TREATMENT OF ODONTOID PROCESS FRACTURES by anterior screwing ACCORDING TO BÖHLER’S TECHNIQUE.

 

I. IOB, C. BATTAGGIA, E . BAVARESCO, G. ZAMBON

The Authors present a retrospective analysis of 39 patients operated of anterior fixation for odontoid process fractures during the last 14 years (1987-2001). There were 29 males and 10 females, mean age 54,4 years, all affected from type II traumatic fractures according to Anderson-D’Alonso classification.

In this type of fractures, particularly those with posterior downward obliquity, the conservative treatment (Halo cast or collar) may result inadequate, mostly for the risk of pseudoarthosis in elder patients.

For this reason many surgical  posterior approaches have been proposed, as C1-C2 wiring and/or authologous bone grafting, occipital C2 plating, or C1-C2 transarticular screwing.

Unfortunately, all these procedures induce the definitive loss of the main function of this segment, i.e. the axial rotation.

Although the remaining cervical units may contribute ,the loss of rotational capacity exceeds the 50%,which is unacceptable for subjects with a normal relational life. 

The advantage of the anterior screw fixation of the odontoid, according to the tecnique proposed by Böhler (G. Böhler, 1975), on the contrary, is an immediate and solid fracture stabilization and the preservation of the segmental motility.

Main surgical indications are:

a-      type II fractures with posterior downward obliquity (35 cases) or upward posteriorly directed (4 cases), the latter only if the fracture diasthasis exceeds 3 mm.

b-     patients over 40

c-      patients younger than 40 with head fracture controindicating an Halo-cast

The surgical approach to the anterior part of C2-C3 disk is made through an oblique pre-sterocleidomastoid muscle incision and exposure of the anterior longitudinal ligament at C4-C5.

The creation of a median tunnel along the anterior aspect of the spine, is made easier by a Landolt speader (commonly used for transphenoid surgery).Once identified the inferior aspect of C2 endplate, drilling of C2 and the odontoid process is followed by a single cortical screw insertion, generally of 35  to 45 mm (Fig. 1); in addition,  the recent introduction of titanium or polylactic acid screws        (used in 8 and 5 cases respectively) makes MRI examination possible.

The main technical problems were relatedto a short neck (19 cases) or a prominent chest ( 2 cases) , both solved with the use of angled drills of different lenghts.None of our patients required a double screw fixation (as in the original Böhler 's procedure), as no axial rotation of the dens during drilling occured.

Postoperative course was uneventful , except but transient laryngeal disturbancies in 6 cases during the first 48 hours.

And all the patients were discharged from hospital 3 to 12 days after surgery, with a soft collar for 3 weeks.There was no late complication (2 patients died for intercurrent pathologies).

In conclusion, in our experience, the anterior odontoid process fixation seems to be a safe and quick procedure which, in addition, mantains the original mobility of this delicate cervical spine segment.

 

 

Authors address:     

     Departement of Neurological Sciences, Neurosurgical Unit, Padova University  Via Giustiniani 5 35100 Padova (Italy) Tel: 00390498213661 Fax 0039049665421