Does the Retromolar Area Provide Adequate Space for an Oral Endotracheal Tube Without Interfering With Intermaxillary Fixation?

PURPOSE: Traumatic maxillofacial injuries requiring intermaxillary fixation (IMF) traditionally necessitate airway management via tracheostomy or submental intubation. The aim of this study is to understand whether the retromolar space can accommodate passage of a reinforced endotracheal tube (ETT) without interfering with establishing IMF, a technique previously described as retromolar intubation. METHODS: A retrospective cross-sectional study was created including previously treated facial trauma patients by our department as the study sample. From this group, 3D reconstructed scans were created and used to estimate that dimensions of the retromolar space. The averages of these dimensions were calculated and compared to the area occupied by different sized reinforced ETTs (6.0, 6.5, 7.0, 7.5, 8.0). A 1-sample t-test was used to compare the retromolar areas to each ETT size for all patients and by gender. RESULTS: Forty-one patients, ages 19-69 years old, treated from July 2010 to November 2018 were included in this study. This included 24 males (21-69yo) and 17 females (19-60yo), with a total of 80 characteristics measured. The retromolar areas calculated were statistically bigger than the reinforced ETT sizes 6.0, 6.5, and 7.0 compared to the average retromolar space area, but not statistically significant for reinforced oral ETT sizes 7.5 and 8.0. CONCLUSION: Our study results suggest the use of 6.0, 6.5 and 7.0 reinforced ETTs can be positioned in the retromolar space, allowing the surgeon to place a patient in IMF without occlusal interference. This technique could provide an alternative option to submental intubation or tracheostomy.

Utilization of Virtual Surgical Planning for Surgical Splint-Assisted Comminuted Maxillomandibular Fracture Reduction and/or Fixation.

STUDY DESIGN: This article was a technical note. OBJECTIVE: To demonstrate the utilization of virtual surgical planning for surgical splint (VSPSS) fabrication. The VSPSS was used as an intraoperative assisting and guiding tool for reduction and/or fixation of treatment of comminuted maxillomandibular fractures. METHODS: The presented technical note showed the fabrication process that began with data acquisition and presurgical planning using virtual surgical planning (VSP). The VSPSS was designed and fabricated after the fractures were reduced digitally in VSP. In the operating room, the VSPSS was seated to guide reduction and/or allow satisfactory fixation in three different situations. RESULTS: Postoperative radiographs showed an acceptable reduction of the fractures. All patients had stable and repeatable occlusion postoperatively. CONCLUSIONS: The VSPSS is a feasible tool for surgeons to assist in the comminuted maxillomandibular fracture management, decrease operating time, and improve fracture stability.

Managing Bone Grafts for the Mandible.

Bone grafting has become an integral part of implant dentistry. To achieve a predictable long-term outcome for osseointegrated implants, a sufficient volume and quality of alveolar bone must be present at implant recipient sites. Resorption of the alveolar ridge and postsurgical or post-traumatic defects of the residual alveolar bone can prevent ideal placement of a dental implant. Thus, in many cases, alveolar bone grafting is the real challenge in implant reconstruction. This article will discuss the various techniques and graft materials for alveolar ridge reconstruction of the mandible. It also compares and contrasts these techniques by reviewing the current literature.

Integrity of Human Mandibular Angle After Block Graft Harvest from Mandibular Body.

PURPOSE: To examine human mandibular angle integrity alterations accompanying a mandibular body block graft harvest surgical procedure. MATERIALS AND METHODS: Hemimandibles from 24 human cadavers were resected and sorted into one of three groups by residual dental status. The height of each hemimandible body was obtained and recorded. Acrylic bone cement was utilized to mount the hemimandibles at the mandibular condyle. Using standard surgical instruments and techniques, cortical bone of the mandibular body buccal plate was resected from the right hemimandibles. Left hemimandibles were used as a control. Each hemimandible was secured in an Instron 5565 mechanical unit. With forces placed on and perpendicular to the occlusal plane, each hemimandible underwent sequential loading until osseous fracture occurred. Descriptive statistics between grouped data were compared and discussed in terms of mean, minimum, and maximum. The statistical relationship between the maximal load, gender, and mandibular body height were identified. RESULTS: Donor and control hemimandible maximal load mean values were 423.63 N and 957.90 N, respectively. A statistically significant difference was present between maximal loads of donor and control hemimandibles (P < .0001). Correlations of statistical significance were present between mandibular bone height and maximal load in the control hemimandibles (P = .009). Correlations of statistical significance were not found between mandibular bone height, displacement at maximal load, and maximal load in the grafted hemimandibles (P >.05). No statistically significant correlation between dental status and gender was found in the donor and control hemimandibles (P > .05). CONCLUSION: After subjected to a typical block graft harvest surgical procedure, the human mandible's integrity is significantly altered. Gender, dental status, and mandibular bone height do not correlate with maximal load,and thus integrity, of donor and control mandibles.

Integrity of a Single Superior Border Plate Repair in Mandibular Angle Fracture: A Novel Cadaveric Human Mandible Model.

PURPOSE: The purpose of this study was to compare the integrity of human mandibular angle fracture after fixation with a single titanium plate along the upper lateral border with that of the native human mandible. MATERIALS AND METHODS: This cross-sectional anatomic study involved the left hemimandibles of 16 human cadavers. They were selected and divided in 2 groups by remaining dental status. Additional predictor variables, such as height of the left mandibular body and gender, were noted. Left hemisected native mandibles were mounted at the condyle and loaded on an Instron 5565 mechanical unit (Instron Corp, Norwood, MA) until fracture. Fractured left hemimandibles were fixated with a titanium miniplate and screws. After plate fixation, each hemimandible was reloaded on an Instron 5565 until fracture. Data pertaining to primary outcomes of load application were recorded in newtons at displacement values of 3.0, 5.0, and 7.0 mm and at displacement at fixation failure. Primary outcomes of maximum load and displacement at maximum load were recorded in newtons and millimeters, respectively. Descriptive statistics were used to summarize sample characteristics. Statistical comparisons were performed using t test, χ2 (or Fisher exact) test, and linear regression. Pearson correlation was used to examine relations between select biomechanical measurements. RESULTS: The study sample was composed of 12 female and 4 male cadaveric hemimandibles. Donors' age at time of death ranged from 54 to 95 years (mean age, 78.94 yr). The mean maximum load in native and plated hemimandibles was 943.56 and 292.57 N, respectively (P < .0001). CONCLUSION: Key clinical findings of this study include the inability of single plate mandible fixation to restore the mandible to preinjury levels and verification that gender, dental status, and height of the mandible do not alter the stability of a single plate fixated mandible.

Surgical Management and Evaluation of the Craniofacial Growth and Morphology in Cleidocranial Dysplasia.

Cleidocranial dysplasia (CCD, MIM 119600) is a rare autosomal dominant disorder affecting bone, cartilage, craniofacial growth, and tooth formation leading to supernumerary teeth. Few reports delineate the genotype-phenotype correlations related to the variations in craniofacial morphology and patterning of the dentition and the complexity of treating patient's malocclusion. Successful management of the craniofacial deformities in patients with CCD requires a multidisciplinary team of healthcare specialists. Approximately 70% of patients are due to point mutations in RUNX2 and <20% due to copy number variations with the remainder unidentified. There is no literature to date, describing the orthognathic management of CCD patients with deletion in one of the RUNX2 alleles. The purpose of this study was to evaluate the craniofacial morphology and dental patterning in a 14-year-old Caucasian female with CCD resulting from a novel microdeletion of RUNX2 in 1 allele. The CCD patient with RUNX2 haploinsufficiency due to microdeletion had decreased craniofacial bone and ankyloses in the permanent dentition. An altered extraction protocol of supernumerary teeth was followed in this patient. Craniofacial growth and morphologic analysis demonstrated atypical skull shape, persistent metopic suture, and decreased mandibular size.

Clinical Anatomy of the Lingual Nerve: A Review.

PURPOSE: Knowledge of lingual nerve anatomy is of paramount importance to dental practitioners and maxillofacial surgeons. The purpose of this article is to review lingual nerve anatomy from the cranial base to its insertion in the tongue and provide a more detailed explanation of its course to prevent procedural nerve injuries. MATERIALS AND METHODS: Fifteen human cadavers from the University of Alabama at Birmingham School of Medicine's Anatomical Donor Program were reviewed. The anatomic structures and landmarks were identified and confirmed by anatomists. Lingual nerve dissection was carried out and reviewed on 15 halved human cadaver skulls (total specimens, 28). RESULTS: Cadaveric dissection provides a detailed examination of the lingual nerve from the cranial base to tongue insertion. The lingual nerve receives the chorda tympani nerve approximately 1 cm below the bifurcation of the lingual and inferior alveolar nerves. The pathway of the lingual nerve is in contact with the periosteum of the mandible just behind the internal oblique ridge. The lingual nerve crosses the submandibular duct at the interproximal space between the mandibular first and second molars. The submandibular ganglion is suspended from the lingual nerve at the distal area of the second mandibular molar. CONCLUSION: A zoning classification is another way to more accurately describe the lingual nerve based on close anatomic landmarks as seen in human cadaveric specimens. This system could identify particular areas of interest that might be at greater procedural risk.

Lingual Nerve Measurements in Cadaveric Dissections: Clinical Applications.

PURPOSE: Lingual nerve (LN) injury is quite prevalent despite its long-known anatomic course. The purpose of this study was to accurately predict the LN pathway by identifying and measuring close anatomic landmarks; these measurements should help lessen the incidence of LN injury. MATERIALS AND METHODS: LN dissection was carried out on 15 halved cadaver skulls (total, 28 specimens). RESULTS: On average, the LN position was approximately 7 mm below the alveolar crest at the distal end of the mandibular second molar, 5.5 mm anterior to the lingula, and 14.6 mm distal to the alveolar crest at the mandibular second molar. From the base of the skull, the LN traveled 5 mm anteriorly to the inferior alveolar nerve and inferiorly to the posterior attachment of the mylohyoid muscle (approximately 1.5 cm distal to the mandibular second molar), where it turned anteromedially and traveled 7 mm inferiorly to the alveolar crest at the mandibular second molar. CONCLUSION: Given the multiple procedures by dental practitioners and maxillofacial surgeons, the LN is at high risk for injury. This study validates the proximity of the LN to anatomic structures commonly encountered during head and neck procedures.

Assessment of Surgical Effects on Patients with Obstructive Sleep Apnea Syndrome Using Computational Fluid Dynamics Simulations.

Obstructive sleep apnea syndrome is one of the most common sleep disorders. To treat patients with this health problem, it is important to detect the severity of this syndrome and occlusion sites in each patient. The goal of this study is to test the hypothesis that the cure of obstructive sleep apnea syndrome by maxillomandibular advancement surgery can be predicted by analyzing the effect of anatomical airway changes on the pressure effort required for normal breathing using a high-fidelity, 3-D numerical model. The employed numerical model consists of: 1) 3-D upper airway geometry construction from patient-specific computed tomographic scans using an image segmentation technique, 2) mixed-element mesh generation of the numerically constructed airway geometry for discretizing the domain of interest, and 3) computational fluid dynamics simulations for predicting the flow field within the airway and the degree of severity of breathing obstruction. In the present study, both laminar and turbulent flow simulations were performed to predict the flow field in the upper airway of the selected patients before and after maxillomandibular advancement surgery. Patients of different body mass indices were also studied to assess their effects. The numerical results were analyzed to evaluate the pressure gradient along the upper airway. The magnitude of the pressure gradient is regarded as the pressure effort required for breathing, and the extent of reduction of the pressure effort is taken to measure the success of the surgery. The description of the employed numerical model, numerical results from simulations of various patients, and suggestion for future work are detailed in this paper.

Computational fluid dynamic analysis of the posterior airway space after maxillomandibular advancement for obstructive sleep apnea syndrome.

PURPOSE: This study evaluated the soft tissue change of the upper airway after maxillomandibular advancement (MMA) using computational fluid dynamics. MATERIALS AND METHODS: Eight patients with obstructive sleep apnea syndrome who required MMA were recruited into this study. All participants underwent pre- and postoperative computed tomography and then MMA by a single oral and maxillofacial surgeon. Upper airway computed tomographic datasets for these 8 patients were created with high-fidelity 3-dimensional numerical models for computational fluid dynamics. The 3-dimensional models were simulated and analyzed to study how changes in airway anatomy affect the pressure effort required for normal breathing. Airway dimensions, skeletal changes, apnea-hypopnea index, and pressure effort of pre- and postoperative 3-dimensional models were compared and correlations were interpreted. RESULTS: After MMA, laminar and turbulent air flows were significantly decreased at every level of the airway. The cross-sectional areas at the soft palate and tongue base were significantly increased. CONCLUSIONS: This study showed that MMA increased airway dimensions by increasing the distance from the occipital base to the pogonion. An increase of this distance showed a significant correlation with an improvement in the apnea-hypopnea index and a decreased pressure effort of the upper airway. Decreasing the pressure effort will decrease the breathing workload. This improves the condition of obstructive sleep apnea syndrome.

Reconstruction of the scalp, calvarium, and frontal sinus.

Scalp and cranial deformities are common after trauma or ablative surgery. Local flaps and free flaps may be used in reconstruction of soft tissue defects, and autogenous bone or alloplastic bone substitutes may be used for cranioplasty procedures. Injuries to the frontal sinus, particularly when complicated by leak of cerebrospinal fluid or obstruction of the nasofrontal outflow tract, represent special challenges. Further studies are recommended to improve the multidisciplinary management of these complex, debilitating conditions, in anticipation of enhanced function and cosmesis, reduced donor site morbidity, and improved surgical outcomes.

Anatomic considerations for posterior iliac crest bone procurement.

PURPOSE: The aim of this study was to identify the relative anatomic locations of relevant vital structures at risk for injury during posterior iliac crest bone graft procurement. MATERIALS AND METHODS: Twenty-one cadavers yielded 39 intact posterior ilia for dissection. The posterior superior iliac spine (PSIS) was used as the primary reference landmark. Measurements were made to the medial branch of the superior cluneal nerves, the superior branch of the middle cluneal nerves, the sciatic notch, and the superior gluteal vessels. Distances from the spinal midline to the superior cluneal nerves were recorded. RESULTS: The average distances from the PSIS to the superior and middle cluneal nerves, greater sciatic notch, and superior gluteal vessels were 5.7 cm (standard deviation, 1.22 cm), 6.55 cm (standard deviation, 1.53 cm), 5.3 cm (standard deviation, 0.71 cm), and 5.4 cm (standard deviation, 0.95 cm), respectively. The most medial superior cluneal nerve was identified at 3.0 to 4.9 cm from the PSIS in 23% of cases, at 5.0 to 6.9 cm from the PSIS in 61.5% of cases, and farther than 7.0 cm from the PSIS in 15.4% of cases. CONCLUSIONS: This study illustrates that the most medial superior cluneal nerve is often closer to the PSIS than previously described and the same holds true for the greater sciatic notch and superior gluteal vessels. Knowledge of the anatomic locations of these important structures should allow the surgeon to avoid or decrease the complication rate of bone procurement from the posterior ilium.

Patient-Specific Geometry Modeling and Mesh Generation for Simulating Obstructive Sleep Apnea Syndrome Cases by Maxillomandibular Advancement.

The objective of this paper is the reconstruction of upper airway geometric models as hybrid meshes from clinically used Computed Tomography (CT) data sets in order to understand the dynamics and behaviors of the pre- and postoperative upper airway systems of Obstructive Sleep Apnea Syndrome (OSAS) patients by viscous Computational Fluid Dynamics (CFD) simulations. The selection criteria for OSAS cases studied are discussed because two reasonable pre- and postoperative upper airway models for CFD simulations may not be created for every case without a special protocol for CT scanning. The geometry extraction and manipulation methods are presented with technical barriers that must be overcome so that they can be used along with computational simulation software as a daily clinical evaluation tool. Eight cases are presented in this paper, and each case consists of pre- and postoperative configurations. The results of computational simulations of two cases are included in this paper as demonstration.

Continuous infusion of bupivacaine for pain control after anterior iliac crest bone grafting for alveolar cleft repair in children.

OBJECTIVE: The purpose of this study was (1) to evaluate the analgesic efficacy of continuous infusion bupivacaine, (2) to evaluate the effects of the site-specific catheter infusion on operating room time, narcotic use, ambulatory status, and length of hospitalization, (3) to monitor for adverse outcomes, and (4) to assess patient/family acceptance. DESIGN: Randomized, double-blinded, and prospective study of bupivacaine versus saline for pain control after anterior iliac crest bone grafting for alveolar cleft repair. SETTING: University of Alabama at Birmingham. PATIENTS: A total of 65 pediatric patients with alveolar cleft defects treated between 2006 and 2009. INTERVENTIONS: Anterior iliac crest bone grafting for alveolar cleft repair with assignment to either a bupivacaine or a saline infusion group. MAIN OUTCOME MEASURES: Physical examination, pain ratings, narcotic use, ambulatory status, operating room time, and length of hospital stay. RESULTS: On the blinded physical exam, 71% in the bupivacaine infusion group and 42% in the saline infusion group were assessed as not experiencing pain at the surgical hip site. The experimental group used less narcotics compared with the control group. No significant differences were noted with operating room time, initial ambulatory status, or length of hospitalization (1.09 versus 1.12 days). Satisfaction and acceptance of the catheter treatment was universal. CONCLUSIONS: These results suggest that postoperative infusion of bupivacaine may be efficacious for enhancing pain relief after bone harvest in pediatric patients and may enhance parental perceptions of postoperative care; however, this patient population is difficult to study accurately.

Bone graft harvesting from regional sites.

Bone grafts are widely used in the reconstruction of osseous defects in the oral and maxillofacial region. Successful osseointegration of dental implants requires sufficient bone surrounding the implant. Although bone substitutes and augmentation techniques offer viable prognoses for achieving the required amount of hard tissue augmentation, autologous bone is the gold standard with regard to quantity, quality, and an uneventful healing. Autogenous bone grafts are generally obtained from the ilium, the rib, and the calvarium. Alternative sources for local harvesting in the mandible can be evaluated by careful clinical and radiographic examinations of the patient. This article discusses the various sources of grafts and the techniques used to harvest bone.