Efficacy of Reinforced Stapler for Preventing Postoperative Pancreatic Fistula After Minimally Invasive Distal Pancreatectomy.

BACKGROUND/AIM: Although minimally invasive distal pancreatectomy (MIDP) has become a treatment option for benign and malignant pancreatic tumors, the safety and efficacy of reinforced staplers in MIDP remain controversial. The present study was performed to evaluate the safety of reinforced staplers in MIDP and identify the risk factors for postoperative pancreatic fistula (POPF) after MIDP with reinforced staplers. PATIENTS AND METHODS: In total, 92 consecutive patients who underwent MIDP at NHO Kyushu Medical Center from July 2016 to August 2023 were enrolled in this retrospective study. In all patients, a reinforced black cartridge triple-row stapler (Covidien Japan, Tokyo, Japan) was used during MIDP. The primary endpoint was the incidence of clinically relevant POPF. The risk factors for POPF were evaluated using multivariate analysis. RESULTS: Among the 92 patients, 74 underwent laparoscopic distal pancreatectomy and 18 underwent robot-assisted distal pancreatectomy. Clinically relevant POPF occurred in seven (7.6%) of 92 patients. The rate of severe complications (Clavien-Dindo grade ≥III) was 10.8%, and the mortality rate was 0%. The median postoperative hospital stay was 14 days. Multivariate logistic regression analysis showed that the independent risk factor for clinically relevant POPF after MIDP with a reinforced stapler was a body mass index of ≥22.6 kg/m2 (p=0.050, odds ratio=7.60). CONCLUSION: This study confirmed the safety and efficacy of reinforced staplers for preventing POPF after MIDP. A high body mass index was the only risk factor for clinically relevant POPF after MIDP with a reinforced stapler.

Analysis of the effect of staple line reinforcement on leaking and bleeding after sleeve gastrectomy from the UK National Bariatric Surgery Registry.

INTRODUCTION: Sleeve gastrectomy (SG) is currently the most frequently performed procedure for obesity worldwide. Staple line reinforcement (SLR) has been suggested as a strategy to reduce the risk of staple line leak or bleeding; however, its use for SG in the United Kingdom (UK) is unknown. This study examined the effect of SLR on the development of postoperative complications from SG using a large national dataset from the UK. METHODS: Patients undergoing either primary or revision SG over 10 years from Jan 2012 to Dec 2021 were identified by the National Bariatric Surgery Registry. Comparative and logistic regression analyses were undertaken to determine the effect of SLR on staple line leak and bleeding. RESULTS: During this time, 14,231 patients underwent SG for whom there were complete data. Of these, 76.5% were female and the median age was 46 years (IQR: 36-53). The rate of surgical complications was 2.3% (n = 219/14,231). The incidence of bleeding was 1.3% (n = 179/14,231) and leak was 1.0% (n = 140/14,231). Over time, the use of SLR of any variety declined significantly from 99.7% in 2012 to 57.3% in 2021 (p < 0.001). Multivariable (adjusted) regression analysis demonstrated that neither the use of nor the type of reinforcement had any effect on the rate of bleeding or leaking. CONCLUSION: SLR for SG has declined in the UK since 2012. There were no differences in staple line leak or bleed with or without reinforcement.

Stapled vs handsewn anastomosis and anastomotic leaks in gastric cancer surgery-a population-based nationwide study in Finland.

BACKGROUND: There is a lack of evidence regarding anastomotic technique and postoperative complications in gastric cancer surgery. This study aimed to evaluate whether there are differences between stapled and handsewn anastomosis and anastomotic leaks. METHODS: This was a population-based, retrospective, nationwide cohort study in Finland using the Finnish National Esophago-Gastric Cancer Cohort. Patients undergoing gastrectomy with available postoperative complication data were included. Logistic regression analysis was used to calculate the odds ratios with 95% CIs, adjusted for calendar period of surgery, age at surgery, sex, comorbidity, tumor stage, neoadjuvant therapy, minimally invasive surgery, type of gastrectomy, radical resection, and type of anastomosis. RESULTS: Of the 2164 patients, 472 of all patients (21.8%) had handsewn anastomosis and 1692 of all patients (78.2%) had stapled anastomosis. In the unadjusted analysis, anastomotic leaks were significantly lower in the handsewn group (hazard ratio [HR], 0.42; 95% CI, 0.22-0.79) than the stapled group, but after adjustment for known prognostic factors, this association was no longer significant (HR, 0.57; 95% CI, 0.27-1.21). In the analysis stratified by gastrectomy type (distal or total), no differences in anastomotic leaks were observed between anastomotic techniques. CONCLUSION: In this population-based nationwide study, anastomotic technique (stapled or handsewn) was not associated with anastomotic leaks in any, distal or total, gastrectomy.

Parastomal hernia repair according to Modified Stapled Mesh Stoma Reinforcement Technique (mSMART): which are the results ?

INTRODUCTION: Parastomal hernia repair is a real surgical challenge because of the high rate of recurrence. The Stapled Mesh Stoma Reinforcement Technique (SMART) is a keyhole-like technique in which the mesh is stapled to the fascia using a circular mechanical stapler. METHODS: A prospective study from January 2021 to February 2023 was conducted including all patients operated with the SMART technique. Primary endpoint was the recurrence rate during the follow-up. Secondary endpoints were reoperation, Surgical site Occurrence (SSO) and deep (mesh) surgical site infection (SSI) within 30 days postoperatively. RESULTS: Sixteen patients operated on SMART procedures were included. The mean follow-up was 11.3 ± 9.2 months. The SSO rate was 18.7% (n = 3). A seroma was drained radiologically (IIIa), one haematoma was evacuated surgically (IIIb) and one patient presented a postoperative lesion of a ureter after a parastomal Bricker's hernia repair. In addition, there was one death due to multiple organ failure (V). There was no SSI. The recurrence rate was 57.1% during the follow-up. CONCLUSION: This study shows disappointing results for this SMART technique, with a high recurrence rate.

Comparing stapler and sutured mesh fixation techniques for laparoscopic TAPP repair: a study on chronic groin pain on 3-year follow-up.

Trans-abdominal preperitoneal (TAPP) and totally extraperitoneal (TEP) repairs are the available surgeries for inguinal hernias, with both methods of laparoscopic repairs requiring mesh applications. This study analyzes the correlation between sutured versus stapler mesh fixation in a laparoscopic TAPP for unilateral groin hernia regarding chronic pain during 3-year follow-up. A total of 130 patients with laparoscopic hernia undergoing TAPP repair were randomized into 2 groups based on their fixation technique-one with sutures and the other with stapler. Postoperative complications and chronic groin pain were noted for each technique. Equal number of participants was present in the stapler and suture groups, with the majority having an ASA score of one. The mean age was 42.50 ± 13.86 years, and the body mass index (BMI) was 27.47 ± 5.88. The stapler group presented a shorter mean operative time than the suture group. However, the stapler group had a significantly higher mean VAS score than the suture group. Most participants in the suture group (89.2%) had LOS for 1 day, while a 2-day LOS was significantly higher in the stapler group (12.3%) than in the suture group (9.2%). No patient reported mesh erosion, conversion, recurrence, testicular atrophy, and mesh infection. Early postoperative pain was more in stapler group along with long hospital stay, but both were non-significant. Chronic postoperative pain results and recurrence incidences over 3-year follow-up were also similar. Re-admission rates were minimal, no significant complications occurred.

Stapled Anastomosis Versus Hand-Sewn Anastomosis With Mucosectomy for Ileal Pouch-Anal Anastomosis: A Systematic Review and Meta-analysis of Postoperative Outcomes, Functional Outcomes, and Oncological Safety.

PURPOSE: This systematic review and meta-analysis aimed to compare outcomes between stapled ileal pouch-anal anastomosis (IPAA) and hand-sewn IPAA with mucosectomy in cases of ulcerative colitis and familial adenomatous polyposis. METHODS: This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Review and Meta-analysis) guidelines 2020 and AMSTAR 2 (Assessing the methodological quality of systematic reviews) guidelines. We included randomized clinical trials (RCTs) and controlled clinical trials (CCTs). Subgroup analysis was performed according to the indication for surgery. RESULTS: The bibliographic research yielded 31 trials: 3 RCTs, 5 prospective clinical trials, and 24 CCTs including 8872 patients: 4871 patients in the stapled group and 4038 in the hand-sewn group. Regarding postoperative outcomes, the stapled group had a lower rate of anastomotic stricture, small bowel obstruction, and ileal pouch failure. There were no differences between the 2 groups in terms of operative time, anastomotic leak, pelvic sepsis, pouchitis, or hospital stay. For functional outcomes, the stapled group was associated with greater outcomes in terms of seepage per day and by night, pad use, night incontinence, resting pressure, and squeeze pressure. There were no differences in stool Frequency per 24h, stool frequency at night, antidiarrheal medication, sexual impotence, or length of the high-pressure zone. There was no difference between the 2 groups in terms of dysplasia and neoplasia. CONCLUSIONS: Compared to hand-sewn anastomosis, stapled ileoanal anastomosis leads to a large reduction in anastomotic stricture, small bowel obstruction, ileal pouch failure, seepage by day and night, pad use, and night incontinence. This may ensure a higher resting pressure and squeeze pressure in manometry evaluation. PROTOCOL REGISTRATION: The protocol was registered at PROSPERO under CRD 42022379880.

The "double-fired" gastro-jejunostomy as a form of improved efficiency during Whipple procedure.

BACKGROUND: Gastro-jejunostomy (GJ) after pylorus-resecting pancreatoduodenectomy (PD) is most commonly performed in a hand-sewn fashion. Intestinal stapled anastomosis are reported to be as effective as hand-sewn in terms of patency and risk of leakage in other indications. However, the use of a stapled gastro-jejunostomy hasn't been fully assessed in PD. The aim of the present technical report is to evaluate functional outcomes of stapled GJ during PD, its associated effect on operative time and related complications. METHODS: The institutional database for pancreatic duct adenocarcinoma (PDAC) was retrospectically reviewed. Pylorus resecting open PD without vascular or multivisceral resections were considered for the analysis. The incidence of clinically significant delayed gastric emptying (DGE from the International Stufy Group of Pancreatic Surgery (ISGPS) grade B and C), other complications, operative time and overall hospitalization were evaluated. RESULTS: Over a 10-years study period, 1182 PD for adenocarcinoma were performed and recorded in the database. 243 open Whipple procedures with no vascular and with no associated multivisceral resections were available and constituted the study population. Hand-sewn (HS) anastomosis was performed in 175 (72 %), stapled anastomosis (St) in 68 (28 %). No significant differences in baseline characteristics were observed between the two groups, with the exception of a higher rate of neoadjuvant chemotherapy in the HS group (74 % St vs. 86 % HS, p = 0.025). Intraoperatively, a significantly reduced median operative time in the St group was observed (248 min St vs. 370 mins HS, p < 0.001). Post-operatively, rates of clinically relevant delayed gastric emptying (7 % St vs. 14 % HS, p = 0.140), clinically relevant pancreatic fistula (10 % St, 15 % HS, p = 0.300), median length of stay (7 days for each group, p = 0.289), post-pancreatectomy hemorrhage (4.4 % St vs. 6.3 % HS, p = 0.415) and complication rate (22 % St vs. 34 % HS, p = 0.064) were similar between groups. However, readmission rates were significantly lower after St GJ (13.2 % St vs 29.7 % HS, p = 0.008). CONCLUSION: Our results indicate that a stapled GJ anastomosis during a standard Whipple procedure is non-inferior to a hand-sewn GJ, with a comparable rate of DGE and no increase of gastrointestinal related long term complications. Further, a stapled GJ anastomosis might be associated with reduced operative times.

Mechanical properties and tissue damage caused by staples in gastrointestinal anastomosis.

Gastrointestinal surgery using a stapler is usually associated with tissue damage, anastomosis leakage, bleeding, and other complications, which is one of the effective methods for treating digestive tract cancer. The cutting properties of staples and the tissue damage occurring in the process of stapling porcine esophageal and gastric tissues have been evaluated and a new type of stapler has been designed. Since different structural and mechanical properties esophageal and gastric tissues layers, the puncturing force exhibits a fluctuating trend. Compressive stress caused by the bending of the staple legs can lead to the destruction of the vascular network inside the tissue, tissue deforms and tears. Finally, a staple with an internal incision arc (IIA) tip is designed, which meeting the performance requirements.

The effect of fibrin glue in preventing staple-line leak after sleeve gastrectomy. An experimental study in rats

Abstract Purpose To evaluate the effect of fibrin glue on staple-line leak after sleeve gastrectomy. Methods Fourteen adult wistar rats 300 gr were randomized into two groups: Control group (n=7) and study group (n=7). All the rats underwent sleeve gastrectomy using lineer stapler. In the study group, fibrin glue was used to reinforce the staple-line. The rats were sacrificed 7 days after surgery. The stomach was resected, submerged in saline and exposed to excess pressure to obtain a burst pressure value. The gastric staple line was evaluated histopathologically according to the Ehrlich Hunt scale. The results of the two groups were compared. Results The mean Ehrlich-Hunt scores for inflammation, fibroblastic activity and neo-angiogenesis were similar between the groups (p>0.05). Collagen deposition was significantly higher in study group (3.42±0.53) when compared with control group (2.57±0.78) (p=0.035). The mean burst pressure was 137.8±8.5 mmHg for control group and 135.0±8.1 mmHg for study group (p=0.536). Conclusion Reinforcement of the staple-line with fibrin glue has no effect on the burst pressure after sleeve gastrectomy. More studies are needed to evaluate the precautions against leak after sleeve gastrectomy.

Retained or expelled staples after transanal stapled surgery: this is the problem! / Grampos retidos ou expelidos em seguida à cirurgia transanal com grampeador: eis aí o problema!

ABSTRACT Study objective: The aim is to assess the presence and persistence of the agraphes at the level of staple line after transanal stapled surgery. Methods: From April to December 2016 one-hundred-thirteen patients with variable follow-up (6 months-10 years) were randomly selected among all the patients undergone transanal stapled surgery for haemorrhoidal disease or functional disorders such as obstructed defecation syndrome. Only 87 patients agreed to participate this study. All the patients underwent digital exploration, anoscopy and 360° tridimensional transanal ultrasound. Main results: Different types of stapled transanal surgical procedures were performed: 48 transanal rectal resection with high volume device, 24 stapled haemorrhoidopexy, 8 Double Stapled Haemorrhoidopexy, 7 Transtarr. In 41.4% the staple line was not identified with digital examination or anoscopy and 17.2% of patients have some staples partially expelled inside the lumen. 360° tridimensional transanal ultrasound showed a complete staple line at the ano-rectal junction which appears as an interrupted hyperechoic circular layer. Conclusion: The staples after stapled transanal surgery remain at the level of the staple line independently from the device used by the surgeon leading to the necessity of a shared and adequate language, in fact the shed staples need to be considered as expelled instead of retained.

RESUMO Objetivo do estudo: Avaliar a presença e persistência dos agrafes ao nível da linha de aplicação dos grampos, em seguida à cirurgia transanal com grampeador. Métodos: De abril até dezembro de 2016, 113 pacientes com seguimentos variáveis (6 meses-10 anos) foram aleatoriamente selecionados entre todos os pacientes tratados com cirurgia transanal com grampos para tratamento de hemorroidas ou de transtornos funcionais, por exemplo, síndrome de evacuação obstruída. Apenas 87 pacientes concordaram em participar do estudo. Todos os pacientes passaram por exploração digital, anoscopia e ultrassonografia transanal tridimensional de 360°. Resultados principais: Foram realizados diferentes tipos de procedimentos cirúrgicos transanais com grampeador: 48 ressecções retais transanais com uso de grampeador de grande volume, 24 hemorroidopexias com grampeador, 8 hemorroidopexias com grampos duplos e 7 procedimentos com grampeador Transtar. Em 41,4% dos tratamentos, não foi possível identificar a linha de grampeamento com exame digital ou com anoscopia, e em 17,2% dos pacientes alguns grampos foram expelidos para o lúmen. A ultrassonografia transanal tridimensional de 360° revelou uma linha de grampeamento completo na junção anorretal, assumindo o aspecto de uma camada circular hiperecoica interrompida. Conclusão: Em seguida à cirurgia transanal com grampeamento, os grampos permanecem ao nível da linha de grampeamento, independentemente do tipo de grampeador usado pelo cirurgião, o que torna necessária uma linguagem compartilhada e adequada; de fato, os grampos soltos devem ser considerados como expelidos, em lugar de retidos.

Mucosectomía rectal con engrapadora sola y combinada con otros procedimientos quirúrgicos anorrectales: análisis multivariado de los factores que afectan el resultado clínico / Stapled rectal mucosectomy alone and in combination with other surgical anorectal procedures: multivariate analysis of factors affecting clinical outcome

Objetivo: Comparar el resultado clínico de la mucosectomía rectal con engrapadora (MRE) sola y de la MRE combinada con esfinterotomía y con plastia anal de colgajos cutáneos, y examinar qué factores influyen sobre las complicaciones y la satisfacción del paciente. Material y métodos: Se incluyeron pacientes con enfermedad hemorroidal grados II a IV sometidos a MRE sola o en combinación con otros procedimientos. Se analizaron las complicaciones posoperatorias, resolución de síntomas y grado de satisfacción. Resultados: 241 pacientes consecutivos con seguimiento mínimo de un año se dividieron en tres grupos: MRE sola (n = 187), MRE combinada con esfinterotomía (n = 31) y MRE combinada con plastia de colgajos (n = 23). Los pacientes con MRE con esfinterotomía presentaron un porcentaje de complicaciones mayor que el resto (32 versus 12.8 % y 13 %, respectivamente, p = 0.02). La MRE con esfinterotomía se asoció con mayor riesgo de complicaciones que la MRE sola (RM = 3.5, IC 95 % = 1.4-8.7); la inclusión exclusiva de epitelio columnar en la zona resecada se asoció con menor riesgo de complicaciones que cuando se incluyó además epitelio transicional (RM = 0.4, IC 95 % = 0.2-0.8). La resolución de síntomas preoperatorios en la mayor parte de los pacientes fue > 80 % en los tres grupos. No hubo asociación de complicaciones o del tipo de procedimiento con el grado de satisfacción. Cuando el porcentaje de síntomas resueltos fue < 80 % se asoció con grado bajo o intermedio de satisfacción (p < 0.001). Conclusiones: La resolución de los síntomas preoperatorios con los tres procedimientos es similar. La MRE con esfinterotomía tiene mayor riesgo de complicaciones. El grado de satisfacción se asocia con la resolución de los síntomas preoperatorios.

BACKGROUND: We undertook this study to compare the clinical outcome of stapled rectal mucosectomy (SRM) alone and in combination with sphincterotomy and cutaneous flap anoplasty and to determine the influence of factors related to complications and patient satisfaction. METHODS: Patients with second- to fourth-degree hemorrhoids who underwent SRM alone or in combination with other anorectal procedures were included. Postoperative complications, symptom resolution and patient satisfaction were analyzed. RESULTS: Two hundred forty one patients with a minimum follow-up of 1 year were divided into three groups: SRM alone (n = 187), SRM combined with sphincterotomy (n = 31) and SRM combined with cutaneous flap anoplasty (n = 23). Patients with SRM with sphincterotomy showed a higher complication rate than the other groups (32 vs. 12.8% and 13%, respectively, p = 0.02). SRM combined with sphincterotomy was associated with a higher rate of complications (OR = 3.5; 95% CI = 1.4-8.7). SRM alone with low mucosal resection was associated with a lower complications rate (OR = 0.4, 95% CI = 0.2-0.8). Resolution of preoperative symptoms was >80% among the three groups. There was no association between complications and type of procedure with satisfaction level. Resolution of symptoms <80% was associated with low/intermediate level of satisfaction (p <0.001). CONCLUSIONS: Resolution of preoperative symptoms is similar among the three groups. SRM combined with sphincterotomy has a higher risk of complications. The satisfaction level is associated with resolution of preoperative symptoms.

Initial experience with stapled hemorrhoidopexy for treatment of hemorrhoids / Experiência inicial com o tratamento da doença hemorroidária pela técnica de grampeamento circular

BACKGROUND: Introduction of stapled hemorrhoidopexy by Longo in 1998 represented a radical change in the treatment of hemorrhoids. By avoiding multiple excisions and suture lines in the perianal region, stapled hemorrhoidopexy is intended to offer less postoperative pain than with conventional techniques. OBJECTIVE: To report and analyze the intra and postoperative results gained during initial experience with stapled hemorrhoidopexy. METHODS: One hundred and fifty five patients (67 males) with average age of 39.5 years (21-67 years) underwent stapled hemorrhoidopexy between June 2000 and December 2003 with symptomatic third-degree (n = 74) and fourth-degree (n = 81) hemorrhoids. Mean follow-up period was 20 months (14-60 months). RESULTS: Preoperative symptoms were prolapse (96.7 percent) and anal bleeding (96.1 percent). Overall mean operative time was 23 minutes (16-48 minutes). We observed one case of stapler failure and one case of failure to introduce the stapler occurred in a patient with previous anal surgery. Additional sutures for hemostasis were required in 103 patients (66.5 percent). Resection of skin tags was performed in 45 cases (29 percent). Postoperatively scheduled analgesia with oral dipyrone and celecoxib was enough for pain control in 131 patients (84.5 percent). Rescue analgesia was necessary in 24 cases (15.5 percent). Five patients needed opiates for pain control. Hospital discharge took place on the first postoperative day in 140 patients (90.3 percent). First defecation without pain was reported by 118 patients (76.1 percent). Postoperative complications were anal bleeding (10.3 percent), severe pain (3.2 percent), urinary retention (3.9 percent), fever without any signs of perianal infection (1.9 percent), incontinence for flatus (1.9 percent), hemorrhoidal thrombosis (1.3 percent). Two patients presented symptoms of recurrent hemorrhoidal disease and were successfully treated by conventional hemorrhoidectomy. They were no cases of...

RACIONAL: A introdução por Longo em 1998, da hemorroidopexia pela técnica de grampeamento circular representou uma mudança radical no tratamento cirúrgico da doença hemorroidária, ao passo que propõe o reposicionamento da mucosa anorretal prolapsada, sem excisão do mamilo hemorroidário, cursando assim com menor dor e menor tempo de recuperação pós-operatórios. OBJETIVO: Apresentar e analisar os resultados intra e pós-operatórios obtidos durante a experiência inicial com a técnica de grampeamento circular. PACIENTES E MÉTODO: Foram incluídos 155 pacientes (67 homens) com média de idade de 39,5 anos (21-67 anos) e doença hemorroidária sintomática grau III (n = 74) e IV (n = 81), operados consecutivamente pelo método do grampeamento circular entre junho de 2000 e dezembro de 2003. Resultados e complicações pós-operatórias foram aferidos num tempo de seguimento médio de 20 meses (14-60 meses). RESULTADOS: Os principais sintomas pré-operatórios foram prolapso (96,7 por cento) e sangramento (96,1 por cento). O tempo operatório médio foi de 23 minutos (16-48 minutos). Houve um caso de falha do equipamento e um de impossibilidade de introdução do mesmo (paciente com cirurgia anal prévia). Hemostasia adicional com sutura foi necessária em 103 pacientes (66,5 por cento) e a ressecção de plicomas foi realizada concomitantemente ao procedimento em 45 pacientes (29 por cento). A analgesia pós-operatória via oral com dipirona e celecoxib foi eficiente no controle da dor em 131 pacientes (84,5 por cento), 24 (15,5 por cento) necessitaram de analgesia complementar, sendo que 5 pacientes receberam opióides devido a dor intensa. A maioria dos pacientes (140 - 90,3 por cento) teve alta no primeiro dia de pós-operatório e 118 (76,1 por cento) referiram a primeira evacuação sem dor. As complicações pós-operatórias observadas foram: sangramento (10,3 por cento), tenesmo (3,9 por cento), retenção urinária (3,9 por cento), febre sem sinais infecciosos (1,9 por cento), incontinência...

Stapled hemorrhoidectomy: present status

OBJETIVO: Avaliar se a eficácia da técnica de hemoirrodectomia por grampeamento é maior do que a tradicional, assim como analisar a relação custo-benefício antes de seu emprego rotineiro. FONTES DE DADOS: Analisaram-se retrospectivamente, várias publicações mundiais de ensaios randomizados, no período de 2000 a 2004, em que se compararam a intensidade da dor, o tempo de retorno às atividades profissionais, a importância de incontinência fecal e outras complicações no período pós-operatório de grupos de pacientes submetidos a ambas as técnicas, durante diferentes períodos de seguimento clínico. CONCLUSÕES: A técnica de hemoirrodectomia por grampeamento propicia menor intensidade de dor e retorno mais precoce às atividades profissionais, quando comparada à hemoirrodectomia convencional. Entretanto, sua eficácia não foi determinada, uma vez que ainda não estão disponíveis estudos prospectivos e randomizados com grandes casuísticas e seguimentos a longo prazo.