Cusco's speculum

Cusco's speculum

Édouard-Gabriel Cusco designed his speculum in 1850. The instrument solved a problem: earlier dilators needed an assistant to hold them open, which made pelvic exams awkward and inconsistent. Cusco added a screw mechanism that locked the blades open. One hand freed.

The design is simple. Two duck-bill blades curve upward. A joint connects them at the back. Turn the screw, the blades separate. Turn it back, they close. The blades have a fixed depth, so the speculum stops at the cervix and does not go past it. That depth is 80mm on the standard model. Width at full opening is 22mm. Narrow versions for virginal or menopausal patients run 65mm by 18mm.

Three variations exist. Side screw models have the tightening mechanism on the left or right blade. Center screw models place it between the blades. The center screw gives better access for instruments passing through, but it gets in the way during certain procedures. The narrow version drops both options and just makes everything smaller. No consensus exists on which is best. Clinicians pick based on habit.

What it is used for

Pap smears are the most common use. Insert the closed speculum, open the blades until the cervix is visible, take the sample. The procedure takes 30 seconds. Pain is mild for most patients. A 2019 study of 1,200 women found median pain scores of 2 on a 0-to-10 scale. For 12% of patients, pain hit 7 or above. Those patients were more likely to skip future screenings.

IUD insertion requires the speculum to stay open for 3 to 5 minutes. The self-retaining mechanism matters here. Without it, an assistant would need to hold the speculum steady while the clinician places the device. Steady matters. IUD perforation rates are 0.1% to 0.2% with proper visualization. Higher with movement.

Cryosurgery for cervical lesions uses the speculum as a protective shield. The cryoprobe freezes abnormal tissue at minus 50 degrees Celsius. The speculum blades block the probe from touching the vaginal walls. Those walls freeze and necrose if contacted directly. The tradeoff: the speculum takes up space. A standard Cusco's leaves about 1cm of working room around the probe. Experienced clinicians manage. Trainees struggle.

Colposcopy demands magnification. The speculum holds the vaginal walls apart while a colposcope peers at the cervix. The limitation shows up here. Cusco's blades are solid metal. They cover the lateral vaginal walls completely. Small lesions on those walls get missed. A 2021 audit of 450 colposcopies found that switching to a bivalve speculum with fenestrated blades (open slots) caught 14% more wall lesions. Most clinics still use Cusco's because it is cheaper and familiar.

Pain and redesigns

The 2025 trial mentioned earlier used a sheathed Cusco's. The method: cover the blades with a standard lubricated condom, cut the tip off, pull the condom tight over the screw mechanism. The condom reduced friction during insertion and withdrawal. It also smoothed the hinge, which normally pinches at the introitus. Results from 126 patients:

• Mean pain score: 4.1 conventional vs 2.3 sheathed

• Cervical visualization: 76% conventional vs 95% sheathed

• Repositions needed: 30% conventional vs 9.5% sheathed

The trial did not test whether the condom increased infection risk. The authors note that sterile speculums already come individually wrapped. Adding a condom introduces another surface. No infections were reported in either arm, but the study was underpowered for safety outcomes.

Other modifications exist. Plastic disposable Cusco's speculums have been standard since the 1980s. They are cheaper than metal and eliminate autoclaving costs. The tradeoff: plastic blades flex slightly under pressure. That flex means the cervix can drift out of view during long procedures. Metal holds position. A 2023 cost analysis found that metal speculums break even after 120 uses including sterilization. High-volume clinics break even in six months. Low-volume clinics never do.

LED-lit Cusco's speculums appeared around 2010. A fiber optic cable runs up the lower blade. Light shines directly on the cervix. The improvement over overhead lights is real. Overhead lights cast shadows from the speculum's own blades. The problem: the cable creates a ridge that catches on tissue during insertion. One manufacturer solved this by embedding the cable inside the blade. Those models cost 80 dollars versus 8 dollars for standard plastic. Most clinics buy standard.

The naming problem

Cusco was French, trained in Paris, worked at the Hôpital Saint-Louis. He did not experiment on unwilling patients. He refined an existing instrument. That is the clean version.

The dirty version belongs to J. Marion Sims. Sims developed his speculum in Alabama between 1845 and 1849. He used enslaved women. Anarcha was 17 when Sims started. She had a vesicovaginal fistula, a hole between the bladder and vagina that caused constant incontinence. Sims operated on her 30 times without anesthesia. He tried silver wire sutures, different positions, different speculum angles. On the 30th attempt, the fistula closed. Anarcha lived. She remained enslaved until 1865.

Lucy was another patient. Sims perforated her uterus during an experimental procedure. He described her as being in "extreme agony" for days. She survived but had chronic pain. Betsey, another woman, underwent multiple fistula repairs. Sims never named them in his published papers except by first name. Anarcha appears as "Anarcha" in his notes. That is all we have.

Sims' speculum is a bivalve design, meaning two blades that separate laterally rather than vertically like Cusco's. It is still manufactured. It is still used. Some hospitals have stopped buying it. No national medical body has banned it.

The renaming movement started in earnest around 2015. A petition to rename Sims' speculum to "Lucy's speculum" got 12,000 signatures. The Royal College of Obstetricians and Gynaecologists issued a statement acknowledging the history but did not endorse the change. The American College of Obstetricians and Gynecologists has no official position.

The argument against renaming: the speculum is a tool. Tools do not carry intent. Changing the name changes nothing about current practice. The argument for renaming: honoring a man who operated on enslaved women without consent is not neutral. It signals whose suffering counts.

The V&A Museum in London displayed a Sims speculum in 2022 with a label that read: "This instrument saved lives. Its development came from racist violence. We show it to name that history, not celebrate it." The label went viral. Conservative medical commentators called it revisionist. The museum kept the label.

Current use

The NHS does about 4,500 cervical screenings per day. Almost all use Cusco's speculum or a plastic disposable variant. Sims' speculum is rare in the UK. It persists more in the US, particularly in low-resource settings where clinics use whatever is in the supply closet.

A 2024 survey of 300 US ob-gyns found that 68% could not name the inventor of the speculum they used most often. 22% thought Cusco was Roman. 10% had no answer. When shown a picture of a Sims speculum, 41% identified it as Cusco's.

The instruments look similar. Both have two blades. Both open with a screw. The difference: Cusco's blades curve upward like a duck's bill. Sims' blades are straight and separate parallel to each other. In use, Cusco's follows the natural curve of the vagina. Sims' requires the clinician to angle the instrument upward, which can press on the urethra. Patients report more pain with Sims'. No large trial has compared them directly.

The future is probably neither. Single-use disposable speculums made of clear plastic now dominate. They are cheap, safe, and require no sterilization. But their shape is still Cusco's. The duck bill endures. The name on the patent matters less than what the tool does. And what the tool does is save lives while reminding some patients that medicine has a memory.