It is all about form and function: a new approach to giant neonatal sacrococcygeal teratomas.

INTRODUCTION: Giant sacrococcygeal teratomas (GSCTs) involve severe deformation of the buttock region in addition to potential functional impacts. Little interest has been given to improving the aesthetic post-operative appearance in children with these tumours. METHODS: We describe a new technique for immediate reconstruction of GSCTs using buried dermal-fat flaps and a low transverse scar in the infragluteal fold. RESULTS: Our technique allows wide exposure for tumour resection and functional restoration of the pelvic floor while placing the scars in anatomical locations and restoring buttock aesthetics including gluteal projection and infragluteal fold definition. CONCLUSION: Reestablishment of function and form should be kept in mind at initial surgery in GSCT surgery to maximize results and enhance post-operative outcomes. LEVEL OF EVIDENCE: IV.

A new ovine model of spine and chest wall deformity at birth with alteration of respiratory system mechanics and lung development: a feasibility study.

PURPOSE: To develop an animal model of spine and chest wall deformity (CWD) at birth and to evaluate its effects on respiratory system mechanics and lung development. METHODS: A spine and CWD was created in utero between 70 and 75 days of gestation in six ovine fetuses by resection of the seventh and eighth left ribs. Two days after birth, respiratory system mechanics was assessed in anesthetized lambs using the flexiVent apparatus, followed by postmortem measurement of lung mechanics as well as histological lung analysis. RESULTS: A range of severity of CWD was found (Cobb angle from 0° to 48°) with a mean decrease in compliance of 47% and in inspiratory capacity of 39% compared to control lambs. Proof-of-concept histological analysis in one lamb showed marked lung hypoplasia. CONCLUSION: Our ovine model represents a pilot proof-of-concept study evaluating the impact of a spine and CWD present at birth on lung respiratory mechanics and development. This study lays down the groundwork for future studies evaluating the impact of these deformities on lung development and potential treatments. These slides can be retrieved under Electronic Supplementary Material.

[All large necrotic and hemorrhagic kidney tumors in children are not necessarily malignant: A case of a 7-month-old child]. / Les volumineuses tumeurs rénales nécrotiques et hémorragiques ne sont pas toutes malignes même en pédiatrie : à propos d'un cas chez un enfant de 7 mois.

We report the case of a large tumor in the left kidney with necrotic and hemorrhagic features in a 7-month-old child, which was clinically and radiologically suggestive of a nephroblastoma. The tumor was a nodular mass measuring 8cm in diameter occupying two thirds of the kidney and presenting areas of necrosis and hemorrhage. No capsular rupture or renal sinus infiltration were found. Adjacent renal parenchyma appeared mascroscopically normal. Histologically, the tumor showed a strictly tubulopapillary architectural pattern with numerous psammomas. The initial hypothesis was a purely epithelial nephroblastoma. However, this hypothesis was rejected due to some immunohistochemical and histological characteristics and the final diagnosis was a metanephric adenoma. Metanephric adenoma is an exceptionally rare benign renal tumor in children. However, pathologists need to keep it in mind because simple surgical excision is curative.

Predicting Perinatal Outcome from Prenatal Ultrasound Characteristics in Pregnancies Complicated by Gastroschisis.

INTRODUCTION: The objective of the study was to establish the predictive value of prenatal ultrasound markers for complex gastroschisis (GS) in the first 10 days of life. MATERIAL AND METHODS: In this retrospective cohort study over 11 years (2000-2011) of 117 GS cases, the following prenatal ultrasound signs were analyzed at the last second- and third-trimester ultrasounds: intrauterine growth restriction, intra-abdominal bowel dilatation (IABD) adjusted for gestational age, extra-abdominal bowel dilatation (EABD) ≥25 mm, stomach dilatation, stomach herniation, perturbed mesenteric circulation, absence of bowel lumen and echogenic dilated bowel loops (EDBL). RESULTS: Among 114 live births, 16 newborns had complex GS (14.0%). Death was seen in 16 cases (13.7%): 3 intrauterine fetal deaths, 9 complex GS and 4 simple GS. Second-trimester markers had limited predictive value. Third-trimester IABD, EABD, EDBL, absence of intestinal lumen and perturbed mesenteric circulation were statistically associated with complex GS and death. IABD was able to predict complex GS with a sensitivity of 50%, a specificity of 91%, a positive predictive value of 47% and a negative predictive value of 92%. DISCUSSION: Third-trimester IABD adjusted for gestational age appears to be the prenatal ultrasound marker most strongly associated with adverse outcome in GS.

Ovine model of congenital chest wall and spine deformity: From birth to 3 months follow-up.

Background: The evolution and treatment of lung alterations related to congenital spine and chest wall deformities (CWD) are poorly understood. Most animal models of CWD created postnatally were not evaluated for respiratory function. The goal of our study was to evaluate the effects of a CWD induced in utero on lung growth and function in an ovine model. Methods: A CWD was induced in utero at 70-75 days of gestation in 14 ovine fetuses by resection of the 7th and 8th left ribs. Each non-operated twin fetus was taken as control. Respiratory mechanics was studied postnatally in the first week and at 1, 2, and 3 months. Post-mortem respiratory mechanics and lung histomorphometry were also assessed at 3 months. Results: Eight out of 14 CWD lambs (57%) and 14 control lambs survived the postnatal period. One severe and five mild deformities were induced. At birth, inspiratory capacity (25 vs. 32 mL/kg in controls), and dynamic (1.4 vs. 1.8 mL/cmH2O/kg), and static (2.0 vs. 2.5 mL/cmH2O/kg) respiratory system compliances were decreased in CWD lambs. Apart from a slight decrease in inspiratory capacity at 1 month of life, no other differences were observed in respiratory mechanics measured in vivo thereafter. Postmortem measurements found a significant decrease in lung compliance-for each lung and for both lungs taken together-in CWD lambs. No differences in lung histology were detected at 3 months in CWD animals compared to controls. Conclusions: Our study is the first to assess the effects of a prenatally induced CWD on lung development and function from birth to 3 months in an ovine model. Our results show no significant differences in lung histomorphometry at 3 months in CWD lambs compared to controls. Resolution at 1 month of the alterations in respiratory mechanics present at birth may be related to the challenge in inducing severe deformities.

Shining light on the noradrenergic system.

Despite decades of research on the noradrenergic system, our understanding of its impact on brain function and behavior remains incomplete. Traditional recording techniques are challenging to implement for investigating in vivo noradrenergic activity, due to the relatively small size and the position in the brain of the locus coeruleus (LC), the primary location for noradrenergic neurons. However, recent advances in optical and fluorescent methods have enabled researchers to study the LC more effectively. Use of genetically encoded calcium indicators to image the activity of noradrenergic neurons and biosensors that monitor noradrenaline release with fluorescence can be an indispensable tool for studying noradrenergic activity. In this review, we examine how these methods are being applied to record the noradrenergic system in the rodent brain during behavior.

Tu-be or not tu-be? Is routine endotracheal intubation necessary for successful bedside reduction and primary closure of gastroschisis?

BACKGROUND: Wide practice variation exists in the management of gastroschisis. Routine endotracheal intubation for bedside closure may lead to longer duration of mechanical ventilation. METHODS: The Canadian Association of Pediatric Surgery Network gastroschisis dataset was queried for all patients undergoing attempted bedside reduction and closure. Patients with evidence of intestinal necrosis or perforation were excluded. A propensity score analysis was used to compare the rate of successful primary repair and post-operative outcomes between intubated and non-intubated patients. RESULTS: In propensity score matched analysis, the successful primary repair rate did not reach statistical significance between patients who were intubated for attempted bedside closure and those who were not intubated (Odds Ratio: 2.18, 95% Confidence Interval: 0.79, 6.03). Intubated patients experienced 3.02 more ventilator days than patients who were not intubated at the time of initial attempted closure. Other post-operative parameters were similar between both groups. CONCLUSIONS: It is reasonable to attempt primary bedside gastroschisis closure without intubation in otherwise healthy infants.

Implementing a standardized gastroschisis protocol significantly increases the rate of primary sutureless closure without compromising closure success or early clinical outcomes.

PURPOSE: Standardized protocols have been shown to improve outcomes in several pediatric surgical conditions. We implemented a multi-disciplinary gastroschisis practice bundle at our institution in 2013. We sought to evaluate its impact on closure type and early clinical outcomes. METHODS: We performed a retrospective review of uncomplicated gastroschisis patients treated at our institution between 2008-2019. Patients were divided into two groups: pre- and post-protocol implementation. Multivariate logistic regression was used to compare closure location, method, and success. RESULTS: Neonates (pre-implementation n = 53, post-implementation n = 43) were similar across baseline variables. Successful immediate closure rates were comparable (75.5% vs. 72.1%, p = 0.71). The proportion of bedside closures increased significantly after protocol implementation (35.3% vs. 95.4%, p < 0.01), as did the proportion of sutureless closures (32.5% vs. 71.0%, p < 0.01). Median postoperative mechanical ventilation decreased significantly (4 days IQR [3, 5] vs. 2 days IQR [1, 3], p < 0.01). Postoperative complications and duration of parenteral nutrition were equivalent. After controlling for potential confounding, infants in the post-implementation group had a 44.0 times higher odds of undergoing bedside closure (95% CI: 9.0, 215.2, p < 0.01) and a 7.7 times higher odds of undergoing sutureless closure (95% CI: 2.3, 25.1, p < 0.01). CONCLUSIONS: Implementing a standardized gastroschisis protocol significantly increased the proportion of immediate bedside sutureless closures and decreased the duration of mechanical ventilation, without increasing postoperative complications. Level of Evidence III Type of Study Retrospective comparative study.

Comparative outcomes in intestinal atresia: a clinical outcome and pathophysiology analysis.

OBJECTIVE: To describe the outcomes of 130 intestinal atresias between 1982 and 2007. METHODS: Records were analyzed for location, demographics, prenatal diagnosis, birth weight, associated anomalies, surgery, establishment of oral intake, re-interventions and mortality. Statistical analyses were performed using Fisher test and ANOVA. RESULTS: There were 59 duodenal (30 male), 63 jejuno-ileal (34 male) and 8 colonic atresias (3 male). Prenatal diagnosis was established in 27 (46%) duodenal (DA), 26 (41%) jejuno-ileal (JIA) and 1 (12.5%) colonic atresias (CA). The mean birth weights, 2,380.5 g (SD 988) DA, 2,814 g (SD 755) JIA and 3,153 g (SD 527) CA were significantly different (p = 0.011). The mean gestational ages were 36, 37 and 37 weeks in DA, JIA and CA, respectively (p-NS). Associated congenital anomalies were seen in 41 (76%) DA, 32 (52%) JIA and 3 (38%) CA (p = 0.08, NS). The median time to full oral feeds after surgery was 18 days in DA, 20 days in JIA and 15.6 days in CA, respectively (p > 0.05). Eight patients with DA and nine patients with JIA underwent repeat surgery for adhesive obstruction. Adhesive bowel obstruction was most common in the first year after surgery in both groups (15/17). Gastroschisis was seen in six (10%) of JIA and three (35%) of CA. Two patients in the JIA group underwent bowel lengthening. Patients with gastroschisis and those with associated anomalies needed prolonged duration of TPN after JIA correction. There was no mortality in the duodenal atresia and colonic atresia groups. Six patients in the JIA group died, three of severe atresias coupled with multiple anomalies and three of cholestasis and sepsis. CONCLUSION: Distal atresias are difficult to diagnose antenatally. Proximal atresias have a significantly lower birth weight than distal atresias. Associated anomaly screening is important in all atresias.

Non-additive dietary effects in juvenile slider turtles, Trachemys scripta.

Non-additive dietary effects occur when nutritional gains from a mixed diet are greater than or less than that predicted by summing the gains from individual diet items. Both positive and negative effects occur in adult slider turtles, Trachemys scripta. Such effects may also be important to juvenile T. scripta as they ontogenetically switch from carnivorous to herbivorous diets. The purpose of this study was to determine if juveniles experience non-additive effects and to assess the underlying mechanism. Two feeding trials were conducted. In Trial 1, juveniles were fed 100% duckweed, Lemna valdiviana, 100% grass shrimp, Palaemontes paludosus, or a mixed diet containing 81% duckweed and 19% shrimp. In Trial 2, juveniles were fed 100% duckweed, Lemna minor, 100% cricket, Acheta domesticus, or one of three mixed diets containing duckweed and cricket in varying percentages (22%, 39% and 66% cricket). Similar to adults, a negative non-additive effect was demonstrated on the 19% shrimp and 22% cricket diets. However, the positive effect found in adults was not observed. Intake varied dramatically between the plant and animal diets, resulting in differences in transit time that could explain the non-additive effect. These results offer some insight into understanding ontogenetic diet shifts in turtles.

Catastrophic cardiac injuries encountered during the minimally invasive repair of pectus excavatum.

This paper presents four severe cardiac injuries that occurred in patients who underwent the minimally invasive repair of pectus excavatum (MIRPE). These complications occurred in different clinical settings, namely in a patient with an extremely severe form of pectus, in a patient who had previously undergone an open repair, after a previous open heart surgery, and at the time of bar removal. The purpose of this article is to review the circumstances leading to these cardiac injuries, share what we have learned from these patients, and hopefully help avoid these complications in the future.

Prognostic factors in jejuno-ileal atresia.

OBJECTIVE: Primarily to study morbidity and mortality in jejuno-ileal atresias (JIA) and prognostic factors for outcome. Secondarily to look at the incidence of reintervention. METHODS: Retrospective review of 63 patients diagnosed with JIA over a 30-year period (1975-2005). RESULTS: Sixty-three patients (34 male) of mean gestational age 36 weeks and mean birth weight 2,858 g with JIA were studied. There were 14 type I, 14 type II, 16 type IIIA, 9 type IIIB, and 10 type IV atresias. Thirty-three patients (52%) had associated anomalies. Fifty-one patients underwent resection and anastamosis, five patients Bishop-Koop procedure, five ileostomies, and one strictureplasty. Intestinal dilatation severe enough to warrant surgical intervention was seen in seven patients with the more severe variants of atresia. Five tapering procedures, one Bianchi operation and one STEP procedure were performed. Average hospital stay was 41 days (8-332 days). Fifty-six were alive at follow ups averaging 1.7 years (6 months to 11 years). Nine patients needed reoperations for adhesions before the first year of life. There were seven deaths. Most patients who died had associated anomalies (P = 0.017) or types IV/V atresias (P = 0.007). CONCLUSION: Mild atresias have an excellent prognosis and long-term survival. Severe atresias are associated with longer PN support and secondary procedures for intestinal failure. Associated anomalies adversely affect outcomes in JIA.

Prenatal prediction of survival in congenital diaphragmatic hernia: An audit of postnatal outcomes.

PURPOSE: Effective antenatal counseling in congenital diaphragmatic hernia (CDH) relies on proper measurement of prognostic indices. This quality initiative audited the accuracy of prenatal imaging with postnatal outcomes at two tertiary pediatric referral centers. METHODS: Prenatal lung-head ratio (LHR) and total fetal lung volume (TFLV) for CDH patients treated between 2006 and 2017 were retrieved. Study inclusion required at least one LHR or TFLV measurement between 24 and 32 weeks gestational age. Postnatal outcomes [mortality, extracorporeal life support (ECLS) need, patch repair, persistent pulmonary hypertension, oxygen requirement at 28 days] were abstracted from the Canadian Pediatric Surgery Network (CAPSNet) database and local chart review. Univariate and descriptive analyses were conducted. RESULTS: Eighty-two of 121 eligible CDH patients (68%) were included. Overall mortality, ECLS rates, and patch repair were 33%, 12.5%, and 45%, respectively. Lower LHR values correlated with increased rates of each outcome and persisted despite multiple measurements. Values obtained were higher than those in published schemata. LHR values >45% were most associated with survival, avoidance of ECLS, and primary repair. TFLV values only correlated with mortality and patch repair. CONCLUSIONS: This audit confirms that LHR and TFLV values predict CDH outcomes. However, absolute values obtained require careful interpretation and internal review. LEVEL OF EVIDENCE: IV.

Nonadditive interactions between animal and plant diet items in an omnivorous freshwater turtle Trachemys scripta.

Nonadditive interactions occur when diet items interact with one another such that the net energy or nutrient gain from a mixed diet differs from that predicted by summing the gains from individual diet components. We quantified nonadditive effects between duckweed, Lemma valdiviana, and grass shrimp, Palaemontes paludosus, in the freshwater turtle Trachemys scripta. We fed turtles 100% duckweed, 100% shrimp, and two mixed diets containing 67% duckweed, 33% shrimp and 14% duckweed, 86% shrimp (dry matter basis). During each feeding trial, we measured intake, digestibility, and transit time of the diet, and upon conclusion, short-chain fatty acid concentrations in turtle digestive tracts. Digestibility was lower on the 67% duckweed diet, but higher on the 14% diet. These apparent nonadditive interactions may be due to differences in transit time of duckweed and shrimp. We believe this is the first evidence of two diet items producing opposing nonadditive effects when fed in different ratios.

Ontogenetic diet shifts and digestive constraints in the omnivorous freshwater turtle Trachemys scripta.

Many reptiles undergo an ontogenetic diet shift from carnivory to herbivory. In this study, we used the yellow-bellied slider turtle, Trachemys scripta, as a model to evaluate whether juvenile turtles are carnivorous because physiological constraints preclude herbivory. We conducted feeding trials in which we fed juvenile and adult turtles a duckweed plant, Lemna valdiviana, or a freshwater grass shrimp, Palaemontes paludosus, for 5 wk. During the trials, we measured mass-specific intake, digestibility, and digestible intake for both size classes, as well as juvenile growth. At the end of the trials, we measured the nutrient composition of the juvenile turtles. Juveniles fed shrimp grew 3.2 times faster than those fed duckweed and had equivalent lipid stores. Digestive processing in juveniles was extremely efficient on the shrimp diet, with higher mass-specific intakes than adults and very high digestibilities (97%). Juveniles digested duckweed as well as adults did; however, their intake of this diet was limited, possibly by the time required for fermentation. We concluded that although juveniles can process plant material, an animal diet allows for greater juvenile growth, which in turtles is linked to higher survivorship and increased future reproductive success.

Predictive factors at birth of the severity of gastroschisis.

AIM: To establish children born with gastroschisis (GS). METHODS: We performed a retrospective study covering the period from January 2000 to December 2007. The following variables were analyzed for each child: Weight, sex, apgar, perforations, atresia, volvulus, bowel lenght, subjective description of perivisceritis, duration of parenteral nutrition, first nasogastric milk feeding, total milk feeding, necrotizing enterocolitis, average period of hospitalization and mortality. For statistical analysis, descriptive data are reported as mean ± standard deviation and median (range). The non parametric test of Mann-Whitney was used. The threshold for statistical significance was P < 0.05 (Two-Tailed). RESULTS: Sixty-eight cases of GS were studied. We found nine cases of perforations, eight of volvulus, 12 of atresia and 49 children with subjective description of perivisceritis (72%). The mortality rate was 12% (eight deaths). Average duration of total parenteral nutrition was 56.7 d (8-950; median: 22), with five cases of necrotizing enterocolitis. Average length of hospitalization for 60 of our patients was 54.7 d (2-370; median: 25.5). The presence of intestinal atresia was the only factor correlated with prolonged parenteral nutrition, delayed total oral milk feeding and longer hospitalization. CONCLUSION: In our study, intestinal atresia was our predictive factor of the severity of GS.

Alternative competition-induced digestive strategies yield equal growth, but constrain compensatory growth in red-eyed treefrog larvae.

Compensatory growth is well documented across taxa and provides a fitness advantage to animals who would otherwise reach a smaller reproductive size. We investigated the role of competition-induced gut plasticity in facilitating a compensatory response in red-eyed treefrog larvae. We reared larvae at low, medium, and high densities with different per capita resources, environments known to produce individuals with long and short guts. We then transferred larvae to competitively equal environments to determine if longer guts provided an advantage when resources became available. We predicted that larvae from higher densities with longer guts would exhibit hyperphagia and compensatory growth. We measured growth over 1-week, as well as the time to and size at metamorphosis. To assess mechanisms underlying the growth response, we measured diet transit time and intake. Growth, development, and metamorph snout-vent length did not differ between larvae with long and short guts. Instead, different gut lengths were associated with dramatically different feeding strategies. Medium- and high-density larvae fed at rates far below what their guts could accommodate. However, the combination of low intake and longer guts extended diet transit times, presumably increasing digestibility. This unexpected strategy achieved the same results as that of low-density larvae, which ate twice as much food, but passed it more quickly through a shorter gut. The lack of a compensatory response may be attributed to the costs of accelerated growth and weak seasonal time constraints in the tropics. This suggests that although compensatory growth is widespread among animals, expression of the response may vary with environmental context. J. Exp. Zool. 323A: 778-788, 2015. © 2015 Wiley Periodicals, Inc.

Temporary tracheal occlusion in fetal sheep with lung hypoplasia does not improve postnatal lung function.

Prolonged fetal tracheal occlusion (TO) accelerates lung growth but leads to loss of alveolar epithelial type II (AE2) cells. In contrast, temporary TO leads to recovery of AE2 cells and their ability to produce surfactant. The aim of this study was to determine the effects of temporary TO in fetal sheep with lung hypoplasia on postnatal lung function, structure, and surfactant protein mRNA expression. Diaphragmatic hernia (DH) was created in 22 fetal sheep at 65 days of gestation. TO was performed between 110 days of gestation and full term (DH/TO, n = 7) and between 110 and 130 days of gestation (DH/TO+R, n = 6). Sham-operated fetuses (n = 11) served as controls. Lambs were delivered at approximately 139 days of gestation, and blood gas tensions were monitored over a 2-h resuscitation period. Temporary TO increased growth of the hypoplastic lung and restored surfactant protein mRNA expression and AE2 cell density but did not improve respiratory function above that of animals that underwent prolonged TO; DH/TO and DH/TO+R lambs were hypoxic and hypercapnic compared with Sham animals. Lung compliance remained low in DH/TO+R lambs, most likely as a consequence of the persistent increase in alveolar wall thickness in these animals.

Adenovirus-mediated ex vivo gene transfer of human vascular endothelial growth factor in a rabbit laryngotracheal reconstruction model.

Free autologous cartilage, which is used in laryngotracheal reconstruction (LTR), may undergo progressive necrosis as a result of delayed revascularization. Angiogenic growth factors, such as vascular endothelial growth factor (VEGF), promote angiogenesis in the ischemic environment. We studied the effect of ex vivo gene transfer of VEGF121 on cartilage angiogenesis and graft survival in a rabbit model of LTR. Sixty rabbits underwent LTR with auricular cartilage. The grafts were treated at 1 x 10(9) plaque-forming units with 1) VEGF121 (n = 20), 2) LacZ reporter gene (n = 20), or 3) saline solution (n = 20). Graft neovascularization and survival were histologically assayed at 1 and 10 weeks. Angiogenesis was enhanced at both 1 and 10 weeks after treatment with VEGF121 as compared to controls (p < .001). No statistical improvement in graft survival was evident after treatment with VEGF121. Ex vivo gene transfer to cartilage may be a promising gene therapy strategy to enhance revascularization--and, potentially, cartilage survival--under the proper conditions.

Risk of incomplete pyloromyotomy and mucosal perforation in open and laparoscopic pyloromyotomy.

BACKGROUND: Despite randomized controlled trials and meta-analyses, it remains unclear whether laparoscopic pyloromyotomy (LP) carries a higher risk of incomplete pyloromyotomy and mucosal perforation compared with open pyloromyotomy (OP). METHODS: Multicenter study of all pyloromyotomies (May 2007-December 2010) at nine high-volume institutions. The effect of laparoscopy on the procedure-related complications of incomplete pyloromyotomy and mucosal perforation was determined using binomial logistic regression adjusting for differences among centers. RESULTS: Data relating to 2830 pyloromyotomies (1802 [64%] LP) were analyzed. There were 24 cases of incomplete pyloromyotomy; 3 in the open group (0.29%) and 21 in the laparoscopic group (1.16%). There were 18 cases of mucosal perforation; 3 in the open group (0.29%) and 15 in the laparoscopic group (0.83%). The regression model demonstrated that LP was a marginally significant predictor of incomplete pyloromyotomy (adjusted difference 0.87% [95% CI 0.006-4.083]; P=0.046) but not of mucosal perforation (adjusted difference 0.56% [95% CI -0.096 to 3.365]; P=0.153). Trainees performed a similar proportion of each procedure (laparoscopic 82.6% vs. open 80.3%; P=0.2) and grade of primary operator did not affect the rate of either complication. CONCLUSIONS: This is one of the largest series of pyloromyotomy ever reported. Although laparoscopy is associated with a statistically significant increase in the risk of incomplete pyloromyotomy, the effect size is small and of questionable clinical relevance. Both OP and LP are associated with low rates of mucosal perforation and incomplete pyloromyotomy in specialist centers, whether trainee or consultant surgeons perform the procedure.