Utility of 68Ga-DOTATATE PET-MRI for Gamma Knife® stereotactic radiosurgery treatment planning for meningioma.

OBJECTIVES: To investigate the impact of adding 68Ga-DOTATATE PET/MRI to standard MRI for target volume delineation in Gamma Knife® stereotactic radiosurgery (GKSRS) for meningioma. METHODS: Seventeen patients with 18 lesions undergoing GKSRS for WHO grade 1 meningioma were enrolled in a prospective study. All patients underwent pre-treatment 68Ga-DOTATATE PET/MRI examination in addition to standard procedures. Five clinicians independently contoured the gross tumour volume (GTV) based on standard MRI (GTVMRI) and PET/MRI (GTVPET/MRI) on separate occasions. Interobserver agreement was evaluated using Cohen's Kappa statistic (CKS), Dice similarity coefficient (DC), and Hausdorff distance (HD). Statistical analysis was performed with paired t-test and Wilcoxon signed rank test. RESULTS: The addition of PET/MRI significantly increased GTV contour volume (mean GTVPET/MRI 3.59 cm3 versus mean GTVMRI 3.18 cm3, P = .008). Using the treating clinician's pre-treatment GTVMRI as the reference, median CKS (87.2 vs 77.5, P = .006) and DC (87.2 vs 77.4, P = .006) were significantly lower, and median HD (25.2 vs 31.0, P = .001) was significantly higher with the addition of PET/MRI. No significant difference was observed in interobserver contouring reproducibility between GTVMRI and GTVPET/MRI. CONCLUSION: The addition of 68Ga-DOTATATE PET/MRI for target volume delineation in GKSRS for meningioma is associated with an increase in GTV volume and greater interobserver variation. PET/MRI did not affect interobserver contouring reproducibility. ADVANCES IN KNOWLEDGE: This study provides novel insights into the impact of 68Ga-DOTATATE PET/MRI on GTV delineation and interobserver agreement in meningioma GKSRS, highlighting its potential for improving GKSRS treatment accuracy.

Repurposing traditional U-Net predictions for sparse SAM prompting in medical image segmentation.

Objective:Automated medical image segmentation (MIS) using deep learning has traditionally relied on models built and trained from scratch, or at least fine-tuned on a target dataset. The Segment Anything Model (SAM) by Meta challenges this paradigm by providing zero-shot generalisation capabilities. This study aims to develop and compare methods for refining traditional U-Net segmentations by repurposing them for automated SAM prompting.Approach:A 2D U-Net with EfficientNet-B4 encoder was trained using 4-fold cross-validation on an in-house brain metastases dataset. Segmentation predictions from each validation set were used for automatic sparse prompt generation via a bounding box prompting method (BBPM) and novel implementations of the point prompting method (PPM). The PPMs frequently produced poor slice predictions (PSPs) that required identification and substitution. A slice was identified as a PSP if it (1) contained multiple predicted regions per lesion or (2) possessed outlier foreground pixel counts relative to the patient's other slices. Each PSP was substituted with a corresponding initial U-Net or SAM BBPM prediction. The patients' mean volumetric dice similarity coefficient (DSC) was used to evaluate and compare the methods' performances.Main results:Relative to the initial U-Net segmentations, the BBPM improved mean patient DSC by 3.93 ± 1.48% to 0.847 ± 0.008 DSC. PSPs constituted 20.01-21.63% of PPMs' predictions and without substitution performance dropped by 82.94 ± 3.17% to 0.139 ± 0.023 DSC. Pairing the two PSP identification techniques yielded a sensitivity to PSPs of 92.95 ± 1.20%. By combining this approach with BBPM prediction substitution, the PPMs achieved segmentation accuracies on par with the BBPM, improving mean patient DSC by up to 4.17 ± 1.40% and reaching 0.849 ± 0.007 DSC.Significance:The proposed PSP identification and substitution techniques bridge the gap between PPM and BBPM performance for MIS. Additionally, the uniformity observed in our experiments' results demonstrates the robustness of SAM to variations in prompting style. These findings can assist in the design of both automatically and manually prompted pipelines.

Femoral neck stress fracture return to activity and the effect of metabolic dysfunction on recovery: A systematic review.

Background: Femoral neck stress fractures are rare fractures traditionally found in athletes and military personnel. There is limited literature on return to activity. Objectives: To report return to activity rates and times, and long-term outcomes for femoral neck stress fractures reported in the literature. To examine the effects of bone metabolic dysfunction and surgical management on return to activity following FNSF. Research design & methods: A systematic literature review of case reports and case series on adults with femoral neck stress fracture that were diagnosed by gross fracture line on X-ray or gold-standard diagnosis with MRI was conducted. Initial search was limited to articles published from January 1997 to Jan 2023 listed in Medline, Embase, and Scopus. Additional articles were manually added via search of retained paper sources. Patient demographics, fracture type, return to activity time, and surgical vs non-surgical treatment modality were collected. In addition, long-term outcomes and metabolic effects, if reported, were abstracted. Results: A total of 40 case reports or case series were retained. 123 stress fractures of the femoral neck from 103 patients were compiled. Of the 103 patients, data on return to activity at least one year following treatment was available for 53 patients. 71% (37/53) of those with long-term follow-up information returned to full pre-injury activity. 24% (13/53) at long-term follow-up had functional recovery but did not return to pre-injury activity due to residual pain. 4% (3/53) had disabling pain. Metabolic workup information was available for 36 patients. Conclusion: Long-term follow-up and return to activity information following FNSF treatment are not commonly reported. Based on the available data, outcomes appear benign with most returning to full activity. There is a clear need for standardization of follow-up periods and hip function measure after FNSF treatment. Additionally, a sizable proportion of FNSF occurred in a new population of low-activity individuals with abnormal bone metabolism, which warrants further exploration.

Total Hip Arthroplasty in Nonagenarians - A National In-Patient Sample-Based Study of Perioperative Complications.

Background: Nonagenarians are a rapidly expanding population in the United States. These patients are met with increasing rates of hip arthritis, necessitating the need for total hip arthroplasty (THA). However, there is currently limited information on hospitalization information and perioperative complications in this population. Methods: In this retrospective study, we used the Nationwide Inpatient Sample (NIS) database from 2016-2019 to analyze the incidence of perioperative complications, length of stay (LOS), and the cost of care (COC) among patients undergoing THAs who were categorized as nonagenarians, and those who were not. Results: The NIS database identified 309 100 patients who underwent THAs from 2016-2019. Of those, 1864 patients (.6%) were nonagenarian, while the remaining 307 236 patients were included under the non-nonagenarian category (control). The mean age in the nonagenarian group was 90 years compared to the control group which had a mean age of 65.8 years. There was an increased incidence of mortality rate (nonagenarian group .2%, control group .03%, P < .001), myocardial infarction (MI) (nonagenarian group .1%, control group .02%, P = .01), acute renal failure (ARF) (nonagenarian group 5.4%, control group 1.6%, P < .001), blood anemia post-operatively (nonagenarian group 28.9%, control group 17.2%, P < .001), and deep vein thrombosis (DVT) (nonagenarian group .48%, control group .07%, P < .001) in the nonagenarian group. The COC for the nonagenarian group was higher than that in the control group (P < .001). The mean LOS was longer in the nonagenarian group (3.1 days) in comparison to the control group (1.96 days) (P < .001). Conclusions: Nonagenarians had significantly higher rates of both orthopedics and medical complications than the younger patients undergoing THAs. In addition, the nonagenarian group incurred higher COC. This information is useful for the providers to make informed decisions regarding patient care and resource utilization for nonagenarian patients undergoing THAs.

Comparative Analysis of Unicompartmental Total Knee Arthroplasty and High Tibial Osteotomy: Time to Total Knee Arthroplasty and Other Outcome Measures.

Background: There is no consensus on whether unicompartmental arthroplasty (UKA) or high tibial osteotomy (HTO) is superior for unicompartmental arthritis. While there are studies comparing revision and complication rates, none matched a large number of patients undergoing HTO and UKA in the United States and compared these outcomes. We investigated TKA conversion rate and the complications following HTO or UKA. Methods: This retrospective study queried the PearlDiver database of all patients undergoing UKA and HTO using CPT codes between January 2011 and January 2020. We compared propensity-matched populations based on age, gender, Charlson comorbidity index, and Elixhauser comorbidity index to compare odds of complications, TKA conversion, and drug use between UKA and HTO groups. Two-independent sample t-test for unequal variances and test of significance were performed. Results: We found 32,583 UKA patients and 816 HTO patients. Each matched group had 535 patients. One-year complication showed higher risk of pneumonia, hematoma, infection, and mechanical complications among HTO patients. UKA patients used narcotics on average of 10.3 days compared to 9.1 days among HTO patients (P < .01). UKA conversion rates were 4.1%, 5.4%, 7.7%, and 9.2% at 1-, 2-, 5-, and 10-year intervals, respectively. HTO conversion rates were less than 2% at 1- and 2-year intervals, 3.4% at 5-year, and 4.5% at 10-year intervals. This difference was statistically significant at 5- and 10-year intervals (P < .01). Conclusions: Using large matched cohorts, HTO may be converted to TKA later than UKA in short- to mid-term follow-up, and HTO patients used opioids for shorter duration.

Complications of primary total hip arthroplasty in human immunodeficiency virus-positive patients with femoral head osteonecrosis.

BACKGROUND: Femoral head osteonecrosis (FHON) is a well-recognised complication in patients with human immunodeficiency virus (HIV) infection. Total hip arthroplasty (THA) is a reliable solution to FHON and has provided functional improvement and pain relief in these patients. Higher complication rates, in particular infections, have been reported in the series of THAs done in the HIV-positive patients. The purpose of this study was to evaluate the complication rate of THA for FHON in HIV-positive patients managed with the highly active antiretroviral therapy (HAART) protocols. METHODS: A retrospective review was performed of HIV-positive patients with FHON who underwent THAs over a 10-year period at a single institution. RESULTS: A total of 56 THAs (44 patients) met the inclusion criteria. The mean age at the time of THAs was 47 (range 34-60) years. Of the 44 patients, 39 (88.6%) were males. The mean follow-up was 6.6 (range 2.0-11.3) years. The overall complication rate was 12.5%, with 2 (3.6%) cases of deep periprosthetic infections. CONCLUSIONS: HIV-positive patients with FHON undergoing THAs do have a considerable complication rate (12.5%). The deep periprosthetic infection rate (3.6%) in these patients, however, has decreased with contemporary disease modification protocols.

Effects of Depression, Anxiety, and Pain Catastrophizing on Total Hip Arthroplasty Patient Activity Level.

BACKGROUND: Improvements in psychological factors are strongly associated with increased physical activity in the general population. The effects of depression, anxiety, and pain catastrophizing on activity level have not been thoroughly explored in patients undergoing total hip arthroplasty (THA). Mental health markedly influences patient perspectives on treatment success and quality of life. We hypothesized that improvements in screenings for depression, anxiety, and catastrophizing correlate with improvements in activity levels after THA. METHODS: Two hundred ninety two patients (313 hips) who underwent THA with a minimum 1-year (mean 615 ± 270 days) follow-up completed preoperative and postoperative surveys containing the University of California Los Angeles (UCLA) Activity Score, Hospital Anxiety Depression Scale (HADS), Pain Catastrophizing Scale (PCS), and Depression Anxiety Stress Scale-21 (DASS). Wilcoxon signed-rank tests were performed between preoperative and postoperative times for outcome measures. Partial Spearman's rank-order correlations were performed between the change in UCLA Score and the change in HADS, PCS, and DASS. RESULTS: There were significant improvements in UCLA Score (P value < .0001) and every subscale of PCS, HADS, and DASS (P values < .0001). Significant negative correlations existed between change in UCLA Score and change in HADS-anxiety (rs = -0.21, P value < .001), change in HADS-depression (rs = -0.23, P value < .001), and change in DASS-anxiety (rs = -0.22, P value = .004) following THA. Weaker significant negative correlations existed between change in UCLA Score and change in the remaining PCS (P values = .006) and DASS-depression(P value = .037) subscales. CONCLUSION: Improvements in patient-reported depression, anxiety, and pain catastrophizing screenings following THA were associated with increased activity levels. Patients who were screened for catastrophizing, depression, and anxiety achieved statistically and clinically meaningful improvements in symptoms following THA. Addressing patient mental health provides another avenue for holistic care of THA patients.

Gamma Knife® stereotactic radiosurgery for intracranial cavernous malformations.

INTRODUCTION: Gamma Knife® stereotactic radiosurgery (GKSRS) is a non-invasive alternative to surgical resection for cerebral cavernous malformations (CCMs), especially in eloquent locations. METHODOLOGY: A retrospective review was performed on an Australian cohort of patients receiving GKSRS for CCMs at a single institution. All patients exhibited symptoms and/or radiological evidence of haemorrhage before therapy. The minimum follow-up was 1-year post-GKSRS. McNemar's test was used for differences in matched-pair outcomes pre- and post-GKSRS with an α = 0.05. A systematic review and meta-analysis was additionally performed to synthesise the current published evidence on the clinical efficacy of stereotactic radiosurgery in reducing haemorrhage risk in CCMs using a DerSimonian and Laird random effects model. RESULTS: Thirty-five patients (39 cavernomas) underwent GKSRS. 87.2 % of patients had evidence of at least one haemorrhage before GKSRS and the remainder exhibited seizures. The median dose was 12.5 Gy in a single fraction (IQR 12-13). The median follow-up duration from GKSRS was 809 days (IQR 536-960). There was a significant reduction in matched annual bleed rate from pre-GKSRS (52.1 %) compared to after SRS (12.3 %) (p < 0.001) [OR = 0.07, 95 % 0.008-0.283] There was no statistically significant difference in seizure incidence pre- (30.7 %) versus post-GKSRS (17.9 %) (p = 0.13) [OR = 0.167, 95 %CI 0.004-1.37]. One patient (3 %) with a brainstem lesion experienced long-term treatment-related oedema with persistent ipsilateral weakness and tremors. On meta-analysis of 25 pooled studies, radiosurgery for the treatment of CCMs was associated with a statistically significantly relative risk (RR) reduction in haemorrhage events [random effects RR 0.12 (95 % CI 0.074-0.198), p < 0.001)], with most of the proportionate risk reduction occurring in the initial 2 years following SRS. CONCLUSION: GKSRS significantly reduces the annual rate of haemorrhage for intracranial cavernomas in this cohort and on meta-analysis, particularly in the first 2 years following treatment. The overall risk of treatment-related morbidity is low.

Stereotactic radiosurgery for melanoma brain metastases: Concurrent immune checkpoint inhibitor therapy associated with superior clinicoradiological response outcomes.

INTRODUCTION/PURPOSE: This study assessed long-term clinical and radiological outcomes following treatment with combination stereotactic radiosurgery (SRS) and immunotherapy (IT) for melanoma brain metastases (BM). METHODS: A retrospective review was performed in a contemporary cohort of patients with melanoma BM at a single tertiary institution receiving Gamma Knife® SRS for melanoma BM. Multivariate Cox proportional-hazards modelling was performed with a P <0.05 for significance. RESULTS: 101 patients (435 melanoma BM) were treated with SRS between January-2015 and June-2019. 68.3% of patients received IT within 4 weeks of SRS (concurrent) and 31.7% received SRS alone or non-concurrently with IT. Overall, BM local control rate was 87.1% after SRS. Median progression free survival was 8.7 months. Median follow-up was 29.2 months. On multivariate analysis (MVA), patients receiving concurrent SRS-IT maintained a higher chance of achieving a complete (CR) or partial response (PR) [HR 2.6 (95% CI: 1.2-5.5, P = 0.012)] and a reduced likelihood of progression of disease (PD) [HR 0.52 (95% CI: 0.16-0.60), P = 0.048]. Any increase in BM volume on the initial MRI 3 months after SRS predicted a lower likelihood of achieving long-term CR or PR on MVA accounting for concurrent IT, BRAF status and dexamethasone use [HR = 0.048 (95% CI: 0.007-0.345, P = 0.0026)]. Stratified volumetric change demonstrated a sequential relationship with outcomes on Kaplan-Meier analysis. CONCLUSION: Concurrent SRS-IT has favourable clinical and radiological outcomes with respect to CR, PR and a reduced likelihood of PD. Changes in BM volume on the initial MRI 3 months after SRS were predictive of long-term outcomes for treatment response.

Importance of Cobalt-60 Dose Rate and Biologically Effective Dose on Local Control for Intracranial Meningiomas Treated With Stereotactic Radiosurgery.

BACKGROUND: Radiosurgery dose rate and biologically effective dose (BED) are associated with outcomes after stereotactic radiosurgery (SRS) for functional neurosurgical conditions and some benign tumors. It is not known if these factors affect the efficacy of SRS for meningioma. OBJECTIVE: To determine the association between cobalt-60 dose rate and BED on outcomes in patients with meningioma treated with SRS. METHODS: A single-institution cohort of 336 patients treated between 2005 and 2018 with cobalt-based SRS for 414 separate meningioma lesions was assembled. BED was calculated using an SRS-specific monoexponential model accounting for treatment time per lesion, assuming α/ß = 2.47 Gy. Cumulative incidences of local failure (LF) were reported after considering the competing risk of death, on a per-lesion basis. Multivariable analysis of LF was performed using a proportional hazards model. RESULTS: The most common SRS dose was 12 Gy (n = 227); 140 lesions received 14 Gy. Five-year LF was 15.6% (95% confidence interval 10.4-21.9) and 4.3% (1.4-9.8) in patients who had a dose rate of <2.95 and ≥2.95 Gy/min, respectively (P = .0375). Among 354 grade I or unresected lesions treated with SRS, BED >50 Gy2.47 was associated with a lower incidence of LF (P = .0030). Each 1 Gy/min increase in dose rate was associated with an adjusted hazard ratio of 0.53 (95% confidence interval, 0.29-0.97, P = .041) for LF. Prescription dose >12 Gy was not associated with a lower incidence of LF. CONCLUSION: Patients with meningiomas treated with lower dose rates experienced a higher incidence of LF than those treated with higher dose rates.

Renal Cell Carcinoma Metastasis to Meckel's Cave Treated With Repeat Stereotactic Radiosurgery: A Case Report and Review of the Literature.

Renal cell carcinoma (RCC) metastases to Meckel's cave (MC) are a rare condition. To the best of our knowledge, we present the first case of an RCC metastasis to MC successfully treated on two consecutive occasions with stereotactic radiosurgery (SRS). A 57-year-old man presented with new-onset facial pain and numbness. Magnetic resonance imaging (MRI) revealed a lesion invading MC. He was treated with Gamma Knife SRS successfully, resulting in both symptomatic improvement and radiologic tumour regression. Thirteen months after treatment, he presented with a recurrence of trigeminal nerve symptoms. He was treated with hypofractionated SRS successfully, with a follow-up MRI revealing resolution of the disease. While RCC metastases to MC are a rare phenomenon, published literature to date recommends surgical resection in combination with radiotherapy and systemic therapy. Metastatic disease to MC has only been treated once before with radiosurgery alone. Our case demonstrates that repeat SRS is feasible and efficacious. This approach may be favourable in patients wishing to avoid risks of surgical resection, or for those with unresectable disease. Metastases of RCC to MC are a rare occurrence and typically present with facial pain and/or hypoesthesia. This case demonstrates that repeat radiosurgery may be an effective alternative to surgical resection.

Standardized total knee arthroplasty pathway improves outcomes in minority patients.

OBJECTIVES: Inferior total knee arthroplasty (TKA) outcomes are reported in minority populations. Standardized TKA pathways improve outcomes but have not been studied extensively in minority populations. This study evaluated the impact of TKA pathway standardization at an urban teaching hospital that predominantly treats minority patients. STUDY DESIGN: Retrospective cohort study. METHODS: This study compared primary TKA outcomes before and after implementation of a standardized multidisciplinary pathway that emphasized preoperative education and discharge planning, preemptive multimodal pain control, and early rehabilitation. Patients were grouped as "nonpathway" (n = 144) or "pathway" (n = 182) based on whether they underwent TKA before or after pathway implementation. Outcomes included length of stay (LOS), patient-controlled analgesia (PCA) use, blood transfusion, postoperative hemoglobin, complications, and discharge disposition. Analysis involved negative binomial and multiple logistic regression models, t tests, and Fisher's exact tests. RESULTS: Mean (SD) age was 61.6 (8.7) years, and 36.5% were men. Ethnicity of the patients included Hispanic (44.5%), African American (27.9%), Asian (14.1%), and White (12.9%). Pathway and nonpathway patients were similar demographically and racially. Pathway patients had shorter LOS (P = .04), less PCA use (P < .001), more frequent discharge home (P = .03), fewer transfusions (P = .002), and higher postoperative hemoglobin (P < .001). Overall incidence of complications was similar (P = .61). Nonpathway patients developed more cardiopulmonary complications (P = .02), whereas pathway patients had more wound dehiscence (P = .01). CONCLUSIONS: Compared with nonpathway patients, standardized TKA pathway patients had shorter LOS, decreased PCA use, increased discharge to home, fewer blood transfusions, and higher postoperative hemoglobin, with no difference in total incidence of complication.

Review of patient-reported outcomes in periprosthetic distal femur fractures after total knee arthroplasty: a plate or intramedullary nail?

PURPOSE: This study reviewed the literature regarding the patient-reported treatment outcomes of using either open reduction and internal fixation (ORIF) with a plate and screw system or intramedullary nail (IMN) fixation for periprosthetic distal femur fractures around a total knee arthroplasty. METHODS: A total of 13 studies published in the last 20 years met the inclusion criteria. The studies included 347 patients who were allocated to ORIF (n = 249) and IMN (n = 98) groups according to the implants used. The primary outcome measures were the Knee Society Score or the Western Ontario and McMaster Universities osteoarthritis index. The secondary outcome measures included knee range of motion and the rates of complications, including non-union, malunion, infection, revision total knee arthroplasty, and reoperation. Statistical significance was set at P < 0.05. RESULTS: The mean Knee Society Scores of ORIF and IMN groups were 83 and 84, respectively; the mean postoperative range of motion of the knee were 99° and 100°, respectively (P < 0.05); the non-union rates were 9.4 and 3.8%, respectively (P > 0.05); the malunion rates were 1.8 and 7.5%, respectively (P < 0.05); surgical site infection rates were 2 and 1.3%, respectively (P > 0.05); the reoperation rates were 9.6 and 5.1%, respectively (P > 0.05); and revision rates of total knee arthroplasty were 2 and 1%, respectively (P > 0.05). CONCLUSION: Based on the patient-reported outcome assessments, both ORIF with a plate and screw system and IMN fixation are well-accepted techniques for periprosthetic distal femur fractures around a TKA, and they produce similar functional outcomes.

Stereotactic radiotherapy for large vestibular schwannomas: Volume change following single fraction versus hypofractionated approaches.

Hypofractionated stereotactic radiotherapy is a treatment option for large vestibular schwannomas supported by an increasing evidence. A single institution retrospective review of large (>3.5cc) vestibular schwannomas treated with hypofractionated stereotactic radiotherapy and single-session radiosurgery was conducted. Using serial follow up scans, a volumetric analysis of tumor volume change over time was performed. Vestibular schwannomas treated with hypofractionated stereotactic radiotherapy appeared to reduce in volume significantly faster than those treated with single-session radiosurgery. Cystic lesions reduced in volume faster than solid lesions. There was no significant difference in the rates of radiological and symptomatic oedema, nor subsequent dexamethasone requirement between the two treatment modalities.

Efficacy of stereotactic radiosurgery for radiation-induced meningiomas.

PURPOSE: Stereotactic radiosurgery is an established treatment option for sporadic meningiomas, though limited data exists for radiation-induced lesions. METHODS: Patients treated with cobalt-60 radiosurgery between October 2005 and December 2018 in an institutional registry were reviewed. Single fraction treatments were prescribed to the 50% isodose line. Lesions were deemed to be radiation-induced according to standard criteria previously established by Cahan et al. RESULTS: A total of 37 patients with 72 lesions were analysed. Median follow up per patient was 44 months (range, 1.4-150.7 months). Median age at initial radiotherapy was 5 years (4 months-48 years), and at radiosurgery was 38 years. Of the 72 lesions, 62 were grade 1 (n = 4) or radiologically-diagnosed (n = 58), six were grade 2 and four were grade 3. Median lesion volume was 2.13 cc (0.04-13.8 cc), while the median radiosurgery margin dose was 13 Gy. Local control, on a per lesion basis, was 88.6% at 5 years (95% confidence interval [CI] 72.3-95.6). For grade 1 or radiologically-diagnosed lesions, local control was 96.6% at 5 years (95% CI 77.9-99.5), whereas those with grade 2 or higher lesions had a local control of 40% at 5 years (95% CI 5.2-75.3, p = 0.005). Radiologic oedema developed in 17 lesions (23.6%) and was symptomatic in 12 patients (16.7%). Doses above 12 Gy were not associated with local control probability (p = 0.292). CONCLUSION: Radiosurgery is an effective treatment option for grade 1 or radiologically-diagnosed radiation-induced meningiomas, with 12 Gy appearing to be a sufficient dose.

Sources of contamination in the operating room: A fluorescent particle powder study.

This study utilized fluorescent particle powder to investigate 2 potential sources of sterile field contamination in the operating room (OR): forced-air warming blankets and OR light manipulation. In part 1, sterile draping for knee replacement surgery was performed on a mannequin in a sterile OR, comparing field contamination with the forced-air warming on versus off during draping. In part 2, OR lights coated with fluorescent powder were manipulated over a sterile field. Proper operation of these devices may reduce the particle burden on the surgical field.

Evidence of dose-response following hypofractionated stereotactic radiotherapy to the cavity after surgery for brain metastases.

BACKGROUND AND OBJECTIVE: A retrospective review of consecutive patients between January 2012 and December 2018 receiving hypofractionated stereotactic radiotherapy (HSRT) to the cavity after resection for brain metastases was performed. METHODS: Treatment was delivered using an appropriately commissioned linear accelerator. The primary outcome was time to radiological or histological confirmation of local recurrence following completion of HSRT. Dose-fractionation regimens were converted to biologically 2 Gy-equivalent doses assuming α/ß = 10 (EQD2[10]). Multivariate Cox proportional hazards modelling was performed to determine hazard ratios (HR) with respective 95% confidence intervals (CI). The Log-rank test was used to determine p values taking statistical significance p < 0.05. RESULTS: There were 134 patients and 144 cavities identified. The most common primary histologies were melanoma (n = 49) and lung (n = 32). 116 patients (87%) underwent a gross total resection. Median planning target volume (PTV) was 28 cm3 (range 2.4-149.2). Median EQD2[10] was 38.4 Gy (range 22.3-59.7) and 24 Gy in 3 fractions was the most common regimen. 12 (9%) patients demonstrated local recurrence at median interval 215 days (range 4-594). 7 (5%) patients experienced grade 3 or higher toxicities. In multivariate analysis, EQD2[10] was associated with local failure such that increased equivalent doses improved local control [HR = 0.79 and 95% CI 0.65-0.96, p = 0.0192]. There were no significant associations for primary histology, patient age, volume of residual disease, PTV volume or location. CONCLUSION: This large series demonstrates that HSFRT to the surgical resection cavity for brain metastases has improved local control with increasing dose. Rates of grade 3 or higher toxicity were low overall.

The prevalence and morphological characteristics of the knee anterolateral ligament in a Chinese population.

The anterolateral ligament, a distinct structure connecting the lateral femoral epicondyle to the anterolateral proximal tibia, is gaining attention because of its possible function in ensuring internal rotational stability of the tibia. To study the prevalence and precise anatomical characteristics of the anterolateral ligament and its relationship to adjacent structures in a Chinese population, a total of 20 amputated knee specimens were collected. The anterolateral regions of the knees underwent detailed surgical dissection, followed by precise measurement of the anterolateral ligament and its adjacent structures. Histological analysis of the anterolateral ligament was performed using hematoxylin and eosin (H&E) staining. A thin soft tissue deep to the iliotibial band running obliquely across the lateral fibula ligament and connecting the lateral head of the gastrocnemius with the tibia, termed the 'gastrocnemius-tibial ligament' or superficial layer of the anterolateral ligament, was observed in 18 of the 20 specimens, corresponding to a prevalence of 90%. Furthermore, a well-defined anterolateral ligament deep to the gastrocnemius-tibial ligament and distinct from the lateral fibula ligament was found in all 20 knees (prevalence, 100%). The independent gastrocnemius-tibial ligament and anterolateral ligament had separate femoral originations at the lateral head of the gastrocnemius and the lateral femoral epicondyle, and the same osseous tibial insertion at the midpoint between Gerdy's tubercle and the most lateral aspect of the fibular head. H&E staining showed that both the anterolateral ligament and gastrocnemius-tibial ligament were ligaments consisting of collagenous bundles. In the Chinese Han population, the gastrocnemius-tibial ligament and anterolateral ligament may form a complex at the anterolateral aspect of the knee, which is likely involved in ensuring the internal rotational stability of the tibia.

Venous Thromboembolism Prophylaxis after Total Knee Arthroplasty.

Venous thromboembolic disease (VTED) is a major cause of morbidity and mortality after total knee arthroplasty (TKA). Current VTED prophylaxis protocols consist of early mobilization, mechanical compression devices, and pharmacologic agents. Venous phasic flow-regulated below-knee devices are generally favored, but the optimal duration and method of mechanical prophylaxis is unknown. Risk stratification models have been developed to guide pharmacologic prophylaxis. For patients with standard VTED risk profile, aspirin has become increasingly popular. Recent studies have validated the efficacy, relatively low bleeding risks, and cost-effectiveness of aspirin in the patients with standard risk profile. Current evidence suggests that the newer oral anticoagulants, including the factor Xa and the direct thrombin inhibitors, are effective for the reduction of postoperative VTED but may be associated with increased bleeding and wound complication rates.