Non-Invasive Lamellar Body Count as a Predictor of Fetal Lung Maturity- A Historical Cohort Study

Introduction

Preterm delivery is defined as a birth that occurs before 37 completed weeks or 259 days of gestation. It is associated with about a third of infant mortality in the Western world. As the gestational age drops, the infant is more susceptible to premature morbidity, hypothermia, respiratory distress syndrome (RDS), cerebral hemorrhage and necrotizing enterocolitis (NEC) among other problems. The prominent and leading cause for premature mortality is RDS. RDS is characterized by respiratory failure requiring artificial respiration, in conjunction with characteristic signs on a chest radiograph [1]. It is known that the reason for this condition is the immaturity of pneumocytes and lack of surfactant, which decreases the surface tension of pulmonary alveoli (normal surface tension of the alveoli would allow for better pulmonary compliance). In other words, for the fetus to be able to breathe independently and efficiently, the pulmonary alveoli cells must be mature enough to create surfactant [2]. The necessity of evaluating the degree of lung maturity of the fetus before birth is debated. Some argue against evaluating prenatal lung maturity because it is not the only important system, and because physicians should strive to prolong the pregnancy as close as possible to the estimated delivery date regardless of this evaluation. Proponents of prenatal evaluation of FLM argue that an immature respiratory system is associated with significant morbidity and mortality. Assessing maturity is increasingly more important in cases of preterm premature rupture of the membranes (PPROM) where the decision is between delivering a very preterm infant or extending the pregnancy and risking infection.

There are several common methods for assessing fetal lung maturity. Lecithin sphingomyelin ratio (L/S ratio), is the oldest method. It is an invasive test (requiring amniocentesis) which requires skill and has limited predictive value in situations such as diabetes. Furthermore, the test is performed using expensive and not readily available machinery - Thin layer chromatography - which requires detailed planning and employee training. Results of this test are not available for about 24 hours and inappropriate storage or preparation of the test drastically affects the results. The advantage of this method is that it is probably not influenced by the presence of meconium-stained or bloody amniotic fluid. Another available test is the detection of phosphatidylglycerol (PG), which is also a byproduct of mature lungs and surfactant production. However, PG is present in the amniotic fluid only from week 35. Therefore, this test has very limited utility. Although the presence of PG almost completely excludes the possibility of RDS, its absence is not informative. In addition, like L/S ratio measurement, the PG test results may also vary when taken using a vaginal swab due to bacterial contamination and therefore PG testing requires amniocentesis [3]. This study focused on the Lamellar Body Count (LBC) method which counts lamellar bodies, a by-product of surfactant in the lungs, with a hematologic analyzers used for a standard blood count. Lamellar bodies are the same size and diameter as thrombocytes and therefore, can be counted with equipment found in any hematology laboratory. Thus, this method is affordable and widely accessible, requires no special training, and the results are available within a few minutes. A disadvantage of this method is that samples stained with blood may affect the results.

Lamellar bodies are secretory organelles produced by Type 2 fetal pneumocytes. These organelles contain phospholipids which are major components of surfactant – an essential substance decreasing surface tension on lung alveoli necessary for respiration. In secretion of these organelles surfactant is secreted by exocytosis into the alveolar space, creating a layer of surfactant on the alveoli surfaces. Lamellar bodies appear in the cellular cytoplasm around week 20 of pregnancy, and in amniotic fluid in the following week. A lack of surfactant is known today to be the cause of RDS in neonates. Since surfactant is an essential substance for neonatal respiration, correlation is expected between levels of lamellar bodies in amniotic fluid, the amount of surfactant produced, and fetal lung maturity. Several studies have established the link between the number of lamellar bodies in amniotic fluid and lung maturity of the newborn. Verder et al. examined the lamellar body counts in aspirate from infants born at 30 weeks gestation and found that a cut-off of 8,000 U/μl determined fetal lung maturity with a sensitivity of 75% and specificity of 72% [4]. The study was conducted on 200 infants, at different centers and laboratories, and showed a strong relationship between the number of lamellar bodies and lung maturity. These test results may help the team prepare for the treatment of the newborn and determine whether to administer surfactant (which is not administered to 50% of infants born before week 30 (3)) and prompt treatment with surfactant has been shown to improve the prognosis of the neonate [5].

Walker et al. examined 249 samples of lamellar bodies from women between 37-41 weeks gestation who were delivered by elective cesarean section. Theses samples were taken during surgery. The study found that each additional week of pregnancy increased the LBC, with the highest increase in production during weeks 37-38. This study only examined births that were at term, therefore the variance was not high enough to establish a threshold degree of lung maturity, certainly at the earlier stages of pregnancy, who are characterized by RDS [6]. Joutsi-Korhonen et al. tested the degree of correlation between the L/S ratio and examination of lamellar bodies from amniocentesis using XE-2100 hematological analyzers (Sysmex, Chuo-ku, Japan) and found a good correlation. This work set a threshold value of 35,000 U/μl to determine lung maturity, and 6,000 U/μl to determine immaturity with a large intermediate area of 7000-35000 U/μl. Therefore, it was recommended to use the test as primary screening, and use the thin layer chromatography method for the intermediate values. [7] However, this study considered only samples in cases of IUGR and macrosomia in the setting of possible gestational diabetes, and 6 samples from twin pregnancies. This may have influenced the variance in lamellar body counts and made the identification of a clear threshold for review more difficult. In addition, the study noted that diabetic women had significantly more lamellar bodies than non-diabetic women did, even though one of the known complications of neonates of diabetic mothers is RDS.

This is consistent with other studies on diabetic women [8]. This matter raises the question of whether the RDS mechanism in these infants is not producing enough surfactant, or whether is it somehow deficient qualitatively. it is possible that a higher threshold might be required for these women, but this is beyond the scope of this study. In addition, in the study, 69% of the women were examined at 37-40 weeks of gestation. It is possible that the difference in the number of lamellar bodies during this period is negligible in accordance with the advanced fetal lung maturity. Besnard et AL published a meta analysis comparing the LBC test and the L/S ratio in predicting fetal lung maturity. The study included 13 studies conducted between 1999-2009 in which lung maturity was examined using both methods and produced ROC curves for each. The results showed that testing the lamellar bodies was as least as effective as the L/S ratio and can be used as a test for the majority and not only for initial screening. However, in some of the studies included, it was not specified whether some women had diabetes, whether it was a multiple pregnancy and other factors that could have affected the count and the outcome. Although the aim of this study was to compare standard testing methods and differs from the purpose of the present study, it adds to evidence that the lamellar body test is safe and worthwhile [9].

One study investigated determining lung maturity prematurely and gathering amniotic fluid from the surface of the vagina following PPROM. Salim et al collected vaginal samples of amniotic fluid for testing LBC from 75 women presenting with PPROM who were 27 to 36 weeks pregnant. This study determined that over 28,000 U/μl indicates fetal lung maturity with a specificity of 100% and sensitivity of 75% and that below 8,000 U/μl fetal lungs are not mature, with a sensitivity of 98%. This study includes a large intermediate area, and we believe that there were insufficient samples to reach a more precise threshold [10]. We found only one study that claimed testing LBC using an amniotic fluid sample from the vaginal surface was not effective. This retrospective study from the Netherlands, compared the assessment of lung maturity by amniocentesis and tested the L/S ratio and the lung maturity by checking LBC vaginal swabs after PPROM. The L/S ratio group included 260 maternity patients and the LBC group included 76 women in labor. The study found the LBC testing was inferior to the usual examination and is unsuccessful in predicting RDS. In this study, the ROC curve of the LBC from vaginal samples for predicting RDS appears almost random. However, the study had several weaknesses: first, testing the LBC occurred in different centers by various devices, while it has been clearly shown in previous studies that this leads to varying results and a more stringent threshold is needed for some of these devices [11]. in this study a value of 20,000 U/μl LB was chosen as the threshold for predicting fetal lung maturity, but it was not specified how this value was chosen, and it may be too low.

The issue of the management of birth in the case of PPROM is debated in the literature. Preterm rupture of membranes and conservative management may lead to infection, whereas early, active delivery endangers the neonate with complications related to prematurity. The PPROMT study addressed precisely this dilemma. The study showed that induction of labor in women with PPROM between 34-36 weeks without obstetrical indications, suffered various complications of prematurity, including RDS. It is possible that for these cases, the vaginal surface LBC test will help determine when to schedule the delivery date when the risk of RDS is minimal, before the development of an intrauterine infection endangers the mother and the fetus. Currently, the LBC test is the most promising emerging test for determining fetal lung maturity. It is inexpensive, accessible, sensitive, and several studies have shown that it can predict lung maturity based on samples from vaginal swabs taken following premature rupture of membranes. The aim of this study is to examine if LBC taken from vaginal swab after PPROM, can predict fetal lung maturity (FLM) and the risk of RDS.

Methods

This retrospective cohort study included 307 pregnant women in the second and third trimesters of gestation. vaginal samples of amniotic fluid after PPROM were taken from these women and the LBC was examined, in addition to the 307 babies born to these women. Inclusion criteria for the study population were pregnant women at 28-41 weeks of gestation with PPROM with a singleton pregnancy and no need for immediate delivery, such as chorioamnionitis or fetal distress. Exclusion criteria for the study population were multiple pregnancies, fetuses without a pulse, longer than 14 days between the collection of the sample and delivery, bloody samples (the machine counts platelets as lamellar bodies), and women who arrived at the emergency room with ruptured membranes and immediate indication for delivery- such as chorioamnionitis or fetal distress. Data collected from electronic medical records included maternal demographics (maternal age, gestational diabetes, pre-eclampsia) pregnancy follow-up (fetal sex, intrauterine growth restriction (IUGR), gestational age at delivery, and pregnancy complications at birth i.e pre-eclampsia, gestational diabetes etc.). Delivery data - type (spontaneous vaginal birth, birth by instruments or cesarean), maternal fever during delivery, indication of complications during labor and delivery (nonreassuring monitoring, meconium). Data obtained on newborns included outcomes of RDS according to the accepted clinical definition: respiratory failure of a premature neonate (including the need for mechanical ventilation, surfactant and admission to the neonatal intensive care unit) near delivery, combined with a typical chest x-ray [12] as noted in the medical records. Neonatal data included sex, birth weight, Apgar scores, umbilical artery blood gas values and jaundice.

The Research Variables

The samples were collected using a vaginal swab following rupture of membranes in the delivery room and in the high-risk pregnancy department at Meir Medical Center. The samples were taken and the count was carried out on blood counts analytic device type ADVIA 2120i within a few hours. The information was saved in the BIRTH CARE system and the OFEK system The women’s Data was taken from the BIRTH CARE system (medical acceptance letters, birth report, financial analysis emperors, letters of release) and the data of the neonates were taken from METAVISION and OFEK. The data was collected in tables comparing the index of the lamellar bodies and the presence of RDS in the newborn.

Statistical Methods

To test the hypothesis, comparison was made between the index of the lamellar bodies found in the samples obtained from the women and the outcome of the neonates. In order To examine the differences between the Variables, a t-test for two independent variables was used. To examine differences in distribution between groups, chi-square tests were performed. Finally, to examine the contribution of the independent variable (lamellar bodies) on the dependent variable (neonatal respiratory complications), logistic regression was conducted taking into consideration potential confounders. During Regression analysis stratification by week of pregnancy was made.

Sample Size

In calculating the sample size, we assumed that the incidence of RDS in the neonates (mostly premature babies) in our study will be approximately 20%, consistent with data previously reported in medical literature [13]. According to this assumption, the sample size was based on a proportion confidence interval using the formula:

z for the confidence interval being 1.96, e (acceptable deviation) being 0.05, and the proportion P being 0.2. The sample size obtained was 246 with a anticipation of 50 cases of RDS. Since our ratio was stringent, we expected a higher rate of newborns suffering from RDS. In this scenario, it will be possible to characterize risk factors and prediction variables for those neonates, mainly the LBC.

Results

The study included 307 samples taken from vaginal swabs of women following rupture of membranes. Seventy-eight cases did not meet the study inclusion criteria: 38 cases delivered babies more than two weeks after the sample was taken, 35 cases were multiple pregnancies, two cases were stillbirths and the sample was contaminated in three cases. A total of 229 cases met the inclusion criteria and were included in the study. To examine differences between neonates with and without RDS, chi-square tests, t-tests for independent samples, and Kruskal-Wallace tests for independent samples were used. Maternal clinical and demographic data of the study are presented in Table 1. The age range of the mothers ranged from 17 to 55 years, with an average of 30.9 (SD 5.8) years. Gestational diabetes was present in 11.4% of the mothers and 9.7% had preeclampsia. Neonatal data is presented in Table 2. There were 40.2% females and 59.8% males. Gestational age at birth ranged from 31 to 41 weeks, with an average of 34.3 (SD 1.9) weeks. The distribution of the infants’ weights at birth was as follows- 38.6% weighed 2 to 2.5 kg, 23.3% weighed 2.5 to 4 kg, 15.7% had a weight of 1.75 to 2 kg, 12.9% had a weight of 1.5 -1.75 kg, 5.2% had a weight of 1.25 to 1.5 kg, 3.3% weighed 4 kg and above, while 1% weighed 1 to 1.25 kg. In the LBC a range from 1 to 370 was observed with an average of 40.9 (SD 44.2). in terms of IUGR, 52.7% of fetuses shown growth retardation while 47.3% did not. Most (51.1%) were born by Caesarean section, while the rest (48.9%) were vaginally delivered. In addition, 4.9% were conceived through IVF. 4.8% of the mothers had fever. 55.9% of infants had jaundice and 5.2% of infants suffered from RDS. As shown in Table 1, no significant differences in maternal data were observed in both groups (with and without RDS) in the average age, the rate of maternal fever, preeclampsia, diabetes and in vitro fertilization.

Table 1: Clinical and demographic background of the cohort.

Table 2: Varaiation in averages of the quantative variables in cases with and without RDS.

It was found that neonates with IUGR had statistically significant less incidence of RDS (10%) than neonates that were not IUGR (50.5%) (Χ2 = 9.408, p = .002). As shown in Table 2, a significantly lower LBC (p = 0.005) was found in cases with RDS (18.8 3± 6.5) compared to cases without RDS (40.87 ± 3.59). In addition, cases with RDS were delivered earlier (33.00 ± 0.35 weeks) compared to cases without RDS (34.35 ± 0.15) (p = 0.014). in Table 3 it is shown that there were no significant differences between the newborns with or without RDS in gender or weight. however significantly more newborns with RDS had jaundice (91.7%) when compared with newborns without RDS (53.9%). Analysis of the relationship between gestational age and LBC (Figure 1) had a strong positive correlation (r = 0.308, p = 0.000). meaning when the LBC was conducted at an earlier stage of gestation the LBC was higher as demonstrated in Figure 2. To test whether research metrics (including gestational age at LBC) significantly predicted RDS, logistic regression was conducted (Figure 2) with all the indicators in the study confounders. As mentioned above, since there were no cases of RDS among cases with diabetes, IVF, and IUGR, it was not possible to include these measures in the analysis. The regression results are shown in Table 4. The model correctly classified RDS 93.6% of the time, but did not significantly explain differences in RDS (X2 = 15.251, p = 0.084). Thus, none of the confounding factors significantly predicted chance of RDS. In order to examine the relationship between RDS and LBC, the confidence intervals of LBC were tested for infants with RDS and without RDS. Table 5 shows the mean, standard deviation, and confidence intervals that were found.

Table 3: Neonatal data differences in cases with and without RDS.

Table 4: Logistic regression predicting RDS according to research variables.

Note: *P<0.05, **P<0.01.

Table 5: Confidence intervals of LBC for neonates with/without RDS.

Note: CI, confidence interval.

Figure 1: Birth weight percentages according to RDS.

Figure 2: Lamellar body count (LBC) as a function of gestational age.

Main Findings

We found a direct correlation between the occurrence of RDS and LBC, gestational age at birth, IUGR, and jaundice. That is, cases of RDS were born earlier, had the lower LBC scores, and higher incidence of jaundice and IUGR compared to cases without RDS. It can be said that with a 95% confidence interval, the result of LBC higher than 36.06 indicates pulmonary maturity, while LBC ≤33 indicates a risk of RDS.

Discussion

Primary outcomes

The aim of this study was to determine if LBC from amniotic fluid collected from the vaginal surface after PROM can predict neonatal lung maturity and chances of RDS. The issue of determining fetal lung maturity by LBC has been reported in the literature, however very few reports examined swabs collected from the vaginal surface after PROM. Moreover, in literature and accepted guidelines (ACOG) there are acceptable thresholds for pulmonary maturity (50,000 units) and thresholds for pulmonary immaturity (15000 units) with a large interval remaining that does not aid in medical team decision making. LBC levels obtained in the early weeks of pregnancy and from infants with RDS are significantly lower than those obtained in later weeks of pregnancy and healthy infants. In this study, performed on 307 samples taken from vaginal surfaces at Meir Hospital, a clear correlation was found between the LBC result and the risk of RDS. Levels of LBC from newborns with RDS are significantly lower (p = 0.14) than the count in healthy neonates. the average result of the LBC among infants with RDS was of 18.83± 6.5, while the average result of the LBC among the group of healthy newborns was 40.87± 3.59. These results correspond to previous studies conducted from samples taken from amniotic fluid during amniocentesis [14] and in fact show that the sample obtained via a vaginal surface swab is not inferior to a sample taken during amniocentesis assuming the sample is not bloody.

In addition, there are significant differences (p = 0.005) between the groups regarding gestational age. as expected, at earlier gestational ages, fetal lung maturity is lower and there are more cases of RDS. Among the group of neonates with RDS, the average week of pregnancy was 33 (with a standard deviation of 0.35) while in the healthy neonates, the average was 34.35 (SD = 0.15). This average is in accordance with previous studies [13,14] and moreover, it validates the logic of treating with injections of celestone for fetal lung maturity up to 34 weeks and not after. This study found a new threshold value for determining lung maturity: in an LBC test obtained from the vaginal surface, with a 95% confidence interval, an LBC greater then 36.06 indicates pulmonary maturity, while a value of 33 or less indicates a risk of RDS. The intermediate values from the ACOG guidelines were narrowed down considerably.

Secondary Outcomes

Another interesting statistic from this study is the difference between the weight of the newborn and RDS. The logistic regression test distinguished between infants of the same birth weight, but with different values for RDS (yes/no). In our study, it seems that there is no connection whatsoever between the birth weight of the newborn alone and the chances of developing respiratory distress syndrome, but there is a definite link between IUGR (newborn weight less than 10% by weight appropriate for gestational age) and RDS. That is, IUGR itself, regardless of the absolute weight of the newborn, appears to be a risk factor for RDS. This finding has been noted in previous studies regarding the effects of IUGR on newborns [15]. It is possible that reduced renal function impairs the normal manufacturing process of surfactant. This issue requires more thorough investigation, and it is not included of our study. Jaundice was also found more often among infants with RDS. This finding also requires more in-depth investigation, because we do not know the causal relationship between these two phenomena. There was no association between maternal age, maternal fever during labor, gender or cesarean delivery and neonatal RDS. It should be noted that as part of our data collection we did not always find the indication for the Caesarean section (whether due to previous Caesarean, fetal lie, maternal distress or other reasons). This issue also requires more careful attention and is not considered in this study.

Strengths and Weaknesses

Strengths of this study are that the LBCs were all performed using the same method, within 24 hours, in the same laboratory and with the same equipment. Thus, the multivariate calibration and material handling were effectively neutralized. However, this study has several weaknesses: the incidence of RDS found in our study was significantly lower than we expected for the calculated sample size (p = 0.2). This assumption was based on the proportion of different reports in the literature regarding the incidence of RDS in premature infants (who formed most of the study population) [13]. Looking back this can be attributed to several biases in information:

1. The exclusion criteria were cases of multiple pregnancies, which are characterized by lower gestational ages and lower lung maturity.

2. Cases of quick, premature births were apparently excluded (it is likely that in such cases no vaginal sample was taken due to the rapid delivery). These births did not have time to receive a complete course of celestone, and most cases are characterized by higher incidence of RDS.

Nevertheless, the incidence of RDS in this study (5.2%) is sufficient for investigating the degree of correlation between the LBC and incidents of RDS and for the examination of other variables evaluated in the study. In addition, this is a small, retrospective study, with all the limitations of this method. We have no information about selection of patients who underwent the test and therefore no way to anticipate and neutralize selection bias. our control of confounding variables is incomplete and we relied on reports in the medical records as they were recorded and available to us.

Limitations- Potential Biases

Selection Bias: All samples were taken at Meir Hospital, which serves the residents of the Sharon and the surrounding area only. It will be possible to overcome this bias by comparing the data to other hospitals in a different location in future research. Another source of selection bias is maternal characteristics. There is inconclusive evidence that women with gestational diabetes have higher LBC values compared to women with normal pregnancies, even though newborns of diabetic women tend to have more complications, including RDS [7]. We overcame this bias by including gestational diabetes in maternal demographic data and stratifying accordingly.

Confounding Information: bloody samples may potentially affect the number of lamellar bodies because platelets may be counted as lamellar bodies by the machine. Therefore, bloody samples were excluded from our study. In addition, it is unknown in the literature whether the presence of meconium in the amniotic fluid may affect c the values of the LBC, so we included these cases in the regression. To account for these biases, we used a multivariate model that was corrected for additional variables such as maternal fever, amnionitis, gestational diabetes, meconium fluid, neonatal fever or diagnosis of neonatal respiratory infection [16-19].

Significance

As noted above, the issue of management of delivery in the case of premature rupture of membranes (PPROM) is debated in the literature. PPROM and conservative management imperils the fetus to vaginal infection on one hand, while on the other hand early active delivery risks complications of prematurity, as noted above. Although there is debate about the necessity of testing fetal lung maturity prior to birth (as some say it is only in one of several systems that need to mature), we believe that the immaturity of the pulmonary system is associated with significant morbidity and mortality and therefore has great significance. We believe that in borderline cases of PPROM in advance pregnancies, as described above, an LBC test from a vaginal swab could help tip the scales as to the timing of delivery. The test is inexpensive, fast, safe, requires no special training, and as we have shown in our study, is reliable and effective in determining the extent of fetal lung maturity. Although most dilemmas regarding delivery are relevant in the later weeks of pregnancy (34-36), and this study examined a much wider range, we believe that it is a starting point for a deeper examination of this issue. Larger, prospective, multicenter randomized studies are required to substantiate this conclusion.

For more Articles on: https://biomedres01.blogspot.com/

 

Influence of the Ratio of the Grinding Mixture of the Triticale Grain and Hemp Seeds on the Grain-Forming Ability of the Triticale-Hemp Grain Mixtures

Introduction

Products of processing grain crops in the form of various types and varieties of flour make up a significant share in the diet of the population of our country. However, the chemical composition of food products obtained on the basis of traditional technologies is characterized by an insufficient balance in nutritional value and biological efficiency [1]. In this regard, it is required to develop food products with increased nutritional and nutritional value on a grain basis with the addition of oilseeds (hemp) [2-5]. Hemp seeds are of high nutritional value, while they are rich in essential fatty amino acids (EFAs), vitamins A, D , E and group B, trace elements (calcium, iron, sodium), dietary fiber [6,7]. In terms of nutritional value, only soy can compete with hemp, while the quality of proteins in hemp seeds is much higher, they are close in composition to human blood proteins. In addition, hemp seeds are an environmentally friendly product, since no herbicides are used on hemp crops - this plant, due to its vitality, copes well with diseases and pests on its own.

A characteristic feature of hemp seeds is a high fat content from 32.5 to 51.5% with a content of polyunsaturated fatty acids (ω- 3, ω-6 families) from 40 to 50% and a high protein content from 20 to 30% with a well-balanced amino acid content. composition [8,9]. The ratio of polyunsaturated Essential Fatty Acids (EFAs) ω-3 (linoleic acid), ω-6 (linolenic acid) in hemp seed oil is among the most optimal for the human body and is recommended for use by people suffering from cardiovascular diseases and disorders of the nervous system. The need to enrich triticale flour with polyunsaturated fatty acids is also justified by the fact that ɷ-3 and ω-6 fatty acids are not synthesized in the human body due to the lack of an enzyme system [1-3,6-9]. Hemp processed products (oil, cake, meal, flour, protein powder) are increasingly used in food production as a source of nutrients containing essential amino acids and fatty acids, incl. polyunsaturated ɷ3 and ɷ6 series, in sufficient quantity and ratio to meet the physiological needs of a person [1-3,6-12]. The purpose of our research is to establish the effect of different ratios of the grinding mixture of triticale grain and hemp seeds on the yield of intermediate grinding products.

Materials and Methods of Research

As an object of research, we used grain of winter triticale of the Nemchinovskaya 56 variety harvested in 2021 and hemp seeds of the Surskaya variety of the same year . Grain of triticale variety “Nemchinovskaya 56” was bred by breeders of the laboratory of selection and seed production of field crops of the Federal State Budgetary Educational Institution of Higher Education RGAUMSHA named after K.A. Timiryazev and has good flour-grinding properties. The main physico-chemical and chemical parameters of the initial triticale grain are as follows: humidity - 11.6%, nature - 730 g / l, weight of 1000 grains - 47.9 g, ash content - 1.88%, protein content - 12.3%, gluten content - 21.8%, gluten quality - 85 units of the device, vitreousness - 32% and the falling number - 229 seconds. The processing of the triticale-hemp grinding mixture of various ratios and the control grain of triticale to determine the coarse-forming ability of the intermediate grinding products was carried out at the Nagema laboratory grinding mill with cut rollers.

The main mechanical and kinematic indicators of the Nagema mill with cut rollers are as follows: productivity - up to 150 kg / h, speed of the rapidly rotating roller 4.5 m /s, differential 1.5, location of the corrugations back to back, the number of corrugations on the 1st linear centimeter - 5 pieces, flute slope 7%. The gap between the rollers on the I torn system was 0.5 mm, on the II torn system - 0.25 mm, on the III torn system - 0.15 mm, on the IV torn system - 0.1 mm and the V torn system - 0.09 mm . As a Hydrothermal Treatment (HTT) in the preparation of triticale grains for laboratory grinding of a grinding mixture of triticale grains and hemp seeds, cold conditioning was used as the most common method and the cheapest way. At the same time, only the triticale grain was subjected to the TRP, because hemp seeds are not recommended to be moistened due to their high fat content.

Research Results

When conducting research to determine the effect of different ratios of the grinding mixture of triticale grain and hemp seeds on the groat-forming ability of intermediate grinding products , laboratory grinding of triticale- hemp grain grinding mixtures was carried out in the ratios of 92.0 / 8.0%, 94.0 / 6.0 %, 92.0/8.0% and 90.0/10.0%. Adding more than 10% of hemp seeds to the grinding mixture is not recommended due to the fact that the cut grinding rollers of the machine begin to clog, as well as polyamide sieves in the screening for sifting intermediate grinding products due to the increased fat content. During laboratory grinding, all 5 of 5 tattered, groat-forming systems were modeled. The obtained experimental data on the yield of intermediate products of grinding triticale-hemp grain grinding mixture and triticale-hemp flour in a ratio of 96%:4% are presented in Table 1. As can be seen from Table 1, when adding 4% hemp seeds to the grinding triticale-hemp grain mixture , the yield of intermediate grinding products in the form of coarse dunst products was 84.1%, incl. 9.2% triticale-hemp flour.

Table 1: Yield of intermediate products of grinding triticale-hemp grain grinding mixture and flour in a ratio of 96%:4%.

Table 2 presents the obtained experimental data on the yield of intermediate grinding products and triticale-hemp flour when grinding triticale-hemp grain grinding mixture in a ratio of 96%:4%. As can be seen from Table 2, when adding 6% hemp seeds to the grinding triticale-hemp grain mixture , the yield of intermediate grinding products in the form of coarse dunst products was 85.4%, incl. 9.9% triticale-hemp flour. Table 3 presents the obtained experimental data on the yield of intermediate grinding products and triticale-hemp flour when grinding triticale-hemp grain grinding mixture in a ratio of 96%:4%. As can be seen from Table 3, when adding 8% hemp seeds to the grinding triticale-hemp grain mixture , the yield of intermediate grinding products in the form of coarse dunst products was 85.8%, including 8.7% triticalehemp flour. Table 4 presents the obtained experimental data on the yield of intermediate grinding products and triticale-hemp flour when grinding triticale-hemp grain grinding mixture in a ratio of 90%:10%. As can be seen from Table 4, when adding 10% hemp seeds to the grinding triticale-hemp grain mixture , the yield of intermediate grinding products was 89.5%, incl. 10.5% triticalehemp flour.

Table 2: The yield of intermediate products of grinding triticale-hemp grain grinding mixture and flour in a ratio of 94%:6%.

Table 3: The yield of intermediate products of grinding triticale-hemp grain grinding mixture and flour in a ratio of 92%:8%.

Table 4: Yield of intermediate products of grinding triticale-hemp grain grinding mixture and flour in a ratio of 96%:4%.

Table 5 presents the obtained experimental data on the yield of intermediate grinding products and triticale flour when grinding the control grain of triticale without adding hemp seeds. As can be seen from Table 5, when grinding the initial control grain of triticale of the Nemchinovskaya 56 variety, the yield of intermediate grinding products in the form of coarse dunst products and triticale-hemp flour was 81.1%. Thus, adding from 4% to 10% of hemp seeds to the grinding triticale-hemp mixture leads to an increase in the yield of intermediate grinding products, from which wheat-hemp flour will be obtained later on grinding systems, from 0.9% to 34.7% by compared with the control sample of wheat.

Table 5: The yield of intermediate products of grinding the original triticale grains grade “Nemchinovskaya 56”.

Findings

a. Thus, according to the results of the studies, it was found that the addition of 4% hemp seeds to the grinding triticalehemp grain mixture yielded intermediate grinding products of 84.1%, incl. 9.2% triticale-hemp flour, when 6% hemp seeds were added to the grinding triticale-hemp mixture , the yield of intermediate grinding products was 85.4%, incl. 9.9% triticalehemp flour , when 8% hemp seeds were added to the grinding triticale-hemp mixture , the yield of intermediate grinding products was 85.8%, including 8.7% triticale-hemp flour, when 10% hemp seeds were added to the grinding wheathemp mixture , the yield of intermediate grinding products was 89.5%, incl. 10.5% triticale-hemp flour.

b. When grinding the initial control grain of triticale of the Nemchinovskaya 56 variety, the yield of intermediate grinding products was 81.1%, incl. 11.6% triticale flour.

c. It was found that the addition of 4% to 10% hemp seeds to the grinding triticale-hemp mixture leads to an increase in the yield of intermediate grinding products by 3.0-8.4% compared to the yield of intermediate grinding products of their control triticale grain. At the same time, after grinding on grinding systems of intermediate grinding products, the yield of wheathemp flour increases from 0.9% to 4.7% compared to the control sample of triticale.

For more Articles on: https://biomedres01.blogspot.com/

 

Efficient Assessment of a Low-Cost Device to Avoid the Risk of Implant Migration in Anterior Lumbar Interbody Fusion Surgery and Lumbar Disco Arthroplasty

Introduction

The anterior approach technique to treat lumbar spine pathologies had a high rate of complications in the past, such as bleeding, retroperitoneal injury, retrograde ejaculation, and implant migration. [1-3] With the new implants, retractors, and trained access surgeons, we observed an increase in the number of surgeries by anterior approach associated with a lower rate of complications [4,5]. The anterior access technique allows wide exposure of the intervertebral disc with a larger area of the arthrodesis. Besides, it increases intradiscal height, causing an indirect decompression of the nerve roots and lordosis gain, improving the biomechanics of the lumbar spine and providing a faster recovery in the patient’s postoperative period. [4-6] The anterior access route for the surgical treatment of lumbar spine pathologies has been increasing its indication, given its numerous advantages over the classic posterior approach, the improvement of the access surgeon, and the better evolution of implants [4]. Following this evolution, we observed a small incidence of anterior migration of the implants used. However, despite being a small number, they can lead to devastating complications for the patient due to the specific characteristics of the local anatomy [7]. For more than ten years, the same surgeon team of a spine clinic in Sao Paulo state, Brazil, has been working hard to improve the approach technique and minimize post-surgical complications in the patient. They have used a cancellous screw with a meager cost and provides additional stability as an anterior lock [1,5-7]. Thus, this study describes using a 6.5 mm simple cancellous screw placed on the lower vertebral plateau in the surgery spine segment to avoid anterior migration of arthroplasty and lumbar interbody implants.

Methods

We documented the clinical outcomes of 89 patients who underwent arthrodesis and arthroplasty performed by the same team of surgeons from a medical center in Sao Paulo, Brazil. The FMABC Ethics committee approved the study with the number 37120920.1.0000.0082. The data presented maintain the confidentiality of the patient’s identity.

Eligibility criteria

We selected patients who had pain in the lumbar region associated or not with irradiation to the lower limbs, with good bone quality confirmed by bone densitometry, calcium, and vitamin D metabolism. The diagnosis was also confirmed by traditional tests such as magnetic resonance imaging for specific etiologic diagnosis, dynamic radiography to assess the flexibility of the lumbar region, and the presence or absence of segmental instability. Electroneuromyography to document the presence of preoperative radiculopathy and possible pre-existing neurological deficits. In both techniques, arthrodesis, and arthroplasty, patients with indications for surgical treatment are refractory to clinical therapy for more than one year. For anterior arthrodesis, we included patients with degenerative lumbar disc disease between the L3- L4 levels; L4-L5; L5-S1 in patients over 60 years old, patients who have moderate to severe facet arthrosis, gross instability, previous surgery approached via a posterior approach and as a complement to 360° arthrodesis. We excluded patients with minimal or no degree of arthrosis of the facet joint without evidence of spondylolisthesis or pars defect. In the case of arthroplasty, we included patients aged between 20 and 55 with low back pain with or without irradiation to the leg who had failed conservative treatment for more than one year. They confirmed the diagnosis of degenerative disc disease by magnetic resonance imaging [8]. We excluded patients with significant or symptomatic facet disease, degenerative spondylolisthesis > 3 mm or pars defect, osteoporotic disease, and previous anterior or posterior lumbar fusion. Individuals with bone involvement such as infection or tumor and conditions that would be against indication for surgery were also excluded [8]. The primary implants used in the surgical interventions described in this analysis are Intersomatic CAGE (Double Locking Cage ALIF (Figure 1); Thoracolumbar Interbody Fusion Kili (Figure 2); M6-L Artificial Lumbar Disc (Figure 3), and the Cannulated Screw (Figure 4).

Figure 1: Double Locking CAGE ALIF.

Figure 2: Thoracolumbar Interbody Fusion ALIF.

Figure 3: M6 L Artificial Lumbar Disc.

Figure 4: Cannulated Screw.

Surgical Procedure

After placing the lumbar disc prosthesis or inter somatic CAGE, it is necessary to minimize the migration risk of these implants, using a screw to reinforce anterior stability. [9] To place the screw, we performed a bone tunnel with a 3.2 mm drill or a Stillman wire (bone tunnel performed manually with an orthopedic hammer without using a drilling machine) centered on the body’s midline and the apex of the lower vertebral plateau of the instrumented level. We followed the anterosuperior direction from the vertebral plateau to the posteroinferior monocortical region, as shown in Figure 5. At the time of bone drilling, we used the ‘’C’’ arm of the radioscopy directed in anteroposterior to identify the vertebral body midline and handled to aid in the depth of the drill or Stillman wire insertion not to invade the opposite cortex and the endplate. [9,10] We considered slight variations of 10° to 15° of angulation acceptable and minor changes in the entry point in the anterolateral direction. Some access surgeons prefer to place the screw 5 to 10 mm lateral to the midline at the levels of l3-l4 and l4-l5 to avoid possible protrusions under the inferior vena cava. To introduce the cancellous screw with washer into the body of the first sacral vertebra (S1), we used the 70° angle concerning the upper plateau of the body of S1 due to its trapezoidal anatomy (Figure 6). [9,10] After the bone tunnel, we measured the screw with the conventional gauge of the large fragment box that varies between 25 mm to 40 mm, followed by the tapping of 6.5 mm and then the insertion of the cancellous screw total thread of 6.5 mm with washer under fluoroscopy control as seen in Figure 7. The screw works as a locking tool to prevent the anterior migration of the instrumented material performed by locking the washer (Figure 8).

Figure 5: Screw implant inserted at 45º from the vertebral plateau.

Figure 6: Screw planning.

Figure 7: Positioning of the ‘’Cancellous Screw with Washer’’.

Figure 8: Fluoroscopy image of the screw, front and lateral view.

Results

Of the total patients (89) who underwent surgery, 49 were treated by the Anterior Lumbar Interbody Fusion (ALIF) technique, and the other 40 by arthroplasty. Table 1 shows the frequency of patients who underwent ALIF. Three of them suffered migration of the implants, one case in a Stand-Alone approach to 2 levels of instrumentation and two migrations of Stand Alone in 3 levels instrumented. The patients who underwent arthroplasty (40 patients and 71 implants) were performed with stabilization of the ‘’Cancellous Screw with Washer’’. Three patients presented complications related to implant migration, as illustrated in Table 2.

Table 1: Frequency of Patients with Anterior Lumbar Interbody Fusion.

Table 2: Frequency of Patients who underwent arthroplasty.

Discussion

Out of the 89 patients who underwent surgery, six (6,7%) experienced implant migration. The complications with anterior arthroplasty occurred among the first patients who underwent the surgical intervention. The clinical team has discussed it profoundly and thinks that perhaps its short experience with those implants could affect the outcome. We also have managed the hypothesis that the complications of anterior arthroplasty migration were even more related to problems inherent to the patient and the medical indication than to the surgical technique and the implant used. Furthermore, we believe the complications were caused by: a) A significant fracture of the upper vertebral plateau of the instrumented lower vertebra, possibly due to inadequate indication of the procedure, as the patient was over 55 years old. Late plateau fracture (35 days postoperatively) evolved with instability and anterior expulsion of the implant.

b) An anterior migration due to segmental instability was only identified intraoperatively in a patient with a large extruded herniated disc, treated anteriorly for decompression and arthroplasty, followed by a posterior microsurgical approach to review the spinal canal. Segmental instability was diagnosed in the posterior approach, and it was no longer possible to change the technique for arthrodesis of this segment. We waited for the postoperative evolution, with implant migration after falling from its height on the 21st postoperative day.

c) A prior migration was due to the patient’s previous obesity, her initial refusal to perform lumbar arthrodesis, and her inability to lose weight during the first 60 postoperative days. She evolved with anterior migration of the implant 61 days after surgery, after a minor fall from its height.

It is worth noting that anterior migration, both the ALIF and the arthroplasty, can cause arterial compression, venous compression, or compression of the right or left ureters. Depending on the level accessed during surgery, arteriovenous compression can compress the aorta, the vena cava, or the iliac arteries and veins. Arterial compression can progress to acute arterial occlusion accompanied by tissue ischemia, or subacute partial arterial compression, with consequent vascular claudication. Venous compression can cause total venous occlusion with deep vein thrombosis. It can trigger pulmonary embolism and death, where a partial venous compression with hemodynamic involvement of more than 70% of the vessel lumen will start venous stasis and chronic venous insufficiency. Concerning extrinsic compression of the ureters by the migrated implant, post-renal acute failure could lead to renal failure. It occurred in cases of total obstruction; or dilation of the ureter and pyelocaliceal system due to a ureter partial block, with consequent chronic renal failure. Resolute treatment for chronic low back pain due to degenerative disc disease (DDD) is challenging and controversial. According to the Visual Analogue Scale and Oswestry Scale [The Oswestry Disability Index (ODI)] there has been a significant improvement in performing surgical treatment with anterior arthrodesis at 1 to 2 levels for patients with more than six months of clinical therapy due to DDD [8].

After the complications of the initial learning curve of the use of the lumbar arthroplasty technique, it was decided to combine the ‘’Cancellous Screw with Washer’’ with the arthroplasty technique in all other subsequent patients, totaling 30 more patients with implantation of M6-L arthroplasty, without any case of subsequent migration. From a historical point of view, there is evidence that the cancellous screw was used as a retaining device for the iliac crest or femoral diaphysis graft in inter somatic arthrodesis performed via the anterior approach. We observed that it did not follow a pattern of insertion, positioning, size, or angulation for its purpose. There was not a protocol for its usage [9]. Because of these circumstances, and in the absence of a clinical protocol, surgeons Marcondes and Dias have implemented and mastered the screw reinforcement technique to avoid the risk of displacement of the implants in spinal surgeries. With an experience of more than ten years of performing this procedure, these doctors have accumulated evidence of the patients benefiting from this technique. This particular surgical approach of doctors Marcondes and Dias is known and recognized by the clinical community.

Intersomatic arthrodesis performed via the anterior approach has biomechanical advantages compared to posterior, oblique, or lateral approaches [1]. It is a considerably young procedure and has been increasingly adopted since 1960 [11]. Due to the direct access to the anterior spine, the intervertebral disc space is visualized, a complete discectomy is performed, and intervertebral spacers are implanted. It has resulted in an exponential growth in the number and variety of devices for the anterior lumbar approach over the last five years. [12,13] We know that 80% of the load is absorbed in the anterior portion of the spine, making instrumentation in this region essential when performing segmental arthrodesis. A literature review comparing the biomechanics of different approaches for inter somatic fusion (MIS TLIF expandable with conventional TLIF and ALIF) reported that the most rigid fixation in flexion-extension and axial rotation was ALIF associated with bilateral pedicle screw fixation. However, other studies tended to perform arthrodesis using an isolated anterior approach. Its advantage is shorter surgical time, less intraoperative bleeding, hospital stay reduction, and decreased complication, for example, pseudarthrosis rate varying around 6.5% and reoperation around 2.4% [10].

After arthrodesis surgery, we highlight the disc disease of the adjacent level as a late complication; its prevalence is still not well documented, making it one of the main criticisms in opposition to performing a movement-preserving surgery (total disc arthroplasty). Studies show increased stress on the facet joint and disc, causing high mobility at levels adjacent to the fused segments. In recent studies, we have observed a prevalence of symptomatic patients with degenerative disease of the adjacent level ranging from 5.2% to 18.5%, with instrumentation for arthrodesis, an extension of the fusion, iatrogenic sagittal balance, previous degenerative disc disease adjacent to arthrodesis and young patients with high functional demand [10]. Despite a limited sample of 89 patients analyzed in this study, there was a significant decrease in complications related to the migration of the Stand- Alone implant, both CAGE ALIF and total disc prosthesis, when supplementation of the anterior fixation with ‘’Cancellous Screw with Washer’’.

Studies report that the anterior approach has higher implant migration rates. With the removal of stabilizing structures of the anterior column associated with the lordotic anatomy of the lumbar spine, there is a greater probability of anterior migration of the implant in the postoperative period [10]. In the late patient’s follow-up, we observed that the screw does not change the mobility of the implant in the case of arthroplasties and does not result in a significant increase in the cost of the procedure. In addition, the anterior approach has been advocated due to the minimal formation of fibro-scar tissue, absence of trauma to the paravertebral musculature, and posterior ligament structures, with the main advantage being the gain of lumbar segmental lordosis and the recovery of sagittal alignment. [3,14-20] The current study showed the use of the ‘’ Cancellous Screw with Washer’’ in cases of double ALIF Stand Alone locks at two or more levels. In cases of Lumbar Arthroplasty, it can contain the need for a posterior approach and prevent complications from anterior implant migration.

Conclusion

The cancellous screw with large fragments - 6.5 mm, with washer is a low-cost fixation instrument, and its implantation does not affect bleeding and surgical time. With more than ten years of executing this procedure, Marcondes and Dias advise its use for ALIF Stand Alone in two levels or more, and all arthroplasty cases in one or two levels, considering the low cost and the prevention of anterior migration of the implant, decreasing the reoperation rate. The clinical team of Marcondes and Dias are currently carrying out a biomechanical study to deeply understand other aspects of the screw stabilizing effect.

For more Articles on: https://biomedres01.blogspot.com/