September 2005 • Vol. 1, No. 3
	Advancing Orthotic and Prosthetic Care Through Knowledge

Case Study: The "Skull Molding Cap" and Postoperative Treatment of Metopic Craniosynostosis

by Phill Stevens, CO, LO

ABSTRACT

This case study demonstrates the use of cranial remolding orthoses as an adjunct to surgery in the treatment of a patient with metopic craniosynostosis. Concurrent with the evolution and development of cranial remolding orthoses in the treatment of positional plagiocephaly, reports were published outlining the use of "skull molding caps" as an adjunct to corrective surgery in the management of craniosynostosis. The rationale behind the use of such caps was to encourage further corrective growth and prevent relapse of the skull into its pre-surgical morphology. Significant overlap exists in the principles employed by these "molding caps" and the more frequently utilized cranial remolding orthoses that are employed in the treatment of positional plagiocephaly. A seven-month-old infant with a primary diagnosis of metopic synostosis underwent cranial vault reconstructive surgery. Following the surgery, the pediatric plastic surgeon prescribed a cranial remolding orthosis to protect the remodeled skull, prevent recurrence of the deformity and encourage further corrective shaping. Improvements in cephalic index were noted during the interval immediately following surgery and at the cessation of helmet use five months later.

BACKGROUND

Craniosynostoses are a collection of defined cranial deformities resulting from premature closure of one or more cranial sutures. In 1892, Lannelongue preformed the first attempt at surgical correction of a sagittal synostosis.¹ Since that time, "a myriad of surgical procedures have been developed and used for the treatment of this condition."² As recently as 2000, the technique of choice in many craniofacial centers was identi- fied as calvarial vault remodeling.³ In addition to the surgical corrective procedures, a few reports were published in the 1980s describing the postoperative use of "skull molding caps" (SMC) as an adjunctive treatment modality.^4-6 These devices were fabricated by occupational therapists out of low temperature plastics three–ten days following the surgery and worn throughout the day for three–six months postoperatively.^5,6 In addition to the provision of postoperative protection of the remodeled skull, SMCs were indicated to encourage further corrective growth in cases where operative procedures failed to provide complete cranial symmetry, to prevent relapse of the skull into its pre-surgical morphology and to prevent the formation of new aberrant head shapes.⁶ This was done through the application of gentle pressure in targeted regions to inhibit bone growth and the inclusion of targeted voids to promote growth in other areas.⁴

During the same time period, Clarren first described the phenomenon of "positional plagiocephaly" and its successful treatment with remolding "helmets."^7-8 These helmets rely on the same treatment principles utilized with SMCs. Concurrent with the dramatic rise in positional plagiocephaly associated with the SIDS-related "back to sleep" campaign, there has been renewed interest in cranial remolding orthoses as part of the nonoperative treatment of "positional" or "non-synostotic" plagiocephaly.^9-10

The use of orthotic molding techniques as an adjunctive treatment to traditional calvarial vault remodeling procedures is confined in recent literature to a single article reporting the effectiveness of postoperative "molding helmets" as an adjunct to surgery in the treatment of sagittal synostosis.¹¹ We present a single case of metopic synostosis and the post-surgical, adjunctive use of a cranial remolding orthosis.

CASE STUDY

The head shape associated with metopic synostosis and the observed rules that govern its development are well defined.¹² The resultant head shape of trigocephaly and its mechanism of development are illustrated in Fig 1. Because of the premature fusion of the metopic suture, the two frontal plates act as asingle plate with decreased growth potential. There is symmetrical compensatory growth on both sides of the parallel sagittal suture into the parietal plates. Finally, the compensatory growth at the perpendicular coronal sutures occurs distally, at the parietal plates, rather than the fused frontal bones.¹³ The resultant cranial morphology has been accurately described as a "biparietal pear shape."¹²

The patient underwent surgical cranial vault remodeling at age seven months and one week. While the frontal narrowing demonstrated marked improvement, there was residual biparietal bossing as seen in Fig 2. The degree of this persistent deformity was evident in the patient’s postoperative cephalic index. A standard ratio of cranial width/cranial depth, the patient’s postoperative index was 104 percent. The average value for a female between six and twelve months of age is 78.5 percent, and two standard deviations above that value is 87.5 percent.

One month after the surgery, the patient was successfully fitted with a cranial remolding orthosis. Care was taken to maintain an intimate fit over the parietal area bilaterally and at the apex of the frontal narrowing. Appropriate voids were provided lateral to the frontal apex bilaterally and in the occipital region. The orthotic objective was to restrict cranial growth in the ML dimension while encouraging an increase in cranial depth.

Over the ensuing five months, the patient realized 15 mm of circumferential cranial growth. Upon discontinuation, the patient’s measured cranial width had decreased from 146 mm to 141 mm. Cranial depth increased from 140 mm to 153 mm. These changes resulted in a post-helmet cephalic index of 92 percent. The patient’s post-helmet cranial shape is shown in Fig 3.

DISCUSSION

Orthotic assisted cranial remolding was posited by Clarren in the treatment of positional or non-synostotic cranial remolding.^7-8 Similar treatment principles were independently described by Persing and others in the postoperative treatment of craniosynostosis.^4-6 As orthotic cranial remolding techniques become more frequently utilized, their role as an adjunctive treatment in patients with craniosynostosis will require further scrutiny. Jimenez et al. have strongly advocated the use of remolding orthoses as an adjunctive treatment modality when performing less invasive endoscopic-assisted surgical procedures across the various simple synostoses.^2,3 Seymour-Dempsey et al., in their study of postoperative orthoses in the treatment of sagittal synostoses, found that, while the greatest changes in head shape were due to the surgical procedures themselves, the helmet therapy helped maintain operative corrections and produced "some additional correction."¹¹ Our practice is routinely called upon to provide postoperative helmets to patients following calvarial vault remodeling procedures. While their protective qualities are unquestioned, their ability to facilitate greater correction and possibly enhance cranial symmetry requires continued investigation. This paper describes a single case of postoperative orthotic remolding techniques in a patient who had undergone calvarial vault remodeling surgery secondary to metopic synostosis. Considerable improvements in the patient’s cephalic index were observed during five months of postoperative remolding.

REFERENCES

1. Lannelongue M. De la craniectomies dans la microcephalie. Compt Rend Seances Acad Sci. 1890;50:1382-1385.

2. Jimenez DF, Barone CM, Cartwright CC and Baker L. Early management of craniosynostosis using endoscopic-assisted strip craniectomies and cranial orthotic molding therapy. Pediatrics 2002:110(1):97-104.

3. Jimenez DF, Barone CM. Endoscopy-assisted wide-vertex craniectomy, "barrel-stave" osteotomies, and postoperative helmet molding therapy in the early management of sagittal suture craniosynostosis. Neurosurg Focus 2000;9(3):1-6.

4. Ham CK. Skull Molding Caps: External Splinting to Correct Cranial Vault Deformities. In Persing JA, et al. (eds) Scientific Foundations to Surgical Treatment of Craniosynostosis, 1989:270-274.

5. Ham CK, Meyer SW. Skull molding caps: An adjunct to craniosynostosis surgery. Plast Reconstruct Surg 1987; 80(5):737-741.

6. Persing et al. External cranial vault molding after craniofacial surgery. Ann Plast Surgery 1986;1(4):274-283.

7. Clarren SK, Smith DW and Hanson JW. Helmet treatment for plagiocephaly and congenital muscular torticollis. J Pediatrics 1979;94(1):43-46.

8. Clarren SK. Plagiocephaly and torticollis: Etiology, natural history, and helmet treatment. J Pediatrics 1981;98(1):92-95.

9. Kane AA, Mitchell LE, Craven KP and Marsh JL. Observations on a recent increase in plagiocephaly without synostosis. Pediatrics 1996;97(6):877-885.

10. Ripley CE, Pomatto J, Beals SP, et al. Treatment of positional plagiocephaly with dynamic orthotic cranioplasty. J Craniofac Surg 1994;5:150-159.

11. Seymour-Dempsey K, Baumgartner JE, Teichgraeber JF, Xia JJ, Waller AL and Gateno J. Molding helmet therapy in the management of sagittal synostosis. J Craniofac Surg 2002;13(5):631-635.

12. Delashaw JB, Persing JA, Broaddus WC, Jane JA. Cranial vault growth in craniosynostosis. J Neurosurg 1989;70:159-165.

13. Jane JA, Kant KY, Jane JA. Sagittal synostosis. Neurosurg Focus 2000;9(3):1-6.

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