ADVANTAGES OF WALANT VERSUS SEDATION AND TOURNIQUET IN CUBITAL TUNNEL DECOMPRESSION SURGERY

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  Positioning patients with their elbow above their head is much easier for your access as the surgeon. The anesthesiologist and his or her equipment will not be occupying your valuable surgical access space.

  
  
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  There is no tourniquet, so you have much easier access to the proximal incision.

  
  
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  Patients can position themselves comfortably so the elbow and the shoulder are not sore during the surgery. They do not wake up from general anesthesia with shoulder pain that we caused by putting their shoulder in a position it does not like.

  
  
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  You can see whether the ulnar nerve subluxates with active movement by watching patients actively flex and extend the elbow through a full range of motion before you close the skin. If the nerve subluxates, you can transpose it if required.

  
  
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  You can perform cubital tunnel decompression with field sterility or augmented field sterility (see Chapter 10).

  
  
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  All of the general advantages listed in Chapter 2 apply to both the surgeon and the patient.

WHERE TO INJECT THE LOCAL ANESTHETIC FOR CUBITAL TUNNEL DECOMPRESSION

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  See Chapter 1, Atlas, for more illustrations of the anatomy of diffusion of tumescent local anesthetic in the forearm, wrist, and hand.

SPECIFICS OF MINIMALLY PAINFUL INJECTION OF LOCAL ANESTHETIC FOR CUBITAL TUNNEL DECOMPRESSION

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  Inject 20 ml subcutaneously in the most proximal part of the incision, followed by 20 ml in the middle of the incision, and then 20 ml at the end of the incision.

  
  
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  Inject the anesthetic solution a minimum of 30 minutes before surgery to allow the epinephrine to take optimal effect and provide an adequately dry working field.

  
  
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  We inject supine patients on stretchers in a waiting area to decrease the risk of their fainting (see Chapter 6).

  
  
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  To minimize pain of injection, start with a fine 27-gauge needle (not a 25-gauge) into the most proximal injection point (red dot).

  
  
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  Ask the patient to look away. Press with a fingertip just proximal to the injection site before you put in the needle to add the sensory “noise” of touch pressure to decrease the pain.

  
  
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  Mix 30 ml of 1% lidocaine with 3 ml of 8.4% bicarbonate into a 50 ml bag of saline solution that contains only 30 ml. (You remove 20 ml from the 50 ml bag before adding the lidocaine.) This gives you 63 ml of 0.5% lidocaine with 1:200,000 epinephrine buffered 10:1 with 8.4% sodium bicarbonate.

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  Insert the first needle perpendicularly into the subcutaneous fat. Stabilize the syringe with two hands to avoid causing pain from needle wobble until the skin needle site is numb. Inject the first visible 0.5 ml bleb and then pause. Wait 15 to 45 seconds until the patient tells you that all needle pain is gone. Inject the rest of the first 10 ml slowly (over 2 minutes) without moving the needle.

  
  
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  Inject 20 ml at the proximal injection point of the incision, 20 ml at the middle injection point, and 20 ml at the distal injection point. Always reinsert injection needles into an area with 1 cm of blanched skin around it to ensure that needle reinsertion does not hurt.

  
  
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  Inject just under the skin. There is no need to inject into the cubital tunnel; it would only add unnecessary pain. The local anesthetic will diffuse into the tunnel.

  
  
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  If you want to perform endoscopic cubital tunnel decompression that goes farther distally in the forearm, you can inject another 20 ml or more distally in the forearm so that you have at least 2 cm of palpable or visible local anesthetic beyond your area of dissection.

  
  
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  For those who prefer anterior transposition, the soft tissue in the new nerve path will need to be more extensively flooded with another 20 ml of local anesthetic. The image on p. 138 shows local anesthetic injection for simple cubital tunnel release.

  
  
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  We have not worked out the technique for submuscular transposition at this time, since we do not do that operation. You would likely need to inject beneath the deep forearm fascia to accomplish that operation as a wide awake procedure.