Attributing awareness to oneself and to others.

This study tested the possible relationship between reported visual awareness ("I see a visual stimulus in front of me") and the social attribution of awareness to someone else ("That person is aware of an object next to him"). Subjects were tested in two steps. First, in an fMRI experiment, subjects were asked to attribute states of awareness to a cartoon face. Activity associated with this task was found bilaterally within the temporoparietal junction (TPJ) among other areas. Second, the TPJ was transiently disrupted using single-pulse transcranial magnetic stimulation (TMS). When the TMS was targeted to the same cortical sites that had become active during the social attribution task, the subjects showed symptoms of visual neglect in that their detection of visual stimuli was significantly affected. In control trials, when TMS was targeted to nearby cortical sites that had not become active during the social attribution task, no significant effect on visual detection was found. These results suggest that there may be at least some partial overlap in brain mechanisms that participate in the social attribution of sensory awareness to other people and in attributing sensory awareness to oneself.

Complex organization of human primary motor cortex: a high-resolution fMRI study.

A traditional view of the human motor cortex is that it contains an overlapping sequence of body part representations from the tongue in a ventral location to the foot in a dorsal location. In this study, high-resolution functional MRI (1.5x1.5x2 mm) was used to examine the somatotopic map in the lateral motor cortex of humans, to determine whether it followed the traditional somatotopic order or whether it contained any violations of that somatotopic order. The arm and hand representation had a complex organization in which the arm was relatively emphasized in two areas: one dorsal and the other ventral to a region that emphasized the fingers. This violation of a traditional somatotopic order suggests that the motor cortex is not merely a map of the body but is topographically shaped by other influences, perhaps including correlations in the use of body parts in the motor repertoire.

Over-pointing technique: an approach to past-pointing arthroscopic knots on alternating suture posts without alternating the knot pusher.

As arthroscopic reconstructive surgery evolves, new techniques that improve operative efficiency while maintaining proven technical principles will enhance a surgeon's skill repertoire. A secure arthroscopic knot requires placing a series of reversed half-hitches on alternating posts and has traditionally involved alternating the knot-passing device between suture limbs to "past-point" each half-hitch, ensuring overall knot security. To increase the speed of knot-tying, a technical variation of keeping the knot pusher on the same suture limb throughout the knot-tying process, while still alternating posts, can be used. This technique involves alternately "pushing" and "pulling" sequential half-hitches into place. It is important to note that although conventional past-pointing is performed when "pulling" a half-hitch, it cannot be performed when purely "pushing" a half-hitch. In this article we describe a novel technique of "over-pointing" to be performed when pushing half-hitches into place. This is meant to be a complement to past-pointing by use of the knot pusher to advance the half-hitch and tighten the knot by over-riding the knot, effectively providing the equivalent of past-pointing by "pulling" the knot tight. In this way, a knot can be constructed without removing the device from the initial post strand of suture, saving time while maintaining the principles of secure knot-tying.

The effect of double-row fixation on initial repair strength in rotator cuff repair: a biomechanical study.

PURPOSE: The purpose of this study was to compare the initial mechanical strength of 3 rotator cuff repair techniques. METHODS: A total of 30 fresh-frozen cadaveric shoulders were prepared, and full-thickness supraspinatus tears were created. Specimens were randomized and placed into 3 groups: (1) transosseous suture technique (group I: TOS, n = 10, 6F/4M), (2) single-row suture anchor fixation (group II: SRSA, n = 10, 6F/4M), and (3) double-row suture anchor fixation (group III: DRSA, n = 10, 6F/4M). Each specimen underwent cyclic load testing from 5 N to 180 N at a rate of 33 mm/sec. The test was stopped when complete failure (repair site gap of 10 mm) or a total of 5,000 cycles was attained. RESULTS: Group I (TOS) failed at an average of 75.3 +/- 22.49 cycles, and group II (SRSA) at an average of 798.3 +/- 73.28 cycles; group III (DRSA) had no failures because all samples were stopped when 5,000 cycles had been completed. Fixation strength of the DRSA technique proved to be significantly greater than that of SRSA (P < .001), and both suture anchor groups were significantly stronger than the TOS group (P < .001). CONCLUSIONS: Suture anchor repairs were significantly stronger than transosseous repairs. Furthermore, double-row suture anchor fixation was significantly stronger than was single-row repair. Therefore, double-row fixation may be superior to other techniques in that it provides a substantially stronger repair that could lead to improved biologic healing. CLINICAL RELEVANCE: A high incidence of incomplete healing occurs in rotator cuff repair. Use of double-row fixation may help the clinician to address some deficiencies in current methods by increasing the strength of the repair, potentially leading to improved healing rates.

Rotator cuff repair: the effect of double-row fixation on three-dimensional repair site.

There is a high rate of recurrent and residual tears after rotator cuff repair surgery. Recent cadaveric studies have provided surgeons with new knowledge about the anatomy of the supraspinatus tendon insertion. Traditional repair techniques fail to reproduce the area of the supraspinatus insertion, or footprint, on the greater tuberosity anatomically. Double-row suture anchor (DRSA) fixation is a new technique that has been developed to restore the supraspinatus footprint better. In this study, 3-dimensional mapping was used to determine the area of the footprint recreated with 3 different repair methods: a transosseous simple suture technique, fixation with a single row of suture anchors, and DRSA fixation. The DRSA fixation technique consistently reproduced 100% of the original supraspinatus footprint, whereas the single-row suture anchor fixation and transosseous simple suture techniques reproduced only 46% and 71% of the insertion site, respectively. Therefore, the footprint area of the DRSA fixation technique was significantly larger (P < .05) than that of the other 2 techniques. Furthermore, double-row fixation may provide a tendon-bone interface better suited for biologic healing and restoring normal anatomy.