Spinal Anesthesia Is the Smart Choice

One of outpatient surgery's hottest specialties is fueling the rise of spinal anesthesia. "Before we performed total joints in surgery centers, we hadn't utilized spinal anesthesia for any other procedures," says Mike MacKinnon, CRNA, who practices in Arizona. "Now we're using low-dose spinals — 0.8 cc to 1.0 cc of 0.75% bupivacaine ?— for total knees."

Mr. MacKinnon says this low dose lets surgeons perform total knees with sedation plus an adductor canal block and iPACK or popliteal ?plexus block. "The spinal wears off within 30 minutes to an hour in post-op, allowing the patient to start physiotherapy ?almost immediately," he adds. "The blocks also keep them pain free for up to 30 hours."

Surgeons are better able to perform total knees with a spinal block placed because of the significant benefit total paralysis of the lower extremity provides, according to Mr. MacKinnon.

Fast-acting, powerful and short in duration — spinal blocks are ideally suited for lower-body same-day surgeries, especially as more complex procedures such as total knee replacements migrate to outpatient centers.

The use of chloroprocaine as a spinal anesthetic began to develop in the 2000s, and the FDA approved it for use as a spinal anesthetic in 2017. It had fallen out of favor because of adjutant preservatives that caused some neurologic problems, according to Michael Aziz, MD, a professor of anesthesiology and perioperative medicine at Oregon Health & Science University in Portland. He says those preservatives are no longer present in modern preparations.

"Preservative-free chloroprocaine anesthetics are well-suited for ambulatory surgery," he notes. The drug is fast-acting, usually taking full effect in three to five minutes after injection, but it also breaks down quickly — making it a great tool for the rapid in-and-out pace of outpatient surgery.

Dr. Aziz says the blocks reliably last 60 to 90 minutes, and reliably return motor and bladder function as well. Unless sedatives are used in tandem, the patient is fully conscious during the operation, and less likely to suffer the kinds of hangover effects experienced by patients who undergo general anesthesia.

"I'd say the over the last couple of years, as we've started to see joint arthroplasties performed in ambulatory centers, chloroprocaine is being used as a spinal anesthetic," he says. "It also supports knee procedures — arthroscopy, ACL reconstruction and meniscal surgery."

Cholorprocaine is also terrific for short procedures such as inguinal hernias and knee scopes, after which you don't want the patient to stay in PACU for hours, according to Jinlei Li, MD, PhD, FASAM, director of regional anesthesiology at Yale New Haven (Conn.) Hospital Saint Raphael Campus and the Center for Musculoskeletal Disease.

Dr. Li is a proponent of using ultrasound to place spinal blocks. She finds it especially useful for obese patients. "Spinal anesthesia is performed at the center of the back," she says. "When a patient is big, sometimes it becomes difficult to know where the midline is."

Providers face the same issue with patients who are injured. "Hip fracture patients are positioned lying flat on the side in the lateral decubitus position," says Dr. Li. "For patients who have had multiple spine surgeries, scar tissue and the implants make it difficult for you to place spinal anesthesia. That's when the ultrasound becomes very useful. We know where we should go, and it also tells us how deep the spinal space is, so we can use the right needle going in and point it in the right direction. Ultrasound can increase the success rate."

Successful application of spinal anesthesia also reduces the need for intraoperative and postoperative opioid usage, according to Dr. Li. "Patients who've had successful spinal anesthesia won't need opioids for the duration of the surgery," she says. "In the recovery room, after the spinal anesthesia starts to wear off, and even after the patient starts to move around, there's still some pain control effect."

During surgery, hypotension could occur if blood pressure or heart rate is low, or if the level of the spinal anesthesia is higher than it should have been, says Dr. Li. This problem is not unique to spinal anesthesia, she points out.

A recurring issue with spinal anesthesia isn't clinical. It's getting consent from the patient to apply it. "One of the common contraindications to spinal anesthesia is a patient's flat-out refusal to get a needle in their spine due to fear of nerve damage, but this risk is overblown," says Ashish Sinha, MD, PhD, DABA, MBA, FASA, a professor at the University of California Riverside, and designated institutional official and program director of anesthesiology at UC Riverside/Riverside Community Hospital.

Interestingly, the COVID-19 pandemic may lead to an increase in administrations of spinal anesthesia — even among patients averse to the technique. The reason? Intubation for general anesthesia is inherently dangerous and should be avoided unless absolutely necessary — especially with an unchecked virus spreading that has no vaccine or cure.

"When you administer a general anesthetic, as opposed to a spinal anesthetic, you have to put a breathing tube in the patients' trachea, which is an aerosolizing procedure," says Dr. Sinha. "Anything from the lungs of that patient, including viruses, may be released into the air of the room and land on any surface, including exposed skin or mucous membranes." That, of course, presents a risk of viral exposure to the OR staff.

"Patients may be easier to convince or medical providers may push a little harder for spinal anesthesia in the post-COVID-19 future," says Dr. Sinha. "The most important thing is consistent messaging. If the surgeons, anesthesiologists and nursing staff are all saying the same thing — 'In your case, spinal anesthesia is the best way' — then patients are more likely to respond to that message."

Dr. Li says postoperative side effects of spinal anesthesia are uncommon and usually clear up quickly. They can include lower extremity pain or headache, which could be accompanied by double vision, especially in younger patients. You'll want to ask patients if they have experienced any of these issues when making follow-up calls the day after surgery.

Patient selection and assessment, including a history and physical examination of the injection site, is critical for successful use of spinal anesthesia and avoidance of complications due to contraindications. "As always, clinical care needs to be individualized," says Dr. Aziz. "That said, I think there's a lot of utility in some standardization, adhering to set pathways that are associated with reduced complications. There's a benefit to setting up a primary pathway for a host of surgical procedures, and I think spinal anesthesia has a clear home in that."

When spinal anesthesia is administered, the needle passes through the epidural space into the subarachnoid space, where the cerebrospinal fluid resides. It takes effect much more quickly than an epidural — usually three to five minutes. Spinal is a home run for lower extremity, lower abdominal, pelvic and perineal procedures. Spinal immobilizes and desensitizes everything below the injection site, but the block wears off quickly, and bladder function and mobility are rapidly restored. Side effects are few — a slight headache is the most commonly reported one. All of this is perfect for outpatient surgery. OSM

Managing Editor Jared Bilski contributed reporting to this story.