Autologous Reconstruction of Anomalous Origin of a Right Pulmonary Artery From the Aorta.

Anomalous origin of a pulmonary artery branch from the aorta is a rare congenital anomaly in which one of the pulmonary arteries arises from the aorta. These patients require early surgery to prevent development of severe irreversible pulmonary arterial hypertension. Multiple techniques have been described for repair of this condition. In this report, we describe a different technique compared with previously described procedures and discuss its advantages.

The so-called "one-and-a-half" ventricular repair: where are we after 40 years?

OBJECTIVES: The indications, timing, and results of the so-called "one-and-a-half ventricle repair", as a surgical alternative to the creation of the Fontan circulation, or high-risk biventricular repair, currently remain nebulous. We aimed to clarify these issues. METHODS: We reviewed a total of 201 investigations, assessing selection of candidates, the need for atrial septal fenestration, the fate of an unligated azygos vein and free pulmonary regurgitation, the concerns regarding reverse pulsatile flow in the superior caval vein, the growth potential and function of the subpulmonary ventricle, and the role of the superior cavopulmonary connections as an interstage procedure prior to biventricular repair, or as a salvage procedure. We also assessed subsequent eligibility for conversion to biventricular repair and long-term functional results. RESULTS: Reported operative mortalities ranged from 3% to 20%, depending on the era of surgical repair with 7% risk of complications due to a pulsatile superior caval vein, up to one-third incidence of supraventricular arrhythmias, and a small risk of anastomotic takedown of the superior cavopulmonary connection. Actuarial survival was between 80% and 90% at 10 years, with two-thirds of patients in good shape after 20 years. We found no reported instances of plastic bronchitis, protein-losing enteropathy, or hepatic cirrhosis. CONCLUSIONS: The so-called "one-and-a-half ventricular repair", which is better described as production of one-and-a-half circulations can be performed as a definitive palliative procedure with an acceptable risk similar to that of conversion to the Fontan circulation. The operation reduces the surgical risk for biventricular repair and reverses the Fontan paradox.

Innominate vein reconstruction in patients with bilateral superior vena cava undergoing bilateral bidirectional superior cavopulmonary anastomosis.

A 4.5-year-old patient with tricuspid atresia, pulmonary stenosis, bilateral superior vena cava veins with absent innominate vein, and hypoplasia of the left pulmonary artery required a bidirectional superior cavopulmonary anastomosis. An innominate vein was fashioned out of a 6 mm polytetrafluoroethylene graft. The technique is briefly discussed.

Long-Term Surgical Outcomes of Patients With Isomeric Right and Left Atrial Appendages.

Objectives: To compare the long-term outcomes of biventricular, univentricular, and so-called one-and-one-half ventricular repairs in patients with left and right isomerism. Methods: Surgical correction was undertaken, between 2000 and 2021, in 198 patients with right, and 233 with left isomerism. Results: The median age at operation was 24 days (interquartile range [IQR]: 18-45) and 60 days (IQR: 29-360) for those with right and left isomerism, respectively. Multidetector computed-tomographic angiocardiography demonstrated more than half of those with right isomerism had superior caval venous abnormalities, and one-third had a functionally univentricular heart. Almost four-fifths of those with left isomerism had an interrupted inferior caval vein, and one-third had complete atrioventricular septal defect. Biventricular repair was achieved in two-thirds of those with left isomerism, but under one-quarter with right isomerism (P < .001). Hazard regression for mortality revealed odds for prematurity at 5.5, pulmonary atresia at 2.81, atrioventricular septal defect with a common valvar orifice at 2.28, parachute mitral valve at 3.73, interrupted inferior caval vein at 0.53, and functionally univentricular heart with a totally anomalous pulmonary venous connection at 3.77. At a median follow-up of 124 months, the probability of survival was 87% for those with left, and 77% for those with right isomerism (P = .006). Conclusions: Multimodality imaging characterizes and delineates the relevant anatomical details, facilitating surgical management of individuals with isomeric atrial appendages. Continuing higher mortality despite surgical intervention in those with right isomerism points to the need for the reassessment of strategies for management.

Techniques and pitfalls of coronary arterial reimplantation in anatomical correction of transposition.

BACKGROUND AND AIM: We assessed the anatomical variations in coronary arterial patterns relative to the techniques of reimplantation in the setting of the arterial switch operation, relating the variations to influences on outcomes. METHODS: We reviewed pertinent published investigations, assessing events reported following varied surgical techniques for reimplantation of the coronary arteries in the setting of the arterial switch procedure. RESULTS: The prevalence of reported adverse events, subsequent to reimplantation, varied from 2% to 11%, with a bimodal presentation of high early and low late incidence. The intramural pattern continues to contribute to mortality, with some reports of 28% fatality. The presence of abnormal course relative to the arterial pedicles in the setting of single sinus origin was associated with a three-fold increase in mortality. Abnormal looping with bisinusal origin of arteries was not associated with increased risk. CONCLUSION: The techniques of transfer of the coronary arteries can be individually adapted to cater for the anatomical variations. Cardiac surgeons, therefore, need to be familiar with the myriad creative options available to achieve successful repair when there is challenging anatomy. Long-term follow-up will be required to affirm the superiority of any specific individual technique. Detailed multiplanar computed-tomographic scanning can now reveal all the variants, and elucidate the mechanisms of late complications. Coronary angioplasty or surgical revascularization may be considered in selected cases subsequent to the switch procedure.

Fontan failure: phenotypes, evaluation, management, and future directions.

OBJECTIVES: Management of "failing" and "failed" Fontan circulation, particularly the indications, timing, and type of re-intervention, currently remains nebulous. Factors contributing to pathogenesis and mortality following Fontan procedure differ between children and adults. METHODS: Since organ systems in individual patients are affected differently, we searched the extant literature for a "failing" and "failed" Fontan reviewing the clinical phenotypes, diagnostic modalities, pharmacological, non-pharmacological, and surgical techniques employed, and their outcomes. RESULTS: A total of 410 investigations were synthesised. Although proper candidate selection, thoughtful technical modifications, timely deployment of mechanical support devices, tissue-engineered conduits, and Fontan takedown have decreased the peri-operative mortality from 9 to 15% and 1 to 3% per cent in recent series, pernicious changes in organ function are causing long-term patient attrition. In the setting of a failed Fontan circulation, literature documents three surgical options: Fontan revision, Fontan conversion, or cardiac transplantation. The reported morbidity of 25% and mortality of 8-10% among Fontan conversion continue to improve in select institutions. While operative mortality following cardiac transplantation for Fontan failure is 30% higher than for other CHDs, there is no difference in long-term survival with actuarial 10-year survival of around 54%. Mechanical circulatory assistance, stem cells, and tissue-engineered Fontan conduit for destination therapy or as a bridge to transplantation are in infancy for failing Fontan circulation. CONCLUSIONS: An individualised management strategy according to clinical phenotypes may delay the organ damage in patients with a failing Fontan circulation. At present, cardiac transplantation remains the last stage of palliation with gradually improving outcomes.

Transposition physiology in the setting of concordant ventriculo-arterial connections.

BACKGROUND AND AIM: To review the anatomical details, diagnostic challenges, associated cardiovascular anomalies, and techniques and outcomes of management, including re-interventions, for the rare instances of transposition physiology with concordant ventriculo-arterial connections. METHODS: We reviewed clinical and necropsy studies on diagnosis and surgical treatment of individuals with transposition physiology and concordant ventriculo-arterial connections, analyzing also individuals with comparable flow patterns in the setting of isomerism. RESULTS: Among reported cases, just over two-thirds were diagnosed during surgery, after initial palliation, or after necropsy. Of the patients, four-fifths presented in infancy with either cyanosis or congestive cardiac failure, with complex associated cardiac malformations. Nearly half had ventricular septal defects, and one-fifth had abnormalities of the tricuspid valve, including hypoplasia of the morphologically right ventricle. A small minority had common atrioventricular junctions We included cases reported with isomerism when the flow patterns were comparable, although the atrioventricular connections are mixed in this setting. Management mostly involved construction of intraatrial baffles, along with correction of coexisting anomalies, either together or multistaged. Overall mortality was 25%, with one-fifth of patients requiring pacemakers for surgically-induced heart block. The majority of survivors were in good functional state. CONCLUSIONS: The flow patterns produced by discordant atrioventricular and concordant ventriculo-arterial connections remain an important, albeit rare, indication for atrial redirection or hemi-Mustard's procedure with bidirectional Glenn. The procedure recruits the morphologically left ventricle in the systemic circuit, producing good long-term functional results. The approach can also be used for those with isomeric atrial appendages and comparable hemodynamic circuits.

The surgical anatomy of hearts with isomeric atrial appendages-implications for surgical management.

OBJECTIVES: The most severe combinations of cardiac malformations exist in individuals having jumbled-up thoracic and abdominal organs. These patients make up 2 distinct syndromes. As yet, the consensus is lacking on how best to describe the subsets. The subsets are frequently grouped together in terms of 'heterotaxy'. The surgical approaches to the subsets, however, are markedly different. We reviewed our experiences with regard to the anatomy as observed in the autopsy room, by the analysis of computed tomographic studies, and in the operating room, to assess whether the lesions might be segregated on the basis of isomerism of the atrial appendages. METHODS AND RESULTS: A review of our findings from the examination of specimens from several archives, along with investigation of a large cohort of patients being prepared for surgical treatment, showed that individuals can uniformly be segregated into subgroups on the basis of isomeric arrangement of the atrial appendages. In all instances, this was made possible by using the criterion of the extent of the pectinate muscles within the appendages as judged relative to the atrial vestibules. Segregation on this basis, which correlated excellently with the bronchial arrangement, sets the scene for an appropriate description of the remainder of the heart, providing the cardiac surgeon with all the inferences required for appropriate surgical intervention. CONCLUSIONS: When assessing individuals having the features of so-called 'heterotaxy', it is possible to segregate the groups into subsets of individuals having either isomeric right or left atrial appendages. This approach provides the framework for the assessment of appropriate surgical management.

A reassessment of the anatomical features of multiple ventricular septal defects.

BACKGROUND: Over the course of time, new developments associated with the embryogenesis of the murine heart have served to clarify the developmental processes observed in the human heart. This evidence allows for the creation of a developmental framework for many congenital cardiac defects. AIMS: We aim to solidify the framework related to the categorization of both solitary and multiple ventricular septal defects. MATERIALS AND METHODS: Mice having genetic perturbation of the Furin enzyme have demonstrated perimembranous and juxta-arterial ventricular septal defects, permitting the inference to be made that these defects can co-exist with defects occurring within the apical muscular septum. RESULTS: Basis of developmental evidence, furthermore, all interventricular communications can be placed into one of three groups, namely those which are perimembranous, juxta-arterial, and muscular. All of the defects are described based on their borders as seen from the morphologically right ventricle. Our focus here will be on those defects within the muscular ventricular septum, recognizing that such defects can co-exist with those that are perimembranous. We discuss the differentiation of multiple discrete defects from those referred to as the "Swiss cheese" variant. CONCLUSIONS: As we show, appropriate surgical management requires an understanding of the specific terminology, as the surgical approach may differ depending on the combination of the individual defects. Data from the Society for Thoracic Surgeons revealed that both mortality and morbidity were increased in the setting of multiple as opposed to solitary ventricular septal defects.

A review of the therapeutic management of multiple ventricular septal defects.

BACKGROUND AND AIM: We showed in our anatomical review, ventricular septal defects existing as multiple entities can be considered in terms of three major subsets. We address here the diagnostic challenges, associated anomalies, the role and techniques of surgical instead of interventional closure, and the outcomes, including reinterventions, for each subset. METHODS: We reviewed 80 published investigations, noting radiographic findings, and the results of clinical imaging elucidating the location, number, size of septal defects, associated anomalies, and the effect of severe pulmonary hypertension. RESULTS: Overall, perioperative mortality for treatment of residual multiple defects has been cited to be between 0% and 14.2%, with morbidity estimated between 6% and 13%. Perioperative mortality is twice as high for perimembranous compared to muscular defects, with the need for reoperation being over four times higher. Perventricular hybrid approaches are useful for the closure of high anterior or apical defects. Overall, the results have been unsatisfactory. Pooled data reveals incidences between 2.8% and 45% for device-related adverse events. Currently, however, outcomes cannot be assessed on the basis of the different anatomical subsets. CONCLUSIONS: We have addressed the approaches, and the results, of therapeutic treatment in terms of coexisting discrete defects, the Swiss-cheese septum, and the arrangement in which a solitary apical muscular defect gives the impression of multiple defects when viewed from the right ventricular aspect. Treatment should vary according to the specific combination of defects.

A reappraisal of the sinus venosus defect.

OBJECTIVES: The phenotypic features and morphogenesis of the 'sinus venosus defect' remain controversial. The phenotypic features are anomalous systemic connections of 1 or more pulmonary veins that retain their left atrial connection, usually associated with a biatrial connection of the superior caval vein. Cases with these features, however, have not always been described as sinus venosus defects. METHODS: We reviewed the findings documented in the literature from 11 patients with a biatrial connection of the superior caval vein, most reported following an autopsy examination. We compared these findings with the anatomical details of 50 patients undergoing surgical correction in our centre, paying particular attention to the override of the superior caval vein. RESULTS: In only two-thirds of those undergoing surgery did the superior caval vein override the rims of the oval fossa, with the degree of override >50% in only 2 individuals. It is only these latter 2 cases that are directly comparable to the reported cases of biatrial connection of the superior caval vein. CONCLUSIONS: Our comparisons provide new insights into the developmental background and phenotypic features of the superior sinus venosus defect. The defects exist because of the anomalous systemic connection of the pulmonary veins that retain their left atrial connections but not always in association with a biatrial connection of the superior caval vein. In extreme cases, nonetheless, they can underscore the connection of the caval vein to the morphologically left atrium, frequently described previously as a 'biatrial connection'. The sinus venosus defect is better considered a venovenous malformation than a septal defect.

Right pulmonary artery to left atrium fistula.

In this report, we describe a 25-year-old patient in whom a fistula between the right pulmonary artery and the left atrium was accurately diagnosed. The successful surgical management of this patient is described. Current diagnostic methods, evaluation, and treatment options for this uncommon cause of cyanosis in an adult patient are discussed.

Surgical management of lesions encountered in the setting of the retroaortic left brachiocephalic vein.

BACKGROUND AND AIM: Although the retroaortic left brachiocephalic vein in isolation is of no clinical importance, its recognition in the setting of associated lesions is important. We sought to address issues concerning the influence of isomerism, the establishment of diagnosis, and its importance in various surgical and interventional procedures. METHODS: A total of 80 published clinical and necropsy studies in the setting of a retroaortic left brachiocephalic vein described 250 patients. Clinical presentation, radiographic, ultrasonographic findings, contrast echocardiography, computed-tomographic angiocardiography, magnetic resonance imaging, and angiocardiography provided the diagnostic information prior to considering the surgical approach to the associated cardiac anomalies. RESULTS: Among 250 reported cases, three-quarters had associated congenitally malformed hearts. Of these 189 patients, all but seven had usual atrial arrangement. Right isomerism was reported in five patients and two patients having left isomerism. Almost two-thirds had tetralogy of Fallot or its variants, over four-fifths had malformations involving the outflow tract, two-thirds had a right aortic arch with two patients having a cervical aortic arch, and onepatient had double aortic arch. Various innovative individualized surgical procedures were employed with an overall perioperative mortality of 3.4%. CONCLUSIONS: Although the retroaortic left brachiocephalic vein is asymptomatic, its recognition during clinical investigation should raise the possibility of an association with other malformations, especially right aortic arch, ventricular septal defect, and anomalies of the outflow tracts. We submit that an increased appreciation of this venous anomaly may facilitate surgical planning, endovascular procedures, placement of central venous lines, and transvenous pacemakers.

Surgical management of divided atrial chambers.

BACKGROUND AND AIM: The morphological variations when one, or both, of the atrial chambers is subdivided, are many and varied. We sought to address clinical presentations, potentially misdiagnosed cases, diagnostic modalities, surgical approaches, and outcomes of this "family" of uncommon lesions. METHODS: A total of 193 published investigations were synthesized. Diagnostic information was provided by clinical presentation, and multimodality imaging studies. RESULTS: Almost three-quarters of patients with divided atrial chambers present during infancy with severe pulmonary hypertension and cardiac failure. Associated cardiac and extra-cardiac defects are present in between half and nine-tenths of cases. Acquired division of the left atrium has been reported after the Fontan operation, orthotopic cardiac transplantation, and complicated aortic valvar infective endocarditis. Surgery under cardiopulmonary bypass remains the definitive treatment. Balloon dilation may be considered in anatomically compatible variants in the setting of cardiac failure and pregnancy as a bridge todefinitive treatment. Overall, mortality has been cited between nil to 29%. Presentation during infancy, associated congenital anomalies, pulmonary hypertension, and surgery in the previous era, have been the reported causes of death. The operative survivors have long-term favourable outcomes, with near normal cardiac dimensions and low risk of recurrence. While asymptomatic patients with division of the right atrium do not need treatment, surgical resection of the dividing partition under cardiopulmonary bypass is recommended in symptomatic patients with complex anatomy, the spinnaker malformation, or associated cardiac anomalies. Balloon dilation may be considered in uncomplicated patients with less obstructive lesions. Hybrid intervention and endoscopic robotic correction also have been performed. CONCLUSIONS: Resection of the dividing shelf allows the survivors to regain near normal dimensions with a low risk of recurrence. We submit that an increased appreciation of the anatomic background to division of the atrial chambers will contribute to improved surgical management.

Surgical management of the scimitar syndrome.

BACKGROUND AND AIM: We sought to address the varied anatomical details, the diagnostic challenges, associated cardiopulmonary anomalies, the techniques, and outcomes of management, including re-interventions of scimitar syndrome. METHODS: A total of 92 published investigations of scimitar syndrome were reviewed. Diagnostic information was provided by clinical presentations, radiographic findings, transthoracic and transesophageal echocardiography, computed-tomographic angiography, magnetic resonance imaging, angiocardiography, and ventilation/perfusion scans. These investigations served to elucidate the origin, course, and termination of the scimitar vein, the intracardiac anatomy, the presence of associated defects, and the patterns of any accompanying pulmonary lesions prior to surgical intervention. RESULTS: Of the patients described, up to four-fifths presented during infancy, with cardiac failure, increased pulmonary flow, and pulmonary hypertension. Associated cardiac and extracardiac defects, particularly hypoplasia of the right lung, are present in up to three-quarters of cases. Overall operative mortality has been cited between 4.8% and 5.9%. Mortality was highest in patients with preoperative pulmonary hypertension, and those undergoing surgery in infancy. Despite timely surgical intervention, post-repair obstruction of the scimitar vein, intra-atrial baffle obstruction, or stenosis of the inferior caval vein were reported in up to two-thirds of cases. The venous obstruction could not be related to any particular surgical technique. On long term follow-up, one sixth of patients reported persistent dyspnoea and recurrent respiratory infections. CONCLUSIONS: Any infants presenting with heart failure, right-sided heart, and hypoplastic right lung should be evaluated to exclude the syndrome. An increased appreciation of variables will contribute to improved surgical management.

Totally anomalous pulmonary venous connection with intact atrial septum.

BACKGROUND: Total anomalous pulmonary venous connection with intact interatrial septum is extremely rare. AIMS: In these patients, a right to left shunt through a ventricular septal defect or a patent ductus arteriosus is mandatory to maintain the systemic circulation. Mechanical or physiological restriction of shunting through these pathways results in rapid clinical deterioration. DISCUSSION: We describe the anatomical findings with surgical repair in one such 10-day-old baby.

A Review of the Surgical Management of Aorto-ventricular Tunnels.

We present a synthesis of 95 published investigations of the exceedingly rare tunnels that can exist between the aortic root and the left or right ventricles. From the 220 suitable cases included in these investigations, we reviewed the clinical presentations, modalities used for diagnosis, surgical approaches, and outcomes. Diagnostic information was provided by clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, magnetic resonance imaging, cardiac catheterization, and angiocardiography. These techniques elucidated the coronary arterial origins and associated defects and defined the disease before surgery. Patients occasionally present with an asymptomatic cardiac murmur and cardiomegaly, but most suffer cardiac failure in the first year of life when the tunnel enters the left ventricle. Antenatal diagnosis by fetal echocardiography is reliable after 18 weeks of gestation. Associated defects, involving the proximal coronary arteries or the aortic or pulmonary valves, are present in nearly half the cases. Prompt diagnosis and surgical repair are important for a favorable outcome. Overall, operative mortality has been cited to be between 3% and 8.3%. Associated congenital coronary arterial anomalies, residual severe aortic stenosis, poor left ventricular function, and rupture of an infected suture line have been the reported causes of death. Despite early surgical intervention, an incidence of 16% to 60% postoperative residual aortic regurgitation of varying severity has been reported. The requirement of further repair or replacement of the aortic valve ranges from 0% to 50%. We submit that an increased appreciation of these details relative to the tunnels will contribute to improved surgical management.

Total Pericardiectomy Using a Modified Left Anterolateral Thoracotomy Without Cardiopulmonary Bypass.

BACKGROUND: We sought to ascertain the short- and long-term results of total pericardiectomy for chronic constrictive pericarditis using a modified left anterolateral thoracotomy without cardiopulmonary bypass on postoperative low cardiac output, normalization of intracardiac pressures, survival, and reoperations. METHODS: Between January 2005 and December 2019 a series of 127 consecutive patients (91 male patients) between ages 4 and 72 years (median, 25 years; interquartile range, 18-38) underwent radical total pericardiectomy using a modified left anterolateral thoracotomy without cardiopulmonary bypass. RESULTS: Operative and late mortalities were 3.1% and 1.6%, respectively. Thirty-one patients (24.4%) had postoperative low cardiac output, and none required reoperations. At a median follow-up of 99 months (interquartile range, 56-141) the actuarial survival was 97.6% ± 0.01% months (95% confidence interval, 92.8-99.2). At their last follow-up 113 (93.4%) and 8 (6.6%) survivors were in New York Heart Association class I and II, respectively. CONCLUSIONS: Total pericardiectomy is associated with lower perioperative and late mortality and decreased low cardiac output syndrome and confers significant long-term advantage of superior hemodynamics.

Long-Term Outcomes of the Double-Barrel Technique for Superior Sinus Venosus Defect With Partially Anomalous Pulmonary Venous Connection.

BACKGROUND: Repair of superior sinus venosus defect with high partially anomalous pulmonary venous connection (PAPVC) using an intracardiac baffle may be complicated by systemic or pulmonary venous pathway obstruction and sinus nodal dysfunction (SND). Our surgical strategy for repair of all types of superior sinus venosus defect has evolved chiefly to avoid the abovementioned complications and preserving the growth potential of the superior cavoatrial junction. METHODS: Between 2007 and 2019, fifty consecutive patients aged 2 to 60 (mean, 17.6±16.7) years underwent repair of superior sinus venosus defect using the double-barrel technique as described. The anomalous pulmonary veins drained into the superior cavoatrial junction in 17 patients and more than 2 cm above the cavoatrial junction in 33 patients. RESULTS: There were no early or late deaths and no reoperations. At a mean follow-up of 103.9 (±50.2) months, all survived the operation, and actuarial freedom from SND was 97.9% (±standard error, 0.02%; 95% CI: 0.86-0.99). No patient had systemic or pulmonary venous pathway obstruction. A permanent pacemaker was required in one (2%) patient for sick sinus syndrome. CONCLUSIONS: The double-barrel method is an expedient, safe, and effective technique in superior sinus venosus defect. It provides dual drainage of superior vena cava preserving the superior cavoatrial junction without causing systemic or pulmonary venous pathway obstruction and can be utilized in all cases including those with high PAPVC. Preservation of the cavoatrial junction and use of autogenous atrial tissue for systemic venous pathway avoids SND and preserves growth potential.

A Review of the Surgical Management of Anomalous Connection of the Right Superior Caval Vein to the Morphologically Left Atrium and Biatrial Drainage of Right Superior Caval Vein.

The present perspective is a synthesis of published investigations in the setting of anomalous connection of the right superior caval vein to the morphologically left atrium or biatrial drainage of the right caval vein. We identified 57 suitable cases from 97 investigations, reviewing the clinical presentation, diagnostic modalities utilized, surgical techniques used, and their outcomes. Clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, radionuclide perfusion scan, magnetic resonance imaging, and angiocardiography provided the diagnostic information and were used to define the disease entities before surgery. We have also addressed several issues concerning the influence of the so-called heterotaxy: the establishment of the diagnosis, the variation in clinical presentation, and subsequent management. For the overall group of patients undergoing either surgical intervention or transcatheter treatment with an Amplatzer vascular plug, the operative mortality remains high at 9.5%. We submit that an increased appreciation of these disease entities will contribute to improved future surgical management.