Clinical Significance of Intracranial Heterotopic Ossification:A Search for Etiology Using a Decedent Imaging Database

Andrew C. Norred, BS, Taylor Koscho, MS, Melinda L. Carter, MD, PhD

Group: Orthopedics

Anatomic variation within the confined spaces of the cranium can contribute to neurovascular pathology and may also create obstacles during surgical procedures. Prior work by Ekanem et al. described variation in the inferior petrosal sinus groove along the posterior petrous temporal bone, highlighting its potential to hinder venous sinus sampling for evaluating pituitary gland secretions. Although mineralization of soft tissue structures within the cranium has been documented both grossly and radiologically, the underlying causes remain poorly understood. To support upcoming research using the New Mexico Decedent Imaging Database (NMDID), we conducted a literature review to assess current clinical and anatomical knowledge regarding these calcified variations, with particular attention to their associations with aging and systemic health.

We reviewed intracranial examples of heterotopic calcification involving the jugular foramen (Figs. 1 and 2), petroclinoid ligament (Figs. 1 and 3), pineal gland, and choroid plexus (Fig. 4), with attention to the clinical significance associated with each structure. To contextualize these findings, we conducted a literature search using PubMed, Google Scholar, and related databases to identify publications from the past five to ten years that address mineralization of intracranial soft tissue structures, focusing particularly on those located outside the central nervous system. Figure 1 illustrates the endocranial positions of the jugular foramen and petroclinoid ligament, both of which are present bilaterally.

Ossified septations were identified in 8.5% of skulls (n= 100, 200 sides), complicating surgical procedures and increasing the risk of neurovascular injury.

Gross examples of ossified soft tissue within the jugular foramen:

Petroclinoid Ligament:

• Calcification can complicate microsurgical access to the cavernous sinus and increase the risk of nerve impingement, particularly the oculomotor nerve.

• Ossification is often linked to age and systemic conditions such as fluorosis.

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Pineal Gland:

• Commonly calcified in adults, with prevalence and intensity increasing with age, particularly in males.'

• While benign, pineal gland calcifications are valuable markers for distinguishing physiological changes from pathological findings."

Choroid Plexus:

• Often incidental findings on CT imaging but require differentiation from pathological conditions such as vascular malformations or tumors?

• In schizophrenia, increased calcification may indicate blood-brain barrier dysfunction, impacting neurotransmitter regulation."

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  Incidence and Patterns:

  • Intracranial heterotopic ossification is increasingly observed with age, particularly in the pineal gland, choroid plexus, petroclinoid ligaments, anc

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  jugular foramen.s?a

  • Calcification prevalence and intensity vary across demographics, with older adults exhibiting a higher incidence.*.s Clinical and Diagnostic Importance:

  • Age-related calcifications must be distinguished from pathological conditions to

    
    

    enhance diagnostic accuracy.'

  • Awareness of these ossifications reduces surgical risks, especially during skull base and neurosurgical procedures.?

  • Ossified structures, such as the petroclinoid ligament, complicate access to neurovascular structures during surgery.'

  Future Research Directions:

  • Studies using the New Mexico Decedent Imaging Database (NMDID) will quantity correlations between age and specific cranial base ossifications.

  • The NMDID includes over 15,000 decedents (ages 0-100 years) with detailed medical records, offering robust data for research.

  • We hypothesize that ossifications, such as those in the petro-occipital

    
    

    synchondroses, can occur in aging adults with non-degenerative outcomes.'

  • 3D Slicer software will be used to quantify calcifications

    and investigate their correlation with age at death.

  • Findings could enhance the efficacy of cranial osteopathic manipulative medicine, neurology, and neurosurgery for older patients.