Study characteristics. Of the 983 articles identified in the literature search, 57 underwent critical appraisal using the JBI checklist for case series. No randomized controlled trials were found among the 15 level IV case-based publications that met the inclusion criteria. Eleven (11) retrospective studies11,13-17,34-38 and 1 prospective39 study were included; 3 studies were unclear in their design9,40,41 (see Table and continued). All studies took place in a hospital setting,9,11,13-17,34-41; 1 study38 included intensive care unit patients exclusively. Studies were conducted in Italy,13,14 Turkey,37,40,41 Brazil,36 Argentina,34,35 Germany,38 the United States,9,11,13,15 Poland,36 and Australia.16
Participant characteristics. The 410 participants (179 male, 100 female, gender not provided for 131) ranged from 14 to 89 years of age.9,11,13-17,34-41 All participants had an ECF/EAF resulting from a postoperative complication of abdominal surgery.9,11,13-17,34-41 Of the 559 fistulas treated in this study, 337 originated in the small bowel, 49 originated in the large bowel, 59 were gastroduodenal, and 121 were of unclear origin.9,11,13-17,34-41 The number of fistulas per participant varied from 1 to 8.9,11,13-17,34-41
Eight (8) of the studies classified output as low (<200 mL/24 hours), moderate (200 mL/24 hours to 500 mL/24 hours), or high (>500 mL/24 hours)11,15,17,34,36,38,39,41; 3 studies classified output as low (<200 mL/24 hours) or high (>200 mL/24 hours)13,14,16; 1 study classified output as low (<500 mL/24 hours) or high (>500 mL/24 hours)37; and 3 were unclear in the reporting of output classification.9,35,40
In the 4 studies that reported participant recruitment, 94 of the 132 participants were transferred from an outside facility.16,24,34,36 The remaining 11 studies did not specify the source of participant recruitment.9,11,13-15,17,35,37-41
Study quality. All 15 publications were level IV (case series).9,11,13-17,34-41 Using the JBI checklist for case series, the current authors found that each study was at high risk of bias in more than 2 domains (see Table and continued).
Selection9,11,13-17,34,36,37,38,40,41 and reporting bias13,14,16,40 were prevalent; data regarding participant demographics and clinical information were consistently reported.9,11,13-17,34-41
Topical intervention. Various NPWT methods were used as the primary intervention across all studies.9,11,13-17,34-41 For organizational purposes, review authors categorized interventions as isolating, intubating, or occluding the fistula (see Table and continued).
Fistula isolation. Fistula isolation was described as diverting the effluent from the perifistula tissue. This was achieved by cutting the NPWT foam to surround the fistula.9,36,37,38,41 NPWT was applied at pressures ranging from -75 mm Hg to -125 mm Hg, and the fistula was pouched with an ostomy appliance to manage effluent.9,11,36,37,38,40,41 If the fistula output was high, a catheter was inserted into the pouch and low wall suction was applied.9,11,40 In order to achieve a seal with NPWT, ostomy accessories or commercial fistula isolation adaptors were used.11,38,40 The isolation technique was used in patients where spontaneous closure was not expected9,36 as a means of managing effluent until surgical intervention11,38 and in the presence of mature mucosa.36-38
Fistula intubation. Fistula intubation was described as the insertion of a Jackson Pratt (JP) drain16 or Foley catheter36,39 into the fistula orifice. Negative pressure was applied to the collection tubing using -125 mm Hg16 and -600 mm Hg.39 In 2 studies, NPWT then was applied around the intubated fistula.16,36 This technique was used as a means of achieving spontaneous closure16,37and for managing effluent until surgical closure.16,36
Fistula occlusion. Fistula occlusion was described as the application of NPWT directly over the fistula orifice and surrounding tissue. Settings ranged from -50 mm Hg to -600 mm Hg.13-15,17,34-38 This technique was applied to non-mature37,38 or both mature and non-mature fistulas14,15,34,35 as a means of managing effluent while awaiting spontaneous closure or surgical closure.
When a fistula reached maturation, 3 reviewed study authors reported changing the intervention from the occlusion to isolation with pouching.36-38 Some study authors reported changing technique when granulation tissue appeared, switching patients from a vacuum aspiration system (VAS) to a sistema de vacio y compactacion (vacuum and compactions system) (SIVACO) once healthy tissue covered the abdominal viscera.35
Perifistula protection. Products used to protect perifistula tissue included ostomy paste9,11,35-38,41 (162), powder9 (2), and spray15 (15), as well as hydrocolloid rings11,38,40 (15) and sheets40 (3). Three (3) studies reported perifistula dermatitis resolution among 104 study participants when an adequately sealed NPWT and collection device system was implemented.11,13,34
Effluent management. Effluent management was described in all studies9,11,13-17,34-41; 8 studies reported output reduction during fistula occlusion,13,15,17,34-38 and 2 reported no increase in output after initiation of therapy.11,13 Two (2) studies quantitatively measured output reduction throughout the intervention and attributed this reduction to occlusion of the fistula orifice.34,35 No other measurement of output was reported.
In addition, TPN, somatostatin, and octreotide commonly are used in ECF/EAF care and may contribute to successful closure.6,21,25 Somatostatin and octreotide were used in 8 studies in this review.13,14,36,37,39 The use of any other anti-secretory agents was not reported. TPN was reportedly used in all studies.9,11,34-17,34-41
Dressing change frequency. Dressing change frequency ranged from 2 to 5 days and was reported to be based on the selected products’ ability to maintain NPWT system integrity; as a result, no established frequency could be reported.9,11,13-17,34-41 In 5 studies,9,11,13,40 wound healing information was limited to the narrative reporting of improved granulation tissue and wound contracture. One (1) author9 provided wound healing data on 1 study participant, noting a reduction in wound size from 34 cm x 39 cm x 4 cm to 10 cm x 11 cm x 0.25 cm over a 7-week period.
NPWT options. A multitude of NPWT systems were identified in the reviewed literature and included V.A.C. systems (3M + KCI),9,11,14-17,36,37,40 Renasys AB (Smith and Nephew),36 VivanoMed Abdominal Kit (Paul Hartmann AG),36 collection and pressure flasks,39 SIVACO (Spanish acronym),34,35 and VAS (Spanish acronym).35 Pressure settings were equally variable and ranged from -50 mm Hg to -600 mm Hg. A nonadherent mesh often was used between the NPWT foam and ECF/EAF to protect the fistula mucosa9,37 and wound bed.9,11,15,17,36-39,41 Duration of NPWT ranged from 8 to 370 days.15-17,34,36,37,39-41 NPWT setting was specified in 4 studies; 1 used both continuous and intermittent settings,36 and 3 used only the continuous setting.14,36,41 The remaining 11 did not specify the NPWT setting.9,11,13,15-17,34,35,37-40
Spontaneous closure. Spontaneous closure was the primary outcome in 12 of the 15 studies (164 patients), and rates ranged from 0% to 100%.11,14-17,34-40 The time from diagnosis to spontaneous closure ranged from 9 days to 1 year.11,14-17,34,35-40 Mature mucosa was reported as a key barrier to spontaneous closure in 4 studies.15,35,36,37
Surgical closure. Surgical closure was reported in 11 studies involving a total of 210 patients.11,14,16,34-41 The time to surgical closure ranged from 40 days to 6 years.11,14,16,34-41
Long-term management. The 10 participants described in 4 studies who did not achieve closure were reported to have managed the fistula with an ostomy appliance long-term.11,35,38,41
Adverse events. Pain34 and new fistula formation9,34,36 were reported as adverse events that occurred during topical management. One (1) study,34 involving 33 participants, included the evaluation of patient pain and the provision of analgesia; complications second to analgesia administration were the primary adverse events in the study. One study16 (N = 9) reported the use of sedation and intravenous analgesia during dressing changes but the authors did not report pain evaluations. New fistula formation was reported in 4 studies (N = 171) among 12 patients.9,34,35,36 Fistula recurrence was reported as a complication after spontaneous closure in 1 study involving 3 patients; 1 fistula reoccurred.40 One (1) author9 reported tissue breakdown and maceration of perifistula skin within 6 hours of stopping NPWT in 2 study participants. No studies measured pain using a standardized tool, quality of life, or patient satisfaction regarding any 1 intervention.
Duration of follow-up. The duration of follow-up was provided in 7 studies and ranged from 3 to 36 months.11,14-16,34,37,40 Two (2) of these studies16,37 clearly stated whether follow-up included all participants; 1 study16 followed 9 participants for a median of 20 months to determine spontaneous or surgical closure, and the other only measured the incidence of ventral hernia during follow up.37 No study specified a time to determine closure.9,11,13-17,34-41
Mortality. In this review, no deaths were reported to be directly related to topical management9,11,13,17,34-41; 29 participants died of sepsis,13,16,34,38,41 which was the leading cause of mortality. The mortality rate in all included studies ranged from 0% to 44%.9,11,13-17, 34-41