Richard H. Haug

Cervical spine fractures and maxillofacial trauma

Cervical spine fractures are a serious complication of maxillofacial trauma because of the high potential for mortality and neurologic morbidity. This study reviewed 563 patients with facial fractures treated by the Division of Oral and Maxillofacial Surgery at a level I trauma center and identified 11 concomitant cervical spine fractures (2.0%). These patients were almost exclusively male (91%), white (100%), between 20 and 35 years of age (64%), involved in a motor vehicle accident (91%), with a concomitant mandibular fracture (91%). The examination, diagnosis, and management of patients with cervical spine injuries are discussed.

Retention of asymptomatic bone plates used for orthognathic surgery and facial fractures

Over the past three decades there has been an improvement in biomaterials that has virtually replaced the use of stainless steel with titanium and its alloys. Based on the possibility of causing corrosion, toxicity, hypersensitivity, and stress protection, stainless steel should not be considered as a permanent implant in maxillofacial fixation. However, because of their superior corrosion resistance, noncarcinogenicity, hyposensitivity, nontoxicity, and excellent tissue compatibility, titanium and Ti-6Al-4V may be retained as permanent implants in maxillofacial fixation. The stress protection offered by such devices, and the possible complications associated with their removal, also support this concept. Finally, the costs incurred in removal do not justify the benefits derived.

An in vitro comparison of the mechanical characteristics of three sagittal ramus osteotomy fixation techniques

PURPOSEnThe purpose of this in vitro investigation was to compare the mechanical characteristics of three techniques for the rigid internal fixation of simulated sagittal ramus osteotomies in terms of their ability to resist vertical loads resembling masticatory forces.nnnMATERIALS AND METHODSnFifteen bovine ribs of similar size and shape were subjected to uniform osteotomies resembling a sagittal ramus osteotomy. They were divided into three groups and fixed with three 2.0-mm bicortical positional screws in an inverted L-pattern, eight monocortical screws and a sagittal strut plate, or a hybrid system using three 2.0-mm bicortical positional screws, five 2.0-mm monocortical screws, and a sagittal strut plate. The repaired ribs were secured in a jig, subjected to vertically deforming forces, and evaluated for yield load, yield point, maximum load, displacement at maximum load, load at 3.0 mm displacement, and stiffness. The various groups were compared statistically with a Scheffe multiple comparison test.nnnRESULTSnNo statistically significant differences existed between the positional screw group and the hybrid group (P > .05). No statistically significant differences were noted in yield displacement, yield load, displacement at maximum load, for any of the groups (P > .05). There were differences noted between the monocortical strut group and other groups in maximum load, load at 3.0 mm displacement, and stiffness (P > .05).nnnCONCLUSIONSnThe monocortically fixed sagittal strut plate offers less resistance to maximum load and loads at 3.0 mm displacement and is less stiff than either a three-positional screw system or a hybrid system. No differences existed between the three positional screw systems and the hybrid system. However, given the low yield loads and yield displacements, these differences may not be clinically important.

Management of facial dog bite injuries

Oral and maxillofacial surgeons are frequently called on to evaluate and treat patients with facial trauma. While vehicular accidents and interpersonal violence are the most frequent causes, an estimated 44,000 facial injuries are encountered annually from dog bites in the United States. ~ With the exception of a few isolated case reports, discussions of these injuries have been virtually nonexistent in the oral and maxillofacial surgery literature. The purpose of this article is to provide the oral and maxillofacial surgeon with a comprehensive review of the incidence, pathophysiology, diagnosis, and management of facial dog bite injuries (FDB1).

An Evaluation of the Support Provided by Common Internal Orbital Reconstruction Materials

PURPOSEnThe 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.nnnMATERIALS AND METHODSnThe 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.nnnRESULTSnThe 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.nnnCONCLUSIONnExcept in the instance of complete loss of the orbital floor, all of the materials tested should provide adequate orbital support.

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

PURPOSEnThe purpose of this investigation was to determine whether routine laboratory testing affected the clinicians preoperative evaluation and decision-making process for patients undergoing general anesthesia or intravenous sedation in the oral and maxillofacial surgery office.nnnPATIENTS AND METHODSnThis 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.nnnRESULTSnFrom 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.nnnCONCLUSIONSnBased 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.

A comparison of mandibular angle fracture plating techniques

OBJECTIVEnThe purpose of this investigation was to compare the conventional technique of mandibular angle fracture plating with two biomechanically dissimilar techniques in their abilities to resist vertical loads similar to masticatory forces.nnnSTUDY DESIGNnThree groups of five synthetic hemimandibles with simulated fracture repairs were compared for their capabilities to resist vertical deformation. The conventional group was stabilized with a thin tension band system at the superior border and thick stabilization plate system at the inferior border. The nontraditional group was stabilized with a thick tension band system at the superior border and thin stabilization plate system at the inferior border. The two miniplate group was stabilized with a thin tension band system at the superior border and thin stabilization plate at the inferior border. A cantilever beam design was used. Testing was performed with an instron 8511.20 (Instron Corp., Canton, Mass.) mechanical testing device. The three groups were compared with a two way analysis of variance.nnnRESULTSnThe forces resisted by the conventional group (167.6 +/- 18.2 N), the nontraditional group (156.3 +/- 33.9 N), and two miniplate group (154.0 +/- 18.4 N) were not statistically different (F = 0.44, p > 0.66). All failures occurred at the tension bands secured with monocortical screws.nnnCONCLUSIONSnUnder the conditions described in this in vitro investigation, plate thickness or pattern made no difference. All failures in this experiment occurred with monocortical screws in the superior border tension band system.

Measurement standards for the prevertebral region in the lateral soft-tissue radiograph of the neck

One hundred thirty-one lateral soft-tissue radiographs of the neck, taken over a 6-month period, were reviewed. Eighty-six radiographs were normal. The mean prevertebral soft-tissue thickness in the posterior-anterior dimension for each normal radiograph was measured. The mean thickness in the retropharyngeal region ranged from 6.2 mm in the infant to 3.7 mm in the adult, while the mean thickness in the retrotracheal region ranged from 9.2 mm in the preschool group to 12.1 mm in the adult.

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

PURPOSEnTraumatic 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).nnnPATIENTS AND METHODSnThis 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.nnnRESULTSnDuring 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.nnnCONCLUSIONSnBCI 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.

An in vitro evaluation of distractors used for osteogenesis

OBJECTIVEnThe 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.nnnSTUDY DESIGNnFive 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.nnnRESULTSnDuring 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.nnnCONCLUSIONSnDifferent 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.