Multiple dental implant failures: A retrospective analysis of implant retention time and risk factors

BACKGROUND

The present retrospective study investigates implant retention time in patients who had experienced multiple implant failures and explores possible risk factors.

MATERIALS AND METHODS

Patients who underwent placement of at least two implants and experienced failure of two or more implants between 2004 and 2022 were included in the study population. Both patient- and implant-related risk factors, including age, sex, medical history, medication intake, smoking, alcohol consumption, implant properties and anatomical and surgical factors, were evaluated. Descriptive analysis and univariate and multivariate statistical analysis were performed to assess implant retention time and failure risk, with the level of statistical significance set at 0.05.

RESULTS

A total of 371 patients (178 men and 193 women, median age 63 years) with 3,141 implants were included in the analysis (3.14% of all patients treated since 2004). Out of these implants, 1,090 failures were observed (59.01% of all failed implants at the Academy of Oral Implantology, Vienna, Austria), with a median retention time of 108.11 months. Patients who lost teeth due to periodontitis did not show a tendency towards early implant failure (P > 0.001). Nicotine consumption (P < 0.001), age < 50 years and > 70 years (P < 0.001), maxillary location (P = 0.05), transgingival healing (P < 0.001), no provisional restoration (P = 0.035) and short implant length (P < 0.001) were associated with statistically significantly shorter implant retention times.

CONCLUSIONS

Patients with multiple implant failures displayed cluster behaviour and had a median implant retention time of 9 years. Smoking, short implant length, single-stage surgery and immediate loading were all associated with a higher risk of failure, whereas age between 50 and 70 years and tooth loss due to periodontitis were associated with a longer implant retention time.

Extra-short (< 7 mm) and extra-narrow diameter (< 3.5 mm) implants: a meta-analytic literature review

AIM

To review available evidence in scientific literature on oral implants of severely reduced length or diameter.

MATERIALS AND METHODS

Electronic and hand searches up to May 2017 were performed in order to identify clinical investigations providing implant survival and/or marginal bone resorption data for extra-short implants < 7.0 mm in length and extra-narrow implants < 3.5 mm in diameter (excluding one-piece mini-implants).

RESULTS

A total of 2929 extra-short implants and 3048 extra-narrow diameter implants were investigated in 53 and 29 clinical studies, respectively. Shorter implants between 4.0 mm and 5.4 mm in length showed comparable results to implant lengths of 5.5 mm to 6.5 mm (95.1% vs. 96.4%, P = 0.121) and no difference regarding marginal bone resorption (0.7 mm vs 0.5 mm, P = 0.086). Implant lengths of 5.5 mm to 6.5 mm, however, performed significantly better in the mandible compared with the maxilla (P = 0.010). Smaller diameters between 3.0 mm and 3.25 mm yielded a significantly lower survival rate of 94.3% than wider implants of 3.3 mm to 3.4 mm diameter (97.7%, P < 0.001), while marginal bone resorption did not differ (0.4 mm vs 0.5 mm, P = 0.447).

CONCLUSIONS

The results of the present literature review suggest that extra-short and extra-narrow-diameter implants show satisfactory survival rates of around 95% and little marginal bone resorption of around 0.5 mm after a mean follow-up of 3 years. However, implant lengths < 7 mm in the maxilla and < 5.5 mm in the mandible as well as diameters < 3.3 mm may increase early failure rates.

Effect of dental implants on bisphosphonate-related osteonecrosis of the jaws

PURPOSE

Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is a side effect of BP therapy. Dental implants are believed to be a risk factor for developing BRONJ. In the present study, we analyzed the interval to the development of BRONJ in patients treated with BP who had received dental implants.

PATIENTS AND METHODS

Patients with dental implants and established BRONJ were evaluated at the oral and maxillofacial surgery department (Medical University of Vienna). In addition, studies from 1978 to 2012 were included in a meta-analysis. Three groups were created: implantation before BP treatment, implantation after BP treatment, and implantation during BP treatment. The outcomes were evaluated using linear regression analysis.

RESULTS

Patients who underwent dental implantation during (P < .001) and after (P < .001) treatment with BPs developed BRONJ more rapidly. The treatment duration with oral BPs was significantly related to the rapidity of developing BRONJ (P = .03).

CONCLUSIONS

The insertion of dental implants during or after BP treatment accelerated the development of BRONJ. BRONJ occurred less frequently when the implants had been inserted before BP therapy had been started.

Bone morphogenetic proteins 2, 5, and 6 in combination stimulate osteoblasts but not osteoclasts in vitro

Bone regeneration is required for fracture healing. Various procedures have been used to promote osteogenesis with bone morphogenetic proteins (BMPs). We assessed the effects of BMP-2, BMP-5, and BMP-6 in isolated and combined use on the generation of osteoblasts and osteoclasts by comparing the osteoclastic potency of each on osteoclasts of primary murine bone marrow cells. Subsequently, cells were stained for tartrate-resistant acid phosphatase, and real time PCR analysis of receptor activator of NKκB ligand and osteoprotegerin was conducted. The same combination of BMPs was used to assess their potential to enhance osteoblasts, employing a mineralization assay and real-time PCR analysis of collagen type-1, runx2, and osterix. While BMP-2 alone and the combination of BMP-2 and BMP-5 significantly enhanced osteoclastogenesis, BMP-2, BMP-5, and BMP-6 in combination did not have additional effects. However, the combined use of BMP-2, BMP-5, and BMP-6 had an additive effect on matrix mineralization and osterix expression in osteoblasts. Our study shows that the combination of BMP-2, BMP-5, and BMP-6 stimulates osteoblasts but not osteoclastogenesis. Thus, the synergistic use of various BMPs might improve effective bone regeneration in the clinical setting.

Preoperative chemoradiotherapy in the management of oral cancer: a review

INTRODUCTION

Multi-modality treatment concepts involving preoperative radiotherapy (RT) or chemoradiotherapy (CRT) and subsequent radical resection are used much less frequently than postoperative treatment for oral and oropharyngeal squamous cell carcinomas. In some centres, however, the preoperative approach has been established for several years.

MATERIAL

The present review is a compilation of the existing evidence on this subject.

METHODS

In a literature-based meta-analysis, the survival data of 1927 patients from 32 eligible publications were analysed.

RESULTS

The calculated survival rates of documented patients show remarkably good results with preoperative CRT and radical surgery. However, the findings of this analysis are based on data with a large proportion of studies using consecutive patient series.

CONCLUSION

Hard evidence providing sufficient data from prospective randomised studies is as yet missing for preoperative CRT. Prospective randomised studies are mandatory in this area.

Femoral nerve palsy after mandibular reconstruction with microvascular iliac flap: a complication under anticoagulation therapy

Pharmacological prophylaxis and intervention are used extensively in head and neck reconstructions with microvascular flaps. There is no universally accepted protocol, but the microvascular surgery literature recommends intraoperative anticoagulation with heparin. Here is reported a case of iliacus haematoma with subsequent femoral nerve palsy after the harvest of a microvascular iliac flap for mandibular reconstruction in a patient who had been treated with heparin. The association between femoral nerve palsy and anticoagulant therapy has been well described. It remains unclear as to why the iliacus muscle is particularly vulnerable to intramuscular haemorrhage. Femoral nerve neuropathy is also an uncommon but recognized complication after abdominopelvic surgery. Iliacus haematoma secondary to microvascular surgery has not been previously reported. This case illustrates the need to be aware of this type of complication and its clinical manifestations for patients under anticoagulant therapy in the perioperative period during microvascular reconstructions.

Mortality and Causes of Death After Multimodality Treatment for Advanced Oral and Oropharyngeal Cancer

PURPOSE

To analyze mortality and causes of death in patients who received preoperative radiochemotherapy and underwent radical surgery for advanced oral or oropharyngeal cancer.

PATIENTS AND METHODS

A total of 222 patients who underwent multimodality treatment from 1990 to 2000 were included in the study. The inclusion criterion was International Union Against Cancer (UICC) disease stage II to IV (T2, 33.3%; T3, 12.6%; T4, 54.1%). Patients received preoperative radiotherapy 50 Gy and concomitant chemotherapy with mitomycin and 5-fluorouracil. Radical local-regional en bloc resection was performed in all patients. Survival status and causes of death were ascertained from the National Health Registry. Death certificates and autopsy reports were consulted when hospital files failed to provide reliable data.

RESULTS

After a median surveillance period of 72.3 months (range, 24 to 152 months), 59% of patients were alive, 21% had died of recurrence, 5% had died perioperatively, and 15% had died from other causes. Of these, a second cancer in the head and neck region or the lower respiratory tract or the upper digestive tract was found in 7.3%. Although 93% of deaths related to recurrent disease occurred within the first 36 months after surgery, the remaining causes of death did not reveal a specific temporal pattern.

CONCLUSION

Favorable survival data were registered for patients with advanced squamous cell carcinoma of the oral cavity who underwent combined treatment protocols. These patients frequently die of comorbidities. Because recurrent disease is a less common cause of mortality than are other causes, the latter should receive attention during surveillance.

Influence of Previous Radiotherapy on Free Tissue Transfer in the Head and Neck Region: Evaluation of 455 Cases

OBJECTIVE/HYPOTHESIS

The aim of this retrospective cohort study was to investigate the effect of prior radiotherapy (XRT) on the outcome of microvascular free tissue transfer in the head and neck region.

METHODS

Four hundred fifty-five patients, subdivided into three groups, were analyzed. Groups I (no previous XRT, n=110), II (previous radiochemotherapy with 50 Gy focus dosage in the primary treatment regime for oral cancer, n=322), and III (secondary reconstruction after XRT-induced complications, n=23) were compared regarding flap success rate, postoperative complications, postoperative mortality, duration of intensive care (DOIC), and hospitalization (DOH).

RESULTS

Flap success did not differ significantly across groups (I: 95.5%, II: 93.2%, III: 91.3%. Risk of postoperative complications was significantly lower for group I (12.7%) compared with groups II (23.9%) and III (39.1%). DOIC and DOH were significantly shorter for patients in group I than for those in groups II and III.

CONCLUSIONS

XRT before free tissue transfer does not significantly increase flap loss or postoperative mortality but does increase postoperative complications and length of hospitalization.

Experience with microvascular free flaps in preoperatively irradiated tissue of the oral cavity and oropharynx in 303 patients

This study examined free flap reconstruction of surgical defects of the oral cavity and oropharynx after preoperative radiochemotherapy. Included in this analysis are 303 prospectively followed patients who underwent a multimodal treatment regime for advanced oral and oropharyngeal carcinoma. All patients received preoperative radiochemotherapy (Mitomycin C, 5-FU, 50 Gy), ablative surgery, and primary free flap reconstruction. Patient characteristics, surgical parameters like duration of surgery and ischaemia, size of defect, type of transplant, and clinical outcome parameters like duration of intensive care and hospitalization, type of complications, necessity and type of revision surgery were statistically evaluated. Overall flap success rate was 93.1%. Sixty seven patients required revision and 21 flaps (6.9%) were lost. Overall complication rate was 22.1%. Mean duration of intensive care (DOIC) and duration of overall postoperative hospitalization (DOH) were 11.0+/-9.6 days and 35.9+/-26.3 days, respectively. Flap success and flap related complications after 50 Gy focal radiation dosage were found in a comparable range as in published series of reconstructions in uncompromised tissue.

Preoperative radiochemotherapy and radical resection for stages II to IV oral and oropharyngeal cancer: grade of regression as crucial prognostic factor

The purpose of this study was to assess the prognostic value of histological response to preoperative radiochemotherapy in an established multimodal therapy concept for advanced oral and oropharyngeal cancer. Two hundred and twenty-two patients who underwent preoperative radiochemotherapy (RCT: 50 Gy, mitomycin C and fluorouracil) and radical surgery were retrospectively evaluated. Resected tumours of all patients were histologically analysed and response to RCT was classified in histopathological grades of regression (RG). In a multivariate statistical analysis, RG was compared with established factors regarding their predictive value for overall and disease-specific survival. The 5-year overall survival probability in the different groups of histopathological regression grades were: RG1 (no vital tumour): 73.4%, RG2 (minimal tumour remnants encompassing less than 5%): 72.1%, RG3 (5-50% vital tumour cells): 41.9%, RG4 (more than 50% vital tumour): 37.9%. For disease-specific survival probability no significant differences were found between both groups of "responders" (RG1 and RG2) nor between "non-responders" (RG3 and RG4), whereas responders and non-responders differed significantly from each other (log-rank test; p < 0.001). T-classification, N-classification and disease stage, histological grading, tumour site, age, and sex had less prognostic value than RG in a Cox regression model. In the neoadjuvant multimodal therapy concept, histological response to preoperative RCT is a crucial prognostic factor even when surgical R0-resection is accomplished. Thus, non-responders have to be regarded as high-risk patients for recurrence and may benefit from further therapy.

Preoperative radiochemotherapy and radical resection for stages II–IV oral and oropharyngeal cancer: outcome of 222 patients

To analyse survival and locoregional control in patients with advanced oral and oropharyngeal squamous cell carcinoma (SCC) after multimodal therapy with preoperative radiochemotherapy (RCT) and radical surgery. We included in this analysis 222 patients who underwent multimodal therapy between 1990 and 2000. Eligible were patients with UICC disease stages II-IV (T2: 33.3%; T3: 12.6%; T4: 54.1%; N0: 45.9%; N1: 17.6%; N2: 33.3%; N3: 3.2%; stage II: 21.1%; stage III: 14.9%; stage IV: 64%). Patients received preoperative radiochemotherapy consisting of Mitomycin C (15-20 mg/m2, day 1) plus 5-Fluorouracil (750 mg/m2/24 h-infusion, days 1-5) and concomitant radiotherapy for a total dose of 50 Gy. Radical locoregional en bloc-resection according to the pretherapeutic tumour extension was carried out in all patients. After a median surveillance period of 72.3 months (24-152 months), 131 patients (59%) were alive, and 91 (41%) patients died; 12 (5%) of them died postoperatively, 46 (21%) due to tumour recurrence, and 33 (15%) deaths were not directly related to the primary tumour. Overall survival probability was 76% after 2 years, and 62% after 5 years. Two- and 5-year local control probability were 88 and 81%, respectively. Regarding the high percentage of stage IV disease in the reported patients, the multimodal concept is an effective therapy offering excellent survival and local control probability.

Neoadjuvant radiochemotherapy of oral cavity and oropharyngeal cancer: evaluation of tumor response by CT differs from histopathologic response assessment in a significant fraction of patients

BACKGROUND

Our aim was to compare and assess the predictive value of CT and histopathologic grading of tumor regression at primary tumor sites in patients with squamous cell carcinoma of the oral cavity and oropharynx after neoadjuvant (preoperative) radiochemotherapy (RCT).

METHODS

We investigated 55 patients with carcinomas of the oral cavity and oropharynx who underwent RCT before curative surgery. Two blinded observers measured RCT-induced reduction of tumor volume in pretherapeutic and posttherapeutic CT scans. Volume changes were compared with histopathologic findings obtained at surgery.

RESULTS

Histopathologic response evaluation revealed 31 complete remissions, 12 cases of partial response, and 12 nonresponders. We performed a logistic regression analysis to evaluate whether measured volume reduction could predict the likelihood of belonging to a certain response group. Taken together, we found 35 correct, 12 false-negative, and seven false-positive predictions.

CONCLUSIONS

The extent of remission as assessed by CT scans 4 to 5 weeks after completion of neoadjuvant RCT leads to false predictions in a significant percentage of patients.

Cross-sectional and functional imaging of the temporomandibular joint: radiology, pathology, and basic biomechanics of the jaw

The temporomandibular joint (TMJ) is a common site of complaint. Clicking sounds and pain are indicators of a frequent condition called internal derangement, most often affecting females. As a general term, internal derangement describes a structural abnormality within an articulation. The internal derangement of the TMJ is a specific term defined as an abnormal positional and functional relationship between the disk and articulating surfaces. Imaging of the joint is an important element in the diagnostic work-up. Trauma and inflammatory arthritis account for most of the other TMJ problems. A thorough understanding of joint anatomy and normal function is a prerequisite for perceiving abnormalities and making the correct diagnosis. The authors elucidate joint anatomy, correlating cadaveric specimen and anatomic slices with conventional and cross-sectional imaging studies. TMJ biomechanics are illustrated with schematics and animations, and an overview of imaging strategies and techniques is presented. Common abnormalities are described and illustrated, and a brief discussion of therapeutic options is included.

Quality of life 2-10 years after combined treatment for advanced oral and oropharyngeal cancer

This study reports the findings of an evaluation of Quality of Life (QOL) in long-term survivors of advanced oral and oropharyngeal cancer treated with preoperative chemoradiotherapy followed by surgery (combined treatment=multimodal therapy). All patients had T2-T4 tumours and all received locoregional radical resection and simultaneous microvascular reconstruction. From 1990 to 1998, 181 patients have been treated at the University Hospital of Cranio-Maxillofacial and Oral Surgery in Vienna. 100 (55%) of these patients were alive and free of disease in 2000. Sixty-seven of them completed the EORTC questionnaires QLQ 30 and QLQ H&N 35. We found these questionnaires to be very good tools for determining QOL, which constitutes part of the therapeutic success. Patients tended to report good to very good QOL. A comparison between groups according to clinical data was conducted as well as a group comparison of patients who claimed especially high or low QOL in the questionnaires. It was found that combined treatment not only offers the best chances for survival, but also allows a subsequent QOL, that is comparable to other forms of therapy.

A comparison of the donor-site morbidity after using the prelaminated fasciomucosal flap and the fasciocutaneous radial forearm flap for intraoral reconstruction

Since 1996 we have performed mucosal prelamination of the distal radial forearm flap for functional reconstruction of defects of the intraoral lining. This study was undertaken to demonstrate that the prelaminated fasciomucosal radial forearm flap can provide physiological oropharyngeal reconstruction with mucus-producing tissue, while avoiding the donor-site complications of the fasciocutaneous radial forearm flap. We examined the donor hand at least 6 months postoperatively in 20 patients after using a prelaminated fasciomucosal radial forearm flap and in 15 patients after harvesting a classical fasciocutaneous radial forearm flap. The evaluation of hand function included range of motion, grip power, pinch power, sensibility and vascular analysis in both hands. The patients were asked about cold intolerance, pain and any restrictions in daily life, and the cosmetic appearance of the donor hand was noted. In the prelaminated-flap group (n 20), two patients had decreased wrist extension, and one of these patients also had reduced strength and mild hypaesthesia in the donor hand. In the classical-fasciocutaneous-flap group (n 15), six patients had decreased wrist extension, five patients had reduced strength and four patients had diminished sensibility in the donor hand. Painful neuromas were found only after fasciocutaneous flaps (three cases). Subjective assessment revealed restricted hand function in one patient in the prelaminated-flap group, and in five patients who had undergone fasciocutaneous flap transfer. The results of this study show that using the prelaminated fasciomucosal radial forearm flap minimises the donor-site morbidity. Furthermore, we were able to improve the cosmetic appearance of this very exposed region.

The influence of deliberate hypotension on splanchnic perfusion balance with use of either isoflurane or esmolol and nitroglycerin

Various techniques to induce deliberate hypotension (DH) have different influences on splanchnic perfusion. The aim of our study was to determine whether splanchnic perfusion is clinically impaired during DH by using either isoflurane (ISO) or a combination of esmolol and nitroglycerin (E/N). We randomized 16 patients undergoing elective maxillofacial surgery to receive either ISO (0.7%-1.8%) or E (105 g x kg(-1) x min(-1)) and N (1-6 mg/h) to induce DH. General anesthesia was performed in both groups by IV midazolam 0.07 mg/kg, fentanyl 0.003 mg/kg, propofol 1.5 mg/kg, and vecuronium 0.1 mg/kg followed by a propofol infusion with 6 mg x kg(-1) x h(-1). After the induction of anesthesia, a gastric tonometer (TRIP NGS Catheter) and a radial artery catheter were inserted. Baseline values of gastric intramucosal pH (pHi) were determined 60 min after placement of the catheter and before the induction of DH. The pHi values were calculated every 60 min until DH was discontinued. In both groups, DH was satisfactorily established. None of the pHi values calculated was less than 7.37 in the E/N or 7.41 in the ISO group. Arterial blood lactate levels did not increase in any of the patients. We conclude that neither method of producing DH compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate.

IMPLICATIONS

Neither the isoflurane nor the esmolol/nitroglycerin method of producing deliberate hypotension compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate.

Preprosthetic vertical distraction osteogenesis of the mandible using an L-shaped osteotomy and titanium membranes for guided bone regeneration

PURPOSE

Vertical osteodistraction is a new alternative method for alveolar ridge augmentation of the mandible. The purpose of this article is describe a technique using an L-shaped osteotomy and titanium membranes for guided bone regeneration (GBR) in the distraction gap.

PATIENTS AND METHODS

Ten patients with severe atrophy of the edentulous molar region of the mandible underwent vertical callus distraction in 13 sites using intraoral microplate distractors. An L-shaped osteotomy with a short vertical part mesially and a longer horizontal part ending in the retromolar region was made, and the osteotomized segment was fixed to the mandibular ramus at its distal edge by a microplate, which became the center of rotation when distraction began. In this way, more callus generation could be achieved mesially than in the distal molar region. Follow-up computed tomography (CT) scans reconstructed axially to the axis of the mandible revealed semilunar excavations of the generated bone buccally in the distraction gap in the first cases. Clinical inspection on removal of the distractors showed fibrous connective tissue in the gap. Therefore, to prevent this from happening, titanium membranes covering the distraction gap were applied in subsequent cases.

RESULTS

Ten patients (13 sites) were treated by vertical callus distraction. In 4 cases, GBR was achieved using titanium membranes. In all cases, the increase in alveolar height was sufficient to make dental implantation possible. In 1 patient, a fracture of the distractor occurred, and dehiscence was observed in 2 cases. These complications did not change the plan of therapy nor did they influence the results. The CT scans showed a homogenous surface on the regenerated mandible in the cases of GBR application.

CONCLUSION

Both an L-shaped osteotomy and the application of titanium membranes for GBR in the distraction gap are of great value for mandibular augmentation, producing a physiologically shaped alveolar ridge.

Muscle-nerve-muscle neurotization of the orbicularis oris muscle

INTRODUCTION

A denervated half of the orbicularis oris muscle is not reinnervated spontaneously by axon sprouting from the intact contralateral side. The borderline between the facial nerve territories seems to act as a barrier. The muscle-nerve-muscle technique was advocated as a technique to reneurotize a denervated half of the orbicularis oris muscle in cases of marginal mandibular paralysis.

MATERIAL AND METHODS

This muscle-nerve-muscle neurotization was tried to induce reinnervation of a denervated angle of the mouth in four patients. Grafts were harvested from the sural nerve. Functional recovery was assessed by measurement of facial movements and by electrophysiological examination.

RESULTS

In three of the four cases presented, this technique helped to improve function of the lower lip. The clinical relevance of the results is discussed.

Impact of hemoglobin level and use of recombinant erythropoietin on efficacy of preoperative chemoradiation therapy for squamous cell carcinoma of the oral cavity and oropharynx

PURPOSE

We assessed the influence of hemoglobin level and r-HuEPO administration on response to chemoradiotherapy, locoregional tumor control, and overall survival in patients treated with neoadjuvant chemoradiotherapy and surgery for a squamous cell carcinoma of the oral cavity or oropharynx.

METHODS AND MATERIALS

The 191 study patients were treated with mitomycin C (15 mg/m(2) day 1), 5-fluorouracil (750 mg/m(2)/day, days 1-5), and radiotherapy (50 Gy in 25 fractions weeks 1-5), followed by resection of the primary tumor bed and neck dissection at the General Hospital Vienna, Austria, between November 1989 and October 1998 for a T2-4, N0-3, M0 SCC of the oral cavity or oropharynx. Starting in May 1996, patients with a low hemoglobin (Hgb) before or during chemoradiotherapy received r-HuEPO 10,000 IU/kg s.c. 3-6 times/week until the week of surgery.

RESULTS

On multivariate analysis, Hgb level and use of r-HuEPO were independent prognostic factors for response to chemoradiotherapy and locoregional tumor control (p < 0.01). Pathologic response to neoadjuvant therapy was also predictive of locoregional control (p < 0.001). Patients with a pretreatment Hgb > or = 14.5 g/dL had significantly higher complete response, locoregional control, and survival rates than the patients with a pretreatment Hgb < 14.5 g/dL who did not receive r-HuEPO (p < 0.05). The response, control, and survival rates in patients with a pretreatment Hgb < 14.5 g/dL given r-HuEPO were significantly higher than in low Hgb patients not given r-HuEPO (p < or = 0.001) and equivalent to patients with a pretreatment Hgb > 14.5 g/dL (p > or = 0.3).

CONCLUSION

Low pretreatment Hgb is a negative prognostic factor for oral cavity and oropharyngeal SCCA patients, but was completely abrogated by r-HuEpo administration during neoadjuvant chemoradiotherapy. Randomized trials of radiation and/or chemotherapy with or without r-HuEPO for patients whose Hgb level is either low at the start of therapy or is anticipated to become low during therapy are indicated.

Immune competent cells in non-irradiated autologous jejunal grafts used for reconstruction of the oral cavity and oropharynx

Autologous jejunal grafts used for primary reconstruction in cases of extensive soft tissue defects following tumor resection in the upper aerodigestive tract were investigated by immunohistochemistry (APAAP technique). Biopsies from eight patients were taken intra-operatively, at the time of transplantation and 2, 4, and 6 months post-operatively. A panel of monoclonal antibodies directed against surface antigens of the major subpopulations of the immune system was used. In all of the patients, a remarkable increase of all antigens investigated was detected 2 months post-operatively, which remained unchanged in the following biopsies (4 and 6 months postoperatively). Significantly higher numbers of CD45RA+ and CD45RO+ (P<0.05) leukocytes were detectable. This increase was due to both subsets of T and B cells, but only for CD19+ B cells was the increase significant. In addition, NK cells (CD16+ lymphocytic cells, P<0.01) and mature macrophages (25F9+ cells, P<0.01) increased. The first post-operative biopsy showed a significantly higher expression of activation-associated antigens (ICAM-1, VCAM, and HLA-DR) on monocytes/macrophages and endothelial cells. Our findings indicate that autologous jejunal grafts facilitate immunological function in the new microenvironment.

Experimental study of muscle-nerve-muscle neurotization

A laboratory model for the study of possible reinnervation by muscle-nerve-muscle (MNM) neurotization is presented. Preliminary studies revealed that MNM neurotization occurs in synergistically closely-related facial muscles. However, for larger antagonistic somatic muscle (flexor and extensor), this phenomenon could not be reproduced. The potential clinical relevance of these findings is presented and discussed.

Multifocal eosinophilic granuloma of the jaw: long-term follow-up of a novel intraosseous corticoid treatment for recalcitrant lesions

Eosinophilic granuloma of the jaws is a rather benign and localized form of Langerhans' cell histiocytosis. Treatment is usually required in larger lesions that cause local pain and swelling and pose the risk of spontaneous fractures. There are several accepted forms of treatment, which include surgery, radiation therapy, systemic and local therapy with corticoids, and systemic chemotherapy. No studies exist that compare the effectiveness of these treatment modalities. We report a novel therapeutic regimen that uses repeated intraosseous injections of triamcinolone-1 16 alpha 21-diacetat, a synthetic corticoid, which led to a rapid, complete, and durable treatment. The patient had a multilocal eosinophilic granuloma of the mandible in which radiation therapy, systemic corticoid therapy, and systemic chemotherapy had failed.

Guided bone regeneration with titanium membranes: a clinical study

Guided bone regeneration using barrier membranes is useful in bone augmentation. Because the commonly used polytetrafluoroethylene (PTFE, Gore-Tex (R), WL Gore, Flagstaff, AZ, USA) membranes or resorbable membranes tend to collapse, more stable membranes are desirable. A titanium membrane (FRIOS(R) BoneShield, Friatec, Mannheim, Germany) was evaluated in a clinical study of 52 patients. Most of them had particulate bone grafts or phycogene hydroxyapatite (Algipore(R), Friatec, Mannheim, Germany) or both stabilized with titanium membranes. In 78 procedures, 23 membranes (29%) became exposed, but only seven of these (9%) led to failure of the graft with a considerable loss of augmented material. The time interval between operation and possibly exposure was responsible for the result. Early exposures (within a few weeks) led to poor formation of new bone within the grafts, whereas if exposure was later, results were as good as in procedures in which the membranes did not become exposed.

The L-shaped osteotomy for vertical callus distraction in the molar region of the mandible: a technical note

The following report refers to a well described surgical procedure using a prototype vertical distractor developed in Cologne in cooperation with Martin Medizintechnik GmbH. The surgical technique has been refined by an L-shaped osteotomy stabilized posteriorly by a miniplate to limit the amount of callus regeneration in the molar region where no increase in vertical height is required. The surgical technique with its advantages and one complication is described as used in four patients undergoing six distraction treatments.

Clinical experience with interactive teleconsultation and teleassistance in craniomaxillofacial surgical procedures

PURPOSE

The objective of this study was to evaluate the clinical value and feasibility of surgical telenavigation and teleassistance technology in the field of craniomaxillofacial surgery.

MATERIALS AND METHODS

The technology is based on the principles of augmented reality environment technology and remote stereotactic visualization. A consultant surgeon in a remote location receives video, audio, and stereotactic navigation data from the operation site almost in real-time and, using a head-mounted display, is emerged in the surgical augmented reality environment. By telepresence or teleconsultation, the composite images and superimposed graphics (instruments, target structures, landmarks, contours) can be seen and discussed in connected clinics with the possibility of interactive manipulation and assistance.

RESULTS

Interactive teleassistance was used in 27 cases of various types craniomaxillofacial surgery. The principles of computer-aided telenavigation were applied successfully. Technical problems in 6 cases did not cause a breakdown of overall system performance.

CONCLUSION

Teleconsultation with remote experts is a useful tool, although some shortcomings exist. The financial and personal effort involved is considerable.