IMMATURITY OF CONNECTIVE TISSUE AS A CAUSE OF DAMAGE TO THE DURAL MINING IN NEWBORN WITH EXTREMELY LOW BODY WEIGHT

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JUSTIFICATION

According to Order N 1687n of the Ministry of Health and Social Development of Russia dated December 27, 2011 “On medical criteria for birth, the form of the birth document and the procedure for its issuance,” “medical criteria for birth” are: gestation period of 22 weeks or more, with the child’s body weight at birth 500 grams or more , (or less than 500 grams for multiple births). In cases where the gestation period is less than 22 weeks or the child’s body weight at birth is less than 500 grams, or the child’s body weight is unknown and the body length is less than 25 cm, the birth criterion will be a life expectancy of more than 168 hours after birth (7 days) [1] .

Official statistics indicate that the number of cases of premature births is increasing worldwide. In the United States, the rate of preterm birth is approximately 11%, in Europe it ranges from 5% to 7%. Despite advances in obstetric care, the rate of prematurity has not decreased over the past 40 years [13]. Extremely low birth weight (ELBW) newborns are more likely to die during the first week of life [2, 13, 14].  The mortality rate of newborns with ELBW is 8-13 times higher than the same indicator for timely births. [3, 5] Extreme prematurity is one of the leading risk factors for the development of birth trauma. The brain and spinal cord are most often damaged during childbirth [4, 6, 7, 8, 14].Damage to the nervous system is a reason for initiating criminal and civil cases against obstetricians and gynecologists due to improper provision of medical care. Problems of liability of medical workers are becoming increasingly relevant at the present stage of development of society.The American College of Obstetricians and Gynecologists (ACOG) reported that 80% of its members have been sued, with an average of three lawsuits per member. Many of the highest-profile medical malpractice verdicts, often in the tens of millions of dollars, involve birth injuries [15].Currently, pathologists and forensic experts experience significant difficulties in examining such newborns, since before the entry into force of the above legislation, such newborns were not subjected to autopsy. According to foreign literature, the frequency of autopsies of deceased patients in neonatal intensive care units is decreasing. Post-mortem magnetic resonance imaging is used as a complement or replacement for autopsy [16].Modern Russian-language literary sources describe the biomechanisms of birth injuries in full-term newborns with all types of fetal presentation, as well as operative delivery, and scientific and practical developments of new methods for sectional access to the jugular ganglia of the vagus nerve and vertebral arteries have been introduced [9, 10, 11, 12].  

TARGET

To identify the distinctive features of the structure of the connective tissue of the dura mater (DRM) in newborns with ELBW at birth and full-term newborns. To establish a connection between the structural features of the dura mater and its damage during childbirth.

MATERIALS AND METHODS

Study design

A retrospective, selective analysis of archival autopsy materials, materials of criminal and civil cases was carried out regarding the deaths of newborns with ELBW and full-term newborns, with a proven fact of birth trauma. The study was carried out at the bases of the Krasnoyarsk Regional Bureau of Forensic Medical Examination (KKBSME) and the KGBI "Bureau of Forensic Medical Examination" of the Ministry of Health of the Khabarovsk Territory (Bureau of the Forensic Medical Examination of the Ministry of Health of the Khabarovsk Territory).

Eligibility

CriteriaInclusion criteria: archival material of autopsies, materials of criminal and civil cases regarding deaths of newborns with ELBW and full-term newborns, with a proven fact of birth trauma.

Criteria for non-inclusion and exclusion: archival material of autopsies, materials of criminal and civil cases regarding deaths of premature newborns with a birth weight of more than 1000 grams, with severe malformations, full-term newborns without an established diagnosis of birth injury, stillborn fetuses.

Conditions

The study of archival material from autopsies, materials from criminal and civil cases, histological glass preparations/paraffin blocks was carried out at the bases of the KKBSME and the Bureau of Medical Examinations of the Ministry of Health of the KhK for the period from 2020 to 2023.

Duration of the study

The study is a retrospective selective analysis of archival materials; an estimate of the duration of the study is not informative.

Description of medical intervention

A retrospective selective analysis of autopsy materials, materials of criminal and civil cases was carried out regarding the deaths of newborns with ELBW and full-term newborns. The method and causes of delivery in the comparison group and the main group were assessed.  A macro- and microscopic assessment of hemorrhages in the dura mater, which formed as a result of birth trauma, was carried out, identifying distinctive structural features of the dura mater and morphometry of collagen fibers in both groups in 30 fields of view of the microscope.The material under study underwent standard histological processing, was embedded in paraffin blocks, and histological microslides were made. Histological sections were stained with basic and acidic dyes (hematoxylin-eosin). Viewing, studying, description and microphotographs were made on a NIKON ECLIPSE E200 microscope. Polarization microscopy to determine the composition of collagen fibers in the dura tissue, followed by morphometry of type 1 collagen, was carried out using an ocular insert. All received data is systematized and registered.

Main outcome of the study

Morphometry of type 1 collagen fibers in the dura mater was carried out in deceased newborns with ELBW and full-term newborns in 30 fields of view of the microscope. It has been established that the number of type 1 collagen fibers in the dura mater in newborns with ELBW is significantly less than in the dura mater in full-term newborns, which causes its immaturity and damage during any type of birth.

Additional study outcomes

Additional expected outcomes from the medical intervention study were not observed.

Subgroup analysis

As part of the implementation of the assigned tasks, a retrospective selective analysis of cases in the materials of autopsies, criminal and civil cases was carried out. Two groups were formed: a main group and a comparison group.  The main group consisted of 30 deceased newborns with ELBW from 500-1000 g, regardless of the method of delivery. The control group consisted of deceased full-term newborns weighing from 2900-3600 g, with a proven fact of birth trauma, regardless of the method of delivery , in the amount of 30.

Methods for recording outcomesTo record outcomes, the operating shell Microsoft Windows Professional 2010 and Excel were used; calculations were carried out using the SPSS v.26 package.

Ethical review

The Independent Ethics Committee decided: “to approve the conduct of a candidate’s dissertation on the topic “Biomechanism and forensic medical assessment of birth injuries in newborns with extremely low body weight”, in the specialty: 3.3.5 - “Forensic Medicine”, at the Department of Forensic Medicine of the Federal Institution of Internal Affairs of the State Budgetary Healthcare Institution MO MONIKA named after. M.F. Vladimirsky".  Extract from the minutes of meeting No. 15 dated October 7, 2021

Statistical analysis

Principles for sample size calculation: The sample size was not pre-calculated.Methods of statistical data analysis: calculations were carried out using the SPSS Statistics v.26 package, Microsoft Excel; classical statistical methods were used: Mann-Whitney statistical test; Indicators at p <0.001 were considered statistically significant.

RESULTS              

Objects (participants) of the study

The material for the study totaled 60 cases in both groups. The main group included autopsy materials, materials of criminal and civil cases from 30 newborns with ELBW from 500-1000 g, gestation period from 22-27 weeks. The cause of premature birth in this group was acute uteroplacental insufficiency, with the development of rapid labor, or requiring emergency caesarean section in 60% and 40% of cases, respectively.The comparison group included autopsy materials, materials of criminal and civil cases from 30 full-term newborns weighing from 2900-3600 g, with a proven fact of birth trauma. Delivery in the control group was carried out both through the natural birth canal and by elective caesarean section.

Main results of the study

In all studied cases, in newborns with ELBW, severe intradural hemorrhages were found in the dura mater, localized in the falx, sinus drainage area, and cerebellar tentorium. A minimal severity of the “step sign” was found, with minor hemorrhages in the pia mater. The dura mater from the area of ​​the tentorial velum, falx and sinus drainage area is represented by loose connective tissue, consisting predominantly of type 3 collagen fibers, with the inclusion of a small amount of type 1 collagen fibers. When polarizing microscopy, type 3 collagen is represented by short fibers with no anisotropy at a microscope magnification of x400. Type 1 collagen is represented by single small bundles of fibers with a clear polarization effect at microscope magnification x 400. Anisotropy in polarized light was detected in no more than 2-5% of collagen fibers. (Fig. 1 A, B)Comparing the results, it was revealed that in full-term newborns in the comparison group, the severity of subarachnoid hemorrhages in the projection of the sutures corresponds to the severity of damage to the septal parts of the dura mater.   Histological examination of the dura mater of similar localizations consists of dense fibrous connective tissue. (Fig. 2) Anisotropy in polarized light is at least 30-50%.When carrying out statistical analysis, a comparison was made of the minimum, maximum and average values ​​of the amount of type 1 collagen in the main group and the comparison group. The indicators were tested for compliance with normal distribution using the Kolmogorov-Smirnov tests (with Liljefors significance correction) and Shapiro-Wilk tests. In both groups, the hypothesis of compliance with the normal distribution was rejected, therefore, structural indicators (median and quartiles designated Me (Q25%; Q75%)), minimum and maximum values ​​were used to characterize the indicators.The nonparametric Mann-Whitney test was used to compare groups in terms of the percentage of mature fibers. (Table 1) In the main group, the minimum value for 30 fields of vision varies from 2% to 5%, the median is 2%. In the comparison group – from 30% to 40%, median – 39%. The maximum value for 30 visual fields varies in the main group from 3 to 5% (median is 4.5%), in the comparison group - from 40 to 50% (median - 50%).The average value in the main group varies from 2.5 to 4.5% (median - 3.5%), in the main group - from 35 to 45% (median 40%). The main group and the comparison group differed in terms of the presence of type 1 collagen fibers statistically significantly (p <0.001). A diagram of the range of the average percentage of mature fibers in the main group and the comparison group is presented. (Fig. 3)

Additional Study Findings              

No additional outcomes were identified in this study. Adverse eventsNo adverse events were identified during the study.

DISCUSSION

Summary and discussion of the main result of the study

During the birth process, compressive forces act on the baby's head in various directions. Increasing stresses lead to tension in the dura mater duplicatures - the sails of the cerebellar tentorium and falx [10, 11].  These structures are connective tissue consisting of cells, basic or amorphous substance and collagen fibers. [17]Severe intradural hemorrhages in the dura mater duplications in the main group indicate their overextension due to displacement of the skull bones at the sutures. The dura mater in premature newborns is represented by loose connective tissue, with the presence of only 3 - 5% of mature type 1 collagen fibers, in contrast to full-term newborns, their dura mater is represented by dense connective tissue with the presence of mature type 1 collagen fibers in an amount of 30 to 50%.The identified differences and structural features of the connective tissue of the dura mater duplications in newborns with ELBW indicate its morphofunctional immaturity, which sharply reduces the strength characteristics and inevitably leads to trauma during any type of childbirth. These differences help explain the cause of damage to the septal parts of the dura mater in premature newborns with ELBW.

Limitations of the study

No limitations were identified within the scope of the study.

CONCLUSION

Due to the pronounced physiological immaturity of the connective tissue of the dura mater in newborns with ELBW, inevitable damage occurs, regardless of the method of delivery and with technically correct obstetric tactics. Consequently, this injury is an injury to a painfully altered organ and should not be qualified by a forensic expert assessment of the severity of harm to health.

ADDITIONAL INFORMATION

Source of financing. The authors declare that there was no external funding for the study. This study was not supported by any external sources of funding.

Conflict of interest. The authors declare that there are no obvious or potential conflicts of interest related to the publication of this article. The authors declare that they have no competing interests.

Authors' participation. The authors confirm that their authorship meets the international ICMJE criteria (all authors made significant contributions to the development of the concept, conduct of the research and preparation of the article, read and approved the final version before publication). The largest contribution is distributed as follows: E.Yu. Gorun - data collection, drafting of the manuscript, scientific editing of the manuscript; S.L. Parilov - data collection, scientific editing of the manuscript; S.L. Parilov, A. V. Maksimov - review and approval of the final version of the manuscript.

Acknowledgments None.

TABLES and FIGURES

Fig. 1. Dura mater of a deceased newborn with ELBW, sinus drainage area.  Yellow filter.

“A” Staining: hematoxylin-eosin, magnification: 10x10.

“B” Staining: hematoxylin-eosin, polarization; magnification: 10x10. (photo from personal archive)

Fig. 2. The dura mater of a deceased full-term baby, the sinus drainage area. Blue filter. Staining: hematoxylin-eosin, magnification: 10x10. (photo from personal archive)

Fig. 3. Comparison of average values ​​of type 1 collagen fibers across 30 fields of view in the study and the control groups.

Table 1. Research sample of groups. Comparison of the amount of type 1 collagen in the main group and the control group.

% mature fibers in 30 fields of view	Main group			Comparison group			р
	Minimum	Maximum	Me (Q25%; Q75%)	Minimum	Maximum	Me (Q25%; Q75%)
Minimum value for 30 fields of view	2,0	5,0	2,00 (2,00; 3,00)	30	40	30,00 (30,00; 40,00)	<0,001
Maximum value over 30 fields of view	3,0	5,0	4,50 (4,00; 5,00)	40	50	50,00 (50,00; 50,00)	<0,001
Average value over 30 fields of view	2,5	4,5	3,50 (3,00; 3,63)	35,0	45,0	40,00 (40,00; 45,00)	<0,001

作者简介

Ekaterina Y. Gorun

Moscow Regional Research Clinical Institute named after M.F. Vladimirsky

编辑信件的主要联系方式.
Email: katuhka30@mail.ru
ORCID iD: 0000-0002-7008-2975
SPIN 代码: 4298-5402

-

俄罗斯联邦, 129110, Russia, Moscow, Shchepkina street, 61/2.

Sergey L. Parilov

Moscow Regional Research Clinical Institute named after M.F. Vladimirsky

Email: parilov.s@mail.ru
ORCID iD: 0000-0001-9888-4534

MD, Dr. Sci. (Med.), Associate Professor

129110, Russia, Moscow, Shchepkina street, 61/2.

Aleksander V. Maksimov

Moscow State Regional Pedagogical University

Email: mcsim2002@mail.ru
ORCID iD: 0000-0003-1936-4448
SPIN 代码: 3134-8457

MD, Dr. Sci. (Med.), Associate Professor

俄罗斯联邦, Moscow

参考

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