Outcomes after muscle flap vs prosthetic patch repair for large congenital diaphragmatic hernias

Background

Repair of large congenital diaphragmatic hernia (CDH) defects still pose a significant challenge, as the defects cannot be repaired primarily. Two techniques have been widely used: autologous anterior abdominal wall muscle flap and prosthetic patch. The latter has been used more often. Our goal was to compare the short-term and long-term outcomes of these 2 approaches.

Methods

This is a retrospective review of all neonates undergoing CDH repair at our institution from 1969 to 2006.

Results

Of 188 children undergoing surgery for CDH, primary repair could not be accomplished in 51 infants (27%). Nineteen had muscle flap repair, and 32 had prosthetic patch repair (Gore-Tex [W.L. Gore and Associates, Flagstaff, AZ], n = 15; Marlex [Bard Inc, Cranston, NJ], n = 9; Surgisis [Cook, Bloomington, IN], n = 5; SILASTIC [Dow Corning, Midland, MI], n = 3). There was no significant difference in gestational age or birth weight between groups. Three patients developed an abdominal wall defect at the muscle flap donor site, but none required surgical intervention. Chest wall deformities were found in 9 patients, 3 after a muscle flap and 6 after a prosthetic patch (P = .7). Postoperative bowel obstruction occurred in 3 muscle flap patients and 1 patch patient (P = .2). There were 10 recurrences among survivors: 2 after a muscle flap and 8 after a prosthetic patch (P = .3) There were 2 deaths among the muscle flap patients (10%), and 3 deaths among the prosthetic patch repair patients (9%) (P = .1). Results were confirmed after controlling for age and comorbidities between both groups in a multivariate logistic regression.

Conclusion

These results suggest that autologous anterior abdominal wall muscle flap and prosthetic patch repairs provide similar short-term and long-term outcomes.     

Salvaging the severe congenital diaphragmatic hernia patient: is a silo the solution?

Background

Infants with severe congenital diaphragmatic hernia (CDH) requiring extracorporeal membrane oxygenation (ECMO) have a high morbidity and mortality. We hypothesized that placement of an abdominal wall silo and staged abdominal wall closure may reduce problems associated with decreased abdominal domain in CDH.

Methods

We performed a retrospective review and identified 7 CDH patients requiring ECMO who had a silastic abdominal wall silo between 2003 and 2006. Variables analyzed included survival, ECMO duration, duration of silo, time to discharge, and long-term outcome.

Results

Predicted mean survival for the entire cohort using the published CDH Study Group equation was 47% (range, 9%-86%). All 7 patients (100%) survived. Extracorporeal membrane oxygenation duration averaged 15 days (range, 5-19 days). Four of the patients (58%) were repaired with a silo on ECMO, and 3 (42%) had their repair after ECMO. The abdominal wall defect was closed at a mean of 21 days (range, 4-41 days). Hospital stay after silo placement averaged 54 days (range, 20-170 days) with no infections or wound complications.

Conclusions

Abdominal wall silo placement in infants with CDH requiring ECMO appears to be an effective strategy for decreased abdominal domain. Further studies are warranted to determine the efficacy of such a strategy for these high-risk CDH patients.     

Low recurrence rate after Gore-Tex/Marlex composite patch repair for posterolateral congenital diaphragmatic hernia

Purpose

Many different prosthetic materials have been used for repair of large posterolateral congenital diaphragmatic hernias (CDH), with high recurrence rates for hernias that cannot be primarily repaired. Since 1993, we have used a composite patch of Gore-Tex/Marlex to repair large CDHs and hypothesized that this repair leads to fewer recurrences.

Methods

This is a retrospective review of 137 consecutive patients with CDH cared for at a single institution from 1993 to 2004. Data collected include timing and method of repair and use of extracorporeal membrane oxygenation. Outcomes include hernia recurrence, complications, and death.

Results

One hundred thirty-seven patients with CDH were analyzed. Repair was not attempted in 12 because of disease severity. Primary repair was accomplished in 79 and 46 required patch repair. Of the 46 patients with patch repairs, 32 required extracorporeal membrane oxygenation, and 18 died before discharge. Of the 28 patch repair survivors, 1 (3.57%) developed a recurrence over a median follow-up of 47 months (range, 2-115 months). Overall survival was 77%.

Conclusions

Gore-Tex/Marlex composite patch repair of large CDHs in this complex patient population results in a lower recurrence rate than has been reported for other types of prosthetic diaphragm repair.     

Right-sided congenital diaphragmatic hernia: high utilization of extracorporeal membrane oxygenation and high survival

Purpose

The purpose of the study was to assess the treatment strategies and outcome of right-sided congenital diaphragmatic hernia (R-CDH), particularly extracorporeal membrane oxygenation (ECMO).

Methods

We reviewed the cases of 42 patients treated for R-CDH at our institution from 1991 to 2006. We gathered demographic information, documented ECMO use and the type of surgical repair, and compared outcomes with predicted survival as calculated by the CDH Study Group's equation.

Results

Of the 35 patients included in our statistical analysis (7 were excluded), 12 (34%) were born at our institution, all of whom were prenatally diagnosed with R-CDH. Nineteen patients (54%) required ECMO therapy. Extracorporeal membrane oxygenation was initiated after repair of the R-CDH in 2 patients (11%). Of those patients who went on ECMO before repair, 4 patients (21%) were repaired on ECMO, 9 patients (47%) underwent repair after ECMO, and 4 patients (21%) underwent ECMO but died before their R-CDH could be repaired. Primary repair of the diaphragm was possible in 15 cases (56%), and primary closure of the abdominal incision was possible in 15 of the 23 open repairs (65%). The mean predicted survival for all 35 patients was 63%, whereas 28 (80%) actually survived. Logistic regression showed a significant association between the presence of cardiac defects and mortality (odds ratio = 0.008, P = .014).

Conclusions

Our data suggest that patients with R-CDH have high ECMO utilization and may experience greater relative benefit from ECMO as evidenced by their higher-than-expected overall survival. Extracorporeal membrane oxygenation may be found to have a distinctive role in managing R-CDH. More high-powered series are needed to elucidate differences between R-CDH and left-sided CDH that may dictate alternate forms of management.     

Early repair of congenital diaphragmatic hernia on extracorporeal membrane oxygenation

Background

Timing of repair of congenital diaphragmatic hernia (CDH) in babies that require stabilization on extracorporeal membrane oxygenation (ECMO) remains controversial. Although many centers delay operation until physiologic stabilization has occurred or ECMO is no longer needed, we repair soon after ECMO has been initiated. The purpose of this study is to determine if our approach has achieved acceptable morbidity and mortality.

Methods

Charts of live-born babies with CDH treated at our institution between 1993 and 2007 were retrospectively reviewed. Data were then compared with The Congenital Diaphragmatic Hernia Study Group and Extracorporeal Life Support Organization registries.

Results

Forty-eight (39%) patients required ECMO Thirty-four of these 48 neonates were cannulated before operative repair. Venoarterial ECMO was used exclusively. The mean (SD) time of repair from cannulation was 55 (21) hours. Survival for this subset of patients was 71%. Three patients (8.8%) who underwent repair on ECMO experienced surgical site hemorrhage that required intervention.

Conclusion

Early repair of CDH in neonates on ECMO can be accomplished with acceptable rates of morbidity and mortality.     

Prosthetic patches for congenital diaphragmatic hernia repair: Surgisis vs Gore-Tex

Purpose

The sequelae of congenital diaphragmatic hernia (CDH) continue well beyond the perinatal period. Up to 50% of these patients have subsequent recurrent herniation or small bowel obstruction (SBO). A recent trend has been toward the use of bioactive prosthetic materials. We reviewed different patch closure techniques used for CDH repair at our institution and their association with these sequelae.

Methods

A retrospective review was performed of 152 records for patients with CDH. Newborns that underwent patch repair for CDH and survived for at least 30 days were included in the analysis. Primary outcomes evaluated were recurrent herniation and SBO. Two types of prostheses were examined, Gore-Tex, an artificial material, and Surgisis, a bioactive material.

Results

Twelve (44%) of 27 patients who had Surgisis repair had recurrent herniation. Seventeen (38%) of 45 patients who had a Gore-Tex repair had recurrent herniation. Two additional patients in each group presented with SBO. No significant difference in recurrent herniation rates was observed (P > .5). The time to recurrence was similar in both groups (log-rank, P = .75), with most recurrences (92% Surgisis, 76% Gore-Tex) occurring in the first year.

Conclusion

The rates of recurrent herniation and SBO after neonatal prosthetic patch repair of CDH were similar regardless of the prosthetic material used (Surgisis or Gore-Tex).     

A 22-year experience in global transport extracorporeal membrane oxygenation

Background/Purpose

Transport extracorporeal membrane oxygenation (ECMO) is currently available at 12 centers. We report a 22-year experience from the only facility providing global transport ECMO. Indications for transport ECMO include lack of ECMO services, inability to transport conventionally, inability to wean from cardiopulmonary bypass, extracorporeal cardiopulmonary resuscitation, and need to move a patient on ECMO for specialized services such as organ transplantation.

Methods

Retrospective database review of children undergoing inhouse and transport ECMO from 1985 to 2007.

Results

Sixty-eight children underwent transport ECMO. Fifty-six were transported on ECMO into our facility. The remaining 12 were moved between 2 outside locations. Ground vehicles and fixed-wing aircraft were used. Distance transported was 8 to 7500 miles (13-12 070 km), mean 1380 miles (2220 km). There were 116 inhouse ECMO runs. No child died during transport. Survival to discharge after transport ECMO was 65% (44/68) and, for inhouse ECMO, was 70% (81/116).

Conclusions

Transport ECMO is feasible and effective, with survival rates comparable to inhouse ECMO. We have used transport ECMO to help children at non-ECMO centers with pulmonary failure who have not improved with inhaled nitric oxide and high-frequency ventilation. We have also transported a child after extracorporeal cardiopulmonary resuscitation, which may represent an emerging indication for transport ECMO. Transport ECMO often is the only option for children too unstable for conventional transport or those already on ECMO and requiring a specialized service at another facility, such as organ transplantation.     

Laparoscopy-assisted surgery for prenatally diagnosed small bowel atresia: simple, safe, and virtually scar free

Purpose

The aim of this study was to describe a new technique for the surgical management of prenatally diagnosed small bowel atresia.

Methods

Under general anesthesia, a 5-mm trocar was inserted using an open technique through an intraumbilical incision. The proximal atretic bowel end was identified using laparoscopy and mobilized toward the umbilicus using an additional 3-mm trocar inserted in the left lower quadrant. The umbilical trocar then was removed, and a ring retractor was inserted into the trocar site and used to expand the wound to deliver both atretic bowel ends. The bowel was repaired and returned to the abdomen through the umbilical wound. The umbilical fascia and skin were closed conventionally.

Results

Three patients were reviewed. Two had minimal abdominal distension, and the atretic bowel ends could be identified easily; laparoscopy-assisted surgery was successful. The third case had significant dilatation, and laparotomy was required. Postoperatively, there was minimal abdominal scarring, and the umbilicus was normal in appearance.

Conclusions

Although this experience is limited to 3 patients, this technique is simple, safe, and virtually scar free and can be applied for the treatment of neonates with prenatally diagnosed small bowel atresia, especially if there is minimal abdominal distension at birth.     

The hidden mortality of congenital diaphragmatic hernia: a 20-year review

Aims

The true mortality associated with congenital diaphragmatic hernia (CDH) is hidden because survival analyses do not include fetuses with CDH. A retrospective review of all postmortems (PMs) with a diagnosis of CDH over a 20-year period was carried out to highlight this hidden mortality and also measure the nature and number of associated anomalies.

Methods

Postmortem case record details were reviewed for the period January 1986 to December 2005. Data were collected on live birth, stillbirth, therapeutic abortion, and spontaneous abortion.

Results

There was a decline in the annual number of PMs during the period of the study. The median for the four 5-year intervals being 609 (570-657), 528 (488-565), 515 (413-537), and 373 (357-388). A total of 130 PMs were identified, which included a diagnosis of CDH; 97 (75%) were left sided, 22 (17%) were right sided, and 11 (8%) were bilateral. There were 69 live births, 46 therapeutic abortions, 10 stillbirths, and 5 intrauterine deaths; 22% were right sided/bilateral in the live and therapeutic abortion groups, whereas 53% were right sided/bilateral in the latter 2 groups. Of 130, 82 (63%) had major associated anomalies, and 50% of these had at least 1 further major anomaly. The commonest categories of anomalies were cardiac (30), gastrointestinal/abdominal wall defect (28), and neural tube defects (25).

Conclusions

The true incidence of CDH is considerably higher than that seen in neonatal surgical practice. The decline in number of PMs in our region will exacerbate the underestimation of the true incidence. There is a higher incidence of right-sided/bilateral hernias and more than one major anomaly in those who die in utero.     

Effectiveness of diaphragmatic repair using an abdominal muscle flap in patients with recurrent congenital diaphragmatic hernia

Background/Purpose

Recurrent congenital diaphragmatic hernia (Re-CDH) is a well-known complication of CDH repair. Although surgical treatment is required for Re-CDH, the question regarding which technique is the optimal treatment has not yet been elucidated. We performed a repair using an abdominal muscle flap (AMF) for Re-CDH and herein report our experience.

Patients and Results

Four patients using AMF had left Re-CDH. The patient's age at operation was around 1 year old in all patients. In the first repair during the neonatal period, a Gore-Tex patch was required for the large defect in 3 patients, whereas a primary closure was selected in 1 patient because the anterior diaphragm remained as a partial remnant. In the 3 patients in whom a Gore-Tex patch was used in the first operation, recurrence occurred twice. All of the patients suffered from both pulmonary hypertension and growth retardation. A repair using AMF (the flap of both the internal oblique and the transversalis abdominal muscle) was performed in all patients. The clinical course was good in all patients, with an improvement of both pulmonary hypertension and growth retardation without any recurrence of CDH.

Conclusion

The use of an AMF was thus found to be an effective technique for repairing a large defect in Re-CDH.     

Use of a non-cross-linked porcine dermal scaffold in abdominal wall reconstruction

Background

Reconstruction of complex abdominal wall defects is challenging. The use of prosthetic mesh can be associated with surgical site infection, fistula formation, and adhesions. This study presents our experience using a non-cross-linked porcine dermal scaffold (NCPDS) in abdominal wall reconstruction.

Methods

Patients undergoing abdominal wall reconstruction with NCPDS between May 2006 and January 2008 underwent a retrospective chart review. Demographics, indications for NCPDS placement, surgical technique, complications, and follow-up data were evaluated.

Results

Sixteen patients were identified in whom NCPDS was implanted into complex abdominal wall defects. These included 13 planned and 3 emergency surgeries. Indications for surgery included delayed reconstruction of giant ventral hernia secondary to decompressive laparotomy and open management of abdominal trauma, recurrence of large incisional hernia, temporary coverage of open abdomen secondary to intra-abdominal catastrophes, and open abdominal closure owing to compartment syndrome secondary to necrotizing fasciitis. In all, NCPDS was positioned in a subfascial underlay technique. Forty-four percent required a combination of components separation and NCPDS insertion. At a mean follow-up period of 16.5 months, the majority had desirable outcomes. Complications included seroma (21%), superficial wound dehiscence (7%), recurrence (7%), and infection (7%). Two patients died from multiorgan failure unrelated to NCPDS placement. The material only had to be removed in 1 patient because of wound infection and superficial wound dehiscence.

Conclusions

NCPDS seems to be a safe and effective alternative to prosthetic mesh in the reconstruction of complicated abdominal wall defects.     

Laparoscopic patch repair of diaphragmatic hernias with Surgisis

Background

Laparoscopic repair of congenital diaphragmatic hernias has been sparsely reported. Moreover, each report has primarily been a single operative case. In most of the reports, prosthetic mesh has not been used, and when used, it has been nonabsorbable in nature. Most of these case reports have documented only a few months of clinical follow-up.

Methods

After institutional review board approval (No. 01-12-115X), the clinical course and outcome of 3 patients undergoing laparoscopic repair of foramen of Morgagni and Bochdalek hernias using 4-ply Surgisis soft tissue graft (Cook Inc, Bloomington, Ind) were reviewed to determine if this approach is appropriate.

Results

In 2001, 2 patients, ages 9 months and 14 years, underwent laparoscopic foramen of Morgagni repair and one 5-day-old underwent laparoscopic foramen of Bochdalek repair using Surgisis soft tissue graft as a patch to close the diaphragmatic defects because there was too much tension with primary repair. In each case, the prosthesis was secured to the rim of the defect using interrupted silk sutures tied intracorporally. The mean operative time for repair of the Morgagni defects was 230 minutes with a postoperative discharge of 1 and 2 days. For the foramen of Bochdalek repair, the operative time was 204 minutes, and the patient was discharged at 3 weeks. No complications have occurred during or after any of the procedures, but the oldest patient underwent diagnostic laparoscopy 3 months postoperatively for a radiographic finding of suspected recurrence. At laparoscopy, the patch was intact, and no diaphragmatic hernia was noted.

Conclusions

Laparoscopic repair of congenital diaphragmatic defects using prosthetic material is possible although the operative time required is around 3.5 hours. Because of the brief postoperative course, the laparoscopic approach appears justified in the nonneonatal patients. Whether this approach is appropriate for repair of neonatal Bochdalek hernias remains unclear.     

Chronic abdominal wall pain—A diagnostic challenge for the surgeon

Background

Chronic abdominal wall pain (CAWP) occurs in about 30% of all patients presenting with chronic abdominal pain.

Methods

The authors review the literature identified in a PubMed search regarding the abdominal wall as the origin of chronic abdominal pain.

Results

CAWP is frequently misinterpreted as visceral or functional abdominal pain. Misdiagnosis often leads to a variety of investigational procedures and even abdominal operations with negative results. With a simple clinical test (Carnett's test), >90% of patients with CAWP can be recognized, without risk for missing intra-abdominal pathology.

Conclusion

The condition can be confirmed when the injection of local anesthetics in the trigger point(s) relieves the pain. A fasciotomy in the anterior abdominal rectus muscle sheath through the nerve foramina of the affected branch of one of the anterior intercostal nerves heals the pain.     

Effect of preextracorporeal membrane oxygenation ventilation days and age on extracorporeal membrane oxygenation survival in critically ill children

Purpose

The aim of the study is to test the effect of age and preextracorporeal membrane oxygenation (pre-ECMO) days of ventilation on ECMO survival in the pediatric population.

Methods

Retrospective analysis of noncardiac, pediatric (age >30 days) ECMO patients for the period January 1984 to June 2006. Pre-ECMO demographic, ventilatory, and lung injury severity variables were modeled with stepwise logistic regression to estimate survival probabilities associated with pre-ECMO ventilation duration and patient age. Patients were excluded from review for the following: pre-ECMO cardiac arrest, pre-ECMO ventilation of more than 30 days (chronic), or multiple runs on ECMO.

Results

For the period of review, 2550 patients met inclusion/exclusion criteria. The population had a mean age of 3.6 ± 5.1 years (median age, 1 year). The mean pre-ECMO days of ventilation were 5.2 ± 4.9 (median, 4 days). The overall survival probability was 58.6%. The mean oxygen index and Pao₂/Fio₂ ratio were 62.2 ± 48.2 and 95.5 ± 48.2, respectively. The population overall demonstrated a statistically significant, exponential decline in survival as pre-ECMO days of ventilation increased (P < .05). For each additional year of age, survival decreased by an average of 2.5%. For each additional day of pre-ECMO ventilation, survival decreased by an average of 2.9%. Younger ages were generally associated with higher survival probabilities at each ventilation day.

Conclusions

In the pediatric population, survival decreases significantly as pre-ECMO ventilator days increase. Survival is also inversely related to patient age. Thus, patient age and duration of ventilation should be considered when evaluating suitability for ECMO.     

Diaphragmatic repair through fetal tissue engineering: a comparison between mesenchymal amniocyte- and myoblast-based constructs

Purpose

We have previously shown that fetal tissue engineering is a preferred alternative to diaphragmatic repair in a large animal model. This study was aimed at comparing diaphragmatic constructs seeded with mesenchymal amniocytes and fetal myoblasts in this model.

Methods

Neonatal lambs (n = 14) underwent repair of an experimental diaphragmatic defect with identical scaffolds, either seeded with labeled autologous cells (mesenchymal amniocytes in group 1 and fetal myoblasts in group 2) or as an acellular graft (group 3). At 1 to 12 months postoperatively, implants were harvested for multiple analyses.

Results

Repair failure (reherniation or eventration) was significantly higher in group 3 than in groups 1 and 2, with no difference between groups 1 and 2. Seeded fetal myoblasts quickly lost their myogenic phenotype in vivo. All grafts contained cells with a fibroblastic-myofibroblastic profile. Elastin concentrations and both modular and ultimate tensile strengths were significantly higher in group 1 than in groups 2 and 3. There were no differences in glycosaminoglycans and type I collagen levels among the groups.

Conclusions

Diaphragmatic repair with a mesenchymal amniocyte-based engineered tendon leads to improved structural outcomes when compared with equivalent fetal myoblast-based and acellular grafts. The amniotic fluid is a preferred cell source for tissue-engineered diaphragmatic reconstruction.     

Novel titanium constructs for chest wall reconstruction in children

Purpose

We have previously reported the use of the vertical expandable prosthetic titanium rib (VEPTR) for treatment of thoracic dystrophy. This report describes our experience with this device and other novel titanium constructs for chest wall reconstruction.

Methods

This is a retrospective chart review of all children and adolescents undergoing chest wall reconstruction with titanium constructs between December 2005 and May 2010.

Results

Six patients have undergone chest wall reconstruction with VEPTR or other titanium constructs. Four had chest wall resection for primary malignancy, 1 had metastatic chest wall tumor resection, and 1 had congenital chest wall deformity. There were no immediate complications, and all patients have exhibited excellent respiratory function with no scoliosis.

Conclusions

Chest wall reconstruction after tumor resection or for primary chest wall deformities can be effectively accomplished with VEPTR and other customized titanium constructs. Goals should be durable protection of intrathoracic organs and preservation of thoracic volume and function throughout growth. Careful preoperative evaluation and patient-specific planning are important aspects of successful reconstruction.     

Fetal lung-head ratio is not related to outcome for antenatal diagnosed congenital diaphragmatic hernia

We asked if fetal lung-to-head ratio (LHR) of 1.0 or lower or liver herniation had a statistical effect on survival or need for extracorporeal membrane oxygenation (ECMO), compared with LHR above 1.0 in patients with congenital diaphragmatic hernia (CDH).

Methods

Antenatal records of all patients diagnosed with CDH from January of 2002 to June of 2005 were examined. Inclusion criteria were isolated left-sided CDH and absence of significant cardiac or other anomalies/syndromes, treated solely at this institution. Lung-to-head ratio values were compared based on the value currently proposed for fetal intervention: LHR of 1.0 or lower vs LHR above 1.0. Outcome was assessed as survival (discharge to home) or need for ECMO.

Results

Twenty-eight patients met inclusion criteria. Overall survival was 86% (24/28). Postnatal survival in fetuses with LHR of 1.0 or lower (8/11) was not statistically different from LHR above 1.0 (16/17) (73% vs 94%, P = .114). The need for ECMO in the group with LHR of 1.0 or lower (3/11) was not significantly different from those with LHR above 1.0 (1/17) (27% vs 6%, P = .114). Herniation of the fetal liver into the chest did not affect survival or need for ECMO (P = .228).

Conclusion

Neither LHR of 1.0 or lower nor liver herniation identified a risk factor significant enough to warrant fetal intervention. Multicenter studies may be more appropriate to investigate this clinical problem.     

Martius repair in urethrovaginal defects

Aim

To repair a urethrovaginal defect in childhood is a challenge for a pediatric surgeon. Martius fat-pad flap repair is being used in women successfully. Here, we report 2 girls who had Martius repair for their urethrovaginal defects.

Method

Topical estriol and asiaticoside perineally were administered for preoperative 3 weeks to reinforce the tissues. Martius repair was done using 1-sided labial fat-pad flap. Urethral and bladder catheters were inserted. Urethral catheter was removed on postoperative day 14 and bladder catheter on day 21 after controlling residual urine.

Patients

Patient 1, a 6-year-old girl, had lipomeningocele repair at the age of 18 months and had an iatrogenic urethrovaginal fistula that is caused by catheter insertion. She developed urinary incontinence, and 3 primary repair attempts were unsuccessful.Patient 2 is a 5-year-old girl who had pouch colon with persistent cloacal malformation and had posterior anorectovaginourethroplasty. The urethrovaginal septum did not heal, and she was incontinent. One attempt of primary repair was unsuccessful. The urethrovaginal wall was completely open at the time of Martius repair in both patients.

Results

Urethral wall was completely healed after Martius repair in both patients.

Conclusion

Martius fat-pad flap repair can be used to repair urethrovaginal fistulas in girls. It has both functionally and cosmetically good results, and neourethra is easily catheterizable.