Helmet Therapy for Infant Head Deformity

The clinic is run by three board-certified plastic surgeons and one orthotist. It is open to patients with head deformity with a referral letter from primary care pediatricians.
Head deformity was evaluated according to the modified Argenta classification ^{(14) (link)} and anthropometric measurements (Figure 1a and b). The anthropometric measurements of the cranial vault were obtained using a craniometer and tape measure. The reliability of these evaluation methods is reported in past studies ^{(15) (link), (16) (link), (17) (link)}. According to the method proposed by Loveday et al. ^{(18) (link)}, head circumference, cranial asymmetry (CA), and cephalic index (CI) were used. CA and cranial vault asymmetry index (CVAI) describe the severity of asymmetry. We defined CA of less than 5 mm as normal skull, 5-9 mm as mild, 10-14 mm as moderate, 15-19 mm as severe, and ≥20 mm as very severe deformity. To enable a comparison with past reports, we also described CVAI, and CVAI of less than 3.5% was defined as normal, 5%-6% as mild, 7%-9% as moderate, 10%-13% as severe, and ≥14% as very severe ^{(14) (link)}. CI describes the brachycephalic or dolichocephalic tendency. CI of less than 79 was defined as dolichocephaly and greater than 94 as brachycephaly based on the Japanese standard ^{(19) (link)}.
The patients were evaluated and treated according to the algorithm (Figure 2). The criteria for helmet therapy were Argenta ≥ II. When the parents consented with the treatment, helmet therapy was initiated.
For helmet production, infant’s head was scanned using a surface scanner (OMEGA Scanner, Ohio Willow Wood Company, Ohio, USA). The helmet was designed by a single plastic surgeon (T.A.) using specialized software (OMEGA Tracer, Ohio Willow Wood Company, Ohio, USA) supervised by a senior plastic surgeon (T.K.). The helmet (Michigan Cranial Reshaping Orthosis, Danmer Products, Michigan, USA) was fabricated in the US and sent to us (Figure 1c and d) ⁽²⁰⁾ . The family was instructed to wear the helmet for 23 h a day after setting a break-in period of 7-14 days, during which the wearing time is gradually increased, and to visit the clinic after 3 to 4 weeks for adjustment. The helmet was continually used until the helmet was tight or until the parents were satisfied with the infant’s head shape. At the completion of the treatment, the patient was re-evaluated using the Argenta classification, anthropometric measurements, and surface scanner. For the time period of this study, the cost of the helmet was partially covered by our research fund, and patients paid 100,000 Japanese yens.