Ludomir Stefańczyk

Clinical application of 3D pre-bent titanium implants for orbital floor fractures

INTRODUCTION Orbital structures are affected in approximately 40% of all cases of craniofacial trauma. Changes in the bony orbital dimensions can alter the function of intraorbital contents and lead to serious complications. The unique anatomy of the orbit and the resulting surgical approaches make the process of fitting and aligning implants difficult, time consuming and operator dependent. It is now possible to make relatively inexpensive anatomical models on the basis of computed tomography images, using rapid prototyping. Such models can be used as templates to form titanium mesh implants, which are then used in the reconstruction of orbital floor defects. MATERIAL AND METHODS Six patients with facial trauma were included in this study. First, 3D virtual models and then physical models were created. These were used as templates to shape the titanium mesh and then intraoperatively as guides to aid correct implant placement in the orbit. RESULTS Significant improvement resulted in three cases and total recovery in three cases. CONCLUSION It is financially viable to build anatomical models, on the basis of CT studies, that can be used in the repair of orbital floor fractures.

Cortical mapping by functional magnetic resonance imaging in patients with brain tumors

The aim of our study was to establish the effectiveness of the functional MRI (fMRI) technique in comparison with intraoperative cortical stimulation (ICS) in planning cortex-saving neurosurgical interventions. The combination of sensory and motor stimulation during fMRI experiments was used to improve the exactness of central sulcus localization. The study subjects were 30 volunteers and 33 patients with brain tumors in the rolandic area. Detailed topographical relations of activated areas in fMRI and intraoperative techniques were compared. The agreement in the location defined by the two methods for motor centers was found to be 84%; for sensory centers it was 83%. When both kinds of activation are taken into account this agreement increases to 98%. A significant relation was found between fMRI and ICS for the agreement of the distance both for motor and sensory centers (p=0.0021–0.0024). Also a strong dependence was found between the agreement of the location and the agreement of the distance for both kinds of stimulation. The spatial correlation between fMRI and ICS methods for the sensorimotor cortex is very high. fMRI combining functional and structural information is very helpful for preoperative neurosurgical planning. The sensitivity of the fMRI technique in brain mapping increases when using both motor and sensory paradigms in the same patient.

The Aberrant Right Subclavian Artery (Arteria Lusoria): The Morphological and Clinical Aspects of One of the Most Important Variations—A Systematic Study of 141 Reports

The most important abnormality of the aortic arch is arguably the presence of an aberrant right subclavian artery (arteria lusoria). If this vessel compresses the adjacent structures, several symptoms may be produced. The aim of the study is to present the morphological and clinical aspects of the aberrant right subclavian artery. Three different databases searched for a review of pertinent literature using strictly predetermined criteria. Of 141 cases, 15 were cadaveric and 126 were clinically documented. The gender distribution of the subjects was 55.3% female and 44.7% male. The mean age of the patients at symptoms onset was 49.9 ± 19.4 years for all patients but 54.0 ± 19.6 years and 44.9 ± 18.1 years for female and male subjects, respectively (P = 0.0061). The most common symptoms in this group were dysphagia (71.2%), dyspnea (18.7%), retrosternal pain (17.0%), cough (7.6%), and weight loss (5.9%). The vascular anomalies coexisting with an arteria lusoria were truncus bicaroticus (19.2%), Kommerells diverticulum (14.9%), aneurysm of the artery itself (12.8%), and a right sided aortic arch (9.2%). In conclusion, compression of adjacent structures by an aberrant right subclavian artery needs to be differentiated from other conditions presenting dysphagia, dyspnea, retrosternal pain, cough, and weight loss.

Technical concept of patient-specific, ultrahigh molecular weight polyethylene orbital wall implant

INTRODUCTION The authors have been using patient-specific implants since 2006 and are constantly looking for new reconstructive materials, in order to create precise implants for orbital reconstruction. Such materials should be biocompatible and stable in the human body, as well as easy to machine and form into complex 3D shapes. Biocompatible ultrahigh molecular weight polyethylene (UHMW-PE) has several unique properties including high impact strength and a low friction coefficient that result in self-lubricating and thus non-sticking surfaces after processing. AIM To present the concept of a patient-specific, UHMW-PE orbital wall implant. MATERIALS AND METHODS The material used to manufacture the orbital implant was UHMW-PE converted into a solid block of medical polymer from a powder material. A delayed treatment unilateral orbital fracture case was chosen for reconstruction with patient-specific orbital wall implant. On the basis of computerized tomography, a virtual model of both orbits was prepared. The injured orbit was significantly enlarged due to dislocation of its walls. The 3D model of the facial skeleton was symmetrically divided into two parts. This resulted in two models - left and right orbit, then the uninjured orbit was superimposed onto the contralateral side. As a result two surfaces were created; the outer surface (taken from the injured orbit) was used to design the outer surface of the implant, and the inner (taken from the uninjured orbit) for the inner surface. By combining both these surfaces it was possible to determine the unique shape and thickness of the UHMW-PE implant that would allow for accurate reconstruction of the orbit. Following this, the CAD model was transferred to CAM software and a numerical code for a 5-axis milling machine was generated. The manufactured implant was sterilized in gas plasma and used to reconstruct three orbital walls. RESULTS The thickness of the manufactured implant ranged from 0.2 mm to 1.5 mm and was successfully inserted via transconjunctival approach. The lower, medial and lateral walls were reconstructed. The correct position of the right eyeball was re-established by moving it upward and medially, which resulted in enophthalmos and diplopia correction. The described method features several advantages: accurate reconstruction of the original shape of the orbit, precise modification of local implant thickness during design of the CAD model, structural globe support combined with a thin implant, the possibility of repairing large orbital floor defects, corrections using scissor/scalpel during surgery are relatively uncomplicated, low level of morbidity, smooth edges and gradual, controlled variations in implant thickness between different regions. Disadvantages: changes to the curvature of the implant cannot be made during surgery, implant may require fixing with screws to be stabilized during the early phase of healing, long time required to design and manufacture implants (pre-op) and also UHMW-PE implants are radiolucent and cannot be imaged using X-rays. CONCLUSION UHMW-PE appears to have numerous advantages as a material for precise reconstruction of the orbits. Such patient-specific implants are durable, can even be used to reconstruct very thin walls, do not exhibit the high degree of morbidity typical for autogenous bone grafts and result in restoration of vision function.

Serum osteoprotegerin is a predictor of progression of atherosclerosis and coronary calcification in hemodialysis patients.

Background: The aim of this prospective cohort study was to evaluate the progression of coronary artery calcification (CAC), and atherosclerosis in hemodialysis (HD) patients and to relate them to novel biomarkers, i.e. serum osteoprotegerin (OPG) and fibroblast growth factor 23 (FGF-23). Material and Methods: Forty-seven HD patients were followed up for 30 months or until death. Intima media thickness (CCA-IMT), atherosclerotic plaques and CAC were assessed at baseline and after 30 months. Serum mineral parameters, lipids, OPG and plasma FGF-23 were also measured. Results: At baseline, 70% HD patients presented detectable CAC. The patients without calcification at baseline remained calcification free at 30 months and presented lower serum OPG and FGF-23 than those with CAC. A 64.4% progression of CAC was observed in all patients with CAC at baseline. In parallel, a 13% increase in CCA-IMT was found. Both ΔCAC and ΔCCA-IMT correlated positively with baseline and follow-up serum OPG. The patients who died had significantly higher baseline CAC and serum OPG. Conclusion: The plasma level of OPG could serve as a surrogate marker of progression of atherosclerosis and calcification in patients with end-stage renal disease. Therefore, the serum OPG may be a candidate biomarker of cardiovascular complications and poor outcome among dialysis patients.

Treatment with individual orbital wall implants in humans – 1-Year ophthalmologic evaluation

BACKGROUND In 2009 a method of creating individual, patient specific orbital wall implants using rapid prototyping (RP) was shown in a preliminary human study. That study showed that it is financially viable to produce anatomical models and that this technology could be used in the repair of orbital floor fractures. MATERIALS AND METHODS In this study, 24 consecutive subjects who had sustained orbital fractures (14 males, 6 females) without any coexisting central nervous system or globe injury were assessed post-operatively. The first series of 12 patients, recruited during the period 2005-2006, were treated with classical method (CM) of forming titanium mesh by manual manipulation, based on individual subjective assessment of the extent and shape of damaged orbital walls. The following 12 cases, recruited between 2007 and 2008, were treated with patient specific titanium mesh implants designed with an RP method. Early (2 weeks) and late (12 months) follow-up was performed. Patients were evaluated by binocular single vision (BSV) test and an assessment of eye globe motility. RESULTS The superiority of the RP treatment method over CM was shown on the basis of early results when BSV loss area and reduction of vertical visual disparity (VVD) in upgaze were considered. Better outcomes for the RP group were confirmed in the late follow-up results which showed a reduction of BSV loss area, correction of primary globe position and a very significant improvement in upgaze. CONCLUSIONS One-year post-operatively, functional assessment of pre-bent individual implants of the orbital wall has shown the technique to be a predictable reconstruction method. Nevertheless longer follow-up and an increase in the number of cases treated are required for the full evaluation of the technique.

Hand exercise test for the assessment of endothelium-dependent vasodilatation in subjects with type 1 diabetes.

BACKGROUND At present, endothelial dysfunction is best assessed in vivo with measurement of flow-mediated dilatation (FMD) with Doppler ultrasound scanning. This test, however, does not account for the subjects age and is uncomfortable for patients. The aim of the study was to compare a new test for endothelium function assessment using hand exercise load. METHODS The study group comprised 31 male patients with type 1 diabetes and 72 healthy men as controls. The subjects in both groups were subdivided into three age groups: 18-30 (subgroup A), 31-45 (subgroup B), and 46-60 (subgroup C) years. FMD of the brachial artery with induction of hand ischemia was conducted in all the subjects. Afterwards, an originally designed test using standardized hand exercise with the use of a training device was performed. RESULTS In the youngest group of type 1 diabetes patients the effect of hand ischemia on brachial artery diameter was greater than in the two older age subgroups: baseline artery diameter increased by 0.23 +/- 0.11 mm (5.7%), 0.19 +/- 0.09 mm (4.3%), and 0.13 +/- 0.02 mm (2.8%), respectively (P < 0.01). In the hand exercise test, artery diameter increased in the youngest subjects by 0.39 +/- 0.11 mm (9.5%) and in the two older groups by 0.26 +/- 0.07 mm (5.6%) and 0.18 +/- 0.09 mm (4.5%) (P < 0.05), respectively. In subgroups A, B and C, vasodilation after hand exercise test was greater by 67%, 30%, and 32% (P < 0.01), respectively, compared with the effect of the ischemic test. In the controls similar effects and relationship between ischemic and hand exercise tests were noted, however, with a smaller difference between the two tests. CONCLUSIONS The hand exercise test results in a greater difference in vessel diameter before and after the test stimulus, which might substantially improve its feasibility. The hand exercise test could be a useful alternative tool for endothelial function assessment, especially in type 1 diabetes subjects.

Endothelium‐dependent and ‐independent vasodilation is more attenuated in ischaemic than in non‐ischaemic heart failure

Endothelial dysfunction in chronic heart failure (CHF) contributes to vasoconstriction. Underlying atherosclerosis may increase vascular abnormalities in ischaemic CHF. We aimed to compare flow‐mediated dilation (FMD) and nitroglycerin‐mediated dilation (NMD) of the brachial artery between patients with ischaemic and non‐ischaemic CHF.

Numerical simulations of the blood flow in the patient-specific arterial cerebral circle region

The Cerebral Circle Region, also known as the Circle of Willis (CoW), is a loop of arteries that form arterial connections between supply arteries to distribute blood throughout the cerebral mass. Among the population, only 25% to 50% have a complete system of arteries forming the CoW. 3D time-varying simulations for three different patient-specific artery anatomies of CoW were performed in order to gain a better insight into the phenomena existing in the cerebral blood flow. The models reconstructed on the basis of computer tomography images start from the aorta and include the largest arteries that supply the CoW and the arteries of CoW. Velocity values measured during the ultrasound examination have been compared with the results of simulations. It is shown that the flow in the right anterior artery in some cases may be supplied from the left internal carotid artery via the anterior communicating artery. The investigations conducted show that the computational fluid dynamic tool, which provides high resolution in both time and space domains, can be used to support physicians in diagnosing patients of different ages and various anatomical arterial structures.

Supplementation of antipsychotic treatment with sarcosine – GlyT1 inhibitor – causes changes of glutamatergic 1NMR spectroscopy parameters in the left hippocampus in patients with stable schizophrenia

Glutamatergic system, the main stimulating system of the brain, plays an important role in the pathogenesis of schizophrenia. Hippocampus, a structure crucial for memory and cognitive functions and rich in glutamatergic neurons, is a natural object of interest in studies on psychoses. Sarcosine, a glycine transporter (GlyT-1) inhibitor influences the function of NMDA receptor and glutamate-dependent transmission. The aim of the study was to assess the effects of sarcosine on metabolism parameters in the left hippocampus in patients with schizophrenia. Assessments were performed using proton nuclear magnetic resonance ((1)H NMR) spectroscopy (1.5T). Fifty patients diagnosed with schizophrenia (DSM-IV-TR), with dominant negative symptoms, in stable clinical condition and stable antipsychotics doses were treated either with sarcosine (n=25) or placebo (n=25). Spectroscopic parameters were evaluated within groups and between two groups before and after 6-month intervention. All patients were also assessed with the Positive and Negative Syndrome Scale (PANSS). In the sarcosine group, after 6-month treatment, we found significant decrease in hippocampal Glx/Cr (Glx-complex of glutamate, glutamine and GABA, Cr-creatine) and Glx/Cho (Cho-choline), while N-acetylaspartate (NAA), myo-inositol (mI), Cr and Cho parameters remained stable along the study and also did not differ significantly between both groups. This is the first study showing that a pharmacological intervention in schizophrenia, particularly augmentation of the antypsychotic treatment with sarcosine, may reverse the pathological increase in glutamatergic transmission in the hippocampus. The results confirm involvement of glutamatergic system in the pathogenesis of schizophrenia and demonstrate beneficial effects of GlyT-1 inhibitor on the metabolism in the hippocampus and symptoms of schizophrenia.