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Expert surgeons continue the heated debate about carpal tunnel syndrome treatment
Although conservative and surgical modalities work in specific patients, complications can vary.
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The optimal treatment for carpal tunnel syndrome remains a hot-button issue among surgeons. Some of the most common regimens include open carpal tunnel release, limited release, endoscopic release and conservative treatments.
While passionate proponents back each modality, many agree that the indications for conservative treatment are limited, and that results from the different surgical options are similar.
“You should ask the question, ‘Is there any difference in the results of a carpal tunnel release whether you do it mini open, conventional open, or endoscopically?’” Barry P. Simmons, MD, the chief of hand and upper extremity service at Brigham & Women’s Hospital in Boston, told Orthopedics Today. “Nothing has proven that there’s any difference in the long-term results (more than three months after surgery). So in fact, the efficacy of the procedure seems to be the same whichever one you do. It’s the morbidity and complications that differ.”
Open release
Traditional open carpal tunnel release (CTR) gives surgeons full visualization of the hand structures, which may decrease the risk for nerve damage. The trade-off: increased sensitivity.
“Overall, I think that the incidence of complications for an open carpal tunnel release done in experienced hands is very low,” said Simmons, who is also an Orthopedics Today editorial board member. “[It is] probably in the 0.02% complication rate, meaning nerve injury. But, the major thing is the tenderness in the palm.”
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Images: AM Surgical |
Because the incision crosses the wrist, patients may experience tenderness for up to six months, American Society for Surgery of the Hand (ASSH) past president Jim Strickland, MD, told Orthopedics Today.
Strickland noted that the procedure had “considerable” disadvantages, including potential palmar bowstringing. “I certainly think there’s a higher incidence of recurrence, scarring and nerve adhesion from open carpal tunnel release because it just divides all the structures from the skin down to the nerve,” he said. “If you believe that tissues heal first as a single milieu of collagen tissue and ultimately redefine their linear lines, then I think it’s much more likely that a procedure that divides all the structures will become a scar bed than one that limits the division to the transverse carpal ligament itself.”
Proponents of limited or mini-open carpal tunnel release say that it decreases the morbidity of traditional open releases and avoids the potential for bowstringing. “[The incision] does not cross the wrist crease, which seems to be the area of the greater hypersensitivity and tenderness,” said Strickland, who is also an Orthopedics Today editorial board member. “It then, somewhat blindly, divides the remainder of the ligament proximally.”
To decrease postoperative morbidity of the limited open release — which is still less than the traditional open release — Simmons said the mini-open incision is best made more distally to avoid making the incision over the transverse carpal ligament at the base of the palm. According to Simmons, although some surgeons say they use a limited incision, but they put it over the base of the palm, which has the same problem as the traditional open technique, that is tenderness at the incision site.
Endoscopic release
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![James C.Y. Chow, MD [photo]](/~/media/images/news/online/orthopedics/2006/07_july/01/chow_70_90_17612.jpg)
Many surgeons also use endoscopic CTR to avoid the complications of open procedures. Instead of reaching the ligament from the outside of the hand, endoscopic release employs an inside-out approach. James C.Y. Chow, MD, president of the Arthroscopy Association of North America (AANA) and developer of the Chow technique, explained the reasoning behind endoscopic release.
Endoscopic carpal tunnel release has three purposes: preserve normal anatomical structures, increase safety and avoid serious complications, Chow said. He said that since its introduction, critics of the procedure have said that offers only short-term benefits and increases serious complications.
“This is a misconception. Let’s ask ourselves a few questions. First, what is the fundamental difference between endoscopic and open carpal ligament release?” he said. “The open surgery cuts from the outside in, and the endoscopic procedure cuts from the inside out. Next, where are the important structures? Are they inside the carpal canal or outside the carpal canal? Then ask yourself, which is safer: To cut it before you see it or to see it before you cut it?
“Of more than 3700 endoscopic carpal ligament release cases, I have witnessed 18 extreme ulnar transligamental motor branches of the median nerve. I have been able to save them because I see them first. I sincerely believe that if an open procedure had been performed, this nerve would have been damaged.”
While some studies found a decrease in morbidity, they also discovered more complications with the surgery, including severed median nerves. Simmons cited a prospective, randomized trial by RA Brown, RH Gelberman, JG Seiler, et al comparing 169 hands treated with either endoscopic or open release. The researchers discovered four complications in the endoscopic cohort, including a partial separation of the superficial palmar arch. Other potential injuries from the procedures include partial or complete laceration of the ulnar nerve and median nerve, palmar arch and flexor tendons, Simmons said.
Although the procedure carries a low injury rate, it remains twice that of open release, he said. “So as small as these complications may be, the severity of them is so great you’ve got to say, ‘Does the decreased tenderness in the palm and the more rapid return of grip strength justify the complications at that high a level, especially when the results are the same at three months postop?’” Simmons said. “For me, the answer has always been no.”
Unnecessary risks?
Strickland also agreed that the surgery might pose unnecessary risks. “In my mind, the endoscopic release was and is a triumph of technology over reason. [Because] that procedure can be accomplished more safely, I believe, with either limited or open carpal tunnel decompression,” Strickland said.
Yet, Chow reported a 0.14% complication rate out of more than 3700 endoscopic releases. Of these, he cites that he has had no permanent nerve injury, no tendon lacerations, no superficial palmar artery injuries and no reflex sympathetic dystrophy.
Chow et al reported on a study at the 1992 American Society for Surgery of the Hand Annual Meeting that revealed that most surgeons experienced complications during their first 100 endoscopic cases. The study also pointed out that 90% of the complications occurred when general or regional block anesthesia was used. The conclusion of the study suggests that local anesthesia is the safest, Chow said.
Simmons reported that he has never had a partial or complete nerve laceration in more than 5000 open or mini-open procedures.
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Ather Mirza, MD, chief of hand and microsurgery at St. Catherine of Siena Medical Center and Northshore Surgi Center in New York, said that complications result when surgeons fail to identify the vulnerable and aberrant distal edge of the transverse carpal ligament. “I felt that the identification of the anatomy in the palm is paramount to avoiding the complications,” he told Orthopedics Today. Further, he said that abnormalities rarely occurred proximally in the wrist and forearm. “What I’m saying is, make your incision distal in the palm and identify your anatomy so you’re less likely to harm any vital structures.”
In his own study of nearly 2000 endoscopic releases, Mirza reported no median nerve or palmar arch injuries. Most of his patients experienced symptom relief, and only 10% reported mild scar tenderness. “Postoperatively, the subjective complaints were minimal at four weeks, 80% had no pain, 70% reported no tingling, and 60% had no numbness,” he said. The conversion rate to open CTR was less than 1%, and the recurrence rate was 0.4%.
Five patients underwent conversion to an open release. Of these, one patient had an incomplete release. Mirza linked the study’s 1.6% conversion rate to the learning curve. He now converts less than 1% of cases to open CTR.
Detractors of the technique also argue that research shows similar postoperative function between endoscopic and open releases. Chow questions whether the endoscopic procedures in this study were performed properly. If all anatomical structures have been sacrificed except the skin, that means an open surgery has been performed through the scope. Then the results between open and endoscopic procedures will be similar, he said.
Through his cadaver research, Chow and his colleagues discovered the interthenar soft tissue band. This structure contains small vessels and nerves and lays just palmar to the carpal ligament. The band has not been described in Gray’s Anatomy. “Surgeons cannot identify these two separate layers through the open method; most believe it is part of the carpal ligament,” Chow said. “Preservation of this band can help decrease postoperative pain and prevent bowstringing of the median nerve and flexor tendon.”
Conservative treatments
Despite an array of surgical options, some experts contend that long-used conservative treatments can provide some symptom relief.
Image: Simmons BP |
“Conservative treatment has a place, but it’s fairly limited to patients who have had reasonably recent onset of their symptoms and are in the younger to middle-age group,” Strickland said. “It’s been shown that the likelihood of conservative measures, including injections of the carpal tunnel, of providing long-term benefits is not very good unless the patient is 40 years of age or younger and the condition has been present for less than nine months.”
In a recent randomized, controlled trial, researchers in Spain found better short-term results with steroid injections compared to surgical decompression in patients with a recent onset of CTS. Domingo Ly-Pen, MD, and colleagues conducted a one-year follow-up on 163 wrists allocated to either surgery or steroid injection treatment. The investigators discovered that 19% more of the steroid treated patients showed a 20% response for nighttime paresthesias at three months (P=.001). At one-year follow-up, rates shifted to 69.9% of the steroid group and 75% in the surgically treated cohort. “At one year, local steroid injection is as effective as surgical decompression for the symptomatic relief of CTS,” the researchers wrote in their abstract.
In response to the study, the American Society for Surgery of the Hand noted that the research also showed a slight trend toward surgery at one year and that longer follow-up may show better results with surgery. “If this study parallels the findings of other investigations, the success rate of injection can be expected to decline further with time while the surgery success rate remains constant or improves,” the society wrote in a press release.
Similarly, a new randomized control trial conducted in the Netherlands showed superior results with surgical treatment compared to splinting. Annette A.M. Gerritsen, PhD, and colleagues studied 176 patients treated with splinting or open carpal tunnel release. They discovered that more of the surgically treated group improved at three-month follow-up compared to splinted patients (P<.001), the researchers wrote in their abstract. The better results from surgery held out after 18 months (P=.02). “However, by that time, 41% of patients (32/79) in the splint group had also received the surgery,” the researchers wrote.
For more information:
- Brown RA, Gelberman RH, Seiler JG 3rd, et al. Carpal tunnel release: A prospective, randomized assessment of open and endoscopic methods. J Bone Joint Surg. 1993;75(9):1265-1275.
- Chow JCY, et al. Complications of endoscopic carpal tunnel release using the Chow Technique. Presented at the 47th Annual Meeting of the American Society for Surgery of the Hand. Phoenix.
- Domingo LP, Andréu JL, de Blas G, et al. Surgical decompression versus local steroid injection in carpal tunnel syndrome: A one-year, prospective, randomized, open, controlled clinical trial. Arthritis Rheum. 2005;52(2):612-619.
- Gerritsen AAM, de Vet HCW, Scholten RJPM, et al. Splinting vs. surgery in the treatment of carpal tunnel syndrome: A randomized controlled trial. JAMA. 2002;288:1245-1251.