The geometric osteotomy: joint preservation in juxta-articular surface bone neoplasms

Computer-assisted surgical planning of complex bone tumor resections improves negative margin outcomes in a sawbones model

PURPOSE

Several technologies have been implemented in orthopedic surgery to improve surgical outcomes, usually focusing on more accurate execution of a surgical plan, but the development of the plan itself is also of great importance. The purpose of this study is to examine whether the use of preoperative computer planning platforms can improve the surgical plan?

METHODS

Eight surgeons created a preoperative surgical plan to resect a distal femur parosteal osteosarcoma in two settings: (1) Using a 2-D and 3-D CT scan only (current standard); and (2) using a computer-assisted planning platform. The plans were thereafter virtually executed using a novel surgical navigation system and a Sawbones model. This simulated model was derived from, and identical to, an actual patient scenario. The outcomes of interest were the number of positive margin cuts, and the volume of the resected specimen.

RESULTS

Using the surgical plan developed with computer assistance, there were 4 positive margin cuts made by 2 surgeons. In comparison, using standard planning, there were 14 positive margin cuts made by all 8 surgeons (p = 0.02). The resection volume was larger in the computer-assisted plans (96 ± 10 mm³) than in the standard plans (88 ± 7 mm³) (p = 0.055).

CONCLUSIONS

Computer-assisted planning significantly decreased the risk of a positive margin resection in this Sawbones tumor model used to simulate resection of a primary bone sarcoma. This proof of concept study highlights the importance of advanced surgical planning and sets the ground for developing beneficial surgical planning systems.

Cone-Beam Computed Tomography-Guided Navigation in Complex Osteotomies Improves Accuracy at All Competence Levels: A Study Assessing Accuracy and Reproducibility of Joint-Sparing Bone Cuts

BACKGROUND

The objective of this study was to assess the accuracy and reproducibility of a novel cone-beam computed tomography (CBCT)-guided navigation system designed for osteotomies with joint-sparing bone cuts.

METHODS

Eighteen surgeons participated in this study. First, 3 expert tumor surgeons resected bone tumors in 3 Sawbones tumor models identical to actual patient scenarios. They first performed these osteotomies without navigation and then performed them using a navigation system and 3-dimensional (3D) planning tools based on CBCT imaging. The 2 sets of measurements were compared using image-based measurements from post-resection CBCT. Next, 15 residents, fellows, and orthopaedic staff surgeons were instructed on the use of the system, and their navigated resections were compared with navigated resections performed by the 3 expert tumor surgeons.

RESULTS

One hundred and twenty-six navigated cuts done by the orthopaedic oncologists were compared with 126 non-navigated cuts by the same surgeons. The cuts violated the tumor in 22% (6) of the 27 non-navigated resections compared with none of the 27 navigated resections. The navigated cuts were significantly more accurate in terms of entry point, pitch, and roll (p < 0.001). The variation among the 3 surgeons when they used navigation was <0.6 mm for the entry cut and, on average, 1.5° for pitch and roll. All 18 surgeons then completed a total of 144 navigated cuts. The level of experience did not result in a significant difference among groups with regard to cut accuracy. Two cuts went into the tumor. The mean distance from the planned bone cuts to the actual entry points into bone was 1.5 mm (standard deviation [SD] = 1.4 mm) for all users. The mean difference in pitch and roll between the planned and actual cuts was 3.5° (SD = 2.8°) and 3.7° (SD = 3.2°) for all users.

CONCLUSIONS

Even in expert hands, navigated cuts were significantly more accurate than non-navigated cuts. When the osteotomies were aided by navigation, their accuracy did not differ according to the level of professional experience. CBCT-based metrics enable intraoperative assessments of cut accuracy and reconstruction planning.

CLINICAL RELEVANCE

CBCT-guided navigated osteotomies can improve accuracy regardless of surgeon experience and decrease the variability among different surgeons.

Intentional marginal resection of periosteal osteosarcoma in combination with neoadjuvant chemotherapy: A report of two cases and a review of the literature

A wide resection of the tumor with or without chemotherapy is the treatment of choice for periosteal osteosarcoma (PO) of the extremities, however, post-operative limb function and quality of life could be compromised. The present study reports two cases of 14-year-old boys who presented with progressively enlarging masses in their right knee regions. Computed tomography and magnetic resonance imaging scans indicated a fusiform space-occupying mass encircling the bone cortex, with stippled calcification. A diagnosis of PO was suspected. The histological findings confirmed the diagnosis of intermediate PO. Pre-operative chemotherapies were started, and good responses were detected by clinical evaluation and histological findings. Surgeries preserving the functional structures, including neurovascular bundles, tendons, muscles and epiphyses, were performed, followed by routine chemotherapy. The two patients experienced disease-free survival with follow-up times of 37 and 108 months, respectively. The patients were satisfied with the results of the treatment and they returned to normal life activities. These two cases indicated that a marginal resection of the tumor in conjunction with effective neoadjuvant chemotherapy may be an ideal alternative treatment for intermediate PO, since survival along with well-preserved limb function could be guaranteed. By contrast, a wide excision could result in the loss of limb function.

Periosteal Osteosarcoma: A Review of 17 Cases with Mean Follow-up of 52 Months

Purpose: Periosteal osteosarcomas are rare cartilage-rich bone tumours characterized by a juxtacortical eccentric position and are normally regarded oncologically as of intermediate to high grade.Their low incidence is mirrored by a small number of reported cases in the world literature. While there is general agreement that wide surgical excision is required, there is a paucity of evidence regarding adjuvant therapy. Previous reports have not indicated any consistent approach to this to allow appraisal.

Patients and methods: We report 17 cases treated at our centre over 16 years. Our policy was to use chemotherapy when the tumour showed any features of high grade.

Results: To date, no deaths have resulted from recurrence or metastasis of the tumour although there have been two deaths from other causes.

Discussion: Comparison of survival with existing studies is made to draw conclusions regarding future treatment of this condition in terms of surgical and adjuvant approaches.

Periosteal osteosarcoma – a European review of outcome

Periosteal osteosarcoma is a rare primary malignant bone tumour. Treatment is by surgical excision, but controversy remains about the value of chemotherapy. The members of the European Musculo Skeletal Oncology Society (EMSOS) collaborated to produce a dataset of 119 patients. The predominant site for the tumour was the femur, followed by the tibia. All but 2 patients underwent surgery, with 9 requiring amputation and the others having limb salvage. A total of 81 patients had chemotherapy, of whom 50 had neoadjuvant chemotherapy. There was no standard chemotherapy regime, but all patients receiving chemotherapy were given doxorubicin combined with at least one other agent. The overall survival was 89% at 5 years and 83% at 10 years. Eight patients developed local recurrence, of whom 5 died. Survival was related to appearance of local recurrence (P < 0.0001) but no other single factor. The use of chemotherapy was not shown to be a prognostic factor, but was used in two-thirds of the patients in this study.