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ZusammenfassungBei der idiopathischen ventralen Rückenmarksherniation handelt es sich um einen sehr seltenen Defekt der thorakalen ventralen Dura, am häufigsten zwischen BWK 2 und BWK 8, mit konsekutivem Prolaps des Myelons in diesen Duradefekt hinein. Klinisch führt dies oft nach jahrelanger Anamnese zu einer progredienten, mehr oder weniger stark ausgeprägten Myelopathie, z. B. einem Brown-Séquard Syndrom oder einer Paraparese. Die Ursache des Duradefekts und der Mechanismus der Herniation sind nicht geklärt. Diskutiert werden Bandscheibenpathologien wie verkalkte Mikrosporne, Trauma, Entzündung, eine Bindegewebsschwäche und angeborene Dura-Duplikaturen. Die wichtigsten Differentialdiagnosen sind arachnoidale Zysten und arachnoidale Netze (arachnoidal web), die das Myelon bei jedoch intakter Dura nach ventral verlagern, Tumore sowie ischämische und traumatische Myelomalazien. Trotz exzellenter Bildgebung gelingt manchmal die sichere Diagnose einer Myelonhernie samt Duradefekt letztendlich erst intraoperativ. Die operative Versorgung ist, einschließlich auch der nur leicht symptomatischen Patienten, die Therapie der Wahl und stellt eine neurochirurgische Herausforderung dar. Ziel ist das Lösen des Rückenmarks mit, je nach Größe und Lage, entweder Verschluss, Augmentation oder Erweiterung des Duradefekts. Das Risiko für postoperative Defizite beträgt 5–12%. Von einem Behandlungserfolg wird meist bei einem Stopp der klinischen Progression ausgegangen, wobei bis zu 3/4 der Patienten eine Chance auf postoperative Besserung haben. Die operative Behandlung sollte mit intraoperativem Neuromonitoring (SSEP, MEP, D-Welle) in Zentren mit entsprechender Erfahrung erfolgen. Patienten, bei denen noch keine Operationsindikation gestellt wurde, sollten engmaschig angebunden werden, da der natürliche Krankheitsverlauf der idiopathischen ventralen Rückenmarksherniation meist progredient ist.

Objective For patients with multilevel degenerative cervical myelopathy, laminectomy and fusion are widely accepted techniques for ameliorating the disorder. However, the idea of whether one should bridge the cervicothoracic junction to prevent instrument failure or adjacent segment disease has been a subject of controversial discussion. In the present study, we compared the incidence of these complications and the revision rates in multilevel fusions extending to C7 or T1–T3. Methods In the present single-center, retrospective cohort study, patients with multilevel degenerative cervical myelopathy treated with laminectomy and fusion to C7 or T1–T3 from 2004 to 2016 were included for evaluation. The primary outcome measure was radiologically proven complications at the most caudal level or the adjacent spinal fusion level. Results Laminectomy and multilevel fusion were performed in 84 patients. After applying the exclusion criteria, 20 patients with fusion to C7 (treated from 2004 to 2012; follow-up, 124.6 ± 10.6 months) and 38 patients with fusion to T1–T3 (treated from 2008 to 2016; follow-up, 58.2 ± 15.7 months) were evaluated. The incidence of complications at the most caudal or adjacent level of fusion was twice as high (P = 0.087; NS) in the C7 group (11 of 20; 55.0%) compared with the T1–T3 group (11 of 38; 28.9%). In the C7 group, 9 of the 20 patients (45.0%) had required revision surgery compared with 2 of 38 patients (5.3%) in the T1–T3 group (P = 0.001). Conclusions We found that fewer revisions were necessary if the fusion had extended to the thoracic spine. Thus, we recommend bridging the cervicothoracic junction when fusion starts at C0–C3.

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

Background and Study Objective One risk of established decompression techniques for lumbar spinal stenosis is the resection of facet joints, especially if they are steeply configured, promoting destabilization. Minimally invasive bilateral crossover decompression aims to preserve the facet joints and thus stability of the spine. The purpose of this study is to demonstrate the feasibility and early results of this technique. Methods This retrospective case series includes 10 consecutive patients with lumbar stenosis and steep-angle ( Results After a follow-up of 10.5 months, the Symptom Severity Scale and Physical Function Scale of the Swiss Spinal Stenosis Questionnaire improved by 0.9 (p Conclusion The results of this study indicate that minimally invasive bilateral crossover decompression is a promising technique for the treatment of spinal canal stenosis. With its design to spare facet joints, it can potentially reduce the risk of spinal instability, especially in patients with steep facet joints.

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.

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.

Background Technical advances in minimally invasive spine surgery have reduced blood loss, access trauma, and postoperative length of stay. However, operating on the susceptible group of octogenarians still poses a dilemma because of a plethora of age-related comorbidities. The aim of this study was to investigate the safety of minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) in octogenarians. Methods We conducted a retrospective single-center study of all patients over 80 years of age who, between March 2009 and February 2014, had undergone MIS TLIF. The primary outcome was recorded major and minor complications within 30 days of surgery. Results Twenty-one patients with an average age of 84.1 ± 2.7 years underwent MIS TLIF in 31 levels for degenerative lumbar disk disease with intolerable pain after failure of conservative treatment. Of the patients, 33.3% showed no perioperative complications. In the remaining 66.7%, 6 major complications and 24 minor complications occurred within 30 days of surgery. Two of these patients died within 30 days of surgery because of sepsis and pulmonary embolism (mortality rate 9.5%). Conclusions Our study spotlighted the susceptible group of octogenarians and evaluated the safety of MIS TLIF. The perioperative morbidity for octogenarians undergoing MIS TLIF is substantial and even higher than for patients over 65 years of age. Two thirds of patients in this subgroup suffer at least 1 complication. The 30-day mortality rate was 9.5%. Therefore, it is advisable for these patients to exploit all available conservative options prior to surgery.

Study design A retrospective subgroup analysis of a prospective observational study was carried out. Summary of background data Patients' baseline characteristics may influence the clinical outcomes after minimally invasive lumbar interbody fusion (MILIF). Objective This study aimed to investigate the influence of patient's age and body mass index (BMI) on the clinical outcomes of MILIF for degenerative lumbar disorder. Materials and methods A total of 252 patients underwent MILIF. The clinical outcomes, including time to first ambulation, time to postsurgical recovery, back/leg pain in visual analog scale, Oswestry Disability Index, and EuroQol-5 Dimension, were collected at baseline, 4 weeks, 6, and 12 months. Patients were subgrouped by age (50 y and below: N=102; 51-64 y: N=102; 65 y and above: N=48) and BMI (≤25.0: N=79; 25.1-29.9: N=104; ≥30.0: N=69). Data from baseline to 12 months were compared for all clinical outcomes within age/BMI subgroups. Adverse events (AEs) and serious adverse events (SAEs) were summarized by age and BMI subgroups. Results All age and BMI subgroups showed significant improvements in clinical outcomes at 12 months compared with the baseline. The median time to first ambulation was similar for all subgroups (age groups: P=0.8707; BMI: P=0.1013); older people show a trend of having longer time to postsurgical recovery (age groups: P=0.0662; BMI: P=0.1591). Oswestry Disability Index, back, and leg pain visual analog scale, and EuroQol-5 Dimension were similar in all subgroups at every timepoint. A total of 50 AEs (N=39) were reported, 9 of which were SAEs; 3 AEs and 1 SAE were considered to be related to surgical procedure. No differences were observed in safety by age groups and BMI groups. Conclusion MILIF appears to be safe and effective, independent of age or weight in the treatment of degenerative lumbar disorder. Level of evidence Level II.

OBJECTIVE Spinal CSF leaks cause spontaneous intracranial hypotension (SIH). Surgical closure of spinal CSF leaks is the treatment of choice for persisting leaks. Surgical approaches vary, and there are no studies in which minimally invasive techniques were used. In this study, the authors aimed to detail the safety and feasibility of minimally invasive microsurgical sealing of spinal CSF leaks using nonexpandable tubular retractors. METHODS Consecutive patients with SIH and a confirmed spinal CSF leak treated at a single institution between April 2019 and December 2020 were included in the study. Surgery was performed via a dorsal 2.5-cm skin incision using nonexpandable tubular retractors and a tailored interlaminar fenestration and, if needed, a transdural approach. The primary outcome was successful sealing of the dura, and the secondary outcome was the occurrence of complications. RESULTS Fifty-eight patients, 65.5% of whom were female (median age 46 years [IQR 36–55 years]), with 38 ventral leaks, 17 lateral leaks, and 2 CSF venous fistulas were included. In 56 (96.6%) patients, the leak could be closed, and in 2 (3.4%) patients the leak was missed because of misinterpretation of the imaging studies. One of these patients underwent successful reoperation, and the other patient decided to undergo surgery at another institution. Two other patients had to undergo reoperation because of insufficient closure and a persisting leak. The rate of permanent neurological deficit was 1.7%, the revision rate for a persisting or recurring leak was 3.4%, and the overall revision rate was 10.3%. The rate of successful sealing during the primary closure attempt was 96.6% and 3.4% patients needed a secondary attempt. Clinical short-term outcome at discharge was unchanged in 14 patients and improved in 25 patients, and 19 patients had signs of rebound intracranial hypertension. CONCLUSIONS Minimally invasive surgery with tubular retractors and a tailored interlaminar fenestration and, if needed, a transdural approach is safe and effective for the treatment of spinal CSF leaks. The authors suggest performing a minimally invasive closure of spinal CSF leaks in specialized centers.

Currently, there is uncertainty about the predictive factors for metastatic epidural spinal cord compression (MESCC) and consecutive symptomatology in tumor patients. Prognostic algorithms for identifying patients at risk for paralysis are missing. The influence of the pathologic fracture on the patient’s symptoms is widely discussed in the literature and we hypothesize that pathologic fractures contribute to spinal cord compression and are therefore predictive of severe paralysis. We tested this hypothesis in 136 patients who underwent surgery for spinal metastases. The most common primary cancers were prostate (24.3%, n = 33), breast (11.0%, n = 15), lung (10.3%, n = 14), and cancer of unknown primary (10.3%, n = 14). MESCC primarily affected the thoracic (77.2%, n = 105), followed by the lumbar (13.2%, n = 18) and cervical (9.6%, n = 13) spine. Pathologic fractures occurred in 63.2% (n = 86) of patients, mainly in osteolytic metastases. On the American spinal injury association (ASIA) impairment scale (AIS), 63.2% (n = 86) of patients exhibited AIS grade D and 36.8% (n = 50) AIS grade C-A preoperatively. The presence of a pathologic fracture alone did not predict severe paralysis (AIS C-A, p = 0.583). However, the duration of sensorimotor impairments, patient age, spinal instability neoplastic score (SINS), and the epidural spinal cord compression (ESCC) grade together predicted severe paralysis (p = 0.006) as did the ESCC grade 3 alone (p = 0.028). This is in contrast to previous studies that stated no correlation between the degree of spinal cord compression and the severity of neurologic impairments. Furthermore, the high percentage of pathologic fractures found in this study is above previously reported incidences. The risk factors identified can help to predict the development of paralysis and assist in the improvement of follow-up algorithms and the timing of therapeutic interventions.

Delayed cerebral infarction (DCI) contributes to the burden of morbidity and mortality acquired by patients with aneurysmal subarachnoid hemorrhage (SAH). Cisternal lavage may prevent DCI. Delivery of lavage therapy to the basal cisterns, however, is challenging. Here, we report a novel method for the delivery of cisternal lavage using a cisterno-ventricular catheter (CVC) inserted via the fenestrated lamina terminalis during aneurysm clipping. In two high-risk aSAH patients a CVC was inserted into the third ventricle through the fenestrated lamina terminalis during aneurysm clipping. Post-operatively, continuous cisternal lavage using Urokinase or Nimodipine was applied using an external ventricular drain (EVD) as inflow tract and the CVC as outflow tract. Neurological outcome at 6 months was assessed by modified Rankin scale. Catheter placement into the third ventricle through the fenestrated lamina terminalis was performed without complications. Application of a free-running electrolyte solution containing Urokinase or Nimodipine via the EVD and drainage via the CVC was feasible. Cisternal Nimodipine application normalized sonographic vasospasm in both cases. DCI did not occur. CVC placement for ventriculo-cisternal lavage may represent a useful method for DCI prevention. It can be considered in aSAH patients at risk for DCI if the chiasmatic region is accessed during aneurysm clipping.

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 (

Design Prospective diagnostic study. Objectives Primary imaging-based diagnosis of spinal cord tumor-suspected lesions is often challenging. The identification of the definite entity is crucial for dedicated treatment and therefore reduction of morbidity. The aim of this trial was to investigate specific quantitative signal patterns to differentiate unclear intramedullary tumor-suspected lesions based on diffusion tensor imaging (DTI). Setting Medical Center - University of Freiburg, Germany. Methods Forty patients with an unclear tumor-suspected lesion of the spinal cord prospectively underwent DTI. Primary diagnosis was determined by histological or clinical work-up or remained indeterminate with follow-up. DTI metrics (FA/ADC) were evaluated at the central lesion area, lesion margin, edema, and normal spinal cord and compared between different diagnostic groups (ependymomas, other spinal cord tumors, inflammations). Results Mean DTI metrics for all spinal cord tumors (n = 18) showed significantly reduced FA and increased ADC values compared to inflammatory lesions (n = 8) at the lesion margin (p p = 0.001) and reduced FA at the central lesion area (p n = 10) and other spinal cord tumors (n = 8), but remaining differences for both compared to the inflammation subgroup. We found significant higher ADC (p = 0.040) and a trend to decreased FA (p = 0.081) for ependymomas compared to inflammations at the edema. Conclusion Even if distinct differentiation of ependymomas from other spinal cord neoplasms was not possible based on quantitative DTI metrics, FA and ADC were feasible to separate inflammatory lesions. This may avoid unnecessary surgery in patients with unclear intramedullary tumor-suspected lesions.

OBJECTIVE A major challenge of a minimally invasive spinal approach (MIS) is maintaining freedom of maneuverability through small operative corridors. Unfortunately, during tubular resection of intradural pathologies, the durotomy and its accompanying tenting sutures offer a smaller operating window than the maximum surface of the tube’s base. The objective of this study was to evaluate if a novel double tubular technique could expand the surgical visual field during MIS resection of intradural pathologies. METHODS A total of 25 MIS resections of intradural extramedullary pathologies were included. A posterior tubular interlaminar fenestration was performed in all surgeries. A durotomy covering the whole diameter of the tubular base was the standard in all cases. After placement of two tenting sutures on each side of the durotomy and application of tension, the resulting surface of the achieved dura fenestration was measured after optical analysis of the intraoperative video. In the next step, a second tube, 2 mm thinner than and the same length as the first, was inserted telescopically into the first tube, resulting an angulated fulcrum effect on the tenting sutures. RESULTS Optical surface analysis of the dura fenestration before and after the second tubular insertion verified a significant widening of the visual field of 43.1% (mean 18.84 mm2, 95% CI 16.8–20.8, p value < 0.001). There were no ruptured tenting sutures through the increased tension. Postoperative MRIs verified complete resection of the pathologies. CONCLUSIONS Inserting a second tube telescopically during posterior minimally invasive tubular spinal intradural surgery leads to an angulated fulcrum effect on the dura tenting sutures which consequently increases the surface of the dura fenestration and induces a meaningful widening of the visual field.

Das hier vorgestellte System verbindet das neue Konzept der Peer-to-Peer-Navigation mit dem Einsatz von Augmented Reality zur Unterstutzung von bettseitig durchgefuhrten externen Ventrikeldrainagen. Das sehr kompakte und genaue Gesamtsystem beinhaltet einen Patiententracker mit integrierter Kamera, eine Augmented-Reality-Brille mit Kamera und eine Punktionsnadel bzw. einen Pointer mit zwei Trackern, mit dessen Hilfe die Anatomie des Patienten aufgenommen wird. Die exakte Position und Richtung der Punktionsnadel wird unter Zuhilfenahme der aufgenommenen Landmarken berechnet und uber die Augmented-Reality-Brille fur den Chirurgen sichtbar auf dem Patienten dargestellt. Die Methode zur Kalibrierung der statischen Transformationen zwischen Patiententracker und daran befestigter Kamera beziehungsweise zwischen den Trackern der Punktionsnadel sind fur die Genauigkeit sehr wichtig und werden hier vorgestellt. Das Gesamtsystem konnte in vitro erfolgreich getestet werden und bestatigt den Nutzen eines Peer-to-Peer-Navigationssystems.

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.

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.

Randomized controlled trial.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).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.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.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, P0.001).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.1.

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.

The tensile strength of the intervertebral disc (IVD) is mainly maintained by collagen cross-links. Loss of collagen cross-linking combined with other age-related degenerative processes contributes to tissue weakening, biomechanical failure, disc herniation and pain. Exogenous collagen cross-linking has been identified as an effective therapeutic approach for restoring IVD tensile strength. The current state-of-the-art method to assess the extent of collagen cross-linking in tissues requires destructive procedures and high-performance liquid chromatography. In this study, we investigated the utility of infrared attenuated total reflection (IR-ATR) spectroscopy as a nondestructive analytical strategy to rapidly evaluate the extent of UV-light-activated riboflavin (B2)-induced collagen cross-linking in bovine IVD samples. Thirty-five fresh bovine-tail IVD samples were equally divided into five treatment groups: (a) untreated, (b) cell culture medium Dulbecco's Modified Eagle's Medium only, (c) B2 only, (d) UV-light only and (e) UV-light-B2. A total of 674 measurements have been acquired, and were analyzed via partial least squares discriminant analysis. This classification scheme unambiguously identified individual classes with a sensitivity >91% and specificity >92%. The obtained results demonstrate that IR-ATR spectroscopy reliably differentiates between different treatment categories, and promises an excellent tool for potential in vivo, nondestructive and real-time assessment of exogenous IVD cross-linking.

Retrospective case-control study.To compare the incidence, management, and outcome of incidental durotomy in revision microdiscectomy with open and minimal-access surgery.Incidental durotomy occurs with a variable incidence of 3%-27% in spine surgery. The highest rate occurs in revision microdiscectomy. The intraoperative and postoperative management of dural tears varies in the literature and the definite impact on clinical outcome has to be clarified.This is a retrospective study of medical records of 135 patients who underwent revision microdiscectomy, divided into 2 subgroups: OPEN (n=82) versus minimal-access surgery (MINI, n=53). Occurrence of intraoperative dural tears, intraoperative and postoperative management of durotomy, and clinical outcomes, according to MacNab criteria, were retrospectively examined. Statistical comparisons for categorical values between groups were accomplished using the 2-tailed Fisher exact test. P-values0.05 were considered to be statistically significant.The incidence of durotomy in group OPEN was 19.5% (n=16/82) and in group MINI 17.0% (n=9/53) (P=0.822). The majority of durotomies (23/25) were repaired with an absorbable fibrin sealant patch alone. Postoperative cerebrospinal fluid fistula occurred only in 1 case of the OPEN group and was treated with lumbar drainage without the need for a reoperation. Patients with durotomy of the MINI group tended to have better outcome compared with those of the OPEN group without being statistically significant.The incidence of durotomy and postoperative cerebrospinal fluid fistula in lumbar revision microdiscectomy does not significantly differ between minimal-access and standard open procedures. The application of a fibrin sealant patch alone is an effective strategy for dural repair in revision lumbar microdiscectomy.

A radiation exposure study in vitro.This study aimed to compare the radiation exposure of 2 different 3-dimensional (3D) C-arm devices on an anthropomorphic phantom.Minimally invasive pedicle screw placement requires intraoperative imaging techniques for visualization of the unexposed spine. Mobile 3D C-arms compose a 3D image data set out of multiple successive fluoroscopic images.We compared the 3D C-arm devices Siremobil Iso-C 3D (Siemens Sector Healthcare, Erlangen, Germany) and Vision FD Vario 3D (Ziehm Imaging, Nuremberg, Germany) regarding their radiation exposure. For this purpose, dosimeters were attached on an anthropomorphic phantom at various sites (eye lenses, thyroid gland, female, and male gonads). With each C-arm, 10 automated 3D scans as well as 400 fluoroscopic images were performed on the cervical and lumbar spine, respectively.The Vision FD Vario 3D generally causes higher radiation exposures than the Siremobil Iso-C 3D. Significantly higher radiation exposures were assessed at the eye lenses performing cervical (294.1 vs. 84.6 μSv) and lumbar 3D scans (22.5 vs. 11.2 μSv) as well as at the thyroid gland performing cervical 3D scans (4405.2 vs. 2761.9 μSv). Moreover, the Vision FD Vario 3D caused significantly higher radiation exposure at the eye lenses for standard cervical fluoroscopic images (3.2 vs. 0.4 μSv).3D C-arms facilitate minimally invasive and accurate pedicle screw placement by providing 3D image datasets for intraoperative 3D imaging and navigation. However, the hereby potentially increased radiation exposure has to be considered. In particular, the Vision FD Vario 3D appears to generally evoke higher radiation exposures than the Siremobil Iso-C 3D. Well-indicated application of ionizing radiation and compliance with radiation protection principles remain mandatory to keep radiation exposure to patient and staff as low as reasonably achievable.

Object We report on our experience with treating juxtafacet cysts focusing on clinical outcome, rate of recurrence and secondary surgery, especially fusion. Methods This retrospective study evaluates patients who underwent surgical resection of juxtafacet cysts without concomitant fusion from 2002 to 2013 with a minimum follow-up of one year. Results Complete follow-up is available in 74 patients. Mean follow-up in all 74 patients was 69 ± 34 months (range, 14–140 months). Mean ODI was 14.9%. 68 patients (91.9%) were pleased with the results and would undergo surgery again. Three patients (4.1%) underwent secondary resection because of cyst recurrence at the same site. Four patients (5.4%) needed secondary fusion. Conclusions In patients without evident clinical and radiological criteria of instability we regard surgical resection of juxtafacet cysts without concomitant fusion as adequate primary treatment due to good outcome and low incidence of secondary symptomatic instability.

Purpose The violation of the cranial adjacent facet is a frequent complication in lumbar instrumentations and can induce local pain and adjacent segment disease. Minimally invasive screw implantation is often stated as risk factor in comparison with open approaches. Percutaneous pedicle screw placement (PPSP) can be performed using single X-ray images (fluoroscopy) or intraoperative 3D navigation. The study compares top-level screws in percutaneous lumbar instrumentations regarding facet violations and screw pedicle position using navigation or fluoroscopy. Methods Patients after lumbar PPSP were retrospectively separated according to the intraoperative technique: navigation (NAV) or fluoroscopy (FLUORO). Two blinded investigators graded the top-level screws regarding facet violations and pedicle breach in postoperative CT scans. Subsequent matched cohort analysis was performed for comparable groups. Results Evaluating 768 screws, we assessed 70 (9.1%) facet violations. Overall, 186 (24.2%) screws were implanted using navigation. There was no significant difference in the rate of facet violations between both imaging groups (NAV 19/186, 10.2%, FLUORO 51/582, 8.8%, p = 0.55). Totally, 728 (94.8%) of all screws showed a correct pedicle position. Most of the 40 unfavorable pedicle positions were placed by fluoroscopy (NAV 4/186, 2.2%, FLUORO 36/582, 6.6%, p = 0.03). The matched cohorts verified these results (facet violations: NAV 19/186, 10.2%, FLUORO 18/186, 9.7%, p = 0.55; pedicle penetrations: NAV 4/186, 2.2%, FLUORO 12/186, 6.9%, p = 0.04). Conclusions Both intraoperative imaging techniques allow lumbar PPSP with low rates of cranial facet violations if the surgeon intends to preserve facet integrity. Navigation was superior concerning accurate pedicle screw position, but could not significantly prevent facet violations.

Background: Lumbar spinal stenosis (LSS) is frequently associated with postural instability. Although several studies evaluated patients' functional impairments, underlying sensorimotor mechanisms are still poorly understood. We aimed to assess the specific set of postural control deficits associated with LSS during spontaneous and externally perturbed stance and evaluated post-surgical changes in postural behavior.Methods: We analyzed postural control in eleven LSS patients (age 69 ± 8 years) pre- and post-laminectomy, correlated experimental data with functional tests and patient-reported outcomes, and compared findings to 15 matched, healthy control subjects (age 70 ± 6 years). Postural control was characterized by spontaneous sway measures and measures of perturbed stance. Perturbations were induced by anterior-posterior pseudorandom tilts of the body support surface. We used an established postural control model to extract specific postural control parameters.Results: Spontaneous sway amplitude, velocity and frequency were abnormally large in LSS patients. Furthermore, patients' postural reactions to platform tilts, represented by GAIN and PHASE were significantly altered. Based on simple feedback model simulations, we found that patients rely less on proprioceptive cues for stance regulation than healthy subjects. Moreover, their postural reactions' timing is altered. After surgery, patients' spontaneous sway amplitude was significantly reduced and their postural timing approximated the behavior of healthy subjects.Conclusion: The reduction in proprioceptive input for stance control due to stenosis-caused afferent dysfunction is a functional disadvantage for LSS patients – and may be the basis of increased spontaneous sway. This disadvantage may cause the timing of postural reactions to alter, with the intent of preventing rapid changes in stance regulation for safety reasons. After surgery, patients' postural timing approximated those of healthy subjects, while the abnormally low use of proprioception remained unchanged. We suggest the post-surgery rehabilitation of proprioception, eg through balance exercises on unstable surfaces and reduced visual input.

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.

Safe treatment of giant central thoracic disc herniations (cTDHs) remains a surgical challenge due to frequent calcifications, intradural extension and, importantly, the rare exposure of spine surgeons to these lesions. We report our 10-year experience in the management of giant cTDH by mini-thoracotomy and offer a detailed description of the technique. 17 patients harboring 17 giant cTDH operated on via a mini-thoracotomy at the authors’ institution between 2004 and 2014 were reviewed. All patients presented with myelopathy of varying magnitude. Mean patient age was 47 years. The mean follow-up period was 5.5 years. Median canal compromise of the cTDH was 66 %. cTDH were densely calcified in 7 (41 %), partially calcified in 6 (35 %) and soft in 4 (24 %) patients. Intradural extension of cTDH was noted in six patients (35 %). Benzels’ modified myelopathy score of the Japanese Orthopedic Association was adjusted for the evaluation of thoracic myelopathy (mJOA) to assess functional outcomes. Successful removal of the offending cTDH was achieved in all patients. The overall mJOA Score improved from 7.9/13 to 11.1/13. Two patients with giant and densely calcified cTDH experienced a transient post-operative neurological decline. There was a statistically significant correlation between size of cTDH and intradural extension. Patients with myelopathy due to giant cTDH can be safely treated by the mini-thoracotomy approach. Postoperative neurological worsening and severe complications or incisional pain are rare. In contrast to complex posterior or thoracoscopic approaches, the mini-thoracotomy is technically straightforward and thus easy to learn for experienced spine surgeons.

OBJECT The aim of the study was to investigate the safety and efficacy of minimally invasive tubular microdiscectomy for the treatment of recurrent lumbar disc herniation (LDH). As opposed to endoscopic techniques, namely microendoscopic and endoscopic transforaminal discectomy, this microscopically assisted technique has never been used for the treatment of recurrent LDH. METHODS Thirty consecutive patients who underwent minimally invasive tubular microdiscectomy for recurrent LDH were included in the study. The preoperative and postoperative visual analog scale (VAS) scores for pain, the clinical outcome according to modified Macnab criteria, and complications were analyzed retrospectively. The minimum follow-up was 1.5 years. Student t-test with paired samples was used for the statistical comparison of pre- and postoperative VAS scores. A p value < 0.05 was considered to be statistically significant. RESULTS The mean operating time was 90 ± 35 minutes. The VAS score for leg pain was significantly reduced from 5.9 ± 2.1 preoperatively to 1.7 ± 1.3 postoperatively (p < 0.001). The overall success rate (excellent or good outcome according to Macnab criteria) was 90%. Incidental durotomy occurred in 5 patients (16.7%) without neurological consequences, CSF fistula, or negative influence to the clinical outcome. Instability occurred in 2 patients (6.7%). CONCLUSIONS The clinical outcome of minimally invasive tubular microdiscectomy is comparable to the reported success rates of other minimally invasive techniques. The dural tear rate is not associated to higher morbidity or worse outcome. The technique is an equally effective and safe treatment option for recurrent LDH.

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.We retrospectively reviewed medical records for all adult patients with a body mass index (BMI) ≥40 kg/mWe identified 14 patients with a BMI ≥ 40 kg/mMIS 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 (30 days); however, available long-term follow-up data suggest a higher complication rate, greater need for analgesics and a much lower reduction of lower back pain in the morbidly obese group.

Malignant meningiomas are a rare but aggressive subset of intracranial meningiomas leading to a very limited life expectancy. The occurrence of spinal metastases in these tumors is an even rarer event. The described patient had an intracranial malignant meningioma and developed a symptomatic osteolytic contrast-enhancing lesion in the left C-1 lateral mass suspicious for metastasis. The authors performed a minimally invasive posterior resection of the lesion with vertebroplasty of C-1. Histopathology verified metastasis of the malignant meningioma. The surgical procedure resulted in prompt and permanent pain reduction until the patient died 18 months later. Given the very limited life expectancy in this case, the authors did not consider occipitocervical fusion because of their desire to preserve the range of motion of the head. Therefore, they suggest minimally invasive tumor resection and vertebroplasty in selected palliative tumor patients.

The purpose of this systematic review is to investigate which minimally invasive techniques have been used for discectomy in recurrent lumbar disc herniation (LDH), to present the success and complication rates and to evaluate the advantages and limitations of each technique. Discectomy for recurrent LDH is accompanied by a higher morbidity rate compared with primary LDH. Because of the limited operating field, the majority of surgeons have been discouraged from utilising a minimally invasive approach for revision surgery. Minimally invasive techniques have gained ground in the treatment of primary LDH and an increasing number of patients are expressing interest in such techniques for the treatment of recurrent LDH. Microendoscopic discectomy (MED), endoscopic transforaminal and interlaminar discectomy (ETD and EID) have been used for treatment of recurrent LDH. The reported success rate is 60-95%. Full endoscopic techniques, especially ETD, showed favourable results concerning dural tear rates but have a demanding learning curve. The limitations of ETD include dislocated disc fragments or concomitant lateral recess stenosis, and MED is more effective in these instances. All three techniques have a low delayed instability rate. MED, ETD and EID are safe and efficient treatment options for surgical management of recurrent LDH with good success and low complication rates. At the same time, they offer the advantages of minimally invasive access.

Purpose. To describe the minimally invasive technique for cement augmentation of cannulated and fenestrated screws using an injection cannula as well as to report its safety and efficacy.Methods. A total of 157 cannulated and fenestrated pedicle screws had been cement-augmented during minimally invasive posterior screw-rod spondylodesis in 35 patients from January to December 2012. Retrospective evaluation of cement extravasation and screw loosening was carried out in postoperative plain radiographs and thin-sliced triplanar computed tomography scans.Results. Twenty-seven, largely prevertebral cement extravasations were detected in 157 screws (17.2%). None of the cement extravasations was causing a clinical sequela like a new neurological deficit. One screw loosening was noted (0.6%) after a mean follow-up of 12.8 months. We observed no cementation-associated complication like pulmonary embolism or hemodynamic insufficiency.Conclusions. The presented minimally invasive cement augmentation technique using an injection cannula facilitates convenient and safe cement delivery through polyaxial cannulated and fenestrated screws during minimally invasive screw-rod spondylodesis. Nevertheless, the optimal injection technique and design of fenestrated screws have yet to be identified. This trial is registered with German Clinical TrialsDRKS00006726.

Study design This was a retrospective analysis. Objective This study compares 2 different 3-dimensional (3D) C-arm devices for intraoperative imaging and navigation with regard to clinical applicability and image quality. Summary of background data Minimally invasive spine surgery requires intraoperative imaging techniques to adequately visualize the unexposed spine. For this purpose, mobile 3D C-arms became available along with the evolution of intraoperative navigation techniques. Methods The C-arm devices Siremobil Iso-C 3D (Siemens) and Vision FD Vario 3D (Ziehm) perform an automated orbital rotation around the patient acquiring a 3D image set out of multiple successive fluoroscopic images. We report on technical specifications of the C-arms and our daily experience regarding clinical applicability. Furthermore, 5 spine surgeons evaluated blinded triplanar planes of 40 cervical, thoracic, and lumbar 3D scans that were obtained during routine surgery regarding usability for navigation. We assessed the delineation of cortical bone, artifacts, and overall image quality using a 0-10 numeric rating scale. Results The Siremobil Iso-C 3D requires 128 seconds for its 190-degree scanning arc with equidistant isocenter. The Vision FD Vario 3D performs an elliptical scanning arc and completes its 135-degree scan in 64 seconds; furthermore, it features a flat panel detector and fully digital imaging. The smaller dimensions of the Vision FD Vario 3D made it easier to maneuver in the operating room compared with the more bulky Siremobil Iso-C 3D. With respect to image quality in cervical 3D scans, the Siremobil Iso-C 3D reached significantly higher scores in all categories. The Vision FD Vario 3D revealed less artifacts in lumbar 3D scans. Conclusions The Siremobil Iso-C 3D provides high-quality 3D scans in slender spine regions (eg, cervical spine), whereas the Vision FD Vario 3D appears to have advantages in the lumbar spine. Further evolution and novel devices are needed to optimize image quality and handling.

Study design Retrospective cohort study. Objective Assessment of outcome after minimally invasive posterior cervical foraminotomy (MI-PCF). Summary of background data Surgical management of cervical radiculopathy represents a controversial area in spinal surgery. Preferred approaches include both anterior cervical discectomy and posterior cervical foraminotomy (PCF). Numerous studies showed comparable results. Employing PCF eliminates risks associated with anterior approach. PCF as originally described by Spurling and Scoville necessitates extensive stripping of cervical muscles to expose the cervical spine, resulting in muscle injury, impaired muscle function, prolonged postoperative neck pain, and increased use of narcotics. There are only few studies investigating outcome after employing MI-PCF. Materials and methods Retrospective review of 34 patients who underwent MI-PCF for presenting complaints, postoperative and follow-up outcome. Results In the last follow-up the weakness resolved completely in 62.6% of patients, in 4.1% improved and in 16.5% remained unchanged. In the last follow-up 76.7% of patients originally presenting with pain reported complete resolution of pain and 10% reported partial improvement of pain. In total, 23.5% of patients were lost during follow-up as far as pain was concerned. In the last follow-up, 75% of patients achieved relative neck-pain-freedom (Visual Analog Scale≤3) at rest and 62.5% of patients under strain. The mean neck pain on Visual Analog Scale at rest was 2.13 (SD=2.42) and 3.34 (SD=3.01) under strain. In total, 93.8% (n=15) of patients would undergo the same procedure for the same achieved result. Conclusions Minimally invasive cervical foraminotomy is an effective procedure for decompression of cervical nerve roots regardless the type of the stenosis. Even employing minimally invasive technique still causes neck pain in the long term affecting up to 25% of patients. More randomized control studies are required to clarify the benefits of minimally invasive PCF.

Purpose. To compare radiographic and clinical outcomes after anterior cervical discectomy in patients with cervical degenerative disc disease using PEEK cages or PMMA spacers with a minimum 1-year follow-up.Methods. Anterior cervical discectomy was performed in 107 patients in one or two levels using empty PEEK cages (51 levels), Sulcem PMMA spacers (49 levels) or Palacos PMMA spacers (41 levels) between January, 2005 and February, 2009. Bony fusion, subsidence, and sagittal alignment were retrospectively assessed in CT scans and radiographs at follow-up. Clinical outcome was measured using the VAS, NDI, and SF-36.Results. Bony fusion was assessed in 65% (PEEK cage), 57% (Sulcem), and 46% (Palacos) after a mean follow-up of 2.5 years. Mean subsidence was 2.3–2.6 mm without significant differences between the groups. The most pronounced loss of lordosis was found in PEEK cages (−4.1°). VAS was 3.1 (PEEK cage), 3.6 (Sulcem), and 2.7 (Palacos) without significant differences. Functional outcome in the PEEK cage and Palacos group was superior to the Sulcem group.Conclusions. The substitute groups showed differing fusion rates. Clinical outcome, however, appears to be generally not correlated with fusion status or subsidence. We could not specify a superior disc substitute for anterior cervical discectomy. This trial is registered withDRKS00003591.

Object In single patients with a cerebral aneurysm an external ventricular drain (EVD), an intracranial pressure (ICP) gauge or a combined EVD and ICP gauge placement is necessary after coil embolization and initiation of postprocedural anticoagulation. The aim of this study was to examine the hemorrhage rates of drain placement within 48 h after aneurysm coiling and under anticoagulation or antiplatelet therapy. Methods We retrospectively analyzed hemorrhage rates of EVD, ICP gauge or combined EVD and ICP gauge placement in 27 patients within 48 h after coil embolization under different anticoagulation or antiplatelet schemes (heparin, acetylsalicylic acid, clopidogrel). In patients with continuous heparin via perfusor the application was stopped periprocedurally. The results were compared to literature. Results Four hemorrhages (14.8%) were observed. Three hemorrhages were petechial and one was by definition a larger hemorrhage with 8 mm × 10 mm in diameter. Conclusions EVD, ICP gauge or combined EVD and ICP gauge placements within 48 h after cerebral aneurysm coiling and under different anticoagulation or antiplatelet regimens seem to have no increased risk of hemorrhages compared to literature.

To evaluate the effectiveness and safety of percutaneous vesselplasty in pathological vertebral fractures of the thoracolumbar spine in selected tumor patients.Eleven pathological vertebral fractures in nine patients were treated with vesselplasty (Vessel-X®, MAXXSPINE). Nine of eleven vertebras (81.8 %) had major posterior wall deficiency (30 %). Clinical and radiological (CT) measures were obtained before and 3 months after the procedure.The mean VAS improved significantly from preoperative to postoperative (6.9 ± 2.2 to 3.7 ± 2.3; p0.05), as did the ODI (59.7 %± 19.2 % to 40.3 %± 24.0 %; p0.05). The physical component summary of the SF-36 was significantly improved by the operation (19.2 ± 8.0 to 31.0 ± 16.5; p0.05). Symptomatic cement leakage or other operation-associated complications were not observed. Three patients were primarily treated with concomitant minimally invasive stabilization via fixateur interne. One patient had to undergo minimally invasive stabilization via fixateur interne 4 months after vesselplasty due to further collapse of the treated vertebral body.From these preliminary results, vesselplasty appears to be a treatment option worth considering in pathological vertebral fractures, even in the case of posterior wall deficiency. Selected tumor patients might benefit from vesselplasty as a minimally invasive procedure for stabilization of the fractured vertebra, pain control, and improvement in body function and quality of life. Long-term prospective studies with a larger sample size are required to validate these results.

The authors report a very rare cause of low-back pain and sciatica in a patient with iliac vein thrombosis attributed to absence of the infrarenal segment of the inferior vena cava (IVC) with massively dilated venous collaterals draining via a paraspinal plexus into the azygous system. This 21-year-old man presented with acute low-back pain radiating to the left ventral thigh. The initial CT scan revealed an intraspinal lesion that mimicked lumbar disc herniation. Further clarification revealed an iliac vein thrombosis, which was triggered by the absence of the infrarenal segment of the IVC, a very rare vascular anomaly. Collateral venous return was developed and led to lumbar varicosities and epidural vein engorgements. Laboratory examinations revealed factor V mutation as a predisposing factor for thrombosis. The patient's symptoms were relieved with anticoagulation and antiinflammatory therapy. Absence of the infrarenal IVC associated with iliac vein thrombosis should be regarded as a very rare cause of radicular and low-back pain, and this condition can mimic the clinical and radiological signs of lumbar disc herniation. Sciatica might be the first clinical manifestation of this rare venous anomaly.

Most adult patients with pyogenic lumbar or thoracic spondylodiscitis are treated with an external orthosis and antimicrobial therapy for several weeks to months. If surgical intervention is required, a combined anterior and posterior approach for debridement and fusion with autologous bone graft or titanium mesh cage is usually performed. We here report on our experience with the use of a minimally invasive percutaneous dorsal pedicle screw-rod spondylodesis in adult patients with pyogenic lumbar or thoracic spondylodiscitis. Eight patients with lumbar, one with thoracolumbar and three with thoracic pyogenic spondylodiscitis with a mean back pain of 9/10 on the visual analog scale (VAS) and without corresponding neurological deficits were treated. Immediately after the operation, we calculated a significant reduction of the back pain on the VAS to 1.7, of leukocyte counts and C-reactive protein levels. After a mean of 61 days of continuous antimicrobial therapy during full mobilization, all patients were pain free, and leukocyte counts as well as C-reactive protein levels were normalized. We conclude that minimally invasive percutaneous fixation is a feasible and effective technique to achieve immediate pain release, avoid long-term immobilization and overcome the disadvantages of a dorsoventral procedure. However, surgical complications and possible follow-up procedures supplement the patients' risks of adverse reactions of the disease.

We report our preliminary experience with a minimally invasive image guided percutaneous trans-pedicular fixation technique of the thoracic spine in patients with significant co-morbidity. This study aims to demonstrate the feasibility and efficacy of the presented operative technique as well as to detect potential drawbacks.A navigated percutaneous application of trans-pedicular screws was performed in 14 patients with radiological validated instability of the thoracic spine and significant medical co-morbidity. Due to poor bone quality, vertebroplasty of the affected levels had to be performed in nine patients. The levels involved were (T9-12) in ten patients, the middle (T5-8) in two patients and the upper thoracic (T1-4) segments in two others. VAS scores for local back pain were used to assess clinical outcome.A total of 56 screws were inserted. There was no additional morbidity associated with the procedure. Post-operative CT scans and plain X-rays were obtained in all patients. In 2 (3.5%) medial penetration of the pedicle border occurred without neurological sequelae for the patient. Reduction of VAS scores regarding back pain during the first post-operative week was noted. Follow up ranged between 6 months and 12 months.Navigated percutaneous trans-pedicular fixation of the thoracic spine is feasible and can be performed safely in patients where open surgery is of significant risk. Pre-operative planning is essential in order to avoid intra-operative complications with the instrumentation system.

Object Synovial cysts are generally located in the lumbar spine adjacent to facet joints. Most studies recommend surgical resection. Adhesions of the lumbar synovial cyst to the dura are common and can result in dural tears with subsequent CSF fistula or nerve injury. The recurrence rate after incomplete resection of lumbar synovial cysts is unclear. For this purpose, we report on our experience of 148 patients who underwent synovial cyst resection from 2000 to 2011. Methods We reviewed records of patients who underwent microsurgical resection of symptomatic lumbar synovial cysts between 2000 and 2011 with a minimum one-year follow-up to identify cases with incomplete synovial cyst resection. Patient and surgical reports were retrospectively evaluated regarding extent of cyst resection, dural tears and surgery-related complications. Patients were asked to complete questionnaires regarding their clinical outcome and to report on further lumbar operations. Results We identified 148 patients with lumbar synovial cysts who were surgically treated in our department. In 8 patients (5.4%), the synovial cysts were not resected completely due to dural adhesions and high risk for dural tears. Sufficient decompression was achieved in all patients. Seven of these patients were pleased with the results of the operation and would undergo surgery again. The remaining patient suffered from a facet joint syndrome, which was successfully treated conservatively, without evidence of a recurrent synovial cyst in the MRI. Conclusions Only in case of severe adhesions to the dura complete resection was not enforced to avoid dural tears. In none of the 8 patients symptomatic recurrence of synovial cysts occurred. Aware of the limited numbers, we suggest rather leaving remnants of an attached synovial cyst behind after a sufficient decompression than risking dural tears and surgery-related complications. This trial is registered with DRKS00006133.

The autoinhibitory control of electrically evoked release of [ 3 H]-dopamine and the properties of that induced by nicotinic receptor (nAChR) stimulation were studied in slices of the human neocortex. In both models [ 3 H]-dopamine release was action potential-induced and exocytotic. The selective dopamine D 2 receptor agonist (−)-quinpirole reduced electrically evoked release of [ 3 H]-dopamine, yielding IC 50 and I max values of 23 nM and 76%, respectively. Also, the effects of several other subtype-selective dopamine receptor ligands confirmed that the terminal dopamine autoreceptor belongs to the D 2 subtype. The autoinhibitory feedback control was slightly operative under stimulation conditions of 90 pulses and 3 Hz, with a biophase concentration of endogenous dopamine of 3.6 nM, and was enhanced under blockade of dopamine reuptake. [ 3 H]-dopamine release evoked in an identical manner in mouse neocortical slices was not inhibited by (−)-quinpirole, suggesting the absence of dopamine autoreceptors in this tissue and underlining an important species difference. Also, nAChR stimulation-induced release of [ 3 H]-dopamine revealed a species difference: [ 3 H]-dopamine release was evoked in human, but not in rat neocortical slices. The nAChRs inducing [ 3 H]-dopamine release most probably belong to the α 3 /β 2 -subtype, according to the potencies and efficacies of subtype-selective nAChR ligands. Part of these receptors may be located on glutamatergic neurons.

OBJECTIVE: Hemangioblastomas are histologically benign lesions that occur sporadically or as a manifestation of von Hippel-Lindau disease (VHL). The treatment strategy of these neoplasms is complicated by their unpredictable growth patterns and the often irreversible neurological deficits they may cause. This study aims to outline the neurosurgical treatment options and to address the ongoing debate of surgical timing in pediatric patients with VHL. PATIENTS AND METHODS: Thirteen consecutive pediatric patients (mean age 15.1 years) who were surgically treated for intracranial (n=8) or spinal hemangioblastomas (n=5) were included in this study (range of clinical follow up 12-86 months). Ten patients were affected by von Hippel-Lindau and three were with sporadic tumors. Serial examinations, preoperative MRI studies, and operative findings were reviewed. RESULTS: Patients with cerebellar and intramedullary hemangioblastomas did not develop additional neurological deficits postoperatively. Two patients with brainstem tumors exhibited transient hemiparesis and caudal nerve palsy, respectively. Both patients recovered completely from their postoperative deficits. Preoperatively symptomatic patients with spinal tumors did not deteriorate nor improve after surgery. During the observed follow-up periods, no tumor recurrences were observed. CONCLUSION: Central nervous system (CNS) hemangioblastomas in pediatric patients can be surgically treated with low morbidity. Based on our experience, we recommend considering also the surgical removal of asymptomatic hemangioblastomas with proven radiological progression to prevent the development of permanent neurological deficits. Molecular screening of every pediatric patient and family is mandatory to enable the detection of extraneurological tumors and the development of an efficient therapeutic strategy.

Despite major advances in endovascular embolization techniques, microsurgical resection remains a reliable and effective treatment modality for dural arteriovenous fistulas (DAVF). However, intraoperative detection of these lesions and identification of feeding arteries and draining veins can be challenging. In a series of 6 patients who were not candidates for definitive treatment by endovascular embolization we evaluated the benefits and limitations of computer-assisted image guidance for surgical ablation of DAVF.Of the 6 patients, 5 presented with haemorrhage and one with seizures. Diagnosis of DAVF was made by conventional angiography and dynamic contrast enhanced MR angiography (CE-MRA). All patients were surgically treated with the assistance of a 3D high resolution T1-weighted MR data set and time-of-flight MR angiography (MRA) obtained for neuronavigation. Registration was based on cranial fiducials and image-guided surgery was performed with the navigation system.Four of the 6 patients suffered from DAVF draining into the superior sagittal sinus, one fistula drained into paracavernous veins adjacent to the superior petrosal sinus and one patient had a pial fistula draining in the straight sinus. DAVF diagnosed with conventional angiography could be located on CE-MRA and MRA prior to surgery. MRI and MRA images were combined on the neuronavigation workstation and DAVF were located intraoperatively by using a tracking device. In 4 out of 6 cases neuronavigation was used for direct intraoperative identification of DAVF. Brain shift prevented direct tracking of pathological vessels in the other 2 cases, where navigation could only be used to assist craniotomy. Microsurgical dissection and coagulation of the fistulas led to complete cure in all patients as confirmed by angiography.Neuronavigation may be used as an additional tool for microsurgical treatment of DAVF. However, in this small series of 6 cases, surgical procedures have not been substantially altered by the use of the neuronavigation system. Image guidance has been beneficial for the location of small, superficially located DAVF, whereas a navigated approach to deep-seated lesions was less accurate due to the familiar problem of brain shift and brain retraction during surgery.