Artikel
Transoral reconstruction of C2 with a custom-made titanium prosthesis
Transorale Rekonstruktion von HWK 2 mit einer vorgefertigten Spezialprothese
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
Text
Objective
Destructive disease of the craniocervical junction may be treated by either posterior instrumentation and fusion or anterior transoral decompression. Until now, there has been no custom-made device for an anatomical reconstruction of the C2 that guarantees for immediate axial stability following complete anterior removal of the dens as well as the corpus of C2.
Methods
After transoral removal of the dens together with the corpus of C2 there is a 12-15mm gap in the anterior ring of C1. The axial support of the lateral mass of C1 by the C2-joints is also missing on both sides. All ligaments between C1 and C2 have been removed. There is a complete bony and soft tissue disruption that requires a sophisticated prosthetic device for reconstruction and stabilization. A titanium mesh device was designed that combines the well-known reconstructive properties of a tube-like mesh cage (Harms cage) with the advantages of an anterior plate for screw fixation (Jeszenszky et al, Europ Spine J 1999(8), Suppl 1, P38). The new titanium mesh prosthesis has a “double-F”-shape in the ap view. The top bar is an anterior plate that is fixed to both sides of the open C1 ring in its lateral masses. In the middle is an oval shaped mesh ring that supports both sides of the open C1 ring in resemblance to the C2 joints that have been removed. The vertical trunk of the prosthesis rests on C3. This is the recognized circular mesh cage that replaces the lower part of the dens and the corpus of C2. There is a caudal anterior plate like end that allows for screw fixation in C3. The prosthesis is always combined with a primary posterior C1-C3-instrumentation.
Results
The new prosthesis for transoral reconstruction of C2 was used in metastatic disease, in infectious disease and in degenerative destruction of C2 with major deformity. We present 4 of 12 cases operated worldwide by three surgeons. Prosthetic reconstruction allowed for complete realignment with physiologic profiling of the craniocervical junction. No intraoperative complications and no screw loosening or implant failure have been observed.
Conclusions
The new C2-prosthesis allows for removal and reconstruction of extensive destructive lesions of the axis and it assures stable fixation thereafter. Posterior instrumentation combined with transoral reconstruction is a challenging procedure. If restricted to patients with singular metastasis and no comorbidity or monofocal lesions of other etiology, excellent functional results can be achieved.