Computer manufactured Patient-specific Auto-reducible plate versus standard Trapezoid plate in Unilateral Subcondylar fractures

Purpose: Subcondylar fractures account for a high incidence of mandibular fractures
representing a frustrating clinical dysfunction and serious complications when maltreated. This
study aimed to compare the computer designed and manufactured patient-specific auto-reducible
plate to the standard trapezoid plate in attempt to reach the optimal geometrical design for
subcondylar fracture plate fixation.
Patients and methods: A total of sixteen patients suffering from unilateral subcondylar fracture
were included in this study from the outpatient clinic of the department of oral and maxillofacial
surgery, faculty of Dentistry, Cairo University. All patients were subjected to preoperative clinical
evaluation and 3-D CT examination to assess the degree of fracture displacement and condylar
location. The selected patients were divided into two groups, eight patients each. In group A patients,
virtual fracture reduction through mirroring of the unaffected intact side was performed, which was
then used as a template for designing and processing of the titanium patient-specific condylar plate
via direct metal laser sintering. While in group B patients, the unilateral sub-condylar fractures were
manually reduced into position and fixed in place by the standard trapezoidal mini-plate. Fixation
of the plates in both groups was then performed using 2.0 mini-screws. Postoperative clinical
assessment of the occlusion, Maximum inter-incisal opening (MIO) and mandibular deviation was
done at one week, 1 month & 3 months. Immediate postoperative radiographic assessment was
performed through the superimposition of the postoperative CT data of the fixed fracture on the
preoperative virtually reduced mandibular model as a reference CT data to validate and compare
the accuracy of the achieved postoperative fixation in both groups.
Results: The surgeries in all cases proceeded without any complications. Surgical site
examination was normal with no signs of infection. The occlusion was satisfactory at the end of the
study interval despite the initial slight immediate postoperative occlusal discrepancy found in both
groups. Deviation was not completely absent in both groups at the end of the follow-up period. The
MIO ranged from 39-47 mm at the end of the study with no significant difference between both
groups. The CT scan revealed the almost precise adaptation of both plates in place with no significant
difference, however, with the advantageous fracture auto-reduction, intra-operative time saving and
ease of application recorded with the use of the PS-condylar plate in group A patients. The mean
operating time for reduction and fixation using the PS-condylar plate was 90 minutes compared
to a mean of 88 minutes using the standard reduction and trapezoid plate fixation technique.
Conclusion: Despite of the approaching accuracy of both plates, preoperative digital virtual
planning and PS-plate processing were highly beneficial in the auto-reduction of the fractured
segments. The intra-operative time saving and ease of application with less obtained surgical errors
due to the planned surgery and the perfect fit of the prosthesis were found very valuable. Therefore,
accommodating with the continuous technological updates, the integration of computer programs
in surgery planning and plate designing and manufacturing in subcondylar fractures is highly
desirable due to its great benefits.