Carpal Tunnel Syndrome: Minimally Invasive Endoscopic Carpal Tunnel Release

Edited By: Thomas Trumble, M.D.
Last updated Wednesday, October 11, 2006

Figure 1 - The median nerve is compressed at the wrist because the transverse carpal ligament has become contracted.
Figure 1 - The median nerve is compressed at the wrist because the transverse carpal ligament has become contracted.

Figure 2 - The median nerve supplies sensation to the thumb, index, middle, and half the ring finger as well as supplying the thumb muscle.
Figure 2 - The median nerve supplies sensation to the thumb, index, middle, and half the ring finger as well as supplying the thumb muscle.

Figure 3 - The endoscopic device being placed under the transverse carpal ligament.
Figure 3 - The endoscopic device being placed under the transverse carpal ligament.

Figure 4 - Rest and bracing provides the best relief.
Figure 4 - Rest and bracing provides the best relief.

Figure 5 - A small spoon shaped device is used to clean the under surface of the ligament.
Figure 5 - A small spoon shaped device is used to clean the under surface of the ligament.

Figure 6 - Dilators help to compress the tissues in the carpal canal to make it possible to insert the endoscopic device.
Figure 6 - Dilators help to compress the tissues in the carpal canal to make it possible to insert the endoscopic device.

Figure 7 - Once the ligament is clearly seen, the small blade in the device is used to release the ligament in stages.
Figure 7 - Once the ligament is clearly seen, the small blade in the device is used to release the ligament in stages.

Summary

Overview

Endoscopic carpal tunnel release (endo-CTR) surgery helps to relieve the pain and numbness caused by carpal tunnel syndrome. In carpal tunnel syndrome (CTS), the median nerve is compressed at the wrist because the transverse carpal ligament has become contracted as a result of activities, aging or both. (Figure 1) The median nerve supplies sensation to the thumb, index, middle, and half the ring finger as well as supplying the thumb muscle. (Figure 2) Patients with CTS often have numbness, particularly at night, and weakness.

After performing a clinical examination and obtaining a test called an EMG/NCV (Electromyogram and Nerve Conduction Velocity) the surgeon can find out the cause of the numbness and determine the severity of the carpal tunnel syndrome (CTS) if it is present. Although mild cases of CTS can be managed with bracing and nonsteriodal anti-inflammatory medication, moderate and severe cases are best managed by surgery. The goal of endoscopic carpal tunnel release (endo-CTR) is to release the tight ligament over the median nerve to relieve the patient's symptoms. The figure 3 shows the endoscopic device being placed under the transverse carpal ligament. The device uses a camera and a fiber optic cable to see the ligament with a small incision that is placed in the wrist instead of the palm where incisions can cause greater scar sensitivity.

Endoscopic carpal tunnel release (Endo-CTR) is a highly technical procedure and is best performed by a surgical team, which performs this surgery often. Such a team can maximize the benefit and minimize the risks. The 30-minute operation is usually performed under regional anesthesia although general anesthesia is safe as well. In regional anesthesia the patient's arm is made numb with a nerve block but they do not have to go to sleep with general anesthesia.

Patients are allowed to move their hand and wrist immediately after surgery. The surgery is out patient surgery so the patient goes home the same day as the surgery.  Two days after the surgery, the patients can take their bandages off and shower. The patient can resume most light activities within days after the surgery but strong grip strength can take 4-6 weeks to return.

Characteristics of carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a condition in which the median nerve is compressed so that the patients experience numbness, pain and occasionally  weakness.  The nighttime numbness often causes the patient to wake up and shake their hand. CTS usually progresses slowly over time but the rate varies widely. When the patient has to flex their wrist for an activity, i.e. holding a steering wheel or hair dryer, numbness can occur.

Types

Carpal tunnel syndrome can be mild, moderate or severe. Mild CTS is often causes intermittent numbness. In moderate CTS the symptoms cause frequent nighttime wakening. In severe CTS, the patients often notice weakness  and they can drop objects without realizing it.

Similar conditions

Sometimes a pinched nerve in the neck (cervical radiculopathy) can cause hand numbness and the electrical test (EMG/NCV) can determine if this is present. Hand arthritis can cause hand pain but should not cause hand numbness.

Incidence and risk factors

CTS is very common with the peak incidence at age 55. Although both men and women can develop CTS, the condition is more common in women than in men.

Diagnosis

CTS is diagnosed by the patients history, physical examination and electrical diagnostic studies (EMG/NCV). The history of nighttime numbness, combined with an examination of tenderness over the wrist (Tinel's sign) and increase numbness with wrist flexion (Phalen's sign) help to make the diagnosis. In the Tinel's test, tapping the wrist often produces electrical like sensations going into the fingertips. The EMG/NCV is a test performed by a neurologist or physiatrist that measure the speed of nerve conduction.  When there is pressure on the nerve the conduction speed significantly decreases.

Medications

Braces worn at night can be very helpful by decreasing the nighttime numbness and helping the patients sleep. Nonsteriodal anti-inflammatory drugs (NSAIDs) like ibuprofen can help to relieve the symptoms but they do not provide a cure. These medications can be helpful for short-term use but most patients usually do not take these medications on a chronic basis for their CTS because there can be side effects associated with chronic NSAID use.

Exercises

Exercises generally do not help because they increase the swelling around the nerve. Rest and bracing provides the best relief. (Figure 4)

Possible benefits of endoscopic carpal tunnel syndrome

Endoscopic carpal tunnel release (endo-CTR) releases the pressure on the nerve and restores its normal blood supply. Studies of endo-CTR have demonstrated that patients generally regain their original strength with significant improvement in their symptoms <sup>4</sup> <sup>3</sup>Therapy after surgery can help the patients reduce scar formation and increase their strength. The patients at home usually do these exercises. The patients can return to nearly all activities within several weeks. By three months, studies have shown that the patients have recovered to a point where there was no difference in sensation and strength when the hand with CTS was compared to the other hand that had no symptoms.

Types of surgery recommended

Carpal tunnel release is a very reliable surgery. It can be done as an open technique with an incision in the palm or as an endoscopic technique that uses special technology with fiber optic cables and a camera to help the surgeon see the ligament that needs to be released without making a larger incision in the palm. There is one endoscopic technique that requires 2 incisions and one that only requires a single incision. The single incision technique is the only method that avoids an incision in the palm.

Who should consider endoscopic carpal tunnel syndrome?

Endoscopic Carpal Tunnel Release is considered when:
  • The patient has recurrent problems with numbness that interferes with activities or sleep.
  • The EMG/NCV is positive.
  • The patient understands the risks and alternatives
  • The surgeon is experience in endo-CTR.
  • Endo-CTR is helpful when carpal tunnel syndrome is confirmed in patients of all ages and all walks of life. It can be performed as an outpatient surgery with minimal risk to the patient.

What happens without surgery?

The numbness with carpal tunnel does not tend to improve, and it generally progresses slowly overtime. The rate of change in symptoms can vary. Some patients may develop permanent weakness if the pressure on the nerve is not relieved.

Surgical options

Most surgeries for CTS release the ligament to take the pressure off of the nerve. Ligament release techniques can be open or endoscopic with a smaller incision. Less common techniques involve stripping the lining off the tendons (synovectomy) or expanding the ligament. Without a release of the ligament, there is the problem of the pressure returning.

Effectiveness

In the hands of an experience surgeon, the technique can provide permanent relief. It is rare to have to revise the surgery.

Urgency

Surgery for CTS is not an emergency. The surgery should be scheduled when the symptoms cause a significant irritation to the patient. Although surgeries can be performed on both hands at the same time if both are significantly affected, most patients prefer to stagger the surgeries at least one month or more apart.

Risks

The risks of endoscopic carpal tunnel release include but are not limited to nerve injury infection, recurrence of the symptoms, tendon injury and scar tenderness. An experienced hand team will use specialized techniques to minimize these risks but cannot totally eliminate them.

Managing risk

Infections are extremely rare in carpal tunnel surgery but antibiotics can treat them. Nerve or tendon injury can be treated by surgical repair. Recurrence of symptoms can be treated by revision surgery. In one study of 10,000 consecutive cases of single incision endoscopic carpal tunnel surgery, there were no long-term complications that required revision surgery.2

Preparation

There is very little preparation required prior to endoscopic carpal tunnel surgery. The patient should plan on or more weeks off work depending on their type of work. They should plan to minimize the writing and typing for several weeks. They will need to schedule someone to bring them home from surgery.

Timing

In moderate cases the surgery can be delayed until the symptoms of numbness, tingling or pain become bothersome. In severe cases, a long delay can result in the permanent loss of muscle function.

Costs

The surgeon's office should provide a reasonable estimate of:
  • The surgeon's fee
  • The hospital fee
  • The degree to which these should be covered by the patient's insurance

Surgical team

An experienced surgeon who is certified in the technique should perform endoscopic carpal tunnel release. Patients should inquire as to the number of Endoscopic carpal tunnel release procedures that the surgeon performs each year and the number of these procedures performed in the medical center each year.

Finding an experienced surgeon

Not every community has a surgeon who is experienced in endoscopic carpal tunnel surgery. Surgeons specializing in shoulder joint replacement may be located through university schools of medicine, county medical societies, or state orthopaedic societies. Other resources include local rheumatologists or professional societies such as the American Society of Hand Surgery.

Facilities

Endoscopic carpal tunnel surgery is usually performed in a skilled and accredited outpatient surgery unit that routinely performs endoscopic  or arthroscopic  surgery. They have anesthesiologists, nurses and even therapists who are skilled in managing patients with hand surgery.

Technical details

Endoscopic carpal tunnel release is a highly technical procedure that requires microscopic techniques and the correct endoscopic equipment with the necessary back up equipment. After the anesthetic has been administered, a small incision in marked out on the wrist just proximal to the palm (see video). The superficial tendon and small veins are carefully retracted to prevent nerve injury. An 'L' or 'U' shaped incision is made in the first layer called the flexor retinaculum. This layer is lifted up as a flap that forms a doorway into the carpal tunnel. A small spoon shaped device (synovial elevator) (Fig. 5) is used to clean the under surface of the ligament to provide a good view with the endoscope. Dilators help to compress the tissues in the carpal canal to make it possible to insert the endoscopic device with minimal pressure. (Fig. 6) The endoscopic device is inserted carefully so that the ligament can be seen along its entire length. Often the device is warmed to prevent fogging. Once the ligament is clearly seen, the small blade in the device is used to release the ligament in stages. After making sure that important nerves and arteries are protected. (Fig. 7) Once the ligament is completely released, the rest of the flexor retinaculum in the wrist is release with a special type of scissors. Local anesthetic is injected for post-operative pain relief and the incision is sutured. A soft bandage is applied for the patient to keep on for two days to reduce swelling. After two days they can remove the larger dressing and apply a Band-Aid. They can shower and change the Band-Aid but they should not soak the hand in water such as a sink, pool or bathtub until the suture has been removed in about 10 days.

Anesthetic

Most patients opt for a regional anesthetic called intravenous regional or a Bier Block. They can stay awake for the procedure with or without sedation.  The Bier block is very safe and wears off quickly after surgery.  They can also choose a general anesthetic. The patient may wish to discuss their preferences with the anesthesiologist before surgery.

Length of endoscopic carpal tunnel syndrome

The actual procedure takes about 30 minutes but the total time for the anesthetic, preparation, surgery and bandaging takes about one hour. To allow for time for check in and recovery the patients should plan at least a half-day for the surgery.

Pain and pain management

Endoscopic carpal tunnel surgery is a minimally invasive procedure. The patients often use oral medication after the surgery for a few days. Oral medications include synthetic narcotics such as oxycodone or hydrocodone.

Use of medications

Patients receive oral and intravenous pain medication in the recovery room. A prescription for oral pain medication is given to the patients at the time that they leave the surgery center.

Effectiveness of medications

Pain medications can be very powerful and effective. Their proper use lies in the balancing of their pain relieving effect and their other, less desirable effects. The patients often advance to Tylenol or ibuprofen within a day or two.

Important side effects

Pain medications can cause drowsiness, slowness of breathing, difficulties in emptying the bladder and bowel, nausea, vomiting and allergic reactions. Patients who have taken substantial narcotic medications in the recent past may find that usual doses of pain medication are less effective. For some patients, balancing the benefit and the side effects of pain medication is challenging. Patients should notify their surgeon if they have had previous difficulties with pain medication or pain control.

Hospital stay

The patients are usually monitored for an hour in the recovery area. Instructions for office appointments,  post-operative instructions, and pain medication are provided. The patients are escorted out of the surgery center by a family member or friend.

Recovery and rehabilitation in the hospital

The patients are encouraged to change their bandages to a small Band-Aid two days after surgery. About 10 days after surgery, their sutures are removed and a therapy program is reviewed with them with instructions for them to take home. Patients are advised to avoid heavy activities for about a month after surgery.

Hospital discharge


Convalescent assistance


Physical therapy


Rehabilitation options


Can rehabilitation be done at home?


Usual response


Risks

This is a safe rehabilitation program with little risk.

Duration of rehabilitation

The patients should follow their instructions for stretching, strengthening and scar massage for about two weeks.

Returning to ordinary daily activities

The patients can drive within a day or two after surgery. The can cover the bandage with plastic bag to shower for the first two days and then change the bandage and use a small Band-Aid. They can do limited typing and writing within a week after surgery and advance as dictated by their symptoms. Within a month after surgery, most patients have returned to all activities. Some patients notice that there strength and sensation improves for three months for certain activities such as opening tight jars or bottles.

Long-term patient limitations

There no long term limitations after endoscopic carpal tunnel surgery.

Costs


Summary of endoscopic carpal tunnel syndrome for carpal tunnel syndrome

Endoscopic carpal tunnel surgery is a very successful surgery to restore patient comfort and relieve symptoms of numbness, tingling and weakness that can affect activities and sleep.

In the hands of an experienced surgeon, endoscopic carpal tunnel release is highly effective with a low rate of complications. Proper diagnostic work up with physical examination and EMG/NCV can insure that the procedure is done for the correct indications.

References

  1. Agee, J. M.; McCarroll, H. R.; and North, E. R.: Endoscopic carpal tunnel release using the single proximal incision technique. Hand Clin, 10(4): 647-59, 1994.
  2. Agee, J. M., Peimer, C.A., Pyrek J.D., Walsh W. E.: Endoscopic carpal tunnel release: a prospective study of complications and surgical experience. J Hand Surg, 20A: 165-171, 1995.
  3. Palmer, D. H.; Paulson, J. C.; Lane Larsen, C. L.; Peulen, V. K.; and Olson, J. D.: Endoscopic carpal tunnel release: a comparison of two techniques with open release. Arthroscopy, 9(5): 498-508, 1993.
  4. Trumble, T. E.; Diao, E.; Abrams, R. A.; and Gilbert-Anderson, M. M.: Single-portal endoscopic carpal tunnel release compared with open release: a prospective, randomized trial. J Bone Joint Surg Am, 84-A (7): 1107-15, 2002.

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Surgery for carpal tunnel syndrome at the University of Washington

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