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Percutaneous fixation ofpelvic andacetabular fractures

Rami Mosheiff

The application of percutaneous fixation techniques with pelvic

and acetabular fractures.

Unstable pelvic-ring injuries call for anatomical reconstruc-

tion and stable fixation to allow for early function. As the

surrounding anatomical vicinity contains vital vulnerable

structures, the percutaneous surgical approach becomes an

attractive treatment option minimizing exposure, blood loss,

risk of infection, and protecting vital structures. To safely

apply percutaneous reduction and fixation techniques, a thor-

ough understanding of the complex three-dimensional pelvic

anatomy and radiology is necessary. This knowledge is more

complex than that required for long bone fixation.

Indications Although percutaneous pelvic surgery is contro-

versial [1], this approach has gained popularity due to the fol-

lowing:

A pelvic-ring fracture is not an intraarticular fracture re-

quiring a perfect reduction so a near anatomical recon-

struction is accepted without significantly affecting the

clinical outcome.

The percutaneous approach complements the more open

traditional method by minimizing the open approach in

certain areas where it can be safely implemented.

The percutaneous fixation of acetabular fractures has a com-

pletely different approach. This is a weight-bearing joint so

anatomical reconstruction is recommended and inaccuracy in

reduction and/or fixation will result in a compromised out-

come. In certain circumstances, it is acceptable to achieve sec-

ondary congruency while avoiding the use of extensile and

unsafe exposures. Additionally, some of the screw pathways,

routinely used in percutaneous pelvic surgery, can be used

in acetabular fracture fixation. The learning curve achieved

during pelvic surgery procedures can be utilized for more de-

manding acetabular surgery.

Implementation Implementation of percutaneous pelvic

and acetabular fracture surgery occurs in three stages: un-

derstanding the fracture and preoperative planning; indirect

reduction techniques; and percutaneous fixation.

Preoperative planning Although 3-D CT has considerably

improved the understanding of fracture patterns it has not

yet allowed the percutaneous placement of plates or improved

reduction techniques. Currently, the control of screw orienta-

tion is possible only with fluoroscopy so strict pre-operative

planning is mandatory in percutaneous pelvic and acetabular

surgical treatment to avoid complications. Recently, computer

programs have been developed enabling the performance of

virtually all steps of the real surgical procedure including de-

termination of the safe zones for fixation, precise planning of

screw dimensions, and pre-checking of the percutaneous op-

tion as an alternative to open approach (Figs 14) [23].

Reduction A precise closed reduction is a prerequisite for

percutaneous pelvic fixation and even more so for acetabular

fractures. As a consequence, there are three indications for

percutaneous pelvic fixation: minimally displaced pelvic or

acetabular fractures, displaced fractures with a feasible closed

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Fig 1ab A computerized preoperative planning device (SQ Pelvissoftware) enables complete virtual operation on the model acquiredfrom real patient data (CT). Using 3-D viewing tools, the virtual modelof a fractured acetabulum is built. Following reduction, fixation canbe undertaken. The direction and length of the screws is controlled byturning the pelvis (a) or by making the bones more transparent (b).

Fig 2 Percutaneous screw insertion by means of computerizedfluoroscopic navigation system enables the simultaneous use ofseveral radiographic projections. This system has the potential tosignificantly reduce radiation exposure and operative time, whileallowing the surgeon to achieve maximum accuracy.

Fig 3 Three-dimensional fluoroscopy allows the acquisition of C T-likeimages during surgery by taking about 100 fluoroscopic x-ray images at1 intervals with a motorized isocentric C-arm. The navigation imagesconsist of both C T and fluoroscopic x-ray images. The advantagesbeing that complex fractures can be better visualized and that C Timages, prior to and following reduction, can be taken.

Fig 4 Immediate postoperative x-ray. Closed disruption of left side ofpelvic ring with vertical displacement through left sacroiliac joint. Thepatient was hemodynamically unstable on arrival.

1b1a

2

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reduction, and complex fractures in which a combination of

closed and open reduction is necessary. It is quite clear that

the development of closed reduction techniques is pertinent

for achieving a breakthrough in this field. Recently, innova-

tive tableskeletal pelvic fixation frames have been devised to

secure the normal side of the pelvis to the table so as to more

effectively apply the reduction maneuvers to the displaced

hemipelvis [4] (Figs 57).

Intraoperative control Intraoperative rather than postopera-

tive confirmation of the reduction and fixation can save pa-

tients and surgeons from uncertainty relating to the quality of

reduction and implant position. The introduction of operative

3-D imaging (SireMobil IsoC-3-D, Siemens Medical Solutions,

Erlangen, Germany), combines the capabilities of routine in-

traoperative fluoroscopy with resultant axial cuts, 2-D and

3-D reformations. This unique imaging modality can help the

surgeon assess the acetabulum and the posterior pelvic ring

anatomy intraoperatively [56]. The persisting disadvantage

of 3-D fluoroscopes is a limited image size, however newer

modifications will allow superior image quality, increased

field of view, higher spatial resolution, and soft-tissue visibil-

ity as well as the elimination of the need to rotate around a

fixed point (isocentricity).

Fixation Conventional fluoroscopy is used most frequently

in percutaneous pelvic fixation. However, it provides only a

two-dimensional image and requires multiple images in dif-

ferent projections to determine the correct point of entry and

trajectory of the screw resulting in prolonged exposure for the

patient and surgical team screw position error and the need

for a proficient and available radiology technician. The intro-

duction of computerized navigational systems may overcome

many of the previous objections to this technique [78]. Sev-

eral studies have already demonstrated higher precision, de-

creased radiation exposure and lower revision rates with the

use of navigation techniques for percutaneous screw fixation

around the pelvis and acetabulum (Fig 1).

Summary The goals in the treatment of pelvic and acetabu-

lar fractures are achieving anatomic reduction of articular le-

sions (sacroiliac joint, acetabulum) followed by stable fixation.

Only the experienced pelvic and acetabular surgeon has the

surgical judgment and experience to decide if it is possible to

achieve these goals with a percutaneous procedure. If the dif-

ficulties entailed in integrating the new technology despite

its initial cumbersomeness is accomplished then the advanced

preplanning capabilities, improved accuracy of implant place-

ment, significant reduction in radiation exposure, and cre-

ation of a powerful educational and quality control tool will

be available.

5b5a

Fig 5ab Preoperative x-ray (a) and CT image (b).



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Bibliography

1. Rommens PM (2007) Is there a role for percutaneous pelvic and

acetabular reconstruction? Injury; Apr;38(4):463477.2. Cimerman M, Kristan A (2007) Preoperative planning in pelvic and

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Injury;38(4):442449.

3. Attias N, Lindsey RW, Starr AJ, et al (2005) The use of a virtual

three-dimensional model to evaluate the intraosseous space available for

percutaneous screw fixation of acetabular fractures. J Bone Joint Surg Br;

87(11):15201523.

4. Matta JM, Yerasimides JG (2007) TableSkeletal Fixation as an adjunct

to pelvic ring reduction. J Orthop Trauma; 21(9):647656.

5. Atesok K, Finkelstein J, Khoury A, et al (2007) The use of

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intraarticular fractures. Injury; 38(10):11631169.

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7b

Rami Mosheiff

Hadassah University Medical Center

Jerusalem, Israel

[email protected]

Fig 6 After external fixation and arterial embolization.

Fig 7 The Starr frame assists with closed anatomical correction ofthe deformity. The device is based on tableskeletal pelvic fi xation:securing the normal side of the pelvis to the table and maneuveringthe other hemipelvis. After reduction, percutaneous sacro-illiac

fixation can easily be achieved (Courtesy of Adam J. Starr, MD).

expert zone clinical topic


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