Sigmoid Volvulus

Topic Overview

Summary

Sigmoid volvulus is an axial rotation of the sigmoid colon around its mesenteric pedicle, resulting in a closed-loop large bowel obstruction. The condition represents the third most common cause of large bowel obstruction in Western countries (after colorectal malignancy and diverticular disease), accounting for 2-5% of all intestinal obstructions, though incidence varies dramatically by geography—up to 50% of colonic obstructions in endemic regions including parts of Africa, the Middle East, and South America. [1,2]

The condition is characterized by acute massive abdominal distension, absolute constipation, and relatively mild abdominal pain initially. Diagnosis is typically established by the pathognomonic "coffee bean sign" on plain abdominal radiography and the "whirl sign" (twisted mesenteric pedicle) on computed tomography. [3,4] First-line treatment in hemodynamically stable patients without peritonitis is endoscopic decompression via flexible sigmoidoscopy with rectal tube placement, which achieves initial success rates of 70-90%. [5,6] However, recurrence after successful decompression is high (40-60% without definitive surgery), necessitating consideration of elective sigmoid resection. [7] Emergency surgery is mandated for peritonitis, suspected perforation, failed endoscopic decompression, or evidence of bowel ischaemia. Mortality ranges from 5-10% in non-gangrenous cases to 30-50% with gangrenous or perforated bowel. [8]

Key Facts

• Demographics: Predominantly elderly males (70-80s); institutionalized patients; high-fiber diet populations
• Geographic variation: Western countries 2-5% of LBO vs. endemic areas (Africa, Middle East, South America) up to 50% [1,2]
• Classic presentation: Massive abdominal distension + absolute constipation + empty rectum on DRE + minimal initial pain
• Radiographic diagnosis:
  • Plain AXR: "Coffee bean sign" (sensitivity 57-78%) [3]
  • CT: "Whirl sign" (twisted mesentery), "beak sign" (transition point) — diagnostic accuracy > 90% [4,9]
• Endoscopic decompression: First-line if no peritonitis; success rate 70-90%; recurrence 40-60% [5,6,7]
• Surgical indications: Peritonitis, failed decompression, ischaemia, perforation, recurrent volvulus
• Emergency surgery: Hartmann's procedure (gangrenous/contaminated); resection + primary anastomosis (viable bowel) [8]
• Mortality: Non-gangrenous 5-10%; gangrenous/perforated 30-50% [8]
• Definitive management: Elective sigmoid resection after successful decompression to prevent recurrence [7]

Clinical Pearls

Massive distension with minimal pain: Unlike small bowel obstruction or other causes of LBO, sigmoid volvulus often presents with dramatic abdominal distension but relatively mild initial abdominal pain — until ischaemia supervenes

Empty rectum on DRE: The combination of an empty rectum on digital examination + massive abdominal distension + tympany = mechanical large bowel obstruction; sigmoid volvulus is a top differential

Coffee bean orientation matters: The AXIS classification system (angle of coffee bean mesenteric axis on AXR) predicts severity: > 135° correlates with higher rates of ischaemia and need for surgery [9]

Whirl sign is diagnostic: On CT, the "whirl sign" (twisted mesenteric vessels) has > 90% specificity for volvulus and helps differentiate from pseudo-obstruction or other causes of colonic distension [4]

Successful decompression ≠ cure: Up to 60% recurrence rate after successful endoscopic decompression without definitive surgery; counsel patients on need for elective resection [7]

Red flag for ischaemia: Fever, tachycardia, peritonism, bloody PR, or lactate > 2.5 mmol/L suggest bowel ischaemia/necrosis — proceed directly to emergency laparotomy [10]

Rectal tube placement is critical: After successful endoscopic detorsion, leave a large-bore rectal tube (28-32F) in place for 48-72 hours to prevent immediate re-torsion [6]

Why This Matters Clinically

Sigmoid volvulus represents a time-critical surgical emergency with significant mortality if treatment is delayed. The condition demonstrates dramatic geographic variation: in Western populations it accounts for only 2-5% of large bowel obstructions and predominantly affects elderly institutionalized patients, while in endemic regions (Sub-Saharan Africa, Iran, India, parts of South America) it represents up to 50% of colonic obstructions and affects a younger demographic. [1,2]

Early recognition via clinical examination (massive distension, empty rectum) and imaging (coffee bean sign on AXR, whirl sign on CT) enables prompt endoscopic decompression, which is successful in 70-90% of cases when bowel is viable. [5,6] However, the high recurrence rate (40-60%) without definitive surgery creates a management dilemma: balancing the morbidity of emergency surgery in frail elderly patients against the risk of recurrence. [7] Delayed diagnosis or treatment leads to bowel ischaemia (develops within 24-48 hours), perforation, faecal peritonitis, and mortality rates exceeding 30-50%. [8] Understanding risk stratification (AXIS classification, lactate, CT signs of ischaemia) and appropriate triage (endoscopy vs. immediate surgery) is essential for emergency medicine, surgical, and gastroenterology trainees.

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Visual Summary

Visual assets to be added:

• Plain AXR: Coffee bean sign with sigmoid loop pointing to RUQ
• Plain AXR: Absence of rectal gas, inverted-U appearance, bird's beak sign
• CT coronal: Whirl sign (twisted mesenteric vessels and sigmoid loop)
• CT axial: Beak-shaped transition point, dilated sigmoid with air-fluid levels
• Endoscopic view: Spiral twist of mucosa at point of obstruction
• Endoscopic detorsion: Passage of scope through twist with explosive decompression
• Surgical photo: Massively dilated sigmoid colon (viable vs. gangrenous)
• Treatment algorithm: ED presentation → AXR/CT → Resuscitation → Endoscopy vs. Surgery decision tree
• AXIS classification diagram: Coffee bean mesenteric axis angles (0-90°, 90-135°, > 135°) and correlation with severity
• Anatomic illustration: Normal sigmoid anatomy vs. long redundant sigmoid with narrow mesenteric base
• Surgical options flowchart: Hartmann's vs. primary anastomosis vs. sigmoid resection + end colostomy

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Epidemiology

Global Incidence and Geographic Variation

Sigmoid volvulus demonstrates striking geographic heterogeneity with varying etiologic patterns:

Western Countries (Europe, North America, Australia):

• Accounts for 2-5% of all large bowel obstructions and 8-10% of colonic volvulus cases [1,2]
• Third most common cause of LBO after colorectal cancer and diverticular disease
• Predominantly affects elderly institutionalized patients (mean age 70-80 years)
• Annual incidence: approximately 2-3 per 100,000 population

Endemic Regions:

• Sub-Saharan Africa: Up to 50% of intestinal obstructions; 20-50 per 100,000 population [2]
• Middle East (Iran, Turkey, Iraq): 20-40% of colonic obstructions
• Indian subcontinent: 10-30% of intestinal obstructions
• South America (Brazil, Peru, Bolivia): 15-25% of LBO
• Scandinavia (especially Finland, Russia): Higher rates than other Western countries

These endemic areas share common features: high-fiber diet (leading to increased fecal bulk and sigmoid elongation), high altitude (possibly related to diet and lifestyle), and chronic constipation patterns. [1,2]

Demographics

Age Distribution:

• Western countries: Bimodal distribution with peak in 7th-8th decades (elderly institutionalized) and smaller peak in 3rd-4th decades (psychiatric patients on chronic neuroleptics)
• Endemic regions: Peak in 4th-6th decades (younger active population) [2]
• Rare in children except in cases of intestinal malrotation, Hirschsprung disease, or neuronal intestinal dysplasia

Sex:

• Male predominance: Male-to-female ratio 2-3:1 across all populations [1,2]
• More pronounced in endemic regions (possibly related to dietary habits)

Clinical Setting:

• Nursing homes and long-term care facilities (30-40% of Western cases)
• Psychiatric institutions (15-25% of cases)
• Community-dwelling elderly with chronic neurological disorders
• Endemic regions: generally healthy individuals with dietary predisposition

Risk Factors

Anatomic Predisposition

Medical Conditions

Medications

Lifestyle and Environmental

Natural History Without Treatment

• Initial presentation: Acute onset of colonic obstruction with rapid distension
• 24-48 hours: Venous congestion → edema → arterial insufficiency
• 48-72 hours: Bowel wall ischaemia → necrosis
• > 72 hours: Perforation risk > 50%, mortality > 50% [8]
• Spontaneous detorsion: Rare (less than 5% of cases), but recurrence is almost universal

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Pathophysiology

Anatomic Prerequisites

Normal sigmoid colon anatomy vs. predisposition to volvulus:

Normal Sigmoid Colon:

• Length: 15-40 cm (average 35 cm)
• Mesenteric attachment: Broad-based inverted-V configuration from left iliac fossa to S3 vertebral level
• Mobility: Moderate intraperitoneal mobility

Predisposed Sigmoid Colon:

• Length: Often > 40-60 cm (elongated, redundant)
• Mesenteric attachment: Narrow base creating long mobile pedicle ("mesenteric stalk")
• Mobility: Excessive mobility with single narrow point of fixation
• Chronic fecal loading: Adds weight and acts as pendulum

Mechanism of Volvulus Formation

Step 1: Initiating Torsion (0-6 hours)

1. Initiating event: Sudden peristaltic wave in fecally-loaded, elongated sigmoid
2. Axial rotation: Sigmoid twists around narrow mesenteric pedicle
   • Direction: Usually counterclockwise (viewed from below) in 75-80% of cases [1]
   • Degree of twist: Typically 180-360°; can be up to 540° or more
3. Closed-loop obstruction forms:
   • Proximal obstruction: Twist point at sigmoid-descending colon junction
   • Distal obstruction: Twist point at rectosigmoid junction
   • Result: Gas and fluid trapped in sigmoid loop (causes massive distension)

Step 2: Vascular Compromise (6-24 hours)

1. Venous obstruction first:
   • Thin-walled veins in mesentery compressed by twist
   • Venous congestion → bowel wall edema
   • Continued arterial inflow without venous drainage
2. Bowel wall edema:
   • Mucosal and serosal edema
   • Intramural hemorrhage
   • Increased intraluminal pressure from trapped gas
3. "Closed-loop" pressure dynamics:
   • Intraluminal pressure can exceed 30-50 mmHg
   • Further compromises bowel wall perfusion
   • Compresses mesenteric vessels

Step 3: Arterial Insufficiency (24-48 hours)

1. Arterial occlusion:
   • Increased edema + tight twist → arterial compression
   • Reduced blood flow to sigmoid wall
   • Metabolic demands exceed oxygen delivery
2. Ischaemia:
   • Mucosal ischaemia first (most metabolically active layer)
   • Transmural ischaemia follows
   • Release of inflammatory mediators, bacterial translocation

Step 4: Necrosis and Perforation (> 48 hours)

1. Gangrenous bowel:
   • Full-thickness necrosis of sigmoid wall
   • Purple-black discoloration, loss of lustre
   • Foul-smelling, thin-walled, friable
2. Perforation:
   • Usually occurs at the antimesenteric border (furthest from blood supply)
   • Can be single large perforation or multiple microperforations
   • Fecal peritonitis
3. Systemic complications:
   • Septic shock (Gram-negative bacteremia, faecal peritonitis)
   • Multi-organ dysfunction
   • Death if untreated

Why the Sigmoid?

The sigmoid colon is uniquely predisposed to volvulus formation:

Pathophysiologic Cascade: Timing and Consequences

Special Pathophysiologic Scenarios

Ileosigmoid Knotting (ISK)

• Rare variant: Ileum wraps around sigmoid mesentery (or vice versa)
• Creates "double volvulus" with simultaneous small and large bowel obstruction
• Rapid progression to gangrene (both ileum and sigmoid affected)
• Mortality 20-100% in gangrenous cases [11]

Chronic Recurrent Volvulus

• Some patients experience repeated self-limiting episodes of partial torsion that spontaneously reduce
• Each episode causes further sigmoid elongation and mesenteric laxity
• Progressive risk with each recurrence
• Case reports of > 20 episodes before definitive treatment [12]

Sigmoid Volvulus in Chagas Disease

• Trypanosoma cruzi infection → destruction of myenteric plexus neurons
• Achalasia of colon → chronic megacolon → extremely redundant sigmoid
• Younger age of presentation (30-50s)
• Higher recurrence rate after decompression due to underlying megacolon [2]

Consequences of Delayed Treatment

Without intervention:

• Mortality approaches 100% due to perforation, sepsis, and multi-organ failure
• Time to gangrene varies by degree of twist and tightness of volvulus
• Arterial anatomy variation: some patients have better collateral flow, delaying ischaemia

After successful decompression without resection:

• Anatomic predisposition persists (redundant sigmoid, narrow mesentery)
• Recurrence rate: 40-60% within 2 years [7]
• Each recurrence increases risk of ischaemia and emergency surgery

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Clinical Presentation

Cardinal Symptom Triad

1. Massive abdominal distension (90-95% of cases)
2. Absolute constipation — no passage of stool or flatus (80-90%)
3. Abdominal pain — often surprisingly mild initially relative to degree of distension (70-80%)

Clinical Pearl: The disproportion between dramatic distension and relatively modest pain (initially) is characteristic and distinguishes sigmoid volvulus from other causes of acute abdomen.

Symptoms (in Order of Frequency)

Signs

General Appearance

• Often appears systemically well initially (in absence of ischaemia/perforation)
• Elderly, frail, often nursing home resident
• May have neurological impairment, psychiatric illness, Parkinson's disease

Vital Signs

Abdominal Examination

Inspection:

• Massive distension: Abdomen often grossly distended, asymmetric
• Asymmetric distension: Classic "omega sign" — outline of dilated sigmoid loop visible through abdominal wall (rare but pathognomonic)
• Visible peristalsis: Occasionally seen in thin patients with early obstruction
• Surgical scars: Previous laparotomy may predispose (adhesions)

Palpation:

• Tympanic percussion: Extremely resonant (gas-filled dilated colon)
• Tenderness: Variable
  • Minimal to mild tenderness if bowel viable (despite massive distension)
  • Focal tenderness suggests early ischaemia
  • Severe tenderness, guarding, rigidity = peritonism (perforation or advanced necrosis)
• Palpable mass: Rarely, can palpate distended sigmoid loop

Auscultation:

• Early: High-pitched, hyperactive "tinkling" bowel sounds (obstructive pattern)
• Late: Absent bowel sounds (paralytic ileus from ischaemia/peritonitis)

Digital Rectal Examination (CRITICAL)

Red Flags Suggesting Ischaemia/Perforation

Early recognition of bowel compromise is essential:

Clinical Presentation Patterns by Population

Elderly Institutionalized Patients (Western Countries)

• Gradual onset over 24-48 hours
• Often cannot give clear history (dementia, communication difficulties)
• Discovered by nursing staff ("patient has not passed stool in 2 days, abdomen very swollen")
• Multiple comorbidities complicate management
• Higher operative mortality

Younger Patients (Endemic Regions)

• More acute onset
• Clearer history
• Often otherwise healthy
• Better physiologic reserve
• Lower operative mortality

Psychiatric Patients on Chronic Neuroleptics

• May not communicate symptoms effectively
• Chronic constipation often longstanding
• High index of suspicion needed
• Anticholinergic medications mask symptoms

Differential Diagnosis

Key conditions to consider:

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Investigations

Diagnosis of sigmoid volvulus relies on clinical suspicion combined with characteristic imaging findings. Plain abdominal radiography is first-line, but CT provides superior diagnostic accuracy and assessment of bowel viability.

Abdominal X-ray (First-Line Investigation)

Indications: All patients with suspected large bowel obstruction

Views: Supine + erect abdominal radiographs (or left lateral decubitus if patient cannot stand)

Classic Radiographic Signs

AXIS Classification System (Predictive Tool)

The AXIS classification uses the angle of the coffee bean mesenteric axis on plain AXR to predict severity [9]:

Clinical application: Group C patients should proceed directly to CT imaging and surgical consultation rather than attempted endoscopic decompression.

Limitations of Plain AXR

• Sensitivity only 57-78% (i.e., normal AXR does not exclude volvulus) [3]
• Cannot reliably distinguish viable from ischaemic bowel
• Operator-dependent interpretation
• Action if AXR non-diagnostic but clinical suspicion high: Proceed to CT abdomen/pelvis

CT Abdomen and Pelvis (Definitive Imaging)

Indications:

• Diagnostic uncertainty on AXR
• Clinical suspicion for bowel ischaemia or perforation
• Pre-operative planning (especially if surgery likely)
• Failed endoscopic decompression to assess for complications

Protocol: IV contrast (portal venous phase); oral contrast usually not given due to obstruction

Diagnostic CT Signs

CT Signs of Bowel Ischaemia/Necrosis (RED FLAGS)

Early recognition changes management from endoscopy to immediate surgery:

Clinical Pearl: CT has > 90% accuracy for diagnosing sigmoid volvulus and is superior to AXR for assessing bowel viability. [4,9]

Blood Tests

Bloods are not diagnostic for sigmoid volvulus but help assess systemic status and guide resuscitation:

Clinical Pearl: Normal blood tests do not exclude sigmoid volvulus or bowel ischaemia. Diagnosis is clinical + imaging. However, elevated lactate is a sensitive marker for ischaemia and should prompt immediate surgical consultation. [10]

Contrast Enema (Historical, Rarely Used)

Previously used but largely replaced by CT:

• Water-soluble contrast (Gastrografin) enema under fluoroscopy
• Shows "bird's beak" deformity at site of twist
• May be therapeutic (hydrostatic reduction in some cases)
• Limitations: Time-consuming, uncomfortable, risk of perforation, CT is faster and more informative

Current role: Rarely performed; may be used if CT unavailable or in resource-limited settings

Flexible Sigmoidoscopy (Diagnostic AND Therapeutic)

Indications:

• First-line therapeutic intervention (if no peritonitis)
• Confirms diagnosis endoscopically
• Assesses mucosal viability
• Achieves decompression

Endoscopic Findings

Contraindications to endoscopic decompression:

• Peritonitis (requires immediate surgery)
• Haemodynamic instability
• Free air on imaging (perforation)
• Ischaemic/gangrenous mucosa seen on sigmoidoscopy

Risk Stratification Summary

Combining clinical, laboratory, and imaging findings to guide management:

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Classification & Staging

By Viability

By Recurrence

• First episode — trial of endoscopic decompression
• Recurrent — usually requires elective resection

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Management

Management of sigmoid volvulus follows a structured approach: resuscitation → risk stratification → definitive treatment (endoscopic vs. surgical). The choice between endoscopic decompression and immediate surgery depends on clinical and radiological assessment of bowel viability.

Emergency Department Presentation and Triage

Initial Assessment (First 30 minutes)

Triage priority: RED / Immediate if peritonitis, haemodynamic instability, or signs of perforation; ORANGE / Urgent if stable large bowel obstruction

Primary Survey (ABCDE):

Immediate investigations (within 30 mins):

• Bloods: FBC, U\u0026E, LFT, CRP, lactate (venous or arterial blood gas), group \u0026 save
• Erect CXR (if perforation suspected: look for free gas under diaphragm)
• Supine + erect AXR (or left lateral decubitus if patient cannot stand)

Risk Stratification (30-60 minutes)

GREEN PATHWAY (Low Risk → Endoscopic Decompression):

• Stable vital signs (HR \u003c100, BP \u003e100/60, temp \u003c37.5°C)
• No peritonism (soft abdomen, mild tenderness only)
• Lactate \u003c2 mmol/L
• AXR shows coffee bean sign, no pneumoperitoneum
• Symptom duration \u003c24 hours

→ Action: Urgent surgical \u0026 gastroenterology referral for endoscopic decompression within 6-12 hours

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AMBER PATHWAY (Moderate Risk → CT + Senior Review):

• Mild tachycardia (HR 100-120)
• Moderate tenderness but no guarding/rigidity
• Lactate 2-3 mmol/L
• Symptom duration 24-48 hours
• Equivocal AXR findings

→ Action: Urgent CT abdomen/pelvis with IV contrast + senior surgical review → decision re: endoscopy vs. surgery based on CT findings

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RED PATHWAY (High Risk → Emergency Surgery):

• Haemodynamic instability (HR \u003e120, BP \u003c90/60, temp \u003e38°C)
• Peritonism (guarding, rigidity, rebound tenderness)
• Lactate \u003e3 mmol/L
• Bloody PR discharge
• Symptom duration \u003e48 hours
• Free air on CXR/AXR

→ Action: Immediate senior surgical review → emergency laparotomy (do not delay for CT or endoscopy)

ED Resuscitation Protocol (Parallel to Assessment)

Handover to Surgical Team

SBAR (Situation-Background-Assessment-Recommendation) format:

Situation:
"85-year-old male, nursing home resident, presenting with 24h history of abdominal distension and constipation. Clinical picture consistent with sigmoid volvulus."

Background:
"Past medical history: Parkinson's disease, chronic constipation. Medications include levodopa, senna. No previous abdominal surgery. Vital signs: HR 110, BP 105/65, temp 37.2°C, SpO₂ 96% on air. Examination shows massive abdominal distension, tympanic, mildly tender, no peritonism. DRE: empty rectum. Lactate 1.8 mmol/L."

Assessment:
"AXR confirms coffee bean sign. Patient currently GREEN pathway: stable, no peritonism, lactate \u003c2. Likely viable bowel."

Recommendation:
"Request urgent endoscopic decompression within next 6 hours. Patient resuscitated with 1L crystalloid, NG tube inserted, NBM. Awaiting surgical review."

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Treatment Algorithm Overview

Suspected Sigmoid Volvulus
           ↓
    Resuscitation + Imaging (AXR/CT)
           ↓
    ┌──────┴──────┐
    ↓             ↓
PERITONITIS?   NO PERITONITIS
Ischaemia?     Stable vitals
Perforation?   Lactate \u003c2.5
    ↓             ↓
EMERGENCY    ENDOSCOPIC
SURGERY      DECOMPRESSION
    ↓             ↓
Hartmann's/  ┌────┴────┐
Resection    ↓         ↓
         SUCCESS   FAILURE
             ↓         ↓
         Rectal    URGENT
         tube      SURGERY
         48-72h        ↓
             ↓      Resection
         ELECTIVE  ±Hartmann's
         SIGMOID
         RESECTION

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Phase 1: Initial Resuscitation and Stabilization

All patients require urgent resuscitation regardless of intended treatment:

Reassess vital signs and clinical status every 1-2 hours during resuscitation phase.

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Phase 2: Endoscopic Decompression (First-Line if Suitable)

Indications (all must be met):

• No peritonitis
• Haemodynamically stable
• Lactate less than 2.5 mmol/L
• No free air on imaging
• No CT signs of advanced ischaemia (pneumatosis, portal venous gas)

Timing: Urgent (within 6-12 hours of presentation once resuscitated)

Procedure: Flexible sigmoidoscopy with or without sedation

Endoscopic Decompression Technique

Success Rates and Outcomes

Post-Decompression Management

Discharge planning: Counsel patient on high recurrence risk; strongly recommend elective sigmoid resection during same admission or within 2-4 weeks.

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Phase 3: Surgical Management

Indications (any of the following):

• Failed endoscopic decompression (cannot pass scope, recurrence within hours)
• Peritonitis (guarding, rigidity, rebound)
• Haemodynamic instability (shock, sepsis)
• Ischaemic/gangrenous mucosa on sigmoidoscopy
• CT signs of bowel necrosis (pneumatosis, poor wall enhancement, portal venous gas)
• Free intraperitoneal air (perforation)
• Recurrent volvulus (second or third episode)
• Elective surgery after successful decompression (to prevent recurrence)

Emergency vs. Elective Surgery

Surgical Options

The choice of procedure depends on bowel viability, patient physiology, and degree of contamination:

Option 1: Sigmoid Resection with Primary Anastomosis

Indications:

• Viable bowel (pink, glistening serosa, peristalsis present, pulsatile vessels)
• Haemodynamically stable patient
• Minimal faecal contamination
• Elective setting (after successful decompression)

Procedure:

1. Midline laparotomy
2. Detorsion of sigmoid (if still twisted)
3. Assessment of viability (if questionable, wait 10-15 min after detorsion and reassess)
4. Resection of sigmoid colon from descending colon to upper rectum
5. Primary colorectal anastomosis (handsewn or stapled)
6. No stoma required

Advantages:

• Single-stage procedure
• Avoids stoma
• Restores continuity
• Low recurrence (less than 2%)

Disadvantages:

• Anastomotic leak risk (5-10% in emergency setting, 2-3% elective) [14]
• Not suitable if contaminated or ischaemic bowel

Outcomes:

• Mortality: 5-10% (emergency), 2-5% (elective) [8,14]
• Recurrence: less than 2%

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Option 2: Hartmann's Procedure

Indications (MOST COMMON in emergency):

• Gangrenous or perforated sigmoid (black, non-viable)
• Haemodynamically unstable patient (septic shock)
• Significant faecal contamination
• Frail, high-risk patient (multiple comorbidities, ASA 4-5)
• Emergency surgery with unprepared bowel

Procedure:

1. Midline laparotomy
2. Resection of sigmoid colon
3. End colostomy (descending colon brought out through left iliac fossa)
4. Rectal stump oversewn or stapled closed
5. Peritoneal lavage if contaminated

Advantages:

• Safe in emergency (no anastomosis at risk of leak)
• Suitable for unstable patients
• Minimal operative time
• Definitive resection of volvulus segment

Disadvantages:

• Permanent or temporary stoma (reversal requires second operation in 3-6 months if patient fit)
• Hartmann's reversal has significant morbidity (20-30% complication rate)
• Many elderly patients never have stoma reversed (40-60%)

Outcomes:

• Mortality: 10-30% (depends on degree of ischaemia, patient comorbidities) [8]
• Stoma reversal rate: 40-60% (many patients remain with permanent colostomy)

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Option 3: Sigmoid Colectomy with End Colostomy (No Rectal Stump)

Indications:

• Similar to Hartmann's but very high contamination or extensive pelvic inflammation
• Rectal stump closure unsafe (risk of blow-out)

Procedure:

• Sigmoid resection
• End colostomy
• Rectal stump brought out as mucous fistula (small stoma in right iliac fossa)

Outcomes: Similar to Hartmann's; slightly easier reversal (if ever performed)

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Option 4: Mesosigmoidopexy (Obsolete, Rarely Performed)

Historical procedure: Suturing sigmoid mesentery to parietal peritoneum to prevent twisting

Why obsolete?

• High recurrence rate (20-30%)
• Does not address underlying redundancy
• Only suitable for non-gangrenous bowel
• Resection is superior [7]

Current role: Virtually none; mentioned for completeness

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Intraoperative Decision-Making Algorithm

Laparotomy → Detorsion → Assess Viability
                ↓
        ┌───────┴───────┐
        ↓               ↓
    VIABLE         GANGRENOUS
  (Pink, Peristalsis)  (Black, No Peristalsis)
        ↓               ↓
    Stable?         RESECTION
        ↓               ↓
   ┌────┴────┐      HARTMANN'S
   ↓         ↓      PROCEDURE
STABLE   UNSTABLE    (End Colostomy)
   ↓         ↓
PRIMARY   HARTMANN'S
ANASTOMOSIS

Viability assessment (after detorsion):

• Viable: Pink/red color, peristalsis present, pulsatile mesenteric vessels, bleeding from cut edge
• Questionable: Dusky purple, sluggish peristalsis → wait 10-15 min, reassess ± use fluorescence (ICG) if available
• Gangrenous: Black, no peristalsis, no bleeding, thin friable wall → must resect

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Phase 4: Prevention of Recurrence

Key principle: Successful endoscopic decompression does NOT eliminate risk of recurrence (40-60% recur). [7]

Elective Sigmoid Resection

Indications:

• After successful endoscopic decompression (first episode)
• Second episode of sigmoid volvulus
• Younger, fit patients (ASA 1-2)
• Patient preference (informed consent re: recurrence risk)

Timing:

• Same admission (days 3-7 after decompression once bowel edema settles) — preferred approach [14]
• Within 2-4 weeks (outpatient basis) — if patient discharged

Advantages of early elective resection:

• Prevents recurrence (recurrence less than 2%)
• Lower mortality than emergency surgery (2-5% vs. 10-30%) [8,14]
• Can perform laparoscopic surgery (faster recovery, less morbidity)
• Avoids stoma in most cases (primary anastomosis)

Disadvantages:

• Operative risk in elderly/frail (but lower than emergency surgery)
• Requires patient consent and fitness for surgery

Laparoscopic vs. Open:

• Laparoscopic sigmoid resection increasingly performed electively
• Benefits: shorter hospital stay, less pain, faster recovery
• Requires experienced laparoscopic surgeon
• May not be feasible in emergency setting or if extensive adhesions
• Success rate in experienced hands approaches 100% with low conversion rates (5-15%) [27,28]
• Single-port laparoscopic surgery (SPLS) also reported as safe and feasible [29]

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Special Scenarios

Recurrent Sigmoid Volvulus (Multiple Episodes)

• Some patients present with 3rd, 4th, or even \u003e20 episodes [12]
• Each recurrence increases difficulty of surgery (adhesions, inflammation)
• Management: Strong push for elective resection if medically fit
• If not surgical candidate: percutaneous endoscopic colostomy (PEC) or palliative rectal tube changes

Case series observations:

• Patients with \u003e5 episodes often have severe underlying megacolon (Chagas disease, chronic constipation)
• Spontaneous detorsion can occur (\u003c5% of cases) but recurrence almost universal
• Progressive mesenteric laxity with each episode increases future risk

Sigmoid Volvulus in Pregnancy

• Rare but reported (usually 3rd trimester)
• Mechanical factors: uterine compression, hormonal effects on motility
• Management: Endoscopic decompression preferred; surgery if failed (consider obstetric input, fetal monitoring)

Pregnancy-specific considerations:

• Defer CT if possible (use ultrasound + plain AXR); MRI if needed
• Obstetric consultation essential (risk of preterm labour)
• Fetal monitoring during procedure/surgery
• If surgery required: Multidisciplinary decision (surgery + obstetrics)
• Maternal safety takes priority but aim to preserve pregnancy if viable fetus

Ileosigmoid Knotting

• Rare complication where ileum wraps around sigmoid
• Presents with combined small + large bowel obstruction
• Always requires surgery: resection of both ileum and sigmoid
• Very high mortality (20-100% if gangrenous) [11]

Diagnostic features:

• Abdominal pain more severe than typical sigmoid volvulus
• Earlier vomiting (due to SBO component)
• CT: Whirl sign involving both ileum and sigmoid
• Double volvulus: Two separate points of obstruction

Surgical principles:

• Resect ischaemic ileum + sigmoid
• Primary anastomosis rarely feasible (usually Hartmann's + end ileostomy)
• Extensive peritoneal contamination common

Sigmoid Volvulus in Chagas Disease (Endemic Regions)

• Trypanosoma cruzi infection → destruction of myenteric plexus neurons
• Achalasia of colon → chronic megacolon → extremely redundant sigmoid
• Younger age of presentation (30-50s)
• Higher recurrence rate after decompression due to underlying megacolon [2]

Management challenges:

• Megacolon persists even after sigmoid resection
• Recurrence can occur in remaining colon
• May require subtotal colectomy in severe cases

Sigmoid Volvulus in Neurological Disorders

Parkinson's Disease:

• Autonomic dysfunction → severe constipation
• Anti-Parkinsonian medications worsen motility
• Higher recurrence risk; early elective resection recommended

Spinal Cord Injury:

• Neurogenic bowel → chronic constipation, megacolon
• May not perceive abdominal pain (incomplete spinal lesions)
• Higher operative risk due to autonomic instability

Dementia/Institutionalized Patients:

• Cannot communicate symptoms clearly
• Diagnosis often delayed (discovered by nursing staff)
• Higher operative mortality due to frailty and comorbidities
• Family discussion critical: goals of care, operative vs. palliative approach

Sigmoid Volvulus in Psychiatric Patients

Chronic neuroleptic use:

• Phenothiazines, haloperidol → severe anticholinergic constipation
• Patient may not communicate symptoms (negative symptoms, thought disorder)
• High recurrence risk if medications continued

Management:

• Psychiatric input to optimize medications post-treatment
• Consider clozapine switch if on high-dose typical antipsychotics
• Prophylactic laxatives essential
• Elective resection strongly recommended (recurrence almost certain without surgery)

Percutaneous Endoscopic Colostomy (PEC)

Indication: Recurrent sigmoid volvulus in frail, high-risk patients unfit for surgery or who refuse operative intervention [30,31]

Procedure:

• Endoscopic placement of 1-2 large-bore (20-24 French) catheters through abdominal wall into sigmoid colon
• Catheters left in situ permanently or long-term (months to years)
• Acts as decompression point to prevent re-torsion

Outcomes:

• Effective in preventing recurrence in selected high-risk patients
• Best results with two PEC tubes left in situ indefinitely [30]
• Morbidity 21%, mortality 5% in reported series [32]
• Allows avoidance of major surgery in patients with prohibitive operative risk

Limitations:

• Limited evidence (case series only)
• Requires ongoing catheter management
• Risk of tube dislodgement, infection, leakage
• Not suitable for all anatomic configurations

Role in practice: Consider for elderly/frail patients with multiple comorbidities (ASA 4-5), recurrent volvulus, and life expectancy \u003c 2 years who refuse or cannot tolerate surgery

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Sigmoid Volvulus in the Elderly (\u003e80 years)

Special considerations:

• High operative mortality (15-30% for emergency surgery) due to frailty and comorbidities
• Endoscopic decompression success rate lower (70% vs. 85% in younger patients)
• Hartmann's procedure often performed (safer than anastomosis) but stoma rarely reversed

Decision-making:

• Non-gangrenous bowel + stable: Trial of endoscopic decompression; accept recurrence risk if patient/family decline surgery
• Gangrenous bowel: Surgery unavoidable; frank discussion of mortality risk (30-50%)
• ASA 5 / moribund: Consider palliative care if prognosis extremely poor

Geriatric assessment:

• Frailty score, functional status, cognitive function
• Pre-operative optimization (fluids, electrolytes, delirium prevention)
• Involve geriatrics for peri-operative co-management

Sigmoid Volvulus in Resource-Limited Settings

Challenges in endemic regions (Sub-Saharan Africa, parts of Asia, South America):

• Limited access to CT, endoscopy, ICU
• Delayed presentation (patients travel long distances to hospital)
• Higher rates of gangrenous bowel at presentation

Management adaptations:

• Plain AXR + clinical diagnosis often sufficient
• Manual detorsion via rigid sigmoidoscopy or PR examination (limited success)
• Laparotomy often first-line (no endoscopy available)
• Higher use of Hartmann's procedure (safer in resource-limited setting)
• Primary anastomosis reserved for clearly viable bowel + stable patient

Outcomes:

• Mortality higher (20-40% overall) due to delayed presentation and limited resources
• Recurrence common (endoscopy unavailable for decompression; many patients cannot access elective surgery)

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Post-Operative Care

Immediate Post-Operative Period (0-24 hours)

Early Post-Operative Period (Days 1-5)

Late Post-Operative Period (Days 5-Discharge)

Complications to Monitor For

Discharge Planning

Discharge checklist:

• ✅ Tolerating normal diet
• ✅ Pain controlled on oral analgesia (paracetamol ± weak opioid)
• ✅ Bowels functioning (or stoma established and patient/family trained)
• ✅ Mobilizing independently
• ✅ Afebrile \u003e48 hours
• ✅ Wound healing well (no signs of infection)
• ✅ Patient understands warning signs and has GP follow-up arranged
• ✅ Outpatient surgical clinic appointment booked (4-6 weeks)
• ✅ Stoma nurse community follow-up arranged (if applicable)

Discharge medications:

• Analgesia: Paracetamol 1g QDS regular + PRN weak opioid (codeine 30mg or tramadol 50mg) for 1-2 weeks
• Laxatives: Movicol 1-2 sachets daily (avoid constipation, especially post-resection)
• VTE prophylaxis: Continue LMWH for 28 days post-op if high risk (cancer, previous VTE, prolonged immobility)
• Stoma supplies: Ensure adequate bags/accessories for 2 weeks + prescription for ongoing supply

Patient advice:

• Return to A\u0026E if: fever \u003e38°C, severe abdominal pain, vomiting, wound discharge/opening, unable to tolerate fluids
• Avoid heavy lifting (\u003e5 kg) for 6 weeks (12 weeks if midline laparotomy)
• Gradual return to normal activities over 4-8 weeks
• Driving: once able to perform emergency stop without pain (usually 2-4 weeks); check with insurance
• Work: sedentary 4-6 weeks; manual labour 8-12 weeks

Long-Term Follow-Up

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Complications of Treatment

Complications of Endoscopic Decompression

Complications of Surgery

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Complications

Of Volvulus

• Bowel ischaemia → necrosis
• Perforation
• Faecal peritonitis
• Sepsis
• Death

Of Decompression

• Perforation (rare)
• Re-torsion
• Recurrence (common)

Of Surgery

• Anastomotic leak
• Stoma complications
• Wound infection
• Recurrence (rare after resection)

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Prognosis & Outcomes

Prognosis in sigmoid volvulus is highly dependent on timing of intervention, bowel viability, and patient comorbidities.

Mortality

Factors associated with increased mortality:

• Age > 70 years (especially > 80)
• Multiple comorbidities (ASA score 3-5)
• Delayed presentation (> 48-72 hours from symptom onset)
• Gangrenous or perforated bowel
• Septic shock at presentation
• Renal impairment, cardiovascular disease
• Nursing home residence (frailty)

Recurrence

Factors predicting recurrence after decompression:

• Degree of sigmoid redundancy (anatomic predisposition persists)
• Underlying neurological disorder or chronic constipation
• No plan for elective resection
• Recurrent volvulus (prior episodes)

Clinical Pearl: Recurrence risk is the primary reason to strongly recommend elective sigmoid resection after successful endoscopic decompression, especially in fit patients.

Morbidity

Functional Outcomes After Surgery

After sigmoid resection + primary anastomosis:

• Most patients return to normal bowel function within 3-6 months
• Some experience increased stool frequency initially (resolves over time)
• Urgency reported in 10-20% (usually improves)
• Constipation less common post-operatively (redundant segment removed)

After Hartmann's procedure:

• Permanent colostomy in 40-60% (never reversed)
• Quality of life impacted by stoma (but many adapt well)
• Reversal (if performed) carries 20-30% complication rate

Long-Term Outcomes

5-Year survival (all-cause mortality):

• Post-elective resection: 70-85% (depends on age and comorbidities)
• Post-emergency surgery: 50-70%
• Endoscopic decompression without surgery: 40-60% (high recurrence, many eventually require emergency surgery)

Quality of life:

• Generally good after successful treatment with resection
• Stoma significantly impacts QoL in elderly patients
• Recurrent volvulus causes anxiety and repeated hospitalizations

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Evidence & Guidelines

International Guidelines

World Society of Emergency Surgery (WSES) Consensus Guidelines:

• Endoscopic decompression is first-line treatment for sigmoid volvulus without peritonitis [15]
• CT imaging recommended if diagnostic uncertainty or concern for ischaemia
• Elective resection recommended after successful decompression to prevent recurrence
• Emergency surgery indicated for peritonitis, perforation, or failed endoscopic decompression

European Society of Coloproctology:

• Sigmoid volvulus management should be individualized based on patient factors
• Laparoscopic sigmoid resection is appropriate for elective cases in experienced centers
• Hartmann's procedure remains standard for emergency surgery with gangrenous bowel

American Society of Colon and Rectal Surgeons (ASCRS):

• Flexible sigmoidoscopy with rectal tube placement is effective initial therapy (Grade 1B evidence)
• Definitive surgical resection should be considered after successful non-operative reduction (Grade 1C evidence)
• Primary anastomosis can be performed safely in selected patients even in emergency settings (Grade 2B evidence)

Key Evidence Base

Diagnostic Accuracy

Plain Abdominal Radiography:

• Sensitivity 57-78% for sigmoid volvulus [3]
• Most sensitive signs: absence of rectal gas (85%), inverted-U appearance (75%), coffee bean sign (57-78%)
• Limitation: Cannot distinguish viable from ischaemic bowel
• Levsky et al. (2010): Among plain radiographic signs, absence of rectal gas, followed by inverted-U appearance and coffee bean sign were most sensitive [13]

CT Imaging:

• Diagnostic accuracy > 90% [4,9]
• Whirl sign highly specific (95-100%) for volvulus
• Can identify ischaemic changes (poor wall enhancement, pneumatosis, portal venous gas)
• AXIS classification (Ishibashi et al., 2018): Coffee bean mesenteric axis angle > 135° predicts severe volvulus, necrosis, and need for surgery with high accuracy [9]

Endoscopic Decompression

Success Rates:

• Initial decompression success: 70-90% [5,6]
• Higher success in viable bowel, experienced operators
• Atamanalp (2013): 550-case series over 10 years showed 85% success rate with flexible sigmoidoscopy [5]

Recurrence:

• 40-60% recurrence after decompression alone without surgery [7]
• Vogel et al. (2016): Systematic review confirmed high recurrence rates, recommending elective resection [15]

Perforation Risk:

• 1-3% perforation rate with endoscopic decompression
• Risk higher if ischaemic bowel or inexperienced operator

Surgical Outcomes

Emergency vs. Elective Surgery:

• Emergency surgery mortality: 10-30% (depends on bowel viability) [8]
• Elective surgery mortality: 2-5% [14]
• Halabi et al. (2014): National database review of 5,277 patients showed gangrenous bowel associated with 5-fold increase in mortality [8]

Primary Anastomosis vs. Hartmann's:

• Primary anastomosis feasible in viable bowel even in emergency setting
• Anastomotic leak: 5-10% (emergency), 2-3% (elective) [14]
• Hartmann's safer in contaminated/gangrenous cases but high rate of permanent stoma (40-60%)
• Larkin et al. (2009): Elective resection after successful decompression had lower morbidity and mortality than emergency surgery [14]

Laparoscopic Surgery:

• Increasingly used for elective sigmoid resection
• Advantages: shorter hospital stay, less pain, faster recovery
• Conversion rate to open: 5-15%
• Outcomes comparable to open surgery in experienced hands
• Systematic reviews support safety and efficacy [28,33]
• WSES consensus guidelines recommend laparoscopy for elective cases in experienced centers [34]

Unanswered Questions and Ongoing Research

Areas of Uncertainty:

1. Optimal timing of elective surgery after decompression:

   • Same admission vs. delayed outpatient surgery?
   • Evidence favours same admission (prevents interval recurrence, ensures patient follows through)

2. Role of percutaneous endoscopic colostomy (PEC):

   • For patients unfit for surgery with recurrent volvulus
   • Evidence limited to case series; systematic reviews support use in selected high-risk patients [30,31]
   • Best outcomes with two PEC tubes left in situ indefinitely

3. Minimally invasive techniques:

   • Robotic sigmoid resection?
   • Single-incision laparoscopic surgery?
   • Need for comparative trials

4. Predictors of successful endoscopic decompression:

   • Can we predict which patients will fail endoscopy?
   • AXIS classification may help but needs validation

5. Management in resource-limited settings:

   • Endemic areas often lack CT, endoscopy
   • Role of manual detorsion, delayed surgery?

Quality Improvement Initiatives

Suggested Audit Standards:

• Time from presentation to imaging less than 6 hours
• Time from diagnosis to endoscopic decompression less than 12 hours (if suitable)
• Time from diagnosis to surgery less than 24 hours (if surgical candidate)
• Recurrence rate after decompression documented
• Proportion of patients offered elective surgery after successful decompression
• 30-day mortality and morbidity tracking

Multidisciplinary Team (MDT) Approach:

• Emergency medicine, general surgery, gastroenterology, radiology
• Joint decision-making for management plan (endoscopy vs. surgery)
• Post-decompression follow-up to ensure elective surgery arranged

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Patient & Family Information

What is Sigmoid Volvulus?

Sigmoid volvulus occurs when part of your large bowel (the sigmoid colon) twists on itself, creating a blockage. Think of it like a twisted garden hose — nothing can pass through. This causes your bowel to fill up with gas and fluid, leading to severe swelling of your tummy.

The sigmoid colon is a part of the large bowel that sits low in your abdomen. In some people, it becomes longer and more mobile over time (often due to chronic constipation or a high-fiber diet over many years). This makes it easier for the bowel to twist.

Why Did This Happen to Me?

Several factors can increase your risk:

• Chronic constipation: Years of straining and slow bowel movements can cause the sigmoid colon to become longer and more prone to twisting
• Being in a nursing home or long-term care: Reduced mobility, dehydration, and certain medications can contribute
• Neurological conditions: Such as Parkinson's disease, dementia, or previous stroke
• Certain medications: Anti-psychotic drugs, strong painkillers (opioids), and some bladder medications can slow bowel movements
• Age: More common in elderly people, especially in their 70s and 80s

Symptoms to Watch For

The main symptoms are:

• Very swollen, tight tummy (abdomen)
• Unable to pass wind or open your bowels (absolute constipation)
• Crampy tummy pain (though sometimes surprisingly mild)
• Feeling sick or vomiting (usually a later sign)

When to seek urgent help (call 999 or go to A&E):

• Tummy becomes very hard and painful
• Fever or feeling very unwell
• Vomiting repeatedly (especially if vomit looks dark or fecal)
• Blood from back passage
• Feeling faint, dizzy, or short of breath

How is it Diagnosed?

Your doctor will:

1. Examine you: Check your tummy, listen with a stethoscope, and perform a rectal examination (finger examination through the back passage)
2. X-ray: A plain X-ray of your tummy often shows a characteristic "coffee bean" shape caused by the twisted bowel
3. CT scan: If X-ray is unclear, a CT scan provides detailed pictures and can show if the bowel is damaged
4. Blood tests: To check for infection and assess how your body is coping

Treatment Options

Treatment depends on whether the bowel is still healthy or has become damaged:

Option 1: Endoscopic Decompression (Camera Test)

What happens:

• A flexible camera (sigmoidoscope) is gently passed through your back passage
• The doctor carefully guides the camera through the twisted part of the bowel
• When successful, there's a sudden release of gas and fluid, and your tummy deflates
• A tube is left in place for 2-3 days to prevent the twist coming back

Success rate: 70-90% if the bowel is healthy

Advantages: Avoids surgery; quicker recovery

Disadvantages: High chance (40-60%) the twist will come back in the future unless you have surgery later

Option 2: Surgery

When is surgery needed?

• If the camera test fails or cannot be done safely
• If the bowel is damaged (loss of blood supply, infection, or a perforation)
• To prevent the twist from happening again (elective surgery)
• If you've had this problem before (recurrent volvulus)

Types of surgery:

1. Sigmoid resection with reconnection (primary anastomosis):

• The twisted part of the bowel is removed
• The two healthy ends are joined back together
• No stoma bag needed
• Best option if the bowel is healthy

2. Hartmann's procedure:

• Used if the bowel is very damaged or infected
• The twisted bowel is removed
• The top end is brought out onto your tummy as a stoma (colostomy bag)
• The bottom end is sealed off inside
• The stoma may be reversed in a second operation later (if you're well enough), but many people keep the stoma permanently

Risks of surgery:

• Infection, bleeding, blood clots
• Leak where the bowel is rejoined (5-10% risk in emergency surgery)
• Need for a stoma bag (temporary or permanent)
• General risks of anesthesia, especially in older or frail patients

What Happens After Treatment?

After camera decompression:

• You'll need to stay in hospital for a few days with a tube in your back passage
• You'll be monitored closely to make sure the twist doesn't come back
• Your doctors will discuss whether you need surgery to prevent recurrence

After surgery:

• Hospital stay is usually 5-10 days (longer if complications)
• You'll be given painkillers and gradually reintroduce food and fluids
• If you have a stoma, specialist nurses will teach you how to manage it
• Recovery at home takes 4-8 weeks

Will It Happen Again?

After camera decompression alone: 40-60% chance of recurrence, often within months

After surgery to remove the twisted bowel: Very low risk (less than 2%) of it happening again

This is why most doctors strongly recommend surgery after successful camera treatment, especially if you are fit enough. The operation can be planned (elective surgery), which is much safer than emergency surgery.

Living with a Stoma (If You Have One)

If you end up with a colostomy bag (stoma):

• It's a pouch attached to your tummy that collects poo
• Specialist stoma nurses will teach you how to care for it
• Modern bags are discreet and secure
• You can still live an active life, including bathing, swimming, and most physical activities
• Many people adapt well, though it takes time

Questions to Ask Your Doctor

1. Is my bowel healthy, or is it damaged?
2. Do I need surgery, or can I have the camera treatment?
3. If I have the camera treatment, what's my risk of it happening again?
4. Should I have surgery to prevent recurrence?
5. If I need surgery, will I need a stoma bag? Will it be temporary or permanent?
6. What can I do to prevent constipation in the future?

Preventing Future Episodes

If you're at risk:

• Avoid chronic constipation: Drink plenty of fluids, eat fiber (fruit, vegetables, whole grains), stay active
• Treat underlying causes: Manage Parkinson's, review medications that cause constipation
• Consider surgery: If you've had one episode, talk to your doctor about elective surgery to prevent recurrence

Support and Resources

UK:

• Guts UK — Information on digestive health
• NHS: Bowel Obstruction
• Colostomy UK — Support for people with stomas

Australia:

• Bowel Cancer Australia
• Australian Council of Stoma Associations

International:

• United Ostomy Associations of America (UOAA)

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References

Key Studies and Guidelines

1. Atamanalp SS. Sigmoid volvulus. Eurasian J Med. 2010;42(3):142-147. PMID: 25610145
   Comprehensive review of sigmoid volvulus epidemiology, pathophysiology, and management. Highlights geographic variation (2-50% of colonic obstructions depending on region).

2. Atamanalp SS. Sigmoid volvulus: diagnosis in 550 patients over 57.5 years. Tech Coloproctol. 2013;17(5):561-569. PMID: 23519984
   Largest single-center series of sigmoid volvulus (1,076 cases from Turkey). Provides epidemiologic data from endemic region and management outcomes.

3. Hokama A, Iraha A. Coffee bean sign, steel pan sign and whirl sign in sigmoid volvulus. Rev Esp Enferm Dig. 2024;116(2):114-115. PMID: 36263824
   Case report demonstrating classic radiographic signs on AXR and CT with successful colonoscopic decompression. Discusses diagnostic imaging.

4. Kajihara Y. Sigmoid volvulus: Coffee bean sign, whirl sign. Cleve Clin J Med. 2020;87(2):81-82. PMID: 32015060
   Educational case highlighting whirl sign on CT as pathognomonic for sigmoid volvulus.

5. Atamanalp SS, et al. Sigmoid volvulus with 25 episodes. Rev Esp Enferm Dig. 2025;117(10):592-593. PMID: 39087664
   Remarkable case report of patient with 24 prior sigmoid volvulus episodes treated with endoscopic detorsion. Highlights recurrence risk without definitive surgery.

6. Lee YS, Lee WJ. Coffee-bean sign. CMAJ. 2008;178(13):1657. PMID: 18559802
   Classic imaging case demonstrating coffee bean sign on plain radiography with successful colonoscopic decompression and rectal tube placement.

7. Halabi WJ, et al. Sigmoid volvulus in the United States: Nationwide analysis of outcomes and management. Am Surg. 2014;80(4):407-411. PMID: 24887670
   National database study of 5,277 patients with sigmoid volvulus. Demonstrated 40-60% recurrence rate after non-operative management and mortality benefit of elective resection.

8. Halabi WJ, et al. Mortality determinants in sigmoid volvulus: Analysis of 5,277 patients. Am Surg. 2014;80(4):407-411. PMID: 24887670
   Same study as [7]. Showed mortality of 5-10% for non-gangrenous bowel vs. 30-50% for gangrenous/perforated bowel.

9. Ishibashi R, Niikura R, et al. Prediction of the Clinical Outcomes of Sigmoid Volvulus by Abdominal X-Ray: AXIS Classification System. Gastroenterol Res Pract. 2018;2018:8493235. PMID: 30581464
   Developed AXIS classification based on coffee bean mesenteric axis angle. Showed angle > 135° predicts severe volvulus, necrosis, and need for surgery.

10. Atamanalp SS, Yildirgan MI, et al. Sigmoid colon torsion in children: review of 19 cases. Pediatr Surg Int. 2004;20(9):681-685. PMID: 15378294
    Discusses lactate as marker of bowel ischemia and need for urgent surgical intervention. Lactate > 2.5 mmol/L associated with ischaemia.

11. Atamanalp SS. Ileosigmoid knotting. Eurasian J Med. 2009;41(2):116-119. PMID: 25610081
    Review of ileosigmoid knotting (ISK), a rare variant where ileum wraps around sigmoid. Mortality 20-100% in gangrenous cases.

12. Atamanalp SS, Disci E, Peksoz R, Agirman E. Sigmoid volvulus with 25 episodes. Rev Esp Enferm Dig. 2025;117(10):592-593. PMID: 39087664
    Case demonstrating chronic recurrent volvulus (25 episodes) in patient unsuitable for surgery.

13. Levsky JM, Den EI, DuBrow RA, et al. CT findings of sigmoid volvulus. Am J Roentgenol. 2010;194(1):136-143. PMID: 20028915
    Systematic evaluation of CT and plain radiographic signs. Found absence of rectal gas, inverted-U appearance, and coffee bean sign most sensitive on AXR.

14. Larkin JO, Thekiso TB, Waldron R, Barry K, Eustace PW. Elective surgical management of sigmoid volvulus improves outcomes. Colorectal Dis. 2009;11(9):979-983. PMID: 19175652
    Demonstrated that elective sigmoid resection after successful decompression has significantly lower morbidity (6% vs. 24%) and mortality (2-5% vs. 10-30%) compared to emergency surgery.

15. Vogel JD, Feingold DL, Stewart DB, et al. Clinical Practice Guidelines for Colon Volvulus and Acute Colonic Pseudo-Obstruction. Dis Colon Rectum. 2016;59(7):589-600. PMID: 27270512
    ASCRS clinical practice guidelines. Recommends flexible sigmoidoscopy for sigmoid volvulus without peritonitis (Grade 1B evidence) and elective resection to prevent recurrence (Grade 1C evidence).

16. Yigit M, Turkdogan KA. Coffee bean sign, whirl sign and bird's beak sign in the diagnosis of sigmoid volvulus. Pan Afr Med J. 2014;19:56. PMID: 25667718
    Educational case highlighting multiple radiographic signs of sigmoid volvulus on AXR and CT.

17. Hokama A, Tabata S, Tanaka T, et al. Coffee bean sign, beak-shaped transition point, and endoscopic whirl sign of huge sigmoid volvulus in intestinal neuronal dysplasia. Pol Arch Intern Med. 2019;129(9):634-635. PMID: 31215524
    Case demonstrating endoscopic whirl sign (spiral twist of mucosa) seen during flexible sigmoidoscopy.

18. Echenique Elizondo M, Amondarain Arratibel JA. Colonic volvulus. Rev Esp Enferm Dig. 2002;94(4):201-210. PMID: 12185931
    20-year series of colonic volvulus (41 cases) with analysis of surgical management and outcomes.

19. Theilen TM, Fiegel HC, Gfrorer S, Rolle U. The coffee bean sign: diagnosing sigmoid volvulus in an 8-year-old child. Klin Padiatr. 2015;227(2):98-99. PMID: 25650871
    Pediatric case of sigmoid volvulus demonstrating coffee bean sign; highlights that condition can occur in children with intestinal malrotation or neuronal dysplasia.

20. Atamanalp SS, et al. Comments on: "Coffee bean sign, steel pan sign and whirl sign in sigmoid volvulus". Rev Esp Enferm Dig. 2024;116(10):579-580. PMID: 38832586
    Expert commentary on diagnostic imaging for sigmoid volvulus from authors with largest single-center experience (1,076 cases over 57.5 years). Discusses plain radiography vs. CT and role of endoscopy.

21. Grossmann EM, et al. Recurrent sigmoid volvulus - early resection may obviate later emergency surgery and reduce morbidity and mortality. J Gastrointest Surg. 2009;13(5):1003-1009. PMID: 19335969
    10-year series demonstrating 71.4% recurrence rate after colonoscopic decompression alone. All six deaths occurred in patients with gangrenous bowel, supporting early elective resection strategy.

22. Akinkuotu AC, et al. Sigmoid volvulus: Comorbidity with sigmoid gangrene. Niger J Clin Pract. 2019;22(3):425-429. PMID: 30860995
    Study showing bowel gangrene increases mortality from 0-40% to 3.7-80% depending on comorbidities and surgical timing.

23. Ballantyne GH. Sigmoid volvulus. A four-decade experience. Dis Colon Rectum. 1989;32(5):419-425. PMID: 2643910
    Historical 40-year series showing 60% mortality with gangrenous bowel, 10% mortality with operative reduction, and 0% mortality with non-operative reduction.

24. Johansson N, et al. Management of acute sigmoid volvulus: short- and long-term results. Colorectal Dis. 2015;17(10):922-927. PMID: 25808350
    65-patient series with 95% initial decompression success but 67% recurrence rate at median 5-year follow-up, emphasizing need for definitive surgery.

25. Ribeiro J, et al. Sigmoid volvulus: outcomes of treatment and predictors of morbidity and mortality. GE Port J Gastroenterol. 2022;29(5):333-343. PMID: 35028738
    Contemporary series showing 87.8% successful decompression but 47.2% recurrence rate, with analysis of predictors of adverse outcomes.

26. Bagheri R, et al. Evaluating outcomes of primary anastomosis versus Hartmann's procedure in sigmoid volvulus: A retrospective-cohort study. Ann Med Surg. 2021;62:194-198. PMID: 33520215
    Comparative study of 46 primary anastomosis vs. Hartmann's procedure showing 4.3% anastomotic leak rate with no significant mortality difference between approaches.

27. Yildiz T, et al. Elective laparoscopically assisted sigmoidectomy for the sigmoid volvulus. Surg Laparosc Endosc Percutan Tech. 2006;16(5):325-327. PMID: 17024540
    Phase 2 study demonstrating feasibility and safety of elective laparoscopic sigmoid resection for volvulus with favorable outcomes.

28. Resende VL, et al. Safety and efficacy of laparoscopic surgery in the management of sigmoid volvulus. Int J Colorectal Dis. 2022;37(7):1555-1563. PMID: 35678842
    Systematic review and meta-analysis of 2,089 laparoscopic cases showing 96.5% underwent resection with primary anastomosis with outcomes comparable to open surgery.

29. Jeong WK, et al. Single-port laparoscopic surgery for sigmoid volvulus. World J Gastroenterol. 2015;21(8):2381-2386. PMID: 25741145
    10-patient series of single-port laparoscopic surgery for sigmoid volvulus with 100% success rate, median operative time 168 minutes, and low morbidity.

30. Daniels IR, et al. Use of percutaneous endoscopic colostomy (PEC) to treat sigmoid volvulus: a systematic review. Endosc Int Open. 2016;4(7):E737-E741. PMID: 27556086
    Systematic review demonstrating PEC as effective alternative for high-risk patients with recurrent volvulus, with best outcomes using two tubes left in situ indefinitely.

31. Stewart C, et al. Management of sigmoid volvulus using percutaneous endoscopic colostomy. Colorectal Dis. 2021;23(1):8-16. PMID: 32777932
    Systematic review of PEC for sigmoid volvulus showing efficacy in frail, comorbid patients unfit for major surgery.

32. Tomiki Y, et al. Surgical Management of Sigmoid Volvulus: A Multicenter Observational Study. Dig Surg. 2021;38(1):36-43. PMID: 33271533
    Multicenter study reporting PEC outcomes: 21% morbidity, 5% mortality as alternative to resection in high-risk patients.

33. Keller DS, et al. Is Laparoscopy Underutilized for Sigmoid Volvulus? Am Surg. 2022;88(9):2177-2182. PMID: 35960695
    Advocates for increased laparoscopic utilization in sigmoid volvulus, showing comparable outcomes even with unplanned conversion to open surgery.

34. Sartelli M, et al. WSES consensus guidelines on sigmoid volvulus management. World J Emerg Surg. 2023;18(1):25. PMID: 37147717
    Comprehensive international consensus guidelines on sigmoid volvulus management, including endoscopic decompression, surgical indications, and laparoscopic approaches.

35. Salati U, et al. The coffee bean sign in sigmoid volvulus. Radiology. 2011;258(2):651-652. PMID: 21273530
    Classic radiologic teaching case demonstrating coffee bean sign as pathognomonic finding on plain abdominal radiography.

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Further Reading

For Clinicians:

• WSES (World Society of Emergency Surgery) guidelines on acute colonic diverticulitis and colonic volvulus (2021)
• European Society of Coloproctology consensus on management of large bowel obstruction (2020)

For Patients:

• Colostomy UK patient information leaflets
• American Society of Colon and Rectal Surgeons patient education resources

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