Jan-Helge Klingler

Rupture of a spinal artery aneurysm attributable to exacerbated Sjögren syndrome: case report.

OBJECTIVEPresentation of a patient with acute subarachnoid hemorrhage from a ruptured spinal artery aneurysm attributable to exacerbated Sjögren syndrome. CLINICAL PRESENTATIONA 46-year-old woman with symptoms of exacerbated Sjögren syndrome experienced the acute onset of extreme headache accompanied by nuchal rigidity. INTERVENTIONA computed tomographic scan revealed subarachnoid hemorrhage. Angiography showed an isolated aneurysm of a branch of the right vertebral artery that was a feeding artery of the anterior spinal artery. Neither operative clipping nor endovascular coiling of the aneurysm was reasonable, owing to the high risk of occluding the anterior spinal artery during the intervention. Further diagnostic measures confirmed Sjögren syndrome and revealed cryoglobulinemic vasculitis, membranoproliferative glomerulonephritis with acute renal failure, Hashimoto thyroiditis, and acute hydrocephalus. In the course of conservative treatment, the patient recovered completely from the subarachnoid hemorrhage. One year after treatment with glucocorticoids and immunosuppressive agents, both the aneurysm and the vasculitis could no longer be detected on conventional angiography. CONCLUSIONGenerally, spinal artery aneurysms are exceptionally rare, and few cases of rupture with subsequent subarachnoid hemorrhage have been published. We report on a ruptured spinal aneurysm attributable to Sjögren syndrome–associated cryoglobulinemic vasculitis. Conservative treatment with glucocorticoids and immunosuppressive agents led to resolution of the vasculitic spinal aneurysm.

Comparative Study of C-Arms for Intraoperative 3-Dimensional Imaging and Navigation in Minimally Invasive Spine Surgery Part II - Radiation Exposure.

Study Design: A radiation exposure study in vitro. Objective: This study aimed to compare the radiation exposure of 2 different 3-dimensional (3D) C-arm devices on an anthropomorphic phantom. Summary of Background Data: 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. Methods: 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. Results: 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 &mgr;Sv) and lumbar 3D scans (22.5 vs. 11.2 &mgr;Sv) as well as at the thyroid gland performing cervical 3D scans (4405.2 vs. 2761.9 &mgr;Sv). 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 &mgr;Sv). Conclusions: 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.

Essentials and pitfalls in the treatment of CNS hemangioblastomas and von Hippel-Lindau disease.

Hemangioblastomas are rare CNS tumors, which are mostly located in the posterior fossa or spinal cord and occasionally in spinal nerves. They can occur sporadically or as a component tumor of von Hippel-Lindau (VHL) disease, an autosomal dominant tumor syndrome. The limited awareness of several pitfalls in the therapy of these rare lesions results in delayed or suboptimal treatment for many of these patients, especially those with VHL disease. The University of Freiburg serves as a reference center for patients with VHL disease and hemangioblastomas. The current therapeutic strategies for hemangioblastoma patients and typical pitfalls are presented here.

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.

Associations of Collagen Type I α2 Polymorphisms with the Presence of Intracranial Aneurysms in Patients from Germany

OBJECTIVE Subarachnoid hemorrhage from ruptured intracranial aneurysms is associated with a severe prognosis. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the identification of risk patients by genetic analyses is not possible because of lack of candidate genes. Collagen type I α2 (COL1A2) has been associated with the presence of aneurysms in patients from Japan, China, and Korea. In this study, we investigate whether COL1A2 is a possible aneurysm candidate gene in the German population. METHODS Patients admitted with intracranial aneurysms to our department and collaborating departments were enrolled. Three single-nucleotide polymorphisms (SNPs) of the COL1A2 gene, namely rs42524 in exon 28, rs1800238 in exon 32, and rs2621215 in intron 46 were investigated using restriction enzymes and sequencing. HapMap data were used for comparison of allelic frequencies with the normal population by χ2 test to identify significant associations between genotypes and the presence of aneurysms. RESULTS Two hundred sixty-nine patients were enrolled into the study. There was a significant correlation with the presence of aneurysms for the GC allele of the SNP rs42524 in exon 28 (P = .02). The other polymorphisms did not show significant correlations. CONCLUSIONS The COL1A2 gene is associated with intracranial aneurysms in a subset of the German population. However, it is not responsible for the majority of aneurysms, and further candidate genes need to be identified to develop sensitive genetic screening for patients at risk.

Comparative Study of C-Arms for Intraoperative 3-Dimensional Imaging and Navigation in Minimally Invasive Spine Surgery Part I - Applicability and Image Quality.

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.

Minimally invasive tubular microdiscectomy for recurrent lumbar disc herniation

OBJECTIVE 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.

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.

Minimally invasive redo discectomy for recurrent lumbar disc herniations

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.

Hemangioblastomas and Neurogenic Polyglobulia

BACKGROUND Neurogenic polyglobulia occurs with central nervous system hemangioblastomas. Among the suggested mechanisms are extramedullary hematopoiesis in the tumor tissue and germline mutations of the von Hippel-Lindau (VHL) tumor suppressor gene. OBJECTIVE To determine the frequency and driving mechanisms of polyglobulia in central nervous system hemangioblastomas. METHODS We performed a retrospective analysis of pre- and postoperative (at 3 and 12 months) hemoglobin levels in a consecutive series of patients with hemangioblastomas operated on in our institution from 1996 to 2009. We performed molecular genetic analyses for mutations of the VHL tumor suppressor gene. RESULTS Preoperative hemoglobin levels were available from 164 patients. The average hemoglobin level (15.2 g/dL in males and 13.1 g/dL in females) was within normal range according to our standards. Of 22 patients with increased preoperative hemoglobin levels (>17 g/dL in males and >15 g/dL in females), 8 presented with pathological hemoglobin (>18.5 g/dL in males and >16.5 g/dL in females) according to World Health Organization criteria. Surgical removal of the hemangioblastoma resulted in a permanent cure of polyglobulia in all patients. Six of the 8 patients with pathological hemoglobin elevation carried a germline mutation of the VHL tumor suppressor gene. CONCLUSION Neurogenic polyglobulia occurs in a subset of patients with hemangioblastomas. This phenomenon is mostly observed in VHL mutation carriers, but also occurs in patients with sporadic hemangioblastomas. Removal of the tumor results in the permanent cure of polyglobulia. Our observations suggest that polyglobulia is an effect by the tumor itself, either due to paraneoplasia or extramedullary hematopoiesis.