Accessory first lumbrical muscle within the carpal tunnel: a case report.

Carpal tunnel syndrome is the most common entrapment neuropathy in the upper extremity. Palmaris longus, flexor digitorum superficialis, and lumbricals have infrequently been reported as causes of nerve compression. During routine Korean cadaver dissection, we incidentally identified an anatomic variant of first lumbrical muscle within the carpal tunnel in both wrists. The aberrant musculature originated from the radial side of the second FDS muscle at distal forearm level, running separately across the wrist beneath the flexor retinaculum. The dissected anomalous muscle was identified as an additional muscle belly of the first lumbrical muscle. Compression of the median nerve at the wrist might rarely be caused by the presence of such a tendon or muscle anomaly found in this study. Surgeons should be aware of possible anatomic variations in the carpal tunnel, and be prepared to modify their surgical plan accordingly.

Neglected posterior interosseous nerve injury.

Posterior interosseous nerve (PIN) injury is uncommon due to its anatomically deep location. We report a neglected, rare case of PIN injury presenting the loss of extension of thumb, index, and small fingers with weakness of thumb abduction in a 49-year-old male patient. The patient sustained a penetrating injury to his right forearm caused by a kitchen knife that was repaired primarily through an emergency surgery under general anesthesia. During the regular follow-up on the 52nd postoperative day, the patient presented 20° of extension lags in the right thumb and index finger and 30° in the small finger. Wrist extension was intact, and there was no sensory deficit. We explored the wound and traced the PIN completely, identifying a club-shaped neuroma formation at the proximal cut end of the PIN. Delayed nerve repair was performed with a double-strip cable graft. Hand surgeons should be aware of the probable PIN injury in certain situations of forearm-penetrating injury and perform proper preoperative physical examination to rule out neurovascular deficits. Careful exploration and immediate repair of severe PIN are mandatory, even in emergency situations.

Security Comparison of Various Surgical Knots Using Nylon Suture.

OBJECTIVE: To evaluate the strengths of various surgical knot techniques, including square knot, surgeon's knot, granny knot, and random knot with the same three throws. METHODS: The authors tested each of the four knot techniques using four different gauges of nylon (polyamide [Ethicon]): 4-0, 5-0, 6-0, and 7-0. Each knot type was tested 20 times per nylon gauge, for a total of 320 knots tested. The authors used a static pull machine to measure elongation at yield and maximal force to break. RESULTS: A comparison of elongation at yield revealed that the surgeon's knot was superior to the square knot, granny knot, and random knots across all gauges of nylons. Further, a comparison of maximal force to break revealed that the surgeon's knot was superior to the square knot, granny knot, and random knots when using 4-0, 5-0, and 6-0 nylon but not when using 7-0 nylon. CONCLUSIONS: The surgeon's knot was the strongest, and random knot was the weakest when the authors used nylon 4-0, 5-0, and 6-0. While handling fine suture materials such as 7-0 nylon, knot failure appears to be unrelated to the knot technique used. This study provides not only fundamental guidance for tying surgical knots using nylon, but also a rational basis for an adequately strong knot choice in various fields of surgery.