Intussusception & Volvulus General surgery

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Intussusception & Volvulus - General Surgery

INTUSSUSCEPTION

Definition & Terminology

Intussusception is the "telescoping" of intestine, where a proximal segment of bowel (the intussusceptum) invaginates into a distal segment (the intussuscipiens). The advancing edge of the intussusceptum is called the lead point.

Bailey & Love's Short Practice of Surgery, 28th Ed.
Fischer's Mastery of Surgery, 8th Ed.

Epidemiology

Feature	Pediatric	Adult
Age peak	6-9 months (range 3 months - 3 years)	Any age, typically older
Incidence	~56/100,000 per year (US)	Rare
Etiology	Mostly idiopathic (>96%)	Almost always pathological lead point
Lead point nature	Viral lymphoid hyperplasia (Peyer patches)	Malignant in ~50% of cases

Types by Location

Ileocolic (most common, >80%) - begins proximal to ileocaecal valve, apex in ascending or transverse colon
Ileoileal - small bowel to small bowel; often transient, self-resolving
Jejunoileal
Colocolic
Ileocaecal - the ileocaecal valve itself may serve as the lead point

Pathophysiology

The invaginating segment carries its mesentery with it. This leads to:

Venous and lymphatic obstruction
Oedema and mucosal congestion ("redcurrant jelly" stool)
Arterial compromise if untreated → ischaemia → gangrene → perforation

Lead Points

Benign (pediatric):

Lymphoid hyperplasia / Peyer patches (post-viral - most common)
Meckel diverticulum
Enteric duplication cyst
Hamartoma (Peutz-Jeghers syndrome)
Cecal polyp
Burkitt lymphoma (rare)
Appendiceal pathology (appendicitis, carcinoid)

Pathological (adult, ~50% malignant):

Colonic or small bowel carcinoma
Lymphoma
Metastatic deposits
Lipoma
Inflammatory polyps

Pathological lead points are more common in children >2 years and with recurrent intussusception.

Clinical Features (Pediatric - Classic Triad)

Colicky pain - episodic, infant draws up legs
Vomiting
"Redcurrant jelly" stool - blood and mucus per rectum (late sign)

Examination:

Between episodes: child initially appears well
Dehydration
Abdominal distension
Palpable right upper quadrant mass (the intussusceptum)
Paucity of gas in right iliac fossa

Investigations

Investigation	Finding
Plain AXR	Small bowel obstruction; soft-tissue mass; paucity of gas in RIF; meniscus sign
Abdominal USS	Concentric "target sign" (axial view); "pseudo-kidney" sign (longitudinal view) - first-line investigation
CT abdomen	Confirms in adults; identifies lead point

Prognostic note: A normal bowel gas pattern on AXR predicts the highest success rate for enema reduction. Obstruction on AXR is associated with significantly lower reduction success rates.

Intraoperative Photo: Ileocolic Intussusception

Ileocolic intussusception at surgery showing the intussusceptum being manually reduced

Ileocolic intussusception causing small bowel obstruction - Bailey & Love's Short Practice of Surgery

Treatment

Resuscitation First (Always)

IV fluids
Broad-spectrum antibiotics
Nasogastric drainage

Non-Operative Reduction (First-line, if no contraindications)

Air (pneumatic) reduction enema - success recognised by air flowing into the small bowel through the ileocaecal valve

Air enema reduction of an intussusception - arrows mark the soft-tissue shadow of the intussusceptum

Air enema reduction - Bailey & Love's Short Practice of Surgery

>70% are reducible non-operatively
A key criterion: reflux of the reduction medium through the ileocaecal valve into the terminal ileum confirms complete reduction
Delayed repeat enema (2-4 hours later) is reasonable if partial reduction was achieved on first attempt

Contraindications to enema reduction:

Peritonitis
Perforation
Haemodynamic shock

Operative Management

Indicated when:

Non-operative reduction fails
Known pathological lead point
Peritonitis or shock
Ischaemia/gangrene (strangulation)

Approach: open or laparoscopic

Irreducible, infarcted, or lead-point-driven intussusception requires bowel resection
Colonic perforation during pneumatic reduction is rare but requires emergency surgery

Recurrence

~5% after non-operative reduction
Recurrence should raise suspicion of a pathological lead point

VOLVULUS

Definition & Pathophysiology

Volvulus is a twist (axial rotation) of a bowel segment about its mesentery.

>180° torsion → luminal obstruction
>360° torsion → vascular occlusion (mesenteric vessels)

Mechanism of ischaemia:

Mechanical twisting obstructs mesenteric veins → thrombosis
Increasing intraluminal pressure (bacterial fermentation/gas) impairs capillary perfusion
Arterial occlusion if torsion is severe enough

Classification

Primary volvulus - congenital cause:

Congenital malrotation of gut
Abnormal mesenteric attachments or congenital bands
Examples: volvulus neonatorum, caecal volvulus, sigmoid volvulus

Secondary volvulus (more common in adults):

Rotation around an acquired adhesion or stoma

Sites of Volvulus

Site	Notes
Sigmoid colon	Most common in adults; requires a mesentery to allow twisting
Caecum	Second most common; requires a hypermobile caecum
Transverse colon	Rare; requires a persistent dorsal mesentery
Splenic flexure	Rare
Small intestine	Neonatal midgut volvulus (life-threatening)

Sigmoid Volvulus

Predisposing Factors

Causes predisposing to sigmoid volvulus - Bailey & Love's Short Practice of Surgery

Three anatomical prerequisites:

Overloaded pelvic colon (elongated sigmoid)
Long pelvic mesocolon
Narrow posterior mesenteric attachment

Additional factors: high-residue diet, constipation, adhesions, chronic psychotropic drug use, pelvic masses, pregnancy

Demographics:

Common in West/East Africa - most common cause of large bowel obstruction in indigenous black African population, seen in younger patients
In Western countries - predominantly elderly, institutionalised, with comorbidities
Rotation is almost always anticlockwise

Clinical Presentation

Massive colonic distension - the key feature
Pain is unusual in sigmoid volvulus; if present, it is a warning sign of ischaemia
History may not always be forthcoming given frailty of typical patients
Can be classified as:
- Fulminant: sudden onset, severe pain, early vomiting, rapidly deteriorating
- Indolent: insidious onset, slow progressive, less pain, late vomiting

Investigations

Plain AXR: Useful but not always diagnostic - shows massive distension of a dilated loop, often appearing as an inverted "U" or "coffee bean" sign

Plain abdominal radiograph showing colonic distension associated with a sigmoid volvulus

AXR: sigmoid volvulus - massive colonic distension - Bailey & Love's Short Practice of Surgery

CT: Mainstay of diagnosis - shows the "whirl sign" (twisted bowel and mesentery, proportional to degree of rotation)

Water-soluble contrast enema: Shows "bird's beak" deformity at the site of the twist

Treatment

Step 1 - Non-operative decompression (first-line):

Rigid sigmoidoscope or colonoscope
Allows direct vision, assessment of mucosal viability, and derotation
On successful derotation: insert a well-lubricated flatus tube and leave for 2-5 days

Findings indicating ischaemia (abandon derotation - immediate surgery):

Bloody bowel contents
Discoloured mucosa
Attempted derotation in this situation risks circulatory collapse and death

Step 2 - Elective definitive surgery (high recurrence rate necessitates this):

Resection of the entire sigmoid colon
Can be done laparoscopically or via minilaparotomy (large bowel size negates some laparoscopic benefit)
In very unfit patients: percutaneous endoscopic colostomy (colonoscope-placed drainage tube through abdominal wall into sigmoid to fix bowel in untwisted position)

Emergency surgery (when ischaemia/necrosis present):

Ligate mesenteric vessels before untwisting to theoretically prevent systemic release of ischaemic toxins
Avoid anastomosis in contaminated/ischaemic field
Hartmann's procedure or Paul-Mikulicz double-barrelled stoma preferred

Caecal Volvulus

Patient profile: typically younger and otherwise well (vs. elderly in sigmoid)
Predisposing factors: hypermobile caecum, adhesions, pelvic masses, pregnancy, gastric banding
Endoscopic decompression is often unsuccessful and merely delays treatment
Treatment: Urgent right hemicolectomy is indicated

Volvulus Neonatorum (Midgut Volvulus)

Secondary to intestinal malrotation
Potentially catastrophic - life-threatening emergency
The midgut twists around the superior mesenteric artery
Requires immediate surgical detorsion (Ladd's procedure)

Compound Volvulus (Ileosigmoid Knotting)

Rare
The long pelvic mesocolon allows the ileum to twist around the sigmoid colon
Results in gangrene of one or both segments
Presents with acute intestinal obstruction but comparatively mild distension
Radiograph: distended ileal loops within a distended sigmoid
Treatment: operative decompression, resection, and anastomosis

Volvulus - Summary Box

Feature	Sigmoid Volvulus	Caecal Volvulus	Midgut Volvulus (Neonatal)
Age group	Elderly / African adults	Younger adults	Neonates
Anatomy	Long mesocolon, narrow base	Hypermobile caecum	Malrotation
Key symptom	Massive distension (pain = ischaemia)	Pain + distension	Bilious vomiting, shock
First-line Rx	Endoscopic derotation + flatus tube	Surgery	Emergency Ladd's procedure
Definitive Rx	Sigmoid colectomy	Right hemicolectomy	Ladd's procedure
Emergency Rx (ischaemia)	Hartmann's / Paul-Mikulicz stoma	Right hemicolectomy	Bowel resection if infarcted

Key Radiology Pearls

Sign	Condition	Modality
Target sign / pseudo-kidney sign	Intussusception	USS
Bird's beak	Volvulus (sigmoid/caecal)	Contrast enema
Whirl sign	Volvulus	CT
Coffee bean sign	Sigmoid volvulus	AXR
X-marks-the-spot (two overlapping transition points)	Caecal volvulus	CT

Sources: Bailey & Love's Short Practice of Surgery 28th Ed. | Fischer's Mastery of Surgery 8th Ed. | Grainger & Allison's Diagnostic Radiology | ROSEN's Emergency Medicine | Sleisenger & Fordtran's GI & Liver Disease

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