Extra axial bone ablation with augmentation.

Pelvic bone metastases frequently result in severe pain and disability. Open surgical reconstruction is associated with a high complication and mortality rate. Percutaneous screw fixation is a minimally invasive treatment that is safe and effective for the management of periacetabular metastases. This article details our technique for pelvic screw fixation, including (1) perioperative care, (2) navigation and needle guidance, (3) access, (4) biopsy and ablation, (5) screw placement, and (6) cement augmentation.

Keeping it "straight": how to do spinal tumor ablation with vertebral augmentation.

This technical review provides a comprehensive overview of spinal tumor ablation and vertebral augmentation. These percutaneous minimally invasive procedures offer significant survival and palliative pain relief benefits for patients with pathological vertebral fractures. Vertebral augmentation, which includes vertebroplasty and kyphoplasty, involves injecting cement into fractured vertebral bodies to restore height. While vertebroplasty involves the direct injection of cement into a fractured vertebral body, kyphoplasty involves using a balloon to create a low-pressure cavity to allow for cement injection to restore the vertebral body height. Over the years, this technique has evolved into a straightforward process, though it presents certain technical challenges discussed in this article.

Machine Learning Model Based on Prognostic Nutritional Index for Predicting Long-Term Outcomes in Patients With HCC Undergoing Ablation.

AIMS: To develop multiple machine learning (ML) models based on the prognostic nutritional index (PNI) and determine the optimal model for predicting long-term survival outcomes in hepatocellular carcinoma (HCC) patients after local ablation. METHODS: From January 2009 to December 2019, we analyzed data from 848 primary HCC patients who underwent local ablation. ML models were constructed and evaluated using the concordance index (C-index), concordance-discordance area under curve (C/D AUC), and Brier scores. The optimal ML model was interpreted using the partial dependence plot (PDP) and SHapley Additive exPlanations (SHAP) framework. Additionally, the prognostic performance of our model was compared with other models. RESULTS: Alkaline phosphatase, preoperation alpha-fetoprotein level, PNI, tumor number, and tumor size were identified as independent prognostic factors for ML model construction. Among the 19 ML algorithms tested, the Aorsf model showed superior performance in both the training cohort (C/D AUC: 0.733; C-index: 0.736; Brier score: 0.133) and validation cohort (C/D AUC: 0.713; C-index: 0.793; Brier score: 0.117). The time-dependent AUC of the Aorsf model for predicting overall survival was as follows: 1-, 3-, 5-, 7-, and 9-year were 0.828, 0.765, 0.781, 0.817, and 0.812 in the training cohort, 0.846, 0.859, 0.824, 0.845, and 0.874 in the validation cohort, respectively. The PDP and SHAP algorithms were employed for visual interpretation. Furthermore, time-AUC and decision curve analysis demonstrated that the Aorsf model provided superior clinical benefits compared to other models. CONCLUSION: The PNI-based Aorsf model effectively predicts long-term survival outcomes after ablation therapy, making a significant contribution to HCC research by improving surveillance, prevention, and treatment strategies.

Brazilian Consensus on the Application of Thermal Ablation for Treatment of Thyroid Nodules: A Task Force Statement by the Brazilian Society of Interventional Radiology and Endovascular Surgery (SOBRICE), Brazilian Society of Head and Neck Surgery (SBCCP), and Brazilian Society of Endocrinology and Metabolism (SBEM).

There is increasing interest in ultrasound-guided ablation treatments for thyroid diseases, including benign and malignant ones. Surgeons, radiologists, and endocrinologists carry out these treatments, and various organizations within these specialties have recently released multiple international consensus statements and clinical practice standards. The aim of the present consensus statement is to provide guidance, cohesion, and standardization of best practices for thermal ablation procedures of thyroid nodules. The statement includes the indications for these procedures, preprocedural evaluations, technical aspects of the procedures, posttreatment care, follow-up, complications, and training recommendations. This document was written by a panel of specialists from the Brazilian Society of Interventional Radiology and Endovascular Surgery (SOBRICE), the Brazilian Society of Head and Neck Surgery (SBCCP), and the Brazilian Society of Endocrinology and Metabolism (SBEM). The statement does not aim to provide criteria for assessing the capability of specialists to perform the procedure. Instead, it aims to promote the standardization of best practices to reduce potential adverse outcomes. Additionally, it strives to enhance the delivery of high-quality care and the widespread adoption of these technologies on a national level. The recommendations collectively serve as a guidebook for applying best practices in thyroid ablation.

Utilizing artificial neural network system to predict the residual valve after endoscopic posterior urethral valve ablation.

PURPOSE: To build, train, and assess the artificial neural network (ANN) system in estimating the residual valve rate after endoscopic valve ablation and compare the data obtained with conventional analysis. METHODS: In a retrospective cross-sectional study between June 2010 and December 2020, 144 children with a history of posterior urethral valve (PUV) who underwent endoscopic valve ablation were enrolled in the study. MATLAB software was used to design and train the network in a feed-forward backpropagation error adjustment scheme. Preoperative and postoperative data from 101 patients (70%) (training set) were utilized to assess the impact and relative significance of the necessity for repeated ablation. The validated suitably trained ANN was used to predict repeated ablation in the next 33 patients (22.9%) (test set) whose preoperative data were serially input into the system. To assess system accuracy in forecasting the requirement for repeat ablation, projected values were compared to actual outcomes. The likelihood of predicting the residual valve was calculated using a three-layered backpropagating deep ANN using preoperative and postoperative information. RESULTS: Of 144 operated cases, 33 (22.9%) had residual valves and needs to repeated ablation. The ANN accuracy, sensitivity, and specificity for predicting the residual valve were 90.75%, 92.73%, and 73.19%, respectively. Younger age at surgery, hyperechogenicity of the renal parenchyma, presence of vesicoureteral reflux (VUR), and grade of reflux before surgery were among the most significant characteristics that affected postoperative outcome variables, the need for repeated ablation, and were given the highest relative weight by the ANN system.  Conclusions: The ANN is an integrated data-gathering tool for analyzing and finding relationships among variables as a complex non-linear statistical model. The results indicate that ANN is a valuable tool for outcome prediction of the residual valve after endoscopic valve ablation in patients with PUV.

[Expert consensus on the perioperative management of co-ablation system therapy of lung tumors].

In order to improve the quality of clinical therapy and nursing care for patients with lung tumors undergoing Co-Ablation System and standardize perioperative management, the Committee of Ablation Therapy in oncology, Chinese Anti-Cancer Association, and the Expert committee on Ablation Therapy and the Committee of Interventional Perioperative, Interventional Physician Branch of Chinese Medical Doctor Association organized medical and nursing experts in China. Based on the clinical practice of Co-Ablation System therapy in China and relevant domestic literature, a perioperative management expert consensus was developed. The expert consensus included the key points of perioperative nursing care, prevention and intervention of complications, and discharge guidance for Co-Ablation System therapy of lung tumors, to provide reference for the standardization and development of clinical management for lung tumors.

Mathematical 3D Liver Model for Surgical versus Ablative Therapy Treatment Planning for Colorectal Liver Metastases: Recommendations from the COLLISION and COLDFIRE Trial Expert Panels.

Purpose To further define anatomic criteria for resection and ablation using an expert panel-based three-dimensional liver model to objectively predict local treatment recommendations for colorectal liver metastases (CRLM). Materials and Methods This study analyzed data from participants with small CRLM (≤3 cm) considered suitable for resection, thermal ablation, or irreversible electroporation (IRE), according to a multidisciplinary expert panel, who were included in two prospective multicenter trials (COLLISION [NCT03088150] and COLDFIRE-2 [NCT02082782]) between August 2017 and June 2022. Ten randomly selected participants were used to standardize the model's Couinaud segments. CRLM coordinates were measured and plotted in the model as color-coded lesions according to the treatment recommendations. Statistical validation was achieved through leave-one-out cross-validation. Results A total of 611 CRLM in 202 participants (mean age, 63 [range, 29-87] years; 138 male and 64 female) were included. Superficially located CRLM were considered suitable for resection, whereas more deep-seated CRLM were preferably ablated, with the transition zone at a subsurface depth of 3 cm. Ninety-three percent (25 of 27) of perihilar CRLM treated with IRE were at least partially located within 1 cm from the portal triad. Use of the model correctly predicted the preferred treatment in 313 of 424 CRLM (73.8%). Conclusion The results suggest that CRLM can be defined as superficial (preferably resected) and deep-seated (preferably ablated) if the tumor center is within versus beyond 3 cm from the liver surface, respectively, and as perihilar if the tumor margins extend to within 1 cm from the portal triad. Keywords: Ablation Techniques, CT, MRI, Liver, Abdomen/GI, Metastases, Oncology Supplemental material is available for this article. © RSNA, 2024.

Procedural Volume and Outcomes After Septal Reduction Therapies in Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND: Septal myectomy and alcohol septal ablation (ASA) are septal reduction therapies for patients with symptomatic obstructive hypertrophic cardiomyopathy. Operator and hospital volume may influence outcomes, but contemporary data on this relationship are limited. METHODS AND RESULTS: This retrospective cohort study used data from the Vizient Clinical Data Base (2016-2022). Patients with undergoing septal myectomy and ASA were identified using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes and stratified into low-, medium-, and high-volume groups based on annualized operator and hospital volumes. The outcomes were 30-day in-hospital mortality and 90-day readmission, analyzed using multivariable adjusted logistic and Cox models. Among 5725 patients with hypertrophic cardiomyopathy (3990 septal myectomy; 1735 ASA), most operators and hospitals performed <10 procedures annually. For septal myectomy, low-volume operators were associated with higher odds of 30-day mortality (adjusted odds ratio [aOR], 1.86 [95% CI, 1.11-3.15]) and greater risk for 90-day readmission (aOR, 1.51 [95% CI, 1.22-1.88]), and medium-volume operators had higher odds of 30-day mortality (aOR, 1.93 [95% CI, 1.05-3.55]). Medium-volume hospitals had higher 30-day mortality (aOR, 2.29 [95% CI, 1.32-3.99]), with low-volume hospitals showing greater risk for 90-day readmission (aOR, 1.60 [95% CI, 1.14-2.23]). For ASA, low- and medium-volume operators had increased 30-day mortality (aOR, 2.99 [95% CI, 1.15-7.75] and aOR, 3.86 [95% CI, 1.30-11.46]), but the risk of 90-day readmission was similar. Hospital volumes did not significantly impact outcomes for ASA. CONCLUSIONS: Low operator and hospital volumes were associated with worse outcomes for septal reduction therapies, emphasizing the need to refer patients with hypertrophic cardiomyopathy to high-volume centers with experienced operators.

Effect of Microwave Ablation Power and Antenna Approach on Tumor Seeding: An Ex Vivo Subcapsular Tumor Model Study.

OBJECTIVE: To evaluate the effects of microwave (MW) power and antenna approach methods on extrahepatic tumor seeding and ablation zone size using an ex vivo subcapsular tumor-mimic model. MATERIALS AND METHODS: Forty-one subcapsular tumor mimics were prepared by injecting a mixture of contrast media into bovine liver blocks. Ablation was performed using low- and high-power protocols (75 W and 100 W for 4 and 3 minutes, respectively). The antenna approach was assessed in two directions: parallel and perpendicular to the capsule. CT scans were obtained before and after the ablation to detect contrast leakage on the hepatic surface. The presence of leakage, ablation zone size, and the timing of the first popping sound were compared between the two groups. RESULTS: Five cases of contrast leakage were observed in the low-power group (n = 21) and 17 in the high-power group (n = 20) (23.8% vs. 85.0%, P < 0.001). Contrast leaks were less frequently observed in the low-power protocol compared to the high-power protocol, regardless of the antenna approach (18.2% [2/11] vs. 80.0% [8/10], P = 0.009 for parallel access; 30.0% [3/10] vs. 90.0% [9/10], P = 0.020 for perpendicular access). The timing of the first popping sound was significantly delayed in the low-power group compared to the high-power group (137.7 ± 51.4 s vs. 77.8 ± 31.4 s, P < 0.001). The size of the ablation zone did not differ significantly between the two power groups (P = 0.415). The parallel and perpendicular antenna approaches did not show significant differences in the number of contrast leaks, popping sound timing, or ablation-zone size (P = 0.536, 0.463, and 0.271, respectively). CONCLUSION: Low-power MW ablation may be superior to a high-power protocol in reducing the risk of tumor seeding in subcapsular tumors, regardless of the antenna approach.

Successful laparotomic ethanol ablation for an adrenal tumour in a dog.

Adrenalectomy is the gold standard for canine adrenal tumours, but not always recommended due to patient age, underlying conditions and perioperative mortality. Ethanol ablation is an alternative in human medicine for poor surgical candidates. A 13-year-old neutered female toy-poodle with hypercortisolism presented with severe haematuria. Ultrasonography revealed left adrenal and right kidney tumours. Due to high surgical risk, simultaneous laparotomic right nephroureterectomy and ethanol ablation of the left adrenal tumour were performed. Post-ethanol injection complications included transient hypertension and arrhythmia, which resolved spontaneously. The adrenal tumour size decreased within 2.5 months, and cortisol levels normalised within 8 days, remaining stable for 12 months. No hypercortisolism signs were observed without trilostane until death from renal insufficiency. Autopsy showed that the ablated left adrenal gland was an adrenocortical tumour and had shrunk. Ethanol ablation may be a feasible alternative to adrenalectomy for high-risk canine patients.

Investigating the optimal maximum diameter of benign thyroid nodules for thermal ablation on the basis of complete disappearance rate.

OBJECTIVE: Thermal ablation (TA) is a safe and effective treatment for benign thyroid nodules (BTNs). However, there has been no consensus on the optimal maximum diameter (MD) of BTNs for TA. This study aimed to identify the optimal MD of BTNs for TA based on complete disappearance rate after TA. MATERIALS AND METHODS: This retrospective study included 639 BTNs treated with TA from June 2014 to January 2022. The complete disappearance rate of BTNs after TA was summarized, related influencing factors were explored, and the optimal MD of BTNs for TA was identified. RESULTS: At the final follow-up (median: 40 months, range: 24-95 months), the overall volume reduction rate was 95.4 ± 9.0%, and 50.5% of the BTNs (323/639) completely disappeared. The MD was significantly negatively correlated with complete disappearance (odds ratio 0.89, 95% confidence interval 0.87-0.92; p < 0.001). Calcification, comet-tail artifacts, multilocular cysts, and composition of BTNs, as well as diabetes were negatively correlated with complete disappearance. Restricted cubic spline indicated that an MD of 25.0 mm was the optimal threshold of BTNs for TA, which was confirmed by subgroup logistic regression analysis. Compared with BTNs with MD ≤ 25.0 mm, those with MD > 25.0 mm had a greater complication rate (6.5% vs. 2.4%, p = 0.012). CONCLUSIONS: The MD of BTNs was negatively correlated with complete disappearance after TA; an MD > 25.0 mm indicated a reduced likelihood of complete disappearance compared with an MD ≤ 25.0 mm. An MD of 25.0 mm is an appropriate threshold of BTNs for TA on the basis of complete disappearance rate.

Clinical observation of low temperature plasma ablation combined with collagenase injection in lumbar disc herniation.

To observe the effect of low temperature plasma ablation combined with collagenase injection on lumbar disc herniation. 90 patients with lumbar disc herniation admitted to the pain department of our hospital and receiving surgical treatment from April 2021 to April 2023 were included in this retrospective study, and were divided into 2 groups according to different treatment plans. One group was treated with low-temperature plasma ablation combined with collagenase injection, and the other group was treated with low-temperature plasma ablation alone. The sample size of both groups was 80 cases. Peripheral blood was collected by fasting in the morning at 5 time points before surgery, 1, 3, 7 and 14 days after surgery, and 5 mL of whole venous blood was collected by disposable vacuum blood collection device. Serum levels of pro-inflammatory factor interleukin (IL)-1α, IL-1ß, IL-6, IL-8, tumor necrosis factor-α and anti-inflammatory factor IL-4, IL-10 were detected by ELISA. VAS scores were used to evaluate postoperative low back pain. ODI and Lehmann Lumbar Function Scale were used to evaluate postoperative lumbar function. The contents of IL-1α, IL-1ß, IL-6, IL-8, tumor necrosis factor-α and anti-inflammatory factor IL-4, IL-10 in the cryo-plasma ablation combined with collagenase injection group were significantly lower than those in the cryo-plasma ablation group alone (P < .05). The VAS score of cryo-plasma ablation combined with collagenase injection group was significantly lower than that of cryo-plasma ablation group at 1 day and 3 months after treatment, and the difference was statistically significant (P < .05). The ODI score of cryo-plasma ablation combined with collagenase injection group was significantly lower than that of cryo-plasma ablation group at 1 day and 3 months after treatment, and the difference was statistically significant (P < .05). The Lehmann score of cryo-plasma ablation combined with collagenase injection group was significantly higher than that of cryo-plasma ablation group at 1 day and 3 months after treatment, and the difference was statistically significant (P < .05). The overall efficacy of low-temperature plasma ablation combined with collagenase injection is better than that of low-temperature plasma ablation alone. Low temperature plasma ablation combined with collagenase injection in the treatment of patients with lumbar disc herniation has less pain, faster recovery.

Augmented Reality Navigation System (SIRIO) for Neuroprotection in Vertebral Tumoral Ablation.

(1) This study evaluates the impact of the CT-guided SIRIO augmented reality navigation system on the procedural efficacy and clinical outcomes of neuroprotection in vertebral thermal ablation (RTA) for primary and metastatic bone tumors. (2) Methods: A retrospective non-randomized analysis of 28 vertebral RTA procedures was conducted, comparing 12 SIRIO-assisted and 16 non-SIRIO-assisted procedures. The primary outcomes included dose-length product (DLP) and epidural dissection time. The secondary outcomes included technical success, complication rates, and pain scores at procedural time (VAS Time 0) and three months post-procedure (VAS Time 1). The statistical analyses included t-tests, Mann-Whitney U tests, and multiple regression. (3) Results: SIRIO-assisted procedures significantly reduced DLP (307.42 mGycm vs. 460.31 mGycm, p = 2.23 × 10-8) and procedural epidural dissection time (13.48 min vs. 32.26 min, p = 2.61 × 10-12) compared to non-SIRIO-assisted procedures. Multiple regression confirmed these reductions were significant (DLP: ß = -162.38, p < 0.001; time: ß = -18.25, p < 0.001). Pain scores (VAS Time 1) did not differ significantly between groups, and tumor type did not significantly influence outcomes. (4) Conclusions: The SIRIO system enhances neuroprotection efficacy and safety, reducing radiation dose and procedural time during spine tumoral ablation while maintaining consistent pain management outcomes.

Surgical Ablative Therapies in Patients With Radiorecurrent Prostate Cancer.

Management of recurrent prostate cancer following radiotherapy and subsequent radical prostatectomy poses considerable challenges due to potential complications for patients. Focal therapies have emerged as a burgeoning approach in prostate cancer treatment. Research indicates that ablative therapies exhibit encouraging oncological efficacy while maintaining acceptable functional outcomes in salvage interventions. Here, we present a contemporary review of focal therapy treatment modalities as well as oncologic and functional outcomes.

Efficacy and safety of microwave ablation for treatment of follicular thyroid neoplasms: a preliminary study.

OBJECTIVE: To assess the feasibility, efficacy, and safety of microwave ablation in treating follicular thyroid neoplasms and suspicious follicular thyroid neoplasms. METHODS: In this retrospective study, the data of patients treated with microwave ablation for follicular neoplasms from December 2016 to January 2024 were summarized. The changes in nodule size, volume, technical success rate, disease progression, complete tumor resolution, thyroid function, and complications post-ablation were evaluated. RESULTS: Seventy-four patients (15 men, 59 women; mean age 46.3 ± 15.2 years) with follicular neoplasms were included. Over a median follow-up of 13 months, complete ablation was achieved, giving a 100% technical success rate. At the first month post-ablation, the maximum diameter of nodules showed no significant change (p = 0.287). From the third month, both maximum diameter and volume significantly decreased (p < 0.005 for all). Volume reduction rates remained stable at one and three months (p = 0.389 and 0.06, respectively) but increased significantly thereafter (p < 0.005 for all). By 24 months, the median maximum diameter had reduced from 2.3 cm to 0 cm, achieving a median volume reduction rate of 100%. Nodules disappeared completely in 20.3% (15/74). Local recurrence was noted in 2.7% of cases (2/74), with no metastasis or neoplasm-related deaths reported. Thyroid function remained unchanged post-treatment (p > 0.05). The complication and side effect rates were 8.1% and 4.1%, respectively. CONCLUSIONS: Initial findings suggest microwave ablation is an effective and safe treatment for follicular neoplasms, with low incidences of disease progression and complications, while maintaining thyroid function.

Oncologic Outcomes after Percutaneous Ablation for Colorectal Liver Metastases: An Updated Comprehensive Review.

Colorectal cancer is a major cause of cancer-related mortality, with liver metastases occurring in over a third of patients, and is correlated with poor prognosis. Despite surgical resection being the primary treatment option, only about 20% of patients qualify for surgery. Current guidelines recommend thermal ablation either alone or combined with surgery to treat limited hepatic metastases, provided that all visible disease can be effectively eradicated. Several ablation modalities, including radiofrequency ablation, microwave ablation, cryoablation, irreversible electroporation and histotripsy, are part of the percutaneous ablation armamentarium. Thermal ablation, including radiofrequency, microwave ablation and cryoablation, can offer local tumor control rates comparable to limited resection for selected tumors that can be ablated with margins. This review aims to encapsulate the current clinical evidence regarding the efficacy and oncologic outcomes after percutaneous ablation for the treatment of colorectal liver metastatic disease.

The Paradox of Modern Technology in Standardizing Thermal Liver Ablation: Fostering Uniformity or Diversity?

PURPOSE: Currently, significant medical practice variation exists in thermal ablation (TA) of malignant liver tumors with associated differences in outcomes. The IMaging and Advanced Guidance for workflow optimization in Interventional Oncology (IMAGIO) consortium aims to integrate interventional oncology into the standard clinical pathway for cancer treatment in Europe by 2030, by development of a standardized low-complex-high-precision workflow for TA of malignant liver tumors. This study was conducted at the start of the IMAGIO project with the aim to explore the current state and future role of modern technology in TA of malignant liver tumors. MATERIALS AND METHODS: A cross-sectional questionnaire was conducted followed by an expert focus group discussion with core members and collaborating partners of the consortium. RESULTS: Of the 13 participants, 10 respondents filled in the questionnaire. During the focus group discussion, there was consensus on the need for international standardization in TA and several aspects of the procedure, such as planning based on cross-sectional images, the adoption of different techniques for needle placement and the importance of needle position- and post-ablative margin confirmation scans. Yet, also considerable heterogeneity was reported in the adoption of modern technology, particularly in navigational systems and computer-assisted margin assessment. CONCLUSION: This study mirrored the current diversity in workflow of thermal liver ablation. To obtain comparable outcomes worldwide, standardization is needed. While advancements in tools and software hold the potential to homogenize outcome measurement and minimize operator-dependent variability, the rapid increase in availability also contributes to enhanced workflow variation.

Gamma-glutamyl transferase to aspartate aminotransferase ratio (GSR) predicts prognoses in patients with colorectal cancer with liver metastasis after microwave ablation.

BACKGROUND: Microwave ablation (MWA) is widely used to eliminate colorectal liver metastases (CRLM). However, the risk of tumor recurrence is difficult to predict due to lack of reliable clinical and biological markers. Elevation of gamma-glutamyl transferase (GGT) and aspartate transaminase (AST) provides signals for liver inflammation and cancer progression. The present study evaluated the association between pre-ablation GGT to AST ratio index (GSR) and hepatic recurrence in patients with CRLM after MWA. METHODS: A retrospectively analyzed 192 CRLM patients who underwent MWA from January 2013 to December 2017. Pre-ablation GSR was classified into high (≤ 2.34) or low (> 2.34) using the upper quartile value. The prognostic value of GSR and other risk factors for liver progression-free survival (LPFS) and cancer-specific survival (CSS) were evaluated by univariate and multivariate analyses. RESULTS: High GSR was significantly associated with males (P = 0.041), the presence of cholelithiasis (P = 0.012), but not pre-ablation chemotherapy (P = 0.355), which caused significantly increased levels of GGT (P = 0.015) and AST (P = 0.008). GSR showed a significant association with LPFS and CSS through univariate analysis (P = 0.002 and 0.006) and multivariate analysis (P = 0.043 and 0.037). The subgroup analysis demonstrated no interaction between GSR and all variables except for distribution in the sub-analysis of LPFS. CONCLUSIONS: Our findings suggest that the pre-ablation GSR can be considered as a promising prognostic indicator for poor prognosis of patients with CRLM underwent MWA. TRIAL REGISTRATION: Not applicable.