1.Brief introduction of congenital craniofacial anomalies.
Congenital craniofacial anomalies are inherited deformities of the skull, orbit, zygoma, upper and lower jaws and deformities of facial soft tissues, often accompanied by functional disorders of the five senses, caused by genetic abnormalities or embryonic developmental abnormalities.
There are many kinds of congenital craniofacial anomalies, including craniosynostosis, craniofacial cleft, orbital distance widening, craniofacial short deformity and craniofacial anomaly syndrome, etc. In severe cases, it may lead to mental retardation and visual impairment, and the deformity of appearance will worsen with age. Its treatment is special and complex.
The cranial X-ray, CT and MR examinations are helpful for early detection of lesions, early diagnosis, timely treatment and correction of deformities, which not only can correct deformities and restore normal appearance, but more importantly, can eliminate the pathological pressure and obstruction of craniofacial bones on the brain and five senses, so that the central nervous system of the brain and sensory system of five senses can grow and develop normally, and make the child grow up healthy physically and mentally, and also relieve At the same time, it can also relieve the huge psychological pressure and economic burden on the relatives of the child’s family.
2.Mid-craniofacial cleft (Tessier0-14).
The history of human scientific understanding of congenital craniofacial anomalies began with the original research work of the famous German pathologist Virchow in the 17th century 1851. The history of mankind’s ability to systematically and reasonably treat craniofacial deformities began with the pioneering work of the famous French doctor Tessier in the 1960s, less than 50 years ago, and in these short decades a new branch of surgery for craniofacial deformities – craniofacial surgery was born. With the rapid development of science and technology since the 1960s, craniofacial surgery treatment methods, surgical procedures, surgical instruments, micro power equipment, anesthesia monitoring technology, etc., with the times, constantly updated development.
3, various types of craniofacial deformities, etiology.
(1) Types of congenital craniofacial malformations: craniofacial cleft, orbital spacing widening, cranial suture premature closure (cranial malformation), craniofacial asymmetric malformation, meningocele, craniofacial hemangioma, lymphadenoma, neurofibroma, abnormal proliferation of craniofacial fibers, congenital microphthalmia, ptosis, craniofacial malformation syndrome.
(2) Etiology of congenital craniofacial malformations.
Genetic factors: one or both parents have deformities; consanguineous marriage; chromosomal or genetic mutations.
Environmental factors: industrial “three wastes”, pesticides, food additives and preservatives contain teratogenic chemicals.
Chemical drugs: chemotherapy drugs, certain antibiotics, drugs for psychiatric treatment, hormones, etc.
Radiation: Radiation exposure or exposure to radioactive substances during pregnancy.
Physical factors: mechanical pressure, temperature.
Biological factors: infection with rubella, cytomegalic, herpes simplex and mumps influenza viruses, toxoplasmosis, syphilis spirochetes during pregnancy.
Metabolic and endocrine diseases: mothers with diabetes are prone to malformed children.
Other teratogenic causes: alcoholism, heavy smoking, lack of oxygen, severe malnutrition, etc. have teratogenic effects.
4.The morphology, pathogenesis and principles of surgery of various craniofacial malformations.
(1) Craniofacial cleft: Craniofacial cleft is a congenital cleft defect through the skull, orbit, maxillofacial bone and craniofacial soft tissue. Craniofacial clefts can exist in many forms and vary in severity. Although their clinical presentation is bizarre and difficult to describe, most craniofacial clefts follow the line of embryonic development or the gap between the craniofacial embryonic prominences.
Principles of surgical treatment of craniofacial clefts: In general, the timing of revision surgery depends on the severity of the craniofacial deformity and the degree of threat to life function. For mild craniofacial clefts without functional impairment, surgery can be performed at a later date. Delayed surgery allows the surgeon to take advantage of the infant’s rapidly growing skull, facilitating repair surgery and accurate anatomical landmarks. When severe deformities affect function, initial revision should begin as early as safely possible, and early surgical revision has been shown to be beneficial to the child’s healthy development and to prevent functional impairment. Surgical correction in infancy 1-2 years is usually limited to soft tissue procedures. Soft tissue fissures require careful layered suturing to avoid depressed scars. In cases of scar contracture or shortening in length, a “Z” plication can be used to reduce tension. The incision should be placed in an area where normal aesthetics can be maintained.
Repair of craniofacial cleft bone defects may be deferred. Early embedded bone grafting may interfere with or impede the growth potential of the craniofacial skeleton, and there is the potential for significant bone resorption with apposed bone grafting. As the child grows older, plastic repair of the craniofacial skeleton is necessary, which is as important as soft tissue cleft closure. Without good craniofacial skeletal support, soft tissue reconstruction will not maintain good long-term results. The timing of craniofacial bone reconstruction is determined according to the patient’s craniofacial development and dental and jaw growth, and can be arranged at preschool age (5-7 years old) as appropriate, usually after 12-14 years old for osteotomy and bone graft reconstruction to repair skeletal defects or deformities.
(2) Widening of orbital distance: Widening of orbital distance is a congenital craniofacial deformity in which the inter-orbital distance (IOD) is wider than normal on both sides. For example, Tessier’s 0-14, 1–13, 2–12, and 3–11 craniofacial clefts can all produce a widened orbital distance.
Diagnostic classification of orbital spacing (IOD) is slightly wider in oriental people than in western people, and it is generally considered that any orbital spacing between 25 and 29 mm can be considered as normal range.
(3) Congenital craniosynostosis (leading to various cranial deformities).
(1) Classification of cranial suture premature closure disorder.
Triangular head deformity: premature closure of frontal suture; navicular head deformity: premature closure of sagittal suture; short head deformity: premature closure of coronal suture; oblique head deformity: premature closure of hemilateral coronal suture.
The pathogenesis of craniosynostosis and the principles of surgical plastic repair.
The skull grows faster at 1-2 years old after birth, and slows down after 5 years old, and reaches 90% of the adult size around 7 years old. Posterior fontanelle and butterfly fontanelle are closed at 2-3 months after birth, mastoid fontanelle is closed at 1 year after birth, and anterior fontanelle is closed at about 2.5 years old. The frontal suture fuses at 8 years of age, and the sagittal, coronal and herringbone sutures fuse in adulthood. If the cranial suture closes too early, the normal growth and development of the skull cap, skull base, orbit, and jaw bone will be hindered, and various craniofacial deformities will occur, resulting in narrow cranial and orbital cavities, limiting the growth and development of the central nervous system of the brain, and craniofacial deformities will gradually increase with age, resulting in intracranial hypertension, brain function and intellectual developmental disorders, optic nerve atrophy, and other serious complications.
Triangular head deformity: is due to the early closure of the frontal suture resulting in a triangular frontal bone, so called triangular head deformity.
The age of surgical plastic surgery is: 7 months – 7 years old.
The principle of plastic surgery and the basic procedure: the supraorbital bridge and the triangular prominence in the center of the frontal bone are fractured and corrected by the green branch to form the normal frontal shape and curvature.
Navicular head deformity: It is a cranial deformity in which the lateral development of the head is limited due to the premature closure of the sagittal suture, and the head grows in the direction of the front and back of the sagittal suture, forming a narrow and long canoe shape.
Age of surgery: 4 months-4 years old.
The principle of surgery is: to cut the sagittal suture, to expand the parietal and temporal bones to both sides, to expand the cranial cavity to facilitate brain growth and development, and also to restore the skull shape to normal.
Short head deformity: It is due to the premature closure of bilateral coronal suture, which causes the frontal bone and upper orbital area to be retracted and tilted, and the growth of the skull is blocked in the front and backward direction, but grows laterally along the coronal suture, forming short head deformity.
Age of surgery: It is advisable to operate within 1 year old.
The principle of surgery: expand the cranial cavity to release the intracranial hypertension, so that the brain can grow and develop normally. The most commonly used is Marchac floating frontal flap surgery, which can obtain a good frontal orbital shape.
Oblique head deformity: The frontal orbital development on one side is limited due to unilateral premature closure of the coronal suture, and the frontal orbital is posteriorly retracted and oblique, making the two sides of the skull significantly asymmetrical.
The age of surgery: 6 months to 12 months old is the best.
There are various surgical methods, but the basic principle is: to cut open the prematurely closed coronal suture and pterygomatic suture, to move forward the retracted frontal bone and orbits, and to recreate the frontal orbital shape.
(4) Craniofacial deformity syndrome (cranial and facial bone complex deformity): there are many kinds of craniofacial deformity syndrome, and Crouzon syndrome and Treacher-Collins syndrome are relatively common in clinical practice.
Crouzon’s syndrome was reported by French doctor Crouzon in 1912, who named the syndrome he described as Crouzon’s syndrome.
Symptoms and diagnosis】 Frog eyes, parrot nose, and disc-shaped face are the typical symptoms.
1. Cranial deformity: Short head deformity may appear. Craniofacial Crouzon syndrome sometimes has premature closure of the sagittal suture, narrowing of the anterior cranial sulcus, widening of the orbital spacing, chronic intracranial hypertension, and numerous fingerprick marks on the intracranial plate.
Facial deformity: Facial deformity is the most typical. The midface is a sunken disc-shaped face, with poor dental occlusion, misaligned teeth, and an anticlinal shape. The zygomatic bone and orbital area are underdeveloped, and the orbital cavity becomes too small to accommodate the eyeballs, resulting in protruding eyes, which look like frog eyes. The nasal root is collapsed, the bridge and nostrils are wide, and the tip of the nose is bowed and elevated in the shape of a parrot’s beak.
3.Dysfunction: The palate is narrow and long, and the palatal lid is high and arched. The nasopharyngeal cavity is small, which sometimes affects breathing and causes snoring. In severe cases, it causes obstructive sleep apnea syndrome. The effect of vision is mainly due to incomplete eyelid closure and long-term corneal exposure leading to exposure keratitis, which can cause corneal leukoplakia in severe cases and lead to blindness.
4. Intellectual problems: Patients with Crouzon syndrome generally do not have problems with mental retardation, but if it is associated with premature closure of multiple cranial sutures and severe increase in intracranial pressure, mental retardation may occur, and early surgery in this case is still necessary.
Surgical treatment]
The earliest treatment of Crouzon syndrome is traced back to the British doctor Gillies (1942) who applied Le Fort III surgery to truncate the maxilla anteriorly to correct the proptosis and antimandibular deformity. Tessier (1967), a French surgeon, used a combined intracranial-extracranial approach to perform Le Fort type III osteotomy for anterior displacement, filling the osteotomy gap with autologous bone and fixing the anteriorly displaced craniofacial segment with a fixed brace to achieve satisfactory results. Ortiz-Monasterio (1978), a Mexican surgeon, was the first to use a combined intracranial and extracranial approach to perform a mono bloc operation for the anterior displacement of the frontal orbital maxilla, and obtained good results.
In the 21st century, French craniofacial plastic surgeons such as Marchac and Arnaud advocated the use of built-in miniature distraction osteotomies after mono bloc osteotomy to complete the craniofacial plastic surgery by gradual traction. We now also use this technique for the plastic repair treatment of Crouzon syndrome, which is characterized by less trauma, fewer complications, and satisfactory adjustment of the result.
Treacher-Collins syndrome Treacher-Collins syndrome, also known as mandibulo-facial dysostosis (MFD), is a congenital craniofacial dysostosis. It is a congenital craniofacial dysostosis, mainly involving the temporocranial, midfacial, and lower parts of the face. There are both bony abnormalities and typical soft tissue deformities, such as bone fissures or defects at the inferior orbital rim, a subluxation of the external canthus in a reverse Mongolian eye, and loss of the outer 1/3 of the lid margin and eyelashes. According to Tessier’s craniofacial cleft typing, Treacher-Collins syndrome belongs to a compound craniofacial cleft with the simultaneous presence of clefts 6, 7 and 8.
Clinical manifestations and diagnosis
(a) Clinical manifestations of Treacher-Collins syndrome.
(i) Eyelid : anticanthalgic deformity with downward outer eyelid fissure, absence of eyelashes with hypoplasia of the outer lower lid margin and lid plate, and poor attachment of the outer canthus.
(ii) Zygomatic-zygomatic arch region: hypoplasia and absence, flattening of the zygomatic region. Hypoplasia of the lower outer orbital rim and lateral orbital wall, the entire orbital skeleton is oval with an outward and downward slope. Bone clefts are located in the zygomatic arch, zygomatic-frontal suture and zygomaticomaxillary suture.
(iii) Maxilla : Narrow and excessively protruding, with high and narrow palatal arch.
④Mandibular bone: hypoplasia of the mandibular body and ascending branches with bird’s beak deformity, low anterior and high posterior dental planes, Class III malocclusion, and receding chin.
⑤ Nasal bone: anteriorly protruding and wide, flat frontal nasal angle or hawk nose.
⑥Other : There are often external ear deformities, absence of external auditory canal, middle ear abnormalities, hearing loss, and may present with macroglossia.
(ii) X-ray and CT imaging diagnosis.
Cephalometric X-ray has good diagnostic value, CT and 3D CT imaging can show the bone cleft site and bone dysplasia well. Due to the hypoplasia of the mandible and narrow pharyngeal cavity, it can lead to obstructive sleep apnea syndrome, so the morphology and function of the nasopharyngeal and oropharyngeal cavities should be determined and evaluated with the help of X-ray cephalometry, CT measurement, and nasopharyngeal endoscopy when necessary.
【Surgical treatment】.
(i) Age of surgery.
Lid margin repair can be performed within 1 year of age. Midface osteotomy, reconstruction of the zygomatic arch of the zygomatic bone and reconstruction of the orbit and eyelid can be performed at the age of 4 to 10 years. Jaw surgery can be performed at 6 to 10 years of age or after jaw development is complete. External otoplasty reconstruction is generally performed after the age of 6 years, in order to obtain sufficient autologous cartilage for the auricular scaffold.
(B) Surgical methods: For craniofacial compound deformities, joint revision treatment can be performed, and surgical revision can also be performed in stages by site.
1. Hypoplasia of the lower eyelid margin, full-length defect of the lower eyelid margin: It is best to repair the lower eyelid with an upper eyelid flap transferred to the outer canthus, which repairs both the full-length lateral lower eyelid defect and also moves the outer canthus upward. If the lateral canthal ligament is refixed, it can also correct the downward shift of the lateral canthus with a reverse eye deformity.
2.Orbito-zygomatic bone defect: The general principle is that if the reconstruction of the zygomatic arch can be completed earlier before the development of the jaws, it will have a good effect on the coordinated development of the whole craniofacial area. In the area of zygomatic bone defect, a laminated autogenous rib piece is implanted, and bone grafting is done to correct the outward and downward tilt of the external canthus at the same time. The subperiosteal separation can easily reveal the bone defect or bone fissure. Because of the high distal bone resorption of autogenous rib pieces, most surgeons have recently used cranial exostoses to reconstruct the bone structure of the orbitozygomatic region. The free cranial external plate can be taken, or the composite bone flap with cranial membrane cranial external plate tipped with temporal vessels or temporal muscle can be taken for repair.
3, narrow maxillary protrusion: there are two methods to choose from. Mild deformity can be used similar to the hump nose correction surgical method, that is, chisel away the nasal bone block, the edge of the pear-shaped hole on both sides of the maxillary nasal protrusion osteotomy, so that both sides of the nasal dorsal bone block fracture downward and backward displacement, so as to correct the hawk nose deformity, but also to form a more desirable frontal nasal angle. Tessier’s maxillary osteotomy method can be used for more serious cases of maxillary protrusion, and its osteotomy line is equivalent to LeFort type II osteotomy line. After osteotomy, the entire maxilla is disconnected from the midface and skull base and then rotated forward with the nasal root as the fulcrum. The procedure is best performed simultaneously with the mandibular ascending osteotomy or the mandibular body osteotomy forward surgery to ensure the coordination of facial appearance and tooth-dental relationship.
4.Mandibular shortening deformity: For mild deformity, the main purpose is to improve the facial appearance, you can make bone grafting of the mandibular body, plump up the bilateral mandibles, chin bone grafting, or do chin horizontal osteotomy for advancement. In more serious cases, while repairing the zygomatic arch, osteotomy of the upper and lower jaws should be performed to improve the tooth-tooth relationship, expand the pharyngeal cavity to reduce respiratory obstruction, and improve the contour of the lower face. LeFort type I osteotomy, maxillary body rotational advancement, mandibular ascending sagittal split advancement and chin horizontal osteotomy advancement can be used. Three-dimensional multidirectional traction osteogenesis technique has been used in the treatment of Treacher-Collins syndrome to obtain the effect of correcting the deformity and expanding the upper airway at the same time.
(5) Craniofacial asymmetric deformity is a congenital hypoplasia and short deformity of the bone and soft tissues on one side of the craniomaxillofacial region, which is clinically called: craniofacial shortening or hemifacial shortening. It is caused by the obstruction of the development of the first and second gill arches in the fetus in utero, resulting in asymmetric deformity of the craniofacial region on both sides. The degree of deformity can be mild or severe.
Clinical manifestations and diagnosis
The main manifestations are short mandible and maxilla on one side, small ear deformity, and in severe cases, it also affects the adjacent zygomatic bone, temporal bone and expression muscle, masticatory muscle or subcutaneous tissue, and even orbital heterotopia, microphthalmia and orbital and facial cleft. It is classified into five types according to the American doctor Munro’s typology.
Among them, mandibular malformations can be divided into three categories according to their severity.
Type I: minor hairken malocclusion.
Category II: small condylar and mandibular ascending branches.
The third category: complete absence of the ascending branch of the mandible.
Plastic treatment methods
The timing of maxillary and mandibular osteotomy surgery is generally performed after the patient’s jaw development is basically stable. At present, we use the jaw traction lengthening for the correction of maxillofacial asymmetry treatment can be performed early, about 2-4 years of age, some patients can be advanced to about 1 year of age, as appropriate. Traction osteogenesis is simple and safe to perform, and the results are stable and reliable. No bone grafting is required, and the damage is small; postoperative adjustment gradually achieves the desired effect, and the efficacy can be controlled; family members can also learn to adjust the traction device, and the hospital stay is short; no intermaxillary ligature fixation is required, and postoperative diet and life are not affected. The surgery is less traumatic, and the mandible tends to grow and develop normally after the surgery due to physiological stimulation; the maxilla also improves its growth and development vertically and horizontally under the stimulation of opening and closing or occlusion. These are beneficial to the overall development of the patient’s craniofacial and facial appearance, as well as to the patient’s psychological health.
Features of traction osteogenesis]
Craniomaxillofacial Distraction Osteogenesis is a technique to lengthen the bone by fixing two bone segments with soft tissue attachment and blood supply after amputation, and then gradually distracting them at a certain speed, frequency and direction, during which new bone is formed in the gap between the broken ends.
Dr. McCarthy, an American physician, first used retraction osteogenesis to lengthen the human mandible in 1992. We have made technical improvements to the previous method and use a built-in miniature retractor: a preoperative surgical model or surgical simulation is performed to determine the cortical incision line, the position of the fixed titanium nail, the traction direction and the lengthening length. Only the bone cortex is cut during osteotomy to protect the periosteum and inferior alveolar nerve vessels. The position of the titanium nail should avoid the tooth root and the tooth capsule. In general, the intraoral approach is used, leaving no scar on the facial skin.
Distraction osteogenesis is generally completed in four stages.
①Osteotomy: it is better to perform cortical osteotomy, avoid cutting the medullary vessels and try to protect the periosteum.
②Delayed phase: the phase from osteotomy to the beginning of distraction, generally 7-14 days, similar to the early stage of fracture repair, when the osteogenic activity is quite active.
(③) Traction period: the speed of distraction is very important, too slow to cause premature osteogenesis and fusion, too fast to distract the gap fibrous tissue formation, resulting in bone non-union. It is generally believed that the retraction speed is 0.5~1.5mm per day, which is basically the same as the bone matrix synthesis.
④Fixation period: from the completion of traction to the release of the retractor. During this period, the new bone is further formed and matured for alteration and has acquired sufficient strength. This period is generally 6-8 weeks. After this period, the retractor can be removed.