Hans C. Brockhoff

Mandibular Fractures: An Analysis of the Epidemiology and Patterns of Injury in 4,143 Fractures

PURPOSE The objective of this study was to complete a comprehensive retrospective review of the epidemiology and patterns of injury in mandibular trauma based on the Parkland Memorial Hospital trauma database over a 17-year period. The authors identified 4,143 fractures in 2,828 patients from the databank. In mandibular trauma, the mechanism of injury and several other variables can be an important point of differentiation with regard to fracture pattern. By showing the statistical relation between these and fracture pattern, the authors hope to provide surgeons with a better understanding of such a relation. MATERIALS AND METHODS Mandibular fracture data were collected from the Parkland Memorial Hospital trauma registry using International Classification of Diseases, Ninth Revision codes (802.21 to 802.39). Information included fracture type, age, gender, mechanism of injury, and associated injuries. The Parkland Memorial Hospital trauma registry yielded 4,143 mandibular fractures in 2,828 patients managed at Parkland Memorial Hospital from 1993 through 2010. RESULTS Based on retrospective analysis, results were obtained for age, gender, monthly distribution, anatomic distribution, and mechanism of injury. The average age was approximately 38 years, with most patients (33%) in the third decade. An overwhelming majority of patients were men (83.27%), with only 16.27% consisting of women. Most injuries occurred in the summer months, with July being the most common month of occurrence. The mechanism of injury predominantly involved low-velocity blunt injuries (62%) compared with high-velocity blunt injuries (31%). The anatomic distribution of fractures evaluated was the angle (27%), symphysis (21.3%), condyle and subcondyle (18.4%), and body (16.8%). CONCLUSION This study helps provide and support the relation between several variables associated with many common traumatic injuries seen in the mandible. This analysis can be used to help surgeons identify and anticipate injuries based on age, gender, and mechanism of injury.

Course of the mandibular incisive canal and its impact on harvesting symphysis bone grafts.

PURPOSE To characterize the anatomic course of the mandibular incisive canal to define parameters for harvesting autogenous bone from the symphysis of the mandible. MATERIALS AND METHODS A series of osteotomies were completed between the mental foramina in the anterior mandibles of 19 cadavers. Methylene blue dye was used to help identify the incisive canal. From the canal, distances to key adjacent landmarks were measured with a Boley gauge to 0.1 mm. Measurements included distances from the mandibular incisive canal to the buccal cortex, the lingual cortex, the inferior border of the mandible, the apices of the teeth, and the buccal cementoenamel junction (CEJ) of the teeth. RESULTS The canal decreased in diameter from lateral to medial. It tended to be closer to the buccal cortical bone than to the lingual cortex (P < .001) and was, at times, directly abutting the buccal cortex (average distance to buccal cortex, 3.5 mm). The canal maintained a relatively constant distance from the apices of the teeth (approximately 7 to 8 mm), coursing inferiorly under the longer canines bilaterally. The canal became increasingly difficult to identify toward the midline, likely dispersing into microscopic tributaries. CONCLUSIONS The authors suggest several modifications to the standard surgical approach to the symphysis area during the harvest of bone grafts. When the goal is to avoid the mandibular incisive canal, osteotomies should not exceed a depth of 4 mm, should be at least 5 mm anterior to the mental foramen, and 9 mm below the root apices (or 23 mm below the lowest facial CEJ) and should maintain the contour of the mandibles inferior border. Alternatively, some degree of canal compromise can be accepted and larger grafts can be obtained by increasing the depth of the harvest in the horizontal dimension or decreasing the distance from the osteotomy to the root apices (or the CEJ) in the vertical dimension.

Correlating the depth of invasion at specific anatomic locations with the risk for regional metastatic disease to lymph nodes in the neck for oral squamous cell carcinoma

The purpose of this study was to investigate the critical primary tumor depth of invasion in oral squamous cell carcinoma that would lead to a 20% or greater risk of nodal metastasis.

Comparison of intraoral harvest sites in the edentulous versus dentate specimen

OBJECTIVE The aim of this study was to compare the edentulous vs dentate specimen intraoral bone harvest sites. We wished to identify if there were any sites that yielded similar quantities of bone regardless of the status of the dentition. STUDY DESIGN There were 59 cadavers in the study. Three continuous outcomes (area, thickness, and volume) were measured for each cadaver at 4 sites (zygoma, symphysis, ramus, and coronoid). RESULTS Status of the dentition was not a factor in the quantity of harvested bone in regard to surface area and volume. The only difference noted between the dentate and edentulous groups was the thickness in the symphysis and zygomaticomaxillary buttress, with the dentate group, on average, having greater thickness. CONCLUSIONS There appeared to be similar amounts of bone available in dentate and edentulous specimens in our study. This information should encourage clinicians to consider intraoral bone harvest for augmentation of an edentulous ridge regardless of the status of the dentition.

Delayed ear reconstruction: Case report of reconstruction of an avulsed ear 2 days after injury

Auricular reattachment and reconstruction following traumatic ear avulsion is a challenging surgical problem. Suggested reconstruction methods include direct reattachment, composite grafting, pocket methods, coverage with periauricular flaps, and microsurgical repair. A published alternative is reattachment and burial of the amputated part under a postauricular flap. If circumstances delay the surgical intervention, what is a safe window to still consider this form of treatment? In the current report, we present a case of a complete partial ear avulsion, which was reattached in the ER as a free graft. Two days later the cartilage was banked under a postauricular flap. A 22 year-old male had his ear was completely bitten off which was re-attached. Two days later the skin of the avulsed segment was dark and bloodless. The avulsed segment was removed from the ear. The overlying skin was dissected off of the attached ear leaving perichondrium on the medial aspect of the ear. The cartilage was then reattached. A postauricular pocket/flap was created and the ear tucked and secured to the postauricular fascia and skin closed overtop. Five weeks later, the patient had division and inset of the flap with a full thickness skin graft to the posterior aspect of the ear. Our results and experiences suggest that immediate reconstruction may not be crucial.

Anatomic analysis of the conchal bowl cartilage

PURPOSE The conchal bowl is a portion of auricular cartilage commonly used as an autologous graft for various maxillofacial procedures. Few studies have attempted to describe the anatomy of this region in detail, particularly in relation to the curvature of the conchal bowl. The present study has provided detailed information about the anatomy of the auricular cartilage in the conchal bowl region that could assist in the surgical design of graft harvesting. MATERIALS AND METHODS A total of 35 pairs of cadaver ears without gross deformity (15 male, 20 female; aged 39 to 99 years) were dissected to completely expose the cartilage skeleton. Each cartilage was stabilized, and the conchal bowl was mapped. The starting reference point was defined as the intersection of the lateral border of the antihelix and the superiormost aspect of the inferior crux. A prefabricated grid was then used to imprint a 4 × 5 matrix of pinpoint ink spots on the surface of each cartilage, with 6-mm increments between each spot. The grids y and x axes were then aligned with the landmarks above. Next, a MicroScribe 3-dimensional digitizer (ghost3d.com) was used to capture the 3-dimensional coordinates for each point on the ears surface and the coordinates were transferred into an Excel spreadsheet. After digitization, a Boley gauge was used to measure the thickness of the cartilage at each premarked spot. The gathered data points and measurements were examined to describe our parameters of interest (ie, depth, thickness, and curvature). RESULTS The average maximum conchal bowl depth was 10.5 ± 3.0 mm in the female ears and 10.7 ± 2.5 mm in the male ears. In general, the conchal bowl depth at each point did not differ significantly between the males and females. The mean cartilage thickness ranged from 0.77 to 1.79 mm (mean 1.15 ± 0.26) in the females and 0.95 to 1.45 mm (mean 1.25 ± 0.23) in the males. Both genders showed an increase in the conchal bowl depth from inferiorly to superiorly and from posteriorly to anteriorly. The cartilage thickness also increased from posteriorly to anteriorly; however, the exact shape is complex. CONCLUSIONS A detailed understanding of the facial anatomy is important in the practice of facial surgery. The results we have presented will provide surgeons with information on the overall dimensions, thickness, and curvature of the conchal bowl that could allow more advantageous donor site selection.

Tongue and Floor of Mouth Defect Reconstruction

The tongue and floor of the mouth represents an anatomically small compartment within the head and neck, but it is a complex collision of tissue types and function. This area is perhaps often overlooked in the hierarchy of importance due to the concealment of the overlying lips and maxillomandibular complexes, but nonetheless demands the utmost attention to the reconstructive surgeon. There are numerous tissues of distinct embryologic origins that interface with one another. Applying a thorough understanding of the relevant surgical anatomy, reconstructive options, and scientific information can lead to individually tailored approaches which optimize surgical outcomes. The focus of this chapter will be on reconstruction of the tongue and floor of the mouth defects that are compositely less than or equal to a hemiglossectomy. There will be a systematic and straightforward approach that both the neophyte and seasoned surgeon alike can glean from.

Vessel injuries of the head and neck presenting in mandibular fractures.

OBJECTIVE Extracranial vascular injuries of the head and neck are relatively underdiagnosed in patients with acute trauma and can carry devastating sequelae. We wished to identify the correlation between mandibular fractures and injuries to major vessels of the head and neck. STUDY DESIGN A retrospective review of our trauma registry was performed for the 1993-2007 period. The data on all mandibular fractures were collected. RESULTS A total of 2288 patients presented to Parkland Memorial Hospital with mandibular fractures, of whom 47 (2%) had an injury to a major vessel of the neck. Nearly half, 23 (48.9%), were the result of high-velocity penetrating injuries, namely gunshot wounds, whereas 17 (36.2%) were the result of high-velocity blunt motor vehicle or motorcycle collisions. CONCLUSIONS Patients who sustain a mandibular fracture in the setting of a high-velocity mechanism should be approached with the possibility of vascular injury of the great vessels of the neck kept in mind.