Nathan L. Frost

Indiana Orthopaedic Hospital, Indianapolis, Indiana, United States

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Publications (2)1.47 Total impact

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    ABSTRACT: Background Posterior-only procedures are becoming more popular for treatment of rigid adolescent idiopathic scoliosis, but little is known about the quantitative correction potential for Ponte osteotomies. The objective of this study was to quantify and compare the range of motion of intact multilevel thoracic spine segments with the same segments after each of 3 sequential Ponte osteotomies.Methods We tested 5 human cadaveric thoracic spine segments, spanning T–T6, or T7–T12, in an 8-degree-of-freedom servo-hydraulic load frame, monitoring motion of each vertebra with an optical motion tracker. We measured range of motion while we applied cyclic, pure moment loading to produce flexion-extension, lateral bending, and axial rotation at a rate of 0.5°/second, to a maximum of ± 6 Nm. Each specimen was tested intact and after each of 3 sequential Ponte osteotomies.ResultsTotal range of motion for the segments (either T2–T5 or T8–T11) increased by as much as 1.6° in flexion, 1.5° in extension, 0.5° in lateral bending, and 2.8° in axial rotation with each osteotomy. Because of the variation in initial specimen stiffness, we normalized motions to the intact values. In flexion, average range of motion increased after each osteotomy compared with intact, by 33%, 56%, and 69%. In extension, slightly smaller increases were seen, increasing by as much as 56% after the third osteotomy. In lateral bending, Ponte osteotomies had little effect on range of motion. In axial rotation, range of motion increased by 16%, 29%, and 65% after 3 osteotomies.Conclusions Sequential Ponte osteotomies increased range of motion in flexion, extension, and axial rotation, but not in lateral bending. These results suggest that the Ponte osteotomy may be appropriate when using derotational correction maneuvers, or to improve apical lordosis at the apex of curvature during posterior spinal fusion procedures. Although these techniques are effective in gaining correction for kyphotic deformities and rigid curvatures, they add time and blood loss to the procedure.
    No preview · Article · May 2013
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    ABSTRACT: : The Mitchell-Ponseti (MP) foot abduction orthosis was introduced to provide a more user-friendly alternative to the traditional Denis-Browne (DB) brace in the treatment of idiopathic clubfoot. We describe our experience with the effectiveness of the MP brace to maintain correction of clubfeet corrected using the Ponseti method. : We evaluated 57 consecutive infants with 84 idiopathic clubfeet who were treated using the Ponseti method. After initial correction of the deformity was obtained, all infants were placed in the MP brace. : The patients were followed for a minimum of 2 years (mean, 37.9 mo; range, 24 to 56 mo). Seventy-nine feet (94%) had heel-cord tenotomy or lengthening. The families of 34 (60%) patients were adherent with the postcorrective brace protocol. Skin problems were observed in 8 patients (14%), 6 of which were superficial dorsal skin abrasion, and none of the sandals required customization by an orthotist. A recurrence occurred in 40 feet (48%). Correction was regained with manipulation and cast application in all cases. Nineteen feet (23%) in 14 patients have had, or are scheduled for, an anterior tibial tendon transfer. At latest follow-up, all feet were plantigrade and had at least 10 degrees of dorsiflexion. None of the patients required surgical releases. Of 31 patients followed for at least 3 years, 26 (84%) used the brace for a minimum of 3 years. : Using the MP foot abduction orthosis, we were able to achieve compliance rates that were at least comparable with those of earlier reports using the DB brace. Families found the brace easy to use. The MP brace may be considered a useful alternative to the DB brace. : Level II-prospective.
    No preview · Article · Oct 2012 · Journal of pediatric orthopedics

Publication Stats

20 Citations
1.47 Total Impact Points


  • 2013
    • Indiana Orthopaedic Hospital
      Indianapolis, Indiana, United States