The Use of Bone Wax in Hemostatic Control for Total Knee and Hip Arthroplasties: A Systematic Review.

Background/Objectives: Blood loss can be a serious complication in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA). Various methods are used by surgeons to achieve hemostatic control in these patients. Complications are associated with perioperative blood loss. In this systematic review, we examined the efficacy of using bone wax to control bleeding in patients undergoing THA and TKA. Methods: The PRISMA model was used to systematically identify and aggregate articles for this study. The PubMed and EMBASE databases were used to search individual studies that examined the use of bone wax in THA or TKA. After applying the search term "bone wax", 2478 articles were initially identified. After inclusion and exclusion criteria were applied, three articles were aggregated for this systematic review. Results: The use of bone wax in THA and TKA decreased blood loss in patients undergoing these operations. Postoperative blood loss following surgery was lower in the bone wax groups compared to the control groups as well. Patients in the bone wax groups also required fewer blood transfusions than those who did not receive bone wax. Conclusions: Bone wax appears to be another modality that can be used by physicians to maintain hemostatic control in THA or TKA patients. Reduced blood loss and transfusion rates in surgery can increase patient outcomes. More studies are needed to examine the efficacy of bone wax in comparison with other hemostatic tools.

Quantitative hemodynamic imaging: a method to correct the effects of optical properties on laser speckle imaging.

Significance: Studying cerebral hemodynamics may provide diagnostic information on neurological conditions. Wide-field imaging techniques, such as laser speckle imaging (LSI) and optical intrinsic signal imaging, are commonly used to study cerebral hemodynamics. However, they often do not account appropriately for the optical properties of the brain that can vary among subjects and even during a single measurement. Here, we describe the combination of LSI and spatial-frequency domain imaging (SFDI) into a wide-field quantitative hemodynamic imaging (QHI) system that can correct the effects of optical properties on LSI measurements to achieve a quantitative measurement of cerebral blood flow (CBF). Aim: We describe the design, fabrication, and testing of QHI. Approach: The QHI hardware combines LSI and SFDI with spatial and temporal synchronization. We characterized system sensitivity, accuracy, and precision with tissue-mimicking phantoms. With SFDI optical property measurements, we describe a method derived from dynamic light scattering to obtain absolute CBF values from LSI and SFDI measurements. We illustrate the potential benefits of absolute CBF measurements in resting-state and dynamic experiments. Results: QHI achieved a 50-Hz raw acquisition frame rate with a 10×10 mm field of view and flow sensitivity up to ∼4 mm/s. The extracted SFDI optical properties agreed well with a commercial system (R2≥0.98). The system showed high stability with low coefficients of variations over multiple sessions within the same day (<1%) and over multiple days (<4%). When optical properties were considered, the in-vivo hypercapnia gas challenge showed a slight difference in CBF (-1.5% to 0.5% difference). The in-vivo resting-state experiment showed a change in CBF ranking for nine out of 13 animals when the correction method was applied to LSI CBF measurements. Conclusions: We developed a wide-field QHI system to account for the confounding effects of optical properties on CBF LSI measurements using the information obtained from SFDI.

Intrinsic, widefield optical imaging of hemodynamics in rodent models of Alzheimer's disease and neurological injury.

The complex cerebrovascular network is critical to controlling local cerebral blood flow (CBF) and maintaining brain homeostasis. Alzheimer's disease (AD) and neurological injury can result in impaired CBF regulation, blood-brain barrier breakdown, neurovascular dysregulation, and ultimately impaired brain homeostasis. Measuring cortical hemodynamic changes in rodents can help elucidate the complex physiological dynamics that occur in AD and neurological injury. Widefield optical imaging approaches can measure hemodynamic information, such as CBF and oxygenation. These measurements can be performed over fields of view that range from millimeters to centimeters and probe up to the first few millimeters of rodent brain tissue. We discuss the principles and applications of three widefield optical imaging approaches that can measure cerebral hemodynamics: (1) optical intrinsic signal imaging, (2) laser speckle imaging, and (3) spatial frequency domain imaging. Future work in advancing widefield optical imaging approaches and employing multimodal instrumentation can enrich hemodynamic information content and help elucidate cerebrovascular mechanisms that lead to the development of therapeutic agents for AD and neurological injury.

Quantifying the confounding effect of pigmentation on measured skin tissue optical properties: a comparison of colorimetry with spatial frequency domain imaging.

SIGNIFICANCE: Spatial frequency domain imaging (SFDI) is a wide-field diffuse optical imaging technique for separately quantifying tissue reduced scattering (µs ' ) and absorption (µa) coefficients at multiple wavelengths, providing wide potential utility for clinical applications such as burn wound characterization and cancer detection. However, measured µs ' and µa can be confounded by absorption from melanin in patients with highly pigmented skin. This issue arises because epidermal melanin is highly absorbing for visible wavelengths and standard homogeneous light-tissue interaction models do not properly account for this complexity. Tristimulus colorimetry (which quantifies pigmentation using the L * "lightness" parameter) can provide a point of comparison between µa, µs ' , and skin pigmentation. AIM: We systematically compare SFDI and colorimetry parameters to quantify confounding effects of pigmentation on measured skin µs ' and µa. We assess the correlation between SFDI and colorimetry parameters as a function of wavelength. APPROACH: µs ' and µa from the palm and ventral forearm were measured for 15 healthy subjects with a wide range of skin pigmentation levels (Fitzpatrick types I to VI) using a Reflect RS® (Modulim, Inc., Irvine, California) SFDI instrument (eight wavelengths, 471 to 851 nm). L * was measured using a Chroma Meter CR-400 (Konica Minolta Sensing, Inc., Tokyo). Linear correlation coefficients were calculated between L * and µs ' and between L * and µa at all wavelengths. RESULTS: For the ventral forearm, strong linear correlations between measured L * and µs ' values were observed at shorter wavelengths (R > 0.92 at ≤659 nm), where absorption from melanin confounded the measured µs ' . These correlations were weaker for the palm (R < 0.59 at ≤659 nm), which has less melanin than the forearm. Similar relationships were observed between L * and µa. CONCLUSIONS: We quantified the effects of epidermal melanin on skin µs ' and µa measured with SFDI. This information may help characterize and correct pigmentation-related inaccuracies in SFDI skin measurements.

Characterizing reduced scattering coefficient of normal human skin across different anatomic locations and Fitzpatrick skin types using spatial frequency domain imaging.

SIGNIFICANCE: Spatial frequency domain imaging (SFDI), a noncontact wide-field imaging technique using patterned illumination with multiple wavelengths, has been used to quantitatively measure structural and functional parameters of in vivo tissue. Using SFDI in a porcine model, we previously found that scattering changes in skin could potentially be used to noninvasively assess burn severity and monitor wound healing. Translating these findings to human subjects necessitates a better understanding of the variation in "baseline" human skin scattering properties across skin types and anatomical locations. AIM: Using SFDI, we aim to characterize the variation in the reduced scattering coefficient (µs') for skin across a range of pigmentation and anatomic sites (including common burn locations) for normal human subjects. These measurements are expected to characterize baseline human skin properties to inform our use of SFDI for clinical burn severity and wound healing assessments. APPROACH: SFDI was used to measure µs' in the visible- and near-infrared regime (471 to 851 nm) in 15 subjects at 10 anatomical locations. Subjects varied in age, gender, and Fitzpatrick skin type. RESULTS: For all anatomical locations, the coefficient of variation in measured µs' decreased with increasing wavelength. High intersubject variation in µs' at visible wavelengths coincided with large values of the melanin extinction coefficient at those wavelengths. At 851 nm, where intersubject variation in µs' was smallest for all anatomical locations and absorption from melanin is minimal, significant intrasubject differences in µs' were observed at the different anatomical locations. CONCLUSIONS: Our study is the first report of wide-field mapping of human skin scattering properties across multiple skin types and anatomical locations using SFDI. Measured µs' values varied notably between skin types at wavelengths where absorption from melanin was prominent. Additionally, µs' varied considerably across different anatomical locations at 851 nm, where the confounding effects from melanin absorption are minimized.

High dose rate brachytherapy as a boost for the treatment of localized prostate cancer.

PURPOSE: We report the outcome and toxicities of high dose rate brachytherapy as a boost for localized prostate cancer. MATERIALS AND METHODS: Between 1996 and 2003, 309 patients with prostate carcinoma were treated with external beam radiation therapy and high dose rate brachytherapy. Furthermore, 36% of the patients received neoadjuvant/concurrent or adjuvant androgen deprivation therapy. Patients were stratified into 3 groups. Group 1 of 67 patients had Gleason score 6 or less, pretreatment prostate specific antigen 10 ng/ml or less and clinical stage T2a or less. Group 2 of 109 patients had Gleason score 7 or greater, pretreatment prostate specific antigen greater than 10 ng/ml and clinical stage T2b or greater. Group 3 of 133 patients had 2 or more of these higher risk factors. RESULTS: At a median followup of 59 months the 5-year biochemical control rate, as defined by the American Society for Therapeutic Radiation and Oncology, was 86%, cause specific survival was 98% and overall survival was 91%. Biochemical control in stratified groups 1 to 3 was 98%, 90% and 78%, respectively. On univariate analysis risk group, pretreatment prostate specific antigen and Gleason score were significant predictors of biochemical control. However, on multivariate analysis only risk group and pretreatment prostate specific antigen were significant. Using the Common Toxicity Criteria scale there were 2 cases of grade 3 acute urinary toxicity. Regarding late side effects 4% of patients had grade 3 genitourinary toxicity and 1 had a grade 4 rectal complication. CONCLUSIONS: External beam radiation therapy and high dose rate brachytherapy for prostate cancer resulted in excellent biochemical control, cause specific survival and overall survival with minimal severe acute or late complications.

The addition of continuous infusion 5-FU to preoperative radiation therapy increases tumor response, leading to increased sphincter preservation in locally advanced rectal cancer.

PURPOSE: To compare the outcome from preoperative chemoradiation (CXRT) and from radiation therapy (RT) in the treatment of rectal cancer in two large, single-institutional experiences. PATIENTS AND METHODS: Between 1978 and 1995, 403 patients with localized, nonmetastatic, clinically staged T3 or T4 rectal cancer patients were treated with preoperative RT alone at two institutions. Patients at institution 1 (n = 207) were treated with pelvic CXRT exclusively, and patients at institution 2 were treated (except for 8 given CXRT) with pelvic RT alone (n = 196). In addition, a third group (n = 61) was treated with CXRT at institution 2 between 1998 and 2000 after a policy change. Both institutions delivered 45 Gy in five fractions as a standard dose, but institution 2 used 20 Gy in five fractions in selected cases (n = 26). At both institutions, concurrent chemotherapy consisted of a continuous infusion of 5-fluorouracil (5-FU) at a dosage of 1500 mg/m(2)/week. The end points were response, sphincter preservation (SP), relapse-free survival (RFS), pelvic disease control (PC), and overall survival (OS). RESULTS: Median follow-up was 63 months for all living patients at institution 1 and in the primary group of institution 2. Multivariate analysis of the patients in these groups showed that the use of concurrent chemotherapy improved tumor response (T-stage downstaging, 62% vs. 42%, p = 0.001, and pathologic complete response, 23% vs. 5% p < 0.0001), but did not significantly improve LC, RFS, or OS. Follow-up for the secondary group at institution 2 was insufficient to allow the analysis of these endpoints. In the subset of patients receiving 45 Gy who had rectal tumors < or /=6 cm from the anal verge (institution 1: n = 132; institution 2 primary: n = 79; institution 2 secondary: n = 33), there was a significant improvement in SP with the use of concurrent chemotherapy (39% at institution 1 compared with 13% in the primary group at institution 2, p < 0.0001). A logistic regression analysis of clinical prognostic factors indicated that the use of concurrent chemotherapy independently influenced SP in these low tumors (p = 0.002). This finding was supported by a 36% SP rate in the secondary group at institution 2. Thus SP increased after the addition of chemotherapy at institution 2. CONCLUSIONS: The use of concurrent 5-FU with preoperative radiation therapy for T3 and T4 rectal cancer independently increases tumor response and may contribute to increased SP in patients with low rectal cancer.

WR-2721 Reduces Intestinal Toxicity from Concurrent Gemcitabine and Radiation Treatment.

The success of radiotherapy as a single treatmentmodality is limited by several factors, including tumor radioresistance due to hypoxia within a tumormass, efficient DNA repair mechanisms, cellularrecovery during the time between radiation fractions,and distant failure from occult tumor cells outsidethe radiation field. For these reasons, radiotherapyis being increasingly combined with other treatmentmodalities, especially chemotherapy. The resultsfrom this type of combined modality treatment haveshown increased local tumor control rates anddecreased distant metastasis (1-4).