Jianyong Ding

Histological examination of cryopreserved rat tracheal grafts.

It has been reported that tracheal tissue treated by cryopreservation can be used for tracheal replacement in the absence of immunosuppressants. However, the mechanism of reduced antigenicity is unclear. We investigated this issue in cryopreserved rat trachea using detailed histologic evaluation. Rat tracheal segments were preserved in a cryopreservative solution at −85°C. The epithelium of tracheal segments (n = 6 in each group) was subjected to light microscopic and scanning electron microscopic examination before freezing and after cryopreservation for 1 week, 1 month, 3 months, and 6 months. The expression of major histocompatibility complex II (MHC-II) was determined using frozen sections. Ultrastructure of dendritic cells (DCs) was observed by transmission electron microscopy. Tracheal epithelium was partially intact even after 6 months in cryopreservation, although cellularity decreased with time. MHC-II antigen expression was detected even at 6 months, although expression was lower than that measured on fresh tissue. Tracheal tissue DCs displayed dilatations of perinuclear cisterna and degeneration of vacuoles. Density of the mitochondrial matrix was increased. These results suggest that damage to the epithelium and DCs during cryopreservation and concomitant loss of MHC-II expression might explain the reduction of antigenicity.

Risk factors of myasthenic crisis after thymectomy for thymoma patients with myasthenia gravis

OBJECTIVES Total thymectomy should be performed on thymoma patients with myasthenia gravis. The aim of the present study was to investigate the risk factors of postoperative myasthenic crisis (POMC) occurrence in these patients. METHODS The clinical records of 127 thymoma patients with myasthenia gravis (68 men, 59 women; median age, 50 years) who underwent total thymectomy at our institution from 2005 to 2014 were retrospectively reviewed. The following factors were analysed in relation to POMC: gender, age, duration of symptoms, bulbar symptoms, smoking history, history of myasthenic crisis, comorbidities, perioperative pyridostigmine and prednisolone therapy, spirometric and blood gas parameters, Osserman stage, operation approach, major complications, World Health Organization (WHO) histologic classification, Masaoka stage and use of immunoglobulins or plasmapheresis. RESULTS Thirteen patients (10%) experienced POMC and required intubation. All patients were weaned after 2‐28 days (median 9 days) and were discharged. Univariate analysis revealed a correlation between POMC and Osserman‐stage IIA‐IV [odds ratio (OR) = 4.928, 95% confidence interval (CI) = 1.286‐18.882, P = 0.01], bulbar symptoms (OR = 3.828, 95% CI = 1.112‐13.176, P = 0.04), and forced expiratory volume in one second <70% pred forced expiratory volume in one second (OR = 4.856, 95% CI = 1.380‐17.081, P = 0.02). In addition, more frequent POMC occurred in WHO type B2‐B3 than in type A‐B1 thymomas (OR = 8.118, 95% CI = 1.020‐64.590, P = 0.03). Multivariate logistic regression analysis showed that WHO histologic classification B2‐B3 (OR = 10.041, 95% CI = 1.228‐82.090, P = 0.03) and Osserman‐stage IIA‐IV (OR = 5.953, 95% CI = 1.506‐23.538, P = 0.01) independently predicted POMC. CONCLUSIONS Osserman stage (IIA‐IV) and WHO type B2‐B3 thymomas are independent predictors of POMC in thymoma patients with myasthenia gravis who have undergone total thymectomy. Thus, adequate perioperative care should be provided to these patients.

Ultrastructural changes in cryopreserved tracheal grafts of sprague-dawley rats.

It has been reported that immunosuppressant-free tracheal transplantation can be achieved by using cryopreserved grafts. However, the ultrastructural changes of cryopreserved tracheal tissue remain unclear. This study investigated this issue in cryopreserved tracheal grafts of 30 Sprague-Dawley (SD) rats, divided into five groups (n = 6 rats/group). Tracheal rings removed from them were stored in a deep freezer at −85°C for 1 week, 1 month, 3 months, or 6 months. Never frozen tracheal tissues were obtained from the control group. Ultrastructural changes in the cryopreserved tracheas of each group were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). As the duration of cryopreservation lengthened, tracheal grafts were observed by SEM to develop an obviously speckled depletion of epithelium, accompanied by a loss of cilia in the remaining epithelium. TEM examination of chondrocytes that had been cryopreserved for 3 months revealed obvious injury. Cell membranes and nuclei were frequently observed to be ruptured, and fibrils appeared disorganized and randomly oriented. As the time of cryopreservation increased, ultrastructural injury to tracheal chondrocytes became more severe. The data indicated that the optimal maximum time for cryopreservation of tracheal grafts of SD rats might be <3 months with our methods.

Subxiphoid approach with sternum retractor for mediastinal tumor cephalad to brachiocephalic vein

The subxiphoid approach for mediastinal tumors involves resecting the tumor via incisions made below the xiphoid process (1). Because the camera is inserted through the midline subxiphoid region, the operative view of the neck region and locations of the bilateral intercostal nerves are easily accessible, especially with the help of a sternum retractor. Here, we introduce a case of mediastinal tumor cephalad to the brachiocephalic vein resected via the subxiphoid approach.

A novel hybrid technique for localization of subcentimeter lung nodules

BACKGROUND It is technically challenging to locate non-visible, non-palpable subcentimeter ground-glass nodules (GGNs) of lung during video-assisted thoracic surgery (VATS). Computed tomography (CT)-guided marking of small pulmonary nodules using microcoils has been reported to be a practical method of preoperative localization, whereas dislodgement of microcoils remains to be a bothersome complication. The objective of this study was to assess the viability and effectiveness of a newly developed hybrid technique, which combines induced controllable pneumothorax and CT-guided microcoil marking procedure to reduce the risk of microcoil dislodgement. METHODS After induced minor pneumothorax, 35 patients with subcentimeter GGNs underwent CT-guided marking with microcoils prior to VATS sublobar resection or lobectomy. Histopathological analysis was performed after surgeries. RESULTS All of 37 nodules were successfully marked before VATS. Segmentectomy was performed in 8 cases, wedge resection in 19 cases and lobectomy in 8 cases. All nodules were completely removed with marking microcoils. Dislodgement of microcoils was not observed in all cases and mild pulmonary hemorrhage occurred in one case. No other complications occurred. CONCLUSIONS The newly developed hybrid technique which combines induced controllable pneumothorax and CT-guided marking using microcoils was feasible and reliable for VATS resection of subcentimeter GGNs, meanwhile significantly lowered the risk of microcoil dislocation.

Surgical Approaches to Non-thyrogenic and Non-thymic Mediastinal Tumors of the Thoracic Inlet

Abstract Background Non‐thyrogenic and non‐thymic mediastinal tumors of the thoracic inlet are in close proximity to several important vessels and nerves. The narrow confines of the thoracic inlet make complete excision of these tumors difficult, and selecting the appropriate surgical approach is important to successful resection. Methods Records from 57 patients who presented to our department with non‐thyrogenic and non‐thymogenic tumors of the thoracic inlet from November 2004 to November 2015 were reviewed. All but one of the patients received surgical treatment. Thirty‐two tumors were excised via video‐assisted thoracic surgery (VATS). Other approaches included thoracotomy, supraclavicular incision, supraclavicular incision plus thoracotomy/VATS, and a posterior midline approach with semi‐laminectomy combined with VATS. Results Tumors were resected completely in 54 cases and partially in one. One procedure (VATS) was aborted. There were no surgical mortalities, but there were some postoperative complications. The majority of the tumors were benign neurogenic tumors. Conclusions Most tumors of the thoracic inlet are benign and can be removed via VATS. Thoracotomy is the appropriate approach for large tumors, particularly in cases where the first to second rib cannot be visualized. A supraclavicular approach is recommended for resection of tumors arising from the brachial plexus, and a supraclavicular approach combined with VATS or thoracotomy may be useful for larger masses. A posterior midline approach with semi‐laminectomy combined with VATS is appropriate for dumbbell‐shaped tumors.

P25. VATS combined with a subxiphoid incision: a novel approach for large thymoma

In patients with thymoma larger than 5 cm in diameter, video-assisted thoracoscopic surgery (VATS) remains controversial as an approach for total thymectomy. Aside from the concerns such as possible rupture of tumor capsule, reduced safety margins and increased risk of local recurrence, how to remove specimen of this size from incisions of VATS is another problem that surgeons have to confront. We reported a case of a 47-year-old man who was referred to our department with a huge mass located on the anterior mediastinal and right hemithorax. After careful preoperative evaluation and planning, the tumor was completely removed by VATS and taken out of thoracic cavity through a subxiphoid incision. After resection, histologic analysis confirmed the diagnosis of thymoma B1 type. Postoperative course was uneventful and no adjuvant therapy was offered. The patient has continued to do well with no signs of recurrence at a follow-up of 10 months. We stress that VATS combined with a subxiphoid incision may be a useful surgical option for patients with thymoma larger than 5 cm in size.