Laparoscopic Adrenalectomy in Children: A Multicenter Experience

Introduction

Laparoscopic adrenalectomy is now being recognized as the standard approach for adrenalectomy for benign lesions in adults. The published experience in children and adolescents has been limited to sporadic small case series. Therefore, we conducted a large multicenter review of children who have undergone laparoscopic adrenalectomy.

Methods

After obtaining institutional review board approval, a retrospective review was conducted on all patients who have undergone laparoscopic adrenalectomy at 12 institutions over the past 10 years.

Demographic patient data, operative data, lesion size, lesion pathology, and outcomes were recorded. Pre- and postoperative treatment plans were recorded. Operative times included unilateral adrenalectomy without concomitant procedures.

Data are expressed as mean±standard deviation. Continuous variables were compared using an independent-sample two-tailed Student's t-test. Discrete variables were analyzed with chi-square test. Significance was defined as P value <of .05.

Results

About 140 patients were identified of which 70 were males (50%). Laterality included 76 (54.3%) left-sided lesions, 59 (42.1%) right, and 5 (3.6%) bilateral. Age, weight, lesion size, and operative time are listed in Table 1. The mean operative time for all cases including combination procedures and bilateral adrenalectomy was 140.7±70 minutes (range 43–406 minutes). The mean number of ports used was 4.0 (range 3–6), including an average of 3.8 for left-sided lesions, 4.1 for right-sided lesions, and 5.4 for bilateral.

Most common pathology was neuroblastoma in 39 cases (27.9%), of which 23 (59.0%) had undergone preoperative chemotherapy. Display of pathology with mean lesion size and conversion rates are listed in Table 2.

There were 13 conversions to an open operation (9.9%). Most conversions were because of tumor adherence to surrounding organs. There were no differences in patient or tumor characteristics between the cases converted to open and those completed laparoscopically (Table 3).

A blood transfusion was utilized in 4 cases, of which 2 were due to operative losses (1.4%) and the others appear have been given empirically where 50 cc was given in 2 separate cases with documented losses of 25 and 5 mL. In the 2 cases where transfusion was required, the estimated losses were 125 and 900 mL prompting 300 and 600 cc transfusion in those cases. The single case with large loss was because of left adrenal vein hemorrhage requiring conversion.

The only postoperative complication was renal infarction after resection of a large neuroblastoma in an infant that required skeletonization of the renal vessels. At a median follow-up of 18 months, there was only one local recurrence, which was in a patient with a pheochromocytoma.

Based on size, there were 23 lesions >6 cm. The mean operative time was 172 minutes for the large lesions compared with 123 minutes for those <6 cm (P=.003). The conversion rate was 17.4% for the larger lesion compared with 7.7% for the smaller lesions (P=.23).

Discussion

There have been multiple small case series of laparoscopic adrenalectomy published in the pediatric literature, including 20 of the patients herein who were previously described in single center series.^1–4 As is often the concern with advanced techniques, a publication bias develops with a few surgeons publishing results that may not translate to the practicing community. This large multicenter series represents the experience approximately 50 surgeons to provide a generalizable view of the contemporary experience in children. The 10% conversion rate in this series establishes a benchmark for consulting families on likelihood of completing the operation laparoscopically. Also valuable for consultation and operative preparation is the confirmation of previous reports that the risk for requiring a blood transfusion is low (<2%). Additionally, this series documents the full spectrum of pathology that has been approached laparoscopically in children.

Several questions about laparoscopic adrenalectomy in children have been posed by authors over the course of the current published experience. The issues include the size limit for the patients, the size limits for the adrenal mass, and the role of laparoscopy for malignancy.

Some authors have suggested that there are no age or weight limits. ⁵ Our series confirms this suggestion as there were 7 patients under a year of age, with the smallest patient being 6 days old and 3.4 kg. In this case, a neuroblastoma tucked behind the confluence of the right renal vein and vena cava; however, there were no technical issues as the dissection proceeded without overwhelming difficulty. This suggests that it is reasonable to begin the operation laparoscopically if the surgeon is comfortable with this operation independent of patient size.

Another debate in the literature is maximum size of lesion that should be approached laparoscopically. A 6 cm limit was initially posed in the adult literature based on risk of malignancy. ⁶ This was subsequently challenged by several series documenting laparoscopic resection of adrenal masses over 6 cm when not limited by invasion.^7–13 Specifically comparing laparoscopic results with lesion over versus under 6 cm in a large adult series, operative times were comparable but the conversion rate was higher with larger lesions. We found significantly greater operative times with lesions >6 cm, and while the conversion rate was 10% higher with the larger lesions, this difference was not significant. Our series makes a strong argument for approaching larger lesion lesions laparoscopically when the lesion is otherwise circumscribed and not infiltrating surrounding structures.

As for the risk of malignancy, several of the series challenging the size limit found that despite malignant potential, there was a low rate of adrenocortical carcinoma. ⁸ When malignancy is discovered, several authors have found that the risk of local recurrence is also low.^10–13 In children, the concerns and rules for malignancy are different. As opposed to the adult population, the most common adrenal malignancy in children, neuroblastoma, is also the most common indication for adrenalectomy. Neuroblastoma biologically differs from adult lesions in its propensity to respond to chemotherapy by disappearing or differentiating such that the principles of resection do not follow standard oncologic principles. These lesions should be resected to the extent feasible without injury to surrounding organs, which makes it reasonable to approach some of these laparoscopically, knowing resection to negative margins is not necessary. A separate question for neuroblastoma is whether these can be approached laparoscopically after response to chemotherapy. The concern is that tumor is often initially infiltrating around multiple central vessels, making it unresectable, which prompts the preoperative chemotherapy. When the lesion has a dramatic response to become a single suprarenal lesion, the surgeon does not know how much of the former tumor will be scar, making it difficult to identify dissection planes. This series answers the question with an affirmative that postchemotherapy neuroblastomas can be approached laparoscopically. There were 24 such cases performed in this series with a conversion rate of 12.5%, which is comparable to the entire series, and less than the 20% conversion rate seen in the neuroblastomas approach before therapy.

The International Pediatric Endoscopic Group published guidelines for the surgical treatment of adrenal masses in children, stating that although there were no absolute contraindications, cases should be carefully selected. ¹⁴ Our data suggest that lesions without involvement of surrounding structures can be approached laparoscopically regardless of the size of the lesion, size of patient, or suspected pathology.