The exoscalpel is a precision surgical instrument, and the medical version of a laser scalpel. It employs laser beams to make an incision in skin or other tissue. After completion of surgery, a dermal regenerator can be used to repair the cut tissue.
An exoscalpel was used during the surgery to replace Lieutenant Worf's spinal column in 2368. (TNG: "Ethics")
Exoscalpels have been seen in a wide variety of sizes and configurations. The exoscalpel prop depicted has been used in a variety of different applications, such as that of a scanner device in TNG: "The Host".