Tunneled island pedicle flap reconstruction for upper lateral cutaneous lip defects.

BACKGROUND: Esthetic upper lateral cutaneous lip reconstruction preserves the apical triangle, nasolabial fold symmetry, and free margin position. The tunneled island pedicle flap (IPF) is a novel single-stage reconstruction to achieve these goals. OBJECTIVES: Describe the technique and patient and surgeon-reported outcomes for the tunneled IPF reconstruction of upper lateral cutaneous lip defects. METHODS: Retrospective chart review of consecutive tunneled IPF reconstruction following Mohs micrographic surgery (MMS) at a tertiary care center between 2014 and 2020. Patients rated their scars using the validated Patient Scar Assessment Scale (PSAS), and independent surgeons rated scars using the validated Observer Scar Assessment Scale (OSAS). Descriptive statistics were generated for patient demographics and tumor defect characteristics. RESULTS: Twenty upper lateral cutaneous lip defects were repaired with the tunneled IPF. Surgeons rated scars with a composite OSAS score of 11.83 ± 4.29 (mean, SD) [scale of 5 (normal skin) to 50 (worst scar imaginable)] and an overall scar score of 2.81 ± 1.11 [scale of 1 (normal skin) to 10 (worst scar imaginable)]. Patients rated their scars with a composite PSAS score of 10 ± 5.39 [scale of 6 (best possible score) to 60 (worst)] and with an overall score of 2.2 ± 1.78 [scale of 1 (normal skin) and 10 (very different from normal skin)]. One flap was surgically revised for pincushioning, but none experienced necrosis, hematoma, or infection. CONCLUSIONS: The tunneled IPF is a single-stage reconstruction for upper lateral cutaneous lip defects with favorable scar ratings by patients and observers.

Heart rate variability in infants, children and young adults.

Heart rate variability was studied in normal subjects age 1 month-24 years while awake and in active and quiet sleep using 24 h continuous recordings of the ECG. Variability was quantified by spectral analysis for the two frequency bands: low frequency (LF) 0.03-0.15 Hz, high frequency (HF) 0.15-0.6 Hz. Heart rate variability showed an age dependence, being in general an increase in LF, HF and total power from 0-6 years, followed by a decrease to 24 years. The infant group showed some exceptions to this trend. Developmental changes of parasympathetic and sympathetic mediation of heart rate are postulated as important determinants of age dependence of heart rate variability.

Correlation algorithm and sampling techniques for estimating the signal-to-noise ratio of the electrocardiogram.

An algorithm, based on correlation techniques, is proposed for estimating the signal-to-noise ratio of very low frequency signals contaminated by white and flicker noise. Sampling techniques based on converting a single continuous signal into two time series that satisfy the requirements of cross-correlation functions are proposed. The algorithm has been tested on simulated data and the electrocardiogram transduced from ten patients.

Locomotor-respiratory coupling during wheelchair propulsion.

Visceral movement due to impact loading is believed to play a role in the locomotor-respiratory coupling (LRC) that has been detected in a number of mammalian species. In the bird and bat species in which LRC has been described, the effect of the wing muscles on the timing of respiration appears to be a dominant influence. To test the hypothesis that LRC occurs in humans propelling wheelchairs (where there is no impact loading and the arms are used for locomotion), we studied 10 wheelchair athletes on a motorized treadmill at three speeds. Each subject's data were analyzed by spectral analysis (based on the fast Fourier transform), which detected apparent LRC (rates within 1% of a single-digit integer ratio) in 12 (40%) of the 30 test settings. However, a control analysis, in which each subject's arm-thrust rates were compared with another subject's breathing rates, revealed apparent (but false) coupling in 8 (27%), not significantly less often (using the chi 2 test). These findings appear to refute the hypothesis that LRC occurs during wheelchair propulsion. These data are consistent with the theory that the visceral piston is important to LRC and suggest that rhythmic arm movements are insufficient to induce the phenomenon in this setting.

Landmarking of cephalograms using a microcomputer system.

Landmarks, or certain characteristic reference points, on cephalograms are used as a diagnostic aid employed in treatment planning by orthodontists. This work presents an algorithm for recognizing some anatomical features and locating landmarks on lateral skull X rays (cephalograms) using digital image processing and feature recognition techniques. A cephalogram is digitized and stored in a computer memory. Prefiltering is applied to remove image noise. The bony and flesh profiles of jaw and front face are traced. Using these profiles the algorithm locates 17 points on the image, some on bony features and others on soft tissue. To locate these points, edge-enhancement, thresholding, and edge-detection techniques are applied. The algorithm can be run on an IBM compatible microcomputer.

An adaptive "Wiener" filter for estimating the time-derivative of the left ventricular pressure signal.

This communication presents the development of an optimal digital differentiating filter based on the Wiener theory for estimating the peak derivative of the left ventricular pressure (LVP) signal. The magnitude coherence function is used to estimate the signal and noise spectra. The peak derivative obtained by this method is found to be within 2% of the results obtained by a seven-point second-order data fit and a DFT technique.

Automatic landmarking of cephalograms.

This paper presents an algorithm for automatically locating certain characteristic anatomical points called landmarks on cephalograms (skull X-rays). These landmarks are used by orthodontists in diagnosis and treatment planning. The algorithm uses digital image processing and feature recognition techniques to locate the landmarks. A resolution pyramid of the digitized cephalogram is first created. The algorithm works on the smaller, lower resolution images to locate features of interest and moves to the bigger, higher resolution images if greater location accuracy is required. Prefiltering using the median filter, contrast enhancement using histogram equalization, and edge enhancement using different gradient operators are performed on the images. The algorithm uses anatomical knowledge of the human facial structure to search for features containing the landmarks. The accuracy of the algorithm in locating the landmarks is compared with values obtained from human experts. At present the algorithm attempts to locate 10 landmarks of 27 needed for a complete analysis. All 10 landmarks have been successfully located on five cephalograms of varying quality.

Two-dimensional Fourier spectrum of QRST integral maps in classification of patients prone to ventricular arrhythmia.

Two-dimensional Fourier spectra of QRST integral maps, obtained by body surface potential mapping, were analyzed to identify subjects prone to ventricular arrhythmia, when they have not been identified by the extrema count method. The diagnostic performance (84.38 percent) of the peak value of the Fourier spectrum as a classifier for subjects prone to ventricular arrhythmia showed an improvement of 3.65 percent over the use of the extrema count method as a classifier.

Sinus arrhythmia in children with atrial septal defect: an analysis of heart rate variability before and after surgical repair.

The expression of sinus arrhythmia depends on separation of the systemic and pulmonary venous return to the heart as well as on normal autonomic control mechanisms. Patients with atrial septal defect provide a naturally occurring experiment of communication between the two venous systems. In adults with atrial septal defect sinus arrhythmia is minimal or absent. But children with atrial septal defect retain appreciable sinus arrhythmia, although this is not recognised in published reports. To understand why this is so, continuous electrocardiograms were recorded before and after operation in 10 children (aged 4-16 years, mean 6.3) with atrial septal defects and in 10 normal children (aged 5-7 years, mean 6.1). Mean RR intervals were calculated for periods of one minute, and the standard deviation was used as an index of heart rate variability (that is sinus arrhythmia). Frequency analysis (spectral analysis) was also performed on a continuous beat to beat record of heart rate to describe the frequency components that may reflect autonomic activity. The results confirmed the presence of considerable sinus arrhythmia in children with unoperated atrial septal defect. None the less, the standard deviation of RR intervals in the children with unoperated atrial septal defect was significantly less than that for the normal children, and variation increased after closure of the defect. Power spectral analysis of instantaneous heart rate indicated that the high frequency (0.15-0.45 Hz) vagally mediated component of variability was lower for patients than for controls which may indicate abnormalities of autonomic control of heart rate in these children. The comparative retention of sinus arrhythmia in children with atrial septal defect may relate to the small size of the right atrium or differences in myocardial compliance compared with adults.

Coupling of cardiac and locomotor rhythms.

The pressure within exercising skeletal muscle rises and falls rhythmically during normal human locomotion, the peak pressure reaching levels that intermittently impede blood flow to the exercising muscle. Speculating that a reciprocal relationship between the timing of peak intramuscular and pulsatile arterial pressures should optimize blood flow through muscle and minimize cardiac load, we tested the hypothesis that heart rate becomes entrained with walking and running cadence at some locomotion speeds, by means of electrocardiography and an accelerometer to provide signals reflecting heart rate and cadence, respectively. In 18 of 25 subjects, 1:1 coupling of heart and step rates was present at one or more speeds on a motorized treadmill, generally at moderate to high exercise intensities. To determine how exercise specific this phenomenon is, and to refute the competing hypothesis that coupling is due to vertical accelerations of the heart during locomotion, we had 12 other subjects cycle on an electronically braked bicycle ergometer. Coupling was found between heart rate and pedaling frequency in 10 of them. Cardiac-locomotor coupling appears to be a normal physiological phenomenon, and its identification provides a fresh perspective from which to study endurance.

Heart-rate variability in children. Spectral analysis of developmental changes between 5 and 24 years.

The variation in instantaneous heart rate is most prominent in infants and younger subjects. In a preliminary study of the effects of maturation on heart rate, we compared the heart rate variations of 29 children and young adults in three groups between 5 and 24 years of age. We used spectral analysis to determine the intensity of the variations in each of the two main frequency bands in which variations occur: HF, 0.15-0.45 Hz, and LF, 0.03-0.15 Hz. Three-minute segments of continuous instantaneous heart rate were recorded for each subject in standing and supine positions. The group mean LF and HF amplitudes and the L/H ratio decreased between 5 and 10 years of age in both positions, significantly for LF and L/H in the supine position (p less than 0.05). Half of the youngest group of children had adult LF amplitude values by 5 years of age; the others had much higher levels, indicating increased low frequency variation at this age. Thus the high variation in heart rate in very young subjects is most prominent in the LF range. These preliminary results, considered with previous pharmacological studies, suggest that many children have a significant decrease in sympathetic activity between 5 and 10 years of age and possibly a slight decrease in parasympathetic activity. Spectral analysis of heart rate appears a promising technique for investigating the development of neural control of the heart.

Spectral analysis of the EMG and diaphragmatic muscle fatigue during periodic breathing in infants.

Periodic breathing occurs commonly in full-term and preterm infants. The mechanisms which switch breathing on and off within a cycle of periodic breathing are not certain. Since immature infants may experience diaphragmatic muscle fatigue, one potential switching mechanism is fatigue. Power spectra of the electromyogram, uncontaminated by the electrocardiograph artifact, were studied for evidence of diaphragmatic muscle fatigue during spontaneous periodic breathing in infants. A fall in the high-frequency (103-600 Hz) power and an increase in the low-frequency (23-47 Hz) power during periodic as compared with normal breathing would indicate fatigue. This effect was not observed in any of the infants studied. Hence, there is no evidence that periodic breathing is the result of diaphragmatic muscle fatigue. This finding suggests that the effect of drugs such as theophylline in eliminating periodic breathing may be unrelated to the fact that they also reduce fatigue.

Periodicities in respiration and heart rate in newborns.

Periodic breathing is common in normal infants, but may be associated with prolonged apnea leading to crib death. The mechanisms of periodic breathing and its relation to normal breathing patterns are unclear. We recorded respiratory and heart rate (HR) patterns of 11 healthy newborn infants during quiet sleep, in both normal and periodic breathing. Spectral analysis of the respiratory pattern revealed a low-frequency (LF) periodicity in normal breathing approximately equal to the frequency of periodic breathing when this occurs. Periodic breathing thus appears to be an exaggeration of an underlying slow amplitude variation which is present in regular breathing. LF periodicity also appeared in the HR pattern in both normal and periodic breathing, suggesting an LF modulation of cardiovascular control as well. The lack of a definite phase relation between HR and ventilation at LF may indicate dominant peripheral, rather than central, interactions between HR and respiration at these frequencies.