Impact of Previous Infection on Perioperative Outcomes of Thoracoscopic Lobectomy for Congenital Lung Malformation

Introduction

In patients with congenital lung disease (CLD), surgical resection is generally performed to prevent recurrent respiratory infection and malignant transformation ¹ ; however, there is no consensus regarding the indication and timing of the procedure, especially in asymptomatic patients. Surgical intervention during the infantile period is recommended because most of the patients develop symptoms by the age of 3 years, which could make the surgery technically more difficult.^1–3

The thoracoscopic approach has gained popularity due to its safety and feasibility, and 61% of lung resections in the Japanese pediatric population are performed thoracoscopically, according to the annual report of the national clinical database published in 2019 (in Japanese). ⁴ However, little is known about the effects of preceding infection on intra- and postoperative results.

This study aimed to evaluate the impact of prior infections on perioperative outcomes of patients who underwent thoracoscopic lobectomy for congenital lung anomalies.

Materials and Methods

This retrospective observational study was conducted at a single institution. Patients who underwent thoracoscopic resection for CLDs between January 2009 (after the procedure was adopted in our department) and October 2021 were enrolled in the study. Patients with extralobar sequestration and those who underwent segmentectomy or wedge resection were excluded. Patient data, including sex, histological, and prenatal diagnoses, detailed information about episodes of respiratory infection before surgery, age and weight at the time of the procedure, duration of the procedure, amount of intraoperative blood loss, conversion to open procedure, reoperation, and length of hospital stay, were retrieved from the medical records and compared between the patients with infection (Group 1) and those without infection (Group 2).

Our treatment strategy for congenital lung malformations is as follows: For cases with an antenatal diagnosis, urgent thoracoscopic resection is planned even during the neonatal period, if respiratory distress is observed. However, if the affected neonate is asymptomatic, elective surgery is performed between 6 and 12 months of age. For patients with previous respiratory infections, definitive surgery is scheduled at least 3 months after its resolution (an interval of 6 months between the resolution of the infection and surgery seems ideal, and the surgery is scheduled >6 months postinfection, if possible).

Statistical analysis was performed using the Steel–Dwass method for multiple nonparametric comparisons and Fisher's exact test for contingency tables using commercially available software (JMP Pro 11.0.0; SAS Institute Japan Ltd., Tokyo, Japan). Statistical significance was set at P < .05. All data are shown as median (range).

This study was approved by the research ethics committee of Saitama Children's Medical Center, and the requirement for written informed consent was waived because of the retrospective nature of this study.

Results

Table 1 shows patient characteristics and perioperative outcomes. We enrolled 34 patients: 13 in Group 1 and 21 in Group 2. Patient data, including sex-based distribution and pathological diagnosis, were similar between the two groups. Overall, 1 patient in Group 1 (7.7%) and 18 patients in Group 2 (86%) had been prenatally diagnosed with malformations (P < .001).

In Group 1, the age at initial infection was 42 (0–105) months, and the number of episodes of infection was 1 (1–4). As described before, our strategy to treat patients in Group 1 was to have a predefined interval between the resolution of infection and the procedure. However, due to refractory infection, 2 patients underwent surgical intervention 7 and 21 days after the resolution of infection, respectively. The other patients completed the desired interval between the resolution of the infection and surgery without recurrence of infection, and the median (range) interval was 157 (7–323) days.

The median (range) age and weight at the time of the procedure in Groups 1 and 2 were 70 (3–130) months versus 9 (4–163) months and 17.4 (6.3–34.4) kg versus 8.7 (6.5–59.4) kg, respectively, and both showed significant differences between the two groups (P = .0023 and .0010, respectively). The procedure duration was comparable (310 [228–681] minutes in Group 1 and 285 [189–419] minutes in Group 2; P = .23). The amount of blood loss was significantly higher in Group 1 (60 mL [0–350 mL]) than in Group 2 (20 mL [0–85 mL]) (P = .0042).

Four patients in Group 2 required reoperation due to air leakage from the bronchial stump (N = 2), pyothorax that required drainage tube insertion, and cardiac tamponade that was likely to be caused by the end of the monofilament suture ligating the pulmonary vein and resolved by pericardial drainage; however, none of the Group 1 patients required reoperation (P = .12). No conversion to thoracotomy was required in either group. There was no significant difference in the duration of postoperative admission between the two groups (Group 1: 6 [3–10] days versus Group 2: 6 [4–14] days; P = .14).

Discussion

This retrospective observational study showed that preceding infection increased the volume of blood loss during thoracoscopic lobectomy but had little effect on the duration of the procedure, rate of conversion to open surgery, incidence of complications, and duration of admission. We believe that our findings justify the early resection of CLD because thoracoscopic lobectomy after respiratory infections can increase the amount of intraoperative bleeding and the possibility of requiring blood transfusion.

The benefit of surgical resection of CLD in asymptomatic cases is debatable; however, surgery is recommended in the first year of life because majority of the patients manifest symptoms by the age of 3 years. ¹ An expert insists that manipulations are technically easy to perform in infants weighing ∼5 kg, although the working space is smaller than that in older infants in whom inflammation makes it difficult to identify and dissect the vessels. ² Elhattab et al reviewed patients who underwent thoracoscopic lobectomy and segmentectomy for CLD and showed that previous pulmonary infections increased the duration of the procedure, caused postoperative fever, and increased the need for antibiotics.

Although there were no significant differences in the incidence of postoperative complications between patients who had infections and those who did not, they advocated that surgery should be completed by the age of 1 year to prevent infection before the procedure. ³ Clark et al compared perioperative outcomes of patients who underwent resection of congenital lung lesions by thoracoscopy with those of patients who underwent thoracotomy. Age <1 year, absence of episodes of previous respiratory infection and resolution before surgery, and less blood loss were identified as predictive factors for successful thoracoscopic procedures. ⁵

Our findings also support early surgical intervention before the onset of symptoms for CLD. Although not statistically significant, the incidence of reoperation was higher in Group 2 than in Group 1. Subgroup analysis of Group 1 to evaluate the difference between those who underwent reoperation and those who did not showed no significant differences in age and weight at the time of surgery, and the amount of bleeding (data not shown). However, the procedure time was significantly longer in cases with reoperation (335 [322–350] minutes) than those without (279 [189–418] minutes; P = .0122). The cases that required reoperation might be more technically challenging as well.

This study has some limitations. The number of included patients was small, and data were collected retrospectively from a single institution. Moreover, all surgeries were not performed by a single surgeon, although attending surgeons qualified by the endoscopic surgical skill qualification system ⁶ supervised all procedures. These issues might have introduced bias into the data and findings.

Despite these limitations, this study showed that respiratory infections before thoracoscopic lung lobectomy increased the amount of blood loss. We insist that surgical intervention for CLDs should be performed before the age of 1 year to avoid unnecessary intraoperative bleeding and blood transfusions.