Complications - Sigmoid resection, oncological, robotically assisted with medial-to-lateral approach

· Intraoperative complications arise from unintended injury to anatomically adjacent structures.

· The frequency is generally between 2 and 12% for colon procedures.

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

· Obesity

· Previous surgeries

· Adhesive abdomen

· Emergency procedure

· T4 tumor or extensive accompanying inflammation

Bowel injury:

• Frequency 1-3%, necessary adhesiolysis increases the risk to 4-13%
• Possible injury patterns:
  • Superficial serosal injuries
  • Transmural lesions of the bowel wall
  • Thermal damage to the bowel wall using bipolar scissors or ultrasonic dissector, especially in the area of the left flexure.
  • Mesenteric tears with subsequent ischemia of the dependent bowel segment
  • Injury by trocar placement, Veress needle
• Prevention:
  • In recurrent procedures, incision as far as possible outside the scar
  • Open insertion of the first trocar after previous surgeries
  • Grasping the bowel preferably in the area of the taeniae or appendices epiploicae only with atraumatic grasping forceps under vision.
  • No blind coagulations, careful, targeted preparation with ultrasonic scissors/bipolar sealing instruments

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

• Procedure upon recognition:
  • Robotic suturing for serosal lesions and smaller defects
  • For larger defects >1/2 of the circumference or mesonear lesions: robotically assisted resection and anastomosis

Spleen injury

• Injury mechanism: Pulling on the colon or greater omentum during mobilization of the left flexure typically results in inferior or medially located superficial capsular lesions.
• Prevention: Mobilization of the left flexure with great care and under good exposure of the site. Omental adhesions to the splenic capsule should be addressed and resolved early.
• Procedure upon recognition:
  • Coagulation with bipolar current (bipolar forceps), if necessary, apply hemostatic agent (Tachosil, Flowseal, etc.) or fibrin glue.
  • A spleen-preserving therapy should always be pursued, as it is associated with a lower complication rate than splenectomy.

Note: A laparotomy is only necessary in exceptional cases.

Pancreas injury

• Injury mechanism: During mobilization of the left flexure and also during management of the inferior mesenteric vein, one works close to the pancreatic tail and lower pancreatic margin, which can lead to injury.
• Procedure upon recognition:
  • In case of bleeding, proceed similarly to spleen injuries. Coagulation with bipolar current (bipolar forceps), if necessary, apply hemostatic agent (Tachosil, Flowseal, etc.) or fibrin glue.
  • For parenchymal injuries, it is advisable to place a drain to divert secretions in case of a pancreatic fistula and prevent postoperative complications.

Ureter injury

• Injury mechanism: During mobilization of the sigmoid, due to its close anatomical relationship, ureter injury can occur. This includes sharp partial or complete transections as well as electrical injuries.
• Prevention:
  • Preservation of Gerota's fascia
  • Secure identification of the ureter
  • Use of ICG for better visualization

Caution with previous surgeries and adhesions 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 diagnostics
  • Visual examination
• Therapy
  • Stenting and suturing for short-segment injuries

Note: For superficial injuries, laparoscopic suturing can be attempted; otherwise, a small laparotomy directly over the injury site is recommended to suture the ureter under direct vision. In any case, placement of a ureteral stent is indicated.

• Extensive injuries or partial resections require complex urological reconstructions (diversion, contralateral implantation, psoas hitch procedure).

Intraoperative bleeding

• Risk factors:
  • Obesity
  • Altered anatomy due to previous surgeries, inflammation, and tumors
  • Emergency procedures
• Symptoms/Clinical presentation: Depending on the size of the injured vessel and associated blood loss, from intraoperatively uneventful courses to acute shock symptoms (hemorrhagic shock) are possible.
• Diagnostics: Intraoperative visual identification of the bleeding source
• Prevention:
  • Identification of surgery- or patient-related risk factors for bleeding complications
  • Use of ICG for identification of vascular structures
• Therapy
  • Temporary bleeding control by compression with laparoscopic/robotic atraumatic instruments
  • Informing the surgical team and anesthesia
  • Creating the best possible material and personnel situation surgically (vascular surgeon, second experienced surgeon) as well as anesthesiologically (senior physician, blood units, volume, etc.)
  • Transfusion if transfusion criteria are met
• Surgical strategy
  • Injury to muscular or epigastric vessels in the abdominal wall during trocar placement: compression, if necessary, over a filled bladder catheter. U-sutures above and below the trocar insertion site. In case of doubt, enlargement of the incision site and direct suturing, especially in obese abdominal walls.
  • Bleeding from smaller vessels can usually be controlled using bipolar current or ultrasonic scissors and, if necessary, by clipping.
  • For injuries to large vessels (e.g., aorta, vena cava), immediate laparotomy is indicated. Inform anesthesia and provide blood products, if necessary, involve a vascular surgeon and prepare a vascular tray, create anatomical overview, repair the vessel defect.

Caution: Uncontrolled use of the suction device, especially in venous injuries, can significantly but almost imperceptibly increase blood loss. Therefore, compression until readiness for intervention is established and only then targeted use of the suction device for managing the injury

Intraoperative leakage of the anastomosis

• Diagnostics: Performing an intraoperative leak test as a hydropneumatic leak test or as a test with diluted methylene blue solution.
• Therapy: If the leak test is positive, an attempt can be made to suture a small and easily accessible insufficiency. In case of doubt, re-establishment of the anastomosis should be performed. In principle, in the case of intraoperative leakage, the creation of a protective ileostomy should be considered.

Note: Prevention of Postoperative Complications

• The ERAS (Enhanced Recovery After Surgery) concept and fast-track surgery aim to accelerate postoperative recovery, reduce hospital stays, and minimize the frequency and severity of postoperative complications.

• Key goals include reducing postoperative pain, paralytic ileus with nausea and vomiting, bowel obstruction, and infections. In elective colon surgery, studies show a reduction of up to 40%.

Anastomotic Leakage (in elective colon/rectal resections, approx. 3–12%)

Definition: Failure of the suture connection between two bowel segments, resulting in the leakage of intraluminal contents or air. Anastomotic leaks represent the most severe complication after colorectal cancer resections.

Significance:

• Leading cause of postoperative sepsis following colorectal procedures.

• Associated with high morbidity and mortality.

Prevention:

• Tension-free anastomosis.

• Optimal anastomotic technique.

• Adequate perfusion of bowel ends.

• Intraoperative leak testing.

• Restrictive perioperative fluid management.

Note: Fluorescence angiography with ICG (indocyanine green) of the colon, used to visualize perfusion at the anastomotic ends, is intended to reduce this risk.

Symptoms/Clinical Presentation:

Varies from asymptomatic to septic shock, typically occurring between postoperative days 4 and 10:

• Abdominal pain.

• Peritonitis.

• Elevated inflammatory markers, particularly CRP, during the postoperative course.

• Postoperative fever.

• Bowel obstruction progressing to paralytic ileus.

• Sepsis and shock.

• Discolored or feculent drainage fluid.

• Deterioration of general condition.

Diagnostics:

• Laboratory tests: Inflammatory markers, especially leukocytes and CRP, potentially IL-6, PCT; analysis of drainage fluid for amylase/lipase.

• Imaging:

• Ultrasonography, with guided aspiration of free fluid if necessary.

• CT with rectal contrast.

• Other procedures:

• Endoscopy.

• Diagnostic laparoscopy.

Caution: Any deviation from the normal postoperative course should raise suspicion of an anastomotic leak. If there is a well-founded suspicion, an urgent contrast-enhanced CT with rectal contrast or a prompt partial endoscopy (flexible) must be performed.

Therapy:

Conservative Management:

Applicable in individual cases where the patient is clinically stable, and drainage is functioning, especially if a protective stoma is in place:

• Antibiotics (e.g., Tazobactam, Meropenem).

• Dietary restrictions or enteral nutrition if no stoma is present.

• Intravenous fluids, if needed.

• Parenteral nutrition, if required.

• Close clinical monitoring and reevaluation.

Interventional Management:

• Endosponge for low anastomoses.

• Possible endoscopic treatment with clips.

Surgical Management:

Indicated for clinical deterioration, sepsis, or undrained collections:

• Suturing small defects with drainage.

• For larger defects (>¼ circumference): reanastomosis with drainage; always consider a protective stoma.

• Dissolving the anastomosis and creating a Hartmann situation with drainage.

• Intensive care support with sepsis management: Empiric antibiotics for secondary peritonitis (e.g., Meropenem), fluid/electrolyte resuscitation, and organ support therapy if organ failure occurs.

Intraoperative Intestinal Injury:

Symptoms/Clinical Presentation:

• Generally presents similarly to anastomotic leakage, with a potentially insidious onset.

• Notable findings include:

• Abnormal drainage fluid.

• Elevated inflammatory markers.

• Abdominal pain.

• Sepsis.

Prevention:

• Trocar positioning under direct visualization.

• Use atraumatic instruments to handle the bowel.

• Dissection only with clear visualization.

• Insert and remove instruments under direct sight.

• Avoid holding the bowel unless gripping the teniae coli or epiploic appendages.

• Prevent abrupt movements involving the bowel.

• Complete inspection of the bowel after extensive adhesiolysis before closing the operation.

Diagnostics:

• Contrast-enhanced CT: findings may include contrast leakage and/or free or localized air.

Therapy:

• Surgical revision with suturing or segmental resection and reanastomosis.

Abscess Formation (0.7–12%)

Incidence:

Occurs in approximately 1–12% of cases.

Diagnostics:

• Imaging via ultrasonography or CT.

Therapy:

• Dependent on clinical findings:

• Smaller abscesses without clinical signs of infection, identified incidentally, may be monitored and do not necessarily require surgical or interventional treatment.

CAVE: However, intra-abdominal abscesses can be indirect signs of an anastomotic leak. Therefore, when intra-abdominal abscesses are detected, an anastomotic dehiscence must be ruled out.

For cases with signs of infection, interventional drainage of the abscess is the method of choice. This can be performed sonographically or CT-guided, depending on the location and expertise.

In cases of progressive sepsis, alongside supportive therapy (intensive care, antibiotic treatment), surgical source control is required.

Wound Infection

Incidence: 4–30%, depending on definition, diagnostics, and follow-up period.

Classification: According to the CDC (Centers for Disease Control), wound infections are categorized into three types:

• A1: Superficial infections involving only the skin and subcutaneous tissue.

• A2: Deep infections extending to fascia and muscles.

• A3: Infections involving organs.

Prophylaxis:

• Administration of antibiotics up to 30 minutes before the skin incision, with repeat dosing after 4 hours for prolonged surgeries. Continued antibiotics for contaminated wounds.

• First dressing change 48 hours after surgery.

• Prevention of hypothermia.

Therapy:

• Wide opening of the wound and regular irrigation with sterile saline.

• Empiric antibiotic therapy after obtaining cultures, targeting common pathogens such as E. coli and S. aureus.

• Debridement of necrotic tissue.

• Large wounds with cavity formation may be managed with vacuum-assisted therapy.

Postoperative Ileus

Incidence: Up to 25%.

Prevention:

• ERAS protocols and fast-track surgery, emphasizing early mobilization and timely initiation of oral intake.

Therapy:

• Stepwise approach including:

• Chewing gum.

• Laxatives.

• Metoclopramide (MCP)/Erythromycin.

• Neostigmine.

• Relistor (methylnaltrexone) for opioid-induced ileus.

• Diluted contrast medium.

Postoperative Hemorrhage

Incidence: 0.5–3%.

Management Based on Bleeding Location:

Perianal Bleeding

Clinical Features:

• Perianal bleeding, hemoglobin drop, and hemodynamic impairment.

Management:

• Minor perianal bleeding of old blood postoperatively is common.

• For increasing perianal blood loss or fresh bleeding, endoscopic examination and, if necessary, hemostasis are required.

• If the bleeding originates from the anastomosis, primary endoscopic hemostasis with clips is indicated. Revision surgery is rarely necessary.

• Close monitoring of plasma hemoglobin and coagulation status is mandatory.

Intra-Abdominal Bleeding

Clinical Features:

• Bloody drainage fluid.

• Abdominal pain.

• Tense abdomen.

• Hemodynamic instability.

Diagnostics:

• Monitoring hemoglobin, hematocrit, and coagulation parameters.

• Imaging with ultrasonography, and if necessary, contrast-enhanced CT.

Therapy:

• For non-surgical bleeding: Optimize coagulation and consider transfusion.

• For surgical bleeding: Emergency operative revision is required.

Anastomotic Stenosis

Symptoms/Clinical Presentation:

• Irregular bowel movements.

• Paradoxical diarrhea.

• Subileus symptoms.

• Abdominal pain.

Therapy:

• Initial attempt with endoscopic dilation.

• If unsuccessful, surgical reanastomosis.

Scar and Trocar Hernias

Incidence: 5–16%, commonly occurring at the extraction site or as a trocar hernia.

Therapy:

• Surgical repair, ideally after at least six months.

• Use of mesh-based techniques.

Intraoperative Ureter Injury

Symptoms/Clinical Presentation:

• Non-specific symptoms.

• Flank pain.

• Possible fever progressing to sepsis.

• Reduced urine output with significant leakage.

• Urinary obstruction with ligation.

• Hematuria (note: mild hematuria may not be pathological in patients with ureteral stents).

CAVE: Significant drainage of “clear” fluid through drains with simultaneous reduced urine output is a warning sign for ureteral injury.

Diagnostics:

• Creatinine measurement in drainage fluid.

• Serum retention markers.

• Ultrasonography.

• CT urography or excretory urography.

Therapy:

• For superficial injuries, laparoscopic suturing may be attempted.

• Otherwise, a small laparotomy directly over the injury site is recommended to repair the ureter under direct visualization.

• Placement of a ureteral stent is mandatory in all cases.

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

Abdominal Dehiscence/Fascial Insufficiency at Extraction Site

Incidence: Rare after minimally invasive procedures.

Types:

• Incomplete: Skin closure intact.

• Complete: Visible intestinal organs or omentum.

Time of Onset: Typically occurs during the inpatient postoperative course (day 3–9).

Diagnostics:

• Clinical Presentation: Persistent wound secretion, visual diagnosis if bowel loops are exposed.

• Ultrasonography.

Therapy:

• Surgical revision with repeat fascial closure after ruling out intra-abdominal pathology.

CAVE: Fascial insufficiency is often an indirect sign of an intra-abdominal pathology, such as an anastomotic leak, and must be actively ruled out.

Other Postoperatively Identified Complications:

Nerve Injuries:

• Impotentia coeundi (erectile dysfunction).

General Medical Complications:

• Thrombosis/embolism.

• Pneumonia.

• Cardiac complications.

• Urinary tract infections.

• Stroke.