Treatment of simple bone cysts of the humerus by intramedullary nailing and steroid injection

Abstract

Background: Simple bone cysts (SBCs) are common benign lytic bone lesions in children. This study focused on exploring a clinical treatment method, minimally invasive intramedullary decompression and drainage with elastic stable intramedullary nailing (ESIN) combined with intralesional injections of steroids, and evaluated its effectiveness, complications and morbidity through functional and radiographic outcomes.

Methods: The postoperative recovery of 18 children who suffered from SBCs of humerus was evaluated (mean follow-up, 40 months) from January 2009 to December 2016. These patients (11 males, 7 females; 8 in the left, 10 in the right; mean age, 10.9 years old) were treated with minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids. The diagnosis was based on not only pre-operative typical medical images (X-rays/CT/MRI) but also surgical findings and pathological diagnosis. Radiological and functional outcomes were evaluated according to Capanna and Musculoskeletal Tumor Society (MSTS) score. The interclass differences were analyzed by t-test.

Results: According to Capanna and MSTS criteria, after treatment, 14 patients made full recoveries which was presented by all the cysts filled with bone tissue, and 4 patients made partially recoveries, which were presented by cystic spaces partially filled with low density bone. All the cysts responded to treatment method, and there was no cyst recurrence. All except 2 patients had good functional results. One of the two patients had irritation of the end of the nail and one patient had a valgus deformity.

Conclusions: Treatment for SBCs of humerus by minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids is safe, effective and convenient. The clinical effect is satisfactory and worth popularizing.

Keywords: Children; Combination therapy; ESIN; Simple bone cyst of humerus; Steroids.

Fig. 1

The scores of MSTS. The graph shows the preoperative and postoperative follow-up MSTS scores. Functional scores increased progressively until the end of postoperative 12 months, and then a plateau was reached and preserved throughout the rest of follow-up. There were significant difference between the MSTS scores of pre-operation and postoperative 3 months groups (P = 2.36277E-17) as well as those of postoperative 3 months and postoperative 24 months groups (P = 1.28483E-09). ***Significant difference, P < 0.001

Fig. 2

Radiographs of a 10-year-old boy who presented with pathological fracture of the left humerus. a-b Anteroposterior and lateral radiograph on admission. c-e MRI indicates a low signal on T1-weighted images and a homogeneous high signal on T2 weighting. f-k After the operation of minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids; At the interval points of postoperative 1 weeks, 2 months, 6 months, 9 months, 12 months, 14 months, the lesion is significantly smaller and shows signs of healing gradually. At 14 months, Radiograph show complete cyst healing (Capanna grade 1 healing). l-o At 16 months, the bone cyst has resolved, and then the intramedullary nails are removed. n-o Radiographs show complete cyst healing (Capanna grade 1 healing) after second surgery

Fig. 3

Radiographs of an 11-year-old boy who presented with pathological fracture of the left humerus. a-b Anteroposterior and lateral radiograph on admission. c-d MRI indicates a low signal on T1-weighted images and a homogeneous high signal on T2 weighting. e-f Three-dimensional CT image reconstruction and a sagittal CT scanning show fracture of proximal humeral bone cyst. g-l After the operation of minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids; At the interval points of postoperative 1 weeks, 2 months, 6 months, the lesion is significantly smaller and shows signs of healing gradually, the fracture gradually healed, Radiographs show complete cyst healing (Capanna grade 1 healing)

Fig. 4

Radiographs of a 10-year-old boy who presented with pathological fracture of the right humerus. a-b Anteroposterior and lateral radiograph on admission. c-d MRI indicates a big bone cyst in humerus. e-f After the operation, postoperative 1 weeks Radiographs show a good position of the fixation. g-h At 1 month after surgery, an accident is happened, posteroanterior X-ray shows a valgus deformity and a secondary fracture in the cyst region. i-j An”O″ shaped cast fixation was done after reduction in outpatient clinic, X-ray shows a valgus deformity. k-n At the interval points of postoperative 6 weeks, 2 months, Radiographs show a valgus deformity. o-p Radiographs show complete cyst healing while there is a valgus deformity, although the position of photograph was not satisfactory, there was no functional and visual defects