Validation of a simple computerized tool for measuring spinal and pelvic parameters.

OBJECT: Recent studies have emphasized measuring the sagittal vertical axis (SVA) and pelvic parameters (pelvic incidence, sacral slope, and pelvic tilt) when evaluating spinal disorders. An accurate and reproducible measurement is important for a reliable result. Although computerized measurement is more consistent than manual measurement, computerized measurement requires an expensive software program, the need to transfer images to a workstation, and additional education for users. An inexpensive and convenient computerized measurement program is desirable and necessary. The object of this study was to propose a computerized tool for measuring spinal and pelvic parameters and to evaluate the efficacy of this new tool compared with manual measurement. METHODS: The authors devised a tool that provides computerized measurements of the SVA and pelvic parameters in a picture archiving and communication system (PACS) without transferring images to another program. This tool was created by merging functions in the PACS. The resulting tool is easy to implement by merging functions (indicate the center of 2 points, plot a vertical and a horizontal line from a point, and measure the angles between lines) in any image viewer. The tool was made into icons on a toolbar in the PACS. Measurements of distance and angle were computerized by identifying crucial points after selecting the icon. For SVA, 4 points were identified around each corner of the C-7 body and a fifth point at the superior/posterior corner of the S-1 body. For pelvic parameters, 4 points were identified at the centers of each femoral head and at the anterior/superior and posterior/superior corners of S-1. Thirty-three whole-spine lateral radiographs were randomly selected from the radiographic database. To evaluate inter- and intraobserver variability between observers and method, skilled (2 years of experience) and unskilled (1 week of experience) observers measured SVA and pelvic parameters 3 times with a 7-day interval between each time using both computerized and manual measurement methods. The reliability was measured using the intraclass correlation coefficient. RESULTS: The computerized method showed better congruity than the manual method in both skilled and unskilled observers (p < 0.05), and the intraclass correlation coefficients were > 0.9. The skilled observer showed better agreement than the unskilled observer with both computerized and manual methods, and this difference was prominent in measuring pelvic parameters (p < 0.05). The computerized method required less time than the manual method, especially for the unskilled observer (p < 0.05). CONCLUSIONS: A computerized measurement of pelvic parameters may be a more reliable and efficacious approach than manual measurements. This benefit is more prominent in the unskilled observer, and adding this simple function to an image viewer may be recommended in future studies.

Intramuscular nerve distribution of the masseter muscle as a basis for botulinum toxin injection.

The aim of this study was to determine intramuscular distribution pattern of the masseteric nerve, thus providing information regarding the most efficient and safe site for botulinum toxin (BTX) injection for conventional BTX intervention therapy in the treatment of masseteric hypertrophy.Twelve masseter muscles were dissected, and the pattern of innervation of the masseteric nerve was observed in the superficial, middle, and deep layers. We also analyzed 10 muscles that had been stained using Sihler's staining technique.The nerve branches from the posterosuperior and posteroinferior groups innervating the deep and middle layers of the masseter muscle, respectively. Among the nerve twigs originating from the anteroinferior nerve group, 2 or 3 perforated the superficial layer of the muscle. Observation of stained specimens revealed that all perforating branches innervating the superficial layer were mainly confined to and distributed within areas V or VI.Between 2 and 4 perforating branches supply the superficial layer of the masseter muscle. In addition, the richest arborization of the perforating masseteric nerve branches is confined mostly to area V, approximately in accordance with the BTX injection point that is currently used clinically. Area V is thus strongly recommended as the most efficient and safe BTX injection area for the treatment of masseteric hypertrophy.