Introduction

Adrenal tumors are a significant clinical problem due to their potential to become malignant and cause severe hormonal imbalances (1). Laparoscopic adrenalectomy (LA) is a surgical technique to address adrenal tumors and has gained popularity because of its benefits, including decreased bleeding, lower risk of complications, less post-operative pain, shorter hospital stays, and improved scarring compared with open surgery (2, 3). LA can be used to remove various adrenal tumors, including functional and non-functional lesions (4). LA is a specialized surgery, best performed where it is frequently conducted. The European Society of Endocrine Surgeons states that centers performing at least six such surgeries annually are considered high-volume. Patients tended to have better results in these centers, likely because of experienced surgeons and resources that provide optimal care (5).
Although LA is minimally invasive and offers reduced recovery times and complication rates, it has traditionally been limited to smaller adrenal tumors. This is because of the feasibility and safety concerns of performing LA on larger tumors. However, this may prevent patients with larger tumors from benefiting from minimally invasive surgery. Currently, comprehensive studies evaluating the outcomes of LA for adrenal tumors of all sizes are lacking (6).
As surgeons gain experience, they may progressively expand the scope of laparoscopic indications to include larger and more complex adrenal tumors. This study examined how surgical expertise, measured over a 10-year period, influenced outcomes, complication rates, and tumor size inclusion in LA.

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Materials and Methods

The article adheres to the STROBE reporting guidelines. A retrospective observational study was conducted at the hospital affiliated with the College of Medicine at the University (approval number: 45). Written informed consent was obtained from all participants. Since this article does not contain any patient-identifying information, consent to publish was not required to be obtained from the patients. The analysis examined 100 LAs performed between February 2010 and December 2021.
Preoperatively, all patients went through a comprehensive clinical examination that included a detailed medical history, hormone tests to evaluate adrenal gland function, and diagnostic tests such as serum aldosterone, serum-free metanephrines, serum cortisol, low-dose dexamethasone suppression test, serum corticotrophin, 24-hour urinary metanephrines, and 24-hour urine cortisol. Imaging studies such as abdominal sonography and abdominal magnetic resonance imaging. Abdominal computed tomography was also conducted.
The inclusion criteria for LA during the initial assessment included hormonally active tumors measuring <80 mm in size, non-functioning benign tumors ranging from 40 to 80 mm with specific characteristics, and adrenal metastases <80 mm in size when the primary tumor was well-controlled. For tumors <4 cm and non-functioning benign tumors, regular follow-up was recommended. Surgery was only recommended if there was an increase in size or a change in function. With increasing surgical expertise and confidence in technique, tumors >8 cm were also considered for laparoscopic resection, particularly toward the end of the study period.
The study excluded 20 patients with large tumors (>15 cm) or primary malignant tumors with radiological or pathological evidence of local invasion or distant metastasis, those requiring reoperation for recurrent tumors, and those with multiple previous abdominal surgery scars. Surgeon expertise was assessed indirectly based on case order and time progression over the 12-year period. The same primary surgeon and team performed all operations, ensuring consistency in technique and progressive skill development. The lateral transperitoneal approach was used in all procedures.
Patient age, sex, tumor location and dimensions, histopathology, hormonal activity, surgical complications, and outcomes—including the need for conversion to open surgery, operation time, hospital stay, reoperation, and mortality—were collected.
Operative blood loss was estimated intraoperatively by measuring suction canister volume and subtracting irrigation fluid, and by accounting for surgical gauze saturation. Tumor size was determined using histopathological data, and the time required for the surgical procedure—from incision to closure—was recorded. The analysis of operating time did not include patients who underwent additional elective surgeries, conversion to open surgery, or bilateral procedures.
Patients with pheochromocytoma were administered specific medications such as alpha-adrenergic and beta-1 adrenergic receptor blockers and intravenous fluids to lower blood pressure, regulate heart rate, and increase blood volume. Medication management aimed to lower blood pressure to a safe level, set below 150/90 mmHg.

Operative technique
Laparoscopic left adrenalectomy
Patients were positioned laterally with their left side up, and the operating table was slightly flexed at the belly. The surgeon and the camera were placed on the right side of the patients. A Veress needle was inserted at the midpoint between the umbilicus and left costal margin at the mid-clavicular line, and carbon dioxide was insufflated to 13 mmHg. An optical 10-mm trocar was inserted at the site of the Veress needle insufflation, and another 10-mm port was inserted at the posterior axillary line. An additional 5-mm trocar was also placed. The left flexure of the colon was mobilized using a 5-mm  LigaSure™ (Medtronic, USA).coagulation handle, which was placed lateral to the xiphisternum, 3 cm below the costal margin. This was achieved by dividing the splenocolic and splenorenal ligaments and the posterior peritoneal attachment of the spleen up to the diaphragm. The left kidney and medial side of the adrenal gland were dissected to identify the left renal vein.
Through a precise dissection to isolate and clip the left adrenal vein, the adrenal gland was dissected from its attachment to the undersurface of the pancreas and posterior attachment to the diaphragm, avoiding injury to the pancreatic tail. The lateral surface of the adrenal gland was also dissected and divided to achieve complete separation. The specimen was extracted intact using an Endo retrieval bag. No piecemeal extraction was required, and the incision was minimally widened as required. Hemostasis was secured. A silicon-fenestrated Jackson-Pratt  drain was placed, and the skin incisions were sutured (Figure 1a and b).

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Figure 1a and b

(a) Left laparoscopic adrenalectomy port site marks. (b) Left laparoscopic adrenalectomy port site.

Laparoscopic right adrenalectomy
Patients were positioned laterally with their left side up, and the operating table was slightly flexed at the belly. The surgeon and assistant were on opposite sides of the patient. A Veress needle was inserted at the midpoint between the umbilicus and left costal margin at the mid-clavicular line, and carbon dioxide was insufflated to 13 mmHg. An optical 10-mm trocar was inserted at the site of the Veress needle insufflation point. The other two ports were inserted in the same position as described above for the left adrenalectomy, with the addition of a fourth 5-mm port just below the xiphisternum used for liver retraction.
A 5-mm LigaSure™ (Medtronic, USA).dissecting handle was used to divide the peritoneum 1 cm below the liver laterally up to the triangular ligament. The lateral attachment of the duodenum was dissected and mobilized to expose the inferior vena cava (IVC). Dissection in the plane between the IVC and the right adrenal gland medial and upward was performed to identify the main adrenal vein, which was meticulously dissected, clipped, and divided. This step was performed carefully to avoid excessive bleeding from the IVC. The dissection of the adrenal gland was performed in a similar manner to the left adrenalectomy. The specimen was extracted intact using an EndoRetrieval bag. No piecemeal extraction was required, and the incision was minimally widened as required. After carefully checking for hemostasis, the skin incisions were sutured (Figures 1c and d and 2).

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Figures 1c and d

(c) Right laparoscopic adrenalectomy port site marks. (d) Right laparoscopic adrenalectomy port site.

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Figure 2

Laparoscopic adrenalectomy

Laparoscopic bilateral adrenalectomy
When performing a laparoscopic bilateral adrenalectomy, it is customary to operate on patients diagnosed with Cushing’s syndrome or bilateral pheochromocytoma. The surgeon initiated the procedure by removing the left adrenal gland. After completing the left side, the trocar sites were sealed, and the right side was addressed. Blood pressure was closely monitored during the procedure. Nitroglycerin, a vasodilator, and short-acting beta-blockers may be used to treat intraoperative hypertension. If necessary, a brief stoppage of tumor dissection, abdominal desufflation, or both may be performed. The nitroglycerin infusion is stopped once the ligation and division of the adrenal vein are accomplished, and inotropes are given as required. Post-operatively, patients with functioning adrenal tumors are admitted to the surgical critical care unit for surveillance. Analgesics and antihypertensives were administered as needed, and vital signs, particularly blood pressure, were regularly checked. Data on the length of hospital stay, expected blood loss, and surgical time were collected, and post-operative problems were thoroughly evaluated.

Data analysis
Data were analyzed using SPSS version 27 (IBM, Chicago, IL, USA). Quantitative continuous variables were reported as means and standard deviations, while categorical variables were presented as frequencies and percentages. Independent t-tests were used to compare continuous variables across the two time periods (2010–2015 vs. 2016–2021). The chi-square test was used to assess associations between categorical variables. A p-value <0.05 was considered statistically significant.
Two multiple linear regression analyses were conducted to evaluate the associations among independent variables (age, sex, body mass index, presence of chronic disease, tumor size, and year of operation) and two continuous outcome variables (hospitalization days and operation time). The year of operation was treated as a continuous variable (ranging from 1.0 to 12.0, corresponding to 2010 through 2021). This study utilized a retrospective observational design. All analyses were performed by the primary author.Ethical approval was obtained from the Institutional Review Board of Baghdad Teaching Hospital, College of Medicine, University of Baghdad (Approval No. 45). The requirement for individual informed consent was waived due to the retrospective design of the study.

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Results

Overall, 100 patients who underwent LA for various reasons were included. Table 1 shows the clinicodemographic characteristics of the patients.

 

Table 1.

Clinicodemographic characteristics of patients undergoing laparoscopic adrenalectomy
Data are presented as a range and mean.
BMI, body mass index.

The analysis revealed notable findings regarding tumor characteristics, including preoperative biochemical and radiological tumor diagnoses (Table 2). Tumors were predominantly located on the left (54%) and the right (44%) sides; very few were bilateral (2%). The tumors varied in size from 3 to 12 cm, with an average size of 5.26 cm.

 

Table 2.

Preoperative biochemical, radiological, and histopathological characteristics of adrenal tumors
Data are presented as number and percentage, or range and mean.

 

Table 3.

Intraoperative and post-operative surgical characteristics and complications in laparoscopic adrenalectomy

Patient surgical characteristics were diverse, as outlined in Table 3. Surgical duration ranged from 15 to 180 minutes (mean: 55 minutes). Estimated intraoperative blood loss was recorded by the operating surgeon using suction measurements and surgical gauze weight, ranging from 10 to 1000 mL (mean: 105 mL). Post-operative histopathological diagnosis revealed several findings. Non-secreting adenomas were the most common, accounting for 36 patients, followed by pheochromocytoma in 31 patients. Cortisol-secreting adenomas were less common, accounting for only eight patients. These findings differed from preoperative diagnoses, where adrenal carcinoma was suspected in one patient, while post-operative diagnosis confirmed four cases of carcinoma.
Two patients (2%) required conversion to open surgery. The reasons for conversion included dense adhesions in one case and uncontrolled bleeding in the other. Complications during surgery included hypertensive crisis in seven patients (7%), hypotensive crisis in five (5%), and intraoperative bleeding in five (5%). Solid organ injuries such as splenic injury and right renal capsule tear occurred in isolated cases. Post-operative complications included bleeding (1%), respiratory issues (2%), hypotension (3%), incisional hernias (5%), and port site infections (4%). Additionally, concomitant procedures were performed in some cases, including cholecystectomy (3%) and hernia repair (5%). After undergoing LA, the average hospital stay was 3 days. The readmission rate within 30 days was 5%, highlighting the complexity and variability of outcomes.

 

Table 4.

Comparison of operative parameters and outcomes between the first and second 5-year periods of laparoscopic adrenalectomy cases
p-value calculated using the chi-square test; p < 0.05 considered statistically significant.

The comparison between the first and last 5 years in terms of various parameters revealed several significant findings (Table 4). There was a notable increase in the number of patients in the second group, comprising 58 patients, compared to 42 in the first group.
There was a significant decrease in the mean operative time from 73 minutes in 2010–2015 to 41 minutes in 2016–2021 (p = 0.005), suggesting improved surgical efficiency over time. The conversion rate remained low and comparable (1% in both groups, p = 0.07).
Intraoperative complications decreased significantly from 13 in the earlier group to 7 in the latter group (p = 0.004), indicating enhanced surgical safety. Post-operative complications showed a non-significant decline (9 vs. 6 cases, p = 0.06), and readmission rates were also similar (3 vs. 2 cases, p = 0.07).
According to the multivariate regression analysis, only the year of operation showed a statistically significant association with the two outcome measures (hospitalization days and operation time). More specifically, surgeries performed in more recent years were associated with significantly shorter hospitalization and operative durations after adjusting for confounders (p < 0.05) (Tables 5 and 6).

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Table 5.

Multiple linear regression analysis of patient characteristics and hospitalization days
Dependent variable: hospital stay (day). R2 = 0.24.
BMI, body mass index.
 

Table 6.

Multiple linear regression analysis of patient-related factors associated with operative time in laparoscopic adrenalectomy
Dependent variable: operative time (min). R2 = 0.31.
BMI, body mass index.
*Significant (p-value ˂ 0.05).

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Discussion

Overall, the findings demonstrate that surgical outcomes in LA improved over the 10-year period, particularly with shorter operative times, fewer intraoperative complications, and reduced hospital stays. Other parameters such as post-operative complications and readmissions remained relatively unchanged. These improvements likely reflect cumulative advancements in surgical techniques, perioperative care, and growing surgeon experience.
This study presents an evaluation of one surgeon’s 10-year experience with LA and illustrates how increasing surgical expertise, both time-based and case volume-based, enables the safe expansion of case complexity, including the resection of larger tumors. As the surgeon’s familiarity with adrenal pathology and laparoscopic approaches increased, more challenging cases were undertaken with maintained or improved safety and outcomes.
LA has been widely recognized as the standard treatment for adrenal lesions and demonstrates remarkable advantages over traditional open adrenalectomy. LA has numerous benefits, including reduced surgical trauma, lower perioperative morbidity and mortality rates, decreased blood loss, lower complication rates, reduced post-operative pain, shorter hospital stays, and improved cosmetic outcomes. These findings are consistent with the existing body of literature and further solidify the position of LA as the preferred approach for adrenal surgery (7, 8).
The most common preoperative presentation was asymptomatic incidentalomas, accounting for 50% of the cases, followed by abdominal pain (45%). The results of this study have considerable implications for patient care, emphasizing the value of chance findings during standard tests or imaging evaluations.
There is controversy regarding the appropriate size threshold for benign lesions that can be removed using laparoscopy. While some surgeons believe that only tumors smaller than 6 cm in diameter should be removed, others have reported successfully removing tumors as large as 15 cm in diameter (9, 10). In our study, the largest tumor removed laparoscopically measured 12 cm, highlighting that tumor size alone may not be an absolute contraindication in experienced hands. Although incomplete resection or tumor seeding can result in recurrent or persistent disease, meticulous surgical techniques can mitigate this complication (11).
The conversion rate to open surgery was 2%, which is lower than the reported range of 2.8–13% in the existing literature (12, 13). The average operating time for unilateral procedures was 55 min, which was less than the previously reported 145 min (7, 14).
A comparison between the preoperative biochemical and radiological diagnoses of adrenal tumors and the post-operative histopathological diagnoses revealed notable findings. Preoperatively, non-secreting adenomas were diagnosed in 36% of all cases, followed by pheochromocytoma in 33%. Post-operatively, non-secreting adenomas remained prevalent at 36%, whereas the prevalence of pheochromocytoma decreased to 31%. However, cortisol-secreting adenomas were identified post-operatively in only 8% of cases, whereas 12 cases of Cushing’s syndrome were diagnosed preoperatively. Additionally, new post-operative diagnoses emerged, including adrenocortical carcinomas (4%) and hemangiomas (3%). While aldosterone-secreting adenomas (6%) and adrenal cysts (6%) remained unchanged, these findings underscore the variability between preoperative and post-operative diagnoses, emphasizing the importance of histopathological examination in confirming adrenal tumor types, with implications for treatment planning. This is in accordance with other studies showing discrepancies between radiologic and final pathologic diagnosis (15).
To assess how surgical experience influenced outcomes, the study period was divided into two 5-year intervals. This allowed comparisons between the early and more experienced phases of the learning curve. The second group showed a significant reduction in operative time, intraoperative complications, and length of hospital stay, suggesting improved efficiency and safety with time. However, the findings of this study indicated that post-operative complications and readmission rates remained relatively constant between the two groups. These results highlight the significance of continuous evaluation and improvement in surgical procedures to enhance outcomes in patients with LA. A study by Miron et al. also demonstrated this difference (16), comparing the learning curve in laparoscopic transperitoneal adrenalectomy between the early and late experiences of a single team (6).
This series reported a mortality rate of 0%, which is similar to that of other centers that reported a range of 0–0.8%, highlighting the overall safety of LA (17).
The primary limitations of this study stem from its retrospective, observational design and the fact that all procedures were conducted by a single surgeon and team. Additionally, a considerable number of patients were lost to follow-up, leading to a smaller sample size. Therefore, the results of this study cannot be generalized to other populations. Furthermore, due to the lack of prospective control or randomization, definitive conclusions regarding causation or setting new upper tumor size thresholds cannot be made.

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Conclusion

LA, when performed by an experienced surgical team, remains a safe and effective approach for managing adrenal tumors, including selected larger lesions. While our findings support the growing body of evidence that larger tumors can be safely approached laparoscopically, the retrospective nature of the study limits the ability to define a definitive upper size threshold. These results underscore the importance of increasing surgical expertise and institutional experience in expanding the indications for LA. Prospective, multicenter studies are needed to validate these findings and to explore the role of tumor size more definitively. Comparative analyses of different approaches, such as transperitoneal, retroperitoneal, and robotic techniques, may also help refine best practices for adrenal surgery.

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Acknowledgments
I would like to thank the medical staff at the Baghdad Teaching Hospital, particularly the anesthesiology and surgical teams for their hard work and dedication, delivering patient care and maintaining the health of the community.

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Data availability
The dataset used in the current study is available on request from Muayad Abass Fadhel (E-mail: moayad.a@comed.uobaghdad.edu.iq).

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Ethical approval
This study conformed to the guidelines of the Declaration of Helsinki and received ethical approval from the Baghdad Teaching Hospital affiliated with the College of Medicine at the University of Baghdad (Approval Number: 45).

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