Currently, it is challenging to surgically repair bone defects caused by bone tumors. Several methods are used to treat such defects, such as artificial bone24, allograft bone12, bone cement4, autograft bone11, 25, bone transport26 and tumor bone inactivation and replantation27. Although artificial bones can repair the defect area, the mechanical stability of such bones is poor, and autogenous bones do not heal effectively. In addition, allograft bone faces challenges including rejection, broken bone resorption, nonunion, fracture, and infection. On the other hand, autologous bone overcomes these challenges, but the supply is limited, causing a secondary trauma and bone defect to the patient. Moreover, bone transport provides good repair of large bone defects as it exploits the healing ability of the body. Thus it’s widely adopted in bioremediation. However, this approach is time-consuming, and also difficult to take care of the external fixator. Additionally, its efficacy is limited by infection, pain, and psychological problems.
Inactivation of bone tumors and replantation is an effective method used to treat low grade nonosteolytic malignant bone tumors. The primary benefit of this technique is that scaffolds for bone tumors have no tumorigenic activity, kill tumor cells through high-temperature heating, retains the appearance and mechanical support of the residual bone, and do not cause exclusion compared with allogeneic bone. It is also much cheaper than the allogeneic bone. Elsewhere, various methods have been noted to inactivate tumors including high-temperature water bath inactivation, in vitro irradiation inactivation27, 28, liquid nitrogen inactivation29, and pasteurization inactivation10, 30. Studies have enumerated that pasteurization has therapeutic effects as a biologic reconstructive option. In the study, 80% of the patients survived over 20 years and 62% of the patients had no complications, but it is not ideal for the long term30. However, hypothermia inactivation of the bone tumor using hyperosmotic saline is an effective approach to inactivate tumor cells. This method retains the activity of collagen fibrin and protein effectively which may be associated with hyperosmotic saline used as the protein stabilizer31. Therefore, inactivated bone tumor allow integration of grafted bone and autogenous bone, and retains the shape and mechanical strength of the original bone defect. Furthermore, it is a relatively inexpensive treatment method, making it a common method in clinical practice. Despite these benefits, large segments of autogenous bone are inactivated, the bone loses its biological activity, and cannot participate in the metabolism of normal bone tissue or integrate with autogenous bone tissue. Hence, for long-term applications, continuous auxiliary internal fixation is needed to maintain mechanical stability.
In the case of a bone tumor adjacent to a joint, excision of large segments of the joint requires extensive joint reconstruction, resulting in reduced joint function and a similar risk of infection to other internal plants. Therefore, it is recommended that large active bone tissue should be retained as much as possible to maintain bone biomechanics, metabolism and prevent infections and preserve the integrity and function of adjacent joints. However, despite its limited indications, hemicortical resection followed by inactivation and replantation is recognized and applied by many scholars9–11, 29. Campanacci was the first to report the application of hemiectomy in bone tumor surgery32. Also, some scholars have used hemiexcision for the surgical treatment of high-grade osteosarcoma. It has been noted that it is suitable for eccentric bone tumors, but its long-term effects remain elusive29. In particular, hemiexcision is more predominantly used for low-grade malignant tumors10, 12, 33–35. The benefits of hemiexcision include; tumor resection can be expanded, preserves the stability and integrity of adjacent joints, and enhances the residual normal bone mechanics using autologous or allogeneic bone grafting, matches the size of the original bone defect accurately, and has no risk of disease transmission. Of note, the initial safety margin of tumor resection is crucial to the treatment effect. Factors such as tumor location, shape, and size pose challenges to the effective application of hemibone resection. Due to the irregular shape of the tumor, and the restriction of the surgical field of view, surgeons may have to make certain plan changes during the osteotomy procedure. This may lead to the unsafe tumor resection border and the recurrence of residual tumor. For malignant bone tumors at the distal end of the posterior femur, it is difficult to preserve blood vessels as well as joint function35.
In the past, no method was available to make three-dimensional measurements on the tumor before surgical resection. However, computer technology has enabled this measurement to be made, thus achieving a higher matching degree between the tumor defect removed and the bone graft reconstructed22. Another method used to accurately remove a tumor from bone is the surgical navigation robot, but this tool is expensive and not readily available in ordinary hospitals. Recently, 3D digital reconstruction and 3D printing of osteotomy guide plate technology have improved osteotomy for hemibonectomy of bone tumors. The 3D reconstruction of the bone tumor is achieved using a three-dimensional CT scan which transmits the data into a 3D reconstruction software to establish a 3-dimensional model. This technique reveals the tumor after printing, thus allowing doctors to make a plan for the resection border. The corresponding resection guide plate can be fabricated according to the plan22. Theoretically, the safe boundary of osteotomy for this method is more reliable, and the chances of postoperative recurrence are lower. Moreover, with the assistance of the osteotomy guide plate, the time needed for osteotomy localization is relatively shorter, which reduces the operation time and in turn decreases blood loss, thus making it more effective in the rehabilitation of patients. Using the osteotomy guide plate, most of the bone tumor can be removed as a whole, rather than unplanned lumps. After inactivation treatment, the original shape of most of the bone tumor is maintained which creates a very high matching degree with the bone defect site. This ensures good fixation of bone blocks and also shortens the operation time. Overall, this method results in good postoperative recovery and functional recovery.
Previous studies have reported that fractures, infections and incomplete resection contributes to the development complications of hemiexcision. Specifically, fracture is one of the leading cause (10% − 18%)12, 36. In 2014, some scholars used computer-assisted surgery to design an allograft bone graft to repair the bone defect of hemibonectomy. They noted that the method achieved resection and reconstruction precisely with less time-consuming and also reduced the incidence of fracture22. Therefore, 3D printed osteotomy guide plate can be used to perform accurate osteotomy based on the preoperative surgical plan, without any intraoperative or postoperative fractures. Herein, the inactivated bone tissue transplanted back into the patient perfectly matched with the original bone defect, shortening the time taken to reconstruct the bone defect and adjust the bone mass. Besides, our short-term postoperative follow-up results enumerated no recurrence in all 10 patients. This implies good patient selection and safe tumor resection boundary. We also achieved accurate R0 resection and successful reconstruction even for adjacent joint lesions, and this perhaps may have contributed to the highly preserved joint function. Functional scores of the affected limbs after surgery were above 24 points in all patients, while patient satisfaction was very high. This finding is consistent with the recent reports by Japanese scholars37 and also exceeds scores reported in a review by Dutch scholars9. Therefore, this surgical approach is effective for the removal of bone tumors and bone reconstruction. High short-term efficacy following inactivation and replantation of hemibone resection for highly malignant bone tumors has been reported29. This indicates that it is possible to achieve an effective safe boundary for tumor control. However, the long-term efficacy of our method should be investigated further to confirm these intriguing findings, especially in follow-up studies.
In summary, digital three-dimensional reconstruction is a valuable technique for formulating osteotomy boundary and osteotomy guide plate assisted osteotomy, which makes hemibone resection more convenient, faster, and reduces the risk of postoperative complications, and lowers the recurrence rate. Furthermore, the method used herein is cheap, reliable, and results in quick recovery. Notably, this is important for reserving the joint function regarding the tumor adjacent to the joint. Despite these benefits, we acknowledge that hemiexcision has its inherent limitations. Among them is the risk of postoperative recurrence and insecure surgical boundaries. The follow-up period for patients in this study is relatively short, and thus a longer follow-up duration is needed to test the long-term effect of this surgical method. Also, the current digital three-dimensional reconstruction does not accurately identify the tumor tissue, making it difficult to achieve intelligent grasp recognition. Therefore, manual intervention is required to determine the tumor boundary. We believe that with the further advancements in imaging, digital technology, and artificial intelligence, these problems will be gradually solved, and hemibonectomy will yield better therapeutic effects.