Laparoscopic Percutaneous Extraperitoneal Closure Research Articles

Causes of recurrence of paediatric inguinal hernia after single-port laparoscopic closure

PurposeThis paper explores the causes of paediatric inguinal hernia (PIH) recurrence after single-port laparoscopic percutaneous extraperitoneal closure (SPLPEC).MethodFrom January 2015 to December 2020, the clinical data of 3480 children with PIHs who underwent SPLPEC were retrospectively reviewed, including 644 children who underwent SPLPEC with a homemade single-hook hernia needle from January 2015 to December 2016 and 2836 children who underwent the SPLPEC with a double-hook hernia needle and hydrodissection from January 2017 to December 2020. There were 39 recurrences (including communicating hydrocele) during the 2–5 years of follow-up. The findings of redo-laparoscopy were recorded and correlated with the revised video of the first operation to analyse the causes of recurrence.ResultThirty-three males and 6 females experienced recurrence, and 8 patients had a unilateral communicating hydrocele. The median time to recurrence was 7.1 months (0–38). There were 20 cases (3.11%) in the single-hook group and 19 cases (0.67%) in the double-hook group. Based on laparoscopic findings, recurrence most probably resulted from multiple factors, including uneven tension of the ligation (10 cases), missing part of the peritoneum (14 cases), loose ligation (8 cases), broken knot (5 cases), and knot reaction (2 cases). All children who underwent repeat SPLPEC were cured by double ligations or reinforcement with medial umbilical ligament.ConclusionThe main cause of recurrence is improper ligation. Tension-free and complete PIH ligation are critical to the success of surgery, which requires avoiding the peritoneum skip area and the subcutaneous and muscular tissues. Redo-laparoscopic surgery was suitable for the treatment of recurrent inguinal hernia (RIH). For giant hernias, direct ligation of the internal ring incorporating the medial umbilical ligament (DIRIM) may be needed.

Invited commentary: The outcome of closure of inguinal hernia with laparoscopic percutaneous extraperitoneal closure in young adults.

Invited commentary: The outcome of closure of inguinal hernia with laparoscopic percutaneous extraperitoneal closure in young adults.

The outcome of closure of inguinal hernia with laparoscopic percutaneous extraperitoneal closure in young adults.

Hernioplasty is one of the most commonly performed surgeries. However, the optimal procedure for young adults has not been defined yet. Our study compared the outcomes of laparoscopic percutaneous extraperitoneal closure (LPEC) in young adults with outcomes in children. We retrospectively reviewed patients aged 0-30years who underwent LPEC. Data regarding age, sex, hernia type, surgical time, pre-intraoperative laterality, contralateral patent processus vaginalis (CPPV), and complications were analyzed. LPEC was performed on 2642 patients in our hospital. Of these, 51 patients were young adults (aged 15-30years). Asymptomatic CPPV in unilateral patients was frequent in the <15-year age group (50.2%) compared to the 15-30-year age group (15.9%). The median surgical time was shorter in the <15-year age group (19min, interquartile range [IQR]: 24-33) compared to that of the 15-30-year age group (33min, IQR: 23.3-40.8). This is the first report on the outcomes in young adult patients who underwent LPEC. The median surgical time was longer in the 15-30-year age group than in the <15-year age group. The median follow-up was 4.7years with no intra-postoperative complications, such as postoperative bleeding, infection, persistent pain, and recurrence. LPEC is an effective, cosmetic, and safe surgical treatment in young adults and children.

Surgical tricks of handling a needle and grasping forceps during laparoscopic percutaneous extraperitoneal closure (LPEC) for pediatric inguinal hernia.

Laparoscopic percutaneous extraperitoneal closure (LPEC) is an alternative to open repair for pediatric inguinal hernias; however, its application for boys remains controversial. In this study, we developed a technique to enhance the safety and feasibility of LPEC. In our technique, forceps are used to pull up the peritoneum ahead on the route, creating a space between the peritoneum and structures, including gonadal vessels and vas deferens. This potentially decreases the risk of perioperative injury of these structures. This technique also allows the needle to pass on the shortest course around the inguinal ring without crossing the vas deferens, possibly lowering the likelihood of injury and preventing excessively high ligation of the vaginalis process. Our technique diversifies the LPEC methods, thereby augmenting the feasibility and safety of the procedure.

Efficacy of a modified needle grasper for single-port laparoscopic hernia repair in children: a propensity score-matched analysis.

The advantage of using the single-port technique over the conventional two-port approach is uncertain. This study aimed to evaluate the outcomes of a single-port laparoscopic percutaneous extraperitoneal closure (SLPEC) using a modified needle grasper in children and compare the results to those of two-port laparoscopic percutaneous extraperitoneal closure (TLPEC). A retrospective cohort analysis of SLPEC and TLPEC surgery from February 2016 to June 2021 was conducted at our institution. Pediatric patients underwent SLPEC using the modified needle grasper to complete the high ligation of the hernia sac, while operations in the conventional two-port group only used regular laparoscopic instruments. A 1:1 propensity score matching (PSM) analysis was used to reduce selection bias. Of 1320 patients, 1169 were included in the single-port/two-port crude evaluation, with 930 in the PSM cohort (465 patients/arm). Among 1:1 matched patients, the operation time for single-port patients vs. two-port patients were 11.28 ± 3.98 vs. 15.47 ± 4.54min for unilateral repair and 16.86 ± 4.59 vs. 20.40 ± 4.29min for bilateral repair (p < .05). Cosmetic results did not differ between the SLPEC and TLPEC groups (0% vs. 0.7%, p = 0.249). The recurrence rates were comparable between the two groups (0.6% vs. 1.1%, p = 0.725). Moreover, the differences in surgical site infection (SSI), testicular atrophy, open conversion and postoperative hydrocele occurrence were insignificant between the two groups. In this cohort study, the modified needle grasper is a safe and feasible instrument for SLPEC, and SLPEC using the needle grasper has a shorter operation time than TLPEC.

The Ropivacaine Concentration Required for Ultrasound-Guided Rectus Sheath Block in Pediatric Patients Undergoing Single-Incision Laparoscopic Hernia Repair: A Sequential Allocation Dose-Finding Study.

The local anesthetic concentration required for ultrasound-guided rectus sheath block (RSB) in children remains unknown. Knowledge of appropriate ropivacaine concentration can help clinicians reduce local anesthetic toxicity risk when performing ultrasound-guided RSB in children. This study aimed to determine the appropriate ropivacaine concentration for ultrasound-guided RSB in children undergoing laparoscopic inguinal hernia repair. In this single-arm prospective study with an up-down sequential allocation design of binary response variables, 18 consecutive children aged 11 months to 7 years undergoing single-incision laparoscopic percutaneous extraperitoneal closure were assessed. Orotracheal intubation was performed without intravenous anesthesia or a neuromuscular relaxant. After intubation, ultrasound-guided RSB was performed with a ropivacaine dose of 0.30 ml/kg(0.15 ml/kgper side). Dixon's up-and-down method was used to determine the concentration, starting from 0.25% in 0.05% increments. Surgery commenced ≥15 min following RSB. Body movement or a 20% increase in heart rate or systolic blood pressure within 1 min of surgery initiation determined an unsuccessful RSB. The 95% effective concentration of ropivacaine needed for successful RSB was calculated using the probit test. The 95% effective concentration of ropivacaine needed for successful ultrasound-guided RSB was 0.31% (95% confidence interval, 0.25-7.29). The highest concentration of ropivacaine required for successful ultrasound-guided RSB in the group of patients in this study was 0.3%. The 95% effective concentration of ropivacaine (0.30 ml/kgtotal, 0.15 ml/kgper side) for ultrasound-guided RSB was 0.31% in children undergoing single-incision laparoscopic surgery under general anesthesia.

Successful diagnosis of Turner syndrome in a 1-year-old girl during laparoscopic percutaneous extraperitoneal closure

Successful diagnosis of Turner syndrome in a 1-year-old girl during laparoscopic percutaneous extraperitoneal closure

Reduction of recurrence by peritoneal thermal injury in laparoscopic percutaneous extraperitoneal closure of internal ring for inguinal hernia in children.

To evaluate the impact of peritoneal thermal injury (PTI) in the reduction of recurrence incidence in laparoscopic percutaneous extra-peritoneal closure of internal ring (LPEC) for pediatric inguinal hernia (PIH) in children. Medical records of patients undergoing LPEC for PIH at our center were reviewed and divided into 2 groups: Group A (period from June 2017 to December 2017)-without PTI and Group B (period from January 2018 to December 2018) with PTI. The surgical technique and the type of suture used for LPEC were the same for both groups. The outcomes of the two groups were analyzed and compared. 277 patients with 283 IHs in group A were compared to 376 patients with 389 IHs in group B. There were no significant differences between the two groups in terms of age, gender, uni- or bilateral hernia. At a median follow-up period of 48months, there was no hydrocele, suture granuloma, testicular atrophy, or iatrogenic cryptorchidism in both groups. The recurrence rate in group A was 6.4%, significantly higher than 1.8% in group B (p = 0.002). Our study showed that PTI in LPEC for PIH is safe and associated with a significant reduction of recurrence incidence.

Laparoscopic percutaneous closure of patent processus vaginalis without hydrocelectomy for childhood primary hydrocele.

To present our surgical technique and the outcome of single-incision laparoscopic percutaneous extraperitoneal closure (SILPEC) of patent processus vaginalis (PPV) without hydrocelectomy for childhood primary hydrocele (CPH). A prospective study was conducted on all cases of CPH treated with SILPEC at our center between June 2016 and December 2021. In our SILPEC procedure, PPV was closed extraperitoneally using a percutaneous needle with a wire lasso. No hydrocelectomy or fenestration of the hydrocele was performed. Percutaneous aspiration was performed when the hydrocele fluid could not be pushed back to the peritoneal cavity. 553 patients were enrolled, with a median age of 34months (range from 22months to 13years). Ipsilateral PPV was present in all cases. There were no intraoperative complications and no conversion. At follow-up 6-72months, recurrent hydrocele occurred in 0.36%, and subcutaneous stitch inflammatory reaction was noted in 0.7%. There was no case of testicular atrophy or iatrogenic cryptorchidism. Postoperative cosmesis was excellent as all patients were virtually scarless. Ipsilateral PPV was present in all cases of CPH in our series. Our technique of SILPEC of PPV without hydrocelectomy is feasible and safe, with excellent postoperative cosmesis in the management of CPH.

Is the use of antibiotic prophylaxis in pediatric laparoscopic inguinal hernia repair necessary?

PurposeThe use of surgical antibiotic prophylaxis (SAP) in pediatric laparoscopic inguinal hernia repair is controversial. The aim of this study was to evaluate the impact of SAP on the surgical site infection (SSI) rate after laparoscopic inguinal hernia repair in pediatric patients. MethodsWe conducted a retrospective review of pediatric patients who underwent laparoscopic inguinal hernia repair between January 2017 and June 2022. Patient characteristics, intraoperative characteristics, antibiotic use and SSI within 30 days after the operation were collected via chart reviews. All patients underwent laparoscopic percutaneous extraperitoneal closure. SSI was defined by the Centers for Disease Control and Prevention criteria. Fisher's exact test was used to determine the association between SAP and SSI. ResultsIn total, 365 patients were included in this study. Forty-nine percent (n = 179) received antibiotics, and 51% (n = 186) did not. There were five infection cases (1.4%) in this study. Two (1.1%) were in the SAP group and three (1.6%) were in the no SAP group (p = 1.0). All infections were superficial. There were no adverse events due to antibiotic use. ConclusionA low percentage of SSI after laparoscopic inguinal hernia repair in the pediatric population was found, with no significant difference between the SAP group and the no SAP group. Therefore, the routine use of SAP for pediatric inguinal laparoscopic inguinal hernia repair is not recommended.

Utility of an endoscopic image processing system for framing laparoscopic images using surgeon's gaze point and voice commands during laparoscopic percutaneous extraperitoneal closure of inguinal hernia in children.

In laparoscopic surgery, it is the assistant who manipulates the laparoscope and manages the field of view. To develop an endoscopic image processing system that can adjust laparoscopic images as intended by the surgeon without interrupting the surgical procedure. We developed a touchless user interface that displays a magnified image of the endoscope using information of the surgeon's gaze point acquired by an eye-tracking device and the surgeon's voice commands, and evaluated its usefulness during laparoscopic percutaneous extraperitoneal closure (LPEC) of pediatric inguinal hernia. LPEC was performed in 15 clinical cases of pediatric inguinal hernia using this system. In all cases, the internal inguinal ring could be ligated by digitally zooming and moving the endoscopic image by eye tracking and voice command while the scope was fixed. This new touchless user interface with eye tracking shows promise as a support system for laparoscopic surgery.

Needle consideration in umbilical two-port laparoscopic percutaneous extraperitoneal closure for patent processus vaginalis of children: hook-needle or forcep-needle

BackgroundAlthough umbilical two-port laparoscopic percutaneous extraperitoneal closure for the treatment of processus vaginalis patency of children has been verified to be safe and effective, the improvements of technical skills and instruments have been always on their ways. Recently, forcep-needle has begun to be used. In this study, we compared forcep-needle with hook-needle in this minimal invasive procedure for children suffered from hernia or hydrocele, with the aim to evaluate the instrumental convenience of the two needles.MethodsFrom July 2021 to May 2022, we begun to use hook-needle or forcep-needle in umbilical two-port laparoscopic percutaneous extraperitoneal closure for children suffered from hernia or hydrocele. The hook-needle group included nineteen children and the forcep-needle group included twenty-four ones. The data of the patients age, sex, side, operation time, postoperative hospital-stay, follow-up time, postoperative complications were evaluated. Common silk thread was used to encircle the internal ring preperitoneally.ResultsThere were no statistical differences between the two groups for the following items: age, sex, side, operation time, postoperative hospital-stay and postoperative complications (P > 0.05). The follow-up time of the hook-needle group was longer than that of the forcep-one (P = 0.0020). No open transfer happened for all the patients. One hydrocele boy in the hook-needle group reoccurred 1 month postoperatively due to the peritoneal broken. The single pole retreating of the hook-needle accompanied with chaotic movements, while for that of the forcep-needle, the double-arm retreating movements were more orderly. The outer surface of the forcep-needle was smooth without restrain, as for the hook-needle, an inlaid barb held the danger of brokening the peritoneum.ConclusionIn our preliminary experience of umbilical two-port laparoscopic percutaneous extraperitoneal closure using a hook-needle or a forcep-needle, in view of the instrumental convenience and safety, the double-arm and smooth outer surface designs of the forcep-needle contained more spatial orientation perceptions and safety.

Successful laparoscopic repair for reduction en masse of infantile inguinal hernia: a case report of this rare condition.

BackgroundReduction en masse (REM) is a rare condition following manual inguinal hernia (IH) reduction in which a hernia sac is reduced back into the preperitoneal space with a loop of the bowel incarcerated at the neck of the sac. It resembles successful manual reduction and may thus be overlooked easily. We herein report an infantile case of REM of an IH that was successfully treated laparoscopically.Case presentationA 10-month-old boy with a surgical history of bilateral open IH repair at 4 months old presented with a bulge in his left groin and vomiting. A left incarcerated recurrent IH was suspected, and manual reduction was performed. The hernia was apparently reduced successfully, but abdominal distention and vomiting persisted. He was admitted for further observation due to the symptoms. On day 2 after admission, abdominal X-ray showed extensive small bowel obstruction (SBO). Enhanced computed tomography (CT) revealed protrusion of the small bowel with a closed-loop in the left groin. A closed-loop SBO due to postoperative adhesion or an internal hernia was suspected. To assess the etiology of SBO, emergent laparoscopic exploration with hernia repair was planned. Laparoscopy revealed REM of the left incarcerated IH with a thickened peritoneum at the neck of the sac. Laparoscopic reduction was performed, and the incarcerated small bowel showed no signs of ischemia. The hernia sac was not associated with the previously ligated processes vaginalis, which had been closed by a previous Potts’ procedure. It was located at the inside of the processes vaginalis. The sac was successfully closed by laparoscopic percutaneous extraperitoneal closure procedures, and iliopubic tract repair was also performed via the previous inguinal incision. The postoperative course was uneventful.ConclusionPediatric IH is due to the patent processes vaginalis, and REM is extremely rare. Laparoscopic surgery for REM is a relatively common and useful approach for the diagnosis and treatment of adults. In our infantile case, the laparoscopic approach was similarly effective for both investigating the cause of SBO and performing high ligation of the sac for this rare condition with IH.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40792-022-01535-1.

Comparison of laparoscope-assisted single-needle laparoscopic percutaneous extraperitoneal closure versus open repair for pediatric inguinal hernia

BackgroundLaparoscopic-assisted repairs for pediatric inguinal hernia have gained gradual acceptance over the past decade. However, consensus about the optimal management is still lacking. The aim of this study is to compare outcomes of a modified laparoscope-assisted single-needle laparoscopic percutaneous extraperitoneal closure (LPEC) versus open repair of pediatric hernias/hydrocele in a single institution.Materials and methodsWe retrospectively reviewed the medical data of children who underwent laparoscope-assisted single-needle LPEC and open repair (OR) for inguinal hernia from 2014 to 2019. Data collection included demographics, laterality of hernia, surgical time and time to follow-up. We also reviewed and analyzed the evidence of recurrence, the incidence of metachronous contralateral inguinal hernia (MCIH), and other complications.ResultsIn our cohort, 961 patients in the OR group and 1098 patients in the LPEC group were analyzed retrospectively. Mean operative time was significantly shorter in the LPEC group (22.3 ± 3.5 min) than in the OR group (27.8 ± 5.9 min) for bilateral hernia repair (p < 0.001). Postoperative recurrence was 1.3% (13/1035) in the OR group and 0.5% (6/1182) in the LPEC group (p = 0.056). Iatrogenic cryptorchidism occurred statistically more frequently in the OR group than in the LPEC group (0.4% vs. 0%, p = 0.013). In addition, the incidence of MCIH was 3.7% (33/887) in the OR group and 0.3% (3/1014) in the LPEC group (p < 0.01).ConclusionComparing to open technique, laparoscope-assisted single-needle LPEC provides a simple and effective option for pediatric inguinal hernia/hydrocele repair with excellent outcomes, a low incidence of recurrence, and reduced MCIH.

A case of bilateral inguinal hernia associated with Marfan syndrome

Marfan syndrome, a connective tissue disease, is associated with a high incidence and recurrence rate of inguinal hernia. We herein report a three-year-old boy with bilateral inguinal hernia associated with Marfan syndrome. While preoperative contrast-enhanced computed tomography (CT) revealed a left indirect inguinal hernia and a right direct inguinal hernia, laparoscopy showed bilateral patent processus vaginalis (PPV) and vulnerability of the abdominal wall at the bilateral medial inguinal fossae. In addition to laparoscopic percutaneous extraperitoneal closure (LPEC), open iliopubic tract repair was also performed. To our knowledge, this is the first report of a therapeutic strategy for pediatric inguinal hernia with Marfan syndrome. • Children with Marfan syndrome may develop direct inguinal hernias. • Computed tomography while awake in the prone position led to the diagnosis. • Combined laparoscopic and open hernia repair were useful.

Single-port laparoscopic percutaneous extraperitoneal internal ring closure for paediatric inguinal hernia using a needle grasper.

Single-site laparoscopic percutaneous extraperitoneal closure has been widely used for the repair of paediatric inguinal hernia. In this study, we aimed to introduce the usage of a needle grasper in single-port laparoscopic herniorrhaphy in children. In our study, 447 children with inguinal hernia underwent single-port laparoscopic percutaneous extraperitoneal closure between October 2018 and October 2021 in Shenzhen Children' hospital were retrospectively reviewed. Among 447 patients, there were 396 males and 51 females with a mean age of 2.24 ± 0.36years. A contralateral patent processus vaginalis was present in 165 unilateral hernia patients. All patients underwent laparoscopic percutaneous extraperitoneal closure successfully without converting to open operation. The mean operating time in unilateral and bilateral hernia patients were 10.23 ± 2.25 mine and 14.54 ± 2.81 mine respectively. One patient had subcutaneous emphysema, two male patients had inguinal hernia recurrence and none had complications such as hydrocele and testicular atrophy. Additional 0.3cm port was done in 4 cases. The mean follow-up time was 22.36 ± 4.56months. Single-port laparoscopic percutaneous extraperitoneal closure of paediatric inguinal hernia using a needle grasper is a feasible and safe procedure. It has the advantages of fewer skin surgical incisions, short operating time, low complication and low recurrence rate.

Laparoscopic Percutaneous Extraperitoneal Closure for Hydrocele of the Canal of Nuck in Children.

Background: Hydrocele of the canal of Nuck (HCN) is a rare cause of inguinal swelling in women. The optimal surgical procedure for HCN in children remains unclear. To assess the safety and efficacy of laparoscopic percutaneous extraperitoneal closure (LPEC) for HCN in a pediatric population, a retrospective study was conducted. In addition, to clarify the pathogenesis of HCN, we assessed the morphological findings of the internal inguinal ring (IIR). Materials and Methods: We retrospectively analyzed 10 consecutive female patients with HCN who underwent LPEC at our hospital between January 2010 and May 2020. Age, operative time, and complications were recorded. Concerning the findings of the IIR, we classified the morphological features as follows: Type 1 (flat), Type 2 (narrow patent processus vaginalis [PPV] with a peritoneal veil), and Type 3 (widely opening PPV). Results: The median age of patients who underwent LPEC was 3 (1-12) years. Although 2 patients showed contralateral inguinal hernia (IH), there were no cases of ipsilateral IH. All patients showed ipsilateral PPV, and the morphological features of the IIR were mostly classified as Type 3 (70%). In total, 6 of 8 HCN cases without preoperatively diagnosed contralateral IH had contralateral PPV (75%), and all were closed by LPEC. All operations were accomplished laparoscopically, and the postoperative course was uncomplicated, with no recurrences observed during the study period. Conclusions: LPEC is a safe and simple surgical approach to repair the HCN in children with minimal complications.

Assessment of laparoscopic inguinal hernia repair using the classification for single port laparoscopy in adolescents and young adults.

Inguinal hernia repair is one of the most common operations performed worldwide. No consensus currently exists regarding the most appropriate operation for inguinal hernia in adolescent and young adult (AYA) patients. This study aimed to evaluate the outcomes in AYA patients undergoing high ligation or mesh repair under laparoscopy by examining the location and size of the hernia orifice defect. We retrospectively reviewed all patients aged 15 to 40 years old who underwent laparoscopic hernia repair. Under single port laparoscopy, we classified the anatomic location (lateral, medial, or femoral) and size of the hernia orifice according to the classification by the European Hernia Society (EHS). A laparoscopic percutaneous extraperitoneal closure (LPEC) was performed on the patients with a lateral hernia with a hernia orifice defect size of ≤1.5 cm (L1). Transabdominal preperitoneal (TAPP) repair was performed on the patients with a lateral hernia with a hernia orifice defect size of >1.5 cm (L2 or 3). Overall, 40 patients underwent the mentioned surgical procedures. We performed LPEC on 22 patients, and TAPP on 18 patients. There were no intraoperative or postoperative complications and recurrences. This is the first report that evaluated the outcomes of AYA patients who underwent high ligation or mesh repair under laparoscopy by examining the location and size of the hernia orifice defect. Our data indicated that LPEC were effective and safe for AYA patients with small hernia orifice defect.

Laparoscopic extraperitoneal technique versus open inguinal herniotomy in children: historical controlled intervention study

ObjectiveTo compare surgical outcomes of percutaneous extraperitoneal simple purse string method of laparoscopic hernia (LH) repair with a traditional open inguinal hernia (OH) repair in children with indirect inguinal hernia...

Risk factors for metachronous contralateral inguinal hernia after laparoscopic percutaneous extraperitoneal closure for unilateral inguinal hernia in children.

We use the laparoscopic percutaneous extraperitoneal closure (LPEC) method as the standard procedure for pediatric inguinal hernia. Despite judging there to be no contralateral patent processus vaginalis (PPV) at the time of the first LPEC, we experienced five cases in which metachronous contralateral inguinal hernia (MCH) developed, so we report the characteristics, including the predictors. For pediatric inguinal hernia, the LPEC method was used in 1277 cases from 2005 to 2019 in our department. Of these, 374 patients underwent unilateral LPEC, and we compared the 5 patients with MCH onset and the 369 without MCH onset. The items to be examined were the gender, age, presence of a low birth weight, initial-onset side, and contralateral internal inguinal ring classification. There was no significant difference in the gender, age, initial-onset side, or contralateral internal inguinal ring classification between the two groups. Low-birth-weight infants were significantly more common among those with MCH than among those without MCH. The only predictor of a contralateral onset after LPEC for pediatric inguinal hernia was a low birth weight. Therefore, for the above-mentioned unilateral LPEC cases, the possibility of a contralateral onset after LPEC due to acquired factors rather than congenital factors should be considered.