Selecting the Substantially Touched Vertebra as the Lowest Instrumented Vertebra in Spinal Surgeries for B3GALT6-Related Disorders: Clinical Experience and Literature Review

Abstract

Objectives: B3GALT6-related disorders are characterized by severe early-onset spinal deformities requiring surgical corrections but are associated with increased risks of perioperative complications. This study reports the clinical experience and outcomes of selecting the substantially touched vertebra (STV) as the lowest instrumented vertebra (LIV) in spinal surgeries for patients with B3GALT6-related disorders, a group of extremely rare skeletal and connective tissue disorders.

Methods: This retrospective study included patients who were molecularly diagnosed with B3GALT6-related disorders and received spinal surgeries for (kypho)scoliosis between 2017 and June 2023. Their medical records were reviewed. We also conducted a systematic literature review to identify (kypho)scoliosis management in patients with B3GALT6-related disorders.

Results: We identified a total of four patients. Patient 1 presented with severe kyphoscoliosis and segmentation defects and received a pedicle subtraction osteotomy with short fusion and dual growing rods from T3 to L3. However, coronal imbalance was observed at the 18-month follow-up. Genetic testing revealed biallelic disease-causing variants in B3GALT6. A revision surgery was successfully performed, with the level of the LIV extended to the STV (L4). The LIV was similarly extended to the STV in the index surgery for subsequent Patients 2 and 3 who received preoperative genetic testing results, and no complication has been observed. Patient 4 underwent preoperative Halo-pelvic traction to minimize complications, followed by posterior spinal fusion. The curves were successfully reduced without complications. A systematic literature review identified 86 articles reporting (kypho) scoliosis management in 12 of the 63 patients with B3GALT6-related disorders. Limited surgical experience has been reported, with an increased rate of complications, including death.

Conclusions: Selecting the STV as the LIV is recommended in spinal surgeries for patients with B3GALT6-related disorders, considering the characteristic joint hypermobility associated with the condition. Additionally, preoperative Halo-pelvic traction may also be safe and effective. Furthermore, preoperative molecular diagnosis is essential for enabling precision medicine and minimizing complications.

Keywords: Ehlers‐Danlos syndrome; genetic testing; joint instability; operative; scoliosis; surgical procedures.