Is the frequent sonographic anechoic area distally in metacarpophalangeal joints a sign of arthritis?

In clinical practice, ultrasonography (US) often reveals, in the dorsal scan, a small anechoic area distally in both inflamed and clinically non-inflamed metacarpophalangeal joints. This "distal anechogenicity in the metacarpophalangeal joint" (DAEM) might thus be scored false positively as arthritis. We aimed to investigate whether the DAEM is a sign of arthritis. We evaluated the prevalence of DAEMs in 24 non-arthritic subjects. We then compared the dimensions of the DAEM in 10 non-arthritic subjects with a DAEM and 7 consecutive rheumatoid arthritis (RA) outpatients, using 2-D and 3-D ultrasound. Furthermore, we dissected two fresh-frozen postmortem hand specimens after US. A DAEM was observed in the metacarpophalangeal 2 (MCP2) joints of 54% of the 24 non-selected non-arthritic individuals; in none of those did the joint exhibit a power Doppler signal. A DAEM was observed in 86% of the 7 RA patients. Dimensions of DAEMs did not statistically significantly differ between these groups. At 3-D imaging and dissection, the DAEM was found to be an extension of the metacarpophalangeal joint capsule. In conclusion, DAEMs occur frequently and are not a sign of arthritis, but are distal joint recesses. This should be taken into account when using current sensitive ultrasonographic scoring systems grading arthritis.

Riolan's arch: confusing, misnomer, and obsolete. A literature survey of the connection(s) between the superior and inferior mesenteric arteries.

BACKGROUND: There are 2 interpretations of Riolan's arch: (1) Riolan's arch is identical to a central part of the marginal artery (MA), connecting the superior (SMA) and the inferior mesenteric (IMA) arteries; and (2) Riolan's arch represents a rare artery, connecting the SMA and the IMA. The current review aims to emphasize the clinical importance of the colon's vasculature and to show the feasibility of abolishing the terms "Riolan's arch" and "meandering mesenteric artery." METHODS: A literature survey was performed. RESULTS: It appears that no distinct identity can be ascribed to Riolan's arch and that the "meandering mesenteric artery" represents an angiographically hypertrophied MA and/or the ascending branch of the left colic artery. However, a rare, centrally located, communicating artery has been described. Generally, the MA is sufficient for left colic circulation after ligation of the IMA, but at the splenic flexure, patency of the ascending branch of the left colic artery can be primordial. CONCLUSION: As connections between the SMA and the IMA can be adequately described using structures mentioned in Terminologica Anatomica, the terms "Riolan's arch" and "meandering mesenteric artery" should be abolished.

Creep behavior of commonly used suture materials in abdominal wall surgery.

BACKGROUND: The incidence of incisional hernia after abdominal wall closure is high. Furthermore, recurrence is a significant complication after correction of all abdominal wall hernias. Besides surgeon- and patient-related factors, in this experimental study a third factor, i.e., creep behavior of suture materials, is introduced and evaluated. MATERIALS AND METHODS: Creep measurements were performed on 0 and 2-0 Prolene (Ethicon, Johnson & Johnson Intl., Somerville, NJ) and 1 and 2-0 PDSII (Ethicon, Johnson & Johnson Intl.) sutures. Two different loads were used representing normal intra-abdominal pressure (IAP) and pathological IAP. A mean percentage of elongation was calculated for each type of suture material. Statistical analysis was performed using analysis of variance. RESULTS: All suture materials showed significant (3-51%) creep behavior. Prolene sutures showed more creep than PDSII sutures in both loading conditions. CONCLUSIONS: As significant creep was demonstrated for commonly used suture materials, creep might be a significant influential factor with regard to the etiology of incisional hernias and recurrence after abdominal wall hernia repair.

Functional aspects of cross-legged sitting with special attention to piriformis muscles and sacroiliac joints.

BACKGROUND: Transversely oriented pelvic muscles such as the internal abdominal oblique, transversus abdominis, piriformis and pelvic floor muscles may contribute to sacroiliac joint stability by pressing the sacrum between the hipbones. Surface electromyographic measurements showed that leg crossing lowers the activity of the internal oblique abdominal muscle significantly. This suggests that leg crossing is a substitute for abdominal muscle activity. No previous studies addressed piriformis muscle and related pelvic structures in cross-legged sitting. METHODS: Angles of pelvis and femur were measured in healthy subjects in standing, normal sitting and cross-legged sitting, and were used to simulate these postures on embalmed pelvises and measure piriformis muscle elongation. Deformations of pelvic ring and iliolumbar ligament caused by piriformis muscle force were measured on embalmed pelvises. FINDINGS: Cross-legged sitting resulted in a relative elongation of the piriformis muscle of 11.7% compared to normal sitting and even 21.4% compared to standing. Application of piriformis muscle force resulted in inward deformation of the pelvic ring and compression of the sacroiliac joints and the dorsal side of the pubic symphysis. INTERPRETATION: Cross-legged sitting is common. We believe that it contributes to sacroiliac joint stability. This study demonstrates the influence of the piriformis muscle on sacroiliac joint compression. The elongation of the piriformis muscle bilaterally by crossing the legs may be functional in the build-up of active or passive tension between sacrum and femur.