Measurement of oxygen partial pressure in the mandibular bone using a polarographic fine needle probe.

In this study, the oxygen partial pressure in the cancellous bone substance of the mandible was measured for the first time with a polarographic fine needle probe. This has so far only been established in soft tissue. The aim was to prove and to test the feasibility in principle of this method of measurement in order to ascertain the normal values for the O2 partial pressure in healthy bone. These values were afterwards compared with the results of measurements in areas of different pathological bone conditions in order to assess the clinical suitability of the method for "mapping" during mandibular resection. Measurements of oxygen partial pressure were made in a total of 42 patients (16 women, 26 men). Of these, 12 patients with clinically normal bones served as a control group. Seventeen patients had osteoradionecrosis following radiation treatment, and 13 patients presented with chronic osteomyelitis of the mandible. All measurements were carried out with a polarographic fine needle probe applied to the cancellous bone substance. The statistical analysis included a comparison of the mean values of the oxygen partial pressures measured. No statistical correlation between oxygen partial pressure and pH and hemoglobin values could be detected. The average oxygen partial pressure in the healthy mandibular bone was 71.4 mmHg. In non-healthy bone, the value fell to an average of 30.6 mmHg (osteoradionecrosis 32.3 mmHg, chronic osteomyelitis of the mandibular bone 28.4 mmHg). Statistically, the differences in the group values ascertained were highly significant (P < 0.005). The data found show that this method can be successfully used to detect poorly perfused bone. The values are reproducible and reflect the clinical situation. In the long term, the method appears to be a suitable diagnostic tool for assessing the oxygen supply in bone in studying various clinical problems related to bone surgery.

[The FAMI screw for temporary intermaxillary fixation. Report of experiences for extending indications]. / Die FAMI-Schraube für die temporäre intermaxillare Fixation. Erfahrungsbericht zur Indikationserweiterung.

The aim of this study was to demonstrate the suitability of the FAMI screw (fixation and adaptation in mandibular injuries) for maxillomandibular fixation in the maxillofacial area in orthognathic and trauma surgery. This FAMI screw was used in 28 patients for maxillomandibular fixation with wiring or elastics. The screw is inserted into the labial or buccal surfaces of the alveolar process without predrilling. Adequate intermaxillary fixation with balanced occlusion was created intraoperatively in all patients. In comparison with conventional splinting methods, this technique was far less time-consuming. The use of the FAMI screw has the advantage of being quick and simple, particularly if only a brief period of maxillomandibular immobilization is planned. Furthermore, the risk to the surgeon of sustaining a puncture injury from wire ligatures is distinctly reduced. Screws can be removed without local anesthesia. The above-mentioned method is minimally traumatic, effective, timesaving, and hence inexpensive. It can be used for maxillomandibular immobilization in dentate as well as in edentulous patients.