In Search of the Optimal Surgical Treatment for Velopharyngeal Dysfunction in 22q11.2 Deletion Syndrome: A Systematic Review

<div><h3>Background</h3><p>Patients with the 22q11.2 deletion syndrome (22qDS) and velopharyngeal dysfunction (VPD) tend to have residual VPD following surgery. This systematic review seeks to determine whether a particular surgical procedure results in superior speech outcome or less morbidity.</p> <h3>Methodology/ Principal Findings</h3><p>A combined computerized and hand-search yielded 70 studies, of which 27 were deemed relevant for this review, reporting on a total of 525 patients with 22qDS and VPD undergoing surgery for VPD. All studies were levels 2c or 4 evidence. The methodological quality of these studies was assessed using criteria based on the Cochrane Collaboration's tool for assessing risk of bias. Heterogeneous groups of patients were reported on in the studies. The surgical procedure was often tailored to findings on preoperative imaging. Overall, 50% of patients attained normal resonance, 48% attained normal nasal emissions scores, and 83% had understandable speech postoperatively. However, 5% became hyponasal, 1% had obstructive sleep apnea (OSA), and 17% required further surgery. There were no significant differences in speech outcome between patients who underwent a fat injection, Furlow or intravelar veloplasty, pharyngeal flap pharyngoplasty, Honig pharyngoplasty, or sphincter pharyngoplasty or Hynes procedures. There was a trend that a lower percentage of patients attained normal resonance after a fat injection or palatoplasty than after the more obstructive pharyngoplasties (11–18% versus 44–62%, p = 0.08). Only patients who underwent pharyngeal flaps or sphincter pharyngoplasties incurred OSA, yet this was not statistically significantly more often than after other procedures (p = 0.25). More patients who underwent a palatoplasty needed further surgery than those who underwent a pharyngoplasty (50% versus 7–13%, p = 0.03).</p> <h3>Conclusions/ Significance</h3><p>In the heterogeneous group of patients with 22qDS and VPD, a grade C recommendation can be made to minimize the morbidity of further surgery by choosing to perform a pharyngoplasty directly instead of only a palatoplasty.</p> </div

A MÖSSBAUER STUDY OF THE ELECTRIC HYPERFINE INTERACTION IN K3Fe(CN)6 USING POLARIZED GAMMA RADIATION

On applique le formalisme de la matrice densité à l'étude Mössbauer de monocristaux de K3Fe(CN)6 avec une source polarisée linéairement : l'interprétation des spectres permet de déterminer le Hamiltonien hyperfin électrique moyen du noyau Mössbauer. Les résultats expérimentaux sont donnés pour le noyau 57Fe dans les polytypes monoclinique et orthorhombique, les paramètres hyperfins et les orientations des axes principaux variant selon les polytypes. Les deux polytypes étudiés présentent plusieurs sites de réseau inéquivalents mais énergétiquement indiscernables ; dans un cas, un essai a été fait pour les distinguer. Quelques limitations et des améliorations possibles de la précision sont aussi discutées.The density matrix formalism is applied to the interpretation of Mössbauer spectra of single crystals of K3Fe(CN)6 taken with polarized γ-radiation to find the average electric hyperfine Hamiltonian of the Mössbauer nucleus. Experimental results are given for 57Fe nuclei in the monoclinic and orthorhombic polytypes. The hyperfine parameters and the orientations of the principal axes vary from one polytype to another. Both polytypes investigated show evidence for more than one inequivalent lattice site, although they are not energetically distinguishable, and an attempt is made in one case to resolve the sites. Some limitations and possible improvements of the accuracy are also discussed