REPAIR OF BROKEN WIRE DURING STERNAL CLOSURE

A frustrating experience for thoracic surgeons is the breakage of a sternal wire at the time it is being tightened to close a median sternotomy. A simple technique to repair broken sternal wires and allow continuation of the procedure without opening the sternum is described.     

Internal fixation of the sternum in median sternotomy dehiscence.

Sternal dehiscence may be defined as separation of the bony sternum and manubrium following median sternotomy. It may occur at any time postoperatively and has various etiologies. Restoration of sternal integrity in sternal dehiscence is a challenging problem, particularly when associated with deep-seated infection. This report reviews a single-stage technique that virtually eliminates the infected sternotomy wound and provides anatomic reduction and stabilization of the sternum. Complete debridement of infected and/or nonviable soft tissue, bone, and cartilage is followed by pulse irrigation. Parallel stainless steel mandibular reconstruction plates are then placed on each side of the remaining sternum and wired together. One or more transmanubrial compression plates may be added. Bilateral pectoralis major musculocutaneous flap advancement and primary skin closure is performed over two to three closed suction drains. From January of 1994 to July of 1996, this technique was used by the same surgeon in 26 male and 4 female patients aged 43 to 78 years (mean = 61). Indications for the operation were sternal dehiscence with infection (osteomyelitis and/or mediastinitis) in 14 patients and sternal dehiscence without infection in 16 patients. All patients survived to discharge with mean time on the ventilator, intensive care unit length of stay, and postoperative length of stay of 0.7, 2, and 8 days, respectively. Choice and duration of antibiotics were based on culture results and operative findings. Subsequent hardware removal was necessary in one patient for hardware loosening and three patients for late periplate infection. A closed wound was eventually achieved in all 30 patients, and sternal stability was restored in 29 patients. In the management of sternal dehiscence, the described technique of internal fixation can provide anatomic sternal reduction and stabilization, elimination of infection, and wound closure in a single-stage operation. Successful outcomes were achieved despite the presence of severe infection.     

First Evidence of Sternal Wound Biofilm following Cardiac Surgery

Management of deep sternal wound infection (SWI), a serious complication after cardiac surgery with high morbidity and mortality incidence, requires invasive procedures such as, debridement with primary closure or myocutaneous flap reconstruction along with use of broad spectrum antibiotics. The purpose of this clinical series is to investigate the presence of biofilm in patients with deep SWI. A biofilm is a complex microbial community in which bacteria attach to a biological or non-biological surface and are embedded in a self-produced extracellular polymeric substance. Biofilm related infections represent a major clinical challenge due to their resistance to both host immune defenses and standard antimicrobial therapies. Candidates for this clinical series were patients scheduled for a debridement procedure of an infected sternal wound after a cardiac surgery. Six patients with SWI were recruited in the study. All cases had marked dehiscence of all layers of the wound down to the sternum with no signs of healing after receiving broad spectrum antibiotics post-surgery. After consenting patients, tissue and/or extracted stainless steel wires were collected during the debridement procedure. Debrided tissues examined by Gram stain showed large aggregations of Gram positive cocci. Immuno-fluorescent staining of the debrided tissues using a specific antibody against staphylococci demonstrated the presence of thick clumps of staphylococci colonizing the wound bed. Evaluation of tissue samples with scanning electron microscope (SEM) imaging showed three-dimensional aggregates of these cocci attached to the wound surface. More interestingly, SEM imaging of the extracted wires showed attachment of cocci aggregations to the wire metal surface. These observations along with the clinical presentation of the patients provide the first evidence that supports the presence of biofilm in such cases. Clinical introduction of the biofilm infection concept in deep SWI may advance the current management strategies from standard antimicrobial therapy to anti-biofilm strategy.     

The integrated approach to suppurative mediastinitis: rewiring the sternum over transposed omentum

Acute mediastinitis after cardiopulmonary procedures remains a devastating complication and a challenge to the reconstructive surgeon. A review of the literature and our own experience confirm the need for early aggressive drainage followed by timely reconstruction. In carefully selected patients, the sternum may be reclosed, provided that omental tissue has been transposed into the defect between the myocardium and the posterior cortex of the sternum. The technique is outlined and the results are analyzed and compared with three additional patient subgroups: (1) sternal wounds rewired over drains, (2) sternal wounds rewired with drains and irrigation catheters, and (3) wounds closed by sternal excision and muscle-flap transposition. To date, nine omental transfers have been performed with complete success. Mediastinal drainage routinely ceases after 3 to 5 days, and hospitalization has averaged 10 to 14 days. Early open debridement allows establishment of drainage and permits close evaluation of the character of the bony sternum. Muscle flaps may then be used in those patients with multiply fractured or frankly necrotic sternal tissue, while sternal closure over omental flaps may be used in all other patients. Adherence to this protocol has allowed for bacteriologic control of the wound, minimal morbidity, and no mortality.     

Use of the SpaceMaker balloon in sternal wound closure: comparison with other techniques.

Sternal wound infection is surgically treated by debridement of the infected sternum and closure of the defect with a muscular flap. These operations tend to be long, stressful, and time-consuming and to involve heavy blood loss. To facilitate wound closure, the SpaceMaker balloon was applied intraoperatively to expand the pectoralis major muscles and enable tensionless closure with musculocutaneous flaps. The aim of the present study was to compare the effectiveness and feasibility of this technique with a variety of others described in the literature. The study population consisted of 40 consecutive patients with sternal wound infection following median sternotomy who were treated with the advancement flap, turnover flap, transposition flap, or SpaceMaker balloon-assisted advancement flap technique (n = 10 each). The balloon-assisted technique was associated with a shorter length of operation and fewer blood transfusions than the other methods. Furthermore, there was no need for reoperation and there were no cases of skin necrosis. In conclusion, closure with the SpaceMaker balloon-assisted bilateral pectoralis major musculocutaneous flap may serve as an adjunctive measure in the treatment of sternal wound infection. This technique seems to have advantages over simple pectoralis major musculocutaneous advancement, particularly for midsternal wounds.     

In-vivo analysis of sternal angle,sternal and sternocostal kinematics in supine humans during breathing

This paper aims at contributing to the understanding of the combination of in vivo sternum displacement, sternal angle variations and sternocostal joints (SCJ) kinematics of the seven first rib pairs over the inspiratory capacity (IC). Retrospective codified spiral-CT data obtained at total lung capacity (TLC), middle of inspiratory capacity (MIC) and at functional residual capacity (FRC) were used to compute kinematic parameters of the bones and joints of interest in a sample of 12 asymptomatic subjects. 3D models of rib, thoracic vertebra, manubrium and sternum were processed to determine anatomical landmarks (ALs) on each bone. These ALs were used to create local coordinate system and compute spatial transformation of ribs and manubrium relative to sternum, and sternum relative to thoracic vertebra. The rib angular displacements and associated orientation of rotation axes and joint pivot points (JPP), the sternal angle variations and the associated displacement of the sternum relative to vertebra were computed between each breathing pose at the three lung volumes. Results can be summarized as following: (1) sternum cephalic displacement ranged between 17.8 and 19.2 mm over the IC; (2) the sternal angle showed a mean variation of 4.4° ± 2.7° over the IC; (3) ranges of rib rotation relative to sternum decreased gradually with increasing rib level; (4) axes of rotation were similarly oriented at each SCJ; (5) JPP spatial displacements showed less variations at first SCJ compared to levels underneath; (6) linear relation was demonstrated between SCJ ROMs and sternum cephalic displacement over the IC.     

Treatment of sternal nonunion with the Dall-Miles cable system

We have used this technique in two patients. One had early sternal dehiscence with presternal infection, and the other had late sternal nonunion. Uncomplicated sternal union was achieved in both patients. The cables were nonpalpable in both patients, but they were removed in one patient at that patient's request. This method of using Dall-Miles cerclage cables is a straightforward and efficacious method of open reduction and internal fixation of the sternum. It is indicated for patients with chronic sternal nonunion or early postoperative separation of the sternal fragments and may be used even in the presence of an infection limited to the presternal space after adequate debridement and irrigation have been performed. Any recurrent superficial infection, although unlikely, can be cured by hardware removal after osseous union has been obtained. For sternal separation without fractures, four cables may simply be placed around the sternal halves and their tension increased. In the case of sternal fractures, the cables may be placed in figures of eight or in other woven configurations as needed for each individual case.     

Complete Thymectomy in Adult Rats with Non-invasive Endotracheal Intubation

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and pneumothorax from pleural disruption can result in a significant mortality rate. This protocol is a simple method of rat thymectomy that utilizes a mini-sternotomy and endotracheal intubation. Intubation is accomplished with a non-invasive and easily reproducible method and allows for positive pressure ventilation to prevent pneumothorax and a controlled airway that allows sufficient time for careful thymus dissection to minimize pleural disruption. A 1.5 cm sternal incision decreases contact with mediastinal vessels and pleura, while still providing full visualization of the thymus. Following exposure of the mediastinum, the thymus is removed by blunt dissection under magnification. The pleural space is then sealed by suture closure of the pre-tracheal muscles followed by the application of surgical glue. The thorax is then closed by suture closure of the sternum, followed by suture closure of the skin. All thymectomies were complete as evidenced by immunohistochemical (IHC) staining of mediastinal tissue, and absence of naïve T-cells by flow cytometry, and the procedure had a 96% survival rate. This method is suitable when complete thymectomy with minimal complications is desired for further immunological studies in athymic adult rats.     

Morphometric analysis of variation in the sternum with sex and age

Age and sex‐related variations in sternum morphology may affect the thoracic injury tolerance. Male and female sternum size and shape variation was characterized for ages 0–100 from landmarks collected from 330 computed tomography scans. Homologous landmarks were analyzed using Procrustes superimposition to produce age and sex‐specific functions of 3D‐sternum morphology representing the combined size and shape variation and the isolated shape variation. Significant changes in the combined size and shape variation and isolated shape variation of the sternum were found to occur with age in both sexes. Sternal size increased from birth through age 30 and retained a similar size for ages 30–100. The manubrium expanded laterally from birth through age 30, becoming wider in relation to the sternal body. In infancy, the manubrium was 1.1–1.2 times the width of the sternal body and this width ratio increased to 1.6–1.8 for adults. The manubrium transformed from a circular shape in infancy to an oval shape in early childhood. The distal sternal body became wider in relation to the proximal sternal body from birth through age 30 and retained this characteristic throughout adulthood. The most dramatic changes in sternum morphology occur in childhood and young adulthood when the sternum is undergoing ossification. The lesser degree of ossification in the pediatric sternum may be partly responsible for the prevalence of thoracic organ injuries as opposed to thoracic skeletal injuries in pediatrics. Sternum fractures make up a larger portion of thoracic injury patterns in adults with fully ossified sternums. The lack of substantial size or shape changes in the sternum from age 30–100 suggests that the increased incidence of sternal fracture seen in the elderly may be due to cortical thickness or bone mineral density changes in the sternum as opposed to morphological changes. J. Morphol. 275:1284–1299, 2014. © 2014 Wiley Periodicals, Inc.     

Endoscopic correction of pectus excavatum

Endoscopic surgery is minimally invasive and can be used to achieve superior cosmetic results. Conventional correction of pectus excavatum results in a long scar. Correction by use of endoscopic surgery involves a smaller skin incision. In this study, endoscopic correction of pectus excavatum was performed in 20 cases. A small transverse skin incision was made above the xyphoid process. A wide area beneath the pectoralis major muscle was dissected under endoscopic visualization. Subperichondrial resection was performed under direct visualization when possible. Subperichondrial resection of the third or fourth rib was performed under endoscopic visualization. Ravitch's chondrotomy of the second or third rib was performed under endoscopic visualization. Endoscopy was also useful for sternal elevation, with minimal risk of pleural perforation. Kirschner wire was inserted percutaneously under the sternum to prevent postoperative paradoxical respiration. In all cases, the postoperative course was uneventful. The advantages of endoscopic pectus excavatum correction are a short scar, control of bleeding, safe dissection of the pleura from the sternum without the risk of pleural perforation, and ease of sternal elevation without injury to the intramammary vessels. However, the endoscopic operation is long and is not useful in adults because subperichondrial resection in adults is difficult to perform.     

Disturbances in cardiac rhythm caused by the removal of temporary pacemaker wires

The effects of temporary pacemaker wire removal on cardiac rhythm were studied in 22 open-heart surgery patients who had temporary pacemaker wires implanted at the time of chest wall closure. During wire removal, 16 patients developed premature ventricular contractions (PVCs), most commonly occurring as single PVCs, and less often as ventricular couplets. The authors recommend that external pacemaker wire removal be accompanied by electrocardiographic monitoring or at least by a short period of careful clinical observation.     

USE OF THE SUTURE LOCK PLATE FOR STERNAL APPROXIMATION IN CHILDREN

Sternal closure after median sternotomy in the pediatric age group may be accomplished with non-resorbable sutures or stainless steel wire. The former has the disadvantages of chronic sinus formation and the latter may either break or cause pressure on the skin. The Pill-Wolvek Suture Lock Plate was used as an alternative method in 26 patients aged from seven days to six years. It has the advantage of greater strength and avoids the problem of prominent twisted wire ends. Healing has been excellent and there have been no complications attributed to the wires.     

Real mineral density of the sternum

Mineral density of the sternum is insufficiently known. The aim of this research was to investigate mineralisation of the sternum and collect normative data on mineral density of the standard male and female sternum in elderly people (average age of female samples was 64 and male's was 62 years). The research was conducted on 93 cadaveric sternums, 56 male and 37 female samples. To determine regional mineral density of the sternum each sample was cut into six bony segments (Figure 1). Mineral density of every segment was determined using the method of ashing. Male sternums were on average denser than female ones in all segments. Average mineral density of the manubrium in women was 0.169 g/cm3 and 0.220 g/cm3 in men. Average mineral density of the body of the sternum also showed existence of sex difference; it was 0.160 g/cm3 in women and 0.227 g/cm3 in men. Both male and female sternums showed identical mineral density distribution. Mineral density of the manubrium and the body was roughly equal, while the analysis of longitudinal segments showed that the central part of both the manubrium and the body of the sternum was denser than lateral parts. Complex determination of the real mineral density for defined segments of the sternum and analysis of the obtained results were used to create the map of mineral density of the sternum in men and women (Figure 2). Maximum density values were four times greater than minimum density values for analysed samples. These data showed that osteoporosis also occurs on the sternum. Loss of structure and lower mineral density decrease the sternum quality and increase the risk of sternal dehiscence after median sternotomy.     

鸟类胸骨的形态结构多样性及其与飞行能力的关系

不同生态类型的鸟类,其胸骨具有多样性的特征,同时还与鸟类的飞行能力强弱有卣接的关系.根据胸骨形态学特征差异及数据的统计分析得出:鸟类胸骨的前侧突、后侧突的排列方式以及后缘凹13的形态是判断其生态习性的有效形态标志.此外,当胸骨深度加大,且胸骨宽度不断加长的鸟类其飞行能力也加强;反之,胸骨的长度加长,深度、宽度渐小的鸟类,其飞行能力较弱或已经丧失飞行能力.     

A 3-year experience of a minimally invasive technique for correction of pectus excavatum in Croatia

The aim of this study was to assess the early results of a three-year experience with the minimally invasive correction of pectum excavatum, which requires no cartilage incision or excision, and no sternal osteotomy. Since 2001 we have performed 35 minimally invasive pectus excavatum procedures at our hospital. A convex steel bar is inserted under the sternum through small bilateral incisions, and removed after 2 years when permanent remolding had occured, the bar is removed. Complications were pneumothorax in 5 patients (only 1 required a thoracostomy tube, the other 4 resolved spontaneously), pneumonia in 3 patients, and bar displacement in 1 patient. The mean follow-up was 3 months to 3 years. Initial excellent results were maintained in 28 patients (normal postoperative chest), good results in 5patients (mild residual pectus) and poor in 2 patients (severe recurrence requiring further treatment). Poor results occurred because the steel bar was too soft in 1 patient, and the sternum too soft in 1 patient with Marfan's syndrome. Our early results with the minimally invesive technique without cartilage incision and resection or sternal osteotomy showed that the procedure is effective with excellent preliminary results.     

西安市青年学生胸骨长与身长的关系

本文对1980年测量的西安在校汉族青年学生1585名(男863,女722),年龄16-24岁,按年龄性别分组,计算了身长和胸骨长的均值、胸骨长占身长的百分数、身长与胸骨长的比值、身长、胸骨长指数,并提出了由胸骨长推算身长的回归方程。     

Analysis of the electrophoretic migration of DNA frayed wires

We analyzed the electrophoretic behaviour of the unusual multi-stranded DNA complexes, frayed wires, in polyacrylamide gels under non-denaturing conditions. Frayed wires arise from the association of several strands of a parent oligonucleotide that possesses long terminal runs of consecutive guanines. According to the structural model proposed for frayed wires, there are two distinct conformational domains, a guanine stem and single stranded arms displaced from the stem. The presence of the two domains affects the electrophoretic migration of the frayed wires, resulting in a greater retardation compared to that of double stranded DNA of the same molecular weight. The degree of retardation is determined by the relative length of the stem and the arms; the complexes with longer arms display a stronger dependence on the total molecular weight. Reptation plots (mobility x molecular weight vs. molecular weight) were used to study the electrophoretic behaviour of frayed wires that arise from the different parent oligonucleotides. The plots are unique for each type of frayed wire. The characteristic parameter, the position of the maximum of the reptation plot, depends on the type of the frayed wire as well as the total gel concentration. The plots become similar when we replot the mobility data taking into account only the single stranded arms of the frayed wires. The positions of the maximum and the overall shape are very close for the four types of frayed wires studied.     

Training cattle to control by electric fences

Since cattle learn respect for electric fences, it may be possible to use single electric wires as permanent fences on beef-cattle properties. Two experiments are reported in this paper. The first investigated a method of training inexperienced cattle in a small yard before release to paddocks fenced with a single wire. The training yard consisted of a strong conventional fence with a single electric wire attached. It confined animals in a small area, thus encouraging them to investigate, receive shock and learn respect. After a day of such training, the animals were automatically photographed at each approach to a single wire in a test paddock and compared with an untrained group in a similar test paddock. Although no animals broke through in either group, it is clear that trained animals more quickly recognized the wire and showed respect by not touching it.The second experiment demonstrated the great respect cattle had for a single electrified wire after training, because it prevented hungry heifers from going to eat hay which they had been conditioned to eat.It is concluded that training is simple and provides a controlled learning period to give increased respect for electrified wires and to minimize the risk of animals breaking through when first released to paddocks with electrified boundaries.     

Morphometric analysis of the sternum

Sternum has a great clinical significance, considering that median sternotomy is the most common surgical approach used in cardiac surgery. The aim of this study is to standardize the sternum according to size, shape and sex and to obtain ranges of the "standard sternum". The study was done on 55 male and 35 female sterna of the average age of 65. Complex morphometric analysis of breadth, length and thickness of the sterna were performed on sternal segments which were defined by costal notches. Morphometric analysis shows that the general sternum structure in the females and in the males is equal. The standard dimensions of female and male sternum were determined. Standardization according to shape suggests that there is one standard sternum shape present in more than 2/3 of analysed samples of both sexes.