Craniosynostosis, a complex craniofacial condition, impacts approximately 1 in every 2,500 babies in the United States. This article delves into the complexity of this congenital disability, shedding light on its various forms, categorized broadly by either an unknown cause or an underlying condition. Moreover, we explore ICD-10-CM coding for these diagnoses, including the recent updates as of October 1 of this year, designed to reflect the diverse types of craniosynostosis.
Craniosynostosis is a congenital skull malformation resulting from the premature fusion of one or more cranial sutures, the fibrous joints that connect the bones of an infant’s skull. According to the Centers for Disease Control and Prevention (CDC), these sutures allow the skull to expand as the brain grows. Premature fusion of one or more of these sutures can lead to an irregular head shape and potential complications.
Commonly referred to as “craniostenosis” or “synostosis,” the term “craniosynostosis” can be dissected to unveil its meaning: “Cranio-” pertains to the cranium or skull, while “synostosis” signifies the fusion of two or more bones.
Symptoms of Craniosynostosis
The primary symptom of craniosynostosis is an atypical head shape known as plagiocephaly, which may become evident shortly after birth or become more pronounced as the child grows. For instance, one side of the face may exhibit noticeable asymmetry compared to the other.
As Johns Hopkins Medicine reports, additional indicators may include a full or bulging fontanelle (the soft spot on the top of the head), prominent scalp veins, heightened irritability, a high-pitched cry, feeding difficulties, recurrent vomiting, an expanding head circumference, and developmental delays.
Etiology and Risk Factors
The precise cause of craniosynostosis can vary and may result from a combination of genetic and environmental factors. In some cases, craniosynostosis is linked to specific genetic syndromes, while in others, it may occur spontaneously without an apparent underlying cause.
Factors that can increase the chance of an infant developing craniosynostosis include maternal thyroid disease or using certain medications like clomiphene citrate (a fertility drug) shortly before or during pregnancy.
Typically, craniosynostosis is assessed through physical examination by palpating the skull for suture ridges and soft areas. It also involves evaluating neck alignment and facial irregularities. However, the American Association of Neurological Surgeons (AANS) states a radiological assessment is often necessary to confirm the diagnosis, assess the extent of the deformity, and determine the most appropriate course of surgical treatment. While a standard X-ray can reveal the deformity, computerized tomography (CT or CAT scans) offers more detailed insights into the fused sutures and the condition of the underlying brain. Furthermore, three-dimensional (3-D) CT scans can furnish additional details to guide corrective surgical measures.
Exploring the Types of Craniosynostosis
Craniosynostosis can be categorized as nonsyndromic, developing independently without other related abnormalities, or syndromic, originating from an underlying genetic condition. According to Cincinnati Children’s, the various types of craniosynostosis are based on the number of fused bones, which influence the shape of the child’s head. These types encompass single-suture synostosis (primary), double-suture synostosis, and complex multi-suture synostosis.
Single-Suture Synostosis (Primary)
Examples of single suture synostosis, when one skull suture fuses, include:
- Sagittal synostosis (scaphocephaly): The most prevalent form of craniosynostosis, sagittal synostosis occurs when the sagittal suture fuses prematurely. This fusion results in the elongation of the baby’s head in a narrow manner, known as scaphocephaly.
- Unilateral coronal synostosis (anterior plagiocephaly): The second most common type of craniosynostosis, unilateral coronal synostosis, happens when one side of the coronal suture fuses prematurely. This fusion leads to a flattened forehead on the side of the skull where closure occurs (anterior plagiocephaly) and an almond-shaped eye socket.
- Lambdoid synostosis (posterior plagiocephaly): Lambdoid synostosis represents one of the rarer forms of craniosynostosis. Premature fusion of this suture can flatten the back of the baby’s head (posterior plagiocephaly), making one ear appear higher than the other.
- Metopic synostosis (trigonocephaly): Metopic synostosis is another infrequent variant. Premature closure of this suture can result in a triangular-shaped head characterized by narrowness in the front and width at the back (trigonocephaly).
If two skull sutures fuse prematurely, the condition is referred to as double-suture synostosis. Examples of this type include:
- Bicoronal synostosis (brachycephaly): In this form, both sides of the coronal suture fuse prematurely, leading to a broad and shortened head (brachycephaly) and vertical growth in the skull (turribrachycephaly). Bicoronal synostosis is often diagnosed in children with Apert syndrome and Crouzon syndrome.
- Bilambdoid synostosis: Here, both sides of the lambdoid suture fuse, causing the skull to appear wider than normal (posterior brachycephaly).
- Sagittal plus metopic synostosis: In this case, both the sagittal and metopic sutures fuse, resulting in a long and narrow-shaped head (scaphocephaly).
Complex Multisuture Synostosis
More than two skull sutures may fuse in rare instances, leading to complex multisuture synostosis. Examples of this include:
- Bicoronal, sagittal, metopic: This condition arises when the sagittal, metopic, and both sides of the coronal suture fuse. It results in a short and wide head, which may also exhibit a pointed appearance (turribrachycephaly).
- Cloverleaf skull (Kleeblattschadel): A rare form of craniosynostosis, cloverleaf skull occurs when the coronal, sagittal, and lambdoid sutures all fuse. It is often associated with severe cases of Apert syndrome, Crouzon syndrome, and Carpenter syndrome.
- Pancraniosynostosis: All the major sutures in the skull fuse in this exceptionally rare form.
Craniosynostosis can also be associated with an underlying genetic condition. According to Access Anesthesiology, common syndromes linked to craniosynostosis include Crouzon, Apert, Carpenter, Pfeiffer, and Saethre-Chotzen.
- Crouzon syndrome: The most prevalent syndrome associated with craniosynostosis is Crouzon syndrome, particularly the bilateral coronal type. Individuals with Crouzon syndrome often exhibit midfacial abnormalities like forward protrusion of the eyes and airway obstruction. Some cases may also result in hydrocephalus, characterized as fluid buildup in the brain. Generally, there are no limb abnormalities. While a mutation in the FGFR2 gene primarily causes it, some cases occur spontaneously. Crouzon syndrome is also known as acrocephalosyndactyly and was initially termed craniofacial dysostosis.
- Apert syndrome: Also known as acrocephalosyndactyly type I, Apert syndrome is linked to bilateral coronal craniosynostosis. It results in a tall and shortened head, with the fusion of the skull base. Other common abnormalities may affect the hand, elbow, hip, and knee. Facial features often include eye protrusion, wide spacing between the eyes, a prominent pointed nose, and downward-slanting eyelids. These features are usually inherited, and developmental delays and intellectual disabilities are frequently observed in this syndrome.
- Carpenter syndrome: Frequently associated with lambdoid and sagittal synostosis, Carpenter syndrome can lead to limb abnormalities, including extra toes and heart issues. Carpenter syndrome, also called acrocephalopolysyndactyly type II, has not yet been associated with a specific gene.
- Pfeiffer syndrome: Also known as acrocephalosyntactyly type V, Pfeiffer syndrome is often linked to unicoronal craniosynostosis and includes limb abnormalities, midfacial deformities, protruding eyes, and hearing loss. Hydrocephalus is also a common occurrence. Three distinct types of Pfeiffer syndrome have been identified, with types 2 and 3 being the most severe.
- Saethre-Chotzen syndrome: Referred to as acrocephalosyntactyly type III, this congenital syndrome is frequently associated with craniosynostosis and limb abnormalities. Unlike the other syndromes, Saethre-Chotzen syndrome has a distinct genetic profile. Key features include coronal synostosis (often unilateral), a low-set hairline, eyelid abnormalities, facial asymmetry, and developmental delay.
Treatment for Craniosynostosis
Effective treatment options for craniosynostosis primarily involve surgical intervention to rectify the fused sutures, allowing for normal brain and skull growth. Surgical procedures such as cranial vault remodeling or endoscopic craniectomy can alleviate pressure within the head and correct facial and skull bone deformities.
Craniosynostosis that goes untreated may lead to persistent deformities of the head and face, which can impact a child’s self-esteem and social interactions. Additionally, as the Mayo Clinic reports, untreated craniosynostosis, especially those linked to an underlying syndrome, can cause increased cranial pressure and potentially lead to developmental delays, cognitive impairment, blindness, seizures, and headaches.
ICD-10-CM Coding for Craniosynostosis and Craniosynostosis Syndromes
The ICD-10-CM codes for craniosynostosis and associated syndromes can be found in Chapter 17: Congenital Malformations, Deformations, and Chromosomal Abnormalities (Q00-Q99).
Craniosynostosis in ICD-10-CM
Before October 1, 2023, craniosynostosis was reported with code Q75.0. However, this changed with the FY 2024 updates, which introduced a more detailed coding system. For instance, code Q75.0 evolved into category Q75.0, and several new codes were introduced based on the specific type of craniosynostosis.
These newly added codes include:
- Q75.001 Craniosynostosis unspecified, unilateral
- Q75.002 Craniosynostosis unspecified, bilateral
- Q75.009 Craniosynostosis, unspecified
- Q75.01 Sagittal craniosynostosis
- Q75.021 Coronal craniosynostosis, unilateral
- Q75.022 Coronal craniosynostosis, bilateral
- Q75.029 Coronal craniosynostosis, unspecified
- Q75.03 Metopic craniosynostosis
- Q75.041 Lambdoid craniosynostosis, unilateral
- Q75.042 Lambdoid craniosynostosis, bilateral
- Q75.049 Lambdoid craniosynostosis, unspecified
- Q75.051 Cloverleaf skull
- Q75.052 Pansynostosis
- Q75.058 Other multi-suture craniosynostosis
- Q75.08 Other single-suture craniosynostosis
- Q75.009 Craniosynostosis unspecified
Craniosynostosis Syndromes in ICD-10-CM
ICD-10-CM codes for craniosynostosis syndromes remain consistent with FY 2023. Crouzon syndrome is assigned its unique code:
Q75.1 Craniofacial dysostosis (Crouzon’s disease)
Meanwhile, Apert, Pfeiffer, Carpenter, and Saethre-Chtozen syndromes share the same code and are reported along with various other syndromes using:
Q87.0 Congenital malformation syndromes predominantly affecting facial appearance
- Acrocephalosyndactyly [Apert]
- Cryptophthalmos syndrome
- Goldenhar syndrome
- Moebius syndrome
- Oro-facial-digital syndrome
- Robin syndrome
- Whistling face
As mentioned earlier, Apert syndrome, Carpenter syndrome, and Pfeiffer syndrome are also known as acrocephalosyndactyly.
An instructional note at Q87 indicates an additional code(s) should be used to identify all associated manifestations.
All codes from Chapter 17 must be used on the baby’s records, not the maternal records.
In summary, craniosynostosis can occur as a primary condition (nonsyndromic) or as part of a larger genetic syndrome (syndromic). In cases where a child experiences syndromic craniosynostosis and specific cranial sutures fuse, such as bi-coronal synostosis, a comprehensive evaluation by medical professionals is crucial for accurate diagnosis and management. Furthermore, medical coders must be well-versed in the various types of craniosynostosis and proficient at assigning the appropriate codes, including the newly expanded nonsyndromic codes that took effect on October 1 of this year.
I submitted this article to BC Advantage/www.billing-coding.com for their publication. It is reprinted here with their permission.