Navigation-assisted bone tumor surgery may lead to better resection, function

Investigators from Korea found a mean registration error of less than 1 mm with navigation surgery.

Performing bone tumor resection using a navigation system can improve the accuracy of the surgical resection and help preserve limb function, according to researchers from Korea.

“Under navigated guidance, three-dimensional anatomy of the tumor and the surrounding normal tissue can be visualized during surgery,” Hwan-Seong Cho, MD, said during his presentation at the American Academy of Orthopaedic Surgeons annual meeting. “Precise control of the resection margin is possible, enabling us to achieve the resection margin determined preoperatively. In selected patients, this technique can be helpful in increasing the accuracy of surgical resection and in reducing the functional impairment.”

Malignant bone tumors

Cho and his colleagues studied patients with a total of 11 primary bone tumors or solitary bone metastases who underwent bone tumor resection and joint preservation limb surgery using a navigation system at Seoul National University College of Medicine since 2005. Preoperatively, the patients had malignant fibrous histiocytoma of bone, high-grade chondrosarcomas, Ewing’s sarcomas, osteosarcomas, and solitary bone metastases from rectal or thyroid cancers.

Surgeons used a navigation system during four internal hemipelvectomies, two partial sacrotomies and five joint preserving limb salvage procedures. They performed joint preserving limb surgery if the following conditions were met:

A T2-weighted spin-echo axial image shows a lobulated lesion with a high signal intensity confined to right sacral ala. Images: Cho HS

• the tumor was located in the metaphyseal region;
• the preoperative chemotherapy was estimated to be effective as evidenced by imaging studies; and
• the remaining epiphysis was expected to be more than 1 cm long after tumor resection with a 1 cm- to 2 cm-surgical margin.

The navigation system took a mean time of almost 51 minutes to set-up, and the investigators followed the patients for a mean of 18.5 months.

Accuracy

The investigators discovered that the mean registration error was less than 1 mm.

“The distances from the tumor to the resection margins on the pathologic examination were in accordance with those of the preoperative plans,” Cho said. The patients had a mean Musculoskeletal Tumor Society functional score of 28 points, and the investigators found no cases of local recurrence at the latest follow-up.

Soft tissues, blood loss

During the paper discussion, audience member Lawrence R. Menendez, MD, asked if the investigators used navigation to measure the surgical margins during the soft tissue resection.

“I used the navigation system for only the osteotomy,” Cho said. “For the soft tissue resection, I use conventional methods.”

Menendez noted that navigation has been used for soft tissue procedures in other fields such as neurosurgery.

Cho replied, “But, in the soft tissue sarcoma, we cannot technically attach the dynamic reference base.”

Another audience member asked if the investigators noticed a difference in blood loss during tumor resection when using navigation.

“I did not compare the blood loss between the conventional method and the navigation use, but I guess that there is no big difference,” Cho said.

A dynamic reference-base was fixed to the spinous process of L5. Tumor resection with wide margin was performed under navigation guidance.

The tumor was excised with an adequate surgical margin as planned and L5 nerve root and sacral nerve roots could be preserved.

For more information:

• Hwan-Seong Cho, MD, can be reached at Kyungpook National University College of Medicine, 200 Dongduk-ro Jung-gu, Daegu, 700-721, South Korea; 82-53-420-6322; e-mail: mdchs111@snu.ac.kr. He receives research or institutional support from Aesculap/B. Braun and Smith & Nephew.
• Lawrence R. Menendez, MD, is the Director of Orthopaedic Oncology at the University of Southern California University Hospital. He can be reached at 1520 San Pablo St., Suit e 2000, Los Angeles, CA 90033; 323-442-5830; e-mail: menendez@usc.edu. Neither source has any financial interest in any products or companies mentioned in this article.

Reference:

• Cho HS, Han I, Oh JH, et al. Bone tumor resection under navigation guidance. Paper #469. Presented at the American Academy of Orthopaedic Surgeons 76th Annual Meeting. February 25-28, 2009. Las Vegas.
• Cho HS, Kang HG, Kim HS, Han I. Computer-assisted sacral tumor resection. A case report. J Bone Joint Surg (Am). 2008;90(7):1561-1566.
• Cho HS, Oh JH, Han I, Kim HS. Joint-preserving limb salvage surgery under navigation guidance. J Surg Oncol. 2009 Mar 27. [Epub ahead of print]