Elastic intramedullary nailing and DBM-bone marrow injection for the treatment of simple bone cysts

Abstract

Background: Simple or unicameral bone cysts are common benign fluid-filled lesions usually located at the long bones of children before skeletal maturity.

Methods: We performed demineralized bone matrix and iliac crest bone marrow injection combined with elastic intramedullary nailing for the treatment of simple bone cysts in long bones of 9 children with a mean age of 12.6 years (range, 4 to 15 years).

Results: Two of the 9 patients presented with a pathological fracture. Three patients had been referred after the failure of previous treatments. Four patients had large lesions with impending pathological fractures that interfered with daily living activities. We employed a ratio to ascertain the severity of the lesion. The extent of the lesion on the longitudinal axis was divided with the normal expected diameter of the long bone at the site of the lesion. The mean follow-up was 77 months (range, 5 to 8 years). All patients were pain free and had full range of motion of the adjacent joints at 6 weeks postoperatively. Review radiographs showed that all 7 cysts had consolidated completely (Neer stage I) and 2 cysts had consolidated partially (Neer stage II). Until the latest examination there was no evidence of fracture or re-fracture.

Conclusion: Elastic intramedullary nailing has the twofold benefits of continuous cyst decompression, and early immediate stability to the involved bone segment, which permits early mobilization and return to the normal activities of the pre-teen patients.

Figure 1

We arbitrarily employed a ratio to ascertain the severity of a simple bone cyst. The extent of the lesion on the longitudinal axis was divided with the normal expected diameter of the long bone at the site of the lesion. The presented in this study method of treatment has been performed in large unicameral bone cysts that occupied more than 2 times the physiologic diameter of the long bone at the site of the lesion.

Figure 2

(A) A cystogram was performed and tissue was obtained for histological examination. (B) Under image-intensifier control, kirschner wires were drilled in appropriate positions on both medial and lateral cortices. (C) The entry holes of the nails were created with cannulated drills over the kirschner wires, and the nails were directed to pass through the bone cyst, one at a time. (D) Iliac crest bone marrow was mixed with demineralized bone matrix and the mixture was injected at the cyst.

Figure 3

(A) Plain radiograph and (B) magnetic resonance imaging of the right humerus of a 7 year-old boy with a simple bone cyst. The patient had previous steroid injections. (C) Anteroposterior and (D) lateral radiographs after intramedullary nailing and injection of demineralized bone matrix and autologous bone marrow from the ipsilateral iliac crest. (E) Anteroposterior and (F) lateral radiographs at 31 months after the operation show complete healing of the cyst (Neer stage I).

Figure 4

(A) Plain radiograph and (B) computed tomography scan of a 6 year-old boy with a simple bone cyst at the right proximal femur. (C and D) Intramedullary nailing and injection of demineralized bone matrix and autologous bone marrow from the ipsilateral iliac crest was done.(E and F) Plain radiographs of the right proximal femur show a subcapital femoral neck fracture after a fall from a bike three weeks postoperatively. (G) Anteroposterior and (H) lateral radiographs of the right proximal femur nine months postoperatively, show thickening of cortex and healing of the cyst (Neer stage II).

Figure 5

A bony plug (arrow) may cause venous obstruction and increased pressure of the interstitial fluid that may lead to the formation of a unicameral or simple bone cyst.