A case of a pineal parenchymal tumor of intermediate differentiation with bifocal lesions differentiated by negative placental alkaline phosphatase in the spinal fluid.

Placental alkaline phosphatase (PLAP) in the spinal fluid is helpful for the diagnosis of intracranial germinomas. Bifocal lesions involving the pineal and pituitary regions have also been reported as characteristic findings of intracranial germinomas. We present a rare case of a 15-year-old boy with a pineal parenchymal tumor of intermediate differentiation (PPTID) with bifocal lesions negative for PLAP. Magnetic resonance imaging of the brain revealed bifocal mass lesions in the pineal and suprasellar regions and non-communicating hydrocephalus. We initially suspected a germinoma based on imaging findings, but all tumor markers, including PLAP, in the spinal fluid were negative. Based on these results, germinoma was considered less likely, and an endoscopic third ventriculostomy and endoscopic tumor biopsy were performed for diagnosis. The histopathological diagnosis was PPTID, corresponding to World Health Organization grade 3, in both pineal and suprasellar specimens. A craniotomy for tumor removal was performed, resulting in total resection. PLAP is known to have high sensitivity and extremely high negative predictive value for germinomas. Although bifocal lesions highly suggest germ cell tumors, there are exceptions, as in the present case. This case suggests that PLAP measurements are useful for differentiation, leading to appropriate treatment strategies.

Brainstem cavernous hemangioma with improvement of Holmes tremor on excision.

An 8-year-old boy presenting with left-angle paralysis, tremor in upper and lower extremities, and diplopia was diagnosed with hemorrhage from a mesencephalic cavernous hemangioma. He underwent hemangiomectomy through the occipital transtentorial approach 4 weeks post-hemorrhage, after which Holmes tremor (HT) markedly reduced. A year later, hemangioma has not recurred; he is now independent in his daily activities. Early intervention in the subacute stage allows for the complete removal of brainstem cavernomas (BSCs), with minimal risk of complications or sequelae. Proper timing and surgical approach for BSCs can prevent re-bleeding and improve HT after an initial hemorrhage, without any lasting negative consequences.

Helmet therapy efficacy and its prediction in Japanese infants with positional plagio- and brachycephaly.

PURPOSE: To provide additional information on optimal start times and therapeutic effectiveness based on treatment outcome of Japanese infants with positional plagio- and brachycephaly (PPB) receiving cranial molding helmet therapy (CMHT). METHODS: In this retrospective cohort study, data from a 3D head scanning system was analyzed from 2173 Japanese infants who completed CMHT. Anterior and posterior symmetry ratio (ASR and PSR) and longitudinal to transverse diagonal ratios (LD/TDR) were calculated based on skull shape at helmet design and at completion of therapy. The outcomes were evaluated using the regression analysis and a predictive model using cranial parameters was developed. RESULTS: The earlier the start of therapy, the greater the therapeutic effect on ASR, PSR, and LD/TDR (ASR, -0.134 percent points (ppt)/day; PSR, -0.086 ppt/day; and LD/TDR, -0.131 ppt/day). In the predictive model, in addition to starting age of the therapy, sex (male), the degree of deformity of the head (DoD) (moderate and severe), quadrant volume, PSR, and head circumference at the start of treatment also had a positive effect on changes in ASR, DoD (moderate and severe), ASR, LD/TDR and transverse diameter for PSR, sex (male), DoD (moderate), quadrant volume, PSR, and head circumference for LD/TDR. CONCLUSION: The starting age of therapy had a relatively smaller contribution to outcome effects. Applying the cranial parameter obtained at the start of treatment to the predictive model helps to predict the effect of CMHT and whether PPB can be treated with CMHT in infants of older age.

Screen-printed wearable skin surface pH sensor for real-time monitoring of the buffering capacity of human skin.

This study demonstrated for the first time that skin surface pH can be monitored in real-time, using a screen-printed wearable pH sensor, to evaluate the buffering capacity of the human skin. The screen-printed pH sensor was composed of a polyaniline-based pH-sensitive electrode and a nitrocellulose membrane-based liquid junction type of Ag/AgCl reference electrode. This sensor showed a reliable and reversible potentiometric response to pH with long-term potential stability. Intermittent monitoring of the buffering capacity of skin surface pH demonstrated the reliability of the proposed wearable pH sensor, which was comparable to that of a commercially available flat-tip pH sensor. We found that contact of the wearable pH sensor with the subject's skin via aqueous electrolyte solutions was necessary for the sensor to continuously monitor the skin surface pH while sustaining the natural buffer capacity of the human skin surface.

Endoscope-assisted Trans-lamina Terminalis Resection of Chordoid Glioma at the Third Ventricle: A Case Report.

As per the 2021 World Health Organization (WHO) Classification of Tumors of the Central Nervous System, chordoid glioma (CG) is defined as a slow-growing glial neoplasm categorized as grade II tumor. This tumor is primarily located in the anterior part of the third ventricle, often adheres to important surrounding structures, and is hemorrhagic in nature. Therefore, dissecting this tumor is extremely difficult. In this study, we present the case of a 44-year-old man who initially complained of mild headache and was diagnosed with a homogeneous gadolinium-enhanced lesion in the third ventricle via magnetic resonance imaging. The pathological diagnosis based on his biopsy at the previous hospital was CG. The patient demonstrated no neurological deficit at that time, but the tumor had gradually grown, hydrocephalus appeared 2 years after the tumor was detected, and the patient developed short memory disorder and daytime sleepiness. We resected the tumor via the anterior interhemispheric trans-lamina terminalis approach using a microscope and an endoscope. The residual tumor at the blind spot of the microscopic view was resected under an angled rigid endoscopic view using dedicated tools for transsphenoidal surgery. The tumor was grossly resected, and the histopathological diagnosis was CG. Postoperative neurological findings included slight memory disorder and hypothalamic adrenal dysfunction. No tumor recurrence was reported 3 years post resection. The endoscope-assisted anterior interhemispheric trans-lamina terminalis approach was determined useful for CG resection with minimal surgical complications and without tumor recurrence.

Systemic Metastasis of Pediatric Diffuse High-grade Astrocytoma: A Case Report.

Extracranial brain tumor metastases are extremely rare. The etiology, pathophysiology, and clinical progression of systemic metastatic brain cancer remain to be elucidated. We encountered a case of pediatric diffuse high-grade astrocytoma in a four-year-old girl with subcutaneous and lymph node metastases. Numerous metastatic lesions emerged, progressed rapidly, and were difficult to manage despite temozolomide (TMZ) administration. The patient underwent repeated surgical resection for these lesions. Conversely, the primary intracranial lesions responded well to TMZ for some time. However, the patient died 15 months after the initial diagnosis. Extracranial metastasis and highly varying effects of chemotherapy were the characteristic clinical features in this case. Our analysis did not reveal definitive histopathological and molecular factors contributing to this presentation. The lack of notable molecular pathological features illustrates the unpredictability of glioma metastasis, and the treatment for extracranial metastasis remains unknown. A gene panel analysis revealed several genetic aberrations, including PDGFRA, PIK3CA, and NBN mutations. As it is impossible to resect all frequently and rapidly progressing lesions, we stress that the prognosis of metastatic brain tumors is undoubtedly poor if these tumors are refractory to existing treatments, including chemotherapy.

Difference in Clinical Phenotype, Mutation Position, and Structural Change of RNF213 Rare Variants Between Pediatric and Adult Japanese Patients with Moyamoya Disease.

It is unclear how rare RNF213 variants, other than the p.R4810K founder variant, affect the clinical phenotype or the function of RNF213 in moyamoya disease (MMD). This study included 151 Japanese patients with MMD. After performing targeted resequencing for all coding exons in RNF213, we investigated the clinical phenotype and statistically analyzed the genotype-phenotype correlation. We mapped RNF213 variants on a three-dimensional (3D) model of human RNF213 and analyzed the structural changes due to variants. The RNF213 p.R4810K homozygous variant, p.R4810K heterozygous variant, and wild type were detected in 10 (6.6%), 111 (73.5%), and 30 (19.9%) MMD patients, respectively. In addition, 15 rare variants were detected in 16 (10.6%) patients. In addition to the influence of the p.R4810K homozygous variant, the frequency of cerebral infarction at disease onset was higher in pediatric patients with other rare variants (3/6, 50.0%, P = 0.006) than in those with only the p.R4810K heterozygous variant or with no variants (2/51, 3.9%). Furthermore, on 3D modelling of RNF213, the majority of rare variants found in pediatric patients were located in the E3 module and associated with salt bridge loss, contrary to the results for adult patients. The clinical phenotype of rare RNF213 variants, mapped mutation position, and their predicted structural change differed between pediatric and adult patients with MMD. Rare RNF213 variants, in addition to the founder p.R4810K homozygous variant, can influence MMD clinical phenotypes or structural change which may contribute to the destabilization of RNF213.

Corrigendum: Photodynamic therapy for malignant brain tumors in children and young adolescents.

[This corrects the article DOI: 10.3389/fonc.2022.957267.].

Efficacy of the pedicle trapezius muscle flap for the multisurgical removal of pediatric posterior fossa anaplastic ependymoma.

OBJECTIVE: Exceedingly refractory, pediatric anaplastic ependymoma in many cases requires multisurgical removal. The high risk of poor wound healing and CSF leakage especially at the posterior fossa make this tumor difficult to treat. CASE: A 9-year-old girl has had 4th ventricular anaplastic ependymoma since the age of 3. She experienced tumor removal 8 times including 4 posterior fossa craniotomies because tumors were disseminated not only to the posterior fossa but also to the cerebral hemispheres. She also underwent a dermal graft using a free flap. She experienced CSF leaks and meningitis frequently because the wound healing was poor. We performed a dermal flap closure using a pedicle trapezius muscle flap with a plastic surgeon when we performed the 5th tumor removal. RESULT: We achieved complete wound closure in spite of broad deficiencies in subcutaneous and epidermal tissues. After that, recurrences of posterior fossa tumors presented within a short term, and tumor removal via an incision of a pedicle trapezius muscle flap was performed without recurrence of CSF leaks and meningitis. DISCUSSION AND CONCLUSION: For the first time, we are able to report on the efficacy of using the pedicle trapezius muscle flap for multisurgical removal of pediatric posterior fossa anaplastic ependymoma. The muscle flap was found to be effective because of the multiple surgeries expected, and the pedicle trapezius muscle flap was found to be resilient to multiple surgical procedures. Although advantageous, the dorsal scapular artery which is required for flap creation is actually difficult to harvest. Compared to a flee flap, the pedicle trapezius muscle flap maintains vascular supply. Furthermore, this technique has the possibility of being applied to defective dura mater closure that cannot be watertight due to multiple surgeries. However, it is very important to inform the patient's family not only about the improved efficacy of surgery, but also to raise awareness on consequential cosmetic issues.

Selective surgical mamillo-thalamic tract disconnection in hypothalamic hamartoma results in complete disappearance of gelastic seizures.

Hypothalamic hamartoma is a less common condition characterized by the several types of epileptic seizures including the gelastic type. It is reported that gelastic seizures are resistant to medical treatment with anticonvulsants, while stereotactic thermocoagulation or Gamma Knife radiosurgery are effective for seizure control. Here, we report an individual case where direct surgical resection disconnecting hypothalamic hamartoma from mammillothalamic tract resulted in complete disappearance of gelastic seizures without deterioration of cognitive function. A 6-year-old boy developed gelastic seizures at the age of 2 and suffered from precocious puberty. Anticonvulsants including carbamazepine and zonisamide failed to control seizures. The patient underwent direct division of the mammillothalmic tract by removal of hypothalamic hamartoma partially via anterior interhemispheric approach. It was observed that gelastic seizures disappeared completely after the surgical treatment without any endocrine and cognitive dysfunction for a follow-up period of 14 years. The mammillothalamic tract which connects anterior nucleus of thalamus and mammillary bodies plays a key role in gelastic seizures related to hypothalamic hamartoma. In this case, we disconnected the hamartoma specifically from the mammillary bodies and not from the rest of hypothalamus. Effectively, it enabled permanent control of seizures. This result shows that fibers connecting other hypothalamic structures and the dorsomedial nucleus of thalamus are not involved in gelastic seizure propagation from the hypothalamic hamartoma. When surgical treatment of hypothalamic hamartomas is performed it has high morbidity associated with hypothalamic disorders. Therefore, disconnection between hypothalamic hamartoma and mammillary bodies presents a possibility of reducing hypothalamic damage. Surgical disconnection between hamartoma and mammillothalamic tract carries minimal hypothalamic injury risk and our results suggest that it has the potential of seizure control for intractable gelastic seizures with less complications.

Description of the first definitive Corythosaurus (Dinosauria, Hadrosauridae) specimens from the Judith River Formation in Montana, USA and their paleobiogeographical significance.

Despite the long history of research in the late Campanian Judith River Formation in northern Montana, most of the vertebrate fossils are represented by fragmentary remains, making precise taxonomic identifications difficult. Contrary to this, the partially contemporaneous Dinosaur Park Formation, Alberta, Canada is known for its tremendous fossil preservation, permitting rigorous studies of dinosaur diversity, evolution, and biostratigraphy. Hadrosaurids comprise one of the most abundant dinosaur clades in the Dinosaur Park Formation, but taxonomic affinities of hadrosaurid specimens remain poorly understood in the Judith River Formation. Corythosaurus is the most common hadrosaurid in the Dinosaur Park Formation and, to date, has been restricted to this formation. This study reports the first definitive Corythosaurus specimens from the Judith River Formation, which were discovered on two private ranches in northern Montana. The attribution of the most complete skeleton to Corythosaurus is indicated by: wide crest-snout angle, presence of premaxilla-nasal fontanelle, dorsoventrally expanded nasal, laterally exposed ophthalmic canal of the laterosphenoid, and tall neural spines. A second specimen preserves a large ilium that can be positively identified as Corythosaurus based on its associated skull, which is now in private hands. The specimens were recovered from the Coal Ridge Member of the Judith River Formation, which is approximately time equivalent to the Dinosaur Park Formation. Thus, the discovery of Corythosaurus in the Judith River Formation extends the biogeographic range of this genus and establishes a framework for future interformational biostratigraphic studies of Late Cretaceous dinosaur faunas in North America.

Transient neurological events in childhood moyamoya disease.

OBJECTIVE: Patients sometimes experience transient neurological events (TNEs) during the early postoperative period after revascularization surgery for childhood moyamoya disease. The clinical background and pathophysiology of TNEs remain unclear. This study aimed to evaluate the incidence rate of TNEs and discuss the factors associated with pediatric moyamoya disease. METHODS: The authors retrospectively reviewed 110 cerebral hemispheres of 61 pediatric patients younger than 15 years who were treated from 2011 to 2020. All children underwent either simple double-direct or combined revascularization surgery. Of these 61 patients, 52 underwent bilateral surgery and 9 underwent unilateral surgery. The authors calculated the incidence of TNEs in accordance with a previously reported TNE definition. Cerebral blood flow (CBF) was evaluated in all eligible cases with xenon CT immediately after revascularization surgery. RESULTS: The incidence rate of TNEs in patients with childhood moyamoya disease was 26.4%. TNEs occurred after an average (range) of 6.26 (2-12) days postoperatively without triggers, and all identified TNEs spontaneously resolved within 2 weeks. The most common symptoms were dysarthria, facial palsy, and numbness around the mouth, followed by sensory disturbance of the upper extremities. The presence of focal hyperperfusion on xenon CT performed immediately after revascularization surgery was strongly correlated with the incidence of TNEs (p = 0.0001). Focal hyperperfusion was observed in 43 of 110 operative sides (39.1%). Notably, only 25.6% of patients with focal hyperperfusion showed numerical global hyperperfusion. In addition, a decrease in CBF compared with the thalamic region in the contralateral side was observed in TNE-affected cases (p = 0.0443). CONCLUSIONS: TNEs occurred more frequently in childhood moyamoya disease patients than expected. The clinical background, including symptoms, timing, and duration, was almost identical to TNEs in adults. Focal hyperperfusion, rather than numerical global hyperperfusion, was strongly correlated with the incidence of TNEs. Furthermore, the authors advocate the notion that a clinical course where symptoms occur without triggers may be a unique characteristic of TNEs, especially in childhood moyamoya disease.

Novel BCL11B truncation variant in a patient with developmental delay, distinctive features, and early craniosynostosis.

Intellectual developmental disorder with dysmorphic facies, speech delay, and T-cell abnormalities (MIM # 618092) is a congenital disorder derived from pathogenic variants of the B-cell leukemia/lymphoma 11B gene (BCL11B). Several variants have been reported to date. Here, through comprehensive genomic analysis, a novel BCL11B truncation variant, NM_138576.4(BCL11B_v001): c.2439_2452dup [p.(His818Argfs*31)], was identified in a Japanese male patient with developmental delay, distinctive features, and early craniosynostosis.

Photodynamic therapy for malignant brain tumors in children and young adolescents.

Photodynamic therapy (PDT) targets tumor cell remnants after resection. Here, we evaluated the feasibility of PDT for malignant brain tumors in children and young adolescents. This was a single-center, non-randomized, phase I/II clinical study. The primary endpoints were the safety of treatment with talaporfin sodium (TS) (phase I) and overall survival (OS) after PDT (phase II). The secondary endpoint was progression-free survival (PFS) after PDT. The TS dose was determined by dose escalation from 10 to 20 to 40 mg/m2 for every three cases starting from the initial enrolled case. Eight patients with a mean age of 170.2 months (129-214 months) at the time of PDT received nine procedures with a mean follow-up duration of 16.8 months (1-42 months) after PDT. Histopathological diagnoses included supratentorial anaplastic ependymoma (n = 2), anaplastic astrocytoma (n = 1), diffuse midline glioma with H3K27M mutation (n = 1), glioblastoma (n = 3), and pediatric high-grade glioma (n = 1). The outcome was survival in five patients and death in three patients. Recurrence occurred in six of the eight patients; the remaining two were recurrence-free after PDT. Therefore, OS and PFS were calculated as 21 and 6 months, respectively. Seizures and fevers, which were likely surgery-related symptoms, were commonly observed. Photosensitive skin rashes or liver dysfunction, which are common adverse effects in adults, were not observed. Our results showed that TS can be used safely in children at doses comparable to those used in adults, as there was no major complication associated with TS administration. However, we cannot make a definitive conclusion about the efficacy of PDT because of the small number of participants. Accumulating cases was difficult because of the rarity of pediatric brain tumors and the difficulty in making a preoperative differential diagnosis, considering the wide range of histopathological findings. Moreover, the psychological stress associated with light-shielding management in pediatric patients was more severe than initially expected. In conclusion, TS at doses comparable to those used in adults may be safe for use in children and young adolescents between the ages of 6 and 20 years. However, further studies are needed to clarify its efficacy.

One-Piece Frontoorbital Osteotomy With a Small Supraorbital Burr-Hole to Protect Against Intraoperative Dural Lacerations.

ABSTRACT: This paper aims to describe a new technique of 1-piece frontoorbital osteotomy with a small supraorbital burr hole, which resulted in improved safety during osteotomy of the anterior skull base. An 11 × 4 mm burr hole was created at the center of the orbit above the superior orbital rim using an "eyebrow key-window approach." Extradural dissection from the nasion to the medial side of the sphenoid ridge was performed through this hole, and dissection of the lateral side of the sphenoid ridge was completed from the edge of the coronal osteotomy. Osteotomy along the zygomaticofrontal and sphenofrontal sutures were performed using an oscillating saw with secure protection of the dura. Between December 2019 and June 2020, 3 patients with unilateral coronal craniosynostosis underwent 1-piece frontoorbital advancement with the eyebrow key-window approach. The median age was 11 months (8-15 months), median operation time was 249 minutes (244-255 minutes), and the average blood transfusion was 10.8 ml/kg (0-18 ml/kg). No complications were observed, and the technique was associated with improved safety of osteotomy around the anterior skull base for 1-piece frontoorbital advancement.

Prevention of venous thromboembolism in pregnant women with congenital antithrombin deficiency: a retrospective study of a candidate protocol.

BACKGROUND: The best thromboprophylaxis for pregnant women with congenital antithrombin deficiency (CAD) is controversial. OBJECTIVE: To clarify the effectiveness of a protocol for venous thromboembolism (VTE) prevention in pregnant women with CAD. METHODS: Women at high risk of VTE were administered antithrombin concentrate and heparin after conception, whereas those at low risk of VTE were administered heparin alone until delivery. All women received antithrombin concentrate at delivery except for one who was diagnosed with CAD. RESULTS: Ten women had CAD, including one in the high-risk group and nine in the low-risk group. No women had VTE at delivery as per the protocol for VTE prevention. Almost all women had increased antithrombin activity before delivery followed by maintenance at ≥ 70% due to antithrombin concentrate administration. VTE prophylaxis during and after delivery was successful in all women with CAD. However, one woman in the low-risk group did not receive heparin and developed VTE induced by severe hyperemesis at 9 gestational weeks, before the diagnosis of CAD. Women in the high-risk group received antithrombin concentrate after delivery but had increased D-dimer levels at postpartum. CONCLUSIONS: Our protocol to prevent VTE in pregnant women with CAD is safe and effective.

C-reactive protein level predicts need for medical intervention in pregnant women with SARS-CoV2 infection: A retrospective study.

AIM: To make effective use of the limited available hospital space during the Coronavirus disease 2019 (COVID-19) pandemic, we conducted this study to investigate the laboratory indices that identify pregnant women with SARS-CoV2 infection who require medical intervention. METHODS: We carried out a retrospective analysis of pregnant women positive for COVID-19 who were admitted to Hokkaido University Hospital from September 2020 to June 2021. Medical interventions included oxygen supplementation, systemic corticosteroids, or supplemental liquids to treat infection-related symptoms. RESULTS: Forty-two infected pregnant patients were admitted to the hospital, half of whom required medical intervention (n = 21). Fever, C-reactive protein (CRP), and platelet count are all associated with need for medical intervention. Of the 32 patients with a fever of ≥37.5°C on days 0-3 after onset of syndromes, 22 (69%) continued to have a fever on days 4-6, of which 19 (86.4%) required medical intervention. CRP level on days 4-6 predicted the presence or absence of medical intervention (area under the receiver operating characteristic curve = 0.913), with a sensitivity of 81% and specificity of 100% at a CRP cutoff of 1.28 mg/dL. CONCLUSIONS: The need for medical intervention in pregnant patients can be predicted with high accuracy using a CRP cutoff of 1.28 mg/dL on days 4-6 after onset of syndromes. The presence of fever also may be an easy marker for selecting subjects who need or will need therapeutic intervention. These could be an effective triage method to determine appropriate indications for the hospitalization of pregnant women in future outbreaks.

Breath-holding spells after endoscopic third ventriculostomy in a post-ventriculoperitoneal shunted patient.

Breath-holding spells (BHS) are commonly observed in children as a result of an autonomic nervous system disorder triggered by crying, emotional distress, or pain. There are several types of BHS and cyanotic type is one of them. We encountered a case of 3-year-old girl who presented with a delayed adaptation period and BHS 2 weeks after an endoscopic third ventriculostomy (ETV). She experienced severe headache due to increased intracranial pressure (ICP) during the delayed adaptation period, which may have contributed to the onset of BHS. Management of BHS warrants treatment of the symptoms and removal of the causative factors; in our case, intensive pain control and resolution of the increased ICP after the adaptation period were effective. While BHS are usually described as a benign condition that improves spontaneously, we highlighted the importance of recognizing and monitoring atypical symptoms such as BHS in pediatric cases.

Association between pre-pregnancy body mass index and gestational weight gain and perinatal outcomes in pregnant women diagnosed with gestational diabetes mellitus: The Japan Environment and Children's Study.

AIMS/INTRODUCTION: We investigated the association between gestational diabetes mellitus (GDM) and perinatal outcomes stratified by pre-pregnancy body mass index (BMI) and/or gestational weight gain (GWG). MATERIALS AND METHODS: Data from the national birth cohort in the Japan Environment and Children's Study from 2011 to 2014 (n = 85,228) were used. Japan uses the GDM guidelines of the International Association of Diabetes and Pregnancy Study Groups. The odds ratios (ORs) of perinatal outcomes were compared between women with and those without GDM. RESULTS: The OR (95% confidence interval) of having a small for gestational age infant in the GDM group with a pre-pregnancy BMI of ≥25.0 kg/m2 and insufficient GWG (<2.75 kg) was 1.78 (1.02-3.12). The OR of having a large for gestational age infant of the same BMI group with excessive GWG (>7.25 kg) was 2.04 (1.56-2.67). The OR of hypertensive disorders of pregnancy was higher in women with a BMI ≥18.5 kg/m2 in the GDM group than in the non-GDM group. CONCLUSIONS: Large for gestational age and hypertensive disorders of pregnancy were associated with pre-pregnancy BMI and GWG in either normal weight or overweight/obese women, and the relationship was strengthened when GDM was present. Women with GDM and a BMI of ≥25.0 kg/m2 are at risk of having small for gestational age and large for gestational age infants depending on GWG.

Growth variability, dimensional scaling, and the interpretation of osteohistological growth data.

Osteohistological data are commonly used to study the life history of extant and extinct tetrapods. While recent advances have permitted detailed reconstructions of growth patterns, physiology and other features using these data, they are most commonly used in assessments of ontogenetic stage and relative growth in extinct animals. These methods have seen widespread adoption in recent years, rapidly becoming a common component of the taxonomic description of new fossil taxa, but are often applied without close consideration of the sources of variation present or the dimensional scaling relationships that exist among different osteohistological measurements. Here, we use a combination of theoretical models and empirical data from a range of extant and extinct tetrapods to review sources of variability in common osteohistological measurements, their dimensional scaling relationships and the resulting interpretations that can be made from those data. In particular, we provide recommendations on the usage and interpretation of growth mark spacing/zonal thickness data, when these are likely to be unreliable, and under what conditions they can provide useful inferences for studies of growth and life history.