Kazuya Shinmura

Surgical site infection after total en bloc spondylectomy: risk factors and the preventive new technology.

BACKGROUND CONTEXT Surgical site infection (SSI) associated with instruments remains a serious and common complication in patients who undergo total en bloc spondylectomy (TES). It is very important that the risk factors for SSI are known to prevent it. PURPOSE The purpose of the study was to identify independent risk factors for SSI after TES and evaluate the positive effect of iodine-supported spinal instruments in the prevention of SSI after TES. STUDY DESIGN This is a retrospective clinical study. PATIENT SAMPLE One hundred twenty-five patients who underwent TES for vertebral tumor were evaluated. OUTCOME MEASURES Incidence rate of SSI, risk factors for SSI after TES, and safety of iodine-supported spinal instruments were the outcome measures. METHODS Risk factors for SSI were analyzed using logistic regression. In recent 69 patients with iodine-supported spinal instruments, the thyroid hormone levels in the blood were examined to confirm if iodine from the implant influenced thyroid function. Postoperative radiological evaluations were performed regularly. RESULTS The rate of SSI was 6.4% (8/125 patients). By multivariate logistic regression, combined anterior and posterior approach and nonuse of iodine-supported spinal instruments were associated with an increased risk of SSI. The rate of SSI without iodine-supported spinal instruments was 12.5%, whereas the rate with iodine-supported spinal instruments was 1.4%. This difference was statistically significant. There were no detected abnormalities of thyroid gland function with the use of iodine-supported instruments. Among the 69 patients with iodine-supported spinal instruments, 2 patients required additional surgery because of instrument failure. However, there were no obvious involvements with the use of iodine-supported spinal instruments. CONCLUSIONS This study identified combined anterior and posterior approach and nonuse of iodine-supported spinal instruments to be independent risk factors for SSI after TES. Iodine-supported spinal instrument was extremely effective for prevention of SSI in patients with compromised status, and it had no detection of cytotoxic or adverse effects on the patients.

A novel method to apply osteogenic potential of adipose derived stem cells in orthopaedic surgery.

Background A number of publications have reported that adipose derived stem cells (ADSCs) have the capacity to be induced to differentiate into osteoblasts both in vitro and in vivo. However, it has been difficult to use separate ADSCs for cortical bone regeneration and bone reconstruction so far. Inspired by the research around stromal stem cells and cell sheets, we developed a new method to fabricate ADSCs sheets to accelerate and enhance the bone regeneration and bone reconstruction. Purpose To fabricate ADSCs sheets and evaluate their capacity to be induced to differentiate to osteoblasts in vitro. Methods Human adipose derived stem cells (hADSCs) were employed in this research. The fabricating medium containing 50 µM ascorbate-2-phosphate was used to enhance the secretion of collagen protein by the ADSCs and thus to make the cell sheets of ADSCs. As the separate ADSCs were divided into osteo-induction group and control group, the ADSCs sheets were also divided into two groups depending on induction by osteogenesis medium or no induction. The osteogenic capacity of each group was evaluated by ALP staining, Alizarin Red staining and ALP activity. Results The ADSCs sheets were fabricated after one-week culture in the fabricating medium. The ALP staining of ADSCs sheets showed positive results after 5 days osteo-induction and the Alizarin Red staining of ADSCs sheets showed positive results after 1 week osteo-induction. The ALP activity showed significant differences between these four groups. The ALP activity of ADSCs sheets groups showed higher value than that of separate ADSCs. Conclusion The experiments demonstrated that ADSCs sheets have better capacity than separate ADSCs to be induced to differentiate into osteoblasts. This indicates that it is possible to use the ADSCs sheets as a source of mesenchymal stem cells for bone regeneration and bone reconstruction.

Increase of IL-12 following Reconstruction for Total En Bloc Spondylectomy Using Frozen Autografts Treated with Liquid Nitrogen

Background Total en bloc spondylectomy (TES) is a surgery designed to achieve complete resection of a malignant spinal tumor such as spinal metastasis. Although this procedure decreases the rate of local recurrence, it is questionable whether local control prolongs patient’s survival. We developed a “second-generation TES” that brings about TES enhancing antitumor immunity to prolong patient’s survival. Our purpose is to present a second-generation TES applied tumor-induced cryoimmunology and assess the immunity-enhancing effect after implementing this surgery. Methods We performed a retrospective review of prospectively collected data in second-generation TES as carried out in 56 cases. In second-generation TES, instead of harvesting autograft from the ilium or fibula, the resected lamina and vertebral body from TES are frozen using liquid nitrogen and used as grafted bone for spinal reconstruction. In recent 26 of the 56 cases, in addition to the TES procedure, a small amount of the tumor tissue from the resected tumor-bearing vertebra was also placed into liquid nitrogen. This small amount of tumor tissue was then implanted subcutaneously on one side of the axilla. In 52 of 56 cases, measurement of interleukin 12 (IL-12) was performed before surgery and at both 1 and 3 months after surgery. Results IL-12 increased after TES surgery in 38 of 52 cases (73.1%). The mean IL-12 relative concentrations at both 1 and 3 months after surgery, as compared to before surgery, were significantly higher (121±89 and 149±111%: P<0.05 and P<0.01). Conclusions Our results show that second-generation TES may provide not only a local radical cure but also a systemic immunological enhancement. Further prolonged survival in patients with a malignant spinal tumor is promising by second-generation TES.

Novel reconstruction technique using a frozen tumor-bearing vertebra from a total en bloc sponydylectomy for spinal tumors.

This article describes a novel reconstruction technique using frozen tumor-bearing vertebrae in total en bloc spondylectomy for spinal tumors. Instead of harvesting autograft from the ilium or fibula, the resected lamina and vertebral body from the total en bloc spondylectomy are frozen in liquid nitrogen and used as grafted bone for spinal reconstruction. A retrospective review of 56 patients was undertaken. As a result of this review, it was determined that this technique has the benefits of no pain at the bone harvest site, shortened operative time, decreased blood loss, and an additional antitumor immune response.

A histological examination of spinal reconstruction using a frozen bone autograft

Our aim was to compare the process of bone formation after reconstruction of the vertebral body using a titanium cage with either a liquid nitrogen-treated (frozen) bone autograft or non-treated fresh bone autograft. Twelve canine beagles underwent anterior reconstruction of the 5th lumbar vertebrae using a titanium cage and bone autograft. Bone formation was compared across four experimental groups: fresh bone autograft groups, with animals sacrificed at either 8 or 16 weeks post-reconstruction, and liquid nitrogen-treated (frozen) bone autograft groups, with animals again sacrificed at either 8 or 16 weeks post-reconstruction. Bone formation was evaluated histologically by calculating the proportion of ‘reaction’ and ‘mature bone’ regions at the ends of the cage, its center, and ventral/dorsal sides. The reaction region contained osteocytes with a nucleus and osteoblasts accumulated on the surface of an osteoid, while a laminar structure was visible for mature bone regions. For fresh bone autografts, the reaction and mature bone regions significantly increased from 8 to 16 weeks post-reconstruction. By comparison, for frozen autografts, the reaction bone region did not significantly increase from 8 to 16 weeks post-reconstruction, while the mature bone region did increase over this time period. The proportion of reaction bone was higher at the ends and dorsal side of the cage at 8 weeks, for both graft types, with greater bone formation at the center of the cage at 16 weeks only for the fresh bone autograft. Therefore, bone formation in the anterior spinal reconstruction site tended to be delayed when using a frozen bone autograft compared to a fresh bone autograft. The bone formation process, however, was similar for both groups, beginning at the ends and dorsal side of the cage adjacent to the surrounding vertebral bone.