Carpal tunnel syndrome is the most common entrapment neuropathy and a condition for which many patients seek treatment, according to Mark A. Mahan, MD, FAANS. He calls carpal tunnel release the “poster child” of successful surgery and says the efficacy of the procedure is backed by numerous randomized controlled trials, making it a viable treatment option even in the absence of conservative medical management.

Open carpal tunnel surgery is a low risk, low morbidity procedure, but can result in slower recoveries, increased risk of post-op wound issues and more postoperative pain. “Endoscopic surgery takes it up a notch,” says Dr. Mahan, an associate professor of neuro and spine surgery and chief of the division of peripheral nerve and pain surgery at University of Utah Health in Salt Lake City. “In my hands, the procedures are faster, safer and have better success rates in terms of fewer complications and improved recoveries.”

Dr. Mahan points out that success in surgery begins with a successful diagnosis, which is relatively straightforward in patients suffering from carpal tunnel syndrome. “It requires combining clinical manifestations — the signs and symptoms of the disease — with objective tests such as electrodiagnostic studies and ultrasound imaging,” says Dr. Mahan. “Success rates will be high if you take a thoughtful approach to the surgery.”

Before surgery, he performs an ultrasound of the patient’s wrist and hand to identify potential masses or complex anatomy that would make the endoscopic approach too challenging to attempt. 

“Surgeons don’t have the ability to explore anatomy during a carpal tunnel release,” explains Dr. Mahan. “It’s imperative to identify potential issues such as nerve sheath tumors or ganglion cysts with pre-op imaging beforehand.”

Although he has performed revisions endoscopically, his preference is to treat them as open procedures because of the higher likelihood of adherence between the median nerve and scar tissue from the previous surgery. 

In my hands, the procedures are faster, safer and have better success rates.
— Mark A. Mahan, MD, FAANS

On the day of surgery, Dr. Mahan discusses with the patient the details of the procedure, the risks involved, how he expects the case to proceed and the normal progression of recovery. The anesthesia provider then administers a light sedative before the patient is brought to the OR, where the surgical team conducts a time out to confirm the correct side and site of the surgery. The patient receives a dose of IV antibiotics while Dr. Mahan places a forearm tourniquet just below the patient’s elbow crease and exsanguinates the hand because, he says, the small size of the camera used for the endoscopic approach requires a bloodless surgical field.

The anesthesia provider then uses the dorsum IV started in pre-op to place a Bier block with straight lidocaine. (Dr. Mahan says some providers add ketorolac.) After the block is placed, the hand is prepped with sterile paint and Dr. Mahan is ready to begin the procedure, which he completes in about 10 minutes.

When performing the endoscopic approach, Samuel E. Galle, MD, enters through a 1cm incision made in the distal wrist crease, dissects down to the fascia and introduces the synovial elevator and dilators before inserting the endoscopic camera and cutting device with a retractable blade. “To achieve good visualization of the median nerve, I move distally in the carpal tunnel to look at the palmar adipose tissue and make sure synovium isn’t present on the transverse carpal ligament,” says Dr. Galle, a fellowship trained surgeon specializing in hand and upper extremity surgery who practices with Proliance Surgeons in Kirkland, Wash.

After Dr. Galle achieves good visualization of the transverse carpal ligament, he cuts through it by making multiple passes with the cutting device. After the ligament is released, he performs a subcuticular closure.

Dr. Galle prescribes a more powerful analgesic to treat excessive pain in the small percentage of patients who might experience significant post-op discomfort, although he says most don’t opt to use the medication. Dr. Mahan says his patients receive ketorolac during surgery and are prescribed a course of anti-inflammatories to manage pain at home.

Patients appreciate the faster recoveries and returns to routine life activities afforded by endoscopic carpal tunnel surgery, according to Dr. Mahan. He tells his “high-demand hand” patients — those in manual labor jobs — to avoid strenuous work for two weeks. Office workers are often back on the job within a couple days, he says.

The pros and cons of performing bilateral surgery is a common topic of conversation among surgeons, notes Dr. Mahan. “There’s limited evidence that shows bilateral surgery results in slower recoveries,” he says. 

Many patients prefer the quicker convalescence afforded by minimally invasive carpal tunnel release, but surgeon experience often dictates whether they perform open or endoscopic surgery. Surgeons who opt for the open technique believe it’s not necessary to stop performing a proven procedure. Others have raised concerns about the increased risk of causing damage to the median nerve due to visualization problems associated with the endoscopic approach. Dr. Galle says surgeon training and the tools used during endoscopic surgery have evolved considerably in recent years, factors that have improved the safety of the approach and should lead to widespread use of the technique.

Dr. Mahan believes it’s only a matter of time before adoption rates of endoscopic carpal tunnel release increase. “More procedures will be performed when younger surgeons who were trained on the technique enter the workforce,” he says. OSM

Note: This three-part article series is supported by Hand Biomechanics Lab.