Approach to standardized material characterization of the human lumbopelvic system—Specification, preparation and storage

Abstract

The complexity of the osseo-ligamentous lumbopelvic system has made it difficult to perform both, the overall preparation as well as specimen harvesting and material testing with a reasonable amount of time and personnel. The logistics of such studies present a hurdle for reproducibility. A structured procedure was developed and proved, which allows all necessary steps to be carried out reproducibly and in a reasonable time. This enables the extraction of 26 soft tissue, 33 trabecular and 32 cortical bone specimens from this anatomical region per cadaver. The integrity of the specimens remains maintained while keeping requirements within manageable limits. The practicability of the intended five-day specimen harvesting and testing procedure could be demonstrated on five test and two pre-test sequences. The intended minimization of physical, biological, and chemical external influences on specimens could be achieved. All protocols, instructions and models of preparation and storage devices are included in the supporting information. The high grade of applicability and reproducibility will lead to better comparability between different biomechanical investigations. This procedure proven on the human pelvis is transferable to other anatomical regions.

Approach to standardized material characterization of the human lumbopelvic system – Testing and evaluation

“…Fifteen samples were lost primarily due to harvesting failures (assessment code B01 in the Supporting Information S1), damage during harvesting (B02), anatomical abnormalities (A00), geometric conditions (A07), or non-compliance with the harvesting protocol (B16). These issues have been documented in a previous publication [19] and in Supporting Information S4. Additionally, seven specimens were excluded due to unspecific failure during testing (D02) and dislocation (D03) or due to a combination of strong individual influences (G02) such as significant geometric deviation.…”

“…This includes values such as dry, ash or bone mineral density. As described in our previous publication [19], we perform patient-specific computer tomography (CT) scans of the complete lumbopelvic complex. By adding a reference phantom, the density distribution of the material may be derived from the retained houndsfield units according to Anderson et al [44].…”

“…Comparative studies [13,14] have shown that variability in material parameters can be pronounced and is strongly dependent on the location and type of harvesting for both bony and soft tissue structures [6,15–18]. A previous study addressed the relevance of standardization of preparation and storage of biomechanical specimens under the aspect of reproducibility [19]. Here, we extend that investigation to the testing and evaluation of the samples collected in this way.…”

“…So, the primary reasons that the soft tissue specimens were excluded were as follows: harvesting failures (B01), anatomical abnormalities (A00), and non-compliance with the harvesting protocol (B16). As specified in the previous publication [19] and in accordance with the Terminologica Anatomica [37], the classification here is based on planar connective tissue structures called fascia and band-like structures called ligaments. This also corresponds more closely to the structural implementation differentiation in FE simulations.…”

“…The authors declare that all of the experiments were performed according to the ethical principles of the Declaration of Helsinki. The collection of cadaveric specimens was carried out following a previously established protocol for the standardization, preparation, and preservation of human tissue samples [19]. A total of seven human lumbopelvic systems with previously defined ligamentous apparatus were tested.…”