Mouth Gags

What Are Mouth Gags?

Mouth gags are surgical instruments placed between the upper and lower jaw to keep the mouth open during oral and throat procedures. Despite their long history, they remain a staple in operating rooms worldwide.

The History of Mouth Gags

Early Beginnings

The earliest documented use of medical mouth gags dates back to the late 1500s. In 1714, Lorenz Heister, a military surgeon, developed a screw-like device to open a patient's mouth in cases of trismus, a condition caused by tetanus where the jaw muscles become so tight that patients can't open their mouths. This device, known as the Heister gag, served as a prototype for future models and continued to be used, with minor modifications, until 1930.

Anesthesia and Increased Demand

The advent of general anesthesia in 1846 significantly increased the demand for jaw-opening devices. Anesthesia required unobstructed access to the endotracheal tube, and mouth gags facilitated this by keeping the mouth open and fixed during surgery. Over time, surgeons identified the characteristics of an ideal mouth gag, guiding future design improvements.

Characteristics of an Ideal Mouth Gag

These characteristics can be summarized as:

• Providing adequate exposure to all parts of the oral cavity to perform surgery.
• Being compatible with different shapes and sizes of the oral cavity.
• Facilitating safe anesthesia administration via the endotracheal tube without kinking or putting pressure on it.
• Ensuring secure fixation to prevent slippage and subsequent tissue trauma or damage.

Based on these requirements, early tools were modified to allow the jaws to be "jacked" open and to hold an anesthetic tube securely in the tongue depressor. They were also designed in several parts for easier sterilization and more freedom of use. Eventually, they started to resemble the mouth gags we are familiar with today.

Modern Variations

Since Heister's design, a wide variety of mouth gags, with or without tongue depressors or plates, single-sided or double-sided, have been invented and distributed. Let's take a look at some of the most common varieties of mouth gags that are still frequently used.

Different Types of Mouth Gags

1. Davis Gag

In 1910, anesthesiologist S. Griffith Davis modified an earlier Hartman gag for use in tonsillectomies. Henry Boyle eventually popularized this variant, leading to it being better known as the Boyle or Boyle-Davis gag. It consists of a frame that joins a handle with a selection of tongue depressors called blades. The paddle of the depressor holds the patient's tongue and lower jaw, while rubber-lined extensions at the top of the frame support the patient's upper teeth. Despite at least 20 further modifications from the 1920s through the 1990s, the original design continues to be made by manufacturers and is still in common use among surgeons and medical practitioners.

2. Denhardt Mouth Gag

Introduced in 1887 by Dr. Charles Denhardt, this instrument was a modification of O'Dwyer's gag, which was easily dislodged during surgery. The arms of the Denhardt gag curve sharply at the point they exit the mouth, ensuring that the handles are located close to the side of the face. This design allows an assistant to easily keep the gag and the patient's head stable. This improvement cemented the use of the Denhardt gag for decades, and future modifications, such as the Denhardt–Hoefert Mouth Gag, have only improved on this reliable and time-tested instrument.

3. Jennings Mouth Gag

Introduced in 1914 by St. Louis physician John Ellis Jennings, this gag is a modification of the earlier Whitehead gag. The built-in tongue depressor of the older gag was removed and simplified for easier adjustment. The Jennings Mouth Gag is operated via a single ratchet that can be controlled with one hand using the finger and thumb. Unlike earlier designs, which featured two spring-loaded ratchets, this variation has greatly increased the instrument’s ease of handling. The Jennings gag’s functional form and ease of use have kept it in production today, and it is widely used.

4. Doyen-Jansen Mouth Gag With Grip Lock

The Doyen-Jansen is a variation on the Doyen Gag, an early design that simply held the mouth wide open but required stitching the tongue to maintain an airway and clear view for the surgeon. The Doyen-Jansen variety offers improved handling with its Grip-Lock mechanism that holds the blades in place at the desired width while conducting the procedure and allows a strong hold over the instruments. Its ratchet mechanism keeps the mouth open during surgery, reducing tissue damage, and its curved front design allows for atraumatic handling inside the mouth. These advantages, along with Doyen-Jansen’s enduring and functional design, mean it is still a regular part of many surgical setups today.

Conclusion

Mouth gags have evolved significantly since their inception in the late 1500s, driven by advancements in medical science and the specific needs of surgeons. From the Heister gag to the modern Doyen-Jansen, each iteration has aimed to improve the safety and efficiency of oral and throat procedures. Understanding the history and development of these essential surgical tools highlights the continuous innovation in medical technology, ensuring better patient outcomes and more efficient surgical practices.