PLANNING THE SURGERY: Visiting surgeon Dr. Joel Heiser, left, looks on as surgeon Dr. Robert Lock points out his patient’s degenerative hip arthritis on an x-ray prior to performing hip-replacement surgery Thursday morning at Western Arizona Regional Medical Center. JAMES CHILTON/The Daily News

Surgeon shows visiting colleague latest techniques in hip replacement

By JAMES CHILTON/The Daily News

BULLHEAD CITY — Western Arizona Regional Medical Center orthopedic surgeon Dr. Robert Lock played part-host, part-teacher Thursday to a visiting surgeon from San Diego, who came to Bullhead City to observe Lock’s state-of-the-art techniques for hip and knee replacement surgery in action.

Dr. Joel Heiser, who splits his time between the Scripps Encinitas hospital in San Diego and the Tri-city Medical Center in Oceanside, Calif., said he was interested in adopting Lock’s techniques in his own practice, but had only previously worked with the technology involved in a cadaver course.

“We were using this computer navigation technology that Dr. Lock uses,” Heiser said. “And the representative from the company (that markets it) suggested that if I wanted to observe a surgeon one-on-one, that Dr. Lock does a lot of cases with that navigation and this approach.”

The surgery includes several fairly recent innovative approaches, including a frontal — or anterior — incision, as well as a computer system designed and marketed by Zimmer Southwest that allows the surgeon to use triangulation to better determine exactly where to position the replacement hip. Lock said the anterior incision allows him to work around the thigh muscles rather than slicing through them, reducing overall recovery time and increasing the patient’s ability to utilize the new joint quickly. The computer, meanwhile, provides him with a way to minimize the chance of post-op dislocation by providing precise measurements, including both angles and depth.

“What the computer does is set up a sort of GPS system around the joint; it gives us sort of a coordinate system on which to base the position of our components,” Lock said. “When the patient’s lying on the table, everybody’s pelvis is laying in a different position. When we use the computer, we can get a more accurate position of the patient’s pelvis in space.”

It might sound strange to a layman, but both Lock and Heiser agreed it can make the difference between a new hip fitting perfectly or fitting poorly. Lock noted that one crucial aspect of the technology is its ability to provide real-time feedback on the “reaming” process — the point at which the old hip bone has been removed and the empty pelvic socket is ground down to a smooth surface to accept the new artificial hip.

“What we’ve seen when we’re using this computer, there’s so much more consistency when you look at the post-operative x-rays,” Lock said. “This gives us an unbelievable amount of information. There’s this iceberg under the water we’re just now beginning to see.”

Lock, who has performed about 600 knee and hip replacements over the last three years using the Zimmer technology, said it reduces both patient recovery time and the likelihood that the patient will have to return for an adjustment. That said, he admitted the technology can sometimes be a hard sell to hospital administrators, given that many of the cost savings are only obvious in the long term.

“But if patients sense there’s better quality of care, they will tend to go to that, which will cause volume shifts,” he added.

Thursday’s surgery, which lasted just over an hour, was performed on a 72-year-old Bullhead City woman suffering from degenerative arthritis. According to anesthesiologist Dr. LeMonte Wood, the woman should be able to go home in time for the weekend, thanks in part to yet another innovation — Lock’s decision to use various pain management drugs prior to applying general anesthesia.

“When pain occurs, the nerves become hypersensitive, so we give a number of medications that are customized to the patient that target the pain receptors before the pain stimulus actually occurs,” Wood said. “It’s like a pre-emptive strike, and if you compare post-operative pain scores, they’re greatly reduced.”

Wood said that, even though a patient under general anesthesia won’t feel pain during their surgery, it still causes biological changes that result in post-op pain, which is difficult to address once it’s been inflicted. But by essentially shutting down the pain receptors prior to applying anesthesia, the patient feels next to nothing afterward — zero to one on a pain scale of 10, Lock said. Wood noted that the pre-op drugs used include NSAIDs — non-steroidal anti-inflammatory drugs — opioids like Percoset and Vicodin, and a central nervous anesthetic called Lyrica, which directly affects the brain chemicals that transmit pain signals throughout the body.

“Instead of five days, they’re out of here in 36 hours or less, walking,” Wood said. He added that, by lessening the “depth” of the general anesthesia, patients are also less likely to experience post-op nausea, of which he said treating is one of the biggest post-op expenses hospitals face.

Heiser said the surgery gave him some excellent insight into the technology involved, thanks in no small part to Lock’s engagement and willingness to answer questions.

“Dr. Lock was very clear, he allowed me to ask questions and understand what he was doing, and he was very patient,” Heiser said. “It was a great opportunity for me, extremely helpful and very much appreciated.”

With another half-dozen knee and hip replacements to go for the day, Heiser continued to observe Lock throughout the morning. He said he was particularly interested in observing the knee replacements, which is something he hasn’t tried using the navigation technology yet.

“After this, it’ll depend on my comfort level,” Heiser said. “I’ve been doing total hips for a long, long time. Between a cadaver course and observing four cases here, I may be ready to go.”