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.     

Treatment of total sternal necrosis using the latissimus dorsi muscle flap

Complications after a median sternotomy incision, which is used currently in most cardiac and mediastinal surgical procedures, although infrequent, are serious. If sternal dehiscence follows median sternotomy, infection extends to vital underlying structures, exposing the anterior part of the heart and ascending aorta. Permanent hemorrhage, septic thrombosis, or septic perforation of prosthetic material demand soft-tissue coverage. In 5 patients with total sternum necrosis the retrosternal space was covered with a latissimus dorsi muscle flap in order to achieve stable protection of the exposed mediastinal organs.     

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.     

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.     

A rapid, secure method of sternal closure

In 1977 Robicsek(1) described a method of sternal closure that involved a double wire on each side of the sternum, with appropriate circumferential wires. Shortly thereafter, we modified that procedure, as shown in Figure 1. Only one wire is used on each side of the sternum, and fewer circumferential wires are needed. This type of sternal closure can be performed as rapidly as the usual closure of simple circumferential wire sutures and is much more secure, because the circumferential wires cannot cut through the parasternal wire. After using this method in about 100 patients with either poor sternal bone or chronic lung disease, we have encountered no subsequent sternal separation.     

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.     

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.     

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.     

Clinical morphology of the sternum]

The length, width and thickness of the sternum were measured in 74 adult specimens with the aim of optimizing the dimensions of staples used after sternotomy. This article describes the experimental procedure and presents the results. Sex differences were confined mainly to the length, with males measuring 16.5 cm, and females 15 cm. Width and thickness maxima (7.4 cm and 1.7 cm, respectively) are measured at the proximal and distal ends of the manubrium, while the width and thickness of the corpus (2.7-3.5 cm and 1.0-1.4 cm, respectively) show relatively minor differences.     

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.     

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.     

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.     

Leptin and soluble leptin receptor changes after pulmonary endarterectomy: relations to cortisol and cytokine network

Leptin is a hormone that regulates food intake. During inflammatory status, leptin may contribute to the anorexia and cachexia of infection. Pulmonary endarterectomy was used as a model of non-infectious cytokine network hyperstimulation. Leptin and soluble leptin receptor (SLR) were compared with evolution of cortisol and inflammatory cytokines in twenty-two patients with chronic thromboembolic pulmonary hypertension treated with pulmonary endarterectomy using cardiopulmonary bypass (CBP) and deep hypothermic circulatory arrest (DHCA). Leptin, SLR, cortisol, IL-beta, IL-6, IL-8, and TNFalpha concentrations in arterial blood were measured before/after sternotomy, last DHCA, separation from bypass, 12, 18, 24, 36, and 48 h after sternotomy. Mean duration of CPB was 338.2 min.; mean circulatory arrest time 39.9 min. The initial decline of leptin, SLR, TNFalpha, IL-6, and IL-8 was followed by an increase culminating 6-24 h after sternotomy. Leptin peak levels were detected 24 h after sternotomy (28.0 ng/ml, 21.9-37.6). IL-6 culminated after separation from CPB, IL-8 was highest 12 h after sternotomy. Leptin concentrations correlated with IL-6 (r=0.82), and TNFalpha (r=0.73). Large cardiovascular surgery caused a significant increase in serum leptin, indicating its acute regulation by stress factors. This effect may be secondary to the inflammatory response mediated via cytokine stimulation. Correlation between leptin and IL-6 indicates the role of IL-6 in leptin induction.     

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.     

A retrospective analysis of 48 infected sternal wound closures: delayed closure decreases wound complications

Forty-eight patients who suffered sternal wound infections following coronary artery bypass grafting were retrospectively reviewed over a 5-year period. All patients in this study had clinical signs of major infection including redness, pain, and purulence at the time of mediastinal drainage and debridement. One patient died 11 days postoperatively because of heart failure, leaving 47 patients available for long-term follow-up. All muscle flaps (pectoralis and rectus abdominis) survived completely. All wound complications were related to chest wall skin flap dehiscence or continued infection. Seventeen of 22 patients (77 percent) undergoing flap closure 4 days or less after sternal debridement and irrigation suffered wound complications. Five of these 22 patients (23 percent) had major wound complications, meaning that the wound required more than 2 months of care before healing was complete. No major wound complications and only three minor complications (12 percent) occurred in 25 patients undergoing sternal flap closure 5 days or more after mediastinal debridement and irrigation. The frequency and severity of wound complications were significantly decreased in the group of patients undergoing sternal flap closure 5 or more days after sternal drainage and debridement (p < 0.00005). In the majority of cases [29 of 47 (62 percent)], secure sternal wound closure was obtained with a single, split, medially based, right pectoralis major muscle flap.     

Radiographic and aerodynamic measures of velopharyngeal anatomy and function following Furlow Z-plasty

Recent studies have shown that the Furlow double-opposing Z-plasty has several advantages that make it an attractive procedure for cleft palate repair and treatment of velopharyngeal insufficiency in selected cases. The anatomic changes associated with this procedure have never been documented prospectively. The purpose of this study was to describe radiographic dimensions of the velopharynx and aerodynamic measures of velopharyngeal function in a group of patients before and after Furlow Z-plasty for the treatment of velopharyngeal insufficiency. Twelve consecutive patients with cleft palate and velopharyngeal insufficiency, ranging in age from 3 to 19 years, were selected as candidates for Furlow Z-plasty based on perceptual, endoscopic, and radiographic findings. Eight patients had repaired cleft palate with a residual muscle diastasis and four patients had unrepaired submucous cleft palate. Subjects received aerodynamic and cephalometric assessments before and after Z-plasty. Cephalometric x-rays were measured for velar length, thickness, and pharyngeal depth. Mean nasal airflow during pressure consonants (Vn) was calculated from pressure/flow studies, and patients were categorized as having complete closure (<10 cc/sec Vn) or incomplete closure (>10 cc/ sec Vn). After Z-plasty, there was a significant increase in velar length (p = 0.002) and velar thickness (p = 0.001). After surgery, patients with complete velopharyngeal closure had significantly greater velar length than the incomplete closure group (p = 0.05) with nearly twice the increase in length. Similarly, following surgery, the complete closure group had significantly greater thickness than the incomplete closure group (p = 0.01), with a greater postoperative increase in velar thickness (p = 0.005). Finally, there was a significant negative correlation between percent increase in length and percent increase in thickness for patients in the complete closure group (r = -0.91, p = 0.03). Findings demonstrate that following Furlow Z-plasty, patients with cleft palate and velopharyngeal insufficiency obtained significant increases in velar length and thickness. Greater velar length and greater velar thickness both were associated with complete velopharyngeal closure. Patients in the complete closure group tended to demonstrate large percent gains in either length or thickness or moderate gains in both. Patients in the incomplete closure group tended to demonstrate relatively small percent gains in both dimensions. Results suggest there may be important anatomic features (such as pharyngeal depth/velar length ratio) that can be evaluated before surgery to predict which patients may be most likely to benefit from Furlow Z-plasty as a form of treatment for velopharyngeal insufficiency.     

Balloon expansion of the pectoralis major muscle flap in sternoplasty: a biomechanical and histologic study in a rat model

The pectoralis major advancement flap is currently the most popular technique for reconstruction of the anterior chest in patients with sternotomy wounds. Recently, the SpaceMaker balloon was introduced for rapid expansion of the pectoralis major muscle intraoperatively. The aim of the present study was to investigate the biomechanical and histologic effects of this expansion technique in a rat model. The upper 2 cm of the sternum was resected in 54 male rats. Reconstruction with balloon-assisted pectoralis muscle expansion was performed in 24 rats (study group). Another 24 rats underwent reconstruction with simple muscle advancement without expansion. Submuscular insertion of a catheter for expansion, without inflation, was performed in the remaining six rats (sham group). Rats were killed either immediately or 2 to 4 weeks after surgery. Thirty-eight rats, including 16 after reconstruction with expansion, 16 after reconstruction without expansion, and six in the sham group, were killed immediately after surgery. Sixteen rats were killed 2 to 4 weeks after surgery, eight rats for each reconstruction technique. Before the animals were killed, the biomechanical properties of the muscles were tested with weights to calculate stiffness (in newtons per meter) and compliance gain (in percent). After the animals were killed, biopsy specimens were obtained for histologic analysis. Results indicated significantly lower muscle stiffness in the study group compared with the others immediately after surgery (p = 0.0000), although the difference failed to achieve statistical significance 2 to 4 weeks later (p = 0.76). In the study group, the compliance gain was 74.4 percent immediately after surgery but only 3.4 percent 2 weeks to 1 month postoperatively. Histologic examinations in all groups immediately and 2 to 4 weeks after surgery revealed regular muscle striation with no signs of inflammation. The elastic stiffness of the rat pectoralis major muscle is significantly reduced following rapid intraoperative expansion and returns to normal 2 to 4 weeks later.     

Reproducable Paraplegia by Thoracic Aortic Occlusion in a Murine Model of Spinal Cord Ischemia-reperfusion

Background Lower extremity paralysis continues to complicate aortic interventions. The lack of understanding of the underlying pathology has hindered advancements to decrease the occurrence this injury. The current model demonstrates reproducible lower extremity paralysis following thoracic aortic occlusion.Methods Adult male C57BL6 mice were anesthetized with isoflurane. Through a cervicosternal incision the aorta was exposed. The descending thoracic aorta and left subclavian arteries were identified without entrance into pleural space. Skeletonization of these arteries was followed by immediate closure (Sham) or occlusion for 4 min (moderate ischemia) or 8 min (prolonged ischemia). The sternotomy and skin were closed and the mouse was transferred to warming bed for recovery.  Following recovery, functional analysis was obtained at 12 hr intervals until 48 hr.Results Mice that underwent sham surgery showed no observable hind limb deficit. Mice subjected to moderate ischemia for 4 min had minimal functional deficit at 12 hr followed by progression to complete paralysis at 48 hr. Mice subjected to prolonged ischemia had an immediate paralysis with no observable hind-limb movement at any point in the postoperative period. There was no observed intraoperative or post operative mortality.Conclusion Reproducible lower extremity paralysis whether immediate or delayed can be achieved in a murine model. Additionally, by using a median sternotomy and careful dissection, high survival rates, and reproducibility can be achieved.     

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.     

Dacron fabric-enveloped hydroxyapatite prosthesis for sternal tumor defect: an autopsy report

A 38-year-old housewife with solitary plasmacytoma of the manubrium who underwent a subtotal sternectomy treated by resection of the lesion is reported. This was followed by replacement with a Dacron fabric-enveloped hydroxyapatite prosthesis. The Dacron fabric was sutured to the surrounding tissues, and then the clavicle was passed through the cylindrical-shaped Dacron fabric to form a sternoclavicular joint capsule. The patient returned to her daily life 3 months after the operation. She had no trouble in her daily living, without any dislocation of the sternoclavicular joints or any displacement of the artificial sternum. The autopsy examination about 1 year after the operation showed that the Dacron fabric enveloping the artificial sternum became stronger with time. The sternoclavicular joint also was stably fixed, and the Dacron fabric fulfilled its function as an artificial articular capsule and biologic fixation of the surrounding supporting tissues.