Surgical strategy for complex perineal small bowel fistula after pelvic malignancy: An etiology-driven approach

Table 1 Comparison of patient characteristics by surgical group, n (%)/mean ± SD

Characteristic	Group 1: Reconstruction (n = 15)	Group 2: Plication (n = 13)	P value
Race/ethnicity
Han Chinese	15 (100)	13 (100)
Age in years	58.7 ± 13.2	54.2 ± 11.9	0.36
Sex			0.47
Male	6 (40.0)	7 (53.8)
Female	9 (60.0)	6 (46.2)
Primary malignancy			0.73
Rectal/colorectal	8 (53.3)	9 (69.2)
Gynecological: Cervix/ovary	6 (40.0)	4 (30.8)
Other: Sarcoma/bladder	1 (6.7)	0 (0.0)
History of radiotherapy			0.69
Yes	9 (60)	9 (69.2)
No	6 (40)	4 (30.8)
Primary fistula etiology			0.02a
Empty pelvis syndrome	3 (20.0)	0 (0.0)
Tumor recurrence	4 (26.7)	8 (61.5)
Radiation enteritis	5 (33.3)	4 (30.8)
Surgical/iatrogenic injury	2 (13.3)	1 (7.7)
Other: Internal radiation	1 (6.7)	0 (0.0)

^aP < 0.05.

Data are n (%) unless indicated otherwise, presenting comparative demographic and baseline clinical variables between patients undergoing pelvic floor reconstruction (Group 1) and internal intestinal plication (group 2). Statistical significance was evaluated using the independent Student's t-test for continuous variables and Fisher’s exact test for categorical variables. While demographic parameters were statistically identical, the primary etiology of the fistula demonstrated a significant divergence (P = 0.02), validating the core premise that the surgical strategy was heavily driven by the underlying pathophysiological mechanism.

Table 2 Correlation between fistula etiology and surgical strategy, n (%)

Etiology	Total, n	Group 1: Reconstruction	Group 2: Plication	Dominant strategy
Empty pelvis syndrome	3	3 (100)	0 (0)	Reconstruction
Tumor recurrence	12	4 (33.3)	8 (66.7)	Plication
Radiation enteritis	9	5 (55.6)	4 (44.4)	Mixed
Surgical/iatrogenic injury	3	2 (66.7)	1 (33.3)	Reconstruction
Internal radiation: Seeds	1	1 (100)	0 (0)	Reconstruction
Total	28	15 (53.6)	13 (46.4)

Stratification of patients based on the dominant pathophysiological driver of the perineal small bowel fistula. The data illustrate strict adherence to an etiology-driven algorithm, where pure structural defects (empty pelvis syndrome) universally trigger reconstructive flap techniques, whereas recurrent, adhesive malignant disease predominantly necessitates the physiological stenting provided by intestinal plication.

Table 3 Odds ratio analysis for the selection of internal intestinal plication

Variable: Predictor	Reconstruction (n = 15)	Plication (n = 13)	OR	95%CI	P value
Tumor recurrence	4	8	4.00	0.77-20.8	0.09
Radiation enteritis	5	4	0.75	0.13-4.23	0.74
Empty pelvis syndrome	3	0	0.00	0.00-NA	0.23
Surgical injury	2	1	0.43	0.03-5.56	0.52

Multivariate evaluation assessing the likelihood of a specific pathology dictating the use of internal intestinal plication. Tumor recurrence represents the strongest clinical predictor for selecting plication, reflecting the surgical necessity to manage diffuse, malignant adhesive disease rather than attempting to fill a non-existent pelvic void. Patients with tumor recurrence had 4-fold higher odds of undergoing internal intestinal plication (group 2) compared to reconstruction, reflecting the preference for plication in frozen, malignant pelvises. OR: Odds ratio; CI: Confidence interval; NA: Not applicable.

Table 4 Postoperative clinical outcomes, n (%)/median (minimum-maximum)/mean ± SD

Outcome measure	Group 1: Reconstruction (n = 15)	Group 2: Plication (n = 13)	Total (n = 28)	P value
Fistula closure rate	13 (86.7)	12 (92.3)	25 (89.3)	1.0
Duration of follow-up/OS in months1	32.0 (9.0-107.0)	37.0 (11.0-57.0)	34.5 (9.0-107.0)	0.66
90-day mortality	1 (6.7)	1 (7.7)	2 (7.1)	1.0
Postoperative flatus in days	4.2 ± 1.5	6.8 ± 2.1	5.4 ± 2.2	0.0021
Complications, by Clavien-Dindo				0.65
Grade I-II: Minor	4 (26.7)	5 (38.5)	9 (32.1)
Grade III-IV: Major	4 (26.7)	3 (23.1)	7 (25.0)
Stoma status at discharge
Stoma free/reversed	3 (20.0)	1 (7.7)	4 (14.3)
Permanent/temporary stoma	12 (80.0)	12 (92.3)	24 (85.7)

¹Continuous variables are presented as the mean ± SD; P-value is from the Student’s t-test.

Summary of critical postoperative outcomes. Both techniques demonstrated exceptionally high success rates in achieving durable fistula closure with no statistical superiority. However, group 2 (plication) experienced significantly longer time to flatus, consistent with the postoperative ileus often being associated with extensive intestinal manipulation. Continuous variables are presented as the median (range) due to non-normal distribution; P-values were calculated using the two-sample Wilcoxon/Mann-Whitney U test. OS: Overall survival.