Abstract :

This article aims to review the technique of ultrasound-guided hydrostatic reduction of childhood intussusception and to illustrate in real-time fashion, the treatment of three cases using this technique. We demonstrate two cases of successful reduction of ileo-colic intussusception. The third case is an example of the complex fronded appearance of ileo-ileo-colic intussusception and failed reduction. This technique is recommended as an alternative method for the treatment of childhood intussusception as it does not involve ionizing radiation, and is a simple and safe procedure.

Introduction :

The hydrostatic reduction of childhood intussusception using ultrasound guidance is a well-recognized alternative method for the reduction of childhood intussusception, the other non-operative methods being reduction with barium or air using fluoroscopic guidance. Its main advantage is the avoidance of ionizing radiation, which is especially important in children. As ultrasound is often the first line imaging modality for the diagnosis of intussusception, the procedure can be performed wholly within the ultrasound room after the diagnosis is made. This is efficient and saves time. The results of hydrostatic reduction of childhood intussusception using tap water, saline and Ringer's solution has been described by various authors (1-6). To date, we have performed hydrostatic reduction using Hartmann's solution in 64 episodes of intussusception occurring in 58 children from March 1994 to July 1999. In our previously published data, we reported the success rates of 92.9% for ileo-colic intussusception 10% for ileo-ileo-colic intussusception, with an overall success rate of 71.1%. The mean reduction time for the successful cases of ileo-colic intussusception was 12.6min (7). In addition, we found that during ultrasound, when the mass is surrounded by fluid in the cecum, the ileo-colic type of intussusception could be differentiated from the ileo-ileo-colic type (8). A typical complex fronded appearance is seen in the ileo-ileo-colic type of intussusception as compared to a simple mass in the ileo-colic type (8). This article aims to review the technique of ultrasound-guided hydrostatic reduction of childhood intussusception and to demonstrate real-time this technique.

Technique :

All children with suspected intussusception are assessed by the pediatric surgeon prior to arrival at the ultrasound suite. If the ultrasound scan is positive for intussusception, informed consent is obtained for hydrostatic reduction. An intravenous line is set up, blood samples taken for electrolytes and cross-matching, and the child is sedated with intravenous dormicum (0.2mg/kg dose). Blood pressure and pulse rate are monitored before and during the procedure. The pediatric surgeon is present in the ultrasound suite throughout the procedure and the operating theatre notified in case emergency surgery is required. The child is placed on an inflatable plastic enema ring (Fig. 1) within which is placed a suction device enabling continuous suction of fluid from the enema ring. A Foley's catheter of the largest appropriate size (10- to 18- French) is inserted into the rectum and the balloon is gently inflated (Fig.2). Hartmann's solution, warmed to body temperature, is slowly hand injected into the Foley's catheter using a 50-ml syringe. A consistent force of injection is maintained and hydrostatic pressure kept to within 100mmHg by checking the pressure gauge attached to the Foley's catheter via a three-way tap. During reduction, the intussuceptum is observed under continuous ultrasound-guidance (Fig.3) as it proceeds to the cecum and reduces across the ileo-cecal valve (9). The criteria for successful reduction are disappearance of the intussusceptum through the ileo-cecal valve followed by passage of water and air bubbles from the cecum into the terminal ileum. The peritoneal cavity is also scanned intermittently for the presence of a sudden increase and sudden simultaneous loss of fluid from the bowel indicating perforation. For intussusceptums that fail to progress, the possibility of ileo-ileo-colic intussusception should be considered. This type of intussusceptum, when surrounded by fluid in the cecum, has a complex fronded appearance. In these patients, we adopt a less aggressive approach as the reduction success rate is small and surgical management is usually required (8). In all other cases, the procedure would be attempted up to a maximum of three times after which it would be terminated. After successful reduction, the terminal ileum is scanned for the presence of a lead-point or residual mass.

Fig.1 The plastic enema ring is shown together with the Foley's catheter, which is connected by plastic tubings and a three-way tap to a pressure gauge and a 50-ml syringe. Fig.2 The child is placed in the plastic enema ring and an 18-French size Foley's catheter is inserted into the rectum. Fig.3 Continuous ultrasound-guidance is provided during hydrostatic reduction. During the procedure, the child's buttocks are held together to form a tight seal to reduce leakage of fluid.

Demonstration :

This ultrasound demonstration comprises three examples. The first example is a case of successful reduction of an ileo-colic intussusception, demonstrating reduction of the intussusceptum from the mid-transverse colon to the terminal ileum. The second example is another case of successful reduction of ileo-colic intussusception demonstrating the reduction of the intussusceptum from the cecum across the ileo-cecal valve. The third case is an example of the complex fronded appearance of ileo-ileo-colic intussusception with non-progression at the cecum and eventual failed reduction.

---

Example 1 :

History:

A 12-month-old boy was noticed to be irritable for about eight hours before admission. He subsequently also developed bloody diarrhea and vomiting. He had no significant past medical or surgical history. On examination, he was afebrile and no abdominal mass was palpable. Supine abdominal radiographs were non-specific. There was no soft tissue mass or dilated bowel loops. The clinical diagnosis of intussusception was made. This was confirmed by ultrasound scans, which demonstrated the typical "doughnut" and "pseudokidney" signs of intussusception. The intussusception was located at the mid-transverse colon.

Ultrasound demonstration:

Hartmann's solution, instilled intra-rectally surrounds the leading edge of the intussusceptum at the mid-transverse colon. The reducing intussusceptum is monitored under ultrasound guidance and is progressively reduced to the cecum. In the cecum, the mass has a simple ovoid appearance typical of ileo-colic intussusception. The intussusceptum slowly reduces in size as Hartmann's solution is continuously instilled. Finally, it successfully reduces across the ileo-cecal valve. The ileo-cecal valve is edematous. Free fluid and bubbles are easily visualized as they cross the ileo-cecal valve. No residual mass is detected in the terminal ileum.

---

Example 2 :

History:

A 12-month old previously healthy girl presented with the classical clinical triad of abdominal pain, blood in stools and a palpable abdominal mass. The duration of her symptoms was about two days. She did not have vomiting or fever. Abdominal radiographs were normal with no soft tissue mass detected. Ultrasound scan showed the typical features of intussusception.

Ultrasound demonstration:

The intussusceptum has already been reduced hydrostatically to the cecum from its original location in the hepatic flexure. A simple ovoid mass is seen in the fluid-filled cecum, confirming the diagnosis of ileo-colic intussusception. This mass is demonstrated being reduced from the cecum across the ileo-cecal valve into the terminal ileum. No filling defect or lead point is detected in the fluid-filled terminal ileum.

---

Example 3 :

History:

A six-month-old boy presented with intermittent crying for eight hours and was suspected to have colicky abdominal pain. He had no history of diarrhea, bloody stools or vomiting. On examination, a mass was palpated at the epigastrium. His abdomen was otherwise soft and non-tender. Supine abdominal radiographs were unremarkable. Ultrasound scan showed typical features of intussusception.

Ultrasound demonstration:

The intussusceptum has already been reduced hydrostatically from its original location in the splenic flexure to the cecum. The mass has a complex fronded appearance in the fluid-filled cecum. This finding is highly suggestive of the ileo-ileo-colic type of intussusception. The intussusceptum failed to progress after a 20- minute attempt at hydrostatic reduction. This patient was referred for surgery. At surgery, a tight ileo-ileo-colic intussusception was confirmed. Manual reduction was difficult resulting in serosal tears requiring bowel resection. The patient was well on discharge and subsequent follow-up.

Conclusion :

The technique of ultrasound-guided hydrostatic reduction of childhood intussusception is reviewed and is supplemented by a real-time demonstration of this technique in three cases. The demonstration shows the clarity with which the intussusception and the hydrostatic reduction process can be visualized with ultrasound. As a bonus, the ileo-colic and ileo-ileo-colic types of intussusception can be differentiated in the fluid-filled cecum, with management implications. We would therefore recommend this technique as an alternative method for the treatment of childhood intussusception.

References :

1.	Wang G, Liu S. Enema reduction of intussusception by hydrostatic pressure under ultrasound guidance: a report of 377 cases. J Pediatr Surg 1998; 23:814-818
2.	Woo SK, Kim JS, Suh SJ, Paik TW, Choi SO. Childhood intussusception: US-guided hydrostatic reduction. Radiology 1992;182:77-80
3.	Riebel TW, Nasir R, Weber K. US-guided hydrostatic reduction of intussusception in children. Radiology 1993; 188:513-516
4.	Choi SO, Park WH, Woo SK. Ultrasound-guided water enema: an alternative method of nonoperative treatment for childhood intussusception. J Pediatr Surg 1994;29:498-516
5.	Rohrschneider WK, Troger J. Hydrostatic reduction of intussusception under US guidance. Pediatr Radiol 1995;25:530-4
6.	Gonzalez-Spinola J, Del Pozo G, Tejedor D, Blanco A. Intussusception: the accuracy of ultrasound-guided saline enema and the usefulness of a delayed attempt at reduction. J Pediatr Surg 1999; 34: 1016-20
7.	Peh WCG, Khong PL, Chan KL et al. Sonographically guided hydrostatic reduction of childhood intussusception using Hartmann's solution. AJR 1996;167:1237-1241
8.	Peh WCG, Khong PL, Lam C et al. Ileoileocolic intussusception in children: diagnosis and significance. Br J Radiol 1997;70:891-896
9.	Peh WCG, Khong PL, Lam C et al. Reduction of intussusception in children using sonographic guidance. AJR 1999; 173(4): 985-8

---