Comparison of three novel biphasic scaffolds for one-stage treatment of osteochondral defects in a sheep model

In the last years, several tissue engineering techniques have been applied to develop different kinds of osteochondral substitutes to overcome the scarce reparative properties of this tissue. The aim of this study was to generate and compare three biphasic scaffolds in an osteochondral lesion in a large-animal model. A critical osteochondral defect was generated in the medial femoral condyle of 18 skeletally mature sheep. Three defects were left untreated, the remaining lesions were divided into three groups: 5 lesions were treated with a biphasic scaffold made of collagen type I and small cylinders of Magnesium Hydroxyapatite; 5 lesions were treated with a biphasic substituted formed by collagen type I and Wollastonite, 5 lesions were treated with a scaffold made of collagen type I and small cylinders of Wollastonite/Hydroxyapatite. Animals were sacrificed after 3 months and samples were analyzed by CT and MRI, macroscopic evaluation and histology. Our study demonstrated that one of these novel biphasic scaffolds possesses the potential for being applied for one-stage procedures for osteochondral defects.

Solubilization of homopolymers in a solution of diblock copolymers

We study theoretically mixed solutions of homopolymer and diblock copolymer chains. The solvent is a poor solvent for the homopolymers and a selective solvent for the copolymers. We find that the formation of copolymer micelles containing also the insoluble chains allows for an increased solubility of the homopolymers in the solution. In agreement with experiments, we find also that the solubilization power of the micelles, that is, the maximum amount of total homopolymer weight solubilized per unit weight of copolymers in solution, decreases strongly with the homopolymer index of polymerization.

Cinedefecographic findings in patients with obstructed defecation sindrome. A study in 420 cases

AIM

Obstructed defecation syndrome (ODS) represents a very common clinical problem. The aim of this study was to analyze the cinedefecographic findings in a group of patients with ODS.

METHODS

All patients with ODS were prospectively introduced into a database and underwent cinedefecography (CD). The grade of the syndrome was assessed by a new ODS score. The validated Agachan-Wexner Constipation Score System was also used. Four lateral films were taken during resting, squeeze, pushing and postevacuation phases and puborectalis length (PRL), anorectal angle (ARA) and perineal descent were recorded and analysed. The presence of an increased fixed perineal descent (FPD) and dynamic perineal descent (DPD), mucosal rectal prolapse (MRP), recto-rectal intussusception (RRI), recto-anal intussusception (RAI), rectocele (RE), enterocele (ET) and sigmoidocele (SG) were also evaluated.

RESULTS

Between February 2002 and March 2005, 420 patients, 404 (96.1%) females and 16 (3.8%) males with a mean age of 49+/-7.7 (range, 21-77) years, underwent CD. In 362 (86.2%) patients CD showed a combination of different cinedefecographic findings. RE, FPD and DPD in association with RAI or RRI were contemporary observed in 118 (26%) patients. MRP, RRI, FPD, RAI and RE were observed as singular finding in 21 (5%), 19 (4.5%), 12 (2.8%), 3 (0.7%) and 3 (0.7%) patients, respectively. In 6 (1.4%) patients a paradoxical contraction of the puborectalis muscle was observed.

CONCLUSIONS

CD shows that ODS is largely caused by multiple patterns of different abnormalities of the rectum and pelvic floor. Any treatment in symptomatic patients could be designed to treat multiple combinations of different abnormalities.

Pneumatic balloon dilatation for chronic anal fissure: a prospective, clinical, endosonographic, and manometric study

PURPOSE

Pneumatic balloon dilation has been shown to be effective in the management of chronic anal fissure, but its effect on the anal sphincter has not been fully investigated. The aim of this study was to evaluate prospectively the clinical, anatomic, and functional pattern in a group of patients treated by pneumatic balloon dilation.

METHODS

A series of 33 consecutive patients suffering from chronic anal fissure underwent pneumatic balloon dilation. Anal manometry and ultrasonography were performed prior to and 6 to 12 months after the treatment. Manometry was accomplished by means of an endoanal 40-mm balloon inflated with a pressure of 1.4 atmospheres that was left in situ for six minutes under local anesthesia. All patients were interviewed daily for three days after surgery and then clinically evaluated between the third and fifth postoperative weeks. Most patients were interviewed after 25.7 +/- 8.4 months (mean +/- standard deviation). Anal incontinence was evaluated by means of a validated score of 1 to 6.

RESULTS

The chronic anal fissure healed between the third and fifth weeks in 31 patients (94 percent), who became asymptomatic 2.5 +/- 1.4 days after pneumatic balloon dilation. None of them reported anal pain two years after the treatment (n = 20). The first post-pneumatic balloon dilation defecation was painless in 27 cases (82 percent). Two multiparous females (6 percent of the patients) complained of minor transient anal incontinence (score, 3). Chronic anal fissure recurred in one case (3 percent) after treatment. At manometry, the preoperative anal resting pressure decreased from 91 +/- 11.2 to 70.5 +/- 5.6 and to 78 +/- 5.7 mmHg, 6 and 12 months after pneumatic balloon dilation, respectively (P < 0.0001). Anal ultrasonography did not show any significant sphincter defect.

CONCLUSIONS

Pneumatic balloon dilation seems to be an effective, safe, easy procedure that decreases anal resting pressure without endosonographically detectable significant sphincter damage.

Management of colorectal emergencies: percutaneous abscess drainage

Pelvic abscesses represent the most frequent complications of colorectal surgery. Percutaneous CT or US guided drainage can be an alternative to surgical drainage that is associated to a significant mortality rate. In the current study results of PAD, performed in 39 patients with pelvic or abdominopelvic abscesses were reviewed in order to evaluate reliability of such procedure. Major part of the collections 33/39 (85%) developed after resective colorectal surgery, and 20/39 (51%) were associated to anastomotic fistula; 22/39 (56%) were poorly defined; 16/39 (41%) were multiloculated; 16/39 (41%) had a stool contamination, 23/39 (58%) were greater than 10 cm; 14/39 (35%) were multiple. Thirty-five patients (89.7%) healed, despite high number of complex abscesses and complete resolution of sepsis was achieved in 5.1 +/- 2.9 days. CT proved to be the most reliable tool in assessing distinctive features of collections as well as in identifying the best route for drainage. Adequate size of the catheter was essential to get an effective drainage. In particular, large sized catheter (> 20 Fr) had to be used to drain collections associated to anastomotic fistulas with stool contamination. In four elderly neoplastic patients with chronic illnesses (10%), only a single small sized catheter could be positioned, because of patients poor compliance and PAD was inaffective. Nevertheless even those patients got a partial resolution of the sepsis and their general conditions markedly improved, so that they were able to underwent successful surgical drainage. In conclusion PAD is a safe and reliable tool that can be employed as an alternative to surgical drainage at least as first measure, even if complex pelvic abscesses are found.