Tip Protrusion Research Articles

Evaluation of nasal reconstruction procedures results

Before undergoing a reconstructive procedures of the nose most patients ask how they will look postoperatively. Anthropometric measurements of the nose described by Farkas represent standard values. A comparison of pre- and postoperative anthropometric measurements may help to double-check the correctness of intraoperative “eye-balling” measurements with regards to postoperative appearance.Sixty-three patients underwent reconstruction of nasal ala, tip or dorsum. An analysis of standardized pre- and postoperative photographs included measurements of nose width, nose height, nasal tip protrusion, columella width, ala length, intercanthal width, mouth width, philtrum width, upper lip height, lateral upper lip height, cutaneous upper lip height and upper face height. Preoperative measurements were compared to data given by Farkas in young adults. Postoperative changes were evaluated clearly distinguishing between reconstruction of nasal ala, tip and dorsum.All anthropometric indices showed significant differences compared to the Farkas population. There was no significant pre- to postoperative change in any reconstructed region observed, indicating adequate intraoperative measurements.The application of Farkas’ anthropometric measurements described in this study showed reliable and objective results and can help to double-check the previous intraoperative measurements. The correct application of these surgical techniques leads to a satisfying and near to normal postoperative look of the patient.

Nasolabial Soft Tissue Changes After Le Fort I Advancement

To identify the nasolabial soft tissue changes that occur after Le Fort I advancement. A prospective study of patients who had Le Fort I advancement at the Children's Hospital Boston from 2005 to 2007. The pre- and postoperative anthropometeric nasolabial measurements were recorded by a single examiner. A total of 37 patients with a mean age of 18.6 years at the time of operation and a mean follow-up of 12.6 months were recruited. Nearly one half of the study sample (16 of 37) had cleft lip/palate. Direct anthropometry showed a reduction of the nasal length by 1.3 mm while the nasal tip protrusion increased by 1.1 mm. The nasofrontal angle decreased by 9.8° and the upper lip moved forward by 4.15 mm, reflecting the advancement in the maxilla. The height of the cutaneous upper lip increased by 0.4 mm. No significant differences were found in the soft tissue response observed between the cleft and noncleft subjects. Le Fort I advancement produces elevation of the nasal tip, as seen by a reduction in the nasal length, an increase in the nasal tip protrusion, and a concomitant reduction in the nasofrontal angle. Additionally, the cutaneous lip height increased, most likely due to an unfurling of the upper lip.

Residents’ journal review

Residents’ journal review

Anthropometric evaluation of bilateral cleft lip nose with cone beam computed tomography in early childhood: Estimation of nasal tip collapse

Nasal tip features of cleft lip nose cannot be defined well using conventional measurement methods. Therefore, we developed a new method in which vertical nasal tip (the pronasale) position is evaluated based on the Frankfurt-Horizontal plane. This measurement was applied to bilateral cleft lip patients in early childhood. Cone beam computed tomography (CT) records of bilateral cleft lip patients after primary rhinoplasty aged from 5 to 8 years (n=13) were investigated retrospectively. As age-matched controls, data from a normal group (n=17) and complete unilateral cleft lip group after primary rhinoplasty (n=19) were included. In each group, nasolabial angle (β), nasal tip angle (α), nasal width (al-al), columellar length (sn-c' ), nasal tip protrusion (sn-prn), and vertical nasal tip position (sn'-prn'/sn'-n') were investigated. With the exception of vertical nasal tip position and nasal width, the measurement data of the bilateral cleft lip patients were acceptable. In the bilateral cleft lip group, however, vertical nasal tip position was significantly higher and nasal width was significantly larger than those in the normal and unilateral groups (P<0.0001 and P=0.0298; P=0.0001 and P=0.0002, respectively). In cleft lip nose, the lower lateral cartilage that normally composes the nasal tip domes is splayed out, causing cephalic positioning of the pronasale. Nasal tip collapse was more severe in bilateral cleft lip than in the unilateral group. These results were compatible with the fact that many bilateral cleft lip patients require augmentation rhinoplasty after adolescence even after primary rhinoplasty.

The evaluation of the nasal morphologic changes after bimaxillary surgery in skeletal class III maloccusion by using the superimposition of cone-beam computed tomography (CBCT) volumes

BackgroundThe purpose of this study was to evaluate nasal morphologic and maxillary skeletal changes occurring after bimaxillary surgery in skeletal class III patients, using a new method entailing superimposition of cone-beam computed tomography (CBCT) volumes. Materials & methodsThe subjects consisted of 30 adults (15 males and 15 females) who had presented with skeletal class III deformities. The subjects underwent Le Fort I advancement and impaction osteotomy and mandibular setback surgery. For closure of the maxillary vestibular incision, alar cinch suture and V-Y closure were performed. The pre- and post-operative CBCT data were superimposed and evaluated by voxel-by-voxel registration. ResultsAfter surgery, the nasolabial angle, nasal tip angle, nasal tip inclination and columellar angle showed significant increases (P < 0.01). The nasal tip protrusion and nasal height, meanwhile, had significantly decreased (P < 0.01), and the alar base width had increased (P < 0.01). The columellar length and nostril axis angle also had decreased, but the nostril area did not show any significant change. ConclusionsAfter surgery, as the maxilla had been moved upward and forward, the nasal tip was shifted antero-superiorly and the alar base width and nostrils were widened. CBCT superimposition, enabling 3D assessment of nasal morphologic changes, can be an effective tool for simultaneous measurement of skeletal and soft-tissue changes.

Design of an optimum combustion chamber across multiple speed/load points for a heavy-duty diesel engine: analytical design and experimental validation

Analytical tools such as computational fluid dynamics (CFD) and micro-genetic optimization algorithm (GA) have been customized and applied at General Motors Research Laboratories (GMR) for designing a combustion chamber for GM heavy-duty diesel engines, capable of meeting present and future emission targets. In the combined analytical and experimental study described in this paper, the analytical design of the piston bowl shape spanned four key steady-state load points and the performance was validated by testing the analytical design in a single-cylinder engine (SCE). Computations were made to assess the fuel economy performance of the first analytical design. Based on the assessment, a second analytical design was performed with a different set of load points. Computations clearly revealed the progress of performance from the first to the second design. The two optimized piston bowl designs were tested in the SCE in order to validate the predicted progression of performance from the baseline bowl shape and the effect of the choice of the load points for analytical optimization. A multidimensional computer code (KIVA-3V) with a relatively simpler combustion model – the characteristic time-scale combustion (CTC) model – was used along with the GA optimization tool. Experimental results confirmed the predicted emission improvements and performance progression of the analytically designed piston bowls compared with the baseline. Detailed flow field analysis is presented for a selected load point to elucidate the physics behind the sensitivity of observed emission behaviour to variations in injector tip protrusion.

Investigation on the effect of injection system parameters on performance and emission characteristics of a twin cylinder compression ignition direct injection engine fuelled with pongamia biodiesel–diesel blend using response surface methodology

This study is aimed at investigating the effect of injection system parameters such as injection pressure, injection timing and nozzle tip protrusion on the performance and emission characteristics of a twin cylinder water cooled naturally aspirated CIDI engine. Biodiesel, derived from pongamia seeds through transesterification process, blended with diesel was used as fuel in this work. The experiments were designed using a statistical tool known as Design of Experiments (DoE) based on response surface methodology (RSM). The resultant models of the response surface methodology were helpful to predict the response parameters such as Brake Specific Energy Consumption (BSEC), Brake Thermal Efficiency (BTE), Carbon monoxide (CO), Hydrocarbon (HC), smoke opacity and Nitrogen Oxides (NOx) and further to identify the significant interactions between the input factors on the responses. The results depicted that the BSEC, CO, HC and smoke opacity were lesser, and BTE and NOx were higher at 2.5mm nozzle tip protrusion, 225bar of injection pressure and at 30°BTDC of injection timing. Optimization of injection system parameters was performed using the desirability approach of the response surface methodology for better performance and lower NOx emission. An injection pressure of 225bar, injection timing of 21°BTDC and 2.5mm nozzle tip protrusion were found to be optimal values for the pongamia biodiesel blended diesel fuel operation in the test engine of 7.5kW at 1500rpm.

The effect of write current on thermal flying height control sliders with dual heater/insulator elements

The effect of write induced pole tip protrusion on the magnetic spacing of the head/disk interface has to be taken into consideration as flying heights approach the spacing regime of a few nano-meters. Thermal flying height control (TFC) sliders are presently in common use in hard disk drives to control the flying height at the read/write element during drive operations. In this paper the flying characteristics of TFC sliders with dual heater/insulator elements are investigated. Simulation results are shown for situations where the write current is “on” and where the write current is “off”. The effect of design parameters of two heater/insulator elements is studied to optimize the performance of TFC slider.

Experimental study of slider–disk interaction process with thermal-flying-height controlled slider

Thermal flying height (TFC) controlled slider has been introduced in hard disk drive recently. Flying height at the read/write elements of the slider is controlled by thermal pole tip protrusion. Interactions between the TFC slider and disk can be very gentle because the low flying height thermal protrusion area is usually very small. It is still a big challenge to detect very gentle interactions. In this work, a very sensitive method to study very gentle slider–disk interaction in frequency domain has been developed and details of the TFC slider–disk interactions from gentle to strong have been revealed. It is proved that higher heating power is required to initiate the vibration in which higher stiffness part of the slider air-bearing is involved.

Three-dimensional assessment of nose and lip morphology in North Sudanese subjects with Down syndrome

To detail the nasolabial morphologic characteristics of North Sudanese subjects with Down syndrome (DS). Nasolabial morphology was assessed three-dimensionally in 64 North Sudanese subjects with DS aged 4 to 34 years and in 682 sex- and age-matched controls. Three-dimensional facial coordinates were collected using a laser scan, and selected distances, angles, areas, and volumes were computed. Subject and reference data were compared by computing z-scores and Student's t-tests. The nose was significantly smaller (area) in subjects with DS than in reference subjects, and it had a different shape (more flat angle of alar slope, more acute nasal tip angle). The vertical (nasal bridge length, nose height) and anteroposterior (nasal tip protrusion) dimensions were reduced, while the horizontal dimensions (alar base width, inferior widths of the nostrils) were increased. The nasolabial angle was increased. The cutaneous lip volume was significantly smaller, while the vermilion lip area was larger in the subjects with DS. The mouth and philtrum widths were significantly reduced, while the vermilion height was significantly increased. Analyzed subjects with DS had a hypoplastic nose and different upper and lower lips than did reference, normal subjects.

Underdeveloped embryos and germination in Aristolochia galeata seeds

Aristolochiaceae have been described as having seeds with underdeveloped embryos and morphological or morphophysiological dormancy. Aristolochia galeata is a native climber found in the Cerrado biome, associated with road and gallery forest edges. The aims of this study were to investigate: embryo growth rate, morphology and seed germination parameters under different treatments. Embryos were excised to obtain embryo length at four stages: initial, seeds after coat rupture, radicle tip protrusion and cotyledon emergence from the seed coat. Germination tests were conducted at 30 °C under three nitrate concentrations (1, 10 and 20 mM), fluctuating temperature (27/20 °C) and light and dark conditions. We found that seeds have underdeveloped embryos, which take about 301 ± 178 h (±SD) to achieve seed coat rupture, another 205 ± 126 h to reach radicle protrusion and 176 ± 76 h more to the final stage of cotyledon emergence. Germinability was above 52% in all treatments, except in the dark (15%). For all treatments, average germination time was above 290 ± 123 h. Potassium nitrate increased germinability to >87%. No particular treatment was required for embryo development, but seeds in the population that continued to germinate after 1 month were probably in various states of non-deep, simple morphophysiological dormancy. Increased germinability in nitrate treatments and light requirement for germination could prevent germination under unsuitable environmental conditions and be a strategy to increase seedling establishment in the cerrado.

Comparison of Facial Soft Tissue Measurements on Three-Dimensional Images and Models Obtained With Different Methods

The aim of this study was to compare the clinical facial soft tissue measurements with the measurements of facial plaster cast, three-dimensional scanned facial plaster cast, 3-dimensional digital photogrammetrical images, and three-dimensional laser scanner images. Three-dimensional facial images of 15 adults were obtained with stereophotogrammetry and a three-dimensional laser scanner. Facial models of subjects were obtained using silicone impression and were scanned. Landmarks were marked on the subjects and plaster casts, digitized on three-dimensional models, and measured in Mimics 12.0 software (Materialise's Interactive Medical Image Control System, Leuven, Belgium). No statistically significant differences were found between all three-dimensional measurement methods in mouth width, philtrum median height, and nasal width. Comparison of clinical measurements with facial plaster cast measurements revealed that philtral width, nasal tip protrusion, and right lip and nostril heights were wider and longer in clinical measurements than in facial plaster cast measurements. Comparison of clinical measurements to the laser scanned and stereophotogrammetric model measurements revealed that philtrum lateral and lip heights and philtral width were significantly different between methods. When laser scanned and stereophotogrammetric measurements were compared, significant differences were observed in lip and nostril heights. Facial impression may be problematic owing to the depression caused by the impression material especially on the tip of the nose. Laser scanning is not sensitive enough to visualize the deeper indentations such as nostrils. Stereophotogrammetry is promising for three-dimensional facial measurements and even will be better when color identification between mucocutaneous junctions of the lip region is achieved.

Age- and sex-related changes in the normal human external nose

The objective of this study was to measure: (1) normal sex-related dimensions of external nose (linear distances, ratios, angles, volume and surface area); and (2) growth changes between childhood and old age. The three-dimensional coordinates of several soft-tissue landmarks on the external nose were obtained by a non-invasive, computerized digitizer in 519 male and 340 female healthy subjects aged 4–73 years. The subjects were divided into 11 non-overlapping age groups: for children and preadolescent subjects, 2-year spans were used, while larger intervals were used for adolescent and adult subjects. From the landmarks, nasal volume and external surface area; nasal and alar base widths, nasal height, nasal bridge length, philtrum length, nasal tip protrusion, right and left nostril lengths, superior and inferior nostril widths; nasal tip protrusion-to-nasal height, and nasal width-to-nasal height ratios; nasal convexity, alar slope, and nasal tip angles were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. On average, men had larger nasal external volume and area, linear distances and nasal width-to-height ratio than women ( p < 0.01); no sex differences were found for the angles and the nasal tip protrusion-to-nasal height ratio. Age significantly influenced all analyzed measurements ( p < 0.001): nasal volume, area, linear distances increased from childhood to old age, while the nasal tip angle decreased as a function of age. No consistent age related patterns were found for the ratios and the nasal convexity and alar slope angles. Men and women had different age related patterns, with significant sex by age interactions ( p < 0.001). Overall, in most occasions male increments in nasal dimensions were larger than female ones. Data collected in the present investigation could serve as a database for the quantitative description of human nasal morphology during normal growth, development and aging. Forensic applications (evaluations of traumas, craniofacial alterations, teratogenic-induced conditions, facial reconstruction, aging of living and dead persons, personal identification) may also benefit from age and sex based data banks.

110 infants with unrepaired unilateral cleft lip: An anthropometric analysis of the lip and nasal deformities

The aim of this retrospective study was to correlate the width of the cleft lip with the severity of the nasal deformity in unilateral cleft lip and palate (UCLP) patients before primary lip repair. Preoperative impression casts were made. Measurements were taken of the width of the cleft lip (CW), nose (NW), and nasal floor (NFW), alar base height (ABH), columella length (CL), nasal length (NL) and nasal tip protrusion (NTP). The ratio of the non-cleft side (NFW) to the cleft side (NFWR), the ratio of the non-cleft side (ABH) to the cleft side (ABHR), and the ratio of the cleft side (CL) to the non-cleft side (CLR) were calculated. The average NW, NL and CW were higher in the group with complete clefts. There was a negative linear relationship between CW and NFWR, and a positive linear relationship between CW and ABHR in the complete group. In the incomplete group, negative correlations were obtained between CW and NFWR and between CW and ABHR. These findings show that there are correlations between CW and the transverse and vertical imbalance of nose in both groups but not between CW and anteroposterior imbalance of nose.

Optimization of Injection System Parameters and EGR on Jatropha Biodiesel Engine using Taguchi Approach

The diesel engine injection system parameters apart from the operating parameters such as load and speed significantly affect its performance and exhaust emissions. The effect is even adverse sometimes when the engine is tried with some alternative fuels, such as Jatropha biodiesel due to its physico-chemical properties. For better performance and to meet out stringent emission norms, these parameters have to be optimized. An experimental investigation and analysis carried out to simultaneously optimize injection system parameters and exhaust gas recirculation (EGR) levels of small direct injection diesel engine for lower fuel consumption and higher thermal efficiency and peak cylinder pressure is presented in this paper. During the experiments, the different parameters such as fuel type, injection timing, injector opening pressure, nozzle configuration, nozzle tip protrusion, percentage of exhaust gas recirculation (EGR), load torque and speed were changed. Taguchi's signal-to-noise ratio approach was applied to obtain an optimal setting of these parameters. From the experimental results and further analysis it is concluded that under 95% confidence interval the injection timing 340°CA, injector opening pressure 250 bar, nozzle configuration 5x0.18, EGR 0%, load torque 15Nm, speed 1800rpm with Jatropha biodiesel, gave the maximum peak cylinder pressure, while the lowest BSFC with diesel fuel was obtained with nozzle configuration 4x0.18, load torque 15Nm and speed 1800rpm and the highest brake thermal efficiency with nozzle configuration 4x0.18, tip protrusion 2mm, load torque 15Nm and speed 1800rpm. However, the significant control parameters responsible for brake thermal efficiency with their percentage contribution were load torque (79.13%), speed (17.54%), nozzle configuration (1.33%) and tip protrusion (0.96%).

A 3D soft-tissue study of the human external nose region from childhood to old age

The external nose is one of the body structures that continue to modify and enlarge throughout life, well beyond the attainment of skeletal maturity. The objective of the current study was to measure: 1. normal sex-related dimensions of external nose (linear distances, ratios, angles, volume and surface area); and 2. growth changes between childhood and old age. The 3D coordinates of several soft-tissue landmarks on the external nose were obtained by a non-invasive, computerized digitizer in 519 male and 340 female healthy subjects aged 4-73 years. The subjects were divided into 11 non overlapping age groups. From the landmarks, nasal volume and external surface area; nasal and alar base widths, nasal height, nasal bridge length, philtrum length, nasal tip protrusion, right and left nostril lengths, superior and inferior nostril widths; nasal tip protrusion-to-nasal height, and nasal width-to-nasal height ratios; nasal convexity, alar slope, and nasal tip angles were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. On average, men had larger nasal external volume and area, linear distances and nasal width-to-height ratio than women (p < 0.01); no sex differences were found for the angles and the nasal tip protrusion-to-nasal height ratio. Age significantly influenced all analyzed measurements (p < 0.001): nasal volume, area, linear distances increased from childhood to old age, while the nasal tip angle decreased as a function of age. No consistent age-related patterns were found for the ratios and the nasal convexity and alar slope angles. Men and women had different age-related patterns, with significant sex by age interactions (p < 0.001). Overall, in most occasions male increments in nasal dimensions were larger than female ones. Data collected in the present investigation could serve as a data base for the quantitative description of human nasal morphology during normal growth, development and aging. Forensic applications (evaluations of traumas, craniofacial alterations, teratogenic-induced conditions, facial reconstruction, aging of living and dead persons, personal identification) may also benefit from ageand sexbased data banks.

Dynamic Head-Disk Interface Instabilities With Friction for Light Contact (Surfing) Recording

Recent advances in hard-disk drive technology involve the use of a thermal fly-height control (TFC) pole tip protrusion to bring the read/write recording elements of the slider closer to the disk surface and thus achieve terabit per square inch recording densities. A dynamic, contact mechanics-based friction model of the head-disk interface (HDI) that includes roughness and accounts for the TFC geometry and its influence on the HDI dynamics is presented. The model is based on physical parameters and does not include any empirical coefficients. Experimental flyability/touchdown measurements were performed and used to examine in detail the HDI contact criterion in the presence of surface roughness and dynamic microwaviness. Using the model, a procedure is outlined that identifies the optimal clearance and light contact conditions, i.e., the amount of thermal actuation that minimizes, both, the clearance, as well as the flying height modulation. Through calculation of the time varying interfacial forces, mean pressure and shear stress at the HDI can be predicted and used to characterize the contact regime. Based on our results, a light contact regime with reduced bouncing vibrations and low stresses (thus, low wear) that would enable surfing recording is identified.

Long-Term Results in the Bilateral Cleft Lip Repair by Mulliken's Method

To evaluate long-term results in the bilateral cleft lip repair by Mulliken's method, using anthropometric measurements, we assessed the growth of the nose and upper lip after the operation by comparing with those from 30 children without bilateral cleft lip. Forty-four patients had their bilateral cleft lip and nasal deformity repaired simultaneously by Mulliken's method during the period from July 1997 to December 2007. Of these patients, 15 patients had bilateral complete cleft lip, 17 patients had bilateral incomplete cleft lip, and 12 patients had a mixed type of complete and incomplete bilateral cleft lip.To follow up on the growth of the lips and nose after the operation, the following 6 anthropometric measurements were analyzed: nasal tip protrusion, nasal width, columellar length, upper lip height, cutaneous lip height, and vermilion mucosa height. In most patients, nasal length, nasal tip projection, columellar length, and upper lip shape were appropriate. Nasal tip protrusion, nasal width, upper lip height, and vermilion-mucosal height were within normal limit. However, columellar length and cutaneous lip height were relatively shorter than the average values of children without bilateral cleft lip. By performing Mulliken's method, we can achieve natural lip and nasal shape, harmonious Cupid's bow, appropriate nasal projection, and natural philtrum.

Anthropometric evaluation of complete unilateral cleft lip nose with cone beam CT in early childhood

Anthropometric evaluation of cleft lip nasal growth has generally been done based on Mulliken's method. However, this method does not allow sufficient evaluation of nasal tip position. Nasal tip position is the most important parameter for evaluation of nasal growth. Therefore, an anthropometric study was performed including vertical nasal tip position. Fifteen normal subjects in early childhood (Normal Group), 15 age-matched subjects with complete unilateral cleft lip and alveolus or complete unilateral cleft lip, alveolus, and palate without rhinoplasty (No Rhinoplasty Group), and 16 age-matched subjects with complete unilateral cleft lip and alveolus or complete unilateral cleft lip, alveolus, and palate with synchronous rhinoplasty during primary repair of cleft lip (Primary Rhinoplasty Group) were compared. Nasolabial angle (beta), nasal tip angle (alpha), nasal width (al-al), columellar length (sn-c'), nasal tip protrusion (sn-prn), and vertical nasal tip position (sn'-prn'/sn'-n') were measured. With the exception of vertical nasal tip position, the measurement data of the Primary Rhinoplasty Group were excellent. In the cleft lip groups, vertical nasal tip position was significantly higher than that in the Normal Group. Our results showed that the nasal tips of cleft lip patients showed significant congenital upward deviation in comparison with normal children. In Mulliken's method, this upward deviation cannot be evaluated properly. After synchronous rhinoplasty, measurement results showed improvement in our patients without significant deterioration of tip position. These findings represent evidence in support of synchronous rhinoplasty.

Rectangle Tongue Template for Reconstruction of the Hemiglossectomy Defect

To determine if a rectangular template free tissue transfer is effective for the reconstruction of the hemiglossectomy defect. Prospective case series. Tertiary care academic medical center. A total of 13 patients (male to female ratio, 8:5; mean age, 55 years) presenting with squamous cell carcinoma of the oral tongue from May 2000 to December 2002. Of the 13 patients, 7 received postoperative radiotherapy and 2 received prior radiotherapy. The radial forearm was the donor site in 11 patients and the lateral arm and anterolateral thigh in 1 patient each. The mean flap area was 50 cm(2) (range, 24-80 cm(2)). Major and minor complications, speech and swallowing assessment, oral cavity obliteration, premaxillary contact, tongue elevation, and tongue protrusion. There were no major complications, and 2 of the 13 patients experienced minor complications. Of the 13 patients, 12 achieved the goals of oral cavity obliteration and premaxillary contact and resumed solid oral intake. One patient remained G-tube dependent owing to toxic effects from previous chemoradiation treatment. The mean tongue tip protrusion was 0.7 cm (range, 0-1.7 cm), and the mean elevation was 1.7 cm (range, 1-3 cm). Patients with protrusion greater than 0.8 cm had better swallowing scores for "range of solids" (5.8 of 6 vs 3.9 of 6; P = .045) and "eating in public" (4.6 of 5 vs 3.5 of 5; P = .10). The average patient resumed a full range of liquid and solid intake with minimal restrictions and believed that their speech was mostly understandable with occasional repetition. The template-based rectangle tongue flap effectively restored speech and swallowing function in this group of patients. Tongue protrusion greater than 0.8 cm is associated with better swallowing results.