Clinical application of 3D-printed biodegradable lumbar interbody cage (polycaprolactone/ß-tricalcium phosphate) for posterior lumbar interbody fusion.

A novel 3D-printed biodegradable cage composed of polycaprolactone (PCL) and beta-tricalcium phosphate (ß-TCP) in a mass ratio of 50:50, with stable resorption patterns and mechanical strength has been developed for lumbar interbody fusion. This is a prospective cohort study to evaluate the short- and mid-term safety and efficacy of this biodegradable cage in posterior lumbar interbody fusion (PLIF) surgery. This was a prospective single-arm pilot clinical trial in 22 patients with a follow-up time of 1, 3, 6, and 12 months, postoperatively. Clinical outcomes were assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Visual analogue scale (VAS) for leg pain and low back pain. Radiological examination included X-ray, CT scan, and three-dimensional reconstruction to evaluate surgical indications, intervertebral space height (ISH), intervertebral bone fusion and cage degradation. A total of 22 patients was included, with an average age of 53.5 years. Among 22 patients, one patient lost to follow-up and one patient withdrew from the clinical trial because of cage retropulsion. The remaining 20 patients showed significant improvement in clinical and imaging outcomes compared to the preoperative period. The overall mean VAS for back decreased from 5.85 ± 0.99 preoperatively to 1.15 ± 0.86 at the 12-month follow-up (p < .001); the VAS for leg decreased from 5.75 ± 1.11 to 1.05 ± 0.76 (p < .001); the JOA score improved from 13.8 ± 2.64 to 26.45 ± 2.46 (p < .001). The mean intervertebral space height (ISH) increased from 11.01 ± 1.75 mm preoperatively to 12.67 ± 1.89 mm at the 12-month follow-up and the bone fusion reached 95.2% (20/21 disc segments). Partial resorption (inferior to 50% compared with the initial cage size) were found in all cages (21/21). The clinical and radiological assessments showed that the application of 3D-printed biodegradable PCL/ß-TCP cages in PLIF yielded satisfactory results at the 12-month follow-up. In the future, long-term clinical observations and controlled clinical trials are required to further validate the safety and efficacy of this novel cage.

Characteristics, Prognosis, and Competing Risk Nomograms of Cutaneous Malignant Melanoma: Evidence for Pigmentary Disorders.

Purpose: Cutaneous malignant melanoma (CMM) always presents as a complex disease process with poor prognosis. The objective of the present study was to explore the influence of solitary or multiple cancers on the prognosis of patients with CMM to better understand the landscape of CMM. Methods: We reviewed the records of CMM patients between 2004 and 2015 from the Surveillance, Epidemiology, and End Results Program. The cumulative incidence function was used to represent the probabilities of death. A novel causal inference method was leveraged to explore the risk difference to death between different types of CMM, and nomograms were built based on competing risk models. Results: The analysis cohort contained 165,043 patients with CMM as the first primary malignancy. Patients with recurrent CMM and multiple primary tumors had similar overall survival status (p = 0.064), while their demographics and cause-specific death demonstrated different characteristics than those of patients with solitary CMM (p < 0.001), whose mean survival times are 75.4 and 77.3 months and 66.2 months, respectively. Causal inference was further applied to unveil the risk difference of solitary and multiple tumors in subgroups, which was significantly different from the total population (p < 0.05), and vulnerable groups with high risk of death were identified. The established competing risk nomograms had a concordance index >0.6 on predicting the probabilities of death of CMM or other cancers individually across types of CMM. Conclusion: Patients with different types of CMM had different prognostic characteristics and different risk of cause-specific death. The results of this study are of great significance in identifying the high risk of cause-specific death, enabling targeted intervention in the early period at both the population and individual levels.