Cross-linked poly(gamma-glutamic acid) attenuates pleural and chest wall adhesions in a mouse thoracotomy model.

BACKGROUND: Cross-linked poly(gamma-glutamic acid) (XL) is derived from a naturally occurring biodegradable polymer produced by Bacillus subtilis. In the present study, we compared the efficacy of XL in preventing adhesion formation after thoracotomy in mice with Seprafilm (SEP), which is currently the most commonly applied adhesion prevention material. METHODS: Left thoracotomy was done. Adhesion between the lung and the thoracotomy site (Lu groups), or between the thoracotomy site and the overlying chest muscles (Mu groups), was evaluated in separate groups of animals. In the Lu-XL group (n = 12) and the Mu-XL group (n = 12), approximately 20 mg of XL was applied as powder. In the Lu-SEP group (n = 12) and Mu-SEP group (n = 12), a 5 × 3 mm SEP sheet was applied. Nothing was applied in the Lu-NON group (n = 12) and the Mu-NON group (n = 12). After 7 and 14 days, the respective adhesions were scored and compared. RESULTS: The adhesion score was significantly lower in the Lu-XL group (0.5 ± 0.9) in comparison to the Lu-NON group (3.8 ± 0.5) and the Lu-SEP group (2.2 ± 0.8; p < 0.002), and in the Mu-XL group (0.8 ± 0.7) in comparison to the Mu-NON group (3.8 ± 0.4) and the Mu-SEP group (2.5 ± 0.8; p < 0.001). These differences were similar also at 14 days. CONCLUSION: It was suggested that the antiadhesive effect of XL was superior to SEP in this particular model of thoracotomy in mice.

Sentinel node microscopic metastasis detected after segmentectomy for lung cancer followed by completion lobectomy: two case reports.

We performed sentinel node identification using radioisotopic and/or dye techniques to determine the final indication after segmentectomy in cases with non-small cell lung cancer. Sentinel nodes were examined using intraoperative frozen sections stained with hematoxylin and eosin. We present 2 cases with completion lobectomy performed 7 and 11 days after segmentectomy because immunohistochemical staining of the sentinel nodes showed the presence of microscopic metastases that were not detected by the examination of intraoperative frozen sections.

Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography.

AIM: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs. MATERIALS AND METHODS: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring

Class A scavenger receptor (CD204) attenuates hyperoxia-induced lung injury by reducing oxidative stress.

To clarify the role of macrophage class A scavenger receptors (SR-A, CD204) in oxidative lung injury, we examined lung tissue of SR-A deficient (SR-A(-/-)) and wild-type (SR-A(+/+)) mice in response to hyperoxic treatment. Protein levels of bronchoalveolar lavage fluid (BALF) and pulmonary oedema (wet : dry weight ratios) were higher in SR-A(-/-) mice than those in SR-A(+/+) mice. Cumulative survival was significantly decreased in SR-A(-/-) mice. However, there were no differences in BALF macrophage and neutrophil count between the two groups. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that messenger RNA (mRNA) levels of the inducible nitric oxide synthase (iNOS) were increased during hyperoxic injury, and this increase was more prominent in SR-A(-/-) mice. Expression levels of iNOS in alveolar macrophages after hyperoxia in vivo and in vitro were higher in SR-A(-/-) macrophages compared with SR-A(+/+) macrophages. Immunohistochemistry using anti-nitrotyrosine antibodies revealed distinctive oxidative stress in the injured lung in both groups, but it was more remarkable in the SR-A(-/-) mice. After hyperoxic treatment, pulmonary mRNA levels of tumour necrosis factor-alpha(TNF-alpha) were elevated more rapidly in SR-A(-/-) mice than in SR-A(+/+) mice. Together these results suggest that SR-A expression attenuates hyperoxia-induced lung injury by reducing macrophage activation.

Impact of additional pleurodesis in video-assisted thoracoscopic bullectomy for primary spontaneous pneumothorax.

BACKGROUND: Bullectomy for primary spontaneous pneumothorax has been associated with high postoperative recurrence rates when video-assisted thoracoscopic surgery (VATS) has been used rather than thoracotomy. The aim of this study was to evaluate the efficacy and identify the disadvantages, if any, of adding pleurodesis to VATS bullectomy to prevent recurrent pneumothorax. METHODS: Fifty-three patients who underwent VATS bullectomy with additional pleurodesis for pneumothorax after November 1996 and 50 who underwent VATS bullectomy alone before October 1996 were compared retrospectively in terms of intraoperative factors and postoperative chest pain, pulmonary function, and pneumothorax recurrent rates. Pleurodesis was achieved by electrocauterizing the upper surface of the parietal pleura in a patchy fashion. RESULTS: There were no significant differences between the additional pleurodesis group and the bullectomy alone group in terms of age, sex, operating time, intraoperative bleeding, number of resected bullae, duration of chest drainage, or volume of fluid drained. Postoperative chest pain and pulmonary function were also similar in both groups. A recurrent pneumothorax occurred in one patient (1.9%) in the additional pleurodesis group; this recurrence rate was significantly lower than that for the bullectomy alone group (eight patients, 16%; p = 0.029). Although the mean postoperative follow-up period was considerably shorter in the additional pleurodesis group (38 months [range, 26-49]) than in the bullectomy alone group (63 months [range, 50-72] ), eight (89%) of all nine recurrences occurred within 26 months of surgery-i.e., within the minimum follow-up period for the additional pleurodesis group. CONCLUSIONS: Pleurodesis is a minimally invasive technique that is effective in preventing postoperative recurrences of pneumothorax when added to VATS bullectomy. Additional pleurodesis has no disadvantages vs bullectomy alone in terms of worsening postoperative chest pain or pulmonary function.

A case of multiple atypical adenomatous hyperplasia of the lung detected by computed tomography.

Multiple atypical adenomatous hyperplasia (AAH) of both lungs in a 72-year-old male, detected by computed tomography, is reported. The lesions of the right lung were resected for diagnosis via video-assisted thoracoscopic surgery (VATS). The resected specimen had 22 AAH lesions up to 10 mm in size. For nine of these lesions, the expressions of carcinoembryonic antigen (CEA), c-erbB-2 oncoprotein and p53 gene product were examined by immunohistochemistry and the loss of heterozygosity (LOH) on chromosomes was investigated by polymerase chain reaction analysis. These lesions showed a variety of expressions for CEA, c-erbB-2 and p53 oncoprotein. Three of the nine lesions showed LOH on chromosome 13q, although this was not exhibited in the largest one. These results indicate that each AAH in this case has independent genetic abnormalities and is multicentric.

Pressure-controlled ventilation via a minitracheostomy tube: experimental study using a mechanical lung model.

To obtain basic data on pressure-controlled ventilation (PCV) via a minitracheostomy tube (MTT), we conducted an experimental study using a mechanical lung model. MTTs with internal diameters of 4.0, 4.5-, and 5.0 mm were used. To examine the effectiveness of PCV via an MTT for the lung with low compliance, the ventilated volumes were measured at compliances ranging from 10 to 50 ml/cmH2O. The alveolar pressures and ventilated volumes of the 4.0-, 4.5-, and 5.0-mm MTTs were about 40%, 50%, and 60% of the values for the 8.0-mm endotracheal tube in the absence of air leakage, respectively, and in the presence of air leakage they fell a further 20%. To obtain a ventilated volume of 500 ml, the inspiratory pressures needed were 40, 30, and 20 cmH2O for the 4.0-, 4.5-, and 5.0-mm MTTs, respectively. In the model of low lung compliance (10 ml/ cmH2O), the ventilated volumes decreased to 40% of those seen in the normal compliance model (50 ml/cmH2O) at each inspiratory pressure, due to greater air leakage. PCV via an MTT produced acceptable ventilated volumes in the lung model with air leakage. However, our results indicate that under conditions of low lung compliance, PCV via a

What is the advantage of a thoracoscopic lobectomy over a limited thoracotomy procedure for lung cancer surgery?

BACKGROUND: To clarify any advantages of video-assisted thoracoscopic surgery (VATS) over anterior limited thoracotomy (ALT) for lobectomy in lung cancer, we compared the two procedures in a retrospective analysis. METHODS: Sex- and age-matched (+/- 5 years) lung cancer patients in clinical stage I who underwent lobectomy by means of VATS (n = 33) or ALT (n = 33) were compared in terms of the number of resected lymph nodes, operating time, intraoperative blood loss, duration of postoperative chest tube drainage, and chest pain. Pain was evaluated using a visual analog scale and analgesic requirements. Vital capacity (VC), respiratory muscle strength, and results of a 6-minute walking (6 MW) test were also compared preoperatively and 1 and 2 weeks postoperatively. RESULTS: Compared with the ALT group, the VATS group experienced less pain between postoperative day (POD) 1 and POD 7 (p < 0.05 to 0.001) and had lower analgesic requirements up to POD 7 (p < 0.001). However, there were no significant differences in pain on POD 14. There were also no significant differences in intraoperative factors or in the postoperative impairment of VC, respiratory muscle strength, and 6 MW test results. CONCLUSIONS: Although VATS lobectomy reduces chest pain during the first week after surgery compared with ALT, this advantage is lost within 2 weeks. Both techniques result in similar impairments of pulmonary function, respiratory muscle strength and walking capacity. Therefore, if curative resection of lung cancer by VATS would be technically difficult for any reason, including the surgeon's skill and experience, a limited open thoracotomy would be preferable from the standpoints of safety and the patient's prognosis.

[Dumon stent placement via endotracheal tube].

We conducted a Dumon stent placement via endotracheal tube for 10 patients with airway stenosis. The conventional endotracheal tube is inserted beyond the stenosis site; this procedure is conducted with the use of a flexible bronchoscope under general anesthesia. The Dumon stent is folded and inserted into the endotracheal tube and is then introduced into the stenosis site with the use of a cylindrical-tipped stainless steel wire as a pusher. Although the Dumon stents were placed using a rigid bronchoscope for the first 7 patients, the present procedure was used for the latest 10 patients. Compared with the rigid bronchoscope technique, this procedure is suitable for the placement of a larger stent for a shorter time. It has the following advantages over the rigid bronchoscope technique: (1) the use of an endotracheal tube and flexible bronchoscope makes the stent placement easier for the practitioner and less stressful for the patient; (2) because of the flexibility of the endotracheal tube, a Dumon stent can be placed easily, even in the left main bronchus or in a markedly shifted trachea or bronchus, and also in a patient who has difficulty in expanding the neck; (3) a stent can be placed safely in a patient with severe tracheal stenosis and orthopnea. The present procedure does, however, have the disadvantage that it is difficult to control the direction of the tip of the endotracheal tube. We concluded that the present procedure could be a useful method for Dumon stent placement.

[A case of lung cancer with extensive pleural adhesion, which could be resected by a thoracoscopic middle lobectomy].

A thoracoscopic middle lobectomy was performed for a 78-year-old male with lung cancer associated with extensive pleural adhesion. After peeling off the area of pleural adhesion surrounding the surgical ports by finger, the thoracoscope was inserted into the thorax and then the area of adhesion in the other area was also peeled off under thoracoscope. A pulmonary vein was resected using a stapler. Due to adhesion at the fissures between the lobes, a pulmonary artery and bronchus of the middle lobe were cut from the front of the lung hilum. After that, the fissures between the lobes were also cut using a stapler thus resulting in a complete middle lobectomy. The operation time was 5 hours and 28 minutes, and the intraoperative bleeding was 200 ml. There was no postoperative air leakage, and the chest drain could be removed the day after surgery. In conclusion, even for lung cancer with extensive pleural adhesion, a thoracoscopic lobectomy can still be successfully performed. When a fissure between the lobes is found to adhere, the approach to pulmonary artery and bronchus from the front of the lung hilum is useful for performing a thoracoscopic middle lobectomy.

Early removal of chest drainage tubes and oxygen support after a lobectomy for lung cancer facilitates earlier recovery of the 6-minute walking distance.

The aim of this study was to assess the effects of the early removal of chest tubes and oxygen support lines on the postoperative recovery of patients, who underwent a lobectomy for lung cancer. Forty-two patients, in whom the removal of chest tubes and oxygen support lines was planned for the morning after surgery (subjective group), were matched by sex and age with 42 patients for whom no such action was scheduled (control group). The mean duration of chest tube drainage was 1.5 +/- 0.8 days in the subjective group, which was significantly shorter than the period of 2.8 +/- 1.0 days in the control group (P < 0.001). The mean duration of oxygen support was 1.1 +/- 0.3 days in the subjective group, which was significantly shorter than the period of 3.1 +/- 1.3 days in the control group (P < 0.001). There was no significant difference in the chest drainage volume and oxygen saturation on the morning after surgery between the two groups. We thus compared the postoperative changes in vital capacity (VC) and 6-min walking distance (6MWD) after surgery between the two groups. The early removal of chest tubes and oxygen support lines significantly reduced the impairments of 6MWD 1 week after surgery (P = 0.04) and also diminished the impairments of VC 1 week after surgery but not to a significant extent (P = 0.06). The early removal of chest tubes and oxygen support lines could accelerate the postoperative recovery of 6MWD.

Comparison of short-term versus long-term epidural analgesia after limited thoracotomy with special reference to pain score, pulmonary function, and respiratory muscle strength.

To determine the optimal duration of epidural analgesia (EA) after lung cancer surgery, a retrospective analysis was conducted to compare chest pain, pulmonary function, and respiratory muscle strength between patients given EA until postoperative day (POD) 3 and those given EA until POD 8. Each group comprised 25 lung cancer patients who underwent a lobectomy under anterior limited thoracotomy and given continuous thoracic EA using morphine until POD 3 (POD3-EA group) or POD 8 (POD8-EA group). The two groups were matched by sex and age. Postoperative pain from PODs 1 to 12 was evaluated by the pain score and analgesic requirements. The pulmonary function and respiratory muscle strength were measured on POD 7. The POD3-EA group did not experience any increase in pain after withdrawal, but the POD8-EA group did show a significant increase in pain the day after withdrawal (P < 0.05). The pain scores on PODs 8 and 9 in the POD8-EA group were significantly higher than those in the POD3-EA group (P < 0.05). There was no significant difference in pulmonary function and respiratory muscle strength on POD 7 between the two groups. Although the postoperative thoracic EA did not affect pulmonary function and respiratory muscle strength, prolonged thoracic EA after a limited thoracotomy significantly increased the pain after withdrawal, thus negatively affecting postoperative pain control.

Differentiating early malignant lung tumors from inflammatory nodules to minimize the use of video-assisted thoracoscopic surgery or open biopsy to establish a diagnosis.

To decrease the frequency of video-assisted thoracoscopic surgery (VATS) biopsy being used to diagnose inflammatory nodules, we studied the clinicopathological findings of lung cancers and inflammatory nodules diagnosed by VATS or open-lung biopsy. We studied 46 lung cancers and 47 inflammatory nodules smaller than 30mm in diameter diagnosed by VATS or open-lung biopsy. While the computed tomography (CT) findings were not significantly different between lung cancers and inflammatory nodules, N1 or N2 lung cancers more frequently showed distinct malignant features on CT than T1N0M0 lung cancers (P < 0.05). A review of previous chest X-ray films revealed that those of inflammatory nodules showed new nodules more frequently and nodular enlargement less frequently than those of lung cancer (P < 0.01). Of 13 lung cancers that showed nodular enlargement during a mean 15-month period, 12 were T1N0M0. Nondiagnosable small lung nodules, which had few malignant features on CT and had newly appeared on a chest X-ray film, were more likely to be inflammatory nodules than lung cancers; and even if they were lung cancers, the tumor stage was usually T1N0M0. Thus, to decrease the incidence of VATS biopsy being performed for inflammatory nodules, intensive follow-up by CT until slight nodular enlargement becomes evident could be a means of revealing nondiagnosable small lung nodules without distinct malignant findings, except for nodules found to be enlarging on a review of retrospective films.

Intrathoracic transposition of a pectoralis major and pectoralis minor muscle flap for empyema in patients previously subjected to posterolateral thoracotomy.

The latissimus dorsi muscle flap cannot be used to eliminate an empyema cavity in patients who have previously undergone posterolateral thoracotomy, because of the division of this muscle. Moreover, thoracoplasty alone cannot sufficiently eliminate an empyema cavity that includes the thoracic apex, where space remains between the clavicle and the first rib. Therefore, we constructed a flap from the pectoralis major (P.Ma) and pectoralis minor (P.Mi) muscles to eliminate empyema cavities in five patients who had undergone lobectomy (n = 3) or pneumonectomy (n = 2) via posterolateral thoracotomy from 3 months to 40 years previously. All five patients had bronchopleural fistulae, and because of the previous upper lobectomy or pneumonectomy, they had large empyema cavities including the thoracic apex. Open-drainage thoracotomy was performed due to severe infection, and intrathoracic transposition of the P.Ma and P.Mi muscle flap with simultaneous thoracoplasty was carried out 7-124 weeks (mean 38 weeks) later. The P.Ma and P.Mi muscle flap easily reached the apex space with sufficient obliteration of the empyema cavity. All of the patients remained free of empyema 12-85 months after thoracic closure. The P.Ma and P.Mi muscle flap is useful for eliminating empyema cavities including the thoracic apex in patients who have previously undergone a posterolateral thoracotomy.

[A case of post-thymomectomy myasthenia gravis after extrapleural pneumonectomy for invasive thymoma which necessistated long-term mechanical ventilation].

The patient was a 58-year-old male with invasive thymoma which had disseminated in the left thorax and was histologically a polygonal cell type lesion. While the serum value of anti-acetylcholine receptor antibody was high before surgery, there were signs of myasthenia gravis. After preoperative chemotherapy, a thymectomy and left panpleuropneumonectomy were conducted. Forty days after surgery, the patients suffered post-thymomectomy myasthenia gravis, which necessitated mechanical ventilation for 6 months. Despite steroid therapy and 17 plasmapheresis procedures the tidal volume increased by little more than 200-250 ml during that time. The causes of ventilatory failure, therefore, were probably decreased pulmonary function due to extrapleural pneumonectomy and the myasthenia gravis. According to the literature, polygonal cell type thymomas with high serum levels of anti-acethycholine receptor antibody have higher incidences of post-thymomectomy myasthenia gragvis than other ones. Therefore, the risk of post-thymomectomy myasthenia gravis should be kept in mind when extrapleural pneumonectomy for invasive thymoma is being considered, especially in the cases of this type.

[Low body mass index and exercise capacity in patients with chronic obstructive pulmonary disease (COPD)].

This study examined retrospectively the relationships between body weight and exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Seventeen patients with a %FEV1 less than 55% (mean +/- SD 36% +/- 8.8%) and minimum body weights of the body mass index (BMI) less than 20 (17.3 +/- 1.7) performed incremental exercise testing using a treadmill. Seventeen %FEV1-matched control patients with normal body weights were selected. There were no significant differences in the patients' characteristics or their pulmonary function tests (including vital capacity, carbon monoxide diffusing capacity, and arterial blood gases). Low BMI patients Is this the weaning of (67.8 +/- 6.3 years old) were younger than the control patients (73.1 +/- 8.5 years old), but the difference was not statistically significant. The exercise capacities of low BMI patients were significantly superior to those of the control patients (316.5 +/- 171.5 seconds vs 204.1 +/- 116.3 seconds, p = 0.038) and total walking distance without statistical significance (194.9 +/- 117.0 m vs 125.7 +/- 98.0 m, p = 0.071). Also, low BMI patients achieved higher maximal minute ventilation volume during exercise than the controls. The major factor limiting exercise in patients with low BMI was ventilation. Moderately low body weight may not be a risk factor in Japanese COPD patients.

Mixing collagen with fibrin glue to strengthen the sealing effect for pulmonary air leakage.

BACKGROUND: To strengthen the sealing effect of fibrin glue for pulmonary air leakage, atelocollagen was mixed with the glue and the mixing effect was examined. METHODS: A mixture of fibrinogen and thrombin with atelocollagen was used as a test sample. The concentrations of atelocollagen were adjusted to levels of 0%, 0.375%, 0.75%, 1.1%, and 1.5%. We next performed air leakage tests on a plastic cap with pin holes and swine lung and also measured the elasticity and the adhesion strength. RESULTS: The pressure required to rupture the sealant on a plastic cap with pin holes increased as the concentration of atelocollagen increased, and the bursting pressures were significantly higher in the glue with 0.75%, 1.1%, and 1.5% of atelocollagen than in the glue without atelocollagen (p < 0.01 and p < 0.001). The air leakage pressure on the swine lung was significantly higher in the glue with 0.375%, 0.75%, and 1.1% of atelocollagen than in the glue without atelocollagen (p < 0.05 and p < 0.01), and it was the highest with 0.75%. The elasticity of the glue significantly increased as the concentration of atelocollagen increased (p < 0.001). However, the adhesion strength of the glue significantly decreased as the concentration of atelocollagen increased (p < 0.05 to p < 0.001). CONCLUSIONS: The mixing of atelocollagen with fibrin glue more effectively sealed pulmonary air leakage due to an increased elasticity of the glue while its adhesion strength decreased. The optimal concentration of atelocollagen in the fibrin glue to obtain the best sealing effect was 0.75%.

Pressure-controlled ventilation via a mini-tracheostomy tube for patients with neuromuscular disease.

The authors managed 10 patients with Duchenne muscular dystrophy (DMD) and five with MG with pressure-controlled ventilation (PCV) via mini-tracheostomy tube (MTT). The arterial partial pressure of CO2 (PaCO2) of the patients with DMD decreased after conversion to PCV via MTT from biphasic positive airway pressure (BIPAP) or a body ventilator. The MG patients could be converted from conventional volume-controlled ventilation to PCV via MTT. PCV via MTT achieves more effective ventilation than either BIPAP or a body ventilator and is as effective as ventilation via a conventional tracheal tube.