Equipment

Trice Medical Seg-WAY disposable system

4 mm 30-degree endoscope

Marking

Mark a 2 cm transverse incision 1 cm proximal to the distal wrist crease. 

Antibiotics

None. 

Local Anesthesia

Give local anesthesia at least 30-45 minutes before case start.

Draw up two 10-cc syringes of local for each hand. Use a 27-gauge needle (very small). 

1 cc of 8.4% sodium bicarbonate 1 mEq/mL and 10 ccs of 1% lidocaine with epinephrine 1:100,000. The sodium bicarbonate reduces burning associated with administration. 

Ask the patient to touch their thumb and little finger to see if they have a palmaris longus tendon and mark its location. Avoid administering local anesthetic directly into the tendon as it will be ineffective. 

Clean the skin with an alcohol prep pad. Raise a weal along the planned incision line. Be sure to remain superficial, in the dermal layer. Carry the weal distally onto the palm, between the thenar and hypothenar eminences. Keep successive needle punctures within the border of the weal to minimize patient discomfort. 

After injection of 10 ccs (one of the two syringes), return to the planned incision and inject 3 ccs directly into the carpal tunnel to anesthetize the median nerve itself. Avoid the marked palmaris longus tendon. To do this, insert the tip of the needle just under the skin then apply pressure to the syringe to "raise a head of pressure" before advancing it further into the carpal tunnel. It is done this way so that the anesthetic diffuses into the compartment and pushes structures out of the way. 

Positioning

Supine on a regular table, relevant arm extended at a 90-degree angle on a board.

Take two narrow pink foams and tape them into a roll. Place this roll under proximal upper arm to support the arm as the patient holds it off the arm board. 

Prep

Ask the patient to keep their arm raised off the arm board and prep from the fingertips to the forearm. It is helpful to use two Chlorapreps and prep both sides of the hand at the same time to keep it from flopping around. 

Draping

1. Unroll a stockinette over the hand and down the forearm and arm
2. Place a drape on the arm board
3. Remove the roll from behind the proximal arm
4. Let the arm rest on the arm board
5. Pass the arm through the arm-hole of the carpal tunnel drape and pass the "up" part to anesthesia
6. Place a rolled blue towel behind the wrist or use the disposable plastic arm board that comes with the kit

Procedure

The procedure is done sitting on a stool. For the right-handed surgeon, sit on the same side as the patient's head for the left hand and on the same side as the axilla for the right hand. The assistant sits across from the surgeon. 

Cut through the stockinette with scissors to expose the wrist.

Use toothed Adson forceps to pinch the skin at the planned incision to verify local anesthesia. 

Use a 15 blade to make a shallow skin incision, just through the dermis. 

Use short tenotomy scissors to spread the subcutaneous tissue to the transverse carpal ligament. Always spread parallel to the nerve, never perpendicular to it. You can and should spread aggressively at this stage. Stop when you see the silvery sheen of the transverse carpal ligament. 

The assistant and surgeon both take Sen retractors. The surgeon and assistant alternate in sweeping the soft tissue off the ligament using the non-rake side of the Sen retractor.

Once the soft tissue is cleared off the ligament, use the point of the tenotomy scissors to puncture the ligament and spread it open. Again, spread only parallel to the nerve. 

Use the curved, flat end of the synovial elevator/dilator to feel the edge of the opening in the transverse ligament and verify that you are through it. 

Flip the instrument and push the dilating end into the carpal tunnel until you feel it under the skin of the palm, about 5 cm. 

Ask for the double-ended dilator and again dilate the tract through the carpal tunnel in the same fashion. Start with the more pointed end of the dilator then flip it over and use the larger blunt end. 

Finally, place the medium-size left or right endoscope guide into the carpal tunnel and push it all the way in. 

Place the 30-degree angled endoscope in the radial track with the bevel pointing towards the ulnar track. 

Look for the striated appearance of the transverse ligament.

Be aware that the median nerve can be between your view and the transverse ligament. If it is, or if soft tissue obscures your view of the ligament, remove the endoscope and use the endoscope guide to sweep tissue to the right and left in an attempt to clear your view of the transverse ligament. Replace the endoscope after the sweeping maneuver.

Place the ligament rasp in the ulnar track and use it to gently sweep soft tissue from the underside of the transverse ligament. Use the canting maneuver to lever the end of the instrument into the ligament. 

Use the ligament probe to define the distal edge of the transverse ligament. You should see the tip of the probe drop into the empty space on the far side of the ligament. 

Next, use the retrograde knife to cut through the ligament. Place the tip against the distal edge of the ligament and pull it towards you to cut the ligament. You should feel the knife cutting through the fibrous ligament. 

As you approach the proximal edge of the ligament, be careful not to pop right out of the incision and introduce a "T" cut to your skin incision. 

Withdraw the endoscope guide and finish the cut through the proximal ligament with tenotomy scissors. 

Closure

Single layer closure. Running subcuticular 4-0 Monocryl or running horizontal mattress 3-0 nylon. 

Dress with a single large Band-aid across the wrist.

Postop

Patients go home the same day. Follow up in 2 weeks for suture removal if nylons were used. Follow up PRN if Monocryl was used.