Overview
Definition:
Sigmoid volvulus is a life-threatening condition characterized by the twisting of the sigmoid colon around its mesentery, leading to bowel obstruction and potential ischemia
Detorsion is the manual untwisting of the volvulus, often a temporizing measure
Sigmoidectomy is the surgical resection of the affected segment of the sigmoid colon.
Epidemiology:
It is the most common type of colonic volvulus, accounting for 50-75% of all colonic volvuli
Predominantly affects the elderly (over 60 years) and individuals with chronic constipation, neurological disorders (e.g., Parkinson's disease), or Chagas disease
Prevalence is higher in certain geographic regions like South America, Eastern Europe, and the Indian subcontinent.
Clinical Significance:
Sigmoid volvulus presents as a surgical emergency due to the high risk of bowel infarction, perforation, peritonitis, and sepsis
Prompt diagnosis and management are crucial to prevent mortality and severe morbidity
Understanding detorsion techniques and definitive sigmoidectomy is vital for surgical residents preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Sudden onset of severe, colicky abdominal pain, typically in the left iliac fossa
Abdominal distension, often progressive and marked
Nausea and vomiting, particularly if obstruction is severe
Constipation, with obstipation (inability to pass stool or gas) being a cardinal sign
Early satiety
If ischemic, patients may develop fever, tachycardia, and hemodynamic instability.
Signs:
Marked abdominal distension, with the abdomen appearing barrel-shaped
Tenderness is usually diffuse, but may be localized to the left iliac fossa
Rebound tenderness and guarding suggest peritonitis and potential bowel perforation
A palpable, tense, distended loop of bowel may sometimes be felt
Bowel sounds may be hyperactive initially, then diminished or absent in obstruction
Signs of dehydration and sepsis may be present in advanced cases.
Diagnostic Criteria:
Diagnosis is primarily clinical, supported by characteristic imaging findings
There are no formal diagnostic criteria, but a high index of suspicion in a patient with risk factors and suggestive symptoms/signs leads to prompt investigation
The combination of characteristic symptoms, physical findings, and radiographic evidence confirms the diagnosis.
Diagnostic Approach
History Taking:
Detailed history of onset, duration, and character of abdominal pain
History of constipation, previous episodes of bowel obstruction, or abdominal surgery
Past medical history, including neurological disorders, chronic illnesses, and medication use
Red flags include rapid onset of severe pain, fever, hemodynamic instability, and inability to pass stool or gas.
Physical Examination:
Systematic abdominal examination, including inspection for distension and scars
Palpation for tenderness, guarding, rebound tenderness, and palpable masses
Auscultation for bowel sounds
Rectal examination may reveal an empty rectal vault, confirming distal obstruction.
Investigations:
Plain abdominal X-ray (supine and erect): Classic "coffee bean" or inverted U-shaped loop of distended sigmoid colon in the right upper quadrant or epigastrium
Air-fluid levels may be seen
Barium enema: Historically used, shows a characteristic bird's beak or pointer sign at the site of obstruction
However, it carries a risk of exacerbating the volvulus and perforation, thus less commonly used now
CT scan abdomen: Highly sensitive and specific, showing a dilated sigmoid loop with a point of twist at the base of the mesentery (whirlpool sign), and surrounding collapsed bowel
It also helps assess for complications like ischemia or perforation
Laboratory tests: Complete blood count (CBC) to assess for leukocytosis, electrolyte levels, renal function tests, and arterial blood gases (ABGs) if sepsis is suspected.
Differential Diagnosis:
Other causes of large bowel obstruction: Sigmoid or rectal cancer
Volvulus of other segments (transverse colon, cecum)
Adhesonic obstruction
Diverticular stricture
Acute colitis
Paralytic ileus
Inflammatory bowel disease
Ischemic colitis.
Management
Initial Management:
Bowel preparation: Nasogastric tube insertion for gastric decompression
Intravenous fluid resuscitation to correct dehydration and electrolyte imbalances
Broad-spectrum antibiotics if peritonitis or sepsis is suspected
Analgesia
Close monitoring of vital signs and abdominal examination
Assessment for signs of bowel compromise.
Medical Management:
Non-surgical detorsion: This is often the first-line approach for uncomplicated sigmoid volvulus
It is performed via flexible sigmoidoscopy or colonoscopy to visualize the twisted loop and gently untwist it
This is typically followed by rectal intubation to decompress the colon and prevent recurrence
Success rates are high, but recurrence is common.
Surgical Management:
Indications for surgery: Failure of non-surgical detorsion
Signs of strangulation, perforation, or peritonitis
Recurrent sigmoid volvulus after non-surgical detorsion
Gangrenous bowel found during exploration
Procedures: Sigmoidectomy with primary anastomosis: For viable bowel, the affected sigmoid colon is resected, and the ends are anastomosed
This is preferred when the patient is stable and bowel viability is certain
Sigmoidectomy with end colostomy and mucous fistula: Performed for non-viable bowel, severe contamination, or when primary anastomosis is deemed unsafe due to patient instability or comorbidities
The proximal end is brought out as a colostomy, and the distal end as a mucous fistula
Hartmann's procedure: Similar to the above, but the distal end is closed and the bowel is not brought out as a mucous fistula
It is often used in emergency settings for patients with severe comorbidities.
Supportive Care:
Postoperative care: Close monitoring for signs of anastomotic leak, ileus, infection, or DVT/PE
Pain management
Gradual reintroduction of diet
Mobilization as tolerated
Nutritional support may be required if prolonged ileus or malabsorption occurs
Rectal tube management if left in situ after detorsion
Psychological support for patients undergoing stoma formation.
Complications
Early Complications:
Anastomotic leak
Intra-abdominal abscess
Sepsis and septic shock
DVT/PE
Wound infection
Postoperative ileus
Stomal complications (necrosis, retraction, prolapse)
Injury to adjacent organs during surgery.
Late Complications:
Stomal stenosis
Incisional hernia
Adhesions leading to bowel obstruction
Recurrent volvulus if inadequate resection or inadequate management of underlying predisposing factors
Psychological impact of stoma.
Prevention Strategies:
Prompt diagnosis and aggressive management of sigmoid volvulus to prevent ischemia and perforation
Careful surgical technique during sigmoidectomy and anastomosis
Judicious use of stoma in high-risk cases
Patient education on dietary modifications and bowel habits to reduce constipation
Consideration of elective sigmoidectomy for recurrent volvulus or significant sigmoid elongation.
Prognosis
Factors Affecting Prognosis:
Presence and severity of bowel ischemia or perforation at presentation
Patient's comorbidities and physiological status
Timeliness and success of intervention (detorsion or surgery)
Type of surgical procedure performed
Presence of sepsis.
Outcomes:
With prompt and appropriate management, the prognosis for uncomplicated sigmoid volvulus is generally good
Mortality rates are significantly higher in cases with perforation or gangrene
Patients undergoing sigmoidectomy with primary anastomosis have good long-term outcomes
Those with stomas require adaptation and may require reversal surgery at a later stage.
Follow Up:
Regular follow-up is essential, especially for patients who have undergone non-surgical detorsion, to monitor for recurrence
For patients who have had sigmoidectomy, follow-up aims to detect anastomotic complications, incisional hernias, or stomal issues
Long-term dietary and lifestyle advice is important to prevent recurrence.
Key Points
Exam Focus:
The "coffee bean" sign on plain abdominal X-ray is pathognomonic for sigmoid volvulus
Non-surgical detorsion via colonoscopy is the first-line treatment for uncomplicated cases
Sigmoidectomy with primary anastomosis is preferred for viable bowel in stable patients
Hartmann's procedure or sigmoidectomy with end colostomy is indicated for gangrenous bowel or unstable patients
Recurrence rates after non-surgical detorsion are high.
Clinical Pearls:
Always suspect sigmoid volvulus in elderly patients with acute abdominal pain and distension, especially with a history of constipation
Even if initial X-ray is normal, if suspicion is high, consider CT scan
Rectal intubation after successful detorsion is crucial to prevent immediate recurrence
Assess bowel viability meticulously during surgery
if in doubt, err on the side of caution with a stoma.
Common Mistakes:
Delaying intervention due to misdiagnosis or underestimation of severity
Attempting repeated non-surgical detorsion in the presence of signs of strangulation
Performing primary anastomosis in the presence of gross contamination or compromised bowel
Neglecting to counsel patients on long-term recurrence risk and lifestyle modifications.