Malcolm Birch

Palate re-repair revisited.

OBJECTIVEnTo analyze the results of a consecutive series of palate re-repairs performed using the operating microscope and identify predictive factors for outcome.nnnDESIGNnProspective data collection, with blind assessment of randomized recordings of speech and velar function on lateral videofluoroscopy and nasendoscopy.nnnPATIENTSnOne hundred twenty-nine consecutive patients with previously repaired cleft palates and symptomatic velopharyngeal incompetence (VPI) and evidence of anterior insertion of the levator veli palatini underwent palate re-repairs by a single surgeon from 1992 to 1998. Syndromic patients, those who had significant additional surgical procedures at the time of re-repair (23 patients), and all patients with inadequate pre- or postoperative speech recordings were excluded, leaving a total of 85 patients in the study.nnnINTERVENTIONSnPalate re-repairs, with radical dissection and retropositioning of the velar muscles, were performed using the operating microscope with intraoperative grading of anatomical and surgical findings.nnnMAIN OUTCOME MEASURESnPre- and postoperative perceptual speech assessments using the Cleft Audit Protocol for Speech (CAPS) score, measurement of velar function on lateral videofluoroscopy, and assessment of nasendoscopy recordings.nnnRESULTSnThere were significant improvements in hypernasality, nasal emission, and nasal turbulence and measures of velar function on lateral videofluoroscopy, with improvement in the closure ratio, velopharyngeal gap at closure, velar excursion, velar movement angle, and velar velocity.nnnCONCLUSIONSnPalate re-repair has been shown to be effective in treating VPI following cleft palate repair, both in patients who have not had an intravelar veloplasty and those who have had a previous attempt at muscle dissection and retropositioning. Palate re-repair has a lower morbidity and is more physiological than a pharyngoplasty or pharyngeal flap.

Cleft palate re-repair—a clinical and radiographic study of 32 consecutive cases

The results of clinical and radiographic assessment of palate re-repair (by a single operator) in 32 patients are presented. This has shown that radical muscle correction as a secondary procedure (following limited or no muscle correction in primary repair) has produced measurable improvement in velar function and should be considered as the first option in many patients with velopharyngeal incompetence. The results also support the concept of muscle dissection and retropositioning in primary cleft palate repair.

Surgical management of velopharyngeal incompetence in velocardiofacial syndrome

Objective To analyze the results of surgery for velopharyngeal incompetence (VPI) in velocardiofacial syndrome. Design Prospective data collection, with randomized, blind assessment of speech and velopharyngeal function on lateral videofluoroscopy and nasendoscopy. Setting Two-site, tertiary referral cleft unit. Patients Forty-two consecutive patients with the 22q11 deletion underwent surgery for symptomatic VPI by a single surgeon. Interventions Intraoral examinations, lateral videofluoroscopy (± nasendoscopy) and intraoperative evaluation of the position of the velar muscles through the operating microscope. Based on these findings, either a radical dissection and retropositioning of the velar muscles (submucous cleft palate [SMCP repair]) or a Hynes pharyngoplasty (posterior pharyngeal wall augmentation pharyngoplasty) was performed. As anticipated, a proportion of patients undergoing SMCP repair subsequently required a Hynes. The aim of this staged approach was to maximize velar function, thereby enabling a less obstructive pharyngoplasty to be performed. Thus, there were three surgical groups for analysis: SMCP alone, Hynes alone, and SMCP+Hynes. Main Outcome Measures Blind perceptual rating of resonance and nasal airflow; blind assessment of velopharyngeal function on lateral videofluoroscopy and nasendoscopy; and identification of predictive factors. Results Significant improvement in hypernasality in all three groups. The SMCP+Hynes group also showed significant improvement in nasal emission. There were significant improvements in the extended and resting velar lengths following SMCP repair and a trend toward increased velocity of closure. Conclusions Depending on velopharyngeal anatomy and function, there is a role for SMCP repair, Hynes pharyngoplasty, and a staged combination of SMCP+Hynes, all of which are procedures with a low morbidity.

Measurement of physiological recovery from exacerbation of chronic obstructive pulmonary disease using within-breath forced oscillometry

Background: Within-breath reactance from forced oscillometry estimates resistance via its inspiratory component (Xrs,insp) and flow limitation via its expiratory component (Xrs,exp). Aim: To assess whether reactance can detect recovery from an exacerbation of chronic obstructive pulmonary disease (COPD). Method: 39 subjects with a COPD exacerbation were assessed on three occasions over 6 weeks using post-bronchodilator forced oscillometry, arterial blood gases, spirometry including inspiratory capacity, symptoms and health-related quality of life (HRQOL). Results: Significant improvements were seen in all spirometric variables except the ratio of forced expiratory volume in 1 s (FEV1) to vital capacity, ranging in mean (SEM) size from 11.0 (2.2)% predicted for peak expiratory flow to 12.1 (2.3)% predicted for vital capacity at 6 weeks. There was an associated increase in arterial partial pressure of oxygen (PaO2). There were significant mean (SEM) increases in both Xrs,insp and Xrs,exp (27.4 (6.7)% and 37.1 (10.0)%, respectively) but no change in oscillometry resistance (Rrs) values. Symptom scales and HRQOL scores improved. For most variables, the largest improvement occurred within the first week with spirometry having the best signal-to-noise ratio. Changes in symptoms and HRQOL correlated best with changes in FEV1, PaO2 and Xrs,insp. Conclusions: The physiological changes seen following an exacerbation of COPD comprised both an improvement in operating lung volumes and a reduction in airway resistance. Given the ease with which forced oscillometry can be performed in these subjects, measurements of Xrs,insp and Xrs,exp could be useful for tracking recovery.

Biomechanical properties of the human soft palate.

Objective: To measure biomechanical properties of the human soft palate and the variation across anatomic regions. Design: Ex vivo analysis of human tissue. Patients/participants: Ten palates harvested from 10 normal adult human cadavers (age range, 37 to 90 years). Interventions: Computer-controlled uniaxial stress-relaxation mechanical properties tested in physiological saline at 37°C. Main Outcome Measures: Measurement of Young modulus, Poisson ratio, and determination of viscoelastic constants c, τ1, and τ2 by curve-fitting of the reduced relaxation function to the data. Results: One hundred sections were tested from the 10 palates, representative of 10 anatomic zones. The mean Young modulus range was 585 Pa at the posterior free edge to 1409 Pa at regions of attachment. The mean Poisson ratio in the inferior-superior direction was 0.45 (SD 0.26) and in the lateral direction, was 0.30 (SD 0.21). The mean viscoelastic constants for 1-mm extensions were C u200a=u200a −0.1056 (±0.1303), τ1 u200a=u200a 11.0369 (±9.1865) seconds, and τ2 u200a=u200a 0.2128 (±0.0792) seconds, and for 2-mm extensions were C u200a=u200a −0.1111 (±0.1466), τ1 u200a=u200a 14.3725 (±5.2701) seconds, and τ2 u200a=u200a 0.2094 (±0.0544) seconds. Conclusions: The results show agreement with values of the Young modulus estimated by authors (Ettema and Kuehn, 1994; Berry et al., 1999) undertaking finite element modeling of the palate. However, other modulus measurements based on closing pressure are considerably different. The spatial distribution of viscoelastic parameters across the palate shows good consistency.

Use of reactance to estimate transpulmonary resistance

This study examines the relationship of respiratory system resistance (Rrs) and reactance (Xrs) measured by forced oscillometry with transpulmonary resistance (RL) measured by oesophageal manometry. Simultaneous forced oscillometry using a single frequency of 5u2005Hz and oesophageal manometry were performed on five asthmatics during bronchoprovocation. The data obtained were used to derive prediction equations for RL from oscillometric parameters, which were tested on a further six asthmatics and 35 nonasthmatic subjects. In the first five asthmatic subjects, RL correlated more strongly with Xrs than with Rrs. In the second set of asthmatics, RL ranged 0.0005–4.57u2005kPa·s·L−1, with a median of 0.21u2005kPa·s·L−1. The RL values predicted from Xrs showed a mean±sd difference of −0.067±0.25u2005kPa·s·L−1 compared with the values measured in this set of patients. Xrs in subjects with other respiratory conditions appeared to follow the same relationship with RL as in asthmatics. Lumped element modelling suggested that the linear relationship between Xrs and RL was a consequence of the increasing contribution of central and upper airway wall shunts as peripheral airway resistance rose, and that this effect was much larger than that due to changes in static elastance. In conclusion, the reactance of the respiratory system can predict transpulmonary resistance more accurately than can the resistance of the respiratory system.

Design of a microwave system for endoscopy: An experimental study of energy, tissue contact, and hemostatic efficacy

BACKGROUNDnA microwave generator and delivery system for endoscopic use was built. Using a 650-W, 2450-MHz magnetron, 0-160 W were generated from the tip of a 180-cm flexible coaxial cable (2.1 mm diameter).nnnMETHODSnThree methods of achieving hemostasis with microwaves were identified studying standard bleeding canine ulcers: (1) interstitial method: inserting the coaxial tip into the tissue and heating slowly until bleeding stopped; (2) contact method: tip held in contact, light pressure applied; (3) noncontact method: microwave-induced sparking (dielectric breakdown) with tip held 1 mm from tissue.nnnRESULTSnStudies of optimal energy levels for hemostasis showed that high power (70 W) noncontact methods required significantly less energy to stop bleeding than contact or interstitial methods. The noncontact method was more effective than the contact method, stopping 20 of 20 bleeding ulcers vs. 10 of 20 (P < 0.001) and was more rapidly effective causing less tissue damage (P < 0.05) than the interstitial method.nnnCONCLUSIONSnIn a randomized comparison using a non-contact method, microwave coagulation was superior (P < 0.001) to a polidocanol 1% + adrenaline 1:10,000 injection and control treatment stopping 40 of 40 vs. 0 of 20 and 0 of 20 standard bleeding ulcers. Microwaves stopped bleeding from 10 of 10 severed mesenteric vessels, whereas injection was ineffective (0 of 10, P < 0.001). Microwaves look promising for hemostasis at flexible endoscopy.

Image analysis of lateral velopharyngeal closure in repaired cleft palates and normal palates

We have undertaken the design and testing of a system for making measurements of velopharyngeal function from lateral videofluoroscopic images based upon standard equipment found in any cleft clinic. The uncertainties in the measurements have been found to be acceptably low and, in conjunction with other measurement techniques, the system has made a valuable contribution to the assessment of velopharyngeal function. Additional measurements using this system are presently being developed.

Palate Lengthening by Buccinator Myomucosal Flaps for Velopharyngeal Insufficiency

Objective To assess the outcome of palate lengthening by myomucosal buccinator flaps for velopharyngeal insufficiency both in terms of speech and changes in palate length. Design Thirty-two consecutive patients who underwent the buccinator flap procedure were reviewed retrospectively. Palate length and the presence or absence of a velopharyngeal gap were assessed on pre- and postoperative videofluoroscopic recordings using a calibrated image analysis system. Hypernasality, nasal emission, nasal turbulence, and passive cleft type articulation errors were evaluated blindly by a speech-language pathologist external to the team using pre- and postoperative speech recordings. Setting Multidisciplinary cleft team based in a tertiary referral center. Results In 81% of patients, speech outcome was such that no further velopharyngeal surgery was considered necessary at the time of follow-up. The buccinator flap procedure resulted in a mean palate lengthening of 7.5 mm (±5.5 SD). After the operation, there was a complete elimination of the velopharyngeal gap on lateral videofluoroscopy in 77% of patients. There were significant decreases in hypernasality ratings and passive cleft type articulation errors postoperatively. Conclusion Palatal lengthening with myomucosal buccinator flaps in patients with velopharyngeal insufficiency is effective and safe. It has become one of our routinely practiced procedures for velopharyngeal insufficiency.

Nasendoscopy: an analysis of measurement uncertainties.

Objective The purpose of this study was to analyze the optical characteristics of two different nasendoscopes used to assess velopharyngeal insufficiency and to quantify the measurement uncertainties that will occur in a typical set of clinical data. Design The magnification and barrel distortion associated with nasendoscopy was estimated by using computer software to analyze the apparent dimensions of a spatially calibrated test object at varying object-lens distances. In addition, a method of semiquantitative analysis of velopharyngeal closure using nasendoscopy and computer software is described. To calculate the reliability of this method, 10 nasendoscopy examinations were analyzed two times by three separate operators. The measure of intraoperator and interoperator agreement was evaluated using Pearsons r correlation coefficient. Results Over an object lens distance of 9 mm, magnification caused the visualized dimensions of the test object to increase by 80%. In addition, dimensions of objects visualized in the far-peripheral field of the nasendoscopic examinations appeared approximately 40% smaller than those visualized in the central field. Using computer software to analyze velopharyngeal closure, the mean correlation coefficient for intrarater reliability was .94 and for interrater reliability was .90. Conclusion Using a custom-designed apparatus, the effect object-lens distance has on the magnification of nasendoscopic images has been quantified. Barrel distortion has also been quantified and was found to be independent of object-lens distance. Using computer software to analyze clinical images, the intraoperator and interoperator correlation appears to show that ratio-metric measurements are reliable.