Mechanisms of hemostatic failure during laparoscopic nephrectomy: review of Food and Drug Administration database

Assessing the Reproducibility of Research Based on the Food and Drug Administration Manufacturer and User Facility Device Experience Data

OBJECTIVE

This article aims to assess the reproducibility of Manufacturer and User Facility Device Experience (MAUDE) data-driven studies by analyzing the data queries used in their research processes.

METHODS

Studies using MAUDE data were sourced from PubMed by searching for "MAUDE" or "Manufacturer and User Facility Device Experience" in titles or abstracts. We manually chose articles with executable queries. The reproducibility of each query was assessed by replicating it in the MAUDE Application Programming Interface. The reproducibility of a query is determined by a reproducibility coefficient that ranges from 0.95 to 1.05. This coefficient is calculated by comparing the number of medical device reports (MDRs) returned by the reproduced queries to the number of reported MDRs in the original studies. We also computed the reproducibility ratio, which is the fraction of reproducible queries in subgroups divided by the query complexity, the device category, and the presence of a data processing flow.

RESULTS

As of August 8, 2022, we identified 523 articles from which 336 contained queries, and 60 of these were executable. Among these, 14 queries were reproducible. Queries using a single field like product code, product class, or brand name showed higher reproducibility (50%, 33.3%, 31.3%) compared with other fields (8.3%, P = 0.037). Single-category device queries exhibited a higher reproducibility ratio than multicategory ones, but without statistical significance (27.1% versus 8.3%, P = 0.321). Studies including a data processing flow had a higher reproducibility ratio than those without, although this difference was not statistically significant (42.9% versus 17.4%, P = 0.107).

CONCLUSIONS

Our findings indicate that the reproducibility of queries in MAUDE data-driven studies is limited. Enhancing this requires the development of more effective MAUDE data query strategies and improved application programming interfaces.

Total clipless laparoscopic nephrectomy carried out with the LigaSure device: Preliminary experience

BACKGROUND

Total laparoscopic nephrectomy has become the standard method for the removal of diseased kidneys.

OBJECTIVES

The purpose of this study was to evaluate the feasibility of the LigaSure vessel closure system during laparoscopic nephrectomy.

METHODS

From January 2018 to June 2018, the LigaSure device was used in 5 patients undergoing laparoscopic nephrectomy for non functional kidney. Nephrectomy was carried out without the use of clips or sutures for vessel closure. We report intraoperative findings, conversion rates, blood loss, operative time, morbidity, and postoperative outcomes.

RESULTS

Median operative time was 45minutes (range 25 to 60min). Median blood loss was 30mL (range 10 to 50mL). No conversions to open surgery were necessary. No patients experienced major bleeding intraoperatively or postoperatively. All patients left the hospital one day after the procedure. Histopathological examination of the removed kidneys was in favor of chronic non specific pyelonephritis.

CONCLUSIONS

For the treatment of the renal pedicle during total laparoscopic nephrectomy of a destroyed kidney, the LigaSure device appears to be feasible and effective. Our experience is the first to demonstrate the advantages of LigaSure® in laparoscopic nephrectomy: reduction in operating time, blood loss, transfusions and length of stay in hospital.

Mortality related to the use of stapler devices and clip appliers: Analysis of the Food and Drug Administration Manufacturer and User Facility Device Experience database

BACKGROUND

Surgical staplers and clip appliers are commonly used and have a potential to malfunction, which may result in serious injury or death. These events are self-reported to the Food and Drug Administration and compiled in the Food and Drug Administration's Manufacturer and User Facility Device Experience database. This study characterizes mortality related to surgical stapler and clip applier failure reported in the Food and Drug Administration's Manufacturer and User Facility Device Experience database.

METHODS

The Food and Drug Administration's Manufacturer and User Facility Device Experience database was reviewed between 1992 and 2016 for medical device reports related to surgical staplers and clip appliers filed under the following product codes: GAG, FZP, GDO, GDW, KOG, and GCJ. Adverse events including death and the type of device failure were reviewed. Temporal trends in reported deaths related to device failure were analyzed and the Healthcare Cost and Utilization Project database was used to adjust for annual surgical case volume using linear regression analysis.

RESULTS

A total of 75,415 malfunctions, 21,115 injuries, and 676 deaths were associated with the use of surgical stapler and clip applier devices. Most deaths occurred postoperatively (N = 516, 76.3%) and were due to infection/sepsis (N = 89, 17.2%) or vascular injuries (N = 110, 21.3%). Intraoperative mortality (N = 79, 11.7%) was primarily due to vascular injuries (N = 73, 92.4%). Device failures resulting in death were noted both intraoperatively (N = 268, 39.6%) and postoperatively (N = 325, 48.1%). In post hoc root cause analysis, a surgical stapler and clip applier device problem was the most common attributed cause of death (N = 238, 65.4%). In the linear regression analysis, there was a significant increase in the mortality from device failure in the study period after adjusting for annual surgical volume (P < .01).

CONCLUSION

Mortality related to the use of surgical staplers and clip appliers is increasing. Most deaths occurred postoperatively, and an increased awareness of potential life-threatening complications is warranted when these devices are used.

Retrospective Comparison of Clinical and Economic Outcomes of Non-Donor Patients Undergoing Radical Nephrectomy Using One of Two Different Linear Stapler Technologies for Transection of the Renal Vessels: Fixed-Height Gripping Surface Reloads vs Variable-Height Reloads

Purpose

To compare outcomes of non-donor patients undergoing radical nephrectomy using fixed-height gripping surface (FHGS) vs variable-height Tri-Staple™ (VHTS) reloads for transection of the renal vessels.

Patients and Methods

Using the Premier Healthcare Database of US hospital discharge records, we selected non-donor patients undergoing inpatient radical nephrectomy with dates of admission between 1 October 2015, and 31 December 2020 (first=index admission). The primary outcome was in-hospital hemostasis-related complications (hemorrhage, acute posthemorrhagic anemia, and/or procedure to control bleeding) during the index admission. Secondary outcomes included index admission intraoperative injury, blood transfusion, conversion from minimally invasive to open surgery, total hospital costs, length of stay (LOS), discharge status, and mortality as well as 30-day all-cause inpatient readmission. We used stable balancing weights to balance the FHGS and VHTS groups on numerous patient, procedure, and hospital/provider characteristics, allowing a maximum post-weighting standardized mean difference ≤0.01 for all covariates; we also exactly matched the groups on laterality (right vs left kidney) and intended surgical approach (open, laparoscopic, robotic). We used bivariate multilevel mixed-effects generalized linear models accounting for hospital-level clustering to compare the study outcomes between the FHGS and VHTS groups.

Results

After weighting, the FHGS and VHTS groups comprised 2952 and 795 patients, respectively. The observed incidence proportion of the primary outcome of hemostasis-related complications during the index admission was similar between the groups (8.6% for FHGS vs 9.0% for VHTS, difference 0.4% [95% CI −3.2% to 2.5%], P=0.808). Differences between the FHGS and VHTS groups were not statistically significant for any of the secondary outcomes.

Conclusion

Endoscopic surgical staplers have become common for transection of the renal vessels during radical nephrectomy, with FHGS and VHTS being the predominant reload types. In this retrospective study of 3747 non-donor patients undergoing radical nephrectomy, use of FHGS vs VHTS reloads was associated with similar clinical and economic outcomes.

Robotic stapler use: Is it safe?-FDA database analysis across multiple surgical specialties

Introduction

Robotic-assisted techniques are common across many surgical subspecialties. While robotic stapling offers increased surgeon control, there is limited information on surgical complications related to robotic stapler use.

Methods

We reviewed the FDA’s MAUDE database for adverse events related to robotic stapler use.

Results

Upon review of the FDA database, the most frequently reported robotic stapler complications were malfunction, failure to form staple line, device fragmentation, and misfire. 31 Clavien-Dindo grade II or higher complications were attributed to stapler use since 2014.

Conclusions

Further research on prevalence of robotic stapler use is needed to quantity the associated complication rate.

Endovascular Stapler Complications During Minimally Invasive Nephrectomy: An Updated Review of the FDA MAUDE Database From 2009-2019

OBJECTIVE

To characterize the rates of endovascular stapler complications during hilar ligation in minimally invasive radical nephrectomy over the last 10 years.

MATERIAL AND METHODS

We reviewed the Food and Drug Administration Manufacturer and User Facility Device Experience database from January 1, 2009 to August 1, 2019. Staplers were categorized according to type, namely Ethicon Inc. endocutters (Johnson & Johnson, New Brunswick NJ); Endo-GIA (Medtronic, Minneapolis MN); and Endo-TA (Medtronic, Minneapolis MN).

RESULTS

There were 383 cases of complications involving staplers, 63% with Ethicon endocutters; 28% with GIA; and 9% with TA. 22 deaths (5.7% of total complications) were attributed to staplers. No deaths or reoperations occurred due to TA staplers. TA staplers were also associated with a reduced incidence of conversion to open as compared to Ethicon and GIA staplers. Apart from one device, manufacturer evaluation of returned devices either showed no abnormalities or attributed fault to improper use of staplers.

DISCUSSION

We characterized stapler complications during a 10-year period for minimally invasive radical nephrectomy. No deaths or reoperations occurred due to TA staplers, perhaps due to cutting and stapling occurring in separate steps. Based on manufacturer evaluation attributing stapling malfunctions to human errors, training of operating room staff on proper use of these devices is critical to prevent potentially significant complications from occurring.

A systematic review of the quality of cardiovascular surgery studies that extracted data from the MAUDE database

OBJECTIVE

To investigate opportunities and limitations of using the Manufacturer and User Facility Device Experience (MAUDE) database for cardiovascular surgery research, we analyzed the quality of studies having ever used MAUDE, in the field of cardiovascular surgery.

METHODS

We systematically searched the Cochrane Library, PubMed, EMBASE, and Google Scholar for randomized and nonrandomized studies, from inception to July 2019. Two authors evaluated the quality of the retrieved observational studies, according to the National Institutes of Health quality assessment tool for either case series or cross-sectional studies. These tools quantify the quality of case series and cohorts/cross-sectional studies, respectively, with nine and 14 queries.

RESULTS

Fifty-eight studies were included in the final qualitative review. Of 58 identified studies, 32 were case series, 8 were abstracts of case series, and 13 were reviews or case discussion with an included series from MAUDE. Also, five articles were cross-sectional studies. Of the 32 formal case series, 26 (81%) were found to have poor quality. The most common reasons for a poor quality designation included a lack of consecutive participants, undetermined comparability of participants, and undetermined follow-up adequacy. Only one out of five cross-sectional studies had fair quality; four others were evaluated as poor quality studies.

CONCLUSIONS

Cardiovascular surgery studies using the MAUDE database, whether case series or cross-sectional design, are mostly of poor quality. Their low quality is partly caused by poor study design, but mainly by intrinsic limitations to the MAUDE database: cases recruited are not consecutive; patient characteristics are not detailed enough to allow a meaningful comparison of patient characteristics between different patient entries; outcome measures are unclear; there is a limited follow-up; and time-to-event data are lacking. We conclude that the quality of cardiovascular surgery publications that rely on data from MAUDE could be improved if investigators were to extract all relevant data points from MAUDE entries, then apply standard quality assessment tools in compiling and reporting the data. MAUDE might be improved if it used medical case report standards during the process of reporting and indexing adverse events. To calculate the incidence rate of any adverse event, all event-free cases, as well as all adverse events in patients using a device, are required. Neither of these two variables is available in the MAUDE at the time of writing.

Litigation Patterns in Oncologic Nephrectomies: A 30-Year Review

Introduction: The litigious environment encompassing the medical-legal domain is an increasing concern for surgical fields, with urology being no exception. The objective of our study was to systematically review, evaluate, and summarize the factors associated with oncologic nephrectomy litigation to determine possible factors contributing to verdicts or settlements. Materials and Methods: Publicly available verdict reports were retrieved using the Westlaw^® legal database (Reuters). Cases were identified using the search term "nephrectomy" with dates ranging from January 1, 1990 to July 1, 2019. Each case was evaluated by two independent reviewers for defendant specialty, alleged breach in treatment, resulting complications, verdict outcomes, and indemnity payment. Complications were determined to be preoperative, perioperative, and postoperative. Data were analyzed using SPSS software to produce the descriptive statistics. Results: After accounting for duplicates and irrelevant cases, a total of 103 cases were analyzed with more than three-fourths being radical nephrectomies (78%). The most common claim was preoperative negligence (48%); however, negligence in perioperative care received the highest average monetary payment of $5,493,151. Forty-one percent of cases were perioperative with the majority being attributed to vascular injury (46%). The type of perioperative negligence claims and its average payment were found to be statistically significant (p = 0.042). Overall, 57% of cases denied the plaintiff's claims, whereas 28% were awarded. Conclusions: Our data show that although the highest number of cases were caused by preoperative negligence, perioperative negligence accounts for the highest settlement awards. This review provides insights into stages of management in the surgical management of renal cell cancer patients that may be subject to litigation.

Inclusion of a Clip Inside the Cartridge and Failure of the Stapler When Performing a Laparoscopic Sleeve Gastrectomy

The growth of the surgical industry and the development of surgical techniques have allowed us to achieve better results for patients. Laparoscopic staplers are a crucial tool in laparoscopic surgery, and despite their proven safety and efficiency, they have been associated with technical and mechanical failures on rare occasions. Adequate knowledge of the surgical instruments is critical to accomplishing optimal results and to adequately treating these rare malfunctions and their consequences. We present a case of a surgical stapler malfunction due to a titanium clip during laparoscopic sleeve gastrectomy. This mechanical failure produced a complication that was adequately resolved, and the patient completely recovered. Our brief communication shows that errors during sleeve gastrectomy can occur, and that precise surgical skills along with a close follow-up are crucial to improve the patient outcome when these rare complications arise.

Literature Review on the Incidence of Primary Stapler Malfunction

Background. Surgical stapling devices are known for their reliability and convenience. A letter to health care professionals published by the US Food and Drug Administration in March 2019 highlighted the increasing number of adverse events associated with surgical staplers. Driven by a case of stapler malfunction during an elective laparoscopic sleeve gastrectomy, we performed a literature review to investigate the incidence of primary stapler malfunction. We also discuss the common types and an approach to its management. Methods. PubMed, MEDLINE, and EMBASE databases were searched for articles discussing surgical stapler malfunction. Twelve studies were selected that described the incidence and/or consequences of primary stapler malfunction. A narrative synthesis was performed. Results. From observational studies, the incidence ranged from 0.022% to 2.3%. A prospective survey reported that 86% of laparoscopic surgeons either had personal experience with or knew of surgeons who experienced stapler malfunction, implying a higher incidence. Underreporting has been an issue as manufacturers can get exemptions from public reporting. Significantly, higher malfunctions have been reported after exemptions were lifted. The most common types of stapler malfunction are stapler misfire and stapler locking. Major morbidity and mortality have been reported. Conclusion. Surgeons are increasingly reliant on technological innovations. Stapling failure occurs and it is imperative to be aware of this. Given the high volume of stapler use, a high percentage of surgeons are likely to encounter this problem in their career. It is important to have an approach to the prevention and management of this potentially catastrophic complication.

[Comparison of efficacy and safety between two different methods of nephroureterectomy in two centers]

OBJECTIVE

To compare the efficacy and safety of complete transperitoneal laparoscopic nephroureterectomy (CTNU) and traditional retroperitoneoscopic nehroureterectomy (TRNU) for the management of upper urinary tract urothelial carcinoma(UTUC).

METHODS

We retrospectively collected the clinical data of UTUC patients who underwent CTNU or TRNU surgery from January 2011 to December 2018 in Peking University First Hospital and Fujian Provincial Hospital, and compared the clinical characteristics, perioperative parameters, and follow-up results between the CTNU and TRNU surgeries.

RESULTS

Finally, a total of 266 cases were included, with 94 cases in the CTNU group and 172 cases in the TRNU group. The proportion of left side lesions was bigger in TRNU group when compared with CTNU group (P<0.05). No significant differences were observed in clinical characteristics, such as age, gender, body mass index (BMI), American society of anesthesiologists score (ASA score) and tumor laterality. All surgery procedures were completed. The vascular resparing was performed by reason that left arteria renalis was injured accidently during surgical operation in one case of TRNU group. No serious complications were observed in both CTNU and TRNU groups. In CTNU group, operating time was (202.9±76.7) min, estimated blood loss was (68.4±73.3) mL, drainage duration was (3.9±1.5) d, drainage volume was (181.7±251.5) mL, and postoperative hospital stay was (7.8±4.1) d. In TRNU group, operating time was (203.5±68.7) min, estimated blood loss was (130.2±252.1) mL, drainage duration was (4.3 ±1.6) d, drainage volume was (179.1±167.5) mL, and postoperative hospital stay was (8.2±3.7) d. The estimated blood loss in CTNU group was significantly less than that in TRNU group (P=0.005).The median follow-up time was 39 months (range: 1-88 months). The 5-year overall survival rate (OS), cancer specific survival rate (CSS), intra-vesical recurrence free survival rate (IvRFS), disease free survival rate (DFS) of CTNU group was 75.6%, 86.9%, 73.8%, 57.5%, respectively. The OS, CSS, IvRFS and DFS of TRNU group was 66.3%, 83.5%, 75.9%, 58.6%, respectively.No significant differences were observed in the OS, CSS, IvRFS and DFS between the CTNU and TRNU groups.

CONCLUSION

CTNU technique is a safe and effective surgical option, and further prospective randomized controlled trial is needed for further evaluation.

Intraoperative laparoscopic complications for urological cancer procedures

AIM: To structure the rate of intraoperative complications that requires an intraoperative or perioperative resolution.

METHODS: We perform a literature review of Medline database. The research was focused on intraoperative laparoscopic procedures inside the field of urological oncology. General rate of perioperative complications in laparoscopic urologic surgery is described to be around 12.4%. Most of the manuscripts published do not make differences between pure intraoperative, intraoperative with postoperative consequences and postoperative complications.

RESULTS: We expose a narrative statement of complications, possible solutions and possible preventions for most frequent retroperitoneal and pelvic laparoscopic surgery. We expose the results with the following order: retroperitoneal laparoscopic surgery (radical nephrectomy, partial nephrectomy, nephroureterectomy and adrenalectomy) and pelvic laparoscopic surgery (radical prostatectomy and radical cystectomy).

CONCLUSION: Intraoperative complications vary from different series. More scheduled reports should be done in order to better understand the real rates of complications.

Laparoscopic pretransplant nephrectomy with morcellation in autosomic-dominant polycystic kidney disease patients with end-stage renal disease

BACKGROUND

Laparoscopic nephrectomy (LN) in end-stage autosomic-dominant polycystic kidney disease (ADPKD) requires a large abdominal incision for the specimen extraction.

OBJECTIVE

The objective of this study was to describe our technique of LN for end-stage ADPKD followed by morcellation (LNM) of the specimen and extraction through a minimal abdominal incision.

METHODS

The medical records of 19 consecutive patients who underwent pretransplant LNM between 2008 and 2011 by a single experienced laparoscopic surgeon were analyzed. Morcellation was performed with the Gynecare Morcellex™ Tissue morcellator, Ethicon.

RESULTS AND LIMITATIONS

All cases but one were completed laparoscopically. Mean specimen weight was 1,026.8 g. Mean duration of the procedure, estimated blood loss, and hospital stay were 131.3 min, 52.1 ml, and 7.9 days, respectively. Specimens were extracted through a 12-mm trocar in 10/18 patients and through a 3-cm incision in 9/18 cases. Postoperatively, three complications were observed (Clavien grades II, I, and II). The only case of incisional hernia was observed in the converted procedure. Major limitation of the study is its retrospective design.

CONCLUSIONS

In our preliminary series and in the hands of a very experienced laparoscopist, LNM for ADPKD appears as a modern, mini-invasive, and safe technique. Specimen's extraction through a small abdominal incision reduces postoperative pain and incisional hernias and guarantees the final cosmetic result of laparoscopy. The reduced overall morbidity could reduce the period between nephrectomy and transplantation.

[Nephrectomy: complication management]

BACKGROUND

Nephrectomy is a standard procedure that is associated with a low complication rate.

OBJECTIVES

Based on an analysis of the literature, expert recommendations, and our own experience, the management of complications during and after nephrectomy is described.

RESULTS

Complications during and after nephrectomy can be avoided by careful surgical planning, optimal approach and exposure, and precise knowledge of the principles of anatomy. The treatment of bleeding complications and injuries to neighboring structures are essential elements in the management of complications. Hernia and relaxation of the lumbar muscles should be avoided.

CONCLUSION

Morbidity associated with nephrectomy can be reduced by careful surgical planning and paying attention to the basic anatomical and surgical principles.

Robotic suture of a large caval injury caused by endo-GIA stapler malfunction during laparoscopic wedge resection of liver segments VII and VIII en-bloc with the right hepatic vein

Primary endo-GIA stapler malfunction occurred during robotic wedge resection of liver segments VII and VIII en-bloc with the right hepatic vein, in an obese woman diagnosed with single liver metastasis from a previous carcinoid tumour. Haemorrhage was soon controlled by clamping the vena cava below the injury using two wristed forceps angled at 90 degrees . With the two instruments locked in the holding position the ensuing operative strategy was discussed between surgeon and anaesthesia teams. Using the third robotic arm the caval injury was repaired laparoscopically with interrupted polypropylene sutures. The patient was transfused with two units of packed red blood cells, recovered uneventfully, and was discharged on post-operative day five. We conclude that even the most advanced technologies can fail and that surgeons should be fully aware of the consequences of these malfunctions and be prepared for repair. From this point of view, the da Vinci surgical system seems to have some advantages over classical laparoscopic methods including the ability to lock the wristed instruments in the holding position, the use of three arms by the same operating surgeon, and the extreme facilitation of intracorporeal suturing and knot-tying in deep and narrow spaces, extremely difficult if not impossible with conventional laparoscopic instruments.

Use of Hem-o-lok Clips for Vascular Control During Retroperitoneoscopic Nephrectomy in Children

Aim: To evaluate safety and efficacy of 5-mm Hem-o-lok clips in children undergoing retroperitoneoscopic nephrectomy. Material and Methods: Twenty-four retroperitoneoscopic nephrectomies were performed between September 2004 and August 2007. The indications of nephrectomy were ureteropelvic junction obstruction, reflux nephropathy, ectopic ureteral opening with renal dysplasia, and stone disease with pyonephrosis and primary obstructed megaureter with renal dysplasia. Nine cases were on right side and others on left side. Multiple 5- or 10-mm Hem-o-lok clips were used to control renal artery and vein separately in each case. The specimen was mobilized and removed either by extension of a port site incision or by a separate incision at ipsilateral iliac fossa at the lateral border of the rectus muscle. Results: Hem-o-lok clips were deployed on renal pedicle separately in each case. Two clips were deployed on the body side and one on the specimen side. On the left side lumbar, gonadal and adrenal tributaries were also clipped by 5-mm Hem-o-lok clips. No clip dislodgement was observed in any patient. Mean operative time was 111 (80 ± 47) minutes, and mean blood loss was 25 (10 ± 45) mL. Mean hospital stay was 2.4 (1.9-3.1) days. Conclusion: Five- and 10-mm Hem-o-lok clips are safe and effective for renal pedicle control during retroperitoneoscopic nephrectomy in children.

Complications of laparoscopic surgery for renal masses: prevention, management, and comparison with the open experience

CONTEXT

The initial excitement about the laparoscopic treatment of renal masses has been tempered by concerns related to increased operative time, technical complexity, and the suitability of laparoscopic approaches to oncologic surgery.

OBJECTIVE

To provide a comprehensive review of intraoperative and postoperative complications and their prevention and management during laparoscopic surgery of renal tumors.

EVIDENCE ACQUISITION

A literature review of the Medline and Google Scholar databases was performed, searching for renal cell carcinoma, renal mass, laparoscopy, laparoscopic radical nephrectomy, open radical nephrectomy, laparoscopic partial nephrectomy, open partial nephrectomy, laparoscopic cryoablation, laparoscopic radiofrequency ablation, complications, intra-operative, and post-operative. English-language articles published between 1990 and 2008 were reviewed.

EVIDENCE SYNTHESIS

Laparoscopic radical nephrectomy (LRN), whether transperitoneal or retroperitoneal, can be performed safely. The overall complication rate is low and does not significantly differ from that of the open experience. Laparoscopic partial nephrectomy (LPN), in contrast, is a technically challenging procedure. Although the intermediate oncologic outcomes are comparable to those of the open experience, there are concerns related to warm ischemia time, and there is a risk of major complications such as urinary leakage and hemorrhage requiring transfusion. Laparoscopic-assisted ablative therapies (cryotherapy and radiofrequency) are being performed more commonly for the treatment of small exophytic renal lesions with a low complication rate and intermediate oncologic outcomes similar to LRN and LPN.

CONCLUSIONS

Complications associated with the laparoscopic management of renal masses vary among the different procedures and with surgeon experience. The rate of complication appears to be similar to that of open surgery.