Evaluation of airflow characteristics before and after septoplasty in unilateral cleft patients with a deviated nasal septum: a computational fluid dynamics study.

The aim of this study was to evaluate changes in airflow characteristics before and after septoplasty in unilateral cleft lip and palate (UCLP) patients using computational fluid dynamics (CFD) models. The study was designed as a prospective cohort study involving pre- and postoperative computed tomography data from 12 UCLP patients with a deviated nasal septum who underwent septoplasty. CFD analysis of nasal airflow was conducted to study changes in velocity, pressure, volume, nasal resistance, and wall shear stress of the nasal domain before and after surgery. The study results demonstrated a statistically significant difference in pressure drop after septoplasty: median 116.10Pa (interquartile range (IQR) 749.02Pa) preoperative compared with 43.39Pa (IQR 349.01Pa) postoperative (P= 0.004). Maximum wall shear stress was found to be approximately three times lower after septoplasty: median 6.15 Pa (IQR 1908.62 Pa) preoperative versus median 2.51 Pa (IQR 540.06 Pa) postoperative (P=0.002). Changes in nasal resistance were also found to be statistically significant: median 460.59 Pa·s/l (IQR 1946.99 Pa·s/l) preoperative versus median 166.61 Pa·s/l (IQR 694.08 Pa·s/l) postoperative (P=0.04). These values demonstrate significant changes in flow dynamics after surgery indicative of a more uniform airflow pattern and stabilization of the nasal mucosa.

Minimally-invasive anterior maxillary distraction technique in patients with cleft lip and palate and maxillary deficiency: an evaluation of 106 patients.

Our aim was to evaluate the feasibility of a minimally-invasive surgical technique for anterior maxillary distraction osteogenesis to correct maxillary hypoplasia in patients with clefts. A modified Y distractor was placed intraorally in 106 patients with cleft- associated maxillary deficiency to facilitate protraction of the maxilla. Subsequently the patients had an anterior maxillary osteotomy through a minimally invasive incision, followed by activation of the appliance at the rate of 0.8mm/day until positive overjet was achieved. The patient's lateral cephalograms were evaluated preoperatively (T1), after activation (T2), and one year postoperatively (T3). Collected data were assessed with the paired t test, and probabilities of < 0.001 were accepted as significant. A mean (SD) of 10.4 (2.58) mm anterior maxillary advancement was obtained in all patients after 10-13 days of distraction. The sella-nasion-point A (SNA) angle increased from 75.37° to 83.01°. When we compared the cephalometric variables at T1 and T2, the mean maxillary length and overjet at T2 were significantly higher (p<0.001). The comparison of mean values at T2 and T3 was not significant. Minimally invasive anterior maxillary distraction with the modified Y distractor resulted in changes after activation that were consistent one year postoperatively, making it a conservative, less traumatic, and effective treatment of cleft-related maxillary deficiency.

Long-term effect of presurgical nasoalveolar molding on growth of maxillary arch in unilateral cleft lip and palate: randomized controlled trial.

The objective of this study was to investigate the long-term effect of presurgical nasoalveolar molding (PNAM) on growth of the maxillary arch through early childhood until 6 years of age in complete unilateral cleft lip and palate (UCLP) patients presenting for PNAM at different ages. Complete UCLP patients who were treated at our centre were divided into two groups. The study group underwent PNAM and was further subdivided into three subgroups (PNAM initiated within 1 month, between 1 and 6 months, and between 6 and 12 months of age in subgroup I, II, and III, respectively). The control group did not undergo PNAM and was further subdivided into three subgroups. Patients were evaluated at T1 (first visit), T2 (before cheiloplasty), and T3 (at 6 years). Between T1and T2, the intersegment distance (ISD) reduced significantly in the study group but increased in the control group, whereas the intercanine width (ICW) in both the study and control groups did not show significant change. Between T2 and T3, ISD and ICW were reduced significantly in the control group due to arch collapse, whereas in the study group, ISD reduced slightly with ICW remaining almost similar to noncleft norms. We conclude that reduced ISD following PNAM improves arch symmetry and stability, and thus may prevent arch collapse in the long term.

Histologic evidence of osseointegration in the irradiated and reconstructed mandible: a case report.

Osseointegrated implants are widely used in dental rehabilitation. They are particularly valuable if the structures supporting a denture had to be removed because of oral cancer. Additionally, many of these patients undergo radiotherapy, but cancer and radiotherapy are seen as relative contraindications for implant therapy. In the literature, there are few clinical studies documenting successful oral rehabilitation using implants in such patients. The authors report a clinical case in which histologic evidence of osseointegration can be demonstrated in an irradiated and reconstructed mandible. This observation should encourage the extended application of implants in rehabilitation following oral cancer surgery.

A new method of inserting endosseous implants in totally atrophic maxillae.

A new method is described (Sailer, 1988) whereby endosseous implants are inserted in the totally atrophic maxilla, the intermaxillary relationship and vertical dimension corrected and a vestibuloplasty performed during one surgical procedure. The method can also be used to treat minor degrees of maxillary alveolar atrophy. The procedure enables 20 mm-long Titanium screws to be used in totally atrophic maxillae. The following surgical procedures are carried out during one operation: A Le Fort I osteotomy, removal of the mucous membrane of the sinus floor, obturation of the denuded maxillary sinus floor by autologous bone grafts from the iliac crest, simultaneous insertion of Titanium screws, fixation of the down-fractured maxilla by miniplates, and a modified submucous vestibuloplasty. Intermaxillary relationship and vertical dimension can be normalized, and the aesthetic results are excellent. To date 35 implants of which none has been lost, have been placed in 5 patients.

A prospective study on changes in the sensibility of the oral mucosa and the mucosa of the upper lip after Le Fort I osteotomy.

A prospective study on 21 patients was performed in order to investigate the changes in the sensibility of the oral mucosa and the mucosa of the upper lip after a Le Fort I osteotomy. Patients were followed-up 1 month, 3 months and 6 months postoperatively. The sensibility of the mucosa was tested using electrical sensimetry (Laitinen, 1987). The teeth were tested with carbon dioxide snow (Obwegeser and Steinhäuser, 1963). A picture of the marked hypoaesthetic area was performed and magnified 1:1 if a hypoaesthesia of the cutaneous distribution of the infraorbital nerve was found. The area was measured using a Macintosh II CX computer. It was demonstrated, that after 3 months the infraorbital nerve regained its function completely. The greater palatine nerve and the posterior superior alveolar nerve demonstrated an incomplete recovery of sensory function after 6 months. After 6 months 92.8% of the teeth reacted to carbon dioxide snow. Within the first 6 months postoperatively, no pulpe necrosis was observed. No correlation could be found between the amount of anterior maxillary movement and the degree of hypoaesthesia of the infraorbital nerve. Dentate Le Fort I osteotomies showed a better sensory regeneration of the greater palatine nerve than edentulous Le Fort I osteotomies. After Le Fort I osteotomies in 2 parts, more hypoaesthesia of the greater palatine nerve was observed than after Le Fort I osteotomies in 1 part. After miniplate osteosynthesis, more hypoaesthesia of the posterior superior alveolar nerve was observed than after wire osteosynthesis. The results are discussed and compared with the results found in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of the Cell Saver in transoral maxillofacial surgery: a preliminary report.

In a prospective study with 18 patients, the Cell Saver was used in transoral operations. Blood cultures were taken immediately before retransfusion, 15 min, 2 and 24 h after retransfusion. As a clinical consequence we noticed a higher increase in temperature because of the transient bacteraemia. Other negative clinical consequences were not observed. If adequate antibiotic prophylaxis is used with careful patient selection, we think that the Cell Saver can even be used in transoral operations, although the number of observations is too small to allow definitive conclusions.

Application of purified bone morphogenetic protein (BMP) preparations in cranio-maxillo-facial surgery. Reconstruction in craniofacial malformations and post-traumatic or operative defects of the skull with lyophilized cartilage and BMP.

New ways of craniofacial reconstruction in old post-traumatic or fresh donor site craniectomy defects and in congenital malformations (Apert's and Crouzon's syndromes) are described. In all instances a stacked composite of lyophilized cartilage strips interspersed with BMP layers was applied to fill the defects and indentations or used in combination with autologous bone struts to rebuild the cranium completely in synostotic malformations. The stratified implants interlaced with BMP induced early bone formation, and in addition were rigid enough from the beginning to serve as bridging elements over and between autologous bone struts in the cage-like forehead reconstructions. The reconstructed areas became clinically solid after a few months. CT images taken in 4 cases showed progressive calcification starting in the BMP layers, sometimes already visible after a few weeks. These results indicate that the usual slow process of calcification/ossification of lyocartilage alone is considerably accelerated by the combination with BMP. From intermediate term observations (more than one year) we conclude that complete consolidation of the whole implants, so far without signs of resorption, will consistently be the final outcome of this type of reconstruction.

A new method for the correction of hypertelorism with preservation of the olfactory nerve filaments.

A method for the preservation of the olfactory nerve filaments in cases of hypertelorism correction is described. The cribriform plate is completely resected and the nerve filaments gathered in the midline after medial rotation of the orbits. In contrast to Converse's (1970) procedure of paramedian osteotomies the method allows full correction of all degrees of hypertelorism, even in the most extreme cases, without olfactory nerve impairment.

Application of purified bone morphogenetic protein (BMP) in cranio-maxillo-facial surgery. BMP in compromised surgical reconstructions using titanium implants.

After a review of the clinically relevant literature on early modified whole bone products (demineralized bone; AAA bone (Urist et al., 1975))--predecessors of purified bone morphogenetic protein (BMP)--and a summary of the only published clinical experience with purified human BMP (in orthopedic surgery; from the group of Urist; Johnson et al., 1988-1992), an introductory overview of our experience with our own preparations of BMP from bovine bone in 271 procedures on the face and cranium in 145 patients is presented. In this first article of a series of three, major preprosthetic reconstructions using iliac bone grafts and titanium screw implants are described. All patients are examples of compromised bone and/or soft tissue conditions and cannot be considered routine indications for the operations performed. The most endangered implants became osseointegrated after 6 to 8 1/2 months as judged from clinical examination and CT imaging. These results demonstrate the efficacy of purified, concentrated BMP preparations, able unequivocally to induce bone even in areas with seemingly lost implants.

Seven years clinical experience with mandibular distraction in children.

Mandibular distraction was performed on 14 children, between September 1991 and December 1997. Their average age was 6.9 years, ranging from 1.5 to 13.5 years. All patients had severe hypoplastic mandibles with retromandibulism. Seven of the children (50%) had respiratory distress due to obstruction of the upper airway before distraction. This resolved in every case. Five patients underwent unilateral and nine bilateral distraction. A total of 23 distractors were used, 15 were applied extraorally and 8 endorally. The average latency time after operation was 2.8 days, but for the past 2 years, distraction was started beginning with the operation. The distraction was increased twice daily for an average of 5.5 weeks, by 0.4 or 0.5 mm each time, depending on the distractor. Computed tomography and ultrasound were used to follow the ossification process in the distraction gap and to measure the lengthening achieved. Subsequent retention time averaged 2.4 weeks. The mandibles were elongated by up to 18 mm (average 9.3 mm) and the respiratory distress symptoms resolved in all patients. Several minor complications which are reported occurred. Six patients were followed up for periods between 3 and 7 years. During this time further growth of the distracted mandibles was recorded.

Biodegradable self-reinforced poly-L/DL-lactide plates and screws in bimaxillary orthognathic surgery: short term skeletal stability and material related failures.

Biodegradable self-reinforced poly-L/DL-lactide plates and screws were used for osteosynthesis in 10 consecutive cases of bimaxillary procedures with simultaneous genioplasties, without postoperative rigid intermaxillary fixation. During surgery, data were gathered concerning failure of the osteosynthesis material. Clinical examination was carried out weekly until the sixth postoperative week. Cephalometric analysis of standardized cephalograms was performed to evaluate the short-term skeletal stability pattern, which was compared with similar reports in the literature. Six weeks postoperatively, all jaws were clinically stable and there was no clinical evidence of foreign body reactions. For the whole group (n = 10), the mean maxillary advancement at point A was 2.9 mm with a mean postoperative relapse of 0.0 mm. The mean advancement at point B was 2.8 mm with a mean additional advancement postoperatively of 1.1 mm. The mean vertical surgical displacement at point A was directed inferiorly with a value of 1.8 mm and a relapse of -0.4 mm. At point B the corresponding values were 1.9 mm and -0.4 mm. In the Angle Class III group (n = 4), the mean advancement at A was 5.9 mm with an additional postoperative advancement of 0.3 mm. In the Angle Class II group (n = 6), mean advancement at point B was 4.0 mm, with an additional postoperative advancement of 1.1 mm. In the group with short face deformity (n = 3), the mean inferior movement in ANS was 6.6 mm with a relapse of -0.2 mm. At menton the vertical surgical movement was 13.0 mm with a relapse of -0.2 mm. None of the plates, which were bent at room temperature, broke. The screw heads broke or had an insufficient fit in the bone in 12 of 305 (3.9%) screws. It can be concluded that the tested system of biodegradable self-reinforced poly-L/DL-lactide screws and plates has a small material-related failure rate, and that their application in orthognathic surgery leads to a predictable short-term skeletal stability pattern which is comparable to the 'gold standard' of titanium plates and screws.

A new method for assessing the temporomandibular joint quantitatively by dental scan.

The objective of this study was to assess the applicability of a multiplanar reformatting program (dental scan) for delineation and quantitative evaluation of the temporomandibular joint (TMJ) in the sagittal and coronal planes using the data of axial computed tomography. The resulting images were compared with standardized linear tomograms and direct sagittal and frontal computed tomography. Standardized linear tomograms and computed tomography of the TMJ in axial, frontal and sagittal planes were obtained in 11 patients. The axial computed tomography slices were then reconstructed in oblique frontal and sagittal planes according to the horizontal condylar angle of the TMJ by dental scan software. For each patient and each of the three imaging methods, 14 measurements were undertaken and 24 qualitative characterizations were assessed. Axial computed tomograms in combination with their corresponding coronal and sagittal reconstructions were more accurate than conventional tomograms. Direct coronal and sagittal scans gave the most detailed images, but required additional radiation dose, time and cost. Reconstructions of axial computed tomography slices of the TMJ using the dental scan software show several advantages over linear tomograms. They allow qualitative as well as quantitative evaluation of the TMJ.

The role of a posteriorly inclined condylar neck in condylar resorption after orthognathic surgery.

Recently, it has been reported that a posteriorly inclined condylar neck is associated with condylar resorption following orthognathic surgery, although its role in resorption remains unknown. By cephalometric screening of 240 patients with Angle Class II occlusion 2 years after orthognathic surgery, 11 patients with postoperative condylar resorption were identified. The preoperative posterior inclination of the condylar neck and the surgical risk factors mentioned in the literature, particularly surgically induced counterclockwise rotation of the mandibular proximal segment were evaluated. In all 11 cases, the condylar neck was clearly inclined posteriorly. Counterclockwise rotation of the proximal segment was also observed in all cases, and it amounted to 6.7 degrees (2.5-12 degrees) on average. The contributing role of a posteriorly inclined condylar neck in connection with surgical mandibular movement in postoperative condylar resorption is discussed.

Mandibular osteomyelitis: evaluation and staging in 18 patients, using magnetic resonance imaging, computed tomography and conventional radiographs.

Over a period of 3 years, 18 patients with mandibular osteomyelitis were prospectively investigated by conventional radiograph, computed tomography (CT) and in 6 cases by magnetic resonance imaging (MRI). The diagnosis was based on histology in 17 patients operated upon.

Complications following arthroscopy of the temporomandibular joint: analysis covering a 10-year period (451 arthroscopies).

451 arthroscopies of the temporomandibular joint (TMJ) have been performed on 373 patients during 10 years of clinical experience. The complication rate was low (1.77%). Most complications were transient, consisting mainly of temporary deficits of the 5th and 7th cranial nerves. No patient required arthrotomy because of complications, but one patient had to undergo angiography and embolization of a traumatic aneurysm of the superficial temporal artery secondary to arthroscopy.

Loose bodies in the temporomandibular joint. The advantages of arthroscopy.

Loose bodies are a rare cause of temporomandibular joint symptoms. Their main source is synovial chondromatosis. We report on clinical findings, diagnostic methods, treatment choices and outcome following the removal of loose bodies in 10 patients. Seven patients were evaluated and treated by means of arthroscopy, while in three patients open arthrotomy was performed. In five patients, no diagnostic imaging technique had demonstrated the presence of loose bodies prior to arthroscopy. In six patients, histology revealed synovial chondromatosis. In four patients, osteochondral fragments alone were found. Until now, the recommended treatment of choice for the removal of all loose bodies and of affected synovial tissue required open arthrotomy. We conclude that the advantages of arthroscopy consist in locating loose bodies that are not detectable radiologically and in reducing operative trauma.

Frontal sinus fractures: principles of treatment and long-term results after sinus obliteration with the use of lyophilized cartilage.

The most commonly used techniques for frontal sinus obliteration involve the implantation of an autogenous tissue graft: either fat, muscle or bone. Lyophilized allogenic cartilage due to its unique properties, such as the tendency to ossification and resistance to volume reduction, can be used as the material of choice for sinus obliteration. A clinical and radiological study of 66 patients operated on for frontal sinus fractures, between January 1 1988 through December 31 1995 was undertaken. Variables recorded included the aetiological factors, the clinical and radiological fracture features with the corresponding treatment modality, the association of frontal sinus fractures with intracranial involvement, the early and late postsurgical complications and the correlation between pre- and postoperative radiological findings. Obliteration of the frontal sinus with lyophilized cartilage chips was performed in 51 (77.3%) patients. The postsurgical evaluation showed no major complications. Revision of the frontal sinus was only required in one patient. The radiological findings verified the progressive calcification of the obliterated sinus. Allogenic lyophilized cartilage implantation offers distinct advantages in cases of severe frontal sinus trauma: 1. There is nearly unlimited availability of the material. 2. There is no need for a second operation field with the associated potential donor site morbidity. 3. The operation time is reduced due to the avoidance of a second operation on the donor site.

Distraction osteogenesis for lengthening of the hard palate: Part II. Histological study of the hard and soft palate after distraction.

To correct velopharyngeal incompetence, a new treatment concept was proposed in Distraction Osteogenesis for Lengthening of the Hard Palate: Part I (using lengthening of the hard and soft palate by distraction osteogenesis). Cephalometry and computed tomography showed successful elongation of the posterior hard palate with gradual calcification. Here the sequential use of fluorochrome markers (oxytetracycline, xylenol orange, DCAF [2,4-bis-N-N'-dicarboxymethyl aminomethyl fluorescein], and alizarin complexone) during the distraction and retention period is reported together with the histologic investigations using light and laser scan microscopy without prior demineralization. The experimental gap showed de novo osteogenesis in all dogs. The new bone was always in continuity with the original anterior and posterior palatal bone margins. It either bridged the experimental gap fully or left a small central zone of fibrous tissue, in which eventual ossification occurred. Several distinct zones could be distinguished: A small central zone was found with parallel strains of collagen fibers, oriented longitudinally in the direction of the distraction. Next to this zone a layer of undifferentiated mesenchymal precursor cells was seen in direct contact to newly formed bone. The next zone was coarse woven bone, showing a transition to mature lamellar bone through remodeling. No evidence of endochondral bone formation was found, i.e., all dogs showed exclusively intramembranous bone formation. The soft tissues showed no signs of alteration: in particular, there was no necrosis or scar formation. The soft tissues were not thinned but appeared to have followed the longitudinal displacement. In conclusion, gradual distraction osteogenesis of the hard palate could be a possible method for lengthening the palate to treat velopharyngeal incompetence.

The Le Fort I osteotomy as a surgical approach for removal of tumours of the midface.

Tumours of the midface and maxillary sinuses have been removed via multiple approaches. The most common approaches are those using incisions in the facial skin, especially in the case of malignant tumours. The Le Fort I procedure via an intraoral incision as described by Sailer in 1986 is a versatile alternative. Combined with a coronal approach and various osteotomies of the upper face it also allows removal of tumours extending into the orbits, the nasoethmoidal complex and the skull base. The versatility of the Le Fort I osteotomy as a surgical approach was analysed in 17 cases. This method is reliable and gives excellent access. Further advantages are the wide surgical exposure and the clear visibility of the resection margins, the absence of visible scars, the feasibility of combining this approach with reconstruction using the buccal fat pad and the possibility of simultaneous placement of bone grafts, insertion of endosseous implants or other preprosthetic procedures via the same incision.