Is decompensation preoperatively a risk in Lenke 1C curves?

Area of Science:

• Orthopedic surgery
• Spinal deformities
• Adolescent idiopathic scoliosis (AIS)

Background:

• Lenke 1C curves in adolescent idiopathic scoliosis (AIS) are associated with coronal decompensation.
• Limited data exists on the relationship between preoperative and postoperative coronal decompensation in Lenke 1C curves.
• The impact of selective thoracic fusion (STF) on coronal decompensation in these patients requires further investigation.

Purpose of the Study:

• To analyze the distribution of coronal decompensation in Lenke 1C curves before and after surgery.
• To evaluate the effect of selective thoracic fusion (STF) on coronal decompensation outcomes.
• To identify factors influencing postoperative coronal decompensation in Lenke 1C AIS.

Main Methods:

• Prospective analysis of a multicenter registry of patients with Lenke 1C adolescent idiopathic scoliosis (AIS) undergoing surgical treatment.
• Patients were categorized preoperatively as decompensated (C7-CSVL > 2 cm) or balanced (C7-CSVL within 2 cm).
• Comparison of coronal balance outcomes between selective thoracic fusion (STF) and nonselective fusion groups at 2-year follow-up.

Main Results:

• Preoperative coronal balance in Lenke 1C patients skewed leftward (-17 ± 13 mm).
• A significant proportion of patients undergoing STF who were preoperatively decompensated remained decompensated postoperatively (57%).
• Nonselective fusions demonstrated superior coronal balance at 2 years (89%) compared to STF (46-57% balanced), irrespective of preoperative status.

Conclusions:

• Lenke 1C adolescent idiopathic scoliosis (AIS) patients frequently exhibit preoperative leftward coronal decompensation.
• Selective thoracic fusion (STF) in decompensated Lenke 1C curves often leads to persistent moderate coronal decompensation.
• Nonselective fusion of both thoracic and lumbar curves results in better 2-year coronal balance than STF for Lenke 1C AIS.