Complications of Anterior Subcutaneous Internal Fixation for Unstable Pelvis Fractures: A Multicenter Study

Detroit Medical Center, Wayne State University, 4D-4 University Health Center, Detroit Receiving Hospital, Detroit, MI 48201, USA.
Clinical Orthopaedics and Related Research (Impact Factor: 2.77). 01/2012; 470(8):2124-31. DOI: 10.1007/s11999-011-2233-z
Source: PubMed


Stabilization after a pelvic fracture can be accomplished with an anterior external fixator. These devices are uncomfortable for patients and are at risk for infection and loosening, especially in obese patients. As an alternative, we recently developed an anterior subcutaneous pelvic internal fixation technique (ASPIF).
We asked if the ASPIF (1) allows for definitive anterior pelvic stabilization of unstable pelvic injuries; (2) is well tolerated by patients for mobility and comfort; and (3) has an acceptable complication rate.
We retrospectively reviewed 91 patients who incurred an unstable pelvic injury treated with an anterior internal fixator and posterior fixation at four Level I trauma centers. We assessed (1) healing by callous formation on radiographs and the ability to weightbear comfortably; (2) patient function by their ability to sit, stand, lie on their sides, and how well they tolerated the implants; and (3) complications during the observation period. The minimum followup was 6 months (mean, 15 months; range, 6-40 months).
All 91 patients were able to sit, stand, and lie on their sides. Injuries healed without loss of reduction in 89 of 91 patients. Complications included six early revisions resulting from technical error and three infections. Irritation of the lateral femoral cutaneous nerve was reported in 27 of 91 patients and resolved in all but one. Heterotopic ossification around the implants, which was asymptomatic in all cases, occurred in 32 of 91 patients.
The anterior internal fixator provided high rates of union for the anterior injury in unstable pelvic fractures. Patients were able to sit, stand and ambulate without difficulty. Infections and aseptic loosening were reduced but heterotopic ossification and irritation of the LFCN are common.
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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Available from: Rahul Vaidya, Jan 02, 2014
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    • "It was also reported, however, that additional complications can occur at higher frequencies in patients treated with INFIX. The additional complications in the study included irritation to the lateral femoral cutaneous nerve in 30% of patients, although this complication resolved in all except one patient, and heterotopic ossification around the screw heads in 35% [12]. Some authors [13] [14] [16] recommend removal of the device in the operating room after approximately 12 weeks; however, it has been reported that some patients refuse implant removal because of a lack of symptoms and one patient underwent vaginal childbirth with the device in place without adverse effects [13]. "
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    ABSTRACT: Little is known about the mechanical properties of internal anterior fixators (known as INFIX), which have been proposed as subcutaneous alternatives to traditional anterior external fixators for pelvic ring disruptions. We hypothesised that INFIX has superior biomechanical performance compared with traditional external fixators because the distance from the bar to the bone is reduced. Using a commercially available synthetic bone model, 15 unstable pelvic ring injuries were simulated by excising the pubic bone through the bilateral superior and inferior rami anteriorly and the sacrum through the bilateral sacral foramen posteriorly. Three test groups were established: (1) traditional supra-acetabular external fixation, (2) INFIX with polyaxial screws, (3) INFIX with monaxial screws. Load was applied, simulating lateral compression force. Outcome measure was construct stiffness. The traditional external fixator constructs had an average stiffness of 6.21N/mm±0.40standard deviation (SD). INFIX with monaxial screws was 23% stiffer than the traditional external fixator (mean stiffness, 7.66N/mm±0.86SD; p=.01). INFIX with polyaxial screws was 26% less stiff than INFIX with monaxial screws (mean stiffness, 5.69N/mm±1.24SD; p=.05). No significant difference was noted between polyaxial INFIX and external fixators (mean stiffness, 6.21N/mm±0.40SD; p=.65). The performance of INFIX depends on the type of screw used, with monaxial screws providing significantly more stiffness than polyaxial screws. Despite the mechanical advantage of being closer to the bone, polyaxial INFIX was not stiffer than traditional external fixation. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Jan 2015 · Injury
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    • "Risk of secondary nerve damage due to compression following closed reduction in cases of simultaneous sacrum fractures. Irritation of the N. cutaneus femoris lateralis [25]. Loosening or dislocation of the fixation rod with loss of reduction [25]. "
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    ABSTRACT: Fractures of the pelvic ring including disruption of the posterior elements in high-energy trauma have both high morbidity and mortality rates. For some injury pattern part of the initial resuscitation includes either external fixation or plate fixation to close the pelvic ring and decrease blood loss. In certain situations - especially when associated with abdominal trauma and the need to perform laparotomies - both techniques may put the patient at risk of either pintract or deep plate infections. We describe an operative approach to percutaneously close and stabilize the pelvic ring using spinal implants as an internal fixator and report the results in a small series of patients treated with this technique during the resuscitation phase. Four patients were treated by subcutaneous placement of an internal fixator. Screw fixation was carried out by minimally invasive placement of two supra-acetabular iliac screws. Afterwards, a subcutaneous transfixation rod was inserted and attached to the screws after reduction of the pelvic ring.All patients were allowed to fully weight-bear. No losses of reduction or deep infections occurred. Fracture healing was uneventful in all cases. Minimally invasive fixation is an alternative technique to stabilize the pelvic ring. The clinical results illustrate that this technique is able to achieve good results in terms of maintenance of reduction the pelvic ring. Also, abdominal surgeries no longer put the patient at risk of infected pins or plates.
    Full-text · Article · Mar 2014 · BMC Research Notes
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    • "We have used monoaxial screws in situations that require excessive tension or added Crings (Synthes Spine) on the outside of the polyaxial screws where one might see excessive tension or on the inside for lateral compression injuries. This was performed in 2 cases where the construct failed, but the original belief was that the failure was due to cross threading the caps in excessively large individuals [8]. Owen et al. [13] have suggested using 2 infix devices for this type of problem. "
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    ABSTRACT: Purpose. Comparison of monoaxial and polyaxial screws with the use of subcutaneous anterior pelvic fixation. Methods. Four different groups each having 5 constructs were tested in distraction within the elastic range. Once that was completed, 3 components were tested in torsion within the elastic range, 2 to torsional failure and 3 in distraction until failure. Results. The pedicle screw systems showed higher stiffness (4.008 ± 0.113 Nmm monoaxial, 3.638 ± 0.108 Nmm Click-x; 3.634 ± 0.147 Nmm Pangea) than the exfix system (2.882 ± 0.054 Nmm) in distraction. In failure testing, monoaxial pedicle screw system was stronger (360 N) than exfixes (160 N) and polyaxial devices which failed if distracted greater than 4 cm (157 N Click-x or 138 N Pangea). The exfix had higher peak torque and torsional stiffness than all pedicle systems. In torsion, the yield strengths were the same for all constructs. Conclusion. The infix device constructed with polyaxial or monoaxial pedicle screws is stiffer than the 2 pin external fixator in distraction testing. In extreme cases, the use of reinforcement or monoaxial systems which do not fail even at 360 N is a better option. In torsional testing, the 2 pin external fixator is stiffer than the pedicle screw systems.
    Full-text · Article · Dec 2013
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