Evolving Trends Towards Minimally Invasive Surgery for Solid-Pseudopapillary Neoplasms

Outcome and survival were similar with laparoscopic and open pancreatectomy in 102 solid pseudopapillary neoplasms

BACKGROUND

Solid pseudopapillary neoplasms of the pancreas (SPNP) are rare tumors predominantly in young women. We report the largest single-center cohort study comparing resection of SPNP by laparoscopic approach (LA) and the open approach (OA).

METHOD

Between 2001 and 2021, 102 patients (84% women, median age: 30) underwent pancreatectomy for SPNP and were retrospectively studied. Demographic, perioperative, pathological, early and the long-term results were evaluated between patients operated by LA and those by OA.

RESULTS

Population included 40 LA and 62 OA. There were no significant differences in demographics data between the groups. A preoperative biopsy by endoscopic ultrasound was performed in 45 patients (44%) with no difference between the groups. Pancreatoduodenectomy (PD) was less frequently performed by LA (25 vs 53%, p = 0.004) and distal pancreatectomy (DP) was more frequently performed by LA (40 vs 16%, p = 0.003). In the subgroup analysis by surgical procedure, LA-PD was associated with one mortality, less median blood loss (180 vs 200 ml, p = 0.034) and fewer harvested lymph nodes (11 vs 15, p = 0.02). LA-DP was associated with smaller median tumor size on imaging (40 vs 80mm, p = 0.048), shorter surgery (135 vs 190 min, p = 0.028), and fewer complications according to the median comprehensive complication index score (0 vs 8.7, p = 0.048). LA-Central pancreatectomy was associated with shorter surgery (160 vs 240, p = 0.037), less median blood loss (60 vs 200, p = 0.043), and less harvested lymph nodes (5 vs 2, p = 0.025). After a median follow-up of 60 months, two recurrences (2%) were observed and were unrelated to the approach.

CONCLUSIONS

The LA for SPNP appears to be safe, should be applied cautiously in case of PD for large lesion, and was not associated with recurrence.

Development of a nomogram for predicting the high-risk groups of solid-pseudopapillary neoplasms of the pancreas

Background

Solid pseudopapillary neoplasms (SPNs) of the pancreas are indolent rare tumors with malignant potential. The risk factors associated with the malignant behavior of SPNs are still unclear.

Methods

A retrospective analysis of patients with SPNs who underwent surgical treatment in the First Hospital of Jilin University from January 2010 to January 2022 was conducted. The clinical baseline data, pathology, imaging, and laboratory indicators of the patients were analyzed by univariate and multivariate logistic regression to identify the independent risk factors associated with the high-risk groups, and a predictive model was established in the form of a nomogram.

Results

In multivariate analysis, clinical symptoms (P < 0.001), unclear tumor margins (P = 0.001), incomplete tumor capsules (P = 0.005), maximum tumor diameters ≥ 7.2 cm (P = 0.003), and prognostic nutritional index values < 47.45 (P = 0.007) were independent risk factor for SPNs with high-risk groups. A nomogram model was successfully established to predict high-risk groups of SPNs. The area under the receiver operating characteristic curve was 0.856. The calibration prediction curve was in good agreement with the standard curve.

Conclusion

The nomogram model based on clinical symptoms, inflammatory markers, and imaging features had a high application value in the preoperative prediction of the high-risk groups of SPNs. A novel nomogram of the affiliated hospital of Jilin University-SPNs risk model was proposed for routine application to guide the patient counseling in clinical practice.

Robotic Parenchymal-Sparing Pancreatectomy: A Systematic Review

BACKGROUND

Parenchymal-sparing approaches to pancreatectomy are technically challenging procedures but allow for preserving a normal pancreas and decreasing the rate of postoperative pancreatic insufficiency. The robotic platform is increasingly being used for these procedures. We sought to evaluate robotic parenchymal-sparing pancreatectomy and assess its complication profile and efficacy.

METHODS

This systematic review consisted of all studies on robotic parenchymal-sparing pancreatectomy (central pancreatectomy, duodenum-preserving partial pancreatic head resection, enucleation, and uncinate resection) published between January 2001 and December 2022 in PubMed and Embase.

RESULTS

A total of 23 studies were included in this review (n = 788). Robotic parenchymal-sparing pancreatectomy is being performed worldwide for benign or indolent pancreatic lesions. When compared to the open approach, robotic parenchymal-sparing pancreatectomies led to a longer average operative time, shorter length of stay, and higher estimated intraoperative blood loss. Postoperative pancreatic fistula is common, but severe complications requiring intervention are exceedingly rare. Long-term complications such as endocrine and exocrine insufficiency are nearly nonexistent.

CONCLUSIONS

Robotic parenchymal-sparing pancreatectomy appears to have a higher risk of postoperative pancreatic fistula but is rarely associated with severe or long-term complications. Careful patient selection is required to maximize benefits and minimize morbidity.

Solid pseudopapillary neoplasms of the pancreas: Is there a factor determining the prognosis? Experience of a single institution

Solid pseudopapillary neoplasms (SPNs) are frequently seen in young women. Although the behavior pattern varies, these rare lesions generally have a low malignant potential. In this study, the aim was to investigate the effect of clinicopathological features of lesions on the recurrence in and survival of patients. In this study, patients of our clinic who were pathologically diagnosed with SPN after pancreatic surgery between July 2008 and December 2020 were evaluated retrospectively. Patients' age, gender, comorbidities, symptoms at the time of application, preoperative CA 19-9, CEA value, preoperative cross-sectional diagnostic imaging method and lesion characteristics, surgery, postoperative complications, length of hospital stay, and histopathological features were evaluated. Early and late mortality, overall survival, disease-free survival, and recurrence rate were determined. Four of the 23 patients diagnosed with SPN were male and the median age was 29 (23-47) years. Of the study patients, 69.56% experienced pain symptoms and 30.43% were asymptomatic. The median tumor size was 4 cm (1.5-15). The most common surgical procedure was distal pancreatectomy (56.5%). The median length of hospital stays was 5 (3-120) days and morbidity was observed in 9 cases (39.13%). The mortality rate was 4.35%. The mean follow-up period in the series was 53 (8-132) months and none of the patients developed recurrence. In this study, no significant difference was found regarding recurrence in patients with SPN with histopathologically aggressive biological behavior. The overall survival rate was 95.7%. SPNs are rare lesions with low malignant potential. SPNs are associated with longer-term survival after surgical resection.

Prospects and applications of enucleation in solid pseudopapillary neoplasms of the pancreas

Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare, low-grade, malignant neoplasms that are mostly seen in young women in the second and third decades of life and are quite uncommon in children. Standard resection for benign and borderline neoplasms of the pancreas is associated with a substantial risk of postoperative morbidity and long-term functional impairment, whereas enucleation leads to less morbidity and preserves healthy parenchyma as well as exocrine and endocrine function. Enucleation of SPNs has been increasingly reported to be feasible and safe for preserving the normal physiological function of the pancreas, especially in teenagers and children. This review summarizes findings published in recent years on the enucleation of SPNs as well as potential future developments and directions. Enucleation has undoubtedly come to stay as an alternative surgical procedure for SPNs. However, many questions remain unresolved, and future directions toward the best surgical indication, the prevention and intervention of complications, especially pancreatic fistula, intraoperative resection margin safety assessment, and long-term oncology prognosis remain to be evaluated and should be explored in future clinical trials.

Laparoscopic Resection of Pediatric Solid Pseudopapillary Tumors of the Pancreas

BACKGROUND

Solid pseudopapillary tumors (SPTs) of the pancreas arise rarely in children, are often large, and can associate intimately with splenic vessels. Splenic preservation is a fundamental consideration when resecting distal SPT. Occasionally, the main splenic vessels must be divided to resect the SPT with negative margins, but the spleen can be preserved if the short gastric vessels remain intact (ie, Warshaw procedure). The purpose of this study was to evaluate outcomes of distal pancreatectomy (DP) for SPT in children and to highlight 2 cases of splenic preservation using the Warshaw procedure.

METHODS

Patients 19 years and younger who were treated at a single children's hospital between July 2004 and January 2021 were examined. Patient characteristics were collected from the electronic medical record. A pediatric radiologist calculated SPT and pre- and post-operative (ie, non-infarcted) splenic volumes.

RESULTS

Eleven patients received DP for SPT. Six DPs were performed open and 5 laparoscopically. The spleen was preserved in 3 open and 4 laparoscopic DPs. A laparoscopic Warshaw procedure was performed in 2 patients. Laparoscopic resection associated with less frequent epidural use (P = .015), shorter time to full diet (P = .030), and post-operative length of stay (P = .009), compared to open resection. Average residual splenic volume after the laparoscopic Warshaw procedure was 70% of preoperative volume.

DISCUSSION

Laparoscopic DP for pediatric SPT achieved similar oncologic goals to open resection. Splenic preservation was feasible with laparoscopy in most cases and was successfully supplemented with the Warshaw procedure, which has not been previously reported for SPT resection in children.

Minimally invasive distal pancreatectomy and the cost of conversion

BACKGROUND

Minimally invasive surgery (MIS) is preferred for distal pancreatectomy but is not always attempted due to the risk of conversion to open. We hypothesized that the total cost for MIS converted to open procedures would be comparable to those that started open.

METHODS

A prospectively collected institutional registry (2011-2017) was reviewed for demographic, clinical, and perioperative cost data for patients undergoing distal pancreatectomy.

RESULTS

There were 80 patients who underwent distal pancreatectomy: 41 open, 39 MIS (11 laparoscopic and 28 robotic). Conversion to open occurred in 14 of 39 (36%, 3 laparoscopic and 11 robotic). Length of stay was shorter for the MIS completed (6 days; range, 3-8), and MIS converted to open (7 days; range, 4-10) groups, compared with open (10 days; range, 5-36; P = .003). Laparoscopic cases were the least expensive (P = .02). Robotic converted to open procedures had the highest operating room cost. However, the total cost for robotic converted to open cohort was similar to the open cohort due to cost savings associated with a shorter length of stay.

CONCLUSIONS

Despite the higher intraoperative costs of robotic surgery, there is no significant overall financial penalty for conversion to open. Financial considerations should not play a role in selecting a robotic or open approach.

Systematic Review and Meta-analysis of Minimally Invasive Pancreatectomies for Solid Pseudopapillary Neoplasms of the Pancreas

OBJECTIVES

We report the first systematic review and meta-analysis on minimally invasive pancreatectomy (MIP) for solid pseudopapillary neoplasms (SPPN) of the pancreas.

METHODS

A systematic review of all studies reporting patient characteristics and outcomes of MIP for SPPN was conducted.

RESULTS

We reviewed 27 studies comprising 149 patients with SPPN managed via MIP. Five were comparative retrospective cohort studies, comprising 46 and 60 patients in the minimally-invasive and open groups, respectively. Tumor size was smaller in the minimally-invasive group (mean difference, -2.20; 95% confidence interval (CI), -3.09 to -1.32; P < 0.001). The MI group had lower intraoperative blood loss (mean difference, -180.19; 95% CI, -344.28 to -16.09; P = 0.03) and transfusion requirement (relative risk, 0.24; 95% CI, 0.06-0.94; P = 0.04), and a shorter time to diet (mean difference, -2.99; 95% CI, -3.96 to -2.03; P < 0.001) and length of stay (mean difference, -3.61; 95% CI, -6.98 to -0.24; P = 0.04). There was no significant difference in operating time, margin positivity, postoperative morbidity, and postoperative pancreatic fistula rates.

CONCLUSIONS

Minimally invasive pancreatectomy for SPPN is associated with decreased intraoperative blood loss and transfusion requirements and a shorter postoperative time to diet and hospital stay.

Outcome of minimally-invasive versus open pancreatectomies for solid pseudopapillary neoplasms of the pancreas: A 2:1 matched case-control study

Backgrounds/Aims

Solid pseudopapillary neoplasm (SPPN) is typically seen in young healthy females who would likely benefit from minimally-invasive pancreatectomy (MIP). A few comparative studies have suggested that MIP is associated with favorable outcomes when compared to the open approach for SPPN. This study aims to mitigate potential selection bias by performing a matched case-control study comparing MIP vs open pancreatectomy (OP) for SPPN.

Methods

We performed a single-institution retrospective electronic chart review of all patients who underwent surgery for pathologically confirmed SPPN between 2000 and 2017. A 2:1 matched comparison using age, gender, tumor size and the type of pancreatectomy was performed between OP and MIP.

Results

A total of 40 patients with a median age of 40.3 years (range 16.5-64.4) and female sex predominance (n=34, 85.0%) underwent surgery during the study period. Nine patients underwent MIP. Matched comparison between 18 OP and 9 MIP demonstrated that MIP was associated with a longer median operating time (305 vs 180 min, p=0.046) and shorter median postoperative stay (6 vs 9 days, p=0.015). There were no significant differences in intraoperative blood loss, blood transfusion requirements, postoperative morbidity (including postoperative pancreatic fistula) and mortality, resection margins, lymph node yield and long-term survival.

Conclusions

MIP is a safe and viable option in the management of SPPN with the benefit of a shorter postoperative length of stay at the expense of a longer operation time. There was no significant difference in oncologic outcomes between both groups of patients.

Robotic pancreatectomy for solid pseudopapillary tumors in the pancreatic head: A propensity score-matched comparison and analysis from a single center

BACKGROUND

Robotic surgery is the most advanced minimally invasive technique for the treatment of complicated solid pseudopapillary tumors (SPT). The aim of this study is to evaluate feasibility of robotic surgery for the treatment of SPTs in the pancreatic head.

METHODS

A retrospective analysis of the clinical data of 83 SPTs in pancreatic head was conducted. Clinical characteristics were extracted and propensity score matching (PSM) was used to compare and evaluate mid-term outcomes of the two techniques.

RESULTS

Pancreaticoduodenectomy (PD), duodenum-preserving partial pancreatic head resection (DPPHR-P) and tumor enucleation (En) were performed in 51, 24, and 8 patients, respectively. The robotic approach was associated with a significantly lower volume of blood loss, lower need for transfusion, and faster time to post-surgery recovery. Major complications and costs were comparable for both techniques.

CONCLUSION

A robotic approach provides an alternative to open surgery for SPTs in the pancreatic head without increasing the incidence of clinically relevant pancreatic fistula (CRPF) or other major complications and with good patient outcomes.

Differentiation of aggressive from non-aggressive pancreatic solid pseudopapillary neoplasms using computed tomography

PURPOSES

Microscopic aggressive behaviors may be related with the prognosis of solid pseudopapillary neoplasms (SPNs). In this study, we investigate computed tomography (CT) features and differential diagnosis of aggressive and non-aggressive SPNs in pancreas.

MATERIALS AND METHODS

122 patients with pathologically proven SPNs in pancreas were included. Patients' age, tumor site, texture, shape, margins, exophytic growth, capsule, calcification, hemorrhage, pancreatic duct dilatation or pancreatic parenchyma atrophy, peripancreatic infiltration or metastases, vascular encasement, and enhancement pattern were assessed. The diagnostic accuracy was analyzed by using the receiver operating characteristic curve (ROC).

RESULTS

There were 30 aggressive SPNs and 92 non-aggressive SPNs. Aggressive SPNs showed significantly higher frequencies of an ill-defined margin, patient age > 40.5 years, and tumor size < 42.1 mm, but lower frequencies of complete capsule, hemorrhage compared with non-aggressive SPNs (p < 0.05). Lack of complete capsule and age > 40.5 years were independent risk factors of aggressive SPNs (odd ratio 7.08 and 3.1, respectively). When we applied the two predictors in the logistic regression model, the area under the curve (AUC) was 0.77 with sensitivity of 86.7% and specificity of 55.4%.

CONCLUSION

Size less than 42.1 mm, lack of complete capsule, ill-defined, and absent bleeding are useful CT imaging features for predicating aggressive SPNs. Patient age > 40.5 years and lack of complete capsule showed acceptable diagnostic performance for discriminating aggressive from non-aggressive SPNs.

Clinicopathological Features and Treatment Outcomes of Solid Pseudopapillary Neoplasms of the Pancreas: A 10-Year Case Series from a Single Center

Background: Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare pancreatic tumors. This study summarizes the clinicopathological characteristics and treatment outcomes of SPN patients through a 10-year single-center case series. Materials and Methods: Medical records of patients diagnosed with SPNs and who underwent surgery between August 2007 and July 2017 at Qilu Hospital, Shandong University, were retrospectively analyzed. Results: This study included 91 patients: 13 males/78 females, mean age 28.8 ± 11.5 years. Among the cases, 38.5% were incidentally confirmed without specific symptoms, while the others displayed various abdominal symptoms. All patients had single pancreatic lesions, and 1 patient presented with liver metastasis. Abdominal enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasound were the diagnostic imaging techniques used to identify SPNs. All patients had successful surgical removal of their tumors; 28 patients underwent laparoscopy. During the 2-121-month follow-up period, 1 patient died of lung metastasis and multiple organ failure at 35 months postoperatively, but no other tumor recurrence or metastasis was found. Conclusions: SPN usually occurs in the young female population and presents with various clinical characteristics. Mixed solid-cystic masses with calcification or hemorrhage are typical morphological tumor features. Minimally invasive organ-/function-preserving operations are advocated for benign cases, while aggressive radical resection should be performed in patients with local invasion or distant metastasis.

Survival and Prognostic Factors in Patients With Solid Pseudopapillary Neoplasms of the Pancreas

OBJECTIVES

Prognostic factors for solid pseudopapillary neoplasms (SPN) of the pancreas have been incompletely defined in the literature. We aimed to use the National Cancer Database to describe survival and characterize prognostic factors in patients with pancreatic pseudopapillary neoplasms.

METHODS

We identified 304 patients with pancreatic SPN diagnosed between 2004 and 2012 using the National Cancer Database. All patients were included in the survival analysis. Kaplan-Meier method, χ, and log-rank tests were used for statistical analysis. Cox proportional hazard regression model was used for multivariate analysis.

RESULTS

The median age at diagnosis was 36.5 years. Eighty-five percent of patients were female, 69% were white, and 25% were black. Metastases were observed in 5% of patients. Median tumor size was 5.1 cm. Ninety-two percent of patients underwent primary tumor resection. At 60 months, 98% of patients who underwent resection were alive, and 40% who did not undergo resection were alive. On multivariate analysis, female sex, resection of primary tumor, and absence of metastasis were correlated with improved survival.

CONCLUSIONS

Patients with SPN who undergo resection have an excellent survival at 5 years. Surgery should be considered in all patients with this diagnosis.

Enucleation of pancreatic solid pseudopapillary neoplasm: Short-term and long-term outcomes from a 7-year large single-center experience

BACKGROUND

Enucleation is increasingly used for pancreatic solid pseudopapillary neoplasm (SPN) to preserve function of the pancreas. The data was limited due to rarity of this low-grade neoplasm. We sought to describe the indications, operative technique, short and long-term outcomes after enucleation with largest series of enucleated SPNs.

METHODS

Data collected retrospectively from 110 patients with SPN who underwent pancreatectomy between 2009 and 2016 in our institution were reviewed. Thirty-one patients underwent enucleation were identified for analysis, and compared with the 70 patients underwent conventional pancreatic resection.

RESULTS

Of the 31 patients, 27 (87.1%) were women, and the mean age was 29.8 years (range, 11-49 years). Enucleated SPNs were mostly located in the head/uncinate process of the pancreas (38.7%). Overall morbidity was 25.8%, mainly due to POPF (19.4%), and severe morbidity was only 6.5% with no death. Compared with conventional pancreatic resection, enucleation had a shorter duration of surgery (P < 0.001), less blood loss (P < 0.001), lower rate of exocrine insufficiency (P = 0.033) and comparable morbidity (P = 1), with no increased risk of tumor recurrence (P = 1). The rate of endocrine insufficiency after enucleation seemed lower (Nil vs. 4.5%, P = 0.55).

CONCLUSIONS

Enucleation of SPN of the pancreas appears to be feasible and safe for preserving exocrine and endocrine function of the gland. Enucleation with negative surgical margin seems adequate with no increased risk of tumor recurrence. Enucleation could be seriously considered as an alternative to conventional resection for this frequently young population.

Minimally invasive surgical approaches offer earlier time to adjuvant chemotherapy but not improved survival in resected pancreatic cancer

BACKGROUND

Pancreatic surgery encompasses complex operations with significant potential morbidity. Greater experience in minimally invasive surgery (MIS) has allowed resections to be performed laparoscopically and robotically. This study evaluates the impact of surgical approach in resected pancreatic cancer.

METHODS

The National Cancer Data Base (2010-2012) was reviewed for patients with stages 1-3 resected pancreatic carcinoma. Open approaches were compared to MIS. A sub-analysis was then performed comparing robotic and laparoscopic approaches.

RESULTS

Of the 9047 patients evaluated, surgical approach was open in 7511 (83%), laparoscopic in 992 (11%), and robotic in 131 (1%). The laparoscopic and robotic conversion rate to open was 28% (n = 387) and 17% (n = 26), respectively. Compared to open, MIS was associated with more distal resections (13.5, 24.3%, respectively, p < 0.0001), shorter hospital length of stay (LOS) (11.3, 9.5 days, respectively, p < 0.0001), more margin-negative resections (75, 79%, p = 0.038), and quicker time to initiation of chemotherapy (TTC) (59.1, 56.3 days, respectively, p = 0.0316). There was no difference in number of lymph nodes obtained based on surgical approach (p = 0.5385). When stratified by type of resection (head, distal, or total), MIS offered significantly shorter LOS in all types. Multivariate analysis demonstrated no survival benefit for any MIS approach relative to open (all, p > 0.05). When adjusted for patient, disease, and treatment characteristics, TTC was not an independent prognostic factor (HR 1.09, p = 0.084).

CONCLUSION

MIS appears to offer comparable surgical oncologic benefit with improved LOS and shorter TTC. This effect, however, was not associated with improved survival.

Image Findings of Solid Pseudopapillary Neoplasms of the Pancreas on Multiphasic Multidetector CT Scan-A Single Institute Experience from Southern India

Introduction

Solid Pseudopapillary Neoplasms (SPN) are uncommon pancreatic tumours and are slow growing with uncertain malignant potential, showing female preponderance. Postoperative prognosis is good and metastasis is rare.

Aim

To summarise the imaging and pathological features of seven cases of SPN in three years period, from January 2013 to January 2016.

Materials and Methods

In this retrospective study the imaging features of seven cases on triphasic multidetector Computed Tomogram (CT), a 16-slice scanner, were reviewed along with CT-guided Fine Needle Aspiration Cytology (FNAC) and histopathological examination. Statistics were expressed in terms of percentiles.

Results

All cases were female patients with an age range of 13-35 years (mean: 23.3 years). On CT assessment, the size of the tumours varied from 2.5-14 cm (mean: 5.3 cm). All these tumours were well capsulated and round to oval in shape. In four out of seven cases, the tumour was located in the tail of pancreas. All the solid enhancing portions showed moderate enhancement of at least 20-30 HU compared to unenhanced scan, on the other hand the cystic parts remained unenhanced with <5 HU variation in comparison to the plain scan. Histopathological examination exhibited characteristic poorly cohesive cuboidal cells arranged in papillaroid pattern having fine nuclear chromatin with nuclear grooves.

Conclusion

Solid pseudopapillary neoplasm is a high diagnostic possibility in case of a young female having pancreatic mass and needs to be evaluated with triphasic contrast enhanced CT scan, followed by FNAC and or histopathological examination.

[Minimally invasive and robot-assisted surgery for pancreatic cystic tumors]

BACKGROUND

The indications for resection of pancreatic cystic lesions (PCL) are often complex and the operative risk has to be balanced against the risk of malignant transformation. The aim of the study was to provide a synopsis of the current treatment results of minimally invasive surgery for PCL.

METHODS

A systematic literature search was performed using the Medline database (PubMed). Subsequently, the retrieved literature was selectively reviewed.

RESULTS

No published prospective randomized controlled trials have yet addressed the comparison of open and minimally invasive surgery of PCL; however, retrospective case studies have demonstrated the feasibility, safety and a comparable morbidity after minimally invasive distal pancreatectomy (DP), pancreatoduodenectomy (PD), central (CP) or total pancreatectomy and enucleation. Whereas most DPs are performed laparoscopically, the experience of minimally invasive PD has been consolidated for the robot-assisted approach but is concentrated in only a few centers. The number of published reports on minimally invasive organ-sparing pancreas procedures (e. g. CP or enucleation) for PCL is scarce; however, the available (selected) results are promising.

CONCLUSION

Minimally invasive surgery for PCL has the potential to reduce the operative trauma to the patients, while at the same time causing comparable or less morbidity. This requires an increasing specialization of complex minimally invasive resections. The clinical use of robotic systems will grow for the latter cases. A prospective registry of the results should be mandatory for quality management.