Explain malrotation and intestinal obstructions in surgery

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intestinal malrotation AND obstruction

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intestinal malrotation volvulus diagnosis management pediatric surgery guideline

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upper gastrointestinal contrast study intestinal malrotation midgut volvulus corkscrew duodenum

Two-panel diagnostic image featuring an upper gastrointestinal (GI) contrast study (fluoroscopy/radiography) demonstrating classic signs of midgut volvulus secondary to intestinal malrotation. Panel (a) illustrates the 'corkscrew sign,' characterized by the spiral or helical twisting of the distal duodenum and proximal jejunum around the superior mesenteric artery axis. Panel (b) reveals an incomplete duodenal obstruction with marked dilation of the first and second portions of the duodenum. A tapered, 'beak-like' appearance is visible at the point of obstruction where the bowel twists. The contrast study identifies the abnormal right-sided position of the duodenojejunal flexure, rather than the normal position to the left of the spinal column. These radiographic findings are critical for diagnosing pediatric surgical emergencies such as midgut volvulus, where torsion of the narrow mesenteric base leads to intestinal ischemia and high-grade obstruction.

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https://pmc.ncbi.nlm.nih.gov/articles/PMC11271324/

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Intestinal malrotation

Intestinal malrotation is a congenital failure of normal fixation of the midgut. Normally, the bowel returns to the abdomen and becomes fixed with a broad mesenteric base. In malrotation, the duodenojejunal junction and caecum lie abnormally close, leaving the midgut suspended on a narrow mesenteric pedicle around the superior mesenteric artery (SMA).

This narrow base predisposes to twisting of the bowel, called midgut volvulus, causing acute obstruction, vascular compromise, intestinal gangrene, short-bowel syndrome, or death.

Embryological basis

Classically, normal midgut development involves:

Physiological herniation of midgut
Approximately 270° counterclockwise rotation around the SMA
Return to abdomen and fixation

Failure of fixation results in:

Right-sided small bowel
Abnormally placed, often medial caecum
Narrow mesenteric root
Ladd bands: abnormal peritoneal bands extending from the malpositioned caecum across the duodenum to the right lateral abdominal wall. These can compress the duodenum and cause obstruction.

Sabiston Textbook of Surgery, p. 2683-2684.

Clinical presentation

About 90% of symptomatic cases present before 1 year of age, but malrotation may present in older children or adults.

Acute midgut volvulus

Sudden bilious vomiting, especially in a neonate
Colicky abdominal pain
Lethargy, shock, hematochezia or melena in advanced ischemia
Distension may be absent initially and is a late ominous finding
Metabolic acidosis suggests bowel ischemia

Chronic or intermittent presentation

Recurrent bilious or non-bilious vomiting
Intermittent crampy pain
Poor feeding, failure to thrive
Early satiety, malabsorption, protein-losing enteropathy
Symptoms may mimic reflux or functional abdominal pain

Bilious vomiting in a newborn should be assumed to be intestinal obstruction, including malrotation with volvulus, until proved otherwise.

Diagnosis

Plain abdominal radiograph
- May be normal, show proximal obstruction, or a gasless abdomen
- It is nonspecific and must not delay surgery if volvulus is strongly suspected.
Upper GI contrast series
- Best confirmatory study in a stable child
- Findings:
  - Duodenum fails to cross the midline
  - Duodenojejunal junction lies abnormally to the right
  - “Corkscrew” appearance of twisted proximal jejunum or duodenum in volvulus
  - Tapered “bird-beak” obstruction in the third part of duodenum
Ultrasound with Doppler
- Abnormal SMA-SMV relationship
- SMV may lie left of or anterior to SMA
- “Whirlpool sign” indicates twisting of mesentery and vessels

Upper GI contrast study showing corkscrew appearance in midgut volvulus due to malrotation

Management

Suspected midgut volvulus is an emergency. Do not delay operative treatment in an unstable child for contrast imaging.

Initial management:

Nil by mouth
Nasogastric decompression
IV fluids and correction of electrolyte and acid-base abnormalities
Broad-spectrum antibiotics if ischemia, perforation, or sepsis is suspected
Urgent paediatric surgical referral

Ladd procedure

The definitive operation includes:

Counterclockwise detorsion of volvulus, if present
Division of Ladd bands compressing the duodenum
Broadening of the narrow mesenteric base
Placement of small bowel on the right and colon on the left
Appendicectomy, because the appendix will remain in an atypical position and could confuse later diagnosis
Resection of nonviable bowel, if necessary

A questionable bowel segment may be preserved and reassessed at planned second-look laparotomy after 24-36 hours. A recent clinical series also describes the Ladd procedure as standard treatment, with emergency surgery for volvulus and resection when necrosis is present (2024 clinical review).
Sabiston Textbook of Surgery, p. 2684.

Intestinal obstruction

Intestinal obstruction is failure of normal onward passage of intestinal contents due to either a mechanical block or failure of intestinal motility.

Classification

1. By mechanism

Type	Meaning	Examples
Mechanical obstruction	Physical blockage of the lumen or extrinsic compression	Adhesions, obstructed hernia, tumour, volvulus, intussusception, stricture
Dynamic obstruction	Failure of propulsion without a mechanical block	Paralytic ileus, acute colonic pseudo-obstruction, electrolyte disturbances

2. By level

Small-bowel obstruction (SBO): high or low
Large-bowel obstruction (LBO)

3. By severity

Partial or incomplete
Complete

4. By vascular status

Simple obstruction: blood supply intact
Strangulating obstruction: venous then arterial compromise
Closed-loop obstruction: bowel occluded at two points, high risk of rapid strangulation and perforation

Causes

Small-bowel obstruction in adults

Common causes:

Postoperative adhesions: most common
Incarcerated or strangulated hernia
Crohn disease stricture
Small-bowel tumour
Intussusception
Gallstone ileus
Volvulus
Foreign body or bezoar

Large-bowel obstruction

Common causes:

Colorectal carcinoma
Volvulus, especially sigmoid volvulus
Diverticular stricture
Faecal impaction
Inflammatory stricture

Neonatal intestinal obstruction

Important causes include:

Malrotation with midgut volvulus
Duodenal atresia, web, or stenosis
Jejunoileal atresia
Meconium ileus
Hirschsprung disease
Anorectal malformation
Necrotizing enterocolitis

Clinical features

The classical quartet is:

Colicky abdominal pain
Vomiting
Abdominal distension
Absolute constipation, meaning no stool or flatus

Bailey & Love’s Short Practice of Surgery, p. 1402.

Clinical pattern by site

Feature	High small bowel	Low small bowel	Large bowel
Vomiting	Early, profuse	Later	Late, may become faeculent
Distension	Minimal	Central and marked	Early and pronounced
Pain	Colicky, central	Colicky, central	Less severe initially, lower abdominal
Dehydration	Early and severe	Moderate	Late
X-ray	Few proximal dilated loops	Multiple central small-bowel loops	Peripheral colonic dilatation

Bailey & Love’s Short Practice of Surgery, p. 1402.

Features suggesting strangulation or ischemia

These require urgent surgery:

Continuous severe pain, rather than intermittent colic
Tachycardia, fever, hypotension
Localized tenderness, guarding, rigidity, rebound tenderness
Leukocytosis, rising lactate, metabolic acidosis
Bloody nasogastric aspirate or rectal bleeding
CT evidence of closed-loop obstruction, pneumatosis, portal venous gas, reduced bowel-wall enhancement, or free fluid

Investigations

Initial tests

FBC, CRP
Urea, creatinine, electrolytes
Serum lactate and arterial/venous blood gas if ischemia suspected
Group and save or crossmatch if surgery likely

Imaging

Abdominal radiograph
- Useful initial test
- Small bowel: central dilated loops, valvulae conniventes
- Large bowel: peripheral dilated colon with haustral markings
- May show free gas if perforation
CT abdomen and pelvis with IV contrast
- Preferred imaging in most stable adults
- Identifies level, cause, closed loop, ischemia, perforation, and complications.
Water-soluble contrast study
- Sometimes used in adhesive SBO
- Can help predict resolution and may have therapeutic value in selected uncomplicated cases.
Contrast enema
- Used selectively for colonic obstruction, volvulus, or neonatal distal obstruction.

Management principles

Immediate measures for all suspected obstructions

Admit and assess severity
Nil by mouth
Two wide-bore IV cannulas
IV crystalloid resuscitation
Correct potassium and other electrolyte abnormalities
Nasogastric tube for vomiting or significant distension
Urinary catheter and monitor urine output
Analgesia and antiemetics
Broad-spectrum antibiotics if strangulation, perforation, sepsis, or operation is likely
Early surgical assessment

The core treatment framework is nasogastric drainage, fluid and electrolyte replacement, and relief of the obstruction. Bailey & Love’s Short Practice of Surgery, p. 1407.

When conservative treatment may be appropriate

A carefully observed nonoperative approach can be used in selected patients with:

Suspected uncomplicated adhesive partial SBO
No peritonitis
No ischemia or strangulation
No closed-loop obstruction
Stable vital signs and improving clinical status

Indications for urgent operation

Peritonitis or perforation
Suspected strangulation or bowel ischemia
Closed-loop obstruction
Obstructed or strangulated hernia
Volvulus with ischemia
Complete obstruction with deterioration
Failure of nonoperative management
Malrotation with suspected midgut volvulus

Operative goals

Identify and relieve the obstruction
Divide adhesions, reduce hernia, untwist volvulus, resect tumour, or remove obstructing lesion as appropriate
Assess bowel viability
Resect nonviable bowel
Restore continuity or form a stoma when required

Exam-focused comparison: malrotation versus general obstruction

Point	Malrotation with volvulus	General adult intestinal obstruction
Usual age	Neonates and infants, but any age possible	Usually adults
Main danger	Rapid total midgut ischemia	Strangulation, perforation, sepsis
Key symptom	Bilious vomiting	Pain, vomiting, distension, constipation
Best diagnostic test if stable	Upper GI contrast series	CT abdomen with IV contrast
Definitive surgery	Ladd procedure	Cause-specific operation
Surgical urgency	Immediate if volvulus suspected	Immediate if strangulation, closed loop, or perforation suspected

Key takeaway: In a neonate with bilious vomiting, always exclude malrotation with midgut volvulus first because delay can cause catastrophic loss of bowel.

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