Medico-legal Conclusions Caused by Misevaluation of the Schmorl’s Node, Which is Rarely Seen in Children (Case Report)

1Bahçeşehir University Faculty of Medicine, Department of Forensic Medicine, İstanbul, Turkey 2Van Yüzüncü Yıl University Faculty of Medicine, Department of Neurosurgery, Van, Turkey 3Tokat State Hospital, Tokat, Turkey 4Ondokuz Mayıs University Faculty of Medicine, Department of Pediatric Radiology, Samsun, Turkey 5Van Yüzüncü Yıl University Faculty of Medicine, Department of Forensic Medicine, Van, Turkey


INTRODUCTION
Schmorl's node (SN) that was firstly defined in 1858 by von Luschka and was named in 1927 by Christian Georg Schmorl and commonly seen in the lumbar spine and lower part of thoracic vertebral column was described as disruption of the cartilaginous end plate and herniation of the nucleus pulposus into the vertebral body in the period after losing of nuclear material through the cartilage plate (1)(2)(3)(4)(5). The pathogenesis of SNs has been explained by four theories to be "embryological developmental defects", "degeneration due to aging", "pathological changes due to diseases involving the vertebral column" and "effects of acute and chronic traumas on vertebral column" (2). However, the etiology of SNs has not yet been fully elucidated (3,4). The prevalence of SN in adults reported as from 20% to 76% in different autopsy studies (6-9). Stäbler et al. (10) defined to be 38% incidence of SN in radiological examinations in adults (10). Sonne-Holm et al. (11) reported that 5% of males and 3% of females had SNs in the radiological examination performed on 4151 persons between the ages of 18-92 (11). The incidence of SNs in children was not defined however; few cases were reported in literature investigated by us (12)(13)(14)(15). It is extremely important to make accurate medical descriptions of traumatic lesions that constitute a source for legal forensic reports and are considered legal evidence. A defective or incomplete identification may make the legal solution difficult. Because, this inaccurate identification causes misinterpretations of the experts or issuing a wrong report which may change the direction of the judicial investigation lead to false convictions or acquittal decisions (16). In this article, a SN case which is rarely seen in children and was mistakenly described as a "traumatic vertebral compression fracture" was submitted and the forensic medical problems that may be caused by this misidentification were discussed.

CASE REPORT
A 12-year-old boy was injured by impact of a car in a traffic accident. On his first admission to the state hospital, he complained of pain in his head, right shoulder, lumbar region and hip. Physical examination revealed hematoma under the scalp in frontal region and dermal abrasions of right arm and at back of the body. In the computed tomography (CT) examinations, right clavicle fracture, humeral supracondylar fracture, lumbar vertebra fracture and sacrum fracture were defined. There was no internal organ injury in the child. In the lumbar vertebrae magnetic resonance imaging (MRI), the height loss was thought to be associated with SN in anterior part of the upper plateau of the L5 vertebra, transformation of red marrow into yellow marrow around this area, slight reduction in the intensity of the L4-L5 intervertebral disc were seen. The patient was transferred to the orthopedic clinic after 36 hours of intensive care. The patient was discharged four days after the incident following the non-surgical treatment in this clinic. In the medical board report prepared by physical therapy clinic of the same hospital about two months after the incident, 25% to 50% traumatic collapse fracture in the corpus of L5 vertebra was defined and 13% disability rate was reported. In the CT report of the lumbar vertebra prepared approximately four months after the event, limbus vertebra in anterior segment of the L5 vertebra corpus, height loss in anterior section secondary to limbus vertebra, posterior arch fusion defect in posterior section of the S1 vertebra corpus were described. According to the forensic report prepared by the forensic medicine specialist and the orthopedics and traumatology specialist about six months after the incident, there was no causality between the height loss in the L5 vertebra corpus and car-accident and it was associated with a disease sequela which was defined as a SN in the radiology report. In lumbar vertebra CT report prepared by the radiology department of a university hospital in 11 th month following incident, slight height loss (compression fracture?) at upper end plate of the L5 vertebra were seen. On the same day, the patient applied to the forensic outpatient clinic for a disability report. Physical examination revealed no functional disturbance, and healing findings in right clavicle, supracondylar humeral and sacrum fractures were seen in the radiological examination. The patient's neurological examination was normal and there was no neurovascular deficit. CT and MRI of the lumbar vertebra of the patient, which were both recently obtained and obtained at the time of the event, were examined together by forensic medicine, neurosurgery, radiology and pediatric radiology specialists (Figure 1, 2). In the radiological examinations made on the date of the incident, although mild collapse was seen in the anterior-upper part of the L5 vertebra, the absence of hematoma and/or edema around the bony lesion, and the presence of blunting and sclerosis at the edges of this lesion excluded a new fracture that occurred at the time of the event. Moreover, this lesion preserved almost the same appearance in radiological examinations 11 months after the event. According to these findings obtained in this multi-disciplinary radiological examination, we decided that lumbar vertebra lesion was associated with SN and there was not a causality between lumbar vertebra lesion and caraccident.

DISCUSSION
Fractures of the spine in children and adolescents are rare due to stiffness of vertebral end plate and vascular supply of annulus fibrosus up to age of 20 (17)(18)(19). In the pediatric population, vertebral fractures represent 0.2-3% of all fractures and structural lesions represent 0.6-3% of all spinal damages (17,19). The etiology of vertebral compression fractures is generally associated with traumas, osteoporosis and neoplastic infiltrates in elderly and some diseases (20,21). In children, primary cause of vertebral compression fractures were defined as traumas such as motor vehicle accidents, falls and sports injuries. Also, 5 th lumbar vertebra was defined as the least affected spinal region in these traumas (19,22). In MR imaging, soft tissue and/or marrow edema is accepted as one of the evidences of traumatic vertebral fracture occurred in recent (23,24). While the presence of hematoma can be evaluated in favor of acute traumatic fractures, in the absence of hematoma, the distinction of traumatic or nontraumatic is difficult (21). SNs in radiographic and tomographic images is defined as "usually typical lesions with a small, focal, rounded form, and radiolucency in the subchondral bone of the vertebral body, broad-based at the vertebral plateau and with varying degrees of adjacent reactive sclerosis" (1). In the present case, depiction of the slight collapse in the anterosuperior part of the L5 vertebra in the radiological examinations taken in event date, the absence of hematoma and/or edema around bone lesion, and the presence of blunting and sclerosis at the edges of this area were exclusion criteria for a recent traumatic lesion occurred on the incident date. Mistakenly description of a SN case as a "traumatic vertebral compression fracture" and establishing a causality between this lesion and the traffic accident to which the person was exposed, can lead to some important forensic medical problems. During the assessment of injuries according to the Turkish Penal Code, establishing a causality between fracture of the vertebral bone and car accident will be an aggravating factor on punishment of driver. Likewise, this error will also affect the degree of disability of the victim and cause the defendant to pay more compensation. For this reason, clinicians and radiologists should be more careful in the evaluation of forensic cases and should not refrain from consulting other specialists including forensic medicine experts in cases where they cannot make decisions. As seen in the presented case, although radiological diagnoses that are terminated with a question mark in forensic cases are preferred by radiologists to protect themselves, they should be minimized as they constitute important handicaps in the decision-making process in preparing forensic reports.

CONCLUSION
In this article, a SN case was reported which is rarely seen in children. It was described as "traumatic collapse fracture" and "compression fracture?" in two radiology reports. Before our multidisciplinary review, clinicians made an erroneous conclusion based on these radiology reports and found a causality between this lesion and a traffic accident and defined the disability rate as 13%. In acute spinal traumas, MRI has a very important role in determining soft tissue damage around bone lesions seen on CT, and the presence or absence of these damages plays an important role in the establishment of the causality in forensic cases. As in our case, forensic reports to be issued without establishing a causality may result in erroneous punishment or compensation. Consequently, this paper emphasizes the importance of multidisciplinary approach for refraining from misevaluation of a medico-legal case.

Ethical Declaration
Informed consent was obtained from the participant and Helsinki Declaration rules were followed to conduct this study. Peer-review: Internally peer-reviewed.