Complications - Rectal resection, robot-assisted with total mesorectal excision (TME)

General principles:

Intraoperative complications arise from unintended injuries to anatomically adjacent structures.

The overall incidence in colon surgeries ranges between 2% and 12%.

Cave: Known risk factors for intraoperative injury to adjacent structures include:

• Obesity

• Previous surgeries

• Adhesive disease (“frozen abdomen”)

• Emergency procedures

• T4 tumors or extensive associated inflammation

Bowel injury:

Incidence: 1%–3%; however, necessary adhesiolysis increases the risk to 4%–13%.

Potential injury patterns:

• Superficial serosal injuries

• Transmural lesions of the bowel wall

• Thermal damage to the bowel wall caused by bipolar scissors or ultrasonic dissectors, particularly near the left colonic flexure

• Mesenteric tears leading to ischemia in the affected bowel segment

• Injuries caused by trocar insertion or the Veress needle

Prevention:

• During reoperations, incisions should ideally be made outside of the previous scar.

• Open insertion of the first trocar after prior surgeries.

• Grasp the bowel, whenever possible, at the taeniae or epiploic appendages, and only with atraumatic grasping forceps under direct vision.

• Avoid blind coagulation; carefully and precisely dissect with ultrasonic scissors or bipolar sealing instruments.

Cave: Ultrasonic scissors and bipolar sealing devices can cause thermal damage for several seconds after active use.

Management upon recognition:

• Robotic suturing for serosal injuries and small defects.

• For larger defects (>1/2 of the circumference) or lesions near the mesentery: robotic-assisted resection and anastomosis.

Splenic Injury

Mechanism of Injury:

During mobilization of the left colonic flexure, traction on the colon or greater omentum typically causes inferior or medial superficial capsular lacerations.

Prevention:

Mobilization of the left colonic flexure must be performed with great care and under optimal exposure of the surgical site. Omental adhesions to the splenic capsule should be released early.

Management upon Recognition:

• Coagulation using bipolar energy (bipolar forceps).

• If necessary, apply a hemostatic agent (e.g., Tachosil, Flowseal) or fibrin glue.

• A spleen-preserving approach should always be pursued, as it is associated with a lower complication rate compared to splenectomy.

Note:

A laparotomy is only required in exceptional cases.

Pancreatic Injury

Mechanism of Injury:

During mobilization of the left colonic flexure and handling of the inferior mesenteric vein, preparation near the pancreatic tail and lower pancreatic border increases the risk of injury.

Management upon Recognition:

• In the case of bleeding, follow a similar approach as for splenic injury: coagulation with bipolar energy (bipolar forceps), application of a hemostatic agent (e.g., Tachosil, Flowseal), or fibrin glue.

• For parenchymal injuries, placement of a drain is recommended to manage pancreatic secretions in the event of a pancreatic fistula and to prevent postoperative complications.

Ureteral Injury

Mechanism of Injury:

During sigmoid mobilization, the ureter may be injured due to its close anatomical relationship to the operative field. Injuries can include sharp partial or complete transections as well as thermal damage.

Prevention:

• Preserve the Gerota fascia.

• Ensure secure identification of the ureter.

• Use indocyanine green (ICG) for enhanced visualization.

Caution in cases of prior surgeries and adhesion formation due to inflammation or tumors with disruption of anatomical layers in the pelvis.

Preoperative stenting of the ureter should be considered to facilitate its identification.

Intraoperative Diagnosis:

• Visual inspection

Treatment:

• Stenting and suturing for short-segment injuries.

• Note: In cases of superficial injuries, laparoscopic suturing can be attempted. Otherwise, a small laparotomy directly over the site of injury is recommended to suture the ureter under direct vision.

• In all cases, placement of a ureteral stent is mandatory.

• Extensive injuries or partial resections require complex urological reconstructions, such as diversion, contralateral implantation, or a psoas hitch procedure.

Intraoperative Bleeding:

Risk Factors:

• Obesity

• Altered anatomy due to previous surgeries, inflammation, or tumors

• Emergency procedures

Symptoms/Clinical Presentation:

Depending on the size of the injured vessel and the associated blood loss, presentations can range from intraoperatively inconspicuous findings to acute shock symptoms.

Diagnosis:

• Intraoperative visual identification of the bleeding source

Prevention:

• Identification of surgery- or patient-related risk factors for bleeding complications

• Use of indocyanine green (ICG) for vascular structure identification

Treatment:

• Temporary bleeding control with compression using laparoscopic/robotic atraumatic instruments

• Inform the surgical and anesthesiology teams

• Ensure optimal material and personnel resources:

• Surgical: vascular surgeon, second experienced operator

• Anesthesiology: attending anesthesiologist, blood products, volume replacement

• Transfusion if transfusion criteria are met

Surgical Tactics:

• Injuries to muscular or epigastric vessels in the abdominal wall during trocar placement:

• Compression, if necessary with a filled urinary catheter

• U-stitches placed above and below the trocar insertion site

• In uncertain cases, extend the incision and place direct sutures, especially in obese abdominal walls

• Bleeding from smaller vessels:

• Usually controlled with bipolar energy or ultrasonic scissors and, if necessary, clipping.

• Injuries to large vessels (e.g., aorta, vena cava):

• Immediate laparotomy is indicated.

• Inform the anesthesiology team and prepare blood products.

• If necessary, involve a vascular surgeon and prepare a vascular instrument tray.

• Ensure clear anatomical exposure and repair the vascular defect.

Cave:

Uncontrolled use of the suction device, particularly in cases of venous injuries, can significantly increase blood loss almost imperceptibly. Therefore, apply compression until readiness for definitive management is achieved, and only then use the suction device in a targeted manner to address the injury.
Intraoperative Leakage of the Anastomosis

Diagnosis:

Perform an intraoperative leak test, either as a hydropneumatic leak test or using diluted methylene blue solution.

Treatment:

• If the leak test is positive and the insufficiency is small and well accessible, an attempt can be made to suture the defect.

• In cases of uncertainty, re-creation of the anastomosis should be performed.

• In general, the creation of a protective ileostomy should be considered in the event of intraoperative leakage.

Prevention of postoperative complications:

• The ERAS concept and fast-track surgery aim to accelerate postoperative recovery, reduce the length of hospital stay, and decrease the frequency and intensity of postoperative complications.
• This primarily involves the reduction of postoperative pain, postoperative bowel atony with nausea and vomiting, as well as stool retention and infections. In elective colon surgery, studies show a reduction of up to 40% in some of the aforementioned target metrics.

Anastomotic leakage

• Frequency: in elective colon/rectum resections, approx. 3-12%, higher in emergencies
• Definition: Leakage of the suture connection between two bowel segments with the exit of intraluminal secretions/intraluminal air. Anastomotic insufficiencies represent the most severe complication after colon cancer resections.
• Significance: most common cause of postoperative sepsis after colorectal procedures, high morbidity and mortality
• Prevention:
  • Tension-free
  • Ideal anastomosis technique
  • good perfusion of the bowel ends
  • Leak test intraoperatively
  • Intra-/perioperative restrictive fluid administration

Note: Fluorescence angiography with ICG (indocyanine green) of the colon/rectum, providing objective assessment of blood flow at the bowel ends to be anastomosed, is intended to reduce this risk.”

• Symptoms/Clinical presentation: variable from asymptomatic to septic shock, period: 5th-9th postoperative day
  • Abdominal pain
  • Peritonitis
  • Inflammatory laboratory values, especially CRP increase postoperatively over time
  • Postoperative fever
  • Passage disorder up to paralytic ileus
  • Up to sepsis and shock events
  • Discolored/stool-like drainage secretion with drainage in place
  • Deterioration of general condition
• Diagnostics:
  • Blood work: inflammatory values, especially leukocytes and CRP, possibly IL6, PCT, drainage secretion: amylase/lipase
  • Ultrasound, possibly puncture of free fluid supported by sonography
  • CT with rectal filling
  • Endoscopy
  • Diagnostic laparoscopy

Note: A low CRP (C-reactive protein) between the 3rd and 5th postoperative day has a relatively high negative predictive value; values > 170 are suspicious in the corresponding clinical context.

Cave: Any deviation from the normal postoperative course should raise suspicion of anastomotic leakage. In case of justified suspicion, immediate endoscopy (flexible) and/or a CT with rectal filling should be performed.

• Therapy:
  • Conservative: in individual cases with clinically asymptomatic patients and drainage, especially with protective stoma possible
    • Antibiotics (e.g. Tazobac, Meronem)
    • Dietary restriction/absorbable diet if no stoma is in place
    • Possibly iv fluids
    • Possibly parenteral nutrition
    • Close clinical reevaluation
• Interventional:
  • Endosponge for deep anastomoses
  • Possibly endoscopic treatment with clip
• Surgical: Always in case of clinical deterioration/septic patient/non-drained findings
  • Suture for small defects + drainage
  • Reconstruction for larger defects > ¼ circumference + drainage
  • Then: always consider protective stoma
  • Dismantling of the anastomosis and creation of a Hartmann's situation + drainage
  • Intensive medical care with sepsis therapy: Calculated antibiotics for secondary peritonitis (e.g. Meronem, fluid/electrolyte balance, organ replacement therapy in case of organ failure)

Intraoperatively missed bowel injury

• Symptoms/Clinical presentation:
  • Generally similar variable clinical presentation as with anastomotic leakage possible, often insidious course
  • abnormal drainage secretion,
  • High inflammatory values
  • Abdominal pain
  • Sepsis
• Prevention:
  • Trocar positioning under vision
  • Atraumatic instruments for grasping the bowel
  • Dissection only under safe vision
  • Insertion and removal of instruments under vision
  • Avoid holding the bowel, if so then at taeniae and appendices epiploicae
  • Avoid abrupt movements with the bowel
  • Complete inspection of the bowel after extensive adhesiolysis before the end of the operation.
• Diagnostics:
  • Contrast-enhanced CT: contrast agent leakage and/or free air/local air
• Therapy
  • Surgical revision with suturing/resection and anastomosis

Abscess

• Frequency: 1-12%
• Diagnostics:
  • Imaging using ultrasound or CT
• Therapy: depending on the clinical findings:
  • Smaller abscesses without clinical signs of infection, diagnosed as incidental findings, should be monitored over time and do not necessarily require surgical or interventional therapy.

CAVE: However, intra-abdominal abscesses can be indirect signs of anastomotic leakage. Therefore, in the presence of intra-abdominal abscesses, a leakage should be excluded.

• In case of signs of infection, the interventional drainage of the abscess is the method of choice. This can be performed sonographically or CT-guided depending on location and expertise.
• In case of progressive sepsis, in addition to supportive therapy (intensive care unit, antibiotic therapy), surgical source control should be pursued.

Wound infection

• Frequency: 4->30% depending on definition, diagnostics, and follow-up time
• Classification: According to CDC (Center for Disease Control), 3 categories are distinguished:
  • A1 superficial infections that only involve the skin and subcutaneous tissue
  • A2 deep infections that extend to fascia and muscles
  • A3 infections with organ involvement
• Prophylaxis:
  • Single-shot antibiotic administration up to 30 min before skin incision and repetition after 4 h with corresponding operation time and continuation in contaminated wounds
  • First dressing change 48 h post-op
  • Use of suction dressings
  • Avoidance of hypothermia
• Therapy:
  • Wide opening of the wound
  • Regular rinsing with sterile saline solution
  • Debridement of necrotic zones
  • Large wounds with pocket formation are suitable for vacuum treatment
  • Possibly calculated antibiotics effective against E. coli and S. aureus, the two most common pathogens of postoperative wound infections, after swab collection

Postoperative bowel atony

• Frequency: up to 25 %
• Prevention: ERAS concept, fast-track surgery with early mobilization and early dietary advancement
• Therapy: Step wise approach 
  • Chewing gum
  • Laxatives
  • MCP/Erythromycin
  • Neostigmine
  • Relistor with morphine administration
  • Diluted contrast agent

Postoperative bleeding

• Frequency: 0.5-3 %
• Diagnostics:
  • Blood work: Hb and Hct
  • Inspection of drainage secretion if drainage is in place
  • Endoscopy in case of suspected endoluminal bleeding
  • Imaging: Ultrasound/Angio-CT in case of suspected intra-abdominal bleeding
• Therapy:
  • Endoscopic hemostasis in case of endoluminal bleeding
  • Discuss interventional therapy options with the interventional radiologist
  • Revisional laparotomy in case of intra-abdominal bleeding without interventional therapy option or with hemodynamic effect
• Note:
  • Postoperatively, there may be anal discharge of small amounts of older blood.
  • In case of increasing anal blood discharge or the occurrence of fresh rectal bleeding, an endoscopic examination should be performed.
  • If there is bleeding at the anastomosis, primary endoscopic hemostasis using a clip is indicated. Only in exceptional cases is a revision surgery necessary. Close monitoring of hemoglobin in plasma and coagulation status is mandatory.
  • In case of bloody secretion through the drainage, monitoring of hemoglobin and coagulation is also indicated. Depending on the extent of the bleeding, the clinical condition, and the hemoglobin level, transfusion of erythrocyte concentrates or surgical revision is indicated. If the clinical condition of the patient allows, a prior angio-CT is advisable.
  • In case of massive postoperative bleeding with circulatory instability, immediate revisional laparotomy is indicated.

Anastomotic stenosis

• Symptoms/Clinical presentation:
  • Irrregular bowel movements
  • Paradoxical diarrhea
  • Subileus symptoms
  • Abdominal pain
  • Therapy:
    • Initially endoscopic dilation attempt
    • if unsuccessful surgical reconstruction of the anastomosis

Scar and trocar hernia

• Frequency: 5 – 16%, in the area of the retrieval incision or trocar hernia
• Therapy: Surgical repair at the earliest after 6 months, mesh-based approach

Intraoperatively missed ureter injury:

• Symptoms:
  • Unspecific
  • Flank pain
  • Possibly fever up to sepsis
  • Reduced urine output with large leakage
  • Urinary obstruction due to ligation
  • Hematuria

Note: With ureter stents in place, some hematuria may not be pathological.

CAVE: Abundant "clear" fluid discharge through the drainage(s) with simultaneously reduced urine output is a warning signal for a ureter injury.

• Diagnostics:
  • Creatinine in drainage secretion
  • Retention values in serum
  • Ultrasound
  • CT urography, excretory urography
• Therapy:
  • In case of superficial injuries, laparoscopic suturing may be attempted; otherwise, a small laparotomy in direct projection on the injury site is recommended to suture the ureter under vision. In any case, placement of a ureter stent is indicated.
  • Extensive injuries or partial resections require complex urological reconstructions (diversion, implantation on the opposite side, psoas hitch plastic).

Abdominal compartment syndrome/fascia insufficiency of the retrieval incision:

• Frequency: rare after minimally invasive procedures
• Forms:
  • Incomplete: intact skin suture
  • Complete: visible intestinal organs/omentum
• Timing: in the inpatient postoperative course (3rd – 14th day)
• Diagnostics/Clinical presentation:
  • Persistently secreting wound, visual diagnosis with visible intestinal loops
  • Ultrasound
  • Possibly CT also to exclude other intra-abdominal pathologies
• Therapy: Surgical revision with renewed fascia closure after exclusion of intra-abdominal pathology

CAVE: Its not uncommon that fascia insufficiency is an indirect sign of an intra-abdominal pathology such as anastomotic leakage, therefore it is important to actively exclude this.

Further postoperative complications:

• Nerve injuries: Impotentia coeundi

General medical complications: Thrombosis/embolism; pneumonia; cardiac complications; urinary tract infection; stroke