Biomechanical stability of a supra-acetabular pedicle screw Internal Fixation device (INFIX) vs External Fixation and plates for vertically unstable pelvic fractures

Vigdorchik, Jonathan M.; Esquivel, Amanda O.; Jin, Xin; Yang, King H.; Onwudiwe, Ndidi A; Vaidya, Rahul

doi:10.1186/1749-799x-7-31

Cited by 93 publications

(80 citation statements)

References 22 publications

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“…In addition, there is no standard in biomechanical testing of pelvic ring fractures. The setup and some of the loads applied in this study were chosen similar to those reported in published studies [24,33,39,43]. In addition, a stepwise increase in loads [12,40] was chosen to simulate the cyclic loading environment resulting from different levels of weightbearing (toe-touch, walking with a walker, full weightbearing) because they would be expected in the heterogeneous elderly population with fragility fractures of the pelvis with very different levels of balance, compliance, and pain.…”

Section: Discussionmentioning

confidence: 99%

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

Osterhoff

Dodd

Unno

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Sacroiliac screw fixation in elderly patients with pelvic fractures is prone to failure owing to impaired bone quality. Cement augmentation has been proposed as a possible solution, because in other anatomic areas this has been shown to reduce screw loosening. However, to our knowledge, this has not been evaluated for sacroiliac screws. Questions/purposes We investigated the potential biomechanical benefit of cement augmentation of sacroiliac screw fixation in a cadaver model of osteoporotic bone, specifically with respect to screw loosening, construct survival, and fracture-site motion. Methods Standardized complete sacral ala fractures with intact posterior ligaments in combination with ipsilateral upper and lower pubic rami fractures were created in osteoporotic cadaver pelves and stabilized by three fixation techniques: sacroiliac (n = 5) with sacroiliac screws in S1 and S2, cemented (n = 5) with addition of cement augmentation, and transsacral (n = 5) with a single transsacral screw in S1. A cyclic loading protocol was applied with torque (1.5 Nm) and increasing axial force (250-750 N). Screw loosening, construct survival, and sacral fracture-site motion were measured by optoelectric motion tracking. A sample-size calculation revealed five samples per group to be required to achieve a power of 0.80 to detect 50% reduction in screw loosening. Results Screw motion in relation to the sacrum during loading with 250 N/1.5 Nm was not different among the three groups (sacroiliac: 1.2 mm, range, 0.6-1.9; cemented: 0.7 mm, range, 0.5-1.3; transsacral: 1.1 mm, range, 0.6-2.3) (p = 0.940). Screw subsidence was less in the cemented group (3.0 mm, range, 1.2-3.7) compared with the sacroiliac (5.7 mm, range, 4.7-10

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Section: Discussionmentioning

confidence: 99%

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

Osterhoff

Dodd

Unno

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…A second procedure is required for the removal of the implant at a minimum of 3-month time frame, which is most commonly described in the literature [5, 8]. Biomechanical studies have shown that the minimally invasive INFIX has superior stability to external fixation, due to the shorter lever arm of the construct [9]. However, compared with internal fixation, it has less stability and stiffness [9].…”

Section: Introductionmentioning

confidence: 99%

“…Biomechanical studies have shown that the minimally invasive INFIX has superior stability to external fixation, due to the shorter lever arm of the construct [9]. However, compared with internal fixation, it has less stability and stiffness [9]. …”

Section: Introductionmentioning

confidence: 99%

“…However, the classification of pelvic fractures is unreliable, even amongst pelvic surgeons, with low inter-examiner reliability [11], making the challenge of defining and reporting suitable fracture types vexed. The failure of the INFIX in the management of a morbidly obese patient with pubic diastasis [12] would suggest a limitation of the technique with open-book pelvic fractures which would be better managed with a stiffer and more stable internal fixation construct [9]. We report a single-centre prospective case series of the outcomes and complications associated with the INFIX technique.…”

Section: Introductionmentioning

confidence: 99%

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A prospective case series for a minimally invasive internal fixation device for anterior pelvic ring fractures

et al. 2016

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BackgroundExternal fixation is commonly used as a means of definitive fixation of pelvic fractures. Pin site infection is common, with some cases of osteomyelitis and inpatient nursing can be challenging. The aim of this study is to report the outcomes and complications of an alternative minimally invasive technique, known as INFIX, utilising spinal pedicle screws inserted into the supra-acetabular bone and connected by a subcutaneous rod.MethodsA single-centre prospective case series was performed. The primary outcome measures were fracture stability and displacement at time of implant removal and intra- and post-operative complications.ResultsTwenty-one patients were recruited, with 85.7 % of fractures being lateral compression type. Mean follow-up was 342 days. Mean application time was 51 min (range 44–65). Nineteen were removed electively, with mean time to removal 109 days. All cases were stable with no displacement. Two cases were removed emergently, one due to wound infection and the other due to lateral femoral cutaneous nerve neuropathic pain. Twelve patients sustained a lateral femoral cutaneous nerve palsy, with 20/42 nerves being affected. Improvement in all lateral femoral cutaneous nerve symptoms were reported with removal. Nine patients developed asymptomatic heterotopic ossification, and there were three deep infections and one symptomatic due to the bar.ConclusionsMinimally invasive internal fixation with the INFIX for anterior pelvic ring fractures is an alternative to anterior external fixation. However, a higher rate of lateral femoral cutaneous nerve palsy is noted, and the implant is not well tolerated by all patients. Further studies are required to define fracture types and patients best suited to the technique and how LFCN complications may be minimised.Trial registration ACTRN12616001421426. Registered 12 October 2016. Retrospectively registered.

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“…This method would also be an option where further abdominal surgeries are expected avoiding a potentially unstable "RHOMBOID" configuration. There is some evidence that such a device would be at least as stable as an external fixator [27].…”

Section: Discussionmentioning

confidence: 99%

Biomechanical Comparison of Different External Fixation Configurations for Posttraumatic Pelvic Ring Instability

Tiziani¹,

Osterhoff²,

Ferguson

et al. 2014

Advances in Orthopedic Surgery

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Background. External fixation is useful in the primary treatment of pelvic ring injuries. The present study compared the biomechanical stability of five different configurations of an external pelvic ring fixation system. Methods. Five configurations of an anterior external pelvic ring fixation system were tested using a universal testing machine. One single connecting rod was used in group “SINGLE,” two parallel connecting rods in group “DOUBLE,” two and four rods, respectively, in a tent-like configuration in groups “SINGLE TENT” and “DOUBLE TENT,” and a rhomboid-like configuration in group “RHOMBOID.” Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz lateral compression/distraction (±50 N) and torque (±0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700, and 900 cycles. Results. The “SINGLE TENT” and “RHOMBOID” configurations already failed with a preloading of 50 N compression force. The “DOUBLE” configuration had around twice the translational stability compared with the “SINGLE” and “DOUBLE TENT” configurations. Rotational stiffness observed for the “DOUBLE” and “DOUBLE TENT” configurations was about 50% higher compared to the SINGLE configuration. Conclusion. Using two parallel connecting rods provides the highest translational and rotational stability.

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Biomechanical stability of a supra-acetabular pedicle screw Internal Fixation device (INFIX) vs External Fixation and plates for vertically unstable pelvic fractures

Cited by 93 publications

References 22 publications

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

A prospective case series for a minimally invasive internal fixation device for anterior pelvic ring fractures

Biomechanical Comparison of Different External Fixation Configurations for Posttraumatic Pelvic Ring Instability

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