Approaches to ventriculoperitoneal shunt scalp erosion: countersinking into the calvarium. Illustrative case.

BACKGROUND: Ventriculoperitoneal shunting (VPS) is a standard procedure for the treatment of hydrocephalus, and the management of its complications is common in the practice of pediatric neurosurgery. Shunt exposure, though a rare complication, can occur because of thin, fragile skin, a young patient age, protuberant hardware, poor scalp perfusion, and a multitude of other patient factors. OBSERVATIONS: The authors report a complex case of VPS erosion through the scalp in a young female with Pfeiffer syndrome treated with external ventricular drainage, empirical antibiotics, and reinternalization with countersinking of replaced shunt hardware into the calvarium to prevent internal skin pressure points, reduce wound tension, and allow wound healing. LESSONS: Recessing the shunt hardware, or countersinking the implant, into the calvarium is a simple technique often used in functional neurosurgical implantation surgeries, providing a safe surgical strategy to optimize wound healing in select cases in which the skin flap is unfavorable.

Evaluation of Stress Distribution during Insertion of Tapered Dental Implants in Various Osteotomy Techniques: Three-Dimensional Finite Element Study.

Conventional osteotomy techniques can, in some cases, induce higher stress on bone during implant insertion as a result of higher torque. The aim of the present study was to evaluate and compare the stress exerted on the underlying osseous tissues during the insertion of a tapered implant using different osteotomy techniques through a dynamic finite element analysis which has been widely applied to study biomedical problems through computer-aided software. In three different types of osteotomy techniques, namely conventional (B1), bone tap (B2), and countersink (B3), five models and implants designed per technique were prepared, implant insertion was simulated, and stress exerted by the implant during each was evaluated. Comparison of stress scores on the cortical and cancellous bone at different time points and time intervals from initiation of insertion to the final placement of the implant was made. There was a highly statistically significant difference between B1 and B2 (p = 0.0001) and B2 and B3 (p = 0.0001) groups. In contrast, there was no statistically significant difference in the stress scores between B1 and B3 (p = 0.3080) groups at all time points of implant placement. Overall, a highly significant difference was observed between the stresses exerted in each technique. Within the limitations of our study, bone tap significantly exerted lesser stresses on the entire bone than conventional and countersink type of osteotomy procedures. Considering the stress distribution at the crestal region, the countersink showed lower values in comparison to others.