Retrospective Assessment of Thirty-Two Cases of Pelvic Fractures Stabilized by External Fixation in Dogs and Classification Proposal

Abstract

The goals of this study were to evaluate the outcomes of bone healing, patient comfort during the treatment, functional results, and complications in pelvic fractures treated with external fixation, as well as to propose a classification system for the applied external frames. A total of thirty-two canine patients with pelvic fractures of different origins were treated. To provide a better reference for the frames used, an alphanumeric classification system was developed, detailing the frame structure and the number and location of the pins used. In this study, eighty-six fractures were treated in the 32 patients of this work, with an average fixation time of 9.88 ± 4.15 weeks. No major complications were detected in this case cohort, and the outcomes were rated at 9.46 based on a visual assessment scale for the patient's comfort during treatment. Outcomes graded as excellent and good were 96%. The use of external fixation for stabilization of pelvic fractures should be considered as a technical option, especially for minimally invasive stabilization of complex fractures, either as a primary or secondary stabilization.

Keywords: dog; external fixation; external fixation classification; fractures; pelvis.

Figure 1

Segments into which the pelvis can be divided according to the proposed nomenclature for pelvic external fixation systems.

Figure 2

Different types of interconnections between hemipelves used as external fixation in the present study, as well as a classification proposal. Type T: a single bar interconnects the pins located on both iliac wings. Type C: the bars connect the pins on the iliac wing and ischiatic tuberosity of one hemipelvis to each other, and with the pin located on the wing of the contralateral ilium. Type O: the bars interconnect the pins of each hemipelvis around the perimeter. Type L: the bars connect the pins of one hemipelvis to each other and with the pin located on the contralateral ischial tuberosity. Type X: the bars interconnect the pins around the perimeter and with a cross-connection between the pins located at the vertices of the quadrilateral.

Figure 3

Descriptive illustration of the example for the proposed classification for pelvic external fixators with a configuration “I2.II1.III1.X.I1.II0.III1”.

Figure 4

(Top left): Ventrodorsal (VD) projection of a patient with a fracture of the left ilium and a conminuted fracture of the contralateral acetabulum. (Top right): lateral projection of the same patient. (Bottom left): The fractures were reduced and stabilized by a type O radiolucent EF system. Note the plate used for the fracture of the ilium. (Bottom right): lateral projection of the same patient.

Figure 5

External appearance of the EF system used in the patient of Figure 4. A Polilock system composed of plastic and carbon fiber material was used.

Figure 6

(Top left): VD projection of a patient with left acetabulum, ischial and pubic fractures. Note the fracture of the left articular process of the sacrum. (Top right): Lateral projection of the same patient. (Bottom left): The fractures were stabilized by a type O radiolucent EF. The radiolucent components of the EF provide a better visualization of the bone. (Bottom right): PO lateral projection of the patient.

Figure 7

Picture of the type O EF used in the patient of Figure 6. Note the double connection bar between pins located in both ilial wings and ischia.

Figure 8

(Top left): VD view of a patient with fracture of the right ilium and of the right sacral articular process, and a left sacroiliac luxation. (Top right): Lateral projection of the same patient. (Bottom left): A combination of a type C EF and a plate have been used to stabilize the fractures. Note the lag screw for the left sacroiliac luxation. (Bottom right): Lateral projection of the same patient.

Figure 9

(Left): Radiograph of a patient treated with a type X EF. Note the fracture located on the ischial branch of both hemipelves and the pins inserted into the 7th lumbar vertebra to stabilize an additional fracture of the right sacral articular process. (Right): Picture of the external appearance of the EF.