Ultra-minimally invasive sonographically guided carpal tunnel release: anatomic study of a new technique.

OBJECTIVES: The purposes of this study were to measure a safe zone and a path for ultra-minimally invasive sonographically guided carpal tunnel release with a 1-mm incision in healthy volunteers and then test the procedure in cadavers. METHODS: First, a previously reported sonographic zone was defined as the space between the median nerve and the closest ulnar vascular structure. Axially, the safest theoretical cutting point for carpal tunnel release was set by bisecting this zone. Magnetic resonance imaging was used for axially determining the limits of the sectors (origin at the cutting point) that did not enclose structures at risk (arteries and nerves) and coronally for determining whether our release path could require directions that could potentially compromise safety (origin at the pisiform's proximal pole). Second, in cadavers, we performed ultra-minimally invasive sonographically guided carpal tunnel release from an intracarpal position through a 1-mm antebrachial approach. Efficacy (deepest fibrous layer release rate), safety (absence of neurovascular or tendon injury), and damage to any anatomy superficial to transverse carpal ligament were assessed by dissection. RESULTS: All 11 of our volunteers (22 wrists) had safe axial sectors located volar and radially of at least 80.4º (considered safe). Release path directions were theoretically safe (almost parallel to the longitudinal axis of the forearm). In 10 cadaver wrists, ultra-minimally invasive sonographically guided carpal tunnel release was effective (100% release rate) and safe without signs of intrusion into the superficial anatomy. CONCLUSIONS: Ultra-minimally invasive sonographically guided carpal tunnel release in a safe sonographic zone may be feasible The technique preserves the superficial anatomy and diminishes the damage of a surgical approach.

Sonographically guided intrasheath percutaneous release of the first annular pulley for trigger digits, part 2: randomized comparative study of the economic impact of 3 surgical models.

OBJECTIVES: Trigger digit surgery can be performed by an open approach using classic open surgery, by a wide-awake approach, or by sonographically guided first annular pulley release in day surgery and office-based ambulatory settings. Our goal was to perform a turnover and economic analysis of 3 surgical models. METHODS: Two studies were conducted. The first was a turnover analysis of 57 patients allocated 4:4:1 into the surgical models: sonographically guided-office-based, classic open-day surgery, and wide-awake-office-based. Regression analysis for the turnover time was monitored for assessing stability (R(2) < .26). Second, on the basis of turnover times and hospital tariff revenues, we calculated the total costs, income to cost ratio, opportunity cost, true cost, true net income (primary variable), break-even points for sonographically guided fixed costs, and 1-way analysis for identifying thresholds among alternatives. RESULTS: Thirteen sonographically guided-office-based patients were withdrawn because of a learning curve influence. The wide-awake (n = 6) and classic (n = 26) models were compared to the last 25% of the sonographically guided group (n = 12), which showed significantly less mean turnover times, income to cost ratios 2.52 and 10.9 times larger, and true costs 75.48 and 20.92 times lower, respectively. A true net income break-even point happened after 19.78 sonographically guided-office-based procedures. Sensitivity analysis showed a threshold between wide-awake and last 25% sonographically guided true costs if the last 25% sonographically guided turnover times reached 65.23 and 27.81 minutes, respectively. However, this trial was underpowered. CONCLUSIONS: This trial comparing surgical models was underpowered and is inconclusive on turnover times; however, the sonographically guided-office-based approach showed shorter turnover times and better economic results with a quick recoup of the costs of sonographically assisted surgery.