金森 大輔

PURPOSE: The purpose of this study was to elucidate the effects of the tongue-hold swallow (THS) on the pharyngeal wall by quantifying posterior pharyngeal wall (PPW) anterior bulge during the THS. In addition, the effect of tongue protrusion length on the extent of pharyngeal wall anterior bulge was analysed. METHODS: Thirteen healthy subjects (6 males and 7 females, 23-43 years) underwent 320-row area detector CT during saliva swallow (SS) and THS at two tongue protrusion lengths (THS1 protrude the tongue as much as 1/3 of premeasured maximum tongue protrusion length (MTP-L) and THS2 protrude the tongue as much as 2/3 of MTP-L). To acquire images of the pharynx at rest, single-phase volume scanning was performed three times during usual breathing with no tongue protrusion (rest), protrusion of the tongue at 1/3 of MTP-L (rTHS1) and protrusion of the tongue at 2/3 of MTP-L (rTHS2). Length from cervical spine to PPW (PPW-AP) and the volume of pharyngeal cavity was measured and was compared between rest, rTHS1 and rTHS2 and between SS, THS1 and THS2. Correlation between MTP-L and PPW-AP was calculated in three conditions, SS, THS1 and THS2. RESULTS: PPW-AP at rest, rTHS1 and rTHS2 was 2.9 ± 0.6 mm, 3.0 ± 0.5 mm and 3.0 ± 0.5 mm, respectively, showing no significant differences across swallows. PPW-AP at the maximum pharyngeal constriction was 8.1 ± 2.0 mm, 9.1 ± 2.4 mm and 8.7 ± 2.0 mm in SS, THS1 and THS2, respectively. Compared to SS, PPW-AP in THS1 was significantly larger (p = 0.04) and PPW-AP in THS2 was not significantly different (p = 0.09). Pharyngeal volume at rest, rTHS1 and rTHS2 was 16.4 ± 5.2 mm3 , 18.4 ± 4.5 mm3 and 21.3 ± 6.2 mm3 , respectively. It was significantly larger during rTHS2 compared with rest or rTHS1 (rTHS2-rest p = 0.007, rTHS2-rTHS1 p = 0.007). Pharyngeal volume was completely obliterated (zero volume) at maximum pharyngeal contraction in all except one subject. There was no correlation between MTP-L and PPW-AP in any of the three conditions (SS, THS1 and THS2). DISCUSSION: This study demonstrated that the expanded pharyngeal cavity due to the tongue protrusion was completely obliterated by the increase in anterior motion of pharyngeal wall during THS. It also became clear that the degree of tongue protrusion did not linearly correlate with the movement of PPW during THS. There was no relationship between PPW motion and the MTP-L, suggesting that the effect of tongue protrusion is better determined in each subject by analysing the motion of PPW using imaging tools.

Objective: Some patients with cleft palate (CP) need secondary surgery to improve functionality. Although 4-dimensional assessment of velopharyngeal closure function (VPF) in patients with CP using computed tomography (CT) has been existed, the knowledge about quantitative evaluation and radiation exposure dose is limited. We performed a qualitative and quantitative assessment of VPF using CT and estimated the exposure doses. Design: Cross-sectional. Setting: Computed tomography images from 5 preoperative patients with submucous CP (SMCP) and 10 postoperative patients with a history of CP (8 boys and 7 girls, aged 4-7 years) were evaluated. Patients: Five patients had undergone primary surgery for SMCP; 10 received secondary surgery for hypernasality. Main Outcome Measures: The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area (CSA) of VPI was evaluated via CT findings. Organ-absorbed radiation doses were estimated in 5 of 15 patients. The differences between cleft type and VPI, VPC patterns, and CSA of VPI were evaluated. Results: All patients had VPI. The VPC patterns (SMCP/CP) were evaluated as coronal (1/4), sagittal (0/1), circular (1/2), and circular with Passavant’s ridge (2/2); 2 patients (1/1) were unevaluable because of poor VPF. The CSA of VPI was statistically larger in the SMCP group (P =.0027). The organ-absorbed radiation doses were relatively lower than those previously reported. Conclusions: Four-dimensional CT can provide the detailed findings of VPF that are not possible with conventional CT, and the exposure dose was considered medically acceptable.

近年，口唇口蓋裂患者に対する二次的顎裂部骨移植術の術後評価に，CT画像を用いた検討が報告されている．われわれは，二次的顎裂部骨移植術による骨架橋容積の評価と，骨架橋成立に寄与する予後規定因子を明らかにするため，CT画像を用いた検討を行ったので報告する．二次的顎裂部骨移植術を行った片側性唇顎裂（unilateral cleft lip and alveolar: UCLA），片側性唇顎口蓋裂児（unilateral cleft lip, alveolar, and palate: UCLP）の各30例，計60例を対象とし，術前後にCT画像を撮影した．骨欠損腔の容積から顎裂部骨架橋率を算出し，その予後規定因子について検討を行った．骨架橋率の中央値は片側性唇顎裂で83.6%，片側性唇顎口蓋裂で66.3%となった．単変量解析，多変量解析双方において，口蓋裂の有無および術前の顎裂部骨欠損腔容積の大きさが有意な予後規定因子として抽出された．顎裂部誘導歯の種類や萌出状況は予後に関連しなかった．