Circular Closure Research Articles

Quantification of dynamic velopharyngeal port excursion following sphincter pharyngoplasty.

The sphincter pharyngoplasty is a surgical procedure designed to correct velopharyngeal dysfunction. Its advocates cite the theoretical advantage of its induction of dynamic activity of the neovelopharyngeal port, but this dynamic activity has yet to be quantitatively demonstrated in the literature. The purpose of this study was to quantify postoperative velopharyngeal dynamism and to document the results of intervention outcome on sphincteric excursion measurements from minimal-to-maximal orifice closure. We conducted a 7-year retrospective review of speech videofluoroscopy evaluations in patients who had undergone sphincter pharyngoplasty in our center. Between 1989 and 1994, there were 58 patients so treated for postpalatoplasty velopharyngeal dysfunction by two surgeons using the same operative technique. Patients for whom sphincter pharyngoplasty was recommended fulfilled both of the following criteria: (1) velopharyngeal dysfunction caused by an anatomic, myoneural, or combined deficiency of the velopharyngeal sphincter that would not be expected to be managed by speech therapy alone, and (2) preoperative videonasendoscopy and speech videofluoroscopic studies that demonstrated large-gap coronal, circular, or bow-tie closure patterns or velopharyngeal hypodynamism. Of the original 58 patients, 24 underwent postoperative speech videofluoroscopic evaluations with basal views. Of these, 20 of the evaluations (83 percent) were of adequate quality to be included in a research study. Still images showing maximum and minimum excursion of the sphincter in basal view were obtained. To test for observer reliability, the speech videofluoroscopic studies were randomized and presented for measurement to the same individual on two occasions, each session separated by a 1-month time interval. Topographic imaging software was used to obtain maximum and minimum measurements to within 0.1 mm. Partitioning the variance of the data showed that measurement variability was a very small portion of the total, and that difference between the minimum and maximum values was the largest source of variability. Of the total variability in the data, 64.0 percent originated in the minimum/maximum difference, 34.3 percent came from patient variability, and only 1.7 percent resulted from original or repeat measurements. The patient variability may be exaggerated because of variability in the scale of measurement. Results of this study indicate a quantifiable and statistically significant difference in maximum-to-minimum excursion of sphincteric closure. Sphincter pharyngoplasty appears to be dynamic in the majority of cases.

Left ventricular aneurysm repair: an assessment of surgical treatment modalities.

Different closure techniques (linear vs. circular), as well as the efficacy of revascularization in the left ventricular aneurysm repair, with regard to immediate and mid-term results, were assessed and factors having influence on the early mortality and morbidity and survival were analyzed. Between January 1991 and November 1996, 248 patients underwent surgical repair for postischemic left ventricular aneurysm. A total of 26 of them were female (10.50%). Linear closure was employed in 121 patients (48.8 %) and circular (patch endoaneurysmorraphy) closure in 127 (51.2%). Coronary revascularization was added in 203 (81.9%) cases. Patients were followed for an average follow-up time of 39.3 months. Early mortality rate was 6% (15 patients). The difference in mortality rate by the repair method was not statistically significant (8.3% in the linear closure group and 3.9% in the circular closure group, P = 0.15). Absence of preoperative angina pectoris (P = 0.029), dyspnea as the presenting symptom, a preoperative left ventricular segmental wall motion scoring of 14 or greater, a cardiopulmonary bypass duration exceeding 2 h (P = 0.004), an aortic clamping time exceeding 1 h (P = 0.026) were associated with early mortality. Concomitant coronary revascularization had no effect on early mortality. However, low cardiac output state was less frequent in patients with concomitant coronary revascularization (P = 0.022). Functional status improved in both groups. Follow-up extending to 81st month revealed no difference in survival between the groups (84% for linear closure group and 92% in circular closure group, including operative mortality, P = 0.12). However, functional status improvement was better in the patients who underwent circular repair (P = 0.0077). Revascularization appeared as having no important influence on both survival and functional status. A preoperative left ventricular segmental wall motion scoring of 14 or greater was associated with a higher incidence of early mortality, low cardiac output syndrome and poor long-term survival. Left ventricular aneurysm repair is an important therapeutic intervention and can be performed with reliable results, regardless of repair method, either linear or circular. Long term results revealed better functional status in circular repair group. Concomitant coronary revascularization reduced the incidence of low cardiac output state. Performance of the unaffected regions of myocardium was found to be an important determinant of both early and late outcome.

Primary unilateral cleft lip-nose repair: A twenty-five year experience

The study aims at assessing wound healing and safety of single-stage two-layers continuous closure in patients with unilateral cleft lip and palate (UCLP).In this retrospective, descriptive cohort study, we assessed wound healing without fistula formation at 1, 3, and 6 months after a single-stage two-layer UCLP repair, in which the midline suture is continuously circular all along the oral and nasal sides. We examined lengths of hospital stay and the incidence of intra- and postoperative adverse events. Furthermore, we compared the cleft width at birth and on the day of surgery, after presurgical orthopaedics.Eleven UCLP patients underwent one cleft surgery between July 2016 and June 2018 at the age of 8–9 months. Full primary healing occurred in all patients without fistulas. Median length of post-operative hospital stay was 5 days (range = 4–9 days). No intra- or postoperative adverse events above Grade I (according to ClassIntra and Clavien-Dindo, respectively) occurred. Median and interquartile range (IQR) of the palatal cleft width decreased significantly from birth to surgery, i.e., from 12.0 mm (10.8–13.6 mm) to 5.0 mm (4.0–7.5 mm) anteriorly and from 14.0 mm (11.5–15.0 mm) to 7.3 mm (6.0–8.5 mm) posteriorly (p = 0.0033 in both cases).Given these preliminary results, the concept of single-stage continuous circular closure in UCLP has potential for further investigation. However, it remains to be proven that there are no relevant adverse effects such as inhibition of maxillary growth.Registered in clinicaltrials.gov:NCT04108416.

Observation of velopharyngeal closure patterns following isolated stimulation of levator veli palatini and pharyngeal constrictor muscles.

This study, using mongrel dogs, showed the individual movements caused by the levator veli palatini muscle (LVP) and pharyngeal constrictor (PC) contraction, induced by electrical stimulation to each peripheral motor nerve. Each bilateral peripheral motor nerve of the LVP and PC muscles was isolated and stimulated electrically to induce the individual contraction of bilateral LVP and PC muscles. The movements were visualized by use of a fiberscope. Vertical movement of the middle soft palate was observed mainly at LVP contraction. Circular closure in the posterior region of the velopharynx was induced by contraction of the PC muscle. The posterior and lateral wall movements clearly occurred following PC contraction.

Observation of Velopharyngeal Closure Patterns Following Isolated Stimulation of Levator Veli Palatini and Pharyngeal Constrictor Muscles

This study, using mongrel dogs, showed the individual movements caused by the levator veli palatini muscle (LVP) and pharyngeal constrictor (PC) contraction, induced by electrical stimulation to each peripheral motor nerve. Each bilateral peripheral motor nerve of the LVP and PC muscles was isolated and stimulated electrically to induce the individual contraction of bilateral LVP and PC muscles. The movements were visualized by use of a fiberscope. Vertical movement of the middle soft palate was observed mainly at LVP contraction. Circular closure in the posterior region of the velopharynx was induced by contraction of the PC muscle. The posterior and lateral wall movements clearly occurred following PC contraction.

Axial configuration of the velopharyngeal valve and its valving mechanism.

The variability of the normal velopharyngeal (VP) closure mechanism was studied by investigating VP anatomy in relation to its closure mechanism in 60 patients. The axial configuration of the VP isthmus, as observed in axial CT scans at rest, was found to be correlated with VP function in terms of its closure patterns in speech as observed by nasendoscopy. A flat VP isthmus was found to be closed mainly in the anteroposterior direction, forming the coronal closure pattern. A deep VP isthmus is closed by movement of the velum and medial movement of the lateral pharyngeal walls, forming the circular closure pattern. A flat VP isthmus occurs when the hamuli are posteriorly located and the muscular slings, therefore, open more posteriorly. We conclude that posterior insertion of the velar muscles on to the skull base results in a flatter, larger VP axial configuration, whereas an anterior insertion results in a VP axial configuration that is deeper and less flat. A flat VP isthmus contracts mainly in an anteroposterior direction, exhibiting a coronal closure pattern, while a deep or round VP isthmus contracts centripetally, exhibiting a circular closure pattern. Variability of the VP valving mechanism is of anatomic and not of functional origin.

The Ames Astrobleme

The origin of an unusual structural feature near the town of Ames, in the southeastern part of Major County, Oklahoma, has been subject to much speculation. Maps of subsurface horizons show an intriguing circular closure around a low of some 20 mi[sup 2] in area approximately centered at the town of Ames. Early drilling revealed an unusually thick, low Hunton section and an initial characterization was [open quotes]The Hunton Graben.[close quotes] Subsequent deeper drilling discovered Arbuckle dolomite production on a circular rim around this low. Drilling, mapping and core studies now indicate the structure is an impact crater or astrobleme. Initial Arbuckle dolomite wells were located on the rim of the impact crater. While significant oil and gas discoveries have been found, the prolific oil production from wells located on the crater floor established this structure as possibly the largest known productive astrobleme. The first crater-floor well, the D. J. Gregory 1-20 (T21N, R9W), may be the largest oil well established from a single pay in Oklahoma. The pay zone is granite breccia formed as a characteristic central rebound feature in larger astroblemes. Conservatively estimated primary recoveries are over 4 million bbl of oil for this well. Later crater-floor wellsmore » have established production from granite wash overlying brecciated dolomite and from solution-enhanced porosity and fracture systems all sealed by Oil Creek shale.« less

Anterior wall left ventricular aneurysm repair

To determine the efficacy of ventricular closure techniques, we reviewed our experience with 62 patients who survived the repair of aneurysms of the anterior wall of the left ventricular from 1984 through 1989. Forty of these patients underwent aneurysm repair by standard linear closure and 22 by a circular closure technique. After a mean follow-up interval of 3 years, there were no demonstrable differences in angina class, New York Heart Association functional classification, or survival. In 41 surviving patients, postoperative left ventricular dimensions and function were satisfactorily evaluated by standard echocardiographic measurements. No significant differences were found in postoperative long-axis left ventricular systolic diameter or in short-axis systolic or diastolic areas. There was a significantly larger long-axis diastolic diameter in the circular closure group; however, there was no difference in this parameter when the ratios of postoperative to preoperative lengths were compared. Further intragroup comparisons demonstrated an increase in short-axis areas postoperatively within the circular closure group in contrast to a decrease in patients in the linear closure group; these changes were not statistically significant. There was no significant difference in postoperative ejection fraction between the two closure groups, although minor reductions were found in the circular closure group. These data demonstrate no significant difference between the linear and circular closure techniques with respect to standard echocardiographic parameters, functional classification, and survival.

Evaluation of the sphincter pharyngoplasty.

The results of the sphincter pharyngoplasty were evaluated in 139 patients with velopharyngeal incompetence (VPI) who demonstrated active velar elevation. All patients underwent perceptual speech evaluation and lateral phonation radiographic study; select patients underwent multiview videofluoroscopic, flexible nasendoscopic, and pressure-flow studies. All but one patient demonstrated improvement and 109/139 (78.42%) demonstrated resolution of VPI. Sixteen of thirty failed pharyngoplasties were revised. Revision was successful in 8/16 patients yielding an overall success rate of 117/139 (84.17%). Success rate was 67.65 percent for patients managed during the first 5 years and improved to 84.78 percent for patients managed during the last 5 years of this 15-year series. Analysis revealed that younger patients were treated more successfully than older patients, large velopharyngeal areas were treated as successfully as smaller ones, and circular closure patterns were treated more successfully than coronal patterns. The primary cause of failure was insertion of the flap below the point of attempted velopharyngeal contact.

Insect wax secretion the growth of tubular crystals

Filaments of a pure long-chain wax secreted by the wooly alder aphid are shown to represent a previously-uncharacterized, tubular, crystal habit for paraffins. Although this habit is never seen in solution or epitaxial growth of such materials, it requires only a circular closure at the wax secretion site, further growth behavior being controlled totally by van der Waal's intermolecular interactions. The linear paraffin-like wax molecules pack in the filament monolayer envelope with chain axes oriented radially from the filament axis. Elongation of the wax filaments corresponds to the strong interactions along the [110] vectors in the O ⊥ polymethylene chain packing, and stabilization of the filament occurs via strong interchain interactions along [1 10] and [010] in helical paths of opposite chirality.