Sternal cleft is a rare congenital malformation, in which movements were evident, with anterior mediastinal viscera
the 2 sternal bars fail to fuse on the midline. The mostcommon form is the upper sternal cleft. Although theincidence is unknown, total clefts are very rare and mayrepresent a surgical challenge. Since the first correctionreported by Burton [1], many different techniques have beenproposed [2-5]. Primary closure of the 2 sternal bars on themidline is almost always achievable during the infancy, but itcan bring the risk of a circulatory impairment because ofcardiovascular compression. We describe a case in which weperformed a partial thymectomy to reduce this risk.
1. Case report
A 4-month-old male was admitted at our institute for amass in the upper anterior chest. Paradoxical respiratory
⁎ Corresponding author. Pediatric Surgery, G. Gaslini Institute, Largo G.aslini, 5, 16148, Genova, Italy. Tel.: +390105636217; Fax: +390103075092.E-mail address: [email protected] (M. Torre).
bulging through a complete sternal defect during expira-tion or crying but going deep into the mediastinum duringinspiration (Fig. 1). Cardiac pulsations were visible within
Fig. 1 Paradoxical respiratory movements during inspiration.
Fig. 2 Computerized tomographic scan showing a completesternal cleft.
Fig. 4 Identification of the 2 sternal bars, completely separatedone from the other, closer on the xyphoid extremity.
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the bulging viscera. The sternal cleft was complete andextended to the entire xyphoid, as confirmed also bycomputerized tomography (Fig. 2). The gap between the2 sternal bars measured up to 3 cm in the upper part. Thechild presented a supraumbilical raphé (type AB accordingto Lieber classification) [6], a skin tag on the defect, andan inferior labial hemangioma (Fig. 3). No aortic/cardiacmalformations were detected at echocardiography. Cranialultrasound and computerized tomographic scan ruled outintracranial abnormalities. Laryngoscopy demonstrated asmall laryngeal hemangioma. No other malformationswere observed.
The surgical correction of the sternum was realized afterthe preoperative workup was completed. A midline anteriorthoracic incision was performed, including the cutaneoustag. The skin flaps were raised, dissecting them from
Fig. 3 Hemangioma of the lower lip, cutaneous tag on thesternal cleft, and supraumbilical raphé. This type of abnormalitybelongs, associated with the sternal cleft, to the sternal malforma-tion/vascular dysplasia syndrome, often overlapped with thePHACE syndrome. Fig. 5 Isolation and excision of the right lobe of the thymus.
Fig. 6 Complete suture of the sternum, after excision.
E19Thymectomy to achieve primary closure of total sternal cleft
pericardium, pleura, and thymus. The 2 cartilaginous sternalbars were identified and dissected (Fig. 4). The lungs werevisible medial to them, through a very thin pleural plane. Onthe superior and inferior aspect of the dissection, themuscular structures (strap and rectus muscles) wereidentified and left untouched.
The margins of the 2 sternal bars were exposed andclosed directly with nonabsorbable interrupted stitches,starting from xyphoid, where they were closer, andproceeding in a cranial direction under strict surveillanceby the anesthesiologist. While closing the midsternum, thethymus started to bulge from the mediastinum, occupyingthe presternal space, and making the closure of the upperpart of the defect more difficult. After a partial thymectomy(the right lobe was excised completely, as shown in Fig. 5),we were able to close the entire sternum without anydifficulty (Fig. 6). A Penrose drain was left in thepresternal space.
The child did not present any circulatory or respiratorydistress. The tracheal tube could be removed withoutrespiratory problems in the immediate postoperative time.The drain was removed in the third postoperative day, andthe child was discharged 10 days after surgery. The laryngealhemangioma has not required any treatment up to now. Thebaby is healthy at 5 months follow-up.
2. Discussion
Sternal clefts are rare congenital malformations in whichthe sternal bars fail to fuse on the midline. They can beclassified in complete or incomplete [7], and the latter in
upper or inferior ones. As our case shows, these anomaliesmay belong to the sternal malformation/vascular dysplasiasyndrome, sometimes overlapped with the PHACE syn-drome (posterior fossa brain abnormalities, hemangiomas,arterial anomalies in the cranial vasculature, coarctation ofthe aorta/cardiac defects and eye abnormalities), which canbe incomplete [8,9]. Sometimes sternal cleft is associatedwith a supraumbilical raphé, which Leiber classifies into3 different types [6] as follows: type A, with sternal defect;type B, with hemangiomatosis but without sternal defect;and type AB, with sternal defect and hemangiomatosis.Sternal cleft are more common in females than in males andthe latter seem to have less related anomalies and a betterprognosis [10].
The 2 sternal bars, partially or totally unfused, leavemediastinal viscera covered only by the skin, with analternate protruding and retracting movement upon respira-tion. The surgical correction is always indicated to reduce therisk of external trauma. However, the surgical repair of theseanomalies can represent a serious challenge for the surgeon,especially if they are not treated during the neonatal period[11-15]. If the treatment is postponed after the first year ofage, the progressive ossification of the thorax can makeprimary closure impossible. Moreover, one of the risks thesurgeon has to consider when attempting primary closure isthe increasing compression on cardiac and vascular med-iastinal structures [14]. To reduce this risk and achieve asuccessful closure in difficult cases, different techniqueshave been described such as sliding chondrotomies [2], orthe creation of a posterior sternal wall with periosteal flaps[14]. Another option is represented by the closure withprosthetic or autologous materials [14-17]. However, thissolution is less attractive—apart from the risk of infection
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when prosthetic material is used, the closure of the defectwith exogenous or autologous materials it is not alwaysstable, and recurrence rate is higher [5]. Moreover, depend-ing on the type of prosthesis used, other surgical proceduresare often required to remove or replace it.
In our case, the cleft involved the entire sternum withthe xyphoid, and the gap between the 2 bars was verywide. These features are uncommon; in the largest series ofsternal cleft, described by Acastello [5], none had completecleft, and only few cases are reported in the literature[11,14]. Although in our patient primary closure could beat risk, it was attempted because of its advantage over theprosthetic closure. Even if preoperative workup did notreveal any enlargement of the thymus, during theoperation, the bulging gland seemed to interfere with asafe closure. A partial thymectomy was an effectivemaneuver to reduce the mediastinal pressure and allowedus to close the upper part of the defect, where the gapseemed too wide.
We suggest considering this simple maneuver as a usefulsurgical trick in selected cases. In our opinion, primaryclosure of sternal clefts should be always attempted, understrict surveillance by the anesthesiologist, and othertechniques of repair should be reserved to those cases inwhich primary closure is shown impossible or unsafe forthe patient.
In conclusion, partial thymectomy could allow primaryclosure in those selected cases in which the gland bulgingseems to prevent approximation of both sternal bars.
Acknowledgment
Thanks to Francesca Roncallo for helping in collectingclinical data.
References
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