Behavior of galvanized steel tube subjected to web crippling

The details of a research study of galvanized steel tube under web crippling were presented. A total of 48 galvanized steel square hollow sections with different boundary conditions, loading conditions, bearing lengths and web slenderness were tested. The experimental scheme, failure modes, load-displacement curves and strain intensity distribution curves were also presented. The investigation was focused on the effects of loading condition, bearing length and slenderness on web crippling ultimate capacity, initial compressive stiffness and ductility of galvanized steel tube. The results show that web crippling ultimate capacity increases linearly with the increase of the bearing length under EOF and IOF loading condition. In the end-flange and ITF loading conditions, strain intensity of the centerline of web reaches the peak and decreases progressively from central web to flanges. Finite element models were developed to numerically simulate the tests in terms of failure modes and ultimate capacity. Web crippling strength of galvanized steel tube increases linearly with the increase of the ratio of the bearing length to web thickness and decrease of web slenderness. The effect of ratio of galvanized layer thickness to web thickness on web crippling strength is small. Based on the results of the parametric study, a number of calculation formulas proposed in this work can be successfully employed as a design rule for predicting web crippling ultimate capacity of galvanized steel tube under four loading and boundary conditions.

Appendicular Mucosal Tube Implant with Dartos Wrap Operation for Hypospadias

Aims and Objective: To develop a better operation for hypospadias patients with poor and bad quality urethral plate and damaged urethral plate as in hypospadias cripples. Materials and Methods: I operated 21 cases of hypospadias with Appendicular mucosal tube implant with Dartos wrap operation from 17/04/2017 to 03/03/2019, in Jawale Institute of pediatric Surgery, and that group was labeled as group A. 27 cases of hypospadias were operated in same time span with conventional techniques such as extended Snodgrass operation and Byar’s two-stage operation (group B), kept as control. 7 patients (33.33%) were cases of hypospadias cripples with multiple surgeries done in the past. 4 patients (9.52%) patients had congenital short urethra. Remaining 10 patients (50%) were fresh cases with no operation done in past but with bad and fibrotic urethral plate. The longest follow up was 3 years and the shortest of 1 year. Technique of Operation: Appendicectomy performed by open technique and the serosa of Appendix cut longitudinally and stripped off the mucosal tube. The proximal hypospadias opening sutured with the appendicular mucosal tube with 6 sutures of 5-0 Vicryl. Dartos fascia is raised from the scrotum wrapped over the tube and 8 - 10 interrupted stitches taken with 5-0 Vicryl. Glanuloplasty performed over it. Suprapubic diversion did and kept for 3 weeks postoperatively. Results: In group A, 3 patients developed fistula and only 1 (4.76%) required repair at the end of 6 weeks. 2 (9.52%) patients developed grade 3 infection and settled with conservative treatment. UFR was normal at the end of 12 weeks (12.85 Ml/sec. In group B, 11 patients developed fistula and 9 (33.33%) required repaired. 9 (33.33%) patients developed strictures and all of them required multiple urethral dilatation under GA. 7 (25.92%) patients developed meatal stenosis.UFR was badly reduced with average of 5.78 ML/Sec. Conclusion: The operation proves to be a much better option compared to the conventional for group A patients. We need a series with longer follow up and larger number of patients.

Tunneled tubularized bladder mucosal graft for long urethral reconstruction:is it a reliable option in selected complex cases in children and adolescents?

Aim:We analyzed the use of tubularized tunneled bladder mucosa graft(TBMG)and its application as a salvage procedure or as primary surgery for long urethroplasty in children and adolescents.Specific attention was given to a new method to harvest a long bladder mucosa graft through a minimal detrusotomy.Methods:We analyzed the files of 10 patients who underwent TBMG urethroplasty at median age of 105 months(range 20-195 months).The indications were perineal hypospadias cripple in two,masculinizing genitoplasty for ovotesticular Ovotesticular Disorder of Sex Development(DSD)in two,perineal hypospadias in four,duplicated urethra in one,and complications of circumcision in one.Staged reconstruction was performed in all patients.The first stage was removal of all fibrous tissues and efficient treatment of curvature and skin coverage.After a minimal delay of one year,a free bladder mucosa graft was harvested through a minimal detrusotomy and tubularized.Tunneling of the graft was proceeded from the perineal urethrostomy to the glans.Results:The graft was successfully harvested through the minimal detrusotomy approach for variable lengths of urethroplasty;the median length was 10.5 cm(range 8-16 cm).The median follow up was 61.7 months(range 18-160 months).TBMG was the last surgery with no redo in five cases(50%).Long stricture occurred in one case of primary perineal hypospadias and needed a redo staged surgery.Two patients performed self-dilatation for distal stenosis.Conclusion:The tunneled bladder mucosa tube graft technique represents a good alternative for a long urethroplasty in patients with a paucity of healthy skin.The minimal detrusotomy technique for graft retrieval may reduce graft harvesting morbidity.