Can a Modified Anterior External Fixator Provide Posterior Compression of AP Compression Type III Pelvic Injuries?

Abstract

Background Current anterior fixators can close a disrupted anterior pelvic ring. However, these anterior constructs cannot create posterior compressive forces across the sacroiliac joint. We explored whether a modified fixator could create such forces. Questions/purposes We determined whether (1) an anterior external fixator with a second anterior articulation (X-frame) would provide posterior pelvic compression and (2) full pin insertion would deliver higher posterior compressive forces than half pin insertion. Methods We simulated AP compression Type III instability with plastic pelvis models and tested the following conditions: (1) single-pin supraacetabular external fixator (SAEF) using half pin insertion (60 mm); (2) SAEF using full pin insertion (120 mm); (3) modified fixator with X-frame using half pin insertion; (4) modified fixator using full pin insertion; and (5) C-clamp. Standardized fracture compression in the anterior and posterior compartment was performed as in previous studies by Gardner. A forcesensitive sensor was placed in the symphysis and posterior pelvic ring before fracture reduction and the fractures were reduced. The symphyseal and sacroiliac compression loads of each application were measured. Results The SAEF exerted mean compressions of 13 N and 14 N to the posterior pelvic ring using half and full pin insertions, respectively. The modified fixator had mean posterior compressions of 174 N and 222 N with half and full pin insertions, respectively. C-clamp application exerted a mean posterior load of 407 N. Conclusions Posterior compression on the pelvis was improved using an X-frame as an anterior fixation device in a synthetic pelvic fracture model. Clinical Relevance This additive device may improve the initial anterior and posterior stability in the acute management of unstable and life-threatening pelvic ring injuries.

A Method of Using a Pelvic C-Clamp for Intraoperative Reduction of a Zone 3 Sacral Fracture

“…In biomechanical studies, C-clamps have been shown to apply some of the highest compressive loads on the posterior pelvic ring [14]. Figures 4(a), 4(b), and 4(c) demonstrate the healed pelvis with multiple broken screws two years postoperatively.…”

Resuscitation of Polytrauma Patients: The Management of Massive Skeletal Bleeding

“…Anterior external fixation frames provide poor stabilisation for posterior pelvis ring lesions, and therefore posterior fixation is advisable [ 41 ]; this can be provided either by a C-clamp device [ 42 , 43 ] or by iliosacral screwing [ 44 - 47 ]. These and other techniques have been widely applied, and the results published by many authors (Figs.…”

“…Since prompt C-clamp application in a patient who is bleeding be troublesome and can also provoke severe iatrogenic complications [ 51 ], many attempts have been made to construct an anterior frame for posterior compression, seeking to close the sacroiliac complex in an efficient manner [ 41 ]. However, reproducing research findings in practical situations is still a problematic issue [ 52 ].…”

Orthopedic Approach to the Early Management of Pelvic Injuries

“…While the external fixation of the iliac wings is excellent at controlling the anterior pelvic ring and managing fracture patterns that involve primarily anterior displacement or "open book"-type injuries, injuries that involve the significant displacement of the posterior pelvic ring are often poorly controlled with external fixation alone [43,44]. External fixator pins are placed into the anterior ring, and given the long lever arm between the posterior ring and the anterior frame, there is little ability to directly control the posterior pelvic ring.…”