Incidental urinary tract injury and the formation of vesicovaginal fistula at the time of hysterectomy for benign indications

Abstract

Introduction and Hypothesis

The association between hysterectomy type, laparoscopy use, and vesicovaginal fistula (VVF) is currently unclear, and would be useful to determine route of surgery and provide adequate patient counseling. The objective of this study was to evaluate the magnitude of association between the use of laparoscopic assistance, recognized intraoperative urinary tract injury, and subsequent VVF repair and to quantify any differences in fistula repair and injury detection by hysterectomy type. Lastly, we sought to determine if the type of hysterectomy is a risk factor for VVF repair independent of injury identification.

Methods

We performed a retrospective cohort study utilizing the Healthcare Cost and Utilization Project database examining benign hysterectomies performed in California, New York and Florida from 2005–2011. Multivariable logistic regression models were used to evaluate associations between hysterectomy type, reported injury, and VVF.

Results

Of 581,395 eligible hysterectomies, urinary tract injuries occurred in 6,702 patients (1.15%) and 640 patients developed VVF (0.11%). Patients with reported injury were 20-fold more likely to develop VVF than those without (OR=20.6). The association between reported injury and VVF development was stronger if laparoscopy was involved (OR=30) than if it did not (OR=17). Patients undergoing laparoscopic procedures were less likely to have injury reported (OR=0.6) but more likely to undergo VVF repair (OR=1.5). This association with VVF repair was independent of injury identification. Patients developing VVF were more likely to have undergone total abdominal hysterectomy compared to other hysterectomy types.

Conclusion

Laparoscopy is an independent risk factor for the need for subsequent VVF repair, independent of hysterectomy type and presence of intraoperatively recognized urinary tract injury.

BRIEF SUMMARY

Laparoscopy is associated with reduced injury detection during surgery and increased risk of subsequent VVF repair. This association varies by subtype of hysterectomy performed.

INTRODUCTION

Vesicovaginal fistula (VVF), an abnormal channel between the bladder and the vagina, results in continuous leakage of urine from the vagina. Incidence of VVF after benign hysterectomy ranges from 0.1% to 0.28%, yet hysterectomy accounts for up to 82% of VVF cases, suggesting injury to the urinary tract during hysterectomy as the main cause [1–11]. A systematic review examining the incidence of urinary tract injuries associated with laparoscopic hysterectomy found 3.4% of injuries resulted in a VVF [12]. Previous studies assess risk associated between laparoscopy use and injury [8] and risk associated between laparoscopy use and VVF [6] separately. Collectively, these studies report paradoxical findings, where laparoscopy is associated with lower risk of injury during hysterectomy and yet higher risk of VVF. However, to our knowledge, large studies have not assessed the relationship between hysterectomy type, injury and VVF together in the same population. Knowing these relationships could aid the surgeon in choosing the route of surgery, could improve patient counseling, and could possibly encourage surgeons to use more caution when evaluating for intraoperative injuries after certain types of hysterectomies. We postulate that laparoscopy increases the risk of fistula repair, and that overall rates of VVF differ by type of hysterectomy. We designed a study to examine the complex relationships between urinary tract injury, type of hysterectomy and use of laparoscopy.

MATERIALS AND METHODS

We performed a retrospective cohort study utilizing the Healthcare Cost and Utilization Project (HCUP) databases, specifically the State Inpatient Databases (SID) and The State Ambulatory Surgery and Services Databases (SASD). HCUP includes the largest collection of longitudinal hospital care data in the United States, with all-payer, encounter-level information. Details regarding HCUP are described elsewhere [13]. The SID and SASD have supplemental revisit information, which allowed patient-level longitudinal tracking. We obtained SID, SASD, and associated supplemental revisit information for California, New York, and Florida from 2005–2011. We combined SID and SASD data to include all recorded hysterectomies in the selected states.

Hysterectomies were identified in women aged 18 and above. SID contains ICD-9 procedural codes, while SASD uses CPT codes; therefore, the combination of both databases was used to define hysterectomy, urinary tract repair, and fistula repair procedures (Appendix A). VVF repair codes were identified within 1 year after hysterectomy up to 2011. The Vanderbilt University Medical Center Institutional Review Board deemed this study to be exempt. The primary outcomes for this study were reported urinary tract injury during hysterectomy and subsequent repair of VVF.

We identified three main types of hysterectomy: 1) total abdominal hysterectomy, 2) subtotal abdominal hysterectomy and 3) vaginal hysterectomy. The hysterectomies were then further subtyped by laparoscopy use as follows: total abdominal hysterectomy (TAH- referent category), total laparoscopic hysterectomy (TLH), subtotal (supracervical) abdominal hysterectomy (SAH), laparoscopic subtotal (supracervical) hysterectomy (LSH), total vaginal hysterectomy (TVH) and laparoscopic-assisted vaginal hysterectomy (LAVH). We excluded hysterectomies performed for cancer or if a gynecologic cancer diagnostic code was noted within one month of the surgery (Appendix B). Procedures with unclear use of laparoscopy were excluded. Information on robotic assistance was not available, therefore robotic versus straight-stick laparoscopy cannot be delineated. Information regarding any previous radiotherapy and previous pelvic surgery were not available through the HCUP datasets. Participant characteristics are reported in Table 1.

Table 1.

Characteristics of eligible patients who underwent hysterectomy for benign gynecologic conditions from 2005 to 2011 in California, Florida and New York.

Characteristics	N	Mean (SD)
Age	581,395	47.8 (10.7)
	N	%
Race/ethnicity
White	345,263	59.39
Black	76,994	13.24
Hispanic	99,585	17.13
Asian or Pacific Islander	21,900	3.77
Native American	940	0.16
Other	36,713	6.31
Obesity
No	525,649	90.41
Yes	55,746	9.59
Diabetes
No	540,936	93.04
Yes	40,459	6.96
Hypertension
No	448,278	77.1
Yes	133,117	22.9
Insurance type
Private Insurance	422,910	93.87
Medicare	62,919	10.82
Medicaid	59,936	10.31
Self-pay	11,265	1.94
No charge	3,337	0.57
Other	20,793	3.58
Missing	235	0.04
Hysterectomy type
Total abdominal (open)	189,913	32.67
Total laparoscopic	36,763	6.32
Subtotal abdominal (open)	75,361	12.96
Subtotal laparoscopic	57,748	9.93
Total Vaginal	123,632	21.26
Laparoscopic-assisted Vaginal	97,978	16.85
Inpatient surgery
No	78,510	13.5
Yes	502,885	86.5
Year of surgery
2005	49,315	8.48
2006	62,770	10.8
2007	96,956	16.68
2008	94,451	16.25
2009	94,037	16.17
2010	91,984	15.82
2011	91,882	15.8
Urban Medical Center
No	38,486	6.62
Yes	542,271	93.27
Missing	638	6.96
State of Surgery
California	254,074	43.7
Florida	185,947	31.98
New York	141,374	24.32
Urinary tract injury
No injury	754,693	98.85
Bladder/ureter injury	6,702	1.15
Fistula
No	580,755	99.89
Yes	640	0.11

To evaluate all reported associations, we constructed a multivariable adjusted logistic regression model (base multivariable model), which includes age at procedure, diabetes, hypertension, obesity status, race, medical insurance type, state, urban location of medical center, inpatient vs. outpatient surgery, hysterectomy category (total, subtotal, and vaginal), and laparoscopy use (yes/no).

We evaluated the association between report of urinary tract injury and subsequent VVF repair using the base multivariable model. We then evaluated whether use of laparoscopy during hysterectomy modifies the association between injury and VVF by performing interaction analysis. To further understand which hysterectomy subtypes were associated with the greatest risk of VVF we present multivariable adjusted results for all six subtypes of hysterectomy using TAH as the referent procedure. To examine the independent contribution of hysterectomy type on VVF we performed the analysis 1) in all eligible hysterectomy patients including individuals for whom an injury was reported (while also adjusting for it) and 2) excluding individuals with injuries reported during hysterectomy.

To understand if laparoscopy was a risk factor for VVF, independent of the hysterectomy category and report of injury, we first evaluated the association between laparoscopic assistance and VVF using the base multivariable model. We then used models stratified by hysterectomy subtype to understand if the association between laparoscopy and VVF differed by hysterectomy subtype. To further evaluate whether this association is driven through reports of injury, we performed the same analyses excluding individuals for whom injury was reported during hysterectomy.

Finally, we evaluated which of the six hysterectomy types is associated with the highest risk for VVF repair, whether laparoscopy was an independent risk factor for VVF repair, and whether the association between laparoscopy and VVF repair differed by hysterectomy type in multivariable adjusted models. All formal interaction analyses were computed with the likelihood ratio test. All statistical analyses are performed using STATA 16.0 (College Station, TX) in accordance with reporting guidelines established by HCUP.

RESULTS

A total of 837,737 hysterectomies were performed between 2005 and 2011. After excluding 177,283 hysterectomies with insufficient information regarding laparoscopic use and 79,059 with malignancy, complete information was available on 581,395 individuals (Table 1). Average age of patients was 47.8 years and approximately 60% identified as white. Most procedures were performed inpatient (86.5%) and were paid for by private insurance (93.9%). Thirty-three percent of procedures utilized laparoscopic assistance (Table 1). Urinary tract injuries were reported in 1.15% of patients and VVF in 0.11%. Of those that had a post-hysterectomy fistula repair, 20.5% had an antecedent urinary tract injury at the time of the index hysterectomy, while among subjects with identified urinary tract injury, 2.0% had a fistula repair (Table 2).

Table 2:

Associations between urinary tract injury, fistula repair and laparoscopy use.

Operative Categories	N-Fistula	N-Control	Odds Ratio	95% CI	P-value for interaction
1 Recognized Injury Present
No	509	573,556	1.00	Ref
Yes	131	6,561	20.08	(16.50, 24.44)	NA
2 Laparoscopy
Non-Laparoscopic
No injury detected	354	382,972	1	Ref
Injury detected	90	5,033	17.12	(13.52, 21.68)
Laparoscopic
No injury detected	155	190,584	1	Ref
Injury detected	41	1,528	30.24	(21.21, 43.11)
					0.014

¹Reduced model: 1 Fistula formation was modeled as the dependent variable with injury (no/yes) as the dependent variable while adjusting for type of hysterectomy (total abdominal, sub-total abdominal and vaginal), laparoscopy (no/yes), age (continuous), race (white, black, Hispanic, Asian or Pacific Islander, Native American and Other), health insurance type (private, Medicare, Medicaid, self-pay, no charge, other), obesity status (no/yes), diabetes status (no/yes), year of surgery (2005–2011), inpatient surgery (no/yes), urban center (no/yes) and state of surgery (California, Florida, New York)

²Full model Interaction terms were included as product of categorical terms laparoscopy (no/yes) and injury (no/yes) along with variables listed in reduced models 1 and 2. Likelihood ratio was computed subtracting the reduced from the full.

N-individuals included in the multivariable adjusted models are fewer than 581,385 as data are missing for two covariates: health insurance type and urban center.

Report of injury to the urinary tract in any type of hysterectomy was associated with 20-fold increased odds of undergoing VVF (OR 20.64; 95% CI 16.98, 25.10) (Table 2). Compared to women without detected intraoperative injuries, those with detected injuries were 30-fold more likely to undergo VVF repair if their surgery involved laparoscopy but only 17-fold more likely if their surgery did not involve any use of laparoscopy (Table 2). We detected a statistically significant interaction between laparoscopy and injury in relation to VVF repair irrespective of hysterectomy type (p=0.014).

After detecting a statistical interaction between recognized injury and laparoscopy, we evaluated if laparoscopy alone was independently associated with undergoing fistula repair. In multivariable-adjusted models including injuries, women who had a procedure involving laparoscopy were 1.53 times (OR 1.53; 95% CI 1.26, 1.87) more likely to have a VVF repair than those without laparoscopy (Table 4). We repeated this assessment in individuals with no reported injury at the time of the hysterectomy and the OR remained positive (OR 1.40; 95% CI 1.12, 1.75) (Table 4).

Table 4.

Association between laparoscopy and fistula repair within each strata of hysterectomy type

	All individuals1				Excluding Injures2
Procedure Type	N-Fistula	N-Controls	OR	95% CI	N-Fistula	N-Controls	OR	95% CI
Any Laparoscopy
No	444	387,921	1.00	Ref	354	382,888	1.00	Ref
Yes	196	191,962	1.53	(1.26, 1.87)	155	190,434	1.40	(1.12, 1.75)
Hysterectomy type 3
Total Abdominal
TAH	378	189,280	1.00	Ref	300	186,434	1.00	Ref
TLH	57	36,667	0.94	(0.69, 1.29)	48	36,393	0.89	(0.63, 1.26)
Subtotal Abdominal
SAH	17	73,272	1.00	Ref	16	72,516	1.00	Ref
LSH	25	56,864	2.47	(1.25, 4.86)	20	56,577	1.84	(0.89, 3.78)
Total vaginal
TVH	49	121,605	1.00	Ref	38	120,219	1.00	Ref
LAVH	114	96,287	2.82	(1.98, 4.02)	87	95,339	2.79	(1.86, 4.19)

¹Reduced model: Fistula formation was modeled as the dependent variable with laparoscopy (no/yes) as the independent variable adjusted for hysterectomy type (total abdominal, sub-total abdominal, vaginal), injury (no/yes), age (continuous), obesity status (no/yes), diabetes status (no/yes), year of surgery (2005–2011), race (white, black, Hispanic, Asian or Pacific Islander, Native American and Other), health insurance type (private, Medicare, Medicaid, self-pay, no charge, other), inpatient surgery (no/yes), state of surgery (California, Florida, New York), and urban center (no/yes)

²Reduced model: Same model as 1 except reported injured are excluded and injury is removed from the model.

³Full model Interaction terms were included as product of categorical terms laparoscopy (no/yes) and hysterectomy type (total abdominal, sub-total abdominal, vaginal) along with variables listed in reduced models 1 and 2. Likelihood ratio was computed subtracting the reduced from the full.

We then evaluated the association between laparoscopy and VVF repair across hysterectomy categories (total, sub-total and vaginal) (Table 4). Laparoscopy was not uniformly associated with increased risk in all hysterectomy categories (p<0.001). Compared to those who had a TAH, TLH was not associated with increased risk of VVF repair in models including injury (OR 0.94) and excluding injury (OR 0.89). LSH was associated with 2.5-fold higher odds (OR 2.47; 95% CI 1.25, 4.86) of having VVF than SAH. The odds ratio was even higher for LAVH (OR 2.82; 95% CI 1.98, 4.02). Magnitudes of association were similar when excluding women with injury from analysis (Table 4).

To identify factors associated with fistula repair other than injury, we evaluated the association between types of hysterectomy procedures (Tables 3–4). In multivariable adjusted models including injury, compared to individuals having a TAH, those having had a SAH (OR 0.13; 95% CI 0.08, 0.22), LSH (OR 0.27; 95% CI 0.18, 0.32), TVH (OR 0.23; 95% CI 0.17, 0.32) and LAVH (OR 0.66; 95% CI 0.52, 0.83) had lower odds of having a fistula (Table 3). Re-evaluating this association limited to individuals without reported injuries did not change observed associations appreciably (Table 3).

Table 3.

Association between type of hysterectomy and fistula repair

	All Individuals1				Excluding Injuries2
Hysterectomy Type	N-Fistula	N-Controls	OR	95% CI	N-Fistula	N-Controls	OR	95% CI
TAH	378	189,280	1.00	Ref.	300	186,434	1.00	Ref.
TLH	57	36,667	0.95	(0.71, 1.28)	48	36,393	0.90	(0.65, 1.24)
SAH	17	75,244	0.13	(0.08, 0.22)	16	74,460	0.15	(0.09, 0.25)
LSH	25	57,606	0.27	(0.18, 0.32)	20	57,317	0.23	(0.15, 0.37)
TVH	49	123,397	0.23	(0.17, 0.32)	38	122,994	0.22	(0.15, 0.31)
LAVH	114	97,689	0.66	(0.52, 0.83)	87	96,724	0.59	(0.45, 0.76)

¹Fistula formation was modeled as the dependent variable with hysterectomy type as the independent variable (total abdominal [Ref], total abdominal laparoscopic, sub-total abdominal, sub-total abdominal laparoscopic, vaginal, vaginal laparoscopic) adjusted for injury (no/yes), age (continuous), race (white, black, Hispanic, Asian or Pacific Islander, Native American and Other), health insurance type (private, Medicare, Medicaid, self-pay, no charge, other), obesity status (no/yes), diabetes status (no/yes), year of surgery (2005–2011), inpatient surgery (no/yes), urban center (no/yes) and state of surgery (California, Florida, New York)

²Same model as 1 except reported injured are excluded and injury is removed from the model.

N-individuals included in the multivariable adjusted models are fewer than 581,385 as data are missing for two covariates: health insurance type and urban center.

Finally, we evaluated the risk of recording a urinary tract injury by hysterectomy types. In multivariable adjusted models, compared to TAH, all other surgical types were associated with reduced odds of injury, with lowest odds for LSH (OR 0.42; 95% CI 0.37, 0.48) (Table 5). Overall, the laparoscopic route was associated with lower odds of injury reports (OR 0.59; 95% CI 0.52, 0.67) than non-laparoscopic procedures. The association observed for laparoscopy and injury differed by hysterectomy category (p<0.001). TLH was less likely to have injury (OR 0.59; 95% CI 0.52, 0.68) than TAH, and injury was also less likely in LSH (OR 0.54; 95% CI 0.46, 0.63) than SAH. However, among those undergoing vaginal hysterectomy, LAVH had similar odds of injury as TVH (OR 0.98; 95% CI 0.90, 1.07).

Table 5.

Associations between types of hysterectomy, and laparoscopy use in relation injury detection.

Procedure Type	N-Injuries detected	N-No injury detected	OR	95% CI	P-int
Hysterectomy type
TAH	2,924	186,734	1.00	Ref
TLH	283	36,441	0.59	(0.52, 0.67)
SAH	785	74,476	0.74	(0.68, 0.80)
LSH	294	57,337	0.42	(0.37, 0.48)
TVH	1,414	122,032	0.84	(0.78, 0.90)
LAVH	992	96,811	0.81	(0.75, 0.87)
2 Any Laparoscopy
No	5,123	383,242	1.00	Ref
Yes	1,569	190,589	0.59	(0.52, 0.67)
Within strata comparisons
Total Abdominal
TAH	2,924	186,734	1.00	Ref
TLH	283	36,441	0.59	(0.52, 0.68)
Subtotal Abdominal
SAH	785	74,326	1.00	Ref
LSH	294	57,271	0.54	(0.46, 0.63)
Total Vaginal
TVH	1,414	122,032	1.00	Ref
LAVH	992	96,811	0.98	(0.90, 1.07)	<0.001

¹Injury was modeled as the dependent variable with hysterectomy type as the independent variable (total abdominal [Ref], total abdominal laparoscopic, sub-total abdominal, sub-total abdominal laparoscopic, vaginal, vaginal laparoscopic) age (continuous), race (white, black, Hispanic, Asian or Pacific Islander, Native American and Other), health insurance type (private, Medicare, Medicaid, self-pay, no charge, other), obesity status (no/yes), diabetes status (no/yes), year of surgery (2005–2011), inpatient surgery (no/yes), urban center (no/yes) and state of surgery (California, Florida, New York)

²Reduced model: Injury was modeled as the dependent variable with laparoscopy (no/yes) and as the independent variable adjusted for hysterectomy type (total abdominal, sub-total abdominal, vaginal), injury (no/yes), age (continuous), obesity status (no/yes), diabetes status (no/yes), year of surgery (2005–2011), inpatient surgery (no/yes), race (white, black, Hispanic, Asian or Pacific Islander, Native American and Other), health insurance type (private, Medicare, Medicaid, self-pay, no charge, other), state of surgery (California, Florida, New York), and urban center (no/yes)

DISCUSSION

Our study demonstrates the magnitude of association between laparoscopy and the need for subsequent VVF repair. It also highlights that association between injury and VVF repair varies by hysterectomy type. We confirm the association between injury identification at the time of hysterectomy and subsequent VVF repair, but also note approximately 80% of the VVF cases in our population were found in individuals in whom no injury was reported during hysterectomy.

A strength of our study is that the outcomes we assessed appear to be congruent with previously reported populations. The overall rate of urinary tract injury in our cohort is 1.2%. This concurs with a meta-analysis of 79 studies that reported the overall rate of urinary tract injury at the time of benign hysterectomy around 0.8% [14], and with a study based out of California that reported genitourinary tract injury to be about 1.8% (a subpopulation in our study) [8].

Another strength of our study is utilizing the HCUP database, which allowed us to conduct a large population-based study, representing different types of practices in multiple geographic regions in the United States, and capturing both inpatient and outpatient procedures. Our study was less dependent on return to the same facility, as any post-operative complications that were followed up in the same state as the original procedure was captured. Finally, the large number of urinary tract injuries and VVF events captured allowed us to assess relationships between hysterectomy type, injury and VVF in greater depth than previously published studies.

However, as with most administrative databases, there are inherent limitations. One such limit is that our data are dependent on the accuracy of the coding performed. Related to coding is the inability to further delineated types of laparoscopies. Since the use of robotic-assisted laparoscopy was poorly defined, we cannot apply our findings to a technology which is now being more commonly applied. We also must consider how the learning curve associated with the application of technology which was new at the time of our data collection affects the outcomes reported. There is also no standard definition of how much laparoscopy constitutes a laparoscopic-assisted case, so our findings cannot be broadly applied to all laparoscopies, particularly LAVH. Another limitation of our study is that we are unable to account for cases that were converted to a different approach, and instances where a conversion is necessary could increase the risk of intraoperative injury or fistula formation. Working within the scope of the dataset, we excluded individuals with recent diagnosis of cancer or gynecologic cancer, however information regarding past pelvic radiation, past pelvic surgery, or specific indication for the hysterectomy could not be obtained. Previous therapies or certain indications for surgery can significantly increase the risk of operative complications, and our findings should be considered in light of the possibility this could in part explain findings from this study if these factors were also associated with choice of route and type of hysterectomy. Furthermore, post-operative complications can also contribute to VVF formation, however, due to lack of this information, we are not able to assess the potential associations between hysterectomy choice and complications and the potential mediating role of these complications on VVF.

Our study improves the existing literature by quantifying our findings by subtype of hysterectomy. Three other studies have evaluated the relationship between hysterectomy type, genitourinary injury and fistula formation in large numbers [15,6,8]. Hesselman et. al reported a 15-fold increased risk of pelvic organ fistula formation associated with organ injury (OR = 15.3) and reported a higher risk of fistula formation associated with total abdominal (OR = 2.25) and laparoscopic hysterectomy (OR = 1.75) compared to vaginal hysterectomy (concomitant procedures not discussed) [15]. Although these findings are not directly comparable to our study, as they included vascular and bowel injuries in addition to urinary tract injuries and included all pelvic organ fistulas, some of our findings are in agreement, including the lower odds of VVF in TVH (OR = 0.22) and LAVH (OR = 0.66) compared with TAH [15]. In another study Forsgren et. al did not evaluate injury rates by hysterectomy subtype, but similar to our study, reported higher rate of fistula repair surgery (82.2 per 100,000 person-years) among patients undergoing laparoscopic hysterectomy (including TLH and LAVH) compared to abdominal (total 12.9, subtotal 1.59) and vaginal (9.18) surgery [6]. The third study by Dallas et. al, reported lower risk of injury associated with laparoscopy use (OR = 0.59) compared with total abdominal surgery. The authors also reported higher risk of fistula formation if injury was detected on the same day than if it was delayed in detection, however, did not evaluate the relationship between hysterectomy subtype and fistula formation [8].

With regards to urinary tract injury, in contrast to our findings, a 2015 Cochrane review showed increased association of bladder or ureteral injury (together but not separately) when doing hysterectomy laparoscopically compared to abdominally [16]. This Cochrane review included randomized controlled trials and the search for injuries/outcomes may have been more thorough for laparoscopic procedures in these settings than for surgeries performed in non-study settings. Findings from our study bridge these seemingly disparate findings. Since injury during surgery is suspected to be a main cause of post-operative fistula formation, our observation of lower rates of injury but higher rates of VVF repair suggests the injury rate may be higher than what is detected and reported for laparoscopic procedures, or that the detection is better for non-laparoscopic procedures in observational study/real world clinical settings. Our observation that most VVF repairs were in individuals without reported injury further supports this idea. We postulate the association between using laparoscopy and subsequent repair of fistula is possibly due to the nature of when laparoscopic assistance is employed. Typically, it is thought that laparoscopy can provide a helpful adjunct in cases with a large uterine size, endometriosis, presence of fibroids, presence of scar tissue, previous cesarean delivery, or other abdominal surgeries. These same factors increase the risk of urinary tract injury and make it difficult to detect injury. There could be confounding given the adoption rate of laparoscopic hysterectomy, varying surgical case numbers and time to achieve proficiency in laparoscopy, and evolution of surgical equipment.

This work informs how type of hysterectomy contributes to risk of fistula repair, how urinary tract injury at the time of hysterectomy contributes to that risk, and how laparoscopy can be variably associated with injury and subsequent fistula repair, depending on the subtypes of hysterectomy being performed. Future work would ideally compare the rates of injury and fistula repair between traditional laparoscopy and robotic-assisted laparoscopy, as well as try to incorporate relevant information regarding past surgical history pre-operative therapies, indications for benign hysterectomy, and other post-operative complications to assess the confounding and mediating effects of these factors on the associations between hysterectomy type, injury and fistula repair.