Cancellous plastic

In orthopedics and trauma surgery, spongiosaplasty refers to the surgical insertion of bone tissue, preferably from the medullary canal ( cancellous bone ) to fill bone defects or to treat disorders of fracture healing ( pseudarthroses ). Spongiosplasty is performed almost exclusively in the body ( autogenous ) today, i.e. the bone is removed from a bone area in one operation and incorporated (implanted) into the target area of ​​the same patient during the same operation. In exceptional cases (very large defects) the bone material can also come from organ donors (homologous bones). In rare cases, maximum biological safety must be undertaken, since bone defects are not life-threatening diseases and therefore the transmission of blood-borne diseases (HIV, hepatitis, etc.) cannot be accepted under any circumstances.

Treatment concept

The aim of spongiosaplasty must be the form-fitting filling of a bone defect so that the implanted bone tissue can be integrated into the local bone tissue. Only after such an integration can the implanted bone take over its mechanical task, which z. B. consists of the carrying of body weight by the skeleton. In the case of fracture healing disorders, spongiosaplasty must firstly fill the defect between the unhealed ends of the fracture, and secondly initiate fracture healing through the fresh bone tissue. The bone cells and mesenchymal stem cells contained in the cancellous bone, but also the growth factors and the bone matrix, serve as scaffolding (structure).

Indications

Bone defects

Bone defects can have various causes. So can purely mechanically z. B. in the context of a traffic accident, a piece of bone can be torn from a fracture area and thus lost. In the event of a joint fracture, however, the softer sponge bone below the joint can be compressed (so-called impression fracture) and this can lead to a defect. Similar defects near the joints can also be found through bone cysts , bone inflammation (osteomyelitis) or bone tumors. These can be primary bone tumors or secondary bone tumors (bone metastases from tumors in other organ systems ). A completely different and very common type of bone defect is produced in orthopedic operations for axis correction or joint structuring, in which bones are severed and opened. Bone material (cancellous or corticospongious bone) must be introduced here to stabilize and fill the bony defect.

Fracture healing disorder

Fracture healing disorders (pseudarthroses) can be based on mechanical problems (instability) as well as a disruption of the biological healing factors: for example, the blood flow to the invoicing region or the blood flow to the entire affected extremity can be disturbed. Active or past inflammation of the bone can also prevent fracture healing.

Surgical technique

Extraction area

Bone structure in the thighbone (femoral condyle). Cancellous bone is surrounded by a thin layer of cortex. Anatomical preparation

The body's own bones with a large amount of cancellous bone (spongy bone) such as z. B. the pelvic bones. Large tubular bones such as B. the thighbone and the shinbone contain large amounts of cancellous bone, which can be used for cancellous plastic. So-called local spongiosaplasty is often used to fill defects in small quantities: For this purpose, the bone tissue is removed from the immediate vicinity of the defect zone. B. Removal from the spoke , for defects at the elbow joint removal from the elbow hook ( olecranon ).

Surgical procedure

Surgery with the use of spongiosaplasty is predominantly carried out under general anesthesia, because the extraction region and the target bone are usually not in an area that can be anesthetized by local anesthesia . First, in the first part of the operation, the bone defect is analyzed and its extent determined. With this specification, the necessary amount of cancellous material in the second part of the operation, for. B. can be taken from the iliac crest. For this purpose, a corresponding piece of the pelvic bone is removed either with a bone chisel, a saw or a bone punch. If a defined bone part is required, this piece of bone can be installed directly. However, if the bone defect is a cavity or a fracture healing disorder, the pelvic section must be comminuted with instruments (e.g. Luer forceps). Afterwards, these pieces of less than the size of a cherry pit can easily fill a defect and, by increasing the surface, can also be quickly integrated into the surrounding bone. The cancellous material must not be compressed in order to make it easier for osteoblasts to grow into the regeneration area.

Alternatives

Due to the defect zones and additional operating time that arise when using cancellous bone, the use of bone substitute material has been tested for many years . Some materials such as hydroxyapatite ceramics and tricalcium phosphate are already being used clinically as a replacement for autologous cancellous bone. Since these calcium-phosphate compounds are cell-free, they can only serve as a structured defect filler onto which the bone cells in the vicinity of the defect grow. Such behavior is known as osteoconduction, while cancellous bone has an active osteoinductive effect through its bone cells and growth factors. Calcium phosphate compounds are not suitable as "hardware" for treating disorders of fracture healing without the use of autologous cancellous bone. Instead, specific growth factors (e.g. bone morphogenetic protein ) and processed plasma factors are successfully used as “software” .

Individual evidence

1. ^ H. Matti: About the free transplantation of cancellous bone. In: Archives for Clinical Surgery . Volume 138, 1931.
2. ↑ H. Burchardt, WF Enneking: Transplantation of bone. In: Surgical Clinics of North America . 58, 1978, pp. 403-427.
3. ↑ SW Chase, CN Herdnon: The fate of autogenous and homogenous bonegrafts. An historical review. In: J Bone Joint Surg Am . 37-A, 1955, pp. 809-841.
4. ^ H. De Boer: Early research on bone transplantation. In: M. Aebi, P. Regazzoni (eds.): Bone Transplantation. Springer-Verlag, Berlin / Heidelberg 1989, pp. 7-19.
5. ↑ M. Aebi, P. Regazzoni, BA Rahn, F. Harder: Experimental model for bone allografts with and without immunsuppression and microsurgical revascularization. In: Helv Chir Acta. 51, 1985, pp. 641-644.
6. ^ LF Bush: The use of homogenous bone grafts. A preliminary report on bone bank. In: Journal of Bone and Joint Surgery (American). Volume 29-A, 1947, pp. 620-628.
7. ↑ A. Emmermann, NM Meenen, JV Wening: Organization of a bone bank under the aspect of increasing incidence of HIV infections. In: magazines accident medicine. 207, 1989, p. 375.
8. ↑ K. Draenert, Y. Draenert, EG Hipp: The primary metaphyseal bone healing and the healing of the stably fixed autologous cancellous bone transplant. In: Journal of Orthopedics. Volume 118, 1980, p. 647.
9. ^ R. De Souza-Ramos: Osteogenetic Induction. In: Journal of Orthopedics. Volume 118, 1980, pp. 781-787.

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