Letter to “Rod Contour Angle and Postoperative Thoracic Kyphosis: Key Predictors of Proximal Junctional Kyphosis in Pediatric Neuromuscular Scoliosis After Spinopelvic Fusion”

Dear Editor

We read with great interest the article by Shen et al ¹ on proximal junctional kyphosis (PJK) in nonambulatory pediatric neuromuscular scoliosis (NMS) patients following spinopelvic fusion. The authors provide valuable insights into the incidence, risk factors, and clinical implications of PJK in this vulnerable population. However, we would like to raise several points for further discussion and consideration.

First, while the study identifies key radiographic predictors of PJK, such as rod contour angle (RCA) and postoperative T2-T12 kyphosis, the clinical applicability of these findings warrants further exploration. For instance, the authors suggest optimizing RCA intraoperatively to reduce PJK risk. However, how feasible is it to achieve precise RCA adjustments in the context of severe spinal deformities often seen in NMS patients? Given the variability in surgical techniques and instrumentation, could the authors elaborate on specific intraoperative strategies to achieve optimal RCA without compromising other surgical goals, such as curve correction or pelvic balance?

Second, the study highlights the importance of preoperative proximal junctional angle (PJA) as a predictor of PJK, with lower preoperative PJA values (<4.5°) associated with increased risk. This finding raises a question: should patients with low preoperative PJA undergo additional preoperative interventions, such as bracing or physical therapy, to improve cervical and thoracic alignment before surgery? Furthermore, could the authors clarify whether preoperative PJA is modifiable through surgical planning, or is it primarily a fixed anatomical parameter?

Third, the study defines PJK based on radiographic criteria (PJA ≥10° and an increase of ≥10° from baseline). While this definition is widely accepted, it may not fully capture the functional and clinical impact of PJK in NMS patients, who often have limited mobility and unique functional demands. For example, how does PJK affect sitting balance, respiratory function, or caregiver burden in this population? Incorporating patient-reported outcomes or caregiver assessments could provide a more comprehensive understanding of the clinical significance of PJK in NMS patients.^2,3

Fourth, the authors report that no revision surgeries were performed for PJK in their cohort, possibly due to reduced functional demands and compensatory wheelchair adjustments. While this finding is noteworthy, but whether the absence of revision surgeries reflects a true lack of clinical impact or an underestimation of the burden of PJK. Could the authors provide more details on how PJK-related complications, such as pain or progressive deformity, were managed non-surgically? Additionally, would earlier detection and intervention for PJK, such as through routine follow-up imaging, improve long-term outcomes in this population?

In conclusion, Shen et al have made a significant contribution to our understanding of PJK in NMS patients.