Sternal Bands Research Articles

Evolutionary assembly and disassembly of the mammalian sternum

Evolutionary transitions are frequently associated with novel anatomical structures,1 but the origins of the structures themselves are often poorly known. We use developmental, genetic, and paleontological data to demonstrate that the therian sternum was assembled from pre-existing elements. Imaging of the perinatal mouse reveals two paired sternal elements, both composed primarily of cells with lateral plate mesoderm origin. Location, articulations, and development identify them as homologs of the interclavicle and the sternal bands of synapsid outgroups. The interclavicle, not previously recognized in therians,2 articulates with the clavicle and differs from the sternal bands in both embryonic HOX expression and pattern of skeletal maturation. The sternal bands articulate with the ribs in two styles, most clearly differentiated by their association with sternebrae. Evolutionary trait mapping indicates that the interclavicle and sternal bands were independent elements throughout most of synapsid history. The differentiation of rib articulation styles and the subdivision of the sternal bands into sternebrae were key innovations likely associated with transitions in locomotor and respiratory mechanics.3,4 Fusion of the interclavicle and the anterior sternal bands to form a presternum anterior to the first sternebra was a historically recent innovation unique to therians. Subsequent disassembly of the radically reduced sternum of mysticete cetaceans was element specific, reflecting the constraints that conserved developmental programs exert on composite structures.

Ascending aorta graft pseudoaneurysm and aortobronchial fistula caused by a fractured sternal wire: a case report

BackgroundPseudoaneurysm of ascending aorta is a rare but serious complication of cardiovascular surgeries and it infrequently occurs in the normal prosthetic graft materials. We share our experience with an unusual case of ascending aorta Dacron graft pseudoaneurysm caused by a fractured sternal wire.Case presentationA 34-year-old man, known case of Marfan syndrome, with history of two prior aortic surgeries for aneurysm of ascending aorta, arch and thoracoabdominal aorta, presented with hemoptysis. The hemoptysis originated from an aortobronchial fistula secondary to a huge ascending aorta Dacron graft pseudoaneurysm. The graft erosion and subsequent pseudoaneurysm was caused by a fractured sternal wire. Surgical repair of the pseudoaneurysm was performed successfully and a Gore-tex patch was placed behind the sternum over the graft to prevent further direct contact of the wire and the graft.ConclusionSternal wires can damage the adjacent vascular grafts and lead to fatal complications such as pseudoaneurysm formation. Thus, preventive measures such as using sternal bands and placing a covering layer between the sternal wires and aortic grafts are recommended in patients with dilated or replaced ascending aorta.

Titanicking the Clamshell. Anchoring the Bilateral Thoracosternotomy Incision with Titanium Plates, Screws and Sternal Band. Our Experience in Fifty Consecutive Patients of Double Lung Transplantation

Purpose Clamshell incision for double lung transplantation offers unmatched advantages . But prolonged immunosuppresion therapy along with corticosteroids can lead to sternal healing abnormalities, overriding, gaping and cut through injuries on usage of sternal wires for closure . We have modified sternal closure technique using H shaped titanium plates, screws and sternal bands. The review of data on such closure of sternum in fifty consecutive lung transplant shows reduced healing complications of the sternum. Methods Our thoracic organ transplant services team has done 142 double lung transplantation from february 2017 to till date. We have been using H shapped ladder type titanium plates with 2.4 mm cancellous self tapping screws and a single sternal band. We retrospectively reviewed and compared data between fifty conventional closure (stainless steel wire technique) versus titanium plate and sternal band closure in fifty recipients. Results We observed that 15 patients (30%) in conventional Closure group had some sternal healing complications such as over riding(4 patients 8%), complete dehiscence(3 patients 6%), wire cut through(3 patients 6%)wire protruberance (3 patients 6%)and sternal mobility (2 patients 4%). Only one patient (2%)in titanium plate closure had sternal mobility, there were no other complications in the latter subset. Conclusion Titanium plate closure, has lesser healing complications of sternum, making this method a regular closure strategy for all our double lung transplantation recipients.

The therian sternum at the lateral somitic frontier: Evolution of a composite structure

AbstractThe mammalian sternum plays key roles in structural support, locomotion and ventilation, but its evolutionary history has rarely been addressed. Unlike most other synapsids, the therian presternum lacks a discreet interclavicle, and the mesosternum is composed of a series of sternebrae. Here, CT scans of fossil and living therians are used to confirm that the therian presternum incorporates multiple elements, including the interclavicle and the anteriormost sternal bands of ancestral synapsids. A previously unrecognized transitional element that articulates with rib 1 is variably present and is hypothesized to permit the direct integration of the first rib and the sternum, despite their origins in different developmental domains. Sternebrae are found at sites where primaxial ribs interact directly with the abaxial sternum and locally inhibit skeletal maturation. Both presternal fusion and mesosternal subdivision are the products of small developmental changes that allowed the adaptation of ancestral structures to the lifestyles of therians.

A randomized trial comparing the effects of sternal band and plate fixation of the sternum with that of figure-of-8 wires on sternal edge motion and quality of recovery after cardiac surgery.

We sought to compare the effects of conventional wire cerclage with that of the band and plate fixation of the sternum. A parallel randomized open-label trial with 1:1 allocation ratio compared healing after adult cardiac surgery using 'figure-of-8' stainless steel wire cerclage or a band and plate system (plates). The primary end point was maximal sternal edge displacement during active coughing of ≥2 mm in ≥2 of 4 sites measured with ultrasound by 2 assessors blinded to the other at 6 weeks postoperatively. Secondary end points at 12 weeks included ultrasound assessment, computed tomography (CT) scan and multidimensional assessment of quality of recovery using the Postoperative Quality of Recovery Scale. Of 50 patients, 26 received plates and 24 wires. Two patients died and 1 withdrew consent leaving 25 plates and 22 wires for primary end point analysis. Operations included 37 coronary, 5 valve and 8 combined coronary and valve procedures. At 6 weeks, less sternal movement was observed in patients with plates than those with wires, 4% (1/25) vs 32% (7/22), P = 0.018. Agreement between observers was high, kappa = 0.850. At 12 weeks, less ultrasound motion was seen in patients with plates, 0% (0/23) than those with wires, 25% (5/20), P = 0.014. Recovery from pain was higher for patients with plates 92% (22/24) than those with wires 67% (14/21), P = 0.004. CT bone edge separation was less for plates 38% (9/24) than wires 71% (15/21), P = 0.036. CT mild bone synthesis or greater was similar between patients with plates 21% (5/24) and wires 14% (3/21), P = 0.71. Patients receiving the band and plate system had significantly less sternal edge motion than those receiving wires, 6 and 12 weeks after cardiac surgery and experienced less pain. clinicaltrials.gov NCT03282578.

A comparative study between the use of steel wires and sternal bands for sternal closure following cardiac surgery

A comparative study between the use of steel wires and sternal bands for sternal closure following cardiac surgery

PHACES syndrome with Ectopia cordis

PHACES syndrome is an acronym for, P, posterior fossa anomalies as Dandy- Walker malformation; H, hemangioma (capillary segmental faces); A, arterial lesions of the head and neck (the most common ones include aberrant origin or course, hypoplasia, dysplasia and agenesis); C, cardiac abnormalities as coarctation of aorta; E, abnormalities of the eye and S, sternal defect. The constellation of findings of PHACES syndrome may vary significantly in different patients. Complete sternal cleft with ectopia cordis is an extremely rare congenital anomaly failed ventral migration and fusion of the two-lateral mesodermal sternal bands between the sixth and ninth weeks of gestation. We are reporting a rare case of PHACES syndrome, with partial ectopia cordis as a midline defect, who is in our follow up since birth. Survival of the child without surgical intervention with epithelialization over the defect and Leucomatous corneal opacity are interesting findings.

Surgical management of Sternal wound infection post cardiac surgery "single surgeon experience"

Results A consultant non cardiac thoracic surgeon managed 146 patients with DSWI and /or dehiscence. Nine patients were excluded due to sternal dehiscence with no evidence of gross infection and also negative wound culture. Eighty four patients were female. According to El Oakley classification, Type I, II, III, IV, V were 8, 2, 79,5,43, consequently. All patients evaluated by CT scan before intervention or after 1st operation. Patients had soft tissue debridement, with removal of wires in one or staged operation combined with mediastinotomy, mediastinal irrigation and debridement. Twelve patients had near total sternectomy, one upper sternectomy and one patient had sternoclavicular joint resection. One hundred four patient had partial sternectomy (74 longitudinal and 30 transverse sternectomy. Chondrectomy was done in 44 and decortication in 6. Twelve patient had rewiring. Bone stabilization was done by Zipfix or Sternal band +/_ wires in 12 and Titanium plate in 6. Only two patients had negative pressure wound therapy (NPWT) as a bridge to reconstruction. At the end 20 patients had delay simple closure of skin. In 113 patients a total of 163 pectoral muscle flap including: 36 right pectoral major muscle turnover flap (RPMMTF); 53 combined RPMMTF plus left advancement pectoral muscle flap (LTPMMFC); 14 local right or left PMMF were done. We used 4 rectus abdominis flap, 2 omental flap, and breast flap. Twenty nine patients had reoperation after reconstruction. Nine had recurrence osteomyelitis and /or chondritis. One patient had mediastinitis and 9 had skin flap necrosis. Remnant of pace wire was the cause of recurrent infection in 2. Five patients had rewiring or reconstruction and one patient had operation due to GI bleeding. Hospital mortality rate was 8.21% (12 patients were died. Patients had followed for a mean of 40.3 months and 3 years mortality rate was 13.69%.

Morphogenesis of the Manubrium of Sternum in Human Embryos: A New Concept

To revisit many theories on fetal development of the manubrium of the sternum, we examined 25 mid-term fetuses at 6-9 weeks of gestation. The initial developmental stage of the manubrium was characterized by a distinct interclavicular mesenchyme that was continuous with the developing clavicles. Because parts of the clavicle in which endochondral ossification occurs originate from the neural crest, the interclavicular mesenchyme seems to be of the same origin. The sternal bands, possibly of the lateral plate origin, were restricted at the anterior ends of the ribs in the paired thoracic walls. The interclavicular mesenchyme extended caudally and laterally to reach the anterior ends of the first ribs, and thus the interclavicular mesenchyme expanded into the intercostoclavicular mesenchyme. Then, the primitive manubrium was delimited by the sternoclavicular joint and its related ligaments, all of which developed from the interclavicular and intercostoclavicular mesenchymes. Although the first ribs were attached to the intercostoclavicular mesenchyme, the former was vimentin-negative in contrast to the latter, positive mesenchyme. Soon afterwards, the small upper end of the sternal bands was integrated into the intercostoclavicular mesenchyme to form the primitive manubrium. The infrahyoid muscles and their supplying nerves maintained a close topographical relation to the interclavicular or intercostoclavicular mesenchyme, whereas the pectoralis major muscle kept attachments to the sternal bands. Consequently, the manubrium of sternum appeared to develop in a complex way at a junction area between derivatives of the neural crest, lateral plate, and somite.

Smad6 is essential to limit BMP signaling during cartilage development

Bone morphogenetic protein (BMP) signaling pathways regulate multiple aspects of endochondral bone formation. The importance of extracellular antagonists as regulators of BMP signaling has been defined. In vitro studies reveal that the intracellular regulators, inhibitory Smads 6 and 7, can regulate BMP-mediated effects on chondrocytes. Although in vivo studies in which inhibitory Smads were overexpressed in cartilage have shown that inhibitory Smads have the potential to limit BMP signaling in vivo, the physiological relevance of inhibitory Smad activity in skeletal tissues is unknown. In this study, we have determined the role of Smad6 in endochondral bone formation. Loss of Smad6 in mice leads to defects in both axial and appendicular skeletal development. Specifically, Smad6-/- mice exhibit a posterior transformation of the seventh cervical vertebra, bilateral ossification centers in lumbar vertebrae, and bifid sternebrae due to incomplete sternal band fusion. Histological analysis of appendicular bones revealed delayed onset of hypertrophic differentiation and mineralization at midgestation in Smad6-/- mice. By late gestation, however, an expanded hypertrophic zone, associated with an increased pool of proliferating cells undergoing hypertrophy, was evident in Smad6 mutant growth plates. The mutant phenotype is attributed, at least in part, to increased BMP responsiveness in Smad6-deficient chondrocytes. Overall, our results show that Smad6 is required to limit BMP signaling during endochondral bone formation.

Use of steel bands in sternotomy closure: implications in high-risk cardiac surgical population

A retrospective-prospective descriptive and comparative study of two sternal closure techniques in a population of 621 patients divided into: group A, steel band closure (n=300) and group B, conventional technique closure (n=321), was carried out between January 2005 and December 2007 in order to describe and compare the results of both techniques in high-risk patients for sternal dehiscence and mediastinitis. Differences between both groups and association with risk factors were obtained using non-parametric tests for statistical analysis. No complications or mortality related to the use of the steel sternal bands were found. A statistically significant difference was found in the frequency of sternal dehiscence between both groups (P=0.022) in favor of group A. Although the frequency of mediastinitis was higher in group B, a statistically significant difference could not be established in terms of this complication. Sternal dehiscence was found to be a risk factor for mediastinitis. This study demonstrates that the use of steel bands for median sternotomy closure is a safe, reliable and reproducible technique. The frequency of sternal dehiscence significantly decreases with this technique in high-risk patients.

Sternal Bands for Closure of Midline Sternotomy Leads to Better Wound Healing

Midline sternotomy is the most common incision for cardiac surgery, but problems of wound healing and sternal instability are still matters of concern. The use of stainless steel wires only was compared with the use of wires plus sternal bands for closure of midline sternotomy wounds in a 2-year period. Of 370 patients in whom only stainless steel wires were used, 14 (3.78%) required re-operation for dehiscence. Only 3 (0.76%) of 395 patients in whom sternal bands were also used, required re-operation for dehiscence. The difference was highly significant. It was concluded that use of sternal bands leads to a more stable union.

Isolated cleft sternum: Neonatal surgical treatment

Isolated cleft sternum is a rare congenital defect of the anterior chest wall and is the result of failed ventral midline fusion of sternal bands. We present two cases operated 18 and 24 days after birth with satisfactory results. Surgery is indicated to protect the heart and mediastinal contents.

Fatigue testing median sternotomy closures

Sternal dehiscence is commonly due to wire cutting through bone. With a biological model, we measured the rate of cutting through bone, of standard steel wire closure, peristernal steel wire, figure-of-eight closure, polyester and sternal bands sternotomy closure techniques. Polyester, figure-of-eight, peristernal and sternal band closures were tested against standard closure eight times using adjacent paired samples, to eliminate biological variables. Fatigue testing was performed by a computerized materials-testing machine, cycling between loads of 1 and 10 kg. The displacements at maximum and minimum loads were measured during each cycle. Cutting through, manifested by the displacement at the maximum load between the 1st and 150th cycles was measured. The percentage cut-through of each closure method versus standard closure was calculated. The differences in the displacement between each of the polyester (1.01 mm), figure-of-eight (0.52 mm), peristernal (0.72 mm) and sternal band (0.66 mm) groups versus standard closure (0.22, 0.22, 2.1, 3.2 mm) in the paired samples were statistically significant (Student's paired t-test; P<0.01). There were statistically significant differences in the percentage cut-through of polyester, figure-of-eight, peristernal and sternal bands (ANOVA, P<0.001), versus standard closure. In our sheep sternum model, we have quantified the differing rate of cutting through bone of five types of median sternotomy closure techniques. We have controlled for bone variables by testing each closure versus standard closure using paired adjacent bone samples. Peristernal and sternal band closure techniques are significantly superior to standard closure. The use of polyester and figure-of-eight closures requires caution.

Mice lacking Bmp6 function.

Bmp6, a member of the 60A subgroup of bone morphogenetic proteins (BMPs), is expressed in diverse sites in the developing mouse embryo from preimplantation stages onwards. To evaluate roles for Bmp6 signaling in vivo, gene targeting was used to generate a null mutation at the Bmp6 locus. The resulting Bmp6 mutant mice are viable and fertile, and show no overt defects in tissues known to express Bmp6 mRNA. The skeletal elements of newborn and adult mutants are indistinguishable from wild-type. However, careful examination of skeletogenesis in late gestation embryos reveals a consistent delay in ossification strictly confined to the developing sternum. In situ hybridization studies in the developing long bones and sternum show that other BMP family members are expressed in overlapping domains. In particular we find that Bmp2 and Bmp6 are coexpressed in hypertrophic cartilage, suggesting that Bmp2 may functionally compensate in Bmp6 null mice. The defects in sternum development in Bmp6 null mice are likely to be associated with a transient early expression of Bmp6 in the sternal bands, prior to ossification. These sternal defects are slightly exacerbated in Bmp5/6 double mutant animals.

Congenital Bifid Sternum

Sternal clefting is an unusual congenital anomaly that should be repaired in early infancy. Early surgery is facilitated by a highly compliant bony thorax. The surgical technique is described, including the (1) removal of a wedge at the confluence of the two lateral sternal bands to allow their apposition, (2) intraoperative assessment of pulmonary compliance and central venous pressure, (3) use of bilateral pectoral flaps, and (4) resulting avoidance of major costochondral stair-step osteotomies. The suggested age of repair is 1 to 4 weeks of age.

Differentiation of the anterior body wall and truncal epidermis and associated co‐migration of cutaneous nerves and mesenchyme

The present study examines the relationship between the migration of mesenchyme and associated cutaneous nerves that are involved in the closure of the anterior body wall in embryonic mice and rats by light and electron microscopy. The sternum is formed by the migration of condensations of mesenchyme originating in the dorsolateral body wall known as sternal bands. In the course of analyzing this process in rodent embryos we have identified similar paired caudal extensions of the sternal bands that are responsible for the closure of the abdominal wall following resolution of the umbilical hernia, and we suggest these bands of mesoderm should be referred to as the abdominal bands. Both the sternal and abdominal bands are associated with the development of the segmental spinal nerves and their cutaneous terminal branches. The first cutaneous nerve to reach the skin surface in rats is the later cutaneous nerve (PCN and ACN) at E13.5 days. The ACN co-migrates with the sternal and abdominal bands, and terminal branches of axons from the ACN approach the epidermis during this migration. Differentiation of the epidermis could be recognized as a change in shape of epidermal cells from squamous to cuboidal, and this initial differentiation coincides with the onset of cutaneous innervation, beginning at the site of the LCN and following the extent of innervation of the PCN as well as the migration of the mesodermal bands and associated ACN. The paired ACN's meet in the ventral midline at E16.5 in rats as the sternal bands fuse, and terminal axons from both nerves densely innervate the midline skin.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful surgical repair of congenital total cleft sternum with partial ectopia cordis.

Total bifid sternum with or without ectopia cordis is a rare congenital anomaly which is treated successfully in a limited number of cases. Several methods of correction have been described using tissue grafts (cartilage, bone), inert artificial prostheses (acrylic plaques, marlex mesh), and techniques to approximate the sternal bands by relaxation of costal cartilages. In our case the method described by Verska was used to approximate the bifid sternal bands. The successful result in our patient proves the efficiency of this technique.

Parthenogenesis in a Beetle

I DO not know whether any instances have been recorded of parthenogenesis in the coleoptera, nor does the interest of the case I am about to relate consist in the discovery of the operation of a not uncommon mode of insect reproduction in a new field, but rather in its altogether abnormal and fortuitous character in the species of beetle concerned, viz., Gastrophysa raphani. My own observations hitherto on this species have been uniformly to the effect that unimpregnated females lay always barren eggs, and that one intercourse with the male renders fruitful all eggs subsequently laid. I bred the female in question from the egg this year, and have kept her isolated since her exclusion as an imago. She has laid, up to the present, about twenty batches of eggs consisting of about thirty-four and fifty-one alternately in the batch. Of these, some fifteen batches have been observed; and only in one of these, No. 10, to wit, consisting of thirty-four eggs, and in one of these thirty-four only were any traces of development observed. This batch was laid between the 2nd and 4th of August. On the 5th I noticed in one an appearance which is usual about this time in fertilised egg, which I have been accustomed to think about as the “embryonic scroll,” and which, on reference to Huxley's “Anatomy of In-vertebrated Animals,” pp. 444–445, I am inclined to think may be what is there called “the sternal band (Keimstreif of the German embryologists).“This scroll is invariably present in gastrophysa eggs regularly developing, and enables one to predict with certainty the position of the ventral aspect, and of the head and tail of the future larva. On the 6th this same appearance was more distinctly marked. On August 10 a further well-defined stage of development had been reached. On the 11th the ocelli were plainly visible. Next day I noted the antennae, mandibles, palpi, and legs. The segments, warts, and spiracles were also to be seen. On the 12th and some subsequent days I saw plainly somewhat feeble but unmistakable and decided movements of the legs, especially of the tarsi and ungues. At this season of the year the egg should have been hatched in about ten or twelve days. I have no longer any hope of this, and all larval movements appear to have ceased. All the other (thirty-three) eggs have undergone the usual degeneration, but this one presents a striking contrast to them, showing all the external parts perfectly formed and distinctly visible, as far as the position of the larva (which is just the reverse of the usual one, namely, with the dorsum in place of the venter next the surface of attachment) allows them to be seen. There is an un-unsual appearance of brownish coloration towards the caudal end, the nature of which I have not made out. The failure to hatch out, however, does not hinder this from being a decided case of embryonal development in an egg laid by a female of Gastrophysa raphani whose virginity is assured; and it is a solitary instance occurring among some eight or nine hundred eggs laid by the same beetle both before and after and along with it, all of which (as far as observed) were normally and uniformly barren.