Preventing work-related musculoskeletal injuries among oral and maxillofacial surgeons.

BACKGROUND: Oral and maxillofacial surgeons (OMS) are continually required to adjust position and posture to access the limited surgical field in and around the head and neck, oral cavity, and oropharynx. Very limited data exists that quantifies the burden of musculoskeletal disorders (MSD) among OMS. OBJECTIVE: This exploratory study seeks to address these literature gaps by assessing the prevalence of MSD among OMS. METHOD: A 12-question survey was designed to investigate the prevalence of MSD for OMS, including residents in training, actively practicing surgeons, and retired surgeons. Seventy-six surveys were distributed and completed in person by surgeons attending professional conferences from September 2018-September 2019. Survey questions included the Baker-Wong Faces pain scale, years in practice, number of hours worked per week, job tenure, pain attributable to work, and age. The Nordic scale identified and delineated anatomic site of musculoskeletal complaints, duration and treatment sought. RESULTS: The most frequently cited sources and locations of pain attributable to occupation were shoulders, neck, and lower back. The risk of MSD symptoms was relatively two-fold [PR = 2.54, 95% CI = 0.90, 7.22] among OMS in practice for more than ten years compared to those in practice less than ten years. After adjusting for age and hours worked per week as potential confounders, the risk of MSD symptoms was higher among OMS in practice for more than ten years compared to those with less than ten years of experience, despite no statistically significant association. CONCLUSION: OMS are impacted by a high prevalence of MSD. The neck, shoulder, and lower back are the most frequently affected with discomfort and pain. This study found that practicing oral and maxillofacial surgery for more than 10 years is a potential risk factor for experiencing MSD.

The Role of Dental Occlusion Ties to Achieve Stable Maxillomandibular Fixation During Temporomandibular Joint Replacement.

Dental occlusion ties (Minne Ties®) are a new example of the concept of an oral zip tie used to establish maxillomandibular fixation (MMF). Each tie uses a blunt introducer that is easily passed between embrasures and fed through a self-locking, unidirectional clasp. Five to six ties are used to establish MMF. They are fast, easy to use, and relatively safe because there are no sharps or wires associated with their use. The authors report their experience using this MMF method for temporomandibular joint replacement surgery, where over the last 2 years, over 65 collective cases have been completed using this method.

Intraosseous Schwannoma of the Jaws: An Updated Review of the Literature and Report of 2 New Cases Affecting the Mandible.

Schwannomas are benign nerve sheath neoplasms composed almost entirely of Schwann cells. These tumors most often arise in the soft tissues of the head and neck. However, they seldom occur within bone. This article presents a rare case of a recurrent intraosseous schwannoma of the anterior mandible and another case of a posterior intraosseous mandibular schwannoma accessed through a sagittal split ramus osteotomy. Furthermore, an updated review of the literature on intraosseous schwannomas affecting the mandible and maxilla is provided.

Patient Safety and the Malpractice System.

The cost of health care in the United States and malpractice insurance has escalated greatly over the past 30 years. In an ideal world, the goals of the tort system would be aligned with efforts at improving safety. In fact, there is little evidence that the tort system and the processes of risk management and informed consent have improved patient safety. This article explores the disunion between patient safety and the malpractice system.

Bisphosphonate-related osteonecrosis of the jaw: clinical features, risk factors, management, and treatment outcomes of 26 patients.

PURPOSE: To report the clinical features, risk factors, management, and treatment outcomes of nitrogen-containing bisphosphonate (n-BIS)-related osteonecrosis of the jaw (BRONJ). PATIENTS AND METHODS: Patients with suspected BRONJ were referred to the School of Dentistry for evaluation and treatment. RESULTS: A total of 26 patients (9 men and 17 women, mean age 64 years) were diagnosed with BRONJ. Of the 26 patients, 23 had received n-BIS therapy for cancer and 3 for osteoporosis. BRONJ lesions were noted more frequently in the mandible and in the posterior sextants. Of the 26 patients, 16 had developed BRONJ after dentoalveolar procedures, and 10 had developed it spontaneously. The mean interval to development of BRONJ was shorter in the patients with cancer receiving intravenous n-BIS than in the patients with osteoporosis receiving oral n-BIS (37.1 versus 77.7 months, P = .02). Using the American Association of Oral and Maxillofacial Surgeons staging system, 2 patients were diagnosed with stage I lesions, 19 with stage II, and 5 with stage III lesions. The initial management of BRONJ was nonsurgical, with debridement performed at subsequent visits, if needed. The BRONJ lesions healed completely in 4 patients, healed partially in 8, remained stable in 7, and progressed in 7. The spontaneous lesions responded favorably to BRONJ management compared with lesions that developed after dentoalveolar procedures (P = .01). No significant difference was found in response to BRONJ management between patients who had continued or discontinued n-BIS therapy after the BRONJ diagnosis (P = .54). CONCLUSIONS: Long-term n-BIS therapy and recent dental procedures are consistent findings in patients with BRONJ. Spontaneous BRONJ lesions respond favorably to current BRONJ treatment strategies.

Correlations between physical properties of jawbone and dental implant initial stability.

STATEMENT OF PROBLEM: There is confusion in the literature about how physical properties of bone vary between maxillary and mandibular regions and which physical properties affect initial implant stability. PURPOSE: The purpose of this study was to determine correlations between physical properties of bone and initial implant stability, and to determine how physical properties and initial stability vary among regions of jawbone. MATERIAL AND METHODS: Four pairs of edentulous maxillae and mandibles were retrieved from fresh human cadavers. Six implants per pair were placed in different anatomical regions (maxillary anterior, right and left maxillary posterior, mandibular anterior, right and left mandibular posterior). Immediately after surgery, initial implant stability was measured with a resonance frequency device and a tapping device. Implant surgeries and initial stability measurements were performed within 72 hours of death. Elastic modulus (EM) and hardness were measured using nano-indentation. Composite apparent density (cAD) was measured using Archimedes' principle. Bone-implant contact percentage and cortical bone thickness were recorded histomorphometrically. Mixed linear models and univariate-correlation analyses were used (alpha=.05). RESULTS: Generally, mandibular bone had higher initial implant stability and physical properties than maxillary bone. Initial implant stability was higher in the anterior region than in the posterior. EM was higher in the posterior region than in the anterior; the reverse was true for cAD. CONCLUSIONS: Of the properties evaluated, cAD had the highest correlation with initial implant stability (r=0.82). Both physical properties of bone and initial implant stability differed between regions of jawbone.

Bone regeneration in mandibular distraction osteogenesis combined with compression stimulation.

PURPOSE: This study compared modified distraction osteogenesis (DO) protocol with conventional DO protocol on healing bone formation. Computer simulation was performed to understand the mechanical environment of modified DO protocol, which applies compression during the consolidation period. MATERIALS AND METHODS: Fifty rats were used in this study. Twenty-five rats in the conventional DO (control) group were sacrificed at postoperative days 11, 21, 28, 35, and 49 after osteotomy. In the modified DO (experimental) group, compression was applied on day 7 after distraction (day 18 postoperatively) for 4 days during the early consolidation period and 25 rats were sacrificed on postoperative day 19, 28, 39, 46, and 53. The histologic and radiographic findings were used to compare the 2 groups. Further, computer simulation was used to predict the mechanical environment of healing bone under conventional and modified DO protocol. RESULTS: Radiographic findings showed that the experimental group resulted in denser and wider healing bone. Histologically, the experimental group yielded more mature lamellar bone than the control group. Computer simulation showed that absolute values of tissue strains were nearly double in the control group because of the softer healing tissues. Both the experimental and control groups showed high strains at the ridge crest. Concentrated tensile strain along the distraction direction at the ridge crest might hinder bone formation at the interface, while compressive strain could facilitate the process. CONCLUSION: This study proposed a modified DO protocol of adding compression during the early consolidation period of conventional DO protocol. This new technique appears to provide faster and denser bone regeneration.

A single reformatted oblique sagittal view as an adjunct to coronal computed tomography for the evaluation of orbital floor fractures.

PURPOSE: We sought to determine whether it is beneficial to routinely include a single reformatted oblique sagittal view as an adjunct to coronal computed tomography (CT) for the evaluation and treatment of orbital floor fractures, when imaging is obtained on patients with orbital trauma. MATERIALS AND METHODS: A retrospective analysis of 12 midface CT scans was performed. All of the patients included in the study had been determined by a staff radiologist to have radiographic evidence of orbital fractures. Five surgeons who treat orbital floor fractures, but do not routinely order oblique sagittal views, were asked to evaluate the selected CT scans without being given a clinical history. The surgeons were allowed to evaluate the reformatted coronal CT and were asked to rate their ability to determine the location and the size of the fracture in a medial-lateral dimension and an anterior-posterior dimension, volume of orbital contents herniated into the maxillary sinus, and radiographic evidence of inferior rectus entrapment. The surgeons were then allowed to evaluate a single reformatted oblique sagittal view through each orbit. They were asked the same questions and these 2 additional questions, "Do you think the oblique view gave you additional information, and would it change your treatment plan?" RESULTS: Confidence in determining the size and location of the fracture in a medial-lateral dimension was not improved with the addition of the reformatted oblique sagittal view; however, location and size of the fracture in an anterior-posterior dimension and volume displaced from the orbit into the maxillary sinus and evidence of inferior rectus entrapment were improved with the addition to the oblique sagittal view. Seventy-eight percent of responders said that the oblique sagittal view provided additional information, and 18% of the responders said that the additional information changed the treatment plan. CONCLUSION: Routinely obtaining a single reformatted oblique sagittal view as an adjunct to coronal CT provides additional valuable information to the surgeon in treating orbital floor fractures. Reformatted views do not subject patients to additional radiation and the time to obtain these views is minimal.

An intra-oral hydraulic system for controlled loading of dental implants.

This study reports a method for controlling loads on an in vivo dental implant and its application for the investigation of early loading versus delayed loading of dental implants. The method was developed for the purpose of studying an ongoing hypothesis that amounts to bone loss around dental implants are related to mechanical-mediated adaptation of the alveolar bone. Using a customized intra-oral hydraulic system, the daily loading over a dental implant has been completed and recorded for six Sinclair swine. Each pig had a 5-month duration implant loading. During the experiments (loading), no analgesic treatment was supplied. The mean of the in vivo daily loadings was confirmed through an in vitro bench test after each animal was euthanized. Variations of the averaged loading input among the six animals were smaller than 10%. Preliminary data produced by the model suggests that cervical bone loss is less for early loading than for delayed loading. The current system is expected to provide a useful load control model for the study of alveolar bone adaptation around dental implants in relation to various loadings.

Effect of NSAID administration on tissue levels of immunoreactive prostaglandin E2, leukotriene B4, and (S)-flurbiprofen following extraction of impacted third molars.

Post-operative pain and inflammation are frequently managed with non-steroidal anti-inflammatory drugs (NSAIDs). Despite the prevalence of their use, however, relatively little is known about in vivo tissue concentrations of inflammatory mediators at the site of tissue injury and their modulation by NSAIDs. This study compares the effect of oral administration of the NSAID flurbiprofen, to placebo, on tissue levels of immunoreactive prostaglandin E2 (iPGE2), leukotriene B4 (iLTB4), and (S)-flurbiprofen within the surgical wound using implanted microdialysis probes in the dental impaction pain model. Twenty-four healthy patients in need of extraction of partial to complete bony mandibular third molars were recruited for this randomized, double-blind, placebo-controlled study. Following pre-operative administration of N2O/O2, midazolam i.v., and regional block anesthesia with 3% mepivacaine, each patient underwent surgical removal of their impacted third molars. Immediately following completion of the surgery, two semi-permeable microdialysis probes (3 kDa molecular weight cut-off) were implanted into each mandibular surgical site. Patients were taken to a recovery room and microdialysis samples and patient pain reports (visual analog scale, VAS) were collected at 30 min intervals for 4 h. Patients randomly received either flurbiprofen (200 mg orally) or placebo at the onset of post-operative pain. Dialysate samples were collected, frozen, and later assayed for iPGE2, iLTB4, and (S)-flurbiprofen levels. Results of this study show that flurbiprofen decreased post-operative pain by approximately 70% compared to placebo-treated patients (P < 0.001). During the 4 h post-operative timecourse of this study, flurbiprofen treatment significantly reduced peak tissue levels of iPGE2 (9.2 +/- 2.6 vs. 0.4 +/- 0.15 nM; P < 0.001), without having a significant effect on peak tissue levels of iLTB4 (2.5 +/- 1.4 vs. 1.49 +/- 0.86 nM) compared to placebo treatment. Levels of (S)-flurbiprofen significantly increased within the surgical wound exceeding therapeutic levels by 60 min after administration. Flurbiprofen is able to significantly suppress the local production of iPGE2 and provide significant analgesic efficacy without altering iLTB4 tissue levels in this model of acute post-operative inflammatory pain. These data indicate that NSAIDs selectively alter eicosanoid levels within surgical wound and evoke analgesia at time points coincident with elevated wound levels of the drug. The combined use of microdialysis probes in awake patients who provide simultaneous pain reports may offer insight into peripheral mechanisms of inflammatory mediator release and pain.