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Biomedical subjects

K Ludwig

Publications and source records attributed to K Ludwig.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Surgical therapy in cholecysto-/choledocholithiasis. Results of a Germany-wide questionnaire sent to 859 clinics with 123,090 cases of cholecystectomy].

BACKGROUND: With the advent of laparoscopic cholecystectomy, the choice of procedure (laparoscopic vs open) and surgical management in gallstone disease are of interest. The purpose of this study was to examine the current approach and various strategies for cholecystectomy in Germany. METHODS: A retrospective survey at 859 (of 1,200, 67.6%) hospitals in Germany was conducted. Data from 123,090 patients that had undergone cholecystectomy were analyzed. RESULTS: 71.9% of the procedures were finished laparoscopically (LC: 88.537), whereas 22.5% (27.727) were done in the open technique (KC). Conversion to open surgery was required in 7.1% of the laparoscopically started operations, mainly in cases of adhesions and unclear anatomic situations (64.3%). When common bile duct (CBD) stones were diagnosed preoperatively, 74.4% of the participants favored primary endoscopic extraction (ERC), followed by LC. In cases of intraoperative diagnoses, the LC was finished and postoperative ERC and extraction were carried out in more than half of the hospitals (58.4%). Sixteen percent were converted to an open operation with simultaneous exploration of the CBD. Laparoscopic desobstruction of the CBD was extremely rare (4.4%). The intraoperative cholangiography (IOC) was the most strongly recommended approach for intraoperative diagnostics, but was generally routine practice in only 6% of the hospitals conducting LCs. Forty-nine percent of the respondents reported the use of IOC in selected cases and 43% of the hospitals did not perform any intraoperative diagnostics in LC. Compared with OC, the results show a lower incidence of postoperative reinterventions (0.9 vs 1.8%) and fatal outcomes (0.04 vs 0.53%) for LC. In contrast, CBD injuries were more frequent in the LC group (0.32 vs 0.12%). The median duration of hospitalization was 6.1 days (range 2.8-12) in the LC group compared with 10.4 days (range 3-28) in the OC group. CONCLUSIONS: LC is the standard procedure for the treatment of uncomplicated gallstone disease. Even after adjustment for differences in patient comorbidities, there are logical differences between the hospitals as to the type of cholecystectomy used for acute cholecystitis, the management of CBD stones, and the intraoperative diagnostics in LC.

Cholangiography↗
PubMed2001

[Gastrointestinal autonomic nerve tumor (GANT)--a rate tumor of the ileum].

The gastrointestinal autonomic nerve tumor (GANT) is an uncommon stromal tumor of the intestinal tract and retroperitoneum first described by Herrera and associates in 1984. GAN tumors, also termed "plexosarcomas", arise from autonomic nervous system plexuses of the gastrointestinal tract. We report a case of GAN tumor of the intestinal tract in a 63-year-old woman. The diagnosis is based on light microscopy and immunohistochemical analyses. The tumor stained positive for neuron-specific enolase (NSE) and S-100 protein and was negative for muscle markers. Pain and chronic and acute bleeding are the most frequent but not specific symptoms, and the diagnostic delay is reflected by a large diameter of these tumors. GAN tumors are fatal and must be considered malignant. They need radical surgical resection.

Diagnosis, Differential↗
PubMed2001

[Biomechanical study of angle-stable anterior atlanto-axial spondylodesis plate].

The optimum fixation method to achieve atlantoaxial fusion after odontoid resection is still subject to discussion. Isolated posterior surgical procedures for treatment of irreducible atlantoaxial kyphosis with spinal cord compression are associated with a high rate of morbidity and mortality. Transoral atlantoaxial plate fixation has been described by Harms as a fixation technique after odontoid resection. The purpose of this study was to compare biomechanically a new anterior atlantoaxial locking plate (AALP) with the Harms plate and the atlantoaxial transarticular screw fixation described by Magerl. Sixteen human cadaver craniocervical specimens were tested in flexion, extension, rotation, and bending with a nondestructive flexibility method using a nonconstrained testing apparatus. Five different groups were examined: (1) control group (intact) (n = 16), (2) unstable group (after dissection of the atlantoaxial ligaments and odontoidectomy) (n = 16), (3) Harms group (transoral atlantoaxial plate fixation) (n = 8), (4) AALP group (anterior atlantoaxial locking plate fixation) (n = 8), and (5) Magerl group (transarticular atlantoaxial screw fixation) (n = 16). Stiffness in any direction was significantly higher in the AALP specimens and those fixated with the Magerl method than in the Harms, control, or unstable specimens. The difference in stiffness between the AALP and Magerl reconstruction groups was not statistically significant. Experimentally, the AALP was significantly stiffer than the Harms plate. The AALP provided stiffness equal to transarticular screw fixation according to Magerl. A question that cannot be answered by this in vitro study concerns the level of rigidity required to obtain long-term stability and fusion by atlantoaxial fixation methods. However, it may be assumed that the more spinal motion is eliminated the greater the chance of definite spinal fusion. Therefore, it seems reasonable that the most reliable and rigid fixation method would be the method of choice.

Aged↗
PubMed2001

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.

Child↗
PubMed2001

Preoperative evaluation of limbal dermoids using high-resolution biomicroscopy.

BACKGROUND: Only a few case reports have described the ultrasound biomicroscopic features of limbal dermoids. It remains unclear whether examination by ultrasound biomicroscopy (UBM) can detect the corneal depth of penetration which would improve planning of surgery. METHODS: Eight consecutive patients [two female, six male, 1-24 years old (median 8.5 years)] examined by UBM (Zeiss-Humphrey, 50 MHz) were retrospectively studied. Five of the dermoids were excised without corneal grafting and histopathological evaluation was obtained. RESULTS: Seven out of eight dermoids were located in the temporal lower quadrant. A Goldenhar syndrome was known in three cases. In all cases but one, UBM showed a more reflective and predominantly homogeneous lesion compared with the unaffected corneal stroma, so that the lateral margins of the lesion could be clearly identified. Incomplete stromal penetration of the dermoid was noticed in four cases; one eye showed a corneal full thickness dermoid. An intraocular protrusion was seen in one eye. Two more cases remained unclear because of reduced compliance. Descemet's membrane beneath the dermoid could not be visualized in most cases (seven out of eight) because of strong sound attenuation inside the lesion. Histopathological evaluation of five cases revealed the typical signs of a limbal dermoid. CONCLUSION: UBM improves the preoperative evaluation of limbal dermoids. Subtle examination technique for the depth of corneal penetration is required because of the strong sound attenuation in this tissue, reducing the visibility of deep corneal structures.

Adolescent↗
PubMed2001

Complete response to neoadjuvant chemoradiation for rectal cancer does not influence survival.

BACKGROUND: Up to 30% of patients with locally advanced rectal cancer have a complete clinical or pathologic response to neoadjuvant chemoradiation. This study analyzes complete clinical and pathologic responders among a large group of rectal cancer patients treated with neoadjuvant chemoradiation. METHODS: From 1987 to 2000, 141 consecutive patients with biopsy-proven, locally advanced rectal cancer were treated with preoperative 5-fluorouracil-based chemotherapy and radiation. Clinical restaging after treatment consisted of proctoscopic examination and often computed tomography scan. One hundred forty patients then underwent operative resection, with results tracked in a database. Standard statistical methods were used to examine the outcomes of those patients with complete clinical or pathologic responses. RESULTS: No demographic differences were detected between either clinical complete and clinical partial responders or pathologic complete and pathologic partial responders. The positive predictive value of clinical restaging was 60%, and accuracy was 82%. By use of the Kaplan-Meier life table analysis, clinical complete responders had no advantage in local recurrence, disease-free survival, or overall survival rates when compared with clinical partial responders. Pathologic complete responders also had no recurrence or survival advantage when compared with pathologic partial responders. Of the 34 pathologic T0 tumors, 4 (13%) had lymph node metastases. CONCLUSIONS: Clinical assessment of complete response to neoadjuvant chemoradiation is unreliable. Micrometastatic disease persists in a proportion of patients despite pathologic complete response. Observation or local excision for patients thought to be complete responders should be undertaken with caution.

Aged↗
PubMed2001

Stochastic simulation of hemagglutinin-mediated fusion pore formation.

Studies on fusion between cell pairs have provided evidence that opening and subsequent dilation of a fusion pore are stochastic events. Therefore, adequate modeling of fusion pore formation requires a stochastic approach. Here we present stochastic simulations of hemagglutinin (HA)-mediated fusion pore formation between HA-expressing cells and erythrocytes based on numerical solutions of a master equation. The following elementary processes are taken into account: 1) lateral diffusion of HA-trimers and receptors, 2) aggregation of HA-trimers to immobilized clusters, 3) reversible formation of HA-receptor contacts, and 4) irreversible conversion of HA-receptor contacts into stable links between HA and the target membrane. The contact sites between fusing cells are modeled as superimposed square lattices. The model simulates well the statistical distribution of time delays measured for the various intermediates of fusion pore formation between cell-cell fusion complexes. In particular, these are the formation of small ion-permissive and subsequent lipid-permissive fusion pores detected experimentally (R. Blumenthal, D. P. Sarkar, S. Durell, D. E. Howard, and S. J., J. Cell Biol. 135:63-71). Moreover, by averaging the simulated individual stochastic time courses across a larger population of cell-cell-complexes the model also provides a reasonable description of kinetic measurements on lipid mixing in cell suspensions (T. Danieli, S. L. Pelletier, Y.I. Henis, and J. M. White, 1996, J. Cell Biol. 133:559-569).

Cell Fusion↗
PubMed2001

[Multi-slice spiral CT of the abdomen in oncological patients: influence of table support and detector configuration on image quality and radiation exposure].

PURPOSE: To evaluate the image quality and radiation exposure of different spiral CT scanning parameters for routine staging examination of the abdomen in oncologic patients using a multi-slice CT scanner. METHODS/MATERIALS: Examination of 40 patients in 4 groups on a multi-slice CT scanner (Somatom VolumeZoom, Siemens AG, Forchheim). Functional detector width (4 x 2.5, 4 x 5 mm) and pitch (table feed in relation to collimated slice width) were varied (3 and 5). Tube voltage (120 kV), effective tube current (160 mAs), slice-thickness (6 mm), increment (4 mm), kernel (B 30), and contrast injection parameters were kept constant. Axial images were assessed by three radiologists regarding delineation of anatomic structures, artifacts, and overall image quality. RESULTS: Significantly reduced image quality especially due to artifacts was observed using a 5 mm detector configuration with a pitch of 5 (scan time 9 sec). Image quality was rated best for a 2.5 mm detector configuration with a pitch of 3 and a scan time of 28 sec. The effective dose was independent of the pitch. However, the mean effective dose was 9% higher using the smaller detector configuration (9.9 mSv vs 10.9 mSv). CONCLUSIONS: For routine staging CT of the abdomen use of a 4 x 2.5 mm detector configuration with a pitch between 3 and 5 is recommended. A 4 x 5 mm detector configuration using overlapping data acquisition can also be recommended, but additional thin slice reformations are not possible.

Abdominal Neoplasms↗
PubMed2001

[Management of hemorrhage and perforation following endoscopic sphincterotomy].

Bleeding and perforation are rare but dangerous complications of diagnostic and therapeutic ERCP and endoscopic sphincterotomy (EST). To evaluate the clinical outcome of patients treated for complicated EST in our surgical department, data were collected prospectively between 1/1995 and 3/2000. A total of 9 patients were admitted to our department, 7 women and 2 men, average age 60 (range 41-72) years. 5 patients were treated for severe hemorrhage, all of them underwent laparotomy following duodenotomy and oversewing of the sphincterotomy site. In average 10 hours (range 4-20) after endoscopy. One of these patients died due to multiple organ failure. In 4 additional patients a retroperitoneal perforation was discovered, 2 of these patients underwent laparotomy and drainage of the retroperitoneal cavity. The other two patients were sufficiently treated by percutaneous drainage. One of the patients, who underwent surgical drainage for retroperitoneal perforation died. In conclusion for severe hemorrhage duodenotomy and oversewing of the bleeding site is recommended in combination with common bile duct T-drain or other draining procedures. The treatment for perforation should depend on the clinical finding. A laparotomy seems not always to be necessary.

Adult↗
PubMed2001

[An extended CT scale technique for evaluating periprosthetic bone lesions - an in vitro study].

PURPOSE: In the present study the reduction of artifacts using an extended CT scale technique was examined in 5 vitallium and 5 titanium-aluminium-vanadium tumor prostheses. METHODS: 5 titanium-aluminium-vanadium and 5 vitallium distal femur Mutars(R) tumor prostheses (Mutars(R) - Modular Universal Tumor And Revision System) were implanted in 10 human femur specimens. 110 artifical drill hole lesions of 1 mm, 2 mm, 3 mm, 5 mm and 8 mm diameter were placed in the bone around the hexagonal stem of the tumor prosthesis and furthermore in the proximal part of the femur. All specimens were examined using conventional CT and an extended CT scale technique in a slice thickness of 3 mm. RESULTS: In the proximal part of the femur all drill holes could be detected using 3 mm slices, no artefacts were observed. Along the hexagonal stem smooth lines arising from each hexagonal plane could be observed. This made it impossible to detect a 1 mm drill in 1 vitallium and in 1 titanium-aluminium-vanadium stem. There was no difference between the extended CT scale and conventional CT. CONCLUSION: The extended CT scale did not significantly (p > 0.05, t-test) improve the imaging of artificial drill hole lesions along the hexagonal Mutras(R) stem.

Aged↗
PubMed2001

Deep prosthesis infection in incisional hernia repair: predictive factors and clinical outcome.

OBJECTIVE: To evaluate the incidence of prosthetic infection in incisional hernia repairs, to determine whether there are any factors associated with prosthetic infection and to describe the clinical outcome. DESIGN: Retrospective clinical study. SETTING: Teaching hospital, Germany. SUBJECTS: 121 consecutive patients who underwent incisional hernia repair in our department from December 1994 to December 1999. INTERVENTION: Hernia repair by implantation of an alloplastic prosthesis by the Stoppa-Rives technique. MAIN OUTCOME MEASURES: Postoperative deep prosthetic infection and associated factors. RESULTS: All 121 patients had the mesh implanted in the subfascial plane, 77 had a polypropylene mesh (Prolene) (64%), 7 had a polyester mesh (Mersilene) (6%), and 37 patients had a expanded polytetrafluoroethylene patch (ePTFE, Gore-Tex) (31%). Postoperatively the mesh became infected in 8 patients (7%), a mean of 4.5 months (range 0.5-16) after hernia repair. All three infected ePTFE patches had to be removed whereas drainage was sufficient treatment for the infected polypropylene and polyester meshes. CONCLUSION: Once a mesh infection is verified adequate drainage seems to be sufficient for polypropylene and polyester meshes but ePTFE patches should be removed.

Aged↗
PubMed2001

Neoadjuvant chemoradiation for rectal cancer: analysis of clinical outcomes from a 13-year institutional experience.

OBJECTIVE: To examine clinical outcomes in patients receiving neoadjuvant chemoradiation for locally advanced rectal adenocarcinoma. SUMMARY BACKGROUND DATA: Preoperative radiation therapy, either alone or in combination with 5-fluorouracil-based chemotherapy, has proven both safe and effective in the treatment of rectal cancer. However, data are lacking regarding which subgroups of patients benefit from the therapy in terms of decreased local recurrence and increased survival rates. METHODS: A retrospective chart review was performed on 141 consecutive patients who received neoadjuvant chemoradiation (5-fluorouracil +/- cisplatin and 4,500-5,040 cGy) for biopsy-proven locally advanced adenocarcinoma of the rectum. Surgery was performed 4 to 8 weeks after completion of chemoradiation. Standard statistical methods were used to analyze recurrence and survival. RESULTS: Median follow-up was 27 months, and mean age was 59 years (range 28-81). Mean tumor distance from the anal verge was 6 cm (range 1-15). Of those staged before surgery with endorectal ultrasound or magnetic resonance imaging, 57% of stage II patients and 82% of stage III patients were downstaged. The chemotherapeutic regimens were well tolerated, and resections were performed on 140 patients. The percentage of sphincter-sparing procedures increased from 20% before 1996 to 76% after 1996. On pathologic analysis, 24% of specimens were T0. However, postoperative pathologic T stage had no effect on either recurrence or survival. Positive lymph node status predicted increased local recurrence and decreased survival. CONCLUSIONS: Neoadjuvant chemoradiation is safe, effective, and well tolerated. Postoperative lymph node status is the only independent predictor of recurrence and survival.

Adenocarcinoma↗
PubMed2001

Central corneal thickness measurement with a retinal optical coherence tomography device versus standard ultrasonic pachymetry.

PURPOSE: To demonstrate the capability of a standard, commercially available optical coherence tomography device (originally designed to measure retinal thickness) to image the human cornea in vivo and to measure central corneal thickness (CCT) in normal and edematous corneas. The intrapatient precision and interpatient variability of this novel application was compared to standard ultrasonic pachymetry. Also, the correlation of both methods was investigated. METHODS: CCT measurements using optical coherence tomography (OCT) and ultrasonic pachymetry (PACH) were obtained in 36 normal eyes and 16 eyes with corneal edema. RESULTS: Direct in vivo imaging of the cornea and measurements of CCT by OCT could be performed in all eyes. In normal subjects, CCT(OCT) was 530+/-32 microm and CCT(PACH) was 581+/-34 microm. The two methods showed a highly significant correlation with a standardized regression coefficient of 0.988. The difference between both methods was constant over the range of CCT (mean difference, 49.4+/-5.9 microm). The mean intrapatient SD of CCT measurements was 4.90 microm and 4.96 microm for OCT and PACH, respectively. In patients with corneal edema, mean CCT(OCT) was 601+/-59 microm, and mean CCT(PACH) was 667+/-68 microm. The difference between the two techniques increased slightly with increasing corneal edema (mean difference, 66.9+/-10.9 microm). CONCLUSION: Imaging of the human cornea can be performed by a standard retinal OCT device, and OCT measurement of CCT shows excellent correlation to values obtained by PACH, giving similar readings separated by a constant difference. In corneal edema, the difference between the two methods is additionally increased, but continues to demonstrate excellent consistency.

Adult↗
PubMed2001

Antibody response to Shiga toxins Stx2 and Stx1 in children with enteropathic hemolytic-uremic syndrome.

A Western blot (immunoblot) assay (WBA) for the detection of immunoglobulin G antibodies to Shiga toxins Stx2 and Stx1 in sera from 110 patients with enteropathic hemolytic-uremic syndrome (53 culture confirmed to have Shiga toxin-producing Escherichia coli [STEC] infection) and 110 age-matched controls was established by using a chemiluminescence detection system. Thirty-nine (74%) of the 53 culture-confirmed cases were infections with STEC serotype O157, and 14 (26%) were associated with infection by other STEC serotypes. The frequency of an anti-Stx2 response following infection by a Stx2-producing strain (34 of 48 cases; 71%) was higher than that of an anti-Stx1 response following Stx1-producing STEC infection (4 of 10). Furthermore, the frequency of an anti-Stx2 response in 110 control sera (10%) was significantly higher than the frequency of an anti-Stx1 response (1.8%) (P = 0.0325). For STEC O157 culture-confirmed cases WBA for toxin detection had a diagnostic sensitivity of 71% and a specificity of 90%. Because of its high specificity the assay might be a helpful tool for diagnosing suspected STEC infection when tests of stool samples or serological tests against various lipopolysaccharide antigens are negative. Furthermore, the prevalence of anti-Stx antibodies in healthy controls probably reflects the population immunity to systemic Stx-associated disease. It can thus serve as a basis for comparing immunity levels in different populations and for considering future Stx toxoid immunization strategies.

Adolescent↗
PubMed2001

Vitreoretinal surgery: pre-emptive analgesia.

AIM: Vitrectomies are performed either under general anesthesia (GA), local anesthesia (LA), or a combination of both. Postoperative pain is expected to be less in patients with LA because of prolonged action of the local anaesthetic. Pre-emptive analgesia is based on the idea that analgesia initiated before a nociceptive event will be more effective than analgesia commenced afterwards. The authors compared postoperative analgesia in patients with GA combined with preoperative or postoperative LA. METHODS: 90 patients scheduled for vitrectomy without buckling were enrolled in the study. 60 patients underwent GA, 30 without LA, 15 with preoperative LA, and 15 with postoperative LA. 30 patients received LA alone. Subjective postoperative pain was determined using the visual analogue scale. RESULTS: Postoperative pain was less under LA alone compared to GA alone (p < 0.0001). Additional preoperative application of LA resulted in less pain than additional postoperative application (p <0.05). Additional postoperative peribulbar aneasthesia did not differ from GA alone. CONCLUSION: The authors conclude that LA alone or preoperatively in addition to GA provides the best comfort for the patient in vitreoretinal surgery.

Adolescent↗
PubMed2000

Unfavorable response to cyclophosphamide in steroid-dependent nephrotic syndrome.

Development of steroid dependency represents a significant therapeutic challenge in steroid-sensitive nephrotic syndrome. Previous studies have shown conflicting results concerning the benefit of a 12-week treatment with cyclophosphamide (CPO), with 24%-67% of patients achieving long-term remission. We therefore analyzed the clinical response of 20 consecutive children with steroid-dependent nephrotic syndrome (SDNS) (12 male, median age at start of treatment 5.9 years, range 3.2-14.7 years) treated at our institution with CPO (2 mg/kg per day) for 12 weeks since 1989. Median duration of follow-up was 5.8 (range 1.1-9.25) years. Only 6 of 20 children (30%) showed a long-term remission of >2 years, while 14 of 20 (70%) developed relapses again. Of these, 12 patients (86%) again developed steroid dependency, requiring further alternative treatment. Our data show that a 12-week course of CPO leads to unfavorable results in the majority of patients with SDNS. We therefore conclude that there is a need for further optimization of therapy in SDNS.

Child↗
PubMed2000

[Iatrogenic colon perforation from the viewpoint of the surgeon. Experiences with 11 patients].

Iatrogenic colonic perforation is a rare but very dangerous complication of colonoscopy. We report on eleven prospectively recorded patients treated between 1994 and 1998. In seven cases the colonoscopy had been done for diagnostic and in four cases for therapeutic reason. Nine women and two men (age range 56 to 92 years) were affected. In 77% the perforation was found in the sigmoid colon. All patients were operated on and five sutures, five resections and one colostomy were performed. No significant differences could be shown in six patients with classical perforation compared with five patients presenting with prolonged abdominal pain. Only duration of symptoms was significantly different in the two groups. Three patients (85, 90 and 92 years) died from late complications.

Aged↗