Doctors' Diagnostic Accuracy for Infant Head Shapes is Only 14.1%: Keio University Study Reveals the Limits of Visual and Tactile Examination

Japan Medical Company Inc. (Chuo-ku, Tokyo; Hideaki Ono, Representative Director and CEO; hereinafter "the Company") announces that the results of joint research with full-time lecturer Yoshiaki Sakamoto of the Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, have been published in the *Journal of the Japan Pediatric Society* (Vol. 130, No. 4). As a result of a large-scale survey of 327 pediatricians, the percentage of correctly distinguishing whether an infant's head deformity was a "disease requiring surgery (craniosynostosis)" or a "deformity due to positional preference eligible for helmet therapy" using only visual inspection and palpation was a mere 14.1%. This study raises the alarm on current medical practices where visual-only diagnoses are prevalent, and proposes the importance of early visits to specialized medical institutions capable of imaging diagnostics.

The Impact of this Announcement: 86% Missed in a "Diagnostic Blind Spot"

Currently, in the field of helmet therapy which is becoming popular among general practitioners and family doctors, the common flow for addressing infant head shapes has been: "First, be examined by a local pediatrician, and if the family doctor determines there is a 'suspicion of pathological deformity,' helmet therapy is provided or a referral to a specialized medical institution is made." However, the results of this study have highlighted the limitations of the "gatekeeper function in primary medical institutions," which is the premise for infant cranial checkups and helmet therapy.

The Hard Truth Where Even "Suspecting" is Difficult: The 14.1% accuracy result conversely indicates an 85.9% probability risk that doctors will misidentify a disease requiring surgery as "just a positional deformity." There is also the risk of misdiagnosing a condition as treatable with a helmet and inappropriately applying helmet therapy. Using only visual appearance and tactile feel (inspection and palpation), precise differentiation is extremely difficult, even for specialists in infant head shapes such as pediatric neurosurgeons and pediatric plastic surgeons.

Impossible to Confirm Without "Images," Even for Specialists: Specialists in pediatric neurosurgery and pediatric plastic surgery who participated in this study and have experience operating on craniosynostosis scored an accuracy rate of 49.0%. While higher than the 14.1% accuracy of pediatricians, all specialists unanimously insisted that "X-rays or CT scans are necessary for a definitive diagnosis."

Redefining the Medical Care Flow: Under the flow where general practitioners and clinic doctors "refer to a specialized medical institution if craniosynostosis is suspected," there is a possibility that it may be too late because a "suspicion" is never raised in the first place. If there are concerns about the head shape or an interest in helmet therapy, this suggests that "visiting a medical institution equipped with imaging diagnostic equipment and specialists from the very beginning, before judging the presence or absence of suspicion," may become the new common sense to protect the healthy development of babies.

Summary of the Paper

Changes in a baby's head shape can be caused by lifestyle habits or by diseases that require specialized treatment such as surgery. While it is difficult for parents to tell the difference, it is not uncommon in medical settings for the cause to be judged "only by appearance or tactile feel."

In this study, 11 life-size models of infant heads reproducing differences in head shape were created, and a large-scale blind survey was conducted at conference venues where pediatricians were asked to visually and tactilely examine "head models of pathological cranial deformities."

Background of the Low Accuracy Rate: The accuracy rate of the 327 pediatricians was 14.1%. The accuracy was uniformly low regardless of years of service or experience in providing helmet therapy, proving that diseases cannot be detected by rules of thumb alone.

Trends in Incorrect Answers: In particular, "unilateral lambdoid synostosis" closely resembles deformities caused by positional preferences in appearance, and the error rate reached 29.7%. Missing this carries the risk of inhibiting development and growth, and may lead to serious situations. In fact, in other countries, large-scale lawsuits have occurred due to misdiagnoses related to head shapes.

The Need for Centralization: Compared to Europe and the United States, where diagnosis and treatment are concentrated in specialized facilities, the paper suggests that in Japan, general practitioners often handle initial diagnoses, and the lack of training and imaging equipment is a structural challenge.

Significance of the Research: Designing the Care Flow is Crucial, Assuming Difficulty in Differentiation

This study clarified that differentiation by pediatricians purely through visual inspection and palpation is insufficient, suggesting the possibility that craniosynostosis may be missed. The paper concludes that in order to provide reliable differential diagnosis and appropriate treatment, it is necessary to establish a medical care system that includes specialist referrals and the use of imaging diagnostics.

While there is high parental interest in infant head shapes, without proper differentiation and care pathways, the timing for connecting to necessary specialized treatment may be affected. This study is expected to serve as foundational information for considering an appropriate provision system for cranial checkups by visualizing the current state of differentiation.

Keio University School of Medicine's Full-time Lecturer Sakamoto and the Company will address the challenges described in this paper by