Incisional Hernia Development after Live Donor Nephrectomy: Impact of Surgical Technique

Abstract

Key Points

• The incidence of incisional hernia (IH) after live donor nephrectomy (LDN) is prevalent and associated with obesity and operative technique.

• Placing the hand port infraumbilical with a transverse fascial incision may reduce the risk of IH after LDN.

Background

Characteristics of incisional hernia (IH) formation after live donor nephrectomy (LDN) are not well-defined. The goal of this study was to describe the incidence of IH within 3 years after LDN and identify risk factors contributing to their formation.

Methods

We performed a single-center, retrospective review of all LDN between February 2013 and October 2018. Patients with and without IH were compared based on donor and operative variables. Data were analyzed using chi-square tests with column proportions. Multivariable logistic regression with backward elimination was used to evaluate the likelihood of IH on the basis of potential risk factors.

Results

Three hundred one individuals underwent live donor nephrectomy. Twenty-eight patients (9.3%) developed an IH, with a median time to development of 7 months (range: 2–24 months). Obesity (body mass index ≥30), periumbilical hand port, and vertical infraumbilical hand port were associated with increased risk of IH development on univariate analysis. On multivariate analysis, obesity and periumbilical hand port location were persistent risk factors for IH.

Conclusions

The incidence of IH after LDN is prevalent and associated with obesity and operative technique. Placing the hand port infraumbilical with a transverse fascial incision may reduce the risk of IH after LDN.

Introduction

Kidney transplantation is the optimal treatment for most causes of ESKD. As the outcomes of transplantation improve, the demand for kidney transplant continues to increase. While there are over 100,000 people waiting for a kidney, only 24,273 individuals received kidney transplants in 2019.¹ A steady increase in the number of living kidney donors since 2017 has been a positive trend allowing more recipients to receive high-quality organs.¹ The clinical benefits of kidney transplantation from a living donor compared with a deceased donor are substantial and include improved patient and graft survival, improved quality of life, and reduction in time to transplant.^2–4

While improved recipient outcomes are apparent with living kidney donation, the health and safety of the donor are paramount. Living donors are healthy individuals who receive no direct benefit from the procedure; therefore, a high standard of safety must be maintained. Surgical approaches to live kidney donation have evolved since its inception with laparoscopic approaches largely replacing the traditional open flank incision.^5–7 Reasons for this transition include studies demonstrating that laparoscopic techniques speed recovery and improve quality of life after donation compared with open techniques.^8–11 Despite these advantages, laparoscopic approaches are still subject to other common surgical complications.

Hernias have the potential to develop after any type of abdominal incision. With an overall incidence of 4%–15%, incisional hernia (IH) represents a significant source of morbidity to those undergoing elective abdominal surgery.^12–14 Although laparoscopic approaches have minimized the invasiveness of live donor nephrectomy, hernias still have the potential to develop from port sites and kidney extraction incisions. Single-center studies have shown that the incidence of IH after LDN is between 0% and 4%.^15–17 The characteristics of IH after LDN, including risk factors for their formation, are less clear. The goal of this study is to describe the incidence of IH within 3 years of LDN at our center and identify potential risk factors contributing to IH formation.

Materials and Methods

Study Design

This investigation is a single-center retrospective review of a prospectively maintained clinical database performed after Institutional Review Board approval. We included consecutive adult individuals who donated a kidney at Vanderbilt University Medical Center from February 2013 to October 2018, thus allowing for all persons to have at least 3 years of surveillance for IH at the time of the December 2021 data analysis. Our cohort of living donors was divided into two groups on the basis of IH development and compared on multiple patient and clinical variables to identify potential risk factors for development of IH within 3 years after LDN.

Operative Approach

Over the 5-year study period, our approach to LDN remained relatively constant. A left donor nephrectomy would routinely be performed laparoscopic with a hand-assisted technique. Positioning of the hand port varied over the study period. Most notably, it was either periumbilical or infraumbilical. Fascial incisions for infraumbilical hand ports were oriented either vertically or transversely. All incisions for periumbilical hand ports were oriented vertically. Fascial closure was routinely performed using 2-0 polydioxanone suture in a running fashion. The technique followed a conventional approach with 1-cm bites of tissue for every 1 cm of tissue length. Right kidneys were routinely approached retroperitoneally through a subcostal incision centered over the 11th rib.

Data Collection

Prospective data maintained on all living donors included demographic information, organ specific data, and 3-year clinical outcomes. Retrospective chart review for each donor was used to capture additional clinical variables including donor body mass index (BMI), prior smoking, prior abdominal surgery, surgical approach, and hand port location. Characteristics of hernia development included time from donation, urgency at diagnosis, treatment, mesh utilization, and recurrence. Criteria for diagnosing IHs were variable and included physical exam and cross-sectional imaging.

Statistical Methods

The primary outcome was occurrence of IH within 3 years of donation. Data were analyzed using summary statistics and chi-square tests with post hoc tests of column proportions (if indicated). Multivariable logistic regression with backward elimination was used to evaluate the effects of donor variables (gender, BMI category [normal/underweight, overweight, obese], prior smoking, prior abdominal surgery) and operative variables (whether laparoscopic and which kidney was donated) on the likelihood of IH within 3 years. A secondary multivariable analysis examined, among the laparoscopic procedures, the effect of donor and operative variables (kidney donated and whether a periumbilical versus infraumbilical incision was used). The chi-square test was used to evaluate, among persons having infraumbilical hand port procedures, whether a vertical or transverse incision was associated with IH within 3 years.

Results

Baseline Patient Characteristics

From February 2013 to October 2018, 301 individuals underwent LDN (Table 1). Two hundred seven (69%) of donors were female. The mean age at time of donation was 40±11.7 years. The mean BMI was 27.3±4.4. Of these donors, 32% were prior smokers while 41% had a history of prior abdominal surgery.

Table 1.

Summary data and univariate tests

Variable	With IH (n=28)a	Without IH (n=273)a	P Value	Total (n=301)a
Donor variables
Female	16 (57.1)	191 (70.0)	0.199	207 (68.8)
BMI			<0.001
Normal (18.5–24.9) or underweightb	4 (14.3)	99 (36.3)c		103 (34.2)
Overweight (25.0–29.9)	7 (25.0)	106 (38.8)		113 (37.5)
Obese (≥30.0)	17 (60.7)	68 (24.9)c		85 (28.2)
Prior smoking	10 (35.7)	88 (32.2)	0.679	98 (32.6)
Prior abdominal surgery	13 (46.4)	110 (40.3)	0.550	123 (40.9)
Operative variables
Laparoscopic	28 (100)	260 (95.2)	0.489	288 (95.7)
Left kidney donated	28 (100)	255 (93.4)	0.326	283 (94.0)
Subgroup analyses
Periumbilical hand portd	22 (78.6)	130 (50.0)	0.005	152 (52.8)
Infraumbilical vertical hand porte	6 (100)	52 (40.0)	0.013	58 (42.6)

Table entries are frequency (column %). Data refer to whether IH developed within 3 years of donation. IH, incisional hernia; BMI, body mass index.

^aSample sizes for overall analyses (excluding subgroup analyses).

^bIncludes two underweight donors (with BMI 16.6 and 18.4).

^cColumn proportions differ (P<0.05).

^dAmong laparoscopic: n=288; 28 with IH, 260 without IH (ref: infraumbilical).

^eAmong infraumbilical laparoscopic: n=136; 6 with IH, 130 without IH (ref: infraumbilical transverse).

Operative Variables

The left kidney was procured in 283 of 301 (94%) cases. Two hundred eighty-eight cases (96%) were performed laparoscopically with the hand-assisted technique. A periumbilical hand port was used in 152 cases, whereas 136 were performed through an infraumbilical hand port. Infraumbilical hand ports were placed through either a vertical (58) or transverse (78) fascial incision.

Incisional Hernia

A total of 28 patients developed IH within 3 years of donation. The median time to diagnosis was 7 months (range: 2–24 months). The majority of IH were managed surgically in elective fashion. Urgent surgical intervention was required in two cases. Mesh was used for repair in most cases with only two undergoing primary repair. Recurrence of IH was identified in two patients.

Risk Factor Analysis

The study cohort (n=301) included 28 persons (9%) who developed IH within 3 years and 273 (91%) who did not (Table 1). Univariate analyses demonstrated that BMI category was the only donor variable associated with IH development (P <0.001). Sixty-one percent of IH patients were obese versus 25% without IH (P <0.05). Conversely, 36% of persons without IH and 14% of those with IH were normal/underweight (BMI ≤24.9; P <0.05). There was no difference in the proportions of persons with and without IH who were overweight (BMI 25.0–29.9). Multivariable models in the total sample (Table 2) reflected this finding in that obese donors were, on average, 6 times more likely to develop IH within 3 years compared with normal or underweight donors (odds ratio [OR], 6.19; 95% confidence interval [CI], 2.00 to 19.19). Gender, prior smoking or abdominal surgery, laparoscopic (versus open) procedure, and whether the left or right kidney was donated were not associated with IH. Operative variables were, however, found to be associated with IH in subgroup analyses (Tables 1 and 3). Among the 288 laparoscopic procedures, compared with an infraumbilical hand port, the periumbilical hand port was associated with an over three-fold increased the likelihood of IH within 3 years (Table 3; OR, 3.70; 95% CI, 1.42 to 9.64). Among those procedures where infraumbilical hand ports were used (n=136), six persons (4%) developed an IH within 3 years and all six (100%) had vertical facial incisions. Alternatively, 6 of the 58 with vertical incisions (10%) developed IH and none of the 78 persons with transverse incisions developed IH. While the statistical comparison of the proportions is preliminary in this sample, these data suggest that, when the infraumbilical hand port is used, vertical incisions may be associated with an increase rate of IH over 3 years compared with transverse incisions (Table 1; P = 0.013).

Table 2.

Overall likelihood of incisional hernia (n=301)

Variable	B	P Value	OR	95% CI of OR
Starting model (P = 0.002; R 2 =0.155)
Female (ref: male)	−0.84	0.077	0.43	0.17 to 1.09
BMI		<0.001
Overweight (ref: nl/underweight)	0.41	0.524	1.51	0.42 to 5.40
Obese (ref: nl/underweight)	1.83	0.002	6.23	1.97 to 19.64
Prior smoking	0.25	0.572	1.28	0.55 to 3.00
Prior abdominal surgery	0.56	0.235	1.74	0.70 to 4.36
Laparoscopic approach	−0.49	1.000	0.61	0.00 to NA
Left kidney donated	19.36	0.999	>255 × 106	0.00 to NA
Constant	−21.78	0.998	0.00
Final model (P <0.001; R 2 =0.105)
BMI		<0.001
Overweight (ref: nl/underweight)	0.49	0.444	1.63	0.46 to 5.75
Obese (ref: nl/underweight)	1.82	0.002	6.19	2.00 to 19.19
Constant	−3.21	<0.001	0.04

OR, odds ratio; CI, confidence interval; BMI, body mass index.

Table 3.

Likelihood of incisional hernia in the laparoscopic sample (n=288)

Variable	B	P Value	OR	95% CI of OR
Starting model (P <0.001; R 2 =0.190)
Female (ref: male)	−0.82	0.095	0.44	0.17 to 1.15
BMI		<0.001
Overweight (ref: nl/underweight)	0.28	0.672	1.32	0.37 to 4.78
Obese (ref: nl/underweight)	1.76	0.003	5.80	1.81 to 18.55
Prior smoking	0.08	0.852	1.09	0.45 to 2.60
Prior abdominal surgery	0.66	0.178	1.93	0.74 to 5.00
Periumbilical hand port incision	1.25	0.012	3.49	1.31 to 9.28
Left kidney donated	18.52	0.999	>110 × 106	0.00 to NA
Constant	−22.18	0.999	0.00
Final model (P <0.001; R 2 =0.164)
BMI		0.001
Overweight (ref: nl/underweight)	0.35	0.587	1.42	0.40 to 5.07
Obese (ref: nl/underweight)	1.76	0.003	5.82	1.85 to 18.35
Periumbilical hand port incision	1.31	0.007	3.70	1.42 to 9.64
Constant	−3.94	<0.001	0.02

OR, odds ratio; CI, confidence interval; BMI, body mass index.

Discussion

This study is one of the first to fully describe the nature of IH after LDN and examine potential risk factors contributing to their formation. The results indicate that IH after LDN is prevalent and can have serious consequences. The reasons for their formation are multifactorial including both donor and operative variables. While donor smoking and prior abdominal surgery did not predispose individuals to IH after LDN, obesity was found to be a significant risk factor contributing to IH after LDN. Obesity has previously been implicated in the development of IH in other surgical settings^18–20; however, its role in IH after LDN has been less clear. While some studies suggest there is no difference in IH rates between obese and nonobese donors,²¹ others point toward obesity as a risk factor.²² Our study provides further evidence that obesity is an independent risk factor contributing to IH formation after LDN, specifically in donors with a BMI of >30. This information will be helpful in counseling those interested in donation who may be at additional risk for IH formation due to obesity.

In addition to donor factors, operative variables were found to have an important role contributing to the formation of IH after LDN. The location of the kidney extraction is an important consideration that varies across different techniques of LDN. While pure laparoscopic and robotic LDN techniques use a Pfannenstiel extraction site,^15,16 most hand-assisted techniques use a midline incision for kidney extraction.¹⁷ Pfannenstiel incisions have some of the lowest reported abdominal wall hernia rates in other minimally invasive settings and may also have cosmetic advantages compared with midline incisions.^23–25 Adding to the transplant literature, our study also demonstrates higher hernia rates from midline incisions compared with Pfannenstiel incisions after LDN, particularly periumbilical midline incisions. Our lowest hernia rates were in patients who had an infraumbilical hand port through a transverse incision, which is essentially a Pfannenstiel incision. Comparing multiple incision types within the same study strengthens our conclusion that the location of the kidney extraction site is a key determinant in the development of IH after LDN. As LDN continues to evolve, techniques that use a Pfannenstiel incision for the kidney extraction site will be well-positioned to mitigate the risk of IH development and enhance cosmesis.

There are limitations to our study. First, the study was conducted at a single-center using retrospective data. Patients were not prospectively randomized, which limits causal inference. In addition, sample size limitations precluded our being able to test the effect of the vertical versus transverse incision in the context of a multivariable model of persons having infraumbilical hand port procedures. Some of the impact of the infraumbilical orientation of the fascial incision may be associated with unidentified variables. We also recognize that our hernia rates were higher than previously reported in the literature.^15–17 There are a few reasons that may account for this finding. First, as previously stated, most hand-assisted techniques have higher hernia rates than pure laparoscopic or robotic techniques owing to the location of the kidney extraction site. Next, our patient population had a higher mean BMI than previously reported. Given our findings that obesity is an independent risk factor for IH after LDN, it is not surprising that our series has a higher IH rate than previously reported. Finally, all donors in our series had at least 3 years of follow-up, which allowed for late IH detection. Given the wide range of time to IH diagnosis (2–24 months), this is an important illustration that IH after LDN is not necessarily limited to the short term.

As the organ shortage crisis continues to worsen, living kidney donation will have an increasingly important role to help reduce the gap between organ supply and demand. Individuals willing to come forward and donate will need to be well informed of the potential risks to their health. Our study will help shape conversations surrounding the factors that affect IH formation after LDN. Obese populations will need preoperative counseling regarding their increased risk of IH after LDN compared with normal weight donors. Strategies that focus on preoperative weight loss will need to be considered to help mitigate the risk of IH after LDN in obese populations. Surgeons will need to consider best practices to reduce IH after LDN. Our results suggest that periumbilical hand ports have an increased risk of hernia formation compared with infraumbilical hand ports. The goal of future investigation will be to collect randomized prospective data comparing various surgical approaches to hand port location, specifically infraumbilical vertical compared with transverse facial incisions. We hope future investigations will help determine which technical factors contribute to IH development after LDN to minimize morbidity for future donors.

Disclosures

R.C. Forbes reports the following: Advisory or Leadership Role: Monogram Health (paid travel and consulting fee, 2 per year) since 2022. D.A. Hale reports the following: Consultancy: Novartis; Allovir. D. Shaffer reports the following: Ownership Interest: APA Corp, Apple, AT&T, Chevron, Duke Energy Corp, Intel, Microsoft, NexEra Energy, Procter & Gamble, Starbucks, State Street Corp, Verizon, Visa, and Walt Disney; and Advisory or Leadership Role: Monogram Health Clinical Advisory Board. The remaining authors have nothing to disclose.

Funding

None.

Author Contributions

B.J. DuBray, I.D. Feurer, R.C. Forbes, D.A. Hale, J.J. Tompson, and D. Shaffer conceptualized the study; B.J. DuBray, R.C. Forbes, D.A. Hale, and J.J. Tompson were responsible for data curation and investigation; B.J. DuBray was responsible for project administration; I.D. Feurer and S.A. Rega were responsible for formal analysis and methodology; B.J. DuBray, I.D. Feurer, R.C. Forbes, and S.A. Rega wrote the original draft; and B.J. DuBray, I.D. Feurer, R.C. Forbes, S.A. Rega, and D. Shaffer reviewed and edited the manuscript.

Data Availability Statement

The data used to support the findings of this study are available from the corresponding author upon request.