“Nut-to-Nut” or Not?

My first surgical procedure on the equine-specialty rotation was a castration of a one year old quarter horse. The castration is the most common “field surgery” performed by mobile equine practitioners, and also the subject of the majority of lawsuits against equine veterinarians. 

As the subject of most lawsuits against equine practitioners, there are definitely serious and life-threatening complications that can arise…sometimes due to doctor negligence, sometimes through no fault of the veterinarian. This was the basis for our morning pre-operative doom-and-gloom session. Bowel perforation, emasculation of the penis, emasculation of the small intestines, ligation mishaps, improper use of the emasculators…the stuff veterinary students nightmares are made of.

Helpful, informative, productive- the review was. Confidence booster, it was not.

Today I performed my first “partial” castration. By “partial” I am referring to fact that I removed one of two testicles. Unfortunately, at a vet school that does not have a teaching budget, students ultimately depend on what particular cases walk through the door. This rotation, with ten students, has over twice the normal number of students. Inevitably, hands-on experience becomes diluted among so many eager individuals. Today, there were only two horses in for castration, which resulted in four students each removing a testicle from either of the two horses.

Our patient, a timid yearling quarter horse, was pre-med, induced and placed in dorsal recumbency. 30 ml of lidocaine were injected into the body of each testicle before performing a sterile prep of the scrotum and surrounding surgical region. My classmate went first, acting as the “surgeon” and I her assistant. She worked fast…like this was the Great Race of procedures. When she couldn’t produce the testicle from the scrotum, I extended her incision with the scalpel. Originally intended to be the closed technique, this was changed to an open technique after vigorous stripping of the fascia and tissue around the tunic-encased testicle. She placed two transfixing ligatures around the spermatic cord and cremaster muscle. Collectively ligating the muscle and cord would prove less than ideal later on in the surgery. The emasculator, the crushing and cutting instrument, was positioned distal to the ligatures. She closed the emasculator around the cord and muscle. Hardly a minute later, she looked at me suddenly.

“I put the emasculators on wrong.” Dead silence. “I put them on backwards. Not nut-to-nut.” She was explaining this as I started looking over orientation of the instrument. The popular, albeit vulgar, phrase “nut-to-nut” pertains to the proper orientation and application of the emasculator tool. One side of the instrument has a nut positioned near the hinge, The tool is positioned so that the nut on the instrument is on the side closest to the testicle that is about to be removed. This is important because the crushing plate must be closer to the patient than the cutting blade. Crushing the tissue and vasculature helps reduce bleeding and facilitate clotting. Without fail, simply transecting the vasculature of the testicular would lead to excessive hemorrhage.


But, wisely, my classmate had placed two ligatures around the cord and muscle. The point of ligation is to stop bleeding, regardless of the emasculator orientation. I reassured my classmate that the ligatures would prevent bleeding if the emascular was incorrectly placed. Everyone was still silent, though cumulatively I know blood pressures were on the rise.

The resident came to investigate the situation. He abruptly turned to my classmate and said:”Do you know what a nut is?”

Caught off guard by his question, my brain started cycling through the least likely of definitions.He turned to me “Do you guys know what a nut is?” It remained dead quiet.

Wanting the awkward Q&A session to pass, I said “Yes.” Then I motioned to the castration site and said plainly. “Well, we just removed one and it wasn’t because of a lucky guess.”

The resident looked puzzled. My classmate looked puzzled. But from behind me, several classmates, technicians and a surgeon were laughing. Someone said “Wrong kind of nut!” I felt flushed, and I knew I was turning bright red from embarassment. What a crude response! I can’t believe I can sound so classy at times. Just writing about it, I’ve already buried my face in my hands twice!

The resident pointed to the emasculator. “That kind of nut.” He was shaking his head when he said something clever along the lines of: “If you knew what that kind of nut was, you’d also know that you placed your emasculators correctly.

I was still blushing something awful when my classmate removed the emasculator (stays clamped for 2 minutes or more). Interestingly, the cremaster muscle had contracted after it was transected…which lead to slack in the ligatures and rendered them useless. This is the reason why the cremaster muscle is not ligated with the spermatic cord.  But with no active bleeding, the ligatures were removed and the stump left as is.

I performed the second half of the castration using a closed technique and with an abundance of dissatisfaction in myself (I will expand upon this in the next post). But, importantly, recovery from surgery was uneventful. The procedure ended up being 40 minutes long. Our patient did well overnight and this morning he was bright, alert and hungry. I’m pretty sure he’s ready to be out of the teaching hospital, and in less than 48 hours he’ll be back at home.