Biomedical subjects

C Tonus

Publications and source records attributed to C Tonus.

6 recordsLinked to original sources

PubMed2000

Reconstruction and navigation system for intraoperative brachytherapy using the flab technique for colorectal tumor bed irradiation.

PURPOSE: To present the development of a new navigation and reconstruction system based on an electromagnetic free-hand tracker and on CT imaging for treatment planning of intraoperative high-dose-rate brachytherapy (IORT-HDRB) in the sacral region. Our aim is to improve accuracy and to enable individualized treatment planning and dose documentation to be performed for IORT-HDRB using a flab technique. METHODS AND MATERIALS: The material consists of an electromagnetic 3D tracker system, a PC workstation with Microsoft Windows NT 4.0 operating system, and a recognition program for continuous speech. In addition, we designed an external reference system constructed of titanium and Perspex, which is positioned in the pelvis, and a special digitizer pen for reconstruction of the flab geometry. The flab design incorporates a series of silicon 10-mm-diameter spherical pellets. Measurements were made with a pelvic phantom in order to study the accuracy of the system. The reconstruction results are stored and can be exported via network or floppy to our different treatment planning systems. RESULTS: Our results for the reconstruction of a flab with six catheters and a total of 100 spherical pellets give mean errors in the range (2.5 +/- 0.6) mm to (3.5 +/- 0.8) mm depending on the positions of the pelvic phantom and transmitter relative to the operation table. These errors are calculated by comparing the reconstruction results of our system with those using a CT-based reconstruction of the flab geometry. For the accuracy of the navigation system for the pelvic phantom, we obtained mean errors in the range (2.2 +/- 0.7) mm to (3. 1 +/- 1.0) mm. CONCLUSIONS: The new system we have developed enables navigation and reconstruction within the surgical environment with a clinically acceptable level of accuracy. It offers the possibility of individualized treatment planning and effective documentation of the 3D dose distribution in IORT-HDRB using a flab technique.

Brachytherapy↗

PubMed1999

[In Process Citation]

Intraoperative radiotherapy (IORT) is a new concept in the treatment of recurrent and primary advanced colorectal tumors. Between October 1994 and December 1997 27 patients (primary tumor: 8, first recurrent tumor: 12, second recurrent tumor: 7) received IORT (32 applications). Chemotherapy and percutaneous radiotherapy had already been given to all patients with advanced and recurrent colorectal tumors. The intraoperative irradiation was performed through HDR iridium afterloading. A flexible flab--individually adapted to the "tumor bed"--was used as applicator. The contact dose ranged from 10 to 15 Gy. The mean operation time (rectum resection: 5, rectum amputation: 14, debulking: 8) increased by 30 min on average. Eight patients had postoperative complications: perianal wound infections (3), sacrovesical fistulas (3), leakage of anastomosis (1) and neural ureter dysfunction (1). To date--on average 17.1 months (range: 3-33) after operation--13 patients are free of tumor recurrence or show stable disease. Ten patients--all of them had macroscopic residual tumor--have local tumor progression combined with good quality of life. Only 4 patients died (acute kidney failure, stroke, marasmus, systemic progression). The afterloading flab technique represents a technically simple, minimally harmful procedure in the therapy of colorectal tumor. Even when IORT with electrons is not feasible or the patients have already been irradiated, a higher radiation dose is possible. Given the demonstrated rate of local tumor recurrence, the afterloading flab technique seems to be a valuable treatment alternative to extended, high-risk resections. Long-term follow-ups will be necessary.

Journal Article↗

PubMed1996

[Colorectal carcinoma. Which factors are decisive for development of postoperative complications?].

This retrospective study analyses the prognostic effect of different factors on morbidity and lethality based on selected, primarily resecting colon carcinoma operations (n = 222). In all, 12.2% of our operations were performed under emergency conditions. The total complication rate was 31.5%, the lethality rate 7.7%. The left hemicolectomy cases showed the highest morbidity (48.4%), the rectum amputation the highest lethality (11.8%). Tumour staging tumour differentiation and the sex of the patient showed no significant influence on the postoperative morbidity and lethality. However, a correlation was proved between the age of the patient, tumour localisation, co-morbidity, duration of operation and the conditions under which the operation was performed (emergency or elective), on the one hand, and morbidity and lethality on the other.

Adult↗

PubMed1996

[Mechanical duodenal stump suture. Report of experiences: metal staples versus resorbable staples].

The main observation criterion of the present retrospective study is the insufficiency rate after machine closing of the duodenal stump (TA-clip seam device, Auto-Suture), as a consequence of gastrectomy, resection of the stomach with Billroth II respective Roux-Y reconstruction, depending on the used type of clip. Between January 1, 1985 and October 2, 1989 the closing of the duodenal stump was routinely carried out with metal clips (n = 253) in the City Hospital Offenbach. Between October 3, 1989 and December 31, 1991 polysorb staples (n = 96) were exclusively used. The patient collectives were comparable regarding age, sex, health status, basic diseases, accompanying diseases and surgical methods. Closing of the duodenal stump by polysorb staples demonstrated with 13.5% more dehiscent seams than with metal clips (4.7%). As a result of the present study, we cannot recommend the use of polysorb clips for the closing of the duodenal stump.

Adolescent↗

PubMedDate not supplied

Clinical relevance of tumor ploidy and micronucleus formation for oral cavity cancer.

AIMS AND BACKGROUND: To study the clinical relevance of tumor ploidy and micronucleus formation as prognostic factors. METHODS AND STUDY DESIGN: Twenty-eight patients with squamous cell carcinoma of the oral cavity were treated with primary radiochemotherapy consisting of irradiation up to 70 Gy in combination with cisplatin. Cell cycle distribution, micronucleus formation and ploidy were evaluated by flow cytometry of biopsies taken before treatment and after irradiation to 10 Gy (5x2 Gy). Sexteen out of 28 patients relapsed after a minimum follow-up period of two years. RESULTS: Flow cytometry of the recurrence biopsy showed hyperpentaploid (5c exceeding) cells in 13/16 (81%) of the relapsed patients. In 7 patients the hyperploid clone was not present in the flow cytometry of the primary tumors. Ploidy could retrospectively be determined also by image cytometry in archival tumor material of the pretreatment specimens. Patients with a level below 100 5c cells per 10,000 cell nuclei were shown to have a significantly better prognosis than patients with more than 100 hyperpentaploid tumor cells. The micronucleus formation was 2-5 times higher in tumors showing a good response to treatment than in carcinomas relapsing within two years. CONCLUSIONS: The 5c-exceeding ratio measured by image cytometry and micronucleus formation proved to be good prognostic parameters for the clinical outcome of patients with locally advanced head and neck carcinomas.

Chemotherapy, Adjuvant↗

PubMedDate not supplied

Introduction of proton pump inhibitors--consequences for surgical treatment of peptic ulcer.

BACKGROUND/AIMS: This retrospective study analyzes the influence of different factors on morbidity and mortality after surgical treatment of peptic ulcer. METHODOLOGY: At the Municipal Hospital of Offenbach, Germany, from 1985-1996, 485 patients underwent surgery. RESULTS: Of the 485 patients, 70.7% (343) were diagnosed to have duodenal ulcer and 29.2% (142) had suffered from gastric ulcer. During this period, 79.2% (384) of the operations were performed under emergency conditions because of acute complications (56% of these with perforation, 20% with penetration, 24% with ulcer bleeding), whereas the rest was done electively. Two hundred and ninety-one (60%) patients were male, the average age was 59 years and 71.7% (348) of the patients had certain concomitant diseases. We observed complications in 48% of the cases with a total postoperative mortality of 21%. CONCLUSIONS: Between 1985 and 1996 the total number of ulcer surgeries performed at the Municipal Hospital Offenbach per year has stayed almost constant. However, a definite increase of acute operations in addition to a decrease of elective interventions was noticed. The dissatisfying results of surgical treatment of peptic ulcer after the introduction of proton pump inhibitors seems to be the consequence of the negative selection of patients mentioned above. A connection could be proved between the age and condition of the patient, the type of the surgical intervention (acute or elective) and the morbidity and mortality after the surgery.

Adolescent↗