Conversion of J-Pouch to Kock Pouch

ABBREVIATIONS

CD

Crohn’s disease

ES

extrasphincteric

IPAA

ileal pouch-anal anastomosis

IS

intersphincteric

QoL

quality of life

SBS

short bowel syndrome

SP

sphincter preserving

INTRODUCTION

Continent ileostomy (or Kock pouch) can be defined as a surgical procedure that constructs a continent bowel reservoir to plan intermittent evacuation. It was first reported by Nils G. Kock in 1969 and served as an option for patients with ulcerative colitis or familial adenomatous polyposis when they were referred to a total proctocolectomy and permanent end ileostomy previously. Kock pouch was initially developed with the idea to facilitate a pouch to reserve feces and then was supplemented with a valve mechanism, which had the advantages of eliminating an external appliance and promoting body image, therefore improving quality of life (QoL). Most studies regarding the Kock pouch suggested a greater satisfaction among patients than those receiving end ileostomy. However, some morbidities were observed in both short-term and long-term periods after the operation and such patients might require reoperation. ^, Early complications, such as leakage from suture lines, necrosis of the intussuscepted valve, and hemorrhage from the various suture lines, were reported to be rare. Although some early complications were severe, pouches were able to be rescued in most cases. By contrast, late complications were difficult to be eradicated and some patients may need more than one revision. Prolapse, fistulas, and valve slippage were common late complications, while particularly valve slippage was one of the main reasons for reoperation and pouch failure.

Ileal pouch-anal anastomosis (IPAA), with J-pouch being the most performed configuration, substitutes the Kock pouch later, which has a lower ratio of revisions and is less technically challenging. Nowadays, Kock pouch is only performed in rare conditions even in the specialized colorectal units. The long-term outcomes of J-pouch remain unsettled, with a failure rate of J-pouch being reported to be 6% to 16%. Complications seemed to develop as time went by and many patients suffered worse functional outcomes. The most common complication following operation was pelvic sepsis which was reported to be associated with a high risk for pouch failure. Other reported complications included but were not limited to Crohn’s disease (CD) of the pouch, pouchitis, structural or functional failure, neoplasia, perianal disease, pouch vaginal fistulas, and so on. In addition, some patients may be confronted with worsened sphincter mechanism and feces incontinence. In these circumstances, pouch salvage procedures could be adopted and might be successful in some patients; however, others suffered from definitive pouch failure.

In most institutions, two major procedures offered to patients with a failed J-pouch except for pouch reconstruction, including pouch excision combined with construction of end ileostomy or leaving pouch in situ for indefinite diversion by an end loop ileostomy. Each strategy has its advantages and disadvantages. Pouch excision was reported to have the same postoperative morbidity as indefinite diversion with pouch in situ but pouch excision had improved QoL. However, other surgeons argued that pouch excision was related to a worse prognosis. Delayed healing of perineal wounds, sepsis, and persistent perineal sinus were common complications in patients who received pouch excision. Other nagging issues such as increasing ileostomy output, skin irritation, and leakage were not rare as well. When comparing the morbidity of pouch excision to indefinite diversion, it was found that pouch excision was accompanied by a higher morbidity procedure. Regardless of which strategy to be applied, considerable lengths of distal ileum will be unavoidably removed. In contrast, if dissecting a failed pouch and reconstructing a new J-pouch is employed, about 30 to 60 cm of ileum will be used. This should be taken into consideration since these patients are at risk of malabsorption, which may lead to water and electrolyte disturbances and other metabolic disturbances including bile acid malabsorption, steatorrhea, and deficiency of vitamin. While the long-term prognosis of malabsorption was indefinite, these patients should be meticulously consented before surgery.

Given the shortcomings of pouch excision or infinitive diversion, an alternative is a transposition of the pelvic pouch and conversion to a Kock pouch. Several studies have assessed the outcomes of patients with conversion of J-pouch to Kock pouch; however, the quality of these studies was limited by the relatively small number of enrolled patients ( Table 32.1 ). In general, the ratio of Kock pouch retention after conversion was shown to be from 81.82% to 95.31%, while the revision ratio was observed to range from 36.36% to 61.54% after a median follow-up of 5 years. ^, Patients from 31–36% of patients with a Kock pouch suffered from early postoperative complications, including postoperative hemorrhage, wound infection, or ileus or pelvic abscess but no mortality was reported. ^, Pouch incontinence and valve slippage were the most commonly reported late complications that resulted in difficulties in intubation. As to the causes of pouch failure, fistulas such as pouch–cutaneous fistula, enterocutaneous or enteroenteric fistula, or CD-related fistula was the leading contributors, with others being parastomal or abdominopelvic abscess, valve slippage, and pouch dysfunction. The QoL of patients with Kock pouches appears to be better than that in those who received a conventional ileostomy. The rates of complications were not significantly different between patients whose Kock pouches were converted from a previous J-pouch and those who received a primary Kock pouch construction. Moreover, it has been reported that the pouch revision rate was similar when a J-pouch was converted to a Kock pouch regardless of whether the original pouch was used or excised during the reconstruction procedure.

Table 32.1

Outcomes of Patients With Conversion of J-Pouch to Kock Pouch (Only Studies With More Than 10 Patients were Included)

Studies	Enrolled Patients (n)	Median Follow-Up Time (year)	Ratio of Pouch Retention (%)	Revision Rate (%)	Preservation of the Pelvic Pouch n (%)
Börjesson et al.	13	6	84.62	62.53	12(92.31)
Wasmuth et al.	11	7	81.82	36.36	7(63.64)
Lian et al.	64	5	95.31	45.30	16(25.00)
Aytac et al.	81	5	83.95	Major: 49 Minor: 19	–

Conversion of failed J-pouch to Kock pouch is technically feasible and should be regarded as an alternative, especially for patients who have a high motivation to keep fecal continence. However, this procedure is well-tried, complex, and challenging which requires extensive expertise. In this chapter, we elaborated on the indications, contraindications, technique details, and precautions of conversion of J-pouch to Kock pouch.

PRINCIPLES

To begin with, the Kock pouch can be referred to by patients either as a primary procedure after receiving a restorative proctocolectomy, or as a salvage strategy for failed pelvic pouch. The indications and contraindications of the latter situation are the points of interest in this chapter.

Indications

In general, patients who have unsatisfactory pouch function or suffer from complications of J-pouch which worsen QoL or even lead to pouch failure can be referred to Kock pouch. Since the J-pouch is the most commonly constructed pelvic pouch, we use the term “J-pouch” in the text, which is not meant to exclude the S-pouch.

Complications of J-Pouch : Septic complications, including pelvic sepsis, perianal abscess, and pouch fistula, accounted for most of the primary reasons for pelvic pouch failure in the majority of the studies. Many patients would undergo several operations to correct the complications before they were referred to Kock pouch. Other complications of J-pouch leading to Kock pouch construction consist of incontinence, pouchitis, stricture, poor pouch function, persistent anal pain, recurrent small-bowel obstruction, dysplasia, and irritable pouch syndrome.

Shortened Small Bowel or Mesentery : During the construction of the primary J-pouch, considerable lengths of distal ileum have been used in the formation of the pouch followed by being pulled down to the pelvic floor to reach the anus. The length of the ileum and/or mesentery in the physical condition is enough in most cases. However, once pouch failure is definite and reconstruction is inevitable, the profile of the ileum and mesentery should be carefully appraised. It should be taken into account that such patients are prone to short bowel syndrome (SBS), putting patients at risk of malabsorption. SBS could also occur in those who received pouch excision or indefinite diversion. Given that the conversion of the J-pouch to a Kock pouch with the original pouch preserved can help retain plenty of ileum, patients with shortened small bowel or mesentery can be referred to the Kock pouch.

Unsuitable Anatomy of Pelvis : The physical and/or pathological conditions of the pelvis should be assessed before the pelvic pouch is constructed. A narrow pelvis or an irradiated pelvic floor with inflammation or fibrosis, can sometimes prevent the patients from constructing J-pouch. Since a re-do J-pouch in the pelvis is difficult in these circumstances, lifting the pouch to the abdomen for conversion to the Kock pouch can be under consideration.

Crohn’s Disease in Selected Patients : The lesions of CD are possible to occur in any section of the whole alimentary tract, with the pouch not being able to be exempted. Several studies indicated that CD was a risk factor associated with pouch failure regardless of the pouch configuration as a Kock pouch or J-pouch. However, it was reported that the outcomes of the J-pouch in selected patients with CD were inspiring, which indicated that the pouch could be maintained in function in 55% to 90% of the patients in the long run. ^, Selected CD patients with a failed J-pouch with small bowel not being involved can also be considered for Kock pouch construction. However, it is of note that such patients should fully consent to complications and particularly possible CD lesions in the Kock pouch.

Poor Sphincter Function : Sphincter damage may arise from J-pouch construction or other diseases. The pressure of the anal sphincter in patients with J-pouch is lower than that in those who have not undergone any pelvic surgery. The damage to the sphincter may result from anal dilation, manipulation, or mucosectomy. It was reported that poor sphincter function was associated with poor postoperative functional outcomes for patients with J-pouch. Furthermore, there are two patient populations who are susceptible to poor sphincter strength: elderly patients and females with a history of obstetric complications. A digital rectal examination can help discriminate candidates with well-functioning anal sphincters for J-pouch and patients with dysfunctional anal sphincter who are suitable for conversion.

These abovementioned indications can help surgeons decide about whether to adopt the conversion of J-pouch to Kock pouch or not. However, when it comes to the decision of selecting surgical procedures as to whether the original pouch should be preserved for Kock pouch construction or not, further detailed elucidation is required. Although both of these procedures could be selected for most eligible patients, one procedure can be preferred to another in specific clinical scenarios.

Indications for Preserving the Original Pouch : The compelling indication of conversion of a failed J-pouch to a Kock pouch with the original pouch being preserved is the potential risk of SBS in these patients. For such patients, the function and configuration of the pouch should be feasible; however, the distal ileum may not be long enough for a re-do J-pouch or a new Kock pouch. In this situation, conversion using the original pouch is reasonable and feasible. To some degree, only about 15 cm of distal ileum will be applied for the construction of the nipple valve and exit conduit.

Indications of Excising the Original Failed Pouch : Some intractable lesions in the pouch may lead to eventual pouch excision. Conversion to the Kock pouch should be done by reconstructing a new pouch with no hesitation. However, the prerequisite in this situation is that there is sufficient ileum left for pouch formation. Approximately 60 cm of distal ileum will be used for a new pouch construction. Intractable conditions leading to pouch failure include but are not limited to pouch fistula, stricture, pouchitis, dysplasia, and cancer.

Contraindications

In patients who intend to be converted from a failed J-pouch to a Kock pouch, all contraindications to the primary construction of a Kock pouch should be seriously followed. In addition, contraindications related to reconstruction with the Kock pouch are also taken into account.

Crohn’s Disease With Small Bowel Involved : Similar to that in CD patients with a pelvic pouch, a previous study also indicated that Kock pouch patients on the background of CD had high rates of pouch fistula as well as resistant or recurrent pouchitis which might lead to pouch failure. Patients with the manifestation of CD in the small bowel are not suitable for the Kock pouch.

Potential Risk of SBS : For patients with the potential risk of SBS, conversion from a J-pouch to a Kock pouch is not suitable since some segments of the small bowel are still required for the reconstruction regardless of whether the previous pouch is excised or preserved. In this extreme situation, end ileostomy might be an alternative.

Urgent Surgery for Acute Severe Colitis or Pouch-Related Complications : Kock pouch construction should be avoided in the acute setting given the additional time required in these sick patients. Removing the sick pouch or bowel segment followed by an end ileostomy is the initial choice with a Kock pouch considered at the second stage of the surgery after the patients recover from their illness.

Inability to Manage Stoma Intubation : For patients with a Kock pouch, the ability to handle intubation is acquired. Patients should be well-informed before surgery. The procedure should be contraindicated to those who are unable to understand such essential information. In addition, children and patients with learning difficulties or those with their extremities precluding intubation are unsuitable for the Kock pouch.

Skin Lesions in Abdominal Wall : Some skin lesions, such as pyoderma gangrenosum, may prevent a good recovery from Kock pouch surgery, and even exert harmful effects.

Indications and contraindications for conversion of J-pouch to Kock pouch were listed in Table 32.2 .

Table 32.2

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