[Dissertations 25 years after date 46. Treatment of mandibular fractures]. / Proefschriften 25 jaar na dato 46. Behandeling van mandibulafracturen.

In the 1980s, professionals wanted to determine what the best method was for treating fractures of the mandibula. The emergence of osteosynthesis plates in the late 1960s, bringing with them the possibility of immediate functional restoration, had had a dramatic effect. This type of plate was most often placed by means of an extra-oral incision. A decade later, a system of smaller plates was introduced, which were placed intra-orally. A doctoral research project from 1991 investigated the advantages and disadvantages of the various methods of treating a mandibular fracture in order to determine which was most applicable. The importance of careful assessment on the basis of the type of fracture and the desired firmness of the osteosynthesis, described in the dissertation, is still decisive in conclusions concerning surgical treatment method and choice of material.

[Cranio-maxillofacial traumatology]. / Traumatologie van het aangezicht.

During the last 50 years, significant developments have taken place in the treatment of cranio-maxillofacial fractures. The aim of treatment is to achieve the most complete possible restoration of facial functions Epidemiologic figures for these fractures are sparsely available in the literature, but traffic accidents, acts of violence and sports injuries appear to be the main causes. Currently, treatment of facial trauma is aimed at early and (nearly) complete restoration of function. To achieve this goal almost exclusive use is made of stable osteosynthesis methods in The Netherlands. An optimal fixation method exists for nearly every cranio-maxillofacial trauma due to the availability of a large variety of osteosynthesis materials, from micro-plates to reconstruction plates.

A randomized prospective controlled trial of antibiotic prophylaxis in intraoral bone-grafting procedures: preoperative single-dose penicillin versus preoperative single-dose clindamycin.

In this comparative study, 150 consecutive patients undergoing local intraoral bone grafting randomly received either an oral single dose of 600 mg clindamycin or 2 g of the penicillin phenethicillin 1 h before incision. Primary endpoint was wound infection at the receptor site within 8 weeks of surgery. Secondary outcome measurements included postoperative infections at the donor site and adverse events as a result of antibiotic administration. Mean age of the patients was 36.8+/-12.7 years (range 18-67 years), and 98 patients were females (65.3%) and 52 males (34.7%). Infections at the receptor site were seen in 4 patients (5.3%; 95% CI 0.23-10.4%) of the phenethicillin group and in 2 patients (2.7%; 95% CI 0-6.36%) of the clindamycin group. In both groups, 3 patients had an infection at the donor site. Postoperative infections were predominantly caused by alpha-haemolytic Streptococci sensitive to penicillin. No significant difference was found between prophylactic single doses of phenethicillin and clindamycin with regard to postoperative infection in patients undergoing local bone augmentation procedures.

Modeling a fibula transplant in mandibular reconstructions: evaluation of the effects of a minimal number of osteotomies on the contour of the jaw.

The fibula osteocutaneous free flap has become the preferred method for most cases of mandibular reconstruction after oncologic surgical ablation. To recreate the parabolic form of the mandible, the fibula has to be divided up into segments using a closed wedge osteotomy technique. The number of osteotomies is preferably kept to a minimum so that segmental periosteal circulation is not compromised and also to keep operating time to a minimum. The limited number of osteotomies creates an angular contour. The aim of this study was to establish the degree to which overcorrection or undercorrection would occur when a subtotal reconstruction from ramus to ramus was simulated using five bony segments and four osteotomies. The study was carried out using 30 preserved jaws; the contour lines of the jaws were transferred onto tracing paper using a cardboard template. The contour of the mandible was divided into five sections (ramus, body, symphysis, body, and ramus). Because of the cutting off of the curvature in the original jaw outline, the lateral side of the body will become narrower and the chin broader. This also results in an underprojection (displacement) of the chin. To follow the original contour of the jaw as accurately as possible, all these anomalies must be minimized. The amount of under- and overprojection is calculated for a displacement of 1.0, 1.5, 2.5, 5.0, 7.5, and 10 mm of the chin. The most accurate reconstruction of the mandibular contour is achieved with a displacement of 1.5 or 2.5 mm. To preserve sufficient periosteal circulation, the minimum width of bone segments must be 15 mm or more. This concerns especially the symphysis section. On the basis of a fibula thickness of 14 mm, the internal bone width of the symphysis section is calculated. With a displacement of 1.5 mm, the average internal width of the bone segment is 14.8 mm, with a range of 9.9 to 23.0 mm (95 percent confidence interval, 12.8 to 16.7 mm). Therefore, a displacement of 2.5 mm with an internal bone width of 16.4 mm is preferred (range, 11.9 to 24.8 mm; 95 percent confidence interval, 15.5 to 18.2 mm). The loss of lateral projection is minimal (5.8 mm) and the resulting chin width is acceptable (average, 35.0 mm). In conclusion, we propose that in a subtotal procedure, an acceptable jaw reconstruction can be achieved with a limited number of osteotomies. The bone length of the symphysis section remains within safe limits. If the defect is of limited dimensions, then the resulting jaw contour is even more accurate.

[Hyperparathyroidism with maxillo-mandibular deformation]. / Hyperparathyreoïdie met maxillomandibulaire misvorming.

Hyperparathyroidism is a condition due to an elevated secretion of parathormone. Oral manifestations are caused by the disturbance of the calcium-phosphate equilibrium which results in pathologic changes of the bones. A patient with secondary hyperparathyroidism and severe maxillary and mandibular deformations is described.

Fixation methods in mandibular reconstruction using fibula grafts: a comparative study into the relative strength of three different types of osteosynthesis.

BACKGROUND: Bone staples made of a nickel titanium alloy exert dynamic compression, require little dissection, and may provide an alternative to conventional fixation in mandibular reconstruction with a free vascularized fibula graft. METHODS: To evaluate its stability relative to conventional methods of fixation with interosseous wires or miniplates, an in vitro model using beech dowels was developed. Torsional stiffness and strength and compression stiffness and strength were examined. RESULTS: The compression test results showed that maximum strength of interosseous wires is significantly less than memory staples, which in turn are significantly weaker than titanium miniplates. Miniplates are significantly the most rigid form of fixation. Torsional testing showed no significant difference in strength between staples and miniplates and only a marginal difference in elasticity. Interosseous wires show a rapid decrease of strength and rigidity during torsional stress. CONCLUSION: When considering interosseous wires the least and miniplates the most stable form of fixation by which bone healing can occur, memory staples can provide enough stability to ensure consolidation.

Structured assessment of the consequences of composite resection.

A structured quality of life questionnaire was developed as an instrument for the assessment of the functional, physical, psychosocial, and counselling problems in patients treated surgically for an oropharyngeal cancer. The questionnaire was tested in a pilot study in a relatively homogeneous group of 15 selected patients (all of whom had a comparable surgical defect, i.e. a composite resection of the oropharynx and neck, and had undergone an identical reconstruction method, i.e. a pedicled pectoralis major myocutaneous flap). All but two patients were irradiated as well. A high reliability (Crombach's alpha) was found in most of the applied subscales, indicating good internal consistency of the different questions. Significant correlations were found between several quality of life dimensions. The most frequently reported complaints concerned problems related to eating, speaking, and facial disfigurement. Problems with mastication, oral transport, and swallowing prohibited 11 patients returning to their normal diet. Regarding speech, 11 patients reported decreased intelligibility, in eight this was due to some degree of rhinolalia aperta. A significant association was found between moderate intelligibility and anxiety about speaking in public (P < 0.05). Eleven patients felt that the surgery had caused considerable facial disfigurement. For five of them this had a negative influence on their social interactions and activities outdoors. Thus, the consequences of the surgical treatment of oropharyngeal cancer can be assessed in a systematic and formal way with this specially designed structured questionnaire. Despite the small sample size, the selection of a homogeneous patient group appeared to give significant information, and to establish meaningful correlations.

[Mandibular fracture]. / Mandibulafractuur.

This article describes the present status of diagnostic and therapeutic methods to treat mandibular fractures. In view of the needs of a functional rehabilitation as complete as possible, considerations about treatment procedures are presented. Fracture treatment of the mandible in this respect means anatomical reduction and stabilisation of the fracture fragments in order to achieve complete restoration of the bony continuity, preferable without intermaxillary fixation, and restoration of speech and chewing functions enhanced by normal dental hygiene. The role and development of fixation techniques are described and discussed. Finally the role of the general practitioner at the time of diagnostics and initial treatment as well as regarding postoperative treatment and interpretation of treatment modalities is discussed.

The use of miniplates in mandibular fractures. An in vitro study.

To test the stability of miniplate osteosynthesis in the mandible, a three-dimensional in vitro model was developed. Four clinically relevant fracture situations were simulated by osteotomies in polyurethane mandibles. The stability of the osteosyntheses was tested according to a reproducible procedure of unilateral loading under conditions of static equilibrium. The mandible was supported at the condyles in silicon rubber fossae and was held in position by traction on the coronoid processes in combination with preloading in the region of the incisors with a force of 10 N. Six points were tested to register the effects of unilateral loading on bending and torsion at the sites of the osteotomies. The following results were obtained. The preliminary results show that in cases of jaw angle fracture neither bending nor torsional forces are sufficiently controlled by miniplate-fixation in the commonly proposed position. Furthermore, it was confirmed that fracture treatment in the canine region requires two plates instead of one to resist displacement of the fracture fragments during function.

Intra-operative complications in sagittal and vertical ramus osteotomies.

In orthognatic surgery of the mandibular ramus, intra-operative complications as a lesion of the inferior alveolar nerve, fractures of the osteotomised segments, incomplete sectioning, malpositioning of segments and haemorrhage may occur. In this report, intra-operative complications in 124 sagittal split osteotomies and 34 vertical ramus osteotomies, carried out in 80 patients, are described. The incidence of intra-operative complications in the sagittal split osteotomies was 25.8%. The complication occurring most frequently was incomplete sectioning (11.2%). This may be avoided by using the modified sagittal split technique. The incidence of complications in the vertical ramus osteotomies was 11.8%.

Behavior of cortical bone grafts under different types of fixation.

The fate of cortical bone grafts, rigidly fixed by means of a special metal splint, was studied in rabbits. Cortical grafts of fresh autologous bone were compared with dry-stored allogenous transplants frozen to -20 degrees C. To study the incorporation and remodeling, fluorochrome labeling and microradiography were used. The main parameters of remodeling were the quantities of old lamellar bone, newly formed lamellar bone, and vascular spaces present in the transplant areas. The data obtained are compared with the results of a previous similar study of grafts, which were fixed by Mersilene sutures. Fresh autologous as well as allogenous (dry-stored, frozen to -20 degrees C) cortical bone grafts, used as free transplants, show the same type of incorporation and ultimately the same amount of remodeling. Rigid fixation is a valuable contribution in promoting primary function.