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Posterior plagiocephaly: proactive conservative management
British Journal of Plastic Surgery (1999), 52, 18–23 © 1999 The British Association of Plastic Surgeons
Posterior plagiocephaly: proactive conservative management E. S. O’Broin, D. Allcutt and M. J. Earley Temple Street Craniofacial Unit, The Children’s Hospital, Temple Street, Dublin, Republic of Ireland SUMMARY. The pathology, diagnosis and management of posterior plagiocephaly remains highly controversial. While the rationale for surgical management of true lambdoid synostosis is undisputed, opinions vary greatly on how to manage severe, unresolving, non-synostotic cases. We reviewed 39 cases of posterior plagiocephaly, 37 of which were treated conservatively. Of these, 34 patients had a significant improvement over the following year with sleep posture modification and/or physiotherapy. While only eight cases returned to complete normality, the remainder had deformities that were deemed mild by both mothers and surgeons, and did not merit surgery. Defining recalcitrant cases remains elusive as standard imaging is often unhelpful. While 3-D CT offers a much more accurate diagnosis of true lambdoid synostosis with bony union and allows objective assessment of the deformity, serial scans involve radiation doses that are difficult to justify. Clinical follow-up is the only reliable method at present. Keywords: posterior plagiocephaly, lambdoid synostosis, non-synostotic plagiocephaly.
lambdoid sutures are a secondary result of deformational forces.1,8,9 These forces may be exerted in utero, but in addition can occur later due to a habitual lying position, hence the term positional plagiocephaly.1,2 These fundamental differences in the nomenclature and classification lead to differences in diagnosis and management, as clinicians who maintain that the lambdoid suture is functionally synostosed have a lower threshold for operative intervention. For example, the incidence of lambdoid synostosis as a percentage of all synostoses (most requiring surgery) was reported by some authors as 15–21%6,10,11 which is in stark contrast to 3.1% as reported more recently by Huang et al.4 True lambdoid synostosis, while very uncommon, often creates a severe progressive deformity and surgical correction is usually deemed necessary even in conservative units.4 However, moderate or severe ‘nonsynostotic plagiocephaly’ not improving or becoming worse with conservative measures may create a diagnostic and management dilemma. These borderline cases are the source of most disagreement on this topic. Recent publications have attempted to define and distinguish between synostotic and non-synostotic cases based on clinical,4 X-ray12 or CT findings.13 There also appears to be a trend away from operative management of such borderline cases.5,14 In keeping with these trends, the Craniofacial Unit in Dublin has adopted a conservative approach to this condition and we therefore wished to review this management strategy. The aims of this paper are first to analyse patient data of 39 new posterior plagiocephaly cases from a 1-year period (1995), in particular looking at possible aetiological and associated factors. The second aim is to assess the progress of these patients as objectively as possible. The final aim is to review possible
Plagiocephaly, meaning asymmetrical head, is a term which includes conditions with different pathologies, outcomes and management. The controversies surrounding this topic are compounded by inconsistencies in nomenclature and hence classification. The three main pathological subgroups of plagiocephaly are unilateral coronal synostosis, unilateral lambdoid synostosis and ‘non-synostotic plagiocephaly’. Some authors use the term frontal plagiocephaly to cover all three variants as they may all produce a forehead deformity.1–3 Others classify unilateral coronal synostosis separately as frontal plagiocephaly and place lambdoid synostosis and ‘non-synostotic plagiocephaly’ in the category posterior plagiocephaly.4,5 The entity which causes the most confusion, though, is the subgroup ‘non-synostotic plagiocephaly’. Most clinicians fall into one of two camps regarding their classification and understanding of this subgroup. McComb and Cohen refer to it as functional synostosis, maintaining that histological features of lambdoid sutures in these cases, such as cartilaginous changes, increased bony ridging and interdigitation, are evidence of a primary sutural abnormality.6,7 This leads to abnormal membranous bone development at these sutures, which effectively behave like synostosed sutures (true synostosis with bony bridging being rare, occurring only in 7% of histological cases examined by Cohen). The alternative viewpoint makes a very clear distinction between the rare, true lambdoid synostosis and ‘non-synostotic plagiocephaly’. Advocates of this viewpoint label the non-synostotic variety ‘deformational plagiocephaly’, claiming that the histological changes observed in these Presented at Summer British Association of Plastic Surgeons meeting, 3 July 1997, Latimer House, Chesham, Buckinghamshire, UK.
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Posterior plagiocephaly: proactive conservative management
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Table 1 Thirty-nine new posterior plagiocephaly cases seen in 1995 Flat side
Dxtime
MED/PREG/FM Hx
1 2 3 4 5 6* 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26* 27 28 29 30 31 32 33 34 35 36 37 38 39
1/52 1/52 1/52 1/52 1/52 1/52 1/52 1/52 1/52 2/52 4/12 3/12 4/12 3/12 6/52 2/12 3/12 10/12 4/12 4/12 6/52 3/12 2/12 4/12 3/12 6/52 3/12 4/12 1/12 1/12 3/12 3/12 12/12 2/12 14/12 4/12 3/12 4/12 3/12
Sib with condition
R R R R R L L L L R R R R R R R R R R R R R R R R R R R L L L L L L L Bilat L L L
DL
Hydrocephalus, VSD
f
Hirschprungs Normal twin Sibling with condition
f
Sleep posit Both Both R ? Both R Both L Both ? R R L? Both R Both R Both ? ? R R R R R R ? R L R L L Both L L ? L ? L
Cleft palate c Developmental delay Hydrocephalus Developmental delay Hypospadias Cleft palate Transverse lie
L amelia, R phoc Premature c Aborted twin, hydroceph Polyhydramnios Uncle with condition Slow to sit Normal twin VSD
c f
TORT
t,s
t t t
t t
t t
SCORE 1 & 2 2, 1 4, 2 4, 2 – 3, 1 5, 2 4, 2 3, 1 3, 3 2, 2 2.5, 1.5 3, 2 3, 1.5 5, 4 3, 1 3, 2 2, 1.5 3, 3 – – 2.5, 2 2, 1.5 2, 1 3, 2 3.5, 1.5 3.5, 1.5 – 3, 1 3, 1.5 3, 1.5 4, 2 3, 2 2.5, 1.5 3, 2 3, 2 – 4, 1 – 3, 1
Abbreviations used in Table 1: Dxtime, age of baby at first referral; MED/PREG/FM Hx, medical, pregnancy or family history of relevance; DL, type of delivery (blank, normal vaginal; c, caesarean; f, forceps); Sleep posit, habitual lying position (R, right; L, left); TORT (t, torticollis; s, strabismus); SCORE 1 & 2, parental perception of severity scores 1 at first visit and 2 at most recent visit. *Marks operative cases.
techniques for more objective assessment of this condition. Materials and methods Thirty-nine children (26 males) with a previous diagnosis of posterior plagiocephaly were chart reviewed. Data were obtained from their history and findings at physical examination taken at their first and most recent outpatients visit. All chart details were documented by the senior author in a consistent format (Table 1). Patients had head circumference measurements, standardised photographs and plain skull X-rays at their first appointment. Four patients had CT scans including two 3-D CT reconstructions to rule out other intracranial pathology and to aid surgery (two cases). We attempted to scan some of the patients with a 3-D surface scanner, but abandoned this procedure as hair interfered with the scan and it was deemed unhelpful. Patients in this study were observed on an ongoing basis for a minimum of 1 year (mean 18.2 months at
commencement of study) with the exception of two patients whose deformities continued to worsen and required corrective surgery. All other patients had sleep position correction and physiotherapy if necessary. Cases with torticollis had intensive physiotherapy and three of these also had surgical release of the sternocleidomastoid muscle. Finally, the parents of the children were sent a questionnaire checking data already obtained from the charts and also requesting them to mark on an analogue scale their perception of the severity of their child’s deformity. They were asked to score the severity of the deformity (1–5) as they perceived it when the patient was first referred to the clinic, and also to score the deformity as they perceived it over 1 year later. The response rate was 84.6% (33 completed questionnaires). Results The mean age at first review was 3.2 months and the mean age at the time of most recent review was 18.2
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British Journal of Plastic Surgery
Figure 2—Occipito-frontal view highlighting normal sutures. Figure 1—Occipito-frontal view showing asymmetry of skull.
months. The majority of deliveries were normal vaginal, but three were forceps assisted and three caesareans. There were 30 cases with some degree of plagiocephaly at birth, but most were thought to be moulding and only 10 were referred to the Craniofacial Unit as neonates; of these, there were two forceps-assisted deliveries, one twin, one case of mild hydrocephalus and two siblings. Their parents were advised to keep the babies lying on the unflattened side of their occiputs. The remaining 29 patients presented at a mean age of 4.3 months and of these, 19 habitually lay on the flat side, one lay on the opposite side according to the parents (although we would question this), four did not lie on a particular side and the preferred lying position was unknown in five cases. The deformity occurred on the right side in 24 cases and 14 cases had left occipital plagiocephaly, including three twins. One patient had bilateral occipital flattening. On review of other aetiological and associated factors there were eight cases with torticollis and one with strabismus. Five babies were slow to sit up due to hypotonia and developmental delay (4) and phocomelia (1). Three patients had mild hydrocephalus (one required a temporary ventriculo-peritoneal shunt). Indications of intrauterine aetiology were found in five cases (one polyhydramnios, one transverse lie, three twins but only one was diagnosed occipital plagiocephaly at birth). There were two cases of suspected lambdoid synostosis with a severe worsening deformity. Both had posterior cranioplasties with satisfactory results. With the exception of the cases with mild hydrocephalus, head circumferences were within normal ranges at all visits for all patients. Photographs were very difficult to standardise and were not a useful objective assessment of the deformity. X-ray findings were difficult to interpret (Figs 1, 2) and showed a degree of sclerosis and petrous bone deformity in the operative cases, but no definite fused
suture was seen nor was synostosis of the asterion noted on review of any of the plain films. No comment could be made on the severity of the deformity or on its progression on serial X-rays. Three-dimensional CT was useful in cases undergoing surgery, but the radiation dose and the anaesthetic were deemed unnecessary for most patients. Surface scanning using a colour light striping technique with computer 3-D reconstruction was not useful, as landmarks and features were masked by hair. Parents scored their impression of the severity of the deformity when first diagnosed and at the time of the study on a simple 1–5 scale (1 = normal, 2 = mild deformity, 3 = obvious deformity, 4 = severe deformity, 5 = very severe deformity).15 Thirty-three questionnaires were returned. The mean improvements over time were scored by the parents as shown in Figure 3. A Student t-test showed a significant difference between scores at diagnosis and after 1 year (P = 0.05), indicating a definite improvement, but complete resolution did not occur in most cases. There was no statistically significant difference between early and late diagnosis groups (Fig. 3A). There was a trend towards increasing severity in cases with torticollis both at diagnosis and after 1 year but while not surprising, this was not statistically significant (Fig. 3B). Discussion The Temple Street Craniofacial Unit serves a population of approximately three million; the estimated incidence is therefore 1/75,000. This is probably a significant underestimate, as many mild cases are not referred and an incidence as high as 1/300 has been reported.16 Neonatal moulding caused by compression forces during labour may account for some of these, but there is little doubt that this is an underdiagnosed condition. Moulding occurs in up to 48% of neonates,
Posterior plagiocephaly: proactive conservative management 5 4.5 4 3.5 3 Y 2.5 2 1.5 1 0.5 0
Early diagnosis n=9 Later diagnosis n = 24
At diagnosis
After one year
Figure 3A—Improvement in perception of severity scores with time showing early and late referral cases separately.
Figure 4—Diagram of foetal head in left occipito-anterior position in pelvis: growth constraint occurs in right occiput.
leading to mild temporary cranial deformities which resolve within 6 weeks.1,2 The incidence of plagiocephaly has risen in countries adopting paediatricians’ recommendations promoting the supine sleeping position in order to reduce the risk of SIDS.17–19 It is also interesting that 18 out of 24 patients diagnosed after 2 months habitually slept on the flattened side of the occiput. This is in keeping with an 80% correlation found by Argenta et al.17 Five of these patients were slow to gain head control and eight had the classical association with torticollis, which also forces the baby to lie on one side and may also apply direct deformational forces to the occiput. In keeping with many other studies there is a predominance of right-sided plagiocephaly (23:15). These data support the theory that external deformational force is the most significant factor leading to posterior non-synostotic plagiocephaly. The problem may start in utero as 85% of vertex presentations lie in the left occipital anterior position in the pelvis which may constrain growth in the R occipital and L frontal regions if early pelvic descent occurs (Fig. 4).1,2 This growth constraint is further perpetuated if the infant preferentially lies on the flattened side. Additional evidence supporting this hypothesis includes the fact that the condition is more common in multiple pregnancies, with abnormal foetal lie and uterine abnormalities, although our figures are too small to demonstrate a definite relationship.2 It has been reported that the
21 5 4.5 4 3.5 3 Y 2.5 2 1.5 1 0.5 0
With torticollis n=7 Without torticollis n = 26
At diagnosis
After one year
Figure 3B––Improvement in severity score in patients with and without torticollis.
Figure 5—Illustrations with superior and posterior views showing main clinical differences between true lambdoid synostosis (left) and deformational plagiocephaly (right).
length of time required to produce a lasting deformation of the cranium is several weeks to 3 months.20 For years, the distinction between deformational plagiocephaly and lambdoid synostosis was based not on differences in skull pattern, but rather on evidence of progression of deformity.4 Non-synostotic plagiocephaly gives rise to a rhomboid-shaped cranium when observed from above. There is occipital flattening, contralateral bossing and ipsilateral forehead bossing producing a parallelogram or rhomboid shape. In addition there is anterior displacement and prominence of the ipsilateral ear, but little tilt of the skull base,4 as shown on the right set of diagrams in Figure 5. According to some authors, in more severe cases the ipsilateral malar eminence also projects with the forehead.1,2,17 Patients with true lambdoid synostosis, shown on the left in Figure 5, also have a flattened occiput, but in addition have contralateral parietal bossing and contralateral frontal bossing giving rise to a trapeziumshaped head.4 The ipsilateral ear is displaced inferiorly and posteriorly and the skull base is tilted likewise. In cases of true lambdoid synostosis, there will also be external ridging of the fused suture as is found in other craniosynostoses. While the patients should be photographed for documentation purposes, we found this modality very
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British Journal of Plastic Surgery
Figure 6—Three-dimensional CT scan of posterior skull showing asymmetry but normal lambdoid suture.
Figure 7—Three-dimensional CT scan, lateral view, showing asymmetry but normal lambdoid suture and asterion.
limited in objective assessment of the deformity. To get standardised views without a cephalostat is difficult and, in our experience, the deformity does not project very well in a 2-D format. Plain skull X-rays may show obliteration of the lambdoid suture, but the sign most frequently referred to is bone sclerosis adjacent to the suture.10 We would question the validity of this sign, as sclerosis may be secondary to deformational forces and therefore not an indication of synostosis, functional or otherwise. In severe and especially bilateral cases there may be copper beating of the posterior cranial fossa, although this is unusual. The petrous bone may also be deformed in more severe cases, with depression of the petrous ridge and semicircular canals seen on Towne projection.12 In our experience, most of these signs can be vague and may not be helpful in borderline cases (Figs 1, 2). Asterion synostosis is another X-ray finding based on a new theory that many borderline cases may not have lambdoid synostosis, but have an isolated area of fusion in the asterion (junction of parietal, occipital and temporal bones).11 This area can be difficult to see on plain film and may need 3-D CT to obtain clear views (Figs 6, 7). We report no cases in this series with this finding. Technecium radionucleotide bone scanning may show increased activity during the active phase of bony union, but will show decreased activity once union has occurred. The suture’s activity can be compared with its contralateral partner bearing in mind that it has been demonstrated that the lambdoid suture is at its most active in a 3month-old baby. Proponents of this technique claim that this investigation can be very helpful, but it is questionable whether the radiation dose involved is acceptable in most cases.10 Both CT and 3-D CT (Figs 6, 7) demonstrate the deformity in a qualitative fashion and until recently were not very helpful in distinguishing subtypes of plagiocephaly. It has been found that even experienced neuro-radiologists were inconsistent in distinguishing between lambdoid synostosis and deformational plagiocephaly.13 A useful objective method of distin-
guishing between these two entities has been described, which is based on the angles between the central axis of the anterior and the posterior cranial fossae with a bird’s-eye view of the endocranial base on 3-D CT scans.13 Unfortunately a useful tool for quantitative assessment of progress of the condition has not been described. While it is feasible to take standardised CT cuts at a set level above and parallel to the Frankfort plane and with specialised software to obtain volume/symmetry indices from 3-D CT reconstructions, these methods of follow-up would require multiple CT scans and significant radiation exposure. We consider the radiation dose and the necessary paediatric general anaesthetic unjustified even for a single scan, unless surgery is being seriously considered. Another possibility is the use of 3-D MRI scans, but this is also expensive, involves highly specialised software and requires a general anaesthetic. Our unit has access to a 3-D surface scanner which was proposed as an alternative to CT for objective follow-up, but this technique, using either a laser or a collimated light source is unhelpful, as hair on the back of the head disperses light. Our results show that while nearly all patients improve with conservative treatment, most retain mild deformity and it is unlikely that this will resolve as the child grows.20 We therefore feel that changing the babies’ sleep positions alone may not be the optimal treatment. Helmet treatment was first described by Clarren et al in 1979,21 but has only recently gained popularity and it is possible that even some severe non-synostotic cases may respond to this therapy. It requires a specialised technician, as all helmets must be custom designed for the needs of the patient. It is also important that this treatment is instituted early, as it is ineffective if started after the age of 6 months.22 The effectiveness of this technique when compared with repositioning alone has not been established in any controlled series.19 Finally, it is agreed by most that there is a small subgroup of patients who have severe progressive positional deformities who require surgical
Posterior plagiocephaly: proactive conservative management
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intervention, as was the case for two patients in this study group who required posterior cranioplasty.23
11. Jimenez DF, Barone CM, Argamaso RV, Goodrich JT, Shprintzen RJ. Asterion region synostosis. Cleft Palate Craniofac J 1994; 31: 136–41. 12. Fernbach SK, Feinstein KA. The deformed petrous bone: a new plain film sign of premature lambdoid synostosis. Am J Roentgenol 1991; 156: 1215–17. 13. Lo L-J, Marsh JL, Pilgram TK, Vannier MW. Plagiocephaly: differential diagnosis based on endocranial morphology. Plast Reconstr Surg 1996; 97: 282–91. 14. McComb JG. The sunrise technique: the correction of occipital plagiocephaly using bandeau occipital plate and radial osteotomies (discussion). Pediatr Neurosurg 1995; 22: 166. 15. Vander Kolk CA, Carson BS. Lambdoid synostosis. Clin Plast Surg 1994; 21: 575–84. 16. Dunn PM. Congenital postural deformities. Br Med Bull 1976; 32: 71–6. 17. Argenta LC, David LR, Wilson JA, Bell WO. An increase in infant cranial deformity with supine sleeping position. J Craniofac Surg 1996; 7: 5–11. 18. American Academy of Pediatrics (AAP) task force on infant positioning and SIDS: positioning and SIDS. Pediatrics 1992; 89: 1120–6. 19. Persing JA. The differential diagnosis of posterior plagiocephaly: true lambdoid synostosis versus positional molding (discussion). Plast Reconstr Surg 1996; 98: 775–6. 20. Ripley CE, Pomatto J, Beals SP, Joganic EF, Manwaring KH, Moss SD. Treatment of positional plagiocephaly with dynamic orthotic cranioplasty. J Craniofac Surg 1994; 5: 150–9. 21. Clarren SK. Plagiocephaly and torticollis: etiology, natural history, and helmet treatment. J Pediatrics 1981; 98: 92–5. 22. Clarren SK, Smith DW, Hanson JW. Helmet treatment for plagiocephaly and congenital muscular torticollis. J Pediatrics 1979; 94: 43–6. 23. Lin K, Opperman L, Nolen A, et al. Surgical approach to posterior skull deformities. Presented at 6th Congress of the International Society of Craniofacial Surgery, St Tropez, France, 1995.
Conclusions As the incidence of this controversial condition increases dramatically, it is necessary that craniofacial surgeons develop a better understanding of posterior plagiocephaly and come to a consensus view on its management. At present, clinical assessment and follow-up is the most reliable method for deciding whether surgery will be necessary, although CT of the endocranial base may also be helpful. There are no ideal objective techniques at present to monitor the deformity over time and this area remains a challenge. Helmet treatment may play an important role in the conservative management of these patients as simple conservative methods can sometimes be disappointing. References 1. Hansen M, Mulliken JB. Frontal plagiocephaly: diagnosis and treatment. Clin Plast Surg 1994; 21: 543–53. 2. Bruneteau RJ, Mulliken JB. Frontal plagiocephaly: synostotic, compensational, or deformational. Plast Reconstr Surg 1992; 89: 21–31. 3. Gosain AK, Steel M, McCarthy JG, et al. A prospective study of the presentation and outcome of strabismus and head posture in patients with plagiocephaly. 5th International Congress of the International Society of Craniofacial Surgery, Oaxaco, Mexico, 1993. 4. Huang MHS, Gruss JS, Clarren SK, et al. The differential diagnosis of posterior plagiocephaly: true lambdoid synostosis versus positional molding. Plast Reconstr Surg 1996; 98: 765–74. 5. David JD, Poswillo D, Simpson D. The craniosynostoses: causes, natural history and management. New York: Springer–Verlag, 1982, 23–6. 6. McComb JG. Treatment of functional lambdoid synostosis. Neurosurg Clin North America 1991; 2: 665–72. 7. Cohen MM Jr. Sutural biology and the correlates of craniosynostosis. Am J Med Gen 1993; 47: 581–616. 8. Sitsen AE. Zur entwicklung der nahte des schledeldaches. Z Anat Entwicklungsglesch 1993; 101: 121–51. 9. Hinton DR, Becker LE, Muakkassa KF, Hoffman HJ. Lambdoid synostosis: Part 1; The lambdoid suture: normal development and pathology of ‘synostosis’. J Neurosurg 1984; 61: 333–9. 10. Muakkassa KF, Hoffman HJ, Hinton DR, Hendrick EB, Humphrey RP, Ash J. Lambdoid synostosis: Part 2; Review of cases managed at the Hospital for Sick Children, 1972–1982. J Neurosurg 1984; 61: 340–7.
The Authors E. S. O’Broin, MMedSc, FRCSI, Registrar in Plastic and Reconstructive Surgery, Cork University Hospital, Wilton, Cork, Republic of Ireland. D. Allcutt, FRCS, Consultant Neurosurgeon, M. J. Earley, MCh, FRCS (Plast), Consultant in Plastic and Reconstructive Surgery, Temple Street Children’s Hospital, Dublin, Republic of Ireland. Correspondence to Mr M. J. Earley. Paper received 1 October 1997. Accepted 18 September 1998, after revision.
Posterior plagiocephaly: proactive conservative management E. S. O’Broin, D. Allcutt and M. J. Earley Temple Street Craniofacial Unit, The Children’s Hospital, Temple Street, Dublin, Republic of Ireland SUMMARY. The pathology, diagnosis and management of posterior plagiocephaly remains highly controversial. While the rationale for surgical management of true lambdoid synostosis is undisputed, opinions vary greatly on how to manage severe, unresolving, non-synostotic cases. We reviewed 39 cases of posterior plagiocephaly, 37 of which were treated conservatively. Of these, 34 patients had a significant improvement over the following year with sleep posture modification and/or physiotherapy. While only eight cases returned to complete normality, the remainder had deformities that were deemed mild by both mothers and surgeons, and did not merit surgery. Defining recalcitrant cases remains elusive as standard imaging is often unhelpful. While 3-D CT offers a much more accurate diagnosis of true lambdoid synostosis with bony union and allows objective assessment of the deformity, serial scans involve radiation doses that are difficult to justify. Clinical follow-up is the only reliable method at present. Keywords: posterior plagiocephaly, lambdoid synostosis, non-synostotic plagiocephaly.
lambdoid sutures are a secondary result of deformational forces.1,8,9 These forces may be exerted in utero, but in addition can occur later due to a habitual lying position, hence the term positional plagiocephaly.1,2 These fundamental differences in the nomenclature and classification lead to differences in diagnosis and management, as clinicians who maintain that the lambdoid suture is functionally synostosed have a lower threshold for operative intervention. For example, the incidence of lambdoid synostosis as a percentage of all synostoses (most requiring surgery) was reported by some authors as 15–21%6,10,11 which is in stark contrast to 3.1% as reported more recently by Huang et al.4 True lambdoid synostosis, while very uncommon, often creates a severe progressive deformity and surgical correction is usually deemed necessary even in conservative units.4 However, moderate or severe ‘nonsynostotic plagiocephaly’ not improving or becoming worse with conservative measures may create a diagnostic and management dilemma. These borderline cases are the source of most disagreement on this topic. Recent publications have attempted to define and distinguish between synostotic and non-synostotic cases based on clinical,4 X-ray12 or CT findings.13 There also appears to be a trend away from operative management of such borderline cases.5,14 In keeping with these trends, the Craniofacial Unit in Dublin has adopted a conservative approach to this condition and we therefore wished to review this management strategy. The aims of this paper are first to analyse patient data of 39 new posterior plagiocephaly cases from a 1-year period (1995), in particular looking at possible aetiological and associated factors. The second aim is to assess the progress of these patients as objectively as possible. The final aim is to review possible
Plagiocephaly, meaning asymmetrical head, is a term which includes conditions with different pathologies, outcomes and management. The controversies surrounding this topic are compounded by inconsistencies in nomenclature and hence classification. The three main pathological subgroups of plagiocephaly are unilateral coronal synostosis, unilateral lambdoid synostosis and ‘non-synostotic plagiocephaly’. Some authors use the term frontal plagiocephaly to cover all three variants as they may all produce a forehead deformity.1–3 Others classify unilateral coronal synostosis separately as frontal plagiocephaly and place lambdoid synostosis and ‘non-synostotic plagiocephaly’ in the category posterior plagiocephaly.4,5 The entity which causes the most confusion, though, is the subgroup ‘non-synostotic plagiocephaly’. Most clinicians fall into one of two camps regarding their classification and understanding of this subgroup. McComb and Cohen refer to it as functional synostosis, maintaining that histological features of lambdoid sutures in these cases, such as cartilaginous changes, increased bony ridging and interdigitation, are evidence of a primary sutural abnormality.6,7 This leads to abnormal membranous bone development at these sutures, which effectively behave like synostosed sutures (true synostosis with bony bridging being rare, occurring only in 7% of histological cases examined by Cohen). The alternative viewpoint makes a very clear distinction between the rare, true lambdoid synostosis and ‘non-synostotic plagiocephaly’. Advocates of this viewpoint label the non-synostotic variety ‘deformational plagiocephaly’, claiming that the histological changes observed in these Presented at Summer British Association of Plastic Surgeons meeting, 3 July 1997, Latimer House, Chesham, Buckinghamshire, UK.
18
Posterior plagiocephaly: proactive conservative management
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Table 1 Thirty-nine new posterior plagiocephaly cases seen in 1995 Flat side
Dxtime
MED/PREG/FM Hx
1 2 3 4 5 6* 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26* 27 28 29 30 31 32 33 34 35 36 37 38 39
1/52 1/52 1/52 1/52 1/52 1/52 1/52 1/52 1/52 2/52 4/12 3/12 4/12 3/12 6/52 2/12 3/12 10/12 4/12 4/12 6/52 3/12 2/12 4/12 3/12 6/52 3/12 4/12 1/12 1/12 3/12 3/12 12/12 2/12 14/12 4/12 3/12 4/12 3/12
Sib with condition
R R R R R L L L L R R R R R R R R R R R R R R R R R R R L L L L L L L Bilat L L L
DL
Hydrocephalus, VSD
f
Hirschprungs Normal twin Sibling with condition
f
Sleep posit Both Both R ? Both R Both L Both ? R R L? Both R Both R Both ? ? R R R R R R ? R L R L L Both L L ? L ? L
Cleft palate c Developmental delay Hydrocephalus Developmental delay Hypospadias Cleft palate Transverse lie
L amelia, R phoc Premature c Aborted twin, hydroceph Polyhydramnios Uncle with condition Slow to sit Normal twin VSD
c f
TORT
t,s
t t t
t t
t t
SCORE 1 & 2 2, 1 4, 2 4, 2 – 3, 1 5, 2 4, 2 3, 1 3, 3 2, 2 2.5, 1.5 3, 2 3, 1.5 5, 4 3, 1 3, 2 2, 1.5 3, 3 – – 2.5, 2 2, 1.5 2, 1 3, 2 3.5, 1.5 3.5, 1.5 – 3, 1 3, 1.5 3, 1.5 4, 2 3, 2 2.5, 1.5 3, 2 3, 2 – 4, 1 – 3, 1
Abbreviations used in Table 1: Dxtime, age of baby at first referral; MED/PREG/FM Hx, medical, pregnancy or family history of relevance; DL, type of delivery (blank, normal vaginal; c, caesarean; f, forceps); Sleep posit, habitual lying position (R, right; L, left); TORT (t, torticollis; s, strabismus); SCORE 1 & 2, parental perception of severity scores 1 at first visit and 2 at most recent visit. *Marks operative cases.
techniques for more objective assessment of this condition. Materials and methods Thirty-nine children (26 males) with a previous diagnosis of posterior plagiocephaly were chart reviewed. Data were obtained from their history and findings at physical examination taken at their first and most recent outpatients visit. All chart details were documented by the senior author in a consistent format (Table 1). Patients had head circumference measurements, standardised photographs and plain skull X-rays at their first appointment. Four patients had CT scans including two 3-D CT reconstructions to rule out other intracranial pathology and to aid surgery (two cases). We attempted to scan some of the patients with a 3-D surface scanner, but abandoned this procedure as hair interfered with the scan and it was deemed unhelpful. Patients in this study were observed on an ongoing basis for a minimum of 1 year (mean 18.2 months at
commencement of study) with the exception of two patients whose deformities continued to worsen and required corrective surgery. All other patients had sleep position correction and physiotherapy if necessary. Cases with torticollis had intensive physiotherapy and three of these also had surgical release of the sternocleidomastoid muscle. Finally, the parents of the children were sent a questionnaire checking data already obtained from the charts and also requesting them to mark on an analogue scale their perception of the severity of their child’s deformity. They were asked to score the severity of the deformity (1–5) as they perceived it when the patient was first referred to the clinic, and also to score the deformity as they perceived it over 1 year later. The response rate was 84.6% (33 completed questionnaires). Results The mean age at first review was 3.2 months and the mean age at the time of most recent review was 18.2
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Figure 2—Occipito-frontal view highlighting normal sutures. Figure 1—Occipito-frontal view showing asymmetry of skull.
months. The majority of deliveries were normal vaginal, but three were forceps assisted and three caesareans. There were 30 cases with some degree of plagiocephaly at birth, but most were thought to be moulding and only 10 were referred to the Craniofacial Unit as neonates; of these, there were two forceps-assisted deliveries, one twin, one case of mild hydrocephalus and two siblings. Their parents were advised to keep the babies lying on the unflattened side of their occiputs. The remaining 29 patients presented at a mean age of 4.3 months and of these, 19 habitually lay on the flat side, one lay on the opposite side according to the parents (although we would question this), four did not lie on a particular side and the preferred lying position was unknown in five cases. The deformity occurred on the right side in 24 cases and 14 cases had left occipital plagiocephaly, including three twins. One patient had bilateral occipital flattening. On review of other aetiological and associated factors there were eight cases with torticollis and one with strabismus. Five babies were slow to sit up due to hypotonia and developmental delay (4) and phocomelia (1). Three patients had mild hydrocephalus (one required a temporary ventriculo-peritoneal shunt). Indications of intrauterine aetiology were found in five cases (one polyhydramnios, one transverse lie, three twins but only one was diagnosed occipital plagiocephaly at birth). There were two cases of suspected lambdoid synostosis with a severe worsening deformity. Both had posterior cranioplasties with satisfactory results. With the exception of the cases with mild hydrocephalus, head circumferences were within normal ranges at all visits for all patients. Photographs were very difficult to standardise and were not a useful objective assessment of the deformity. X-ray findings were difficult to interpret (Figs 1, 2) and showed a degree of sclerosis and petrous bone deformity in the operative cases, but no definite fused
suture was seen nor was synostosis of the asterion noted on review of any of the plain films. No comment could be made on the severity of the deformity or on its progression on serial X-rays. Three-dimensional CT was useful in cases undergoing surgery, but the radiation dose and the anaesthetic were deemed unnecessary for most patients. Surface scanning using a colour light striping technique with computer 3-D reconstruction was not useful, as landmarks and features were masked by hair. Parents scored their impression of the severity of the deformity when first diagnosed and at the time of the study on a simple 1–5 scale (1 = normal, 2 = mild deformity, 3 = obvious deformity, 4 = severe deformity, 5 = very severe deformity).15 Thirty-three questionnaires were returned. The mean improvements over time were scored by the parents as shown in Figure 3. A Student t-test showed a significant difference between scores at diagnosis and after 1 year (P = 0.05), indicating a definite improvement, but complete resolution did not occur in most cases. There was no statistically significant difference between early and late diagnosis groups (Fig. 3A). There was a trend towards increasing severity in cases with torticollis both at diagnosis and after 1 year but while not surprising, this was not statistically significant (Fig. 3B). Discussion The Temple Street Craniofacial Unit serves a population of approximately three million; the estimated incidence is therefore 1/75,000. This is probably a significant underestimate, as many mild cases are not referred and an incidence as high as 1/300 has been reported.16 Neonatal moulding caused by compression forces during labour may account for some of these, but there is little doubt that this is an underdiagnosed condition. Moulding occurs in up to 48% of neonates,
Posterior plagiocephaly: proactive conservative management 5 4.5 4 3.5 3 Y 2.5 2 1.5 1 0.5 0
Early diagnosis n=9 Later diagnosis n = 24
At diagnosis
After one year
Figure 3A—Improvement in perception of severity scores with time showing early and late referral cases separately.
Figure 4—Diagram of foetal head in left occipito-anterior position in pelvis: growth constraint occurs in right occiput.
leading to mild temporary cranial deformities which resolve within 6 weeks.1,2 The incidence of plagiocephaly has risen in countries adopting paediatricians’ recommendations promoting the supine sleeping position in order to reduce the risk of SIDS.17–19 It is also interesting that 18 out of 24 patients diagnosed after 2 months habitually slept on the flattened side of the occiput. This is in keeping with an 80% correlation found by Argenta et al.17 Five of these patients were slow to gain head control and eight had the classical association with torticollis, which also forces the baby to lie on one side and may also apply direct deformational forces to the occiput. In keeping with many other studies there is a predominance of right-sided plagiocephaly (23:15). These data support the theory that external deformational force is the most significant factor leading to posterior non-synostotic plagiocephaly. The problem may start in utero as 85% of vertex presentations lie in the left occipital anterior position in the pelvis which may constrain growth in the R occipital and L frontal regions if early pelvic descent occurs (Fig. 4).1,2 This growth constraint is further perpetuated if the infant preferentially lies on the flattened side. Additional evidence supporting this hypothesis includes the fact that the condition is more common in multiple pregnancies, with abnormal foetal lie and uterine abnormalities, although our figures are too small to demonstrate a definite relationship.2 It has been reported that the
21 5 4.5 4 3.5 3 Y 2.5 2 1.5 1 0.5 0
With torticollis n=7 Without torticollis n = 26
At diagnosis
After one year
Figure 3B––Improvement in severity score in patients with and without torticollis.
Figure 5—Illustrations with superior and posterior views showing main clinical differences between true lambdoid synostosis (left) and deformational plagiocephaly (right).
length of time required to produce a lasting deformation of the cranium is several weeks to 3 months.20 For years, the distinction between deformational plagiocephaly and lambdoid synostosis was based not on differences in skull pattern, but rather on evidence of progression of deformity.4 Non-synostotic plagiocephaly gives rise to a rhomboid-shaped cranium when observed from above. There is occipital flattening, contralateral bossing and ipsilateral forehead bossing producing a parallelogram or rhomboid shape. In addition there is anterior displacement and prominence of the ipsilateral ear, but little tilt of the skull base,4 as shown on the right set of diagrams in Figure 5. According to some authors, in more severe cases the ipsilateral malar eminence also projects with the forehead.1,2,17 Patients with true lambdoid synostosis, shown on the left in Figure 5, also have a flattened occiput, but in addition have contralateral parietal bossing and contralateral frontal bossing giving rise to a trapeziumshaped head.4 The ipsilateral ear is displaced inferiorly and posteriorly and the skull base is tilted likewise. In cases of true lambdoid synostosis, there will also be external ridging of the fused suture as is found in other craniosynostoses. While the patients should be photographed for documentation purposes, we found this modality very
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Figure 6—Three-dimensional CT scan of posterior skull showing asymmetry but normal lambdoid suture.
Figure 7—Three-dimensional CT scan, lateral view, showing asymmetry but normal lambdoid suture and asterion.
limited in objective assessment of the deformity. To get standardised views without a cephalostat is difficult and, in our experience, the deformity does not project very well in a 2-D format. Plain skull X-rays may show obliteration of the lambdoid suture, but the sign most frequently referred to is bone sclerosis adjacent to the suture.10 We would question the validity of this sign, as sclerosis may be secondary to deformational forces and therefore not an indication of synostosis, functional or otherwise. In severe and especially bilateral cases there may be copper beating of the posterior cranial fossa, although this is unusual. The petrous bone may also be deformed in more severe cases, with depression of the petrous ridge and semicircular canals seen on Towne projection.12 In our experience, most of these signs can be vague and may not be helpful in borderline cases (Figs 1, 2). Asterion synostosis is another X-ray finding based on a new theory that many borderline cases may not have lambdoid synostosis, but have an isolated area of fusion in the asterion (junction of parietal, occipital and temporal bones).11 This area can be difficult to see on plain film and may need 3-D CT to obtain clear views (Figs 6, 7). We report no cases in this series with this finding. Technecium radionucleotide bone scanning may show increased activity during the active phase of bony union, but will show decreased activity once union has occurred. The suture’s activity can be compared with its contralateral partner bearing in mind that it has been demonstrated that the lambdoid suture is at its most active in a 3month-old baby. Proponents of this technique claim that this investigation can be very helpful, but it is questionable whether the radiation dose involved is acceptable in most cases.10 Both CT and 3-D CT (Figs 6, 7) demonstrate the deformity in a qualitative fashion and until recently were not very helpful in distinguishing subtypes of plagiocephaly. It has been found that even experienced neuro-radiologists were inconsistent in distinguishing between lambdoid synostosis and deformational plagiocephaly.13 A useful objective method of distin-
guishing between these two entities has been described, which is based on the angles between the central axis of the anterior and the posterior cranial fossae with a bird’s-eye view of the endocranial base on 3-D CT scans.13 Unfortunately a useful tool for quantitative assessment of progress of the condition has not been described. While it is feasible to take standardised CT cuts at a set level above and parallel to the Frankfort plane and with specialised software to obtain volume/symmetry indices from 3-D CT reconstructions, these methods of follow-up would require multiple CT scans and significant radiation exposure. We consider the radiation dose and the necessary paediatric general anaesthetic unjustified even for a single scan, unless surgery is being seriously considered. Another possibility is the use of 3-D MRI scans, but this is also expensive, involves highly specialised software and requires a general anaesthetic. Our unit has access to a 3-D surface scanner which was proposed as an alternative to CT for objective follow-up, but this technique, using either a laser or a collimated light source is unhelpful, as hair on the back of the head disperses light. Our results show that while nearly all patients improve with conservative treatment, most retain mild deformity and it is unlikely that this will resolve as the child grows.20 We therefore feel that changing the babies’ sleep positions alone may not be the optimal treatment. Helmet treatment was first described by Clarren et al in 1979,21 but has only recently gained popularity and it is possible that even some severe non-synostotic cases may respond to this therapy. It requires a specialised technician, as all helmets must be custom designed for the needs of the patient. It is also important that this treatment is instituted early, as it is ineffective if started after the age of 6 months.22 The effectiveness of this technique when compared with repositioning alone has not been established in any controlled series.19 Finally, it is agreed by most that there is a small subgroup of patients who have severe progressive positional deformities who require surgical
Posterior plagiocephaly: proactive conservative management
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intervention, as was the case for two patients in this study group who required posterior cranioplasty.23
11. Jimenez DF, Barone CM, Argamaso RV, Goodrich JT, Shprintzen RJ. Asterion region synostosis. Cleft Palate Craniofac J 1994; 31: 136–41. 12. Fernbach SK, Feinstein KA. The deformed petrous bone: a new plain film sign of premature lambdoid synostosis. Am J Roentgenol 1991; 156: 1215–17. 13. Lo L-J, Marsh JL, Pilgram TK, Vannier MW. Plagiocephaly: differential diagnosis based on endocranial morphology. Plast Reconstr Surg 1996; 97: 282–91. 14. McComb JG. The sunrise technique: the correction of occipital plagiocephaly using bandeau occipital plate and radial osteotomies (discussion). Pediatr Neurosurg 1995; 22: 166. 15. Vander Kolk CA, Carson BS. Lambdoid synostosis. Clin Plast Surg 1994; 21: 575–84. 16. Dunn PM. Congenital postural deformities. Br Med Bull 1976; 32: 71–6. 17. Argenta LC, David LR, Wilson JA, Bell WO. An increase in infant cranial deformity with supine sleeping position. J Craniofac Surg 1996; 7: 5–11. 18. American Academy of Pediatrics (AAP) task force on infant positioning and SIDS: positioning and SIDS. Pediatrics 1992; 89: 1120–6. 19. Persing JA. The differential diagnosis of posterior plagiocephaly: true lambdoid synostosis versus positional molding (discussion). Plast Reconstr Surg 1996; 98: 775–6. 20. Ripley CE, Pomatto J, Beals SP, Joganic EF, Manwaring KH, Moss SD. Treatment of positional plagiocephaly with dynamic orthotic cranioplasty. J Craniofac Surg 1994; 5: 150–9. 21. Clarren SK. Plagiocephaly and torticollis: etiology, natural history, and helmet treatment. J Pediatrics 1981; 98: 92–5. 22. Clarren SK, Smith DW, Hanson JW. Helmet treatment for plagiocephaly and congenital muscular torticollis. J Pediatrics 1979; 94: 43–6. 23. Lin K, Opperman L, Nolen A, et al. Surgical approach to posterior skull deformities. Presented at 6th Congress of the International Society of Craniofacial Surgery, St Tropez, France, 1995.
Conclusions As the incidence of this controversial condition increases dramatically, it is necessary that craniofacial surgeons develop a better understanding of posterior plagiocephaly and come to a consensus view on its management. At present, clinical assessment and follow-up is the most reliable method for deciding whether surgery will be necessary, although CT of the endocranial base may also be helpful. There are no ideal objective techniques at present to monitor the deformity over time and this area remains a challenge. Helmet treatment may play an important role in the conservative management of these patients as simple conservative methods can sometimes be disappointing. References 1. Hansen M, Mulliken JB. Frontal plagiocephaly: diagnosis and treatment. Clin Plast Surg 1994; 21: 543–53. 2. Bruneteau RJ, Mulliken JB. Frontal plagiocephaly: synostotic, compensational, or deformational. Plast Reconstr Surg 1992; 89: 21–31. 3. Gosain AK, Steel M, McCarthy JG, et al. A prospective study of the presentation and outcome of strabismus and head posture in patients with plagiocephaly. 5th International Congress of the International Society of Craniofacial Surgery, Oaxaco, Mexico, 1993. 4. Huang MHS, Gruss JS, Clarren SK, et al. The differential diagnosis of posterior plagiocephaly: true lambdoid synostosis versus positional molding. Plast Reconstr Surg 1996; 98: 765–74. 5. David JD, Poswillo D, Simpson D. The craniosynostoses: causes, natural history and management. New York: Springer–Verlag, 1982, 23–6. 6. McComb JG. Treatment of functional lambdoid synostosis. Neurosurg Clin North America 1991; 2: 665–72. 7. Cohen MM Jr. Sutural biology and the correlates of craniosynostosis. Am J Med Gen 1993; 47: 581–616. 8. Sitsen AE. Zur entwicklung der nahte des schledeldaches. Z Anat Entwicklungsglesch 1993; 101: 121–51. 9. Hinton DR, Becker LE, Muakkassa KF, Hoffman HJ. Lambdoid synostosis: Part 1; The lambdoid suture: normal development and pathology of ‘synostosis’. J Neurosurg 1984; 61: 333–9. 10. Muakkassa KF, Hoffman HJ, Hinton DR, Hendrick EB, Humphrey RP, Ash J. Lambdoid synostosis: Part 2; Review of cases managed at the Hospital for Sick Children, 1972–1982. J Neurosurg 1984; 61: 340–7.
The Authors E. S. O’Broin, MMedSc, FRCSI, Registrar in Plastic and Reconstructive Surgery, Cork University Hospital, Wilton, Cork, Republic of Ireland. D. Allcutt, FRCS, Consultant Neurosurgeon, M. J. Earley, MCh, FRCS (Plast), Consultant in Plastic and Reconstructive Surgery, Temple Street Children’s Hospital, Dublin, Republic of Ireland. Correspondence to Mr M. J. Earley. Paper received 1 October 1997. Accepted 18 September 1998, after revision.