Limb salvage procedures for children with osteosarcoma: an alternative to amputation

Magnetic Resonance Imaging for the Assessment of Long Bone Tumors

Background:

Wide resection margins of osseous tumors are associated with a low incidence of local recurrence, making accurate measurement of the intraosseous extent of primary malignant long bone tumors is crucial. We compared the intraosseous tumor extent assessed by magnetic resonance imaging (MRI) with the gross specimen to evaluate the accuracy of MRI.

Methods:

A total of 255 patients with primary malignant tumors in the long bones were included. Using MRI, we defined the length of tumor as the distance from the articular surface to the boundary between abnormal and normal marrow signal. The extent of the abnormal intraosseous signal was measured on unenhanced T1-weighted (T1WI) magnetic resonance images after chemotherapy. All gross surgical specimens were sectioned, and tumor extent was measured. Wilcoxon signed-rank test was used to test the differences between MRI and gross specimen findings. Spearman's correlation analysis was used to test the correlation between groups.

Results:

Median tumor length by gross specimen (112 mm; range, 45–300 mm) was longer than that by MRI (108 mm; range, 45–304 mm; Z = −6.916, P < 0.001). Of 255 images, tumor length was accurately represented on 27 T1WI magnetic resonance images, overestimated on 79 images, and underestimated on 149 images. The median difference between imaging and gross specimen measurements was 2.0 mm (range: 1.0–15.0 mm) for the 79 cases where tumor length was overestimated, and 5.0 mm (range: 1.0–18.0 mm) for the 149 cases where tumor length was underestimated. The Spearman correlation demonstrated a high correlation of tumor length on gross specimen with the tumor length on MRI (R = 0.99, P < 0.01).

Conclusions:

We conclude that preoperative MRI could be a useful method in determining intramedullary malignant bone tumor boundaries and may serve as an accepted assessment method of long bone tumors before limb-sparing surgery.

Outcome of lower-limb preservation with an expandable endoprosthesis after bone tumor resection in children

BACKGROUND

The optimal treatment of malignant pediatric lower-extremity bone tumors is controversial. Expandable endoprostheses allow limb preservation, but the revision rate and limited function are considered barriers to their use. This study investigated the functional, emotional, and oncologic outcomes of thirty-eight patients treated with an expandable endoprosthesis.

METHODS

A retrospective chart review was performed, and surviving patients were asked to complete the Musculoskeletal Tumor Society (MSTS) outcomes instrument and the Pediatric Outcomes Data Collection Instrument (PODCI). Additional data including the range of hip and knee motion, limb-length discrepancy, and total lengthening were also obtained.

RESULTS

Thirty-eight patients were treated with an expandable endoprosthesis, and twenty-six of these patients were alive at the time of the study. The mean global MSTS score was 26.1, and the mean global PODCI score was 85.8. The mean emotional acceptance and happiness subscores were high. The mean sagittal-plane hip motion in patients who had undergone replacement of the proximal aspect of the femur was 103°. The mean knee motion in patients who had undergone replacement of the proximal aspect of the femur, the distal aspect of the femur, or the proximal aspect of the tibia was 127°, 97°, and 107°, respectively. The mean lengthening at the time of skeletal maturity was 4.5 cm, and the mean limb-length discrepancy was 0.7 cm. Forty-two percent of the patients experienced complications, with ten patients requiring prosthesis revision and two of these patients requiring amputation.

CONCLUSIONS

Current technology does not offer a single best reconstruction option for children. Previous studies and the present series have indicated that physical and emotional functioning in patients treated with an expandable endoprosthesis are good but that complication rates remain high. Amputation and rotationplasty are alternative treatments if patients and their families are amenable to these procedures. The literature supports no single superior treatment among these three options with regard to physical or emotional health.

Resection arthrodesis of the ankle for aggressive tumors of the distal tibia in children

BACKGROUND

There is no consensus on the ideal treatment for malignant tumors of the distal tibia. Many favor amputation.

METHODS

Thirteen children, at an average age of 12 years (8 to 16 y) sustained conservative surgical treatment for a tumor of the distal tibia. All patients had "en bloc" resection of the tumor with ankle arthrodesis achieved by nail or plate accompanied by autograft.

RESULTS

The results were assessed retrospectively with an average follow-up of 8.8 years. Nine patients were in complete remission. Two patients had died. Two patients were lost to follow-up. Two patients had a local recurrence, which required amputation. There were 4 infections, which responded well to therapy. Four patients required additional bone grafting because of nonunion. Three patients required osteotomy for malalignment. Bone healing was achieved for the 9 patients seen at last follow-up. All were able to walk with an average functional score of 24.7/30 (23 to 26) on the Musculoskeletal Tumor Society score.

CONCLUSIONS

Several reconstructive techniques are available: mega prosthesis of distal tibia and ankle, reconstruction by vascularized fibula or by autograft. All series reported significant rates of infections, cutaneous necrosis, and nonunion.

DISCUSSION

Conservative treatment with ankle arthrodesis is a possible alternative to amputation for the management of malignant tumors of the distal tibia in selected patients. Survival results and functional outcome were good despite initial complications.

LEVEL OF EVIDENCE

This is a retrospectively therapeutic study graded level 2 as level of evidence.

Pediatric surface osteosarcoma: clinical, pathologic, and radiologic features

BACKGROUND

Osteosarcoma (OS) arising from the surface of bone is far less common than its intramedullary counterpart. Although surface OSs share some radiographic and clinical features, they can be divided into three distinct histologic subtypes.

PROCEDURE

We reviewed the clinical, radiographic, and pathologic features of 14 cases of pediatric surface OS treated at St. Jude Children's Research Hospital between 1970 and 2003.

RESULTS

Seven patients had parosteal, five had periosteal, and two had high-grade surface OS. The median age at diagnosis was 16.2 years (range, 13.6-18.5 years). Nine patients were male; 11 were Caucasian. None had metastatic disease at diagnosis. Primary tumor sites included distal femur (n = 6), mid to proximal femur (n = 4), and mid to proximal tibia (n = 4). All 14 patients were treated with surgery, and 7 (1 with parosteal, 4 with periosteal, 2 with high-grade tumors) received chemotherapy. One patient experienced pulmonary metastasis of periosteal OS 16 months and 43 months after diagnosis; long-term disease-free survival followed resection of the metastatic tumors. Twelve patients remained alive and disease-free a median of 10 years (range, 1.5-25.4 years) after diagnosis. One patient died of high-grade surface OS 1.8 years after diagnosis, and one patient with periosteal OS died of gastric cancer 18.2 years after diagnosis of OS.

CONCLUSIONS

The histologic grade predicts the clinical behavior of pediatric surface OS. Complete resection is the treatment of choice regardless of tumor subtype. Whereas chemotherapy is not indicated for parosteal OS, its role in periosteal OS remains controversial.

Use of extendable total femoral replacements in children with malignant bone tumors

Although rarely required, extendable reconstruction devices for replacing the entire femur offer children with malignant bone tumors the opportunity of a nearly normal development by overcoming an expected leg length discrepancy. Femoral integrity can be restored, allowing most patients to walk without the use of aids. There are no data available to provide evidence regarding long term results and morbidity in such patients. Six patients (range 2-12 years of age), three with osteogenic osteosarcoma and three with Ewing's sarcoma, were treated between 1988 and 1996 with custom made Stanmore extendable prosthetic total femoral replacements. One patient died 12 months after surgery because of complications relating to pulmonary metastasis. The remaining five patients were observed between 2.7 and 8.9 years (average, 5 years). No tumor recurrence has been recorded and no amputation has been performed. All surviving patients underwent an average of 9.4 operative procedures (range, 4-16 procedures) including 6.4 extension procedures (range, 3-10 procedures), and one prosthetic revision (range, 0-3 procedures). Five revisions in two patients were necessary because of infection, loosening of the prosthesis, mismatch between femoral head and acetabulum, or full extension of the extending mechanism. The functional results were measured in accordance with the Musculoskeletal Tumor Society rating score, with an average result of 77.3%. Total femoral replacement in a growing individual achieves good functional results yet has various risks for an uncertain outcome. Careful selection of the patient and realistic appraisal of the long term prospects are essential for successful treatment.

Present-day concepts in the management of sarcomas in children

1. NRSTS tumors represent 20-20% of all soft tissue sarcomas. In only the extremity primary are both RMS and NRSTS occurring with almost equal frequency. 2. Modern diagnostic imaging studies are invaluable to staging and preoperative planning. 3. The most important need is to standardize biopsy techniques, since an ill-conceived biopsy has an adverse effect on the definitive surgical procedure. 4. Standardization of surgical procedures is necessary to adequately define extent of local resection varying with site, type of tumor, and its biological behavior. Less radical procedures do not seem to have had an adverse effect in local control or survival as is evidenced in RMS of the orbit, vagina, and bladder. 5. Though complete surgical extirpation is the treatment of choice in RMS, incomplete surgical excision leaving microscopic disease can result in adequate local control following chemotherapy and radiation therapy. However, less than optimum responses to chemotherapy in the NRSTS makes it imperative that efforts be made to completely resect these lesions. 6. It is in the realm of initially unresectable primary lesion that the surgical oncologist's role be refined. Consideration here includes: (a) use of newer surgical techniques such as laser, or free microvascular grafts, (b) protocols to define the optimum timing of delayed surgery following preoperative chemotherapy with or without radiation therapy.

Surgical supportive care in pediatric oncology

An attempt has been made to describe some of the more practical surgical concepts and techniques which are used in pediatric surgical oncology. They do not fall into a coherent logical sequence and are not particularly specific to the cancer patient. But they do have one thing in common, namely they can all help to give more support to the child and his family. It should be clear that interaction between the doctor and the patient is also important. The support of one depends to a large extent on the support of the other.

Limb preservation in dogs with primary bone tumors

This article presents methods currently used for limb preservation in dogs with primary bone sarcomas. Emphasis is placed on diagnosis, proper patient selection, and perioperative management.