A propensity score analysis of outcome in retroperitoneal laparoscopic partial versus total adrenalectomy: a cohort study

Introduction

Adrenalectomy, the surgical removal of the adrenal gland, is a crucial procedure for managing various adrenal lesions, including benign and malignant tumors, hyperfunctioning glands, and incidentalomas (1,2). The advent of minimally invasive techniques, such as retroperitoneal laparoscopic adrenalectomy (RLA), has revolutionized adrenal surgery by reducing operative trauma, enhancing recovery times, and minimizing hospital stays (3,4).

Initially, laparoscopic adrenalectomy (LA) was celebrated for its success, but partial resections soon followed to address complex endocrine disorders (5,6). Laparoscopic total adrenalectomy (LTA), involving the complete removal of the adrenal gland, is traditionally favored for its definitive nature and reduced risk of recurrence. However, it carries the risk of adrenal insufficiency, necessitating lifelong hormone replacement therapy (7). Conversely, laparoscopic partial adrenalectomy (LPA) aims to preserve adrenal function and avoid the complications associated with hormone replacement, but concerns about the adequacy of tumor resection and potential for recurrence persist (8). There remains debate over whether LTA is necessary in all cases or if LPA is suitable for selected situations. Since then, many surgeons have adopted this approach, demonstrating the feasibility and safety of LPA (9). However, the short- and long-term outcomes of LPA remain controversial. Specifically, there are concerns regarding higher perioperative complication rates, the adequacy of residual adrenal function, the potential risk of tumor recurrence, and the challenge of balancing oncologic safety with functional adrenal preservation when compared to LTA (7,9-11).

Given that cortical adenomas and hyperplasia are among the most common benign adrenal pathologies, optimizing the surgical approach for these lesions is particularly important. This study aims to compare the short-term surgical outcomes of total vs. partial adrenalectomy in patients with adrenal cortical adenoma or adrenal hyperplasia, focusing on operative time, intraoperative blood loss, duration of postoperative drain placement, postoperative length of stay (LOS), and perioperative complications. This comparison holds clinical significance as it highlights the balance between preserving adrenal function and ensuring surgical completeness while minimizing the risks of recurrence and complications.

By employing propensity score matching (PSM) methods to mitigate selection bias and balance baseline characteristics, we seek to provide clearer insights into the relative benefits and risks of each surgical approach. This study’s findings will supplement existing knowledge regarding the surgical outcomes of LPA vs. LTA, offering guidance for clinical decision-making and enhancing surgical outcomes. We present this article in accordance with the STROBE reporting checklist (available at https://ales.amegroups.com/article/view/10.21037/ales-24-61/rc).

Methods

Study design

A retrospective review was conducted on the medical records of 569 consecutive patients who underwent RLA at the Department of Urology, Beijing Anzhen Hospital, Capital Medical University, between January 2012 and December 2021. Data collected included patient demographics (sex and age), surgical details (operative time), body mass index (BMI), American Society of Anesthesiologists (ASA) classification, surgeon experience (with the first 30 cases considered the learning phase), lesion side (left or right), type of adrenalectomy (partial or total), lesion size (longest diameter in centimeters), perioperative complications, and pre-existing comorbidities such as hypertension, diabetes, cardiovascular, and respiratory diseases.

The inclusion criteria were: (I) patients, diagnosed with an adrenal gland lesion have been scheduled for either LPA or LTA; (II) patients who underwent RLA exhibit pathological results indicating either adrenal cortical adenoma or adrenal hyperplasia. Exclusion criteria were: (I) patients underwent transperitoneal LA; (II) patients with a history of ipsilateral retroperitoneal surgery; (III) patients who received robot-assisted RLA.

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the ethics committee of Beijing Anzhen Hospital (No. 2025140x) and individual consent for this retrospective analysis was waived.

Surgical technique description

All patients underwent lateral retroperitoneal laparoscopic adrenalectomy (LRLA) following a standardized approach. After positioning the patient in the lateral decubitus position and flexing the operating table to optimize the retroperitoneal working space, trocars were placed through small incisions along the midaxillary, anterior axillary, and posterior axillary lines.

For both LPA and LTA, the adrenal gland was exposed by mobilizing the upper pole of the kidney. In LPA, only the tumor and a margin of surrounding adrenal tissue were carefully excised using an ultrasonic scalpel, with preservation of as much normal adrenal tissue as possible. In LTA, the entire adrenal gland was resected.

Outcome definition

The primary outcome was the incidence of perioperative complications occurring from the day of surgery to hospital discharge. Perioperative complications were categorized using the Clavien-Dindo classification system (12,13), with only those classified as grade 2 or higher included in this analysis. It is important to highlight that adrenocortical insufficiency was excluded from the Clavien-Dindo classification. The secondary outcomes included prolonged operative time, defined as durations exceeding 135 minutes (above the 75th percentile of the 569 RLA cases), and increased intraoperative blood loss, defined as amounts exceeding 30 mL (also above the 75th percentile of the 569 RLA cases).

PSM

To control for confounding factors, PSM was utilized in this study. The matching was performed using the “MatchIt” package in R software (version 4.4.1 for Mac) and employed the 1:1 nearest neighbor matching algorithm (method = “nearest”) without setting a caliper. This approach ensured that the demographics and comorbidities of the matched groups were more likely to be homogeneous. The covariates included in the PSM analysis to create balanced groups were as follows: sex, surgeon’s experience, age, BMI ≥25 kg/m², lesion laterality, pathology type of the lesions, preoperative comorbidities (hypertension, diabetes, and respiratory disease), lesion diameter, and ASA score.

Statistical analysis

Continuous variables with normal distributions were expressed as mean ± standard deviation, and comparisons between the LTA and LPA groups were performed using Student’s t-test. For non-normally distributed data, median and interquartile range (IQR) were reported, and the Wilcoxon rank-sum test was applied for comparisons. Categorical variables were analyzed using the Chi-squared test or Fisher’s exact test, as appropriate. Furthermore, univariate logistic regression analyses were conducted to evaluate the impact of partial and total adrenalectomy on prolonged operative time and increased intraoperative blood loss on the entire cohort. All statistical analyses were executed using R software (version 4.4.1 for Mac). A P value of <0.05 was deemed statistically significant.

Results

PSM

A total of 569 patients who underwent RLA for adrenal cortical adenoma and hyperplasia were recruited in this study. Of these patients, 423 (74.3%) underwent LPA and 146 (25.7%) underwent LTA, with a mean age of 52.3 years (range, 17–80 years), whose original baseline characteristics are demonstrated in Table 1. Overlooking potential confounding factors when comparing surgical outcomes between LPA and LTA groups may give rise to grievous bias in the analysis result. Therefore, we employed the PSM method to reduce biases and achieve a better balance in distributions of covariates between the two groups by compensating for differences among risk factors.

After PSM, 146 pairs of patients with balanced attributes are obtained. The clinical characteristics of these 292 patients are displayed in Table 2. There were no significant differences in sex, age, BMI, surgeon’s experience, ASA score, resection procedure, lesion laterality, lesion diameter, pathology type of the lesions and preoperative comorbidities between the two groups.

Comparison of surgical outcomes between LPA and LTA groups before matching

As shown in Table 3, the surgical outcomes of LPA and LTA were compared before matching. The median operative time was significantly longer in the LTA group compared to the LPA group: 120.00 [95.00, 150.00] vs. 100.00 [80.00, 135.00] min, P<0.001. Additionally, there was a statistically significant difference in the time to postoperative drainage tube removal between the LPA group and the LTA group: 3.00 [2.00, 4.00] vs. 3.00 [2.00, 3.00] days, P=0.02.

There were no statistically significant differences in intraoperative blood loss: 20.00 [10.00, 30.00] vs. 20.00 [10.00, 50.00] mL, P=0.056; postoperative LOS: 6.76±1.61 vs. 6.63±1.25 days, P=0.38; and the rates of postoperative complications between the LPA group and the LTA group (10.6% vs. 8.9%, P=0.55) (Table 3). These results are visualized using violin plots and a box plot (Figure 1).

Figure 1 An analysis of surgical outcomes for LPA and LTA groups before PSM, illustrated with violin and box plots. (A) Operative time; (B) intraoperative blood loss; (C) time to postoperative drainage tube removal; (D) postoperative length of stay. LPA, laparoscopic partial adrenalectomy; LTA, laparoscopic total adrenalectomy; PSM, propensity score matching.

Comparison of surgical outcomes between LPA and LTA groups after matching

As shown in Table 4, the surgical outcomes of the LPA and LTA groups were compared after matching. The mean postoperative LOS was significantly longer in LPA group compared to the LTA group: 7.00±1.77 vs. 6.63±1.25 days, P=0.04. Additionally, there was a statistically significant difference in the time to postoperative drainage tube removal between the LPA and LTA group: 3.00 (2.00, 4.00) vs. 3.00 (2.00, 3.00) days, P=0.003.

There were no statistically significant differences in operative time 107.50 [85.00, 135.00] vs. 120.00 [95.00, 150.00] min, P=0.08; intraoperative blood loss: 20.00 [10.00, 50.00] vs. 20.00 [10.00, 50.00] mL, P=0.51; and the incidence of postoperative complications between the partial adrenalectomy and total adrenalectomy group (9.6% vs. 8.9%, P=0.84) (Table 4). These results are visualized using raincloud plots and a box plot (Figure 2).

Figure 2 An analysis of surgical outcomes for LPA and LTA groups after PSM, illustrated with raincloud and violin plots. (A) Operative time; (B) intraoperative blood loss; (C) time to postoperative drainage tube removal; (D) postoperative length of stay. LPA, laparoscopic partial adrenalectomy; LTA, laparoscopic total adrenalectomy; PSM, propensity score matching.

Univariate and multivariable logistic regression analyses in the entire cohort

To explore the influence of partial vs. total adrenalectomy on surgical outcomes, univariate and multivariate logistic regression analyses were performed, using the 75th percentile as the cutoff to define prolonged operative time and increased intraoperative blood loss. Consequently, univariate logistic regression analysis demonstrated that LTA was associated with a prolonged operative time [odds ratio (OR): 1.98, 95% confidence interval (CI): 1.31–3.00, P=0.001]. However, this association was not statistically significant in the multivariate analysis (OR: 1.54, 95% CI: 0.98–2.41, P=0.06). The covariates included in the multivariate analysis were BMI, tumor diameter, gender, surgical experience, surgical approach, and pathology. In addition, univariate logistic regression analysis indicated that LTA was not significantly associated with increased intraoperative blood loss (OR: 0.70, 95% CI: 0.46–1.06, P=0.09).

Discussion

Partial adrenalectomy has been described for bilateral pheochromocytomas and is nowadays extensively used for this subgroup of patients to prevent lifelong substitution therapy (14,15). Additionally, it is applicable for excising small Conn’s adenomas, with some research indicating that it can achieve a similar cure rate to total adrenalectomy in certain cases (10,16). Furthermore, for cases of hypercortisolism related to macronodular bilateral hyperplasia, partial adrenalectomy can be recommended (17). Our study aimed to compare the surgical outcomes of LPA vs. LTA, focusing on operative time, drainage tube removal time, postoperative hospital stays and perioperative complications. The findings uncovered several important points that inform the ongoing debate about the optimal surgical strategy for adrenalectomy.

Firstly, our results indicate that although LPA was associated with a slight increase in the time to removal of postoperative drainage tubes and the length of postoperative hospital stay, these differences were minimal. However, we acknowledge that the clinical impact of these differences on overall patient recovery cannot be fully determined based solely on these parameters and requires further evaluation with specific recovery metrics. The slightly longer drainage tube removal time and hospital stay in the LPA group may reflect the need for closer monitoring of bleeding risk after partial adrenalectomy.

Additionally, there were no significant differences between LPA and LTA in terms of operative time, intraoperative blood loss, or postoperative complications. This finding suggests that, despite a slightly longer postoperative drainage duration and postoperative hospital stay, partial adrenalectomy can be as effective and safe as total adrenalectomy. This is crucial information for surgeons considering partial adrenalectomy as a viable option, especially in cases where adrenal-sparing surgery is desirable.

Our findings revealed that the LTA group experienced a longer median operative time than the LPA group. This finding supports the hypothesis that total adrenalectomy, which involves the complete removal of the adrenal gland, may be more technically challenging and time-consuming than partial adrenalectomy, which aims to preserve a portion of the gland. Furthermore, concerning the association between LTA and prolonged operative time observed in univariate analysis (OR: 1.98, P=0.001) but not reaching statistical significance in multivariate analysis (OR: 1.54, P=0.06), this suggests that other covariates—such as tumor size, tumor location, or surgeon-related factors—may have had an impact on operative time, thereby attenuating the direct effect of the surgical approach itself.

In terms of intraoperative blood loss, our study found no statistically significant difference between the LPA and LTA groups. Both univariate and multivariate analyses confirmed this result, suggesting that partial adrenalectomy does not inherently carry a higher risk of bleeding complications compared to total adrenalectomy. This finding is reassuring for surgeons, indicating that LPA can be performed without increased concern for intraoperative blood loss. The comparable blood loss between the two procedures underscores the safety and feasibility of LPA, offering a viable surgical option that does not compromise patient safety with respect to bleeding. Additionally, the absence of significant differences in postoperative complications, as assessed by the Clavien-Dindo classification, underscores the safety of partial adrenalectomy.

Previous studies have explored similar topics. A study involving 212 patients reported that while the operative time for partial adrenalectomy was shorter than for total adrenalectomy, this difference was not statistically significant. The study observed significantly higher intraoperative blood loss in the partial adrenalectomy group compared to the total adrenalectomy group (P<0.05); however, no patients in either group required blood transfusions (10). Additionally, a study involving 40 patients demonstrated that operative time, blood loss, and length of hospital stay were comparable between the total and partial adrenalectomy groups, with no significant perioperative or postoperative complications reported (7). Chen et al. achieved similar findings (18). The study also concluded that LPA is secure and feasible, yielding therapeutic results akin to LTA in patients with nonhereditary hormonally active unilateral adrenal masses.

These findings are consistent with our results, emphasizing the growing importance of minimally invasive and organ-sparing techniques (19,20). By preserving adrenal tissue, partial adrenalectomy may offer long-term benefits for maintaining endogenous adrenal function, which is particularly beneficial for patients with bilateral adrenal diseases or those at risk of adrenal insufficiency (17,21). Future research should focus on long-term outcomes and quality of life measures to further validate these benefits and confirm the role of partial adrenalectomy in the management of adrenal diseases.

Several studies emphasize the importance of long-term follow-up in evaluating adrenal function preservation and recurrence risk after adrenal surgery. Walz et al. (22) reported favorable long-term outcomes in patients undergoing partial adrenalectomy, with no local recurrence and preserved adrenocortical function in most bilateral cases. Similarly, Simforoosh et al. (21). found no significant differences in symptom resolution or recurrence between partial and total adrenalectomy after two years, with excellent outcomes in Cushing’s and Conn’s disease following partial resection. These findings provide further support for the oncological safety and functional benefits of adrenal-sparing surgery in selected cases, underlining the need for future prospective studies with longer follow-up to validate these results and determine optimal patient selection criteria.

The retrospective design, with its inherent risks of potential selection bias and lack of randomization, combined with the relatively small sample size, may limit the generalizability of our findings. Although PSM was applied to reduce bias and enhance comparability, residual confounding factors may still exist. Moreover, this study lacks long-term follow-up data, including outcomes related to adrenal function preservation and recurrence risk. To substantiate our findings and assess the long-term outcomes of partial vs. total adrenalectomy, future research with larger samples and extended follow-up is required.

Conclusions

In conclusion, our study provides evidence that partial RLA is a safe and effective alternative to total RLA, with comparable operative times, intraoperative blood loss, and postoperative complication rates. While partial adrenalectomy may involve a modest prolongation of postoperative care, including the removal of drainage tubes and an extended postoperative LOS, its advantages in preserving adrenal function make it a valuable option in selected cases. Surgeons should consider individual patient factors and preferences when deciding between partial and total adrenalectomy, and further research is needed to refine the indications and techniques for partial adrenalectomy.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://ales.amegroups.com/article/view/10.21037/ales-24-61/rc

Data Sharing Statement: Available at https://ales.amegroups.com/article/view/10.21037/ales-24-61/dss

Peer Review File: Available at https://ales.amegroups.com/article/view/10.21037/ales-24-61/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ales.amegroups.com/article/view/10.21037/ales-24-61/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the ethics committee of Beijing Anzhen Hospital (No. 2025140x) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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