Sterilized Mosquito Net versus Commercial Mesh for Hernia Repair

BACKGROUND

In industrialized countries alloplastic meshes are routinely used for hernia repair. However, in developing countries they are rarely available or affordable. This study compares textile properties and tissue response of commercial polypropylene mesh (PM) vs. sterilized nylon mosquito net (MN).

METHODS

Textile properties were examined in vitro. In 12 goats one MN and one PM (5.5 x 8 cm) were implanted onto the posterior layer of the rectus sheath. Wound healing was clinically assessed. Histology was assessed after 4 or 16 weeks.

RESULTS

MN was thinner and lighter, but weaker than PM. All wounds healed without complications. After 16 weeks foreign body granulomas in the MN group contained a higher proportion of inflammatory tissue (32.7 vs. 22.1%) and more giant cells (3.1 vs. 1.7/10 granulomas) with a significantly lower partial volume of foreign body (23.2 vs. 36.9%). Partial volume of fibrotic tissue was similar. MN was 1,000-fold cheaper than PM.

CONCLUSIONS

PM was superior concerning strength and extent of inflammatory response. However, the findings indicate that MN might serve as a cheap substitute if an alloplastic mesh is needed but no commercial one is available or affordable. Further studies are justified which should include mosquito nets of different materials and long-term outcome.

Topoisomerase I expression in locally advanced rectal cancer as predictive marker for response to preoperative chemoradiation

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Background: In locally advanced rectal cancer combined modality treatment has become the standard therapeutical intervention. Preoperative downstaging is known as a predictor concerning lower local recurrence rate and probably better overall-survival. However, efficacy of neoadjuvant chemoradiation is compromised in some patients by so far unknown factors. The aim of the present study was to investigate topoisomerase I expression as a potential parameter for predicting response to irinotecan-based chemoradiation. Methods: 15 patients with rectal cancer clinical stages T3/4 Nx or N+ were recruited to receive weekly neoadjuvant irinotecan (1 hour before radiation) and capecitabine as well as cetuximab with a concurrent RT dose of 50.4 Gy (45+5.4 Gy). Surgery was scheduled 4–6 weeks after the completion of chemoradiation. Samples of normal and tumor tissues of all patients were collected before neoadjuvant treatment. Initially, RNA-oligonucleotid-array of three patients (one good responder and two non-responders) was accomplished to show qualitatively different gene expression. To quantify the differences, real-time PCR of topoisomerase I was performed. Results: The differences of gene expression in the RNA-oligonucletoidarray were correlated to the clinical response to neoadjuvant chemoradiation as topoisomerase I showed a significant higher expression in the tumor tissue of the good responder before treatment (p<0.0001). PCR-analysis showed a relatively higher median expression of topoisomerase I in normal tissue (1.7 vs. 0.9; p=0.85) and in tumor tissue (1.5 vs. 1.3; p=0.36) of the subsequent good responding patients (n=10). Conclusion: Patients respond differentially to chemoradiation in terms of clinical response and gene expression shifts. The oligonucleotidarray results leads us to assume that response may be predictable. The preliminary results of PCR demonstrate that TopoI expression describes a valuable parameter for prediction of efficiency of irinotecan in advanced rectal cancer. The small number of patients may have caused the missing of the statistical significance. We are intending an extension of the PCR analysis to more powerful series based on the achievements of the current investigation results.

No significant financial relationships to disclose.

A phase II study of capecitabine and irinotecan in combination with concurrent pelvic radiotherapy (CapIri-RT) as neoadjuvant treatment of locally advanced rectal cancer

We sought to evaluate the efficacy and safety data of a combination regimen using weekly irinotecan in combination with capecitabine and concurrent radiotherapy (CapIri-RT) as neoadjuvant treatment in rectal cancer in a phase-II trial. Patients with rectal cancer clinical stages T3/4 Nx or N+ were recruited to receive irinotecan (50 mg m⁻² weekly) and capecitabine (500 mg m⁻² bid days 1–38) with a concurrent RT dose of 50.4 Gy. Surgery was scheduled 4–6 weeks after the completion of chemoradiation. A total of 36 patients (median age 62 years; m/f: 27:9) including three patients with local recurrence were enclosed onto the trial. The median distance of the tumour from the anal verge was 5 cm. The main toxicity observed was (NCI-CTC grades 1/2/3/4 (n)): Anaemia 23/9/−/−; leucocytopenia 12/7/7/2, diarrhoea 13/15/4/−, nausea/vomiting 9/10/2/−, and increased activity of transaminases 3/3/1/−. One patient had a reversible episode of ventricular fibrillation during chemoradiation, most probably caused by capecitabine. The relative dose intensity was (median/mean (%)): irinotecan 95/91, capecitabine 100/92). Thirty-four patients underwent surgery (anterior resection n=25; abdomino-perineal resection n=6; Hartmann's procedure n=3). R0-resection was accomplished in all patients. Two patients died in the postoperative course from septic complications. Pathological complete remission was observed in five out of 34 resected patients (15%), and nine patients showed microfoci of residual tumour (26%). After a median follow-up of 28 months one patient had developed a local recurrence, and five patients distant metastases. Three-year overall survival for all patients with surgery (excluding three patients treated for local relapse or with primary metastatic disease) was 80%. In summary, preoperative chemoradiation with CapIri-RT exhibits promising efficacy whereas showing managable toxicity. The local recurrence and distant failure rates observed after a median 28 months are low compared with standard 5-fluorouracil based therapy.

Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection

BACKGROUND/AIM

Numerous new techniques have recently been reported and described for the endoscopic mucosal resection of large superficial lesions of the gastrointestinal tract. We present here for the first time the application of a water jet dissector for mucosa elevation.

MATERIALS AND METHODS

In an ex vivo study, the effectiveness of a water jet dissector (Helix Hydro-Jet) placed directly on the stomach walls of 8 pigs was examined to create a mucosal elevation. After having determined optimal pressures, angle of application, and application times, 13 submucosal fluid cushions were produced in different areas of the stomach walls of 8 pigs in vivo, and the sizes of the resulting submucosal cushions were measured.

RESULTS

Using pressures between 30 and 70 bar, it was routinely possible to create submucosal fluid cushions in the stomach wall ex vivo as well as in vivo. Histological examination showed a selective edema in the submucosa without damage to the deeper mucosal layers of the gastric wall.

CONCLUSIONS

The capacity of a targeted high-pressure water jet to penetrate the mucosa and selectively create a fluid cushion in the submucosa facilitates endoscopic resection of the mucosa. This new method could contribute to ameliorate the endoscopic treatment of mucosal tumors which previously could not be resected endoscopically due to their size, extent, or location.

Tumor suppressor Pdcd4 inhibits invasion/intravasation and regulates urokinase receptor (u-PAR) gene expression via Sp-transcription factors

Tumor suppressor Pdcd4 has recently been shown to inhibit invasion by activating activator protein-1 (AP-1); however, little is known of the functionally significant Pdcd4-target genes. The urokinase receptor (u-PAR) promotes invasion/metastasis, and is associated with poor cancer-patient survival. The present study was conducted (1) to investigate a role for Pdcd4 in intravasation, invasion and u-PAR regulation, and (2) to describe mechanisms by which this is achieved. Fourteen cell lines showed reciprocal expression of u-PAR/Pdcd4. Resected tumor/normal tissues of 29 colorectal cancer patients demonstrated a significant inverse correlation between Pdcd4/u-PAR. siRNA-Pdcd4-transfected GEO cells significantly increased endogenous u-PAR mRNA/protein. A u-PAR-promoter-chloramphenicol acetyl transferase (CAT)-reporter was reduced in activity with increasing Pdcd4 expression in RKO. Deletion of a putative Sp-1-binding site (-402/-350) inhibited u-PAR promoter regulation by Pdcd4, this being paralleled by a reduction of Sp1 binding to this region in pdcd4-transfected cells. Pdcd4-transfected cells showed an increase in Sp3 binding to u-PAR promoter region -152/-135, the deletion of which reduces the ability of Pdcd4 to suppress u-PAR promoter activity. Surprisingly, the u-PAR-AP-1 site was not targeted by Pdcd4. Finally, RKO cells overexpressing Pdcd4 showed an inhibition of invasion/intravasation (chicken embryo metastasis assay). These data suggest Pdcd4 as a new negative regulator of intravasation, and qas the invasion-related gene u-PAR. It is the first study to implicate Pdcd4 regulation of gene expression via Sp1/Sp3.

[Neoadjuvant treatment of rectal cancer: towards an individualised therapy]

Neoadjuvant radiation or chemoradiation followed by oncological resection is the current treatment of choice for locally advanced rectal cancer. Profound diagnostics are mandatory to stratify patients for neoadjuvant treatment or primary surgery. Here, magnetic resonance tomography most probably will become the standard modality due to its ability to predict involvement of the circumferential resection margin during surgery. While the initiation of chemoradiation in T4 rectal cancer and patients with distal tumours potentially undergoing sphincter-preserving surgery is unequivocal, the treatment of choice for the remaining patients is undecided. Here, short-term radiotherapy (5 x 5 Gy) competes with chemoradiation of different intensity. In surgical oncology, minimally invasive surgery of the rectum needs further evidence before it can be accepted as an equivalent. Finally, the increase in multimodality treatment will ultimately increase the incidence of late functional sequelae which, up to now, are underrepresented in most reports due to the priority of oncological results. Since responders to neoadjuvant treatment are the ones who benefit most from these therapies, research related to prediction of treatment response has a fundamental role.

Overexpression of a member of the pentraxin family (PTX3) in human soft tissue liposarcoma

A unique feature of human soft tissue liposarcoma is a stable (12;16)(q13;p11) translocation observed mainly in myxoid and roundcell liposarcomas. This translocation results in FUS/CHOP fusion transcripts with a corresponding oncogenic protein. We hypothesised that genes downstream of FUS/CHOP might serve as attractive candidates for novel tumour associated antigens. Among a panel of analysed genes, only pentraxin related gene (PTX3) demonstrated high expression in liposarcomas as compared to normal tissues. The analysis of RNA and protein expression demonstrated concordant results. However, the level of RNA and protein overexpression did not correlate in all cases. Finally, PTX3 expression was not related to presence of a FUS/CHOP fusion transcript within the liposarcoma tissues. PTX3 has been associated with adipocyte differentiation and now, additionally, is characterised by a markedly increased expression in human soft tissue liposarcoma. This finding mandates further research efforts to clarify the exact role of PTX3 in liposarcoma oncogenesis.

Ileus secondary to wireless capsule enteroscopy

Wireless capsule enteroscopy, being a novel, painless investigative technique, is reported to be significantly superior to push enteroscopy in its ability to find bleeding abnormalities in the small intestine. Here we report a case of acute jejunal obstruction following wireless capsule endoscopy. The patient had a 1-month history of gastrointestinal bleeding of unknown source. Further evaluation including gastroscopy and colonoscopy, angiography and computed tomography (angio-CT), and radio-labeled erythrocytes scan failed to reveal a source of bleeding. Therefore, wireless capsule enteroscopy was performed. Before capsule endoscopy, there was no clinical or imaging evidence of strictures or stenosis. At readmission it could be shown that there were two inflamed strictures of the small intestine. The capsule was detected at a stricture of the small intestine detected by abdominal ultrasonography and conventional computed tomography. The patient underwent a medical treatment with steroidal and other anti-inflammatory drugs for a total of 23 days and was discharged without complaints. Acute laparotomy after readmission with jejunal ileus proofed the capsule occluding two highly inflamed jejunal stenosis caused by Crohn disease. The present case demonstrates the potential for complications when wireless capsule enteroscopy is performed in the presence of intestinal strictures. Any history of inflammatory bowel disease, abdominal irradiation, cancer, obstruction, and abdominal surgery must be elicited in detail and may exclude the use of wireless capsule enteroscopy.

[Perianal and rectal impalement injuries]

Perianal impalement injuries with or without involvement of the anorectum are rare. Apart from a high variety of injury patterns, there is a multiplicity of diagnostic and therapeutic options. Causes of perianal impalement injury are gunshot, accidents, and medical treatment. The diagnostic work-up includes digital rectal examination followed by rectoscopy and flexible endoscopy under anaesthesia. We propose a new classification for primary extraperitoneal perianal impalement injuries in four stages in which the extension of sphincter and/or rectum injury is of crucial importance. Therapeutic aspects such as wound treatment, enterostomy, drains, and antibiotic treatment are discussed. The proposed classification encompasses recommendations for stage-adapted management and prognosis of these rare injuries.

Peritoneal cancer treatment with CYP2B1 transfected, microencapsulated cells and ifosfamide

The prognosis of peritoneal spread from gastrointestinal cancer and subsequent malignant ascites is poor, and current medical treatments available are mostly ineffective. Targeted chemotherapy with intraperitoneal prodrug activation may be a beneficial new approach. L293 cells were genetically modified to express the cytochrome P450 enzyme 2B1 under the control of a cytomegalovirus immediate early promoter. This CYP2B1 enzyme converts ifosfamide to its active cytotoxic compounds. The cells are encapsulated in a cellulose sulfate formulation (Capcell). Adult Balb/c mice were inoculated intraperitoneally with 1 x 10(6) colon 26 cancer cells, previously transfected with GFP to emit a stable green fluorescence, by injection into the left lower abdominal quadrant. Two or five day's later animals were randomly subjected to either i.p. treatment with ifosfamide alone or ifosfamide combined with microencapsulated CYP2B1-expressing cells. Peritoneal tumor volume and tumor viability were assessed 10 days after tumor inoculation by means of fluorescence microscopy, spectroscopy and histology. Early i.p. treatment with ifosfamide and CYP2B1 cells resulted in a complete response. Treatment starting on day 5 and single-drug treatment with ifosfamide resulted in a partial response. These results suggest that targeted i.p. chemotherapy using a combination of a prodrug and its converting enzyme may be a successful treatment strategy for peritoneal spread from colorectal cancer.

Fluorescence-guided minimally invasive parathyroidectomy: a novel detection technique for parathyroid glands

BACKGROUND

Detection of normal and pathologic parathyroid glands often is difficult because of their variability in number and location. The feasibility and efficacy of a fluorescence technique for identifying parathyroids have already been proved in an experimental setting. This is the first report of human fluorescence-guided parathyroidectomy.

METHODS

A 72-year-old man with primary hyperparathyroidism underwent minimally invasive videoscopically assisted parathyroidectomy after photosensitization with aminolevulinic acid. Under special fluorescence illumination by the D-light, a unilateral directed neck exploration was performed.

RESULTS

The enlarged adenoma and an atrophic parathyroid gland could be identified rapidly and removed because of their intense red fluorescence. Surrounding structures such as thyroid, muscles, and soft tissue remained nonfluorescent and could easily be distinguished from the parathyroid glands.

CONCLUSIONS

The aminolevulinic acid-induced fluorescence technique represents a convincing visual detection method for intraoperative identification of parathyroid glands. The technique serves as an additional tool requiring only moderate technical and clinical expenditure for help in guiding dissection down to a preoperatively localized adenoma. When used together with preoperative ultrasonography and sestamibi scan, the fluorescence technique may justify a unilateral, minimally invasive approach for selected patients.

Endoscopic full-thickness resection of the stomach: an experimental approach

BACKGROUND

Endoluminal endoscopic resections of the gastrointestinal (GI) tract have had increasing significance in recent years. Except for the extraperitoneal part of the rectum, endoscopic resections are restricted to the mucosal and submucosal layer to preserve the integrity of the GI tract wall.

METHODS

The SurgAssist is the first flexible stapling device consisting of a 2,000-mm-long flexible shaft and a stapling magazine that can be positioned intraluminally and used with a remote control. To prove the principle, we investigated the endoluminal application of an endoscopically assisted and intraluminally visualized full-thickness resection of the gastric wall in a pilot study of three pigs and a series of three human exenterates.

RESULTS

Full-thickness resection of the gastric wall in pigs can be performed with the SurgAssist flexible stapling device from an endoluminal access. However, due to the small lumen of the esophagus, the simultaneous transesophageal introduction of the stapler shaft and gastroscope is not possible in pigs. The same procedure in three human exenterates showed that the simultaneous introduction of the flexible stapler and a standard gastroscope could be achieved without damaging the esophageal wall. Full-thickness resections of up to 4 x 4 cm were carried out with the use of two or three stapler magazines. The resulting sutures were found to be airtight upon endoscopic inflation of the stomach.

CONCLUSION

The clinical use of the SurgAssist intraluminal stapling device for endoscopic full-thickness resection of the gastric wall seems applicable for lesions in suitable locations of the stomach. Gastrointestinal stroma tumors and T1 tumors of the lower gastric corpus and antrum region are possible indications.

Hand-assisted laparoscopic sigmoid resection for diverticular disease: 100 consecutive cases

BACKGROUND

Hand-assisted laparoscopic surgery (HALS) has been proposed as a useful alternative to conventional laparoscopic and open surgery. As compared with conventional laparoscopic surgery, it offers the advantages of tactile feedback, better exposure, and a shorter learning curve. There is increasing evidence that HALS retains the advantages of minimal-access surgery. The aim of this study was to analyze the feasibility as well as the short- and medium-term outcomes of HALS sigmoid resection for diverticular disease.

METHODS

The study included 100 consecutive patients between July 1999 and August 2004. Data were prospectively recorded. Follow-up evaluation was performed by standardized telephone interview after a mean postoperative period of 19 months (range, 2-55 months).

RESULTS

Two major intraoperative complications occurred: splenic laceration requiring splenectomy and ureteral injury requiring suture. There were only three conversions: one case of pararectal incision and two cases of extended lower Pfannestiel incision. There was no single case of conversion to midline laparotomy. One patient died postoperatively of myocardial infarction. The postoperative complications included intraabdominal hematoma (2%), anastomotic leakage (3%), wound infection (11%) and bladder dysfunction (1%). The reoperation rate was 5%. The median hospital stay was 8 days. In terms of satisfaction with the results, 97% of patients would choose HALS again.

CONCLUSIONS

When used for diverticular disease, HALS sigmoid resection has a low intra- and postoperative complication rate. The satisfaction rate among patients is high. Even in technically difficult cases, conversion to midline laparotomy can be avoided.

A new technique of endoscopic full-thickness resection using a flexible stapler

There is a significant need for a safe and easy technique for endoluminal endoscopic resection of gastrointestinal lesions, but such procedures are usually restricted to resection of the mucosal layer in order to preserve the integrity of the wall of the gastrointestinal tract. We present two patients, one with early cancer and one with a carcinoid tumor, who were treated by endoscopic full-thickness resection. We used a stapling device, consisting of a flexible shaft, which was positioned intraluminally, and a remote control. After pilot investigations in pigs and in human anatomical preparations, we performed a full-thickness resection of the gastric wall in these patients, using the flexible stapling device under gastroscopic control. Gastric wall specimens up to 4 cm x 4 cm in size were resected with the use of two to three stapler magazines. Both procedures followed an uneventful course and the patients made an uncomplicated recovery. Further studies are necessary to test the applicability of the technique in the management of other gastric neoplastic lesions.

Biodegradation of absorbable sutures in body fluids and pH buffers

OBJECTIVE

This study measures the influence of body fluids on the loss of tensile strength of absorbable sutures in vitro.

METHODS

Nine synthetic absorbable sutures were incubated in different gastrointestinal fluids, as well as in blood and three buffers. Stretch tests were performed after days 0, 7, 14, and 21.

RESULTS

Tensile strength varied from 18.5 to 32.8 N, and elasticity varied from 9.5 to 51% of the initial length. The influence of pH, blood, and gastric juice was negligible on all sutures except PDS II. Except for Monocryl, all sutures, especially Polysorb and Vicryl, lost tensile strength much faster in bile, jejunal and pancreatic juices than in the corresponding buffers.

CONCLUSION

The biodegradation of sutures varies greatly in different body fluids independent of differences in pH.

[Sonographic localisation procedures in hyperparathyroidism -- persistent hyperparathyroidism after removal of four parathyroid glands]

This case report will give an example for the necessity of performing an ultrasound examination of the neck before resection of the parathyroid glands. In end-stage renal failure a 38-year-old man developed secondary hyperparathyroidism (HPT). Four glands were removed. Two years later the patient revealed persisting HPT. At this point an ultrasound examination was performed and demonstrated a fifth parathyroid gland located inside the thyroid gland. The case illustrates the benefit of cervical ultrasound, even in cases of secondary hyperparathyroidism, prior to any cervical exploration.

Atraumatic intracutaneous skin closure with self-made fishing line suture compared to commercial thread

OBJECTIVE

The aim of this study was to prove, whether the intracutaneous skin closure with self made fishing line suture is equivalent to commercial sutures.

DESIGN

It was a randomised blinded animal study.

SETTING

The study was performed in December 2002 at the Muhimbili University College of Health Sciences in Dar-es-salaam.

SUBJECTS

Both German surgeons from Mannheim, and Tanzanian surgeons from Dar es salaam operated on nine one year old Tanzanian domestic sheep.

INTERVENTIONS

108 standardised cutaneous wounds on the backs of the animals were closed by intracutaneous sutures either with self produced fishing line suture or a commercial nylon suture (Ethilon).

MAIN OUTCOME MEASURES

The clinical and histological outcomes, as well as the costs of this self-made fishing line suture, with a commercial nylon thread were evaluated and compared.

RESULTS

There are no significant differences between the two sutures in histological or clinical findings, or in the reported ease of use by the surgeons. The cost of a self-produced atraumatic thread is US$ 0.12, less than one-twentieth of the cost of the commercial thread.

CONCLUSION

Self-made fishing nylon suture has characteristics and properties in sheep skin wounds comparable to commercial nylon suture. The advantage of the commercial thread is the guaranteed quality assurance. It is discussed whether this quality assurance justifies the large price difference, and whether the self-produced thread should be recommended to surgeons in countries where the costs of surgical material often remains an obstacle for life saving operations.