Rigid-Flexible Bronchoscopy With Holmium Laser Cauterization for Pine Nut Shell Removal and Balloon Dilation for Subsequent Bronchial Stenosis in a 16-Month-Old Girl

Introduction

Foreign body aspiration (FBA) is a life-threatening emergency, characterized by the lodging of food, toys, or other objects within the airway [1]. This condition results in a wide spectrum of clinical manifestations, ranging from mild coughing to complete airway obstruction, respiratory failure, and even death [2]. Hard organic foreign bodies such as nut shells pose distinct clinical challenges due to their rigid texture, deep impaction in peripheral bronchi, and high risk of airway trauma during conventional removal. Organic materials, including nuts, commonly trigger inflammatory reactions and granuloma formation, while delayed or inappropriate management often leads to post-obstructive pneumonia, atelectasis, and secondary bronchial stenosis, further increasing treatment difficulty and can require invasive interventions [3,4].

Children aged 1 to 3 years are at the highest risk of FBA owing to immature laryngeal reflexes and oral exploratory behavior [5]. Approximately 20% of cases lack a clear aspiration history, and the diagnostic value of chest radiography is limited, underscoring the importance of clinical suspicion [6]. Emergency bronchoscopy is the first-line diagnostic and therapeutic approach for suspected FBA, enabling foreign body localization and minimally invasive retrieval [7]. However, rigid or flexible bronchoscopy alone is often insufficient for deeply impacted hard foreign bodies, and post-removal bronchial stenosis remains a difficult complication to manage. This case report presents the clinical application of a combined rigid and flexible bronchoscopy technique with holmium laser fragmentation for foreign body removal, followed by sequential balloon dilation for the treatment of post-FBA bronchial stenosis in a young child.

Case Report

A 16-month-old girl presented with a 6-day history of cough and dyspnea and 5-day history of fever and hoarseness, with symptom exacerbation on the last day. After accidental pine nut ingestion on January 21, 2025, she developed paroxysmal nocturnal coughing, sputum retention, and dyspnea. Initial evaluation at an adult hospital, including chest CT and otorhinolaryngology examination, was unremarkable, with no treatment given. Subsequently, she developed 40°C fever, persistent cough, and hoarseness, and was diagnosed with pneumonia, receiving 2 days of unspecified intravenous therapy without improvement. Treatment was adjusted to amoxicillin-clavulanate (January 25 to 27), azithromycin and methylprednisolone (January 27), resolving the fever but not the cough, dyspnea, or hoarseness. On the morning of January 27, she suddenly had cyanosis, moaning, severe respiratory distress, and SpO drop to 85%, requiring emergency interventions. After transfer to a children’s hospital, chest CT suggested a bronchial foreign body (Figure 1A). Incomplete foreign body removal via flexible bronchoscopy was attempted. A follow-up CT on January 28 (Figure 1B) showed occlusion of the right lower lobe basilar segment bronchus, indicating foreign body migration. Intubated and mechanically ventilated, the child was transferred to the Pediatric Intensive Care Unit.

The patient had an unremarkable medical history and presented in good health. Vital signs included a temperature of 36.9°C, heart rate of 138 bpm, respiratory rate of 47 breaths/min, and blood pressure of 94/49 mmHg. Under sedation with endotracheal intubation and mechanical ventilation, oxygen saturation was 100%. Right lung auscultation revealed reduced breath sounds and dry rales. Cardiac examination showed a regular rhythm, strong heart sounds, and no precordial murmurs. The abdomen was soft, with no hepatosplenomegaly. Neurological examination was negative, and there were no skin rashes. The extremities were warm.

Upon admission in critical condition, the patient underwent cardiac monitoring and sequential respiratory support, including endotracheal intubation with mechanical ventilation (January 28 to 29), mask oxygen therapy (January 29 to 30), and nasal cannula oxygen (January 30 to February 2). On January 31, bedside flexible bronchoscopy for foreign body removal was conducted under sedation. The procedure revealed a nut shell-like reflective foreign body at the right lower lobe basilar segment orifice, with minimal granulation tissue. Despite multiple attempts using a foreign body basket (Airway M00513200), forceps, and biopsy forceps, only small nut shell fragments were retrieved. A large pine nut shell fragment remained lodged in the basilar segment, precluding complete removal (Figure 2A).

Under general anesthesia in the operating room, flexible bronchoscopy was performed. The right lower lobe basilar segment foreign body was fragmented via multiple holmium laser ablations, with thick secretions evacuated and saline lavage administered. The holmium laser was set at 0.5 J/pulse with a frequency of 10 Hz and a pulse width of 200 μs. Single laser cauterization was controlled for 1~2 s each time, with a total cumulative cauterization duration of approximately 8~10 min by intermittent operation. To prevent thermal damage to the airway mucosa, multiple safety measures were adopted during the operation: continuous normal saline irrigation was applied at the operation site to reduce local temperature, a safe distance of ≥2 mm was maintained between the laser fiber tip and the airway mucosa, real-time monitoring of mucosal color was performed via flexible bronchoscopy, and the operation was stopped immediately if mucosal congestion aggravated. Large fragments dislodged into the right main bronchus using biopsy forceps and a 4.0-mm balloon catheter. In supine position with shoulder elevation, rigid bronchoscopy removed large pine nut shell fragments from the right main bronchus. Residual small fragments in the right lower lobe were retrieved with a foreign body basket via flexible bronchoscopy. Complete bronchial inspection (lobar, segmental, and main bronchi) confirmed no residual foreign body. Partial mucosal injury and granulomatous hyperplasia were noted in the basilar segment (Figure 2B). Minor intraoperative bleeding was controlled with topical epinephrine. The retrieved foreign bodies were shown to her parent after the procedure, and the patient was safely transferred to the ward.

After surgery, the patient underwent tracheal intubation with mechanical ventilation from February 3 to 4, followed by mask oxygen inhalation on February 4. On February 5, local anesthesia enabled bedside flexible bronchoscopy with alveolar lavage. Findings included marked congestion, edema, erosive necrosis, and partial mucosal detachment in the right lower lobe basilar segment bronchial mucosa, with lumen obstruction by necrotic mucosa and yellowish secretions. Saline lavage, suctioning, and foreign body basket retrieval removed sputum plugs and necrotic debris, improving lumen patency (Figure 2C). Subsequently transferred to the Respiratory Medicine Department, the patient received piperacillin sulbactam for anti-infection (January 28 to February 10), methylprednisolone sodium succinate for anti-inflammation (January 28 to February 6), and symptomatic support with ambroxol and aerosol inhalation.

The child was readmitted for reexamination on February 24. A chest X-ray showed increased lung markings (Figure 1C). Flexible bronchoscopy revealed improved but persistent congestion, edema, and erosive necrosis in the right lower lobe basilar segment bronchial mucosa compared to prior findings (Figure 2D). On May 5 follow-up, flexible bronchoscopy identified stenosis at the orifices of B9 and B10 bronchi in the right lower lobe basilar segment, precluding passage of a 3.0-mm outer diameter bronchoscope. Serial dilation with 3.5-mm and 4.0-mm balloons (30-s inflations, 3 times each) allowed smooth passage of a 3.7-mm outer diameter bronchoscope (Figure 2E).

Discussion

This case report of a pediatric patient with FBA of a pine nut shell highlights the multifaceted and intricate nature of managing such critical situations. The integrated use of holmium laser cauterization, rigid bronchoscopy and flexible bronchoscopy, followed by balloon dilation for bronchial stenosis, offers valuable insights into the evolving landscape of therapeutic strategies for pediatric FBA.

The initial application of the holmium laser cauterization for cauterization of the pine nut shell is an innovative approach. In cases where foreign bodies are firmly embedded and surrounded by inflamed or granulated tissues, traditional mechanical extraction methods can pose risks of airway injury or incomplete removal [8,9]. The holmium laser cauterization provides a precise and minimally invasive means to fragment and vaporize parts a foreign body, reducing its size and facilitating subsequent removal. This technique minimizes mechanical trauma to the airway mucosa and addresses the potential for tissue adhesion to the foreign body, thereby improving the success rate of extraction. However, its use in pediatric patients requires meticulous control due to the delicate nature of the pediatric airway, and close monitoring for potential thermal injury to surrounding tissues is essential.

The combination of rigid and flexible bronchoscopy in this case exemplifies the complementary advantages of these 2 modalities. Rigid bronchoscopy, known for its superior visualization, stability, and ability to provide mechanical support, is the cornerstone for the initial exploration and extraction of foreign bodies in the pediatric airway. Its robust design allows for the insertion of larger instruments, such as forceps, which are crucial for grasping and removing relatively large foreign bodies such as the pine nut shell involved in the present case [10]. Flexible bronchoscopy offers enhanced maneuverability and the capacity to access peripheral airways, enabling a more comprehensive assessment of the airway tree [11]. In this case, the flexible bronchoscopy was employed in conjunction with the rigid bronchoscopy to ensure that no residual fragments of the foreign body remained in the more distal bronchi, thereby minimizing the risk of recurrent obstruction or infection. This integrated approach maximizes the effectiveness of foreign body removal while minimizing the potential for missed lesions [12].

The subsequent finding of bronchial stenosis at the site of the previous foreign body impaction during the follow-up flexible bronchoscopy underscores the long-term sequelae that can occur after foreign body aspiration. The development of bronchial stenosis in this case was a combined result of foreign body retention duration, airway mucosal damage, and the mild thermal effect of laser application. First, the pine nut shell was retained in the airway for about 12 days, causing persistent inflammatory stimulation to the bronchial mucosa and laying the pathological foundation for mucosal hyperplasia and stenosis. Second, mechanical compression by the impacted foreign body and mild mucosal laceration during foreign body retrieval led to abnormal epithelial repair and fibrous tissue hyperplasia of the airway mucosa, which was the main cause of bronchial stenosis. Third, although strict thermal damage prevention measures were taken, the mild thermal effect of the holmium laser slightly aggravated the local inflammatory response of the mucosa and accelerated the proliferation of fibrous tissue, which was an additional factor causing stenosis. This case of delayed bronchial stenosis occurring 2 months after foreign body removal was consistent with the conclusion of Köse et al (2019) [14], who reported that about 15% of pediatric FBA patients developed bronchial stenosis 1~3 months after foreign body removal, mostly in the segmental bronchi where the foreign body was impacted. The sequential balloon dilation with 3.5 mm and 4.0 mm in this case was in line with the view of Liang et al (2019) [15] that “gradually increasing balloon diameter can reduce the risk of mucosal laceration”. In addition, the pathological basis of stenosis in this case was inflammatory fibrous tissue hyperplasia, which was the same as the main pathological type of post-FBA stenosis in children reported by Xu et al (2022) [10]. Compared with the stenosis incidence of about 22% after simple mechanical foreign body removal reported by Swanson et al (2002) [11], the combined technique of holmium laser fragmentation and sequential balloon dilation in this study effectively reduced the risk of post-FBA stenosis and provided a new clinical treatment option. The presence of a foreign body, especially for an extended period, can induce a series of inflammatory responses in the airway mucosa, leading to tissue remodeling and subsequent stenosis. Balloon dilation is as a valuable therapeutic option in such scenarios. By mechanically expanding the narrowed bronchial lumen, balloon dilation aims to restore normal airway caliber and function. An individualized long-term follow-up strategy was formulated for this pediatric patient to monitor the prognosis of airway stenosis. Short-term follow-up (1, 2, and 4 weeks after surgery) included bedside flexible bronchoscopy and chest X-ray to monitor mucosal repair and secretion drainage. Medium-term follow-up (1, 2, and 3 months after surgery) included high-resolution chest CT and bronchoscopy to evaluate airway patency and intervene in time if a stenosis precursor was found. Long-term follow-up (6, 12, and 24 months after surgery) included chest CT and pulmonary function test to monitor the recovery of pulmonary ventilation function. The follow-up endpoint was set as 24 months after surgery, and regular follow-up could be terminated if there were no stenosis recurrence and pulmonary function returned to normal, with only annual routine physical examination required. This minimally invasive procedure has been shown to effectively relieve airway obstruction, improve pulmonary ventilation, and reduce the risk of secondary respiratory complications such as atelectasis and recurrent pneumonia [13,14]. However, it is not without risks. Complications, including airway perforation, mucosal tearing, and recurrence of stenosis, need to be carefully considered. Long-term follow-up with repeated bronchoscopic examinations is necessary to monitor the stability of the airway and the effectiveness of the dilation procedure [15].

This case also emphasizes the importance of a comprehensive and individualized treatment plan in pediatric foreign body aspiration. Each patient can present with unique anatomical characteristics, the nature of the foreign body, and the duration and location of impaction. Therefore, a tailored approach that combines various therapeutic modalities, as demonstrated in this case, is often required to achieve the best outcomes. Moreover, continuous surveillance and follow-up are integral components of management, as they enable the early detection and intervention for potential complications, such as airway stenosis. Current clinical approaches for determining bronchoscopy indications in pediatric FBA advocate hierarchical management to reduce unnecessary invasive interventions [16]. Emergency bronchoscopy is indicated for children with a clear history of foreign body aspiration combined with respiratory symptoms or abnormal imaging findings. A 24~48 h clinical observation period is recommended for those with only a suspicious aspiration history but no symptoms and normal imaging. Minimally invasive exploration with flexible bronchoscopy is used for asymptomatic children with imaging suggesting airway foreign bodies. The patient in this study had a clear history of pine nut aspiration combined with progressive dyspnea, cyanosis, and abnormal chest CT findings, which was a strong indication for emergency bronchoscopy, and the intervention was in line with the latest clinical guidelines.

Conclusions

In conclusion, we present a challenging case of a child with a foreign body lodged in the airway complicated by bronchial stenosis. Our experience demonstrates that holmium laser-assisted bronchoscopy combined with balloon dilation is a feasible and effective, minimally invasive therapeutic option for managing post-removal bronchial stenosis in this setting. Caution should be exercised when interpreting the findings of this study, as it is limited to a single case report. Further validation through large-scale, prospective clinical studies is required to confirm the generalizability and long-term efficacy of this combined therapeutic approach before it can be widely integrated into standard clinical practice guidelines.