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Surgical correction of lambdoid synostosis – New technique and first results
Journal of Cranio-Maxillo-Facial Surgery xxx (2016) 1e5
Contents lists available at ScienceDirect
Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Surgical correction of lambdoid synostosis e New technique and first results* Jan-Falco Wilbrand a, *, Hans-Peter Howaldt a, Marcus Reinges b, Petros Christophis b a
University Hospital Giessen, Dept. for Cranio-Maxillofacial Surgery, Plastic Surgery (Head: Prof. Dr. Dr. H.P. Howaldt), Klinikstr. 33, 35385 Giessen, Germany b University Hospital Giessen, Dept. for Neurosurgery (Head: Prof. Dr. E. Uhl), Klinikstr. 33, 35385 Giessen, Germany
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 25 May 2016 Accepted 29 July 2016 Available online xxx
Objective: Premature craniosynostosis of the lambdoid suture is rare. The use of differential diagnosis to rule out positional occipital plagiocephaly is crucial. Nevertheless, once diagnosed, lambdoid craniosynostosis requires corrective surgery to prevent intracranial harm and aesthetic stigma by significant dyscrania. Operative correction of the lambdoid fusion is often performed by suturectomy and helmet therapy, total occipital remodeling interventions, transposition of occipital bone flaps, or occipital advancement procedures either with or without distraction osteogenesis. We present a simple surgical maneuver to potentially correct the occipital and suboccipital constriction caused by unilateral lambdoid craniosynostosis. Materials and methods: Three patients with true unilateral lambdoid synostosis underwent surgery. A straight-line skin incision was created, beginning at the caudal pole of the ipsilateral mastoideal bulge. The incision ran cranially and corresponded to the course of the lambdoid suture up to the posterior fontanel. The periosteum was incised and the contralateral (potent) lambdoid suture was identified at its origin. One burr-hole was created to separate the dura from the intern tabula. Afterwards, a square meander-shaped craniotomy was performed along the assumed course of the lambdoid suture. The squares were then forced apart to form the occipital and suboccipital area into a more rounded shape. The squares were fixed in those positions with resorbable plates or sutures. Pre- and postoperative threedimensional (3D) photoscans were performed and analyzed with special software to follow the perioperative course of the cranial shape. Results: This new approach minimized the operative time and degree of blood-loss, and rounding of the occipital area was accomplished with only one unilateral intervention. In terms of the available photogrammetric data of two of the patients, the cranial vault asymmetry index, posterior symmetry ratio, and posterior/anterior skull volume ratio were improved but not normalized completely. The measurement outcome, as determined by an automated analysis of the photoscans, however, indicated clear flaws with regard to repeatability. Conclusion: A unilateral approach using a square meander-shaped craniotomy and subsequent inclination may be a suitable surgical method for correcting assorted cases of lambdoid craniosynostosis. Transposition of the occipital bone flaps, subtotal craniectomies of the occipital area, and occipital advancements with or without distraction devices may not be essential in all cases of lambdoid synostosis. However, the reliability of the automated analysis of three-dimensional photoscans must be determined. © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Craniosynostosis Lambdoid synostosis Plagiocephaly Technical note
1. Introduction Abbreviations: CVAI, cranial vault asymmetry index; CI, cranial index; CVA, cranial vault asymmetry; OR, operation room; PAR, ratio of posterior/anterior skull volume (Q3 þ Q4)/(Q1 þ Q2); PSR, posterior symmetry ratio (Q3/Q4); ULS, unilateral lambdoid synostosis. * The authors have no grants, financial or other relevant relationships to declare. * Corresponding author. Fax: þ49 641 98546279. E-mail address: [email protected] (J.-F. Wilbrand).
Lambdoid craniosynostosis is a very rare condition with a prevalence of approximately one in every 40,000 births (David and Menard, 2000). Misdiagnosis is frequent (Cohen and MacLean, 2000) and is due mainly to the high frequency of positional occipital flattening following the “back-to-sleep-campaign”
http://dx.doi.org/10.1016/j.jcms.2016.07.031 1010-5182/© 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
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J.-F. Wilbrand et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2016) 1e5
begun in 1992 (AAP, 1992; Mawji et al., 2013; Turk et al., 1996). If true lambdoid synostosis is encountered, surgery is the only option for correcting intra- and extracranial constriction. Surgical methodology and timing varies. A recently published review of the surgical correction of unilateral lambdoid synostosis (ULS) systematically evaluated the available published data and found that the number of presented cases in the literature with true ULS was as low as 188 and that the surgical modus operandi was heterogeneous (Al-Jabri and Eccles, 2014). Additionally, the preoperative and follow-up diagnostic criteria regarding ULS were critically reviewed by the authors. David et al. defined four characteristic clinical patterns for ULS (David and Menard, 2000): mastoideal bulging, an ipsilateral inferior tilt of the skull base, a trapezoid head shape from the vertex view, and contralateral posterior parietal bossing. Furthermore, the occiput is shaped like a parallelogram when observed from behind (Fig. 1a, b) and the parietooccipital region shows a retraction perpendicular to the lambdoid suture running from the skull base over the inion towards the squamous suture. Surgical correction is not always able to adjust to every instance of asymmetry (Komuro et al., 2004; Smartt et al., 2007). This is particularly the case with regard to the cranio-caudal shift of the cranial base and the consecutive inferior positioning of the ipsilateral external auricular meatus and external ear. Jimenez and Barone et al. advocate endoscopic strip suturectomy and helmet therapy as the method of choice for lambdoid synostosis and report a short period of hospitalization and minimal blood loss (Jimenez et al., 2002; Johnson et al., 2000). Most other authors, however, tend to prefer open coronal approaches with bone-flap-remodeling or switching (Elliott et al., 2013; Liu et al., 2008; Persing et al., 1988; Sgouros et al., 1996), barrel-staving osteotomies (Jimenez and Barone, 1995), distraction osteogenesis (Komuro et al., 2004), or spring-assisted correction of the cranial deformity (Arnaud et al., 2012), among others. In this study, we present an endorsement of the common techniques used to correct ULS and provide objective anthropometric results collected pre- and postoperatively by examinerindependent photogrammetry (Wilbrand et al., 2012).
2. Materials and methods Children with ULS normally undergo surgery between the sixth and eighth month of life. We performed preoperative threedimensional (3D) computed tomography (CT) scanning to provide diagnostic certainty. Additionally, a 3D photogrammetric scan of the head was performed one day before the operation and approximately four weeks after. 2.1. Operative technique After removal of the hair, patients were placed in a 45 position contralateral to the synostosis. Following the additional application of a local anesthetic and the creation of a sterile environment, a straight-line skin incision was performed that ran from the onset of the nuchal musculature of the affected side upwards to the assumed position of the posterior fontanel (Fig. 2). An epiperiosteal dissection was made anteriorly and posteriorly and the origin of the contralateral and potent lambdoid suture was then identified (Fig. 3). The periosteum was incised downwards along the assumed course of the ipsilateral and synostosized lambdoid suture, from the origin of the contralateral lambdoid suture into the ipsilateral suboccipital region. Thereafter, a square meander-shaped craniotomy was performed over the entire course of the synostosized suture after releasing the dura from the tabula interna over a cranially and eventually caudally obtained burr-hole. Decompressing straight-line osteotomies were additionally obtained perpendicular to the vertex of the meander (Fig. 4). The craniotomized bone flaps were then forced apart, microfractured, and remodeled with Tessier forceps. Once a satisfactory rounding of the restricted area was obtained, the divided bone flaps were fixed in the distracted position with slowly resorbing suture osteosynthesis (Fig. 5) (Fearon, 2003). Finally, a drain was inserted and the skin wound closed in multilayers. Children undergoing this procedure received blood transfusions as a precaution, rather than to counteract complications arising from severe bleeding. Postoperatively, patients remained in the intensive care unit (ICU) overnight and were transferred to the
Fig. 1. (a): Clinical picture of ULS, parallelogram-shaped head deformity from posterior view in Child 2. (b): Typical head shape in lambdoid synostosis.
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
J.-F. Wilbrand et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2016) 1e5
3
neuropediatric ward thereafter. Adequate analgesia and perioperative antibiotics (cefotaxime) were administered by default. Patients were discharged from the neuropediatric ward as soon as the clinical course allowed. A second photoscan was routinely performed four weeks postoperatively. 2.2. Photogrammetric scan The Vectra (Canfield Scientific Inc., Fairfield, NJ, USA) 360 fourpod-system with Mirror software can obtain a 360 view of the infant's head within 3.5 ms. Cranioform Analytics® 4.0 software (Cranioform AG, Alpnach, Switzerland) was used to provide an examiner-independent analysis of the scan. This tool offers the option of objectively comparing pre- and postoperative photoscans, and evaluating distances, angles, volumes, and ratios (Wilbrand et al., 2012). With respect to this study, the posterior symmetry ratio (PSR) and the posterior-anterior skull volume ratio (PAR) were the crucial parameters. PSR opposes the left versus the right posterior skull volume, while PAR opposes total anterior versus total posterior skull volume. Furthermore, absolute measures of cranial asymmetry (CVA) as well as the cranial vault asymmetry index (CVAI), as defined by Loveday and de Chalain (2001), were analyzed by automated analysis.
Fig. 3. Presentation of the contralateral (potent) lambdoid suture at its origin.
3. Results 3.1. Operative results Three children (2 female, 1 male) with ULS underwent surgery with the above-described protocol in 2014. Complete datasets with photogrammetric scans taken pre- and postoperatively were obtained in two out of the three cases (66.6%). All children who underwent surgery by this technique presented a satisfying postoperative course and fast recovery. The mean operative time was 158 ± 33.9 min, and the volume of blood loss was approximately 150 mL per intervention. No complications occurred either intra- or postoperatively. The total ICU stay was one night, with drainage removed after 48 h. The total mean hospitalization time was four days. During the following outpatient clinical course,
Fig. 2. Skin incision placement.
irritation-free healing of the operative wound was monitored in all three patients. Parents reported no behavioral or psychomotor abnormalities after surgery. When the postoperative cranial shape was objectively assessed by both parents and the surgeon, an acceptable rounding of the prior existing occipital and suboccipital constriction was achieved in all cases. However, an improvement in the auricular position could not be obtained. Likewise, compensatory contralateral growth at the region of the uninvolved occiput, which was already present before the intervention, was also unable to be addressed by the surgical technique. No persistent bony defects were monitored after one postoperative year.
Fig. 4. Meander-shaped barrel-stave osteotomies.
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
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Fig. 5. Distracted bone flaps.
3.2. Results from the pre- and postoperative photoscans Photoscans were available for evaluation in two out of the three children. For the third child, fabrication of a preoperative photoscan was missed. Child 1 had right lambdoid synostosis and Child 2 had left lambdoid synostosis Fig. 1 (a). The preoperative PSR was 0.75 for Child 1 and 0.88 for Child 2 (a value of 1.0 would represent perfect symmetry); the PAR was 0.65 and 0.86, the CVA was 0.1 cm and 0.4 cm before surgery, and the preoperative 30 CVAI was 5.6 and 0.7, respectively. The photogrammetric scan performed at approximately 30 postoperative days showed a PSR of 0.69 and 0.78, for Child 1 and Child 2, respectively; PAR improved to 0.68 and 0.90, and the CVA remained at 0.4 cm in the second child and changed to 0.3 cm in the first child. The postoperative 30 CVAI increased to 6.2 and 4.0 in the first and second child, respectively, after intervention (Table 1). The respective cranial volume in the operated region (right occiput in Child 1 and left occiput in Child 2) showed a higher volume gain than all other regions. With regard to the photogrammetric analysis of the scans, the index of cranial asymmetry was found to have worsened after surgery. Given this finding, repeated measurements were performed for both pre- and postoperative photoscans of the two patients. The results, to our regret, were not repeatable using the Cranioform Analytics® software.
4. Discussion Surgical pathways for correcting the rare clinical condition of ULS vary. While some authors advocate minimally invasive procedures potentially accompanied by orthotic therapy (Jimenez et al., 2002), others promote advances in distraction osteogenesis (Arnaud et al., 2012) or full remodeling operations (Smartt et al., 2007). Wagner et al. from Mainz in 2010 and Schulz et al. from Berlin in 2014 presented a “meander-shaped craniotomy” to correct (not only synostotic) posterior plagiocephaly, brachycephaly, or a “mercedes-benz-pattern”-craniosynostosis (Moore et al., 1998; Schulz et al., 2014; Wagner et al., 2010). The Berlin-based study included four patients with true ULS; two other patients had
positional plagiocephaly, five showed synostotic-, and one showed non-synostotic brachycephaly. The technique presented here was based on a paper by Wagner et al. (2010) from 2010. Both approaches required relatively wide surgical access via the open coronal approach. The craniotomies extended across the entire occiput either in a vertical (Wagner et al., 2010) or horizontal manner (Schulz et al., 2014) and, after remodeling of the occipital constraint, the bone flaps were locked in the corrected position with resorbable sutures or plates. A similar operative technique was utilized in our clinic at this time. However, we required a much smaller surgical access created by a straight-line upward-running skin incision (Fig. 3) and used limited craniotomies with barrelstave osteotomies at the vertex region of the meanders (Fig. 4). Schulz et al. were able to measurably improve the cranial Index in brachycephalic children (Schulz et al., 2014). The improvement of asymmetry in ULS, however, could only be indicated as subjectively “improved” in their paper. With 3D photogrammetry, a relatively new tool is available in craniofacial surgery (Schaaf et al., 2008; Wong et al., 2008). The main reasons for the surgical correction of ULS are to reduce potentially elevated intracranial pressure and dissolve the cerebral constraints, as well as improve and normalize significantly deformed cranial shapes (Schulz et al., 2014). ULS is encountered along with Chiari malformation (CM) in up to 55% of cases (Strahle et al., 2011). Although CM potentially can have functional impact and is frequently seen especially in syndromic craniosynostoses (Rijken et al., 2015), changes of this condition caused by our procedure was not evaluated. Normalization of the cranial shape, however, can be objectified only by the existence of normative craniofacial percentiles (Wilbrand et al., 2014) and the option to control changes in head shape independent of intra- or inter-examiner failure and free of influence by subjective evaluation standards (Wilbrand et al., 2012). Perioperative changes to the cranial shape and symmetry in ULS treated with the above-mentioned operative technique were evaluated for the first time in this study by 3D photogrammetry. Although the number of patients presented here is low, the results from this study show that perfect cranial symmetry could not be obtained completely for patients treated with our surgical protocol. Additionally, for the photogrammetric scans evaluated here, it was found that repetition of the automated measurements of the 3D surface by the Cranioform Analytics® software did not necessarily lead to equivalent measurement outcomes. While cranial symmetry worsened between the pre- and postoperative scans on the first analysis, it improved during the next analysis. The analyses were performed by an experienced examiner (jfw) using the same locations for the following anthropometric points: nasion (n), subnasale (sn), tragus (tr) right and left, eurion (eu) right and left, lateral commissure (eye) right and left, lip, and pogonin (chin). The overall volume of the head surface scan was comparable and fluctuated within 25 cc (with an overall volume of approximately 1500 cc). The individual photogrammetric measurements, however, appear to show some degree of imprecision. Subsequently, further studies are now being implemented to more closely
Table 1 Pre- and postoperative measurements obtained by automated analysis of 3D-photoscans (PSR ¼ posterior symmetry ratio, PAR ¼ ratio of posterior/anterior skull volume, CVA ¼ cranial vault asymmetry, CVAI ¼ cranial vault asymmetry index as defined by Loveday and DeChalain (2001). PSR
Child 1 Child 2
PAR
CVA
CVAI
Pre
Post
Pre
Post
Pre
Post
Pre
Post
0.75 0.88
0.69 0.78
0.65 0.86
0.68 0.90
0.1 0.4
0.3 0.4
5.6 0.7
6.2 4.0
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
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evaluate the accuracy and repeatability of the automated analysis of 3D photogrammetric scans. Validation of such inaccuracies would have a significant clinical impact on the explanatory power of various studies (Freudlsperger et al., 2015; Krimmel et al., 2015; Wilbrand et al., 2012). The lack of repeatability of our photogrammetric analyses once again leaves us with subjective evaluation standards and simple anthropometric caliper measurements. In terms of a subjective appraisal of the postoperative outcome after the correction of ULS, we can report a consistent positive assessment by both parents and practitioners. Nevertheless, since complete correction of the asymmetry and auricular dislocation, as well as cranio-caudal shifting of the skull base, was incomplete, we must rate our results as Whitaker II (Whitaker et al., 1987), at best. We found a clear improvement in cranial symmetry and normal growth after surgery using anthropometric measurements made with sliding calipers and a measuring tape following the standard protocol (Wilbrand et al., 2011). These measurements were one dimensional, a limitation for complex cranial deformation caused by suboccipital constraint in lambdoid craniosynostosis. Overall, perioperative complications, length of hospitalization, and surgical effort are clearly reduced by the meander-shaped craniotomy technique via straight-line incision for the correction of assorted cases of ULS. 5. Conclusion Straight-line incision combined with meander-shaped osteotomies perpendicular to the synostosized lambdoid suture leads to, at least subjectively, identifiable correction of the cranial deformation in the correction of true ULS. The automated analysis of photogrammetric scans requires clear evaluation regarding the reliability and repeatability of craniofacial measurements. References AAP: American academy of pediatrics AAP task force on infant positioning and SIDS: positioning and SIDS. Pediatrics 89: 1120e1126, 1992 Al-Jabri T, Eccles S: Surgical correction for unilateral lambdoid synostosis: a systematic review. J Craniofac Surg 25: 1266e1272, 2014 Arnaud E, Marchac A, Jeblaoui Y, Renier D, Di Rocco F: Spring-assisted posterior skull expansion without osteotomies. Childs Nerv Syst 28: 1545e1549, 2012 Cohen Jr MM, MacLean RE. Craniosynostostis - Diagnosis, Evaluation, and Management., Vol. 2. New York Oxford: Oxford University Press, 2000 David DJ, Menard RM: Occipital plagiocephaly. Br J Plast Surg 53: 367e377, 2000 Elliott RM, Smartt Jr JM, Taylor JA, Bartlett SP: Does conventional posterior vault remodeling alter endocranial morphology in patients with true lambdoid synostosis? J Craniofac Surg 24: 115e119, 2013 Fearon JA: Rigid fixation of the calvaria in craniosynostosis without using “rigid” fixation. Plast Reconstr Surg 111: 27e38, 2003 [discussion 39] Freudlsperger C, Steinmacher S, Bachli H, Somlo E, Hoffmann J, Engel M: Metopic synostosis: measuring intracranial volume change following fronto-orbital advancement using three-dimensional photogrammetry. J Craniomaxillofac Surg 43: 593e598, 2015
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Jimenez DF, Barone CM: The Sunrise Technique: the correction of occipital plagiocephaly using bandeau occipital plate and radial osteotomies. Pediatr Neurosurg 22: 162e165, 1995 [discussion 166] Jimenez DF, Barone CM, Cartwright CC, Baker L: Early management of craniosynostosis using endoscopic-assisted strip craniectomies and cranial orthotic molding therapy. Pediatrics 110: 97e104, 2002 Johnson JO, Jimenez DF, Barone CM: Blood loss after endoscopic strip craniectomy for craniosynostosis. J Neurosurg Anesthesiol 12: 60, 2000 Komuro Y, Yanai A, Hayashi A, Miyajima M, Nakanishi H, Arai H: Treatment of unilateral lambdoid synostosis with cranial distraction. J Craniofac Surg 15: 609e613, 2004 Krimmel M, Breidt M, Bacher M, Müller-Hagedorn S, Dietz K, Bülthoff H, et al: Three-dimensional normal facial growth from birth to the age of 7 years. Plast Reconstr Surg 136: 490ee501e, 2015 Liu Y, Kadlub N, da Silva Freitas R, Persing JA, Duncan C, Shin JH: The misdiagnosis of craniosynostosis as deformational plagiocephaly. J Craniofac Surg 19: 132e136, 2008 Loveday BP, de Chalain TB: Active counterpositioning or orthotic device to treat positional plagiocephaly? J Craniofac Surg 12: 308e313, 2001 Mawji A, Vollman AR, Hatfield J, McNeil DA, Sauve R: The incidence of positional plagiocephaly: a cohort study. Pediatrics 132: 298e304, 2013 Moore MH, Abbott AH, Netherway DJ, Menard R, Hanieh A: Bilambdoid and posterior sagittal synostosis: the Mercedes Benz syndrome. J Craniofac Surg 9: 417e422, 1998 Persing JA, Delashaw JB, Jane JA, Edgerton MT: Lambdoid synostosis: surgical considerations. Plast Reconstr Surg 81: 852e860, 1988 Rijken BF, Lequin MH, Van Veelen ML, de Rooi J, Mathijssen IM: The formation of the foramen magnum and its role in developing ventriculomegaly and Chiari I malformation in children with craniosynostosis syndromes. J Craniomaxillofac Surg 43: 1042e1048, 2015 Schaaf H, Wilbrand JF, Howaldt HP: O.089 3D cephalometry of cranial deformities using 3dMD camera. J Craniomaxillofac Surg 36, 2008 S23eS23 Schulz M, Spors B, Haberl H, Thomale UW: Results of posterior cranial vault remodeling for plagiocephaly and brachycephaly by the meander technique. Childs Nerv Syst 30: 1517e1526, 2014 Sgouros S, Goldin JH, Hockley AD, Wake MJ: Posterior skull surgery in craniosynostosis. Childs Nerv Syst 12: 727e733, 1996 Smartt Jr JM, Reid RR, Singh DJ, Bartlett SP: True lambdoid craniosynostosis: longterm results of surgical and conservative therapy. Plast Reconstr Surg 120: 993e1003, 2007 Strahle J, Muraszko KM, Buchman SR, Kapurch J, Garton HJ, Maher CO: Chiari malformation associated with craniosynostosis. Neurosurg Focus 31: E2, 2011 Turk AE, McCarthy JG, Thorne CH, Wisoff JH: The “back to sleep campaign” and deformational plagiocephaly: is there cause for concern? J Craniofac Surg 7: 12e18, 1996 Wagner W, Schwandt E, Huthmann A, Vulcu S, Tschan C: Posterior calvarial augmentation in premature craniosynostosis: a technique avoiding foreign implants or free bone flaps. Childs Nerv Syst 26: 1549e1553, 2010 Whitaker LA, Bartlett SP, Schut L, Bruce D: Craniosynostosis: an analysis of the timing, treatment, and complications in 164 consecutive patients. Plast Reconstr Surg 80: 195e212, 1987 Wilbrand JF, Wilbrand M, Pons-Kuehnemann J, Blecher JC, Christophis P, Howaldt HP, et al: Value and reliability of anthropometric measurements of cranial deformity in early childhood. J Craniomaxillofac Surg 39: 24e29, 2011 Wilbrand JF, Szczukowski A, Blecher JC, Pons-Kuehnemann J, Christophis P, Howaldt HP, et al: Objectification of cranial vault correction for craniosynostosis by three-dimensional photography. J Craniomaxillofac Surg 40: 726e730, 2012 Wilbrand JF, Bierther U, Nord T, Reinges M, Hahn A, Christophis P, et al: Percentilebased assessment of craniosynostosis. J Craniomaxillofac Surg 42: 634e640, 2014 Wong JY, Oh AK, Ohta E, Hunt AT, Rogers GF, Mulliken JB, et al: Validity and reliability of craniofacial anthropometric measurement of 3D digital photogrammetric images. Cleft Palate Craniofac J 45: 232e239, 2008
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
Contents lists available at ScienceDirect
Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Surgical correction of lambdoid synostosis e New technique and first results* Jan-Falco Wilbrand a, *, Hans-Peter Howaldt a, Marcus Reinges b, Petros Christophis b a
University Hospital Giessen, Dept. for Cranio-Maxillofacial Surgery, Plastic Surgery (Head: Prof. Dr. Dr. H.P. Howaldt), Klinikstr. 33, 35385 Giessen, Germany b University Hospital Giessen, Dept. for Neurosurgery (Head: Prof. Dr. E. Uhl), Klinikstr. 33, 35385 Giessen, Germany
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 25 May 2016 Accepted 29 July 2016 Available online xxx
Objective: Premature craniosynostosis of the lambdoid suture is rare. The use of differential diagnosis to rule out positional occipital plagiocephaly is crucial. Nevertheless, once diagnosed, lambdoid craniosynostosis requires corrective surgery to prevent intracranial harm and aesthetic stigma by significant dyscrania. Operative correction of the lambdoid fusion is often performed by suturectomy and helmet therapy, total occipital remodeling interventions, transposition of occipital bone flaps, or occipital advancement procedures either with or without distraction osteogenesis. We present a simple surgical maneuver to potentially correct the occipital and suboccipital constriction caused by unilateral lambdoid craniosynostosis. Materials and methods: Three patients with true unilateral lambdoid synostosis underwent surgery. A straight-line skin incision was created, beginning at the caudal pole of the ipsilateral mastoideal bulge. The incision ran cranially and corresponded to the course of the lambdoid suture up to the posterior fontanel. The periosteum was incised and the contralateral (potent) lambdoid suture was identified at its origin. One burr-hole was created to separate the dura from the intern tabula. Afterwards, a square meander-shaped craniotomy was performed along the assumed course of the lambdoid suture. The squares were then forced apart to form the occipital and suboccipital area into a more rounded shape. The squares were fixed in those positions with resorbable plates or sutures. Pre- and postoperative threedimensional (3D) photoscans were performed and analyzed with special software to follow the perioperative course of the cranial shape. Results: This new approach minimized the operative time and degree of blood-loss, and rounding of the occipital area was accomplished with only one unilateral intervention. In terms of the available photogrammetric data of two of the patients, the cranial vault asymmetry index, posterior symmetry ratio, and posterior/anterior skull volume ratio were improved but not normalized completely. The measurement outcome, as determined by an automated analysis of the photoscans, however, indicated clear flaws with regard to repeatability. Conclusion: A unilateral approach using a square meander-shaped craniotomy and subsequent inclination may be a suitable surgical method for correcting assorted cases of lambdoid craniosynostosis. Transposition of the occipital bone flaps, subtotal craniectomies of the occipital area, and occipital advancements with or without distraction devices may not be essential in all cases of lambdoid synostosis. However, the reliability of the automated analysis of three-dimensional photoscans must be determined. © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Craniosynostosis Lambdoid synostosis Plagiocephaly Technical note
1. Introduction Abbreviations: CVAI, cranial vault asymmetry index; CI, cranial index; CVA, cranial vault asymmetry; OR, operation room; PAR, ratio of posterior/anterior skull volume (Q3 þ Q4)/(Q1 þ Q2); PSR, posterior symmetry ratio (Q3/Q4); ULS, unilateral lambdoid synostosis. * The authors have no grants, financial or other relevant relationships to declare. * Corresponding author. Fax: þ49 641 98546279. E-mail address: [email protected] (J.-F. Wilbrand).
Lambdoid craniosynostosis is a very rare condition with a prevalence of approximately one in every 40,000 births (David and Menard, 2000). Misdiagnosis is frequent (Cohen and MacLean, 2000) and is due mainly to the high frequency of positional occipital flattening following the “back-to-sleep-campaign”
http://dx.doi.org/10.1016/j.jcms.2016.07.031 1010-5182/© 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
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begun in 1992 (AAP, 1992; Mawji et al., 2013; Turk et al., 1996). If true lambdoid synostosis is encountered, surgery is the only option for correcting intra- and extracranial constriction. Surgical methodology and timing varies. A recently published review of the surgical correction of unilateral lambdoid synostosis (ULS) systematically evaluated the available published data and found that the number of presented cases in the literature with true ULS was as low as 188 and that the surgical modus operandi was heterogeneous (Al-Jabri and Eccles, 2014). Additionally, the preoperative and follow-up diagnostic criteria regarding ULS were critically reviewed by the authors. David et al. defined four characteristic clinical patterns for ULS (David and Menard, 2000): mastoideal bulging, an ipsilateral inferior tilt of the skull base, a trapezoid head shape from the vertex view, and contralateral posterior parietal bossing. Furthermore, the occiput is shaped like a parallelogram when observed from behind (Fig. 1a, b) and the parietooccipital region shows a retraction perpendicular to the lambdoid suture running from the skull base over the inion towards the squamous suture. Surgical correction is not always able to adjust to every instance of asymmetry (Komuro et al., 2004; Smartt et al., 2007). This is particularly the case with regard to the cranio-caudal shift of the cranial base and the consecutive inferior positioning of the ipsilateral external auricular meatus and external ear. Jimenez and Barone et al. advocate endoscopic strip suturectomy and helmet therapy as the method of choice for lambdoid synostosis and report a short period of hospitalization and minimal blood loss (Jimenez et al., 2002; Johnson et al., 2000). Most other authors, however, tend to prefer open coronal approaches with bone-flap-remodeling or switching (Elliott et al., 2013; Liu et al., 2008; Persing et al., 1988; Sgouros et al., 1996), barrel-staving osteotomies (Jimenez and Barone, 1995), distraction osteogenesis (Komuro et al., 2004), or spring-assisted correction of the cranial deformity (Arnaud et al., 2012), among others. In this study, we present an endorsement of the common techniques used to correct ULS and provide objective anthropometric results collected pre- and postoperatively by examinerindependent photogrammetry (Wilbrand et al., 2012).
2. Materials and methods Children with ULS normally undergo surgery between the sixth and eighth month of life. We performed preoperative threedimensional (3D) computed tomography (CT) scanning to provide diagnostic certainty. Additionally, a 3D photogrammetric scan of the head was performed one day before the operation and approximately four weeks after. 2.1. Operative technique After removal of the hair, patients were placed in a 45 position contralateral to the synostosis. Following the additional application of a local anesthetic and the creation of a sterile environment, a straight-line skin incision was performed that ran from the onset of the nuchal musculature of the affected side upwards to the assumed position of the posterior fontanel (Fig. 2). An epiperiosteal dissection was made anteriorly and posteriorly and the origin of the contralateral and potent lambdoid suture was then identified (Fig. 3). The periosteum was incised downwards along the assumed course of the ipsilateral and synostosized lambdoid suture, from the origin of the contralateral lambdoid suture into the ipsilateral suboccipital region. Thereafter, a square meander-shaped craniotomy was performed over the entire course of the synostosized suture after releasing the dura from the tabula interna over a cranially and eventually caudally obtained burr-hole. Decompressing straight-line osteotomies were additionally obtained perpendicular to the vertex of the meander (Fig. 4). The craniotomized bone flaps were then forced apart, microfractured, and remodeled with Tessier forceps. Once a satisfactory rounding of the restricted area was obtained, the divided bone flaps were fixed in the distracted position with slowly resorbing suture osteosynthesis (Fig. 5) (Fearon, 2003). Finally, a drain was inserted and the skin wound closed in multilayers. Children undergoing this procedure received blood transfusions as a precaution, rather than to counteract complications arising from severe bleeding. Postoperatively, patients remained in the intensive care unit (ICU) overnight and were transferred to the
Fig. 1. (a): Clinical picture of ULS, parallelogram-shaped head deformity from posterior view in Child 2. (b): Typical head shape in lambdoid synostosis.
Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031
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neuropediatric ward thereafter. Adequate analgesia and perioperative antibiotics (cefotaxime) were administered by default. Patients were discharged from the neuropediatric ward as soon as the clinical course allowed. A second photoscan was routinely performed four weeks postoperatively. 2.2. Photogrammetric scan The Vectra (Canfield Scientific Inc., Fairfield, NJ, USA) 360 fourpod-system with Mirror software can obtain a 360 view of the infant's head within 3.5 ms. Cranioform Analytics® 4.0 software (Cranioform AG, Alpnach, Switzerland) was used to provide an examiner-independent analysis of the scan. This tool offers the option of objectively comparing pre- and postoperative photoscans, and evaluating distances, angles, volumes, and ratios (Wilbrand et al., 2012). With respect to this study, the posterior symmetry ratio (PSR) and the posterior-anterior skull volume ratio (PAR) were the crucial parameters. PSR opposes the left versus the right posterior skull volume, while PAR opposes total anterior versus total posterior skull volume. Furthermore, absolute measures of cranial asymmetry (CVA) as well as the cranial vault asymmetry index (CVAI), as defined by Loveday and de Chalain (2001), were analyzed by automated analysis.
Fig. 3. Presentation of the contralateral (potent) lambdoid suture at its origin.
3. Results 3.1. Operative results Three children (2 female, 1 male) with ULS underwent surgery with the above-described protocol in 2014. Complete datasets with photogrammetric scans taken pre- and postoperatively were obtained in two out of the three cases (66.6%). All children who underwent surgery by this technique presented a satisfying postoperative course and fast recovery. The mean operative time was 158 ± 33.9 min, and the volume of blood loss was approximately 150 mL per intervention. No complications occurred either intra- or postoperatively. The total ICU stay was one night, with drainage removed after 48 h. The total mean hospitalization time was four days. During the following outpatient clinical course,
Fig. 2. Skin incision placement.
irritation-free healing of the operative wound was monitored in all three patients. Parents reported no behavioral or psychomotor abnormalities after surgery. When the postoperative cranial shape was objectively assessed by both parents and the surgeon, an acceptable rounding of the prior existing occipital and suboccipital constriction was achieved in all cases. However, an improvement in the auricular position could not be obtained. Likewise, compensatory contralateral growth at the region of the uninvolved occiput, which was already present before the intervention, was also unable to be addressed by the surgical technique. No persistent bony defects were monitored after one postoperative year.
Fig. 4. Meander-shaped barrel-stave osteotomies.
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Fig. 5. Distracted bone flaps.
3.2. Results from the pre- and postoperative photoscans Photoscans were available for evaluation in two out of the three children. For the third child, fabrication of a preoperative photoscan was missed. Child 1 had right lambdoid synostosis and Child 2 had left lambdoid synostosis Fig. 1 (a). The preoperative PSR was 0.75 for Child 1 and 0.88 for Child 2 (a value of 1.0 would represent perfect symmetry); the PAR was 0.65 and 0.86, the CVA was 0.1 cm and 0.4 cm before surgery, and the preoperative 30 CVAI was 5.6 and 0.7, respectively. The photogrammetric scan performed at approximately 30 postoperative days showed a PSR of 0.69 and 0.78, for Child 1 and Child 2, respectively; PAR improved to 0.68 and 0.90, and the CVA remained at 0.4 cm in the second child and changed to 0.3 cm in the first child. The postoperative 30 CVAI increased to 6.2 and 4.0 in the first and second child, respectively, after intervention (Table 1). The respective cranial volume in the operated region (right occiput in Child 1 and left occiput in Child 2) showed a higher volume gain than all other regions. With regard to the photogrammetric analysis of the scans, the index of cranial asymmetry was found to have worsened after surgery. Given this finding, repeated measurements were performed for both pre- and postoperative photoscans of the two patients. The results, to our regret, were not repeatable using the Cranioform Analytics® software.
4. Discussion Surgical pathways for correcting the rare clinical condition of ULS vary. While some authors advocate minimally invasive procedures potentially accompanied by orthotic therapy (Jimenez et al., 2002), others promote advances in distraction osteogenesis (Arnaud et al., 2012) or full remodeling operations (Smartt et al., 2007). Wagner et al. from Mainz in 2010 and Schulz et al. from Berlin in 2014 presented a “meander-shaped craniotomy” to correct (not only synostotic) posterior plagiocephaly, brachycephaly, or a “mercedes-benz-pattern”-craniosynostosis (Moore et al., 1998; Schulz et al., 2014; Wagner et al., 2010). The Berlin-based study included four patients with true ULS; two other patients had
positional plagiocephaly, five showed synostotic-, and one showed non-synostotic brachycephaly. The technique presented here was based on a paper by Wagner et al. (2010) from 2010. Both approaches required relatively wide surgical access via the open coronal approach. The craniotomies extended across the entire occiput either in a vertical (Wagner et al., 2010) or horizontal manner (Schulz et al., 2014) and, after remodeling of the occipital constraint, the bone flaps were locked in the corrected position with resorbable sutures or plates. A similar operative technique was utilized in our clinic at this time. However, we required a much smaller surgical access created by a straight-line upward-running skin incision (Fig. 3) and used limited craniotomies with barrelstave osteotomies at the vertex region of the meanders (Fig. 4). Schulz et al. were able to measurably improve the cranial Index in brachycephalic children (Schulz et al., 2014). The improvement of asymmetry in ULS, however, could only be indicated as subjectively “improved” in their paper. With 3D photogrammetry, a relatively new tool is available in craniofacial surgery (Schaaf et al., 2008; Wong et al., 2008). The main reasons for the surgical correction of ULS are to reduce potentially elevated intracranial pressure and dissolve the cerebral constraints, as well as improve and normalize significantly deformed cranial shapes (Schulz et al., 2014). ULS is encountered along with Chiari malformation (CM) in up to 55% of cases (Strahle et al., 2011). Although CM potentially can have functional impact and is frequently seen especially in syndromic craniosynostoses (Rijken et al., 2015), changes of this condition caused by our procedure was not evaluated. Normalization of the cranial shape, however, can be objectified only by the existence of normative craniofacial percentiles (Wilbrand et al., 2014) and the option to control changes in head shape independent of intra- or inter-examiner failure and free of influence by subjective evaluation standards (Wilbrand et al., 2012). Perioperative changes to the cranial shape and symmetry in ULS treated with the above-mentioned operative technique were evaluated for the first time in this study by 3D photogrammetry. Although the number of patients presented here is low, the results from this study show that perfect cranial symmetry could not be obtained completely for patients treated with our surgical protocol. Additionally, for the photogrammetric scans evaluated here, it was found that repetition of the automated measurements of the 3D surface by the Cranioform Analytics® software did not necessarily lead to equivalent measurement outcomes. While cranial symmetry worsened between the pre- and postoperative scans on the first analysis, it improved during the next analysis. The analyses were performed by an experienced examiner (jfw) using the same locations for the following anthropometric points: nasion (n), subnasale (sn), tragus (tr) right and left, eurion (eu) right and left, lateral commissure (eye) right and left, lip, and pogonin (chin). The overall volume of the head surface scan was comparable and fluctuated within 25 cc (with an overall volume of approximately 1500 cc). The individual photogrammetric measurements, however, appear to show some degree of imprecision. Subsequently, further studies are now being implemented to more closely
Table 1 Pre- and postoperative measurements obtained by automated analysis of 3D-photoscans (PSR ¼ posterior symmetry ratio, PAR ¼ ratio of posterior/anterior skull volume, CVA ¼ cranial vault asymmetry, CVAI ¼ cranial vault asymmetry index as defined by Loveday and DeChalain (2001). PSR
Child 1 Child 2
PAR
CVA
CVAI
Pre
Post
Pre
Post
Pre
Post
Pre
Post
0.75 0.88
0.69 0.78
0.65 0.86
0.68 0.90
0.1 0.4
0.3 0.4
5.6 0.7
6.2 4.0
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evaluate the accuracy and repeatability of the automated analysis of 3D photogrammetric scans. Validation of such inaccuracies would have a significant clinical impact on the explanatory power of various studies (Freudlsperger et al., 2015; Krimmel et al., 2015; Wilbrand et al., 2012). The lack of repeatability of our photogrammetric analyses once again leaves us with subjective evaluation standards and simple anthropometric caliper measurements. In terms of a subjective appraisal of the postoperative outcome after the correction of ULS, we can report a consistent positive assessment by both parents and practitioners. Nevertheless, since complete correction of the asymmetry and auricular dislocation, as well as cranio-caudal shifting of the skull base, was incomplete, we must rate our results as Whitaker II (Whitaker et al., 1987), at best. We found a clear improvement in cranial symmetry and normal growth after surgery using anthropometric measurements made with sliding calipers and a measuring tape following the standard protocol (Wilbrand et al., 2011). These measurements were one dimensional, a limitation for complex cranial deformation caused by suboccipital constraint in lambdoid craniosynostosis. Overall, perioperative complications, length of hospitalization, and surgical effort are clearly reduced by the meander-shaped craniotomy technique via straight-line incision for the correction of assorted cases of ULS. 5. Conclusion Straight-line incision combined with meander-shaped osteotomies perpendicular to the synostosized lambdoid suture leads to, at least subjectively, identifiable correction of the cranial deformation in the correction of true ULS. The automated analysis of photogrammetric scans requires clear evaluation regarding the reliability and repeatability of craniofacial measurements. References AAP: American academy of pediatrics AAP task force on infant positioning and SIDS: positioning and SIDS. Pediatrics 89: 1120e1126, 1992 Al-Jabri T, Eccles S: Surgical correction for unilateral lambdoid synostosis: a systematic review. J Craniofac Surg 25: 1266e1272, 2014 Arnaud E, Marchac A, Jeblaoui Y, Renier D, Di Rocco F: Spring-assisted posterior skull expansion without osteotomies. Childs Nerv Syst 28: 1545e1549, 2012 Cohen Jr MM, MacLean RE. Craniosynostostis - Diagnosis, Evaluation, and Management., Vol. 2. New York Oxford: Oxford University Press, 2000 David DJ, Menard RM: Occipital plagiocephaly. Br J Plast Surg 53: 367e377, 2000 Elliott RM, Smartt Jr JM, Taylor JA, Bartlett SP: Does conventional posterior vault remodeling alter endocranial morphology in patients with true lambdoid synostosis? J Craniofac Surg 24: 115e119, 2013 Fearon JA: Rigid fixation of the calvaria in craniosynostosis without using “rigid” fixation. Plast Reconstr Surg 111: 27e38, 2003 [discussion 39] Freudlsperger C, Steinmacher S, Bachli H, Somlo E, Hoffmann J, Engel M: Metopic synostosis: measuring intracranial volume change following fronto-orbital advancement using three-dimensional photogrammetry. J Craniomaxillofac Surg 43: 593e598, 2015
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Please cite this article in press as: Wilbrand J-F, et al., Surgical correction of lambdoid synostosis e New technique and first results, Journal of Cranio-Maxillo-Facial Surgery (2016), http://dx.doi.org/10.1016/j.jcms.2016.07.031