Adhesion barriers in cardiac surgery: A systematic review of efficacy

Microvascular Decompression Using the Gelatin Sponge Insertion Technique for Trigeminal Neuralgia: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

Microvascular decompression (MVD) is the primary surgical intervention for trigeminal neuralgia (TN), with Teflon being the most conventional decompressing material. However, Teflon has been associated with adhesion and granulomas after MVD, which closely correlated with the recurrence of TN. Therefore, we developed a new technique to prevent direct contact between Teflon and nerve. The purpose of this study is to compare the efficacy of MVD using the gelatin sponge (GS) insertion technique with that of Teflon inserted alone in treating primary TN.

METHODS

We retrospectively analyzed the medical records and the follow-up data of 734 patients with unilateral primary TN who underwent MVD at our center from January 2014 to December 2019. After exclusions, we identified 313 cases of GS-inserted MVD and 347 cases of traditional MVD. The follow-up exceeded 3 years.

RESULTS

The operating time of the GS-inserted group was longer than that of the Teflon group (109.38 ± 14.77 vs 103.53 ± 16.02 minutes, P < .001). There was no difference between 2 groups in immediate surgical outcomes and postoperative complications. The yearly recurrence rate for GS-inserted MVD was lower at first (1.0%), second (1.2%), and third (1.2%) years after surgery, compared with its counterpart of Teflon group (3.7%, 2.9%, and 1.7% respectively). The first-year recurrence rate ( P = .031) and total recurrence rate in 3 years ( P = .013) was significantly lower in the GS-inserted group than Teflon group. Kaplan-Meier survival analysis demonstrated better outcomes in GS-inserted MVD groups ( P = .020).

CONCLUSION

The application of the GS insertion technique in MVD reduced first-year postoperative recurrence of TN, with similar complications rates compared with traditional MVD.

Enhanced Biodegradation of Silk Fibroin Hydrogel for Preventing Postoperative Adhesion

An absorbable adhesion barrier is a medical device that prevents postoperative adhesion and matches its biodegradation time with the regeneration period of its target tissues, which is important for antiadhesion effects. Physical hydrogels of Bombyx mori silk fibroin (SF) proteins are degradable in vivo. However, their biodegradation time is too long to exert antiadhesion effects. To shorten the biodegradation time of the SF hydrogels, we decreased the molecular weight (MW) of the SF proteins by alkaline treatment and prepared low-MW (LMW) SF hydrogels. The hydrogels contained less β-sheet crystalline and more amorphous structures than conventional, high-MW (HMW) SF hydrogels. Because of the potential loosened SF molecular structures in the hydrogel networks, the LMW SF hydrogels showed enhanced biodegradation (i.e., shorter in vitro enzymatic biodegradation time and faster in vivo biodegradation rate) as well as a lower affinity for plasma proteins and fibroblasts, which are involved in postoperative adhesion formation. An antiadhesion test using a rat abdominal adhesion model demonstrated that the LMW SF hydrogel applied to the abraded cecum was almost completely degraded within two weeks postimplantation, with a significantly lower adhesion severity score than that in the untreated model rat group. Conversely, the HMW SF hydrogel remained between the cecum and abdominal wall, with the same adhesion severity as that of the untreated model rat group. Therefore, we concluded that the antiadhesion effects of SF hydrogels were induced by enhanced biodegradation. The results of this study indicate the potential of LMW SF hydrogels as absorbable adhesion barriers.

Pulmonary artery sarcoma and severe valvular diseases in late-septuagenarian women: was 2-stage surgery an appropriate strategy? A case report

BACKGROUND

Pulmonary artery sarcomas (PASs) are rare, and complete tumor resection is often difficult at the time of detection. We encountered a case of PAS that was thought to be resectable; however, the patient had severe symptomatic valvular disease. We faced a difficult decision regarding the surgical strategy.

CASE PRESENTATION

A 76-year-old female presented with a history of polysurgery for multiple primary cancers. She was referred to our department with a calcified mass in the right pulmonary artery (PA) and severe symptomatic valvular disease. After a discussion with the cardiovascular surgeon, we decided to perform a two-stage surgery. She underwent valvuloplasty through a median sternotomy, resulting in an improvement in her exertional dyspnea. The tumor was removed three months later with a right upper lobectomy and PA patch reconstruction through a posterolateral thoracotomy. When the PA was opened, the edge of the tumor was entrapped by vascular clamp forceps because of insufficient dissection of the adhesions between the superior vena cava and the right main PA resulting from the first operation. The patient underwent proton therapy twice for chest wall metastases which recurred three months after surgery, and local recurrence in the PA was diagnosed five months after surgery. The patient was alive with stable disease 25 months after surgery.

CONCLUSION

Two-stage surgery for PAS and valvular disease resulted in incomplete resection of the PAS in the right PA. It is important not to underestimate surgical adhesions due to the initial surgery and to consider and implement measures to prevent adhesions of critical vessels during the second operation.

Delayed coronary artery stenosis: a rare complication of the left atrial clipping device

A clipping device may impinge on the coronary artery following left atrial appendage occlusion during cardiac surgery, causing rare cardiac ischaemia perioperatively. This report highlights a case of delayed severe coronary artery stenosis resulting in ventricular fibrillation 2 months after cardiac surgery with the implantation of a left atrial clipping device. Following a percutaneous coronary intervention, the patient underwent clip removal surgery. Postoperative three-dimensional heart model verification revealed that the base of the left atrial appendage was more dorsal than usual, thereby increasing the potential risk of the clip impinging on the coronary artery. We should remember that this rare complication can occur after left atrial clipping, either in the early postoperative period or later.

A review of animal models for post-operative pericardial adhesions

Post-operative pericardial adhesions remain a serious complication after cardiac surgery that can lead to increased morbidity and mortality. Fibrous adhesions can destroy tissue planes leading to injury of surrounding vasculature, lengthening of operation time, and increased healthcare costs. While animal models are necessary for studying the formation and prevention of post-operative pericardial adhesions, a standardized animal model for inducing post-operative pericardial adhesions has not yet been established. In order to address this barrier to progress, an analysis of the literature on animal models for post-operative pericardial adhesions was performed. The animal model, method used to induce adhesions, and the time to allow development of adhesions were analyzed. Our analysis found that introduction of autologous blood into the pericardial cavity in addition to physical abrasion of the epicardium caused more severe adhesion formation in comparison to abrasion alone or abrasion with desiccation (vs. abrasion alone p = 0.0002; vs. abrasion and desiccation p = 0.0184). The most common time frame allowed for adhesion formation was 2 weeks, with the shortest time being 10 days and the longest being 12 months. Finally, we found that the difference in adhesion severity in all animal species was similar, suggesting the major determinants for the choice of model are animal size, animal cost, and the availability of research tools in the particular model. This survey of the literature provides a rational guide for researchers to select the appropriate adhesion induction modality, animal model, and time allowed for the development of adhesions.