Necessity and safety of primary closure of the patent processus vaginalis in laparoscopic orchiopexy: protocol for systematic review and meta-analysis

Abstract

Introduction

A patent processus vaginalis (PPV) is frequently observed during laparoscopic orchiopexy in infants with cryptorchidism. Nevertheless, the decision to primarily close the PPV following laparoscopic orchiopexy remains a subject of debate. This protocol therefore outlines the scope and methodology for a systematic review and meta-analysis that will synthesise the available evidence to evaluate the clinical outcomes associated with primary closure of the PPV after laparoscopic orchiopexy.

Methods and analysis

A systematic electronic literature search will be conducted across PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials (CENTRAL) and ClinicalTrials.gov to identify eligible studies published before 31 May 2026. The methodological quality of the included studies will be assessed using the Cochrane Risk of Bias V.2 tool for randomised trials and the Risk of Bias in Non-randomized Studies of Interventions tool for non-randomised studies. The primary outcomes will include postoperative inguinal hernia, testicular atrophy and testicular ascent. Secondary outcomes will comprise operative time, estimated blood loss, length of postoperative hospital stay and overall 30-day postoperative complications. The robustness of the findings will be evaluated through subgroup analyses and sensitivity analyses. All statistical analyses will be performed using Stata 19.0 and RevMan Web, with statistical significance defined as a two-sided p < 0.05. The certainty of the evidence will be evaluated following the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework.

Ethics and dissemination

Ethical approval for this study based solely on aggregated and anonymised data is not required. Findings will be disseminated through peer-reviewed journals, conferences and interactive dialogues in this research area.

PROSPERO registration number

CRD420261289759.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• A comprehensive literature search will be conducted across multiple electronic databases, including PubMed, Embase, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL), from inception to 31 May 2026 without language restrictions.

• Randomised controlled trials and cohort studies will be included and analysed separately to ensure robust statistical power and subsequential conclusions.

• The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be employed to assess the quality of evidence, thereby providing comprehensive references and recommendations to inform clinical decision-making and guideline development.

• The conclusions should be interpreted with caution due to the limited number and quality of included studies.

Introduction

Cryptorchidism, so-called as undescended testes, is one of the most common congenital malformations in male neonates.¹ The incidence of cryptorchidism varies and increases with decreasing gestational age, affecting up to 45% of preterm neonates.² After spontaneous descent within the first months of life, cryptorchidism still exists in approximately 1% of all full-term male infants at 1 year old.² Besides, abdominal wall defects, such as gastroschisis and omphalocele, prove to be associated with substantial occurrence of cryptorchidism.³ Ipsilateral patent processus vaginalis (PPV) was present in 37.5% of unilateral cryptorchidism, which was strongly associated with right-sided, viable and intra-abdominal testes.⁴

Associated with potential infertility and testicular malignancy, structural abnormalities and atrophy are common in the affected testicles.⁵ Therefore, treatment for cryptorchidism should be initiated at 6 months of age and completed by 12 months, or at the very latest, by 18 months.^{6 7} Actually, in-time surgical treatment leading to a scrotally positioned testis remains the mainstay of comprehensive cryptorchidism management.^{6 8} Traditional inguinal orchidopexy is a widely applied technique standard for palpable testes, in which the PPV needs to be dissected off the spermatic cord proximally at the level of the internal ring.⁹ An unidentified or inadequately repaired PPV was determined as a critical factor leading to failed orchidopexy.¹⁰

Due to obvious advantages including minimal invasion, thorough separation of the spermatic cord, maintenance of the anatomical integrity of the inguinal canal and simultaneous identification of an occult contralateral PPV, laparoscopic approach, rather than traditional inguinal orchidopexy, is recently recommended for high-positioned cryptorchidism.^{11 12} In the era of laparoscopic orchidopexy, however, there remain several controversies on whether to close the PPV or peritoneal defect.^{13 14} Besides longer operation time and steep learning curve, primary closure of the PPV after laparoscopic orchiopexy might be associated with increased risk of testicular ascent and atrophy.¹⁵ Furthermore, it is found that disconnection without ligation of a PPV is usually followed by spontaneous peritoneal scarring and complete closure of the internal inguinal ring.^{14 16}

In total, there is still controversy over the necessity and safety of primary closure of the PPV after laparoscopic orchiopexy. Therefore, the present systematic review and meta-analysis protocol aims to comprehensively amalgamate all available evidence to guide the clinical practice.

Methods and analysis

Study registration

The present meta-analysis protocol was prospectively registered at the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD420261289759; https://www.crd.york.ac.uk/PROSPERO/view/CRD420261289759) on 20 January 2026 and constructed in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) 2015 checklist.¹⁷ The study will officially commence on 1 June 2026 and is expected to be completed by 1 December 2026. Any deviations from this protocol will be noted in the final manuscript and updated on the PROSPERO. The main text of our forthcoming meta-analysis will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Cochrane Collaboration’s standardised methodology.^{18 19}

Study eligibility criteria

Elaborate eligibility criteria are constructed according to the PICOS description model (participants, intervention, controls, outcome measures and study design).²⁰

Types of participants (P)

Children who were diagnosed with previously untreated cryptorchidism (unilateral or bilateral, inguinal or intra-abdominal) and scheduled for laparoscopic orchiopexy will be included in this study. Exclusion criteria will be retractile testis, ectopic testis or iatrogenic cryptorchidism; history of orchiopexy; prior treatment with human chorionic gonadotropin or gonadotropin-releasing hormone and its analogues; presence of contralateral hydrocele or inguinal hernia at initial diagnosis.

Types of interventions (I)

Both single-stage and staged laparoscopic orchiopexy procedures, such as the Shehata technique or the staged Fowler–Stephens procedure, meet the inclusion criteria.^{21 22} The surgical procedures of laparoscopic orchiopexy included laparoscopic exploration, location of the cryptorchidism, separation of the spermatic cord, orchidolysis and orchidopexy. The primary closure of the peritoneum over the PPV was then performed using sutures via intra-abdominal approach or a hernia needle via percutaneous extracorporeal approach.

Types of controls (C)

The disconnection without ligation of a PPV was set as the control.

Types of outcomes (O)

The primary outcomes will focus on the occurrence of postoperative inguinal hernia, testicular atrophy, and testicular ascent. Testicular atrophy is defined as a testicular atrophy index exceeding 25% for the affected testis within postoperative 5-year follow-up.²³ The secondary outcomes will be operation time, blood loss volume, length of postoperative hospital stay and overall postoperative 30-day complications (Clavien–Dindo classification grade II or higher).²⁴

Types of study design (S)

Prospective randomised controlled trials (RCTs), quasi-RCTs (eg, alternate-day participants assignment) and cohort studies which reported at least one outcome of interest (OOI) will be included.

Information sources and search strategy

A systematic electronic literature surveillance will be performed across the PubMed, Embase (OVID interface), Scopus (via Elsevier) and Cochrane Central Register of Controlled Trials (CENTRAL) databases using keywords and medical subject headings (MeSH) related to “cryptorchidism” and “PPV” to acquire relevant studies published before 31 May 2026. Additionally, the reference lists of all included articles will be reviewed to confirm potential eligibility. Manual searching will also be conducted when necessary to supplement the electronic search results. To identify ongoing clinical trials, searches will also be conducted in the International Clinical Trials Registry Platform and ClinicalTrials.gov databases. The search will be restricted to studies involving human subjects. A detailed and specific search strategy, including the corresponding syntax for the PubMed database, has been developed (table 1).

Table 1. Search strategy for the PubMed.

Search	Search terms
#1	(cryptorchidism) OR (cryptorchism) OR (cryptorchid) OR (cryptorchidy) OR (undescended testes) OR (undescended testis) OR (undescended testicle*) OR (retained testes) OR (retained testis) OR (retained testicle*) OR (enorchismus) OR (enorchia)
#2	(orchiopex*) OR (orchidopex*) OR (cryptorchidopex*) OR (Fowler-Stephens) OR (Shehata)
#3	#1 OR #2
#4	(laparoscop*) OR (peritoneoscop*) OR (celioscop*) OR (minimally invasive)
#5	#3 AND #4
#6	(processus vaginalis) OR (process vaginalis) OR (vaginal process) OR (canalis inguinalis) OR (inguinal canal*) OR (canal inguinal) OR (spermatic canal) OR (inguinal ring*) OR (abdominal ring) OR (peritoneal defect)
#7	#5 AND #6
#8	animals [mh] NOT humans [mh]
#9	#7 NOT #8 Limits: Publication date through December 31, 2025

This search strategy will be modified as required for other electronic databases.

NA, NA.

Study selection and data management

The records retrieved through the search strategy will be collected and imported into Mendeley software (RELX Group, Amsterdam, Netherlands). Three reviewers (TY, WD and YH) will independently screen the titles and abstracts of the retrieved records according to the eligibility criteria. For studies identified as potentially eligible, full texts will be thoroughly reviewed. If multiple related reports are available for a single clinical trial, the most recent publication with the most comprehensive data will be selected for inclusion. If further information is required to determine eligibility, the corresponding authors of the studies will be contacted via email. Following the initial identification, the three reviewers will then reassess all full texts and document reasons for the exclusion of any records. Any disagreements among the reviewers during this process will be resolved through consultation with a senior author (ZC, QM and WY). A structured PRISMA 2020 flow diagram will be created to illustrate the study selection process (figure 1).

Figure 1. PRISMA 2020 flow diagram template of study selection. CENTRAL, the Cochrane Central Register of Controlled Trials; ICTRP, the International Clinical Trials Registry Platform; PPV, patent processus vaginalis; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Then, the review author pair (QM and JS) will extract the general characteristics from the selected articles using a customised electronic form for pooled analyses. The following dataset will be collected from all eligible studies: title, first author, year of publication, country, study design, study period, sample size, participant characteristics, surgical management of PPV and all OOIs. Additionally, corresponding authors will be contacted via email to request relevant raw data to ensure the accuracy of the meta-analysis. If no effective reply is received within 2 weeks, individual trials with missing data will be excluded from the pooled analyses of the OOIs. For high-quality management and synthesis, the cross-checked data will subsequently be entered into Stata 19.0 software (Stata Corp LLC, College Station, Texas, USA).

Risk of bias assessment

Two reviewers (TY and WD) will independently assess the methodological quality of the included studies. For RCTs, the Cochrane Risk of Bias V.2 (RoB 2) tool will be applied to evaluate bias across five domains: the randomisation process, deviations from intended interventions, missing outcome data, measurement of outcomes and selection of reported results.²⁵ The RoB 2 Excel Tool (available at https://www.riskofbias.info/welcome/rob-2-0-tool/current-version-of-rob-2) will be used to perform the assessment for primary outcomes.^{25 26} Evaluation will follow the criteria and guidance provided in the Cohrane Handbook for Systematic Reviews of Interventions.¹⁹ For non-randomised studies (NRSs), the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool will be employed.²⁷ In cases of discrepancy between the two reviewers, a third reviewer (ZC) will be engaged to be the arbitrator until a final consensus is reached. Given the potential risk of bias in the included studies, the findings of the future meta-analysis will be meticulously interpreted.

Data synthesis

Stata 19.0 and RevMan Web (The Cochrane Collaboration, Copenhagen, Denmark; available at https://revman.cochrane.org/info) will be used to conduct the future meta-analysis. For continuous outcomes (operation time, blood loss volume and length of postoperative hospital stay), pooled weighted mean differences or standardised mean differences with their respective 95% CIs will be calculated, depending on whether the measurement scales across studies are consistent. For dichotomous variables (the occurrence of postoperative inguinal hernia, testicular atrophy and testicular ascent, and overall postoperative 30-day complications), pooled ORs and corresponding 95% CIs will be computed. Statistical significance will be defined as a two-sided p < 0.05. To avoid large-sample NRSs dominating or reversing the pooled effect estimates, data synthesis will be performed separately for the RCT and NRS groups.

Statistical heterogeneity among studies will be assessed using the χ² test and quantified with the I² statistic. Substantial heterogeneity will be defined as I² > 50% and/or a p value < 0.10 for the χ² test. If substantial heterogeneity is present, a random-effects model will be applied; otherwise, a fixed-effects model will be used. To explore potential sources of substantial heterogeneity, leave-one-out sensitivity analyses and pre-specified subgroup analyses (intra-abdominal or inguinal cryptorchidism, single-stage or staged orchiopexy) will be performed. Whenever considerable clinical heterogeneity, a narrative review will be presented instead of a meta-analysis.

Publication bias

If over 10 studies are available, publication bias will be initially assessed through the visual inspection of a funnel plot’s symmetry.²⁸ Subsequently, statistical tests including Begg’s test and Egger’s test will be conducted, with a p-value <0.05 suggesting potential publication bias.^{29 30} When publication bias is identified, the ‘trim-and-fill method‘ will be applied to adjust for it.³¹

Confidence in cumulative evidence

The certainty of evidence will be systematically evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework.³² The quality of findings will be categorised as high, moderate, low or very low based on assessments across four domains: risk of bias, inconsistency, indirectness and imprecision.³³ A high-quality rating reflects substantial confidence in the estimated intervention effect. The GRADE assessments will be summarised in an evidence profile table.

Ethics and dissemination

The present systematic review and meta-analysis will not require ethical approval, as it is based solely on aggregated and anonymised data from previously published studies and doesn’t involve direct engagement with human participants. The complete findings of this study will be disseminated through publications in a peer-reviewed journal, presentations at national and international conferences and forums, and interactive dialogues with local community organisations in this research area.

Discussion

Currently, there remain several debates on the necessity and safety of primary closure of the PPV or the resulting peritoneal defect following laparoscopic orchiopexy.³⁴ First, the detection of the PPV during laparoscopy does not definitively predict subsequent development of an inguinal hernia or hydrocele.^{35 36} In most infants, a watch-and-wait approach for at least the first 12 months of life is justified due to the potential for spontaneous closure of the PPV.³⁷ Second, the key to any technique for managing the PPV lies in inducing localised peritoneal scar formation. Only disconnection or thermal injury without closure of the peritoneum over the PPV proved to be not associated with a significant increase of metachronous inguinal hernia or hydrocele.^{38 39} Finally, the laparoscopic closure of the PPV may be associated with a learning curve and could potentially prolong both operative and general anaesthesia time for infants with cryptorchidism.⁴⁰

Above all, this protocol is designed to conduct a systematic review and meta-analysis that synthesises existing evidence to assess the necessity and safety of primary PPV closure following laparoscopic orchiopexy. Furthermore, the meta-analysis will aim to identify subgroups of patients who are most likely to benefit from primary closure of the PPV, and to elucidate the clinical implications of the findings for guiding treatment decision-making. All methodological and statistical procedures will adhere to the PRISMA guidelines.¹⁸ Risk of bias will be evaluated at the study level using the Cochrane RoB 2 or ROBINS-I tool,^{25 27} and evidence certainty will be appraised at the outcome level using the GRADE approach.³²

Data availability statement

Data are available upon reasonable request.