History of Management of Spinal Lipoma in Children

Understanding of Disease

• 1857 — First description: The history of spinal lipomas can be traced to 1857, when Johnson documented a child exhibiting a fatty tumor in the sacral region (5).
• 1971 — First use of terminology: The term “spinal lipoma” was introduced to the medical lexicon by Rogers in 1971 (6).
• 1982 — First classification system: In 1982, Chapman proposed a structured classification of dysraphic lipomas, dividing them into three anatomical subtypes based on their relationship to the conus: dorsal, transitional, and caudal (1,2).
• 2010 — Modification of existing classification system: In 2010, Pang added a further subtype: chaotic, in which the lipoma extends beyond the dorsal root entry zone of the spinal cord/conus (2).
• 2018 — New classification based on embryogenesis: In 2018, Morata et al. added a new classification scheme based on the embryonic changes seen during primary and secondary neurulation (7).
• 2024 — Spinal lipomas added to list of spinal dysraphic disorders: In 2024, Orphanet online database of rare diseases (https://www.orpha.net/en/disease/classification) revised the classification of spinal dysraphic disorders, including spinal lipomas (39). The classification is based on essential clinical and radiological features rather than embryogenesis.

Technological Development

Imaging

• Early 1980s — MRI widely available: As MRI equipment became widely available for clinical use in the early 1980s, it quickly became the modality of choice for evaluating spinal lipomas (43,44).
• Late 1980s — FAT-saturation MRI techniques introduced: FAT-SAT (fat-saturation) MRI techniques were introduced in the late 1980s to better delineate fat-containing lesions, including lipomas. Fat, which appears bright on regular T1 images, loses signal and becomes dark on fat-suppressed images. In addition to helping distinguish a lipoma from other types of lesions, FAT-SAT also helps delineate the interface between spine, neural tissue, and fat (45).
• Late 1990s and early 2000s — 3D-CISS MRI developed: In the late 1990s and early 2000s, the development of 3D-CISS MRI provided better visualization of the spinal cord and nerve roots. CISS MRI enables submillimeter spatial resolution and provides high contrast between CSF and soft-tissues, such as fat, which improves the delineation of a lipoma’s anatomy (46,47).

Electrophysiological monitoring

• 1980s — Use of cystometrography more common: Urodynamic studies, including CMG, have been in use since the 1970s, but their application to spinal dysraphism-related bladder dysfunction became more common in the 1980s (48,49). CMG is a means of studying bladder compliance and sphincter pressure. It is a useful diagnostic tool in patients with lower urinary tract symptoms (31). Unlike cystoscopy, which can diagnose lower tract abnormalities, a CMG can determine whether the urological issue is related to an upper motor neuron problem, including spinal cord tethering (8).
• Late 1980s to early 1990s — Widespread use of IOM: IOM became integral in the safe removal of spinal lipomas by the mid-1990s. This involves monitoring the motor pathways to lower limb muscles and sphincters to map nerve roots through direct spinal cord and nerve root stimulation. Monitoring of the BCR is used in some centers to evaluate the afferent and efferent pathways responsible for sphincter function (40).

Surgical Technique

• 1980s to 1990s — Conventional approach involves subtotal resection: The conventional surgical treatment of conus region lipomas evolved during the 1980s and 1990s. It comprises the detachment of the lipoma from the dura, followed by subtotal resection of the lipoma, leaving a variable thickness of lipoma over the placode to reduce the risk of intraoperative injury to the terminal spinal cord and roots. Although this technique has a low risk of neurological injury, late deterioration due to retethering is reported in up to 25% of cases (9).
• 1990s to approximately 2010 — Recent advances in total/near-total resection techniques: A recent development is the concept of total/near-total resection by Pang et al. (2,10). This method has demonstrated a progression-free survival rate of 90% and a complication rate of less than 5% (2).