Blind Zone Determination of the Femoral Head

Orr, Terrence R.; Bollinger, Bruce A.; Strecker, William B.

doi:10.1097/01202412-198909040-00007

Cited by 2 publications

(3 citation statements)

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“…In this procedure, the precise aiming of the cannulated screw in all planes in a deformed proximal femur remains technically challenging. The narrow safe zone available for the screw requires utmost precision to avoid deleterious complications [11,[14][15][16]. By using computerized navigation, the lateral view as well as they AP and additional oblique views are constantly available while the screw is being inserted.…”

Section: Discussionmentioning

confidence: 99%

Computerized Navigation for Treatment of Slipped Femoral Capital Epiphysis

Weil

Pearle

Liebergall

et al. 2006

HSS Journal®: The Musculoskeletal Journal of Hospital for Speci

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In situ pinning with a single screw is the treatment of choice for symptomatic slipped capital femoral epiphysis (SCFE). Some technical features are critical and include proper screw entry point, screw direction in relation to the epiphysis, and the length of screw. These are complicated by the deformity created as a result of the posterior slip of the epiphysis. Fluoroscopic based computerized navigation system can increase precision in screw placement while performing the surgical task, and markedly reduce radiation. By using real fluoroscopy-based navigation, the screw can be placed with only two fluoroscopic images. Entry point, length, and precise direction can all be easily determined through this technique.

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Section: Discussionmentioning

confidence: 99%

Computerized Navigation for Treatment of Slipped Femoral Capital Epiphysis

Weil

Pearle

Liebergall

et al. 2006

HSS Journal®: The Musculoskeletal Journal of Hospital for Speci

View full text Add to dashboard Cite

show abstract

“…Various methods have been proposed in the literature including mathematical models 13,14 and the approach-withdraw technique. 15 Many surgeons use the approach-withdraw technique in judging the STSB distance.…”

Section: Introductionmentioning

confidence: 99%

“…12 Intra-operative imaging plays an essential role in determining accurate screw placement in SCFE fixation. Various methods have been proposed in the literature including mathematical models 13,14 and the approach-withdraw technique. 15 Many surgeons use the approach-withdraw technique in judging the STSB distance.…”

Section: Introductionmentioning

confidence: 99%

Fluoroscopic imaging overestimates the screw tip to subchondral bone distance in a cadaveric model of slipped capital femoral epiphysis

Heffernan

Snyder

Zhou

et al. 2017

Journal of Children's Orthopaedics

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PurposeIntra-operative imaging plays a key role in screw placement for slipped capital femoral epiphysis (SCFE). Complications have been associated with inadequate screw position. The purpose of this study was to evaluate computed tomography (CT) (3D fluoroscopy) and standard fluoroscopy (C-arm) images as compared with direct anatomic measurement to determine final screw position in a cadaveric SCFE model.MethodsOsteotomy with pinning was performed at the physeal scar in ten cadaveric hips. A standardised approach-withdrawal technique was performed with C-arm images taken at 15° increments. We also obtained a CT (3D fluoroscopy) scan of each hip. The screw tip-subchondral bone (STSB) distance was measured on digital imaging software and also with a digital calliper directly when the femoral head was cut in plane to expose the STSB distance anatomically. Statistical analysis included t-tests and Fisher’s exact test.ResultsModerate SCFE osteotomies were achieved with a mean Southwick angle (39.5° ± 7°). The 60° fluoroscopic image was found to be the most representative image (41% of the time) compared with both anteroposterior (AP) and lateral images (8% and 21%). Both fluoroscopy (2.7 ± 0.8 mm, p < 0.001) and CT (1.6 ± 0.7 mm, p = 0.03) overestimated the STSB distance compared with direct measurement (0.94 ± 0.51 mm). Two-thirds (67%) of CT measurements were within 1 mm of the cadaveric measurement, while only 20% of C-arm measurements fulfilled this criterion (p = 0.04).ConclusionsBoth standard fluoroscopy and CT overestimated the STSB distance when compared with direct measurement in a cadaveric model of SCFE. Surgeons should be aware of the limitations of intra-operative imaging to determine the STSB distance. We suggest that using the known pitch of a screw (2.9 mm in a 7.3-mm cannulated screw) as an intra-operative tool to help guide screw placement.

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Blind Zone Determination of the Femoral Head

Cited by 2 publications

References 0 publications

Computerized Navigation for Treatment of Slipped Femoral Capital Epiphysis

Computerized Navigation for Treatment of Slipped Femoral Capital Epiphysis

Fluoroscopic imaging overestimates the screw tip to subchondral bone distance in a cadaveric model of slipped capital femoral epiphysis

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