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Occipital plagiocephaly
British Journal of Plastic Surgery (2000), 53, 367 377 9 2000 The British Association of Plastic Surgeons doi:10.1054/bjps.2000.3329
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Occipital plagiocephaly D. J. David and R. M. Menard*
Australian Craniofacial Unit, Women's and Children's Hospital, North Adelaide, South Australia and * University of Adelaide, South Australia SUMMARY. The diagnosis of occipital plagiocephaly has remained a complex and controversial issue in the field of craniofacial surgery. Over the past 30 years, numerous studies have been published describing the management and treatment for 'posterior plagiocephaly', 'plagiocephaly without synostosis', 'deformational plagiocephaly' and 'occipital plagiocephaly', with surgical 'correction' being chosen as the primary modality of treatment irrespective of the patency status of the lambdoid sutures. Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Each patient was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Only two of the 204 patients (- 1%) manifested the clinical, radiographic and pathological features of true unilambdoid synostosis. There was radiographic evidence of sutural fusion on plain films, 2-D and 3-D CT scans. Pathology specimens showed bony sutural fusion. Two hundred and two patients presented with unilateral occipital deformities and patent sutures on radiography. These patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (211204) included patients with severe plagiocephaly not responding to conservative therapy (191204) and the two patients with true unilambdoid synostosis (21204). One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement, one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. In our series it is apparent that the majority of cases of occipital plagiocephaly are not secondary to true synostosis and can be managed by conservative positional measures. 9 2000 The British Association of Plastic Surgeons Keywords: craniofacial surgery, occipital plagiocephaly, posterior plagiocephaly, conservative treatment, positional treatment, surgical correction, lambdoid synostosis.
The management of infants with occipital plagiocephaly has remained an area of controversy in the fields of paediatrics, neurosurgery and craniofacial surgery over the past 30 years. The deformity has been ascribed to a variety of extrinsic and intrinsic factors, including aberrant constraint of the foetal head in the intrauterine environment, ~ congenital muscular torticollis,24 preferential sleeping position in early infancy5,6 and secondary effects of cranial base abnormalities. 7 The initial asymmetry that may exist at birth is exacerbated by a persistent positional preference, with the infant resting its head on the flatter occipital surface. This in turn gives rise to the secondary cranial vault deformities, resulting in the 'parallelogram' head shape and asymmetrical ear position. There has been a wide and varied array of management strategies used on infants with occipital plagiocephaly, with treatment protocols based as much o n an individual's preference to operate as on objective factors. In certain studies, the initial management of infants with occipital plagiocephaly consisted of
lambdoid strip craniectomies 8,9 or posterior calvarial remodelling~~ despite radiographic and pathological evidence indicating patent lambdoid sutures. In the light of the non-synostotic nature of the overwhelming majority of the patients and the perceived need for an 'active' therapy, other studies have looked at normalising head shape through the use of an external orthosis. 4,6,12,13 Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Over that period of time a management protocol has been developed incorporating conservative positioning and physiotherapy treatment as the primary intervention in cases of non-synostotic occipital plagiocephaly; a treatment plan supported in recent literature. ~4 In those patients with severe plagiocephaly not responding to conservative therapy or with true unilambdoid synostosis, surgical correction was used towards normalising head shape. Where surgical correction was undertaken it was to release the fused suture to allow brain growth to influence the calvarial shape. 367
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C Figure 1--Unilambdoid synostosis.(A) AP plain film radiograph, right unilambdoid synostosis.Note 'copper beating' of right occipital region, right occipitomastoidbossing, right inferior skull base tilt, absent right lambdoid suture line, and facial asymmetry. (B) 2-D CT scan axial views infantwith right unilambdoid synostosis. Note patent left lambdoid suture and fused right lambdoid suture, with evidenceof occipital 'copper beating' and associated right occipitalflattening. (C) Posterior 3-D CT scan right unilambdoid synostosis.Fusion of the right lambdoid suture, prominent occipitomastoidbossing and right inferior tilt of the skull base is evident. The horizontal line denotes the levelof the axial 2-D CT image in Figure lB.
B Patients and methods
From January 1981 to July 1997, 204 children were referred to the Australian Craniofacial Unit, Adelaide, South Australia, for the evaluation and management of occipital plagiocephaly. The mean age of the infants at presentation was 6 months, with a range of 6 weeks to 24 months. The average current age o f patients in the series is 7 years. Each infant was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Clinical findings
and associated factors were documented, including age at presentation of deformity, birth history, history of torticollis or positional preference, history of developmental delay, severity of the deformity as seen clinically and radiologically, and ear position. All children were photographed at a minimum o f 1-year intervals. Patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (21/204) included patients with severe plagiocephaly not responding to conservative therapy (19/204) and two patients with true unilambdoid synostosis (2/204). Resected lambdoid suture specimens were evaluated histologically.
Results
O f the 204 patients with unilateral occipital deformities, only two patients (~ 1%) manifested the clinical, radiographic and pathological features of true lambdoid synostosis. Radiographically, there was evidence of sutural fusion on plain films, 2-D and 3-D CT scans (Fig. 1 A-C). Two hundred and two patients were noted to have patent lambdoid sutures on radiography
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Figure 2 Vertexview - deformational occipital plagiocephaly versus unilambdoid synostosis. (A) Infant with right-sided deformational occipital plagiocephaly. Note the right occipitoparietal flattening with prominent left occipital posterior bossing and right frontal bossing, resulting in a parallelogram head shape. (B) Infant with right unilambdoid synostosis. Note the prominent left parietal bossing with associated right occipitoparietal flattening, trapezoid head shape and right anterior ear displacement.
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Figure 2~-Posterior 3-D CT scan soft tissue view deformational occipital plagiocephaly versus unilambdoid synostosis. (A) Infant with right-sided deformational occipital plagiocephaly. (B) Infant with right unilambdoid synostosis. Note the horizontal posterior skull base in the infant with right-sided deformational occipital plagiocephaly; the infant with right unilambdoid synostosis displays a prominent occipitomastoid bulge, a compensatory twist of the cervical spine and a right inferior tilt of the skull base with inferior displacement of the right ear.
consistent w i t h d e f o r m a t i o n a l occipital plagiocephaly. These patients were g r o u p e d a c c o r d i n g to the severity o f their d e f o r m i t y as d e s c r i b e d by Clarren. 4 T h e r e were 84 patients with mild deformities (less t h a n 5 ~
difference), 90 with m o d e r a t e deformities (5-10 ~ difference) a n d 30 with severe deformities (greater t h a n 10 ~ difference). O n e h u n d r e d a n d t h i r t y - f o u r p a t i e n t s d i s p l a y e d a r i g h t - s i d e d occipital deformity, while there
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Figure4--Posterior 3-D CT scan bone view deformationaloccipitalplagiocephalyversus unilambdoidsynostosis.(A) Infant with right-sideddeformationaloccipitalplagiocephaly.(B) Infant with right unilambdoidsynostosis.Note the horizontalposterior skull base, visible bilateral lambdoidsutures and lack of parietal or occipitomastoidbossingin the infant with right-sideddeformationaloccipital plagiocephaly.In the infant with right unilambdoidsynostosis,fusion of the right lambdoidsuture, prominentoccipitomastoidbossingand right inferiortilt of the skull base are evident. were 70 left-sided deformities (65.7% right-sided versus 34.3% left-sided). Males outnumbered females 130 to 74 (64% male versus 36% female). A history of positional preference in infancy was seen in 48% of the patients (98/204), whereas torticollis was seen in 24% of the patients (49/204). Developmental delay was seen in 6% (12/204). Of the 202 patients with non-synostotic deformational occipital plagiocephaly, 19 were noted to have severe deformities that did not respond to head positioning and physiotherapy measures. These patients underwent occipital craniectomy with lambdoid suture resection at an average age of 7.6 months. All of these patients showed the apparent 'sclerosis' of the lambdoid suture, a sign that was given some significance at that time. A review of the histology showed that a patent suture was identifiable in each case. Only one of these patients was felt to be without notable improvement in cranial contour and symmetry as judged by their parents postoperatively. In addition to the radiological differences between the patients with true lambdoid synostosis and deformational occipital plagiocephaly, morphological differences were noted between them as well. Both deformational occipital plagiocephaly and unilambdoid synostosis patients presented with unilateral occipitoparietal flattening associated with contratateral posterior bossing. In the deformational patients, this posterior bossing was seen primarily in the occipital region, while in the synostotic patients it was seen more laterally and superiorly in the parietal region (Fig. 2A, B). In the two synostotic patients, a
prominent occipitomastoid bulge was present which was not seen in the deformational patients (Fig. 3A, B). In the two synostotic patients the posterior skull base was tilted inferiorly towards the affected side, with a compensatory twist in the cervical spine (Fig. 4). Secondary to the tilt in the posterior skull base, the ipsilateral ear was displaced inferiorly; when viewed from the vertex or from below, the two synostotic patients displayed anterior ear displacement, which is clearly demonstrated in the soft tissue 3-D CT images (Fig. 5). The patients with deformational occipital plagiocephaly displayed an essentially horizontal posterior skull base, with anterior ear displacement corresponding to the severity of their deformity (Fig. 4A, 5A). One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement performed on a patient presenting after infancy and one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. Discussion
In 1982, David et al published our results of patients with posterior (occipital) plagiocephaly; they constituted 9.6% of our series of simple synostoses. 15 We noted at the time that 'most of the cases classified as
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12 Figure 5--Basal 3-D CT scan soft tissue view deformational occipital plagiocephalyversus unilambdoid synostosis. (A) Infant with right-sided deformationaloccipitalplagiocephaly.Note the anterior ear displacementcorrespondingto the severityof the deformity,and lack of parietal or occipitomastoidbossing. (B, C) Two infants with right unilambdoid synostosis.Note moderate right anterior ear displacement,right occipitomastoidbulge, right occipital flatteningand left parietal prominence.
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unilambdoid synostosis fusions showed only sutural sclerosis without radiological evidence of fusion'. It was our view at the time, as it is now, that true lambdoid synostosis is a rare event. Much of the recent literature on the subject refers to the diagnosis and treatment of posterior plagiocephaly as being 'controversial'. 13'14'16'17What is the nature of this controversy and how has it come about?
Frequency In the current series the incidence of true lambdoid synostosis is very low (~ 1%). What has occurred is a
massive increase in the awareness of, reporting of and management of posterior (occipital) plagiocephaly. The 1970s saw the advancement of craniofacial surgery and, with it, the increasing concern of parents, family doctors, obstetricians and paediatricians, as well as neurosurgeons and cranio-facial surgeons. Early on, it was established that correction of synostosis of the coronal ring of sutures in frontal plagiocephaly due to synostosis of these sutures, when performed in the first few months of postnatal life, frequently gave long-lasting results and prevented disfiguring facial asynametry? s,18,~9The importance of making this early diagnosis raised the awareness first of the medical community and later of the general public of the importance of noting the skull shape in the neonate, since early appropriate intervention could prevent a permanent disfiguring craniofacial deformity. Paediatricians and orthopaedic surgeons have long recognised the association of torticollis and occipital plagiocephaly, and indeed made the association o f the deformity with external deformational forces. 4 The very significant papers by Muakkassa et al and Hinton et al 8,2~emanating from the Hospital for Sick Children in Toronto, presented the view that lambdoid 'synostosis' is different from other forms of synostosis, and that 'bone union (of isolated lambdoid synostosis sutures) was an unusual feature'. 2~ This paper was coupled with a review of cases from 1972 to 1982 reporting an incidence o f lambdoid synostosis of
372 18.5% and reporting that the results of linear craniectomy produced excellent or good results in the majority of patients. The implication at the end of the discussion that there may be some functional problems resulting from uncorrected single suture synostosis, as suggested by Renier et al 2~ (although without any particular reference to the lambdoid suture) added to the force of the argument for surgery. A summary of their position was that 'the condition is underdiagnosed; it can be diagnosed with proper awareness and state of the art radiological and nuclear medicine techniques; there are observable histological changes in the sutures; surgery produces 96% excellent or good result, and may save some patients having raised intracranial pressure.' We believe that these papers, coming as they did from such an excellent centre, had a very significant effect on the established neurosurgical and the emerging craniofacial surgical communities. Increased awareness, together with an increased tendency for correction of the skull deformity of posterior plagiocephaly by helmet moulding or by increasingly complex surgical manoeuvres 22,23resulted in more cases of posterior plagiocephaly being reported, with a greater proportion of these cases being ascribed to lambdoid synostosis and treated. In some cases the community saw this increase as an epidemic 24 that needed investigation and explanation. More recently, the 'back to sleep' campaign instituted in the USA in 1992 has been implicated, with the strict supine sleeping position suggested as.increasing the incidence of infants with deformation of the craniofacial skeleton. 5 The steady increase in the number of cases presenting to the Australian Craniofacial Unit support the view that this and similar campaigns have had an influence on the number of patients with deformed heads presenting for management.
Pathology In the rare cases of true lambdoid synostosis there was bony fusion across the lambdoid suture25 In this matter we agree with the recent publication by Huang et al. 16 The equivocal findings of variations, both at operation and radiologically, that give credibility to the special status of the lambdoid suture as one that may act in a 'sticky' fashion, may be explained by a casuistic zeal to justify surgical intervention, or by the possibility as suggested by Hinton et al 2~that some of these more subtle changes may be due to the increased stress of deformation early in the development of the suture. Save for the two cases of true lambdoid synostosis that we have described 25 and the patients described by Huang et a116 that differ markedly radiologically, morphologically and histologically from the majority of occipital plagiocephaly patients described, there was no evidence of complete bony fusion described in many of the operative cases of occipital plagiocephaly described in the literature2 ~
Clinical diagnosis Both deformational occipital plagiocephaly and unilambdoid synostosis patients presented with unilateral
British Journal of Plastic Surgery occipitoparietal flattening associated with contralateral posterior bossing; this contralateral bossing was primarily occipital in the deformational patients and parietal in the unilambdoid synostosis patients. The absence of any real orbital deformity or significant supraorbital depression clearly distinguishes the condition from frontal plagiocephaly. The diagnostic problem has been to distinguish deformational occipital plagiocephaly from unilambdoid synostosis, both clinically and radiologically. As we noted in 1982, the history may not be helpful, since the tendency to lie on one side could be the effect as well as the cause of the deformity. Prior to the article by Huang et a116 there had been no detailed anatomical description of the distinction between the diagnoses of unilambdoid synostosis and deformational plagiocephaly. This diagnostic problem was and is no light problem. In one case, early surgery on the posterior skull is sometimes required to prevent significant craniofacial deformity; in the other, with few or no exceptions, no surgical intervention is required and the natural history is one of relative self-correction. Confusion has led to many cases of unnecessary surgery and, indeed, some justified community anxiety resulting from this. 24,27 The findings of our study corroborate the findings of Huang et aP 6 with one important exception: the anteroinferior ear displacement seen on the side affected by unilambdoid synostosis. Both studies show the distinct features of unilambdoid synostosis versus deformational occipital plagiocephaly: 1. Contralateral posterior bossing occurring in the parietal region in patients with unilambdoid synostosis versus occipital bossing in patients with deformational occipital plagiocephaly. 2. Ipsilateral occipitomastoid bossing was seen in both patients with unilambdoid synostosis, but was absent in patients with deformational occipital plagiocephaly. 3. Ipsilateral inferior tilt of the posterior skull base was seen in patients with unilambdoid synostosis versus a horizontal skull base in deformational occipital plagiocephaly. 4. A trapezoid head shape as viewed from the vertex was seen in patients with unilambdoid synostosis versus a parallelogram head shape in deformational occipital plagiocephaly. With respect to ear position, there is an important difference between the anteroinferior ear displacement seen in our two cases and the posterior ear displacement as described by Huang et al? 6 The moderate anterior ear displacement seen in our cases can be explained by the pronounced occipitomastoid compensatory growth seen in the two patients with lambdoid synostosis, along the growth vector lines as described by Huang et al. ~6 In former, less discriminating times, others have also seen the anterior ear displacement in true lambdoid synostosis. 21 Extreme care should be exercised in making a diagnosis of unilambdoid synostosis - relying on single parameters such as ear position is superficially attractive, but in reality is an attempt to induce a general rule from a very small sample of true
Occipital plagiocephaly
Figure 6--2-D CT scan axial image, severe right deformational occipital plagiocephaly. Note prominent right inner table ridging, end-to-end suture pattern and associated right occipital flattening.
synostotic cases and, as is shown in this paper, soon falsified.
Radiological diagnos& In our series, all patients underwent plain radiographs of the skull. Both patients with lambdoid synostosis demonstrated 'copper beating' of the affected occipital region, with associated occipitomastoid bossing, inferior ipsilateral skull base tilt, absent suture line and secondary facial cant. 25 Two- and three-dimensional CT scans performed on these patients reiterated these findings. 25 Sutural fusion was seen on the 2-D CT slices and the 3-D CT reconstruction and clearly demonstrates the gross anatomy. Muakkassa and colleagues in 1984 rightly pointed out that the radiological features of lambdoid synostosis were at that stage not well documented) They went on to place great diagnostic importance on the presence of a sclerotic line along the superior or inferior edge of the lambdoid suture, stating that the suture may appear patent but functioned as if completely united. This diagnostic aid was taken up and treated as being of great significance. Our early surgical interventions on severe deformational cases were made on the basis of the association of this radiological sign with the deformation, using the causal proposition that such a suture would function in an abnormal way and therefore needed to be released. It is of interest to note that three of Muakkassa's 74 cases of lambdoid 'synostosis' demonstrated the local 'copper beaten' appearance. If we presume for argument's sake that this is a more reliable sign of lambdoid synostosis, then three cases out of 404 (~ 0.75%) rather than 74 of 404 (18.5%) is more in
373 line with the incidence of true lambdoid synostosis seen in this paper and that of Huang et al. 16 What then of the findings in axial CT scans showing an end-to-end suture pattern, associated with thickening of the inner cortex around the suture (Fig. 6)? Vander Kolk and Carson 23 clearly made this sign a feature of lambdoid synostosis, citing papers by Hinton et al, 2~ Laitinen and Sulamoa 28 and unpublished work by Cohen MM, in support of this view. Like Huang et all 6 we do not believe that this is a sign of sutural fusion; more likely, it is a response to the postural abnormality of deformational plagiocephaly. Pople et a129 proposed an interesting theory as to why patients with severe deformational plagiocephaly do not respond completely to conventional positioning measures. They suggested that the pronounced inner table ridging that is seen in patients with severe deformational occipital plagiocephaly results in a 'locked' lambdoid suture, causing the deformity to worsen. This theory has the elements of a more sophisticated restatement of the 'sticky' suture concept. These patients, however, should not be diagnosed as having unilambdoid synostosis because their cranial morphology differs markedly, as described, 16,25and their sutures are patent when examined histologically in Menard and DavidY
Treatment O f the 202 patients with deformational plagiocephaly, 19 (9.4%) underwent occipital craniectomy secondary to their severe deformity not responding to conservative management and being associated with the 'sclerotic' suture sign. There was the mistaken view that this combination of events represented sutural pathology, resulting in the deformity. All of these patients initially responded well to the surgery, yet they all remain with some residual deformity, even after many years (Fig. 7). This residual deformity is mostly covered by hair and of no cosmetic significance in all but two patients, in whom the deformity recurred relentlessly and persisted. Of those patients managed conservatively, that is with positioning and/or physiotherapy, the deformity is rarely if ever corrected completely (Fig. 8), but has never become a source of major concern. The facial deformity is rarely even perceptible and the residual occipital deformity, more readily seen on radiography, is hidden by the hair. The two patients with lambdoid synostosis treated by craniectomy in infancy have had their deformity corrected and this has been maintained with growth (Fig. 9). The use of helmet therapy for the management of the severe deformational patients has been described, 4,13but in the light of the natural history of all but a very few of these cases to improve to a level where the deformity is hardly noticeable, the question has to be asked whether even this degree of intervention is necessary or justified. Of the two severe cases of deformational plagiocephaly that underwent surgery and suffered progressive recurrent deformity we cannot shed any light to date on the particular aspects of the pathology and pathogenesis that are at work in these patients.
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Figure 7 Severe deformational occipital plagiocephaly with operative treatment (lambdoid craniectomy and posterior calvarial remodelling at 6 months of age), 8-year follow-up. (A) Vertex view, 6-month-old girl with severe right deformational occipital plagiocephaly, preoperative analysis. (B) Plain radiograph, basilar view, preoperative. Note the severe right occipital flattening and posterior contom irregularity. (C) Vertex view, 10 months old, 4 months postoperatively. Note the improved frontal contour with slight residual left frontal flattening. (D) Vertex view, 6 years old, 5 years and 6 months postoperatively. (E) Vertex view, 8 years and 6 months old, 8 years postoperatively. Note the adequate frontal contour, with the occipital contour concealed by hair growth.
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Figure 8 Moderate deformational occipital plagiocephaly with non-operative treatment, 6-year follow-up. (A) Vertex view, 8month-old girl with moderate right deformational occipital plagiocephaly. Note the right anterior ear displacement, left frontal flattening and right occipital flattening. (B) Plain radiograph, basilar view. Note the moderate right occipital flattening and posterior contour irregularity. Townes view revealed patent lambdoid sutures bilaterally. (C) Vertex view, 3 years and 8 months old. Note the improved frontal contour and occipital contour concealed by hair growth. (D) Vertex view, 6 years and 9 months old. (E) Plain radiograph, basilar view, 6 years and 9 months old. Note the improved posterior contour versus Figure 8B.
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Figure 9--True right unilambdoid synostosis with operative treatment (lambdoid craniectomy and posterior calvarial remodelling at 8 months of age), 5-year follow-up. (A) Vertex view, 8-month-old boy with right unilambdoid synostosis, preoperative analysis. Note the prominent left parietal bossing with associated right occipitoparietal flattening, trapezoid head shape and right anterior ear displacement. (B, C) AP and basilar plain films, preoperative. Note 'copper beating' of right occipital region, right occipitomastoid bossing, right inferior skull base tilt, absent right lambdoid suture line, and facial asymmetry. (D) Vertex view, 11 months old, 3 months post lambdoid craniectomy and posterior calvarial remodelling. (E) Vertex view, 6 years old, 5 years and 4 months post lambdoid craniectomy and posterior calvarial remodelling. Note the improved frontal contour and residual right anterior ear displacement. (F) Plain film, basilar view, 5 years and 4 months post lambdoid craniectomy and posterior calvarial remodelling.
Conclusion In the light of anatomical, radiological and histological studies m a d e over m a n y years, together with longterm follow-up of patients with occipital plagiocephaly, it can now be said that the morphological characteristics of patients with true unilambdoid synostosis differ significantly from those of patients with deformational occipital plagiocephaly. These findings include ipsilateral occipitomastoid bossing posterior ipsilateral skull tilt, contralateral parietal bossing and anteroinferior ear displacement. The diagnostic imaging and pathological findings are consistent with other forms of craniosynostosis, displaying bony sutural fusion.
Patients with occipital plagiocephaly should be carefully reviewed with clinical and diagnostic imaging examinations to describe the cranial m o r p h o l o g y accurately and assess the patency of the lambdoid sutures. Most cases of occipital plagiocephaly are secondary to deformational forces and will achieve satisfactory correction with conservative management. A few cases of nonsynostotic progressive deformity remain a mystery and warrant further close study. Progress in the understanding of the natural history and m a n a g e m e n t of occipital plagiocephaly has been an interesting one, with a retreat from surgical treatment in the deformational cases once the diagnostic criteria and natural history have been clarified.
Occipital plagiocephaly References 1. Clarren SK, Smith DW. Congenital deformities. Pediatr Clin North Am 1977; 24: 665-77. 2. Coventry MD, Hains LE. Congenital muscular torticollis in infancy. J Bone Joint Surg 1959; 41A: 815. 3. Dunn PM. Congenital sternomastoid torticollis. An intrauterine postural deformity. Arch Dis Child 1974; 49: 824. 4. Clarren SK. Plagiocephaly and torticollis: etiology, natural history, and helmet treatment. J Pediatr 1981; 98: 92-5. 5. Turk AE, McCarthy JG, Thorne CH, Wisoff JH. The "back to sleep campaign" and deformational plagiocephaly: is there cause for concern? J Craniofac Surg 1996; 7: 12-18. 6. 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. 7. Moss ML. New studies of cranial growth. Birth Defects 1975; 11: 283-95. 8. Muakkassa KF, Hoffman H J, Hinton DR, Hendrick EB, Humphreys 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. 9. Dias MS, Klein DM, Backstrom JW. Occipital plagiocephaly: deformation or lambdoid synostosis? I. Morphometric analysis and results of unilateral lambdoid craniectomy. Pediatr Neurosurg 1996; 24: 61-8. 10. McComb JG. The sunrise technique: the correction of occipital plagiocephaly using bandeau occipital plate and radial osteotomies (Discussion). Pediatr Neurosurg 1995; 22: 166. 11. Jimenez DF, Barone CM. The sunrise technique: the correction of occipital plagiocephaly using bandeau occipital plate and radial osteotomies. Pediatr Neurosurg 1995; 22: 162-5. 12. Ripley CE, Pomatto J, Beals SE Joganic EF, Manwaring KH, Moss SD. Treatment of positional plagiocepbaly with dynamic orthotic cranioplasty. J Craniofac Surg 1994; 5: 150-9, 13. Pollack IF, Losken HW, Fasick P. Diagnosis and management of posterior plagiocephaly. Pediatrics 1997; 99: 180-5. 14. O'Broin ES, Allcutt D, Earley MJ. Posterior plagiocephaly: proactive conservative management. Br J Plast Surg 1999; 52: 18-23. 15. David DJ, Poswillo D, Simpson DA. The Craniosynostoses: Causes, Natural History and Management. Berlin/ Heidelberg/New York: Springer-Verlag, 1982. 16. Huang MH, 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. 17. McComb JG. Treatment of functional lambdoid synostosis. Neurosurg Clin N Am 1991; 2: 665-72. 18. Marchac D. Radical forehead remodeling for craniostenosis. Plast Reconstr Surg 1978; 61: 823-35.
377 19. Marchac D, Cophignon J, Hirsch JF, Renier D. Fronto-cranial remodeling for craniostenosis with mobilisation of the supraorbital barr [In French]. Neurochirurgie 1978; 24: 23-31. 20. 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. 21. Renier D, Sainte-Rose C, Marchac D. In Craniofacial Surgery. Marchac D, ed. Berlin/Heidelberg/New York: SpringerVerlag, 1985; 110-13. 22. Persing JA, Delashaw JB, Jane JA, Edgerton MT. Lambdoid synostosis: surgical considerations. Plast Reconstr Surg 1988; 81: 852-60. 23. Vander Kolk CA, Carson BS. Lambdoid synostosis. Clin Plast Surg 1994; 21: 575-84. 24. Kirby PJG, Beverley DW, Batchelor AG. Frequency of craniosynostosis in Yorkshire, UK. Lancet 1993; 341: 1412-13. 25. Menard RM, David DJ. Unilateral lambdoid synostosis: morphological characteristics. J Craniofac Surg 1998; 9: 240-6. 26. Becker LE, Hinton DR. Pathogenesis of craniosynostosis. Pediatr Neurosurg 1995; 22: 104-7. 27. Jones BM, Hayward R, Evans R, Britto J. Occipital plagiocephaly: an epidemic of craniosynostosis? BMJ 1997; 315: 693-4. 28. Laitinen L, Sulamoa M. Craniosynostosis: symptoms, treatment, and results of treatment. Ann Pediatr 1956; 2: 1. 29. Pople IK, Sanford RA, Muhlbauer MS. Clinical presentation and management of 100 infants with occipital plagiocephaly. Pediatr Neurosurg 1996; 25: l 6.
T h e Authors David J. David AC, MD, FRCS, FRACS Australian Craniofacial Unit, Women's and Children's Hospital, 72 King William Road, North Adelaide 5006, South Australia. R. M. Menard MD University of Adelaide, South Australia. Correspondence to Dr David J. David. Paper received 24 February 1999. Accepted 19 January 2000, after revision.
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Occipital plagiocephaly D. J. David and R. M. Menard*
Australian Craniofacial Unit, Women's and Children's Hospital, North Adelaide, South Australia and * University of Adelaide, South Australia SUMMARY. The diagnosis of occipital plagiocephaly has remained a complex and controversial issue in the field of craniofacial surgery. Over the past 30 years, numerous studies have been published describing the management and treatment for 'posterior plagiocephaly', 'plagiocephaly without synostosis', 'deformational plagiocephaly' and 'occipital plagiocephaly', with surgical 'correction' being chosen as the primary modality of treatment irrespective of the patency status of the lambdoid sutures. Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Each patient was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Only two of the 204 patients (- 1%) manifested the clinical, radiographic and pathological features of true unilambdoid synostosis. There was radiographic evidence of sutural fusion on plain films, 2-D and 3-D CT scans. Pathology specimens showed bony sutural fusion. Two hundred and two patients presented with unilateral occipital deformities and patent sutures on radiography. These patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (211204) included patients with severe plagiocephaly not responding to conservative therapy (191204) and the two patients with true unilambdoid synostosis (21204). One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement, one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. In our series it is apparent that the majority of cases of occipital plagiocephaly are not secondary to true synostosis and can be managed by conservative positional measures. 9 2000 The British Association of Plastic Surgeons Keywords: craniofacial surgery, occipital plagiocephaly, posterior plagiocephaly, conservative treatment, positional treatment, surgical correction, lambdoid synostosis.
The management of infants with occipital plagiocephaly has remained an area of controversy in the fields of paediatrics, neurosurgery and craniofacial surgery over the past 30 years. The deformity has been ascribed to a variety of extrinsic and intrinsic factors, including aberrant constraint of the foetal head in the intrauterine environment, ~ congenital muscular torticollis,24 preferential sleeping position in early infancy5,6 and secondary effects of cranial base abnormalities. 7 The initial asymmetry that may exist at birth is exacerbated by a persistent positional preference, with the infant resting its head on the flatter occipital surface. This in turn gives rise to the secondary cranial vault deformities, resulting in the 'parallelogram' head shape and asymmetrical ear position. There has been a wide and varied array of management strategies used on infants with occipital plagiocephaly, with treatment protocols based as much o n an individual's preference to operate as on objective factors. In certain studies, the initial management of infants with occipital plagiocephaly consisted of
lambdoid strip craniectomies 8,9 or posterior calvarial remodelling~~ despite radiographic and pathological evidence indicating patent lambdoid sutures. In the light of the non-synostotic nature of the overwhelming majority of the patients and the perceived need for an 'active' therapy, other studies have looked at normalising head shape through the use of an external orthosis. 4,6,12,13 Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Over that period of time a management protocol has been developed incorporating conservative positioning and physiotherapy treatment as the primary intervention in cases of non-synostotic occipital plagiocephaly; a treatment plan supported in recent literature. ~4 In those patients with severe plagiocephaly not responding to conservative therapy or with true unilambdoid synostosis, surgical correction was used towards normalising head shape. Where surgical correction was undertaken it was to release the fused suture to allow brain growth to influence the calvarial shape. 367
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C Figure 1--Unilambdoid synostosis.(A) AP plain film radiograph, right unilambdoid synostosis.Note 'copper beating' of right occipital region, right occipitomastoidbossing, right inferior skull base tilt, absent right lambdoid suture line, and facial asymmetry. (B) 2-D CT scan axial views infantwith right unilambdoid synostosis. Note patent left lambdoid suture and fused right lambdoid suture, with evidenceof occipital 'copper beating' and associated right occipitalflattening. (C) Posterior 3-D CT scan right unilambdoid synostosis.Fusion of the right lambdoid suture, prominent occipitomastoidbossing and right inferior tilt of the skull base is evident. The horizontal line denotes the levelof the axial 2-D CT image in Figure lB.
B Patients and methods
From January 1981 to July 1997, 204 children were referred to the Australian Craniofacial Unit, Adelaide, South Australia, for the evaluation and management of occipital plagiocephaly. The mean age of the infants at presentation was 6 months, with a range of 6 weeks to 24 months. The average current age o f patients in the series is 7 years. Each infant was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Clinical findings
and associated factors were documented, including age at presentation of deformity, birth history, history of torticollis or positional preference, history of developmental delay, severity of the deformity as seen clinically and radiologically, and ear position. All children were photographed at a minimum o f 1-year intervals. Patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (21/204) included patients with severe plagiocephaly not responding to conservative therapy (19/204) and two patients with true unilambdoid synostosis (2/204). Resected lambdoid suture specimens were evaluated histologically.
Results
O f the 204 patients with unilateral occipital deformities, only two patients (~ 1%) manifested the clinical, radiographic and pathological features of true lambdoid synostosis. Radiographically, there was evidence of sutural fusion on plain films, 2-D and 3-D CT scans (Fig. 1 A-C). Two hundred and two patients were noted to have patent lambdoid sutures on radiography
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Figure 2 Vertexview - deformational occipital plagiocephaly versus unilambdoid synostosis. (A) Infant with right-sided deformational occipital plagiocephaly. Note the right occipitoparietal flattening with prominent left occipital posterior bossing and right frontal bossing, resulting in a parallelogram head shape. (B) Infant with right unilambdoid synostosis. Note the prominent left parietal bossing with associated right occipitoparietal flattening, trapezoid head shape and right anterior ear displacement.
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Figure 2~-Posterior 3-D CT scan soft tissue view deformational occipital plagiocephaly versus unilambdoid synostosis. (A) Infant with right-sided deformational occipital plagiocephaly. (B) Infant with right unilambdoid synostosis. Note the horizontal posterior skull base in the infant with right-sided deformational occipital plagiocephaly; the infant with right unilambdoid synostosis displays a prominent occipitomastoid bulge, a compensatory twist of the cervical spine and a right inferior tilt of the skull base with inferior displacement of the right ear.
consistent w i t h d e f o r m a t i o n a l occipital plagiocephaly. These patients were g r o u p e d a c c o r d i n g to the severity o f their d e f o r m i t y as d e s c r i b e d by Clarren. 4 T h e r e were 84 patients with mild deformities (less t h a n 5 ~
difference), 90 with m o d e r a t e deformities (5-10 ~ difference) a n d 30 with severe deformities (greater t h a n 10 ~ difference). O n e h u n d r e d a n d t h i r t y - f o u r p a t i e n t s d i s p l a y e d a r i g h t - s i d e d occipital deformity, while there
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Figure4--Posterior 3-D CT scan bone view deformationaloccipitalplagiocephalyversus unilambdoidsynostosis.(A) Infant with right-sideddeformationaloccipitalplagiocephaly.(B) Infant with right unilambdoidsynostosis.Note the horizontalposterior skull base, visible bilateral lambdoidsutures and lack of parietal or occipitomastoidbossingin the infant with right-sideddeformationaloccipital plagiocephaly.In the infant with right unilambdoidsynostosis,fusion of the right lambdoidsuture, prominentoccipitomastoidbossingand right inferiortilt of the skull base are evident. were 70 left-sided deformities (65.7% right-sided versus 34.3% left-sided). Males outnumbered females 130 to 74 (64% male versus 36% female). A history of positional preference in infancy was seen in 48% of the patients (98/204), whereas torticollis was seen in 24% of the patients (49/204). Developmental delay was seen in 6% (12/204). Of the 202 patients with non-synostotic deformational occipital plagiocephaly, 19 were noted to have severe deformities that did not respond to head positioning and physiotherapy measures. These patients underwent occipital craniectomy with lambdoid suture resection at an average age of 7.6 months. All of these patients showed the apparent 'sclerosis' of the lambdoid suture, a sign that was given some significance at that time. A review of the histology showed that a patent suture was identifiable in each case. Only one of these patients was felt to be without notable improvement in cranial contour and symmetry as judged by their parents postoperatively. In addition to the radiological differences between the patients with true lambdoid synostosis and deformational occipital plagiocephaly, morphological differences were noted between them as well. Both deformational occipital plagiocephaly and unilambdoid synostosis patients presented with unilateral occipitoparietal flattening associated with contratateral posterior bossing. In the deformational patients, this posterior bossing was seen primarily in the occipital region, while in the synostotic patients it was seen more laterally and superiorly in the parietal region (Fig. 2A, B). In the two synostotic patients, a
prominent occipitomastoid bulge was present which was not seen in the deformational patients (Fig. 3A, B). In the two synostotic patients the posterior skull base was tilted inferiorly towards the affected side, with a compensatory twist in the cervical spine (Fig. 4). Secondary to the tilt in the posterior skull base, the ipsilateral ear was displaced inferiorly; when viewed from the vertex or from below, the two synostotic patients displayed anterior ear displacement, which is clearly demonstrated in the soft tissue 3-D CT images (Fig. 5). The patients with deformational occipital plagiocephaly displayed an essentially horizontal posterior skull base, with anterior ear displacement corresponding to the severity of their deformity (Fig. 4A, 5A). One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement performed on a patient presenting after infancy and one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. Discussion
In 1982, David et al published our results of patients with posterior (occipital) plagiocephaly; they constituted 9.6% of our series of simple synostoses. 15 We noted at the time that 'most of the cases classified as
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12 Figure 5--Basal 3-D CT scan soft tissue view deformational occipital plagiocephalyversus unilambdoid synostosis. (A) Infant with right-sided deformationaloccipitalplagiocephaly.Note the anterior ear displacementcorrespondingto the severityof the deformity,and lack of parietal or occipitomastoidbossing. (B, C) Two infants with right unilambdoid synostosis.Note moderate right anterior ear displacement,right occipitomastoidbulge, right occipital flatteningand left parietal prominence.
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unilambdoid synostosis fusions showed only sutural sclerosis without radiological evidence of fusion'. It was our view at the time, as it is now, that true lambdoid synostosis is a rare event. Much of the recent literature on the subject refers to the diagnosis and treatment of posterior plagiocephaly as being 'controversial'. 13'14'16'17What is the nature of this controversy and how has it come about?
Frequency In the current series the incidence of true lambdoid synostosis is very low (~ 1%). What has occurred is a
massive increase in the awareness of, reporting of and management of posterior (occipital) plagiocephaly. The 1970s saw the advancement of craniofacial surgery and, with it, the increasing concern of parents, family doctors, obstetricians and paediatricians, as well as neurosurgeons and cranio-facial surgeons. Early on, it was established that correction of synostosis of the coronal ring of sutures in frontal plagiocephaly due to synostosis of these sutures, when performed in the first few months of postnatal life, frequently gave long-lasting results and prevented disfiguring facial asynametry? s,18,~9The importance of making this early diagnosis raised the awareness first of the medical community and later of the general public of the importance of noting the skull shape in the neonate, since early appropriate intervention could prevent a permanent disfiguring craniofacial deformity. Paediatricians and orthopaedic surgeons have long recognised the association of torticollis and occipital plagiocephaly, and indeed made the association o f the deformity with external deformational forces. 4 The very significant papers by Muakkassa et al and Hinton et al 8,2~emanating from the Hospital for Sick Children in Toronto, presented the view that lambdoid 'synostosis' is different from other forms of synostosis, and that 'bone union (of isolated lambdoid synostosis sutures) was an unusual feature'. 2~ This paper was coupled with a review of cases from 1972 to 1982 reporting an incidence o f lambdoid synostosis of
372 18.5% and reporting that the results of linear craniectomy produced excellent or good results in the majority of patients. The implication at the end of the discussion that there may be some functional problems resulting from uncorrected single suture synostosis, as suggested by Renier et al 2~ (although without any particular reference to the lambdoid suture) added to the force of the argument for surgery. A summary of their position was that 'the condition is underdiagnosed; it can be diagnosed with proper awareness and state of the art radiological and nuclear medicine techniques; there are observable histological changes in the sutures; surgery produces 96% excellent or good result, and may save some patients having raised intracranial pressure.' We believe that these papers, coming as they did from such an excellent centre, had a very significant effect on the established neurosurgical and the emerging craniofacial surgical communities. Increased awareness, together with an increased tendency for correction of the skull deformity of posterior plagiocephaly by helmet moulding or by increasingly complex surgical manoeuvres 22,23resulted in more cases of posterior plagiocephaly being reported, with a greater proportion of these cases being ascribed to lambdoid synostosis and treated. In some cases the community saw this increase as an epidemic 24 that needed investigation and explanation. More recently, the 'back to sleep' campaign instituted in the USA in 1992 has been implicated, with the strict supine sleeping position suggested as.increasing the incidence of infants with deformation of the craniofacial skeleton. 5 The steady increase in the number of cases presenting to the Australian Craniofacial Unit support the view that this and similar campaigns have had an influence on the number of patients with deformed heads presenting for management.
Pathology In the rare cases of true lambdoid synostosis there was bony fusion across the lambdoid suture25 In this matter we agree with the recent publication by Huang et al. 16 The equivocal findings of variations, both at operation and radiologically, that give credibility to the special status of the lambdoid suture as one that may act in a 'sticky' fashion, may be explained by a casuistic zeal to justify surgical intervention, or by the possibility as suggested by Hinton et al 2~that some of these more subtle changes may be due to the increased stress of deformation early in the development of the suture. Save for the two cases of true lambdoid synostosis that we have described 25 and the patients described by Huang et a116 that differ markedly radiologically, morphologically and histologically from the majority of occipital plagiocephaly patients described, there was no evidence of complete bony fusion described in many of the operative cases of occipital plagiocephaly described in the literature2 ~
Clinical diagnosis Both deformational occipital plagiocephaly and unilambdoid synostosis patients presented with unilateral
British Journal of Plastic Surgery occipitoparietal flattening associated with contralateral posterior bossing; this contralateral bossing was primarily occipital in the deformational patients and parietal in the unilambdoid synostosis patients. The absence of any real orbital deformity or significant supraorbital depression clearly distinguishes the condition from frontal plagiocephaly. The diagnostic problem has been to distinguish deformational occipital plagiocephaly from unilambdoid synostosis, both clinically and radiologically. As we noted in 1982, the history may not be helpful, since the tendency to lie on one side could be the effect as well as the cause of the deformity. Prior to the article by Huang et a116 there had been no detailed anatomical description of the distinction between the diagnoses of unilambdoid synostosis and deformational plagiocephaly. This diagnostic problem was and is no light problem. In one case, early surgery on the posterior skull is sometimes required to prevent significant craniofacial deformity; in the other, with few or no exceptions, no surgical intervention is required and the natural history is one of relative self-correction. Confusion has led to many cases of unnecessary surgery and, indeed, some justified community anxiety resulting from this. 24,27 The findings of our study corroborate the findings of Huang et aP 6 with one important exception: the anteroinferior ear displacement seen on the side affected by unilambdoid synostosis. Both studies show the distinct features of unilambdoid synostosis versus deformational occipital plagiocephaly: 1. Contralateral posterior bossing occurring in the parietal region in patients with unilambdoid synostosis versus occipital bossing in patients with deformational occipital plagiocephaly. 2. Ipsilateral occipitomastoid bossing was seen in both patients with unilambdoid synostosis, but was absent in patients with deformational occipital plagiocephaly. 3. Ipsilateral inferior tilt of the posterior skull base was seen in patients with unilambdoid synostosis versus a horizontal skull base in deformational occipital plagiocephaly. 4. A trapezoid head shape as viewed from the vertex was seen in patients with unilambdoid synostosis versus a parallelogram head shape in deformational occipital plagiocephaly. With respect to ear position, there is an important difference between the anteroinferior ear displacement seen in our two cases and the posterior ear displacement as described by Huang et al? 6 The moderate anterior ear displacement seen in our cases can be explained by the pronounced occipitomastoid compensatory growth seen in the two patients with lambdoid synostosis, along the growth vector lines as described by Huang et al. ~6 In former, less discriminating times, others have also seen the anterior ear displacement in true lambdoid synostosis. 21 Extreme care should be exercised in making a diagnosis of unilambdoid synostosis - relying on single parameters such as ear position is superficially attractive, but in reality is an attempt to induce a general rule from a very small sample of true
Occipital plagiocephaly
Figure 6--2-D CT scan axial image, severe right deformational occipital plagiocephaly. Note prominent right inner table ridging, end-to-end suture pattern and associated right occipital flattening.
synostotic cases and, as is shown in this paper, soon falsified.
Radiological diagnos& In our series, all patients underwent plain radiographs of the skull. Both patients with lambdoid synostosis demonstrated 'copper beating' of the affected occipital region, with associated occipitomastoid bossing, inferior ipsilateral skull base tilt, absent suture line and secondary facial cant. 25 Two- and three-dimensional CT scans performed on these patients reiterated these findings. 25 Sutural fusion was seen on the 2-D CT slices and the 3-D CT reconstruction and clearly demonstrates the gross anatomy. Muakkassa and colleagues in 1984 rightly pointed out that the radiological features of lambdoid synostosis were at that stage not well documented) They went on to place great diagnostic importance on the presence of a sclerotic line along the superior or inferior edge of the lambdoid suture, stating that the suture may appear patent but functioned as if completely united. This diagnostic aid was taken up and treated as being of great significance. Our early surgical interventions on severe deformational cases were made on the basis of the association of this radiological sign with the deformation, using the causal proposition that such a suture would function in an abnormal way and therefore needed to be released. It is of interest to note that three of Muakkassa's 74 cases of lambdoid 'synostosis' demonstrated the local 'copper beaten' appearance. If we presume for argument's sake that this is a more reliable sign of lambdoid synostosis, then three cases out of 404 (~ 0.75%) rather than 74 of 404 (18.5%) is more in
373 line with the incidence of true lambdoid synostosis seen in this paper and that of Huang et al. 16 What then of the findings in axial CT scans showing an end-to-end suture pattern, associated with thickening of the inner cortex around the suture (Fig. 6)? Vander Kolk and Carson 23 clearly made this sign a feature of lambdoid synostosis, citing papers by Hinton et al, 2~ Laitinen and Sulamoa 28 and unpublished work by Cohen MM, in support of this view. Like Huang et all 6 we do not believe that this is a sign of sutural fusion; more likely, it is a response to the postural abnormality of deformational plagiocephaly. Pople et a129 proposed an interesting theory as to why patients with severe deformational plagiocephaly do not respond completely to conventional positioning measures. They suggested that the pronounced inner table ridging that is seen in patients with severe deformational occipital plagiocephaly results in a 'locked' lambdoid suture, causing the deformity to worsen. This theory has the elements of a more sophisticated restatement of the 'sticky' suture concept. These patients, however, should not be diagnosed as having unilambdoid synostosis because their cranial morphology differs markedly, as described, 16,25and their sutures are patent when examined histologically in Menard and DavidY
Treatment O f the 202 patients with deformational plagiocephaly, 19 (9.4%) underwent occipital craniectomy secondary to their severe deformity not responding to conservative management and being associated with the 'sclerotic' suture sign. There was the mistaken view that this combination of events represented sutural pathology, resulting in the deformity. All of these patients initially responded well to the surgery, yet they all remain with some residual deformity, even after many years (Fig. 7). This residual deformity is mostly covered by hair and of no cosmetic significance in all but two patients, in whom the deformity recurred relentlessly and persisted. Of those patients managed conservatively, that is with positioning and/or physiotherapy, the deformity is rarely if ever corrected completely (Fig. 8), but has never become a source of major concern. The facial deformity is rarely even perceptible and the residual occipital deformity, more readily seen on radiography, is hidden by the hair. The two patients with lambdoid synostosis treated by craniectomy in infancy have had their deformity corrected and this has been maintained with growth (Fig. 9). The use of helmet therapy for the management of the severe deformational patients has been described, 4,13but in the light of the natural history of all but a very few of these cases to improve to a level where the deformity is hardly noticeable, the question has to be asked whether even this degree of intervention is necessary or justified. Of the two severe cases of deformational plagiocephaly that underwent surgery and suffered progressive recurrent deformity we cannot shed any light to date on the particular aspects of the pathology and pathogenesis that are at work in these patients.
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Figure 7 Severe deformational occipital plagiocephaly with operative treatment (lambdoid craniectomy and posterior calvarial remodelling at 6 months of age), 8-year follow-up. (A) Vertex view, 6-month-old girl with severe right deformational occipital plagiocephaly, preoperative analysis. (B) Plain radiograph, basilar view, preoperative. Note the severe right occipital flattening and posterior contom irregularity. (C) Vertex view, 10 months old, 4 months postoperatively. Note the improved frontal contour with slight residual left frontal flattening. (D) Vertex view, 6 years old, 5 years and 6 months postoperatively. (E) Vertex view, 8 years and 6 months old, 8 years postoperatively. Note the adequate frontal contour, with the occipital contour concealed by hair growth.
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Figure 8 Moderate deformational occipital plagiocephaly with non-operative treatment, 6-year follow-up. (A) Vertex view, 8month-old girl with moderate right deformational occipital plagiocephaly. Note the right anterior ear displacement, left frontal flattening and right occipital flattening. (B) Plain radiograph, basilar view. Note the moderate right occipital flattening and posterior contour irregularity. Townes view revealed patent lambdoid sutures bilaterally. (C) Vertex view, 3 years and 8 months old. Note the improved frontal contour and occipital contour concealed by hair growth. (D) Vertex view, 6 years and 9 months old. (E) Plain radiograph, basilar view, 6 years and 9 months old. Note the improved posterior contour versus Figure 8B.
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Figure 9--True right unilambdoid synostosis with operative treatment (lambdoid craniectomy and posterior calvarial remodelling at 8 months of age), 5-year follow-up. (A) Vertex view, 8-month-old boy with right unilambdoid synostosis, preoperative analysis. Note the prominent left parietal bossing with associated right occipitoparietal flattening, trapezoid head shape and right anterior ear displacement. (B, C) AP and basilar plain films, preoperative. Note 'copper beating' of right occipital region, right occipitomastoid bossing, right inferior skull base tilt, absent right lambdoid suture line, and facial asymmetry. (D) Vertex view, 11 months old, 3 months post lambdoid craniectomy and posterior calvarial remodelling. (E) Vertex view, 6 years old, 5 years and 4 months post lambdoid craniectomy and posterior calvarial remodelling. Note the improved frontal contour and residual right anterior ear displacement. (F) Plain film, basilar view, 5 years and 4 months post lambdoid craniectomy and posterior calvarial remodelling.
Conclusion In the light of anatomical, radiological and histological studies m a d e over m a n y years, together with longterm follow-up of patients with occipital plagiocephaly, it can now be said that the morphological characteristics of patients with true unilambdoid synostosis differ significantly from those of patients with deformational occipital plagiocephaly. These findings include ipsilateral occipitomastoid bossing posterior ipsilateral skull tilt, contralateral parietal bossing and anteroinferior ear displacement. The diagnostic imaging and pathological findings are consistent with other forms of craniosynostosis, displaying bony sutural fusion.
Patients with occipital plagiocephaly should be carefully reviewed with clinical and diagnostic imaging examinations to describe the cranial m o r p h o l o g y accurately and assess the patency of the lambdoid sutures. Most cases of occipital plagiocephaly are secondary to deformational forces and will achieve satisfactory correction with conservative management. A few cases of nonsynostotic progressive deformity remain a mystery and warrant further close study. Progress in the understanding of the natural history and m a n a g e m e n t of occipital plagiocephaly has been an interesting one, with a retreat from surgical treatment in the deformational cases once the diagnostic criteria and natural history have been clarified.
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T h e Authors David J. David AC, MD, FRCS, FRACS Australian Craniofacial Unit, Women's and Children's Hospital, 72 King William Road, North Adelaide 5006, South Australia. R. M. Menard MD University of Adelaide, South Australia. Correspondence to Dr David J. David. Paper received 24 February 1999. Accepted 19 January 2000, after revision.