Intramedullary reinforcement of sternal fixation with autologous xiphoid tenon

Introduction

Minimally invasive or less invasive cardiac surgery through a partial sternotomy or a ministernotomy was advocated for the cosmetic, respiratory, transfusion, and pain advantages over the conventional surgery (1,2). However, it exposes a patient to the potential risk of transverse sternal nonunion (3). Valid and valuable techniques and materials have been developed for securing the sternotomy fixation (3-6). Most of them are focused on the materials or methods for the extrinsic reinforcement. Instead, we have designed an intrinsic reinforcement method for sternal fixation by intramedullary incarceration of a cancellous portion of the autologous xiphoid in the inter-segmental junction of the partial sternotomy.

Technical note

The entire xiphoid was harvested during the lower-half partial sternotomy. The attached cartilage portion, soft tissue, and the periosteum were removed from this autologous bone graft. At the end of the cardiac operation, the transverse sternotomy was loosely wired as figure-of-8 fashion and the vertical sternotomy was wired as usual. Before approximation, the interfacial marrow of the transverse sternotomy site was enucleated with curette and the prepared xiphoid was embedded in the bone marrow space, hence this bone graft was incarcerated as an intramedullary tenon in the inter-segmental space of the partial sternotomy site snugly (Figure 1). Additional fixation for the bone graft was not needed. The wires were approximated thereafter (Figure 2).

Figure 1 An intraoperative photo demonstrated an incarcerated xiphoid tenon (X) in the marrow space of the inter-segmental junction of the partial sternotomy before approximation.

Figure 2 An illustration demonstrating fixation of the partial sternotomy with the xiphoid tenon technique.

This adjunctive technique was applied in 107 patients who received a full-spectrum cardiac surgery through the lower-half partial sternotomy from January 2011 to December 2013 (Table 1). There were three patients (2.8%) suffered from mild pseudoarthrosis of the transverse sternotomy site without any adverse sequela. There was no patient requiring second operation for the sternal fixation for dehiscence. In contrast, there were 747 patients who received a full-spectrum cardiac surgery through the lower-half partial sternotomy between January 2000 and December 2010 without this adjunctive technique. The pseudoarthrosis of the transverse sternotomy site was noted in 36 patients (4.8%). No one in these two cohorts of 854 patients experienced any lower vertical sternotomy site dehiscence.

Table 1 Demographic data of the 107 patients
Full table

Discussion

Minimally invasive or less invasive cardiac surgery through a partial sternotomy or a ministernotomy was advocated for the cosmetic, respiratory, transfusion, and pain advantages (1,2). This approach is popular in current era. Various types of partial sternotomy have been reported such as lower-half sternotomy (1), J incision, and partial right lower sternotomy (2). Because elasticity and movement of the chest wall during respiration will compromise the rigid sternal fixation, sternal nonunion or dehiscence is a well-known complication encountered in patients after sternotomy. The sternal dehiscence rate was reported to be 18 (1.4%) of 1,268 patients after cardiac surgery (7). Although vertical sternal nonunion has been seldom reported, transverse nonunion may be more commonly associated with the partial sternotomy due to the fragmented sternal interface created by this method (3). Valid and valuable techniques and materials have been developed for securing the sternotomy fixation including modifications of sternal wiring method or invention of new sternal fixation device (3-6). Most of them are focused on the materials or methods for the extrinsic reinforcement.

The superiority of intramedullary fixation in stiffness and resistance to the bending moments is a well studied issue in the plastic and orthopaedic field (8). A xiphoid process composed of cartilage and cancellous bone, exposed during a sternotomy is an on hand bone graft. Excision of this in situ structure for autologous bone grafting showed nothing detrimental and another incision for the iliac bone grafting could be spared. By using the cancellous portion of the xiphoid process as an intramedullary tenon, we successfully reinforced the transverse sternotomy site of the partial sternotomy and reduced the nonunion rate from 4.8% to 2.8%. Although statistically not significant, we believe that the reduced odd ratio of 1.76 by this technique will be an attractive merit without any drawback.

The use of autologous bone graft is not a new idea. Autologous iliac bone transplant after sternal resection had been reported by Piotrowski and his colleagues, however this graft required another incision and not available for intramedullary reinforcement (9).

There are some limitations in this autologous xiphoid tenon method. As a bone graft, only the cancellous portion of the xiphoid is on demand. Therefore, in some younger patients without ossified xiphoid, this method is not suitable for use. Moreover, this method is not suitable for the incisions sparing the xiphoid area such as J incision. Since we report on a technical evolution and refinement, the nature of sequential population enrollment without randomization is the inevitable limitation of this study.

Acknowledgements

None.

Footnote

Conflicts of Interest: The author has no conflicts of interest to declare.

References

1. Doty DB, DiRusso GB, Doty JR. Full-spectrum cardiac surgery through a minimal incision: Mini-sternotomy (lower half) technique. Ann Thorac Surg 1998;65:573-7. [Crossref] [PubMed]
2. Svensson LG, Atik FA, Cosgrove DM, et al. Minimally invasive versus conventional mitral valve surgery: A propensity-matched comparison. J Thorac Cardiovasc Surg 2010;139:926-32.e1-2. [Crossref] [PubMed]
3. Bertin KC, Rice RS, Doty DB, et al. Repair of transverse sternal nonunions using metal plates and autogenous bone graft. Ann Thorac Surg 2002;73:1661-2. [Crossref] [PubMed]
4. Robicsek F, Daugherty HK, Cook JW. The prevention and treatment of sternum separation following open-heart surgery. J Thorac Cardiovasc Surg 1977;73:267-8. [PubMed]
5. Murray KD, Pasque MK. Routine sternal closure using six overlapping figure-of-8 wires. Ann Thorac Surg 1997;64:1852-4. [Crossref] [PubMed]
6. Ooi A, Franklin D, Ohri S. Improved technique of nitinol sternal clip application. Ann Thorac Surg 2009;87:1971-2. [Crossref] [PubMed]
7. Redžek A, Mironicki M, Gvozdenović A, et al. Predictors for hospital readmission after cardiac surgery. J Card Surg 2015;30:1-6. [Crossref] [PubMed]
8. Capo JT, Melamed E, Shamian B, et al. Biomechanical evaluation of 5 fixation devices for proximal interphalangeal joint arthrodesis. J Hand Surg Am 2014;39:1971-7. [Crossref] [PubMed]
9. Piotrowski JA, Fischer M, Klaes W, et al. Autologous bone transplant after sternal resection. J Cardiovasc Surg (Torino) 1996;37:179-81. [PubMed]