Bowel Anastomoses For MIS Procedures 2012 MISS Meeting, Salt Lake City Bowel Anastomoses For MIS Procedures Richard L. Whelan, MD St. Luke’s Roosevelt Hospital New York, N.Y.

Whelan Disclosures Ethicon Endosurgery Olympus Corporation Atrium Corporation Convatec Hooters Restaurants Coca Cola Corporation Frito Lay Hospital Vending Machine Corporate Council (who support lengthy operations)

What does “MIS” Mean? Laparoscopic (no extraction incision) ? Laparoscopic-assisted (extraction incision) ? Hand-assisted ? Hybrid (part laparoscopic, part open) ? SILS ? Robotic ? NOTES ?

Number of Splinter MIS Methods is Growing Each new method has a group of devoted proponents who have mastered the method In their hands it works well Each splinter method handles certain aspects of colorectal resection differently It is now harder to give a general talk on some topics because what is said will not apply to all MIS methods

This Talks Comments Apply to the Following Methods: Laparoscopic (no extraction incision) Laparoscopic-assisted (extraction incision) Hand-assisted

What Are You Comfortable Doing? In the end, the surgeon must be comfortable with the method selected If you want to learn a new method then: Read about it, watch videos, talk/visit with surgeons who use the method Consider doing the first few cases with someone in your area who has experience What you hear at this conference must be considered in the context of your skill set and your MIS experience

Types of Bowel Anastomoses Stomach to small bowel Small bowel to small bowel Small bowel to colon Colon to colon Colon to rectum Colon to anus

Types of Anastomoses End to End Side to Side End to Side Isoperistaltic vs Anti-peristaltic End to Side Pouch formation + anastomosis Ileal colonic

Means of Rejoining the Bowel Staplers Circular EEA, linear GIA stapler, TA-staplers Hand-sewn Combination Stapled off bowel end & hand sewn side to side anastomosis Stapled anastomosis reinforced with sutures Pressure (seldom used) Murphy button Niti method

Colorectal Anastomoses After Laparoscopic Bowel Resection Bariatric / Upper GI and MIS General surgeons: Staplers Hand-sewn methods Colorectal surgeons Rely on staplers predominately In general, few intracorporeal hand-sewn ‘moses. Need to be comfortable sewing intracoporeally

Sigmoid & Low Anterior Resection Almost all distal L anastomoses done in the same manner (double stapled circular EEA): Specimen exteriorized via lower abdominal extraction incision Extracorporeal pursestring and anvil placement Intracorporeal docking of anvil and firing of stapler

Laparoscopic-Assisted Sigmoid & Low Anterior Resection

Hand-assisted LAR

Exteriorization of Specimen

Placement of Anvil in Proximal Bowel

EEA Anastomosis

Stapled EEA Anastomosis

Leak Test After EEA Anastomosis Alerts surgeon as to presence of leak Choices: Rigid procto with anastomosis submerged Flexible sig + mosis submerged (CO2 for insufflation of bowel) Bulb syringe injected air/betadine in rectum If leak found suture reinforcement of anastomosis then retest ? Need for proximal stoma if leak found or doughnuts incomplete (must check doughnuts)

Circular EEA Anastomosis Proper stapler size If too big, anvil won’t fit If too small, then the “doughnut” may be too bulky Must clear mesentery Is anus strictured or narrowed? Must consider colon & rectal diameters Largest size possible

Factors That Impact Distal Left Anastomotic Healing Level of the anastomosis (how low?) Blood supply Unusual anatomy (vessel origin, marginal art.) Division IMA at origin or more distal Tension  flexure takedown Abnormal tissue Neoadjuvant RT/chemo Inflammatory bowel disease Critical co-morbidities (cardiac, vascular)

How to Avoid Leaks For Sigmoid/LAR Anastomoses Splenic flexure takedown in great majority Carefully assess & understand the arterial anatomy Carefully assess vascularity of proximal end when placing dougnut Use sizers to make sure that stapler can be inserted to proximal end of Hartmann’s pouch

Sigmoid Resection for Diverticulitis Preserve IMA (which improves blood supply) Devascularize specimen in mid- mesentery Preserves pelvic autonomic nerves Danger here is leaving distal rectosigmoid colon and subsequent difficult stapler insertion (to reach proximal end of Hartmann’s) Can partially mobilize in presacral plane (without detaching or dividing all attachments in order to preserve nerve supply)

Fully Laparoscopic Anastomosis Transanal extraction of specimen Transanal introduction of EEA Anvil Placement of anvil in proximal bowel Anvil into bowel end and then endoloop Anvil spike exits side of proximal bowel and stapler used to close the bowel end Close open end of Hartmann’s pouch Insert stapler transanally Docking of anvil and firing of stapler

Coloanal Anastomosis Mucosectomy (Lone star retractor) After TME to levators (breakthrough tricky) TATA (done at start of case) Need fully mobilized proximal colon Flexure takedown IMA at aorta and IMV proximal to L colic Handsewn colon to anoderm anastomosis +/- colonic J Pouch Has clear functional implications

Ileocolic and Colo-colic Anastomoses Intracorporeal vs. Extracorporeal Majority done extracorporeally Can be safely done intracorporeally Latter is harder to accomplish, may add time to operation Is extraction incision size appreciably smaller for intracorporeal method? For most probably not. Does it matter ? Not been well studied. There is little comparative data.

Ileal to Transverse Colon Anastomosis: The Problem The length of the Middle Colic Artery is highly variable In some patients it is very short and will not easily reach outside via small extraction incision In obese patients with a thick abdominal wall this can be a big problem Intracorporeal anastomosis makes most sense in the very obese population

Right Hemicolectomy: Standard Periumbilical Extraction Incision Takeoff of Middle colic vessels Extraction Incision

Right Hemicolectomy: Extraction Incision in Obese & Short Mesentery Patients Takeoff of Middle colic vessels

Right Hemicolectomy Epigastric Extraction Site Takeoff of Middle colic vessels

Extracorporeal Anastomosis Two side to side stapling methods Remove specimen first, then anastomose Disadvantage: 3 crossing staple lines usually Make anastomosis with bowel still in continuity (Barcelona Method) Advantage: avoid 3 staple lines & fewer cartridges Disadvantage: less sound oncologically ? GIA 75 (or 80 mm) stapler used for both

Extracorporeal Ileocolic Anastomosis

Intracorporeal Anastomoses

Summary Numerous ways to skin a cat Before using new method fully investigate & learn about the technique (video/talk/observation). Mentor, if possible. There are nuances to each method Must be comfortable with method chosen Good assistant and considerable colon experience prior to LAR / TME Divert proximally if concerned about distal L anastomosis

Conditions Necessary for Anastomotic Healing Adequate blood supply Lack of tension Technically “sound” anastomosis Healthy, non-diseased bowel ends

Risk Factors for Anastomotic Leaks Level of the anastomosis (< 6 cm) ** ++ Neoadjuvant RT / chemo ** Perioperative cardiac event * Other co-morbidities (lung, liver, DM)+ Male gender ? Smoking, excessive ETOH ? Double stapled method (vs handsewn) ^ ^^ *Lyall et al. Colorectal Dis 2003;9:801-7. **Heald RJ et al. Dis Col Rectum 1981;24:437-44. +Chessin et al. J Amer Coll Surg 1997;185:105-13. ++Vignali et al. J Amer Coll Surg 1997;185:105-13. ^ Mac Rae HM et al, Dis colon Rectum. 1998 ^^ Lustosa SA et al. , Sao Paulo Med J. 2002.

Cochrane Review of Literature 2005 Main findings regarding laparoscopic method: Length of stay 1.5 days shorter Incidence of wound infection lower (4.6% vs. open 8.7%, p=0.002) No difference in anastomotic leak or abscess rate Mortality similar Quality of life better up until POD 30

How to Decrease Leak Rate: Blood Supply Must determine each patient’s anatomy Check for anatomic variations (common) Vascular anatomy largely determines resection margins When possible, palpate pulses, check for bleeding (extracorporeal anastomoses) Does patient have atherosclerosis, DM ? Prior Aortic aneurysm (is IMA open) ?

Anastomotic Leaks The bane of the GI surgeons existence They occur regardless of the construction method Extraperitoneal bowel anastomoses have higher leak rates (no serosa) Rectum Esophagus Types of leaks Clinical Radiologic (usually asymptomatic)

Anastomotic Morbidity: Not Just Leaks Abscesses (without documented leak) Fistulas can develop (abscess or leak related) Rate of pelvic infection = leak + abscess Abscess and collection rate not always given Literature hard to assess for this reason No uniform complication reporting system in place

Incidence of Clinical Leaks After Open LAR Series N No. Leaks % Karanjia et al ’94 219 24 11 Zaheer et al ’98 291 16 5 Enker et al ’99 681 8 1.2 Law et al ’00 196 20 10.2 Marijnen et al ’02 1861 214 11.5 Leester et al ’02 249 16 6.4 Wong NY et al ’05 1066 41 3.8 Gastinger et al ’05 2729 390 14.3 Chessin et al ’05 210 8 3.8 Lyall et al ’07 87 10 11.5

Anastomotic Leak After Laparoscopic Colectomy Trial # pts. % leak Franklin ‘96 191 0 Gellman et al ‘96 104 1.9 Lumley et al ‘97 200 2.5 Fielding et al ‘97 285 2.5 Kockerling et al ‘99 949 4.5 Lacey et al ‘97 116 0.9 Regados et al ‘98 146 2.7

Level of Devascularization for Left Sided Colorectal Resections In cancer setting: IMA at origin (+ IMV)  best colon mobility OR Sigmoidal artery, distal to left colic takeoff Diverticular disease: Mid-mesenteric division preserves IMA blood supply to rectum Also protects pelvic nerves Downside: rectum not as well mobilized

Splenic Flexure Mobilization For vast majority of left sided resections Medial mobilization of mesentery Detach omentum Can detach base of distal transverse mesocolon Provides better vascularized colon

Prevention of Leak: Splenic Flexure Mobilization Lower leak rate when descending colon used for anastomosis (vs sigmoid) 15 % with takedown vs 31 % * Less tension Well accepted that flexure should be mobilized for vast majority of LAR’s * Karanja ND et al. Br J Surg 1994;81:1224-6.

Tension: Rectal Mobilization (for LAR) To level of pelvic floor (levators) TME (circumferential dissection) Preserve nerves Full mobilization increases the “reach” of the remaining rectum

Laparoscopic Technique Points for Sigmoidectomy and LAR Check mobility of proximal bowel intracorporeally prior to exteriorization (will it reach to rectum?) Select proximal transection point intracoroporeally. Must consider bowel: Mobility Blood supply Use loop suture to mark transection site Once bowel is exteriorized it is hard to determine what will reach

Technique Point: Choosing Site of Incision for Specimen Extraction Make sure proximal bowel will reach wound and can be exteriorized: Obese lower abdominal wall is thick Pfannenstiel’s incision can be placed too low May be difficult to put in EEA anvil if bowel cannot be well exteriorized

LAR: Exteriorization of Proximal Bowel Colon will not reach Incision too low in this patient !!

LAR: Exteriorization of Proximal Bowel Colon reaches Incision made higher

After Rectal Transection Insert EEA Sizers Into Hartmann’s Pouch If you cannot fully insert sizer to Hartmann linear staple line: Rectal mesentery may not be adequately cleared from linear staple line Carefully clean 1-11/2 cm of posterior & lateral wall Peritoneum covering the rectum anteriorly & laterally may impair stapler insertion Score peritoneum in several places Do further dissection / mobilization and then re-insert

Anastomosis: Orientation of Mesentery Avoid twist of mesentery Follow free cut edge of the mesentery proximally AND Follow anti-mesenteric surface of bowel as well Easier to twist bowel when working laparoscopically

Testing Anastomotic Integrity After rectal transection ? After circular stapled anastomosis Method: Flexible sigmoidoscope with CO2 insufflation Proctoscope Bulb syringe (if desperate) Air pumped into rectum & fluid in pelvis OR Betadine solution into rectum with dry pelvis

Technique Point: After Anastomosis, Prior to Completion: Medial to lateral methods leave mesenteric windows Small bowel can get trapped under mesentery or in window Want free edge of colon mesentery directly overlying retroperitoneum Small bowel underneath the free mesenteric edge will increase tension & can decrease the blood supply

Proximal Diversion of Fecal Stream Limits consequences of leaks Choice of diversion: Colostomy Less output • Harder to close Larger stoma, bulky Ileostomy Higher output • Smaller, less bulky Easier to make and close Loop stomas most commonly made

Proximal Diversion: Preop Mark Possible Stoma Locations Mark sites with patient sitting in chair Avoid skin creases and deep folds Keep 4 fingerbreadths away from umbilicus Mark on right and left Place port at stoma, if possible Place other ports at least 4-5 cm away

Low Anterior Resection: Site Chosen for Loop Ileostomy Umbilicus Planned ileostomy site

Low Anterior Resection: Port Site Locations: Option 1

Low Anterior Resection: Port Site Locations: Option 2

Impact of Diversion at Time of LAR Prospective study, n= 2,729 patients 881 patients diverted at initial op Leaks (+ stoma = 14.5%; - stoma = 14.2%) Lowers chance of requiring laparoscopy / laparotomy (3.6 vs 14.2 % in non-diverted pts) Lower mortality (0.9 vs 2% in non-diverted, p=0.0310) Morbidity of closure (ileostomy, 22.4% vs colostomy, 15.4%, p=0.031) * Gastinger et al Br J Surg 2005;92:1565-6.

Anastomotic Reinforcement Types of reinforcing materials: Fibrin glue, fibrinogen, (“paint” anastomosis) Polyglycolic acid/trimethylene carbonate, random fiber (absorbable) L-lactic acid-co-epsilon-caprolactomne (absorbable) Small intestinal submucosa (bioprosthesis) Bovine pericardium & collagen strips (semi-absorbable) PTFE (non-absorbable)

Anastomotic Reinforcement Most involve “sleeve” that is slid onto stapler (GIA and for EEA) Incorporated into the anastomosis Absorbable materials gone in ~ 6 months Goal is to decrease leaks and hemorrhage Limited data available, thus far Absorbable appears better than non-absorbable

Anastomotic Reinforcement: Summary of Studies Pig study, SB stapled anastomosis: greater bursting pressure in submucosa bioprosthesis reinforced group* Rabbit study, hand sewn ‘mosis, polyglycolic acid mesh: higher bursting strength** Human study, 30 pts, no leaks or bleeding noted. Appeared safe + *Downey DM, et al. Obes Surg. 2005 Nov-Dec;15(10):1379-83. **Raboff W, et al. Am Surg. 1994 Oct;60(10):721-7. +Franklin ME, et al. Surg Laparosc Endosc Percutan Tech 2005;15(1):9-13.

Anastomotic Reinforcement: Summary Being used commonly in US for gastric bypass to limit bleeding Being used for colorectal anastomoses Will be hard to show significantly decreased leak rate without doing large randomized, multicenter study What are the oncologic implications? (tumor cell implantation??) Does it impact stenosis rate after EEA? Studies are ongoing.

Low Index of Suspicion: Early Evaluation for Suspected Leak Physical exam and careful digital Abdomen / pelvic CT scan (p/o + rectal contrast) Free air, fluid - Extravasation Collection - Inflammatory changes Contrast enema (gastrograffin) Careful administration of contrast Via foley cath for low anastomoses Transabdominal USG

How to Avoid Leaks: Summary Understand vascular anatomy Adjust devascularization level to pathology IMA at takeoff or after left colic takeoff for cancer Mid mesenteric transection for diverticulitis Utilize well vascularized bowel Mobilize flexure Mobilize rectum well (neoplasms)

How to Avoid Leaks: Summary Determine proximal point of bowel resection intracorporeally Choose extraction site carefully Tension free anastomosis Assess distal left anastomoses (scope, leak test) Distal 1/3 rectum, divert routinely If in question, divert

Impact of Neoadjuvant Therapy on Leak Rates* 87 patients with rectal cancer 37 had full course preop Chemo/RT with operation 6-8 weeks later 10/87 clinical leaks (11.5%) All leaks had neoadjuvant therapy 6/10 leak pts had complete clinical response to RT CR associated with increased leak rate * Lyall et al. Colorectal Dis 2007;9:801-7.

Prevention of Leak: Splenic Flexure Mobilization Lower leak rate when descending colon used for anastomosis (vs sigmoid) 15 % with takedown vs 31 % * Less tension Well accepted that flexure should be mobilized for vast majority of LAR’s * Karanja ND et al. Br J Surg 1994;81:1224-6.

Colonic J Pouch Some studies found lower leak rates* Others found no difference Better blood supply to pouch apex ? Some attribute better results to higher incidence of splenic flexure takedown in J pouch patients. Better functional results x 1 year * Hallbook et al. Ann Surg 1996;224:58-65.

Stenting Anastomoses at LAR With Transanal Tube (to decrease leaks)* 50 LAR patients, All EEA Transanal tube placed in all at initial op Anastomoses checked at 2, 12 weeks via endoscopy 2 clinical leaks (4.2%) 3 asymptomatic leaks (6.3 %) Cannot draw meaningful conclusions * Sterk et al Zentralbl 2001;126:601-4.

Clinical LAR Leaks: Presentation Fever Tachycardia Ileus, anorexia (possible nausea & vomiting) Abdominal pain and tenderness (often absent for extraperitoneal anastomoses) Most result in localized collections and abscesses in the pelvis Sepsis may develop

Clinical LAR Leaks: Treatment Antibiotics, NPO, observation (small leak, no collection) Percutaneous drainage of collection (transabdominal or transgluteal) +/- EUA EUA, placement of transanal drain via defect (distal pelvic small collection, small defect) Exploratory laparoscopy / laparotomy, drainage of collection, placement of drain, proximal diversion + EUA

In OR, Importance of Exam Under Anesthesia & Direct Transanal Inspection Endoscopy / rigid procto Full EUA Gain better understanding of the problem May be able to drain collection and place drain tube transanally In already diverted patients, often all that is needed If abdomen opened must also do EUA

What About Stent at Time of Leak? Soft or hard stent ? Would need to fit snugly yet not decrease blood flow Combined with percutaneous drainage No data thus far University of Missouri study in progress: stenting of esophageal leaks

Impact of Diversion at Time of LAR Prospective study, n= 2,729 patients 881 patients diverted at initial op Leaks (+ stoma = 14.5%; - stoma = 14.2%) Lowers chance of requiring laparoscopy / laparotomy (3.6 vs 14.2 % in non-diverted pts) Lower mortality (0.9 vs 2% in non-diverted, p=0.0310) Morbidity of closure (ileostomy, 22.4% vs colostomy, 15.4%, p=0.031) * Gastinger et al Br J Surg 2005;92:1565-6.

Rate of SBO in Diverted vs Non-Diverted LAR Patients * All had RT/Chemo Diverted at initial op = 119 SBO Diverted group = 21% Non-diverted group = 8 % (p=0.04) * Chessin et al. J Amer Coll Surg 2005;200:876-82.

Closure of Diverting Stoma after LAR Series N Retained Stoma % Nebakken et al ’02 17 5 29.4 Barkley et al ’03 59 5 8 Lefebure et al ’07 52 4 8

LAR Anastomotic Strictures

Anastomotic Strictures: Definitions No uniform criteria exists Cannot pass 2nd finger ? Cannot pass adult colonoscope ? Symptomatic narrowing only ? Poorly tracked and reported Often noted at time of pre-stomal closure Asymptomatic ones dx’ed x 1 year or more Under reported complication

Anastomotic Stricture: Etiology Ischemia Fibrosis Leak related Tumor recurrence related Radiation related IBD related Diversion related * *Graffner HP et al. Dis Colon Rectum 1983;26:87-90.

Incidence of Anastomotic Stricture After LAR Series N No. Strictures % Lyall et al’ 87 1 1.1 Chessin et al ’05 210 7 3.3 Joos et al ’98 83 4 4.8 Bailey et al ’03 59 2 3.4 Balik et al ’07 282 50 17.7 Lazuskas et al ’94 108 1 0.9 Miller et al ’96 103 4 3.8 Shimada et al ’96 30 9 30.0

Anastomotic Stricture: Evaluation Digital exam Endoscopic (biopsies to rule out recurrent cancer) Contrast fluoroscopic study Abdomen / Pelvic CT scan + rectal /p/o contrast Not ideal to evaluate lumen diameter In cancer patients needed to rule out recurrent cancer

Rate of Stricture After Double Stapled EEA Anastomosis* 282 patients (sigmoid + LAR) Routine sigmoidoscopy within 5 months Stricture defined as inability to pass adult colonoscope across ‘mosis (diameter 1.2 cm) Overall incidence 17.6 % (50 strictures) EEA #31 = 13.9 % EEA #28 = 25.8 % Vast majority asymptomatic * Balik et al. Presented at 2007 DDW, submitted for publication

Why Routinely Check Anastomosis Early After LAR ? Will detect stenoses Moderate narrowing can cause symptoms Stacking of BM’s, increased frequency Mild pain Distension (rarely) Will need to be done if patient to undergo colonoscopy in future On occasion will find 2-3 mm openings 1-2 years later (may be asymptomatic)

Treatment of Stricture Digital (for distal ones) Metal dilators Flexible dilators Balloons (via endoscope or along side scope) Division of staple line (extraperitoneal only) Re-resection and anastomosis Diversion (last resort)

Treatment of Distal Stricture Digital dilatation (if within reach) Dilators (metal or flexible) In office (or OR) by MD at first At home by patient for difficult cases Balloon over wire (TTC or esophageal type) Cutting across staple line (in 1-4 places) Circular stapler (total 4 cases reported) * Reoperation (rarely) * Chia et al. Dis Colon Rectum 1991;34:717-9 ** Shimada et al Ann Surg 1996;224:603-8.

Recalcitrant Distal Stenoses Option 1: multiple office dilatations or OR EUA and dilatation Option 2: teach patient to dilate themselves Need to be observed in office doing dilation Daily home dilatations often successful in reducing symptoms and avoiding other Rx Patients often reluctant (understandably)

Stricture Treatment: Through the Channel Balloon Dilatation Works well for majority of strictures beyond reach of finger Must be able to see across stenosis Pass balloon +/- over wire (1 minute inflation/dilatation, 2-3 inflations/session) Balloon size start at 10 mm  12.5 mm In Columbia series 8/25 EEA 31 stenoses required 2 or > Rx 13/24 EEA 28 stenoses required 2 or > Rx Complications = 0 for Columbia series

Treatment of Benign Anastomotic Stricture: Circular Stapler Report 1: 3 patients treated * Use EEA to resect the stenosis With 8-14 mos. follow up, no recurrence noted Report 2: single patient ** Used EEA as well Must be able to get anvil above the ‘mosis * Pabst et al. Dig Surg 2007;24:149-51. **Arak et al. Kurane Med J 2002;49:149-51.

Stenting of Benign Anastomotic Strictures Is an option No data available for use of stents in patients with benign anastomotic stricture Retention rate ? Long term function ? Erosion ? other complications

Resection & Reanastomosis for Stenosis Last resort Carries considerable morbidity and some mortality No guarantee of success Issues of reach, blood supply, tension remain Patient must understand that result might be permanent stoma or serious complications Majority of patients accept stoma Convert ileostomy  colostomy (an option)

Stricture Summary Look for them Routine flexible sigmoidoscopy within 6 months advised Dilate to scope diameter (if above finger reach) with balloon Distal strictures, dilatation with finger or dilator for most Operative treatment for recalcitrant one

Small Intestinal Submucosa (Bioprosthesis) Reinforcement* Pig study Small bowel anastomoses (GIA) ½ reinforced ½ stapled alone Bursting strength significantly greater in reinforced group *Downey DM, et al. Obes Surg. 2005 Nov-Dec;15(10):1379-83.

Polyglycolic acid Mesh: Animal Study * Rabbit study (n=22) Two hand sewn anastomoses per animal Two layered anastomoses 1 anastomosis per animal reinforced Bursting strength determined on POD 4-5 Reinforced anastomoses had significantly higher bursting strength Histology: Well-developed layer of fibroblasts and collagen between the PGAM and bowel wall serosa. *Raboff W, et al. Am Surg. 1994 Oct;60(10):721-7.

Polyglycolic acid/trimethylene carbonate: Human Study 30 patients Variety of anastomoses Ileocolic, 12; colorectal, 15; other, 3 Median follow up = 7 months No leaks, strictures, or bleeding postoperatively Appears safe 2nd study: 159 colorectal ‘moses (no leaks) * Franklin ME, et al. Surg Laparosc Endosc Percutan Tech 2005;15(1):9-13.

Rate of SBO in Diverted vs Non-Diverted LAR Patients * All had RT/Chemo Diverted at initial op = 119 SBO Diverted group = 21% Non-diverted group = 8 % (p=0.04) * Chessin et al. J Amer Coll Surg 2005;200:876-82.

Anastomoses Methods Circular EEA Single staple (2 purse strings) Double staple Side to side stapled (GIA linear stapler) End to side Hand-sewn Colorectal anastomosis Coloanal anastomosis (post mucosectomy) Pressure induced anastomosis