Musculoskeletal Procedures, Points for Trainees.

Knee arthrogram

Some general points on doing musculoskeletal procedures, which are meant for new radiology residents/fellows.

Please, remember that most of these procedures, especially the out-patient ones will be elective. As such, there is no rush to get everything done “as quickly as possible.” The goal should be patient comfort and pleasant patient experience.

Consent is a very important part of this process. Explain what procedure will be performed. What are its benefits. Are there any alternatives? What are the potential complications/risks. Most patients had at least some experience with a dental procedure. When explaining risks such bleeding, infection, damage to structures nearby, it is helpful to mention that those are very similar to any other procedures including dental work.

This nicely leads to discussion of some “burning” sensation when local anesthetic is administered. Again, similar to what they may have felt in a dentist office.

Calm, friendly discussion of these topics usually eases patient anxiety about the procedure, as they realize that they may have gone through an experience somewhat similar to the one immediately ahead.

Time-outs are now a near universal occurrence in all kinds of health care settings. The awkwardness of someone trying to check patient’s ID band on an awake patient can be at least partially minimized by asking patient to participate in this process. For example: “Let’s do a safety check. Please give us your full name and date birth. What procedure are we doing? What are your allergies?” And most importantly for musculoskeletal procedures: “What side are we working on?”

Marking the site.

Do not forget that you have extensive training in anatomy and regular physical examination. With time and experience, you will be able to place your marker on patient skin without fluoro, then tap fluoro pedal to check where you are, and in many cases, you will not have to adjust anything.

Do not be a “lead foot” on the fluoro button. Just because fluoro is available, it does not mean that you have to use it all the time.

Remember distance, time and collimation can usually be adjusted according to good ALARA principles. Move patient/table as close to the image intensifier as practical. Briefly tap fluoro button and release as soon as you get an image. Do not fluoro as you move image intensifier trying to find a joint. This applies to time prior to marking as well. Look at the center of image intensifier – you can usually place it right over your marker without fluoroscopy. Make sure that your marked spot is in the center or at least close to the center of the field of view to eliminate parallax problems that you may encounter later. Collimate, collimate, collimate.

Hip No Collimation
Fluoroscopic image of the hip with no collimation. Note uneven radiographic penetration. Although not perfectly in the center, the marker is appropriately close to the center of the image.
Hip Collimation
Fluoroscopic digitally modified image of the hip shows better FOV that can be achieved with collimation.

Cleaning and draping.

By the time a person starts radiology residency, not much teaching needs to be done about sterile technique, in most cases. More of a psychology point rather than teaching point here, but if you are not sure if you touched something non-sterile, just change your gloves. No one is judging.

Local anesthetic.

Look up maximum Lidocaine dose and do some math on how much you usually use. Do you really need to use everything that technologist gave you from a 10 cc vial? Most of the sensory nerve fibers are in the skin. The most important step here is to make a nice wheal during intradernal injection. Use a very thin needle: 25G, or some places even have 27G needles. You only need a small amount, usually 2-3 cc to anesthetize subcutaneous tissues. You can always put more later if needed. Do not be shy to indent the skin and inject some Lidocaine close to the joint capsule. Joint capsule also has nerve fibers, and about half of the patients will feel an arthrogram or injection needle going through it.

Adjusting the Needle

If your needle is in the center of the field of view, like it should be, you want the hub of the needle to be right over it’s tip. Insert the needle just enough to keep it steady and check with fluoro. The best time to adjust trajectory is before a soft tissue tract is made by the needle. For patients with large amount of soft tissues who require longer needles, go slow and check every few centimeters to adjust the course of the needle if needed.

Think about the anatomy of the joint you are dealing with. For example, a needle tip projecting over glenoid rim on frontal view may be inside or outside of the joint as glenoid is concave. If you are having hard time, redirecting toward the humeral head would usually solve the problem. If the needle tip is projecting over the humeral head, there is nothing there beside humeral head cartilage, synovium and joint capsule.

Rotator Interval Approach
Fluoroscopic image of the shoulder during rotator interval approach contrast injection. What happened here? Notice the needle is a bit too high compare to the center of the FOV. Small amount of contrast ended up in deltoid muscle or soft tissues. After the needle was advanced further, contrast flowed into glenohumeral joint.

Mixing your Solutions.

Think about what you use and what toxicity/side effects various solutions may have. What are the effects of placing various solutions in unintended spaces? For example, if all you want to do is check your needle placement, use Lidocaine syringe first. If you are not in the joint space, no contrast is administered into surrounding soft tissues and soft tissues get a little more Lidocaine, which increases patient comfort. Once your are comfortable that the needle is in the joint, then injected a drop of Iodine solution under brief continuous fluoro. You will see a whiff of contrast diffusing into the joint space away from the needle. Although most of the toxicities are theoretical in the majority of real life scenarios, there is no reason to use up 5 cc of iodinated contrast, where a drop or two is all you need. If the final objective is to place Gadolinium into the joint, there are pros and cons of mixing Gadolinium with Iodine. Some radiologists mix Gadolinuim with saline only, others add a small amount of iodinated contrast to see joint distention as they inject.

Final Thoughts.

The difference between excellent patient experience and “I don’t want to ever come back to this place” experience usually depends on subjective factors. Simple steps that have nothing to do with skill or knowledge level, can be taken by any human with just a little common sense. Getting the equipment/syringes/solutions ready prior to patient’s entrance into the procedure room if possible, is a simple step. Positioning yourself between the tray and the patient, so that needles are not constantly passing in front of the patient, is another example on how to minimize patient anxiety during procedure.

Most importantly, remember that you are dealing with a human who came to you for help with their pain or need for follow up of some sort. Becoming an expert who can place a needle into sub-millimeter degenerated joint space using 20 cm needle will require time and experience. But, being nice and friendly when dealing with people is something that can be done with no advanced training at all. Those “people” skills you hopefully learned during your toddler years.