Role of tissue expanders in patients with loss of abdominal domain awaiting intestinal transplantation

Multilevel Analysis of the Neovascularization and Integration Process of a Nonvascularized Rectus Fascia Transplantation

Background

Failure to close the abdominal wall after intestinal transplantation (ITx) or multivisceral Tx remains a surgical challenge. An attractive method is the use of nonvascularized rectus fascia (NVRF) in which both layers of the donor abdominal rectus fascia are used as an inlay patch without vascular anastomosis. How this graft integrates over time remains unknown. The study aims to provide a multilevel analysis of the neovascularization and integration process of the NVRF.

Methods

Three NVRF-Tx were performed after ITx. Clinical, radiological, histological, and immunological data were analyzed to get insights into the neovascularization and integration process of the NVRF. Moreover, cryogenic contrast-enhanced microfocus computed tomography (microCT) analysis was used for detailed reconstruction of the vasculature in and around the NVRF (3-dimensional histology).

Results

Two men (31- and 51-y-old) and 1 woman (49-y-old) underwent 2 multivisceral Tx and 1 combined liver-ITx, respectively. A CT scan showed contrast enhancement around the fascia graft at 5 days post-Tx. At 6 weeks, newly formed blood vessels were visualized around the graft with Doppler ultrasound. Biopsies at 2 weeks post-Tx revealed inflammation around the NVRF and early fibrosis. At 6 months, classical 2-dimensional histological analysis of a biopsy confirmed integration of the fascia graft with strong fibrotic reaction without signs of rejection. A cryogenic contrast-enhanced microCT scan of the same biopsy revealed the presence of microvasculature, enveloping and penetrating the donor fascia.

Conclusions

We showed clinical, histological, and microCT evidence of the neovascularization and integration process of the NVRF after Tx.

Potential options to expand the intestinal donor pool: a comprehensive review

PURPOSE OF REVIEW

Intestinal donation is currently restricted to 'perfect' donors, as the intestine is extremely vulnerable to ischemia. With generally deteriorating donor quality and increasing indications for intestinal transplantation (ITx), the potential to safely increase the donor pool should be evaluated.

RECENT FINDINGS

Increasing awareness on intestinal donation (often forgotten) and cautiously broadening the strict donor criteria (increasing age, resuscitation time and ICU stay) could expand the potential donor pool. Donors after circulatory death (DCD) have so far not been considered for ITx, due to the particularly detrimental effect of warm ischemia on the intestine. However, normothermic regional perfusion might be a well tolerated strategy to render the use of DCD intestinal grafts feasible. Furthermore, machine perfusion is under continuous development and might improve preservation of the intestine and potentially offer a platform to modulate the intestinal graft. Lastly, living donation currently represents only a minority of all ITxs performed worldwide. Various studies and registry analysis show that it can be performed safely for the donor and successfully in the recipient.

SUMMARY

Several potential strategies are available to expand the current intestinal donor pool. Most of them require further investigation or technical developments before they can be implemented in the clinical routine.

Using Radiographic Domain for Evaluating Indications in Abdominal Wall Transplantation

BACKGROUND

There is currently no description of abdominal domain changes in small bowel transplantation population or consensus of criteria regarding which patients are at high risk for immediate postoperative abdominal wall complications or would benefit from abdominal wall vascularized composite allotransplantation.

METHODS

A retrospective chart review was performed on 14 adult patients receiving intestinal or multivisceral transplantation. Preoperative and postoperative computed tomography scans were reviewed, and multiple variables were collected regarding abdominal domain and volume and analyzed comparing postoperative changes and abdominal wall complications.

RESULTS

Patients after intestinal or multivisceral transplantation had a mean reduction in overall intraperitoneal volume in the immediate postoperative period from 9031 cm3 to 7846 cm3 (P = 0.314). This intraperitoneal volume was further reduced to an average of 6261 cm3 upon radiographic evaluation greater than 1 year postoperatively (P = 0.024). Patients with preexisting abdominal wound (P = 0.002), radiation, or presence of ostomy (P = 0.047) were significantly associated with postoperative abdominal wall complications. No preoperative radiographic findings had a significant association with postoperative abdominal wall complications.

CONCLUSIONS

Computed tomography imaging demonstrates that intestinal and multivisceral transplant patients have significant reduction in intraperitoneal volume and domain after transplantation in the acute and delayed postoperative setting. Preoperative radiographic abdominal domain was not able to predict patients with postoperative abdominal wall complications. Patients with abdominal wounds, ostomies, and preoperative radiation therapy were associated with acute postoperative abdominal complications and may be considered for need of reconstructive techniques including abdominal wall transplantation.

Definitions for Loss of Domain: An International Delphi Consensus of Expert Surgeons

BACKGROUND

No standardized written or volumetric definition exists for 'loss of domain' (LOD). This limits the utility of LOD as a morphological descriptor and as a predictor of peri- and postoperative outcomes. Consequently, our aim was to establish definitions for LOD via consensus of expert abdominal wall surgeons.

METHODS

A Delphi study involving 20 internationally recognized abdominal wall reconstruction (AWR) surgeons was performed. Four written and two volumetric definitions of LOD were identified via systematic review. Panelists completed a questionnaire that suggested these definitions as standardized definitions of LOD. Consensus on a preferred term was pre-defined as achieved when selected by ≥80% of panelists. Terms scoring <20% were removed.

RESULTS

Voting commenced August 2018 and was completed in January 2019. Written definition: During Round 1, two definitions were removed and seven new definitions were suggested, leaving nine definitions for consideration. For Round 2, panelists were asked to select all appealing definitions. Thereafter, common concepts were identified during analysis, from which the facilitators advanced a new written definition. This received 100% agreement in Round 3. Volumetric definition: Initially, panelists were evenly split, but consensus for the Sabbagh method was achieved. Panelists could not reach consensus regarding a threshold LOD value that would preclude surgery.

CONCLUSIONS

Consensus for written and volumetric definitions of LOD was achieved from 20 internationally recognized AWR surgeons. Adoption of these definitions will help standardize the use of LOD for both clinical and academic activities.

Systematic Review of Tissue Expansion: Utilization in Non-breast Applications

Background

Tissue expansion is a versatile reconstructive technique providing well-vascularized local tissue. The current literature focuses largely on tissue expansion for breast reconstruction and in the context of burn and pediatric skin/soft tissue replacement; however, less traditional applications are also prevalent. The aim of this study was to systematically review the utilization of tissue expansion in such less well-characterized circumstances.

Methods

The authors conducted a systematic review of all publications describing non-breast applications of tissue expansion. Variables regarding expander specifications, expansion process, and complications were collected and further analyzed.

Results

A total of 565 publications were identified. Of these, 166 publications described tissue expansion for "less traditional" indications, which fell into 5 categories: ear reconstruction, cranioplasty, abdominal wall reconstruction, orthopedic procedures, and genital (penile/scrotal and vaginal/vulva) reconstruction. While lower extremity expansion is known to have high complication rates, tissue expander failure, infection, and exposure rates were in fact highest for penile/scrotal (failure: 18.5%; infection: 15.5%; exposure: 12.5%) and vaginal/vulva (failure: 20.6%; infection: 10.3%; exposure: 6.9%) reconstruction.

Conclusions

Tissue expansion enables index operations by providing additional skin before definitive reconstruction. Tissue expanders are a valuable option along the reconstructive ladder because they obviate the need for free tissue transfer. Although tissue expansion comes with inherent risk, aggregate outcome failures of the final reconstruction are similar to published rates of complications without pre-expansion. Thus, although tissue expansion requires a staged approach, it remains a valuable option in facilitating a variety of reconstructive procedures.

Intestinal re-transplantation: indications, techniques and outcomes

PURPOSE OF REVIEW

The field of intestinal transplantation has shown significant growth and has become the gold standard therapy for patients that suffer from the complications of total parenteral nutrition due to irreversible intestinal failure. In the early years of intestinal transplant, retransplantation was associated with extremely high morbidity and mortality. The purpose of this review is to summarize recent encouraging reports, showing significant improvement in outcomes after intestinal retransplantation.

RECENT FINDINGS

Recent studies at large volume centers have reported significant progress in patient and graft survival after intestinal retransplantation. Recent literature described the most common indications for retransplantation, surgical techniques, timing of graft enterectomy, immunologic monitoring, and complications. Improvement in outcomes due to advances in immunosuppression management and the importance of liver-containing grafts are also described.

SUMMARY

Improving early to midterm patient and graft survival has made consideration for intestinal retransplantation even more necessary. Current clinical evidence supports the benefit of intestinal retransplantation in well selected recipients. Initial immunosuppression protocols, technical modifications, proper timing of enterectomy, and improved infectious disease monitoring have contributed to improved outcomes.

Composite and Multivisceral Transplantation: Nomenclature, Surgical Techniques, Current Practice, and Long-term Outcome

The successful development of multivisceral and composite visceral transplantation is among the milestones in the recent history of human organ transplantation. All types of gastrointestinal transplantation have evolved to be the standard of care for patients with gut failure and complex abdominal pathologic conditions. The outcome has markedly improved over the last 3 decades owing to technical innovation, novel immunosuppression, and better postoperative care. Recent data documented significant improvement in the long-term therapeutic indices of all types of visceral transplantation close to that achieved with thoracic and solid abdominal organs.

Composite and Multivisceral Transplantation: Nomenclature, Surgical Techniques, Current Practice, and Long-term Outcome

The successful development of multivisceral and composite visceral transplantation is among the milestones in the recent history of human organ transplantation. All types of gastrointestinal transplantation have evolved to be the standard of care for patients with gut failure and complex abdominal pathologic conditions. The outcome has markedly improved over the last 3 decades owing to technical innovation, novel immunosuppression, and better postoperative care. Recent data documented significant improvement in the long-term therapeutic indices of all types of visceral transplantation close to that achieved with thoracic and solid abdominal organs.

Small-for-size Syndrome Does Not Occur in Intestinal Transplantation Without Liver Containing Grafts

BACKGROUND

The ideal donor in intestinal transplantation (ITX) is generally considered to be 50% to 70% of recipient body weight. This may be due to concerns for "small for size" syndrome as seen in liver transplantation. We report our experience using smaller donors (donor-recipient weight ratio [DRWR], < 50%) in ITX recipients.

METHODS

We studied a group of ITX recipients with DRWR of 50% or less to unmatched controls who received intestinal allografts with DRWR greater than 50%. We examined patient and graft survival and enteral autonomy from parenteral nutrition as surrogate markers for safety of using smaller donors and ease of abdominal wall closure between groups to determine the value.

RESULTS

There was no difference in overall patient and graft survival, time to enteral autonomy from parenteral nutrition, and weight gain after ITX over time between groups. The need for complicated abdominal closure techniques was significantly more frequent in the control group than in the study group (34.6% vs 6.9%, P = 0.01). Secondary abdominal closure occurred more frequently in the control group (15.4% vs 0%, P = 0.014). Wound revisions also occurred more frequently in the control group (15.4% vs 0%, P = 0.028).

CONCLUSIONS

Our data suggest that ITX using smaller donors (DRWR ≤ 50%) seems to be an acceptable practice without adverse impact on surgical complications, nutritional autonomy, and patient and graft survival. Abdominal wall closure seems easier in recipients of smaller donors and "small for size" syndrome as described in liver transplantation does not occur with intestinal allografts.

Advances in small bowel transplantation

Small bowel transplantation is a life-saving surgery for patients with intestinal failure. The biggest problem in intestinal transplantation is graft rejection. Graft rejection is the main reason for morbidity and mortality. Rejection has a negative effect on the survival of the graft. While 50%-75% of small bowel transplantation patients experience acute rejection, chronic rejection occurs in approximately 15% of patients. Immune monitoring is crucial after small bowel transplantation. Unlike other types of transplantation, there are no non-invasive or reliable markers to predict rejection in small bowel transplantation. The diagnosis of AR is confirmed by clinical symptoms, endoscopic appearance, and pathological specimens taken by endoscopy. Thus, histopathological examinations obtained by protocol biopsies remain as the gold standard for intestinal graft monitoring; however, biopsies have some complications, especially in small grafts. In addition to the high complication rate, biopsies are non-diagnostic; thus, multiple biopsies should be performed to exclude rejection. Therefore, auxiliary assays, such as measurements of citrulline and calprotectin in the blood, cytofluorographic examination of peripheral blood immune cells, cytokine profiling, and distinct gene-set-change measurements, are increasingly being used in small bowel transplantation. Developments in the understanding of genes seem to be promising that limited gene sets, taken from blood or from intestinal biopsies, will enhance pathological diagnosis. Bone marrow mesenchymal stem cell transplantation with SBT and tissue engineering are also promising procedures.

Anesthesia for Intestinal Transplantation

The diagnosis of irreversible intestinal failure confers significant morbidity, mortality, and decreased quality of life. Patients with irreversible intestinal failure may be treated with intestinal transplantation. Intestinal transplantation may include intestine only, liver-intestine, or other visceral elements. Intestinal transplantation candidates present with systemic manifestations of intestinal failure requiring multidisciplinary evaluation at an intestinal transplantation center. Central access may be difficult in intestinal transplantation candidates. Intestinal transplantation is a complex operation with potential for hemodynamic and metabolic instability. Patient and graft survival are improving, but graft failure remains the most common postoperative complication.

Role of tissue expansion in abdominal wall reconstruction: A systematic evidence-based review

BACKGROUND

Tissue expanders (TEs) can be used to assist primary closure of complicated hernias and large abdominal wall defects. However, there is no consensus regarding the optimal technique, use, or associated risk of TE in abdominal wall reconstruction.

METHODS

A systematic search of PubMed and Embase databases was conducted to identify articles reporting abdominal wall reconstruction with TE techniques. English articles published between 1980 and 2016 were included on the basis of the following inclusion criteria: two-stage TE surgical technique, >3 cases, reporting of postoperative complications, hernia recurrence, and patient-based clinical data.

RESULTS

Fourteen studies containing 103 patients (85 adults and 18 children) were identified for analysis. Most patients presented with a skin-grafted ventral hernia (n = 86). The etiology of the hernia was from trauma or prior abdominal surgery. The remaining patients had TE placed before organ transplantation (n = 12) or for congenital abdominal wall defects (n = 5). The location for expander placement was subcutaneous (n = 74), between the internal and external obliques (n = 26), posterior to the rectus sheath (n = 2), and intra-peritoneal (n = 1). Postoperative infections and implant-related problems were the most commonly reported complications after Stage I. The most common complication after Stage II was recurrent hernia, which was observed in 12 patients (11.7%). Five patients with TE died. Complications and mortality were more prevalent in children, immunosuppressed patients, and those with chronic illnesses.

CONCLUSIONS

Tissue expansion for abdominal wall reconstruction can be successfully used for a variety of carefully selected patients with an acceptable complication and risk profile.

Current status of intestinal and multivisceral transplantation

Clinical-nutritional autonomy is the ultimate goal of patients with intestinal failure (IF). Traditionally, patients with IF have been relegated to lifelong parenteral nutrition (PN) once surgical and medical rehabilitation attempts at intestinal adaptation have failed. Over the past two decades, however, outcome improvements in intestinal transplantation have added another dimension to the therapeutic armamentarium in the field of gut rehabilitation. This has become possible through relentless efforts in the standardization of surgical techniques, advancements in immunosuppressive therapies and induction protocols and improvement in postoperative patient care. Four types of intestinal transplants include isolated small bowel transplant, liver-small bowel transplant, multivisceral transplant and modified multivisceral transplant. Current guidelines restrict intestinal transplantation to patients who have had significant complications from PN including liver failure and repeated infections. From an experimental stage to the currently established therapeutic modality for patients with advanced IF, outcome improvements have also been possible due to the introduction of tacrolimus in the early 1990s. Studies have shown that intestinal transplant is cost-effective within 1-3 years of graft survival compared with PN. Improved survival and quality of life as well as resumption of an oral diet should enable intestinal transplantation to be an important option for patients with IF in addition to continued rehabilitation. Future research should focus on detecting biomarkers of early rejection, enhanced immunosuppression protocols, improved postoperative care and early referral to transplant centers.

The role of osmotic self-inflatable tissue expanders in intestinal transplant candidates

Intestinal transplantation (ITx) is often associated with decreased abdominal domain, rendering abdominal closure difficult. Pre-transplant placement of tissue expanders (TE) can overcome this challenge; however it can be associated with life-threatening complications. This review aimed to comprehensively summarize all available literature on TE in ITx candidates and include the technical details of osmotic, self-inflatable TE -a technique undescribed before. PubMed, EMBASE and CCTR were searched until April 30, 2016. Based on structured data abstraction and detailed analysis, eighteen cases of TE (inflatable) in ITx candidates were found. Localisation of placement was: subcutaneously in 11; intraperitoneally in 4; 1 patient had 1 TE placed retromuscularly and 1 intraperitoneally; 1 patient had biplanar TE (intraperitoneally placed and extending retromuscularly) and in 1 localisation was unreported. Complication rate was high (61%), injection- or intraperitoneal-related, resulting in life-threatening infections/hematoma. With successful expansion, physiological graft protection -by skin+/-fascia- was always achieved. In completion of this review, we describe our own experience with two patients (7.5-, 34-year-old females), in whom osmotic TE were placed subcutaneously pre-ITx. No TE-related complications occurred and both patients underwent uncomplicated ITx with respectively primary skin and skin + fascia closure. The pros and cons of each TE type and placement are discussed, resulting in the overall conclusions that TE offer an important benefit in graft-protection following ITx. Osmotic TE are safer than conventional prostheses by avoiding percutaneous injections. Subcutaneous placement seems to be safer and more reliable.

Intestinal transplantation

Intestinal transplantation has now emerged as a lifesaving therapeutic option and standard of care for patients with irreversible intestinal failure. Improvement in survival over the years has justified expansion of the indications for intestinal transplantation beyond the original indications approved by Center for Medicare and Medicaid services. Management of patients with intestinal failure is complex and requires a multidisciplinary approach to accurately select candidates who would benefit from rehabilitation versus transplantation. Significant strides have been made in patient and graft survival with several advancements in the perioperative management through timely referral, improved patient selection, refinement in the surgical techniques and better understanding of the immunopathology of intestinal transplantation. The therapeutic efficacy of the procedure is well evident from continuous improvements in functional status, quality of life and cost-effectiveness of the procedure. This current review summarizes various aspects including current practices and evidence based recommendations of intestinal transplantation.

The concept of gut rehabilitation and the future of visceral transplantation

In the 1990s, the introduction of visceral transplantation fuelled interest in other innovative therapeutic modalities for gut rehabilitation. Ethanol lock and omega-3 lipid formulations were introduced to reduce the risks associated with total parenteral nutrition (TPN). Autologous surgical reconstruction and bowel lengthening have been increasingly utilized for patients with complex abdominal pathology and short-bowel syndrome. Glucagon-like peptide 2 analogue, along with growth hormone, are available to enhance gut adaptation and achieve nutritional autonomy. Intestinal transplantation continues to be limited to a rescue therapy for patients with TPN failure. Nonetheless, survival outcomes have substantially improved with advances in surgical techniques, immunosuppressive strategies and postoperative management. Furthermore, both nutritional autonomy and quality of life can be restored for more than two decades in most survivors, with social support and inclusion of the liver being favourable predictors of long-term outcome. One of the current challenges is the discovery of biomarkers to diagnose early rejection and further improve liver-free allograft survival. Currently, chronic rejection with persistence of preformed and development of de novo donor-specific antibodies is a major barrier to long-term graft function; this issue might be overcome with innovative immunological and tolerogenic strategies. This Review discusses advances in the field of gut rehabilitation, including intestinal transplantation, and highlights future challenges. With the growing interest in individualized medicine and the value of health care, a novel management algorithm is proposed to optimize patient care through an integrated multidisciplinary team approach.

The use of bi-planar tissue expanders to augment abdominal domain in a pediatric intestinal transplant recipient

Intestinal transplantation is a well-accepted treatment for SBS. However, patients with SBS often have decreased abdominal capacity, which makes size-matching of donor organs more difficult, thus decreasing organ availability. Reported approaches for addressing this problem include surgically reducing the graft size, leaving an open abdomen for a prolonged period, and cotransplanting rectus fascia as a non-vascularized allograft. Each approach has significant disadvantages. There has been one previous report of tissue expanders used intra-abdominally and two reports of subcutaneous use to increase intra-abdominal capacity prior to transplantation. We report the first use of bi-planar expander placement for this purpose. In our case, a two-yr-old male child with SBS due to malrotation was treated with tissue expanders 10 months prior to intestinal transplantation, thus allowing transplantation of a larger graft with the ability to close the abdomen safely. There were no complications, and the patient is now doing well and tolerating diet off PN. The use of tissue expanders prior to intestinal transplantation is a promising approach for such patients and avoids the morbidity associated with other approaches. This approach requires a multidisciplinary effort by gastroenterology, transplant surgery, and plastic surgery teams.