at restoring and maintaining visual acuity in patients with dysthyroid optic neuropathy.

STUDY DESIGN Prospective, observational study. OBJECTIVE The aim of this study was to collect objective and especially subjective data on changes in cervical spine mobility after single-level anterior cervical decompression and fusion (ACDF) and to investigate the impact on quality of life and activities of daily living (ADLs). SUMMARY OF BACKGROUND DATA Although there are several studies dealing with the objective change in mobility after single-level ACDF, there are few data on how spondylodesis of a motion segment affects subjective restriction of cervical spine mobility. METHODS Patients undergoing first-time, single-level ACDF for a symptomatic spondylotic process were eligible. Data were collected before surgery, at 3-month, and 1-year follow-up. Patients were assessed via clinical scores (pain intensity, Short-Form 8 [SF-8], among others) and asked for impairment in ADLs due to restriction of cervical spine mobility. The subjective restriction was acquired by a five-step patient-reported score. The range of motion was measured by the CROM device. RESULTS Data of 97 patients could be evaluated. For pain scores and SF-8 there were significant improvements 3 months and 1 year after surgery (P

Study design A randomized controlled trial. Objective To compare the radiation exposure with the scrub nurse, assistant surgeon, and anesthetist during minimally invasive transforaminal lumbar interbody fusion using conventional 2-dimensional (2D) fluoroscopy or 3D fluoroscopy-based navigation. Summary of background data Minimally invasive spinal fusion techniques are related to higher radiation exposures compared with open techniques. Especially the routinely exposed surgical staff faces the risks of increased radiation exposure. Methods In total, 41 patients with planned monosegmental minimally invasive transforaminal lumbar interbody fusion were randomized into the intraoperative imaging techniques 2D fluoroscopy or 3D navigation. Eye lens and film dosemeters were attached to defined locations of the scrub nurse, assistant surgeon, and anesthetist. Mann-Whitney U and Wilcoxon-matched pairs signed-rank test were used to compare dosemeter readings. This study was registered with the German Clinical Trials Register (DRKS00004514). Results The radiation exposure per surgery was low for the scrub nurse, assistant surgeon, and anesthetist in both the 2D fluoroscopy and 3D navigation groups. The maximum average value of 0.057±0.031 mSv was measured on the unprotected chest of the assistant surgeon and was thus slightly above the lower detection limit of the dosemeters (0.044 mSv). The annual occupational dose limit would be exceeded at the earliest after 571 operations for the unprotected eye lens of the assistant surgeon. Conclusions Minimally invasive lumbar fusion surgery is possible with comparatively low radiation exposure to the assisting operating room personnel without exceeding the annual maximum occupational radiation exposure. However, there is no definite dose value below which ionizing radiation poses no risk. Consequently, radiation sparing work routines should be strictly followed.

The two middle contacts of directional leads (d-leads) for deep brain stimulation are split into three segments, allowing current steering toward desired axial directions. To facilitate programming, their final orientation needs to be reliably determined. However, it is currently unclear whether d-leads rotate after implantation. Our objective was to assess the degree of d-lead rotation after implantation. We retrospectively analyzed d-lead orientation on intraoperative X-rays, postoperative CT scans (latencies to surgery: 108–189 min postoperatively), and rotational fluoroscopies (4–9 days postoperatively) for a consecutive series of 32 implanted d-leads. For five d-leads, a CT scan with a mean follow-up of 57 days (range 28–182) was available. All d-leads were implanted with the marker facing anterior and the intention to hit an “iron sight” (ISi) on the X-ray, indicating anterior orientation (i.e., 0° ± 6°). In nine d-leads, an ISi was visible on the final X-ray; median orientation was 1.5° (range 0.5–6.0°) at the first follow-up CT, confirming anterior orientation. In d-leads without ISi or where ISi was not evaluable, the median rotation was 15.5° (9.5–35.0°) and 26.5° (5.5-62.0°), respectively. The orientation of the initial CT was comparable with the orientation determined by the postoperative rotational fluoroscopy and second CT in all d-lead groups. D-lead orientation does not change within the first week after implantation. We provide first indications that d-lead orientation remains stable for several weeks after surgery. Determination of lead orientation using marker-based X-ray alone seems too imprecise; adding the ISi method can increase determination of intraoperative orientation.

Study design Randomized controlled trial. Objective The aim of this study was to compare the dosemetrically determined radiation exposure of surgeon and patient during minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) using conventional 2D fluoroscopy (FLUORO) or 3D fluoroscopy-based navigation (NAV). Summary of background data MIS TLIF was shown to exhibit higher radiation exposures compared to open techniques. In particular, the routinely exposed surgeon encounters the risks of increased radiation doses. With the additional use of intraoperative 3D navigation, major steps of the operation can be performed without exposing the operating room staff to ionizing radiation. Methods Forty-four patients undergoing monosegmental MIS TLIF were randomized into the two intraoperative imaging technique groups (FLUORO or NAV). The primary endpoint was the radiation exposure of the surgeon; the secondary endpoints were the radiation exposure of the patient and C-arm readings. Results After exclusion of three patients, 41 patients were analyzed. In general, the average radiation exposure of the surgeon was lower in the NAV group without being statistically significant. The radiation exposure of the patient was significantly higher in the NAV group at all dosemeter sites. The average fluoroscopy time was 63 ± 36 versus 109 ± 31 sec (FLUORO versus NAV group, P Conclusion The additional use of intraoperative 3D fluoroscopy-based navigation compared to conventional 2D fluoroscopy alone showed a nonsignificant reduction of the radiation exposure of the surgeon in monosegmental MIS TLIF, while increasing the radiation exposure of the patient. Level of evidence 1.

Objectives The negative effects of obesity on the health and quality of life of those afflicted has become an important public concern. Previous studies have shown an association between obesity and higher rates of complications and unfavorable outcomes following spine surgery. This study is to identify peri- and postoperative complication rates as well as short-term and long-term outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) in comparison to age-matched normal-weight patients. Patients and methods We retrospectively reviewed medical records for all adult patients with a body mass index (BMI) ≥40 kg/m2 who underwent 1- to 2-level MIS TLIF for degenerative disease between February 2009 and February 2014 at a single institution and compared them to age-matched normal-weight patients (BMI 20–25 kg/m2). Duration of operation, length of hospital stay, use of analgesics, minor and major complications (infections and re-operations) as well as postoperative pain reduction within 30 days of surgery were recorded. Furthermore, we collected long-term follow-up data (>1 year) regarding complications and pain reduction. Results We identified 14 patients with a BMI ≥ 40 kg/m2 (mean, 43.2 kg/m2) who underwent MIS TLIF. Both groups showed comparable complication rates and clinical results in the short term ( Conclusion MIS TLIF is technically feasible in morbidly obese patients with no evidence of higher complication rates among this demographic compared to normal-weight individuals when followed-up in the short-term (

Study Design: Prospective cohort study. Objectives: The purpose of this prospective study was to evaluate a protocol for radiation-sparing kyphoplasty by assessing dosemetrically recorded radiation exposures to both patient and surgeon. Methods: This prospective clinical study examines the radiation exposure to patient and surgeon during single-level kyphoplasty in 32 thoracolumbar osteoporotic vertebral body fractures (12 OF 2, 9 OF 3, 11 OF 4 types) using a radiation aware surgical protocol between May 2017 and November 2019. The radiation exposure was measured at different locations using film, eye lens and ring dosemeters. Dose values are reported under consideration of lower detection limits of each dosemeter type. Results: A high proportion of dosemeter readings was below the lower detection limits, especially for the surgeon (>90%). Radiation exposure to the surgeon was highest at the unprotected thyroid gland (0.053 ± 0.047 mSv), however only slightly above the lower detection limit of dosemeters (0.044 mSv). Radiation exposure to the patient was highest at the chest (0.349 ± 0.414 mSv) and the gonad (0.186 ± 0.262 mSv). Fluoroscopy time, dose area product and number of fluoroscopic images were 46.0 ± 17.9 sec, 124 ± 109 cGy×cm2, and 35 ± 13 per kyphoplasty, respectively. Back pain significantly improved from 6.8 ± 1.6 to 2.5 ± 1.7 on the numeric rating scale on the first postoperative day ( P < 0.0001). Conclusions: The implementation of a strict intraoperative radiation protection protocol allows for safely performed kyphoplasty with ultra-low radiation exposure for the patient and surgeon without exceeding the annual occupational dose limits. Trial registration: The study was registered in the German Clinical Trials Register (DRKS00011908, registration date 16/05/2017).

Background Laminectomy and multilevel fusion in patients with degenerative cervical myelopathy lead to severe restriction in cervical spine mobility. Since fusions from C2 to the thoracic spine result in a permanently stiff subaxial cervical spine, it seems obvious to restore physiological cervical lordosis, especially with regard to sagittal balance. However, there are reports that a fusion in a more lordotic position leads to a reduction of rotational cervical range of motion in the still mobile segments C0-C2. This study investigates the relationship between postoperative cervical lordosis and the objective rotational range of motion and subjective restriction. Methods In this single-center, retrospective cohort study, patients with degenerative cervical myelopathy operated via laminectomy and fusion from C2 to the thoracic spine were included. X-ray imaging was evaluated for common lordosis parameters. The patient-reported rotational restriction of cervical spine mobility was acquired by a five-step score. Objective rotational range of motion was measured. The radiological parameters for cervical lordosis (C2-C7 lordotic angle, C2-C7 Cobb angle) were correlated with the measurements and the patient-reported subjective scores. Findings We found a significant, medium negative correlation between the measurements for rotation and the C2-C7 lordotic angle and a significant, large negative correlation to the C2-C7 Cobb angle. For subjective restriction, no or only small correlation was observed. Interpretation We found significant negative correlations between radiological cervical lordosis and objective measurements for rotation. These results indicate that for this particular patient population, a stronger postoperative cervical lordosis does not seem favorable under the aspect of rotational range of motion.

The annual limit value for the eye lens dose for occupationally exposed personnel has recently been considerably reduced from 150mSv to 20mSv. We have therefore re-evaluated the effectiveness of radiation protection measures (lead glass goggles, mobile radiation shielding wall and distance to the radiation source) in an experimental setting to provide spinal surgeons with clearly understandable radiation dose data for their daily work.

For patients with multilevel degenerative cervical myelopathy (DCM), laminectomy and fusion is an established technique. A concomitant effect of multilevel fusion is a restriction of cervical spine mobility. This retrospective study on DCM-patients with at least 4 laminectomy and fusion levels, compares data between objective and subjective restriction of the postoperative cervical spine mobility. The patient-reported restriction of cervical spine mobility was acquired by a five-step score. Measurements of cervical range of motion were performed using the CROM device and were correlated with the subjective scores. Fusion was performed over 6 levels in most of the 36 patients. For the subjective cervical spine mobility, 52.8% reported none to medium, 38.9% severe and 8.3% complete restriction. Mean objective cervical range of motion was 45.0° for flexion-extension, 26.3° for total lateral flexion and 51.4° for total rotation and therefore evidently reduced compared to non-operated patient cohorts in literature. There was a significant medium, negative correlation between the objective measurements and the patient-reported general restriction of cervical spine mobility, and with the physical component summary of SF-8. The significant objective reduction of cervical range of motion after laminectomy and multilevel fusion correlates with the patient-reported assessment for general restriction.

Automatic anatomical segmentation of patients’ anatomical structures and modeling of the volume of tissue activated (VTA) can potentially facilitate trajectory planning and post-operative programming in deep brain stimulation (DBS). We demonstrate an approach to evaluate the accuracy of such software for the ventral intermediate nucleus (VIM) using directional leads. In an essential tremor patient with asymmetrical brain anatomy, lead placement was adjusted according to the suggested segmentation made by the software (Brainlab). Postoperatively, we used directionality to assess lead placement using side effect testing (internal capsule and sensory thalamus). Clinical effects were then compared to the patient-specific visualization and VTA simulation in the GUIDE™ XT software (Boston Scientific). The patient’s asymmetrical anatomy was correctly recognized by the software and matched the clinical results. VTA models matched best for dysarthria (6 out of 6 cases) and sensory hand side effects (5/6), but least for facial side effects (1/6). Best concordance was observed for the modeled current anterior and back spread of the VTA, worst for the current side spread. Automatic anatomical segmentation and VTA models can be valuable tools for DBS planning and programming. Directional DBS leads allow detailed postoperative assessment of the concordance of such image-based simulation and visualization with clinical effects.

Background Neuropathic dental pain (NDP) is a chronic pain condition that is notoriously difficult to treat. To date, there are no deep brain stimulation (DBS) studies on this specific pain condition and no optimal target or "sweet spot" has ever been defined. Objective To determine the optimal thalamic target for improving this condition by utilizing the steering abilities of a directional DBS electrode (Vercise CartesiaTM Model DB-2202-45, Boston Scientific). Methods A literature search and review of our database identified 3 potential thalamic targets. A directional lead was implanted in a patient with NDP and its current steering used to test the effects in each nucleus. The patient reported her pain after 2 wk of stimulation in a prospective randomized blinded trial of one. Quality of life measurements were performed before and after 3 mo on their best setting. Results We identified 3 potential nuclei: the centromedian (CM), ventral posterior medial (VPM), and anterior pulvinar. The best results were during VPM stimulation (>90% reduction in pain) and CM stimulation (50% reduction). Following 3 mo of VPM-DBS in combination of lateral CM stimulation, their pain disability index dropped (from 25 to 0) and short form 36 improved (from 67.5 to 90). Conclusion VPM stimulation in combination with CM stimulation is a promising target for NDP. DBS electrode directionality can be used to test multiple targets and select a patient specific "sweet spot" for NDP treatment.

Objective Laminectomy and fusion is a standard technique in patients with multilevel degenerative cervical myelopathy (DCM). However, this procedure is associated with a reduction of cervical range of motion. This study examines how patients are subjectively restricted in cervical spine mobility, how they are impaired in activities of daily living (ADLs) and how this affects their quality of life. Methods In this single-center, retrospective cohort study patients with DCM operated via laminectomy and fusion over at least four segments were included. Clinical outcome was assessed via pain scores, NDI, patient satisfaction index, mJOA and SF-8. The patient-reported restriction of cervical spine mobility and the resulting impairment for various ADLs were acquired by a newly developed five-step score. Results 53 patients could be evaluated. 75.5 % were satisfied with the treatment. 41.5 % reported a moderate restriction of mobility, followed by severe restriction in 34.0 % and mild restriction in 15.1 %. Of the various directions of movement, flexion was indicated as the least restricted. Overhead work was the most impaired activity (26.4 % severe restriction, 37.7 % complete restriction). 60.4 % experienced none to moderate impairment when driving a car. The mean values for the SF-8 were 37.5 for the physical and 47.8 for the mental component summary. Conclusion Despite multilevel fusion and the reduced physical component summary of the SF-8, more than half of the patients reported only mild to moderate restriction. The concern about a complete impairment in various ADLs is unfounded for the majority of patients.

OBJECTIVEIntraoperative 3D imaging and navigation is increasingly used for minimally invasive spine surgery. A novel, noninvasive patient tracker that is adhered as a mask on the skin for 3D navigation necessitates a larger intraoperative 3D image set for appropriate referencing. This enlarged 3D image data set can be acquired by a state-of-the-art 3D C-arm device that is equipped with a large flat-panel detector. However, the presumably associated higher radiation exposure to the patient has essentially not yet been investigated and is therefore the objective of this study.METHODSPatients were retrospectively included if a thoracolumbar 3D scan was performed intraoperatively between 2016 and 2019 using a 3D C-arm with a large 30 × 30–cm flat-panel detector (3D scan volume 4096 cm3) or a 3D C-arm with a smaller 20 × 20–cm flat-panel detector (3D scan volume 2097 cm3), and the dose area product was available for the 3D scan. Additionally, the fluoroscopy time and the number of fluoroscopic images per 3D scan, as well as the BMI of the patients, were recorded.RESULTSThe authors compared 62 intraoperative thoracolumbar 3D scans using the 3D C-arm with a large flat-panel detector and 12 3D scans using the 3D C-arm with a small flat-panel detector. Overall, the 3D C-arm with a large flat-panel detector required more fluoroscopic images per scan (mean 389.0 ± 8.4 vs 117.0 ± 4.6, p < 0.0001), leading to a significantly higher dose area product (mean 1028.6 ± 767.9 vs 457.1 ± 118.9 cGy × cm2, p = 0.0044).CONCLUSIONSThe novel, noninvasive patient tracker mask facilitates intraoperative 3D navigation while eliminating the need for an additional skin incision with detachment of the autochthonous muscles. However, the use of this patient tracker mask requires a larger intraoperative 3D image data set for accurate registration, resulting in a 2.25 times higher radiation exposure to the patient. The use of the patient tracker mask should thus be based on an individual decision, especially taking into considering the radiation exposure and extent of instrumentation.

Objective We report on our experiences of navigated posterior C1–C2 spondylodesis in the elderly (≥ 70 years of age). Patients This retrospective cohort study evaluated all patients ≥ 70 years of age treated with navigated posterior spondylodesis C1-C2 (at the most to C3) from 2008 to 2015 with a minimum follow-up of 1 year. Minor and major complications within 30 days after surgery, patient outcome, and the rate of solid fusion in computed tomography were recorded. The follow-up over 1 year was conducted by outpatient examinations and via telephone interviews. Results Twenty-two patients with a mean age of 79.9 years (range: 71–91 years) were treated. Minor complications were mild pneumonia (18.2%), postoperative confusion (9.1%), and urinary tract infection (4.5%). Major complications were severe pneumonia (4.5%) and clinically asymptomatic vertebral artery injury (4.5%). The mortality rate was 13.6% (n = 3) within the first 30 days after surgery and 22.7% (n = 5) within 1 year. All deceased patients were > 85 years of age. Conclusion In our patient population, posterior spondylodesis was shown to be beneficial for patients > 70 years up to age ∼ 85 years. The mortality rate increased sharply in patients > 85 years. In these patients the indication for surgery should be critically evaluated.

Therapeutically resected, adult brain segments were maintained and characterized for an extended period to study glioblastoma progression and treatment in its almost natural environment., When it comes to the human brain, models that closely mimic in vivo conditions are lacking. Living neuronal tissue is the closest representation of the in vivo human brain outside of a living person. Here, we present a method that can be used to maintain therapeutically resected healthy neuronal tissue for prolonged periods without any discernible changes in tissue vitality, evidenced by immunohistochemistry, genetic expression, and electrophysiology. This method was then used to assess glioblastoma (GBM) progression in its natural environment by microinjection of patient-derived tumor cells into cultured sections. The result closely resembles the pattern of de novo tumor growth and invasion, drug therapy response, and cytokine environment. Reactive transformation of astrocytes, as an example of the cellular nonmalignant tumor environment, can be accurately simulated with transcriptional differences similar to those of astrocytes isolated from acute GBM specimens. In a nutshell, we present a simple method to study GBM in its physiological environment, from which valuable insights can be gained. This technique can lead to further advancements in neuroscience, neuro-oncology, and pharmacotherapy.

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory, systemic skeletal disease. The associated formation of anterior cervical osteophytes can cause severe dysphagia, so the osteophytes have to be surgically removed. Because the clinical syndrome is rare, long-term outcome after surgical therapy is likewise scarce. In this retrospective, single-center study, five consecutive patients with DISH causing dysphagia and following resection of osteophytes between 2005 and 2015 were included. Patient and surgical reports were evaluated regarding surgery-related and postoperative complications. For the short term, the outpatient visits three months and one year after the surgery were evaluated. For the long-term results, patients were followed via questionnaires concerning actual complaints, complications or further treatment associated to DISH. Five male patients (61.6 years old; range, 43–77) were operated. One patient had a transitory worsening of a preexisting hoarseness and one patient had permanent problems with singing postoperatively. All patients reported improvement of dysphagia after three months. One patient deceased five years after surgery independently of DISH without complaining about recurring dysphagia. After a mean follow-up of 70.3 months (range, 24–126 months), dysphagia was consistently improved in all remaining four patients. The patient with the slightest improvement and clinical deterioration in the course had an initially incomplete resection of osteophytes. Imaging showed a re-increase of ossifications 2.5 years after the surgery. Resection of symptomatic anterior osteophytes in DISH is a safe and promising procedure to improve dysphagia in the long-term, but the recurrence of osteophytes is possible years after initial treatment.