Sternal closure after median sternotomy: a new technique using titanium hooks and wires applied parasternally

Advances, challenges, and prospects for surgical suture materials

As one of the long-established and necessary medical devices, surgical sutures play an essentially important role in the closing and healing of damaged tissues and organs postoperatively. The recent advances in multiple disciplines, like materials science, engineering technology, and biomedicine, have facilitated the generation of various innovative surgical sutures with humanization and multi-functionalization. For instance, the application of numerous absorbable materials is assuredly a marvelous progression in terms of surgical sutures. Moreover, some fantastic results from recent laboratory research cannot be ignored either, ranging from the fiber generation to the suture structure, as well as the suture modification, functionalization, and even intellectualization. In this review, the suture materials, including natural or synthetic polymers, absorbable or non-absorbable polymers, and metal materials, were first introduced, and then their advantages and disadvantages were summarized. Then we introduced and discussed various fiber fabrication strategies for the production of surgical sutures. Noticeably, advanced nanofiber generation strategies were highlighted. This review further summarized a wide and diverse variety of suture structures and further discussed their different features. After that, we covered the advanced design and development of surgical sutures with multiple functionalizations, which mainly included surface coating technologies and direct drug-loading technologies. Meanwhile, the review highlighted some smart and intelligent sutures that can monitor the wound status in a real-time manner and provide on-demand therapies accordingly. Furthermore, some representative commercial sutures were also introduced and summarized. At the end of this review, we discussed the challenges and future prospects in the field of surgical sutures in depth. This review aims to provide a meaningful reference and guidance for the future design and fabrication of innovative surgical sutures. STATEMENT OF SIGNIFICANCE: This review article introduces the recent advances of surgical sutures, including material selection, fiber morphology, suture structure and construction, as well as suture modification, functionalization, and even intellectualization. Importantly, some innovative strategies for the construction of multifunctional sutures with predetermined biological properties are highlighted. Moreover, some important commercial suture products are systematically summarized and compared. This review also discusses the challenges and future prospects of advanced sutures in a deep manner. In all, this review is expected to arouse great interest from a broad group of readers in the fields of multifunctional biomaterials and regenerative medicine.

Zinc-nutrient element based alloys for absorbable wound closure devices fabrication: Current status, challenges, and future prospects

The need for the development of load-bearing, absorbable wound closure devices is driving the research for novel materials that possess both good biodegradability and superior mechanical characteristics. Biodegradable metals (BMs), namely: magnesium (Mg), zinc (Zn) and iron (Fe), which are currently being investigated for absorbable vascular stent and orthopaedic implant applications, are slowly gaining research interest for the fabrication of wound closure devices. The current review presents an overview of the traditional and novel BM-based intracutaneous and transcutaneous wound closure devices, and identifies Zn as a promising substitute for the traditional materials used in the fabrication of absorbable load-bearing sutures, internal staples, and subcuticular staples. In order to further strengthen Zn to be used in highly stressed situations, nutrient elements (NEs), including calcium (Ca), Mg, Fe, and copper (Cu), are identified as promising alloying elements for the strengthening of Zn-based wound closure device material that simultaneously provide potential therapeutic benefit to the wound healing process during implant biodegradation process. The influence of NEs on the fundamental characteristics of biodegradable Zn are reviewed and critically assessed with regard to the mechanical properties and biodegradability requirements of different wound closure devices. The opportunities and challenges in the development of Zn-based wound closure device materials are presented to inspire future research on this rapidly growing field.

A Simple Modification of the Conventional Figure-of-Eight Sternal Closure Technique

Objective

To describe a new technique of sternal closure, modified from the conventional figure-of-eight approach, which can provide a secure closure and prevent sternal complications.

Methods

The modified technique is based on the intercalation of the caudal portion of each steel wire passed along the sternum. This is a retrospective analysis of patients operated with this modified technique at our institution between January 2014 and December 2016.

Results

One hundred and forty-three patients underwent sternal closure with the modified technique. In-hospital mortality rate was 1.4% (n=2). No sternal instability was observed at 30 days postoperatively. Two patients developed mediastinitis that required extraction of the wires.

Conclusion

Short-term results have shown that the modified sternal closure technique can be used safely and effectively, with complications rates being consistent with worldwide experience.

Retrospective analysis of the impact of sternum closure technique on postoperative comfort and rehabilitation

Introduction

Sternum closure techniques have been compared regarding biomechanics, efficacy in high-risk patients and prevention of mediastinitis or sternal dehiscence. There are no papers concerning patients' comfort and postoperative rehabilitation rate.

Aim

To establish the best surgical closure technique after midline sternotomy regarding the lowest pain level in the postoperative period and the highest rate of postoperative rehabilitation.

Material and methods

A retrospective analysis was performed on a group of 100 patients after cardiothoracic procedures which was divided into 3 subgroups according to sternal closure technique based on postoperative thoracic X-ray. To assess patients' pain and their physical activity we used a custom questionnaire. The statistical analysis was performed on the data regarding occurrence of wound healing complications risk factors, Numerical Rating Scale (NRS) for Pain score, the number of days until achieving important rehabilitations stages and the occurrence of sternal refixation.

Results

Subgroups had 35, 33 and 32 patients. The statistical analysis showed significantly lower NRS scores between the 14^th (p = 0.0012) (1.17) and 30^th (p = 0.0196) day (0.65) after the procedure in the group sutured with only single interrupted wire. There was also a significant difference in the number of days between the operation and the first time the patient could lie sideways (p = 0.0105). There was no statistically significant difference between the three groups regarding other measured factors.

Conclusions

The single wire suture provides less pain at the 14^th and 30^th day postoperatively measured on the NRS and ensures faster rehabilitation compared to sternal closing technique which involves placing both single and figure-of-8 sutures.

Recent advances in biodegradable metals for medical sutures: a critical review

Sutures that biodegrade and dissolve over a period of several weeks are in great demand to stitch wounds and surgical incisions. These new materials are receiving increased acceptance across surgical procedures whenever permanent sutures and long-term care are not needed. Unfortunately, both inflammatory responses and adverse local tissue reactions in the close-to-stitching environment are often reported for biodegradable polymeric sutures currently used by the medical community. While bioabsorbable metals are predominantly investigated and tested for vascular stent or osteosynthesis applications, they also appear to possess adequate bio-compatibility, mechanical properties, and corrosion stability to replace biodegradable polymeric sutures. In this Review, biodegradable alloys made of iron, magnesium, and zinc are critically evaluated as potential materials for the manufacturing of soft and hard tissue sutures. In the case of soft tissue closing and stitching, these metals have to compete against currently available degradable polymers. In the case of hard tissue closing and stitching, biodegradable sternal wires could replace the permanent sutures made of stainless steel or titanium alloys. This Review discusses the specific materials and degradation properties required by all suture materials, summarizes current suture testing protocols and provides a well-grounded direction for the potential future development of biodegradable metal based sutures.

Mechanism of sternotomy dehiscence

OBJECTIVES

Biomechanical modelling of the forces acting on a median sternotomy can explain the mechanism of sternotomy dehiscence, leading to improved closure techniques.

METHODS

Chest wall forces on 40 kPa coughing were measured using a novel finite element analysis (FEA) ellipsoid chest model, based on average measurements of eight adult male thoracic computerized tomography (CT) scans, with Pearson's correlation coefficient used to assess the anatomical accuracy. Another FEA model was constructed representing the barrel chest of chronic obstructive pulmonary disease (COPD) patients. Six, seven and eight trans-sternal and figure-of-eight closures were tested against both FEA models.

RESULTS

Comparison between chest wall measurements from CT data and the normal ellipsoid FEA model showed an accurate fit (P < 0.001, correlation coefficients: coronal r = 0.998, sagittal r = 0.991). Coughing caused rotational moments of 92 Nm, pivoting at the suprasternal notch for the normal FEA model, rising to 118 Nm in the COPD model (t-test, P < 0.001). The threshold for dehiscence was 84 Nm with a six-sternal-wire closure, 107 Nm with seven wires, 127 Nm with eight wires and 71 Nm for three figure-of-eights.

CONCLUSIONS

The normal rib cage closely fits the ellipsoid FEA model. Lateral chest wall forces were significantly higher in the barrel-shaped chest. Rotational moments generated by forces acting on a six-sternal-wire closure at the suprasternal notch were sufficient to cause lateral distraction pivoting at the top of the manubrium. The six-sternal-wire closure may be successfully enhanced by the addition of one or two extra wires at the lower end of the sternotomy, depending on chest wall shape.