Editing Anterior resection

== '''Indications:''' ==

** Rectal/sigmoid cancer
*** Margins: 5cm proximally, 1-2cm distally (aim 5cm distally if upper rectal), 1mm circumferentially
*** Aim for 12 or more lymph nodes in specimen
** Recurrent diverticular disease
** Stricture

== '''Goals''' ==

** Oncologic:
*** Histologically negative margins (aim for 2cm gross longitudinal margin for rectal cancers)
*** CME/TME
**** See 'rectal cancer' topic for TME
**** Complete Mesorectal Excision refers to resection of colon and mesocolon within its peritoneal envelope, with implied high arterial ligation
*** Adequate lymphadenectomy (12 lymph nodes)
*** High ligation of IMA (to enable adequate lymphadenectomy)
** Consider low '''and''' high ligation of IMV, to allow enough length for a tension-free anastomosis
** Avoid injury to pelvic autonomic nerve
** Preserve anorectal function

== '''Prep:''' ==

** Ensure distance above AV has been confirmed pre-op
*** >10cm HAR
*** 6-9cm LAR
*** <6cm ULAR
** Mechanical bowel prep and PO antibiotics the day before are probably beneficial - especially mech prep if might need to do colonoscopy on-table. However many colorectal surgeons don't do it. Does making the stool more liquid also make it easier for it to leak out?
** On-table cefazolin + metronidazole
** ?prophylactic ureteral stenting in high-risk patients - obese, bulky tumours, reoperations, radiotherapy, etc
** VTE prophylaxis - controversial, probably doesn't need to happen on-table

== '''Set-up:''' ==

** GA, prep (probably don't need to prep perineum), drape, lithotomy with both arms tucked or left arm out (surgeon at right, assistant at left initially), IV Abx, TEDs + SCDs
** Harmonic/Ligasure
** IDC
** Stand on patient's right - be aware of cables near patient's right neck e.g. Bair hugger as they can be leant on by assistant
** Open: long midline incision (around left of umbilicus to give better access to splenic flexure)
** Lap: 10mm infra-umbilical, 12mm RLQ, 5mm RUQ, 5mm LUQ

== '''Technique:''' ==

** Check liver/peritoneum for mets
** Push omentum above liver. Get bowel out of the way - head down, left side up, fold leaflets away like a book, consider extra fan retractor.
** Adhesiolysis and mobilisation of sigmoid colon

*** '''Lateral to medial''' when you will be resecting right along the colonic margin (benign)
**** Incise along white line of Toldt, working up towards splenic flexure
**** Careful attention to correct plane, first medial to peritoneal sidewall, then anterior to anterior renal fascia (Gerota's)
*** '''Medial to lateral''' when you will be formally ligating IMA (cancer), and provided you can get the bowel out of the way
**** Tent up sigmoid and identify IMA/IMV, at the sacral promontory, where there is an impression at the CME margin. Iliacs will be just behind.
**** Identify ureter prior to ligating IMA
**** Dissect IMA out to 1cm distal from origin and LigaSure/staple/hemolok/suture ligate (LigaSure x3 is a good option, especially in young patients)
**** Ligate IMV adjacently (this is low ligation IMV)
**** Continue medial to lateral - tent up doona over head and make a window, looking for ureter. Stay directly underneath IMA to avoid digging under ureter.

** Ureter and left gonadal vessel identification, if not already seen
** Mobilisation of colon and upper rectum

*** Incise the retroperitoneal fascia medial to ureter, and work across in the presacral space, in a plane anterior to the left presacral hypogastric nerve.
*** Carry dissection across sigmoid mesentery as far as necessary

** Further mobilisation towards splenic flexure if required

*** Need enough length to easily bring it down to pelvis
*** Divide phrenocolic ligament, avoiding spleen and tail of pancreas
*** Divide adhesions between omentum and colon proximally to mid-transverse colon, entering the lesser sac
*** Divide IMV high (next to DJ ligament) if more length is required

** Dissection and division of rectum

*** Select a point for division (good blood supply, free of diverticulae). Clear the mesenteric border for approx. 2cm, but stay fairly close posteriorly, to avoid damaging nerves.
*** TME to 2-5cm below the point of division (if malignancy) - lift sigmoid vertically with Ray-Tec posteriorly, divide the peritoneum on either side. Dissect posteriorly between pre-sacral fascia and mesorectum, preserving the pre-sacral nerves. Dissect anteriorly between seminal vesicles/vagina and rectum to expose the rectovesical fascia. Continue dissecting in avascular plane between mesorectum and pelvic sidewall.
*** Fire TA linear stapler (green 60) across this point

** Colon extraction and division - limited Pfannenstiel or Lanz incision

*** If converting to open with dissection still to be done, do lower midline

** Anastomosis - EEA/sutured

*** See topics under 'anastomosis' and 'stapling'
*** Check marginal artery for pulsatile flow at anastomosis site - if not present, need to go proximal
*** Covering ileostomy if concerns
*** Leak test
**** Suturing over defect
**** Defunctioning stoma
**** Reconstruction of anastomosis

** Consider loop ileostomy and drain

*** For LAR, reduce risk of leak from 28% to 10% with a covering loop ileostomy

** Closure

== '''Post-op instructions:''' ==

** ERAS - clear fluids straight away and cease IVF same day. Upgrade to full diet the next day if tolerating
** Avoid NGT, IDC out ASAP
** Minimise opioids
** Early mobilisation
** Consider extended duration enoxaparin for cancer operations

== '''Complications:''' ==

** Leak
*** See separate topic
** Necrosis of transposed colon
*** Aggressive treatment - creation of terminal stoma
** Low anterior resection syndrome
*** Consequence rather than a true complication (may be present in 80% after LAR)
*** Risk factors
**** TME
**** Colon-anal anastomosis
**** Neoadjuvant chemoradiation
**** Previous leak
*** Presentation
**** Syndrome - frequency, multiple fragmented bowel movements, sensation of incomplete emptying, incontinence, constipation, and diarrhoea
**** Most of the symptoms improve 1 year or more after the resection, but most do have some degree of persisting dysfunction
*** Pathophysiology
**** Multifactorial
**** Injury to internal sphincter
**** Loss of sensitivity of the anorectal mucosa
**** Loss or impairment of the rectoanal-inhibitory reflex
**** Reduction of the capacity of the rectal reservoir
**** Loss of compliance of the transposed colon
*** Treatment
**** Empirical
**** Diet control
**** Loperamide and fibre products
**** Physical therapy including biofeedback
**** Trans-anal irrigation
**** Construction of end stoma can sometimes be necessary as a definitive treatment
** Autonomic nerve injury
*** Sites of injury
**** IMA ligation - pre-aortic sympathetic plexus
**** Sigmoid mobilisation - superior hypogastric plexus
**** TME laterally - inferior hypogastric plexus
**** TME anteriorly - terminal branches pelvic autonomic nerves
*** Injury:
**** Bowel dysfunction - urgency, frequency, incontinence)
**** Sexual dysfunction - erectile dysfunction, retrograde ejaculation
**** Urinary problems - difficulty voiding, incontinence
** Reduced fertility
*** 73% of women with childhood total proctocolectomy/IPAA who desired to become pregnant were able to conceive
*** Probably largely related to adhesions, rather than autonomic damage
** Ureteric injury
*** Key factors site of injury, presence of tension, viability of cut ends
*** Surgical pause
*** Intra-op urology consult
*** Options to temporise if no urologist available:
**** Drain adjacent to injury (perfectly acceptable)
**** Nephrostomy
**** Externalised stent
**** Ureter externalised and sutured to skin
*** Distal injuries (below SIJ):
**** Primary repair if >4cm proximal to VUJ
**** Ureteric reimplantation +/- adjuncts such as psoas hitch
*** Middle injuries (overlying SIJ):
**** Primary repair if possible without tension
**** Reimplantation via Boari flap
**** Reimplant to contralateral ureter - rare
*** Proximal injuries:
**** Primary repair if possible
**** Ileal or appendiceal interposition graft
**** Auto transplantation
**** Nephrectomy
*** Techniques:
**** Primary repair
***** Mobilise
***** Debride ends
***** Spatulate
***** Interrupted absorbable monofilament
***** Stent across join in most cases


[[Category:Colorectal]]