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Biomedical subjects

W Hochban

Publications and source records attributed to W Hochban.

34 records · Page 2Linked to original sources
PubMed1994

[Does velopharyngoplasty as a speech-improving measure in cleft palates lead to obstructive sleep apnea?].

Velopharyngoplasty performed to correct velopharyngeal insufficiency in cleft palate patients may cause obstructive sleep apnea in individual cases. The aim of this study was to answer the question, following velopharyngoplasty to what extent and with what frequency can signs of breathing disturbances during sleep be observed. Following the recommendations of the German Sleep Society, a step-by-step procedure was adopted. In 25 patients, in some cases before the operation and in all cases following surgery, nightly oxygen saturation, heart rate, and snoring were recorded. When observable pathological signs surfaced, a cardiorespiratory polygraph was taken. Up to this point only quickly passing signs of sleep related breathing disturbances have been observed. In not a single case could lasting sleep related breathing disturbances as a result of velopharyngoplasty be proven. Nevertheless, the call for pulse oximetric monitoring in the immediate postoperative phase together with corresponding pre-operative observation is legitimate. Even if at this point the danger of sleep related breathing disturbances following velopharyngoplasty appears to be minimal, these preliminary results should be polysomnographically studied within the framework of a much larger test study in order to reach still more reliable conclusions and in order to intercede if necessary with counter measures in the rare individual case of breathing disturbance during sleep following velopharyngoplasty.

Adolescent↗
PubMed1994

Acoustic rhinometry: a new diagnostic procedure--experimental and clinical experience.

The diagnostic value of transnasal acoustic reflection measurements (Rhinoklack) was investigated in an experimental and clinical study. Within the range of nasal and epipharyngeal dimensions, in vitro and in vivo measurements showed satisfactory reproducibility. A simple maneuver helps to identify the transition from the rigid nasal cavity to the movable epipharynx. The location and the amount of nasal obstruction can be verified and traced back to their morphologic correlative. The effect of decongestion on nasal volume was measured for normal mucosa (41% enlargement) and mucosa altered by scar formation after septoplasty and turbinoplasty (21% enlargement). After maxillomandibulary advancement of 10 mm for obstructive sleep apnea, the EV index representing epipharyngeal volume (EV) showed an average increase of 6 cm3.

Acoustics↗
PubMed1994

Resorbable dowels for osteosynthesis of noncongruent bone fragments.

Dowels, in contrast to screws, offer the great advantage in osteosynthesis that no pressure peaks occur by functional loading rectangular to the screw axis; consequently, there is no bone resorption and no loosening of the fixation because of the even contact of dowel and bony surface. However, dowels must be made of resorbable materials because they cannot be removed. We developed double-spreading dowels with a slotted tube whose outside is cylindric and the inside conical at both ends. Two conical screws in the core of the dowel moved toward each other cause symmetric expansion of the outer surface. Dowel material consisted of polylactic acid with an inherent viscosity > 7 dl/g (Resomer 214, Böhringer Ingelheim). A model simulating retromolar sagittal split osteotomy was chosen for experimental research because, in this case, noncongruent bone segments have to be osteosynthesized to regenerate in the sense of distance osteogenesis. Two segments of synthetic material were synthesized like proximal and distal segments after retromolar sagittal split osteotomy fixed by two or three dowels without coherent contact. The synthesized segments underwent a continuous jiggling stress test comparable with the physiologic stress of a jaw for about 4 weeks. Dowel fixation proved to be nearly as stable as position-screw fixation. Resorbable dowel fixation yields experimentally the required stability for the time needed for bony regeneration.

Analysis of Variance↗
PubMed1994

Morphology of the viscerocranium in obstructive sleep apnoea syndrome--cephalometric evaluation of 400 patients.

The aim of this study was the cephalometric evaluation of patients with obstructive sleep apnoea in order to see whether certain craniofacial characteristics exist. Additional to known skeletal facial parameters cephalometric analysis has been used to establish pharyngeal dimensions. Surprisingly, many patients with obstructive sleep apnoea (nearly 40%) showed certain craniofacial characteristics which apparently predispose to pharyngeal obstruction and to obstructive sleep apnoea. More than one third of 400 patients prove to have pharyngeal narrowing combined with more or less distinct maxillary and mandibular deficiency. Cephalometric evaluation helps to identify sleep apnoea patients, in whom maxillomandibular advancement surgery might be effective in the treatment of obstructive sleep apnoea. According to our results, an indication for surgical treatment by maxillomandibular advancement exists in patients with maxillary and especially mandibular deficiency combined with pharyngeal narrowing.

Adult↗
PubMed1994

Acoustic rhinometry: rationale and perspectives.

Acoustic rhinopharyngometry provides a new, non-invasive access to upper airways geometry. In this experimental and clinical study the diagnostic value of acoustic rhinopharyngometry was investigated. In vitro measurements showed adequate accuracy, reliability and spatial resolution within the range of nasal and epipharyngeal dimensions. Clinical measurements confirmed reasonable reproducibility for the evaluation of nasal (NV) and epipharyngeal (EV) volume. Decongestion with xylometazoline resulted in a 36% enlargement of nasal volume on average. The alteration of pharyngeal soft tissues due to maxillomandibulary advancement of 10 mm correlated to an increase of the EV-index of 6 cm3. Acoustic rhinometry identifies location and amount of nasal obstruction and in addition allows differentiation between obstruction due to mucosal hypertrophy and that due to skeletochondral deformity. Changes in the epipharyngeal volume following maxillary and mandibular osteotomies can be estimated in comparison with the preoperative situation.

Acoustics↗
PubMed1994

Surgical treatment of obstructive sleep apnea by maxillomandibular advancement.

In recent years obstructive sleep apnea syndrome has gained increasing interest. Treatment of choice is nasal continuous positive airway pressure ventilation during sleep for upper airway patency, which does not cure sleep apnea and has to be applied throughout a patient's lifetime. In respect to various underlying pathomechanisms, in certain cases with craniofacial disorders, causal therapy by craniofacial osteotomies seems possible. A series of 21 consecutive patients with maxillary and mandibular deficiency were treated primarily with a 10-mm maxillomandibular advancement by retromolar sagittal split osteotomy and Le Fort-I osteotomy, respectively. Obstructive sleep apnea syndrome was considerably improved in all patients. In 20 of 21 patients, the postoperative respiratory disturbance index (RDI) was reduced clearly to under 10, oxygen saturation rose and sleep quality improved. This was achieved by a maxillomandibular advancement of 10 mm without secondary refinements. In one patient the RDI could only be reduced to 20, probably due to insufficient maxillary advancement; oxygen desaturations still existed despite secondary corrections. These results indicate that successful surgical treatment is possible in a high percentage of selected patients with certain craniofacial characteristics. In addition to cardiorespiratory polysomnography there should be routine cephalometric evaluation of all patients. Maxillomandibular advancement should be offered as an alternative therapy to all patients with maxillary and/or mandibular deficiency or dolichofacial type in combination with narrow posterior airway space.

Adult↗
PubMed1993

Prognosis of third molar eruption.

This study was designed to find a threshold value for an increased probability of upper and lower third molar eruption measured on rotational tomograms compared with lateral cephalometric radiographs. Twenty-seven patients had been followed over a 7-year period. Space available in the retromolar region had been measured at mean ages of 13, 16, and 20 years. At early ages, patients with erupted third molars had significantly more space available in the retromolar region. More wisdom teeth had erupted with a space/width ratio > or = 1 measured on rational tomograms and a distance of 25 mm or more on lateral cephalometric radiographs. There was a strong correlation between rotational tomograms and lateral cephalometric radiograph measurements as well as good reliability and reproducibility compared with study casts.

Adolescent↗
PubMed1993

Long-term results after maxillary advancement in patients with clefts.

In order to evaluate relapse tendencies after maxillary advancement, 31 patients were examined preoperatively, postoperatively, and 1 year postoperatively; 14 of whom had clefts of the lip, alveolus, and palate. Patients with maxillary deficiency were selected in a method that mere sagittal displacement was planned. Any patients with major vertical or transverse changes or additional mandibular surgery were excluded. Treatment consisted of maxillary advancement by Le Fort I osteotomy and miniplate fixation. Besides clinical examination, skeletal and dental changes were assessed cephalometrically. Results revealed a certain relapse tendency of the displacement in the noncleft group that compared favorably to the cleft group. This relapse is dependent on the amount of advancement. Despite minor differences, the two groups did not differ significantly based on maxillary advancement, so besides advancement surgery there must be another factor, cleft, to explain the different relapse tendencies between patients with and without clefts.

Adolescent↗
PubMed1993

[Obstructive sleep apnea syndrome caused by craniofacial abnormalities].

Patients with obstructive sleep apnoea syndrome frequently present distinct changes in the craniofacial skeleton that result in a structural narrowing of the pharynx and promote pharyngeal collapse during sleep. The evaluation of the clinical data of patients with and without craniofacial dysmorphia reveals that mean age, mean Broca index and the number of additional diseases is decreased in patients with craniofacial dysmorphia. Young patients or patients with normal weight and OSAS usually present such skeletal changes. The number of sleep-related breathing disorders and the extent of nocturnal desaturation are also decreased in the group of patients with dysmorphia. The structure of sleep is similarly disturbed in both groups. In most cases patients with severe obstructive sleep apnoea have normal cephalometric data.

Adult↗
PubMed1993

[Functional anatomy of the upper airway: cephalometric and reflective acoustic studies].

Cephalometric analysis is an effective tool for the evaluation of craniofacial and pharyngeal changes in obstructive sleep apnoea. Meanwhile even for pharyngeal changes a lot of average values exist, which show significant differences for many cephalometric parameters. Approximately 40% of patients with obstructive sleep apnoea proved to have a retrognathic, dolichofacial appearance, which seems to contribute to obstructive apnoeas by retropositioning of the skeletal fixation for the muscles of the floor of the mouth and the tongue. Acoustic rhinometry for transnasal cross-sectional measurements of the upper airways is still under clinical trial. Whether it is a valuable supplement to cephalometric evaluation in the future will be mainly a question of software development.

Airway Resistance↗
PubMed1993

[Surgical treatment of obstructive sleep apnea by modifying the facial skeleton with reference to cephalometric parameters].

UNLABELLED: Cephalometry: Morphologic alterations can be found in a great deal of patients with OSAS, predisposing to the rise of sleep apnea. In addition to preexisting investigations we developed a cephalometric analysis to judge these alterations in patients with OSAS. Comparing 160 patients to healthy people pharyngeal obstructions could be found in more than one third of the patients, usually combined with a retrognathic dolichofacial morphology. SURGICAL PROCEDURE: As successful treatment of our own patients shows, curing of obstructive sleep apnea is possible in respect of these cephalometric alterations. The basis of surgical treatment consists of surgical advancement of the mandible by sagittal split osteotomy and advancement of the maxilla by Le Fort I-osteotomy. Advancement surgery must be done in consideration of the morphologic alterations mentioned above. Additionally secondary procedures can be taken into account as genioplasty, soft-tissue-corrections or corrections of the upper airways.

Cephalometry↗
PubMed1990

The one-stage repair of bilateral cleft lip.

Twenty children with broad, complete clefts of lip, alveolus, and palate were studied. For functional restoration of the lip in complete bilateral clefts we advocate a one-stage modification of the Millard procedure even if the clefts are broad. Orthodontic treatment is done first to achieve maximal maxillary growth. Reconstruction of the lip is done at the age of 5 to 6 months. Our method of lip restoration is described with special attention to the muscle reconstruction. The lengthening of the columella, which is done at the age of 4 years, is still a problem.

Cleft Lip↗
PubMed1989

Presurgical orthopaedic treatment using hard plates.

Our concept in the treatment of unilateral clefts of lip, alveolus and palate includes early maxillary orthopaedic treatment starting immediately after birth until the end of the first year of life and the surgical closure of the lip at three months and of the soft palate at twelve months. Hard palate and alveolus are closed after three years by secondary osteoplasty in the alveolar region. The appliance is made of hard acrylic resin and is adjusted monthly to allow for growth. It thus encourages passive orthopaedic guidance of maxillary growth. The local compatibility of the plate was excellent and the acceptance by the children created no problems until tooth eruption. Follow-up studies were conducted on twenty children treated in this way until three years of age. After the first year results show a good and harmonious arch alignment without any collapse of the alveolar segments. The cleft narrows and the steepness of the palatal slope flattens. This maxillary development is arrested after suspension of orthopaedic treatment, and a slight collapse of the alveolar segments is observed.

Acrylic Resins↗