Norihito Okumura

Intrathoracic tracheal reconstruction with a collagen-conjugated prosthesis: Evaluation of the efficacy of omental wrapping

Reconstructions of the intrathoracic trachea in 24 dogs were done with the use of 50 mm long collagen-conjugated tracheal prostheses. Omental wrapping was also done in 14 of the dogs (omentopexy group) to evaluate the efficacy of this option in comparison with results in the other 10 dogs (control group). All 24 dogs had uneventful postoperative courses and were killed at 4 weeks or 3, 6, or 12 months after the operation. Better epithelialization and fewer complications, such as mesh exposure and luminal stenosis, were observed in the omentopexy group than in the control group. Angiography and analysis of regenerated blood vessels revealed that vessel ingrowth had started within 4 weeks and that vessel formation reached its maximal point within 6 to 12 months in the omentopexy group. In contrast, revascularization of the subepithelial region in the control group was poor even after 3 months, and vessel formation continued for as long as 12 months. The differences between the two groups were considered to be mainly a result of the speed of blood vessel ingrowth into the regenerated mucosa. We conclude that our prosthesis can be used safely for intrathoracic tracheal reconstruction and that omental wrapping is a useful supplementary method that reduces the occurrence of complications.

Evaluation of the new TNM staging system proposed by the International Association for the Study of Lung Cancer at a single institution

OBJECTIVE The seventh TNM Classification of Malignant Tumours will be published in 2009. The International Association for the Study of Lung Cancer has proposed a revision of the current pathologic staging system. We illustrated the effects of this new system and pointed out potential problems using a retrospective study of surgical cases of non-small cell lung cancer at our institution. METHODS Subjects were 1532 patients for whom current pathologic staging was possible. These data were migrated into the new staging system. The numbers of patients at various stages determined by using the current and new staging systems were, respectively, as follows: IA (n = 700, n = 700), IB (n = 338, n = 249), IIA (n = 49, n = 164), IIB (n = 129, n = 116), IIIA (n = 204, n = 234), IIIB (n = 77, n = 17), and IV (n = 35, n = 52). Prognoses were compared by using the current and the new systems. RESULTS By using the new staging system, 5-year survivals by T classifications were as follows: T1a, 82.6%; T1b, 73.3%; T2a, 63.5%; T2b, 50.1%; T3, 40.6%; and T4, 34.6%. There were significant differences between the new T1a and T1b (P = .0026), T1b and T2a (P = .0027), and T2a and T2b (P = .0062) classifications. In the current system 5-year survivals based on pathologic stages were as follows: IA, 84.8%; IB, 72.9%; IIA, 53.8%; IIB, 53.7%; IIIA, 31.8%; IIIB, 34.0%; and IV, 27.1%. There were significant differences between stages IA and IB (P < .0001) and stages IIB and IIIA (P = .0006). In the new system these were as follows: IA, 84.8%; IB, 75.2%; IIA, 62.4%; IIB, 52.1%; IIIA, 32.4%; IIIB, 15.2%; and IV, 30.6%. There were significant differences between stages IA and IB (P = .0004), IB and IIA (P = .0195), IIA and IIB (P = .0257), IIB and IIIA (P = .0040), and IIIA and IIIB (P = .0399). CONCLUSION Although the outcomes for stages IIIB and IV were reversed, the new pathologic staging system was considered valid based on our single-institution evaluation.

Postrecurrence survival in patients with stage I non-small cell lung cancer

OBJECTIVE Postoperative recurrence is a major obstacle to achieving a cure and long-term survival in patients with non-small lung cancer. However, prognostic factors and the efficacy of therapy after recurrence remain controversial. We evaluated the clinical outcomes of patients with resected lung cancer for postrecurrence prognostic factors. METHODS Patients who underwent complete resection with systematic lymph node dissection for stage I non-small cell lung cancer were selected. Cases of low-grade malignancy, preoperative therapy, history of previous malignancy or death within 30 days of operation were excluded. A total of 397 patients were retrospectively reviewed. RESULTS Out of 87 patients who had recurrence after surgery, 45 had symptoms at the initial recurrence. The initial recurrent site was local in 30 patients and distant in 57. Single-site recurrence was detected in 48 patients and multiple-site recurrence was seen in 39. The recurrent site was the ipsilateral thorax in 49 patients, the contralateral thorax in 32, the cervico-mediastinum in 15, brain in 12 and bone in 11. Surgery was performed in 20 patients, whereas non-surgical therapy was performed in 55 (chemotherapy, 16; radiation therapy, 33; chemo-radiation therapy, 6). Prognostic analysis of factors related to recurrent status demonstrated that symptoms at the initial recurrence, cervico-mediastinal metastasis, liver metastasis and postrecurrence therapy were significant prognostic factors in both univariate and multivariate analysis. CONCLUSIONS Symptoms at the initial recurrence, cervico-mediastinal metastasis and liver metastasis were worse prognostic factors after recurrence. Postrecurrence therapy for the initial recurrence may prolong survival after recurrence.

Long-term follow-up of the experimental replacement of the esophagus with a collagen-silicone composite tube

This study investigated ways of preventing late stenosis after replacing the esophagus with a prosthetic device and increasing survival time in an animal model. In a previous study, the authors induced neoesophageal formation and re-epithelialization at an early stage, although stenosis in the chronic stage remained a problem, and long-term survival was prevented. The authors developed an artificial esophagus made from a collagen-silicone composite tube. The silicone tube (25 mm in diameter, 50 mm long, and 1 mm thick) was covered with collagen sponge (5 mm thick). The collagen sponge was intended to be replaced by host tissue, leading to neoesophageal regeneration. The authors thought stenosis was caused primarily by poor regeneration of submucosal tissue, rather than reepithelialization. Thus, they examined the grade of stenosis relative to the time the stent became dislodged. They concluded that the occurrence of stenosis after anastomosis depends upon the duration of stenting and that stenosis did not develop when the portion replaced by the artificial esophagus was stented for at least 4 weeks.

Relationship between stenting time and regeneration of neoesophageal submucosal tissue

The authors developed a new type of artificial esophagus consisting of an inner silicone tube and an outer non antigenic collagen tube. The novel feature of this artificial esophagus is that the main part of the prosthesis is replaced by host tissue. In a previous study, the authors found that no stenosis of the artificial esophagus developed when the replacement part was stented for more than 4 weeks. It was considered that this stenosis was caused mainly by poor regeneration of submucosal tissue, rather than by the grade of reepithelialization. In this study, it was found that, in cases in which the stent dropped out within 3 weeks, fibrous tissue was noted beneath the neoesophageal epithelium. In such cases, neither muscle layers nor submucosal glands regenerated beneath the neoesophageal epithelium after replacement. However, in cases in which the stent dropped out more than 4 weeks after surgery, the neoesophagus was covered with a polylayer of squamous epithelium and had normal esophageal glands and a muscle layer. Therefore, it was concluded that muscle tissue and esophageal glands were able to regrow in the neoesophagus when the portion replaced by the artificial esophagus was stented for at least 4 weeks.

Experimental reconstruction of the intrathoracic trachea using a new prosthesis made from collagen grafted mesh

Intrathoracic tracheal replacement was performed in dogs using a tracheal prosthesis we had constructed from mesh. The prosthesis consists of Marlex mesh (polypropylene) reinforced with a continuous polypropylene spiral, and is grafted and coated with pig collagen (Types I and III). Complete surgical resection of the mediastinal trachea was performed in seven adult mongrel dogs. In 1 dog, a 4 tracheal ring segment (2 cm) was resected and replaced with a 3 cm prosthesis, and in 6 dogs, a 7 to 8 tracheal ring segment (4 cm) was resected and replaced with a 5 cm prosthesis. In the latter six dogs, a silicone tube was temporarily inserted into the replacement, and removed by bronchoscopy one month after surgery. In one dog that received a 4 cm replacement, we added omentopexy around the reconstructed trachea. The prostheses in all dogs were promptly infiltrated by surrounding tissue and incorporated by the host trachea. No dehiscence or air leakage was observed after surgery. Mild luminal stenosis was evident in one dog, and partial exposure of the mesh (ulceration) was observed in five dogs within an observation period of 3 to 26 months. However, in the dog that received omentopexy after tracheal reconstruction, no stenosis or ulceration was observed, and the luminal surface seemed lustrous even after 6 weeks. Formation of respiratory epithelium, which lined the prosthetic lumen, was seen to various degrees: in the 2 dogs killed 12 months and 26 months after surgery, confluent epithelization was confirmed histologically from the upper to the lower anastomosis of the prosthesis. The tracheal prosthesis is useful for the repair of intrathoracic tracheal defects and shows promise for clinical application with further investigation.

Surgical treatment for non-small cell lung cancer in octogenarians--the usefulness of video-assisted thoracic surgery.

The purpose of this study was to investigate whether surgical treatment for non-small cell lung cancer (NSCLC) confers a survival benefit in octogenarians, and whether video-assisted thoracic surgery (VATS) is effective in terms of postoperative morbidity, mortality, and quality of life (QOL). Among 1684 patients with primary NSCLC who underwent pathologically complete resection, 95 were octogenarians. Operation was performed by the VATS approach (VATS group, n=58) or the standard thoracotomy (ST group, n=37). Although postoperative cardiopulmonary complications occurred in 20 cases (21.1%), all were manageable. In the ST group cardiopulmonary complications occurred more frequently than in the VATS group (P=0.030). The overall 5-year survival rate of the 95 octogenarians, including deaths from all causes, was 54.4%. The overall 5-year survival rate of patients with stage IA disease was 65.2%. These outcome data were not significantly worse than those for patients aged 79 years or under (P=0.136). There was no significant difference in overall 5-year survival rates between the ST group and the VATS group (P=0.144). The VATS approach for pulmonary resection is recommended for octogenarians with NSCLC. Surgical resection is the optimal treatment for stage IA NSCLC, and therefore, advanced age is not a contraindication for curative resection.

Spontaneous rupture of mediastinal cystic teratoma into the pleural cavity : Report of two cases and review of the literature

The authors report on two female patients aged 12 and 14 years, who spontaneously developed a rupture of benign mediastinal cystic teratoma into the right pleural cavity. They presented with acute onset of severe chest pain and respiratory distress. The tumors were completely resected by thoracotomy. The serum and pleural fluid levels of carcinoembryonic antigens, CA-125 and CA19-9 were invariably elevated, then decreased to normal range after the surgical resection. Rapid diagnosis of this extremely rare complication is important because it may progress to a life-threatening condition.

A Novel Bioabsorbable Monofilament Surgical Suture Made From (ε -Caprolactone, L-Lactide) Copolymer

A Novel monofilament bioabsorbable sutures was made from a copolymer of e-caprolactone and L-lactide (Poly(CL-LA)). The Composition weight ratio of L-lactide: e-caprolactone was 85: 15. Initial tensile strength of the 5-0 suture was 838 ±72 gf (knot-pull 600 ±60 gf). An in vivo degradation test using rabbits showed: a poly(CL-LA) suture retains its strength for longer periods than other synthetic monofilament absorbable sutures such as MAXON®and PDS®. %Retention of tensile strength at 4 week was Poly(CL-LA) 83 ±13%, MAXON®36 ±9% PDS®50 ± 15%. At 8 weeks the Poly(CL-LA) was 38.2%, though the MAXON®and PDS®were 0%. The tissue reaction of this suture was not remarkable at any interval. At one year, the Poly(CL-LA) fiber was replaced with Collagen deposition.

Rapidly expanding extrapleural hematoma

We present a rare case of extrapleural hematoma due to chest trauma in an anticoagulated male patient. Chest computed tomography revealed multiple left rib fractures and a D-shaped opacity in the upper left side of the thorax suggesting extrapleural hematoma, which was caused from continuous bleeding. His past history included alcoholic liver cirrhosis, which caused thrombocytopenia and coagulopathy. Therefore, the hematoma was expanding, causing circulatory and ventilatory disturbance and severe anemia despite the difficulty of expanding in the extrapleural space. As the bleeding did not stop, even after intercostal artery angiography with embolization was performed, surgical treatment was undertaken to control the bleeding and evacuate the huge hematoma. The problems associated with the diagnosis and treatment of an extrapleural hematoma are discussed in the light of this case.