Sexual dimorphisms in three-dimensional masticatory muscle attachment morphometry regulates temporomandibular joint mechanics.

Temporomandibular joint (TMJ) disorders disproportionally affect females, with female to male prevalence varying from 3:1 to 8:1. Sexual dimorphisms in masticatory muscle attachment morphometry and association with craniofacial size, critical for understanding sex-differences in TMJ function, have not been reported. The objective of this study was to determine sex-specific differences in three-dimensional (3D) TMJ muscle attachment morphometry and craniofacial sizes and their impact on TMJ mechanics. Human cadaveric TMJ muscle attachment morphometry and craniofacial anthropometry (10Males; 11Females) were determined by previously developed 3D digitization and imaging-based methods. Sex-differences in muscle attachment morphometry and craniofacial anthropometry, and their correlation were determined, respectively using multivariate general linear and linear regression statistical models. Subject-specific musculoskeletal models of the mandible were developed to determine effects of sexual dimorphisms in mandibular size and TMJ muscle attachment morphometry on joint loading during static biting. There were significant sex-differences in craniofacial size (p = 0.024) and TMJ muscle attachment morphometry (p < 0.001). TMJ muscle attachment morphometry was significantly correlated with craniofacial size. TMJ contact forces estimated from biomechanical models were significantly, 23% on average (p < 0.001), greater for females compared to those for males when generating the same bite forces. There were significant linear correlations between TMJ contact force and both 3D mandibular length (R2 = 0.48, p < 0.001) and muscle force moment arm ratio (R2 = 0.68, p < 0.001). Sexual dimorphisms in masticatory muscle morphology and craniofacial sizes play critical roles in subject-specific TMJ biomechanics. Sex-specific differences in the TMJ mechanical environment should be further investigated concerning mechanical fatigue of TMJ discs associated with TMJ disorders.

Perineurioma of the Tongue: A Case Report and Review of the Literature.

A perineurioma (PN) is a rare benign peripheral nerve sheath tumor derived from perineurial cells. Based on clinical and pathologic features, PNs can be classified into 2 major subtypes: intraneural PN (IPN) and the more common extraneural PN (EPN). EPNs and IPNs are extremely rare in the oral cavity, and there have been only 38 reported cases (21 EPNs, 17 IPNs). In the present case, a 20-year-old man presented with a painless left dorsal tongue mass. Excisional biopsy examination indicated a diagnosis of EPN based on microscopic examination with immunohistochemical analysis. Twenty-eight months later the patient presented again with concern for a recurrent lesion. Intraoral examination showed a firm nonulcerated left dorsal tongue mass. Re-excision and microscopic examination with immunohistochemical analysis confirmed the diagnosis of an EPN. This report presents an unusual case of EPN that arose in the tongue and potentially recurred, although the possibility of persistence versus true recurrence exists. In addition, the clinicopathologic characteristics of previously reported cases of oral PN are reviewed.

Sub-clinical dose of bone morphogenetic protein-2 does not precipitate rampant, sustained inflammatory response in bone wound healing.

Large bone injuries, defects, and chronic wounds present a major problem for medicine. Several therapeutic strategies are used clinically to precipitate bone including a combination therapy delivering osteoinductive bone morphogenetic protein 2 (rhBMP-2) via an osteoconductive scaffold (absorbable collagen sponge [ACS], i.e., INFUSE). Adverse side effects reportedly associated with rhBMP2 administration include rampant inflammation and clinical failures. Although acute inflammation is necessary for proper healing in bone, inflammatory cascade dysregulation can result in sustained tissue damage and poor healing. We hypothesized that a subclinical dose of rhBMP2 modeled in the murine calvarial defect would not precipitate alterations to inflammatory markers during acute phases of bone wound healing. We utilized the 5 mm critical size calvarial defect in C57BL6 wild-type mice which were subsequently treated with ACS and a subclinical dose of rhBMP2 shown to be optimal for healing. Three and 7-day postoperative time points were used to assess the role that rhBMP-2 plays in modulating inflammation vs. ACS alone by cytokine array and histological interrogation. Data revealed that rhBMP-2 delivery resulted in substantial modulation of several markers associated with inflammation, most of which decreased to levels similar to control by the 7-day time point. Additionally, while rhBMP-2 administration increased macrophage response, this peptide had a little noticeable effect on traditional markers of macrophage polarization (M1-iNOS, M2-Arg1). These results suggest that rhBMP-2 delivered at a lower dose does not precipitate rampant inflammation. Thus, an assessment of dosing for rhBMP-2 therapies may lead to better healing outcomes and less surgical failure.

Effect of Measurement Technique on TMJ Mandibular Condyle and Articular Disc Morphometry: CBCT, MRI, and Physical Measurements.

PURPOSE: Accurate description of the temporomandibular size and shape (morphometry) is critical for clinical diagnosis and surgical planning and the design and development of regenerative scaffolds and prosthetic devices and to model the temporomandibular loading environment. The study objective was to determine the 3-dimensional morphometry of the temporomandibular joint (TMJ) condyle and articular disc using cone-beam computed tomography (CBCT), magnetic resonance imaging (MRI), and physical measurements of the same joints using a repeated measures design and to determine the effect of the measurement technique on temporomandibular size and shape. MATERIALS AND METHODS: Human cadaveric heads underwent a multistep protocol to acquire physiologically meaningful measurements of the condyle and disc. The heads first underwent CBCT scanning, and solid models were automatically generated. The superficial soft tissues were dissected, and intact TMJs were excised and underwent MRI scanning, with solid models generated after manual segmentation. After MRI, the intact joints were dissected, and physical measurements of the condyle and articular disc were performed. The CBCT-based model measurements, MRI-based model measurements, and physical measurements were standardized, and a repeated measures study design was used to determine the effect of the measurement technique on the morphometric parameters. RESULTS: Multivariate general linear mixed effects models showed significant effects for measurement technique for condylar morphometric outcomes (P < .001) and articular disc morphometric outcomes (P < .001). The physical measurements after dissection were larger than either the CBCT-based or MRI-based measurements. Differences in imaging-based morphometric parameters followed a complex relationship between imaging modality resolution and contrast between tissue types. CONCLUSIONS: Physical measurements after dissection are still considered the reference standard. However, owing to their inaccessibility in vivo, understanding how the imaging technique affects the temporomandibular size and shape is critical toward the development of high-fidelity solid models to be used in the design and development of regenerative scaffolds, surgical planning, prosthetic devices, and anatomic investigations.

Three-dimensional temporomandibular joint muscle attachment morphometry and its impacts on musculoskeletal modeling.

In musculoskeletal models of the human temporomandibular joint (TMJ), muscles are typically represented by force vectors that connect approximate muscle origin and insertion centroids (centroid-to-centroid force vectors). This simplification assumes equivalent moment arms and muscle lengths for all fibers within a muscle even with complex geometry and may result in inaccurate estimations of muscle force and joint loading. The objectives of this study were to quantify the three-dimensional (3D) human TMJ muscle attachment morphometry and examine its impact on TMJ mechanics. 3D muscle attachment surfaces of temporalis, masseter, lateral pterygoid, and medial pterygoid muscles of human cadaveric heads were generated by co-registering measured attachment boundaries with underlying skull models created from cone-beam computerized tomography (CBCT) images. A bounding box technique was used to quantify 3D muscle attachment size, shape, location, and orientation. Musculoskeletal models of the mandible were then developed and validated to assess the impact of 3D muscle attachment morphometry on joint loading during jaw maximal open-close. The 3D morphometry revealed that muscle lengths and moment arms of temporalis and masseter muscles varied substantially among muscle fibers. The values calculated from the centroid-to-centroid model were significantly different from those calculated using the 'Distributed model', which considered crucial 3D muscle attachment morphometry. Consequently, joint loading was underestimated by more than 50% in the centroid-to-centroid model. Therefore, it is necessary to consider 3D muscle attachment morphometry, especially for muscles with broad attachments, in TMJ musculoskeletal models to precisely quantify the joint mechanical environment critical for understanding TMJ function and mechanobiology.

Warfarin and Newer Agents: What the Oral Surgeon Needs to Know.

The new direct oral anticoagulants-dabigatran etexilate, rivaroxaban, and apixaban- have predictable pharmacokinetic and pharmacodynamic profiles and are alternatives to warfarin. However, many surgeons are wary of these drugs, as there is limited evidence on how to manage bleeding in patients taking them, and only recently has a specific antidote been developed to reverse their anticoagulant effect. Management of the newer agents requires careful adherence to primary measures of bleeding care, knowledge of their mechanism of action, and familiarity with the unapproved and untested reversal strategies that may be required in patients with life-threatening bleeding.

The indications for third-molar extractions.

BACKGROUND: Defining the indications for third-molar extraction continues to be a topic of controversy. METHODS: The dentist's management of third molars commonly hinges on identifying the presence of symptoms or disease that clearly is attributable to the third molar. Use of a guide that serves as a systematic and unambiguous way to classify third molars has been advocated. RESULTS: Patients' symptoms are designated as present and attributable to the third molar (Sx+) or as absent (Sx-). In addition, clinical or radiographic evidence of disease is evaluated and designated as present (D+) or absent (D-). CONCLUSIONS: Evidence-based clinical data developed from prospective investigations have shown that an asymptomatic third molar does not necessarily reflect the absence of disease. PRACTICAL IMPLICATIONS: Current data are not sufficient to refute or support prophylactic extraction versus active surveillance for the routine management of third molars that are asymptomatic and free of disease (group D). Although decisions regarding third-molar management usually are straightforward, the evidence supporting extraction versus retention of asymptomatic disease-free (group D) third molars is lacking. Active surveillance, a prescribed program of follow-up and reassessment at regular intervals are recommended for retained third molars rather than waiting for the onset of symptoms.

Surgical ophthalmologic examination.

Maxillofacial trauma involving injury to the eye and periorbital structures is not uncommon. Oral and maxillofacial surgeons are frequently called on to assess and operate in and around the orbit; it is thus critical to be proficient around the eye because surgical interventions and even physical examinations can cause injury and loss of vision. This article reviews the systematic and accurate assessment of the eye and adnexal structures in a manner appropriate for the oral and maxillofacial surgeon, with a focus on proper examination technique and a high sensitivity for potentially critical abnormalities. A practical approach to performing and recording a detailed ophthalmologic examination is presented, including the assessment of vision, pupillary function, intraocular pressure, and ocular motility, as well as the slit lamp and direct fundoscopic examinations.

Microsurgical repair of the inferior alveolar nerve: success rate and factors that adversely affect outcome.

PURPOSE: The objectives of this study were to determine the likelihood of regaining functional sensory recovery (FSR) after microsurgical repair of the inferior alveolar nerve (IAN), and which variables significantly affected the outcome of that surgery in a large series of patients. MATERIALS AND METHODS: This was a retrospective cohort study that evaluated all patients who had undergone microsurgical repair of the IAN by 1 of the senior surgeons (R.A.M.) from March 1986 through December 2005. The requirements for inclusion of a patient in the study included the availability of a complete chart record and a final follow-up visit at least 12 months after surgery. All other patients were excluded. The predictor variables were categorized as demographic, etiologic, and operative. The final outcome variable was the level of recovery of sensory function as determined by standardized neurosensory testing at the last postoperative visit of each patient and based on guidelines established by the Medical Research Council Scale. Risk factors for surgical failure to achieve useful sensory function were determined from analysis of descriptive statistics, including patient age, patient gender, etiology of nerve injury, chief sensory complaint (numbness, pain, or both), time from injury to surgical intervention (in months), intraoperative findings, and surgical procedure. Logistic regression methods and associated odds ratios were used to quantify the association between the risk factors and improvement. Receiver operator characteristic curve analysis was used to find the threshold of those variables that significantly affected patient outcome. RESULTS: In total, 167 patients (41 male and 126 female patients; mean age, 38.7 years [range, 15-75 years]) underwent 186 IAN repairs (19 patients sustained bilateral IAN injuries). The mean time from injury until surgery was 10.7 months (range, 0-72 months). Successful recovery from neurosensory dysfunction (FSR, defined by the Medical Research Council Scale as ranging from useful sensory function to complete sensory recovery) was observed in 152 repaired IANs (81.7%). With increasing duration from date of injury to IAN repair, the likelihood of FSR decreased (odds ratio, 0.898; P < .001). The odds of achieving FSR exhibited a linear decline between the date of nerve injury and its repair, with a significant drop in rate of successful outcome (FSR) occurring beginning at 12 months after injury. There was also a significant negative relationship between increasing patient age and improvement (odds ratio, 0.97; P = .015), with a threshold drop of achieving FSR at 51 years of age. The cause of the injury, the operative findings, and the type of operation performed to repair the nerve had no significant effect on the likelihood of the patient regaining FSR. The presence of pain after nerve injury did not affect the likelihood of achieving FSR after repair in a statistically significant manner (P = .08). In those patients who did not have pain as a major complaint before nerve repair, pain did not develop after microneurosurgery. CONCLUSIONS: Microsurgical repair of an IAN injury resulted in successful restoration of an acceptable level of neurosensory function (FSR) in most patients (152 of 186 repairs [81.7%]) in this study. The likelihood of regaining FSR was inversely related to both time between the injury and its repair and increasing patient age, with significant threshold drops at 12 months after nerve injury and at 51 years of age, respectively.

Peripheral nerve response to injury.

Oral and maxillofacial surgeons caring for patients who have sustained a nerve injury to a branch of the peripheral trigeminal nerve must possess a basic understanding of the response of the peripheral nerves to trauma. The series of events that subsequently take place are largely dependent on the injury type and severity. Regeneration of the peripheral nerve is possible in many instances and future manipulation of the regenerative microenvironment will lead to advances in the management of these difficult injuries.

Advances in bioengineered conduits for peripheral nerve regeneration.

Although resorbable NGCs have been developed for peripheral nerve grafting, there has been little published on their use as a material for trigeminal nerve repair. Advances in engineered guidance channels and modifications to the single-lumen conduit with growth-permissive substrates, ECM proteins, neurotrophic factors, and supportive Schwann or stem cells, and anisotropic placement of these within the NGC may translate from animal models to clinical human use in the future. A great deal of research is still needed to optimize the presently available NGCs, and their use in peripheral trigeminal nerve repair and regeneration remains yet to be explored. Bioengineered NGCs and additives remain promising alternatives to autogenous nerve grafting in the future. They can incorporate all of the developing strategies for peripheral nerve regeneration that develop in concert with the ever-increasing understanding of regenerative mechanisms. The use of nanomaterials also may resolve the numerous problems associated with traditional conduit limitations by better mimicking the properties of natural tissues. Since cells directly interact with nanostructured ECM proteins, the biomimetic features of anisotropic-designed nanomaterials coupled with luminal additive ECMs, neurotrophic factors, and Schwann cells may provide for great progress in peripheral nerve regeneration.

The accuracy of virtual surgical planning in free fibula mandibular reconstruction: comparison of planned and final results.

PURPOSE: The concept of virtual surgery uses surgical simulation rather than relying exclusively on intraoperative manual approximation of facial reconstruction. The purpose of this study was to evaluate the degree to which surgical outcomes in free fibula mandibular reconstructions planned with virtual surgery and carried out with prefabricated surgical plate templates and cutting guides correlated to the virtual surgical plan in a series of 11 patients. MATERIALS AND METHODS: This retrospective study evaluated 11 consecutive patients (6 males and 5 females) with an average age of 50.73 years (range, 23-72 years) who required mandibular reconstruction for aggressive benign or malignant disease with a free fibula osseomyocutaneous flap at Emory University Hospital (Atlanta, GA) between January 1, 2009 and December 31, 2009. In each case, a high-resolution helical computed tomography (CT) scan of the maxillofacial region and mandible was obtained prior to surgery. The CT data was sent on a CD to a modeling company (Medical Modeling Inc, Golden, CO). The scans were then converted into 3-dimensional models of the maxillofacial skeleton utilizing both automatic and manual segmentation techniques in the SurgiCase CMF software (Materialise NV, Leuven, Belgium). A virtual surgery planning session was held via a Web meeting between the surgeons and the modeling company, at which the resection planes of the mandible, positioning of the plate, and fibula lengths/osteotomy angles were established. The surgery was then carried out using prefabricated cutting guides and manual bending of a reconstruction plate using a prefabricated plate template. A postoperative CT scan of each patient was obtained within the first 7 postoperative days on the same scanner. Three-dimensional computer models of the final reconstruction were obtained for comparison with the preoperative virtual plan. To make the desired comparisons, the 3-dimensional objects representing the postoperative surgical outcome were superimposed onto the preoperative virtual plan using manual alignment techniques. These objects were then compared by 1-to-1 magnification for measurements of fibular bone volume, location of mandibular osteotomies, location of fibular osteotomies, plate contour, plate position on fibula, and plate position on mandible. Comparison was made between the virtual and final plates with regard to contour and position through superimposition overlays of the 3-dimensional models that are registered in the same coordinate system. RESULTS: A total of 19 mandibular osteotomies were carried out. The mean distance of the actual mandibular osteotomy when compared to the virtual mandibular osteotomy was 2.00 ± 1.12 mm. The mean volume determined by the software program of the 11 virtual fibulas was 13,669.45 ± 3,874.15 mm(3) (range, 9,568 to 22,860 mm(3)), and the mean volume of the 11 actual postoperative fibulas was 12,361.09 ± 4,161.80 mm(3) (range, 7,142 to 22,294 mm(3)). The mean percentage volumes of the actual postoperative fibula compared to the planned fibula were 90.93 ± 18.03%. A total of 22 fibular segments were involved in the study created by 44 separate fibula osteotomies. The mean distance of the actual fibula osteotomy when compared to the virtual fibula osteotomy was 1.30 ± 0.59 mm. The mean percentage overlap of the actual plate to the virtual plate was 58.73% ± 8.96%. CONCLUSIONS: Virtual surgical planning appears to have a positive impact on the reconstruction of major mandibular defects through the provision of accuracy difficult to achieve through manual placement of the graft, even in the hands of experienced surgeons. Although a reasonably high level of accuracy was achieved in the mandibular and fibula osteotomies through use of the surgical cutting guides, the limited ability to correctly contour the plate by hand to replicate the plate template is reflected in our findings.

Microsurgical repair of the peripheral trigeminal nerve after mandibular sagittal split ramus osteotomy.

PURPOSE: Injuries to the inferior alveolar nerve (IAN) and lingual nerves (LNs) have long been known complications of the mandibular sagittal split ramus osteotomy (SSRO). Most postoperative paresthesias resolve without treatment. However, microsurgical exploration of the nerve may be indicated in cases of significant persistent sensory dysfunction associated with observed or suspected localized IAN or LN injury. We report the demographics and outcome of microsurgical exploration and repair of peripheral branches of the trigeminal nerve injured because of the SSRO. MATERIALS AND METHODS: A retrospective chart review was completed on all patients who had microsurgical repair of peripheral trigeminal nerve injuries caused by mandibular SSRO and were operated on by the senior author (R.A.M.) between March 1986 and December 2005. A physical examination, including standardized neurosensory testing (NST) as described by Zuniga et al, was completed on each patient preoperatively. All patients were followed periodically after surgery for at least 1 year with NST repeated at each visit. NST results obtained at the last patient visit were used to determine the final level of recovery of sensory function. Sensory recovery was evaluated using guidelines established by the Medical Research Council scale. The following data were collected and analyzed: age of patient, gender, nerve injured, chief sensory complaint (numbness, pain, or both), duration (months) from injury to surgical intervention, intraoperative findings, surgical procedure, and neurosensory status at final evaluation. Given the retrospective nature of this study, the research was exempt from our institutional review board ethics committee. RESULTS: There were 54 (n = 54) patients (8 males and 46 females) with an average age of 36.9 years (range, 16 to 55 years) and a follow-up of at least 12 months. The most commonly injured/repaired nerve was the IAN (n = 39), followed by the LN (n = 14), and the long buccal nerve (n = 1). In 31 patients (57.4%), the chief sensory complaint was numbness, while 20 patients (37%) complained of pain and numbness, and 3 patients (5.5%) complained of pain without mention of numbness. The average time from nerve injury to repair was 9.4 months (range, 3 to 50 months). The most common intraoperative finding was a discontinuity defect (n = 18, 33.3%), followed by partial nerve severance (n = 15, 27.8%), neuroma-in-continuity (n = 11, 20.3%), and compression injury (n = 10, 18.5%). The most frequent surgical procedure was autogenous nerve graft reconstruction of the IAN using the sural or great auricular nerve (n = 22, 40.7%), followed by excision of a neuroma with or without neurorrhaphy (n = 13, 24.1%). All the LN injuries (n = 14) were partial or complete severances, of which 2 were reconstructed with autogenous nerve grafts and the other 12 underwent neurorrhaphy. The long buccal nerve injury required excision of a proximal stump neuroma without neurorrhaphy. After a minimum of 1-year follow-up, NST showed that 8 nerves (14.8%) showed no sign of recovery; 19 nerves (35.2%) had regained "useful sensory function," and 27 nerves (50%) showed full recovery as described by the Medical Research Council scale. CONCLUSIONS: Microsurgical repair of the IAN or LN injured during the SSRO can be considered in patients with persistent, unacceptable sensory dysfunction in the distribution of the involved nerve. Modifications of surgical technique may be helpful in reducing the incidence of such injuries. Based on our experience, an algorithm for evaluation and treatment is presented.

Retrospective review of microsurgical repair of 222 lingual nerve injuries.

PURPOSE: Injury to the lingual nerve (LN) is a known complication associated with several oral and maxillofacial surgical procedures. We have reviewed the demographics, timing, and outcome of microsurgical repair of the LN. MATERIALS AND METHODS: A retrospective chart review was completed of all patients who had undergone microsurgical repair of the LN by one of us (R.A.M.) from March 1986 through December 2005. A physical examination, including standardized neurosensory testing, was completed of each patient preoperatively. All patients were followed up periodically after surgery for at least 1 year, with neurosensory testing repeated at each visit. Sensory recovery was determined from the patient's final neurosensory testing results and evaluated using the guidelines established by the Medical Research Council Scale. The following data were collected and analyzed: patient age, gender, nerve injury etiology, chief sensory complaint (numbness or pain, or both), interval from injury to surgical intervention, intraoperative findings, surgical procedure, and neurosensory status at the final evaluation. The patients were classified according to whether they achieved "useful sensory recovery" or better, according to the Medical Research Council Scale, or had unsatisfactory or no improvement in sensation. Logistic regression methods and associated odds ratios (OR) were used to quantify the association between the risk factors and improvement. Receiver operating characteristic curve analysis was used to find the age threshold and duration that maximally separated the patient outcomes. RESULTS: A total of 222 patients (51 males and 171 females; average age 31.1 years, range 15 to 61) underwent LN repair and returned for at least 1 year of follow-up. The most common cause of LN injury was mandibular third molar removal (n = 191, 86%), followed by sagittal split mandibular ramus osteotomy (n = 14, 6.3%). Most patients complained preoperatively of numbness (n = 122, 55%) or numbness with pain (n = 94, 42.3%). The average interval from injury to surgery was 8.5 months (range 1.5 to 96). The most commonly performed operation was excision of a proximal stump neuroma with neurorrhaphy (n = 154, 69%), followed by external decompression with internal neurolysis (n = 29, 13%). Nineteen patients (8.6%) underwent an autogenous nerve graft procedure (greater auricular or sural nerve) for reconstruction of a nerve gap. A collagen cuff was placed around the repair site in 8 patients (3.6%; external decompression with internal neurolysis in 2 and neurorrhaphy in 6). Recovery from neurosensory dysfunction (defined by the Medical Research Council Scale as ranging from "useful sensory function" to a "complete return of sensation") was observed in 201 patients (90.5%; 146 patients with complete recovery and 55 patients with recovery to "useful sensory function"), and 21 patients (9.5%) had no or inadequate improvement. Using the logistic regression model, a shorter interval between nerve injury and repair resulted in greater odds of improvement (OR 0.942, P = .0064); with each month that passed, the odds of improvement decreased by 5.8%. The receiver operating characteristic analysis revealed that patients who waited more than 9 months for repair were at a significantly greater risk of nonimprovement. Statistical significance was observed between patient age and outcome (OR 0.945, P = .0067) representing a 5.5% decrease in the chance of recovery for every year of age in patients 45 years old and older. The odds of a return of acceptable neurosensory function were better when the patient's presenting symptom was pain and not numbness (OR 0.04, P < .001). CONCLUSIONS: Microsurgical repair of LN injury has the best chance of successful restoration of acceptable neurosensory function if done within 9 months of the injury. The likelihood of recovery after nerve repair decreased progressively when the repair occurred more than 9 months after injury and with increasing patient age.

Microsurgical repair of peripheral trigeminal nerve injuries from maxillofacial trauma.

PURPOSE: Injuries to the peripheral branches of the trigeminal nerve from maxillofacial trauma can have distressing sensory or functional sequelae. The present study reports the results of trigeminal microneurosurgical repair in a series of patients with maxillofacial trauma. MATERIALS AND METHODS: A retrospective chart review was completed of all patients who had undergone microneurosurgical repair of peripheral trigeminal nerve injuries caused by maxillofacial trauma and who had been treated by one of us (R.A.M.) from March 1986 through December 2005. A physical examination, including standardized neurosensory testing, was completed on each patient preoperatively. All patients were followed up periodically after surgery for at least 1 year with neurosensory testing repeated at each visit. Sensory recovery was evaluated using the guidelines established by the Medical Research Council. The following data were collected and analyzed: patient age, gender, nerve injured, etiology (location of fracture), chief sensory complaint (ie, numbness or pain, or both), interval from injury to surgical intervention, intraoperative findings, surgical procedure, and neurosensory status at the final evaluation. RESULTS: A total of 42 patients (25 males and 17 females) with average age of 37.1 years (range 11 to 61) and a follow-up of at least 12 months were included in the study. The most commonly injured/repaired nerve was the inferior alveolar nerve caused by mandibular angle fracture (n = 21), followed by the mental nerve due to mandibular parasymphysis fracture (n = 12), the infraorbital nerve from zygomaticomaxillary complex fracture (n = 7), and lingual nerve and long buccal nerve from mandibular body fracture (n = 1 each). In 17 patients, the chief sensory complaint was numbness, and 25 patients complained of pain with or without mention of numbness. The average interval from nerve injury to repair was 12.5 months (range 2 to 24). The most common intraoperative finding was a compression injury (n = 19), followed by partial nerve severance (n = 9). The most frequent surgical procedure was external decompression/internal neurolysis (n = 20). Ten injured nerves required reconstruction of a discontinuity defect with an autogenous nerve graft (donor sural or great auricular nerve), all of which were associated with mandibular angle or parasymphysis fractures. After a minimum of 1 year of follow-up, neurosensory testing demonstrated that 6 nerves (14%) showed no sign of recovery, 23 nerves (55%) had regained "useful sensory function," and 13 nerves (31%) showed full recovery as described by the Medical Research Council scale. CONCLUSIONS: Microsurgical repair of peripheral branches of the trigeminal nerve injured by maxillofacial trauma produced significant improvement or complete recovery in 36 (86%) of 42 patients. These results compare favorably with the microsurgical repair of peripheral trigeminal nerve injuries resulting from other causes.