Right middle lobe torsion after right upper lobectomy despite pneumopexy in an adult: a case report and review of the literature

Abstract

Background

Right middle lobe (RML) torsion is the most common form of lobar torsion. It usually happens after right upper lobe (RUL) lobectomy, especially when pneumopexy is not performed. Although various surgical techniques have been introduced to prevent RML torsion, the efficacy of these techniques is not yet fully understood. We herein report a case of RML torsion that happened after RUL lobectomy despite pneumopexy together with a literature review.

Case presentation

A 62-year-old female patient underwent RUL lobectomy due to adenocarcinoma of the lung. Prophylactic pneumopexy with a single stitch was performed to fix RML to the right lower lobe. RML was well inflated and did not rotate before wound closure was performed. However, the patient complained of foreign body sensation inside her chest on postoperative day 5, and a chest X-ray revealed atelectasis of RML. Bronchoscopy showed a collapsed middle lobe bronchus. Exploratory thoracotomy showed congested RML with a twisting bronchovascular pedicle, and therefore, RML lobectomy was performed.

Conclusions

RML torsion is a rare but potentially fatal condition requiring high clinical alertness. Through our literature review and the presented case, we demonstrate that RML torsion may occur despite pneumopexy. A combination of surgical methods, such as the use of continuous sutures or fibrin glue, may be more effective in preventing torsion.

Background

Lobar torsion is defined as convolution of the bronchovascular pedicle contributing to ischemia or infarction of the pulmonary lobe [1]. It is a rare and almost always fatal condition, which usually requires emergent surgery [2]. Among all of the lung lobes, right middle lobe (RML) torsion is the most prevalent and accounts for 70% of lobar torsion and 5% of unplanned reoperation after surgical intervention for lung cancer [3, 4]. Lobectomy of the right upper lobe (RUL) is the most common etiology of RML torsion, especially when pneumopexy is not performed to anchor RML to the right lower lobe (RLL) [5, 6]. Despite the known association between RUL lobectomy and RML torsion, the effectiveness and technique of pneumopexy in preventing this complication remains inadequately understood due to the rarity of the condition [6]. Herein, we present a case with RML torsion after right upper lobectomy despite pneumopexy. Our objective is to elucidate the limitations of pneumopexy utilizing single stitches by examining this case study. Additionally, we aim to enhance the understanding of preventive strategies for RML torsion through a comprehensive literature review. (Fig. 1).

Fig. 1

A Chest X-ray revealed patchy opacification mimicking Golden S-sign and diaphragmatic tenting over right lung, suggesting consolidation of right middle lobe (RML) B Bronchoscopy showing compromised right middle bronchus (RMB) with hyperemic mucosa and intact right lower bronchus (RLB) C Contrast-enhanced chest computed tomography showing collapsed RML bronchus (arrow) and consolidation of RML D Exploratory thoracotomy revealed hemorrhagic infarction of RML, and the staple line of minor fissure turned toward right lower lobe. The stitch (triangle) for pneumopexy were still in place, tethering RML to RLL

Methods

The electronic medical records for this case were retrospectively collected from the database of Taichung Veterans General Hospital (TCVGH) in October, 2023. Informed consent was not obtained from the patient since the waiver or alteration would not adversely affect the welfare of the subjects. This study was approved by the Joint Institutional Review Board of TCVGH (approval number: CE24276B).

For the literature review, we searched articles from PubMed, MEDLINE, Embase, and Web of Science up to October 2023. To exclude spontaneous torsion, we used the term “right middle lobe torsion”, NOT “spontaneous torsion” in combination in our search of the databases. No other restrictions were applied. We manually excluded articles without full-text in English. To focus on adult cases, pediatric cases were excluded as well. After removing duplicate articles and applying exclusion criteria, 29 studies with 32 cases of postoperative RML torsion, in addition to the present case, were obtained (Fig. 2). With respect to the screening of papers in the literature, one reviewer (C.H. Hsiao) screened all of the studies and if there was any uncertainty about whether to include an article, discussions were held with another reviewer (M.J. Lee).

Fig. 2

Flow diagram of study selection for systematic review RUL, right upper lobe; LUL, left upper lobe

Case presentation

A 62-year-old female was admitted to our hospital for surgical intervention for lung adenocarcinoma. She underwent video-assisted thoracoscopic (VATS) RUL lobectomy, S6 segmentectomy, and mediastinal lymph node dissection. Based on preoperative computed tomography (CT), the length of the right middle bronchus was 21 mm. Intraoperative anatomic evaluation revealed an incomplete minor fissure and a complete major fissure. The right middle bronchus was relatively long. Inferior pulmonary ligament was not dissected. During lung expansion, RML moved cephalically but did not rotate at the pedicle. Since the RML was highly movable after RUL lobectomy, pneumopexy with a single stitch was performed to attach the RML to the RLL after lung expansion. The patient was under stable condition after the procedure.

However, on postoperative day (POD) 5, the patient reported a sensation of a foreign body inside her chest, particularly during inspiration. Despite this symptom, she did not exhibit respiratory distress and maintained a saturation of 99% on room air. Laboratory blood tests were within normal limits. Chest X-ray (CXR) revealed patchy opacification over the right upper lung field (Fig. 1A). Given the absence of infection signs and lack of productive cough, atelectasis caused by postoperative sputum obstruction was unlikely. Under the suspicion of RML torsion, bronchoscopy was arranged, which showed compromised right middle bronchus (Fig. 1B). To exclude the possibility of external compression, an urgent contrast-enhanced chest CT was performed, which revealed partially collapsed and consolidated RML and intact RLL (Fig. 1C). Based on the aforementioned findings, RML torsion was suspected.

The patient subsequently underwent VATS exploratory thoracotomy later on the same day, which revealed necrotic RML with hemorrhagic congestion. The pedicle of the RML was rotated 180° clockwise. The previous stitch of the pneumopexy was still well in place (Fig. 1D). The RML was considered nonviable, and hence RML lobectomy was performed. Follow-up chest radiograph on POD 3 showed sufficient expansion of remnant RLL. Her foreign body sensation also subsided after the surgery. Under stable condition, the patient was discharged on POD 6 following the second operation.

Discussion and conclusions

The incidence of postoperative lobar torsion is 0.09% to 0.4% [7]. Although it is rare, the overall mortality of lobar torsion can reach up to 8.3%, requiring high vigilance [8, 9]. Various fixation methods have been introduced to prevent twisting of the RML pedicle after RUL lobectomy, including suturing, absorptive anti-adhesive sheet, fibrinogen/thrombin-based collagen fleece, and fibrin glue [6]. However, due to the rarity of RML torsion, it is difficult to initiate a prospective study to validate the effectiveness of prophylactic pneumopexy. In the present case, RML torsion occurred after RUL lobectomy in spite of prophylactic pneumopexy. This spurred our curiosity to determine whether pneumopexy with a single stitch is sufficient to prevent lobar torsion.

Of the 33 cases, 17 (51.5%) were male and 16 (48.5%) were female. The median age was 61 (range: 26 to 82) years old (Table S1) [2, 5, 10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. Twenty-six (79%) cases were initially diagnosed as lung cancer, 3 (9%) were end-stage pulmonary disease, 2 (6%) were esophageal cancer, 1 (3%) was infectious cavitary lesion, and 1 (3%) was bronchiectasis. Their initial operation was RUL lobectomy in 28 (85%) cases, lung transplant in 3 (9%) cases, and esophagectomy in 2 (6%) cases. The median time to diagnosis of RML torsion was 2.5 (range: 0 to 14) days following the initial operation. The most common initial sign of RML torsion was fever (33%), and 9 (27%) cases had unstable conditions, including unstable hemodynamics, desaturation, and inability to wean off endotracheal tube or vasopressors (Fig. 3). Of note, 8 (24%) cases were asymptomatic and torsion was diagnosed when atelectasis was incidentally found on postoperative chest X-ray. Among the 33 cases, 23 (70%) patients showed unviable RML and required RML lobectomy, and detorsion of RML was only performed in 9 reported cases (Table S2).

Fig. 3

The first symptom and sign reported in cases of RML torsion

In our review of the literature, only 3 cases received pneumopexy at the initial operation, and all of them involved fixation of RML to RLL (Table 1). The day of torsion diagnosis varied from POD 1 to 9. Some predisposing factors increased the risk of torsion in these cases. First, the pulmonary ligament was dissected in case 1 and case 25, and major fissures were complete in all three cases [17, 29, 32]. Both dissection of pulmonary ligament and anatomically complete fissure resulted in high mobilization of the residual middle lobe, which increased the risk of torsion [35]. Moreover, S6 segmentectomy in cases 2 and 3 led to a larger intrathoracic free space, allowing the residual lung to twist or displace.

Table 1 Cases of RML torsion despite pneumopexy performed at initial operation

In the present case, a complete major fissure increased the risk of RML torsion [36]. Also, Hasegawa et al. reported that the right middle bronchus was longer in patients with RML syndrome compared to the control group (22.4 ± 3.5 vs. 14.6 ± 3.2 mm, P < 0.01) [37]. A relatively long right middle bronchus (21 mm) in our case may have accordingly facilitated twisting of the RML. However, we did not mobilize the pulmonary ligament. Also, the bronchovascular pedicle did not twist upon reinflation of the lung. We performed pneumopexy after lung expansion to avoid uncertainty about the possibility of RML displacement during reinflation. However, RML torsion still occurred after RUL lobectomy. We speculate that a single stitch may not be enough to stabilize RML. With only a single stitch, there is only one fixation point for RML, allowing greater rotational freedom and remaining possibility of torsion. To better stabilize RML in three-dimensional space, we suggest that linear fixation methods, such as continuous sutures, or planar attachment techniques, such as fibrin glue, may offer more effective stabilization. Sakai et al. performed an over-and-over continuous suture to prevent recurrence after detorsion of RML [7]. Pulle et al. performed pneumopexy with multiple interrupted sutures [24]. Yanagihara et al. used anchoring stitches together with fibrin glue in one case after RML detorsion [22]. In the aforementioned studies, all cases were reported to have an uneventful outcome during follow-up. However, the application of absorptive sheet and fibrin glue alone may not be strong enough to anchor RML [29]. Even though Venuta et al. reported that fibrin glue itself may be sufficient to prevent lobar torsion with a very low complication rate, this technique was performed in only 9 cases and the external validity remains uncertain [38]. Higashiyama et al. therefore claimed that a combination of fixation techniques should be applied to prevent RML torsion [6]. However, there is still no consensus on the indication for pneumopexy or the optimal surgical technique [6, 39].

In our opinion, a minimum of either multiple stitches or continuous suture should be performed to ensure effective prevention, based on previous studies [7, 22]. The application of multiple or single pneumopexy technique should depend on careful intraoperative risk assessment, including length of middle lobe bronchus, mobilization of pulmonary ligament, presence of complete major fissure, concurrent sublobar resection, and displacement of RML during lung reinflation [29, 36]. A single technique may not be sufficient to prevent torsion in some cases [17]. Moreover, the development of unwanted adhesion caused by multiple pneumopexy technique could become a concern if re-thoracotomy is required for second primary lung cancer [6]. In clinical settings, the financial burden imposed by the use of fibrin sealant and the high number needed to treat should be taken into consideration. Finally, in a case report of RML preservation after right upper and lower bilobectomy, stitches were employed for fixation of RML to the chest wall and pericardial fat. The postoperative follow-up revealed absence of torsion [40]. Although it was only an experience from a single case, fixation of RML to the chest wall can be taken into consideration in patients at high risk of torsion.

In summary, the clinical course of RML torsion may be insidious and asymptomatic, requiring high vigilance. The diagnosis of RML torsion may rely on routine follow-up of CXR during the first two weeks after the operation [13]. It is possible to preserve RML by simply allowing detorsion after unwinding the pedicle, which would result in immediate restoration of perfusion [28, 31]. However, RML lobectomy should be promptly conducted if the lobe is congestive and necrotic [13]. Pneumopexy was advised in cases undergoing RUL lobectomy to prevent torsion, but the fixation technique should be optimized with a careful intraoperative risk assessment [17, 35].

To the best of our knowledge, we are the first to conduct a literature review focusing on postoperative RML torsion, which is the most common lobar torsion. We are also one of the few case reports of postoperative RML torsion despite pneumopexy. It is important to make a comprehensive risk evaluation for RML torsion intraoperatively. A combination of surgical fixation techniques should be applied for high-risk patients. Given the rarity and potentially fatal consequences of RML torsion, future research to deepen our understanding of effective prevention methods would be valuable. This could include prospective case–control studies evaluating pneumopexy techniques, as well as biomechanical studies exploring the physical mechanisms that contribute to torsion.