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Biomedical subjects

R A Bays

Publications and source records attributed to R A Bays.

At least 19 recordsLinked to original sources
PubMed2001

Positional change of the hyoid bone after bilateral sagittal split osteotomy with rigid and wire fixation.

The purpose of this study was to compare positional changes of the hyoid bone and the amount of postsurgical compensation in mandibular position in patients who received either wire or rigid fixation after surgery. Data were analyzed from 97 patients (25 males and 72 females) who were randomized to receive wire (43) or rigid (54) fixation after mandibular advancement surgery as part of a multicenter clinical trial. Radiographs were digitized before surgery (T2), immediately after surgery (T3), and 8 weeks (T4), 6 months (T5), 1 year (T6), and 2 years (T7) after surgery. The wire group had greater sagittal relapse of the hyoid bone at T6 (P =.007), which persisted at T7 (P =.02). Both groups showed upward movement of the hyoid bone after surgery. There was no relationship between the vertical change in the the hyoid bone position and the vertical position of mandible (B point y coordinate, mandibular plane). However, there was a relationship between the horizontal hyoid bone position and B point during the postsurgical period (rigid, r = 0.450; wire, r = 0.517). The direct distance from the hyoid bone to basion increased (P <.001) in both groups at T3 and then recovered its original length after 8 weeks (P <.001). The rigid group showed no significant change in distance from the hyoid to the genial tubercles, but the wire group showed recovery of the muscle length at T6 (P <.05) and T7 (P <.05).

Bone Wires↗
PubMed2001

Mandibular range of motion after bilateral sagittal split ramus osteotomy with wire osteosynthesis or rigid fixation.

OBJECTIVES: An analysis was conducted to compare mandibular range of motion among Class II patients treated with wire osteosynthesis or rigid internal fixation after surgical mandibular advancement. STUDY DESIGN: Patients randomly received wire osteosynthesis and 8 weeks of maxillomandibular fixation (n = 49) or rigid internal fixation (n = 78). Mandibular range of motion was measured 2 weeks before surgery and 8 weeks, 6 months, and 1, 2, and 5 years after surgery. RESULTS: Both groups showed decreased mobility in all movement dimensions that progressively recovered to near presurgical levels over the 5-year follow-up period. The difference in range of motion between treatment groups was not statistically significant. Changes in proximal and distal segment position could not explain decreased mobility. CONCLUSIONS: Similar decreases in mandibular mobility occurred with wire and rigid fixation of a bilateral sagittal split ramus osteotomy after surgery. Long-term changes were statistically, but not clinically, significant.

Adult↗
PubMed2001

Maintenance of soft tissue changes after rigid versus wire fixation for mandibular advancement, with and without genioplasty.

OBJECTIVE: This multisite prospective randomized clinical trial examined 2-year longitudinal soft tissue profile changes after bilateral sagittal split osteotomy for mandibular advancement by using rigid or wire fixation, with and without genioplasty. STUDY DESIGN: The study sample consisted of 127 subjects. The rigid-fixation group (n = 78) received 2-mm bicortical position screws, whereas the wire-fixation group (n = 49) received inferior border wires. In the rigid-fixation group, 35 subjects underwent genioplasty, whereas 24 subjects underwent genioplasty in the wire-fixation group. Soft tissue profile changes of labrale inferius, B-point, and pogonion were obtained from digitized cephalometric films taken immediately before surgery and up to 2 years after surgery. RESULTS: Regardless of fixation technique, subjects who had genioplasty in conjunction with the mandibular advancement had the largest surgical movement and the largest postsurgical change (P <.05). When all variables were constant, fixation technique was associated with maintenance of soft tissue change. Subjects who underwent rigid fixation maintained more soft tissue change than patients who underwent wire fixation. CONCLUSIONS: These findings suggest that subjects undergoing rigid fixation and genioplasty maintained the most soft tissue advancement.

Adult↗
PubMed2000

Bilateral sagittal split osteotomy and temporomandibular disorders: rigid fixation versus wire fixation.

OBJECTIVE: The effects of orthognathic surgery on temporomandibular disorders may be related to the surgical method that is used. Specifically, it has been suggested that the choice of stabilization technique may play a major role in the functional outcome of mandibular advancement surgery. The purpose of this study was to prospectively compare long-term (2 years) signs and symptoms of temporomandibular disorders after orthognathic surgery with bilateral sagittal split osteotomy in 127 patients randomized to receive rigid or wire fixation. STUDY DESIGN: Signs and symptoms of temporomandibular disorders were evaluated before and 2 years after surgery by means of the overall craniomandibular index (CMI), dysfunction index (DI), and muscle index (MI). Patients also reported subjective symptoms of temporomandibular disorders by marking areas of pain on a standard drawing of the head and rating the pain in each area on a scale ranging from 1 (very mild) to 7 (very extreme). Subjective pain was also assessed through use of the Oral Health Status Questionnaire and by a rating of the difficulty in opening the mouth because of pain. RESULTS: There were no statistically significant differences in the CMI, MI, or DI change scores between the wire and rigid fixation groups (mean CMI(wire) = 0.05, mean CMI(rigid) = 0.04; mean DI(wire) = 0.02, mean DI(rigid) = 0. 01; mean MI(wire) = 0.08, mean MI(rigid) = 0.08) 2 years after surgery. Temporomandibular joint sounds also demonstrated no significant differences between the two fixation methods. Subjective pain reports were consistent with the clinical examinations. On average, both wire and rigid scores decreased slightly, but the change scores were not significantly different between groups. CONCLUSIONS: These findings suggest that the long-term (2 years) effects of wire and rigid internal fixation methods on the signs and symptoms of temporomandibular disorders do not differ. Earlier concerns about increased risk for temporomandibular disorders with rigid fixation were not supported by these results.

Adult↗
PubMed2000

Skeletal stability after mandibular advancement with rigid versus wire fixation.

PURPOSE: This study examined the stability of skeletal changes after mandibular advancement surgery with rigid or wire fixation up to 2 years postoperatively. PATIENTS AND METHODS: Subjects for this multisite, prospective, clinical trial received rigid (n = 78) or wire (n = 49) fixation. The rigid cases were fixed with three 2-mm bicortical position screws and 1 to 2 weeks of skeletal maxillomandibular fixation with elastics, and the wire fixation subjects were fixed with inferior border wires and had 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric radiographs were obtained before orthodontics, immediately before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Linear cephalometric changes were referenced to a cranial base coordinate system. RESULTS: Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior sagittal advancement of the mandibular symphysis was 4.92 +/3.01 mm in the rigid group and 5.11 +/- 3.09 mm in the wire group, and the inferior vertical displacement was 3.37 +/- 2.44 in the rigid group and 2.85 +/- 1.78 in the wire group. The vertical changes were similar in both groups. Two years postsurgery, the wire group had 30% sagittal relapse of the mandibular symphysis, whereas there was no change in the rigid group (P < .001). Both groups experienced changes in the orientation and configuration of the mandible. CONCLUSIONS: Rigid fixation is a more stable method than wire fixation for maintaining mandibular advancement after sagittal split ramus osteotomy.

Adult↗
PubMed2000

Neurosensory differences after wire and rigid fixation in patients with mandibular advancement.

PURPOSE: The purpose of this analysis was to compare the frequency and severity of nerve damage with rigid and wire fixation in patients participating in a prospective, randomized clinical trial. PATIENTS AND METHODS: One hundred twenty-six patients who required a bilateral sagittal split osteotomy and mandibular advancement were randomly assigned to receive either rigid or wire fixation. Tactile sensation in the mental nerve region bilaterally was determined presurgically and throughout the subsequent 2 years by using monofilament detection and brush stroke direction. Neurosensory levels were compared between the types of fixation over time. RESULTS: Evaluation with monofilament detection showed no significant difference between types of fixation throughout the 2-year follow-up. However, brush stroke determination showed significantly greater hypesthesia with rigid compared with wire fixation from 8 weeks through 2 years postoperatively. CONCLUSION: Rigid fixation resulted in more anesthesia in the mental nerve distribution than wire fixation when tested with brush stroke direction. However, increased anesthesia was not present when measured with monofilament determination.

Adolescent↗
PubMed2000

Neurosensory recovery after ligation of the descending palatine neurovascular bundle during Le Fort I osteotomy.

PURPOSE: The effect of ligating the descending palatine neurovascular bundle (DPNB) on the recovery of palatal sensation has not been clearly established. The purpose of this study was to determine the effect of ligation of the DPNB on the recovery of palatal sensation after Le Fort I osteotomy. PATIENTS AND METHODS: Using a retrospective study design in a randomized protocol, patients who had undergone Le Fort I osteotomy were assigned to either treatment group 1 (DPNB ligated) or treatment group 2 (DPNB preserved). A third group of control patients (group 3, unoperated) on whom no surgery had been performed served as a baseline for examination of normal palatal sensation. The predictor variables were ligation and preservation of the DPNB. The outcome variables were mean tactile sensation and mean nociception. Other study variables included age, sex, follow-up, surgical movements, and number of segments. RESULTS: There were 11 patients in group 1, 7 in group 2, and 10 in group 3. For tactile sensation, the mean Von Frey hair size detected was 4.26 +/- 0.37, 4.11 +/- 0.17, and 3.68 +/- 0.24 for groups 1, 2, and 3, respectively. The difference between group 1 and group 2 was not significant (P > .05). The differences between group 1 and group 3 and between group 2 and group 3 were significant (P < .05). For nociception, the mean pressure was 51.09 +/- 21.73, 50.89 +/- 19.19, and 56.25 +/- 19.02 for groups 1, 2, and 3, respectively. The difference between the 3 groups was not significant (P = .8064). CONCLUSION: The results of this study suggest that recovery of palatal sensation is not adversely affected by ligation of the DPNB.

Adult↗
PubMed2000

Patients' own reasons and patient-perceived recommendations for orthognathic surgery.

In an attempt to learn more about patients' decision-making processes, an analysis was performed to examine patients' reasons for undergoing orthognathic surgery and their understanding of the reasons surgery was recommended. Before surgery, 105 females and 38 males completed an open-ended questionnaire in which they listed their reasons for choosing orthognathic surgery and their perceptions of their orthodontists' recommendations. Three raters classified the responses into 7 categories: esthetics, psychosocial, functional, TMJ/pain, authority, prevention, and other. Rater agreement ranged from a kappa of.55 to 1.00. Patients reported undergoing orthognathic surgery primarily for esthetic, functional, and TMJ improvements, 71%, 47%, and 28%, respectively. Females reported more TMJ-related reasons than males (P <.05). Patients reporting function (P <. 05), TMJ (P <.05), and prevention of future problems (P <.05) were older than patients not reporting these reasons. Mexican American patients indicated more psychosocial reasons (P <.05) than European Americans. Patients understood that orthognathic surgery was recommended primarily for esthetic, functional, and TMJ improvements, 52%, 44%, and 18%, respectively. Males reported receiving more preventative recommendations (23%) than females (10%). Mexican American patients reported receiving more psychosocial recommendations (P <.05) than European Americans. Agreement between each paired patient/patient-perceived reason was highest for TMJ problems (kappa = 0.588). In conclusion, patients underwent orthognathic surgery to improve esthetic, functional and TMJ problems and interpreted orthodontists' recommendations for similar reasons. On a case-to-case basis, agreement between patient and orthodontist-represented reasons was modest, suggesting differences between patients' own reasons and their perceptions of orthodontists' recommendations.

Adolescent↗
PubMed2000

A comparative study of skeletal and dental stability between rigid and wire fixation for mandibular advancement.

This study examined the skeletal and dental stability after mandibular advancement surgery with rigid or wire fixation for up to 2 years after the surgery. Subjects for this multisite, prospective, randomized, clinical trial were assigned to receive rigid (n = 64) or wire (n = 63) fixation. The rigid cases received three 2-mm bicortical position screws bilaterally and elastics; the wire fixation subjects received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Skeletal and dental changes were analyzed using the Johnston's analysis. Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior advancement of the mandibular symphasis was 5.5 mm (SD, 3.2) in the rigid group and 5.6 mm (SD, 3.0) in the wire group. Two years after surgery, mandibular symphasis was unchanged in the rigid group, whereas the wire group had 26% of sagittal relapse. Dental compensation occurred to maintain the corrected occlusion, with the mandibular incisor moving forward in the wire group and posteriorly in the rigid group. However, at 2 years after surgery, when most subjects were without braces, the overjet and molar discrepancy had relapsed similarly in both groups.

Adolescent↗
PubMed2000

Psychosocial predictors of satisfaction among orthognathic surgery patients.

This study assessed the usefulness of selected psychosocial tests and demographic measures in identifying satisfied versus dissatisfied patients who received orthognathic surgery. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, 12 months and and 2 years postsurgery. The Revised Symptom Checklist-90 (SCL-90-R) scales, the Eysenck Personality Inventory (EPI), the Sickness Impact Profile (SIP), and the Oral Health Status Questionnaire (OHSQ) were used as independent variables. Indicators from the Post-Surgical Patient Satisfaction Questionnaire (PSPSQ), which assesses patient satisfaction regarding psychosocial issues, oral functioning, and esthetics, served as a postsurgical dependent measure of patient satisfaction. Thirty-one male and 86 female subjects participated in the multisite randomized trial comparing rigid and wire fixation. Patient age was significantly correlated with patient satisfaction from 8 weeks postsurgery through 2 years postsurgery. Older patients appear to report greater postsurgical satisfaction in comparison to younger patients. The postsurgical OHSQ (esthetics subscale) and postsurgical PSPSQ (satisfaction) were significantly related at 8 weeks, 6 months, 12 months, and 2 years postsurgery. Additionally, PSPSQ (satisfaction) and postsurgical OHSQ (general oral health scale) were correlated at 12 months. The EPI, SIP, and SCL-90-R were not significantly associated with postsurgical satisfaction when assessing the entire study sample. Postsurgical qualitative data from the PSPSQ indicated that 50% of the patients reported positive outcomes in oral functioning. Sixty-five percent reported esthetic improvements, and 37% reported neurosensory loss.

Adult↗
PubMed1999

Evaluation of suspected pulmonary embolism utilizing end-tidal CO2 and D-dimer.

BACKGROUND: The study prospectively assesses deadspace [(arterial CO2 - end-tidal CO2)/arterial CO2] and the D-dimer assay as a rapid, noninvasive alternative for evaluating pulmonary embolism in critically ill patients. METHODS: Group I patients had nonemergency baseline arterial blood gas and end-tidal CO2 recorded. If patients experienced respiratory distress, D-dimer with repeat arterial blood gas and end-tidal CO2 were obtained. Patients emergently intubated without baseline laboratory studies (group II) had arterial blood gas, end-tidal CO2, and D-dimer obtained. RESULTS: A significant increase (P <0.001) in deadspace was noted with pulmonary embolism (0.43 [0.08], range 0.30 to 0.51, n = 7) versus without (0.21 [0.15], range 0.00 to 0.43, n = 14). Patients in group 1 with pulmonary embolism demonstrated increased deadspace (P <0.026, 0.28 [0.01] to 0.39 [0.13], n = 2) from baseline compared with decreased deadspace (P <0.001, 0.20 [0.09] to 15 [0.16], n = 9) without pulmonary embolism. D-dimer levels >1,000 ng/mL were present in all patients with pulmonary embolism. CONCLUSIONS: The study demonstrates the ability of deadspace and D-dimer to exclude and potentially diagnose pulmonary embolism.

Angiography↗
PubMed1999

Psychological function in orthognathic surgical patients before and after bilateral sagittal split osteotomy with rigid and wire fixation.

A multisite randomized controlled trial was conducted to compare the psychological function of patients who undergo surgical correction of a Class II malrelation with bilateral sagittal split osteotomy with either wire or rigid fixation. Subjects were 31 male and 86 female patients referred by orthodontists. Psychopathological symptoms and psychological distress were measured with the Symptom Checklist-90 Revised at the following times: before placement of orthodontic appliances, 1 to 2 weeks presurgery, and 1 week, 8 weeks, 6 months, and 2 years postsurgery. Patients' satisfaction with their surgical outcome was measured with a 3-item questionnaire. Results showed no statistically significant differences in psychological function or satisfaction between patients treated with wire or rigid fixation. Psychological function was within normal limits immediately before surgery. Psychological parameters did not determine patient satisfaction, even among patients who met an operational definition of "psychopathological caseness." Psychological symptoms and general distress increased modestly immediately after surgery for both groups and then progressively declined over the succeeding 2 years, eventually reaching levels that were significantly lower than presurgical levels. It was concluded that (1) rigid and wire fixation do not differ in their effects on psychological function and satisfaction; (2) patients who seek orthognathic surgery for a Class II malocclusion are psychologically healthy, ie, comparable to normal populations, immediately before surgery; (3) presurgical psychological function does not determine satisfaction with surgical outcome; and (4) psychological function tends to improve during the 2 years after surgery.

Adult↗
PubMed1999

Psychosocial predictors of high-risk patients undergoing orthognathic surgery.

The purpose of this analysis was to identify a set of predictor variables that are prospectively related to postsurgical outcomes. Specifically, psychosocial characteristics were sought to predict postsurgical outcomes. The 5 Revised Symptom Checklist-90 (SCL-90-R) scales, the neuroticism score of the Eysenck Personality Inventory (EPI), the psychosocial domain score from the Sickness Impact Profile (SIP), and 4 scales from the Oral Health Status Questionnaire (OHSQ) were used as the predictors. A total of 31 male and 86 female subjects participated in this multicenter randomized trial, which compared rigid and wire fixation. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, and 2 years after surgery. Baseline oral health was used as an indicator of postsurgical oral health functioning. A path analytic model of influences on presurgical oral health was estimated (R2 = 0.43). The results suggest that presurgical screening of demographic characteristics (age, sex, and ethnicity), oral health (the OHSQ), quality of life issues (SIP), and personality features (SCL-90-R), accounts for 23% to 39% of the variance in postsurgical oral health outcomes. The path analysis conducted suggests that a patient's age, ethnicity, gender, and elevated scores on the EPI have indirect effects on postsurgical health. As determined by a 2-stage least squares regression model, 3 variables--the patient's presurgical oral health (per the OHSQ), pre- and postsurgical Global Severity Index (GSI) score from the SCL-90-R, and the psychosocial scale score from the SIP--were found to have a statistically significant impact on postsurgical outcomes. Additionally, the GSI, SIP, and OHSQ are reliable measures in predicting oral health outcomes.

Adult↗
PubMed1998

Effects of hypesthesia on oral behaviors of the orthognathic surgery patient.

PURPOSE: The purpose of this study was to compare orthognathic surgery patients with and without significant hypesthesia with respect to perceived problems with specific oral behaviors. PATIENTS AND METHODS: Data from 116 patients 6 months after bilateral sagittal split osteotomy (BSSO) and mandibular advancement were analyzed. Tactile sensation in the right and left mental nerve areas was determined using monofilaments and brush strokes (von Frey hairs). The right infraorbital region was used as a control. A difference of 450 mg of force between the control and test sites was considered significant hypesthesia. Patients rated their level of subjective problems with swallowing liquids or solids, smiling, spitting, kissing, speaking, eating, and drooling on a scale from 1 (none to mild) to 7 (extreme). A value of 5 or greater was considered significant impairment. RESULTS: Hypesthesia was shown in 23 patients (19.8%) with the monofilaments and in 29 patients (25.0%) using brush stroke direction. In each of these two groups, a significant correlation was observed between hypesthesia and difficulty in chewing and kissing. No correlation was observed between any of the remaining seven oral behaviors and hypesthesia. CONCLUSION: These findings suggest that only certain oral behaviors are affected by hypesthesia of the mental nerve.

Adolescent↗
PubMed1998

Health-related quality of life following orthognathic surgery.

A randomized controlled trial was conducted to compare the effects of rigid and wire fixation on health-related quality of life following surgical mandibular advancement in patients with Class II malocclusions. Sixty-four patients randomly selected to receive rigid fixation with bicortical position screws were compared with 63 patients randomly selected to receive nonrigid fixation with inferior border wires. Quality of life was measured using the Sickness Impact Profile, a generic measure of health-related quality of life, and the Oral Health Status Questionnaire, a specific measure of oral health and function designed for use with orthognathic surgery patients. Patients were evaluated prior to application of orthodontic appliances, approximately 2 weeks before surgery, and 1 week, 8 weeks, 6 months, 1 year, and 2 years following surgery. Neither instrument revealed a statistically significant difference in quality of life between wire and rigid fixation at any time period. The health-related disability associated with Class II malocclusion is modest compared to many other medical conditions. Nonetheless, orthognathic surgery patients exhibit progressive and statistically significant improvement in health-related quality of life across a wide variety of functional domains, regardless of the fixation method used.

Adolescent↗
PubMed1998

Effects of major Class II occlusal corrections on temporomandibular signs and symptoms.

This study explored the relationship between malocclusion and signs and symptoms of temporomandibular disorders (TMD) in 124 patients with severe Class II malocclusion, before and 2 years after bilateral sagittal split osteotomy (BSSO). Patients were evaluated with the Craniomandibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to assess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index scores dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 years postsurgery (P < 0.001). The CMI and masticatory index (MI) for muscle pain indicated clinically small but statistically significant improvement (P = 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0.15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 33 (26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnitude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.

Adolescent↗
PubMed1997

Maxillary perfusion during Le Fort I osteotomy after ligation of the descending palatine artery.

PURPOSE: Controversy exists regarding management of the descending palatine artery (DPA) during Le Fort I osteotomy. Some surgeons advocate preserving the DPA, and others ligate the vessels. The purpose of this study was to evaluate maxillary gingival blood flow (GBF) during Le Fort I osteotomy in a sample of patients with and without ligation of the DPA. PATIENTS AND METHODS: Using a prospective randomized clinical study, we enrolled a study sample composed of 34 patients undergoing Le Fort I osteotomy. The patients were randomly assigned to either study group 1 (16) (DPA ligated) or group 2 (18) (DPA preserved). To measure maxillary GBF during the operation, we used laser Doppler flowmetry (LDF). The predictor variable was status of DPA management (ligated or preserved). The outcome variable was change in GBF over time. RESULTS: (DPA). Before ligation (or simulated ligation) of the DPA, the mean GBF for groups 1 and 2 was 11.4 +/- 8.6 and 11.9 +/- 9.4 mL/min/100 g tissue, respectively (P = .88). After ligation of the DPA in group 1, the mean GBF was 10.0 +/- 7.7 mL/min/100 g tissue. At the corresponding time in group 2 (DPA preserved), the mean GBF was 12.6 +/- 9.4 mL/min/100 g tissue. The difference in mean GBF between groups 1 and 2 was not statistically significant (P = .43). CONCLUSION: There were no statistically significant differences in mean maxillary GBF between patients having the DPA ligated and those having the DPA preserved as measured using LDF during Le Fort I osteotomy.

Adolescent↗