Endoscopic carpal tunnel release through one or two incisions

Advocates of endoscopic carpal tunnel release cite less palmar scarring and ulnar “pillar” pain, rapid and complete return of strength and return to work, and activities at least 2 weeks sooner than for open release. The advantages of the endoscopic technique in grip strength and pain relief are realized within the first 12 weeks and seem to benefit those patients not involved in compensable injuries. Anecdotal reports of intraoperative injury to flexor tendons; to median, ulnar, and digital nerves; and to the superficial palmar arterial arch emphasize the need to exercise great care and caution when performing endoscopic release. There are two basic methods of endoscopic carpal tunnel release: single-portal (Agee) and two-portal (Chow) techniques.

Endoscopic carpal tunnel release through a single incision

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Ascertain that the operating room setup is satisfactory. Ensure there is an unobstructed view of the patient’s hand and the television monitor.
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Use general or regional anesthesia. Although the procedure can be done safely using local anesthesia, the increase in tissue fluid can compromise endoscopic viewing.
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Exsanguinate the limb with an elastic wrap and inflate a pneumatic tourniquet applied over adequate padding. Leave the arm exposed distal to the tourniquet.
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In a patient with two or more wrist flexion creases, make the incision in the more proximal crease between the tendons of the flexor carpi radialis and flexor carpi ulnaris ( Fig. 42.1 ).
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Use longitudinal blunt dissection to protect the subcutaneous nerves and expose the forearm fascia.
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Incise and elevate a U-shaped, distally based flap of forearm fascia, and retract it palmarward to facilitate dissection of the synovium from the deep surface of the ligament creating a mouthlike opening at the proximal end of the carpal tunnel ( Fig. 42.2 ).
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When using the tunneling tools and the endoscopic blade assembly, keep them aligned with the ring finger, hug the hook of the hamate, and keep the tools snugly apposed to the deep surface of the transverse carpal ligament, maintaining a path between the median and ulnar nerves for the instruments.
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Use the synovium elevator to scrape the synovium from the deep surface of the transverse carpal ligament. Extend the wrist slightly; insert the blade assembly to the carpal tunnel, pressing the viewing window snugly against the deep surface of the transverse carpal ligament. While advancing the blade assembly distally, maintain alignment with the ring finger and hug the hook of the hamate staying to the ulnar side. Make several proximal-to-distal passes to define the distal edge of the transverse carpal ligament with the fat overlying it ( Fig. 42.3 ).
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Define the distal edge of the transverse carpal ligament by viewing the video picture, ballottement, and light transilluminated through the skin. Correctly position the blade assembly and touch the distal end of the ligament with the partially elevated blade to judge its entry point for ligament division. Elevate the blade and withdraw the device, incising the ligament.
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Release distal half to two-thirds of transverse carpal ligament completely before making a final pass to release the remainder of the ligament. This prevents fat located superficial to the proximal portion of the ligament from dropping into the wound and compromising the surgeon’s endoscopic view of the extent of the ligament division ( Fig. 42.4 ).
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Using the unobstructed path for reinsertion of the instrument, accurately complete the distal ligament division with good viewing. Complete proximal ligament division with a final proximal pass of the elevated blade.
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Assess the completeness of ligament division using the following endoscopic observations.
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Through the endoscope, note that the partially divided ligament separates on the deep surface creating a V-shaped defect ( Fig. 42.5 ).
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Make subsequent cuts viewing the trapezoidal defect created by complete division as the two halves of the ligament spring apart. Through this defect, observe the longitudinal palmar fascia fibers intermingled with fat and muscle. Force these structures to protrude by pressing on the palmar skin.
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Confirm complete division by rotating the blade assembly in radial and ulnar directions, noting that the edges of the ligament abruptly “flop” into the window obstructing the view.
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Palpate the palmar skin over the blade assembly window observing motion between the divided transverse carpal ligament and the more superficial palmar fascia, fat, and muscle.
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Ensure complete median nerve decompression by releasing the forearm fascia with tenotomy scissors ( Fig. 42.6 ).
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Use small right-angle retractors to view the fascia directly avoiding nerve and tendon injury.
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Close the incision with subcuticular or simple stitches.
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Apply a nonadhering dressing. Apply a well-padded volar splint or, in selected patients, leave the wrist unsplinted.