Biomedical subjects

H Schliephake

Publications and source records attributed to H Schliephake.

At least 55 records · Page 3Linked to original sources

PubMed1999

Long-term results of endosteal implants used for restoration of oral function after oncologic surgery.

The aim of the present study was to analyse the long-term survival rate of endosteal implants used for restoration of oral function in patients having undergone oncologic surgery. Eighty-three consecutive patients, who had received a total of 409 endosteal implants ad modum Brånemark, subsequent to resections of soft tissue and bone during ablation of oral malignancies, were enrolled into the study. A life-table analysis was used to determine the survival rate of the implants placed during a period of 13 years. Log rank tests and Cox regression analysis were employed to identify relevant effects of surgical parameters on implant survival. A total of 38 implant failures were encountered. Most of the losses (n = 19) occurred during the first year of functional loading. Subsequent failures were evenly distributed across the remaining follow-up period. The cumulative overall survival rate of implants was 56.5%. Previous radiation therapy, insertion into grafted bone or original jaw bone and the technique of grafting did not significantly affect the survival rates. In the Cox regression analysis, the timing of implant placement in the group of patients with bone grafts (primary vs. secondary placement) was significantly related to the survival rate (P = 0.0197), with a lower survival rate of 36.2% for primary insertion of implants and 67.1% for secondary placement.

Adolescent↗

PubMed1999

Long-term results of the use of silicone sheets after diskectomy in the temporomandibular joint: clinical, radiographic and histopathologic findings.

The aim of the present study was to evaluate the long-term results of a group of patients who had the disk of the temporomandibular joint (TMJ) removed and permanently replaced by a silicone sheet. The study group comprised 48 patients, treated in the period from 1983 to 1993. In eight patients, the implants had to be removed after an average interval of 5.6 years and they were submitted for histopathological examination. Twenty-five of the 40 patients with silastic implants in place, and five of the 8 patients who had their implants removed, were available for long-term follow-up (mean interval of 7.0 years, SD 2.8 years). Clinical function was rated according to the Helkimo Dysfunction Index and compared to the preoperative findings. Results showed decreased tenderness of muscles and joints to palpation and increased mouth opening, but no statistically significant improvement in joint function. In 4 patients, a decrease in condylar width was found, while another 4 patients presented with thickening of the condyle by appositional bone formation. Histopathology of the failed implants showed scattered fragments of silastic material and dacron fibers with accumulation of histiocytes in immediate contact with the silicone particles and phagocytozed intracellular material. T-lymphocytes were also present in the vicinity of the silicone particles.

Adult↗

PubMed1999

Monitoring of graft perfusion and osteoblast activity in revascularised fibula segments using [18F]-positron emission tomography.

The aim of the present study was to evaluate healing of revascularised fibula grafts used for mandibular reconstruction using [18F]fluoride ion and positron emission tomography (PET). Sixteen PET studies in 11 fibula grafts were analysed to determine both blood flow and fluoride influx as a measure of vascularisation and osteogenic activity. Two graft failures and three non-unions were encountered and were compared to the successfully healed grafts. In uneventful graft healing, early PET studies (on average 19 days after grafting) showed a significantly increased blood flow to the grafted bone and to the union between the grafts and the mandibles when compared to the reference region of the cervical spine. In contrast, fluoride influx was significantly lower in the grafts when compared to the plating area and the cervical spine. Six months after grafting, blood flow to the grafted bone and the mandibular bone had returned to a level comparable with the reference region. Fluoride influx remained significantly lower in the grafts than in the plating areas or cervical spines. Graft failures were associated with negligible fluoride influx near zero in early PET studies. These results suggest that revascularised fibula grafts provide a low osteogenic potential, presumably due to the pre-existing lack of cancellous bone. The relatively high frequency of non-unions makes meticulous adaptation of the graft and the mandible mandatory, particularly in patients with compromised viability of the recipient bone.

Bone Plates↗

PubMed1998

[Experiences with distraction osteogenesis in therapy of severe peripheral airway obstruction in infancy and early childhood].

Children with craniofacial malformations are at special risk for the development of peripheral airway obstruction. The problems are magnified in patients with retroposition or hypoplasia of the mandible. In these cases, the base of the tongue is posteriorly displaced, hereby decreasing the airway diameter. By application of distraction osteogenesis the mandible can be lengthened to move the base of the tongue forward and open the airway. Three female patients aged between 7, 11, and 15 months suffering from peripheral airway obstruction caused by mandibular hypoplasia were treated by gradual distraction. All of them had a gastrostomy or a nasogastral tube in place, respectively, due to severe nutrition problems. In the youngest patient tracheostomy was performed shortly after birth and was already planned in the 15-month-old child, who had received a permanent nasopharyngeal tube. The 11-month-old child suffered from severe refractory sleep apnea. Exercises in oral feeding were possible in the youngest patient after 10 days of distraction. In the oldest one, the airway tube was removed on the six day of distraction and, thus, tracheotomy was successfully avoided. In the 11-month-old child apneic events a rapidly decreased. Our experience suggests that distraction osteogenesis after careful preoperative evaluation can be successfully performed for the treatment of peripheral airway obstruction in patients with selected craniofacial anomalies.

Airway Obstruction↗

PubMed1998

Experimental reconstruction of the mandible using polylactic acid tubes and basic fibroblast growth factor in alloplastic scaffolds.

PURPOSE: This study evaluated the use of a mitogenic growth factor in combination with barrier membranes and porous alloplastic scaffolds for the repair of segmental defects of the mandible. MATERIALS AND METHODS: Fifteen Göttingen minipigs were used for the study. In five animals, mandibular defects of 2 cm were created on both sides of the mandible and bridged by a system of polylactic acid (PLA) tubes and pyrolized bovine bone. On one side of the mandible, the alloplastic scaffolds were loaded with 115 microg recombinant human basic fibroblast growth factor (rhbFGF). In five other animals, defects 4 cm in length were created bilaterally, similarly bridged, and loaded with 230 microg of rhFGF. In five control animals, bilateral 2-cm defects were created that were left empty on one side and bridged with an empty PLA tube on the other. Mitogenic efficacy of the growth factor was assessed on fibroblast cultures by di-methyl-thiazol-2-tetrazolium-bromide assay before implantation. RESULTS: After 5 months, there was negligible bone regeneration in the control defects, regardless of whether they had been left completely empty or bridged by empty PLA tubes. The 2-cm defects showed bridging in 8 of 10 tubes, with complete consolidation by bone ingrowth in four defects. The 4-cm defects showed bony union in six cases, with complete bone fill in two tubes, and four defects incompletely filled. The bFGF had no appreciable effect with regard to velocity, quantity, and three-dimensional structure of bone formation, neither in the short nor in the long defects despite clear in vitro efficacy. CONCLUSION: Repair of segmental defects using bioresorbable membranes appears to be possible. However, a single-dose application of bFGF is apparently ineffective, possibly because of rapid dilution.

Animals↗

PubMed1998

Speech, deglutition and life quality after intraoral tumour resection. A prospective study.

The aim of the present prospective study was to evaluate the functional sequelae and postoperative development of quality of life after intraoral tumour surgery in 40 consecutive patients with a squamous cell carcinoma of the floor of the mouth. Immediate reconstruction of intraoral soft tissues after tumour resection was accomplished by local flaps (cheek and tongue) (n=27) and by revascularized transfer of small bowel grafts (n=5) and myocutaneous/fasciocutaneous flaps (n=8). Mobility of the tongue was assessed by ultrasound. Quality of speech was analysed using the Freiburg speech intelligibility test. Life quality was assessed by the functional living index-cancer preoperatively and six months postoperatively. A significant decrease in both mobility of the tongue and quality of speech was registered. The most substantial effect on quality of speech resulted from decreased movement of the base and the dorsum of the tongue. A significant increase in life quality at the end of the study period occurred only in the group of patients without substantial reduction of intelligibility of speech, while no significant improvement of postoperative life quality of patients with more severe deterioration of speech quality was found.

Adult↗

PubMed1998

Interdisciplinary microvascular reconstruction of maxillary, midfacial and skull base defects.

Microvascular reconstruction techniques are increasingly used for reconstructive purposes in the maxilla, the midface and the cranial base. In the maxillary area, they provide the possibility of a safe closure of nasoantral perforations which are too large for local coverage with or without additional bony reconstruction (n = 14). A basis for prosthodontic rehabilitation with implant-borne dentures is also provided. Additional free bone grafts are often a prerequisite for implant insertion. In reconstruction of the midface, microvascular techniques can separate functional units, provide tissue augmentation and give orbital support (n = 12). In skull base and cranial defects, a safe coverage of duraplasties and scalp reconstructions is achieved (n = 9).

Adolescent↗

PubMed1998

Evaluation of bone healing in patients with bone grafts and endosseous implants using single photon emission tomography (SPECT).

The aim of the present study was to evaluate the healing of onlay grafts to edentulous jaws in conjunction with osseointegrated implants using single photon emission computed tomography (SPECT). In all, 24 patients were examined who had received 26 full arch onlay grafts for augmentation of extremely atrophic edentulous jaws with secondary placement of implants 21.4 weeks after grafting. 99m-technetium-MDP scintigrams were performed immediately after grafting, before implant placement, after implant placement and before abutment connection. Tracer accumulation was assessed semiquantitatively by calculating ratios of count densities between the uptake over the calvarium and over the grafted jaws based on 16 regions of interest in the reconstructed tomograms corresponding to 16 possible areas of implant placement. There was a significant decrease in tracer uptake during graft healing, which was followed by a significant increase after implant placement and a subsequent decrease during implant healing. In 3 patients, infection and partial necrosis of the grafted bone occurred. In these cases, tracer uptake in areas of subsequent graft infection immediately after grafting was significantly lower compared to patients with uneventful healing as a sign of inferior graft revascularization. In 3 patients, 14 implants failed due to mobility at the time of abutment connection or loss of osseointegration within the first weeks thereafter. Significantly lower levels of tracer uptake immediately after grafting and during graft healing were found in these areas, representing a lack of bone turnover due to decreased revascularization. These areas also showed a lower increase in tracer accumulation after implant placement due to the inferior graft quality, followed by a significant increase of peri-implant bone turnover at the time of abutment connection representing inflammatory peri-implant bone reaction.

Adult↗

PubMed1997

[Cytokines and cytokine receptors in mouth mucosa of immune suppressed patients].

In vitro studies on epithelial cells suggest that cyclosporin (CsA) inhibits a pathway of production of IL-6, which is mediated by TNF alpha and E. coli. The aim of the present immunohistochemical study was therefore to evaluate the content and location of cytokines and cytokine receptors in the oral mucosa of 10 patients with CsA medication. Ten patients without immunosuppression served as controls. Specimens were procured during surgical treatment and processed by paraffin embedding and as cryosections. Expression of TNF alpha, IL-1 beta and IL-6-receptor was present both in the epithelial layer and the submucosal tissues, but did not differ very greatly between patients with CsA therapy and the controls. IL-6, however, displayed a positive reaction only in the control group, while it was invisible in the group of patients with CsA medication. The immunohistochemical findings of the present study suggest that there may be a lack of mucosal expression of IL-6 under CsA medication. With regard to the broad spectrum of possible effects of proinflammatory cytokines and their multiple interactions, the functional relevance of these findings merits further investigation.

Cyclosporine↗

PubMed1997

Reconstruction of calvarial defects by bioresorbable ceramics: an experimental study in rats.

This study evaluated bioresorbable ceramics in the reconstruction of calvarial defects. Full-thickness defects were made in the calvaria of 40 adult Sprague-Dawley rats (350-450 g) with a standard 8-mm trephine drill. Three different materials were used for defect repair: (a) pure alpha-tricalcium phosphate (TCP), (b) surface-treated glass ceramic, (c) surface-treated glass ceramic plus 70/30 L/DL polylactic acid (volume ratio 45/55). The implants were pellets of 7.9 mm diameter and 2 mm thickness and were inserted press fit into the calvarial defects. Each of these materials was inserted into ten animals. Five animals were evaluated each after 6 weeks and 26 weeks. For each interval there was a control group of five animals. After 6 weeks the control defects exhibited negligible bone regeneration at the defect margins but showed substantially more bone regeneration after 26 weeks extending up to 2.5 mm into the defect space. The TCP specimens showed a number of multinuclear cells on the material surface and direct bone/implant contact in a few locations but no signs of gross degradation or volume reduction after 6 weeks. The amount of bone ingrowth and cellular behavior had not changed after 26 weeks with resorption still going on. Glass ceramic implants by contrast appeared to be even better tolerated after 6 weeks with remarkable bone ingrowth and broad osseous fixation of the pellet to the defect margins and beyond, while highly vascular connective tissue filled the remaining pores of the implant. After 26 weeks the material had been extensively degraded, leaving behind only a few remnants, which were surrounded by seams of highly vascularized and cell-rich resorptive connective tissue with newly formed bone tissue nearly bridging the defect. The polylactic acid/ceramic composite implants showed hardly any tissue ingrowth or degradation either after 6 or after 26 weeks. Hence all tested materials appeared to be well tolerated at the site of implantation. However, gradual replacement by bone ingrowth tended to occur only in implants without polylactic acid.

Animals↗

PubMed1997

Survival analysis of endosseous implants in bone grafts used for the treatment of severe alveolar ridge atrophy.

PURPOSE: The aim of the current study was to evaluate the long-term results of endosseous implants placed into autogenous bone grafts in severely atrophic alveolar ridges. PATIENTS AND METHODS: A total of 871 implants were placed in 137 patients. The success rate was determined using survival analysis, log rank tests, and a cox regression analysis. RESULTS: Seventy-four implant failures were encountered in 23 patients. Most implants were lost because of a lack of osseointegration at the time of abutment connection or by asymptomatic loosening during the first months thereafter. The overall 1-year cumulative survival rate (CSR) was 83.4%, with a decrease to 67.8% after 5 years. The only parameter of prognostic relevance in the multivariate analysis of the whole study population was the patients' gender, with a significantly worse prognosis in female patients (5-year CSR, 62.3%). However, when the patients were divided into edentulous and partially edentulous jaws, a change was observed in the overall significance of the parameters introduced into the analysis. In edentulous patients, the maxilla appeared to over-rule all other parameters, with a 5-year cumulative survival rate of 48.8%, whereas the mandible presented a significantly higher rate of implant survival (5-year CSR, 89.3%). CONCLUSION: This study shows a poorer success rate in females than in males, probably because of differences in the quality of the bone grafts.

Adolescent↗

PubMed1997

Reconstruction of the mandible by prefabricated autogenous bone grafts. An experimental study in minipigs.

The aim of the present experimental study was to evaluate the use of prefabricated bone grafts for reconstruction of the mandible. In 20 adult Göttingen minipigs, prefabricated bone grafts 10 x 12 x 40 mm in size were cultivated in scaffolds of pyrolized bovine bone under a polylactic membrane on the outside of the mandible during a period of five months. The grafts were harvested and transferred to bridge 2- and 4-cm lower mandibular border defects and discontinuity defects. Five animals served as ungrafted controls and evaluation of the grafts was performed three and five months after grafting. At both intervals and in both graft-length groups, the grafted bone volume was almost completely preserved inside the scaffolds and exhibited a slight (3 months) to marked (5 months) increase in bone density by appositional bone growth. The inserted screws were histologically integrated into the transplanted bone and the grafts were linked to the adjacent mandibular bone without intervening soft tissue. The grafts, which were transferred to bridge discontinuity defects, were likewise well preserved with direct fusion between the grafted bone and local bone. It was concluded that bone grafts can be prefabricated from underlying mandibular bone and used for the repair of mandibular defects of various length and shape.

Animals↗

PubMed1997

Use of sequential bone scintigraphy for monitoring onlay grafts to grossly atrophic jaws.

OBJECTIVES: To evaluate the capability of sequential bone scintigraphy for assessing the viability of avascular onlay grafts in combination with primary or secondary implant placement. METHODS: Forty-six patients with severe alveolar ridge atrophy received full-arch onlay grafts from the iliac crest. Twenty patients received primary insertion of endosseous implants, while secondary implant placement was performed in 26 patients after an average interval of 95 days. In cases of primary implant placement, bone scintigraphy was performed after grafting and before abutment connection. In patients with secondary insertion, bone scans were performed after grafting, before and after implant placement and before abutment connection. For bone scintigraphy, 8 MBq 99mTc-MDP/kg body weight were administered intravenously and anterior views of the skull were obtained 3 h later. Regions of interest were drawn over the grafted area and over the calvarium as a reference area. Ratios of count densities between jaw and calvarium were calculated as a measure of tracer uptake. RESULTS: Bone grafts with primary insertion of implants showed a significant decrease (P = 0.0001) in ratios calculated for the whole graft from a mean of 3.53 after grafting to 2.35 before abutment connection. In cases of secondary implant placement, ratios decreased significantly after grafting from 4.04 to 2.78 before implant placement (P = 0.0001). After implant placement, there was a significant increase to 3.28 (P = 0.0062), which was followed again by a significant decrease to a mean ratio of 2.58 (P = 0.0437). CONCLUSIONS: Sequential bone scintigrams can provide information about the viability of the graft at the time of implant insertion and may thus indicate the ability of the grafted bone to accomplish osseointegration.

Adult↗

PubMed1997

[Restoration of the contour of the lower face by reconstruction of the mandible after tumor resection].

We evaluated the restoration of mandibular contour in 44 patients after continuity reconstructions of the mandible following tumor surgery. Average values of the lateral dimensions of both the mandible and overlying soft tissue were determined from serial CT scans in defined planes through the reconstructed mandible and showed satisfactory restoration of the lateral mandibular contour. The sagittal projection, however, showed a deficit in average values. The lack of sagittal projection and the fact that the lateral contour may also vary considerably in individual cases are due to unfavorable soft tissue conditions in secondary reconstruction cases. Meticulous preoperative evaluation is necessary in these cases to allow for exact determination of the desired size and position of the graft to make restoration of symmetry and projection of the lower third of the face more reliable.

Bone Transplantation↗

PubMed1997

[Facial asymmetry after vascular pedicled muscle transfer. Additional criterion for evaluating outcome in managing chronic facial paralysis].

Today neurotization and muscle transplantation are considered an ideal method of reconstructing the function of the facial nerve and the mimetic muscles in long-established facial palsy. Transplantation of the gracilis muscle as a segmental muscle provides an appropriate size for the face; however, determining the amount of muscle is difficult in order to obtain the desired dynamic and symmetric results. Prompted by the question of an "ideal" transplant size, a retrospective study was undertaken. Since 1991, 11 microneurovascular gracilis muscle transfers have been performed in 10 patients with long-established facial palsy (one patient underwent an additional transfer due to excessive scarring in a severe case of neurofibromatosis). Computed axial tomography scans were performed on six patients using a method for obtaining muscle-volume measurements of corresponding areas in each individual by using bony landmarks for reference. Cross-section area measurements by a digitalized mode were obtained from each scan, determining 20-70 Hounsfield units as appropriate for muscle tissue. Muscle-volume measurements ranged on the transplantation sites between 3.85 and 62 cm3 compared to 1.4 and 22.3 mm3 for the corresponding sites. The increments in muscular tissue by a factor between 2 and 3 are due to an increase in each single scan of the corresponding sides: when comparing the corresponding operated and unoperated sides in each patient, soft-tissue volumes were significantly (P < 0.005) elevated on the operated side. The findings presented in this study demonstrate not only encouraging functional results, but also show significant improvement of facial symmetry at rest. The results of our investigation support those of other authors, who also saw the main difficulty as determining the appropriate graft size. Secondary corrective procedures of the muscle puts the pedicle at risk of vascular and neural damage. Meticulous shaping of the graft and proper fixation and suspension technique cannot be overemphasized.

Chronic Disease↗

PubMed1997

[Profile modification of the middle and lower face after anterior onlay osteoplasty in severe atrophy of the maxilla].

A retrospective study was performed to evaluate hard- and soft-tissue changes after onlay bone grafts in atrophic maxillae. The assessment included 49 patients who received bone grafts from the iliac crest. Lateral cephalograms were taken pre- and postoperatively and analyzed by the Dentofacial Planner System. Sagittal hard tissue changes from 2.3 to 3.5 mm (p < 0.01) in an anterior direction were found. Soft-tissue advancements from 2.3 mm (p = 0.0039) to 2.7 mm (p = 0.0018) were measured. The relationship of soft-tissue changes to hard-tissue changes ranged from 0.7:1 to 0.9:1.

Adult↗

PubMed1996

The free revascularized rectus abdominis myocutaneous flap for the repair of tumour related defects in the head and neck area.

The present work reviews a series of 11 consecutive patients who have received free revascularized rectus abdominis myocutaneous flaps for primary reconstruction of soft tissues after ablative tumour surgery in the head and neck area. In 10 patients, a total or subtotal glossectomy had been performed and the flap was used to replace the resected tongue volume. In 5 of these cases, extensive perforating defects had resulted after additional resection of large portions of the chin and the cheek. Mandibular continuity was restored by a metal plate and the flap was divided into an intraoral and extraoral portion in these patients. In one patient, the flap had been used for closure of a full thickness defect of the calvarium. 9 of the 11 flaps healed uneventfully. In one case, a partial flap loss was encountered after thrombosis of the venous pedicle due to compression as a result of an unfavourable defect anatomy and flap positioning. Primary closure of the abdominal wall was achieved in all cases. A subcutaneous hematoma occurred at the donor site in one patient. According to our present experience, the rectus abdominis free flap may serve as an alternative to the frequently employed latissimus dorsi flap in maxillofacial reconstructions while it offers the possibility for flap elevation simultaneously to the surgical procedures in the head and neck area.

Arteries↗

PubMed1996

Prospective study of the quality of life of cancer patients after intraoral tumor surgery.

PURPOSE: The aim of this prospective study was to determine the quality of life of patients with oral cancer after intraoral ablative surgery. PATIENTS AND METHODS: Eighty-five consecutive patients with squamous cell carcinoma of the floor of the mouth were enrolled in the study. Reconstruction of intraoral soft tissues was accomplished by local tissue (67.8%), jejunal grafts (16.9%), and cutaneous and myocutaneous flaps (15.3%). Soft tissue resections were combined with resections of the alveolar process of the mandible in 35.0% and mandibular discontinuity resections in 31.7% of the cases. A self-administered, standard questionnaire consisting of 22 visual analog scale items with a maximum index value of 154 was used to determine the physical functional status, the psychological status, and social functioning of cancer patients (Functional Living Index--Cancer). The questionnaire was administered preoperatively and 3, 6, and 12 months postoperatively. RESULTS: The Functional Living Index score increased significantly toward the end of the first postoperative year because of an increase in all three factors of the scale. All modes of soft tissue reconstruction achieved nearly equal levels of life quality in patients with median or lateral defects at the end of the observation period. Only patients with large bilateral defects exhibited lower preoperative and postoperative values because of extensive loss of functionally important soft tissue. Patients with discontinuity resections of the mandible took longer to regain the same level of life quality as patients without bone resections. Persistence of dysphagia, reflux of liquids, limitations to liquid food, and sleep disorders had a significant negative effect on the score. CONCLUSIONS: It is concluded that rehabilitation of oral cancer patients is particularly difficult in the case of large soft tissue defects and is not always accomplished completely even with primary microsurgical tissue repair.

Activities of Daily Living↗