Treatment of mandibular angle fractures using one noncompression miniplate

PURPOSE

This study evaluated the results in patients treated for fractures of the mandibular angle with a single miniplate.

PATIENTS AND METHODS

Eighty-one patients with fractures of the mandibular angle were treated by open reduction and internal fixation using one noncompression miniplate with 2.0-mm self-threading screws placed through a transoral incision. No patient was placed into postsurgical maxillomandibular fixation. They were prospectively studied for complications.

RESULTS

Thirteen patients with angle fractures (16%) experienced complications requiring secondary surgical intervention. Most of the complications (n = 11), however, were minor and could be treated in the office. Most commonly, intraoral incision and drainage and later removal of the bone plate were required. All patients with minor complications had clinical union. Only two complications required hospitalization for intravenous antibiotics and further surgery. One of these patients had a fibrous union requiring a bone graft.

CONCLUSIONS

The use of a single miniplate for fractures of the angle of the mandible is a simple, reliable technique with a relatively small number of major complications.

Circulating factor associated with increased glomerular permeability to albumin in recurrent focal segmental glomerulosclerosis

BACKGROUND

Heavy proteinuria and progressive renal injury recur after transplantation in up to 40 percent of patients with renal failure caused by idiopathic focal segmental glomerulosclerosis. A circulating factor may be responsible for this recurrence.

METHODS

To determine whether patients with focal segmental glomerulosclerosis have a circulating factor capable of causing glomerular injury, we tested serum samples from 100 patients with the disorder in an in vitro assay of glomerular permeability to albumin. Of the 56 patients who had undergone renal transplantation, 33 had recurrences. Sixty-four patients, many of whom had undergone transplantation, were being treated with dialysis. Thirty-one patients with other renal diseases and nine normal subjects were also studied.

RESULTS

The 33 patients with recurrent focal segmental glomerulosclerosis after transplantation had a higher mean (+/-SE) value for permeability to albumin (0.47+/-0.06) than the normal subjects (0.06+/-0.07) or the patients who did not have recurrences (0.14+/-0.06). After plasmapheresis in six patients with recurrences, the permeability was reduced (from 0.79+/-0.06 to 0.10+/-0.05, P = 0.008), and proteinuria was significantly decreased. Patients with corticosteroid-sensitive nephrotic syndrome or with membranous nephropathy after transplantation had low levels of serum activity. The circulating factor bound to protein A and hydrophobic-interaction columns and had an apparent molecular mass of about 50 kd.

CONCLUSIONS

A circulating factor found in some patients with focal segmental glomerulosclerosis is associated with recurrent disease after renal transplantation and may be responsible for initiating the renal injury.

Analysis of treatment for isolated zygomaticomaxillary complex fractures

PURPOSE

The purpose of this study was to evaluate the adequacy of reduction and stability of fixation of isolated zygomaticomaxillary complex (ZMC) fractures treated by various methods over a 5-year period.

PATIENTS AND METHODS

Forty-eight patients with isolated, unilateral ZMC fractures that had at least 6 weeks' clinical follow-up were studied. Demographic information and methods of treatment were obtained from the medical records. Quality of reduction was assessed by examination of postoperative images. Stability of the repositioned ZMC was assessed by comparing immediate postoperative images with those obtained at least 5 weeks later. Cosmetic outcomes were assessed by clinical assessment and examination of photographs.

RESULTS

A variety of surgical approaches and fixation sites were used in the sample. All patients but five had satisfactory reductions performed during surgery. In two of the latter, no noticeable facial deformity was apparent. No patient showed postsurgical change in position of the reduced ZMC. Three patients showed postsurgical enophthalmos at longest follow-up. Approximately 20% of those having lower eyelid incisions had some amount of scleral show at longest follow-up.

CONCLUSIONS

A variety of techniques can be used to produce a satisfactory outcome. Based on the results and a review of the literature, recommendations for treatment are proposed.

The future of oral and maxillofacial surgery in the United States

This paper explores the past, present, and future of the specialty of oral and maxillofacial surgery in the United States as viewed through the eyes of the author. Many changes have occurred over the past ten years that have changed the complexion of the entire health care industry. The overall effect of these changes is to decrease the amount of funding that will be available for our services. These changes have caused challenges for the specialty. How will we cope? Will we survive? Are we relevant? The challenges facing the specialty of oral and maxillofacial surgery as practised in the United States are discussed, and recommendations for change are put forth.

Speech and language in first onset psychosis differences between people with schizophrenia, mania, and controls

BACKGROUND

Several studies have revealed linguistic differences between diagnostic groups. This study investigates the extent to which these differences are accounted for by factors such as chronicity, or disturbances in cognition associated with acute psychosis.

METHOD

Transcripts of interviews with patients suffering from RDC schizophrenia (n=38), mania (n=11) and controls (n=16) were examined using the Brief Syntactic Analysis (BSA). Patients were within two years of first onset of psychotic symptoms, and received tests of working memory and attention.

RESULTS

The speech of patients with schizophrenia was syntactically less complex than that of controls. Patients with schizophrenia and mania made more errors than controls. These differences were, to some extent, related to group differences in social class, working memory and attention, although significant group differences in language persisted after the effects of covariates were removed.

CONCLUSIONS

The study confirms the existence of differences in the speech of psychiatric patients. Low complexity appears to be a particular feature of speech in schizophrenia, even in the earliest stages of the condition. The importance of this finding is discussed in relation to two recent theories of schizophrenia: Crow's evolutionary model, and Frith's neuro-psychological model.

The reliability and characteristics of the brief syntactic analysis

BACKGROUND

Linguistic analysis is of great potential benefit to psychiatry as a research and assessment tool, but the skill and time it demands means that it has not been widely used. This paper describes a much simplified form of syntactic analysis.

METHOD

A detailed protocol for the Brief Syntactic Analysis (BSA) was written, based on earlier work by Morice and Ingram. Three psychiatrists were trained in its use, and inter-rater reliability established through independent ratings of 12 transcripts taken from a mixed group of psychiatric patients and a group of non-psychiatric controls. Concurrent reliability of the BSA against the Morice and Ingram analysis was established by comparing measures from the two methods on 16 transcripts of mixed patients.

RESULTS

There were high levels of agreement between the three psychiatrists and between the BSA and the Morice and Ingram analysis, although one-way ANOVA indicated that for some variables there were small but statistically significant absolute differences between the two. The reasons for this were discussed. A principal components analysis confirmed the presence of three factors corresponding closely to the three families of linguistic variables.

CONCLUSIONS

The results indicate that psychiatrists can be trained to use a syntactic analysis with high levels of agreement. The BSA, which takes much less time to complete, produces measures that are comparable with the original analysis from which it was derived.

Microangiopathic glomerulopathy in children with sickle cell anemia

We studied kidney biopsy specimens from three children with sickle cell anemia and microangiopathic glomerulopathy. One child also had cyanotic congenital heart disease. Laboratory evaluation revealed proteinuria and normal serum creatinine in all and normal serum complement in two of the three children at the time of biopsy. In all biopsies, glomeruli were enlarged with diffuse hypercellularity and focal segmental mesangial interposition; capillary loop lumens were congested with sickled erythrocytes. Immune labeling identified segmental immunoglobulin G, C3, and properdin over the glomerular capillary loop walls in each case. Ultrastructurally, the subendothelial zone of the glomerular basement membrane was widened with new lamina densa formation with focal mesangial interposition. The glomerular lesion we describe in these children may be due to endothelial injury related to the altered erythrocytes, glomerular hemodynamics, and the hypercoagulable state characteristic of sickle cell disease.

Bite forces before and after surgical correction of mandibular prognathism

PURPOSE

The purpose of this investigation was 1) to compare morphologic parameters and voluntary bite forces between controls and a sample of patients with mandibular prognathism before surgical correction, and 2) to examine how these patients' bite forces adapt after treatment.

PATIENTS AND METHODS

Twenty-four prognathic patients were compared with 24 controls before and up to 3 years after mandibular setback surgery. Measures of skeletal morphology and maximum isometric bite force were made on all subjects over time. Statistical analysis compared the controls, the patients before surgery, and the patients after surgery.

RESULTS

Surgical shortening of the mandible averaged 4.1 mm, bringing most skeletal measures into the normal range. Before surgery, the jaw muscle mechanical advantages for patients were significantly smaller than for controls; surgery did not significantly change this relationship. Before surgery the patients had maximum isometric bite forces that were significantly less than those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 to 3 years.

CONCLUSIONS

The results of this study suggest that correction of mandibular prognathism by mandibular setback surgery produces some significant functional benefits.

The effect of nedocromil sodium on childhood asthma during the viral season

Viral-induced symptomatic respiratory infections (SRI) frequently cause exacerbations of asthma in children. This study investigated the protective effects of 0.5% nedocromil sodium nebulizer solution given three times a day in preventing asthma exacerbations associated with SRI. Ninety-three mild-moderate asthmatic children (6 to 12 yr of age) received either 0.5% nedocromil sodium or placebo for 24 wk during the viral season. The nedocromil sodium group was symptom-free 58% of the days, and the placebo-treated patients were symptom-free 45% of the days (p = 0.027). During Weeks 1-12, significant differences favored nedocromil sodium for asthma summary score (means: nedocromil sodium = 0.61, placebo = 0.92; p = 0.026), and daytime asthma (nedocromil sodium = 0.78, placebo = 1.22; p = 0.03). Significant differences were noted during monthly intervals for cough (Weeks 1-4: nedocromil sodium = 0.61, placebo = 0.92, p = 0.027) and peak expiratory flow rate (PEFR) (nedocromil sodium 262, placebo = 254 L/min, p = 0.041 Weeks 9-12). Patients in the active treatment group reduced their need for rescue inhaled beta 2-agonist by 10%, whereas patients treated with placebo demonstrated a 24% increase. There was a strong correlation between asthma symptoms and SRI symptoms (r = 0.47; p < 0.001). During SRIs, patients in the nedocromil sodium group demonstrated more rapid resolution of asthma symptoms immediately following infection (p = 0.033 summary score, p = 0.039 sleep difficulty). No serious adverse events were noted. Nedocromil sodium did not prevent the infection or exacerbation of asthma symptoms during SRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional and morphologic alterations secondary to superior repositioning of the maxilla

PURPOSE

The purpose of this investigation was to 1) compare morphological characteristics and functional performance of a sample of patients with vertical maxillary excess (VME) with controls, and to 2) examine how the patients' oral motor function adapts to surgery.

MATERIALS AND METHODS

Fifteen female VME patients were compared with 26 female controls before and up to 3 years after maxillary intrusion surgery. Measures of skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyogram (EMG) activity in some of the muscles of mastication were made on all subjects over time. One-way analysis of variance (ANOVA) was used to compare the controls with the patients before and after surgery. Univariate repeated measures ANOVA was used to study longitudinal changes in the patients.

RESULTS

Preoperatively, the patients possessed morphological measurements characteristic of vertical maxillary excess. Superior repositioning of the maxilla averaged 3.3 mm. Concurrently, most skeletal measures were brought closer to normal values. Masseter muscle mechanical advantage was significantly lower in the patients than in controls both before and after surgery (P < or = .05). There was no significant difference between patients and controls for other biomechanical measurements. Mandibular hypomobility was apparent at 6 weeks after surgery, but returned to control values within 6 to 12 months. Before surgery, the patients had maximum isometric bite forces significantly less than those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 years. Before surgery the patients' muscle activity levels per unit of bite forces were equivalent to those of controls or somewhat lower. After surgery some of the patients' muscles had significantly lower levels of muscle activity per unit of bite force than did controls.

CONCLUSIONS

The results of this study suggest that correction of vertical maxillary excess with maxillary intrusion surgery improves some characteristic functional deficits.

Structural properties of mandibular bone following application of a bone plate

PURPOSE

Similarities in strain patterns between long bones and the mandible suggest that plates may induce stress shielding, resulting in deleterious long-term changes. This study is an investigation of the use of bone plates on the mandible in four adult rhesus monkeys.

MATERIAL AND METHODS

A stainless steel plate was attached facially along the inferior border of each mandibular corpus. On the left, a thick (2.5-mm) plate was engaged with four screws. On the right, a thin (0.5-mm) plate was attached with one screw. Monkeys were killed a year after plate placement. At the beginning and end of the experiments, bone strain was recorded inferior to each bone plate during evoked maximal incisal clenching. After death, bone was removed from the mandibles around and under the plates and examined. Gross dimensions and density were measured. An ultrasonic technique was used to measure the material properties, including the elastic and shear moduli.

RESULTS

Bone strain inferior to the plates was reduced by 34% to 53% after attachment of the thick plates. Little change in strain was found after attachment of the thin plates. However, no significant differences in structural or mechanical measurements, such as density, cortical thickness, elastic and shear moduli, and Poisson's ratios, were detected between the two sides in each monkey.

CONCLUSION

Long-term placement of bone plates, and the resulting stress shielding, were found to result in structural changes in the mandibular corpus.

Chronic Low Dose Growth Hormone Treatment Stimulates Both Hypertrophy and Hyperplasia of Remnant Kidneys in Uraemic Rats

CONCLUSION

In conclusion, low doses of exogenous rhGH, when administered in a manner similar to clinical practice, are associated with glomerular enlargement and stimulation of hypertrophy and hyperplasia of remnant kidneys from uraemic rats. Increased GV was also seen after short term, high dose rhGH therapy in our previous study.([4]) The time interval required before increased GV develops with low dose rhGH therapy and whether or not further rhGH exposure subsequently leads to worsening glomerular hypertrophy, glomerulosclerosis([7]) and renal failure cannot be determined from the current study. Although we observed no significant changes in renal function with rhGH therapy, we recommend that children with CRI be carefully monitored to ensure that long term rhGH treatment has no such deleterious effects.

Functional characteristics of retrognathic patients before and after mandibular advancement surgery

PURPOSE

The purpose of this investigation was to compare morphologic parameters and functional performance between controls and a sample of patients with mandibular retrognathia prior to surgical correction, and to examine how oral motor function adapts after treatment.

PATIENTS AND METHODS

Twenty-four retrognathic female patients were compared with 26 female controls before and up to 3 years after mandibular advancement surgery. Measures of skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyographic activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way analysis of variance was used to compare the controls, the patients before surgery, and the patients after surgery.

RESULTS

Surgical lengthening of the mandible averaged 7.3 mm, bringing most skeletal measures into the normal range. There were no significant differences in jaw muscle mechanical advantage between patients and controls before surgery, but surgery significantly reduced mechanical advantage of the anterior temporalis and masseter muscles. Jaw hypomobility was apparent at 6 weeks after surgery, but returned to normal values within 12 to 24 months. Before surgery the patients had maximum isometric bite forces less than half those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 years. Before surgery the patients' muscle activity levels per unit of bite force were equivalent to those of controls or somewhat higher. After surgery some of the patients' muscles had significantly lower levels of muscle activity per unit of bite force than did controls.

CONCLUSION

The results of this study suggest that correction of mandibular retrognathia by mandibular advancement surgery produces some significant functional benefits.

A longitudinal study of changes in masticatory performance of patients undergoing orthognathic surgery

PURPOSE

Individuals with developmental deformities of the jaws may be less efficient at chewing food. Previous studies have reported masticatory deficiency in patients with such deformities. This study was designed to detect any changes in masticatory performance that accompany orthognathic surgery.

MATERIALS AND METHODS

Masticatory performance was tested in 18 patients with various jaw deformities before application of orthodontic appliances and 2 to 3 years after surgical correction of their malocclusion. A control group was tested at three 6-month intervals. The subjects chewed carrots and masticatory performance was measured using a standard sieve technique. The Rosin-Rammler equation was used to calculate the median particle size and broadness index of each set of carrots. The number of chewing cycles required for each subject to swallow one piece of carrot was also recorded.

RESULTS

A statistically significant difference in median particle size between patients and controls was found both preoperatively and postoperatively (P < .05), but no difference in median particle size or broadness index was seen between trials for controls or patients (P > .05).

CONCLUSION

It was concluded that before surgery patients have a lower level of performance than controls and surgical correction of the malocclusion does not significantly enhance performance.

The effects of orthodontic treatment on isometric bite forces and mandibular motion in patients before orthognathic surgery

PURPOSE

Little is known about the effects of orthodontic treatment on oral motor function. The objective of this report is to evaluate changes in mandibular motion and maximum bite force that occur between the initiation of presurgical orthodontics and its completion before surgery.

PATIENTS AND METHODS

Fifteen patients (9 women, 6 men) with a variety of dentofacial deformities were examined before and after presurgical orthodontics. Mechanical advantage of the muscles and bite points, mandibular range of motion, maximum isometric bite force, and levels of electromyographic (EMG) activity in the anterior and posterior temporalis and masseter muscles during isometric bites were recorded on all subjects over time. Data obtained before and after completion of presurgical orthodontics were statistically compared.

RESULTS

Presurgical orthodontics reduced mandibular mobility somewhat, but the amount was not significant. Statistically significant reductions in bite force were noted after orthodontics for incisor, canine, premolar, and molar bite positions. No significant difference in the EMG/bite force slopes was obtained, nor was there any difference in the moment arms of the bite points or the muscles of mastication from orthodontics.

CONCLUSIONS

This study showed significant changes in measures of oral motor function resulting from orthodontic treatment. A larger study is needed to confirm that these results will be similar in all orthodontic patients. There is no indication that these changes are the result of physiologic alterations of the muscles of mastication. The best current explanation is that these changes result from the pain and discomfort of the orthodontic appliances and the induced malocclusion.

Breathing patterns during spontaneous speech

Lung volumes, speech intensity, the linguistic location of inspirations, and the variability of each, were studied during spontaneous speech in 6 healthy young women over 7 to 10 sessions each, using respiratory inductance plethysmography. Although average lung volume levels were within the vital capacity range previously reported for speech (Hixon, Goldman, & Mead, 1973), significant inter- and intrasubject variability was observed. This variability was considerable for some subjects (average initiation lung volume varying between 42 and 63% VC over the sessions) and relatively small for others (between 47 and 53% VC). Some of the lung volume variation was associated with changes in mood state, examined by self-report questionnaire at each measurement occasion. Linguistic factors were important influences in the lung volume variation. The majority of breaths in the conversations and monologues preceded structural (clause) boundaries. The volume of air inspired preutterance was found to be linked to the length of the ensuing breath group in each of our 6 subjects, as longer breath groups, spanning up to seven clauses in the spontaneous speech, were anticipated by inspiring to a higher lung volume. The subjects used a comfortable speaking intensity range, which varied for different individuals and sessions over 4 to 18 dB. Increases in speech intensity within individual ranges were not associated with increased lung volumes. The data provide novel insight into associations between physiological and linguistic factors in the control of speech breathing, and are suggestive of the existence of neural planning of the respiratory system, in anticipation of the demands of the utterance.

Connective tissue forces from mandibular advancement

PURPOSE

To quantify the connective tissue forces generated during surgical lengthening of the mandible.

PATIENTS AND METHODS

Sixty-three patients who had mandibular advancements by sagittal ramus osteotomy were used in this study. Prior to sectioning the rami, the overjet was recorded. After sectioning the rami, a spring-gauge was attached to the mandibular orthodontic wire and pulled anteriorly to determine how much force was necessary to bring the mandibular incisors into a Class I relationship with the maxillary incisors. Aggressive stripping of the perimandibular periosteum and connective tissues on the distal segment was then performed. The amount of force was again recorded.

RESULTS

The mean preoperative overjet in the 63 patients was 6 mm (range, 3 to 11 mm). The mean amount of force required to advance the mandible prior to stripping the tissues was 1,498 g compared with a mean of 787 g after stripping (P < .001). There were statistically significant correlations between the preoperative overjet and the prestripping and poststripping force levels (P < .001). There was also a significant relationship between prestripping and poststripping values (P < .001).

CONCLUSION

The results of this study indicate that orthopedic forces are generated by the perimandibular connective tissues following advancement by the mandible. The effect of these forces on the temporomandibular joint should be evaluated in future studies.

Treatment of mandibular angle fractures using two noncompression miniplates

PURPOSE

To evaluate treatment with two 2.0-mm noncompression miniplates for patients with angle fractures.

PATIENTS AND METHODS

Sixty-seven consecutive patients with 69 fractures of the mandibular angle were treated by open reduction and internal fixation using two noncompression miniplates and 2.0-mm self-threading screws placed through a transoral incision with transbuccal trochar instrumentation. No patient was placed into postsurgical maxillomandibular fixation or elastics.

RESULTS

Overall, 19 fractures (28%) experienced complications requiring secondary surgical intervention. Most of the complications were postoperative infections requiring surgical drainage (n = 17) and subsequent hardware removal (n = 16). Of the 17 infected fractures, 11 were healed at the time of hardware removal and required no further treatment. Five were still mobile and required a period of maxillomandibular fixation for healing. One of the fractures did not heal and required bone grafting.

CONCLUSION

The use of two noncompression miniplates was found to be relatively easy, but resulted in an unacceptable rate of infection in our patient population when used for treatment of fractures of the mandibular angle.

Guidelines for measurement of blood pressure, follow-up, and lifestyle counselling. Canadian Coalition for High Blood Pressure Prevention and Control

As part of the Coalition's mandate to promote the prevention and control of high blood pressure in Canada, an interdisciplinary Workgroup was established to review and update the existing standards (1987) for blood pressure measurement and referral guidelines. The intent was to prepare a scientifically based document which contained practical guidelines for the measurement of blood pressure and criteria for follow-up, and one which promoted the concept of cardiovascular health in the assessment and interpretation of blood pressure readings. These guidelines were primarily developed to assist primary health care providers and/or clinicians to assess, monitor, counsel, refer, and develop treatment plans for adults-at-risk for high blood pressure or those with the confirmed diagnosis of hypertension. Readers are referred to The Canadian Hypertension Society Consensus Conference series (Canadian Medical Association Journal 1993) for specific guidelines on the evaluation, diagnosis, and treatment of hypertension. The document is divided into three sections: 1. Measurement of blood pressure 2. Criteria for follow-up 3. Guidelines for lifestyle counselling Each section cites the references used in developing the guidelines and where relevant, identifies other resources which can be used in clinical practice.

Bite forces in patients treated for mandibular angle fractures: implications for fixation recommendations

Voluntary bite forces were recorded at varying periods in 35 males treated with rigid internal fixation for fractures of the mandibular angle. Bite forces were also obtained in 29 male controls for comparison. It was found that molar bite forces in patients were significantly less than in controls for several weeks after surgery. Further, molar bite forces on the side of the fracture were significantly less than on the nonfractured side. The results of this study indicate that recommendations for the amount of fixation required for a given fracture may be reduced.

Variability and consistency in speech breathing during reading: lung volumes, speech intensity, and linguistic factors

Lung volumes during reading and associated factors such as speech intensity and linguistic influences were studied in six healthy young women over 7 to 10 sessions, using respiratory inductive plethysmography. Intrasubject variability of lung volumes over the sessions was almost as great as the intersubject variability. Some of the intrasubject variability was associated with natural variations of speech intensity within a "comfortable loudness" range. The lung volume variability during reading is contrasted with high degrees of both inter- and intrasubject consistency in the location of inspirations, which occurred almost exclusively at grammatically appropriate places in the texts (paragraph, sentence, clause, and phrase boundaries). Within each reading passage, lung volumes were significantly increased for (a) louder utterances, (b) inspirations at sentence and paragraph boundaries compared to inspirations at other locations within sentences, (c) longer utterances compared to shorter utterances, and (d) initial breaths compared to final breaths. The implications of these findings for the neural control of breathing during speech are considered.