Comparison of clinical effects between microscopic surgery and conventional surgery in children with penile hypospadias and difference analysis of postoperative urodynamics

Objective: To compare and analyze the clinical effects of microscopic surgery and conventional surgery in children with penile hypospadias and the differences in postoperative urodynamic indexes. Methods: It was a clinical comparative study. A total of 80 children with penile hypospadias admitted to Beijing Children’s Hospital Affiliated to Capital Medical University Baoding Hospital from July 2018 to September 2022 were selected and randomly divided into two group. The experimental group were treated with microscopic urethroplasty, while the control group were treated with traditional urethroplasty. The operative effect, operation time, total intraoperative blood loss, postoperative hospital stay and incidence of surgical complications were compared and analyzed between the two groups. All the children were followed up for two years, and the changes in urodynamic parameters including maximum urine flow rate (Qmax), average urine flow rate (Qavc), urine flow time (FT), peak time (TQmax) and residual urine (PVR) were compared before, two weeks after, six months after and two years after surgery. Results: The efficacy of the experimental group was significantly higher than that of the control group (p=0.013). The intraoperative blood loss and postoperative hospital stay in the experimental group were significantly better than those in the control group (p=0.000). The incidences of urinary leakage and urethral stricture in the experimental group were lower than those in the control group (p<0.05). The Qmax level in the experimental group was higher than that in the control group at six months and two years after surgery, while the FT level was lower than that of the control group (p<0.05). Conclusion: Microscopic surgery is a method with significant clinical value in the treatment of penile hypospadias.


INTRODUCTION
Hypospadias, one of the most common congenital abnormalities in males, 1 is characterized by ectopic urethral orifice, penile curvature and headscarflike changes of the dorsal foreskin. 2About 70% of children with hypospadias are penile. 3When repairing hypospadias, normal appearance and function are usually expected. 4A number of surgical approaches are available for hypospadias.At present, there are many kinds of urethroplasty applied clinically, but the general principle is to build a new urethra between the external urethra and the penis head and lay a multilayer tissue barrier between the new urethral canal and the skin to prevent urinary leakage. 5fter surgery on hypospadias, the most common postoperative complications include postoperative urinary fistula, urethral stricture, and unsatisfactory appearance.With the continuous development of science and technology, microsurgical techniques have achieved initial success in the repair of hypospadias.Microscopic techniques can be used to perform more precise tissue manipulations and clearly observe the direction of blood vessels, thereby ensuring good blood supply to the covering tissue, improving the success rate of surgery, and reducing the incidence of postoperative complications. 6n this study, the advantages of using microscopy in urethroplasty, the incidence of adverse reactions and postoperative complications were mainly evaluated, and the urodynamic parameters were used to make a comparative analysis between the microscopic surgery group and the conventional surgery group.Based on the changes in urodynamic indexes, we can provide a basis for early diagnosis and prediction of postoperative urethral stricture.

METHODS
It was a clinical comparative study.A total of 80 children with penile hypospadias admitted to Beijing Children's Hospital Affiliated to Capital Medical University Baoding Hospital from July 2018 to September 2022 were selected and randomly divided into two groups: the experimental group and control group, with 40 cases in each group.Patient data comes from the electronic medical record system in our hospital.Patients in the experimental group were treated with microscopic urethroplasty, while those in the control group were treated with traditional urethroplasty.No significant difference was observed in the comparison of the general data of the two groups (p>0.05), which was comparable (

Surgical methods:
Children in the experimental group were treated by microscopic surgery.All the children underwent surgery under general anesthesia.They were connected to a microscope surgical system, the head of the penis was fixed with 4-0 silk sutures with proper traction.A U-shaped incision was made below the urethral orifice.The size of the flap can keep the reconstructed urethra with a certain width.The foreskin was incised to Buck's fascia along 0.5cm below the coronary sulcus, and the skin and subcutaneous fascia were released to straighten the penis.With an appropriate indwelling silicone catheter, the urethral plate edge flap was sutured intermittently with 6-0 Vicryl suture under the microscope, starting from the proximal urethral orifice to the head of the penis.
The newly-built urethral opening tunneled through the penis head and was intermittently sutured at the normal urethral opening of the penis head, and the indwelled catheter in the new urethra was properly cut.Part of the tunica muscularis dorsalis of the penis was freed or an appropriate size of tunica vaginalis was taken, and the pedicle passed through the root of the scrotum and covered the newly-built urethra.After that, the dorsal foreskin was longitudinally cut and transferred to the ventral side to wrap around the penis, and the wound was closed and bandaged with sterile gauze.Children in the control group were operated by the traditional operation method, traditional surgical

RESULTS
The blood loss and postoperative hospital stay of the experimental group were significantly better than those of the control group (p=0.000)(Table-II).The effective rate of the experimental group was 97.50%, which was significantly higher than 80.00% of the control group (p=0.013)(Table-III).The incidences of urinary leakage (p=0.040) and urethral stricture (p=0.048) in the experimental group were lower than those in the control group, with a statistically significant difference (Table-IV).
Before surgery, no significant difference was observed in Qmax, PVR, Qavc, FT, and TQmax of the two groups (p>0.05).The Qmax level in the experimental group was higher than that in the control group at six months and two years after surgery, while the FT level was lower than that of the control group (p<0.05).Two years after surgery, the level of Qavc in the experimental group was higher than that in the control group, while the TQmax level was lower than that in the control group (p<0.05)(Table-V).

DISCUSSION
It was confirmed in our study the effective rate of the experimental group was significantly higher than that of the control group.The intraoperative blood loss and postoperative hospital stay in the experimental group were significantly better than those in the control group.The incidence of urinary leakage and urethral stricture in the experimental group were lower than those in the control group, with a statistically significant difference.The Qmax level in the experimental group was higher than that in the control group at six months and two years after surgery, while the FT level was lower than that of the control group.Two years after surgery, the level of Qavc in the experimental group was higher than that in the control group, while the TQmax level was lower than that in the control group.The conclusion of this study provides a new clinical reference for the treatment of penile hypospadias with microsurgery.
Conventional surgery in children with penile hypospadias Hypospadias, one of the most common congenital genital malformations in male children, often occurs in infants and young children. 9Clinically, orthopedic surgery is regarded as a gold standard in the treatment of hypospadias. 10In terms of the most common complications of hypospadias repair, urinary fistula, postoperative neourethral stricture and unsatisfactory appearance were prominent.
Especially urine leakage, repeated repair brings heavy financial burden and psychological pressure to the families of children 11 microscopic surgery is a rapidly developing surgical technique in recent years, which can enlarge tissues and blood vessels by corresponding times via a surgical microscope, providing clearer surgical vision and ensuring more precise operation. 12ble-V: Comparative analysis of urodynamic indexes between the two groups before and after surgery.Clinically, the anatomical structures involved in hypospadias surgery are limited to the penis and scrotum, small and subtle parts.For this reason, a well-illuminated and enlarged surgical field is essential for optimal outcomes. 13It was considered by Snodgrass et al. 14 that complete blood supply and local minor tissue injury are the key to reducing postoperative complications.El-Karamany et al. 15 concluded that microsurgical techniques could reduce postoperative pain, hospital stay and dressing change time, and even if a urethral stent was not used postoperatively, infants with distal hypospadias had a low complication rate without compromised shortterm functional and aesthetic outcomes.

Index
Urethral duct stenosis and urinary leakage are common complications after surgery for hypospadias, which can be attributed to inflammation, flap ischemia, scar healing, etc. Effective anti-inflammatory and prepuce skin or other grafts around the new urethral canal for repair may reduce the occurrence of urinary leakage. 16In most clinical studies, priority is given to how to increase the success rate of surgery.However, few studies have been carried out on how to reduce the corresponding risk after surgery, and how to early identify and timely manage urethral stricture.Uroflowmetry, as a simple and non-invasive method to detect asymptomatic urethral stricture, is crucial for evaluating the postoperative outcome of hypospadias surgery and for timely detection of urethral strictures. 17There is a certain inevitable relationship between abnormal urine flow and urethral stricture.
It is considered that 18 in 50% of hypospadias cases, abnormal urine flow is a risk warning of urethral stricture after surgery for hypospadias.Preoperative and postoperative urine flow assessment is of great significance.Qmax is a simple and effective method to evaluate urethral stricture. 19If the urine flow rate decreases, the possibility of urethral stricture should be suspected.Huang et al. 20 believed that the combination of measurement of residual urine and measurement of urine flow rate can really help to exclude the cause of urethral obstruction.Only when the urine flow rate is obviously reduced and the residual urine is obviously increased can the cause of obstruction be considered.On the contrary, low urine flow rate and residual urine are caused by abnormal bladder function.
Limitations: It includes a small sample size is included and the follow-up time is still short.Since the complications of hypospadias surgery are mostly late complications, it is particularly important to extend the follow-up time even to adulthood.In our future study, more cases will be included and the follow-up time will be extended, so as to further objectively evaluate the long-term effect and clinical significance of microscopic surgery for penile hypospadias.

CONCLUSION
Microscopic surgery is a method with significant clinical value in the treatment of penile hypospadias, boasting benefits such as a high efficacy, less bleeding, shorter hospital stays, lower incidence of postoperative complications, and significantly improved urodynamics compared to conventional surgery.

Table - I
: Comparative analysis of the general data of the two groups ( ) n=40.All the data in this study were statistically analyzed by SPSS 20.0 software, and the measurement data were expressed in ( ).Two independent samples t test was used to analyze the data between the experimental group and the control group.The c 2 test was used for rate comparison.P<0.05 indicates a statistically significant difference.
(2)The surgical effects: Markedly effective: All the symptoms of the children disappeared, and they could urinate on their own; Effective: children showed relieved symptoms and could stand to urinate after treatment, but had symptoms of pain and discomfort; Invalid: No improvement in the symptoms of the children.Total effective rate = (Markedly effective+effective)/total cases × 100% 8 ;Comparative analysis of surgical complications:Comparative analysis of urinary fistula, urethral stricture and unsatisfactory penile appearance after two weeks and six months after surgery; Changes of urodynamic indexes: The changes of urinary dynamic parameters including Qmax, Qavc, FT, TQmax and PVR were compared before, two weeks after, six months after and two years after surgery.Statistical analysis:

Table -
II: Comparative analysis of the surgical conditions of the two groups ( ) n=40.

Table -
IV: Comparative analysis of the incidence of complications between the two groups at 2 weeks and 6 months after surgery ( ) n=40.