Clinical study of percutaneous injection of autologous bone marrow and allogeneic bone powder transplantation for bone cysts
Unicompartmental bone cysts in children occur in the long bone epiphysis of the extremities and are mostly detected after trauma with pathological fractures. Intracapsular scratching bone grafting and intracapsular injection of methylprednisolone are the more commonly used treatments, but have the disadvantages of being more invasive and having a higher recurrence rate [1] [2]. We treated 12 cases of unicompartmental bone cysts with percutaneous injection of autologous bone marrow plus allogeneic bone graft from March 2002 to September 2005 with satisfactory results, which are reported below.
Clinical data
I. General information
There were 12 cases in this group, including 5 males and 7 females; ages ranged from 6 to 21 years, with a mean age of 14 years. There were 6 cases of proximal femur and 6 cases of proximal humerus. One case of bone cyst was diagnosed due to pathological fracture caused by minor trauma, two cases of bone cysts were found by photos due to slight local soreness, and nine cases of bone cysts were found incidentally by photos for other reasons. All patients were routinely photographed with frontal and lateral X-rays and CT films of the affected limb, and the X-rays of the healthy limb were taken for control before treatment.
II. Surgical method
The patients were first placed in prone position, routinely disinfected according to the requirements of sterile surgery, spread sterile towel, and local infiltration anesthesia. The bone marrow was aspirated with a syringe containing 1 ml of heparin saline. 10 ml of bone marrow was aspirated from each puncture site and shaken to prevent coagulation. The bone marrow was aspirated with a syringe containing 1 ml of heparin saline. Under the guidance of “C” arm X-ray machine, a special bone puncture needle is used to penetrate into the cystic cavity of the bone cyst, and the straw-yellow cystic fluid is aspirated and tested. The bone marrow fluid without blood clots is drained and injected into the cystic cavity until there is a certain resistance feeling and then stopped. The average volume of bone marrow injected is 30-50 ml, and 10-20 g of lyophilized allograft bone powder is injected into the same bone puncture needle.
After the operation, the affected limb of femoral bone cyst should be braked by skin traction or absolutely avoid weight-bearing and strenuous activities of the affected limb, and the affected limb of humeral bone cyst should be braked by suspension fixation. 6 weeks later, the affected limb should be free from weight-bearing and gradually functional exercise. After the operation, the lower limb was gradually restored to weight-bearing walking and the upper limb was restored to joint activity and weight-bearing after the osteoclastic shadow was seen in the cystic cavity on the X-ray film every 1 month, but violence and trauma should still be avoided.
Results
The follow-up period ranged from 6 to 21 months, with a mean of 13.8 months. The cysts were evaluated according to Neer and Chigira’s X-ray evaluation criteria for bone cyst healing [3]. grade I: clear cysts with no change in size; grade II: visible cysts but with multiroom blurring; grade III: cyst sclerosis with small cavities remaining; grade IV: complete healing with disappearance of cavities. There were 8 cases of grade III and 4 cases of grade IV after 6 months of treatment in this group, and no complications were observed.
DISCUSSION
Bone cyst is a relatively common benign bone tumor-like lesion in clinical practice, which usually has no obvious clinical symptoms in the early stage and is often seen due to pathological fracture caused by minor trauma. The traditional treatment is intracapsular scratching and bone grafting of the lesion, but this therapy is not only invasive but also has a recurrence rate of up to 35%.1 In 1974, Scaglietti et al. reported treatment with intracapsular injections of methylprednisolone, but there was still a 20% recurrence rate and 10% of patients did not respond.2].
Hashemi-Nejad et al. did a retrospective analysis of 32 cases of unicompartmental bone cysts with percutaneous injection of methylprednisolone. According to Neer and Chigira’s X-ray evaluation criteria for bone cyst healing: grade IV in 4 cases, grade III in 20 cases, grade II in 2 cases, and grade I in 4 cases. the satisfactory rate of X-ray findings was 75%. 56% of patients required 2-3 injections, and 17% of patients received 6 injections. Thus, the results of this method of treatment were considered unsatisfactory. It is also believed that this method produces results similar to those of bone cysts with multiple boreholes with indwelling keratophores, so the healing of bone cysts is most likely due to multiple injections destroying the lining of the cyst wall rather than the effect of contributin [3].
Lokiec et al. reported 10 cases of bone cysts treated with intracapsular injection of simple autologous bone marrow in 1996 with more satisfactory results [4]. In this paper, we report the initial success of percutaneous injection of autologous bone marrow plus allogeneic bone powder transplantation in the treatment of 12 cases of unicompartmental bone cysts. Bone marrow can be divided into two major systems, hematopoietic and stromal, and its osteogenic capacity is derived from the bone progenitor cells of the stromal system. There are two types of osteogenic progenitor cells: one is inducible osteogenic precursor cell (IOPC), which is an undifferentiated mesenchymal stromal cell and exists in all connective tissues, and has various differentiation potentials. IOPC can be transformed into osteoblasts under the induction of BMP; the other is determined osteogenic precursor cell (DOPC), which exists only in the bone marrow stroma and bone surface and can differentiate into osteoblasts to produce new bone. Bone marrow is the only tissue that contains an abundance of directed and induced osteogenic progenitor cells [5]. The possible mechanism of percutaneous injection of autologous bone marrow plus allogeneic bone powder transplantation for the treatment of bone cysts is twofold: one is to achieve decompression of the cystic cavity through puncture; the other is to generate new bone through the directed osteogenesis of DOPC in the bone marrow and the differentiation of IOPC into osteoblasts induced by allogeneic bone BMP to generate new bone, resulting in gradual ossification and healing of the bone cystic cavity. According to our preliminary experience, percutaneous injection of autologous bone marrow plus allogeneic bone powder transplantation for the treatment of unicompartmental bone cysts is efficacious and has the advantages of minimal trauma, easy operation and high success rate, but its long-term efficacy still needs to be tested by long-term follow-up of more cases.
Typical case 1: male, 10 years old, giant bone cyst of right humerus
Preoperative radiograph
Intraoperative “C” arm X-ray for fluoroscopic localization
Healing of the bone cyst 4 months after surgery
Typical case 2: female, 22 years old, recurrence of right femoral bone cyst after bone scraping and grafting
Pre-operative X-ray
Healing of bone cyst 6 months after surgery