Plagiocephaly (plagios for oblique and kephale for head) is a general term used to describe cranial asymmetry solely on the basis of physical attributes of the skull, as visible to the observer. 1 Deformational plagiocephaly recently entered the public spotlight after the American Academy of Pediatrics issued a report in 1992 stating that infants should be positioned on their backs while sleeping to reduce the risk of sudden infant death syndrome. 2 Since the release of the Academy’s report, research correlating sleep position and the occurrence of cranial deformation has increased the number of patients evaluated and treated for plagiocephaly. 3,4 Intentional remodeling of cranial bones has been in practice since the seventh millennium BC, when the Egyptians created specifically desired head shapes to suit cultural mores. 5,6 Clarren et al. 7 first introduced cranial molding principles as an orthotic modality in 1979. Orthotists today continue to use these principles as an effective nonsurgical treatment of this condition. The purpose of this study was to investigate the effects of orthotic cranioplasty as a nonsurgical treatment for patients with positional plagiocephaly, and it provides statistical evidence to support the treatment’s effectiveness.
To properly manage a child with cranioscoliosis, the practitioner must first understand the pathologic onset and differential diagnosis surrounding this condition. Plagiocephaly with synostosis is a malformation of one or multiple cranial sutures that results in a premature fusion of the cranial bones. This condition is rare and requires surgical intervention for the release of the pathologic sutures. 8–10 Cranial growth restriction and subsequent flattening will occur in any lobe where suture pathology exists, whereas normal sutures will advance the cranium to create a bossed appearance. When the cranium is viewed from the vertex, a trapezoidal pattern can be seen. For example, in the case of a unilambdoidal synostosis, where one lambdoid suture is pathologically fused, this “trapezoidal” appearance is apparent as bossings in a fronto-occipital position contralateral to the flattened aspects of the skull. When the skull is viewed posteriorly, one can see a parallelogram shape in the frontal plane with marked ear disharmony (the ear ipsilateral to the affected suture is lower than the ear on the nonsynostotic side). Orthotic intervention may be used postoperatively for guidance and maintenance of the surgically separated cranial plates. Plagiocephaly without synostosis affects infants with open and otherwise nonpathologic cranial sutures. This form of cranioscoliosis is initiated by deformational forces (eg, beds, car seats, and head restraints) exerted upon an immature cranium, thereby contorting an otherwise symmetrically aligned shape. Clarren 11 has aptly classified this phenomenon as deformational plagiocephaly. Torticollis, a restrictive intrauterine environment, poor bone mineralization, prematurity, and birthing trauma have also been identified as precursors linked to the occurrence of this form of malalignment. 12–14 When patients with deformational plagiocephaly are observed from the vertex, a parallelogram-shaped cranial alignment can be seen. Classically, unilateral occipitoparietal flattening is met with ipsilateral frontal bossing and contralateral occipital bossing. Further, the ipsilateral ear appears to have “migrated” anteriorly when compared with its counterpart. When assessed posteriorly in the frontal plane, no disharmony should be noted because the ears are on the same level. Alternative manifestations of classical plagiocephaly exist and must be properly assessed by the treating practitioner before orthotic management is initiated. A brachiocephalic cranium is characterized by a complete flattening of the occiput, which produces an enlarged biparietal breadth as compared with the fronto-occipital dimension. Typically, facial asymmetry is minimal; however, appreciable biparietal prominences are a manifestation that must be effectively contained for proper realignment. Scaphocephalic craniums occur primarily by parietally directed forces and present with a marked biparietal narrowing with concurrent fronto-occipital enlargement. Physical and radiographic analysis should be used to completely rule out a suspected synostosis before orthotic management.
The managing practitioner should obtain a complete history and cranial evaluation before an orthotic protocol is initiated. Anthropometric and cross-sectional quadrangular evaluations afford the orthotist definitive insight regarding the pattern and complexity of the deformity. An impression of the child’s skull may then be obtained for the fabrication of the orthosis.
Anthropometric landmarks proposed by Kolar 15 are inscribed on the 4-inch cotton hood as reference points during the plaster application (Figure 1) An initial elastic layer of 4-inch Orthoflex and a secondary rigid layer of 4-inch Specialist (both from General Medical Corporation, Richmond, VA) are applied circumferentially over the hood, and a 1/2-inch rubber spacer tube is positioned vertically over the flattened aspect of the occiput. The cast should extend inferiorly from the cranial vertex to the inferior concavity of the occipital protuberance, 1 cm inferior to the subaurale aspect of the ear bilaterally, and terminate on the inferior aspect of the eyebrows. Once the cast has hardened, the spacer tube is removed, and the resultant opening is separated with bandage scissors. The mold removed from the patient’s head is then used as a negative model of the infant’s skull. The negative impression is filled with liquid plaster to form the positive model that will be used in the design of the orthosis. A transverse cross-sectional evaluation of the model provides accurate quantitative data regarding the patient’s asymmetry and a focused treatment plan for the orthotist. Plaster modification techniques can be used to realign the model according to the data collected by expanding the mold circumferentially 1 to 3 cm depending on the patient’s age and deformational pattern. Durr Plex (Cascade Orthopedic, Chester, CA) is then thermoformed over the realigned model to create the definitive orthosis. The clarity of Durr Plex affords the parent and practitioner immediate feedback as to the condition of the child’s skin, thus eliminating potential skin insults. Three-millimeter Nora Lunairflex (Atlas International, Sacramento, CA) perforated padding is applied to the inside inferior 2.5-cm aspect of the orthosis in degrees that correspond with the cranial depressions, providing a secure fit while minimizing planar rotation. The frontal and occipital cranial prominences will be in close contact with the shell of the orthosis, while the depressed aspects will be positioned within the realignment voids.
Optimum fit of the cranioplasty orthosis is achieved when the polymer comfortably holds the bossed areas of the child’s skull. As the child’s skull grows, these prominences will be held in equilibrium with the orthosis, and outward cranial growth will be passively kept from progressing (Figure 2). The progression of the expanding cranium during growth cycles is focused into the realignment voids, which results in a gradual resolution of the craniofacial asymmetry. The rate of cranial remodeling is dependent upon the child’s growth rate, and force exerted upon the orthosis will fluctuate in accordance with these cycles. Patients wear the orthosis for 23 hours of a 24-hour cycle, beginning with the fitting appointment. Parents are instructed to remove the helmet during the 30-minute break between cycles to perform hygienic maintenance and routine skin checks. Follow-up appointments should be scheduled with the treating orthotist at monthly intervals. During these appointments, the orthotist monitors and quantifies patient progress and makes padding adjustments to ensure a proper fit. Cross-sectional quadrangular evaluations, performed in conjunction with an anthropometric analysis, provide a valuable tool for assessing the overall progress of the patient’s realignment, in addition to immediate feedback regarding the patient’s potential for realignment, padding adjustments, and orthosis integrity.
A pilot study of this method was conducted over a 1-year period. The study group comprised 12 patients with a mean age (± SD) of 7.9 (± 2.1) months (range, 5 to 14 months). Monthly anthropometric measurements, as proposed by Farkas 16 and by Kolar and Salter, 15 and cross-sectional quadrangular data were entered into a spreadsheet for storage and analysis using Microsoft Excel (Microcenter, Fairfax, VA). These measurements, selected for their effectiveness in comparing and quantifying key craniofacial areas affected by plagiocephaly, are described in Figure 3 and Table 1. Paired t-tests were used to analyze pretreatment and posttreatment anthropometric and quadrangular values, and correction was considered significant if p < .05 (Tables 2, 3, and 4). Skull base asymmetry resolved at the slowest rate for all patients, which suggests that a kinetic chain exists that emanates from the cranial vault and progresses inferiorly through the temporozygomatic arch into the facial bones and lower mandibular region. A cross-sectional quadrangular evaluation, performed in conjunction with the anthropometric analysis, demonstrated a significant decrease in cranial quadrant asymmetry and facial disharmony.
Patients who began orthotic treatment by 6 months of age demonstrated the highest rate of symmetrical resolution. The rate of correction decreased as the child’s age increased, supporting the findings of Kelly, 17 Littlefield, 18 and Ripley, 19 who correlated age of treatment initiation with treatment success. Our findings also support the study by Marsh and Vannier 20 indicating that spontaneous resolution does not occur after the patient is 5 months of age. A long-term, broad-based study has been initiated since the completion of this pilot study to further assess and quantify the efficacy of orthotic management for plagiocephaly.
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Keywords:© 2001 Lippincott Williams & Wilkins, Inc.
Orthotic cranioplasty; positional plagiocephaly; nonsurgical treatment; cranial asymmetry