Benefits of the enhanced recovery after surgery pathway for orthognathic surgery.

The enhanced recovery after surgery (ERAS) protocol was designed to improve patient outcomes and decrease complications, opioid use, and postoperative nausea and vomiting (PONV). The aim of this retrospective cohort study was to examine the effectiveness of ERAS protocols implemented in orthognathic surgeries from 2017 to 2018 at the University of Alabama at Birmingham Hospital by measuring opioid use and PONV. Two groups were identified through chart review, a non-ERAS group (traditional) of patients who had surgery without a protocol and an ERAS group of patients who had surgery with the ERAS protocol. The anesthesia and surgical teams followed a standardized protocol for perioperative management. All procedures were performed by a single surgeon and included single- and double-jaw surgeries and adjunctive procedures. The patient charts were analyzed for postoperative opioid consumption (measured in morphine milligram equivalents, MME) and PONV. IBM SPSS Statistics version 26 was used to conduct the statistical analyses. The ERAS group received less opioids during the postoperative period than the control group (31.2 MME vs 54.6 MME, P= 0.002). The ERAS group also had a lower incidence of PONV, with 1.2 episodes of PONV compared to 2.4 episodes in the non-ERAS group (P= 0.008). This study demonstrates that the ERAS protocol is effective in decreasing postoperative opioid consumption and PONV.

Do oropharyngeal throat packs prevent fluid ingestion during orthognathic surgery?

The oropharyngeal throat pack is commonly used in oral and maxillofacial surgery despite debated evidence regarding its barrier function. The study objectives were to investigate whether the oropharyngeal pack reduces blood ingestion and to evaluate its relationship with postoperative nausea and vomiting (PONV) and throat pain. This was a single-center, parallel group, single-blind randomized controlled trial. Participants undergoing orthognathic surgery, age ≥16 years, were included in the study. After intubation and prior to surgery start, the treatment group received oropharyngeal packing; the control group received no packing. Outcome variables were the quality of gastric contents aspirated by nasogastric tube (bloody or not bloody), PONV, and throat pain (visual analog scale). Thirty patients (treatment n = 15; control n = 15) were randomized and analyzed. There was no difference between the groups in quality of gastric contents (P = 1.00) or incidence of PONV at 2 hours and 24 hours (P = 1.00). Throat pain incidence and severity at 2 hours were both higher in the treatment group, but this was not statistically significant (P = 0.128, P = 0.223). The results indicate that the oropharyngeal pack is not an effective barrier against blood ingestion. Oropharyngeal packs do not improve or worsen PONV, but may increase throat pain.

The correlation of maxillomandibular advancement and airway volume change in obstructive sleep apnea using cone beam computed tomography.

The purpose of this retrospective study was to evaluate the correlation of maxillomandibular advancement (MMA) and airway volume changes in patients with obstructive sleep apnea (OSA), and to determine the surgical skeletal movements necessary to achieve an increase in total airway volume (TAV) of ≥70%. Thirty patients with OSA treated by MMA were evaluated. Pre- and postoperative cone beam computed tomography images were used to determine the horizontal distance and angular changes in surgical parameters and linear, area, and volumetric airway parameters. Postoperatively, the horizontal distance of surgical parameters (A-point, UI, B-point, pogonion, and menton) and craniofacial angulation (SNA and SNB) increased significantly, similar to total surface area, TAV, and minimum cross-sectional area of the airway (p<0.0001). The total airway length decreased significantly (p<0.0001). The mean increase in TAV was 67.2%. There were positive correlations between linear surgical changes and the percentage change in TAV. All surgical parameters were predictive of a change in TAV ≥70%. The optimal surgical change was 6mm for A-point, 7.9mm for UI, 7.6mm for B-point, 11.2mm for pogonion, and 10mm for menton. In conclusion, maxillary advancement of less than 10mm was adequate in this study to obtain an increase in the TAV of at least 70%.

Differential enamel and osteogenic gene expression profiles in odontogenic tumors.

Odontogenic tumors occur within the jaw bones and may be derived from odontogenic epithelium or ectomesenchyme or contain active components of both tissue types. We investigated the gene expression profile of enamel matrix proteins (EMPs), genes related to osteogenesis, and the mineralization process in odontogenic tumor cell populations focusing on an ameloblastoma (AB-1), a keratocystic odontogenic tumor (KCOT-1), and a calcifying epithelial odontogenic tumor (CEOT-1). All cell populations were shown to be epithelial in origin by CK14 expression. All tested EMPs were expressed by all odontogenic tumor cell types, with higher transcript levels seen in the AB-1 population especially for AMEL, AMBN, and ODAM. CEOT-1 cell populations showed a greater content of ALP-positive cells as well as higher ALP mRNA levels. Using qRT-PCR, we found a higher expression of 8 genes in the CEOT-1 compared to the AB-1 and KCOT-1. In this study we demonstrated the establishment of AB-1, KCOT-1 and CEOT-1 cell populations. The unique gene expression profiles of AB-1, KCOT-1, and CEOT-1 cells and their interactions with the surrounding microenvironment may support their unique tumor development, progression, and survival.

Peripheral changes above and below injury level lead to prolonged vascular responses following high spinal cord injury.

Autonomic dysreflexia (AD) is a debilitating disorder producing episodes of extreme hypertension in patients with high-level spinal cord injury (SCI). Factors leading to AD include loss of vasomotor baroreflex control to regions below injury level, changes in spinal circuitry, and peripheral changes. The present study tested for peripheral changes below and above injury level 6 wk after a transection at the fourth thoracic spinal level. Changes in vascular conductance were recorded in the femoral, renal, brachial, and carotid arteries in response to intravenous injections of two alpha-adrenergic agonists, phenylephrine (PE; 0.03-100 microg/kg) and methoxamine (Meth; 1-300 microg/kg). Unlike PE, Meth is not subject to neuronal reuptake. Ganglionic blockade (0.6 mg/kg chlorisondamine) was used to eliminate the central component of the cardiovascular response. After ganglionic blockade, SCI animals exhibited prolonged vasoconstriction in response to PE in all blood vessels measured compared with those in intact animals (all, P < 0.035). However, the PE dose-response curves obtained after ganglionic blockade revealed no significant difference in the potency between the two groups (all, P > 0.06), indicating that the prolonged vasoconstriction was not due to supersensitivity to PE. In contrast to PE, vascular responses to Meth did not vary between intact and SCI groups (all P > 0.108). These results show the development of a widespread peripheral change producing prolonged vasoconstriction in response to PE, but not Meth, possibly due to reduced neuronal reuptake of PE after SCI. This is the first study to report such a change in blood vessels not only below but also above injury level. Interventions to correct this reduced reuptake may help limit the development of AD.

Mild neuritic changes are increased in the brains of fatally injured older motor vehicle drivers.

Given the expected increase in the older population and driving in this age group, concerns have been raised about the safety of older drivers. People over 65 years are over-represented in motor vehicle fatalities when calculated by distance driven. They are also at risk of neurodegenerative diseases, such as Alzheimer's disease, that affect cognitive function. We have examined the brains of older drivers (15M:12F) who died as a result of a motor vehicle accident (MVA) to determine the extent of Alzheimer's disease-related neurofibrillary changes (neuritic plaques and neurofibrillary tangles), Lewy body pathology and cerebrovascular disease and compared them to a control group of older licenced drivers (23M:5F) who died of other causes. The prevalence of moderate or severe neuritic plaque pathology was less than expected for the general population of this age and there was no difference between the groups. However, mild neuritic plaque pathology was increased for MVA deaths compared to controls. There was no evidence of vascular dementia or dementia with Lewy bodies. The current mandatory age-related re-licencing procedures in NSW may contribute to the low percentage of drivers with severe pathology. Further research into the role of mild pathology in cognitive impairment and older drivers is warranted.

Cardiovascular and temperature changes in spinal cord injured rats at rest and during autonomic dysreflexia.

In patients with high spinal cord injuries autonomic dysfunction can be dangerous, leading to medical complications such as postural hypotension, autonomic dysreflexia and temperature disturbance. While animal models have been developed to study autonomic dysreflexia, associated temperature changes have not been documented. Our aim here was to use radiotelemetry and infrared thermography in rodents to record the development of cardiovascular and skin temperature changes following complete T4 transection. In adult male Wistar rats (n=5), responses were assessed prior to spinal cord injury (intact) and for 6 weeks following injury. Statistical analysis by a repeated-measure ANOVA revealed that following spinal cord injury (SCI), rats exhibited decreased mean arterial pressure (MAP, average decrease of 26 mmHg; P<0.035) and elevated heart rate (HR, average increase of 65 bpm, P<0.035) at rest. The basal core body temperature following SCI was also significantly lower than intact levels (-0.9 degrees C; P<0.0035). Associated with this decreased basal core temperature following SCI was an increased skin temperature of the mid-tail and hindpaw (+5.6 and +4.0 degrees C, respectively; P<0.0003) consistent with decreased cutaneous vasoconstrictor tone. Autonomic dysreflexia, in response to a 1 min colorectal distension (25 mmHg), was fully developed by 4 weeks after spinal cord transection, producing increases in MAP greater than 25 mmHg (P<0.0003). In contrast to the tachycardia seen in intact animals in response to colorectal distension, SCI animals exhibited bradycardia (P<0.0023). During episodes of autonomic dysreflexia mid-tail surface temperature decreased (approximately -1.7 degrees C, P<0.012), consistent with cutaneous vasoconstriction. This is the first study to compare cardiovascular dysfunction with temperature changes following spinal cord transection in rats.

Increased neurofibrillary tangles in the brains of older pedestrians killed in traffic accidents.

BACKGROUND/AIMS: Older people are over-represented in pedestrian fatalities, and it has been suggested that the presence of cognitive impairment or dementia in these individuals may contribute to their accidents. Using neuropathological methods, we aimed to compare the prevalence of dementia pathology in fatally injured older pedestrians with similarly aged ambulatory subjects who died from other causes. METHODS: The brains of 52 pedestrians (65-93 years) and 52 controls (65-92 years) were assessed for neurofibrillary tangles (NFT), neuritic plaques, Lewy bodies and vascular lesions using established neuropathological criteria. RESULTS: The examination for Alzheimer's disease (AD) pathology showed that 43% of the pedestrians had NFT scores of III-VI using Braak and Braak staging, compared with 23% of the controls (p < 0.05, Fisher's exact test), indicating incipient, possible or probable AD. There were no differences in the prevalence of pathology for vascular dementia or dementia with Lewy bodies. CONCLUSION: These results suggest that cognitive decline associated with AD, even in the earliest stages of the disease, may be a factor in fatal traffic accidents for older pedestrians. Special measures for pedestrian safety are necessary in areas with high densities of older citizens and especially for those diagnosed as having a mild cognitive impairment or AD.

A vertebral dislocation model of spinal cord injury in rats.

A new model of spinal cord injury (SCI) has been developed in the rat, which produces axonal and vascular injury within the spinal cord through lateral displacement of the vertebral column. An electromechanical feedback-controlled device produces the injury by displacing the vertebral column to the left hand side. The speed and lateral displacement is controllable by the user, and the resulting injury ranges from no histologically evident injury, to total disruption of the vertebral column with associated widespread axonal and vascular damage. Histological and immunohistological techniques were employed to correlate mechanical parameters with the extent of pathological injury of spinal cord. Axonal injury was most severe in the left lateral white matter, and vascular injury was concentrated in the gray matter.

Developmental onset of functional activity in the wallaby whisker cortex in response to stimulation of the infraorbital nerve.

This study used the extrauterine development of a marsupial wallaby to investigate the onset of functional activity in the somatosensory pathway from the whiskers. In vivo recordings were made from the somatosensory cortex from postnatal day (P) 55 to P138, in response to electrical stimulation of the infraorbital nerve supplying the mystacial whiskers. Current source density analysis was used to localize the responses within the cortical depth. This was correlated with development of cortical lamination and the onset of whisker-related patches, as revealed by cytochrome oxidase. The earliest evoked activity occurred at P61, when layers 5 and 6 are present, but layer 4 has not yet developed. This activity showed no polarity reversal with depth, suggesting activity in thalamocortical afferents. By P72 synaptic responses were detected in developing layer 4 and cytochrome oxidase showed the first hint of segregation into whisker-related patches. These patches were clear by P86. The evoked response at this age showed synaptic activity first in layer 4 and then in deep layer 5/upper layer 6. With maturity, responses became longer lasting with a complex sequence of synaptic activity at different cortical depths. The onset of functional activity is coincident with development of layer 4 and the onset of whisker-related pattern formation. A similar coincidence is seen in the rat, despite the markedly different chronological timetable, suggesting similar developmental mechanisms may operate in both species.

Cholinergic depletion by IgG192-saporin retards development of rat barrel cortex.

This study examines the role of cholinergic projections from the basal forebrain on development of the rodent barrel cortex. Pups were administered the immunotoxin IgG192-saporin (0.1 microg) intraventricularly at postnatal day (P) 0 and sacrificed at P1-P7. One ventricle was injected with saporin while the other side received saline, allowing comparison between the two sides of the same animal, as well as with controls receiving saline only. Compared to control animals, neuronal loss in the basal forebrain was present on both sides of saporin-treated pups but was significantly greater on the toxin-treated side, in all age groups and regions sampled. Depletion of acetylcholine did not prevent the formation of the barrel pattern, however it delayed its emergence by approximately 1 day. At P4, the thickness of layer IV barrel cortex was also significantly reduced; this reduction was undetectable by P7. From P3 to P5, the ratios of intensity of staining for acetylcholinesterase between the barrel centres and septa on the toxin-treated side were significantly lower than those on the saline side, although normal densities were present by P7. Thus, the depletion of cholinergic innervation at birth causes a transient delay in the development of the barrel pattern during the first postnatal week.

[Is there new knowledge on embryology and functional anatomy of human mimetic muscles and the upper lip? A contribution to point selection, skin incision and muscle reconstruction in primary lip-nose reconstruction of uni- and bilateral lip-jaw-palatal clefts]. / Gibt es neue Erkenntnisse zur Embryologie und funktionellen Anatomie der humanen mimischen Muskulatur und der Oberlippe? Ein Beitrag zur Punktewahl, Hautschnittführung und Muskelrekonstruktion bei der primären Lippen-Nasen-Plastik ein- und doppelseitiger LKG-Spalten.

BACKGROUND: The great variety of primary cheiloplastic procedures in CLP patients shows that there is disagreement regarding the embryological development of this part of the face, the point selection, skin incision philosophy, and the macroscopic and microscopic functional anatomy of the human muscles of facial expression. We suppose from findings in Asian and African populations that the real embryological development of the upper lip differs from current textbook descriptions. Our own anatomical and embryological investigations serve as a basis for a critical discussion of different techniques of muscle reconstruction, point selection, and skin incision and for a description of an embryologically, functionally, and anatomically oriented operation technique for different entities of CLP. METHODS: The findings of this study result from investigations of the embryonal and early fetal development from the 26th to the 112th i.u. day in REM pictures of the Anatomical Institute of the University of Göttingen (n = 8) and serial histological investigations of the Carnegie and Hooker-Humphrey Collections at the Armed Forces Institute of Pathology, Washington, D.C. (n = 40). Furthermore, we carried out microsurgical dissections of the muscles of facial expression, the osseous and cartilaginous parts of the nose, and the midfacial sutures in two adult heads without congenital disorders and one newborn head with a primary unilateral complete cleft of the lip and alveolus. RESULTS AND DISCUSSION: The formation of the lower third of the upper lip is the result of contact of the maxillary bulges in the midline below the prolabium. According to this finding, the point selections and skin incisions have to be modified in the midline region in different types of uni- and bilateral CLP. Our technique of primary dissection, reorientation, and suturing of the muscles of facial expression is presented. The muscle reconstruction has to be performed independently from the skin preparation.

Fluororuby as a marker for detection of acute axonal injury in rat spinal cord.

Axonal damage is a common pathological consequence of spinal cord injury. Previous studies have detected axonal injury with silver stains for degeneration or immunohistochemistry for alterations in components such as beta-amyloid precursor protein, neurofilament or ubiquitin. Fluororuby has recently been introduced as a neuronal tracer in studies of spinal cord injury and regeneration. Our study was carried out to determine whether Fluororuby can be used to identify injured axons and monitor the time course of axonal damage. Adult rats underwent needle puncture injury to the white matter in the midline and lateral spinal cord at T11. At the same time, 0.05 microl of Fluororuby was injected into the cord at the same sites. After survival times ranging from 6 h to 3 weeks, spinal cords were cut into longitudinal frozen sections and examined with confocal microscopy. Fluororuby was found to label key features of axonal injury including axonal swelling, retraction balls and disrupted axons. Damaged axons close to the injury site were consistently labeled within 6 h, with indications of swollen and disconnected axons spreading further from the site during the first week. Fewer injured axons were labeled after 1 week survival, but the marker revealed longer distances of degenerating axons both distal and rostral to the injury site. Our findings indicate that Fluororuby is a quick, sensitive, reliable and technically simple fluorescent marker for early stages of acute axonal injury and degeneration.

Extent and distribution of vascular brain injury in pediatric road fatalities.

This study used a multidisciplinary approach to examine the brains of pediatric road trauma fatalities in the Sydney area over a 3-year period. The brains of 32 children (0-16 years) were examined: 20 pedestrians, nine passengers, and three cyclists. The extent and distribution of brain injury was assessed, peak linear head acceleration determined, and the severity of brain damage was compared to that previously reported for adults using the same scoring method. Skull fractures (20/32) and subarachnoid haemorrhage (22/32) were the commonest head injuries. In general, the neuropathology was similar to that seen in adults, with a high percentage of damage in the corpus callosum and gliding contusions within the subcortical white matter. Intracerebral hemorrhage was relatively rare. For frontal and occipital head impacts, the corpus callosum was the most injured part of the brain, followed by the deep central structures and the temporal lobes, whereas for lateral impacts, the injuries were more evenly distributed. Comparison of the current data for children with the vascular injury sector scores reported for adults suggests that the brains of children are more severely damaged for the same peak linear head acceleration.

Strength analysis of Le Fort I osteotomy fixation: titanium versus resorbable plates.

PURPOSE: The purpose of this study was to compare the biomechanical characteristics of metallic and polymeric fixation systems using a 3-dimensional skull model to simulate clinical conditions of maxillary advancement and loading. MATERIAL AND METHODS: Standard titanium, prebent titanium, and resorbable plates and mesh were applied to surgically altered polyurethane skulls. The constructs were loaded using an Instron machine (Instron Inc, Canton, MA) in anterior-posterior (AP) and inferior-superior (IS) directions. The load displacement, load to failure, and deformation magnitudes and modes of failure were recorded. Statistical studies included analysis of variance (ANOVA) at P <.05. RESULTS: Elastic stiffness was different among groups in the AP direction, but no significant difference was found in the IS direction. The IS loading direction load displacement (stiffness) was significantly greater than that on AP loading. The maximum load for permanent deformation was larger in the AP direction, while the maximum load for breaking was larger in the IS direction. CONCLUSION: The overall evaluation of the model and test analyses supported the relative value of this in vitro system and study procedure. All systems showed load capacity magnitudes above 285 N (64 lbs) and more elastic resistance in the IS direction. The resorbable systems showed lower elastic stiffness compared with the titanium systems, but they appear to be adequate for fixation and withstanding the forces of mastication.

Soft tissue changes of the upper lip associated with maxillary advancement in obstructive sleep apnea patients.

PURPOSE: This retrospective study evaluated the horizontal and vertical soft tissue changes that occur with maxillary advancement surgery with a Le Fort I osteotomy with concomitant anatomic reorientation of the nasolabial musculature. SUBJECTS AND METHODS: Fifteen OSA patients who underwent maxillary advancement with a Le Fort I osteotomy without adjunctive nasal soft tissue procedures were studied after a minimum of 8 months of follow-up. The V-Y technique was used to close the maxillary vestibular incision. Only cases with minimal vertical movement (< 3.5 mm) in which no orthodontics were used were included. The average maxillary advancement was 8.0 +/- 2.5 mm, measured at the upper incisor (UPI) and the average vertical movement was 0.7 +/- 1.8 mm. The horizontal and vertical soft tissue change in subnasale (SN), labrale superiorus (LS), superior stomion (SS), nasal tip (NT), nasolabial angle (NLA), and lip length were measured in each patient and correlated with hard tissue measurements at anterior nasal spine (ANS) and UPI. The effect of lip thickness on these soft tissue changes also was evaluated. RESULTS: Using mean data, the horizontal soft-to-hard-tissue ratio for LS to UPI was 0.80:1, with a concomitant vertical (superior) soft tissue change to hard tissue advancement of 0.16:1. Lip length did not change significantly. All patients except 1 showed a slight decrease in nasolabial angle. The average decrease was 5 (range, -10 to +7 ). There was no statistically significant correlation between the degree of change in NLA and the amount of maxillary advancement. CONCLUSION: This study showed that advancement of the maxilla when controlling vertical movement resulted in the a hard-to-soft-tissue ratio of LS:UPI of 0.80:1. NLA did not change significantly.

Transplantation of nasal olfactory tissue promotes partial recovery in paraplegic adult rats.

Recent reports have highlighted the potential therapeutic role of olfactory ensheathing cells for repair of spinal cord injuries. Previously ensheathing cells collected from the olfactory bulbs within the skull were used. In humans a source of these cells for autologous therapy lies in the nasal mucosa where they accompany the axons of the olfactory neurons. The aim of the present study was to test the therapeutic potential of nasal olfactory ensheathing cells for spinal cord repair. Olfactory ensheathing cells cultured from the olfactory lamina propria or pieces of lamina propria from the olfactory mucosa were transplanted into the transected spinal cord. Three to ten weeks later these animals partially recovered movement of their hind limbs and joints which was abolished by a second spinal cord transection. Control rats, receiving collagen matrix, respiratory lamina propria or culture medium, did not recover hind limb movement. Recovery of movement was associated with recovery of spinal reflex circuitry, assessed using the rate-sensitive depression of the H-reflex from an interosseous muscle. Histological analysis of spinal cords grafted with olfactory tissue demonstrated nerve fibres passing through the transection site, serotonin-positive fibres in the spinal cord distal to the transection site, and retrograde labelling of brainstem raphe and gigantocellularis neurons from injections into the distal cord, indicating regeneration of descending pathways. Thus, olfactory lamina propria transplantation promoted partial restoration of function after relatively short recovery periods. This study is particularly significance because it suggests an accessible source of tissue for autologous grafting in human paraplegia.

Afferent ingrowth and onset of activity in the rat trigeminal nucleus.

A novel in vitro preparation, consisting of the rat brainstem with the trigeminal ganglion attached, has been used to study the anatomical and functional development of the trigeminal nucleus from embryonic day (E)13 to postnatal day (P)6. Neurobiotin injections into the trigeminal ganglion showed that primary afferents had reached the trigeminal tract by E13 and had grown simple, mainly unbranched, collaterals into all levels of the nucleus by E15. By E17, these collaterals were extensively branched, with occasional boutons present. Patches of intense neurobiotin-labelled terminals, corresponding to whisker-related patterns, were first seen at E20 and became clearer over the next few days. Terminal arbours at this stage were relatively localized and densely branched, with many boutons. Responses from the trigeminal nucleus were recorded with suction electrodes, following stimulation of the trigeminal ganglion. Recordings from the main sensory nucleus showed a postsynaptic response was first present at E15. At E16, bath application of AP5 and DNQX showed that the response contained both NMDA and AMPA components, with NMDA predominating (75%). The NMDA : AMPA ratio remained high until P1, then gradually declined to 50% by P6. The postsynaptic response was also reduced by bath application of bicuculline, indicating the presence of a GABAA-mediated excitatory component. GABAergic excitation was present at all ages but was maximal from E20 to P1, the age at which whisker-related patterns are developing. It is hypothesized that both GABAergic excitation and NMDA receptor activation play a role in the consolidation of trigeminal connections, and are thus important in the development of whisker-related patterns.