Comparison of deep wound infection rates using a synthetic dural substitute (neuro-patch) or pericranium graft for dural closure: a clinical review of 1 year

OBJECTIVE: The need to repair dural defects has prompted the use of dura mater substitutes. Many synthetic materials have been used for dural closure. Neuro-Patch (B. Braun Médical S.A., Boulogne, France) is a nonabsorbable microporous fleece composed of polyester urethane that has been approved for human use by the European Union since 1995. To the best of our knowledge, no clinical series with Neuro-Patch have been published thus far, particularly with regard to septic complications. The aim of our study was to compare the safety of Neuro-Patch with that of pericranium graft with regard to postoperative wound infections. METHODS: This is a retrospective study of 1 year's experience including all patients who underwent dural plasty with a Neuro-Patch (n = 61) or pericranium graft (n = 63). The follow-up period was at least 12 months after surgery. Before wound infection rates in the two groups were compared, factors suspected of being risks for neurosurgical site infection were evaluated. RESULTS: Patient characteristics (mean age, neurological diagnosis), surgical procedures, prophylactic antibiotics, and risk factors for surgical infections (including duration of surgery, emergency, contaminated operations, and external cerebrospinal fluid drainage) were similar in the Neuro-Patch and pericranium groups. Deep wound infection rates in the Neuro-Patch and pericranium groups were 15 and 5%, respectively (P = 0.06), and cerebrospinal fluid leaks were significantly more frequent in the Neuro-Patch group (13 versus 1.6%, P < 0.05). CONCLUSION: The results of our investigations show that Neuro-Patch raised the risk of wound infection, as do foreign materials implanted in the body. Synthetic dural grafts should be reserved for when autologous grafts are not sufficient or possible. An extensive prospective multicenter randomized trial is needed to confirm our results.     

Anterior cruciate ligament reconstruction using navigation: a comparative study on 60 patients

BACKGROUND: Poor outcome in anterior cruciate ligament reconstruction is often related to tunnel position. HYPOTHESIS: Improving accuracy of the tunnel position will lead to improved outcome. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Sixty patients were randomized to either standard instrumentation or computer-assisted guides to position the tibial and femoral tunnels. The results were evaluated on clinical outcome based on International Knee Documentation Committee form (laxity) and radiologic assessment: radiologic Lachman (Telos at 150 and 200 N) and analysis of the tunnel positions. RESULTS: International Knee Documentation Committee laxity was level A in 22 knees in the conventional group (mean, 1.5 mm at 200 N) compared with 26 navigated knees (mean laxity, 1.3 mm; P = .49). Laxity was less than 2 mm in 96.7% of the navigated group and 83% of the conventional group (P = .292). The variability of laxity in the navigated group was significantly less than in the conventional group, with the standard deviation of the navigated group being smaller than that in the conventional group (P = .0003 at 150 N and .0005 at 200 N Telos). A significant difference (P = .03) was found between the groups in the ATB value (distance between the projection of the Blumensaat line on the tibial plateau and the anterior edge of the tibial tunnel), characterizing the sagittal position of the tibial tunnel (negative ATB values imply graft impingement in extension). In the conventional group, mean ATB was -0.2 (-5 to +4), whereas it was 0.4 (0 to 3) in the navigated patients. There were no negative ATB values in the navigated group. CONCLUSION: This study confirms that the accuracy and consistency of tibial tunnel position can be improved by the use of computer-assisted navigation and that the clinical result in terms of laxity is more reliable.     

Effect of age on anticipatory postural adjustments in unilateral arm movement

Aging is frequently accompanied by a deterioration in postural control. Accordingly, the elderly adopt postural strategies in order to maintain balance. The purpose of this study was to compare anticipatory postural adjustments in (healthy) 10 young and 10 elderly subjects using electromyography (EMG) and biomechanical parameters. While standing on a force platform, subjects performed voluntary, arm-raising movements under five conditions: self-paced at three different velocities, self-paced with load and an externally triggered, both at maximal velocity. The force platform provided information on vertical torque (T(z)) and center of pressure anteroposterior displacements (COP). EMG activity was recorded from the biceps femoris, quadriceps, tibialis anterior and soleus muscles. Voluntary movements were associated with an early COP backward shift and an anticipatory T(z). At low velocity, elderly subjects did not show any impairment in stability. At maximal velocity, T(z) was delayed in all conditions in the elderly group, whereas COP latency was reduced only in the self-paced condition without load. Despite this decrease in anticipation, the movement was performed at the same velocity as in younger subjects. The elderly adopted various muscle strategies in order to perform the same movement with less stability. In the self-paced condition, elderly subjects used a hip strategy, whereas young subjects used an ankle strategy. In the triggered condition, the strategy corresponded to increased activation of certain thigh muscles, rather than a sequence modification. Hence, local muscle strategies were used to counteract the overall delay in postural preparation revealed by biomechanical parameters.     

Intrinsic risk factors for the development of achilles tendon overuse injury: a prospective study

BACKGROUND: Although Achilles tendon overuse injuries occur commonly, our understanding of the pathologic changes and the factors that predispose athletes to them is limited. PURPOSE: To identify measurable intrinsic risk factors for Achilles tendon overuse injuries. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. METHODS: Sixty-nine male officer cadets followed the same 6-week basic military training. Before this training, each subject was evaluated for anthropometrical characteristics, isokinetic ankle muscle strength, ankle joint range of motion, Achilles tendon stiffness, explosive strength, and leisure and sports activity. During military training, Achilles tendon overuse injuries were registered and diagnosed by the same medical doctor. To identify the intrinsic risk factors, a multivariate analysis with the use of stepwise logistic regression was performed. The sensitivity, specificity, and cutoff values of the risk factors were evaluated by receiver operating characteristic curve analysis. RESULTS: Ten of the 69 male recruits (14.5%) sustained an Achilles tendon overuse injury diagnosed on the basis of medical history and clinical examination. Analysis revealed that male recruits with lower plantar flexor strength and increased dorsiflexion excursion were at a greater risk of Achilles tendon overuse injury. The cutoff value of the plantar flexor strength at 85% sensitivity was 50.0 N.m, with a 4.5% specificity; the cutoff value of the dorsiflexion range of motion at 85% sensitivity was 9.0 degrees , with 24.2% specificity. CONCLUSIONS: The strength of the plantar flexors and amount of dorsiflexion excursion were identified as significant predictors of an Achilles tendon overuse injury. A plantar flexor strength lower than 50.0 N.m and dorsiflexion range of motion higher than 9.0 degrees were possible thresholds for developing an Achilles tendon overuse injury.     

Multipolar radiofrequency ablation with internally cooled electrodes: experimental study in ex vivo bovine liver with mathematic modeling

PURPOSE: To evaluate the size and geometry of thermally induced coagulation by using multipolar radiofrequency (RF) ablation and to determine a mathematic model to predict coagulation volume. MATERIALS AND METHODS: Multipolar RF ablations (n = 80) were performed in ex vivo bovine livers by using three internally cooled bipolar applicators with two electrodes on the same shaft. Applicators were placed in a triangular array (spacing, 2-5 cm) and were activated in multipolar mode (power output, 75-225 W). The size and geometry of the coagulation zone, together with ablation time, were assessed. Mathematic functions were fitted, and the goodness of fit was assessed by using r(2). RESULTS: Coagulation volume, short-axis diameter, and ablation time were dependent on power output and applicator distance. The maximum zone of coagulation (volume, 324 cm(3); short-axis diameter, 8.4 cm; ablation time, 193 min) was induced with a power output of 75 W at an applicator distance of 5 cm. Coagulation volume and ablation time decreased as power output increased. Power outputs of 100-125 W at applicator distances of 2-4 cm led to a reasonable compromise between coagulation volume and ablation time. At 2 cm (100 W), coagulation volume, short-axis diameter, and ablation time were 66 cm(3), 4.5 cm, and 19 min, respectively; at 3 cm (100 W), 90 cm(3), 5.2 cm, and 22 min, respectively; at 4 cm (100 W), 132 cm(3), 6.1 cm, and 27 min, respectively; at 2 cm (125 W), 56 cm(3), 4.2 cm, and 9 min, respectively; at 3 cm (125 W), 73 cm(3), 4.9 cm, and 12 min, respectively; and at 4 cm (125 W), 103 cm(3), 5.5 cm, and 16 min, respectively. At applicator distances of 4 cm (>125 W) and 5 cm (>100 W), the zones of coagulation were not confluent. Coagulation volume (r(2) = 0.80) and RF ablation time (r(2) = 0.93) were determined by using the mathematic model. CONCLUSION: Multipolar RF ablation with three bipolar applicators may produce large volumes of confluent coagulation ex vivo. A compromise is necessary between prolonged RF ablations at lower power outputs, which produce larger volumes of coagulation, and faster RF ablations at higher power outputs, which produce smaller volumes of coagulation.     

Comparison of Gadolinium-BOPTA and Ferucarbotran-enhanced three-dimensional T1-weighted dynamic liver magnetic resonance imaging in the same patient

OBJECTIVES: We sought to compare signal changes using Ferucarbotran and gadobenate dimeglumine (Gd-BOPTA) in dynamic 3D T1-weighted (T1w) GRE imaging of the liver. MATERIAL AND METHODS: Thirty patients were prospectively included in the study. All patients underwent 2 high-field magnetic resonance (MR) examinations: first with Gd-BOPTA (Gd) and then after a mean interval of 4 days with ferucarbotran (Feru). Dynamic MRI was obtained with a 3D T1w GRE sequence (TR 6.33, TE 2.31, flip angle 20 degrees ). Contrast enhanced scans were assessed before intravenous injection of the contrast agent (precontrast), and postcontrast during the arterial phase (30 seconds), portal venous phase (60 seconds), and equilibrium phase (120 seconds). The signal intensities (SIs) of liver, spleen, aorta, and portal vein were defined by region of interest measurements. Signal intensity changes (SICs) and percentage signal intensity change (PSIC) were calculated using the formulas SIC=(SI pre - SI post)/SI pre and PSIC=SIC x 100%. RESULTS: Positive signal enhancement was observed after intravenous injection of Feru during all dynamic measurements, whereas the mean SI values were lower compared with Gd. During the portal venous phase the mean SI of Gd was up to a factor of 2.1 higher (portal vein). The widest difference of SIC was observed during the equilibrium phase for liver parenchyma (Gd, 1.03; Feru, 0.24). The dynamic signal courses were similar for liver, portal vein and aorta. Different signal courses were obtained for the spleen. CONCLUSIONS: Feru-enhanced T1w dynamic images demonstrated significant signal increases for liver, vessels, and spleen but overall lower signal intensities than Gd-BOPTA. The dynamic signal courses of ferucarbotran were similar to that of Gd-BOPTA during ll perfusion phases except in the spleen. Thus, it may be possible to detect typical enhancement pattern of focal liver lesions with Feru-enhanced dynamic T1w MRI.     

Preclinical safety and pharmacokinetic profile of ferumoxtran-10, an ultrasmall superparamagnetic iron oxide magnetic resonance contrast agent

OBJECTIVES: This report presents an overview of preclinical data available on ferumoxtran-10, an ultrasmall superparamagnetic iron oxide nanoparticular contrast agent proposed for lymph node magnetic resonance imaging. MATERIALS AND METHODS: Pharmacokinetic, safety pharmacology, single- and repeat-dose toxicity, reproduction toxicity, and genotoxicity studies were performed with ferumoxtran-10 given intravenously (bolus injection) in mice, rats, rabbits, dogs, and monkeys. RESULTS: Ferumoxtran-10 was taken up by macrophages, mostly in liver, spleen, and lymph nodes, within 24 hours after bolus injection and underwent progressive metabolism. Toxicity was observed only at very high exposure levels and mainly was linked to a massive iron load after repeated injections. Ferumoxtran-10 was not mutagenic but was teratogenic in rats and rabbits. DISCUSSION: The preclinical pharmacokinetic and safety profile of ferumoxtran-10 appears to be satisfactory in view of its proposed use as a single-dose diagnostic agent in human for MR imaging of lymph nodes.     

Effect of age and care organization on sources of variation in kidney transplant waiting list registration

Despite national guidelines, medical practices and kidney transplant waiting list registration policies may differ from one dialysis/transplant unit to another. Benefit risk assessment variations, especially for elderly patients, have also been described. The aim of this study was to identify sources of variation in early kidney transplant waiting list registration in France. Among 16 842 incident patients during the period 2016–2017, 4386 were registered on the kidney transplant waiting list at the start of, or during the first year after starting, dialysis (26%). We developed various log-linear mixed effect regression models on three levels: patients, dialysis networks, and transplant centers. Variability was expressed as variance from the random intercepts (± standard error). Although patient characteristics have an important impact on the likelihood of registration, the overall magnitude of variability in registration was low and shared by dialysis networks and transplant centers. Between-transplant center variability (0.23 ± 0.08) was 1.8 higher than between-dialysis network variability (0.13 ± 0.004). Older age was associated with a lower probability of registration and greater variability between networks (0.04, 0.20, & 0.93 in the 18–64, 65–74, and 75–84 age groups). Targeted interventions should focus on elderly patients and/or certain regions with greater variability in waiting list access.     

Thoracolumbar spine fractures in patients who have sustained severe trauma: depiction with multi-detector row CT

PURPOSE: To determine if multi-detector row computed tomography (CT) can replace conventional radiography and be performed alone in severe trauma patients for the depiction of thoracolumbar spine fractures. MATERIALS AND METHODS: One hundred consecutive severe trauma patients who underwent conventional radiography of the thoracolumbar spine as well as thoracoabdominal multi-detector row CT were prospectively identified. Conventional radiographs were reviewed independently by three radiologists and two orthopedic surgeons; CT images were reviewed by three radiologists. Reviewers were blinded both to one another's reviews and to the results of initial evaluation. Presence, location, and stability of fractures, as well as quality of reviewed images, were assessed. Statistical analysis was performed to determine sensitivity and interobserver agreement for each procedure, with results of clinical and radiologic follow-up as the standard of reference. The time to perform each examination and the radiation dose involved were evaluated. A resource cost analysis was performed. RESULTS: Sixty-seven fractured vertebrae were diagnosed in 26 patients. Twelve patients had unstable spine fractures. Mean sensitivity and interobserver agreement, respectively, for detection of unstable fractures were 97.2% and 0.951 for multi-detector row CT and 33.3% and 0.368 for conventional radiography. The median times to perform a conventional radiographic and a multi-detector row CT examination, respectively, were 33 and 40 minutes. Effective radiation doses at conventional radiography of the spine and thoracoabdominal multi-detector row CT, respectively, were 6.36 mSv and 19.42 mSv. Multi-detector row CT enabled identification of 146 associated traumatic lesions. The costs of conventional radiography and multi-detector row CT, respectively, were 145 and 880 US dollars per patient. CONCLUSION: Multi-detector row CT is a better examination for depicting spine fractures than conventional radiography. It can replace conventional radiography and be performed alone in patients who have sustained severe trauma.