Postoperative Cranial Orthotic Therapy

Introduction to Cranial Remolding Programs

Cranial remolding orthoses (CROs) were first described in the treatment of deformational plagiocephaly in 1979. The underlying principle of “directed growth” is accomplished by designing the internal surface of the orthosis to maintain total contact over the prominent areas and provide void spaces over the flattened areas of the infant’s developing skull. With continued brain and skull growth, asymmetrical and disproportionate head shapes are molded towards normocephaly within the orthosis. Based on this concept of directed growth, early success with the use of CROs for the postoperative management of craniosynostosis was reported by Persing et al. (1986) after cranial vault reconstruction and Jimenez & Barone (1998) after endoscopic removal of the affected suture(s). Postoperative CROs are designed to enhance the surgical procedure with continued reshaping of the deviated skull and prevention of secondary deformity.

Currently, postoperative CROs are recommended as standard treatment and adjuncts to endoscopic ^{, ,} and some open cranial vault surgical procedures. Successful outcomes with CROs are dependent on many factors including but not limited to:

• age of the infant,

• remaining growth of brain and skull,

• affected suture(s),

• specific clinical indications and contraindications,

• modifications and design of the cranial orthosis,

• ongoing adjustments to optimize fit and function of the orthosis,

• need for consecutive CROs,

• caregiver compliance with the wearing schedule,

• potential complications,

• skills of the cranial orthotist,

• duration of the orthotic treatment program, and

• communication and collaboration of the entire medical team.

Structured clinical follow-up and precise modifications to consecutive orthoses are provided over a strategic period of time. Ultimately, successful postoperative CRO programs are provided by experienced and trained cranial orthotists working in partnership with the surgical team.

Influence of Infant Age at Time of Surgery

Endoscopic procedures may be considered for infants up to 6 months of age; however, the best outcomes are obtained prior to 3 months of age. ^{, ,} As the function of the CRO is dependent on growth, the normal patterns of brain and skull growth must be accounted for throughout the entire postoperative orthotic remolding program. Up to 12 cm of expansion in cranial circumference is experienced during the first year after birth. Specifically, infant growth patterns predict 2 cm per month during the first 3 months of age; 1 cm per month from 4 to 6 months of age; and 0.5 cm per month from 6 to 12 months of age. Surgical corrections and focused orthotic treatment programs capture critical magnitudes of growth in the early months that are unattainable at later ages. Simple mathematics dictate that a severe deformity treated at 3 months of age might reach normocephalic parameters within the subsequent 3 months, whereas the initiation of an orthotic remolding program at 8 months of age may require orthotic treatment for at least 6 to 8 months to obtain similar outcomes. Postoperative CRO programs after early endoscopic release continue until at least 12 months of age in order to establish normocephaly, to overcorrect specific skull dimensions in some cases, and/or to reduce the risk of recurrence of the deformity. ^{, , , , , ,} Consecutive orthoses may be necessary to effectively direct and manage the anticipated 6 cm or more of circumferential cranial growth while still maintaining accurate fit and effective function of the CRO. Fig. 15.1 summarizes the influence of infant age relative to the goals of each phase of the postoperative CRO program and outlines cranial growth patterns relative to the use of consecutive CROs that will be discussed at a later point.

As a community of bones, each skull plate contacts adjacent anatomical structures. CROs effect change directly to the neurocranium with indirect changes to the viscerocranium. Primary coverage areas include the frontal, temporal, sphenoid, parietal, and occipital bones; metopic, sagittal, coronal, lambdoid, and squamous sutures; and anterior, posterior, anterolateral, and posterolateral fontanelles. The physiological function, limitations, deviations, and malformations of these anatomical structures must be considered in the orthotic design process to determine the modification strategies and guide the fitting techniques ( Fig. 15.2 ). Early surgical correction allows greater postoperative skull growth to produce a symmetrical and proportional neurocranium. Delayed treatments limit the growth opportunities that a symmetrical and proportional skull may have on facial symmetry, proportion, and overall development. The clinical rationale for early and sustained postoperative orthotic treatment programs has been well-established. ^{, , ,}

Postoperative CRO Indications/Recommendations

There is an abundance of medical literature to support the use of CROs after endoscopic release to maintain and improve the surgical correction, direct continued skull shape improvements over time, and also prevent secondary deformities. Many authors report the use of postoperative CROs as a critical component to the endoscopic surgical approach. ^{, , , , ,} Postoperative CROs are used less frequently in cases of cranial vault reconstruction surgeries when the surgical procedure itself is used to remodel the overall shape of the skull. CROs are considered in these cases for severe involvements and also to address the deformities developed from external forces.

Initial improvement in the overall shape of the skull may occur immediately after endoscopic procedures as a result of releasing the fused suture, particularly in sagittal cases. CROs serve to capture and maintain the initial surgical correction, and then continue to direct improvements in symmetry, proportion, and overall shape towards normocephaly. Most CROs are scanned, fabricated, and fitted within 7 to 10 days of surgery, allowing for some dissipation of the subgaleal swelling to ensure an optimal initial fit and function of the orthosis. ^{, , , , , , , ,} The cranial orthotist and craniofacial team must collaborate on all aspects of the postoperative care programs, while also reinforcing and supporting the caregivers’ commitment to postoperative treatment strategies.

CRO Contraindications

The medical literature lacks professional consensus regarding the optimal indications, timing, and procedures for endoscopic release. Similar concerns may also be applied to the postoperative orthotic treatment program. CROs vary in design, materials, manufacturing, clinical techniques, fit, function, and, ultimately, clinical outcomes. Requirements for a successful orthotic treatment program include a skilled and experienced cranial orthotist with specialized training in postoperative cranial remolding programs. The family must be committed to consistent clinical follow-up for strategic adjustments to the orthosis over an extended course of treatment. CRO remolding programs for postoperative cases rely on brain and skull growth and are therefore most effective when orthotic programs are completed within the first 12 months after birth. Without these key components, the success of endoscopic approaches will be limited, and other surgical procedures might be considered.

Postoperative CRO Program

An experienced cranial orthotist is a critical member of the craniofacial team. ^{, , , ,} Regular communication between the cranial orthotist and surgical team is necessary ^, as many private orthotic clinics operate outside of hospital communities. Cranial clinicians pursue advanced education for both deformational and postoperative cranial remolding concepts and utilize innovative scanning devices along with a variety of Food and Drug Administration (FDA)-cleared orthotic designs. These orthotic specialists should be provided with necessary surgical details (e.g., strip craniectomy, wedge osteotomies or barrel staves, cranial springs, etc.) to conceptualize the flexibility of the infant’s skull after surgery to enhance orthosis-directed growth opportunities. Individual patient presentations, surgical procedures, and surgeon preferences will impact the modifications to the head model, orthotic material and design selections, initial and ongoing corrections anticipated, and overall orthotic treatment objectives. Processing of infant head model and clinical specifications prior to fabrication of postoperative CROs need to be carefully planned and executed ( Fig. 15.3 ). Many cranial orthotists offer preoperative evaluations, family education, anthropometric measurements, scanning procedures, and detailed reports for the craniofacial team. Preoperative visits serve to increase the family’s understanding of the overall orthotic treatment program, as well as the importance of the specific daily tasks needed to maintain proper hygiene of the orthosis for their infant. Families will be returning to the cranial orthotist for structured follow-up, anthropometric measurements, modifications to the CRO, additional scanning procedures, continued education about the orthosis, and general support to successfully complete the treatment program with optimal results. Surgical teams should expect timely reports on head shape changes ( Fig. 15.4 ) as the collective attention to the orthotic treatment processes by the entire team reduces the need for additional corrective procedures. Postoperative orthotic protocols and guidelines should be developed to address specific patient profiles, surgical procedures, medical team protocols, orthotic scanning and fitting routines, orthotic design features, and clinical follow-up schedules that best support the needs of the craniofacial team. As an example, Fig. 15.4 shows the preoperative scan and anthropometric measurements which are compared to the 4- and 9-months postoperative scans and reflect a persistent change in the cephalic ratio.

CRO Design Specifications

Postoperative CROs are specific-to-patient, class II medical devices requiring 510(k) submission and FDA clearance to ensure safety and efficacy of this time-sensitive medical treatment program. Just as surgical techniques vary relative to suture involvement, design features of postoperative CROs are specific to the suture involvement and clinical techniques identified by the medical team. ^{, , ,} CROs are labor-intensive orthopedic devices that must be specifically and individually fitted to each child within a few days after the postoperative scanning procedures. One of the primary advantages of a CRO is the ability to continuously mold the head in both linear and volumetric dimensions. This is accomplished by a thorough evaluation of the initial head shape, understanding of surgical procedures, planned growth strategies, model rectification specifications, product and design selections, and timely fitting of the orthosis after surgery.

Scanning Procedures

Cranial clinicians now have access to a variety of portable and stationary scanners that utilize eye-safe lasers, photographs, videography, and other methods to capture an accurate digital image of the infant’s head ( Fig. 15.5 ). Scans are often acquired preoperatively (for family education and end of treatment outcome comparisons), immediately after surgery (to document surgical correction and use for fabrication), and then throughout the course of the orthotic treatment program to track efficacy of the orthotic strategy. ^{, ,} Scanning sessions are often supplemented with manual measurements by various clinical team members to confirm appropriately directed growth, although it is important to keep in mind that manual and scanner measurements will vary slightly depending upon the clinical technique and measurement tools used ( Fig. 15.6 ). All scanning technologies used for CROs must also pass safety and accuracy standards as part of the FDA 510(k) submission and clearance process.

Postoperative Orthotic Designs

Postoperative orthotic design considerations, features, and specifications have continued to evolve since their introduction in the 1980s. Once the affected suture is removed, postoperative CROs function similarly to those designed for deformational skull involvements in that they resist and promote skull growth in deliberate directions. Many initial postoperative designs are made of a clear plastic material, such as Surlyn, to allow visual inspection of the suture sites as well as direct viewing of the contact and void areas within the orthosis. Foam padding is added specific to suture involvement to create a firm initial resistance to prominent areas and guide the continued growth of the postoperative head shape. Design considerations for various head shapes may also include ease of donning and doffing by caregivers, corrective pressures with pads or strapping configurations, stability and purchase on the head to resist rotation and tipping, maintenance of a hygienic environment, ventilation holes for improved air flow, and other factors unique to the infant, surgical procedure, and care/caregiver environments ( Figs. 15.7 ).

Trim Lines

CRO trim lines are very important to capture specific areas of the neurocranium to guide growth and to assist in stabilizing the orthosis on the child’s head. Basic trim lines and contours of the CRO extend anteriorly to the eyebrows, posteriorly into the suboccipital region, laterally over the temporal bone, and distally under the mastoid areas. The ear openings must not impinge on the ears; the temporal extensions must not limit peripheral vision; and the suboccipital region must not discourage neck extension, lateral tilt or rotation. Trim line variations are common and may occur specific to the surgical procedure, at the request of the surgeon, and/or based upon the clinical strategies of the cranial orthotist. In some cases, trim lines may be left slightly longer to account for anticipated growth and to extend the use of the orthosis for as long as possible ( Fig. 15.8 ).

Side-Opening, Bivalve and Living Hinge Designs

Side-opening, bivalve (i.e., clamshell), and living hinge designs ( Fig. 15.9 ) are recommended based upon the specific skull deformity. ^, Side-opening designs are often used for coronal and lambdoid suture involvements to address frontal and parietal deformations, as well as overall symmetry and proportion. The proximal openings in side-opening band designs may vary in size, shape, and location to further address unique head shape anomalies. Bivalve and living hinge designs are often recommended for sagittal and metopic suture releases to specifically resist growth in the anterior-posterior dimension while promoting lateral expansion in the temporal and parietal regions. Bivalve and living hinge designs are also recommended to maintain contact over the open sagittal suture and when the surgeon prefers total contact over the proximal parietal regions.

Materials

Materials used in postoperative CRO designs are detailed in the 510(k) applications submitted to obtain FDA clearance for manufacturing and marketing of the orthoses. Some CRO designs are foam-lined with up to ½-inch inner foam liner to allow for strategic removal of material over time to direct and accommodate substantial three-dimensional head growth. The foam lining may be made up of single or multiple layers, and the outer shell is often a copolymer or similar thermoplastic that is either draped or bubble/blister formed over the modified head shape. The cranial orthotist will enhance the fit and function of the orthosis over time with the addition or removal of the foam lining. Reston foam is commonly used to provide initial stabilization of the orthosis, resist tipping and rotation, and compress easily with rapid cranial growth. Unlined CROs are often fabricated with Surlyn (or similar) thermoplastic materials. ^{, ,} Smaller pads are added relative to the specific suture involvement and a relatively large portion of the orthosis remains unlined. Examples of various padding configurations for common sutural involvements are shown in Fig. 15.10 . These configurations provide a starting point for the skull remolding process, and the cranial orthotist continues to modify the fit with the strategic addition and/or removal of the foam material over time. Considerable modifications are available with skilled heating and stretching of the Surlyn headband. Orthotists and surgeons often prefer Surlyn designs for the initial postoperative orthosis and may transition to a foam lined CRO for consecutive designs in order to extend the use of each orthosis over a longer period of time. These recommendations are discussed by the medical team based upon the individual patient and family needs. Continued advancements in three-dimensional printing capabilities may soon bring new design options for postoperative treatment programs in the United States pending 510(k) submission and FDA clearance.