Non-grafted versus grafted sinus lift procedures for implantation in the atrophic maxilla: a systematic review and meta-analysis of randomized controlled trials.

The aim of this systematic review and meta-analysis was to critically evaluate the currently existing clinical evidence on the efficacy of graftless maxillary sinus membrane elevation for implantation in the atrophic posterior maxilla. A search protocol without limitations to November 2020 was followed by two independent researchers. Randomized controlled trials using the lateral window approach for graftless sinus membrane elevation were included. Uncontrolled, retrospective, non-comparative studies, case reports, and experimental studies in animals or cadavers were excluded. The search identified 2777 studies. Critical selection by two independent researchers then led to the inclusion of a total of nine studies. A risk of bias assessment was applied using the revised Cochrane risk-of-bias tool for randomized trials. A meta-analysis was conducted for seven studies. Results showed a high overall implant survival rate in both the graftless and bone-grafted sinus lift groups (97.92% and 98.73%, respectively). The graftless sinus lift group showed a significantly lower vertical bone height gain, with a mean difference of -1.73mm (P=0.01), and a significantly lower bone density, with a mean difference of -94.7 HU (P<0.001). The implant stability quotient values did not differ significantly between the test and control groups (P=0.07).

Premature craniosynostosis--the role of skull base surgery in its correction. A surgical and radiological experience of 172 operated infants/children.

BACKGROUND: Most craniofacial abnormalities are non-syndromic craniosynostoses due to premature fusion of one or more craniofacial sutures. Functional impairment is caused either by a pathological growth pattern or increased intracranial pressure. The indications for surgery are to increase intracranial volume and to correct aesthetics. PATIENTS AND METHODS: We retrospectively reviewed 172 patients who had been operated on for premature craniosynostosis, including fronto-orbital advancement, from 1992 to 2002. Demographic data, clinical follow-up findings, and regular photo documentation were analyzed. RESULTS: After a mean follow-up of 6 years the overall outcome for those operated on within the first 6 months of life was satisfactory in 97%. The remaining 3% were reoperated at between 4 and 6 years of age. All cephalometric indices normalized postoperatively. Eight patients underwent SPECT studies which showed preoperative perfusion asymmetry corresponding to the fused sutures that were normalized following surgical decompression. No severe perioperative complications were seen. DISCUSSION: Cephalometric parameters represent an excellent method to compare the postoperative outcome. Standard skull base procedures need to be adapted carefully to the individual form of craniosynostosis to avoid an unfavourable result. Single Photon Emissin Computed Tomography (SPECT) studies give evidence that correction of single cranial suture synostosis allows for normalization of cerebral blood flow and should be performed within first 6-8 months of life.

[Evaluation of the postoperative clinical results of repositioning isolated zygomatic fractures]. / Beurteilung des postoperativen klinischen Repositionsergebnisses isolierter Jochbeinfrakturen.

This retrospective study included 148 patients who were evaluated for postoperative long-term results after osteosynthesis of isolated zygoma fractures. The influence of open reposition of the zygomaticoalveolar crest to middle face symmetry was evaluated quantitatively with a zygometer. In dependence on operative management patients were divided into two groups: In group I zygomaticofrontal suture (1-point-fixation) and infra-orbital rim were exposed (2-point-fixation), followed by osteosynthesis. In group II additional exposure of zygomaticoalveolar crest was performed and if required osteosynthesis was performed (3-point-fixation). For osteosynthetic reconstruction of isolated zygoma fractures the only 2-point-fixation is usually enough to achieve lateral middle face symmetry. In all cases zygomaticofrontal suture and alternatively infra-orbital rim or respectively zygomaticoalveolar crest should be supplied osteosynthetically. A further 3-point-fixation is indicated only in exceptional cases--for example comminuted fractures of lateral middle face columns. For an exact anatomical reposition of zygoma fractures the exposition and possible osteosynthesis of zygomaticoalveolar crest is recommended.

Piezoelectric bone surgery: a revolutionary technique for minimally invasive surgery in cranial base and spinal surgery? Technical note.

OBJECTIVE: Piezoelectric surgery represents an innovative, ultrasonic surgery technique for performing a safe and effective osteotomy or osteoplasty that contrasts with the traditional hard and soft tissue management methods with rotating instruments. METHODS: Because of its physical and mechanical properties, the definitive clinical advantage of piezoelectric bone surgery with regard to precision cutting lies in the sparing of vital neurovascular bundles or general soft tissue and better visualization of the surgical field, thus suggesting its great safety. Piezoelectric bone surgery has been previously described only in oral and maxillofacial operative procedures in adults. RESULTS: Five children between the age of 6 and 84 months were operated on for craniosynostosis, tethered cord, and an extraconal intraorbital tumor. The usefulness of piezoelectric bone surgery during neurosurgical procedures is presented for these cases. This technique is especially recommended when there are anatomic difficulties because of poor intraoperative visibility or the presence of delicate anatomic structures. CONCLUSION: The present preliminary report (comprising illustrative case reports) demonstrates and introduces for the first time the utility of piezoelectric bone surgery in cranial base and spinal surgery in children. Until now, there has been no documented neurosurgical experience of this technique even in adults.

Ultrasonic surgery--an alternative way in orthognathic surgery of the mandible. A pilot study.

The aim of this report is to present preliminary results and experiences using an ultrasonic bone-cutting device in bilateral sagittal split osteotomies of the mandible (BSSRO) with particular attention to possible damages to the inferior alveolar nerve (IAN). Seven patients with class II or class III malocclusion were treated by BSSRO with a conventional combined orthognathic and surgical approach. The osteotomy was carried out using an ultrasonic bone-cutting device. Subjective neurosensory deficits of the inferior alveolar nerve were assessed on 14 sides. Compared to the conventional techniques using saws, chisels and burs, the use of the ultrasonic device was more time-consuming, but the osteotomies were carried out at a high level of precision. In addition, this procedure offered the advantage of a blood-free surgical field and thus provided good control of the surgical procedure. Subjective neurosensory disturbances of the IAN showed a continuous decrease from 57.1% (eight sides) 2 months after the surgical procedure to 14.3% (2 sides) after 5 months and to 7.1% 7 months after BSSRO. Within the seven patients of this pilot study associated neurosensory disturbances were low. A possible advantage in terms of nerve protection is subject to a prospective study.

[Influence of different mixing fluids on mechanical and micromorphological in vitro qualities of hydroxyapatite cement]. / Einfluss unterschiedlicher Anrührflüssigkeiten auf die mechanischen und mikromorphologischen In-vitro-Eigenschaften von Hydroxylapatitzement.

AIM: In reconstructive craniofacial surgery a new synthetic hydroxyapatite cement has been used in the last few years. Tetra- and dicalcium phosphates react with either slow setting aqua bidest. or with faster setting sodium monophosphate solution to hydroxyapatite. The aim of this study was to investigate the two mixing fluids of hydroxyapatite for resulting micromorphology, pressure strength, and interactions with fibroblasts. MATERIAL AND METHODS: Pressure strength tests of hydroxyapatite cement test samples (n=80) were performed after a setting time of 3 and 24 h. The micromorphology of surfaces of the resulting particles was assessed under an electron microscope. In cell cultures L-929 and HEp2 cells were incubated with test samples and cell growth was assessed by light and electron microscopy. RESULTS: The test samples mixed with sodium monophosphate solution showed statistically significantly higher values of pressure strength. The resulting pressure strength depended on respective mixing fluids, setting time, and pressure of application. In general, test samples mixed with sodium monophosphate solution showed a more load-stable, homogeneous anorganic matrix whereas test samples mixed with aqua bidest. had a porous microarchitecture which was more fragile. In cell culture the porous structure showed disintegration in cell culture medium. CONCLUSION: To what extent the two mixing liquids of hydroxyapatite cement influence the resorption and bony substitution has to be shown in further studies.

Bioartificial bone grafting: Tarsal joint fusion in a dog using a bioartificial composite bone graft consisting of beta-tricalciumphosphate and platelet rich plasma--a case report.

Grafting of large bone defects caused by trauma or tumor resection still remains a problem to solve. In experimental studies as well as in human dentistry, osteoconduction and biodegradation of the beta-tricalciumphosphate Cerasorb as well as osteoinductive capabilities of platelet rich plasma have been proven. In case of luxation of the right tarsal joint, including a compressive fracture of the forth tarsal bone, the recommended use of autologous cancellous bone to support osseous fusion was replaced by the use of a bioartificial bone graft. Biodegradation of the bone graft was proven clinically and radiographically. Complete osseous fusion of the intertarsal joint occurred. The use of the beta-tricalciumphosphate Cerasorb in combination with platelet rich plasma to support a partial arthrodesis of the tarsal joint in a dog did not impede the healing process but led to full recovery of the patient, indicating that this concept of bioartificial bone grafting could support bone healing.

[Memory effect of resorbable polymers]. / Memory-Effekt resorbierbarer Polymere.

BACKGROUND: The present study analyzed the memory effect of resorbable polymers. Depending on temperature, this effect describes the ability of different materials to "remember" their original form after mechanical deformation. Resorbable polymers serve as materials to stabilize and fix bone fractures. Compared to metal transplants, resorbable polymers are able to undergo thermoplastic deformation. The precise adaptation of the transplant to the surrounding bone guarantees an exact anatomical reconstruction. However, during normal applications, it was observed that these biodegradable plastic materials tend to revert to their original form at body temperature. This "memory effect" could result in negative consequences for the medical treatment. METHODS: By the process of compression molding, geometrically formed specimens (lattice, rod, plate) consisting of different polyglycolides and polylactides were prepared. After warming up the specimens to 50 degrees C (water bath) they were deformed into definite angles. Following this procedure, the specimens were put in a water bath at 37 degrees C to mimic the adaptation of the transplant at body temperature. The retroflexion of the material (memory effect) was measured using an XY-measuring desk. RESULTS: The present study clearly reveals that highly deformed specimens react with stronger retroflexions. In addition, the results indicate that the memory effect depends on geometrical design as well as on chemical composition. All tested polymers showed a strong initial memory effect that decreased with time.

[Evaluation of B-scan ultrasound, 3-D ultrasound, roentgen diagnosis and sinus endoscopy in follow-up assessment of the maxillary sinus after sinus floor elevation]. / Evaluation der B-Scan-Sonographie, 3D-Sonographie, Röntgendiagnostik und Sinuskopie zur Kontrolle der Kieferhöhle nach Sinusbodenelevation.

PROBLEM: The aim of this study was to determine which technique--B-scan sonography, 3D sonography, X-ray, or endoscopy--is the most effective for diagnosis in changes of the maxillary sinus after sinus lift and simultaneous augmentation. MATERIAL AND METHODS: In 33 patients the maxillary sinus was examined before sinus lift, 1 week and 6 months postoperatively with a 7.5-MHz linear scanner and 3D sonography. At the same time, the sonographic results were compared with the X-ray as well as the endoscopic results. Endoscopy of the maxillary sinus was only applied during the sinus lift operation and the abutment operation after 6 months. RESULTS: A total of 56 operations of sinus lift and simultaneous augmentation with autogenous bone were carried out. Preoperatively, there where no pathological findings detectable in the maxillary sinus. One week postoperatively, the X-rays as well as the sonographic images revealed thickening of the mucosa in 40 maxillary sinuses. After the healing period of 6 months, polyposa was still detected in three cases sonographically, in the radiographic follow-up as well as endoscopically. The sonographic 3D imaging of the maxillary sinus improved the spatial visualization of postoperative changes in the maxillary sinus and the reliability of the diagnosis. CONCLUSION: Due to the lack of radiation, the cost effectiveness, and its reproducibility, sonography is suitable as a primary screening technique in recall. In cases of normal sonographic findings but clinical symptoms, CT, MRT, and endoscopy should be performed to exclude pathological processes of the posterior maxillary sinus.

[Multislice helical CT (MSCT) for mid-facial trauma: Optimization of parameters for scanning and reconstruction]. / Mehrschicht-Spiral-CT (MSCT) beim Mittelgesichtstrauma: Optimierung der Aufnahme- und Rekonstruktionsparameter.

PURPOSE: To determine the optimal scan parameters in multislice helical CT (MSCT) of the facial bone complex for both axial scanning and multiplanar reconstructions. MATERIAL AND METHODS: An anthropomorphic skull phantom was examined with a MSCT. Axial scans were performed with continuously increasing collimations (4 x 1.25 - 4 x 2.5 mm), tube current (20 - 200 mA) and table speeds (3.75 mm/rot. and 7.5 mm/rot.). Multiplanar reconstructions in coronal and parasagittal planes with different reconstruction increment and slice thickness were evaluated in terms of image noise, contour artifacts and visualisation of anatomical structures. RESULTS: The best image quality was obtained with a collimation of 4 x 1.25 mm and a table speed of 3.75 mm/rot. A reconstruction increment of 0.6 mm achieved the best time to image quality relation. With these parameters the bone structures were depicted in an optimal way without artifacts. The tube current could be reduced to 50 mA without significant loss of image quality. The optimized protocol was used for regular routine examinations in patients with facial trauma (n = 66). CONCLUSIONS: Low-dose MSCT using thin collimation, low table speed and small reconstruction increments provides excellent data for both axial images and multiplanar reconstructions in patients with facial trauma. An additional examination in coronal orientation is therefore no longer necessary.

[Renaissance of the Franz König bilateral lip repair procedure - clinical experiences with an one hundred year old technique]. / Die Renaissance des doppelseitigen Lippenspaltverschluss nach Franz König - Klinische Erfahrungen mit einer über hundert Jahre alten Technik -

Surgical correction of bilateral cleft lips is known to have a lot of problems. The surgical principles of treatment of bilateral cleft lips are similar to those of unilateral clefts but differ in the area of the prolabium due to specific anatomical disorders of the orbicularis oris muscle. The postoperative results of simultaneous bilateral cleft lip repair according to König were analysed retrospectively in 15 young children (6.1 +/- 1.1 years) paying special emphasis to the aesthetic and functional postoperative outcome of the upper lip and nose. The mean values were compared with measurements from normal infants at ages 8.3 +/- 1.8 years. Lip height and lip length were in 87 % similar to those of the age-matched normal group. Only two cleft patients showed a slightly shorter lip. Distortions of the lip function were not obvious. Our data show that König's surgical procedure of bilateral cleft lip closure meets the requirements of modern surgical concepts of cleft lip repair and should belong to the armamentarium of modern face surgery.

Degradation characteristics of alpha and beta tri-calcium-phosphate (TCP) in minipigs.

In seven Goettingen minipigs 3.5--4.7-ml cancellous bone defects were created in the area of the tibial head on both sides. The defects were filled with alpha-TCP or beta-TCP (tricalciumphosphate). ITI implants (Straumann, Freiburg, Germany) of 3.2 x 12-mm length were inserted into the underlying ceramic substitutes. Two additional pigs were used as control. Within the periods of observation (4, 16, 20, 28, 46, 68, and 86 weeks) fluorescent dyes were applied. Nondecalcified thin-sliced sections were examined by means of light and fluorescence microscopy. In addition microangiography and microradiography were performed. Bony regeneration occurred basally and on the sides of the defect according the angiogenetic reossification pattern. Resorption was due to a hydrolytic and cellular degradation process. After 46 weeks histomorphological evaluation showed an incomplete osseointegration of the simultaneously implanted dental implants. The bone contact surface ratio was lower than 25%. After 86 weeks 95--97% of both alpha- and beta-TCP were resorbed. Ceramic residuals stayed within the newly formed trabeculae thus resisting further degradation until remodeling occurred. Both alpha- and beta-TCP show a comparable degradation process. At the 86-week postoperative point only small residuals of the ceramic can be found. These residuals stay within the newly formed trabeculae, which show a functional orientation. In comparison control defects showed only sparse reossification. The beta-TCP material shows an accelerated degradation mode and has an optimal reactivity with the surrounding tissues. According to the results of this animal experiment both materials can be classified as bone-rebuilding materials.

Correction of skull defects using hydroxyapatite cement (HAC)--evidence derived from animal experiments and clinical experience.

BACKGROUND: The development of satisfactory cranioplasty material and technique has been a continuing bio-engineering challenge. Cranial defects resulting from trauma, tumour or infection are most frequently reconstructed with nonviable alloplastic materials. At present, all synthetic or biological materials in the use for human cranioplasty are more or less ideal. METHODS: The in vivo properties of a fully resorbable bony substitute--hydroxyapatite cement (HAC, BoneSource) are described in clinical investigations and animal experiments. HAC is prepared from calcium phosphate precursors which are hydrated and harden endothermically at 37 degrees C to form hydroxyapatite. Bone formation and resorption characteristics of HAC are examined in an adult minipig cranial defect model. FINDINGS: Cranial bone integrity has been restored in ten of eleven patients. Radiographic examination 6 months after surgery reveal a successful reconstruction of the skull defects. Sections of the cranial defect site from animals sacrificed at 12, 18 and 40 weeks demonstrate that new bone formation proceeds in HAC filled osseous defects. Histomorphological evaluation of HAC resorption and new bone formation indicates that HAC is nearly completely resorbed within 40 weeks and replaced by new bone with no loss in size or volume. INTERPRETATION: Hydroxyapatite cement (HAC) has an excellent biocompatibility (non-immunogenic and non-toxic), seems to be an optimal implant for cranial reconstruction and provides a biological scaffold for bone formation. However, further studies need to be conducted to determine the long-term stability of HAC.

Subgaleal versus subperiosteal dissection in fronto-orbital advancement procedures.

Extensive cranioorbital surgery for craniosynostosis in young children can produce excessive blood loss. Thus, to overcome the disadvantage of unappropriated blood loss and translocation of the osteosynthesis material, we performed a subgaleal dissection in infants and compared the subperiosteal with the subgaleal surgical approach in 29 children who underwent surgery for craniosynostosis. The treatment goal of correction of the deformity was accomplished in each case. Fronto-orbital deformities were significantly improved in all patients. Blood loss was less in the group with subgaleal elevation of the forehead (mean = 163 ml) compared with the subperiosteal group, which had a mean 266 ml blood loss. The subgaleal dissection caused less bleeding and tethering of the advanced bone.

Intraindividual comparative animal study of alpha- and beta-tricalcium phosphate degradation in conjunction with simultaneous insertion of dental implants.

An intraindividual comparative study of proximal tibial marrow defects in nine adult Goettinger miniature pigs (GMPs) was undertaken. The left side of the defect was filled with granular beta-tricalcium phosphate (TCP) ceramic ad modum Cerasorb, and the right side was filled with granular alpha-TCP ceramic ad modum Biobase alpha pore. Simultaneously, dental screw implants were inserted in each ceramic and fixed within the orthotopically replanted corticalis lids. Control defects were made in two other animals. The survival period ranged from 4 to 86 weeks (control study, 16 and 20 weeks). The reorganization and degree of bone regeneration, dynamics of ceramic degradation, and remodeling characteristics of the bone regenerate referring to osseo-integration of the dental implants were examined histomorphologically in nondecalcified specimens. The results reveal that both ceramic types were osteoconductive exclusively. Centripetally oriented angiogene bone regeneration occurred at the margins of the circular defects. Ceramic degradation was performed hydrolytically and within cells. Furthermore, it was demonstrated that decomposition of the intratrabecularly integrated ceramic residues underlies a dynamic process of degradation. Within 86 weeks, nearly 80% to 90% of the larger alpha-TCP granules, and nearly 90% to 95% of the beta-TCP granules were degraded. At this time, especially for the alpha-TCP modification, ceramic microparticles were found in the marrow, either unbound or within polynuclear macrophages. The predictable degradation of both ceramic types provides an early functional adaptation of bone regenerates and facilitates a biofunctional, anisotropic orientation of the neotrabeculae without delay. It is concluded that because of the initially pronounced accumulation of macrophages, dental implants should not be inserted simultaneously with ceramic, but after further progress of ceramic degradation (5 to 6 months after TCP implantation).

Continuous and intermittent bone distraction using a microhydraulic cylinder: an experimental study in minipigs.

Distraction osteogenesis of the mandible is an option in the treatment of mandibular hypoplasia. Today, only intermittent distraction devices are available for clinical application. The aim of this study in minipigs was to evaluate continuous bone distraction using a microhydraulic cylinder. After a seven-day interval, continuous or intermittent distraction of 1.5 mm/day was established for 10 days. Immediately after active distraction, two animals and 20 days later the other four animals were killed and radiographs taken. The mandible was then removed en bloc and the distracted bone examined histologically. Intermittent distraction forces of up to 2500 kPa were necessary to move the cylinders' piston. The pressure needed for continuous distraction was considerably lower (1200-1300 kPa). While the specific histological structure of the varying zones in the distraction gap was similar after continuous and intermittent distraction, bone healing was accelerated after continuous distraction as shown by ultrasonography and scanning electron microscopy.

[Intra-individual comparison of alpha- and beta-TCP ceramics in an animal experiment]. / Intraindividueller Vergleich von alpha- und beta-TCP-Keramik im Tierexperiment.

In the quest for bioinert adaptable alloplastic materials, TCP ceramics have gained a new application in craniofacial bone substitutes. Therefore, a histomorphological, intraindividual, comparative study was conducted on seven adult Goettingen miniature pigs (GMP) to analyze the difference of the degradation and remodelling processes of alpha-TCP and beta-TCP in critical size defects of the proximal tibiae. In addition, primary insertion of dental implants followed to study osseous integration. The critical size defects, which were created in the proximal tibiae in GMPs, were filled on the left side with beta-TCP and on the right side with alpha-TCP. Two GMPs were used as control group. After 4-68 weeks of investigation, the GMPs were sacrificed by narcosis. The histological investigation showed that these ceramics have an osteoconductive effect. It was noted that ossification proceeds centripetally. It could be demonstrated that the degradation of the materials follows a hydrolytical process and that the intratrabecular integrated ceramic remnants follow a dynamic remodelling process. Within 68 weeks after implantation, 90% of the TCP granulae were degraded. Macrophages were found in the marrow space, containing microparticles of TCP, especially after alpha-TCP implantation. In conclusion, defined degradation of these ceramics allows early functional bone regeneration with an additional undisturbed biofunctional unisotrop orientation of new trabeculae. Furthermore, dental implants should be inserted 5-6 months after TCP implantation.