Measurement of blood flow in the rotator cuff using laser Doppler flowmetry

Abstract

The aim of this study was to define the microcirculation of the normal rotator cuff during arthroscopic surgery and investigate whether it is altered in diseased cuff tissue. Blood flow was measured intra-operatively by laser Doppler flowmetry. We investigated six different zones of each rotator cuff during the arthroscopic examination of 56 consecutive patients undergoing investigation for impingement, cuff tears or instability; there were 336 measurements overall. The mean laser Doppler flowmetry flux was significantly higher at the edges of the tear in torn cuffs (43.1, 95% confidence interval (CI) 37.8 to 48.4) compared with normal cuffs (32.8, 95% CI 27.4 to 38.1; p = 0.0089). It was significantly lower across all anatomical locations in cuffs with impingement (25.4, 95% CI 22.4 to 28.5) compared with normal cuffs (p = 0.0196), and significantly lower in cuffs with impingement compared with torn cuffs (p < 0.0001). Laser Doppler flowmetry analysis of the rotator cuff blood supply indicated a significant difference between the vascularity of the normal and the pathological rotator cuff. We were unable to demonstrate a functional hypoperfusion area or so-called 'critical zone' in the normal cuff. The measured flux decreases with advancing impingement, but there is a substantial increase at the edges of rotator cuff tears. This might reflect an attempt at repair.

Microvascular blood flow in normal and pathologic rotator cuffs

“…4,19,30 However, since Codman 6 described a watershed area in the rotator cuff, there is debate as to whether there is a ''critical area'' of relative avascularity in the supraspinatus tendon, just proximal to its bony insertion, that makes it vulnerable to tendinopathy and eventual tears. 8,[17][18][19]22,28,30,34,35 The presence of a critical zone is primarily supported by in vitro studies. 8,18,19,28,30 Most of these studies involved injecting a hardening substance and analyzing resultant tissues by histologic techniques.…”

“…Recent studies using in vivo physiologic techniques, such as doppler ultrasound and laser doppler flowmetry (LDF), have failed to support the presence of a critical zone in the rotator cuff. 12,17,34,35 However, these studies were limited by small sample sizes and inefficient analyses. Also, the pattern of blood flow around a partial-thickness tear has not previously been studied as a separate group.…”

Surgical Technique to Repair Musculotendinous Junction Tear of Supraspinatus Using Lateral-Row Anchors to Avoid Cut-Through

“…9 In another study regarding the vascularity of torn tendons, it was found that there was a substantial increase in vascularity at the edges of rotator cuff tears. 10 This might reflect an attempt at repair.…”

The Histological Analysis of the Glenohumeral "Critical Zone"

“…Subsequently, authors have described it as being hypovascular (Codman;Macnab, 1973;Lohr & Uhthoff, 1990;Brooks et al, 1992;Determe et al, 1996;Kane et al, 2006;Adler et al, 2008;Levy et al, 2008), avascular (Rathburn & Macnab;Herberts et al, 1981;Ling et al, 1990;Chansky & Iannotti) or hypervascular (Seitz et al) (Table I). Barr (2004) postulated avascularity to arise from the compression and attrition of the supraspinatus tendon in a narrowed subacromial space.…”