My talk today is entitled Analysis of Bone Quality in Patients with One-Year Survival Following Spinal Fusion for Oncologic Disease. I'd like to thank my mentor, Dr. Chakravarty, for his assistance in this work. These are increasing incidents each year and are a major burden in oncologic therapy that leads to significant pain, morbidity, and neurologic dysfunction. Treatment of spinal metastases has evolved in recent years and can involve a variety of systemic and radiotherapies, as well as surgical decompression, often with instrumentation and fusion. Surgical decompression and fusion are often performed in a palliative manner to decrease the risk of neurologic complications. Bony fusion in this population takes a back seat to systemic therapy, radiotherapy, and other cancer-fighting treatments. With increasing efficacy of oncologic therapies and increased survival, we see the need to evaluate factors contributing to bone quality in patients with extended survival in order to optimize the bony fusion environment in these patients. Increased survival with inadequate fusion may lead to secondary complications. Our study incorporates a large cohort with a variety of primary tumor types as we assess the fusion rates at one year post-op and determine any factors that could present as barriers to care and that may affect fusion status in an oncologic population. We aim to address two main goals. The first is to describe the clinical profile of patients surviving at least one year from index surgery, and the second is to evaluate clinical and radiographic factors contributing to fusion status. In selecting our cohort, we screened all adults over the age of 18 with instrumented spinal fusion as part of oncologic treatment for spinal metastases between 2012 and 2022 at our institution. These patients had to have a minimum of one-year follow-up as well as post-operative CT scans at one year so that we could evaluate bone quality and fusion status. A total of 87 patients fit our inclusion criteria. A retrospective chart review was performed collecting demographic treatment and radiographic data. Statistical analysis was performed using student t-tests and Fisher's exact t-tests, where appropriate. Slide is a little busy, but describes our demographic data. The first two columns report demographic data surrounding the surgery and other patient-centered factors, and the column on the right highlights the distribution of primary cancers. Of note, the median age of this cohort was 61 1⁄2, with the median follow-up time at 43 1⁄2 months. Average number of levels fused was six, and constructs were represented in the semi-rigid, mobile, and junctional spine. Nearly half the patients had allograft, and the other half had synthetic graft. Some implants could not be found during chart review. As stated previously, the third column highlights the distribution of primary cancers represented in our cohort, with breast cancer being the most common at 22 patients, followed by renal cell carcinoma, multiple myeloma, thyroid cancer, and non-small cell lung cancer. As per the inclusion criteria, all patients had CT imaging at one year. We measured fusion status based on the Bridewell grading system that is listed in the top right corner. We considered grades one and two as fused, and three and four as unfused. BMI, post-op chemotherapy, post-op radiation, smoking history, and SYNs location did not significantly or negatively impact fusion status. Of note, chemotherapy and radiation did not harm fusion status, and fusion status was not negatively affected by SYNs location. This table describes Hounsfield units as measured on one year CT at fusion sites compared by fusion status, surgical location, and post-operative therapies. Of note, we found that patients that were fused at one year had higher Hounsfield units on CT compared to those who were not fused. Patients who received post-operative chemotherapy at one year had higher Hounsfield units compared to those who did not receive chemotherapy. Post-operative radiation approached a significant association with increased Hounsfield units. We suspect that with more patients this would become significant, although it wasn't in our analysis. Radiation alone did not significantly improve bone quality, although a small increase in Hounsfield units was seen, and there was no significant association in Hounsfield units based on the SYNs classification of location between the junctional, mobile, and semi-rigid portions of the spine. The change in Hounsfield units on one year CT between those who received chemotherapy and those who did not suggests that control of local and systemic disease burden may play a role in bone density of oncologic patients undergoing spinal fusion. Post-operative therapies did not appear to negatively impact fusion status. Additionally, fusion status was not impacted by SYNs location between the rigid, semi-rigid, mobile, and junctional regions of the spine. In the area of improving systemic and radiotherapies, as well as increased survival times of patients with oncologic disease, further work is indicated to elucidate factors that may promote fusion and encourage spine health, minimizing secondary symptoms of failed fusion status. This work may benefit the field of spine oncology. These are a few of my references that I used throughout the talk. Thank you for listening.

bone quality analysis

spinal fusion

oncologic disease

Hounsfield units

fusion status