The Future of Intestinal Failure Surgery. Quo Vadis for a New 'Super Specialty'?

Professor Gordon Carlson, from the Irving National Intestinal Failure Unit at Salford Royal NHS Foundation Trust, discusses the current state of the art for intestinal failure surgery, and where this superspecialty is headed.

• Introduction
• Classification and epidemiology of IF and IF surgery
• Management of abdominal sepsis
• Treatment for intestinal fistula
• Autologous gut reconstruction for short bowel syndrome
• Changes to service delivery
• References

Introduction

Over the last three decades, intestinal failure surgery has begun to emerge as a recognised superspecialty, most closely (if not exclusively) allied to coloproctology. The recent publication, by ESCP, of a consensus document, on the surgical management of intestinal failure in adults [1] provides a timely opportunity to look at where 'IF' surgery has come from and, more importantly, where it is heading. This opinion piece outlines where the state of the art currently lies with regard to surgery for acute severe and chronic intestinal failure and examines future developments which will hopefully facilitate the care of the individual patient with IF and transform and refine specialised services.

Classification and epidemiology of IF and IF surgery

It is difficult to measure something unless one can define it. Attempts to define and classify intestinal failure for the purposes of service design have been hampered for many years by the fact that a considerable amount of acute illness and, in particular, major abdominal surgery, is associated with short term intestinal failure, requiring nutritional support in hospital. Clearly, the ability, for example, to manage post-operative ileus can never be regarded as a highly-specialised field, but a generic issue which all colorectal surgeons should be comfortable with. Attempts have therefore focused on describing and defining those cases of greater complexity which do require specialised management. These considerations led to the classification of intestinal failure into types 1 (acute simple ), 2 ( acute severe) and 3 ( chronic) [2].

Acute severe IF (also known as type 2 IF) is defined as a condition in which artificial nutritional support, usually in the form of parenteral nutrition, is required for a prolonged period for the maintenance of nutritional and/or fluid and electrolyte homoeostasis, under circumstances which are, at least potentially, reversible. . The definition of a 'prolonged period' has really never been formally set out, but attempts to commission a national network in 2008 led NHS England to consider a treatment duration of more than 14 days as a surrogate marker for acute severe IF. [3] Subsequent attempts to make sense of the data obtained from a national survey found this figure to be unworkable, and a duration of treatment of 28 days has since been adopted. Estimates of prevalence based on these numbers suggest that, at any one time, 10 adult patients per million population will have acute severe intestinal failure [3] (i.e. there will be approximately seven thousand adults with acute severe intestinal failure in the EU). These estimates are almost certainly flawed, because it is likely that many patients who should be receiving nutritional support are not doing so, and of course, some patients receive parenteral nutrition but do not require it. What is clear, however, irrespective of the duration chosen, is that it remains extremely difficult to systematically and reliably identify patients with acute severe intestinal failure in the hospitalised population.

It is essential for a growing superspecialty to be able to clearly describe the patients it seeks to treat, and there is an urgent need for coding arrangements to be developed in European Health Systems to identify robustly those patients with type 2 intestinal failure. Only when we are able to do so will we be able also to identify the resources needed to treat them effectively. There is a similarly urgent requirement to develop definitions for specialised intestinal failure surgery. The current absence of a clearly agreed definition causes considerable problems for the establishment of tariffs within health systems, and it also makes it very difficult to audit performance, and to develop specialised training programs.

For the purposes of commissioning IF surgery in England, a working definition has been developed. IF operations are undertaken to restore nutritional autonomy in patients with acute severe or chronic intestinal failure. These may range from a procedure undertaken to close a loop jejunostomy, through laparotomy and takedown of an enterocutaneous fistula, to massive complex resections of entero-atmospheric fistulas and simultaneous complex abdominal wall reconstruction. Specialised surgical procedures undertaken for the management of type 3 IF range from autologous gastrointestinal reconstruction (serial transverse enteric plication or Bianchi), through to small bowel transplantation. Various levels of complexity are clearly evident, but the salient point is the need to describe an operation in which the primary goal is to treat intestinal failure and restore nutritional autonomy, not to reconstruct a complex hernia.

The need to identify these specialised operations, provide specific codes for the activity and establish tariffs for them are under urgent consideration, at least in the English health system. The difficulties and complexities are immense, however, because it will be evident that what defines whether an operation is an 'IF operation' ultimately lies outside the operating theatre. For example, a laparotomy, takedown of a fistula and reconstruction of a complex abdominal wall defect would be regarded as a specialised IF operation if the patient required parenteral nutrition preoperatively and the aim of the surgery was to restore bowel continuity, obviating the need for parenteral nutrition. However, precisely the same technical operation, but perhaps undertaken for fistulation more distally in the small intestine or the colon, in a patient who was therefore not dependent on parenteral nutrition would not be regarded as a specialised IF operation. These are difficult problems for any health system to address, but they need to be solved if specialised recognition and funding is to be established.

Management of abdominal sepsis

We have to accept the fact that surgical complications account for at least 40% of acute severe intestinal failure [4]. Developments in perioperative medicine and surgical technology, combined with an ageing and increasingly comorbid population result in greater number of complex operations being undertaken on increasingly frail and elderly patients. Inevitably, some of these operations will result in complications, and a proportion of these in abdominal surgery will result in acute severe intestinal failure. Abdominal sepsis remains the most important cause of death in these patients and robust measures for prompt identification, aggressive resuscitation, timely and effective antibiotic therapy and prompt surgical source control are of paramount importance. While the surviving sepsis campaign guidance [5] provides an international strategy for the optimum management of sepsis, there has been increasing national interest in incorporating some of these guidelines into protocolised management. It remains to be seen whether the recent incorporation of this guidance, and best available evidence into professional guidelines on the management of anastomotic leakage [6] will hopefully reduce the burden of acute severe IF in the future.

The role of the surgeon remains of great importance for those patients who have a surgically remediable source of abdominal infection, and developments in the management of complex abdominal infection have included improved imaging techniques, more reliable techniques for percutaneous drainage, better decision-making, notably with regard to whether or not to leave the abdomen open, and management of the open abdomen. While there is little doubt that leaving the abdomen open may be a life-saving manoeuvre in severe or persistent abdominal infection, what little high-quality data there is from the only randomised control trial addressing the role of leaving the abdomen open (under circumstances where it could technically be closed), has suggested that doing so may confer no benefit. It seems extremely unlikely that these issues will ever be tested in a large-scale multicentre study, and large cohort studies represent probably the best opportunity to identify which patients require open abdominal management, and to assess the safety and efficacy of techniques such as negative pressure wound therapy, which have gained widespread acceptance in this setting, yet absent the RCT evidence to support their use.

Treatment for intestinal fistula

Management of patients with intestinal fistulas still represents by far the greater proportion of the workload for surgeons treating acute severe intestinal failure. Roughly 75% of all patients with acute severe intestinal failure will have enterocutaneous fistulas. The majority of patients with simple fistulas will not come to specialised centres for treatment and the majority of simple fistulas will heal with conservative treatment alone. Future challenges in the management of patients with intestinal fistulas include development of minimally invasive techniques for fistula therapy and the challenge of simultaneous reconstruction of the gastrointestinal tract and abdominal wall in those patients with extensive entero-atmospheric fistulas.

The use of a collagen plug for minimally invasive fistula closure presents an exciting prospect, as it may allow treatment without the need for complex reconstructive surgery and the associated prolonged hospital stay, morbidity and mortality. The technique is still in its infancy, but successful closure has been reported in the vascular interventional literature [7]. Briefly, a Seldinger technique is used to secure access to the lumen of the bowel at the site of the fistula, following which a collagen plug (similar to, but larger than those used for anal fistulas) is secured across the fistula track, held in place within the lumen of the bowel by a flange (which ultimately separates when the fistula has healed), and a retention disc on the surface of the abdomen.

The outcome of this treatment is still far from certain: treatment has been reported in very small number of patients, and the overall failure rate is approximately 50% [8]. While it appears attractive in principle, and it certainly does not appear to be unsafe, its current place in therapy is unclear. If the anatomy of a fistula is such that it will close spontaneously (for example a lateral fistula in otherwise healthy bowel and in the absence of distal obstruction), then spontaneous closure is likely to occur in any event, and the cost of inserting a fistula plug seems difficult to justify. If the anatomy of the fistula is such that it cannot close spontaneously (for example because of mucocutaneous continuity or distal obstruction), it also seems unlikely that inserting a collagen plug will result in fistula healing. Larger scale trials and analysis of cost effectiveness data would be useful, but seem most unlikely to be forthcoming.

Simultaneous reconstruction of the gastrointestinal tract and abdominal wall continues to present a substantial challenge. While the use of techniques such as separation of components and the systematic involvement of specialist plastic surgeons in intestinal failure reconstruction has certainly been helpful, perhaps the most controversial area, and one in which future clarity needs to be provided, relates to the use of collagen implants. There has been considerable growth in the number and type of collagen implant available, and remarkably aggressive marketing, including claims that some implants can be left safely within the peritoneal cavity during reconstructive surgery. The ideal reconstruction, in which both the abdominal wall and the gastrointestinal tract are returned to their premorbid state, is impossible to achieve, but consideration of abdominal wall reconstruction is of key importance when designing an operation for the patient with an open abdomen and multiple small bowel fistulas.

What is increasingly becoming clear is that the use of collagen implants as a 'bridge' is an almost certain guarantee of (costly) failure [9]. Surgeons undertaking intestinal reconstruction where there is a substantial abdominal wall defect first have to determine whether the patient is sufficiently fit for a considerably extended procedure, in which both the gut and the abdominal wall are reconstructed at the same sitting. This can be a difficult decision, and to undertake both during the same procedure may test the physiological reserve not only of the patient, but of the surgical team. It may well be preferable under some circumstances, to undertake a staged reconstruction, and to close the abdomen with Polyglactin mesh, returning for definitive abdominal wall reconstruction later, when the patient has recovered. Whether a single or a staged operation provides a better outcome, better quality of life and is more or less cost effective has not been evaluated, and represents an important clinical question which could be addressed in a multicentre trial.

If the patient is sufficiently fit for simultaneous gut and abdominal wall reconstruction the optimum method of abdominal wall reconstruction in a contaminated setting still remains to be determined. Despite all the glossy marketing, it is very clear that the use of collagen implants has generally been associated with very disappointing results, with herniation reported in over 50% and a relatively high rate of complications, including recurrent fistulation [10] Polyglactin mesh is likely to give similar results at a fraction of the cost and may have a better safety profile [11]. It remains to be seen whether the most recent surgical option for simultaneous abdominal wall and gastrointestinal reconstruction (Posterior separation of components with transversus abdominis release), provides better long-term results. It is certainly a technically challenging and lengthy procedure to undertake after several hours of prior gut reconstruction, and therefore unlikely to be suitable except for the fittest patients, but early results have been promising [12]. The vast majority of reported studies in all of these settings are cohort observational studies and there is a pressing need to undertake good quality prospective trials to identify which patients are suitable for one stage surgery, which form of abdominal wall reconstruction provides the best results, and, if collagen implants are to be used, which form of collagen implant provides the most durable and safest outcomes.

Autologous gut reconstruction for short bowel syndrome

In contrast to the surgical management of acute severe intestinal failure, surgery has traditionally played a very limited role in the management of patients with established short bowel syndrome on long-term parenteral nutrition (type 3 intestinal failure). The principal role for surgery in such cases has traditionally been to undertake small bowel transplantation for those patients who have eventually lose venous access or who develop irreversible liver disease because of complications of intravenous feeding. There are, however, other surgical options for increasing the available surface area of the small intestine. While spontaneous intestinal adaptation occurs in patients with short bowel syndrome, it is unusual to see nutritional autonomy be spontaneously restored as a result of intestinal adaptation once a patient has been on home parenteral nutrition for two or more years. During this period the small bowel may dilate, increasing its surface area. There is usually no increase in small bowel length however. Work originally undertaken by Adrian Bianchi, a pioneering paediatric surgeon, has established that surgery can further increase the surface area of dilated bowel, by converting some of the increased width to length, thus allowing further dilatation cycles to occur. These techniques are now very firmly established in paediatric surgery, with over 400 publications indicating that intestinal lengthening (also known as autologous gastrointestinal reconstruction) can lead to weaning from parenteral nutrition in more than 50% of suitable individuals.

There is considerably more limited data on the outcome of these techniques when applied to adults with chronic intestinal failure, but what little data there are suggests that similar approaches can be used effectively in selected cases [13]. While the volume of such activity is always like to be low, the cost of home parenteral nutrition is so high and its impact on quality-of-life is so severe that procedure which restore nutritional autonomy to even a modest percentage of patients with type 3 intestinal failure are likely to be justifiable, both ethically and financially. More work needs to be undertaken to identify the optimum method for reconstruction, the optimum timing to undertake this surgery, and the size and characteristics of the patient population most likely to benefit.

Changes to service delivery

The final challenge in the immediate future of the development of intestinal failure as a superspecialty area within colorectal surgery relates to centralisation. There is clearly an uncomfortable balance which needs to be established, such that future colorectal surgeons are able to manage their own anastomotic leaks and otherwise straightforward complications of colorectal surgery, some of which will inevitably result in a period of acute intestinal failure. On the other hand, the complex, resource-intensive medical and nursing management of patients with type 2 intestinal failure and the complex reconstructive surgery associated with its treatment need to be concentrated in a small number of centres in order to obtain the best outcomes for a group of patients in which mortality rates exceeded 60% only 20 years ago, and still exceed 10%.

Health economies wishing to centralise the management of intestinal failure need to find resources with which to do so, and may also face opposition from some hospitals where clinical teams remain opposed to transferring patients to other centres, because of the impression that any reasonably competent colorectal surgeon has the expertise and resources to manage acute severe intestinal failure. The considerable variation in outcomes of treatment, and length of hospital stay in non-specialised centres suggests, however, that this is very far from the truth.

Future developments are likely to be driven by patient expectation, transparency regarding results published in national audits, and interest from regulatory authorities, when clinicians undertake the management of complex clinical problems outwith the expertise required by national and international guidance [1,6,14]. The challenge for the future will be to produce a cohort of adequately trained intestinal failure surgeons, working as part of appropriately resourced multidisciplinary teams, and collaborating in a network of centres which shares best practice and outcome data, and participates in multidisciplinary studies to determine the most clinically effective methods for managing this challenging group of patients

Gordon L. Carlson BSc MD FRCS FRCSEd (Ad Hom)
Professor of Surgery, National Intestinal Failure Centre, Salford Royal NHS Foundation Trust

References

1. ESCP Intestinal Failure Group:, Vaizey CJ, Maeda Y, Barbosa E, Bozzetti F, Calvo J, Irtun Ø, Jeppesen PB, Klek S, Panisic-Sekeljic M, Papaconstantinou I, Pascher A, Panis Y, Wallace WD, Carlson G, Boermeester M. European Society of Coloproctology consensus on the surgical management of intestinal failure in adults. Colorectal Dis. 2016 Jun;18:535-48.
2. Lal S, Teubner A, Shaffer JL. Review article. Intestinal failure. Alimentary pharmacology and therapeutics 2006;24:19-31.
3. National commissioning group. A strategic framework for intestinal failure and home parenteral nutrition services for adults in England. Department of Health 2008.
4. Carlson GL and Dark P. Acute intestinal failure. Curr. Opin. Crit. Care 2010 Aug;16:347-52.
5. Dellinger RP, Levy MM, Rhodes A, Annane D, Gerlach H, Opal SM et al. Surviving Sepsis Campaign. Crit Care Med 2013; 41: 580–637.
6. Association of Coloproctology of Great Britain and Ireland and Association of Surgeons of Great Britain and Ireland. Prevention, diagnosis and management of colorectal anastomotic leakage. ASGBI March 2016.
7. Pidru SM, Yamada K, Morales AF. Enterocutaneous fistula closure with porcine submucosa-derived fistula plug: a novel minimally invasive closure technique. J. Vasc. Interven. Radiol 2013;24:S145-S146.
8. National Institute for Health and Care Excellence. Insertion of a collagen plug to close an abdominal wall enterocutaneous fistula. Interventional procedures guidance IPG 507. Published 2014.
9. Blatnik J, Jin J, Rosen M. Abdominal hernia repair with bridging acellular dermal matrix-an expensive hernia sac. Am.J. Surg 2008;196:147-150.
10. Abdelfatah MM, Rostambeigi N, Podgaetz E, Sarr MG. Long-term outcomes (>5-year follow-up) with porcine acellular dermal matrix (Permacol) in incisional hernias at risk for infection. Hernia. 2015 Feb;19:135-40.
11. Connolly PT, Teubner A, Lees NP, Anderson ID, Scott NA, Carlson GL. Outcome of reconstructive surgery for intestinal fistula in the open abdomen. Ann Surg. 2008 Mar;247:440-4.
12. Fayezizadeh M, Majumder A, Belyansky I, Novitsky YW. Outcomes of Retromuscular Porcine Biologic Mesh Repairs Using Transversus Abdominis Release Reconstruction.J Am Coll Surg. 2016;223:461-8.
13. Yannam GR, Sudan DL, Grant W, Botha J, Langnas A, Thompson JS. Intestinal lengthening in adult patients with short bowel syndrome. J Gastrointest Surg. 2010; 14:1931-6.
14. Association of Surgeons of Great Britain and Ireland. The surgical management of patients with acute intestinal failure. ASGBI 2010.