Biomedical subjects

H Till

Publications and source records attributed to H Till.

At least 19 recordsLinked to original sources

PubMed2006

Comparison of different training models for laparoscopic surgery in neonates and small infants.

BACKGROUND: Minimally invasive surgery in small children and infants requires special skills and training. This experimental study compares the efficiency of an in vitro pelvic trainer (PT) and an a in vivo animal model (AM). METHODS: For this study, 12 residents were prospectively randomized into two groups. Initially, all had to pass a basic skill assessment (3 tasks). Then endoscopic small bowel biopsy was performed (8 times) either with the in vitro PT (group A) or the in vivo AM (group B). Finally, all had to demonstrate this procedure in the in vivo AM and repeat the basic skill assessment. A quality index (complications, suture, biopsy) was evaluated. RESULTS: Initially, there was no difference between the two groups. Interestingly, the mean regression gradient of the index for the in vitro PT (group A) was significantly better than for the in vivo AM (group B). In the final in vivo operation, however, the mean index for the in vitro PT (group A) worsened significantly, whereas it increased for the in vivo AM (group B) (p = 0.037). CONCLUSION: Adequate training for an isolated mechanical task such as gut biopsy can be supplied using a pelvic trainer or animal model with similar effects. However in vivo performance of the same task requires secondary surgical skills, which are conveyed during live training with greater success. Consequently, stepwise teaching with both modules seems reasonable before these procedures are approached in neonates or small children.

Adult↗

PubMed2006

Is the anorectal sphincter damaged during a transanal endorectal pull-through (TERPT) for Hirschsprung's disease? A 3-dimensional, vector manometric investigation.

BACKGROUND/PURPOSE: The transanal endorectal pull-through technique (TERPT) for Hirschsprung's disease (HD) exercises considerable traction on the anorectal tissue during dissection. So the question arises as to whether TERPT impairs the integrity of the anorectal sphincter. Computerised 8-channel vector manometry allows a segmental, 360 degrees analysis of muscular defects along the anal canal. Such data after TERPT are not available yet. METHODS: Between 2002 and 2004, 7 children underwent primary TERPT for HD of the rectosigmoid. All could be recruited for follow-up examinations. Stooling pattern, rectal examination, conventional 4-channel and computerised 8-channel vector manometry were assessed; the anal sphincter pressure at rest (ASPR), rectoanal inhibitory reflex (RIR), anal canal length (ACL), high pressure zone (HPZ), maximal segmental pressure (max SP), segmental/total asymmetric index (SAI/TAI), vector volume at rest (VV) were studied. Mean pre- and postoperative values were compared (pre/post). RESULTS: After a mean of 14 months (range 3-21 months) all children had spontaneous bowel movements, with no complaints of encopresis or constipation. 4-channel manometry revealed an unchanged ASPR (48.1/49.2 mmHg). RIR was present in 1/7. Computerised 8-channel comparison revealed no changes for ACL (15.4/16 mm), HPZ (60/53.19 % of ACL), SAI (17.6/18.63 %) and TAI (35.8/35.63 %). A postoperative increase was noted for max SP squeeze (141.4/178.7 mmHg) and VV (38 161/46 680 mmHg/cm (2)). In conclusion, the TERPT for HD preserves the functional integrity of the anorectal sphincter complex and has a favourable clinical and manometric outcome.

Anal Canal↗

PubMed2006

Tumor model for laparoscopy in pediatric oncology: subperitoneal inoculation of human hepatoblastoma cells in nude rats.

BACKGROUND: Minimally invasive surgery (MIS) for diagnostic or even ablative purposes in pediatric oncology is gradually evolving, but little is known about its biological consequences and surgical complications. Especially for hepatoblastoma (HB), no study on the influence of laparoscopy is available yet. A special tumor model could facilitate a variety of investigations. The present study introduces a laparoscopic technique to create subperitoneal metastases of human HB. METHODS: 7 immuno-incompetent (rnu/rnu) rats (mean weight 198 g) received a stab incision in the lower abdomen to insert a 4 mm scope. Under laparoscopic guidance (CO2 pressure of 1 mmHg, flow of 0.2 l/min) an 18 G needle was introduced, to inject several subperitoneal deposits of the tumor cell suspension (HuH6, 3 x 10 (6) in 1 ml of RPMI-1640 medium). Tumor growth was allowed for 6 - 7 weeks and finally the animals were laparoscopically evaluated for peritoneal metastases. Each suspicious lesion was harvested for histology. RESULTS: One animal was investigated after 6 weeks without evidence of tumor growth. After 7 weeks, in 4 out of 6 animals at least one lesion could be detected. Histology revealed HB in all specimens. CONCLUSION: Subperitoneal inoculation of human HB cells in nude rats achieves intraabdominal tumor growth. The present model allows a variety of laparoscopic strategies and their oncological impact to be studied. Thus it may contribute to the development of distinct oncological concepts for MIS in children with HB.

Animals↗

PubMed2005

Videoscopic fluorescence diagnosis of peritoneal and thoracic metastases from human hepatoblastoma in nude rats.

BACKGROUND: Various medical disciplines are employing photodynamic diagnosis (PDD) when searching for malignancies. It is still unknown whether pediatric solid tumors such as hepatoblastoma are susceptible to this technique as well. METHODS: Human hepatoblastoma cells were injected into the abdomen or right thoracic cavity of nude rats. Tumor growth was allowed for 7 weeks. Then, photosensitization was induced by peritoneal lavage with 5-aminolevulinic acid (ALA). Applying the Storz PDD system and one 4-mm scope, all animals were investigated by videoscopic white light diagnosis (WD) and PDD. Suspicious lesions were marked and analyzed by spectrometry and histology. RESULTS: Positive fluorescence was documented for every tumor seen by WD in the abdomen or right thoracic cavity. Spectrometry of lesions showed a 6.34-fold increased fluorescence intensity. Histology revealed hepatoblastoma in all specimens. CONCLUSIONS: Human hepatoblastoma can be detected by PDD in a rat model. Considering the clinical success of this method in other specialties, our findings indicate that further investigations to evaluate the benefit of PDD for children with hepatoblastoma should be performed.

Animals↗

PubMed2005

Advanced paediatric laparoscopic surgery: repetitive training in a rabbit model provides superior skills for live operations.

TOPIC: The rapid development of advanced laparoscopic techniques is a strong challenge for the skills and competence of the paediatric surgeon. It is therefore mandatory that training must offer adequate preparation. The present experimental study investigates how surgical residents perform laparoscopic bowel biopsy and defect repair after training with a pelvitrainer versus a rabbit model. METHODS: New Zealand white rabbits, 3 mm instruments, a 5 mm scope and a 6 - 0 prolene suture were used. Twelve surgical residents were randomised into two groups. Their basic task was to take a seromuscular bowel biopsy laparoscopically and to repair the defect using an intracorporeal suture. Group I trained 8 times (on 8 occasions) with a pelvitrainer (PT), group II trained similarly using a rabbit model (RM). Each participant took a final test to demonstrate the operation in the rabbit. Operating time, suture time and perforation of the bowel were analysed. RESULTS: In the PT group, mean operating times decreased from 11.18 (+/- 5.04) min to 4.91 (+/- 0.89) min (p < 0.01), however the final test procedure in the rabbit model lasted 9.62 (+/- 5.11) min. In the RM group mean operating times also decreased from 10.04 (+/- 3.39) min to 6.38 (+/- 1.40) min (p < 0.01) during the eight training operations. Within this group the final live operation lasted 5.45 (+/- 0.67) min and was significantly faster than in the PT group 9.62 (+/- 5.11) min (p < 0.1). The suture times showed a similar pattern. A significant difference with respect to the rate of perforation was not found. CONCLUSIONS: Repetitive training in the rabbit provides superior skills for live operations. In paediatric surgical centres with advanced laparoscopic procedures, an animal model should be considered as an important step in training which may contribute to a beneficial outcome in patients.

Animals↗

PubMed2005

Functional imaging for determination of nephroblastoma: an obligatory diagnostic program.

In Europe, 1.7 % of children with predicted nephroblastoma undergo neoadjuvant chemotherapy without being correctly diagnosed. It is necessary to reduce the number of misdiagnoses. In a girl who was referred to our institute with the diagnosis of nephroblastoma of the right kidney, DMSA scan revealed a hypertrophic compensation of the contralateral nephropathy in the lower part. Functional imaging studies of the kidney should be performed in patients in whom the type of pathology of a suspect mass in the kidney region is unclear, including a careful scrutiny of the MRI scan.

Child↗

PubMed2005

Juvenile granulosa cell tumour (JGCT) of the ovary in a 6-year-old girl: laparoscopic resection achieves long-term oncological success.

Juvenile granulosa cell tumours (JGCT) represent a rare malignancy in childhood and their laparoscopic resection has not been advocated yet. We report on a 6-year-old girl with signs of precocious pseudo-puberty and an abdominal tumour. Work-up revealed premature thelarche, vaginal discharge, elevated estrogen levels, and a solid tumour in the lower pelvis (6 x 4 x 3 cm in MRI). The girl underwent laparoscopy (3 ports, 5-mm instruments), during which a non-invasive, mobile tumour of the left ovary was found. Since all margins of resection could be clearly identified, salpingo-oophrectomy was performed, using the harmonic scalpel for dissection and 5-mm clips to ligate the fallopian tube. Histopathology revealed a JGCT with an intact capsule (FIGO 1 a) which required no further chemotherapy. Within 3 months postoperatively the girl's signs of precocious puberty had resolved and at present, after a follow-up of more than 3 years, there is no evidence of tumour recurrence. Minimally invasive surgery of solid ovarian tumours in children remains controversial. However in the present case, laparoscopic resection did not compromise the surgical and oncological safety.

Abdominal Pain↗

PubMed2004

Partial laparoscopic decapsulation of congenital splenic cysts. A medium-term evaluation proves the efficiency in children.

BACKGROUND: In children, laparoscopic decapsulation of large congenital splenic cysts has occasionally been advocated, but substantial series focusing on its long-term success are still lacking. We report the follow-up experiences from two pediatric surgical centers. METHODS: The decision to proceed to surgery was based on patient symptoms and cyst size (>4 cm and/or progression), after strictly exclusion of a parasitic cause (by serology and CT scan). With the use of three ports (5-10-mm) and a Harmonic Scalpel, the epithelial portion of the cyst was radically excised. The remaining hilar epithelium was coagulated carefully. After discharge, the children were examined regularly by ultrasound to detect recurrences. RESULTS: From 1998 until 2002, eight children (mean age, 11.1 years; range, 3.1-16.4) were treated for cysts ranging from 4 to 15 cm in diameter. All procedures were completed without significant intraoperative complications (no major bleeding, no conversions). The mean operating time was 75 min (range, 56-184). Postoperatively, one child developed a cystic remnant (2 cm), which remained unchanged during 30 months of observation. After a mean follow-up of 2.2 years (range, 13-38 months), none of the patients showed any evidence of recurrent growth, and all of them had healthy splenic remnants. CONCLUSION: Partial laparoscopic decapsulation is an advantageous approach to large splenic cysts in children, because it is effective, preserves splenic tissue, and provides good medium-term results.

Adolescent↗

PubMed2004

Conscious sedation: Off-label use of rectal S(+)-ketamine and midazolam for wound dressing changes in paediatric heat injuries.

BACKGROUND: Wound dressing changes after heat injuries expose the patient to repeated painful and frightening procedures in short intervals. Safe, adequate, and easily administered analgesia and sedation are required. The goal of this study was to evaluate the off-label use of rectally administered S(+)-ketamine and Midazolam by paediatric surgeons during repeated outpatient dressing changes for paediatric burns and scalding. PATIENTS AND METHODS: A total of 47 dressing changes of 30 children with I - IIa degrees burns were evaluated. Vital signs, side-effects, complications, anxiolysis, and analgesia were recorded during the procedure and for the following two hours. Patients were assessed by a discharge scoring system and an age-appropriate pain scoring system at regular intervals. Before discharge, parents were interviewed on their level of satisfaction with the protocol. RESULTS: Adequate sedation and analgesia was achieved in 44 procedures (94 %). No complications and, in particular, no compromise of breathing, ventilatory, and cardiovascular functions were recorded. The discharge scoring system indicated a return to baseline function 30 minutes after the procedure in all patients. The parents were generally very satisfied with the protocol. All children old enough to be questioned were found to have an anterograde amnesia for the duration of the procedure. CONCLUSION: Conscious sedation with rectally applied S(+)-ketamine and Midazolam allows safe and painless dressing changes after heat injuries in children.

Adjuvants, Anesthesia↗

PubMed2003

Recurrent intussusceptions in an infant that were terminated by laparoscopic ileocolonic pexie.

For children with ileocolic intussusceptions, laparoscopy has been proposed as an emergency intervention, but it has not been elaborated for elective prevention of recurrencies. We report about an infant who developed his first ileocolic intussusception at the age of 12 months. Radiologic devagination was successful, but had to be repeated for two consecutive recurrences within several days. Six months later, he presented with another episode of intussusception, which again was managed conservatively. At this time, preventive surgery seemed indicated. Diagnostic laparoscopy using three trocars and 5-mm instruments showed an insufficient closure of the ileocecal valve, allowing the surgeon easily to provoke an intussusception. Consequently, the distal ileum was attached to the ascending colon with several interrupted 3-0 sutures. The infants postoperative course was uneventful. Oral feeding was started immediately, and he could be discharged after 3 days. Within a follow-up period of 1 year, no evidence of intussusception was noted. We conclude that for children with recurrent episodes of intussusception, laparoscopic ileocolonic pexie presents a beneficial strategy for protective surgery.

Humans↗

PubMed2003

Does the transplantation process modify the immunogenicity of fetal adrenal grafts in rat?

The concept that fetal tissue transplants enjoy an immunologic privilege grounds on the primary immaturity of major histocompatibility complex (MHC) expression. However, experiences in human organ transplantation reveal that the immunogenicity of any graft could be modified by external factors such as ischemia. Consequently, the question arises, whether the process of transplantation modifies the immunogenicity of fetal grafts. In a syngeneic rat model (Lewis), fetal adrenal glands were transplanted into the greater omentum of adult hosts. After harvesting the grafts sequentially, the immunogenicity was evaluated by analyzing the expression and distribution of the MHC classes I and II and were compared with untreated organs of equivalent age. The untreated fetal adrenal gland depicted little immunogenicity. However, compared with age-matched untreated control organs, at 2 wk after transplantation, the grafts demonstrated an increased expression of MHC I and II, upregulated throughout the entire adrenal cortex. No signs of MHC-mediated rejection were found. The upregulation of MHC persisted until the eighth week after transplantation. At 3 months after transplantation the expression of MHC I and II returned to the normal pattern of untreated controls. As this study used a purely syngeneic model, the immunologic changes observed could not be induced by a graft vs. host incompatibility, instead they were caused by experimental factors. The expressions of MHC class I and II was increased at 2 wk, but these proteins did not induce a T-cell mediated rejection or cellular infiltration. In conclusion, these findings question the concept of an immunologic privilege of fetal tissue transplants. Instead, experimental factors may modify the tissue's primary immaturity of its MHC. Further investigations must evaluate, whether the increase in MHC expression will have an impact on the rejection of fetal adrenal grafts in allogeneic hosts.

Adrenal Glands↗

PubMed2003

Postpericardiotomy syndrome after minimally invasive pectus excavatum repair unresponsive to nonsteroidal anti-inflammatory treatment.

A 14-year-old boy developed postpericardiotomy syndrome after an otherwise uneventful minimally invasive pectus excavatum repair. Dyspnoea, chest pain, and pericardial effusion progressed despite nonsteroidal anti-inflammatory treatment. The symptoms rapidly resolved with intravenous methylprednisolone, and pericardiocentesis was thus avoided. This is the first report of postpericardiotomy syndrome after the Nuss procedure treated with systemic steroids.

Adolescent↗

PubMed2003

Ileoileal intussusception caused by a Ewing sarcoma tumour. An unusual case report.

Intussusception typically occurs in childhood, presenting with a well-known medical history and clinical symptoms. Pathologically, a "leading point" may be attributed to lymphadenomatosis, polyps, or a tumour. In older patients and adolescents, the diagnosis can be complicated due to the lower incidence and variable subacute symptoms. We report on an 18-year-old patient with increasing abdominal discomfort over several weeks. External diagnostics showed no pathological signs or were misinterpreted as a malfunction of intestinal motility. The patient experienced increasing colics, recurrent vomiting, dehydration and weight loss. Finally he was transferred to our paediatric surgical department and laparotomy had to be performed for the clinical and radiological signs of an ileus. An ileoilealic intussusception was found, caused by a small bowel tumour, which almost completely obstructed the intestinal lumen. It was resected and bowel continuity was re-established. Histopathology revealed a very rare, highly malignant mesenchymal Ewing sarcoma, infiltrating the complete bowel wall. After the postoperative course, the patient was transferred to our oncological department for chemotherapy. In older children or young adults, intestinal malignancies are extremely rare. Nevertheless, if these patients suffer from unspecific complaints of chronic intestinal obstruction, a tumour must be ruled out. A Ewing sarcoma may be responsible for an intussusception.

Adolescent↗

PubMed2002

Laparoscopic resection of a congenital liver cyst and simultaneous closure of a diaphragmatic defect in a 5-month-old infant.

Congenital liver cysts are an unusual finding and present a difficult diagnostic challenge. In a 5-month-old infant, routine echocardiography detected a cystic lesion (3 cm in diameter) just below the diaphragm. All conventional diagnostics, including magnetic resonance imaging (MRI), failed to clarify its etiology definitively. Moreover, a phrenic irregularity was suspected at the site of Morgagni. Finally, laparoscopy (5-mm scope and instruments) confirmed the diagnosis of a solitary liver cyst and a diaphragmatic defect. Using a Harmonic scalpel, the cyst was resected and the diaphragmatic defect was closed with interrupted nonabsorbable sutures. The patient's postoperative course was uneventful. Pathological analysis showed a true liver cyst with mesothelial lining and hepatic residues. Retrospective speculation suggests a common embryologic origin for both malformations. In conclusion, laparoscopy allowed final diagnosis and simultaneous treatment of an infant with the rare combination of a liver cyst and a diaphragmatic defect. To our knowledge, this case represents the first endosurgical experience of such a simultaneous procedure.

Cysts↗

PubMed2002

Organ-specific maturation of the major histocompatibility antigens in rats.

The essential role of major histocompatibility complex (MHC) class I and II in the process of rejection has been documented, and some studies suggest that fetal transplants could enjoy an organ-specific immunologic privilege. However, little is known as to when these antigens develop in fetal organs and which tissues mainly present them. This study investigated the dynamics of immunogenicity in the developing transplant organs of rats. The study focused on the classic transplant organs including lung, heart, liver, pancreas, intestine, and kidney. Fetal organs (14th and 20th day of gestation), organs at the 3rd, 7th, 10th, 14th and 28th days postpartum (pp), 2 and 3 months pp, and adult organs were taken and snap-frozen in liquid nitrogen. MHC expression was analyzed applying the APAAP technique on serial cryosections by two well-defined monoclonal antibodies (mAb) generated against rat MHC class I (Ox 18) and class II (Ox 6). Immunoreactivities were compared to those of different monoclonal markers against endothelial cells (HIS52, CD 31), histiocytes (ED 1, ED 2), dendritic cells (Ox-62), granulocytes (HIS48), B-cells (RLN-9D3), T-cells (Ox-52), CD 4 (Ox-35), CD 8 (Ox-8a), natural killer cells (10/78), and CD 45 (Ox-1, leukocyte common antigen). A non specific mAb (MR 12/53) served as a negative control. In all stages of organ maturation, MHC I expression was found predominantly on immunocompetent cells, endothelial cells, and certain parenchymal cells, whereas MHC II was almost entirely restricted to dendritic cells. In organ development, the onset of MHC I expression and the number of MHC II-positive cells varied in a time-dependent manner. However, between the 2nd and 3rd month pp the expression pattern was comparable to adult organs. The study indicates that each organ carries a variable immunologic burden, that matures heterogeneously. Consequently, the variable content of MHC I/II in organ maturation needs to be considered for any transplantation model.

Animals↗

PubMed2002

[Perioperative pain therapy. Deficiencies in children and adolescents].

Present studies reveal that postoperative pain management for children is still insufficient in Germany. This situation is not only caused by a lack of knowledge, but, mainly, by a deficiency of standardized protocols in the hospitals and the lack of administrative responsibility. This article describes a specific concept for postoperative pain management in children. It basically focuses on three main topics: prevention of pain, the algorithm for analgesic treatment and the evaluation of the efficiency of the treatment. The surgeon plays a central role in pain prevention. By intraoperative blocking of the peripheral nerves, he can achieve effective analgesia. Postoperatively, he prescribes a basic medication according to the procedure used and the surgical trauma. Its effectiveness must be measured routinely thereafter and, depending on the score, an individual pain medication should be added. Pain measurement in children requires the application of specific scales for each age group. The evaluation of this concept has revealed therapeutic success, broad acceptance and efficiency in ward use. However a long-term benefit can only be achieved when postoperative pain management is one of the essential duties of the surgeon and it is constantly monitored within a department.

Adolescent↗

PubMed2002

Minimally invasive repair of pectus excavatum--the Nuss procedure. A European multicentre experience.

Since the first description in 1998, the minimally invasive repair of pectus excavatum has gained increasing acceptance. The aim of this survey is to report on the experiences of eight European centres with this technique. 172 patients with a mean age of 15.1 (+/- 4.6) years were treated and evaluated, 35.5 % were symptomatic. 45.3 % of the patients had an asymmetric configuration of the chest, 74.3 % had a CT index above 3.25. Mean duration of the operative procedure was 76 minutes. Major complications, including dislocation of the bar or stabiliser, pneumonia, atelectasis, local infection, pleural and pericardial effusion and liver injury occurred in 11.1 % of the patients. Minor complications, such as self-resolving pneumothorax, atelectasis and subcutaneous emphysema were reported in another 8.1 %. Early cosmetic results were excellent or good in 81.5 %. Although the surgical procedure is simple, blood-sparing and short, consideration of some important technical details, proper patient selection and knowledge of the limitations is of vital importance. Long-term results are still lacking.

Adolescent↗

PubMed2001

Plasmodium falciparum pfcrt and pfmdr1 polymorphisms are associated with the pfdhfr N108 pyrimethamine-resistance mutation in isolates from Ghana.

The Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) T76 and multidrug resistance gene analogue (pfmdr1) Y86 mutations are associated with chloroquine(CQ)-resistance. In isolates from 172 pregnant women living in the area of Agogo, Ghana, pfcrt T76 was detected in 69% and pfmdr1 Y86 in 66%. Pfcrt T76 but not pfmdr1 Y86 was more prevalent in samples from women with residual CQ in urine or serum. Parasite densities and multiplicity of infection of pfmdr wild type but not of resistant isolates were reduced by CQ. Adjusted for CQ and pyrimethamine (PYR) in urine, the P. falciparum dihydrofolate reductase (pfdhfr) N108 mutation which confers PYR-resistance was 3.1 and 3 times, respectively, more likely to be detected in isolates containing pfcrt and pfmdr1 mutations than in those comprising wild type alleles. Pfcrt, pfmdr, and pfdhfr mutations are frequent in P. falciparum from this part of Ghana which may limit the choice of drugs for the prevention of malaria in pregnancy. The association of CQ- and PYR-resistance mutations independent of recent drug use could indicate accelerated development of resistance to structurally unrelated drugs. Alternatively, it may reflect selection of resistance in persisting infections due to no longer detectable drug pressure.

ATP-Binding Cassette Transporters↗