Use of a pericardial fat pad flap for preventing bronchopleural fistula: an experimental study focusing on the angiogenesis and cytokine production of the fat pad

Novel method for bronchial stump coverage for prevents postpneumonectomy bronchopleural fistula: pedicled thymopericardial fat flap

Background

Bronchopleural fistula (BPF) is a serious complication with high mortality and morbidity that can be seen after lung resections. Although several methods have been described to prevent postoperative BPF it is still unclear which method is the best. In this study, we have used tymopericardial fat flap (TPFF) to cover the bronchial stump in patients after pneumonectomy and aim to show its feasibility and efficacy to prevent BPF.

Methods

Between January 2013 and June 2021, 187 patients with lung cancer underwent pneumonectomy at our institution. Among them, 53 patients underwent bronchial stump coverage with TPFF. In other 134 patients there wasn’t used any coverage method. Patient characteristics, preoperative status, surgical procedures, perioperative course, pathological findings, and long-term prognoses were evaluated retrospectively.

Results

Postoperative BPF was observed in 16 (%8.5) patients. It was observed that TPFF was applied in only 1 of the patients who developed BPF. A statistically significant difference was detected between TPFF-coverage with non-coverage groups in terms of postoperative BPF rates (p = 0.044). Other factors associated with the development of postoperative BPF in univariate analysis were right sided pneumonectomy, and re-operation.

Conclusion

Bronchial stump coverage with TPFF is a feasible and effective method to prevent postpneumonectomy BPF.

Autologous Multilayered Fibroblast Sheets Can Reinforce Bronchial Stump in a Rat Model

Bronchopleural fistula is one of the most serious postoperative complications caused by the incomplete healing of a bronchial stump. Fibroblasts play an important role in wound healing by facilitating connective tissue formation and inducing angiogenesis. We developed a method for production of multilayered fibroblast sheets that secreted some growth factors and promoted wound healing. The present study aimed to assess the treatment effect of multilayered fibroblast sheets on bronchial stump healing. In this rat model, left pneumonectomy was performed, and multilayered fibroblast sheets derived from autologous oral mucosal tissues were transplanted to the bronchial stump. The changes in the bronchial stump were examined macroscopically, histologically, and mechanically. The fibroblast sheets promoted the formation of thick connective tissues around the bronchial stump. The formed connective tissues were accompanied by new blood vessels, and fibrosis was observed over time. Then, 7 days after the transplantation of the fibroblast sheets, the bronchial wall became significantly thicker, and the area of the blood vessels for the bronchial wall tissues was significantly larger in the experimental group than in the control group. In addition, the burst pressure in the bronchial stump was significantly higher in the experimental group than in the control group. Bronchial stumps were reinforced by the transplantation of multilayered fibroblast sheets derived from autologous oral mucosal tissues.

Pericardial fat pad plombage for pulmonary cavity causing massive air leakage

Background

Secondary pneumothorax after chemotherapy for a malignant pulmonary tumor is a complication from a large cavity causing refractory pneumothorax.

Case presentation

A 61-year-old man was referred due to prolonged air leakage from a pulmonary cavity that developed after treatment for pulmonary metastases from renal cell carcinoma. As air leakage continued after thoracic drainage and endobronchial occlusion, we planned thoracoscopy-assisted surgery. Intraoperatively, a large cavity opening to the pulmonary cavity was found in the left upper lobe. As it was difficult to repair the fistula using staplers or direct sutures because the pleura around the cavity was thick and hard, we attempted to plombage the cavity with a pericardial fat pad. After the operation, air leakage immediately disappeared and no recurrence of the pneumothorax was found.

Conclusion

This novel method can be useful to seal a large bronchopleural fistula that causes refractory pneumothorax.

[Clinical Effect of Pedicled Pericardial Fat Flap in Prevention of Bronchial Pleural Fistula in Bronchial Sleeve Lobectomy]

背景与目的

支气管袖式肺叶切除是中心型肺癌重要的手术方式，它是最能体现“最大程度切除肿瘤，同时最大程度保留肺功能”的肺癌手术原则。支气管胸膜瘘是支气管袖式肺叶切除最严重的手术并发症，严重威胁患者的生命安全。本文将总结带蒂心包脂肪垫包裹支气管吻合口在预防支气管袖式肺叶切除术后支气管吻合口瘘的临床效果。

方法

回顾性分析四川大学华西医院肺癌中心2016年1月-2019年5月期间行支气管袖式肺叶切除术，并用带蒂心包脂肪垫包裹支气管吻合口的39例中心型肺癌患者临床资料，观察该组患者术后并发症，尤其是支气管吻合口相关并发症发生情况。

结果

该组患者手术后恢复良好，均于术后6 d-14 d内出院；30 d内无支气管胸膜瘘发生，无因胸腔内出血再次行手术病例，无严重心律失常，无严重肺部感染及呼吸衰竭发生；术后继续随访期间，术后6个月发生重度吻合口狭窄导致术侧残余肺不张1例。

结论

支气管袖式肺叶切除的肺癌患者，术中用带蒂心包脂肪垫包裹支气管吻合口，可有效预防术后吻合口瘘相关并发症的发生，从而提高手术安全性。

Postoperative changes of the free pericardial fat pad for bronchial stump coverage

Background

Bronchopleural fistula (BPF) remains a serious complication after surgery for lung cancer with bronchial resection. A free pericardial fat pad (FPFP) is applied in high-risk cases to reduce BPF frequency. BPF may occur 6 months after surgery. Thus, we evaluated the residual FPFP volume at 6 months after surgery to estimate the residual FPFP ratio and determine the amount of FPFP to be harvested during surgery.

Methods

We retrospectively investigated 40 patients who underwent lobectomy with bronchial stump coverage using FPFP. During surgery, the volume of the harvested FPFP was measured and the FPFP was affixed to the bronchial stump. Further, 6 months after surgery, the residual volume of the installed FPFP was analyzed using a three-dimensional volume analyzer and the residual ratio was calculated. We also evaluated clinicopathological factors influencing the resected FPFP and residual ratio.

Results

The median resected FPFP volume was 11 [3-40] mL. During multivariate analysis, body mass index and surgical approach were found to be significant factors associated with the resected FPFP volume. The median residual FPFP volume was 4.3 (0.4-15.5) mL. The median residual ratio was 0.39 (0.13-0.66). The resected FPFP volume was significantly associated with the residual volume (P<0.001) but not with the residual ratio (P=0.811). No factor was associated with the residual ratio.

Conclusions

In all cases, residual FPFP was confirmed at 6 months after surgery and the residual ratio was 40%. It is necessary to determine the volume of FPFP to be harvested while carefully considering the shrinkage ratio.

Bronchial Stump Coverage and Postpneumonectomy Bronchopleural Fistula

To prevent postpneumonectomy bronchopleural fistula, coverage of the bronchial stump is recommended, especially for patients treated with neoadjuvant and adjuvant chemotherapy or radiochemotherapy. We compared outcomes after proximal pericardial fat pad coverage and coverage with pleura and surrounding tissues, by retrospective analysis of the records of 243 patients. Postpneumonectomy bronchopleural fistula occurred in 7/143 (4.9%) patients who had pericardial fat pad coverage, and in 6/100 (6.0%) treated by pleural covering. Bronchopleural fistula occurred in 11 patients within 21 days, in one after 2 months, and one after 6 months. Univariate analysis of comorbidities and risk factors did not show any significant differences between the groups. Advanced T stage and carcinomatous lymphangiosis at the resection margin were associated with a higher risk of bronchopleural fistula development, independent of the technique. Reinforcement of the bronchial stump by proximal pericardial fat pad coverage appears to be safe and feasible. It is comparable to coverage with pleura and surrounding tissues.

Angiogenesis in adipose tissue

Angiogenesis is required for the growth and expansion of both healthy and pathological tissues. The plasticity of the adipose tissue is reflected by its remarkable ability to expand or to reduce in size throughout the adult lifespan. We, and others, have recently shown that expansion of fat mass is dependent on angiogenesis, and suppression of angiogenesis might provide a novel therapeutic approach for prevention and treatment of obesity. Here, we outline two technical procedures for assessment of angiogenesis in adipose tissues.

Revascularization of trachea in lung and tracheal transplantation

Ischemia is the primary risk factor for airway complications in double lung transplantation using tracheal anastomosis and in tracheal transplantation. Many treatment options as to revascularization for the trachea were herein described and reviewed. They include direct revascularization (using a conduit such as artery or vein), revascularization with tissue wrapping (using omentum, muscle, internal thoracic artery pedicle, pleura, or pericardial fat pad), and with drug administration (using corticosteroid hormone, prostaglandin, or angiogenic factor). As there are few organized reports including new information on revascularization for the trachea these days, this review article would help thoracic surgeons who get engaged transplantation.

Experimental repair of phrenic nerve using a polyglycolic acid and collagen tube

OBJECTIVE

The feasibility of a nerve guide tube for regeneration of the phrenic nerve with the aim of restoring diaphragmatic function was evaluated in a canine model.

METHODS

The nerve tube, made of woven polyglycolic acid mesh, had a diameter of 3 mm and was filled with collagen sponge. This polyglycolic acid-collagen tube was implanted into a 10-mm gap created by transection of the right phrenic nerve in 9 beagle dogs. The tubes were implanted without a tissue covering in 5 of the 9 dogs (group I), and the tubes were covered with a pedicled pericardial fat pad in 4 dogs (group II). Chest x-ray films, muscle action potentials, and histologic samples were examined 4 to 12 months after implantation.

RESULTS

All of the dogs survived without any complications. x-ray film examination showed that the right diaphragm was paralyzed and elevated in all dogs until 3 months after implantation. At 4 months, movement of the diaphragm in the implanted side was observed during spontaneous breathing in 1 dog of group I and in 3 dogs of group II. In the dogs showing diaphragm movement, muscle action potentials were evoked in the diaphragm muscle, indicating restoration of nerve function. Regeneration of the phrenic nerve structure was also examined on the reconstructed site using electron microscopy.

CONCLUSION

The polyglycolic acid-collagen tube induced functional recovery of the injured phrenic nerve and was aided by coverage with a pedicled pericardial fat pad.

Adipose graft: an original option in myringoplasty

OBJECTIVE

To describe the fat graft as a reconstructive material in myringoplasty.

METHOD

In a review of 45 patients conducted between 1993 and 1999, the authors analyzed their patients' outcomes after having myringoplasties with fat graft. Median follow-up was 2.5 years (range, 6 mo-6 yr).

RESULTS

We achieved a success rate of 91.1%. Different features of the patient and the tympanic perforation were studied to demonstrate their role in the quality of the surgical closing. A review of the literature was done to compare our results with the results of other series using this type of graft as well as with studies of the temporalis fascia as a graft material.

CONCLUSION

The high reliability of the fat graft and the technical simplicity of this procedure in anterior perforations, especially with the use of intraoperative endoscopy, make it an attractive technique.

Preservation of a digital osteotendinous structure with an omental flap

Taking into account the angiogenic properties of the omentum to revascularize ischemic tissues, this experimental, longitudinal, prospective, double-blind study in rabbits was designed to revascularize and preserve the mobility of a digital osteotendinous structure surgically devascularized in advance and to compare such omental angiogenic ability with that of the muscle and the panniculus carnosus. Thirty New Zealand rabbits were used. Three toes from the hind feet were surgically amputated from each rabbit. The skin was removed, exposing the bones, tendons, ligaments, and joints, to form what we termed the osteotendinous structure. Through a median laparotomy, the first part of each rabbit's own osteotendinous structure was placed inside the panniculus carnosus (group I), the second under the rectus abdominis muscle (group II), and the third was wrapped in a pediculate omental flap (group III). Three weeks later, each structure was assessed clinically for mobility and fibrosis and microscopically for fibrosis, newly formed vessels, viability, and tissue regeneration. Clinically, the group I structures showed a greater amount of fibrosis. The structures in groups II and III showed minimal fibrosis in all but four cases, which showed moderate fibrosis. Differences in joint mobility were assessed with the Kruskal-Wallis test. There was a statistically significant difference in mobility for the structures from group III, which was higher, followed by those from groups II and I. The exception was the proximal interphalangeal joints in groups II and III, for which the differences had no statistical significance. Microscopically, fibrosis and tissue necrosis were intense in the structures in group I, moderate in the group II structures, and mild in the group III structures. Conversely, vessel neoformation and tissue regeneration were intense in the structures in group III, moderate in group II, and were nil in group I. This study confirms with statistical significance that, in the rabbit, the omentum has a higher ability to revascularize degloved tissues than do the muscle and the panniculus carnosus, thus preserving a higher joint and tendon mobility. Consequently, it is suggested that a free omental flap be used in the treatment of ring avulsion injuries that lead to degloving of the digits.