Craniomaxillofacial Reconstructive and Corrective Bone Surgery - part 10 pdf

706 J.L. Frodel, Jr. a b FIGURE 56.11 Right infraorbital rim defect with onlay bone graft. (a) Right infraorbital rim defect temporarily bridged with a miniplate. (b) Inset onlay bone graft technique with lag screw fixation of right infraorbital rim defect. 56. Calvarial Bone Graft Harvesting Techniques 707 a b FIGURE 56.12 Left lateral zygomaticomaxillary buttress defect. (a) Left lateral zygomaticomaxillary buttress defect bridged with miniplate. (b) Wedged bone graft with good bony contact under miniplate of left lateral zygomaticomaxillary buttress defect. 708 J.L. Frodel, Jr. Case 5 Figure 56.13a shows a larger left maxillary buttress defect. Figure 56.13b demonstrates placement of a large calvarial bone graft that is contoured in a concave shape and secured superiorly and inferiorly by lag screw fixation. Case 6 Pictured and diagrammed (Figure 56.14) is a right zygomatic arch defect after zygomatic repositioning. Because of the con- cerns for excessive lateral projection by placement of an over- lay bone graft, the residual bone adjacent to the defect is trimmed from the undersurface, allowing for placement of an appropriately contoured bone graft. This is subsequently fix- ated by the lag screw technique. Case 7 A large calvarial defect is shown [Figure 56.15(a)] following a traumatic injury, which encompasses the entire right frontal a b FIGURE 56.13 Large left anterolateral maxillary defect with onlay bone graft reconstruction. (a) Left anterolateral maxillary bone defect. (b) Calvarial onlay bone graft with lag screw fixation reconstruction. a b c FIGURE 56.14 Diagrams demonstrating (a) right zygomatic defect and (b,c) place- ment of a calvarial bone graft using an underlay technique stabilized by lag screw fixation. 710 J.L. Frodel, Jr. a b FIGURE 56.15 Large right frontal cranial and supraorbital rim defect with calvarial bone graft reconstruction. (a) Large right frontal cra- nial and supraorbital rim defect. (b) Multiple calvarial bone grafts with miniplate fixation for reconstruction of large right frontal cra- nial and supraorbital rim defect. 56. Calvarial Bone Graft Harvesting Techniques 711 a b FIGURE 56.16 Collapse of anterior frontal bone after frontal sinus in- fection with calvarial bone graft reconstruction. (a) Anterior frontal bone defect. (b) Following frontal sinus debridement, reconstruction of anterior frontal bone with multiple calvarial bone grafts using lag screw fixation. cranial and supraorbital rim and roof region. Figure 56.15b shows reconstruction of this defect using multiple calvarial bone grafts and miniplate fixation. Case 8 This case demonstrates loss of the anterior table of the frontal sinus with a subsequent frontal deformity (Figure 56.16). Af- ter removal of residual sinus disease and burring down of the bone, multiple bone grafts are placed and stabilized by lag screw fixation. Contouring was then performed to reconstruct the normal frontal orbital shape. Case 9 Pictured and diagrammed (Figure 56.17) is a large anterior cranial-based defect. As this connects with the nasopharynx, this defect is reconstructed with two calvarial bone grafts placed onto the residual anterior fossa floor and roof of the orbit and stabilized with lag screw fixation. Resorbable screws may be used in these circumstances with less concern for hard- ware removal or migration. 14,15 Summary In conclusion, calvarial bone grafting provides an excellent tool in the armamentarium for craniomaxillofacial recon- struction. Key considerations include having proper equip- ment as well as patience during graft harvesting, maintaining the osteotome or saw position in the space between the inner and outer cortices of the calvarium, preparation of the recip- ient bed after selection of the appropriately shaped bone graft, and the use of rigid internal fixation utilizing the lag screw technique whenever possible. Resorbable screws may be used when adequate stabilization can be achieved, avoiding the se- quelae of screw head palpation from graft resorption, or the need for hardware removal. 14,15 712 J.L. Frodel, Jr. References 1. Smith ID, Abramson M. Membranous vs. endochondral bone autografts. Arch Otolaryngol Head Neck Surg. 1983;99:203– 205. 2. Zins JE, Whitaker LA. Membranous vs. endochrondral bone grafts: implications for craniofacial reconstruction. Plast Re- constr Surg. 1985;76:510–514. 3. Kusiak JF, Zins JE, Witaker LA. The early revascularization of membranous bone. Plast Reconstr Surg. 1985:76:510–514. 4. Hardesty RA, Marsh JL. Craniofacial onlay bone grafting: a prospective evaluation of graft morphology, orientation, and em- bryologic origin. Plast Reconstr Surg. 1990;85:5–15. 5. Moore KI. The Developing Human. 2nd ed. Philadelphia: WB Saunders; 1977:307–309. 6. Craft PD, Sargent LA. Membranous bone healing and tech- niques in calvarial bone grafting. Clin Plast Surg. 1989;16:11– 19. 7. Phillips JH, Rahn BA. Fixation effects on membranous and en- dochondral onlay bone-graft resorption. Plast Reconstr Surg. 1988;82:872–877. 8. Pensler J, McCarthy JC. The calvarial donor site: an anatomic study in cadavers. Plast Reconstr Surg. 1985;75:648–651. 9. Powell NB, Riley, RW. Cranial bone grafting in facial aesthetic and reconstructive contouring. Arch Otolaryngol Head Neck Surg. 1987;Jul;113(7):713–719. 10. Sheen JH. A change in the site for cranial bone harvesting. Prospect Plast Surg. 1990;4:48–57. 11. Frodel JL, Marentette LJ, Quatela VC, Weinstein GS. Cal- varial bone graft harvest: techniques, considerations, and mor- bidity. Arch Otolaryngol Head Neck Surg. 1993;119:17–23. 12. Frodel JL. Complications of bone grafting. In: Eisele DW, ed. Complications in Head and Neck Surgery. St. Louis: CV Mosby; 1993:773–784. 13. Frodel JL, Marentette LJ. Lag screw fixation in the upper cran- iomaxillofacial skeleton. Arch Otolaryngol Head Neck Surg. 1993;119:297–304. 14. Kurpad SN, Goldstein JA, Cohen AR. Bioresorbable fixation for congenital pediatric craniofacial surgery: a 2 year followup. Pediatr Neurosurg. 2000;33:306–310. 15. Pensler JM. Role of resorbable plates and screws in craniofa- cial surgery. J Craniofac Surg. 1997;8:129–134. F IGURE 56.17 Large anterior cranial fossa defect following a gunshot wound with calvarial bone graft reconstruction. (a) Anterior cranial fossa defect. (b) Reconstruction of anterior cranial fossa floor defect with two calvarial bone grafts using a lag screw fixation. a b 713 57 Crouzon Syndrome: Basic Dysmorphology and Staging of Reconstruction Jeffrey C. Posnick Crouzon syndrome is the most frequent form of craniofacial dysostosis. 1–6 It is characterized by multiple anomalies of the craniofacial skeleton. Its manifestations are generally less se- vere than those of Apert syndrome, and there is no involve- ment of the extremities. Typically, the cranial vault presen- tation is a brachycephalic shape to the skull caused by premature synostosis of both coronal sutures. Cranial vault suture involvement, other than coronal, may include sagittal, metopic, or lambdoidal in isolation or in any combination. The cranial base and upper face sutures are generally in- volved, resulting in a variable degree of midface hypoplasia with an angle class III malocclusion. The orbits are hy- poplastic, resulting in a degree of proptosis with additional orbital dysplasia that may produce a mild to moderate orbital hypertelorism and flatness to the (transverse) arc of rotation of the midface. 7–13 The lack of consensus about the timing and techniques used at each stage of reconstruction reflects uncertainty about the functional consequences of the congenital dysmorphology and inconsistencies of the results achieved with any one ap- proach to treatment. 14–41 Accurate objective methods for doc- umentation of either the presenting deformity or initial and late postoperative results are few. Too much reliance has been placed on the subjective assessment of both the presenting de- formity and the postoperative results achieved. Functional Considerations Brain volume in the normal child almost triples in the first year, 42–46 and by 2 years the cranial capacity is four times that at birth. In craniosynostosis, premature suture fusion is combined with continuing brain growth. Depending on the number, location, and rate of prematurely fused sutures, the growth of the brain may be restricted. If early surgical in- tervention with suture release, decompression, and reshap- ing to restore a more normal intracranial volume and con- figuration does not reverse the process, diminished central nervous system function may be the end result. Elevated in- tracranial pressure is the most important functional problem associated with premature suture fusion. 26,32,34,40 If in- tracranial hypertension goes untreated, brain function is ad- versely affected. When craniosynostosis is associated with increased in- tracranial pressure, optic nerve compression occurs. Initially, there is papilloedema with eventual optic atrophy that results in partial or complete blindness. Fundoscopic examination of the retina should reveal papilloedema, allowing for surgical intervention to limit the late effects. If the orbits are shallow and the eyes proptotic, corneal dry- ing may occur, which can result in ulceration. If the orbits are extremely shallow, herniation of the globes may occur, re- quiring emergency reduction. Divergent or convergent non- paralytic strabismus or exotropia occurs frequently and should be looked for and treated. Hydrocephalus affects 5% to 10% of children with Crouzon syndrome. 47 Although the etiology is not always clear, hydrocephalus may be secondary to a gen- eralized cranial base stenosis with constriction of the cranial base foramina. When the clinical examination is correlated with serial computed tomographic (CT) scans or magnetic res- onance imaging to document progressively enlarging ventri- cles, a more accurate diagnosis can be determined. When hy- drocephalus is detected, prompt ventriculoperitoneal shunting should be performed. All neonates are obligate nasal breathers. A significant per- centage of children born with Crouzon syndrome have severe hypoplasia of the midface with diminished nasal and na- sopharyngeal spaces. This malformation increases nasal air- way resistance and forces infants to breathe primarily through their mouth. This type of breathing may result in inadequate oxygenation with a tracheostomy being required. In Crouzon syndrome, conductive hearing deficit is fre- quently encountered, and atresia of the external auditory canals may also occur. 48 Aesthetic Assessment Examination of the entire craniofacial region (skeletal and soft tissues) should be systematic and complete. Specific findings 714 J.C. Posnick are frequent in Crouzon syndrome, but each patient is unique. Achievement of symmetry, proportionality, and balance is critical to reconstructing an attractive face in a child born with Crouzon syndrome. The upper third of the face is generally dysmorphic in an infant born with Crouzon syndrome. The establishment of the preferred position of the forehead is essential to the over- all facial balance. 49 The forehead is divided into two sepa- rate components, the supraorbital ridge and the superior forehead. The supraorbital ridge includes the glabella re- gion; the supraorbital rim and its lateral extension posteri- orly along the temporoparietal bones; and inferiorly down the frontozygomatic suture region. In Crouzon syndrome with brachycephaly present, this component is retruded and wide. Ideally, the eyebrows, overlying the supraorbital ridges, should rest anterior to the cornea when viewed in profile. When the supraorbital ridge is viewed from above, the rim should arc posteriorly to achieve a gentle 90° angle at the temporal fossa with the center point of the arc located at the level of each frontozygomatic suture. The superior forehead component, about 1.5 cm up from the supraorbital rim, has a gentle posterior curve of 60°, leveling out at the coronal suture region when seen in profile. The brachy- cephalic skull of Crouzon syndrome lacks this preferred su- perior forehead morphology. In Crouzon syndrome, presenting with bilateral coronal su- ture synostosis extending into the cranial base, the orbitona- sozygomatic region is wide and lacks forward projection. These findings are consistent with a short and wide anterior cranial base. Overall midface projection is deficient, and the upper anterior face appears vertically short from the nasion to the maxillary central incisors. 8,9,12 Quantitative Assessment The purpose of a quantitative assessment of the craniofacial complex by CT scan analysis, 9,12,50–54 anthropometric mea- surements, 8,55 cephalometric analysis, and dental model analysis is to help predict growth patterns, confirm or refute clinical impressions, aid in treatment planning, and provide a framework for objective assessment of the immediate and long-term reconstructive results. We developed a method of analysis based on CT scan measurements which allows for a more quantitative assess- ment of the cranio-orbito-zygomatic skeleton in both the horizontal and transverse planes. 50,51 A normative database is established using this system which enables comparison of an individual patient’s cranio-orbito-zygomatic morphol- ogy with that of an age-matched cohort group. 51 Posnick et al. developed this method of quantitative CT scan analysis and then used it to document the differences in the cranio-orbito-zygomatic region between unoperated chil- dren with Crouzon syndrome and age-matched controls. 9,12 Posnick et al. also evaluated the morphologic results achieved in those children 1 year after undergoing a standard suture re- lease, anterior cranial vault, and upper orbital procedure de- signed to decompress and reshape these regions. 12 The preoperative CT scan measurements of these unop- erated Crouzon children confirmed a widened anterior cra- nial vault at 108% of normal and a cranial length averaging only 92% of normal. In comparison with age-matched con- trols, orbital measurements revealed a widened anterior in- terorbital distance at 122% of normal, an increased in- tertemporal width at 121% of normal, globe protrusion at 119% of normal, and a short medial orbital wall distance at only 86% of normal. The distance between the zygomatic buttresses and the interarch distances were found to be in- creased at 106% and 103% of normal, respectively. The zy- gomatic arch lengths were substantially shortened at only 87% of age-matched control values. 12 These findings con- firmed clinical observations of brachycephalic anterior cra- nial vaults with shallow, frequently hyperteloric orbits and globe proptosis. Generally, the Crouzon midface is hori- zontally retrusive and transversely wide, reflected in wide and shortened zygomas. The same quantitative CT scan assessment was carried out in the operated Crouzon children more than 1 year after un- dergoing anterior cranial vault and upper orbital osteotomies with reshaping, and when comparing them to the new age- matched control values, we were not able to demonstrate any significant improvement in the cranio-orbito-zygomatic mea- surements. 12 In the midchildhood years, another group of Crouzon chil- dren were again assessed using the quantitative CT scan mea- surements. 56 They were found to have cranial vault lengths averaging only 87% of the age-matched normals. The medial orbital walls were (horizontally) short at 87% of normal while the extent of globe protrusion was excessive at 134% of age- matched norms. The zygomatic arch lengths averaged only 84% of normal. These findings confirmed horizontal (antero- posterior) deficiency of the upper and middle facial thirds. After undergoing a monobloc osteotomy (orbits and midface) combined with anterior cranial vault reshaping and advance- ment carried out through an intracranial approach, the chil- dren’s cranio-orbito-zygomatic measurements were again taken. The mean cranial length initially achieved (after monobloc osteotomy) was 98% and at 1 year 92% of the con- trol value. When compared with age-matched controls, the or- bital measurements reflected improvement in the midorbital hypertelorism (midinterorbital distance, 97% initially after operation and 102% at 1 year), and orbital proptosis (soon after surgery, 86%, and at 1 year, 92% of age-matched normals). The medial orbital wall length initially normalized at 101% and later at 97% of normal values. The zygomatic arch length initially corrected at 106% and later to 101% of normal. 57. Crouzon Syndrome: Dysmorphology and Reconstruction 715 Surgical Approach: Historical Perspective The first recorded surgical approach to craniosynostosis was performed by Lannelongue in 1890 57 and Lane in 1892, 58 who completed strip craniectomies. Their aim was to con- trol the problem of brain compression within a congenitally small cranial vault. The classic neurosurgical techniques were refined over the ensuing decade and geared toward re- secting the synostotic suture(s) in the hope that the “re- leased” skull would reshape itself and continue to grow in a normal and symmetric fashion. The strip craniectomy pro- cedures were supposed to allow for a creation of new suture lines at the sites of the previous synostosis. With the real- ization that this goal was rarely achieved, attempts were made to fragment the cranial vault surgically with pieces of flat bone used as free grafts to refashion the cranial vault shape. Problems with these methods included uncontrolled postoperative skull molding, resulting in reossification in dysmorphic configurations. In 1950, Gillies reported his experience with an extracra- nial (elective) Le Fort III osteotomy to improve the anterior projection of a patient with Crouzon syndrome. 59 His early enthusiasm later turned to discouragement when the patient’s facial skeleton relapsed to its preoperative status. In 1967, Tessier described a new (intracranial-cranial base) approach to the management of Crouzon syndrome. 17 His landmark presentation and publications were the beginning of modern craniofacial surgery. 19,60–64 To overcome Gillies’ earlier problems, Tessier developed an innovative basic surgical ap- proach that included new locations for the Le Fort III os- teotomy, a combined intracranial-extracranial (cranial base) approach, use of a coronal (skin) incision to expose the up- per facial bones, and the use of autogeneous bone graft. He also applied an external fixation device to help maintain bony stability until healing had occurred. The concept of simultaneous suture release for craniosyn- ostosis combined with cranial vault reshaping in infants was initially discussed by Rougerie et al. 65 and later refined by Hoffman and Mohr in 1976. 22 Whitaker et al. 66 proposed a more formal anterior cranial vault and orbital reshaping pro- cedure for unilateral coronal synostosis in 1977, 66 and then Marchac and Renier published their experience with the “floating forehead” technique for simultaneous suture release and anterior cranial vault and orbital reshaping to manage bi- lateral coronal synostosis in infancy. 67,68 The widespread use of autogenous cranial bone grafting has virtually eliminated rib and hip grafts when bone re- placement or augmentation is required in cranio-orbito-zygo- matic procedures. 69 This represents another of Tessier’s con- tributions to craniofacial surgery. 62 Phillips and Rahn documented through animal studies the advantages of stable fixation of grafts (lag screw techniques) to encourage early healing and limit graft resorption. 70 In current practice, the use of mini- and micro internal plate and screw fixation is the preferred form of fixation when stability and three- dimensional reconstruction of multiple osteotomized bone segments and grafts are required. 71–75 Surgical Approach: Author’s Current Staging of Reconstruction Primary Cranio-Orbital Decompression: Reshaping in Infancy The most common cranial vault suture synostosis pattern as- sociated with Crouzon syndrome is bilateral, premature coro- nal suture fusion that extends into the cranial base (Figures 57.1–57.3). 4 In infancy and early childhood, it is not always possible to separate “simple” brachycephaly (bilateral coro- nal synostosis) from Crouzon syndrome unless either midface hypoplasia is evident or a family pedigree with an autosomal dominant inheritance pattern is known. 4 The midface FIGURE 57.1 Illustration of the craniofacial skeleton in a child with Crouzon syndrome before and after cranio-orbital reshaping. (Above) Site of osteotomies. (Below) After osteotomies, reshaping, and fixation of the cranio-orbital regions. (From Posnick 10 ) [...]... craniofacial skeletal deformities (most notably the mandible and temporomandibular joint complex), and soft tissue deficiencies The most commonly affected structures are the external and middle ear, condyle and ramus of the mandible, muscles of mastication, parotid gland, zygomatic bone and arch, temporal bone, maxilla, and orbit The abnormalities of the temporomandibular joint (TMJ) range from complete agenesis... through the cranial vault of the 6-month-old girl with Crouzon syndrome (from Figure 57.2) before and 1 year after cranio-orbital reshaping The cranial length has increased from 114 to 138 mm The anterior intracranial width has increased from 100 to 108 mm and remains at 105 % of the age-matched controls (b) Comparison of standard axial-sliced CT scans through midorbit before and 1 year after reconstruction... mandibular deformity.36 Each grade increases in severity until in grade 3 cases deformities may present with complete agenesis of the ramus Swanson and Murray recognized the fact that the temporomandibular joint may be significantly deformed and acknowledged this in their classification of mandibular and temporomandibular deformities of HFM.39 In 1985, Lauritzen et al classified mandibular-temporomandibular... comparison of microtia and temporal bone anomalies in hemifacial microsomia and mandibulofacial dysostosis Cleft Palate J 1980;17 :103 – 110 36 Pruzansky S Not all dwarfed mandibles are alike Birth Defects 1969;5:120–129 37 Longacre JJ, DeStefano GA, Holmstand KE Surgical management of first and second branchial arch syndromes Plast Reconstr Surg 1963;31:507–520 38 Converse JM, Wood-Smith D, McCarthy JG,... osteotomy with bone plates and screws Split cranial grafts harvested from left parietal region and interposed in nasofrontal region and zygomatic arches (l) Lateral cephalometric radiograph before and after reconstruction (From Posnick13) 722 J.C Posnick a b c d e FIGURE 57.6 A 6-year-old girl with Cruzon syndrome who underwent anterior cranial vault and monobloc osteotomies with reshaping and advancement... occlusal plane and requires only onlay bone grafting for cosmesis plus orthodontic intervention The 734 temporomandibular joint and ramus are only slightly deformed For types IB to V there is an occlusal tilt and malocclusion of a severity that warrants surgical intervention The appropriate procedure is based upon the adequacy of the temporomandibular (TMJ)-mandibular complex To try and maximize maxillary... 57.2 A 6-month-old girl with Crouzon syndrome underwent cranio-orbital reshaping (a) Preoperative frontal view (b) Frontal view 10 days later (c) Preoperative profile view (d) Profile view 10 days later (e) Frontal view 3 years later (f) Profile view 3 years later (From Posnick et al .10) 57 Crouzon Syndrome: Dysmorphology and Reconstruction 717 a b c FIGURE 57.3 (a) Comparison of standard axial-sliced... 1988;25:235–244 9 Carr M, Posnick J, Armstrong D, et al Cranio-orbito-zygomatic measurements from standard CT scans in unoperated Crouzon and Apert infants: comparison with normal controls Cleft Palate Craniofac J 1992;29:129–136 10 Posnick JC Craniosynostosis: surgical management in infancy In: Bell WH, ed Modern Practice in Orthognathic and Reconstructive Surgery Philadelphia: WB Saunders; 1992:1889–1931 11... of the anterior cranial vault and simultaneous anterior cranial vault and upper orbital osteotomies with reshaping and advancement .10, 12,24,33,41,66–68 My preference is to carry this out when the child is 10 to 12 months old unless signs of increased intracranial pressure are identified earlier in life .10, 12,41 Reshaping of the upper three-quarters of the orbital rims and supraorbital ridges is geared... condyle to complete absence of the affected ramus and condyle and much of the body The affected condyle is always abnormal, and this is probably the only constant feature of HFM The mandibular-temporomandibular deformity varies from a minimal deformity of the complex to a complete absence Frequently there is a bony deformity of the squamous temporal bone, and the posterior wall of the glenoid fossa may . anterior intracra- nial width has increased from 100 to 108 mm and remains at 105 % of the age-matched controls. (b) Comparison of standard axial-sliced CT scans through midorbit before and 1 year after. eliminated rib and hip grafts when bone re- placement or augmentation is required in cranio-orbito-zygo- matic procedures. 69 This represents another of Tessier’s con- tributions to craniofacial surgery. 62 Phillips. Membranous bone healing and tech- niques in calvarial bone grafting. Clin Plast Surg. 1989;16:11– 19. 7. Phillips JH, Rahn BA. Fixation effects on membranous and en- dochondral onlay bone- graft resorption.