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Autologous Bowel Reconstruction for Short Bowel Syndrome in Children
Antonino Morabito, MD, FRCS (Ed), FRCS (Eng.), FICS
Paediatric Autologous Bowel Reconstruction and Rehabilitation Unit, Manchester, UK
This article is based on a presentation given at the annual Oley Consumer/Clinician Conference held in June 2013 in Cape Cod. You can view the slides from the presentation (click here) or watch a recording of the presentation on DVD; call Oley at (800) 776-6539 or click here to borrow a DVD.
Short bowel syndrome (SBS) is a multisystem disorder caused by malabsorption of nutrients as a result of inadequate intestinal length. It may be the result of congenital and functional disorders that impair the absorptive capability of the small intestine, or the result of surgical resection. It may lead to diarrhea, fluid and electrolyte imbalance, and eventually, failure to thrive.
Following intestinal resection, the residual (or remaining) bowel adapts structurally and functionally in ways that partially make up for the loss of surface area, especially in children. The small intestine rapidly increases in length between gestation weeks 30 and 40, and in the first eighteen months of life. This makes adaptation following resection more likely when a child is very young.
Structural changes that have been documented include dilatation and elongation of the proximal bowel wall with mucosal hypertrophy; hyperplasia and increased crypt depth; and increased brush border enzyme activity. [Editor’s note: Dilatation means the intestine expands in circumference, while elongation means it increases in length. “Mucosal hypertrophy” refers to an increase in the folds of the intestinal lining (or mucosa), and “hyperplasia” is an increase in the number of cells. “Increased crypt depth” represents increased mucosal cell production, and an increase in “brush border enzyme activity” means increased digestive capacity.] Taken together, these changes help increase the absorptive capability of the remaining small intestine and contribute to a patient’s ability to tolerate and maintain their nutritional status with oral and/or enteral (or tube) feeding.
In addition to age, several factors predict the likelihood of whether a patient will be able to sustain him- or herself with enteral and/or oral feeding. These include whether the patient has an ileocecal valve (ICV) and colon; the length and condition of the remaining bowel; the type of anastomosis; and whether there is bacterial overgrowth present.
The presence of the ICV seems to affect how much residual intestine is required before the symptoms of SBS emerge. In one study of neonates, a residual small bowel length of at least 40 cm was required to be compatible with life when there was no ICV. When there was an ICV, however, a residual length of as little as 10 cm has been suggested as a lower limit. These factors are important but not essential for identifying which patients are at risk of lifelong parenteral nutrition (PN) dependence and who may benefit most from surgical intervention.
The starting point for all patients after an extensive small bowel resection is parenteral nutrition. Once the plan to begin PN is discussed and agreed upon with the parents and/or the caregivers, a minimal surgical intervention is required to insert a central venous catheter for the administration of PN.
Due to the potential severity of complications associated with PN, it should be viewed as a temporary therapy plan, and oral feeding or enteral nutrition (EN, or tube feeding) should be introduced as early as possible in order to stimulate the swallowing mechanism, bowel adaptation, and entero-hepatic circulation [the circulation of substances such as bile salts from the liver to the small intestine, into the bloodstream, and back to the liver].
Our intestinal rehabilitation program also emphasizes, among other things, vein preservation and liver-sparing PN. To preserve veins, we use the smallest catheter possible, and use urokinase and/or 70% alcohol lock to avoid catheter blockages and infection. We treat central-line infections promptly; if an infection cannot be resolved, the catheter is removed.
Briefly, the liver-sparing PN regimen involves minimizing the amount of IV fat given to the patient, taking into account how much they receive via enteral feeds. [For more details, see “Intestinal Rehabilitation and Bowel Reconstructive Surgery: Improved Outcomes in Children with Short Bowel Syndrome,” Khalil et al, JPGN 2012;54:505-509.]
Advanced surgical techniques have allowed the development of the concept of autologous gastro-intestinal reconstruction (AGIR). [In autologous reconstruction, only the patient’s own intestine is used.] It is a relatively new concept with well recognized indications, i.e. severe SBS, intestinal dilatation, failure to progress to enteral or oral autonomy, or bacterial overgrowth when 100 percent PN dependent. The aim of AGIR is to encourage the natural processes of adaptation and dilatation in order to use the increased circumferential tissue to enhance the residual bowel. AGIR is a combination of procedures.
My own approach to the patient with intestinal failure is to look at the etiology [or cause] of SBS, residual bowel length, motility, and enteral tolerance, and then create an individualized program. I do not commit to one type of surgery prior to operation as I frequently combine techniques, trying to tailor the operation to the patient’s needs. Innovative surgery plays an important role in my approach.
In assessing the patient for AGIR, I perform an upper GI series or an entero CT to study the bowel anatomy and physiology. An assessment for bacterial overgrowth is also essential.
Stable liver function is important. It is also important to note that autologous bowel reconstruction improves liver function. Liver cirrhosis is a contraindication to AGIR.
For AGIR, the formation of two stomas (tube proximal and distal) is necessary if the child’s bowel is not already dilated. These stomas will allow controlled bowel expansion, which in turn will allow a surgeon to perform AGIR. Controlled tissue expansion is achieved by feeding the patient and clamping the proximal tube stoma for a progressively longer time period each day (increased by five-minute increments). The effluent is then re-fed into the distal tube stoma. Some patients dilate their bowel naturally over a period of time (sometimes years). The controlled tissue expansion speeds this process, so it takes only twenty to twenty-four weeks to maximize bowel diameter.
My choice of the surgical technique(s) to be used in AGIR is based on the length of remaining bowel and the likelihood for the patient to achieve oral or enteral autonomy with one or more operations. In the presence of severe short bowel (5 to 20 cm), one operation might not be enough to give patients enteral autonomy. In our experience, the longitudinal intestinal lengthening and tapering procedure (LILT) works very well in this situation. The LILT procedure doubles (100 percent) the length of the remaining bowel and allows the possibility of more surgery to further slow the transit time if the patient fails to achieve enteral autonomy.
Single or multiple antiperistaltic (reversed) segments of intestine can be added to further delay transit, increase mucosal contact time, and enhance bowel adaptation and absorption. Additional bowel length (68 percent) can be achieved through a STEP procedure (serial transverse enteroplasty). [The STEP procedure involves creating a series of longitudinal staple lines in a dilated loop of bowel; the result is a series of “baffle valves” that may slow transit and increase the bowel’s absorptive capacity. (from Kishore Iyer, LifelineLetter, May/June 2007).] Still further improvements in transit time can be obtained by longitudinal colonic lengthening with or without a sigmoid J-pouch and colonic interposition.
In patients with more than 30 cm of residual bowel, the choice of which procedure to perform should be based on the surgeons’ experience. In these circumstances and in the context of a structured plan to intestinal rehabilitation, one operation should be sufficient to achieve enteral autonomy. The real problem in these patients is related to dysfunctional and dilated bowel and the STEP procedure works well for these patients. Once these issues have been resolved, the patient should successfully progress to enteral autonomy. We think that surgeons should be able to offer all the available techniques and choose from them to their patients’ benefit.
Of the twenty-seven children with SBS treated at our intestinal failure center between 2000 and 2009, twenty-five have survived (92%). Excluding the two patients who died and two for whom we have no PN data, 21 (91%) are now off of PN. Nineteen of these children required bowel lengthening procedures, and eight had simple bowel reconstruction.
Today, a normal life of good quality, of a normal time span, has become a real and achievable expectation for patients with short bowel.
References are available at www.oley.org or by calling (800) 776-6539. For information on bowel reconstruction in adults, please see “Restoring GI Autonomy to Intestinal Failure Patients,” Kishore Iyer, MBBS. FRCS, FACS, LifelineLetter, May/June 2007.