Clinicopathological features and surgical procedures of adnexal masses with abdominal pain in pediatric and adolescent patients.

PURPOSE: This study investigated the clinicopathological features and surgical procedures of adnexal masses with abdominal pain in pediatric and adolescent patients. Our objective was to better define the clinical presentation of adnexal torsion and to distinguish characteristics of those with torsion and those with an alternate diagnosis. METHODS: Retrospective cohort study of 212 pediatric and adolescent patients was performed who admitted for abdominal pain and presenting with an adnexal mass between March 2012 to December 2019.Medical records were reviewed for age at operation, including presentation of symptoms and signs; the levels of tumor markers; imaging examinations; pathologic findings; the size of masses; treatment; and outcome. Data management and descriptive analyses were performed using SPSS 26.0. RESULTS: The median age of the patients was 14.5 ± 3.6 years at the operation. 126 (59.4%, 126/212) patients presented with an abrupt onset of abdominal pain. A total of 82.1% (174/212) of the participants underwent adnexal conservative surgery. 179 (84.5%, 179/212) patients underwent laparoscopic surgery with an average tumor size of 7.7 ± 3.4 cm, while 33 patients ( 15.6%, 33/212) underwent laparotomy. Rupture of mass and ectopic pregnancy accounted for 7.5% (16/212) and 0.9%(2/212), respectively. Torsion was responsible for 36.8% (78/212) of all patients. Among the patients with torsion, the symptom of nausea and vomiting was more common among girls without torsion (P < 0.0001). 88.5% of the girls with torsion had acute onset of abdominal pain, while 92.3% had persistent pain that could not be relieved or occurred repeatedly, which significantly higher than that in the patients without torsion (P < 0.001). 69.2% of patients with torsion had fixed pain sites, compared with 42.2% in patients without torsion (P < 0.001). 88.5% of girls with torsion had an ovarian cyst/mass ≥ 5 cm, compared with 75.0% in girls without torsion (P = 0.038). 66.7% of girls underwent ovary-preserving surgery, compared with 92.2% in patients without torsion. The most common pathologic types were mature teratoma and simple cyst, accounting for 29.4% and 25.6%, respectively. The multivariate analyses confirmed that mass size greater than 5 cm (OR 4.134, 95% CI: 1.349-12.669,P = 0.013), acute onset pain (OR 24.150,95%CI: 8.398-69.444,P = 0.000), persistent or recurrent pain (OR 15.911,95%CI: 6.164-41.075,P = 0.000) were significantly associated with increased risk of torsion. CONCLUSIONS: Torsion which is a relatively rare event in the pediatric population was not an uncommon condition and responsible for more than one third of all pediatric and adolescent patients presented with adnexal masses and abdominal pain. Pain assessment in children and adolescents is important to distinguish characteristics of those with torsion and those with an alternate diagnosis.Thus, pediatric and adolescent patients particularly with a pelvic mass size greater than 5 cm, acute onset pain, persistent or recurrent pain have a benign cause and not missing the devastating condition that needs emergent attention. Thus, a strategy of earlier and liberal use of Diagnostic Laparoscopy (DL) may improve ovarian salvage.

Increased tibial tuberosity torsion has the greatest predictive value in patients with patellofemoral instability compared to other commonly assessed parameters.

PURPOSE: The multifactorial nature of patellofemoral instability requires a comprehensive assessment of the affected patients. While an association between tibial tuberosity (TT) torsion and patellofemoral instability is known, its specific effect has not yet been investigated. This study investigated the effect of TT torsion on patellofemoral instability. METHODS: This retrospective cohort study compared patients who underwent surgical intervention for patellofemoral instability and asymptomatic controls. TT torsion was measured in addition to other commonly assessed risk factors for patellofemoral instability using standardised computed tomography (CT) data of the lower extremities. The diagnostic performances of the assessed parameters were evaluated using receiver operating characteristic curve analysis and odds ratios (ORs) were calculated. RESULTS: The patellofemoral instability group consisted of 79 knees, compared to 72 knees in the asymptomatic control group. Both groups differed significantly in all assessed parameters (p < 0.001), except for tibial torsion (n.s.). Among all parameters, TT torsion presented the best diagnostic performance for predicting patellar instability with an area under the curve of 0.95 (95% confidence interval [CI], 0.91-0.98; p < 0.001). A cut-off value of 17.7° yielded a 0.87 sensitivity and 0.89 specificity to predict patellar instability (OR, 55.2; 95% CI, 20.5-148.6; p < 0.001). CONCLUSION: Among the evaluated risk factors, TT torsion had the highest predictive value for patellofemoral instability. Patients with TT torsions ≥ 17.7° showed a 55-fold increased probability of patellofemoral instability. Therefore, TT torsion should be included in the assessment of patients with patellofemoral instability. LEVEL OF EVIDENCE: Level III.

Fundus torsion following inferior oblique muscle weakening.

PURPOSE: To determine the postoperative fundus torsion following surgical inferior oblique (IO) weakening in patients with inferior oblique overaction (IOOA). METHODS: In this interventional case series, 37 patients with IOOA ≥ +1 and reliable preoperative fundus photographs were included. IO weakening was accomplished through myectomy or anterior transposition. Fundus photography was repeated at 3 months' follow-up. The primary outcome was change of disk foveal angle (DFA), measured as the angle between the line connecting the center of the fovea and optic disk and horizontal. Success or normal fundus torsion was defined as a postoperative angle of 0° to 8° of extorsion. Residual extorsion was defined as postoperative extorsion of > 8°. Postoperative intorsion was defined as any amount of induced intorsion. RESULTS: Mean age of patients (56% females) was 6.46 ± 6.79 years. At follow-up at least 3 months after surgery, the mean change of DFA was 7.79 ± 6.24° of reduction of extorsion after IO myectomy (P < 0.001) and 6.05 ± 6.07° after IO anterior transposition (P = 0.005). Normal fundus torsion was achieved in 50% of patients after myectomy and 36.4% of patients after anterior transposition. Residual extorsion was observed in 49% of patients; induced intorsion in 5%. CONCLUSIONS: Using objective measurement of fundus photographs, fundus extorsion was decreased in 94.7% of patients after myectomy or anterior transposition.

Use of Indocyanine Green to Evaluate Ovarian Perfusion After Laparoscopic Detorsion. A Step-By-Step Demonstration Video.

OBJECTIVE: Demonstrate the usefulness of using indocyanine green after laparoscopic ovarian detorsion to save the ovary. DESIGN: A step-by-step video demonstration of a surgical technique. SETTING: Ovarian torsion is one of the most common gynecological emergencies, mainly affecting patients younger than 20 years of age [1], and causes 2% to 7% of acute abdomens [2]. It is not advisable to routinely perform ovariectomy even with a necrotic ovary appearance [1]. Furthermore only in a small percentage of cases (16%) necrosis has been confirmed histologically [2]. Some studies have demonstrated that using indocyanine green to evaluate ovarian perfusion is inexpensive, low risk, and easily reproducible [3-5]. INTERVENTIONS: A 17-year-old patient was referred to our hospital for acute abdominal pain. Ultrasound revealed ovarian torsion; therefore, the patient underwent surgical treatment. During laparoscopy, the presence of a right ovarian torsion was confirmed. A lesion compatible with a hemorrhagic corpus luteum of 6 cm was present on the ovary affected. Before ovarian detorsion, indocyanine green was administered intravenously at a 0.5 mg/kg dose. The first aspect noted was the total lack of ovarian vascularization; then ovarian detorsion was performed. At this point, using technology of Rubina (KARL STORZ SE & Co. KG, Tuttlingen, Germany), it was possible to highlight the progressive ovarian revascularization. Ovarian reperfusion occurred starting from the ovarian hilum and ending at the periphery. We proceeded with enucleation of the hemorrhagic corpus luteum by stripping technique, with subsequent ovarian reconstruction with continuous 2-0 monofilament suture. Finally, we fixed the ovary to the stump of the right round ligament. The final view highlights good ovarian vascularization. No complications occurred; the patient was discharged on the first postoperative day. A 6-month follow-up ultrasound confirmed the recovery of the vascularization of ovary. CONCLUSION: Using indocyanine green represents a valid option to evaluate ovarian perfusion after detorsion. It could help the surgeon decide to save the ovary and thus allow fertility-sparing surgery in more cases.

Ovarian Torsion and Oophorectomy in Childhood: A Case Report.

BACKGROUND: Ovarian torsion in infants can be asymptomatic or may present with abdominal mass and malnutrition. It is an uncommon and non-specific condition in children. We report a girl who underwent detorsion and ovariopexy for suspected ovarian torsion after a previous oophorectomy. The role of progesterone therapy is determined in reducing the size of adnexal mass. CASE PRESENTATION: The patient was diagnosed with right ovarian torsion and underwent an oophorectomy at one year of age. About 18 months later, she was diagnosed with left ovarian torsion and underwent detorsion with lateral pelvic fixation. Despite the pelvic fixation of the ovary, a continuous increase in the volume of the ovarian tissue was evident during successive ultrasounds. Progesterone therapy was started at five years of age in order to prevent retorsion and preserve the ovarian tissue. In successive follow-ups during the therapy, ovarian volume decreased, and its size (27*18 mm) was restored. CONCLUSION: The presented case reminds doctors of the possibility of ovarian torsion in young girls with pelvic pain. More research is needed on the use of hormonal drugs, such as progesterone, in similar cases.

Left medial liver lobe torsion and postoperative acute gastric rupture in a 2.5-year-old male-castrated Flemish Giant rabbit (Oryctolagus cuniculus).

A 2.5-year-old male-castrated rabbit presented with acute abdominal pain, lethargy, and anorexia. Digital radiography revealed increased left-sided hepatomegaly, gastric dilation, and decreased peritoneal serosal detail. Abdominal ultrasonography identified a torsed left liver lobe, gastric dilation, and peritoneal effusion. Surgery confirmed a left medial liver lobe torsion, with subsequent lobectomy and seven days of hospitalization. The patient re-presented 2 days after discharge and suddenly died while hospitalized, with acute gastric rupture, fulminant peritonitis, and multifocal hepatic infarcts diagnosed on necropsy. We believe this is the first recorded imaging diagnosis of a left medial liver lobe torsion in a rabbit.

Contemporary Trends in Laparoscopy and Ovarian Sparing Surgery for Ovarian Torsion in the Pediatric Population.

PURPOSE: Although total oophorectomy (TO) was historically performed in cases of nonviable-appearing ovaries, considerable evidence has demonstrated equivalent outcomes after ovarian sparing surgery (OSS) as well as long-term fertility preservation benefits. This study sought to compare outcomes of OSS and TO for patients with ovarian torsion. METHODS: Females <21 years old admitted for ovarian torsion were identified from the Nationwide Readmissions Database (2016-2018) and stratified by OSS or TO. Propensity score-matched analysis (PSMA) utilizing >50 covariates (demographics, medical comorbidities, ovarian diagnoses, etc.) was constructed between those receiving TO and OSS. RESULTS: There were 3,161 females (median 15 [12-18] years) with ovarian torsion, and concomitant pathologies included cysts (42%), benign masses (25%), and malignant masses (<1%). Open approaches were more common (52% vs. 48% laparoscopic), and ovarian resection (OSS or TO) was performed in 87% (39% OSS and 48% TO). OSS was more commonly performed with laparoscopic detorsions (60% vs. 40% TO), while TO was more frequent in open operations (59% vs. 41% TO; both p < 0.001). No differences in overall readmissions (7% OSS vs. 8% TO) or readmissions for recurrent torsion (<1% overall) and ovarian masses (<1%) were observed (both groups <1%; p = 0.612). After PSMA, laparoscopy was still utilized less frequently with TO (39% vs. 53%; p < 0.001) despite similar rates of malignant masses. CONCLUSIONS: Overall, these data offer additional support for the current practice guidelines that give preference to OSS as the primary method of treatment for pediatric ovarian torsion in the majority of cases. LEVEL OF EVIDENCE: III. TYPE OF STUDY: Retrospective Comparative Study.

Application of a Composite Score to Predict Adnexal Torsion in Premenarchal and Menarchal Children and Adolescents.

STUDY OBJECTIVE: The study objective was to apply a previously created composite score for the prediction of adnexal torsion in children and adolescents to a larger group of heterogeneous patients to test its validity and to refine this scoring system to more accurately predict adnexal torsion. METHODS: This was a retrospective chart review at a tertiary care children's hospital and its affiliates. Participants were female patients 0-20 years of age who underwent surgery for suspected adnexal torsion from 2016 to 2019. Data were collected from outpatient, emergency department, and inpatient notes, radiographic data, and operative reports. The primary outcome was the accuracy and predictive value of the total composite score (TCS) to identify or exclude adnexal torsion. RESULTS: Of the 291 patients with suspected adnexal torsion who went to the operating room during the study period, 168 (57.8 %) had confirmed adnexal torsion. The accuracy of the TCS, which included presence of vomiting, adnexal volume, and adnexal ratio, in predicting or excluding torsion was 83.6 % for all patients, 92.1 % for premenarchal patients, and 81.3 % for menarchal patients. A variation of the TCS that included only vomiting and adnexal volume had an accuracy of 85.8 %. CONCLUSIONS: Our study demonstrates the accuracy and reproducibility of a previously published composite score to predict adnexal torsion in children and adolescents. It also further refines this score to a potentially more clinically useful tool. Future studies are needed to prospectively evaluate these composite scores and their implementation in clinical settings. LEVEL OF EVIDENCE: III.

Lung lobe torsion associated with chest wall defects in a dog.

An 8-year-old, spayed, female poodle presented with exercise intolerance, lethargy, respiratory distress, retching, hyporexia and diarrhoea. Thoracic radiographs revealed increased opacity in the left cranial thoracic region. The fifth and sixth ribs appeared to be bulging cranially to caudally, and CT and surgical exploration confirmed the presence of a thoracic wall defect in that area. CT showed abrupt occlusion of the bronchus that branches into the left cranial lobe and consolidation of the caudal segment of left cranial lung lobe, which led to the diagnosis of lung lobe torsion. A thoracotomy was performed, the twisted lung lobe was surgically excised, and the defect in the thoracic wall was repaired. Respiratory distress gradually improved after the surgery, and there were no identified complications within the 2-year period following the procedure. Based on our literature search, this is the first reported case of lung lobe torsion caused by a thoracic wall defect in a dog.

Ovarian torsion masquerading as a ureteral stone.

BACKGROUND: Abdominal pain is the most common complaint within the emergency department (ED) and has many varied etiologies. Some of these conditions can be medical emergencies, including ovarian torsion. While representing just 3% of gynecologic emergencies, ovarian torsion should be considered in all females presenting to the ED with abdominal or pelvic complaints. CASE: A 38-year-old G5P5 female with a past medical history significant for ureterolithiasis presented to a freestanding ED with abdominal pain, nausea, and vomiting. She developed sudden onset of right sided abdominal pain radiating to her right flank upon awakening. The initial differential diagnosis was for ureterolithiasis or appendicitis. Her complete blood count (CBC) was normal, and testing for pregnancy, infection, and hematuria was negative. Computed topography (CT) imaging of the abdomen and pelvis revealed a 9 cm adnexal mass, consistent with a possible dermoid cyst. A pelvic ultrasound was ordered which showed a possible ovarian torsion. She was transferred to a tertiary care hospital where she had a laparoscopy with right-sided oophorectomy and salpingectomy performed. DISCUSSION: This patient presented with abdominal pain, nausea, and vomiting and was first suspected to have ureterolithiasis or appendicitis. She was found to have an ovarian torsion with a dermoid cyst, which resulted in the loss of her ovary and fallopian tube. This case demonstrates the importance of including gynecologic emergencies in the differential on all female patients presenting with abdominal pain.

[Postoperative pulmonary torsion after upper lobectomy by thoracotomy]. / L'image du mois. Torsion pulmonaire en post-opératoire après lobectomie supérieure par thoracotomie.

The aim of this case report is to describe a lobar torsion after elective pulmonary resection. This is a rare but potentially fatal condition in which the lung rotates on its own axis. Although this condition may occur spontaneously, it most often follows lobectomy. Early diagnosis and prompt surgical intervention are essential to prevent complications. Treatment is surgical, and involves repositioning the lung in a physiological position. However, the presence of ischaemic lesions may lead to the resection of the lung portion concerned.

Le but de cet article est de décrire le cas d'une torsion pulmonaire survenue après une résection pulmonaire élective. C'est une affection rare, mais potentiellement mortelle, qui se traduit par une rotation du poumon sur son propre axe. Bien que cette affection puisse survenir de manière spontanée, elle apparaît le plus souvent dans les suites d'une lobectomie. Un diagnostic précoce et une intervention chirurgicale rapides sont essentiels afin de prévenir les complications. Le traitement est chirurgical et consiste à repositionner le poumon en position physiologique. Toutefois, la présence de lésions ischémiques peut conduire à une résection plus large de la portion pulmonaire concernée.

Synchronous bilateral ovarian torsion followed by recurrent unilateral torsion in a patient undergoing fertility treatment: A case report and literature review.

BACKGROUND: Ovarian torsion (OT) is a gynaecological emergency and requires prompt recognition and treatment in order to prevent the loss of ovarian function. Patients who are undergoing fertility treatment are at an increased risk of developing OT. OBJECTIVE: The diagnosis of OT in patients undergoing fertility treatment can be challenging as they often present with abdominal pain and other non-specific symptoms. We highlight the importance of early diagnosis of suspected torsion and performed a literature review on cases of bilateral OT to review its presentation, investigation, and subsequent management. CASE REPORT: A 32-year-old nulliparous woman who was undergoing controlled ovarian stimulation presented with lower abdominal pain and was initially managed as ovarian hyperstimulation syndrome (OHSS). Her pain did not subside following conservative management and she proceeded to have a laparoscopy which demonstrated synchronous bilateral ovarian torsion (SBOT), both ovaries were detorted. Eight months later, she was preparing for her frozen embryo transfer (FET) cycle, patient again presented with significant right sided abdominal pain and was found to have a recurrent torsion of the right ovary which was again detorted successfully. CONCLUSIONS: Clinicians should have a low-threshold to investigate and rule out OT in patients who present with lower abdominal pain, especially in those with additional risk factors for torsion. Patients with confirmed torsion can be successfully managed with detorsion of the ovaries. Further research is needed to determine the best management option for patients with recurrent torsion episodes.

Fertility preserving management of ovarian torsion.

OBJECTIVE: To analyze characteristics of acute and chronic ovarian torsion, review treatment recommendations, and present possible surgical techniques for fertility preservation in young women. DESIGN: Literature review and demonstration of perioperative management of ovarian torsion using radiologic images and intraoperative video footage. Ovarian torsion is mostly mentioned in context of gynecologic emergencies, where acute ovarian torsion with arterial obstruction leads to ovarian ischemia and necrosis. However, ovarian torsion can also occur as a partial or intermittent torsion with venous and lymphatic obstruction, followed by ovarian swelling. In both cases, surgical management of ovarian torsion commonly includes oophorectomy, although leading guidelines recommend preservation of the ovary. We here aimed to raise awareness for the clinical features of ovarian torsion and demonstrate adequate perioperative management, thereby avoiding surgical overtreatment in young women. SETTING: Medical University of Vienna, Department of Obstetrics and Gynecology. PATIENT(S): We present a case of acute ovarian torsion with a consequently ischemic ovary as well as a case of chronic ovarian torsion with related massive ovarian edema. The patients included in this video gave consent for publication of the video and posting of the video online, including social media, the journal website, scientific literature websites (such as PubMed, ScienceDirect, Scopus, etc.), and other applicable sites. INTERVENTION(S): Laparoscopic management with detorsion of the torquated ovaries, cystectomy on an ischemic ovary and oophoropexy to the pelvic side wall and utero-ovarian ligament to prevent recurrence. MAIN OUTCOME MEASURES: Postoperative relief of pain and normalization of ovarian size and morphology on ultrasound imaging. RESULTS: The current cases show successful conservative surgical management of ovarian torsion, hence preserving hormonal function and fertility in young women. CONCLUSION: Although it is recommended to preserve fertility in young women affected by ovarian torsion, surgical overtreatment by means of oophorectomy is still common in clinical routine. Increasing awareness for the clinical characteristics of acute and chronic ovarian torsion, as well as for the importance of preservation of the ovary, is crucial. We therefore believe that ovarian torsion and its surgical management deserve increased attention in the future.

[A pregnant patient with acute abdominal pain]. / Een zwangere met acute buikpijn.

A 33-year-old 20 weeks pregnant woman with severe abdominal pain in the past 1,5 hour visits the emergency department. MRI suggested an appendicitis. Laparoscopy showed an adnexal torsion. The right ovary was twisted back, and a good revascularization was observed shortly after. Patient was discharged one day post-surgery and had an uneventful pregnancy.

Combined Utero-Ovarian and Round Ligament Oophoropexy for Recurrent Torsion of Normal Adnexa: A Case Series.

STUDY OBJECTIVE: Recurrent torsion of otherwise normal adnexa (not involving adnexal cysts) has been reported in young girls and adolescents. Previous ovarian fixation techniques (oophoropexy), such as plication of the utero-ovarian ligament, appear to have limited efficacy in preventing recurrent torsion. A novel technique combining plication of the utero-ovarian ligament and suturing of the ovary to the round ligament has recently been described. In this study, we describe our short-term experience with the combined utero-ovarian and round ligament oophoropexy technique. METHODS: Patients who underwent combined oophoropexy as a primary fixation technique or as a secondary fixation technique (ie, after failure of a previous fixation) due to recurrent torsion of otherwise normal adnexa between January 2020 and December 2022 were included in this retrospective cohort study. Follow-up to assess for further torsion events was conducted by telephone interview. RESULTS: Ten patients underwent combined utero-ovarian and round ligament oophoropexy during the study period. In all cases, at least 2 episodes of torsion of otherwise normal adnexa were surgically diagnosed before oophoropexy (range 2-4). The median patient age at the time of combined oophoropexy was 21.8 years (range 9.1-35.7 years); 3 were premenarchal, and 7 were postmenarchal. After a median follow-up of 19.1 months (range 3.0-29.3 months), only 1 case of recurrent torsion occurred. CONCLUSION: Combined utero-ovarian and round ligament oophoropexy is novel oophoropexy procedure that may reduce the risk of recurrent torsion. However, longer follow-up is needed to determine its efficacy.

Torsion of uterus in twin pregnancy.

Uterine torsion is defined as a rotation of uterus around its axis by more than 45° in its longitudinal length. Uterine torsion is very rare, it is reported that a physician encounters it only 1 time in a lifetime. Our case describes uterine torsion in a twin pregnancy, in a completely asymptomatic patient, where the dia-gnosis was made only peroperatively.

Isolated Fallopian Torsion: A Pediatric Case Series.

Isolated fallopian tube torsion is a rare cause of acute abdominal pain in adolescent females. It is known to be a surgical emergency as it may lead to ischemia of the fallopian tube which can result in necrosis, infertility or infection. Presenting symptoms and radiographic findings are vague making diagnosis difficult, often requiring direct visualization in the operating room to make the definitive diagnosis. There has been an increase in this diagnosis at our institution in the previous year prompting compilation of cases and a literature review.

Changing Practices in the Surgical Management of Adnexal Torsion: An Analysis of the National Surgical Quality Improvement Program Database.

OBJECTIVE: To evaluate trends in the surgical management of adnexal torsion and to evaluate these trends with respect to the updated American College of Obstetricians and Gynecologists (ACOG) guidelines. METHODS: We performed a retrospective cohort study using the National Surgical Quality Improvement Program database. Women who underwent surgery for adnexal torsion between 2008 and 2020 were identified on the basis of International Classification of Diseases codes. Surgeries were grouped as either ovarian conservation or oophorectomy with the use of Current Procedural Terminology codes. Patients were also grouped into year cohorts with respect to the publication of the updated ACOG guidelines (2008-2016 compared with 2017-2020). Multivariable logistic regression, weighted by cases per year, was used to assess differences between groups. RESULTS: Of the 1,791 surgeries performed for adnexal torsion, 542 (30.3%) involved ovarian conservation and 1,249 (69.7%) involved oophorectomy. Older age, higher body mass index, higher American Society of Anesthesiologists classification, anemia, and diagnosis of hypertension were significantly associated with oophorectomy. There was no significant difference in the proportion of oophorectomies performed before 2017 compared with after 2017 (71.9% vs 69.1%, odds ratio [OR] 0.89, 95% CI 0.69-1.16; adjusted OR 0.94, 95% CI 0.71-1.25). A significant decrease in proportion of oophorectomies performed each year was identified over the entire study period (-1.6%/y, P =.02, 95% CI -3.0% to -0.22%); however, the rates did not differ before and after 2017 (interaction P =.16). CONCLUSION: There was a modest decrease in the proportion of oophorectomies for adnexal torsion performed per year over the study period. However, oophorectomy is still commonly performed for adnexal torsion, despite updated guidelines from ACOG recommending ovarian conservation.