Elsevier

Injury

Volume 46, Supplement 4, October 2015, Pages S114-S120
Injury

The cement-augmented transiliacal internal fixator (caTIFI): an innovative surgical technique for stabilization of fragility fractures of the pelvis

https://doi.org/10.1016/S0020-1383(15)30029-2Get rights and content

Abstract

Introduction

Analyzing the different age groups in a population who suffered a pelvic ring fracture it becomes obvious that there are important differences between the pelvic ring lesions of an elderly patient compared to a young adult concerning trauma mechanism, fracture pattern and therapeutic options. In the elderly patient it is very important to achieve maximum of stability if surgery is necessary in order to avoid early failure of the ostheosynthesis under mobilization with full weight bearing.

Patients and methods

15 patients (14 female) with fragility fractures of the pelvis that required surgical stabilization were eligible to participate in this study from December 2012 to December 2014. Such details were documented and analysed as patient demographics, mechanism of injury, fracture classification, operative treatment and postoperative radiological parameters of achieved bone-implant interface.

Results

The average age of the patients was 79.9 years (SD 9.0 years). According to Rommens five patients had a fragility fracture of the pelvis Type II-c, one a Type III-c, six a Type IV-b and three a Type IV-c. Four patients were treated by a cement augmented transiliac internal fixation (caTIFI). Seven patients received a cement augmented iliolumbar fixation. In all these patients the Schanz screws applied to the ilium were placed in an oblique dorsoventral direction into the supraacetabular bone canal (mean length of screws 100 ± 20mm, max. 135mm, min. 70mm). Even though in four patients the iliosacral joint was hit tangential and one cortex perforation without any cement leakage appeared no revision surgery was necessary. Overall the clinical findings including mobilisation with full weight bearing showed a sufficient mechanically stability in all patients.

Conclusion

The focus of this study was to describe the modified surgical technique of the caTIFI with placing the Schanz screws from the posterior superior iliac spine to the anterior inferior iliac spine into the supraacetabular bone canal. Usage of cannulated and perforated Schanz screws gives the opportunity to control the correct position of the screws before implanting them. Another advantage is that additional stability can be obtained by cement augmentation. We believe that the new technique of the caTIFI provides a greater intraoperative versatility and a greater mechanical stability for fragility fractures of the pelvis.

Introduction

Even though the incidence of pelvic ring fractures is low (0.3 to 8%) [1], an increase over the last two decades can be detected. Demographic data show that especially the incidence of pelvic fractures in the group of over-85-year-old women compared to the overall incidence increased disproportionately high [2]. Looking at data from the German Pelvic Trauma Registry (DGU) 68% of pelvic fractures occurred in patients older than 65 years, with a peak at 85 years, predominantly in females (57%) [3]. These are mainly injuries caused by low energy trauma or even without any trauma (insufficiency fractures). In comparison to the high energy pelvic trauma that leads to transsacral, transiliosacral and transiliac posterior instability, the pelvic ring fracture in the elderly involves mainly sacral fractures with or without involvement of the sacro-iliac-joint leaving the sacro-iliac ligaments intact. There are different existing options to treat these injuries including transiliac bridging procedures (e.g. sacral bar, transiliac internal fixator, ilio-iliac plate), lumbopelvic fixation techniques, or ilio-sacral screw fixation [4].

None of the currently used techniques has been proven to be superior, neither in clinical studies nor in biomechanical analyses. However, especially for the elderly, it is very important to choose an osteosynthesis that allows immediate full weight bearing after operative treatment because this population is often not able to do partial weight bearing and mobilization is mandatory to prevent complications. Another fact is that the elderly patients often present with many comorbidities and therefore, low invasive procedures are preferable.

For the classification of the pelvic ring lesions [5, 6], the system of Tile, adopted by the Association for the Study of Internal Fixation/Orthopaedic Trauma Association (ASIF/OTA) is currently accepted worldwide [7, 8]. In correlation to the classification system for fractures of the extremities developed by the “Arbeitsgemeinschaft fĂŒr Osteosynthesefragen” (AO), Tile distinguishes between three degrees and types of instability, which are easy to discriminate: stable pelvic ring lesions, rotationally unstable lesions and rotationally and vertically unstable pelvic ring lesions. Further discrimination is based on morphologic criteria. The classification system has a high inter-observer reliability [9] and is well related to injury severity and outcome [10, 11].

With regard to the mechanism of injury, it is well accepted that there are important differences between pelvic ring lesions of an elderly injured patient compared to a young adult. Specifically the osteoporotic structure of the bone of an elderly patient leads to the situation that low-energy accidents and even normal physiological loads can lead to a fatigue fracture of the sacrum and the pelvic ring. Even though fragility fractures of the pelvic ring lead to bone disruption, the thick dorsal sacroiliac, sacrotuberal and sacrospinal ligaments remain intact and keep the pelvic ring in its anatomical borders. The fracture fragments can move within these borders and this can generate pain to the patient secondary to micromotion instability. This kind of vertical and rotational instability is not comparable to that of an OTA 61 Type C fracture of young adults [12, 13]. Therefore, a new comprehensive classification system for fatigue fractures of the pelvis was presented 2013 by Rommens and Hofmann [4]. It is based on clinical and radiological criteria and reflects four categories of increasing instability. Lesions within the groups are distinguished by the localization of the instability. Furthermore the classification system gives hints for the extent of surgical therapy and type of fixation, (Table 1).

In 2004, the trans-iliacal internal fixator (TIFI) was described in a prospective study including 31 patients with vertical shear injuries of the pelvis to be a save and minimal invasive surgical technique for stabilization of sacro-iliac joint disruptions and sacral fractures [14]. After longitudinal incision of the fascia the pedicle screws are placed into the posterior superior iliac spine in cranio-caudal direction and the transverse rod can be placed in a minimal invasive manner below the fascia of the spinal muscles. This way the injured hemipelvis is fixed angular stable to the non-injured side. Out of 62 inserted pedicle screws none was positioned incorrectly. Overall, one loosening of a pedicle screw and two superficial wound infection occurred in this study.

To achieve the highest stability by internal fixation with pedicle-screws and rods, a maximum diameter and length of the pedicle-screws is recommended [15]. Especially in osteoporotic bone this is necessary to prevent early failure of the internal fixation. Schildhauer et al. analyzed in a radiographic morphometric study of 40 trauma patients (21 males, 19 females; in the age of 16 to 78 years) the optimal bone corridor to place screws for iliolumbar fusion to treat spinal injuries of the low lumbar spine, sacral or dorsal pelvic ring fractures. He could show that the path from the posterior superior iliac spine to the anterior inferior iliac spine had the largest bony canal lengths, with 141mm in male and 129 mm in female patients. Furthermore, the width of this supraacetabular bone canal allows the placement of implants with a diameter of 8-mm in male and 6- to 7-mm in female patients. Schildhauer proposed that for an optimized iliac screw placement for lumbopelvic fixation appropriate pedicle screws should be placed into this bone stock [16]. The insertion of the screws should be done under intraoperative fluoroscopic control using obturator oblique–outlet and standard lateral pelvic views (Fig. 1).

Gaensslen et al. confirmed the results of Schildbauer and described the safe percutaneous placement of Schanz screws in the so called “supraacetabular bone canal” of the ilium bone to treat OTA 61 Type B and Type C fractures by a ventral external fixator [17]. Out of 64 supraacetabular external fixator applications (108 Schanz screws) a primary perforation of the Schanz screw into the small pelvis was seen in just two patients (3%).

Cement augmentation is an option to improve the fixation stability of the implant in osteoporotic bone. Cement augmentation of screw fixations in osteoporotic sacral fractures was shown to lead to adequate pain reduction and recurrence of mobility [18, 19, 20].

In this paper, we suggest a minimally invasive stabilization technique for osteoporotic pelvic ring fractures using a cement augmented internal fixator with Schanz screws that facilitates immediate full weight bearing.

Section snippets

Patients and methods

Results

15 patients (14 female) with fragility fractures of the pelvis were diagnosed according to the trauma mechanism and an assured or assumed underlying osteoporosis. Eleven of them suffered a fall from standing height and for three patients recurrent simple falls were recorded as trauma mechanism. One patient suffered a pelvic ring fracture without any trauma.

The average age of the patients with fragility fractures of the pelvis was 79,9 years (SD 9,0 years). The youngest patient was 49years and

Discussion

Improvement of fixation of the posterior elements of the pelvic ring in elderly patients with underlying osteoporosis and related outcomes has received a lot of attention lately [24, 25, 26, 27, 28, 29, 30, 31].

The method described in this paper is a safe and low invasive procedure that provides sufficient stability for full weight bearing in patients with osteoporotic pelvic ring injuries. Four perforations of the iliac cortex without need for revision were recorded. These perforations were

Limitations

Since the number of patients (n = 15) included in this retrospective study is small we were unable to carry out any statistical evaluation.

Conclusion

The main focus of this study was to describe the modified surgical technique of the cement augmented trans-iliacal-internal fixator (caTIFI) with placement of the Schanz screws from the posterior superior iliac spine to the anterior inferior iliac spine into the supraacetabular bone canal rather than placing them in a cranio-caudal direction into the posterior superior iliac spine. Usage of cannulated and perforated Schanz screws gives the opportunity to control the correct position of the

Acknowledgment

We like to thank Nadine Hausmann for assistance for data acquisition.

Conflict of interest

The authors are not compensated and there are no other institutional subsidies, corporate affiliations, or funding sources supporting this work unless clearly documented and disclosed.

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