● major alignment objectives (most valid for age 50–60 years): LL = PI ± 9°, PT < 20°, SVA < 5 cm
Definition of adult degenerative scoliosis:
Adult degenerative scoliosis is a spinal deformity with Cobb angle > 10 º 1) in a skeletally mature individual 2). in a skeletally mature individual. ADS may be the result of childhood idiopathic scoliosis persisting into adulthood, or maybe de novo.
This condition also goes by the name, “de novo” scoliosis. As the name implies, this variety begins in the adult patient due to degeneration of the discs, arthritis of the adjacent facet joints and collapse and wedging of the disc spaces.
A survey of neurosurgeon AANS membership assessed the deformity knowledge base and impact of current training, education, and practice experience to identify opportunities for improved education. Eleven questions developed and agreed upon by experienced spinal deformity surgeons tested ASD knowledge and were subgrouped into 5 categories:
1) radiology/spino-pelvic alignment
2) health-related quality of life
3) surgical indications
4) operative technique
5) clinical evaluation.
Chi-square analysis was used to compare differences based on participant demographic characteristics (years of practice, spinal surgery fellowship training, percentage of practice comprising spinal surgery).
Responses were received from 1456 neurosurgeons. Of these respondents, 57% had practiced less than 10 years, 20% had completed a spine fellowship, and 32% devoted more than 75% of their practice to spine. The overall correct answer percentage was 42%. Radiology/spinal pelvic alignment questions had the lowest percentage of correct answers (38%), while clinical evaluation and surgical indications questions had the highest percentage (44%). More than 10 years in practice, completion of a spine fellowship, and more than 75% spine practice were associated with greater overall percentage correct (p < 0.001). More than 10 years in practice was significantly associated with increased percentage of correct answers in 4 of 5 categories. Spine fellowship and more than 75% spine practice were significantly associated with increased percentage correct in all categories. Interestingly, the highest error was seen in risk for postoperative coronal imbalance, with a very low rate of correct responses (15%) and not significantly improved with fellowship (18%, p = 0.08).
The results of this survey suggest that ASD knowledge could be improved in neurosurgery. Knowledge may be augmented with neurosurgical experience, spinal surgery fellowships, and spinal specialization.
In 1994 Dubousset 4) described the concept of “cone of economy” which is a range of spinal alignment in which a minimum of muscle activity is required to maintain balance. Quantification of severity of spinal deformity and classification helps guide appropriate treatment paradigms.
A literature analysis highlighted several classification schemes developed for degenerative scoliosis patients: the Simmons classification system, the Aebi system, the Faldini working classification system, the Schwab system, and the Scoliosis Research Society system 5).
ADS tends to progress at an average rate of 3° per year (range: 1–6°). Factors associated with higher rates of progression: Cobb angle > 30°, apical rotation > Grade II (on the Nash-Moe system, which is falling into disuse), lateral listhesis > 6 mm, and an intercrest line through L5. Factors not correlated with rate of progression: age and gender. Controversial associations: osteopenia.
High-Frequency Spinal Cord Stimulation for the Treatment of Primarily Axial Back Pain due to Degenerative Scoliosis with Spinopelvic Imbalance 6).