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Bone grinding has cemented its applications in the various sorts of the neurosurgeries. Generally, a rotating burr is used to remove a part of the bone to expose the tumors present underneath the bone. The abrasion caused by the grinding wheel causes a rise in temperature owing to the generation of the heat during grinding and would have severe consequences with the initiation of thermogenesis. To bridge this gap, an in-house experimental setup was developed to perform multi-pass rotary ultrasonic neurosurgical bone grinding. Three functional characteristics, namely rotational speed, feed rate, and amplitude, have been investigated using Taguchi L18 orthogonal array design. The regression equations have been obtained and validated with confirmation experiments using a random set of machining parameters. Further, machining parameters are optimized using genetic algorithm and confirmatory trials are performed using optimized conditions. The results of statistical analysis (ANOVA) revealed that the feed rate is the most significant parameter influencing the change in temperature during osteotomy. Nevertheless, the standard deviation was most affected by rotational speed. Furthermore, a comparative analysis has been carried out for conventional and rotary ultrasonic neurosurgical grinding. A hybrid approach using cumulative equivalent minutes (CEM43°C) and Arrhenius model has been used to predict the thermal damage caused to the human body’s tissues during bone grinding. The results obtained have been experimentally validated, and outcomes revealed that ultrasonically actuated grinding burr may prevent osteonecrosis and neural damage duly supported with infrared thermograms and graphical plots.

Nowadays polylactic acid (PLA) is widely used in orthopedics surgeries as implants material due to well mechanical characterization and biomedical properties. But the PLA implants suffer from slow degradation rate when it is used in real-life scenario. In the present research work, the PLA specimens using additive manufacturing technique are fabricated and further assessed for mechanical characterization and its degradation behavior with different parameters. The change in weight of scaffolds was measured using digital weight measure, and pH value was measured using pH meter. Morphology and elemental composition of PLA scaffolds were characterized by SEM and EDS, respectively, while compressive strength is measured by the universal testing machine. Apatite formation and biocompatible nature of fabricated scaffolds were analyzed by in vitro simulated body fluid study. The outcomes of characterization exposed that scaffold with 60% infill percentage had maximum porosity, which is beneficial for the apatite formation and osseointegration. The average change in compressive strength was measured as 49.79 MPa after 14 days and 46.11 MPa after 28 days, whereas the average change in pH value was measured as 5.67 and 5.27 after 14 and 28 days of incubation period, respectively. The degradation rate of specimen 3 was 27.92% less than that of specimen 1, 35.69% less than that of specimen 5, and 87.98% more than that of specimen 9. This study concludes the positive effect of process parameters on degradation rate and biocompatible behavior of PLA implants.