Clustered Volleys Stimulus Presentation for Multifocal Objective Perimetry.

PURPOSE: Multifocal pupillographic objective perimetry (mfPOP) is being developed as an alternative to subjective threshold perimetry for the management of visual and neurological disorders. Here, we evaluate, in normal subjects, differences in signal quality between the original mfPOP method of spatially sparse Continuous stimulus presentation and the new Clustered Volleys (CVs) method. We hypothesized that the CVs method would lead to increased signal-to-noise ratios (SNRs) over the original method due to the stabilization of gain within the pupillary system. METHODS: Data were collected from six separate studies where otherwise-identical pairs of mfPOP tests using either the original Continuous stimulus presentation method or the new CVs method were undertaken; 440 6-minute tests from 96 normal subjects of varying ages were included. Per-region SNRs were compared between the two methods. RESULTS: Mean SNRs for the CVs mfPOP variants were between 35% and 57% larger than the original Continuous mfPOP variants (P < 0.001 in five of six studies). Similarly, the goodness-of-fit measure (r2) demonstrated large and significant fold increases of between 2.3× and 3.4× over the original method (all P < 0.001). Significant improvements in SNRs were present in all of the 88 test regions (44/eye), ranging between 8.4% and 93.7%; mean SNRs were significantly larger in 98% of test subjects. CONCLUSIONS: The CVs mfPOP stimulus presentation method produced substantial increases in signal quality over the original method. This is likely due to the stabilization of pupillary gain during stimulus presentation. TRANSLATIONAL RELEVANCE: These improvements increase diagnostic accuracy and have enabled shorter, 80-second mfPOP tests to be developed.

Radial head fractures: MRI evaluation of associated injuries.

The purpose of this study was to evaluate the incidence of combined osteochondral and ligamentous injuries by magnetic resonance imaging (MRI) in 24 patients with an acute radial head fracture (Mason type II and III) without documented dislocation or tenderness at the distal radioulnar joint. Elbow radiographs (anteroposterior and lateral views) were obtained on all patients as well as magnetic resonance images in the sagittal, coronal, axial, axial oblique, and coronal oblique planes with the injured elbow in a splint. The incidence of associated injuries revealed by MRI was medial collateral ligament not intact in 13 of 24 (54.16%), lateral ulnar collateral ligament not intact in 18 of 24 (80.1%), both collateral ligaments not intact in 12 of 24 (50%), capitellar osteochondral defects in 7 of 24 (29.1%), capitellar bone bruises in 23 of 24 (95.83%), and loose bodies in 22 of 24 (91.67%). A high level of suspicion should be used when one is treating displaced or comminuted radial head fractures, because concurrent osteochondral injuries and/or ligamentous injuries may be present.

Gunshot femoral shaft fractures: is the current classification system reliable?

The reliability of the AO/Orthopaedic Trauma Association classification system has not been evaluated for diaphyseal fractures or fractures attributable to gunshot injuries. Therefore, the current authors assessed its reliability for diaphyseal femur fractures and investigated the effect of a gunshot mechanism of injury. Forty-seven diaphyseal femur fractures, 23 caused by gunshots and 24 caused by blunt trauma, were classified by four observers on two occasions. The interobserver and intraobserver reliability of each level of the AO/Orthopaedic Trauma Association classification was assessed with kappa statistics. Determination of fracture type had substantial interobserver and intraobserver reliability for gunshot and blunt injuries. Reliability decreased at the subsequent levels of the classification. Fractures caused by gunshots compared with those caused by blunt trauma were characterized by significantly lower interobserver agreement on fracture group (k = 0.26 versus 0.45) and subgroup (k = 0.21 versus 0.38). The AO/Orthopaedic Trauma Association classification system has substantial interobserver and intraobserver reliability when evaluating the type of diaphyseal femur fractures. Determination of fracture group and subgroup, however, progressively reduces the reliability of the classification, especially for fractures caused by a gunshot. Diaphyseal femur fractures caused by gunshots, by means of their fracture patterns, cannot be classified reliably with the AO/Orthopaedic Trauma Association classification system.

Analysis of the bicipital groove as a landmark for humeral head replacement.

Many anthropometric studies of the normal glenohumeral relationship have been performed in an effort to identify reference points for the correct placement of the humeral head prosthesis in shoulder arthroplasty. The bicipital groove offers a useful landmark for placement of the lateral fin of the prosthesis. However, when fracture surgery is performed, only the distal portion of the bicipital groove may be available for reference. We evaluated the course of the bicipital groove as it moves distally along the humerus. Computer-assisted tomography axial images of 21 cadaveric humeri were obtained in order to follow the course of the bicipital groove from proximal to distal on the humerus. With use of the bisector of the transepicondylar axis as a reference point, the relative change in position of the bicipital groove from proximal to distal was measured. The mean change in rotation of the lateral lip from the proximal to the distal groove was 15.9 degrees, with an SD of 6.8 degrees (range, 4 degrees -32 degrees ). The 95% confidence interval range for the change was 12.8 degrees to 19 degrees. Thus, a significant amount of internal rotation occurs along the course of the bicipital groove. This has significant clinical implications when the bicipital groove is used as a landmark for humeral head replacement in fractures of the proximal humerus.