Einfluss von IL-1β, TNF-α und PDGF-BB auf die Expression, Proteinkonzentration und proteolytische Aktivität der Matrixmetalloproteinase-2 in kurz-passagierten synovialen Fibroblasten von Patienten mit Gelenktrauma und rheumatoider Arthritis

Die vorliegende Arbeit untersucht den Einfluss von IL-1β, TNF-α und PDGF-BB auf die Expression, Proteinkonzentration und proteolytische Aktivität der Matrixmetalloproteinase-2 (MMP-2) in kurz-passagierten synovialen Fibroblasten (SFB) von Patienten mit Gelenktrauma (GT) und rheumatoider Arthritis (RA). Die vorliegenden Ergebnisse unterstützen die posttranslationale Regulation der MMP-2, weil IL-1β, TNF-α und PDGF-BB keinen Einfluss auf die MMP-2-mRNA-Expression, proMMP-2-Konzentration und Gesamt-MMP-2-Aktivität bei GT- und RA-SFB zeigten. Die Aktivität der frei vorliegenden, prozessierten MMP-2 wurde bei GT-SFB durch IL-1β, TNF-α und PDGF-BB signifikant vermindert, bei RA-SFB allerdings nur durch PDGF-BB. Diese Teilresistenz der RA-SFB gegenüber der „gewebsprotektiven“ Wirkung von IL-1β und TNF-α sowie die „gewebsprotektive“ Wirkung von PDGF-BB auf GT-SFB und auch RA-SFB führen zu einer vollkommen neuen Betrachtungsweise bezüglich der Rolle dieser Zytokine in der RA. Somit liefert diese Arbeit auch neue Aspekte der MMP-2 als hochpotente matrixdegradierende Proteinase in der Pathogenese und der Gelenkdestruktion in der RA

Radiation exposure of a mobile 3D C-arm with large flat-panel detector for intraoperative imaging and navigation - an experimental study using an anthropomorphic Alderson phantom

Background!#!Intraoperative 3-dimensional (3D) navigation is increasingly being used for pedicle screw placement. For this purpose, dedicated mobile 3D C-arms are capable of providing intraoperative fluoroscopy-based 3D image data sets. Modern 3D C-arms have a large field of view, which suggests a higher radiation exposure. In this experimental study we therefore investigate the radiation exposure of a new mobile 3D C-arm with large flat-panel detector to a previously reported device with regular flat-panel detector on an Alderson phantom.!##!Methods!#!We measured the radiation exposure of the Vision RFD 3D (large 30 × 30 cm detector) while creating 3D image sets as well as standard fluoroscopic images of the cervical and lumbar spine using an Alderson phantom. The dosemeter readings were then compared with the radiation exposure of the previous model Vision FD Vario 3D (smaller 20 × 20 cm detector), which had been examined identically in advance and published elsewhere.!##!Results!#!The larger 3D C-arm induced lower radiation exposures at all dosemeter sites in cervical 3D scans as well as at the sites of eye lenses and thyroid gland in lumbar 3D scans. At ​​male and especially female gonads in lumbar 3D scans, however, the larger 3D C-arm showed higher radiation exposures compared with the smaller 3D C-arm. In lumbar fluoroscopic images, the dosemeters near/in the radiation field measured a higher radiation exposure using the larger 3D C-arm.!##!Conclusions!#!The larger 3D C-arm offers the possibility to reduce radiation exposures for specific applications despite its larger flat-panel detector with a larger field of view. However, due to the considerably higher radiation exposure of the larger 3D C-arm during lumbar 3D scans, the smaller 3D C-arm is to be recommended for short-distance instrumentations (mono- and bilevel) from a radiation protection point of view. The larger 3D C-arm with its enlarged 3D image set might be used for long instrumentations of the lumbar spine. From a radiation protection perspective, the use of the respective 3D C-arm should be based on the presented data and the respective application

Idiopathische ventrale Rückenmarksherniation

Idiopathic spinal cord herniation is a very rare defect of the thoracic ventral dura, most often between Th 2 and Th 8, with consecutive herniation of the spinal cord into this defect. After a long history, sometimes years, clinical signs and symptoms of a progressive, more or less severe myelopathy ensue, leading to a Brown-Sequard syndrome or parapareses as typical manifestations. Neither cause nor mechanism of the herniation are fully understood, yet. Amongst others, disc disease, like calcified microspurs, trauma, inflammation, connective tissue disorder and inherited duplication of the dura are considered. The most relevant differential diagnoses are arachnoid cysts and arachnoidal webs, that may push the spinal cord ventrally but leave the dura intact, as well as tumors, ischemic and traumatic spinal cord lesions. Despite excellent imaging possibilities sometimes it happens that the actual diagnosis of a spinal cord herniation with an underlying dural defect can only be made during microsurgery. Surgery, also for only mildly symptomatic patients, is challenging but the procedure of choice. The surgical goal is to release the spinal cord and then, depending on its size and location, either to close, augment, or widen the underlying dural defect. The risk for postoperative new deficits is 5-12%. The halt of the clinical progression is considered a treatment success, with ¾ of patients having the chance of postoperative improvement. Surgery should be performed with intraoperative neuromonitoring (SSEP, MEP, D-wave) in experienced centers. Patients in whom the indication for surgery has not yet been made should be closely monitored, because most likely the natural history of idiopathic ventral spinal cord herniation is progressive

Accidental Durotomy in Minimally Invasive Transforaminal Lumbar Interbody Fusion: Frequency, Risk Factors, and Management

Purpose. To assess the frequency, risk factors, and management of accidental durotomy in minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Methods. This single-center study retrospectively investigates 372 patients who underwent MIS TLIF and were mobilized within 24 hours after surgery. The frequency of accidental durotomies, intraoperative closure technique, body mass index, and history of previous surgery was recorded. Results. We identified 32 accidental durotomies in 514 MIS TLIF levels (6.2%). Analysis showed a statistically significant relation of accidental durotomies to overweight patients (body mass index ≥25 kg/m2; P=0.0493). Patient age older than 65 years tended to be a positive predictor for accidental durotomies (P=0.0657). Mobilizing patients on the first postoperative day, we observed no durotomy-associated complications. Conclusions. The frequency of accidental durotomies in MIS TLIF is low, with overweight being a risk factor for accidental durotomies. The minimally invasive approach seems to minimize durotomy-associated complications (CSF leakage, pseudomeningocele) because of the limited dead space in the soft tissue. Patients with accidental durotomy can usually be mobilized within 24 hours after MIS TLIF without increased risk. The minimally invasive TLIF technique might thus be beneficial in the prevention of postoperative immobilization-associated complications such as venous thromboembolism. This trial is registered with DRKS00006135

Minimally Invasive Technique for PMMA Augmentation of Fenestrated Screws

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 Trials DRKS00006726

PEEK Cages versus PMMA Spacers in Anterior Cervical Discectomy: Comparison of Fusion, Subsidence, Sagittal Alignment, and Clinical Outcome with a Minimum 1-Year Follow-Up

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 with DRKS00003591

Spinal Cord Motion in Degenerative Cervical Myelopathy: The Level of the Stenotic Segment and Gender Cause Altered Pathodynamics

In degenerative cervical myelopathy (DCM), focally increased spinal cord motion has been observed for C5/C6, but whether stenoses at other cervical segments lead to similar pathodynamics and how severity of stenosis, age, and gender affect them is still unclear. We report a prospective matched-pair controlled trial on 65 DCM patients. A high-resolution 3D T2 sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) and a phase-contrast magnetic resonance imaging (MRI) sequence were performed and automatically segmented. Anatomical and spinal cord motion data were assessed per segment from C2/C3 to C7/T1. Spinal cord motion was focally increased at a level of stenosis among patients with stenosis at C4/C5 (n = 14), C5/C6 (n = 33), and C6/C7 (n = 10) (p < 0.033). Patients with stenosis at C2/C3 (n = 2) and C3/C4 (n = 6) presented a similar pattern, not reaching significance. Gender was a significant predictor of higher spinal cord dynamics among men with stenosis at C5/C6 (p = 0.048) and C6/C7 (p = 0.033). Age and severity of stenosis did not relate to spinal cord motion. Thus, the data demonstrates focally increased spinal cord motion depending on the specific level of stenosis. Gender-related effects lead to dynamic alterations among men with stenosis at C5/C6 and C6/C7. The missing relation of motion to severity of stenosis underlines a possible additive diagnostic value of spinal cord motion analysis in DCM