Emmanuel Martinod

Long-term evaluation of the replacement of the trachea with an autologous aortic graft

BACKGROUND Tracheal reconstruction after extensive resection remains a challenge in thoracic surgery. The goal of this experimental study was to analyze the long-term evolution of tracheal replacement using an autologous aortic graft. METHODS In 21 sheep, a 5-cm segment of the cervical trachea was replaced by a segment of the descending thoracic aorta that was reconstructed to a prosthetic graft. Because of the airway collapse reported in a previous series, a permanent (n = 13) or temporary (n = 8) stent was systematically placed in the lumen of the graft. Clinical, bronchoscopic, and histologic examinations were performed up to 3 years after implantation. RESULTS All animals survived the operation with no paraplegia. In the group with a permanent stent, three complications occurred: one stent displacement, one laryngeal edema, and one infection. Stent removal was tolerated after 6 months in the group with a temporary stent. Histologic examination showed a progressive transformation of the arterial segment into first extensive inflammatory tissue with a squamous epithelium, and after 6 to 36 months well-differentiated tracheal tissue including a continuous mucociliary epithelium and regular rings of newly formed cartilage. CONCLUSIONS An autologous aortic graft used as a substitute for extensive tracheal replacement in sheep remained functional for periods up to 3 years. The progressive transformation of the graft into a structure resembling tracheal tissue seems to be a key factor in long-term patency. The mechanism of this regenerative process and the possibility of using arterial homografts, which would make clinical application easier, remain to be evaluated.

Role of Videothoracoscopy in Chest Trauma

BACKGROUND The aim of this study was to evaluate videothoracoscopic procedures in the setting of chest trauma. METHODS We retrospectively analyzed our experience of videothoracoscopy in patients with either blunt trauma or penetrating thoracic injuries. RESULTS Forty-three procedures involving 42 patients were performed between July 1990 and April 1996. Indications for videothoracoscopy included suspected diaphragmatic injury (14 patients), clotted hemothorax (12), continued hemothorax (6), persistent pneumothorax (5), intrathoracic foreign body (4), posttraumatic chylothorax (1), and posttraumatic empyema (1 patient). Ten patients (24%) required conversion to thoracotomy. Two patients suffered postoperative pneumonia. There was one perioperative death. Mean hospital stay was 17 days; 21 days for patients with blunt trauma and 13 days for patients with penetrating injuries. There was no procedure-related complication. Videothoracoscopy allowed precocious discharge of patients suffering penetrating injuries and allowed faster recovery in the majority of patients suffering severe blunt trauma. CONCLUSIONS Videothoracoscopy appears to be a safe, accurate, and useful approach in selected patients with chest trauma. It is ideal for the assessment of diaphragmatic injuries, for control of chest wall bleeding, for early removal of clotted hemothorax, for treatment of empyema, for treatment of chylothorax, for treatment of persistent pneumothorax, and for removal of intrathoracic foreign body. However, we do not recommend the use of this technique in the setting of suspected great vessel or cardiac injury.

Management of superior sulcus tumors: experience with 139 cases treated by surgical resection.

BACKGROUND The management of non-small cell carcinomas of the lung involving the superior sulcus remains controversial. The goal of this retrospective study was to evaluate the role of surgery, radiotherapy, and chemotherapy for the treatment of superior sulcus tumors, to define the best surgical approach for radical resection, and to identify factors influencing long-term survival. METHODS Between 1983 and 1999, 139 patients underwent surgical resection of superior sulcus tumors in seven thoracic surgery centers. According to the classification of the American Joint Committee, 51.1% of cancers were stage IIB, 13.7% stage IIIA, 32.4% stage IIIB, and 2.9% stage IV. RESULTS The resections were performed with 74.1% using the posterior approach and 25.9% using an anterior approach. A lobectomy was accomplished in 69.8% of the cases and a wedge resection in 22.3%. Resection of a segment of vertebrae or subclavian artery was performed, respectively, in 19.4% and 18% of the cases. Resection was complete in 81.3% of cancers. The overall 5-year survival rate was 35%. Preoperative radiotherapy improved 5-year survival for stages IIB-IIIA. Surgical approach, postoperative radiotherapy, or chemotherapy did not change survival. CONCLUSIONS The optimal treatment for superior sulcus tumors is complete surgical resection. The surgical approach (anterior/posterior) did not influence the 5-year survival rate. Preoperative radiotherapy should be recommended to improve outcome of patients with a superior sulcus tumor.

Tracheal Replacement With Cryopreserved, Decellularized, or Glutaraldehyde-Treated Aortic Allografts

BACKGROUND Seven years of experimental research provided a valuable tracheal substitute, the aortic allograft, which can promote the regeneration of epithelium and cartilage. In human application, both fresh and preserved aortic allografts could be used. The optimal method of aortic allograft preservation remains to be evaluated. This study assessed the use of cryopreserved, decellularized, or glutaraldehyde-treated aortic allografts as tracheal substitutes. METHODS Twenty-two sheep underwent tracheal replacement using cryopreserved (n = 10), decellularized (n = 7) or glutaraldehyde-treated (n = 5) allografts, supported by a temporary stent to prevent airway collapse. Aortic segments were retrieved at regular intervals up to 12 months after implantation to analyze the regenerative process. RESULTS All animals survived the operation. Major complications such as infection, stent migration, or obstruction were predominantly encountered in the decellularized group. The lack of major inflammatory response within the aortic graft observed in the glutaraldehyde group was associated with the absence of tracheal regeneration. Histologic examinations showed a progressive transformation of the aorta into a tracheal tissue comprising respiratory epithelium and cartilage only in the cryopreserved group. CONCLUSIONS This study demonstrated that regeneration of a functional tissue could be obtained after tracheal replacement with a cryopreserved aortic allograft. The regenerative process followed the same pattern as previously described for fresh allografts. Cryopreserved aortic allografts present major advantages: availability in tissue banks, permanent storage, and no need for immunosuppression. This offers a new field of perspectives for clinical application in patients with extensive tracheal cancer.

Thoracoscopic excision of mediastinal bronchogenic cysts: results in 20 cases

BACKGROUND We present our experience with thoracoscopic resection of mediastinal bronchogenic cysts in adults. METHODS From November 1990 to September 1993, 20 patients with mediastinal bronchogenic cysts were operated on by thoracoscopy. The average cyst size was 4.9 cm, and the largest diameter was 10 cm. Ten cysts were located in the middle mediastinum and 10 in the posterior mediastinum. Two cysts were complicated. RESULTS Thirteen bronchogenic cysts were resected completely by thoracoscopy. We had to convert thoracoscopy into thoracotomy because of bleeding in two cases and because of major adhesions to vital structures in five cases. There were no operative deaths and no postoperative complications. Mean hospital stay was significantly less in the completely thoracoscopically treated group. Long-term follow-up (range, 4.5 to 7.5 years) showed no late complications and no recurrence. CONCLUSIONS Preoperative complications, intraoperative injuries, and major adhesions to vital structures seem to be the only unfavorable conditions to thoracoscopic treatment of bronchogenic cysts. This study found encouraging results for thoracoscopic excision of mediastinal bronchogenic cysts in selected patients.

Tracheal Replacement With Cryopreserved Allogenic Aorta

BACKGROUND Radical resection of primary tracheal tumors may be challenging when more than one-half of the tracheal length is concerned. The present study evaluated the use of cryopreserved aortic allografts (CAAs) to replace long tracheal segments. METHODS Sixteen adult minipigs underwent tracheal replacement with a CAA. A silicone stent was used to splint the CAA for the first 12 months. Animals were followed-up using bronchoscopic evaluation and killed at predetermined times, for a period up to 18 months long. RESULTS Intense inflammation and progressive disappearance of typical histologic structures of the aorta were seen within the first 3 months. All animals studied for more than 3 months showed progressive transformation of the graft into a chimerical conduit sharing aortic and tracheal histologic patterns (eg, islands of disorganized elastic fibers/mature respiratory ciliated epithelium, respiratory glands, islets of cartilage). Stent removal was attempted after 12 months in 10 animals, and critical tracheal stenosis was found in six animals and moderate asymptomatic stenosis in four. Clinical course in these latter animals was uneventful until they were killed at 15 to 18 months. In situ hybridization showed that collagen2a1 mRNA was expressed in the cartilage islets at 1 year. Polymerase chain reaction analysis of the SRY gene demonstrated that the newly formed cartilage cells derived from the host. CONCLUSIONS CAA may be considered as a valuable tracheal substitute for patients with extensive tracheal tumors. Prolonged stenting will be probably mandatory for the clinical application of the procedure in humans.

18F-FDG PET-Derived Textural Indices Reflect Tissue-Specific Uptake Pattern in Non-Small Cell Lung Cancer

Purpose Texture indices (TI) calculated from 18F-FDG PET tumor images show promise for predicting response to therapy and survival. Their calculation involves a resampling of standardized uptake values (SUV) within the tumor. This resampling can be performed differently and significantly impacts the TI values. Our aim was to investigate how the resampling approach affects the ability of TI to reflect tissue-specific pattern of metabolic activity. Methods 18F-FDG PET were acquired for 48 naïve-treatment patients with non-small cell lung cancer and for a uniform phantom. We studied 7 TI, SUVmax and metabolic volume (MV) in the phantom, tumors and healthy tissue using the usual relative resampling (RR) method and an absolute resampling (AR) method. The differences in TI values between tissue types and cancer subtypes were investigated using Wilcoxon’s tests. Results Most RR-based TI were highly correlated with MV for tumors less than 60 mL (Spearman correlation coefficient r between 0.74 and 1), while this correlation was reduced for AR-based TI (r between 0.06 and 0.27 except for RLNU where r = 0.91). Most AR-based TI were significantly different between tumor and healthy tissues (pvalues <0.01 for all 7 TI) and between cancer subtypes (pvalues<0.05 for 6 TI). Healthy tissue and adenocarcinomas exhibited more homogeneous texture than tumor tissue and squamous cell carcinomas respectively. Conclusion TI computed using an AR method vary as a function of the tissue type and cancer subtype more than the TI involving the usual RR method. AR-based TI might be useful for tumor characterization.

Surgical resection of lung cancer in patients with underlying interstitial lung disease

BACKGROUND The association between interstitial lung disease (ILD) and an increased risk of developing lung cancer has been reported. The goal of this retrospective study was to determine the outcome of lung cancer resection among patients with ILD. METHODS Between January 1979 and March 1999, 27 patients with both lung cancer and ILD were identified. Seven patients with poor pulmonary function tests or distant metastases underwent medical treatment and were excluded from this study. Twenty patients treated by surgical resection were analyzed. RESULTS Various types of ILD such as sarcoidosis (n = 7), idiopathic interstitial pneumonia (n = 4), histiocytosis X (n = 4), pneumoconiosis (n = 4), and amiodarone-induced ILD (n = 1) were observed. Tumors were located in the peripheral part of the lung in 16 cases. The most frequent tumor cell types were squamous and adenocarcinoma. The resections consisted of lobectomy (n = 16), bilobectomy (n = 1), and pneumonectomy (n = 3). Most cancers were stage I (n = 10) or II (n = 6). There was no postoperative death. The postoperative course was uneventful in 16 cases. The majority of patients (70%) did not experience respiratory insufficiency during the follow-up period. The actuarial 2-year and 5-year survival rates were, respectively, 83.5% and 66.4%. CONCLUSIONS In this series, the long-term survival of patients who had lung cancer resection appeared to be not affected by the association with ILD. This could be explained by an adequate preoperative selection based on pulmonary function tests and a preferential choice for lobectomies. Thus, surgical resection should be offered to properly selected patients with lung cancer and underlying ILD.

Human Transplantation of a Biologic Airway Substitute in Conservative Lung Cancer Surgery

BACKGROUND Pneumonectomies for lung cancer are associated with a high postoperative mortality, especially when right-sided, after neoadjuvant radiochemotherapy, and in patients over 70 years of age. Preliminary studies in our laboratory have shown that aortic grafts could be valuable airway substitutes. We report the first human bronchial transplantation of a cryopreserved aortic allograft used as a biologic airway substitute to prevent a pneumonectomy for lung cancer. METHODS The procedure was performed in a high-risk 78-year old patient with an extensive right bronchopulmonary malignant tumor pretreated with chemotherapy. After a complete resection of the lung cancer using an upper bilobectomy with lymph node removal, mobilization procedures did not allow for a primary end-to-end bronchial anastomosis. A stent-supported cryopreserved aortic allograft from a certified tissue bank was interposed to restore the bronchial continuity with sparing of the lower lobe. RESULTS The postoperative course was eventful for a supraventricular arrhythmia leading to mild pulmonary edema that resolved using standard medical therapy, and a right lower lobe atelectasis with bacterial colonization that required fiberoptic bronchoscopies in addition to antibiotic treatment. A 1-year postoperative evaluation found a well-functioning reimplanted lower lobe with no complications related to the cryopreserved aortic allograft or the stent. The patient recovered to his baseline activity with a satisfying health-related quality of life. CONCLUSIONS We demonstrate the feasibility of this surgical innovation to prevent the high-risk procedure of pneumonectomy in a single case. If confirmed in larger series of selected patients, it could bring new perspectives in conservative lung cancer surgery.

Métaplasie de tissu aortique en tissu trachéal. Perspectives chirurgicales

Abstract Tracheal reconstruction after extensive resection remains an unsolved surgical problem. Numerous attempts have been made using tracheal grafts or prosthetic conduits with disappointing results. In this study, we propose a new alternative using an aortic autograft as tracheal substitute. In a first series of experiments, a half circumference of two rings was replaced with an autologous carotid artery patch. In a second series, a complete segment of trachea was replaced with an autologous aortic graft supported by an endoluminal tracheal stent. No dehiscence or stenosis was observed. Microscopic examinations at 3 and 6 months showed the replacement of the aortic tissue by tracheal tissue comprising neoformation of cartilage and mucociliary or non-keratinizing metaplastic polystratified squamous epithelium. Although these results need to be confirmed by a larger series of experiments, they showed that a vascular tissue placed in a different environment with a different function can be submitted to a metaplastic transformation which tends to restore a normal structure adapted to its new function. These remarkable findings offer new perspectives in tracheal reconstruction in human.