Anterior resection
Appearance
Indications:
[edit | edit source]- 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
- Rectal/sigmoid cancer
Goals
[edit | edit source]- 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
- Oncologic:
Prep:
[edit | edit source]- 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
- Ensure distance above AV has been confirmed pre-op
Set-up:
[edit | edit source]- 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:
[edit | edit source]- 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.
- Lateral to medial when you will be resecting right along the colonic margin (benign)
- 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:
[edit | edit source]- 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:
[edit | edit source]- 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
- Sites of injury
- 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
- Primary repair
- Leak