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Biomedical subjects

A Schramm

Publications and source records attributed to A Schramm.

At least 19 recordsLinked to original sources
PubMed2007

[Navigated "targeted surgery" for skull base malignomas: additional space for surgical manipulation by neoadjuvant tumor downsizing].

BACKGROUND: Multimodal strategies are required due to the poor prognosis for locally advanced frontal skull base tumors staged as T4. Therefore, a further increase in the degree of invalidity caused by therapy should be avoided, if possible, to preserve the quality of life. As the incidence of these tumors is low, there are no evidence-based, generally accepted therapeutic strategies. METHODS: We evaluated the clinical results of three patients with extended frontal skull base malignomas staged as T4 tumors. The clinical course as well as the surgical technique were analyzed. RESULTS: High dose neoadjuvant therapy for tumor downsizing was performed in all three patients within a multimodal therapy concept. The additional space for surgical manipulation close to the tumor borders, non-traumatically produced by tumor remission, permitted a safely navigated, controlled resection of the tumor under endoscopic or microscopic viewing using an approach associated with reduced trauma as "targeted surgery". CONCLUSIONS: Surgical radicality is limited by the direct vicinity of locally progressive T4 tumors to the frontal brain and other vital structures. A controlled tumor downsizing allows the resection of such tumors using a minimally invasive approach assisted by instrumental navigation leading to less traumatization.

Adult↗
PubMed2006

Automatic extraction of the mid-facial plane for cranio-maxillofacial surgery planning.

Recently developed computer applications provide tools for planning cranio-maxillofacial interventions based on 3-dimensional (3D) virtual models of the patient's skull obtained from computed-tomography (CT) scans. Precise knowledge of the location of the mid-facial plane is important for the assessment of deformities and for planning reconstructive procedures. In this work, a new method is presented to automatically compute the mid-facial plane on the basis of a surface model of the facial skeleton obtained from CT. The method matches homologous surface areas selected by the user on the left and right facial side using an iterative closest point optimization. The symmetry plane which best approximates this matching transformation is then computed. This new automatic method was evaluated in an experimental study. The study included experienced and inexperienced clinicians defining the symmetry plane by a selection of landmarks. This manual definition was systematically compared with the definition resulting from the new automatic method: Quality of the symmetry planes was evaluated by their ability to match homologous areas of the face. Results show that the new automatic method is reliable and leads to significantly higher accuracy than the manual method when performed by inexperienced clinicians. In addition, the method performs equally well in difficult trauma situations, where key landmarks are unreliable or absent.

Algorithms↗
PubMed2006

[Objectivity of therapeutic results following skull base surgery using virtual model analysis].

BACKGROUND: Virtual model analysis of patient head tracking allows for objectivity and the monitoring of therapeutic results of pathologies in the skull base region. The introduction of these models in clinical routine has been impaired by the extended time needed for the preparation of radiological data. METHODS: Quality control analysis was carried out for seven cases with different pathological findings in the skull base region in patients who had undergone virtual model analysis. RESULTS: Preparation time of radiological data for the process of segmentation required, under optimal conditions, a minimum of 30 min. Virtual model analysis enables spatial visualization of regions of interest and adjacent anatomical structures. This improves case-specific pathoanatomical understanding as well as preoperative planning of surgical strategies. CONCLUSIONS: Virtual model analysis improves the physician's spatial comprehension of localized pathological findings at the dysmorphic interface of bone and soft tissue across the skull base. Therefore, it seems to be an adequate tool for quality control analysis of therapeutic results after extended skull base surgery.

Adolescent↗
PubMed2006

[Geriatrics in Bavaria-Database (GiB-DAT): Conception, structure and results of implementation (part I)].

In the year 2000, a database was implemented in Bavaria, covering the majority of geriatric clinics. Benchmarking statistics are generated in quarterly periods and scientifically analyzed. Actually, 41 of the 57 geriatric clinics in Bavaria participate in the project 'Geriatrics in Bavaria-Database' (GiB-DAT). For geriatric rehabilitation, the coverage is 82.4%. In addition, all 7 geriatric day clinics participate; thus, a total of 24,000 cases are documented each year. Therefore, GiB-DAT is the largest database for geriatric rehabilitation in Germany and Europe. To make documentation more effective and easy, new software (GERIDOCTM) has been generated which is integrated in the process of daily treatment. GiB-DAT offers good data quality, especially concerning completeness of items. This manuscript describes conception and construction of GiB-DAT and identifies differences compared to the Geriatric Minimum-Dataset (GEMIDAS), a nationwide geriatric database in Germany.

Aged↗
PubMed2006

[Geriatrics in Bavaria-Database (GiB-DAT): Basic data analysis of geriatric rehabilitation in Bavaria and analysis of inter-clinic variability (part II)].

OBJECTIVE: Presentation and comparison of basic data from geriatric rehabilitation in Bavaria with analysis of statistical influences on characteristic values like length of stay and Barthel Index. Are differences between participating clinics due to patient characteristics? SETTING: There were a total of 21 656 data records of the Geriatrics in Bavaria- Database (GiB-DAT) collected by 35 clinics within 1 year. RESULTS (PERCENTAGE OR MEAN): 70.6% female patients, age 80.0 years, 95.9% enrollment from acute care hospitals, length of stay in previous hospitals 24.3 days, length of stay in geriatric rehabilitation 24.6 days. DIAGNOSIS: 41.7% orthopedics, 24.9% neurological, 33.4% others. Barthel Index on admission 44.1 points, on discharge 65.8 points (difference 21.8 points). We found a large variance of all items between participating clinics. Variance for Barthel Index and length of stay is partly cleared up by regression analysis (multinomial logistic) and is mostly due to patient characteristics. CONCLUSIONS: Basic data of Bavarian geriatric rehabilitation clinics is matching with nationwide reference statistics. Differences exist for the lower rate of stroke and direct enrollment of outpatients. A simple ranking of outcome parameters (e. g. Barthel Index) does not make sense due to multiple influencing factors.

Aged↗
PubMed2006

Portal vein thrombosis uncommon clinical picture.

The authors described a case of the patient of the idiopatic group of PVT. Due to only a few symptoms, the diagnosis was established late. This was confirmed by the fact, that the patient was not hospitalized. So it was an atypical case of chronic PVT. Portal vein thrombosis belongs to rare clinical conditions. Early diagnosis based on modern technique is possible only if we keep this condition in mind (Tab. 1, Fig. 1, Ref. 23).

Aged↗
PubMed2005

[Computer assisted methods in reconstructive and function-preserving orbital surgery. New capabilities of computer assisted preoperative surgical planning (CAPP) and computer assisted surgery (CAS)].

BACKGROUND: Orbital reconstruction after tumor or trauma makes high demands on the surgeon when restoring the optic axis and cosmetic features. Computer-assisted preoperative planning surgery (CAPP) and computer-assisted surgery (CAS) allow calculation of the form of the orbital cavity to be reconstructed preoperatively as well as the process of its realization intraoperatively. METHODS: We developed new planning software methods for this surgical procedure. For validation the deviation of accuracy was assessed between the virtual and the real model in eight patients with surgical reconstruction of the orbit. RESULTS: The check of accuracy of the reconstructions compared to the planning of the surgery by fusion of preoperative and postoperative data resulted in a mean deviation of 1.74 mm. The volumetric measurements presented a mean deviation of 0.2 cm(3) with an accuracy of >99%. The accuracy of linear measurements with the techniques of image fusion of the "feature-based" method was 0.38 mm and thus close to the technical threshold of effective data accuracy of 0.35 mm. The enophthalmus could be assessed more objectively with this method compared to using the Hertel index. CONCLUSIONS: CAPP and CAS are helpful in reconstructive orbital surgery to verify the position of the optic axis and the cosmetic result intraoperatively.

Adult↗
PubMed2005

Carotid artery stenting in clinical practice results from the Carotid Artery Stenting (CAS)-registry of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausarzte (ALKK).

BACKGROUND: Carotid artery stenting (CAS) for symptomatic and asymptomatic carotid stenosis seems to be on the doorstep of more widespread use. However, its feasibility and safety in clinical practice at a broad spectrum of hospitals needs to be determined. METHODS: We analyzed data of the prospective multi-centre Carotid Artery Stenting (CAS) Registry of the German Arbeitsgemeinschaft Leitende Kardiologische Krankenhausarzte (ALKK). RESULTS: From 7/1996 to 5/2004 1888 patients from 28 hospitals were included in the CAS Registry. The median hospital stay from CAS until hospital discharge was 3 days (quartiles: 2-6 days). Median patients age was 70 years (quartiles: 64-76 years) with 72.1% males. CAS for symptomatic stenosis was performed in 55% of cases. Patients treated with CAS suffered from coronary artery disease in 66.5%, had arterial hypertension in 91.7%, hyperlipidemia in 86.3% and 34.2% were diabetics. The intended CAS procedure was completed in 98.1% of cases. A stent was implanted in 97.3% of completed cases. The median intervention time was 43 min (quartiles: 30-60 min). During the hospital stay death rate was 0.3% (5/1888) and the rate of ipsilateral stroke 3.2% (58/1840). A contralateral ischemic event occurred in 1.4% (26/ 1840) of patients. The combined rate of all death or strokes was 3.8% (70/1841). Between 1996 and 2004 there was a steady increase in the use of protection devices during CAS (0% in 1996 and 97.9% in 2004; p for trend <0.0001). There was also an increase in the proportion of patients treated for asymptomatic stenoses (p for trend <0.0001). We observed a decrease of the combined endpoint of death or stroke from 6.3% in 1996 to 1.9% in 2004 (p for trend=0.021). CONCLUSION: The multi-centre ALKK CAS Registry data confirm the feasibility and shot-term safety of CAS even in daily clinical practice. There was a rapid penetration of the use of embolic protection devices, an increase in treatment of asymptomatic carotid stenoses and a decrease in acute complication rates from 1996 to 2004.

Aged↗
PubMed2002

[Extraoral and intraoral endoscopically assisted management of collum fractures].

AIM OF THE STUDY: Using limited extraoral and transoral incisions for an endoscopically assisted open reduction of condylar mandible fractures, the risk of facial nerve damage and extensive visible scars can be reduced. PATIENTS AND METHODS: The endoscopically assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 14 had additional mandibular fractures, and 11 of the condylar fractures were dislocated. Of the 17 patients, 9 were treated by submandibular and 8 by transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approaches using an endoscopically assisted technique. APPROACHES: In four patients angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trocars were not needed in these four patients. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle even when dislocation with lateral override was present. The extraoral approach was used for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗
PubMed2002

[Color duplex ultrasound in monitoring vascularized fibula transplants].

BACKGROUND: For the successful management of vascularized free fibular bone grafts, the early detection of vascular complications is important. When vascular complications are suspected without a reliable monitoring of the graft perfusion, revision surgery often proved to be unnecessary. Color duplex sonography for the postoperative monitoring of free fibular bone grafts without a skin island is demonstrated. MATERIAL AND METHODS: The quantitative and qualitative monitoring of the perfusion of microvascular anastomosis and the transplanted tissues using color duplex sonography with a 7.5-Mhz scanner (Elegra, Siemens, Germany) for the postoperative monitoring of 12 free fibular bone grafts was performed. Using color duplex sonography, the perfusion of the vascular pedicle and the free fibular bone grafts was demonstrated in all 12 free fibular bone grafts. In three patients vascular complications and failure of the bone grafts were suspected due to postoperative complications next to free fibular bone grafts such as abscess formation, wound dehiscence, and disturbances of wound healing. Using color duplex sonography, adequate perfusion of the vascular pedicle and the transplanted tissue was demonstrated and therefore revision surgery not indicated. DISCUSSION: Color duplex sonography is a reliable, noninvasive, and inexpensive method for the postoperative monitoring of free fibular bone grafts.

Ameloblastoma↗
PubMed2002

Simultaneous P and N removal in a sequencing batch biofilm reactor: insights from reactor- and microscale investigations.

A sequencing batch biofilm reactor (SBBR) with well established enhanced biological phosphate removal (EBPR) was subjected to higher ammonium concentrations to stimulate and eventually implement simultaneous nitrification. Changes of activity and populations were investigated by a combination of online monitoring, microsensor measurements and fluorescence in situ hybridisation (FISH) of biofilm sections. Nitrification and nitrifying bacteria were always restricted to the periodically oxic biofilm surface. Both, activity and population size increased significantly with higher ammonium concentrations. Nitrification always showed a delay after the onset of aeration, most likely due to competition for oxygen by coexisting P accumulating and other heterotrophic bacteria during the initial aeration phase. This view is also supported by comparing oxygen penetration and oxygen uptake rates under low and high ammonium conditions. Therefore, simultaneous nitrification and phosphorus removal in a P removing SBBR appears to be only possible with a sufficiently long oxic period to ensure oxygen availability for nitrifiers.

Bacteria↗
PubMed2002

Endoscopy-assisted open treatment of condylar fractures of the mandible: extraoral vs intraoral approach.

By using an endoscopy assisted extraoral and transoral approach for open reduction of condylar mandible fractures with limited incisions, the risk of facial nerve damage and extensive visible scars can be reduced. The endoscopy-assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 13 presented with additional mandibular fractures. Nine of the 17 patients were treated by a submandibular approach and eight by a transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approach using an endoscopy-assisted technique. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle, even when dislocation with lateral override was present. In four patients, angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trochars were not needed in these four patients. The extraoral approach was indicated for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗
PubMed2001

Versatility and donor site morbidity of the lateral upper arm flap in intraoral reconstruction.

OBJECTIVE: The lateral upper arm flap is not widely used yet for intraoral defect reconstruction. Investigation of its morphologic and functional outcome was the objective of this study. STUDY DESIGN: The morphologic and functional results of recipient (swallowing, flap survival, dehiscence of margins, cutaneous fistulas, intraoral hairs) and donor sites (wound healing, scar width and length, sensory and motor disturbance) (n = 44) were checked clinically. Postoperative swallowing was investigated via videofluorography (n = 11). RESULTS: The lateral upper arm flap showed low donor site morbidity, primary closure was achieved in all but one case. Sensory deficit at the proximal forearm (n = 27) occurred without any case of compromise of radial nerve function. Videofluorography allows for objective evaluation of swallowing function. CONCLUSIONS: The lateral upper arm flap is the reconstruction of first choice for intraoral defects due to its low donor site morbidity.

Adult↗
PubMed2001

Community structure and activity dynamics of nitrifying bacteria in a phosphate-removing biofilm.

The microbial community structure and activity dynamics of a phosphate-removing biofilm from a sequencing batch biofilm reactor were investigated with special focus on the nitrifying community. O(2), NO(2)(-), and NO(3)(-) profiles in the biofilm were measured with microsensors at various times during the nonaerated-aerated reactor cycle. In the aeration period, nitrification was oxygen limited and restricted to the first 200 microm at the biofilm surface. Additionally, a delayed onset of nitrification after the start of the aeration was observed. Nitrate accumulating in the biofilm in this period was denitrified during the nonaeration period of the next reactor cycle. Fluorescence in situ hybridization (FISH) revealed three distinct ammonia-oxidizing populations, related to the Nitrosomonas europaea, Nitrosomonas oligotropha, and Nitrosomonas communis lineages. This was confirmed by analysis of the genes coding for 16S rRNA and for ammonia monooxygenase (amoA). Based upon these results, a new 16S rRNA-targeted oligonucleotide probe specific for the Nitrosomonas oligotropha lineage was designed. FISH analysis revealed that the first 100 microm at the biofilm surface was dominated by members of the N. europaea and the N. oligotropha lineages, with a minor fraction related to N. communis. In deeper biofilm layers, exclusively members of the N. oligotropha lineage were found. This separation in space and a potential separation of activities in time are suggested as mechanisms that allow coexistence of the different ammonia-oxidizing populations. Nitrite-oxidizing bacteria belonged exclusively to the genus Nitrospira and could be assigned to a 16S rRNA sequence cluster also found in other sequencing batch systems.

Ammonia↗
PubMed2000

Indications for computer-assisted treatment of cranio-maxillofacial tumors.

OBJECTIVE: Ablative tumor surgery requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). Reconstruction following tumor resection is dependent on reliable information for choosing the correct type and volume of grafts and predicting the outcome. This study evaluates the benefit of and the indications for computer-assisted surgery in the treatment of cranio-maxillofacial tumors. MATERIALS AND METHODS: Based on a CT or MRI data set, the STN Navigation System (Stryker-Leibinger) was used for preoperative planning, intraoperative navigation, and postoperative control of radical tumor resection and primary and secondary reconstruction. Tumor resection was preoperatively planned and intraoperatively navigated. Preoperatively, the required soft and hard tissue were measured using the mirrored data set of the unaffected side of the facial skeleton; the size and location of the graft were chosen virtually. Intraoperatively, contours of transplanted tissues were navigated in accordance with the preoperatively simulated reconstructive result. RESULTS: Computer-assisted treatment was successfully completed in all cases of radical tumor resection, and safety margins outlined preoperatively could be precisely controlled during tumor resection. Reconstruction was designed and performed exactly as virtually planned. CONCLUSIONS: Image-guided treatment improves preoperative planning by visualization of the individual anatomy and the intended reconstructive outcome, and by objectivation of the effect of adjuvant chemo-/radiotherapy. Intraoperative navigation makes radical tumor surgery more reliable by showing the determined safety margins, preserving vital structures, and guiding reconstruction to preplanned objectives.

Adolescent↗