What Is a Trocar? A Plain-Language Guide

Last verified: October 6, 2026. A trocar is a surgical instrument used to create a small opening through the body wall and, together with a hollow tube called a cannula, to keep that opening available as a working channel. It is the doorway through which cameras and slender instruments enter the body during laparoscopic and other minimally invasive procedures. This guide explains what a trocar is, what it is made of, the main types, how it differs from related tools, and what research administrators, procurement staff, and operating-room managers should know. It is general information, not clinical or safety training; follow your institution’s procedures and the manufacturer’s instructions.

What Is a Trocar?

The word “trocar” strictly refers to a sharp or blunt-tipped rod, called the obturator, that is used to pierce or push through tissue. In everyday surgical speech, though, the word usually means the whole assembly: the obturator inside a hollow sleeve, the cannula. Once the obturator has made its way through the body wall, it is withdrawn, and the cannula stays in place as a tube through which instruments, a camera, or gas can pass. Many modern products are sold and described as “trocars” or “trocar-cannula systems” or simply “ports.” Those labels overlap in practice, which can make catalog searching confusing.

A trocar is not a cutting or treating instrument in itself. Its job is access. It defines where and how other instruments get in, protects the opening from damage as instruments are passed back and forth, and, in many surgeries, helps keep the working space sealed so that it stays inflated.

Why It Exists: The Problem a Trocar Solves

Traditional open surgery uses a single large incision so the surgeon can see and reach the target directly. Minimally invasive surgery instead uses several small openings, each just big enough for a camera or a slim instrument. That approach is meant to reduce tissue disruption and, for many procedures, shorten recovery. But small openings create a practical problem: instruments pass through them dozens of times during an operation, and repeated passage through bare tissue would be awkward and could damage the edges of the opening. A cannula holds the channel open and protects it, and a valve at its outer end keeps gas from escaping. The trocar is how that channel is created in the first place.

The Main Parts of a Trocar System

• Obturator — the inner rod that passes through tissue. Tip designs vary: some are pointed, some are bladed, some are blunt, and some are optical, which means they have a clear tip that lets a camera show the layers of tissue as the device advances.
• Cannula — the hollow tube that remains in the body wall after the obturator is removed. It comes in different diameters to match the instruments that will pass through it.
• Seal or valve assembly — a set of gaskets or flaps at the top of the cannula that let instruments in and out while keeping gas from escaping.
• Insufflation port — a stopcock or side connection, on at least one port in many procedures, through which gas enters the body cavity to create working space.
• Stabilizing features — threads, ribs, or balloon collars on the outside of the cannula that help keep it from slipping in or out.
• Safety shield (on some designs) — a spring-loaded guard that covers a bladed tip once the tissue has been passed, intended to reduce the risk of injury to structures beneath.

Types of Trocars

By how the tip works

• Bladed trocars have a cutting tip that divides tissue as it advances.
• Bladeless (dilating) trocars have a tapered tip that separates tissue fibers instead of cutting them, which some surgeons prefer because the resulting opening may close more neatly.
• Optical trocars allow a camera to be placed inside the obturator so that the surgeon can see each tissue layer during placement.
• Blunt-tip trocars are used where the opening has already been made by another technique, to hold it open and provide a sealed port.

By how it is made and reused

• Single-use (disposable) trocars are usually plastic, and they are discarded after one patient.
• Reusable trocars are usually metal or durable polymer, and are cleaned and sterilized between patients, with the seals often replaced regularly.

By size

Cannulas are made in a range of diameters. Small ports are used for slender instruments or small cameras, and larger ports allow bigger tools, such as stapling devices, or the removal of tissue specimens. Exact sizing conventions vary by manufacturer, so match the trocar to the instrument by checking the product documentation rather than assuming equivalence.

Why Port Design Details Matter

Small design choices have large practical effects. The seal has to tolerate repeated insertion of instruments of different sizes without leaking, which is why some ports include a reducer or a multi-layer valve. The length of the cannula has to suit the thickness of the body wall, since a port that is too short can slip out and one that is too long can limit instrument movement. The outer surface affects how firmly the port stays put. The handle or housing affects how comfortably it can be held and how easily instruments can be exchanged. Surgeons and operating-room staff notice these differences quickly, and that is why trial evaluations, rather than catalog descriptions alone, are a common step before a hospital standardizes on a port line. For buyers, it means that a lower-priced trocar that frequently leaks or dislodges can cost more in wasted time and replacements than its price suggests.

Beyond Laparoscopy

Although the word is most closely associated with laparoscopic abdominal surgery, trocar-style access is used in other places as well. Chest (thoracoscopic) procedures use ports through the rib spaces. Some orthopedic and urologic procedures use access sleeves of similar design. In veterinary and research settings, smaller trocars are used in animal surgery. A different, older sense of “trocar” also exists, referring to a sharp-pointed instrument used to drain fluid from a body cavity, which is a distinct product and not what this page mainly covers.

How a Trocar Differs from Related Equipment

• Trocar vs. cannula — the cannula is the tube that stays; the trocar, strictly, is the piercing obturator that places it. In daily use the terms are often combined.
• Trocar vs. needle or scalpel — a scalpel makes an incision for open access or to create a small skin entry before a trocar is placed. A trocar goes further, creating a sealed, reusable channel rather than just an opening.
• Trocar vs. laparoscope — the laparoscope is the camera instrument that passes through a port; the trocar is the port. They work as a pair.
• Trocar vs. retractor — a surgical retractor holds an incision open or moves tissue aside; a trocar provides a small, sealed channel for instruments.

Practical Relevance for Research Administration and Procurement

• High-volume consumable. A single laparoscopic case may use several ports, so trocars scale directly with case volume. Small differences in unit cost add up quickly.
• Standardization. Fewer trocar types across the operating room simplify inventory, but surgeons may have strong preferences, so purchasing committees often balance both.
• Compatibility. Seals and sizes must match the instruments in use, and not every instrument fits every port, so check with the surgical teams before changing suppliers.
• Single-use versus reusable. Reusable trocars shift cost to cleaning and sterilization, and require a reprocessing workflow. See medical device reprocessing. Total cost per case, not purchase price, is the useful comparison.
• Sharps and safety. Bladed tips are sharps, so disposal planning belongs in the purchase decision.
• Research. Studies of surgical technique or devices should record the port type and size, because these can influence outcomes and reproducibility.

Frequently Asked Questions

What is a trocar used for?

It is used to create a small access channel through the body wall so that a camera and slim instruments can be inserted during minimally invasive surgery, and to keep that channel open and sealed during the procedure.

Is a trocar the same as a cannula?

Not strictly. The trocar is the piercing rod (the obturator), and the cannula is the hollow sleeve that remains afterward. Many products combine the two and are sold as a single trocar system, so people often use the terms interchangeably.

What does a bladeless trocar do differently?

It spreads tissue fibers apart with a tapered tip instead of cutting them. Which design is preferred is a clinical decision that depends on the procedure and the surgeon.

Are trocars single-use?

Many are, particularly plastic designs, but reusable metal versions are also available. The choice depends on volume, reprocessing capacity, and facility policy.

Why does a trocar have a valve?

The valve lets instruments pass in and out while keeping gas inside the body cavity. Without it, the working space created by gas inflation would collapse every time an instrument was changed.

How many trocars are used in one operation?

It depends on the operation. Some procedures use only a few ports, and others use more. The surgeon decides based on the procedure and the patient.