Endovenous laser ablation (EVLA): a review of mechanisms, modeling outcomes, and issues for debate.

Endovenous laser ablation (EVLA) is a commonly used and very effective minimally invasive therapy to manage leg varicosities. Yet, and despite a clinical history of 16 years, no international consensus on a best treatment protocol has been reached so far. Evidence presented in this paper supports the opinion that insufficient knowledge of the underlying physics amongst frequent users could explain this shortcoming. In this review, we will examine the possible modes of action of EVLA, hoping that better understanding of EVLA-related physics stimulates critical appraisal of claims made concerning the efficacy of EVLA devices, and may advance identifying a best possible treatment protocol. Finally, physical arguments are presented to debate on long-standing, but often unfounded, clinical opinions and habits. This includes issues such as (1) the importance of laser power versus the lack of clinical relevance of laser energy (Joule) as used in Joule per centimeter vein length, i.e., in linear endovenous energy density (LEED), and Joule per square centimeter vein wall area, (2) the predicted effectiveness of a higher power and faster pullback velocity, (3) the irrelevance of whether laser light is absorbed by hemoglobin or water, and (4) the effectiveness of reducing the vein diameter during EVLA therapy.

Some controversies in endovenous laser ablation of varicose veins addressed by optical-thermal mathematical modeling.

Minimally invasive treatment of varicose veins by endovenous laser ablation (EVLA) becomes more and more popular. However, despite significant research efforts performed during the last years, there is still a lack of agreement regarding EVLA mechanisms and therapeutic strategies. The aim of this article is to address some of these controversies by utilizing optical-thermal mathematical modeling. Our model combines Mordon's light absorption-based optical-thermal model with the thermal consequences of the thin carbonized blood layer on the laser fiber tip that is heated up to temperatures of around 1,000 °C due to the absorption of about 45% of the laser light. Computations were made in MATLAB. Laser wavelengths included were 810, 840, 940, 980, 1,064, 1,320, 1,470, and 1,950 nm. We addressed (a) the effect of direct light absorption by the vein wall on temperature behavior, comparing computations by using normal and zero wall absorption; (b) the prediction of the influence of wavelength on the temperature behavior; (c) the effect of the hot carbonized blood layer surrounding the fiber tip on temperature behavior, comparing wall temperatures from using a hot fiber tip and one kept at room temperature; (d) the effect of blood emptying the vein, simulated by reducing the inside vein diameter from 3 down to 0.8 mm; (e) the contribution of absorbed light energy to the increase in total energy at the inner vein wall in the time period where the highest inner wall temperature was reached; (f) the effect of laser power and pullback velocity on wall temperature of a 2-mm inner diameter vein, at a power/velocity ratio of 30 J/cm at 1,470 nm; (g) a comparison of model outcomes and clinical findings of EVLA procedures at 810 nm, 11 W, and 1.25 mm/s, and 1,470 nm, 6 W, and 1 mm/s, respectively. Interestingly, our model predicts that the dominating mechanism for heating up the vein wall is not direct absorption of the laser light by the vein wall but, rather, heat flow to the vein wall and its subsequent temperature increase from two independent heat sources. The first is the exceedingly hot carbonized layer covering the fiber tip; the second is the hot blood surrounding the fiber tip, heated up by direct absorption of the laser light. Both mechanisms are about equally effective for all laser wavelengths. Therefore, our model concurs the finding of Vuylsteke and Mordon (Ann Vasc Surg 26:424-433, 2012) of more circumferential vein wall injury in veins (nearly) devoid of blood, but it does not support their proposed explanation of direct light absorption by the vein wall. Furthermore, EVLA appears to be a more efficient therapy by the combination of higher laser power and faster pullback velocity than by the inverse combination. Our findings suggest that 1,470 nm achieves the highest EVLA efficacy compared to the shorter wavelengths at all vein diameters considered. However, 1,950 nm of EVLA is more efficacious than 1,470 nm albeit only at very small inner vein diameters (smaller than about 1 mm, i.e., veins quite devoid of blood). Our model confirms the efficacy of both clinical procedures at 810 and 1,470 nm. In conclusion, our model simulations suggest that direct light absorption by the vein wall is relatively unimportant, despite being the supposed mechanism of action of EVLA that drove the introduction of new lasers with different wavelengths. Consequently, the presumed advantage of wavelengths targeting water rather than hemoglobin is flawed. Finally, the model predicts that EVLA therapy may be optimized by using 1,470 nm of laser light, emptying of the vein before treatment, and combining a higher laser power with a greater fiber tip pullback velocity.

Child Abuse, Misdiagnosed by an Expertise Center: Part I-Medico-Social Aspects.

Child abuse is a dangerous situation for an infant. Professionals need to weigh the risk of failing to act when children are seriously harmed against the serious harm done by carrying out safeguarding interventions. In severe cases, foster care might be advisable. The negative effects for the child's psychosocial development requires that such placement must be based on very solid evidence. Our aim is to identify why Dutch parents whose child may have a medical condition that could mimic symptoms of child abuse have a significant chance of being erroneously convicted and losing custody of their child. As a method, we describe and analyze the following case. An Armenian-Dutch newborn (uncomplicated term vaginal delivery), starting at two weeks after birth, developed small bruises on varying body locations. At two months, a Well-Baby Clinic physician referred the girl to a university hospital, mentioning that there were no reasons to suspect child abuse and that her Armenian grandmother easily bruised as well. However, before consultation by a pediatrician of the hospital-located Expertise Center for Child Abuse, the parents were suspected of child abuse. Based on the expertise center's protocols, skeletal X-rays were made, which showed three healed, asymptomatic rib fractures, while invalid statistics suggested, incorrectly, a 10-100 times more likely non-accidental than accidental cause of the symptoms (discussed in Part II of this series). The expertise enter physician ignored any argument that could show parental innocence, including the positive parent-child relationship reported by the Well-Baby Clinic and the general practitioner. The girl and her older brother were placed in a family foster home and then in a secret home. The case radically resolved when a large bruise also developed there, and an independent tissue disease specialist diagnosed a hereditary connective tissue disorder in the mother, implying that the girl's bruises and rib fractures could well be disease-related. In conclusion, if child abuse is suspected, and foster care placement considered, the patient and the parents should be thoroughly investigated by an independent experienced pediatrician together with an experienced pediatric clinical psychologist or psychotherapist to produce an independent opinion. Children deserve this extra safeguard before being separated from their parents.

Does orthodontic loading influence bone mineral density around titanium miniplates? An experimental study in dogs.

OBJECTIVES: To evaluate whether orthodontic loading has an effect on miniplate stability and bone mineral density (BMD) around the screws supporting those miniplates. SETTING AND SAMPLE POPULATION: Two miniplates were inserted in each jaw quadrant of 10 dogs. MATERIAL AND METHODS: Two weeks later, coil springs were placed between the miniplates of one upper quadrant and between those of the contralateral lower quadrant. The other miniplates remained non-loaded. The dogs were sacrificed 7 or 29 weeks after surgery, and the jaws were scanned with peripheral Quantitative Computed Tomography (pQCT) to assess BMD. RESULTS: The success rate was not significantly different for the loaded and the non-loaded miniplates, but was significantly higher for the maxillary compared to the mandibular ones. Mobility, associated with local inflammation, most often occurred during the transition between primary and secondary stability. pQCT showed higher BMD around mandibular vs. maxillary screws, without significant difference between loaded and non-loaded ones. Furthermore, load direction did not lead to any significant difference in BMD. CONCLUSION: Miniplate stability and BMD of the adjacent bone did not appear to depend significantly on orthodontic loading, but rather on the receptor site anatomy.

Limitations of Dutch Growth Research Foundation Commercial Software Weight Velocity for Age Standard Deviation Score.

BACKGROUND The commercial software for hospitals, Weight Velocity for Age Standard Deviation Score (SDSWVA), claims to document the growth and development of children, although published details are unavailable. The statistics-derived parameter SDSWVA includes the weight velocity at age t, WV(t) (weight gained between t and (t-1.23) years, divided by 1.23), and 3 standard weight velocity curves at average age AA, defined as AA=t-1.23/2 years. SDSWVA denotes the number of standard deviations that WV(t) deviates from the 0 SD weight velocity at AA. WV(t) yielded erroneous outcomes when applied to weights of a seriously underweight boy with an allergy to cows' milk who showed strong weight growth after being fed on food free of cows' milk. The SDSWVA software tacitly suggests that it is more accurate than WV(t). CASE REPORT The case of this boy was previously described in this Journal. Using SDSWVA(t,AA) software, his weight growth was analyzed by his third pediatrician, beginning at age 1.5 years. The diagnosis of the mother with Pediatric Condition Falsification was confirmed, adding 6 months to foster care, which totalled 8.5 months. Testing of the SDSWVA software on the boy's weight curve yielded results that were complex, nontransparent, and as erroneous as WV(t), explaining the misdiagnosis by the third pediatrician. CONCLUSIONS SDSWVA software should not be used for children under 3 years and during variable weight behavior. Erroneous performance, unpublished details, and an error identified in their new but untested software make the Dutch Growth Research Foundation unlikely to meet the 2020 European Union regulations for in vitro medical devices.

Weight velocity equations with 14-448 days time separated weights should not be used for infants under 3 years of age.

Abnormal growth of infants may indicate disease of the children, thus methods to identify growth disorders are wanted in medicine. We previously showed that two-time-points weight growth velocities at age t, calculated by a commercial software product as [Weight(t) - Weight(t - X)]/X, with X = 448 days, were erroneous due to the long separation of 448 days. We were convinced that shorter X-values would solve this accuracy problem. However, our hypothesis is that: "shorter time separations than 448 days cause a decreased accuracy of numerical weight velocity equations in realistic infant weights until an age of about three years". Supporting evidence comes from analyzing how shorter X-values will affect the accuracy of two-time-points weight velocity calculations. We systematically varied X between 1 and 448 days of various P50/0SD-related standard weight curves: (a) P50/0SD with the weights separated by 1 day and X = 1,28,224,448 days; (b) P50/0SD with the weights at variable ages and X = 14-448 days; and (c) case (b) and incorporating weight fluctuations typically occurring in infants. Cases (b) and (c) include details observed in a clinical case. Our results show that the combination of weight fluctuations and varying time intervals between consecutive weights make weight velocity predictions worse for shorter X values in children younger than three years. Because these two causes of failure occur naturally in infants whose weight is regularly measured, other weight velocity equations face the same causes for inaccuracy. In conclusion, our hypothesis suggests that any software that predicts weight velocities should be abandoned in infants < 3 years. Practically, it should require that when (commercial) software weight velocity prediction suggests a medical problem, careful clinical checking should be mandatory, e.g. by linking predicted and exact weight velocities at age t (the latter from the mathematical first derivative at age t of standard weight curves).

Limitations of Weight Velocity Analysis by Commercial Computer Program Growth Analyser Viewer Edition.

Commercial software package "Growth Analyser Viewer Edition" ("GAVE") aims to document, monitor and analyze growth and development in children and adolescents. Although its clinical and scientific use is widespread, there are no published studies that describe the method and its validation. We were informed that GAVE calculates the weight velocity (kg/year) at age t from the weight difference between t and 448 days earlier or at birth, divided by the time difference. We recently discussed a case of false child abuse diagnosis (Pediatric Condition Falsification), resulting in the separation of the child from its parents, in which GAVE played a negative contributing role. To prevent such inappropriate diagnoses, we analyzed GAVE from a schematic representation of the measured clinical weight curve, with precisely defined weight velocities. In conclusion, the 448 days included for weight velocity predictions by GAVE caused the erroneous outcomes. Until the necessary changes to the software are implemented and validated, we advise against the use of GAVE in infants younger than 1.5 years, if multiple weight changes occur within 448 days, and following a long-lasting weight velocity change. Our analysis suggests to discard all medical software packages that lack public description and proof of validation.

The impact of individualized evidence-based decision support on aneurysm patients' decision making, ideals of autonomy, and quality of life.

BACKGROUND: Patients with an asymptomatic abdominal aneurysm and their surgeon were randomized to receive a general brochure (GB) or an IB presenting survival information and a ranking of the treatment strategies. Before and after receiving the brochure, patients filled out questionnaires on their behavior during the consultation, ideals of patient autonomy, and quality of life. Surgeons answered a short checklist evaluating the consultation. RESULTS: One hundred patients participated, 49 in the intervention, 51 in the control group. The IB group had a better understanding of important issues in the treatment decision, had prepared more questions, and was less satisfied with the duration of the consultation. Their impression that the surgeon perceived them more as a medical problem than a patient with a problem increased. They agreed less with the surgeon's advice and lost some of their belief in "the doctor knows best.'' Beforehand, the IB group had a stronger preference for patient-based decisions, but afterward they displayed more surgeon-based decisions. No effects were seen on patients' quality of life. CONCLUSIONS: Individualized evidence-based information stimulated patients' active involvement but in the context of our study led to less patient-based decisions. Patient-made decisions and patient autonomy should, however, not be equated.

Orthodontic loading of titanium miniplates in dogs: microradiographic and histological evaluation.

OBJECTIVES: The objectives of this animal study were to evaluate if orthodontic loading has an impact on osseointegration of screws supporting miniplates, and to describe the histological components of the bone-screw interface. MATERIALS AND METHODS: Eighty orthodontic miniplates were placed in the jaws of 10 dogs. After 2 weeks, a 125 g force was applied between the miniplates of one upper quadrant of each dog and between those of the controlateral lower quadrant. The others, nonloaded miniplates, were considered as controls. Five dogs were sacrificed 7 weeks after implantation and the remaining five dogs after 29 weeks [Short Term (ST) and Long Term (LT) groups, respectively]. Fluorochromes were injected at implantation and at sacrifice. Jaw quadrants were dissected, embedded, cut into undecalcified transverse sections through the screws and finally submitted to microradiographic analysis to allow assessment of bone-implant contact (BIC) and bone volume/total volume (BV/TV). The sections were observed under UV light and stained in order to examine them under ordinary light. RESULTS: Osseointegration occurred around 90/160 screws and consisted mainly in limited repair and remodelling processes of lamellar bone, without inflammation. Wide variations were observed in BIC and BV/TV, but without any significant difference, neither between the loaded and the nonloaded screws, nor according to the direction of load, whereas they were significantly higher in the LT than in the ST group. Nonosseointegrated screws were surrounded by fibrous tissue. Osteoblastic activity, when present in front of these screws, was not sufficient to achieve stability. CONCLUSIONS: Osseointegration underlying orthodontic anchorage was not affected by loading. BIC increased with time and varied according to implantation site. Particularly the tight-fitting screw insertion appeared crucial in determining the appropriate bone healing response.

Pediatric Condition Falsification Misdiagnosed by Misjudged Weight Growth from the Curve of Measured Weights.

BACKGROUND Pediatric condition falsification (PCF) is a rare form of child abuse in which a caregiver fabricates or induces illness in the child. The diagnosis is difficult and controversial and can easily include false positives. CASE REPORT A boy, 3.18 kg birthweight (P25 curve), lost weight between age 56 to120 days. Cow milk allergy was suspected, feeding was changed to elementary formula, and he started catch-up weight growth while remaining significantly underweight. His pediatrician continuously interpreted his low weight as insufficient growth, despite prescribing 3 times the normal caloric intake, concluded that the mother purposely malnourished her son, diagnosed PCF, and the boy was separated from his family (days 502-755 of age). PCF was confirmed by 2 other pediatricians and 3 child protection physicians and was supported by 4 child protection agencies and 6 judges. However, proper analysis of the weight growth (kg/year) from the weight curve showed a normal weight gain. Beyond 120 days of age, weight gain at home was significantly above normal (during 347-489 days: 6.2 versus 3 kg/year of the P50). He reached P25 again at around 516 days. CONCLUSIONS The question "How could so many physicians misjudge weight gain?" has scientific and sociologic aspects. Scientifically, low weight was wrongly interpreted as insufficient weight growth, requiring that physicians learn how to assess weight gain from weight curves. Sociologically, physicians seem to follow a diagnosis made by a colleague without proper evaluation. Arguments provided by the parents against this diagnosis seemed to be neglected. Confirmation bias occurs when any information against PCF is disregarded.

A brain symmetry index (BSI) for online EEG monitoring in carotid endarterectomy.

INTRODUCTION: Carotid endarterectomy is a common procedure as a secondary prevention of stroke, and one of the early controversies in carotid surgery is centered around whether a shunt should be used during this procedure. Although various EEG parameters have been proposed to determine if the brain is at risk during carotid artery clamping, the common procedure is still the visual assessment of the EEG. We propose a brain symmetry index (BSI), that has been implemented as an on-line quantitative EEG parameter, as an additional criterion for shunt need in carotid endarterectomy. METHODS: The BSI captures a particular asymmetry in spectral power between the two cerebral hemispheres, and is normalized between 0 (perfect symmetry) and 1 (maximal asymmetry). The index was evaluated retrospectively in a group of 57 operations in which the EEG and the transcranial Doppler were used as criteria for shunt insertion. In addition, after online implementation of the algorithm, several patients have been evaluated prospectively. RESULTS: If no visual EEG changes were detected, it was found that the change in BSI from baseline, DeltaBSIor=0.06. In this group, one patient suffered from intraoperative stroke and one patient died, most likely from a hyperperfusion syndrome. CONCLUSIONS: The BSI may assist in the visual EEG analysis during carotid endarterectomy and provides a quantitative measure for electroencephalographic asymmetry due to cerebral hypo-perfusion. In patients with a change in the BSI (DeltaBSI) smaller than 0.03 during test clamping, visual EEG analysis showed no changes, whereas if visual EEG analysis did warrant shunting, it was found that DeltaBSI>or=0.06.

Periprocedural prophylactic antithrombotic strategies in interventional radiology: current practice in the Netherlands and comparison with the United kingdom.

PURPOSE: The use of prophylactic antithrombotic drugs to prevent arterial thrombosis during the periprocedural period during (percutaneous) peripheral arterial interventions (PAIs) is still a matter of dispute, and clear evidence-based guidelines are lacking. To create those guidelines, a study group was formed in the Netherlands in cooperation with the Dutch Society of Vascular Surgery and the Society of Interventional Radiology. The study group is called "Consensus on Arterial PeriProcedural Anticoagulation (CAPPA)." MATERIALS AND METHODS: The CAPPA study group devised and distributed a comprehensive questionnaire amongst Dutch interventional radiologists (IRs). RESULTS: One hundred forty-two IRs responded (68 %) to the questionnaire. Almost no IR stopped acetyl salicylic acid before interventions, and 40 % stopped clopidogrel before PAI but not before carotid artery stenting (CAS). A flushing solution on the sideport of the sheath was used routinely by 30 % of IRs in PAI and by 50 % of IRs during CAS. A minority of IRs used a heparinised flushing solution (28 %). Unfractionated heparin was used by 95 % of IRs as bolus; 5000 IU was the most used dosage. Timing of administration varied widely. A majority of IRs (75 %) repeated heparin administration after 1 h. CONCLUSION: A substantial variety exists amongst IRs in the Netherlands regarding the use of prophylactic periprocedural antithrombotic drugs to prevent arterial thrombosis during PAI. When compared with varying results regarding the use of heparin in the United Kingdom, the variety in the Netherlands showed a different pattern. The proven variety in these countries, and also between these countries, emphasises the need for authoritative studies to develop evidence-based practical guidelines.

[Aneurysms of the popliteal vein; treat early]. / Aneurysmata van de V. poplitea: tijdig behandelen.

BACKGROUND: Venous aneurysms are uncommon and of little clinical significance. However aneurysms of the popliteal vein may be a source of potentially lethal recurrent pulmonary emboli and deep venous thrombosis. This is also possible in asymptomatic aneurysms without thrombus. CASE DESCRIPTION: A 67-year-old hairdresser saw a vascular surgeon with a swelling in the left popliteal space that was mildly painful. Further investigations revealed an aneurysm of the popliteal vein without accompanying thrombus. She underwent surgery to remove the aneurysm and maintain the patency of the popliteal vein. Postoperatively the patient was treated with oral anticoagulation therapy for 6 months. Postoperative duplex tests showed the popliteal vein to be patent and without thrombus. The patient continued to have minor oedema after a day of standing at work. CONCLUSION: Aneurysms of the popliteal vein are rare and are often accidental findings during duplex examination for varicose veins. They can also present as recurrent pulmonary embolisms or deep venous thrombosis. Vascular surgery is the treatment of choice due to the risk of thrombo-embolic complications of the aneurysm, also in asymptomatic patients.