Utility of Retroperitoneal Laparoscopic Surgery for Retroperitoneal Tumors

Abstract

Introduction:

Retroperitoneal laparoscopic surgery for benign retroperitoneal tumors is often challenging because of variations in the tumor location and size. In this study, we present a retroperitoneal laparoscopic resection technique used at our institution to treat benign retroperitoneal tumors.

Materials and Methods:

This retrospective case series included nine consecutive patients who underwent retroperitoneal laparoscopic tumor resection between 2011 and 2023. We analyzed patients’ clinical characteristics and perioperative outcomes.

Results:

There were four women and five men with a median age of 44 (range, 15−70) years and a median body mass index of 22.0 (range, 17.8–29.2) kg/m². Among the nine tumors resected, 7 were located in the right suprahilar region, 1 in the left suprahilar region, and 1 in the left infrahilar region. The median maximal tumor diameter was 3.0 cm (range, 1.8−12). The median operative time and estimated blood loss were 144 minutes (range, 76−358) and 7 mL (range, 1−479), respectively. No major perioperative complications (Clavien–Dindo grade ≥3) or conversion to open surgery were recorded. Pathological examination confirmed negative surgical margins in all cases.

Conclusions:

Retroperitoneal laparoscopic resection was found to be a feasible and safe approach for treating benign retroperitoneal tumors.

INTRODUCTION

Retroperitoneal tumors, both benign and malignant, originate from the retroperitoneal tissue or embryonic remnants of the urogenital ridge.^1,2 Benign retroperitoneal tumors are rare and usually detected incidentally; they are commonly asymptomatic until they grow large enough to cause compressive symptoms due to pressure on adjacent structures, nerves, or organs.³ Considering the characteristics of benign tumors, minimally invasive R0 surgical resection (microscopically complete resection) is necessary and important.⁴

Recent studies have demonstrated the utility of laparoscopic resection as the standard minimally invasive treatment for benign retroperitoneal tumors.^4,5 However, most studies have focused on the transperitoneal approach, while studies using the retroperitoneal approach are scarce.^3,6 Although the retroperitoneal approach has the disadvantage of fewer anatomical landmarks and a smaller working space, it has several advantages, including less interference with the abdominal viscera and a more direct route to the tumor compared with the transperitoneal approach.⁷

In this study, we present the surgical technique and operative outcomes of the retroperitoneal laparoscopic approach used at our institution for the treatment of benign retroperitoneal tumors.

MATERIALS AND METHODS

Patients

This retrospective case series included nine consecutive patients who underwent retroperitoneal laparoscopic resection of retroperitoneal tumors at our hospital between 2011 and 2023. All patients underwent preoperative abdominal computed tomography or magnetic resonance imaging and endocrinological examinations, and all tumors were diagnosed as nonfunctional benign tumors. We usually performed contrast-enhanced computed tomography. However, when we could not use the contrast agent, we performed nonenhanced magnetic resonance imaging.

Surgical Technique

The preoperative images were used to identify the tumor size and localization and analyze its relationship with surrounding structures (Figures 1A, 1B, and 1C). After general anesthesia was introduced, patients were placed in the lateral decubitus position. A skin incision of approximately 2 cm was made below the tip of the eleventh rib to insert the laparoscope port (Figure 2). Sharp and blunt dissection was performed until the retroperitoneal space was reached. The retroperitoneal space was expanded using a PDB kidney-shaped balloon (Medtronic Japan, Tokyo, Japan) inserted through the initial skin incision. To prevent peritoneal rupture, the PDB balloon was dilated until the large balloon wrinkle was stretched (Figure 3A). Next, a 12-mm blunt port trocar for the 30-degree laparoscope was inserted and carbon dioxide was instilled, with the pressure maintained at 10 mmHg. One 12-mm and one 5-mm trocars were placed ventrally and dorsally, respectively, to the blunt trocar for the camera port (Figure 2). If necessary for retracting the kidney or inferior vena cava (IVC), an additional 5-mm trocar was placed at the tail side of the ventral port (Figure 2). The lateroconal fascia was dissected longitudinally and as much as necessary of the retroperitoneal fat was removed (Figure 3B). The retroperitoneal space was expanded until the psoas or quadratus lumborum muscles were exposed. Tumors were usually identified near the IVC, abdominal aorta, or kidney vessels (Figures 3C and 3D). Following dissection of the surrounding tissues, including vessels or branches, they were sealed and cut using a vessel sealing device. To avoid injuring the IVC, lumbar, or renal veins, surgical manipulation in adjacent tissues was performed very carefully using an assistant retractor or by changing the angle of the 30-degree laparoscope (Figures 3E and 3F). The tumor was ultimately isolated and removed using a laparoscopic specimen retrieval bag. Draining tubes were not placed in any of the cases.

Figure 1.

Abdominal computed tomography findings in case 4. (A) Axial image showing a right-sided retroperitoneal tumor (white arrow). (B) Coronal image showing a right-sided retroperitoneal tumor (white arrow) adjacent to the renal artery (white triangle). (C) Sagittal image showing a right-sided retroperitoneal tumor (white arrow) adjacent to the inferior vena cava (white triangle).

Figure 2.

Schema of trocar placement. The figure shows the placement of the 12-mm camera port (black circle), 12-mm robotic port (white circle), 5-mm port (black triangle), and 5-mm assistant port (white triangle).

Figure 3.

Intraoperative findings in case 4. (A) The retroperitoneal space was dilated using a PDB balloon. (B) The lateroconal fascia was dissected longitudinally. (C) The tumor (white triangles) was located adjacent to the right RA. (D) The tumor (white triangles) was dissected from the RA and IVC. (E) Detachment of the tumor (white triangles) from the IVC was assisted using an assistant retractor. (F) Angle change of the 30-degree laparoscope. IVC, inferior vena cava; RA, renal artery.

RESULTS

Patient Characteristics

Patient characteristics are shown in Table 1. There were four women and five men with a median age of 44 (range, 15−70) years and a median body mass index of 22.01 (range, 17.76–29.17) kg/m². The tumors were located in the right suprahilar (n = 7), left suprahilar (n = 1), or left infrahilar (n = 1) regions (Figure 4). The median tumor diameter was 3.0 (range, 1.8−12) cm. No conversion to open surgery, blood transfusion, or major perioperative complications (Clavien–Dindo grade ≥3) were recorded.

Table 1.

Patient Characteristics

Patient No.	Sex	Age (years)	BMI (kg/m2)	Tumor Location	Tumor Size (cm)
1	Male	70	28.0	Left suprahilar	2.2
2	Female	37	22.0	Right suprahilar	1.8
3	Female	74	21.3	Right suprahilar	4.8
4	Male	67	29.2	Right suprahilar	12
5	Male	50	26.2	Right suprahilar	3
6	Male	27	21.9	Left infrahilar	2
7	Female	44	20.0	Right suprahilar	3
8	Female	38	17.8	Right suprahilar	2
9	Male	15	27.1	Right suprahilar	9

Abbreviation: BMI, body mass index.

Figure 4.

Schema of the tumor location in our population.

Perioperative Outcomes

Perioperative outcomes are presented in Table 2. The median operative time and estimated blood loss (including saline solution for washing) were 144 (range, 76−358) min and 7 (range, 1−479) mL. The median postoperative hospital length of stay was 5 (range, 3−9) days. Pathological examination confirmed negative surgical margins in all cases, and no recurrence was observed in any of the patients at a median follow-up of 35 (range, 1–107) months.

Table 2.

Perioperative Data

Patient No.	Operative Time (min)	Blood Loss (mL)	Length of Stay	Pathology
1	351	181	9	Paraganglioma
2	87	9	5	Schwannoma
3	147	7	8	Schwannoma
4	358	479	6	Schwannoma
5	131	7	5	Schwannoma
6	144	7	5	Schwannoma
7	93	3	3	Schwannoma
8	76	0	5	Schwannoma
9	189	11	4	Ganglioneuroma

DISCUSSION

The standard treatment for benign retroperitoneal tumors is surgical R0 resection.⁸ Recent advancements in laparoscopic instruments, energy devices, imaging technology, and anatomical knowledge under laparoscopic surgery have made minimally invasive treatment for benign retroperitoneal tumors feasible and safe.^3,4,6,9,10 Retroperitoneal tumors frequently occur adjacent to major vessels, including the IVC, abdominal aorta, and renal arteries or veins. In such cases, the magnified visual field and fine dissection under laparoscopy contribute to avoiding major bleeding. Compared with open surgery, laparoscopic surgery for benign retroperitoneal tumors has been shown to have similar perioperative outcomes, including operative time, blood loss, and complications.^11–13 Although the robotic surgery with advantage including three-dimensional high-resolution vision and multidimensional robotic arms, can facilitate minimally invasive surgery for retroperitoneal tumors, it has the disadvantage with higher cost.¹⁴ The present study reiterated the superiority of laparoscopic surgery.

Laparoscopic access routes for benign retroperitoneal tumors include the transperitoneal and retroperitoneal approaches, both of which have certain advantages. While the transperitoneal approach provides good orientation and wider working space, the retroperitoneal approach enables direct access to the tumor and is associated with a smaller risk of abdominal organ injury.^4,7 However, retroperitoneal tumors located on the right side are often adjacent to the dorsal aspect of the IVC. Thus, such tumors are difficult to visualize fully using the transperitoneal approach, and there is the risk of small vessel injury around the IVC during traction. Although it provides a smaller working space than the transperitoneal approach, the retroperitoneal approach offers direct access to such tumors as well as a good orientation regarding the relationship between the tumor and IVC. It is because of this advantage that we opted for the retroperitoneal approach for benign retroperitoneal tumors, particularly those located on the right side. Furthermore, our case series demonstrated that an angle change of the 30-degree laparoscope enables a good view of the relationship between the tumor and IVC.

Retroperitoneal tumors vary in size; however, the maximal diameter of benign tumors is usually less than 10 cm, whereas larger tumors are rarely diagnosed. Previous studies have reported that tumors eligible for safe laparoscopic resection are those less than 10 cm in size.^3,4,6,7 Although retroperitoneal tumors with a maximal diameter of more than 10 cm are generally treated by open surgery, several studies have demonstrated the utility of laparoscopic or robotic resection for these tumors.^14–16 In these cases, the transperitoneal approach was adopted due to the wider working space.^14,15 In our study, we performed retroperitoneoscopic resection of a tumor with a maximal diameter of 12 cm. In this case, the operative time was longer and the blood loss was greater than in cases with tumors less than 10 cm in size. However, the postoperative course was uneventful with no perioperative complications or requirement for blood transfusion. The postoperative hospital stay was longer in our cases than in the previous report.⁴ Because universal health coverage in our country requires patients, except for older adults and children, to pay only 30% of the total hospital charge, patients usually prefer delayed discharge.⁹ Nonetheless, we consider that the transperitoneal approach is a better option for tumors located between the IVC and aorta.¹⁷ Thus, we consider that both the tumor size and location are important for selecting the surgical approach.

This study had some limitations. In addition to the inherent limitations of the retrospective design, our sample size was small, limiting the generalizability of the findings. However, this was due to the rarity of the disease. Despite these limitations, this study corroborated the feasibility and safety of the retroperitoneal approach for the surgical treatment of benign retroperitoneal tumors.

CONCLUSIONS

We successfully performed retroperitoneoscopic resection of benign retroperitoneal tumors, with no cases of conversion to open surgery, blood transfusion, or complications. The retroperitoneal approach should be considered as an option for minimally invasive surgery for benign retroperitoneal tumors.