Prediction of periodontal pathology around third molars using linear mixed effects modeling.

OBJECTIVE: To compare the random intercept multilevel model with other linear mixed effects models in an assessment of the effect of quadrant-, jaw-, and person level covariates on probing depth of asymptomatic third molars. BASIC RESEARCH DESIGN: Five different covariance models were considered: 1) the random intercept multilevel 2) multi-level with unequal jaw variance 3) multi-level with unequal tooth variance 4) multi-level with unequal jaw and side variance and 5) the general linear model for correlated data with unstructured covariance matrix. PARTICIPANTS: 235 subjects with all four third molars erupted were included. Fifty-one percent were female and 75% Caucasian. The average age was 29.1 years (sd = 7.0). RESULTS: The extended multi-level with unequal residual variance was the best fit to the data. Likelihood ratio tests in a stepdown selection approach resulted in a final model for mean probing depth that included one statistically significant three-way interaction (age x gingival inflammation x gender), two statistically significant two-way interactions (jaw x gingival inflammation and jaw x gender) and one significant main effect (ethnicity). CONCLUSIONS: Linear mixed effects modeling is a powerful tool for the analysis of correlated dental data. However, no one covariance structure is appropriate for all purposes.

A biomechanical evaluation of mandibular angle fracture plating techniques.

PURPOSE: The purpose of this investigation was evaluate the biomechanical behavior of a vast array of fixation philosophies and techniques that address mandibular angle fractures. MATERIALS AND METHODS: A total of 150 polyurethane synthetic mandible replicas (Synbone, Laudquart, Switzerland,) were used in this investigation. Five controls and 5 each of 14 different fixation philosophies and techniques were subjected to vertical loading at the incisal edge and then repeated for contralateral loading in the molar region by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. The fixation philosophies and techniques evaluated were the lag screw technique, monocortical superior border plating techniques with varying sizes of plates and screws, monocortical 2-plate techniques with varying forms of fixation, monocortical tension band systems with associated bicortical stabilization plates of various types, and various forms of reconstruction plates. Load/displacement data within a 0 to 200 N range were recorded. Yield load, yield displacement, and stiffness were determined. Mean and standard deviations were calculated, and statistically significant differences within and among categories were determined using an analysis of variance (P <.05). Second-order polynomial best-fit curves were also created for each group to further evaluate and compare the mechanical behavior. RESULTS: For incisal edge loading, statistically significant differences (P <.05) were found for stiffness between some of the monocortical superior border fixation techniques, as well as for yield displacement between several forms of monocortical 2-plate fixation techniques. No other differences were found within categories or among the groups that best represented their categories. For contralateral molar loading, statistically significant differences existed within and among categories. CONCLUSIONS: Under the conditions of this experiment, all systems met or exceeded currently identified postoperative functional requirements for incisal edge loading, but failed to meet them for contralateral molar loading.

The changing face of odontogenic infections.

PURPOSE: The purpose of this investigation was to compare characteristics of patients hospitalized with odontogenic infections during the 1980s to those of the 1990s. PATIENTS AND METHODS: This study was a retrospective record review that compared 2 cohorts of patients admitted to the same institution during two 81-month periods, one decade apart. Admission criteria were face or neck swelling suggesting abscess or cellulitis and one or more of the following: temperature above 38 degrees C, white blood cell (WBC) count greater than 10.8 x 10(3)/microL, or concern about airway compromise. Characteristics reviewed were age, gender, race, admission temperature, admission WBC count, fascial space(s) involved, tooth of etiology, duration of hospitalization, and bacteria isolated. Data were compared for statistical significance (P <.05). RESULTS: No significant differences were found between the 2 cohorts for age, gender, race, admission temperature, admission WBC count, space involvement, or length of stay (P <.05). One tooth (mandibular left first molar) of 52 was involved more frequently in the 1990 group (P <.03). Gram-positive cocci were isolated significantly more frequently from the 1990s patients than from the 1980s patients (P <.03). There were also significant differences (P <.02) between cohorts in the isolation frequency of individual genera, such as alpha-hemolytic Streptococci, coagulase negative staphylococci, Staphylococcus epidermidis, Bacteroides melanogenicus, beta-lactamase positive Bacteroides, Eikenella corrodens, and Neisseria species. Eighty-one percent of the bacteria cultured from the 1990s patients were resistant to one or more common antibiotics; 47% of these organisms were Staphylococcus aureus. CONCLUSION: No clinically significant differences existed in the characteristics of patients hospitalized with odontogenic infections between the 1980s and the 1990s. Although there were differences in the type and prevalence of bacteria isolated, this was probably a result of changes in nomenclature, identification protocols, and isolation techniques.

Outcomes of open versus closed treatment of mandibular subcondylar fractures.

OBJECTIVES: The purpose of this study was to compare the long-term treatment results of open reduction and rigid internal fixation (ORIF) with closed reduction and maxillomandibular fixation (CRMMF) for subcondylar fractures when guided by specific indications and contraindications. PATIENTS AND METHODS: A protocol for the treatment of condylar process fractures was developed that included absolute and relative indications and contraindications as well as a technique regimen. To evaluate the results of this protocol, 10 patients treated with CRMMF and 10 treated by ORIF were recalled after a minimum of 6 months and examined for gender, race, diagnosis, age at injury, time since operation, and cause of the fracture. Each group was assessed by 2 blinded investigators for maximum interincisal opening, right lateral excursion, left lateral excursion, protrusive movement, deviation on opening, scar perception, motor function, sensory perception, contour perception, occlusion, and perception of pain. Nonparametric data were compared for statistical significance with a chi-square analysis and parametric data with an independent samples t-test (P < .05). RESULTS: No statistically significant differences existed between the ORIF and CRMMF groups for gender, race, diagnosis, or cause. Moreover, no differences existed for age at injury, maximum interincisal opening, right lateral excursion, left lateral excursion, protrusive movement, deviation on opening, or occlusion. Differences were noted between groups for time since operation, scar perception, and perception of pain. Using the protocol outlined, there were no differences between the ORIF and CRMMF groups for ranges of motion, occlusion, contour, and motor or sensory function. The ORIF group was associated with perceptible scars. The CRMMF group was associated with chronic pain. CONCLUSIONS: Using a treatment protocol, there were few differences in outcomes between patients treated with CRMMF and ORIF for subcondylar fractures.

A comparison of performance on the OMSITE and ABOMS written qualifying examination. Oral and Maxillofacial Surgery In-Training Examination. American Board of Oral and Maxillofacial Surgery.

PURPOSE: The purpose of this study was to see whether there was a correlation between the performance of persons on the Oral and Maxillofacial Surgery In-Training Examination (OMSITE) and their performance on the American Board of Oral and Maxillofacial Surgery Written Qualifying Examination (ABOMS WQE). METHODS: All OMSITE scores for residents in their last years of training during the years 1992 to 1998 and their scores on the ABOMS WQE were tabulated by American College Testing (ACT) (Iowa City, IA) and submitted for analysis. The data were analyzed using Pearson's correlation coefficients to determine any relationship between the 2 scores. Likelihood ratios were calculated to show the probability of candidates passing the ABOMS WQE based on their OMSITE score. RESULTS: There were 765 scores provided by ACT for the years 1992 to 1998. A significantly positive correlation existed between the OMSITE and ABOMS WQE raw scores for those taking the ABOMS WQE for the first and second times, but not for subsequent attempts. Persons who scored a raw score of over 211 on the OMSITE all passed the ABOMS WQE on their first attempt. Those with a raw score of less than 134 on their OMSITE all failed the ABOMS WQE on their first attempt. CONCLUSION: A highly positive correlation exists between candidate performance on the OMSITE and the ABOMS WQE.

Substitutes for human cadaveric bone in maxillofacial rigid fixation research.

OBJECTIVE: Various materials have been used as human bone substitutes in rigid fixation research. We hypothesize that these substitutes behave differently than human cadaveric bone in maxillofacial research. STUDY DESIGN: Screw insertion torque and pull-out strength of titanium maxillofacial self-tapping bone screws (1.0 mm and 2.4 mm outer diameter) were measured in cadaveric mandible and in the following materials: bovine rib, porcine rib, photoelastic epoxy, red oak, and 2 types of synthetic mandibles. Results were tested for statistically significant differences (unpaired t test, P <.05) in comparison with human bone. RESULTS: For 1.0-mm screws, statistically significant differences were found for the synthetic mandibles groups and oak groups for insertion torque and porcine rib for pull-out strength. For 2.4-mm screws, statistically significant differences were found for the porcine rib and oak groups for insertion torque and the bovine rib and epoxy groups for pull-out strength. CONCLUSION: The results suggest that human bone can be simulated in fixation studies with bone substitute materials.

Maxillofacial injuries in the pediatric patient.

Approximately 22 million children are injured in the United States annually. Children are uniquely susceptible to craniofacial trauma because of their greater cranial-mass-to-body ratio. The pediatric population sustains 1% to 14.7% of all facial fractures. The majority of these injuries are encountered by boys (53.7% - 80%) who are involved in motor vehicle accidents (up to 80.2%). The incidence of other systemic injury concomitant to facial trauma is significant (10.4% - 88%). The management of the pediatric patient with maxillofacial injury should take into consideration the differences in anatomy and physiology between children and adults, the presence of concomitant injury, the particular stage in growth and development (anatomic, physiologic, and psychologic), and the specific injuries and anatomic sites that the injuries affect. This comprehensive review, based on the last 25 years of the world's English-speaking surgical literature, presents current thoughts on the anatomic and physiologic differences between adults and children, a synopsis of childhood growth and development, and an overview of state-of-the-art management of the pediatric patient who has sustained maxillofacial injury.

The relationship between facial fractures and death from neurologic injury.

PURPOSE: The purpose of this study was to review patients who failed to survive blunt trauma and to determine whether there is a relationship between specific facial fracture patterns and death. PATIENTS AND METHODS: This was a retrospective record review of patients with facial fractures admitted to a level I trauma center between January 1, 1993 and December 31, 1996. Records were reviewed for gender, age, injury severity score (ISS), Glasgow Coma Scale (GCS), revised probability of survival (RPS), cause of death, and facial fracture pattern. Facial fracture patterns were grouped as lower face (mandible), midface (maxilla, zygoma, nose, and orbits), and upper face (frontal bone). Causes of death were grouped into neurologic, visceral, combined neurologic and visceral, and other. Surviving and nonsurviving groups were compared. Parametric data were analyzed with a pooled or separate variance t-test, nonparametric data with a Mann-Whitney U-test, and categorical variables with a chi-square test (P < or = .05). The odds ratio with corresponding 95% confidence intervals was used to show the association between facial fracture patterns and death. RESULTS: During the 4-year period, 6,117 patients were admitted with blunt trauma, 661 (11%) of whom had facial fractures. Those who died were more likely to be older than those who survived, with a lower GCS, lower RPS, and higher ISS. Although there was a male predominance in the patient population, there was no gender difference between those who died and those who survived. Surviving patients were more likely to have only isolated mandible injuries. Nonsurvivors were more likely to have isolated midface fractures or combinations of midface and other facial fractures. The odds ratio showed a 13 to 75 times greater risk of patients dying of neurologic injury with patterns other than isolated mandible injury than with any mid- or upper-facial fracture patterns. CONCLUSIONS: Compared with survivors, nonsurviving patients with facial fractures were older and had a lower GCS, higher ISS, and lower RPS. Nonsurviving patients had a dramatic predilection for mid- and upper-facial fracture patterns and death of neurologic injury.

Management of the trochlea of the superior oblique muscle in the repair of orbital roof trauma.

PURPOSE: This study evaluated whether reattachment of the trochlea is necessary to assure normal postoperative extraocular muscle movements after orbital roof exploration and trochlea detachment. PATIENTS AND METHODS: This was a retrospective review of 889 operative records of one surgeon practicing at a level I trauma center between January 1, 1992 and December 31, 1998. Three hundred twenty-four of these cases were trauma related, 97 of which involved the upper facial third or upper midface. From this group, 15 patients required orbital roof exploration with trochlea detachment. Age, gender, cause of injury, form of craniofacial injury, method of repair, materials used, date of first notation of intact extraocular movement, and date of last follow-up were recorded and analyzed. RESULTS: From among the 15 patients requiring orbital roof exploration and repair, 14 (93%) were male, with a mean age of 34.7 +/- 15.2 years. Eight (53%) were involved in motor vehicle accidents, 3 (20%) in motorcycle accidents, and 4 (27%) in high-energy impacts. Most (95%) had injuries that included the frontal sinus, the naso-orbital-ethmoid region (60%), and the orbital rims (60%). After bitemporal flap reflection, careful subperiosteal dissection, supraorbital and supratrochlear nerve repositioning, and trochlea detachment, simple reapproximation of the orbital soft tissues to the reconstructed orbit resulted in satisfactory extraocular muscle movements in all cases. CONCLUSIONS: When careful subperiosteal dissection is used, simple reapproximation of the soft tissues adjacent to the reconstructed orbital roof, without reattachment of the trochlea, is all that was necessary to assure satisfactory extraocular muscle movements postoperatively.

The effect of preoperative ondansetron on the incidence of postoperative nausea and vomiting in patients undergoing outpatient dentoalveolar surgery and general anesthesia.

PURPOSE: The purpose of this investigation was to evaluate the efficacy of ondansetron in controlling postoperative nausea and vomiting (PONV) when used prophylactically in patients undergoing routine dentoalveolar surgery performed under general anesthesia. PATIENT AND METHODS: This was a prospective, double-blind, randomized, placebo-controlled evaluation. Fifty adult ASA I or II patients, requiring routine dentoalveolar surgery performed under general anesthesia, without a prior history of PONV, were randomly assigned to the experimental or control groups. Ondansetron (2.0 mL = 4.0 mg) or normal saline (2.0 mL) were administered intravenously before surgery. Age, gender, type of surgery, duration of surgery, anesthetic dosages, and PONV were evaluated. PONV was evaluated at time 0 (end of anesthesia) and at 30 and 60 minutes postoperatively. Nausea was evaluated using a visual analog scale (1, not nauseous; 5, about to vomit). Vomiting was assessed as a yes or no response. At 20 to 28 hours postoperatively, PONV was evaluated via a telephone call as a yes or no response, along with the number of episodes of nausea, vomiting, or both. Means and standard deviations were calculated for age, surgery, and anesthetics, and differences were assessed using an independent samples t-test. Differences for gender between the control and experimental groups were tested by a nonparametric chi-squared test. Differences between groups for nausea and vomiting were tested with a continuity correction chi-squared test. Differences were considered significant for a P < .05. RESULTS: No significant differences (P < .05) were found between the PONV groups for gender, duration of procedure, or anesthetic dosages. Statistically significant differences were noted in age and the type of surgical procedures performed. No statistically significant differences (P < .05) were noted between groups for nausea or vomiting. CONCLUSION: Based on the results of this study, PONV occurred in approximately 20% of patients (20% for nausea, 8% for vomiting). With the types of anesthetic agents and techniques used in this investigation, there were no significant differences between ondansetron and placebo for prophylaxis against PONV.

An evaluation of the support provided by common internal orbital reconstruction materials.

PURPOSE: The objectives of this investigation were to assess the weight of the combined internal orbital contents, to evaluate the ability of common internal orbital reconstruction materials to resist loads, and to determine whether these materials provide enough load resistance to support the orbital contents. MATERIALS AND METHODS: The combined exonerated internal orbital contents (globe, fat, extraocular musculature, neurovascular structures, lacrimal apparatus, and musculocutaneous lids) from 16 human orbits were weighed. Five each of 13 different internal orbital reconstruction materials (titanium mesh, bioresorbables, Marlex [CR Bard, Cranston, RI], Medpore [Porex Medical, College Park, GA], Silastic [Dow Coming, Midland, MI], dried calvarium) were evaluated for their ability to resist loads applied by Instron 85.11 mechanical testing device (Canton, MA) when used to reconstruct uniform orbital floor defects in synthetic skulls (Sawbones, Vashon Island, WA). Yield load, yield displacement, maximum load, and displacement at maximum load were measured. A comparison was then made between orbital content weight and the load-resisting capabilities of the various materials. RESULTS: The weight of the combined internal orbital contents was 42.97+/-4.05 g (range, 37.80 to 51.03 g). All of the materials tested except Marlex mesh met or exceeded the requirements for support of the combined internal orbital contents. CONCLUSION: Except in the instance of complete loss of the orbital floor, all of the materials tested should provide adequate orbital support.

An in vitro comparison of the effect of number and pattern of positional screws on load resistance.

OBJECTIVE: The purpose of this in vitro investigation was to determine whether the number or pattern of placement of positional screws affected their ability to resist vertical loads resembling mastication. MATERIALS AND METHODS: Standardized bone substitutes were secured with varying numbers of 17.0-mm-long, 2.0-mm outer diameter, self-tapping titanium screws (W. Lorenz Surgical, Jacksonville, FL) in various patterns using a positional screw technique. These patterns included one, two, three, four, and five screws in a linear pattern; two screws in a vertical pattern; three screws in an L-pattern, inverted-L pattern, backward-L pattern, inverted-backward-L pattern, and right and left diagonal pattern; four screws in a box pattern; and five screws in a domino pattern. Five models of each group were fabricated along with a control group. The models were secured in a jig and subjected to vertical loads by an Instron 8511.20 Mechanical Testing Unit (Canton, MA) until failure. Common engineering standards, including yield load, yield displacement, stiffness, maximum load, and displacement at maximum load, were measured, and means and standard deviations were derived and compared for statistical significance with an analysis of variance (ANOVA) and Scheffe multiple comparison test. RESULTS: Screw number and pattern of placement affected the mechanical characteristics in resistance to vertical load. Screw numbers less than three and all linear patterns were the least effective. The three-screw L patterns, as a category, provided greater resistance to vertical loads than either the three-screw linear or three-screw diagonal patterns. The addition of more than three screws in geometric patterns offered no greater benefit than the three-screw L patterns. CONCLUSIONS: In this in vitro study, the three-screw L patterns were the most effective and efficient when using the positional screw technique.

A prospective evaluation of the value of preoperative laboratory testing for office anesthesia and sedation.

PURPOSE: The purpose of this investigation was to determine whether routine laboratory testing affected the clinician's preoperative evaluation and decision-making process for patients undergoing general anesthesia or intravenous sedation in the oral and maxillofacial surgery office. PATIENTS AND METHODS: This was a prospective evaluation of the records of 458 who required an office general anesthetic or intravenous sedation for routine dentoalveolar surgery. The patients ranged in age from 15 to 54 years and were categorized as American Society of Anesthesiologists Classification I or II. Fifty-two percent were female. All patients underwent a history and physical examination, complete blood cell count, and urine analysis. Female patients were tested for pregnancy by measuring the serum beta human chorionic gonadotropin level. All patients older than 40 years of age were further evaluated by posterior-anterior and lateral chest radiographs, as well as electrocardiography. On the day of surgery, the data were reviewed and analyzed, and specific components of the history were reassessed. The results of the decision-making process were evaluated by one investigator. RESULTS: From the 458 patients initially enrolled, 78 failed to return on the appointed day. Of the 235 patients requiring general anesthesia who did return on the appointed day, five had aberrant laboratory values (2%). These consisted of one patient with a low hematocrit, one with a low red blood cell count, one with a low white blood cell count, and two with a urine analysis positive for blood. No procedure was canceled based on the aberrant data. Of the 145 patients requiring intravenous sedation who did return on the appointed day, six had aberrant laboratory values (4%). Two patients exhibited elevated white blood cell counts, two possessed low red blood cell counts, one known to have diabetes had an elevated urine glucose, and one patient with an elevated human chorionic gonadotropin level realized that her menstrual cycle was delayed. The latter two patients had their procedures deferred. CONCLUSIONS: Based on the results of this study, a good history and physical examination and then reassessment of key portions of the history were the major factors in the development of the anesthetic treatment plan. Laboratory data had little if any effect on the decision-making process.

An in vitro evaluation of distractors used for osteogenesis.

OBJECTIVE: The objective of this investigation was to evaluate and compare the mechanical behaviors of distractors used for osteogenesis under various conditions by means of common engineering standards. STUDY DESIGN: Five groups of 5 synthetic mandibles were used in this study (N = 25). The first portion of the investigation compared mandibles without intervention (group A [controls]; n = 5), mandibles that had uniform osteotomies stabilized with an external distractor (group B; n = 5), and mandibles that had simulated sagittal osteotomies rigidly fixated with 3 positional screws (group C; n = 5). The second portion of the investigation compared uniform osteotomies (group B; n = 5) and uniform corticotomies (group D; n = 5) that were stabilized with the same external distractor. The last portion of the investigation compared osteotomies stabilized with an external distractor (group B; n = 5) and osteotomies stabilized with an internal distractor (group E; n = 5). Each construct was subjected to vertical loads on a mechanical testing unit. Common engineering standards, including yield load, yield displacement, maximum load, displacement at maximum load, and stiffness, were measured, recorded, and compared by means of a 1-way analysis of variance and a Scheffé multiple comparison test or independent-samples t test. The means between groups were considered significant for P < .05. A polynomial best-fit curve was calculated for the load/displacement data for each group. RESULTS: During the first portion of the investigation, no significant differences were noted between the control, rigidly fixated sagittal osteotomy, and external distractor with osteotomy groups for displacement at maximum load (P = .19). Significant differences were noted between groups for yield displacement (P = .009), yield load (P < .001), maximum load (P < .001), and stiffness (P < .007). Failures occurred in the control and rigidly fixated groups with fractures of the synthetic mandibles. Failures occurred in the external distractor group with permanent deformation or torsion of the pins. During the second portion of the experiment, no statistically significant differences were noted between the corticotomy and osteotomy groups in stiffness (P = .363), maximum load (P = .207), or yield displacement (P = .940). Statistically significant differences were noted between groups for yield load (P = .036) and displacement at maximum load (P = .010). Failures occurred in both groups with permanent deformation or torsion of the pins. During the last portion of the investigation, statistically significant differences were noted between the external distractor and internal distractor groups in yield load (P < .001), yield displacement (P < .001), maximum load (P = .001), and displacement at maximum load (P = .01); no significant differences were noted in stiffness (P = .71). Failures occurred in the external distractor group with permanent deformation or torsion of the pins. Failures occurred in the internal distractor group with fracture of the model or displacement beyond 30.0 mm. CONCLUSIONS: Different patterns of mechanical behavior were found between the control and rigidly fixated sagittal osteotomy groups and the external distractor group, between the corticotomy and osteotomy groups, and between the internal and external distractor groups.

An experimental evaluation of traumatic globe rupture.

PURPOSE: The purpose of this investigation was to evaluate the surgeon's ability to assess various types of globe injury, to determine the force necessary to rupture the globe with these types of injuries, and to determine typical orbital retraction forces used in the clinical setting. MATERIALS AND METHODS: Forty-four enucleated globes from recently killed cows were divided into four equal groups-one uninjured control group, one group with a through-and-through scleral laceration, another group with a subtotal scleral laceration, and the last group with an 18-gauge needle perforation. Twenty-seven boarded or board eligible oral and maxillofacial surgeons were asked to assess one sample from each of the four groups. They were then asked to retract a simulated globe on a custom-fabricated jig to determine clinical retraction forces. Ten globes from each of the four groups were then subjected to forces until rupture on an Instron 8501M mechanical testing unit. Accuracy of the clinical assessment was determined, and means and standard deviations of the retraction forces and globe rupture forces were derived. RESULTS: Through-and-through lacerations were assessed by surgeons with 100% accuracy, subtotal lacerations with 96% accuracy, uninjured globes with 74% accuracy, and perforated globes with 15% accuracy. Globe rupture occurred at 16.72+/-7.87 kg in the control group, 20.36+/-7.87 kg in the perforated group, 15.38+/-6.06 kg in the subtotal laceration group, and 4.94+/-2.56 kg in the through-and-through laceration group. Statistically significant differences (P < .001) were noted between the total laceration group and all other groups. The mean retraction force was 0.35+/-0.47 kg, which was statistically less than the force used in all of the rupture groups (P < .001). CONCLUSIONS: Severe injuries (through-and-through lacerations) were assessed with 100% accuracy by the clinicians, and less severe injuries with less accuracy. Rupture forces for globes with perforations and subtotal lacerations were no different than for the control group, but substantially less than for the total laceration group. The simulated clinical retraction forces were substantially more than the rupture forces in all of the groups, including the through-and-through laceration group.

An experimental investigation of the safe distance for internal orbital dissection.

PURPOSE: The purpose of this investigation was to determine the distance from the orbital rim to the important soft tissues of the orbital apex using eight reference points to provide clinically useful information for surgical decision making. MATERIALS AND METHODS: Eight human cadavers were used in this investigation. After circumorbital incisions were made and the canthal ligaments were detached, a careful subperiosteal dissection was performed to the soft tissues of the orbital apex. Four reference lines were established. The first two were based on a horizontal line drawn through the medial and lateral canthal ligaments and a perpendicular to this through the infraorbital foramen. The other two were created at points 45 degrees from the first two. Depth measurements were made with a straight probe at the eight points where the lines crossed the orbital rim. Means, standard deviations, and ranges were derived, and statistical differences were calculated between right and left orbits using a paired-samples t-test. Because no right and left differences were noted (P < .05), the data were pooled. RESULTS: The mean distance from the orbital rim to the soft tissues of the orbital apex was 44.1 +/- 1.4 mm medially, 38.3 +/- 3.0 mm laterally, 44.5 +/- 1.72 superiorly, and 39.4 +/- 2.9 mm inferiorly. The superomedial distance was 46.3 +/- 2.7 mm, the inferomedial distance was 44.1 +/- 1.4 mm, the inferolateral distance was 41.4 +/- 2.5 mm, and superolateral distance was 39.4 +/- 2.8 mm. CONCLUSIONS: The distances from the orbital rim to the soft tissues of the orbital apex varied among the eight different reference points (range, 38.3 +/- 3.0 mm to 46.3 +/- 2.7 mm). No distance was less than 31.0 mm or exceeded 51.1 mm. There was no difference noted (P < .05) between the right and left sides for each of the corresponding reference points.

Diagnosis and management of blunt carotid artery injury in oral and maxillofacial surgery.

PURPOSE: Traumatic occlusion of the internal carotid artery (ICA) is a rare complication of maxillofacial trauma or surgery. This investigation evaluated patient demographics, diagnostic methods, and effective therapeutic modalities associated with blunt carotid injury (BCI). PATIENTS AND METHODS: This was a retrospective analysis of patient records with an ICD-9-CM diagnosis of carotid injury conducted at MetroHealth Medical Center during the 24-month period between August 1993 and July 1995. Carotid injuries attributable to penetrating trauma were excluded. Age, gender, cause of injury, Glasgow Coma Scale score, Injury Severity Score, type and location of injury, concomitant injury, diagnostic methods, treatment modalities, and outcome were identified, recorded, and analyzed. RESULTS: During the 24-month period, 12 patients (seven males and five females) suffered BCI. These patients were divided into two groups based on cause of the problem. In group I, there were 3,214 blunt trauma patients admitted during the 2-year study, of which 10 patients had BCI, representing 0.31% of blunt trauma patients, and 1.2% of patients with head injuries. Seven patients presented with hemiplegia, two with cranial nerve palsy, and one with perceptual neglect. Ninety percent of the patients had associated injuries. Two patients had surgical intervention, three received anticoagulation, and five had only supportive care. Four of the 10 patients died, four had moderate neurologic deficits, and two survived with only minor neurologic deficits. In group II, two patients developed BCI after surgery. A 52-year-old woman had a carotid injury after right total temporomandibular joint replacement, and a 48-year-old man who underwent surgical removal of a third molar became hemiplegic postoperatively. The first patient recovered after anticoagulation, whereas the second patient, who received only supportive care, has severe neurologic deficits. CONCLUSIONS: BCI is an uncommon entity. It is usually recognized when a patient develops an unexplained neurologic deficit, most often hemiplegia, subsequent to trauma or surgery of the head, face, or neck. In the early stages, the diagnosis can be missed by carotid ultrasound or computed tomography. The injury is unrelated to Glasgow Coma Scale score. Symptoms may not develop for days after injury in 50% of patients. Anticoagulation appears to be the most beneficial therapeutic modality.