Mohammad Kamal

Bony contact area and displacement of the temporomandibular joint after high-oblique and bilateral sagittal split osteotomy: a computer-simulated comparison.

The most common way to move the mandible during orthognathic surgery is by bilateral sagittal split osteotomy (BSSO). The high-oblique sagittal split osteotomy (HSSO) is an alternative, although its use is limited by potential complications, mainly to do with the position of the condyle and reduced contact with bone. The aim of this study was to find out the optimal intercondylar distance and area of contact with the surface of the bone for mandibular advancement and setback in BSSO and HSSO. Data from computed tomographic (CT) images from 40 patients were loaded into special planning software, and virtual operations done for mandibular advancement and setback at 3, 5, 8, and 10mm using BSSO and HSSO, which resulted in 640 individual mandibular displacements. The resultant area of bony contact and intercondylar distance were calculated by the software. The mean (SD) areas of contact with the bony surface after 10mm advancement for HSSO and BSSO were 193.94 (63.76) mm(2) and 967.92 (229.21) mm(2), respectively, and after 10mm setback 202.64 (62.30) mm(2) and 1108.86 (247.38) mm(2). The mean corresponding intercondylar distance after maximum advancement were 86.76 (6.40) mm and 86.59 (6.24) mm, and after maximum setback 74.90 (5.73) mm and 73.06 (6.06) mm. There were significant differences between the two for the area of contact with the surface at each displacement distance (p<0.001), but not for intercondylar distance. A larger area of bony contact can be expected at any displacement distance for BSSO, so the changes in intercondylar distance should not be considered when deciding which osteotomy to select.

Hand Perfusion in Patients with Physiological or Pathological Allen's Tests

Background The Allen test (AT) is a widely used clinical tool for the preoperative assessment of sufficient dual vessel hand perfusion although the impact of a pathological AT on tissue perfusion of the hand is not entirely clear. This study reveals perfusion changes of the hand in patients with pathological and physiological AT after terminating the dual blood supply. Methods Patients were distributed into 2 groups (physiological and pathological AT) that each contained 25 members. Perfusion of the thumb, middle, and small fingers was measured with a laser Doppler based (“oxygen‐to‐see” [O2C]) device. A steady state was measured and also values at 1, 3, 5, and 10 minutes after radial occlusion were measured. Results In patients with a physiological AT, only 1 out of 18 values differed significantly from the steady state measurements after 10 minutes, whereas patients with a pathological AT showed significant alterations in 8 out of 18 values. Oxygen saturation of the superficial and deep tissues appeared to be significantly worse in patients with a pathological AT. Conclusion Patients with a pathological AT suffered significantly more from the loss of dual hand perfusion than patients with a physiological AT. Patients with a pathological AT need more time to compensate for the altered perfusion pattern.