Biomedical subjects
Publications and source records attributed to J J Brouns.
The results are reported on six patients who underwent a modified quadrangular osteotomy to avoid dysaesthesia of the infraorbital nerve. The suggested modification served its purpose well, while the functional and aesthetic results were excellent.
The 1 to 8 years follow-up results on a group of 15 patients who underwent a Le Fort I osteotomy with interposed bone grafts and who received implants at a second stage, are reported. The procedure proved to be extremely reliable in that sufficient bone was present for maximum size implants, whilst implant survival appeared to be high (94.6%). The forward advancement was stable and no discernible relapse occurred after prosthesis placement. All patients but one were highly satisfied with the aesthetic result and the rehabilitation of function.
The data of 2049 patients, who underwent maxillofacial orthopaedic surgery, were retrospectively analysed for major intra- and immediate postoperative complications. Immediate life-threatening complications were very rare. They can in most cases be avoided by good anaesthetic and surgical techniques and adequate postoperative care. The most frequently encountered problem in maxillary surgery is excessive blood loss, whilst a compromised airway due to swelling is the most frequent complication in mandibular surgery. Good co-operation between anaesthetist and surgeon is essential to prevent major intraoperative and immediate postoperative problems.
In the Rhine-delta, accumulation of microcontaminants in floodplain foodwebs has received little attention in comparison with aquatic communities. To investigate organochlorine and metal concentrations in a terrestrial foodchain, samples of soil, earthworms (Lumbricus rubellus), and shrew (Crocidura russula, Sorex araneus) livers and kidneys were taken from two moderately to heavily polluted floodplains. Chlorobiphenyl residues in earthworm fat were 0.10 to 3.5 times the concentrations in soil organic matter, whereas ratios for other organochlorines varied between 0.87 and 8.8. These ratios are one order of magnitude lower than expected from laboratory experiments with earthworms, and laboratory and field studies on aquatic invertebrates. Bioconcentration ratios for heavy metals are in accordance with literature values for other locations, confirming the high potential for cadmium accumulation in Lumbricidae. Concentrations of organochlorines in shrew liver lipids were 1.0 to 13 times the residues in earthworm fat. These values are higher than lipid-corrected biomagnification ratios for laboratory rodents, but equal to those measured for benthivorous birds in the Rhine-delta. On a dry weight basis, kidney-earthworm ratios for cadmium were about one order of magnitude lower than previously reported values for insectivores. Soil concentrations of many compounds in both floodplains did not meet Dutch quality standards. Yet, hexachlorobenzene, chlorobiphenyl 153 (PCB153), gamma-hexachlorocyclohexane, sigma DDT, and dieldrin residues in earthworms and shrews did not exceed diet levels expected to be safe for endothermic species. An exception was noted for cadmium in worms and shrew kidneys. Heavy metal pollution in soil was close to levels that are critical to earthworms in laboratory studies. Cadmium concentrations in shrew kidneys were below levels suggested to be safe for Sorex araneus, but above those that were critical to the rat.
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Skeletal stability, temporomandibular joint (TMJ)-function, and inferior alveolar nerve function were evaluated in 103 patients with mandibular hypoplasia who were treated with bilateral sagittal split osteotomies to advance the mandible. Stable internal fixation was obtained with miniplates and four monocortical screws. The follow-up period was at least 24 months (average: 32 months; maximum: 60 months). The average B-point advancement was 5.85 mm. Ninety-three patients of 103 (90.3%) had no appreciable relapse at B-point. Eight (7.7%) patients had relapse because of condylar resorption. Maximum mouth opening decreased an average of 1 mm. Sixty-eight percent of the patients with preoperative TMJ-dysfunction symptoms reported improvement or resolution of their symptoms. Sixteen percent experienced worsening of their TMJ symptoms. Permanent neurosensory deficits were identified in five patients (five sides).
The medium-term results of 12 patients that underwent reconstruction of the severely resorbed maxilla are reported. The method described entails a two-step procedure including Le Fort I osteotomy and grafting of the floor of the sinus and nose with particulate bone and hydroxyapatite (HA). The implants were placed in a second procedure. A 5% failure rate was noted in those patients that were grafted with particulate bone mixed with HA.
The results of a follow-up study of 17 patients who underwent a quadrangular osteotomy, are presented. The indication for a quadrangular osteotomy includes a hypoplastic maxilla with retruded infra-orbital rims and infra-orbital area, but with normal nose projection. Almost all patients were satisfied with the result. Relapse in a horizontal direction appeared to be approximately 12%; however, considerable relapse was seen in the vertical direction (61.7%-158%). A major problem during operation appeared to be the high rate of fractures of the infra-orbital wing. Sensory loss in the area of the infra-orbital nerve occurred in 79% of the operated sides. Four patients needed surgical correction of conditions that should be considered complications resulting from the osteotomy, including a case of partial ischaemic necrosis of the premaxilla in a BCLP patient.
Nineteen patients underwent Le Fort I osteotomy and inferior maxillary repositioning. Miniplates were used to maintain the maxilla in its new position. The patients were followed from 12 to 58 months, postoperatively. Fourteen patients were considered to be stable over the long term. Five patients had a long-term relapse of more than 30%. A tendency towards greater relapse was seen in patients with more than 5 mm inferior repositioning, and in patients who had concurrent segmental osteotomies of the maxilla. In spite of the use of miniplates, there continues to be an element of unpredictability with regard to vertical relapse after inferior maxillary repositioning, and this may be related to soft-tissue influences.
The cutaneous sensibility of 13 pectoralis major cutaneous island flaps has been investigated retrospectively. Although in raising the pectoralis major myocutaneous island flap sensory denervation of the skin is produced, after a mean follow-up period of 29 months (range 5 to 71 months), 68% of the cutaneous portion of the flap revealed sensibility to touch, suggesting a reinnervation from the surrounding intact oral mucosa or skin. The rate of reinnervation was found to be related to the sensibility present in the surrounding tissue.
An in vitro experiment proved that a sialolith can be disintegrated, but that also serious damage is caused to the teeth and dental restorations. Therefore, no experiment was carried out on a patient, although it proved to be possible to position a patient on a lithothriptor in a way that the shock wave of the apparatus would hit the sialolith without passing the brain, eyeballs and laryngeal skeleton.
In a study of 213 patients with oral cancer, we investigated the incidence and prognosis of lung malignancies in patients offered a yearly chest radiography in the follow-up. Three conclusions can be drawn. (1) Metastatic or primary lung cancer was diagnosed in 22 (10.3%) patients. The 2-year actuarial incidence rate of lung cancer following cancer of the oral cavity is 13%. No new lung cancers were detected after 2 years follow-up. This suggests that after this period, yearly chest radiography may be superfluous for the early detection of lung cancer. (2) The survival rate of patients with a lung malignancy following cancer of the oral cavity is poor (1-year = 25%). The survival rate of patients detected by the yearly chest radiography without symptoms is higher than for patients detected after symptoms (p = 0.006). It is not clear to what extent this different survival rate is biased by lead-time and selection of patients with a favourable prognosis. A randomized study would be required to assess whether patients with oral cancer do benefit from the yearly chest radiography compared with no regular chest radiography. (3) Of 22 patients with lung cancer, 13 (59%) were detected by chest radiography without symptoms. In the first year following oral cancer, 11 patients were diagnosed with lung cancer. Only 4 of these 11 patients (36%) were detected by chest radiography in an asymptomatic stage. The detection of patients with lung cancer in an asymptomatic stage may be increased by more frequent chest radiography examinations in the 1st year following oral cancer.
The feasibility of removal of salivary calculi with the aid of high energy shock waves was investigated. The postulation was, that salivary stones can be fragmented and no harm will be done to the surrounding tissues. An in vitro experiment was done with a lithotriptor to test the effect on a salivary stone and an extracted upper molar containing an amalgam restoration. Also investigated was whether a patient can be positioned in a prone position on the lithotriptor. In the in vitro experiment, the salivary stone was fragmented very quickly, but the amalgam restoration also fragmented. The patient could be positioned in the correct position on the lithotriptor, but because of the expected damage to the dentition, the experiment was not carried out on the patient.
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