EMG-Guided Injection of Botulinum Toxin for R-CPD

Background: What Is R-CPD?

R-CPD (Retrograde Cricopharyngeus Dysfunction) is a disorder of the upper esophageal sphincter, a ring-shaped muscle in the lower throat that acts as a valve. It opens briefly to allow swallowing or, in the reverse direction, to permit burping or vomiting. 

In persons with R-CPD, this muscle fails to open in the reverse direction. The result is not only the inability to burp, but almost universally, gurgling noises, bloating, and excessive flatulence. 

Common but less universal symptoms include painful hiccups, nausea after eating, a feeling of inability to fill the lungs fully when bloated, hypersalivation, constipation, and even flushing and rapid heartbeat when very bloated.

Standard of Care

Treatment typically involves injecting botulinum toxin (“Botox”) into the cricopharyngeus muscle (upper esophageal sphincter). This can be done under brief general anesthesia through the mouth in an outpatient OR, or in the office via EMG-guided injection through the neck while the patient sits upright in an examining chair. The latter method is the subject of this paper. 

EMG-Guided Injection: Step-by-Step

1. Initial Preparation: A tiny cosmetic needle injects local anesthetic into three neck skin sites (two lateral, one midline). You’ll feel a small sting with each of the three skin injections. After the third (central) injection, the physician will say, “OK, you are going to cough right now.” At that moment, you may feel a brief gush of fluid in your throat that triggers a cough. Many patients describe the taste as very bitter.
2. Botox Delivery (~5 Minutes Later): EKG-style pads are placed on your neck and connected to a small EMG device. The physician uses a Teflon-coated EMG needle to locate the muscle. The injection takes about 15–20 seconds.
3. Potential Discomfort: Sharp sensation from the needle; Deep pressure or referred pain to the back of the neck/shoulder; Patients most often rate discomfort between 3–4 on a 10-point scale, with less common reports up to 7–8.5, rapidly “fading” after injection is complete.
4. Success Rate: Very high. As of April 2025, over a hundred EMG-guided cases, only one was a complete miss, and that was among the earliest cases.

After Your EMG Injection for R-CPD

You should have very little pain following the procedure— even if it was somewhat uncomfortable during the 90 seconds of the injection itself. Afterward, carry on with your normal activities: eat, shop, drive, and resume life as usual.

Two Predictable Effects:

Burping (the goal of the procedure!)

• • Burping begins for everyone.
  • Onset is usually 1–5 days after the injection (sometimes as early as 12 hours).
  • Burps start small (“micro-burps”) and grow stronger over days to weeks.

Slow Swallow (temporary, expected)

• • Appears after micro-burps begin, not immediately following the injection.
  • Caused by the “botoxed” muscle being temporarily limp.
  • Sensation may feel like food is “stuck,” but it is safely in the correct place—just “hanging” within the limp muscle
  • How to manage “slow swallow”: keep liquid in your non-dominant hand while eating solid foods. Take small to medium bites and chew well (to a count of 15+). Swallow with a sip of liquid added to what you are about to swallow, or with a cup at your lips so liquid sip follows immediately on the tail of the swallow with no “space” between. Avoid large bites or inadequate chewing.
  • Duration of “slow swallow” is typically 1–3 weeks, sometimes longer. Many stop noticing or caring about the sensation, once they experience this for a few days. If anxious, softer foods (soups, oatmeal, smoothies) may help for a short time.

Three Uncommon but Possible (Temporary) Side Effects:

Noisy Breathing (Vocal Sound)

• • May occur with exertion (increased velocity of inspiratory airflow) or during sleep (due to relaxation of muscle tone).
  • Not dangerous, but can be bothersome for bed partners.
  • Caused by minor diffusion of botox into vocal cord muscles.

Voice Change

• • Rare; usually noticed mainly by the patient (e.g., less ability to project voice).
  • A few singers have noted difficulty with upper range.
  • Always temporary.

Laryngospasm (very rare)

• • Feels like throat “closes off” briefly, due to, by analogy, a “charleyhorse” of the vocal cords.
  • Often triggered by large/fast bites. This seems to be the group most affected. 
  • Frightening, but not dangerous.
  • Learn how to manage by practicing “straw breathing.”

Be Sure to Practice Once Burping Is Underway:

Buy a case of non-sugary sparkling water and practice daily:

1. 1. Drink about a quarter can, try to burp it up.
   2. Repeat with the next quarter.
   3. Don’t overload—find your comfortable amount.

What You’re Trying to Accomplish with Your Practicing

First, discover a maneuver, or “fidget” to “release” the burps. People often use subtle actions: head turn, chin tuck, gentle yawn (lowering the larynx). Think of it as inviting the burp (“yoga”), not forcing it (“powerlifting”).

1. 1. First week or two: “pure botox” burps.
   2. Then: “botox + you” burps (you’ve figured out how to release the burp a split second earlier than it would have if you had not found the “release” maneuver).
   3. Finally: “pure you” burps.

Summary

Expect burps in 1-5 days, a temporary slow swallow phenomenon, and—rarely—minor temporary side effects. In the early week(s), adapt how you swallow, find the “release” and practice burping, and review the laryngospasm video just in case.