Written and maintained by CASRAI Editorial Board
Last updated
General product information only, not medical advice and not a procedure guide.
Short answer
A surgical burr (also spelled “bur”) is a rotating cutting tip that a drill uses to cut, shape or remove bone. In US regulation, cranial burrs are not classified by their shape: 21 CFR 882.4300, 882.4305 and 882.4310 group “drills, burrs, trephines, and their accessories” by whether the instrument is manual, powered with a clutch, or powered without one. All three are Class II.
Definition and scope
This page covers burrs used on the skull and other bone, the neurosurgical sense of the word. Dental burs are a separate product family and are not covered here. The FDA regulation describes manual cranial drills, burrs, trephines and their accessories as “bone cutting and drilling instruments that are used without a power source on a patient’s skull” (21 CFR 882.4300, checked 2026-10-31). A burr is therefore a cutting tip or accessory used with a drill, not a stand-alone device category.
How burrs are described
A patent describing surgical burs (EP3344164B1, checked 2026-10-31) explains that burs need sharp, durable cutting edges to dissect, cut or shape bone. Those edges are formed by flutes. Each flute lies between lands and has a chip space and one or more rake surfaces at a cutting edge, and the flutes help move bone chips out of the cutting path. A bur can have any appropriate number of flutes. The patent describes one design and is not a standard, but its vocabulary is a useful reading aid for catalog listings.
| Term | Meaning in the patent text |
|---|---|
| Flute | The groove that defines a cutting edge and carries chips away from the cutting path |
| Land | The surface between flutes |
| Rake surface | The surface at a cutting edge, one or more per flute |
| Chip space | Room within the flute for bone chips |
Types and shapes
Round burr
The patent lists external shapes “such as a ball, a cylindrical, an oval, or other generally known shape”. A round burr is the ball shape.
Matchstick burr
The same patent says one design is called a “match head”, “neuro” or “matchstick” design, with two convex lands and two flutes (a second embodiment has three flutes). So “matchstick burr” names a design family, not a regulatory class.
Trephine bur
Regulation names burrs and trephines together. The CASRAI guide to the trephine covers that instrument and its FDA classification separately.
Midas Rex burrs
Midas Rex is a brand name, not a device type, and the searcher usually means burrs used with that brand of drill. See the Midas Rex drill guide.
Manual, powered compound and powered simple: the classification cross-walk
The three regulations differ in power and in a clutch. Per 21 CFR 882.4305, a powered compound instrument “employ[s] a clutch mechanism to disengage the tip of the instrument after penetrating the skull to prevent plunging of the tip into the brain.” A powered simple instrument, per 21 CFR 882.4310, is used with a power source but has no such clutch.
| FDA product code | Name in openFDA | Regulation | Class |
|---|---|---|---|
| HBG | Drills, Burrs, Trephines & Accessories (Manual) | 21 CFR 882.4300 | 2 |
| HBF | Drills, Burrs, Trephines & Accessories (Compound, Powered) | 21 CFR 882.4305 | 2 |
| HBE | Drills, Burrs, Trephines & Accessories (Simple, Powered) | 21 CFR 882.4310 | 2 |
Source: Cornell LII text of each regulation and the openFDA classification API, both checked 2026-10-31 (openFDA states its data is not for medical decisions).
Where it matters for labs, clinics and supply decisions
Because the regulation covers burrs together with drills and trephines, the same word “burr” can appear under three product codes. The shape of a burr (round, matchstick, oval) does not decide the code; the power source and the clutch of the system do. For the instrument families around burrs, see orthopedic surgical instruments, ENT surgical instruments and the manual bone file.
Common misunderstandings
“Bur” and “burr” are two different tools
They are spelling variants. The regulation says “burrs”; the patent says “burs”. Both mean the same kind of cutting tip.
A burr is a drill
The regulation lists “drills, burrs, trephines, and their accessories” as separate items under one heading. The burr is the cutting tip that the drill drives.
Every burr falls under 882.43xx
No. Those regulations concern cranial instruments. A powered corneal burr, for example, is covered in the Alger brush guide under an ophthalmic regulation.
FAQ
What is a surgical burr?
A rotating cutting tip on a drill, used on bone. FDA groups cranial burrs with drills and trephines in 21 CFR 882.4300 to 882.4310, all Class II.
What is a matchstick burr?
A design the patent EP3344164B1 calls “match head”, “neuro” or “matchstick”: two convex lands and two flutes in its main embodiment.
Is it “bur” or “burr”?
Both spellings are used for the same kind of cutting tip. The regulation says “burrs”; the patent says “burs”.
What is a round burr?
A burr with a ball-shaped outer profile, one of the shapes the patent lists alongside cylindrical and oval.
Are Midas Rex burrs a separate FDA category?
No. Midas Rex is a brand; the regulatory category depends on whether the system is manual, powered compound or powered simple.
Sources
- 21 CFR 882.4300, 882.4305 and 882.4310, Cornell Legal Information Institute: https://www.law.cornell.edu/cfr/text/21/882.4300 (also 882.4305 and 882.4310). Checked 2026-10-31.
- openFDA device classification API, product codes HBE, HBF, HBG: https://api.fda.gov/device/classification.json?search=product_code:HBE. Database updated 2026-10-19, checked 2026-10-31.
- EP3344164B1 “Surgical burs”, Google Patents: https://patents.google.com/patent/EP3344164B1/en. Checked 2026-10-31. A patent describes one design and is not a standard.
