[Postdural puncture headache after neuraxial anesthesia: incidence and risk factors]. / Postpunktioneller Kopfschmerz nach rückenmarknahen Anästhesieverfahren: Inzidenz und Risikofaktoren.

BACKGROUND/OBJECTIVE: Postdural puncture headache (PDPH) is a severe complication after spinal anesthesia. The aim of this study was to investigate the incidence of PDPH in two different operative cohorts and to identify risk factors for its occurrence as well as to analyze its influence on the duration of hospital stay. MATERIAL AND METHODS: In a retrospective study over a period of 3 years (2010-2012), 341 orthopedic surgery (ORT) and 2113 obstetric (OBS) patients were evaluated after spinal anesthesia (SPA). Data were statistically analyzed using (SPSS-23) univariate analyses with the Mann-Whitney U­test, χ2-test and Student's t-test as well as logistic regression analysis. RESULTS: The incidence of PDPH was 5.9% in the ORT cohort and 1.8% in the OBS cohort. Patients with PDPH in the ORT cohort were significantly younger (median 38 years vs. 47 years, p = 0.011), had a lower body weight (median 70.5 kg vs. 77 kg, p = 0.006) and a lower body mass index (median 23.5 vs. 25.2, p = 0.037). Body weight (odds ratio (97.5 % Confidence Intervall [CI]), OR 0.956: 97.5% CI 0.920-0.989, p = 0.014) as well as age (OR 0.963: 97.5% CI 0.932-0.991, p = 0.015) were identified as independent risk factors for PDPH. In OBS patients, PDPH occurred more frequently after spinal epidural anesthesia than after combined spinal epidural anesthesia (8.6% vs. 1.2%, p < 0.001) and the type of neuraxial anesthesia was identified as an independent risk factor for PDPH (OR 0.049; 97.5% CI 0.023-0.106, p < 0.001). In both groups the incidence of PDPH was associated with a longer hospital stay (ORT patients 4 days vs. 2 days, p = 0.001; OBS patients 6 days vs. 4 days, p < 0.0005). CONCLUSION: The incidence of PDPH was different in the two groups with a higher incidence in the ORT but considerably lower than in the literature. Age, constitution and type of neuraxial anesthesia were identified as risk factors of PDPH. Considering the functional imitations (mobilization, neonatal care) and a longer hospital stay, future studies should investigate the impact of an early treatment of PDPH.

Impact of brief prewarming on anesthesia-related core-temperature drop, hemodynamics, microperfusion and postoperative ventilation in cytoreductive surgery of ovarian cancer: a randomized trial.

BACKGROUND: General (GA)- and epidural-anesthesia may cause a drop in body-core-temperature (BCTdrop), and hypothermia, which may alter tissue oxygenation (StO2) and microperfusion after cytoreductive surgery for ovarian cancer. Cell metabolism of subcutaneous fat- or skeletal muscle cells, measured in microdialysis, may be affected. We hypothesized that forced-air prewarming during epidural catheter placement and induction of GA maintains normothermia and improves microperfusion. METHODS: After ethics approval 47 women scheduled for cytoreductive surgery were prospectively enrolled. Women in the study group were treated with a prewarming of 43 °C during epidural catheter placement. BCT (Spot on®, 3 M) was measured before (T1), after induction of GA (T2) at 15 min (T3) after start of surgery, and until 2 h after ICU admission (TICU2h). Primary endpoint was BCTdrop between T1 and T2. Microperfusion-, hemodynamic- and clinical outcomes were defined as secondary outcomes. Statistical analysis used the Mann-Whitney-U- and non-parametric-longitudinal tests. RESULTS: BCTdrop was 0.35 °C with prewarming and 0.9 °C without prewarming (p < 0.005) and BCT remained higher over the observation period (ΔT4 = 0.9 °C up to ΔT7 = 0.95 °C, p < 0.001). No significant differences in hemodynamic parameters, transfusion, arterial lactate and dCO2 were measured. In microdialysis the ethanol ratio was temporarily, but not significantly, reduced after prewarming. Lactate, glucose and glycerol after PW tended to be more constant over the entire period. Postoperatively, six women without prewarming, but none after prewarming were mechanical ventilated (p < 0.001). CONCLUSION: Prewarming at 43 °C reduces the BCTdrop and maintains normothermia without impeding the perioperative routine patient flow. Microdialysis indicate better preserved parameters of microperfusion. TRIAL REGISTRATION: ClinicalTrials.gov ; ID: NCT02364219 ; Date of registration: 18-febr-2015.

Spondylolysis and isthmic spondylolisthesis: impact of vertebral hypoplasia on the use of the Meyerding classification.

BACKGROUND: Spondylolysis and isthmic spondylolisthesis are common multifactorial disorders. The extent of slipping of the spondylolytic vertebra is considered a major predicator for prognosis and further follow-up. Vertebral hypoplasia is a common finding associated with spondylolysis. The purpose of this study is to evaluate the incidence of hypoplastic vertebral bodies in patients with spondylolysis and in the general population and to analyse the impact of the findings on the measurement and grading of spondylolisthesis. METHODS: 140 patients with 141 levels of spondylolysis identified by MRI were included in this study. The slippage of the spondylolytic vertebral body and the size in the midline sagittal image were measured and correlated. In addition, a randomised control group was evaluated to test the hypothesis that shortened, hypoplastic vertebral bodies can also be found in the general population. RESULTS: Shortened, hypoplastic vertebrae were found in 50 patients with spondylolysis and none was found in the control group. These shortened vertebrae mimicked spondylolisthesis and in 19 patients the slippage equalled the shortening, thus mimicking spondylolisthesis, although only spondylolysis was present. CONCLUSION: Sagittal shortening of the spondylolytic vertebra is common and may mimic spondylolisthesis. In order to define and measure spondylolisthesis the shortening of the spondylolytic vertebra has to be taken into account.

Positional venous MR angiography: an operator-independent tool to evaluate cerebral venous outflow hemodynamics.

BACKGROUND AND PURPOSE: CCSVI has been proposed as a cause for MS. According to this theory, strictures of the IJV are among the described causes for CCSVI. Little is known about their influence on the hemodynamics of the CVBO. We used positional MR imaging to describe the influence of positional changes on the CVBO. MATERIALS AND METHODS: Using the Fonar Upright MR imaging system, we performed venous time-of-flight angiography of the cervical region in the supine and sitting positions in 15 healthy volunteers. The image quality was rated; the positional findings and interindividual variances in the CVBO were analyzed. RESULTS: A venous time-of-flight angiography of the cervical spine was feasible with good image quality. Strictures of 1 or both IJVs were found in 8 of 15 healthy volunteers in the supine position; however, none were visible in upright position. The IJV was not the main outflow route in the erect position. No relevant venous reflux was observed. CONCLUSIONS: IJV strictures are a common finding in healthy volunteers in the supine position. They seem to be of no relevance in the erect position. This finding questions the validity of this criterion for the diagnosis of CCSVI. Reflux into the venous system was not visualized, and it remains to be seen whether it can be identified in patients with MS. Positional MR imaging enables operator-independent evaluation of the CVBO and may help to clarify the validity of the criteria for CCSVI.

Features of positional magnetic resonance imaging in tethered cord syndrome.

PURPOSE: Tethered cord syndrome (TCS) is a clinical entity in which symptoms are induced through excessive tension on the spinal cord. The radiological method of choice to confirm TCS is magnetic resonance imaging (MRI), however limitations exist especially in patients with no underlying spinal dysraphism. MATERIALS AND METHODS: The positional MRI features of TCS in a series of four patients with suspected or proven TCS are described, especially with respect to contact of the myelon or the cauda equina with the dorsal elements of the lumbar spinal canal. The findings are correlated with the lordosis angle of the lumbar spine. RESULTS: In flexion contact of the myelon or the cauda equina with the dorsal elements of the lumbar spinal canal is reduced due to a straightening of the lumbar spine. With increasing lordosis of the lumbar spine, the degree of contact increases and detection of TCS is more difficult. The site of tethering could be identified in all four patients in flexion. CONCLUSION: Positional MRI can be useful to confirm or rule out TCS and helpful to identify the site of tethering. The value of positional MRI is limited to patients who are able to fully flex the lumbar spine and in patients without spinal canal stenosis and spondylolisthesis.

Position dependent changes of the cerebral venous drainage--implications for the imaging of the cervical spine.

PURPOSE: This study demonstrates the physiological changes of the cerebral venous outflow routes in healthy humans in the recumbent and the sitting position employing positional MRI. METHODS: In five volunteers, the internal jugular veins and the cervical vertebral plexus were analyzed in the supine and sitting position using an open MR system. Axial T2-weighted scans and axial T1-weighted flow sensitive gradient echo sequences were acquired. The findings were compared to previously published anatomic descriptions from cadaver preparations. RESULTS: In the supine position, the internal jugular vein is the main route for the cerebral venous outflow. The mean area was 100 mm (2) (±29 mm (2)) for both sides together. In the sitting position, the jugular vein collapses (mean area: 11 mm (2)±2 mm (2)) and the vertebral venous plexus becomes more prominent. CONCLUSION: The position dependent changes in cerebral venous outflow can be imaged using positional MRI. The vertebral venous plexuses may mimic pathologies and physicians reading positional MRI images of the cervical spine should be aware of the physiological changes occurring in the erect position.

[Pathomechanisms of spinal canal stenosis - upright MRI image gallery]. / Pathomechanismen der spinalen Enge - Upright-MRT-Bildergalerie.

AIM: Lumbar spinal canal stenosis is a common disease of the elderly patient, with a high prevalence and clinical importance. MRI is the established method of choice for the imaging of spinal canal stenosis. However, there is often a discrepancy between the clinical symptoms and the spinal canal stenosis as shown using MRI in a supine position. In such cases preoperative functional imaging is often warranted. METHODS: In an image gallery three cases of a functional spinal canal stenosis of the lumbar spine are shown. In all three patients a dynamic, positional MRI (upright MRI) was performed. RESULTS: The pathomechanisms of the spinal canal stenosis could be shown in all three cases. CONCLUSION: Using upright MRI a functional spinal canal stenosis can be shown. The pathomechanisms of the spinal canal stenosis are discussed. The possibilities and limitations of this new imaging modality are presented and analysed.

Spondylolisthesis and posterior instability.

We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

Magnetic versus manual guidewire manipulation in neuroradiology: in vitro results.

INTRODUCTION: Standard microguidewires used in interventional neuroradiology have a predefined shape of the tip that cannot be changed while the guidewire is in the vessel. We evaluated a novel magnetic navigation system (MNS) that generates a magnetic field to control the deflection of a microguidewire that can be used to reshape the guidewire tip in vivo without removing the wire from the body, thereby potentially facilitating navigation along tortuous paths or multiple acute curves. METHOD: The MNS consists of two permanent magnets positioned on either side of the fluoroscopy table that create a constant precisely controlled magnetic field in the defined region of interest. This field enables omnidirectional rotation of a 0.014-inch magnetic microguidewire (MG). Speed of navigation, accuracy in a tortuous vessel anatomy and the potential for navigating into in vitro aneurysms were tested by four investigators with differing experience in neurointervention and compared to navigation with a standard, manually controlled microguidewire (SG). RESULTS: Navigation using MG was faster (P=0.0056) and more accurate (0.2 mistakes per trial vs. 2.6 mistakes per trial) only in less-experienced investigators. There were no statistically significant differences between the MG and the SG in the hands of experienced investigators. One aneurysm with an acute angulation from the carrier vessel could be navigated only with the MG while the SG failed, even after multiple reshaping manoeuvres. CONCLUSION: Our findings suggest that magnetic navigation seems to be easier, more accurate and faster in the hands of less-experienced investigators. We consider that the features of the MNS may improve the efficacy and safety of challenging neurointerventional procedures.

Fifteen-year follow-up of a patient with beta thalassaemia and extramedullary haematopoietic tissue compressing the spinal cord.

A long-term follow-up of a patient with beta thalassaemia with intra- and extraspinal extramedullary haematopoietic tissue compressing the spinal cord is presented. Extramedullary haematopoietic nodules are a rare cause of spinal cord compression and should be included in the differential diagnosis, especially in patients from Mediterranean countries. Treatment with radiation therapy solely failed, giving rise to the need of surgical intervention. Surgical decompression of the spine and the removal of the culprit lesion compressing the spine were performed. Postinterventional radiation therapy was applied to the spine. A relapse had to be treated again by surgical means combined with postinterventional radiation therapy. A complete relief of the symptoms and control of the lesion could be obtained.

Venocutaneous fistula.

This is the first description of venocutaneous fistula, a late complication of elective laparoscopic cholecystectomy that arose 18 months after the initial operation. Postoperatively, the patient twice developed an abscess in the abdominal wall at the former site of the umbilical trocar. The first abscess occurred on the 6th postoperative day; the second, after 14 months. After an additional 4 months, a fistula opening appeared just below the umbilicus. Fistulography revealed a connection with the venous system of the omentum majus. During subsequent resection of the fistula, a pigment gallstone was retrieved from the base of the fistula.

Peripheral directional atherectomy evaluated with a rotational digital angiography system.

BACKGROUND: One of the factors that affect the recurrence rate after peripheral directional atherectomy (DA) is the degree of residual stenosis. A new method of peripheral DA to reduce residual stenoses was evaluated with a rotational digital angiography (RDA) system that provides both angiography and fluoroscopy at multiple projections within 360 degrees. PATIENTS AND METHODS: Between March 1995 and July 1999, severe short segmental stenoses of six iliac arteries and two superficial femoral arteries (SFA) in eight patients were treated with the Simpson DA catheter under RDA system guidance. After pre-procedural RDA evaluation, the first series of DA were performed under ordinary PA fluoroscopic guidance. The residual stenoses were evaluated with RDA. If the residual stenoses exceeded 30%, a second series of DA were performed covering the residual plaque with the cutter window of the DA catheter. To this purpose the fluoroscopy of the RDA system was fixed in the direction in which the residual stenoses were largest and most eccentric. The end point was defined to be a residual stenosis of less than 30% evaluated with the RDA system, and the procedures were repeated until the end point was achieved. RESULTS: Five of six iliac artery lesions were curved at the pre-procedural RDA evaluation. After the first series of DA, only two of six iliac lesions but all SFA lesions achieved the end point. Among the four other iliac lesions, three achieved the end point with one or two additional series of DA using the RDA system guidance to control the selective cuts of the residual plaques. One patient had a residual stenosis of 50% because the procedure could not be completed by balloon rupture of the DA catheter. In the patients with iliac stenoses, there was no final residual stenosis in one, and the range was from 20% to 25% in the four patients. The residual stenoses were located on the greater curvature side of the curved artery in three of these four patients. CONCLUSION: The RDA system is a valuable tool in aiding reduction of the residual stenoses during peripheral DA. Minimal stenoses often remain on the greater curvature side of the wall because the rigid and straight metallic capsule (cylindrical housing) of the Simpson DA catheter does not completely fit the curved wall. This phenomenon was thought to be a mechanical limitation of this device.