The Role of the Fascia-Only Anterolateral Thigh Flap in Extremity Reconstruction: The Fascia-Only Anterolateral Thigh Flap

BACKGROUND

Free flap selection in extremity reconstruction can be challenging. The ideal flap has to be thin and pliable to achieve optimal contour and function. We explore the role of the fascia-only anterolateral thigh (fALT) flap in extremity reconstruction.

METHODS

We conducted a retrospective review of our experience using fALT-free flap for extremity reconstruction over a 2-year period. Patient demographics, mechanism of injury, flap characteristics, complications- and follow-up were recorded. Descriptive statistics were calculated.

RESULTS

Twelve patients were included. The median (interquartile range [IQR]) age was 34 (28-52) years. One fALT flap was used for upper extremity reconstruction, while 11 flaps were used for lower extremity reconstruction (4 for lower third of the leg, 4 for dorsum of foot, and 3 for heel). The median (IQR) flap surface area was 90 (63-120) cm2 and time from injury to reconstruction was 10 (6-16) days. The postoperative course was uneventful for all flaps except for 1 flap failure and 1 delayed healing. The median (IQR) follow-up was 2 (1-4) months. In all cases, durable soft tissue reconstruction was achieved with no need for revisions.

CONCLUSIONS

The fALT-free flap can be successfully used in extremity reconstruction. The ALT fascia has robust perfusion that allows for the harvest of a large flap that can be surfaced with a split thickness skin graft. Its thin pliable tissue provides excellent contour for the hand, distal leg, and foot that does not require future thinning, optimizing the cosmetic and functional result.

The Association Between Craniofacial Fracture Patterns and Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a rare but potentially devastating complication of craniofacial trauma. Approximately half of patients with TON sustain permanent vision loss. In this study, we sought to identify the most common fracture patterns associated with TON. We performed a retrospective review of craniomaxillofacial CT scans of trauma patients who presented to the R Adams Cowley Shock Trauma Center from 2015 to 2017. Included were adult patients who had orbital fractures with or without other facial fractures. Patients diagnosed with TON by a formal ophthalmologic examination were analyzed. Craniofacial fracture patterns were identified. Bivariate analysis and multivariate logistic regression were performed to identify craniofacial fracture patterns most commonly associated with TON. A total of 574 patients with orbital fractures who met inclusion criteria [15 (2.6%)] were diagnosed with TON. The median [interquartile range (IQR)] age was 44 (28-59) years. Patients with optic canal fractures and sphenoid sinus fractures had greater odds of TON compared with patients who did not have these fracture types [adjusted odds ratio (aOR) 95% confidence interval (CI) 31.8 (2.6->100), 8.1 (2.7-24.4), respectively]. Patients who sustain optic canal and sphenoid sinus fractures in the setting of blunt facial trauma are at increased odds of having a TON. Surgeons and other physicians involved in the care of these patients should be aware of this association.

Development and validation of a risk calculator for postoperative diplopia following orbital fracture repair in adults

Postoperative diplopia is the most common complication following orbital fracture repair (OFR). Existing evidence on its risk factors is based on single-institution studies and small sample sizes. Our study is the first multi-center study to develop and validate a risk calculator for the prediction of postoperative diplopia following OFR. We reviewed trauma patients who underwent OFR at two high-volume trauma centers (2015-2019). Excluded were patients < 18 years old and those with postoperative follow-up < 2 weeks. Our primary outcome was incidence/persistence of postoperative diplopia at ≥ 2 weeks. A risk model for the prediction of postoperative diplopia was derived using a development dataset (70% of population) and validated using a validation dataset (remaining 30%). The C-statistic and Hosmer-Lemeshow tests were used to assess the risk model accuracy. A total of n = 254 adults were analyzed. The factors that predicted postoperative diplopia were: age at injury, preoperative enophthalmos, fracture size/displacement, surgical timing, globe/soft tissue repair, and medial wall involvement. Our predictive model had excellent discrimination (C-statistic = 80.4%), calibration (P = 0.2), and validation (C-statistic = 80%). Our model rules out postoperative diplopia with a 100% sensitivity and negative predictive value (NPV) for a probability < 8.9%. Our predictive model rules out postoperative diplopia with an 87.9% sensitivity and a 95.8% NPV for a probability < 13.4%. We designed the first validated risk calculator that can be used as a powerful screening tool to rule out postoperative diplopia following OFR in adults.

Patient-Specific Implant Customization for Treatment of Internal Orbital Fractures Using Office-Based Three-Dimensional Printing

OBJECTIVE

Three-dimensional (3D) modeling technology aids the reconstructive surgeon in designing and tailoring individualized implants for the reconstruction of complex craniofacial fractures. Three-dimensional modeling and printing have traditionally been outsourced to commercial vendors but can now be incorporated into both private and academic craniomaxillofacial practices. The goal of this report is to present a low-cost, standardized office-based workflow for restoring bony orbital volume in traumatic orbital fractures.

METHODS

Patients with internal orbital fractures requiring open repair were identified. After the virtual 3D models were created by iPlan 3.0 Cranial CMF software (Brainlab), the models were printed using an office-based 3D printer to shape and modify orbital plates to correctly fit the fracture defect. The accuracy of the anatomic reduction and the restored bony orbital volume measurements were determined using postoperative computed tomography images and iPlan software.

RESULTS

Nine patients fulfilled the inclusion criteria: 8 patients had unilateral fractures and 1 patient had bilateral fractures. Average image processing and print time were 1.5 hours and 3 hours, respectively. The cost of the 3D printer was $2500 and the average material cost to print a single orbital model was $2. When compared with the uninjured side, the mean preoperative orbital volume increase and percent difference were 2.7 ± 1.3 mL and 10.9 ± 5.3%, respectively. Postoperative absolute volume and percent volume difference between the orbits were -0.2 ± 0.4 mL and -0.8 ± 1.7%, respectively.

CONCLUSIONS

Office-based 3D printing can be routinely used in the repair of internal orbital fractures in an efficient and cost-effective manner to design the implant with satisfactory patient outcomes.

Pediatric Orbital Fractures

The unique anatomy and physiology of the growing craniofacial skeleton predispose children to different fracture patterns as compared to adults. Diagnosis and treatment of pediatric orbital fractures can be challenging. A thorough history and physical examination are essential for the diagnosis of pediatric orbital fractures. Physicians should be aware of symptoms and signs suggestive of trapdoor fractures with soft tissue entrapment including symptomatic diplopia with positive forced ductions, restricted ocular motility (regardless of conjunctival abnormalities), nausea/vomiting, bradycardia, vertical orbital dystopia, enophthalmos, and hypoglobus. Equivocal radiologic evidence of soft tissue entrapment should not withhold surgery. A multidisciplinary approach is recommended for the accurate diagnosis and proper management of pediatric orbital fractures.

Geometric Mismatch Promotes Anatomic Repair in Periorbital Bony Defects in Skeletally Mature Yucatan Minipigs

Porous tissue-engineered 3D-printed scaffolds are a compelling alternative to autografts for the treatment of large periorbital bone defects. Matching the defect-specific geometry has long been considered an optimal strategy to restore pre-injury anatomy. However, studies in large animal models have revealed that biomaterial-induced bone formation largely occurs around the scaffold periphery. Such ectopic bone formation in the periorbital region can affect vision and cause disfigurement. To enhance anatomic reconstruction, geometric mismatches are introduced in the scaffolds used to treat full thickness zygomatic defects created bilaterally in adult Yucatan minipigs. 3D-printed, anatomically-mirrored scaffolds are used in combination with autologous stromal vascular fraction of cells (SVF) for treatment. An advanced image-registration workflow is developed to quantify the post-surgical geometric mismatch and correlate it with the spatial pattern of the regenerating bone. Osteoconductive bone growth on the dorsal and ventral aspect of the defect enhances scaffold integration with the native bone while medio-lateral bone growth leads to failure of the scaffolds to integrate. A strong positive correlation is found between geometric mismatch and orthotopic bone deposition at the defect site. The data suggest that strategic mismatch >20% could improve bone scaffold design to promote enhanced regeneration, osseointegration, and long-term scaffold survivability.

Treatment of Persistent Post-traumatic Diplopia - An Algorithmic Approach to Patient Stratification and Operative Management

Study Design

Retrospective chart review of revisional orbital surgery outcomes in patients with diplopia from prior operative treatment of orbital trauma.

Objective

Our study seeks to review our experience with management of persistent post-traumatic diplopia in patients with previous orbital reconstruction and present a novel patient stratification algorithm predictive of improved outcomes.

Methods

A retrospective chart review was performed on adult patients at Wilmer Eye Institute at Johns Hopkins Hospital and at the University of Maryland Medical Center who underwent revisional orbital surgery for correction of diplopia for the years 2005-2020. Restrictive strabismus was determined by Lancaster red-green testing coupled with computed tomography and/or forced duction. Globe position was assessed by computed tomography. Seventeen patients requiring operative intervention according to study criteria were identified.

Results

Globe malposition affected fourteen patients and restrictive strabismus affected eleven patients. In this select group, improvement in diplopia occurred in 85.7% of cases with globe malposition and in 90.1% of cases with restrictive strabismus. One patient underwent additional strabismus surgery subsequent to orbital repair.

Conclusions

Post-traumatic diplopia in patients with prior orbital reconstruction can be successfully managed in appropriate patients with a high degree of success. Indications for surgical management include (1) globe malposition and (2) restrictive strabismus. High resolution computer tomography and Lancaster red-green testing discriminate these from other causes that are unlikely to benefit from orbital surgery.

Local health department engagement with workplaces during the COVID-19 pandemic—Examining barriers of and facilitators to outbreak investigation and mitigation

Objectives

To document local health department (LHD) COVID-19 prevention or mitigation activities at workplaces in the United States and identify facilitators for and barriers to these efforts.

Methods

We conducted a web-based, cross-sectional national probability survey of United States LHDs (n = 181 unweighted; n = 2,284 weighted) from January to March 2022, collecting information about worker complaints, surveillance, investigations, relationships and interactions with employers/businesses, and LHD capacity.

Results

Overall, 94% LHD respondents reported investigating workplace-linked COVID-19 cases; however, 47% reported insufficient capacity to effectively receive, investigate and respond to COVID-19-related workplace safety complaints. Prior relationships with jurisdiction employers and LHD personnel with formal occupational health and safety (OHS) training were predictors of proactive outreach to prevent COVID-19 spread in workplaces (p &lt; 0.01 and p &lt; 0.001). LHD size predicted OHS personnel and sufficient financial resources to support workplace investigation and mitigation activities (p &lt; 0.001).

Conclusions

Differences in LHD capacity to effectively respond to communicable disease spread in workplaces may exacerbate health disparities, especially between rural and urban settings. Improving LHD OHS capacity, especially in smaller jurisdictions, could facilitate effective prevention and mitigation of workplace communicable disease spread.

Sub-chronic oral exposure of tungsten induces markers of kidney injury

Tungsten is a naturally occurring transition element used in a broad range of applications. As a result of its extensive use, we are increasingly exposed to tungsten from our environment, including potable water, since tungsten can become bioaccessible in ground sources. The kidneys are particularly susceptible to tungsten exposure as this is the main site for tungsten excretion. In this study, we investigated the prolonged effects of tungsten on the kidneys and how this may impact injury and function. When mice were exposed to tungsten in their drinking water for 1-month, kidney function had not significantly changed. Following 3-month exposure, mice were presented with deterioration in kidney function as determined by serum and urine creatinine levels. During 3-months of tungsten exposure, murine kidneys demonstrated significant increases in the myofibroblast marker ⍺SMA, and extracellular matrix products: fibronectin, collagen, and matricellular proteins. In addition, Masson's trichrome and H&E staining revealed an increase in fibrotic tissue and vacuolization of tubular epithelial cells, respectively, from kidneys of tungsten-treated mice, indicative of renal injury. In vitro treatment of kidney fibroblasts with tungsten led to increased proliferation and upregulation of Transforming Growth Factor Beta 1 (TGFβ1), which was consistent with the appearance of fibroblast-to-myofibroblast transition (FMT) markers. Our data suggest that continuous exposure to tungsten impairs kidney function that may lead to the development of chronic kidney disease (CKD).

Gaseous and Particulate Content of Laser Tattoo Removal Plume

BACKGROUND

There is increasing awareness of the potential hazards of surgical plumes. The plume associated with laser tattoo removal remains uncharacterized.

OBJECTIVE

To determine the gaseous, particulate, and microbiological content of the laser tattoo removal plume.

MATERIALS AND METHODS

Air sampling was performed during laser tattoo removal from pig skin and from patients. Measurement of metals, volatile organic compounds (VOCs), carbon monoxide (CO), hydrogen sulfide (HS), and ultrafine particulates (UPs) as well as bacterial 16S ribosomal DNA sequencing were performed.

RESULTS

Metals were identified in the plume from both pig and human skin. Volatile organic compounds were found at similar levels within and outside the treatment room. Several bacterial phyla were detected in the treatment room, but not outside. High levels of UPs were measured throughout the treatment room during tattoo removal from pig skin. Ultrafine particulates were detected at low levels in the room periphery during tattoo removal from human skin, but at higher levels in the immediate treatment zone. HS and CO were not detected.

CONCLUSION

Metals, VOCs, HS, and CO were found at levels below applicable occupational exposure limits. The presence of bacteria is of uncertain significance, but may be hazardous. High levels of UPs require further investigation.

Tungsten accumulates in the intervertebral disc and vertebrae stimulating disc degeneration and upregulating markers of inflammation and pain

Tungsten is incorporated in many industrial goods, military applications and medical devices due to its ability to impart flexibility, strength and conductance to materials. Emerging evidence has questioned the safety of tungsten exposure as studies have demonstrated it can promote tumour formation, induce pulmonary disease and alter immune function. Although tungsten is excreted from the body it can accumulate in certain organs such as the brain, colon, liver, kidneys, spleen and bones, where most of the bioaccumulation occurs. Whether prolonged tungsten exposure leads to accumulation in other tissues is unknown. The present study demonstrated that mice exposed to 15 ppm sodium tungstate for 4 weeks in their drinking water showed comparable accumulation in both the bony vertebrae and intervertebral discs (IVDs). Lumbar IVD height was significantly reduced in tungsten-exposed mice and accompanied by decreased proteoglycan content and increased fibrosis. In addition to catabolic enzymes, tungsten also increased the expression of the inflammatory cytokines IL-1β and tumour necrosis factor (TNF)-α as well as the neurotrophic factors nerve growth factor (NGF) and brain-derived nerve factor (BDNF) in IVD cells. Tungsten significantly increased the presence of nociceptive neurons at the endplates of IVDs as observed by the expression of calcitonin gene-related peptide (CGRP) and anti-protein gene product 9.5 (PGP9.5) in endplate vessels. The present study provided evidence that tungsten may enhance disc degeneration and fibrosis as well as increase the expression of markers for pain. Therefore, tungsten toxicity may play a role in disc degeneration disease.

Tungsten Increases Sex-Specific Osteoclast Differentiation in Murine Bone

Tungsten is a naturally occurring metal that is increasingly used in industry and medical devices, and is labeled as an emerging environmental contaminant. Like many metals, tungsten accumulates in bone. Our previous data indicate that tungsten decreases differentiation of osteoblasts, bone-forming cells. Herein, we explored the impact of tungsten on osteoclast differentiation, which function in bone resorption. We observed significantly elevated osteoclast numbers in the trabecular bone of femurs following oral exposure to tungsten in male, but not female mice. In order to explore the mechanism(s) by which tungsten increases osteoclast number, we utilized in vitro murine primary and cell line pre-osteoclast models. Although tungsten did not alter the adhesion of osteoclasts to the extracellular matrix protein, vitronectin, we did observe that tungsten enhanced RANKL-induced differentiation into tartrate-resistant acid phosphatase (TRAP)-positive mononucleated osteoclasts. Importantly, tungsten alone had no effect on differentiation or on the number of multinucleated TRAP-positive osteoclasts. Enhanced RANKL-induced differentiation correlated with increased gene expression of differentiated osteoclast markers Nfatc1, Acp5, and Ctsk. Although tungsten did not alter the RANK surface receptor expression, it did modulate its downstream signaling. Co-exposure of tungsten and RANKL resulted in sustained positive p38 signaling. These findings demonstrate that tungsten enhances sex-specific osteoclast differentiation, and together with previous findings of decreased osteoblastogenesis, implicate tungsten as a modulator of bone homeostasis.

Resolution of Vertical Gaze Following a Delayed Presentation of Orbital Floor Fracture With Inferior Rectus Entrapment: The Contributions of Charles E. Iliff and Joseph S. Gruss in Orbital Surgery

Introduction

Orbital floor fractures occur commonly as a result of blunt trauma to the face and periorbital region. Orbital floor fractures with a "trapdoor" component allow both herniation and incarceration of contents through a bone defect into the maxillary sinus as the bone rebounds faster than the soft tissue, trapping muscle, fat, and fascia in the fracture site. In children, the fractured floor, which is often hinged on one side, tends to return toward its original anatomical position due to the incomplete nature of the fracture and elasticity of the bone. The entrapment of the inferior rectus muscle itself is considered a true surgical emergency-prolonged entrapment frequently leads to muscle ischemia and necrosis leading to permanent limitation of extraocular motility and difficult to correct diplopia. For this reason, prompt surgical intervention is recommended by most surgeons. In adults, true entrapment of the muscle itself is not as common because the orbital floor is not as elastic and fractures are more complete.

Methods

We present an adult patient with an isolated orbital floor fracture with clinical and radiologic evidence of true entrapment of the inferior rectus muscle itself.

Results

Despite the delayed surgical repair (4 days after the injury), the patient's inferior rectus muscle function returned to near normal with mild upward gaze diplopia.

Conclusions

Inferior rectus entrapment in adults may more likely be associated with immobilization of the muscle without total vascular compression/incarceration significant enough to lead to complete ischemic necrosis.

COVID-19 Outbreak Among Employees at a Meat Processing Facility - South Dakota, March-April 2020

On March 24, 2020, the South Dakota Department of Health (SDDOH) was notified of a case of coronavirus disease 2019 (COVID-19) in an employee at a meat processing facility (facility A) and initiated an investigation to isolate the employee and identify and quarantine contacts. On April 2, when 19 cases had been confirmed among facility A employees, enhanced testing for SARS-CoV-2, the virus that causes COVID-19, was implemented, so that any employee with a COVID-19-compatible sign or symptom (e.g., fever, cough, or shortness of breath) could receive a test from a local health care facility. By April 11, 369 COVID-19 cases had been confirmed among facility A employees; on April 12, facility A began a phased closure* and did not reopen during the period of investigation (March 16-April 25, 2020). At the request of SDDOH, a CDC team arrived on April 15 to assist with the investigation. During March 16-April 25, a total of 929 (25.6%) laboratory-confirmed COVID-19 cases were diagnosed among 3,635 facility A employees. At the outbreak's peak, an average of 67 cases per day occurred. An additional 210 (8.7%) cases were identified among 2,403 contacts of employees with diagnosed COVID-19. Overall, 48 COVID-19 patients were hospitalized, including 39 employees and nine contacts. Two employees died; no contacts died. Attack rates were highest among department-groups where employees tended to work in proximity (i.e., <6 feet [2 meters]) to one another on the production line. Cases among employees and their contacts declined to approximately 10 per day within 7 days of facility closure. SARS-CoV-2 can spread rapidly in meat processing facilities because of the close proximity of workstations and prolonged contact between employees (1,2). Facilities can reduce this risk by implementing a robust mitigation program, including engineering and administrative controls, consistent with published guidelines (1).

COVID-19 Among Workers in Meat and Poultry Processing Facilities - 19 States, April 2020

Congregate work and residential locations are at increased risk for infectious disease transmission including respiratory illness outbreaks. SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is primarily spread person to person through respiratory droplets. Nationwide, the meat and poultry processing industry, an essential component of the U.S. food infrastructure, employs approximately 500,000 persons, many of whom work in proximity to other workers (1). Because of reports of initial cases of COVID-19, in some meat processing facilities, states were asked to provide aggregated data concerning the number of meat and poultry processing facilities affected by COVID-19 and the number of workers with COVID-19 in these facilities, including COVID-19-related deaths. Qualitative data gathered by CDC during on-site and remote assessments were analyzed and summarized. During April 9-27, aggregate data on COVID-19 cases among 115 meat or poultry processing facilities in 19 states were reported to CDC. Among these facilities, COVID-19 was diagnosed in 4,913 (approximately 3%) workers, and 20 COVID-19-related deaths were reported. Facility barriers to effective prevention and control of COVID-19 included difficulty distancing workers at least 6 feet (2 meters) from one another (2) and in implementing COVID-19-specific disinfection guidelines.* Among workers, socioeconomic challenges might contribute to working while feeling ill, particularly if there are management practices such as bonuses that incentivize attendance. Methods to decrease transmission within the facility include worker symptom screening programs, policies to discourage working while experiencing symptoms compatible with COVID-19, and social distancing by workers. Source control measures (e.g., the use of cloth face covers) as well as increased disinfection of high-touch surfaces are also important means of preventing SARS-CoV-2 exposure. Mitigation efforts to reduce transmission in the community should also be considered. Many of these measures might also reduce asymptomatic and presymptomatic transmission (3). Implementation of these public health strategies will help protect workers from COVID-19 in this industry and assist in preserving the critical meat and poultry production infrastructure (4).

Link N suppresses interleukin-1β-induced biological effects on human osteoarthritic cartilage

Osteoarthritis (OA) is a disease of diarthrodial joints associated with extracellular matrix proteolytic degradation under inflammatory conditions, pain and disability. Currently, there is no therapy to prevent, reverse or modulate the disease course. The present study aimed at evaluating the regenerative potential of Link N (LN) in human OA cartilage in an inflammatory milieu and determining if LN could affect pain-related behaviour in a knee OA mouse injury model. Osteo-chondro OA explants and OA chondrocytes were treated with LN in the presence of interleukin-1β (IL-1β) to simulate an osteoarthritic environment. Quantitative von Frey polymerase chain reaction and Western blotting were performed to determine the effect of LN on matrix protein synthesis, catabolic enzymes, cytokines and nerve growth factor expression. Partial medial meniscectomy (PMM) was performed on the knee of C57BL/6 mice and, 12 weeks post-surgery, mice were given a 5 µg intra-articular injection of LN or phosphate-buffered saline. A von Frey test was conducted over 24 h to measure the mechanical allodynia in the hind paw. LN modulated proteoglycan and collagen synthesis in human OA cartilage through inhibition of IL-1β-induced biological effects. LN also supressed IL-1β-induced upregulation of cartilage-degrading enzymes and inflammatory molecules in OA chondrocytes. Upon investigation of the canonical signalling pathways IL-1β and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), LN resulted to significantly inhibit NF-κB activation in a dose-dependent manner. In addition, LN suppressed mechanical allodynia in an OA PMM mouse model. Results supported the concept that LN administration could provide therapeutic potential in OA.

Short link N acts as a disease modifying osteoarthritis drug

Osteoarthritis (OA) is a degenerative joint disease characterised by a progressive degradation of articular cartilage and underlaying bone and is associated with pain and disability. Currently, there is no medical treatment to reverse or even retard OA. Based on our previous reports, where we establish the repair potential of short Link N (sLN) in the intervertebral disc, a cartilage-like tissue, we hypothesise that sLN may hold similar promises in the repair of articular cartilage. This study aimed to determine if sLN, could prevent OA disease progression. Skeletally mature New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT) of their left femorotibial joints to induce joint degeneration typical of OA. Beginning 3 weeks post-operatively, and every three weeks thereafter for 12 weeks, either saline (1 mL) or sLN (100 μg in 1 mL saline) was injected intraarticularly into the operated knee. Six additional rabbits underwent sham surgery but without ACLT or post-operative injections. The effects on gross joint morphology and cartilage histologic changes were evaluated. In the Saline group, prominent erosion of articular cartilage occurred in both femoral condyle compartments and the lateral compartment of the tibial plateau while, sLN treatment reduced the severity of the cartilage damage in these compartments of the knee showing erosion. Furthermore, statistically significant differences were detected between the joint OA score of the saline and sLN treated groups (p = 0.0118). Therefore, periodic intraarticular injection of sLN is a promising nonsurgical treatment for preventing or retarding OA progression, by reducing cartilage degradation.

Pediatric Nasoorbitoethmoid Fractures: Cause, Classification, and Management

BACKGROUND

Currently, there is a paucity of information on the presentation and proper management of pediatric nasoorbitoethmoid fractures. The purpose of this study was to examine the incidence, cause, associated injuries, and management of these fractures. Furthermore, the authors sought to assess outcomes after transnasal wiring or suture canthopexy for type III nasoorbitoethmoid fractures.

METHODS

A retrospective cohort review was performed of all patients with nasoorbitoethmoid fractures who presented to a Level I trauma center from 1990 to 2010. Charts and computed tomographic imaging were reviewed, and nasoorbitoethmoid fractures were labeled based on the Markowitz-Manson classification system. Patient fracture patterns, demographics, characteristics, and outcomes were recorded. Univariate and multivariate methods were used to compare groups.

RESULTS

A total of 63 pediatric patients were identified in the study period. The sample's mean age was 8.78 ± 4.08 years, and 28.6 percent were girls. The sample included 18 type I injuries, 28 type II injuries, and 17 type III injuries. No significant demographic differences were found between patients with type I, II, and III fractures (p > 0.05). Operative intervention was pursued in 16.7, 46.4, and 82.4 percent of type I, II, and III nasoorbitoethmoid fractures, respectively. In patients with type III nasoorbitoethmoid fractures, no patients with transnasal wiring developed telecanthus.

CONCLUSIONS

Pediatric nasoorbitoethmoid fractures are uncommon injuries. Type I fracture can often be treated with close observation. However, type II and III injury patterns should be evaluated for operative intervention. Transnasal wiring is an effective method to prevent traumatic telecanthus deformity in type III fracture patterns.

Closed-incision negative-pressure therapy decreases complications in ventral hernia repair with concurrent panniculectomy

PURPOSE

Ventral hernia repair with concurrent panniculectomy (VHR-PAN) is associated with high wound complication rates despite reported increased patient satisfaction. Some surgeons believe negative-pressure therapy after primary closure of the surgical incision (ciNPT) may lower wound complications in high-risk abdominal wounds. This study aims to evaluate if ciNPT improves outcomes in patients undergoing VHR-PAN.

METHODS

An 8-year retrospective cohort study was performed on patients who underwent VHR-PAN. Patients were divided into two groups: those who received closed-incision negative-pressure therapy ("ciNPT") and those who received standard sterile dressings ("SSD"). The primary outcome of interest was the rate of postoperative complications between these groups. Complications were subdivided into surgical site occurrences (which included surgical site occurrences that required an intervention), return to the operating room, and hernia recurrence.

RESULTS

A total of 104 patients were analyzed: 62 in the ciNPT group and 42 in the SSD group. Median follow-up duration was similar between both groups (182 days vs 195 days, p = 0.624). Patients in the ciNPT group had fewer total complications (57% vs. 83%, p = 0.004) and fewer SSO (47% vs. 69%, p = 0.025). However, no differences were noted when comparing individual complications (SSI, wound dehiscence, skin necrosis, chronic wound, seroma, and hematoma). There was no difference in return to the operating room (27% vs. 26%, p = 0.890) or hernia recurrence (21% vs 19%, p = 0.811). Multivariate analysis showed that ciNPT decreased the risk of SSOPI nearly fourfold (odds ratio 0.28, 95% CI = 0.09-0.87, p = 0.027).

CONCLUSIONS

This study showed that closed-incision negative-pressure therapy in ventral hernia repair with concurrent panniculectomy may decrease the rate of wound complications in this high-risk population.

A Cluster Randomized Controlled Trial of a Total Worker Health® Intervention on Commercial Construction Sites

This study evaluated the efficacy of an integrated Total Worker Health^® program, “All the Right Moves”, designed to target the conditions of work and workers’ health behaviors through an ergonomics program combined with a worksite-based health promotion Health Week intervention. A matched-pair cluster randomized controlled trial was conducted on ten worksites (five intervention (n = 324); five control sites (n = 283)). Worker surveys were collected at all sites pre- and post- exposure at one- and six-months. Linear and logistic regression models evaluated the effect of the intervention on pain and injury, dietary and physical activity behaviors, smoking, ergonomic practices, and work limitations. Worker focus groups and manager interviews supplemented the evaluation. After controlling for matched intervention and control pairs as well as covariates, at one-month following the ergonomics program we observed a significant improvement in ergonomic practices (B = 0.20, p = 0.002), and a reduction in incidences of pain and injury (OR = 0.58, p = 0.012) in the intervention group. At six months, we observed differences in favor of the intervention group for a reduction in physically demanding work (B = −0.25, p = 0.008), increased recreational physical activity (B = 35.2, p = 0.026) and higher consumption of fruits and vegetables (B = 0.87, p = 0.008). Process evaluation revealed barriers to intervention implementation fidelity and uptake, including a fissured multiemployer worksite, the itinerant nature of workers, competing production pressures, management support, and inclement weather. The All the Right Moves program had a positive impact at the individual level on the worksites with the program. For the longer term, the multi-organizational structure in the construction work environment needs to be considered to facilitate more upstream, long-term changes.

Link N as a therapeutic agent for discogenic pain

Neurotrophins (NTs) are the major contributors of sensory axonal sprouting, neural survival, regulation of nociceptive sensory neurons, inflammatory hyperalgesia, and neuropathic pain. Intervertebral disc (IVD) cells constitutively express NTs. Their expression is upregulated by proinflammatory cytokines present in the IVD during degeneration, which can promote peripheral nerve ingrowth and hyperinnervation, leading to discogenic pain. Currently, there are no targeted therapies that decrease hyperinnervation in degenerative disc disease. Link N is a naturally occurring peptide with a high regenerative potential in the IVD. Therefore, the suitability of Link N as a therapeutic peptide for suppressing NTs, which are known modulators and mediators of pain, was investigated. The aim of the present study is to determine the effect of Link N on NTs expression, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and their cognate receptors TrkA and TrkB as they are directly correlated with symptomatic back pain. Furthermore, the neurotransmitter (substance P) was also evaluated in human annulus fibrosus (AF) cells stimulated with cytokines. Human AF cells isolated from normal IVDs were stimulated with interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the presence or absence of Link N. NGF release in the media was evaluated by Western blotting. Total RNA was isolated and gene expression was measured using real-time PCR. Gene expression of NGF, BDNF, TrkA, and TrkB significantly decreased in human disc cells stimulated with either IL-1β or TNF-α supplemented with Link N when compared to the cells stimulated only with IL-1β or TNF-α. NGF protein expression was also suppressed in AF cells coincubated with Link N and IL-1β when compared to the cells stimulated only with IL-1β. Link N can suppress the stimulation of NGF, BDNF, and their receptors TrkA and TrkB in AF cells in an inflammatory milieu. Thus, coupled with previous observations, this suggests that administration of Link N has the potential to not only repair the discs in early stages of the disease but also suppress pain.

Is there more to the clinical outcome in posttraumatic reconstruction of the inferior and medial orbital walls than accuracy of implant placement and implant surface contouring? A prospective multicenter study to identify predictors of clinical outcome

PURPOSE

Reconstruction of orbital wall fractures is demanding and has improved dramatically with the implementation of new technologies. True-to-original accuracy of reconstruction has been deemed essential for good clinical outcome, and reasons for unfavorable clinical outcome have been researched extensively. However, no detailed analysis on the influence of plate position and surface contour on clinical outcome has yet been published.

MATERIALS AND METHODS

Data from a previous study were used for an ad-hoc analysis to identify predictors for unfavorable outcome, defined as diplopia or differences in globe height and/or globe projection of >2 mm. Presumed predictors were implant surface contour, aberrant implant dimension or position, accuracy of reconstructed orbital volume, and anatomical fracture topography according to the current AO classification.

RESULTS

Neither in univariable nor in multivariable regression models were unfavorable clinical outcomes associated with any of the presumed radiological predictors, and no association of the type of implant, i.e., standard preformed, CAD-based individualized and non-CAD-based individualized with its surface contour could be shown.

CONCLUSION

These data suggest that the influence of accurate mechanical reconstruction on clinical outcomes may be less predictable than previously believed, while the role of soft-tissue-related factors may have been underestimated.

Link-N: The missing link towards intervertebral disc repair is species-specific

Introduction

Degeneration of the intervertebral disc (IVD) is a frequent cause for back pain in humans and dogs. Link-N stabilizes proteoglycan aggregates in cartilaginous tissues and exerts growth factor-like effects. The human variant of Link-N facilitates IVD regeneration in several species in vitro by inducing Smad1 signaling, but it is not clear whether this is species specific. Dogs with IVD disease could possibly benefit from Link-N treatment, but Link-N has not been tested on canine IVD cells. If Link-N appears to be effective in canines, this would facilitate translation of Link-N into the clinic using the dog as an in vivo large animal model for human IVD degeneration.

Materials and methods

This study’s objective was to determine the effect of the human and canine variant of Link-N and short (s) Link-N on canine chondrocyte-like cells (CLCs) and compare this to those on already studied species, i.e. human and bovine CLCs. Extracellular matrix (ECM) production was determined by measuring glycosaminoglycan (GAG) content and histological evaluation. Additionally, the micro-aggregates’ DNA content was measured. Phosphorylated (p) Smad1 and -2 levels were determined using ELISA.

Results

Human (s)Link-N induced GAG deposition in human and bovine CLCs, as expected. In contrast, canine (s)Link-N did not affect ECM production in human CLCs, while it mainly induced collagen type I and II deposition in bovine CLCs. In canine CLCs, both canine and human (s)Link-N induced negligible GAG deposition. Surprisingly, human and canine (s)Link-N did not induce Smad signaling in human and bovine CLCs. Human and canine (s)Link-N only mildly increased pSmad1 and Smad2 levels in canine CLCs.

Conclusions

Human and canine (s)Link-N exerted species-specific effects on CLCs from early degenerated IVDs. Both variants, however, lacked the potency as canine IVD regeneration agent. While these studies demonstrate the challenges of translational studies in large animal models, (s)Link-N still holds a regenerative potential for humans.

An Inspection Tool and Process to Identify Modifiable Aspects of Acute Care Hospital Patient Care Units to Prevent Work-Related Musculoskeletal Disorders

A dearth of practical resources is available for evaluating ergonomic risk factors in dynamic health care work environments. Of particular need are tools for inspecting patient care environments for hazards. The goal of this study was to describe the development and application of an inspection tool and a process for identifying hazards inherent in the modifiable aspects of the physical environment to reduce injury risk to hospital workers. Through an iterative and participatory process, the tool and inspection process were developed with three purposes in mind: (a) create a framework for the inspection of physical work environments and physical conditions of work associated with injury risk (hazards), (b) document the physical conditions, and (c) provide feedback to decision makers. The tool and process were used by an ergonomics researcher on four patient care units as part of the Be Well, Work Well Total Worker Health® intervention. The resulting inspection process provided a structured method for recognizing hazards in the dynamic modifiable physical work environment and reporting both observations and recommendations to decision makers. The development and implementation of the inspection tool provided guidance to modify the physical work environment by implementing ergonomic solutions. The tool allowed the organization to plan and prioritize ergonomic hazard abatement (e.g. resource allocation and tracking trends). Within a Total Worker Health® framework, this tool can measure work practices which can then be used to inform organizational programs and policies within a health care setting.

The validity and reliability of computed tomography orbital volume measurements

PURPOSE

Orbital volume calculations allow surgeons to design patient-specific implants to correct volume deficits. It is estimated that changes as small as 1 ml in orbital volume can lead to enophthalmos. Awareness of the limitations of orbital volume computed tomography (CT) measurements is critical to differentiate between true volume differences and measurement error. The aim of this study is to analyze the validity and reliability of CT orbital volume measurements.

MATERIALS AND METHODS

A total of 12 cadaver orbits were scanned using a standard CT maxillofacial protocol. Each orbit was dissected to isolate the extraocular muscles, fatty tissue, and globe. The empty bony orbital cavity was then filled with sculpting clay. The volumes of the muscle, fat, globe, and clay (i.e., bony orbital cavity) were then individually measured via water displacement. The CT-derived volumes, measured by manual segmentation, were compared to the direct measurements to determine validity.

RESULTS AND CONCLUSIONS

The difference between CT orbital volume measurements and physically measured volumes is not negligible. Globe volumes have the highest agreement with 95% of differences between -0.5 and 0.5 ml, bony volumes are more likely to be overestimated with 95% of differences between -1.8 and 2.6 ml, whereas extraocular muscle volumes have poor validity and should be interpreted with caution.

The "Crumple Zone" hypothesis: Association of frontal sinus volume and cerebral injury after craniofacial trauma

PURPOSE

The paranasal sinuses are complex anatomical structures of unknown significance. One hypothesis theorizes that the sinuses, in the event of a traumatic injury, function as a crumple zone to distribute and absorb energy to protect the brain and other critical structures. The current study investigates the association between frontal sinus (FS) volume and the severity of cerebral insults following craniofacial trauma.

METHODS

All patients with FS fracture admitted to a level 1 trauma center from 2011 to 2014 were retrospectively reviewed. FS volumes were measured from computed tomography (CT) on admission using a proprietary region growing segmentation tool. Head injuries were classified based on the presence of specific types of intracranial pathology and their corresponding Marshall Score.

RESULTS

FS fracture was identified on the admission CT in 165 patients. Male patients had significantly larger FS volume compared to females (8.4 ± 6.3 vs. 4.0 ± 2.9 cm³, p < 0.001). Smaller FS volume was significantly associated with a worse Marshall Score (p = 0.041) and a higher incidence of cerebral contusion (p = 0.016) independent of age, gender, mechanism, ISS, and admission GCS. The inverse correlation between FS volume and the Marshall Score was also statistically significant (Spearman correlation coefficient r = -0.19, p = 0.015). Smaller FS volume was observed in patients who suffered intracranial insults, underwent neurosurgical interventions, and had worse clinical outcomes and trended towards significance with respect to an association with subarachnoid hemorrhage (p = 0.074) and subdural hematoma (p = 0.080), and had a statistically significant association with longer length of stay (p < 0.001).

CONCLUSION

FS volume is inversely correlated with the severity of intracranial pathology following craniofacial trauma. Our findings are consistent with the "crumple zone" hypothesis and suggest that the FS likely plays a role in mitigating intracranial injury. Furthermore, FS volume is significantly different between male and female patients. This is a novel finding that warrants further validation.

Orbital fracture repair outcomes with preformed titanium mesh implants and comparison to porous polyethylene coated titanium sheets

BACKGROUND

Restoration of orbital volume after internal orbital fractures can prevent enophthalmos. A variety of allografts are commonly used including titanium mesh with and without porous polyethylene coating. Some controversy exists over the use of uncoated titanium mesh in the orbit. Newer products contoured to the three dimensional orbital anatomy aim to improve reestablishment of the complex orbital shape though studies of outcomes with their use are limited.

METHODS

A retrospective chart review was performed to evaluate surgical outcomes in all patients who underwent orbital fracture repair with DePuy/Synthes titanium MatrixMIDFACE prefabricated implants (PFTi) as compared with porous polyethylene/titanium hybrid implants (PPETi) including Stryker Medpor Titan, MTB, and BTB implants. Incidence of reoperation, diplopia, and movement restriction between PFTi and PPETi groups and the risk ratio of the above outcomes between implant types were compared.

RESULTS

A total of 464 orbital implants were reviewed. Patients were divided by implant type with 195 patients receiving a PFTi implant and 269 patients receiving PPETi implant. (PFTi) and 269 had placement of a porous polyethylene/titanium hybrid implant. Despite statistically significant increased probability of utilization in more complex and delayed fractures, the PFTi implant showed no significant difference in complication profile or reoperation rate compared to the more commonly used PPETi.

CONCLUSIONS

PFTi implants, designed to replicate the native orbital shape, have similar surgical outcomes and no difference in complication profile compared to standard porous polyethylene/titanium implants hybrid plates.

Human cartilaginous endplate degeneration is induced by calcium and the extracellular calcium-sensing receptor in the intervertebral disc

The cartilaginous endplates (CEPs) are thin layers of hyaline cartilage found adjacent to intervertebral discs (IVDs). In addition to providing structural support, CEPs regulate nutrient and metabolic exchange in the disc. In IVD pathogenesis, CEP undergoes degeneration and calcification, compromising nutrient availability and disc cell metabolism. The mechanism(s) underlying the biochemical changes of CEP in disc degeneration are currently unknown. Since calcification is often observed in later stages of IVD degeneration, we hypothesised that elevations in free calcium (Ca2+) impair CEP homeostasis. Indeed, our results demonstrated that the Ca2+ content was consistently higher in human CEP tissue with grade of disc degeneration. Increasing the levels of Ca2+ resulted in decreases in the secretion and accumulation of collagens type I, II and proteoglycan in cultured human CEP cells. Ca2+ exerted its effects on CEP matrix protein synthesis through activation of the extracellular calcium-sensing receptor (CaSR); however, aggrecan content was also affected independent of CaSR activation as increases in Ca2+ directly enhanced the activity of aggrecanases. Finally, supplementing Ca2+ in our IVD organ cultures was sufficient to induce degeneration and increase the mineralisation of CEP, and decrease the diffusion of glucose into the disc. Thus, any attempt to induce anabolic repair of the disc without addressing Ca2+ may be impaired, as the increased metabolic demand of IVD cells would be compromised by decreases in the permeability of the CEP.

Biomaterials and Tissue Engineering Strategies for Conjunctival Reconstruction and Dry Eye Treatment

The ocular surface is a component of the anterior segment of the eye and is covered by the tear film. Together, they protect the vital external components of the eye from the environment. Injuries, surgical trauma, and autoimmune diseases can damage this system, and in severe cases, tissue engineering strategies are necessary to ensure proper wound healing and recovery. Dry eye is another major concern and a complicated disease affecting the ocular surface. More effective and innovative therapies are required for better outcomes in treating dry eye. This review focuses on the regenerative medicine of the conjunctiva, which is an essential part of the ocular surface system. Features and advances of different types of biomolecular materials, and autologous and allogeneic tissue grafts are summarized and compared. Specifically, vitrigel, a collagen membrane and novel material for use on the ocular surface, offers significant advantages over other biomaterials. This review also discusses a breakthrough microfluidic technology, “organ-on-a-chip” and its potential application in investigating new therapies for dry eye.

Tungsten Promotes Sex-Specific Adipogenesis in the Bone by Altering Differentiation of Bone Marrow-Resident Mesenchymal Stromal Cells

Tungsten is a naturally occurring metal that increasingly is being incorporated into industrial goods and medical devices, and is recognized as an emerging contaminant. Tungsten preferentially and rapidly accumulates in murine bone in a concentration-dependent manner; however the effect of tungsten deposition on bone biology is unknown. Other metals alter bone homeostasis by targeting bone marrow-derived mesenchymal stromal cell (MSC) differentiation, thus, we investigated the effects of tungsten on MSCsin vitroandin vivoIn vitro, tungsten shifted the balance of MSC differentiation by enhancing rosiglitazone-induced adipogenesis, which correlated with an increase in adipocyte content in the bone of tungsten-exposed, young, male mice. Conversely, tungsten inhibited osteogenesis of MSCsin vitro; however, we found no evidence that tungsten inhibited osteogenesisin vivo Interestingly, two factors known to influence adipogenesis are sex and age of mice. Both female and older mice have enhanced adipogenesis. We extended our study and exposed young female and adult (9-month) male and female mice to tungsten for 4 weeks. Although tungsten accumulated to a similar extent in young female mice, it did not promote adipogenesis. Interestingly, tungsten did not accumulate in the bone of older mice; it was undetectable in adult male mice, and just above the limit of detect in adult female mice. Surprisingly, tungsten enhanced adipogenesis in adult female mice. In summary, we found that tungsten alters bone homeostasis by altering differentiation of MSCs, which could have significant implications for bone quality, but is highly dependent upon sex and age.

Orbital Floor Fracture with Atypical Extraocular Muscle Entrapment Pattern and Intraoperative Asystole in an Adult

Extraocular muscle entrapment in a nondisplaced orbital fracture, although a well-known entity in pediatric trauma, is atypical in adults. It can present with a triad of bradycardia, nausea, and in rare cases, syncope, and result in severe fibrosis of damaged and incarcerated muscle. We present a case of muscle entrapment in a partially nondisplaced two-wall orbital fracture with accompanying preoperative bradycardia and intraoperative asystole in an adult.

Virtual Surgical Planning for Orbital Reconstruction

The advent of computer-assisted technology has revolutionized planning for complex craniofacial operations, including orbital reconstruction. Orbital reconstruction is ideally suited for virtual planning, as it allows the surgeon to assess the bony anatomy and critical neurovascular structures within the orbit, and plan osteotomies, fracture reductions, and orbital implant placement with efficiency and predictability. In this article, we review the use of virtual surgical planning for orbital decompression, posttraumatic midface reconstruction, reconstruction of a two-wall orbital defect, and reconstruction of a large orbital floor defect with a custom implant. The surgeon managing orbital pathology and posttraumatic orbital deformities can benefit immensely from utilizing virtual planning for various types of orbital pathology.

14-3-3 Proteins Buffer Intracellular Calcium Sensing Receptors to Constrain Signaling

Calcium sensing receptors (CaSR) interact with 14-3-3 binding proteins at a carboxyl terminal arginine-rich motif. Mutations identified in patients with familial hypocalciuric hypercalcemia, autosomal dominant hypocalcemia, pancreatitis or idiopathic epilepsy support the functional importance of this motif. We combined total internal reflection fluorescence microscopy and biochemical approaches to determine the mechanism of 14-3-3 protein regulation of CaSR signaling. Loss of 14-3-3 binding caused increased basal CaSR signaling and plasma membrane levels, and a significantly larger signaling-evoked increase in plasma membrane receptors. Block of core glycosylation with tunicamycin demonstrated that changes in plasma membrane CaSR levels were due to differences in exocytic rate. Western blotting to quantify time-dependent changes in maturation of expressed wt CaSR and a 14-3-3 protein binding-defective mutant demonstrated that signaling increases synthesis to maintain constant levels of the immaturely and maturely glycosylated forms. CaSR thus operates by a feed-forward mechanism, whereby signaling not only induces anterograde trafficking of nascent receptors but also increases biosynthesis to maintain steady state levels of net cellular CaSR. Overall, these studies suggest that 14-3-3 binding at the carboxyl terminus provides an important buffering mechanism to increase the intracellular pool of CaSR available for signaling-evoked trafficking, but attenuates trafficking to control the dynamic range of responses to extracellular calcium.

Computer-Assisted Three-Dimensional Planning for Orbital Decompression

Thyroid-associated orbitopathy is the most common cause of unilateral or bilateral proptosis in adults. A mainstay of surgical treatment is orbital decompression utilizing osteotomies to increase the size of the affected bony orbit to accommodate the larger soft tissue volume. Over the past several decades, numerous approaches have been described for orbital decompression. However, given the intricate osseous and soft tissue anatomy within the orbit, orbital decompression is a potentially hazardous intervention. With advances in three-dimensional imaging and virtual planning, extensive orbital decompressions can be performed safely and efficiently. In this report, we describe two cases of three-wall orbital decompressions using three-dimensional planning.

Vitrified collagen-based conjunctival equivalent for ocular surface reconstruction

The main functions of the conjunctiva, an essential part of the ocular surface, are to maintain the equilibrium of the tear film and to protect the eye. Upon injuries, the prerequisite to successful ocular surface repair is conjunctival reconstruction. Tissue engineering techniques, including transplantation of autografts, amniotic membranes and numerous synthetic/natural materials, have been developed. However, none of these strategies is completely satisfactory due to lack of goblet cell repopulation, poor mechanical properties or non-standardized preparation procedure. Here, we cultured conjunctival epithelial cells on vitrified collagen membranes and developed a tissue equivalent for repairing damaged conjunctiva. Optimized vitrified collagen has superior mechanical and optical properties to previous biomaterials for ocular surface application, and its unique fibrillar structure significantly benefited conjunctival epithelial cell growth and the phenotypic development in vitro. In a rabbit model, vitrified collagen greatly promoted conjunctival regeneration with rapid re-epithelization, sufficient repopulation of goblet cells and minimized fibrosis and wound contracture, proved by gene expression analyses and histological staining. In conclusion, we have demonstrated the potential suitability of utilizing vitrified collagen-based tissue equivalent in ocular surface reconstruction.

Retrocaruncular approach for the repair of medial orbital wall fractures: an anatomical and clinical study

The aim of this article is to investigate a retrocaruncular approach for repairing medial orbital wall fractures. A total of 10 fresh cadaver orbits were dissected to investigate a transconjunctival approach to the orbit posterior to the caruncle. Medical records of consecutive patients with medial orbital wall fractures repaired via a retrocaruncular incision at Wilmer Eye Institute over a 10-year period were retrospectively reviewed. The study was approved by the Johns Hopkins Medical Institution's Institutional Review Board. Feasibility of this approach was clearly demonstrated on all cadavers. Horner muscle was observed to be directly attached to the caruncle and remained undisturbed throughout the retrocaruncular approach. For each of the 174 patients reviewed, this approach allowed successful access to the fracture and proper implant placement. The origin of the inferior oblique muscle was divided in only 19 patients. Sutures were not used for conjunctival incision closure in any patient. For 120 patients who underwent acute repair, the percentage with enophthalmos (≥ 2 mm) decreased from 34% preoperatively to 4% postoperatively; extraocular motility deficit decreased from 41 to 11%. Postoperative complications included recurrence of the preexisting retrobulbar hemorrhage, conjunctival granuloma, and temporary torsional diplopia, each in one patient. The retrocaruncular transconjunctival incision is an effective and safe approach for repairing medial orbital wall fractures with minimal complications. The retrocaruncular incision offers advantages over dividing the caruncle because Horner muscle is left undisturbed, and the incision heals well without suturing.

Analysis of quantitative magnetic resonance imaging and biomechanical parameters on human discs with different grades of degeneration

PURPOSE

To establish relationships between quantitative MRI (qMRI) and biomechanical parameters in order to help inform and interpret alterations of human intervertebral discs (IVD) with different grades of degeneration.

MATERIALS AND METHODS

The properties of the nucleus pulposus (NP) and annulus fibrosus (AF) of each IVD of 10 lumbar spines (range, 32-77 years) were analyzed by qMRI (relaxation times T1 and T2, magnetization transfer ratio [MTR], and apparent diffusion coefficient [ADC]), and tested in confined compression and dynamic shear.

RESULTS

T1 and T2 significantly decreased in both the NP and AF with increasing degeneration grades while the MTR increased significantly with grade 4. In contrast to the other qMRI parameters, the ADC had a tendency to decrease with increasing grade. Disc degeneration caused a decrease in the aggregate modulus, hydraulic permeability and shear modulus magnitude along with an increase in phase angle in the AF. In contrast, disc degeneration of NPs demonstrated decreases in shear modulus and phase angle.

CONCLUSION

Our studies indicate that qMRI can be used as a noninvasive diagnostic tool in the detection of IVD properties with the potential to help interpret and detect early, middle, and late stages of degeneration. QMRI of human IVD can therefore become a very important diagnostic assessment tool in determining the functional state of the disc.

Assessing risk of health care-acquired Legionnaires' disease from environmental sampling: the limits of using a strict percent positivity approach

BACKGROUND

Elevated percent positivity (≥30%) of Legionella in hospital domestic water systems has been suggested as a metric for assessing the risk of health care-acquired Legionnaires' disease (LD).

METHODS

We examined the validity of this metric by analyzing data from peer-reviewed studies containing reports of Legionella prevalence in hospital water (ie, percent positivity) and temporally matched reports of patients with health care-acquired LD.

RESULTS

Our literature review identified 31 peer-reviewed publications reporting matched data. We abstracted a total of 206 data points, representing 119 hospitals, from these articles. We determined that the proposed 30% positivity metric has 59% sensitivity and 74% specificity (ie, a 41% false-negative rate and a 26% false-positive rate). These notable error rates could have significant implications, given that we identified 16 peer-reviewed articles and 6 government guidance documents that referenced the 30% positivity metric as a risk assessment tool.

CONCLUSIONS

Environmental sampling of hospital water distribution systems for Legionella can be an important component of risk management for LD. However, the possible consequence of using a percent positivity metric with low sensitivity and specificity is that many hospitals might fail to mitigate when a true risk is present, or might unnecessarily allocate limited resources to deal with a negligible risk.

Calcium signaling regulates trafficking of familial hypocalciuric hypercalcemia (FHH) mutants of the calcium sensing receptor

Calcium-sensing receptors (CaSRs) regulate systemic Ca(2+) homeostasis. Loss-of-function mutations cause familial benign hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism (NSHPT). FHH/NSHPT mutations can reduce trafficking of CaSRs to the plasma membrane. CaSR signaling is potentiated by agonist-driven anterograde CaSR trafficking, leading to a new steady state level of plasma membrane CaSR, which is maintained, with minimal functional desensitization, as long as extracellular Ca(2+) is elevated. This requirement for CaSR signaling to drive CaSR trafficking to the plasma membrane led us to reconsider the mechanism(s) contributing to dysregulated trafficking of FHH/NSHPT mutants. We simultaneously monitored dynamic changes in plasma membrane levels of CaSR and intracellular Ca(2+), using a chimeric CaSR construct, which allowed explicit tracking of plasma membrane levels of mutant or wild-type CaSRs in the presence of nonchimeric partners. Expression of mutants alone revealed severe defects in plasma membrane targeting and Ca(2+) signaling, which were substantially rescued by coexpression with wild-type CaSR. Biasing toward heterodimerization of wild-type and FHH/NSHPT mutants revealed that intracellular Ca(2+) oscillations were insufficient to rescue plasma membrane targeting. Coexpression of the nonfunctional mutant E297K with the truncation CaSRΔ868 robustly rescued trafficking and Ca(2+) signaling, whereas coexpression of distinct FHH/NSHPT mutants rescued neither trafficking nor signaling. Our study suggests that rescue of FHH/NSHPT mutants requires a steady state intracellular Ca(2+) response when extracellular Ca(2+) is elevated and argues that Ca(2+) signaling by wild-type CaSRs rescues FHH mutant trafficking to the plasma membrane.