A 44-year-old man (body mass index 39 kg/m²) was evaluated for chest pain and dyspnoea with a two-year history. After assessment by the pulmonology, cardiology, and neurology departments, a diagnosis of idiopathic left diaphragmatic relaxation was made, and the patient was referred for thoracic surgery. His medical history was notable for suspected obstructive sleep apnoea syndrome (OSAS), managed with non-invasive mechanical ventilation (NIV). Physical examination was unremarkable.

A neurophysiological study and thoracic computed tomography scan (Figure 1) revealed a serious elevation of the left hemidiaphragm and herniation of abdominal contents into the thorax, including stomach, spleen, and colon splenic flexure, occupying approximately 50% of the left hemithorax and causing right mediastinal shift, with 20% of abdominal viscera displaced into the thorax according to Sabagg’s formula [13]. Preoperative preparation focused on prehabilitation with respiratory physiotherapy.

Given the size of the defect, adjuvant therapy was performed with botulinum toxin injection following the Smoot technique [14], without complications.

Four weeks later, a left diaphragmatic plication was performed via posterolateral thoracotomy, using non-absorbable monofilament barbed sutures and reinforced with a Gore- Tex® mesh. Intraoperative findings confirmed significant diaphragmatic laxity, with the dome of the diaphragm reaching the level of the bronchial carina. A pleural drain and an epidural catheter were placed for postoperative management.

The patient was extubated in the operating room and transferred to the postoperative recovery unit, where he remained for 4 days, hemodynamically stable, eupnoeic, and without need for supplemental oxygen. Intra-abdominal pressure was monitored, with values of 10 mmHg preoperatively, 11 mmHg at the end of surgery, and less than 15 mmHg over the subsequent days. The epidural catheter was removed at 72 h, the pleural drain removed on postoperative day 5, and the patient was discharged on day 6.

At the six-month follow-up, the patient reported significant improvement in quality of life, including the ability to tolerate the supine position, which had previously been intolerable. He demonstrated good respiratory function, and a follow-up chest radiograph (Figure 2) showed no elevation of the left hemidiaphragm. At twelve months, the patient remained asymptomatic and recurrence-free.

A 63-year-old woman (body mass index 35 kg/m²) was evaluated for dyspnoea and digestive symptoms of 2 years’ duration. After being evaluated by the pulmonology department, idiopathic left diaphragmatic relaxation was diagnosed, and the patient was referred for thoracic surgery. Her medical history included being a former smoker for 20 years, and she was diagnosed with severe OSAHS (obstructive sleep apnoea-hypopnea syndrome). The physical examination was normal.

A chest CT (Figure 3) scan revealed a severe elevation of the left hemidiaphragm and herniation of abdominal contents into the thorax, including stomach, spleen, and colon splenic flexure, with a percentage of herniated viscera of 23% according to Sabagg’s formula [13], which occupied more than half of the left hemithorax. It is associated with compressive atelectasis and a moderate contralateral mediastinal shift. No image of a diaphragmatic defect was observed. Preoperative preparation focused on prehabilitation with chest physiotherapy. Given the size of the defect, adjuvant therapy was performed with botulinum toxin injection following the Smoot technique [14], without complications.

Four weeks later, a left diaphragmatic plication was performed via posterolateral thoracotomy, using nonabsorbable monofilament barbed sutures reinforced with Gore- Tex® mesh. Intraoperative findings confirmed significant diaphragmatic laxity, with the dome of the diaphragm reaching the main carina. A pleural drain and an epidural catheter were placed for postoperative management.

The patient was extubated in the operating room and transferred to the Postoperative Recovery Unit, where she remained hemodynamically stable, eupnoeic, and without the need for supplemental oxygen for 2 days. Intra-abdominal pressure was monitored, with values of 12 mmHg preoperatively, 12 mmHg at the end of surgery, and less than 15 mmHg in the following days. The epidural catheter was removed 72 h later, the pleural drain was removed on the fourth postoperative day, and the patient was discharged on the fifth day.

At a six-month follow-up, the patient reported a significant improvement in her quality of life, with improved respiratory function and digestive symptoms. At 12 months, the patient remained asymptomatic and without recurrence. The follow-up postoperative X-ray showing decreased—but not complete resolution of—left hemidiaphragm elevation compared to the preoperative state, which did not show an elevated diaphragm (Figure 4).

A 45-year-old man (body mass index 30 kg/m²) was evaluated for mild haemoptysis, moderate exertional dyspnoea, episodes of central chest tightness, and exercise intolerance. After being evaluated by the pulmonology department, he was diagnosed with idiopathic left diaphragmatic relaxation and referred for thoracic surgery. His medical history included being a former smoker for 2 months, asthmatic bronchitis in childhood, and admission to the emergency department in November 2022 for extensive deep vein thrombosis in the right lower extremity and acute pulmonary thromboembolism in the inferior lobar pulmonary artery and left basal segmental pulmonary arteries. Physical examination was normal.

A chest CT scan showed left lung volume loss due to a large diaphragmatic elevation with intra-abdominal visceral contents in the chest and a right-sided mediastinal shift (Supplementary Figure 1). Preoperative preparation focused on prehabilitation with respiratory physiotherapy. Given the size of the defect, adjuvant therapy was performed with botulinum toxin injection following the Smoot technique [14], without complications.

Four weeks later, diaphragmatic plication was performed with a non-absorbable barbed suture without the need for reinforcing mesh using video-assisted thoracoscopy. A pleural drain and an epidural catheter were placed for pain control. The patient was extubated in the operating room and transferred to the postoperative recovery unit, where he remained for 24 h, hemodynamically stable, eupnoeic, and without the need for supplemental oxygen. Intra-abdominal pressure was monitored, with values of 13 mmHg at the end of surgery. The epidural catheter and pleural drain were removed 48 h later, and the patient was discharged on the third day.

At a six-month follow-up, respiratory function improved without dyspnoea or recurrence (Supplementary Figure 2).