Long-Term Morphologic Changes on Sagittal Synostosis Patients Who Underwent a Modified Pi Technique

Direct Occipital Remodeling in Sagittal Synostosis Improves 2-Year Posterior Morphology after Modified Pi Procedure

BACKGROUND

Modifications of the pi craniectomy technique are meant to address the occipital bullet deformity of sagittal synostosis, but it is not clear whether they result in persistent improvement. The authors' purpose was to use morphometric analysis to determine whether a low occipital osteotomy with verticalization results in improved occipital shape after a modified pi procedure 2 years after surgery.

METHOD

The authors performed a retrospective cohort study comparing modified pi technique with and without a low occipital osteotomy with verticalization immediately and 2 years after surgery relative to age-matched normal controls. The authors used anthropometric measures and population-level anatomical templates using the multivariate template construction script from advanced normalization tools for comparison between groups. A subgroup analysis was performed for severe occipital bullet deformity at presentation.

RESULTS

The authors observed stable improvement in the angle of the inferior occiput with the occipital remodeling modification that persisted 2 years after surgery. This improvement was seen in the entire cohort and was greater in the severe subgroup analysis. Complications and blood transfusion volumes were not different between the 2 techniques. The low occipital osteotomy group demonstrated improved posterior vertical height and cephalic index immediately after surgery, but these did not persist 2 years later.

CONCLUSIONS

Occipital remodeling improves the bullet deformity but does not affect posterior vertical height 2 years after surgery. The authors recommend direct inferior occipital remodeling when using the pi technique for young patients with acute occipital incline angles and occipital constriction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

A multi-institutional survey on calvarial vault remodeling techniques for sagittal synostosis and outcomes analysis for patients treated at 12 months and older

OBJECTIVE

Surgical treatment of sagittal craniosynostosis is challenging in older patients. This study aimed to assess the effect of increasing age on open surgical technique selection and patient outcomes using the multi-institutional Synostosis Research Group (SynRG) collaboration.

METHODS

Surgeons in SynRG were surveyed for key influences on their preferred open calvarial vault remodeling techniques at various patient ages: < 6, 6-12, and > 12 months. The SynRG database was then queried for open repairs of nonsyndromic sagittal craniosynostosis performed for patients older than 12 months of age. Perioperative measures, complications, and preoperative and postoperative cephalic indices were reviewed.

RESULTS

All surgeons preferred to treat patients at an earlier age, and most (89%) believed that less-optimal outcomes were achieved at ages older than 12 months. The modified pi procedure was the dominant technique in those younger than 12 months, while more involved open surgical techniques were performed for older patients, with a wide variety of open calvarial vault remodeling techniques used. Forty-four patients met inclusion criteria, with a mean (± SD) age at surgery of 29 ± 16 months. Eleven patients underwent parietal reshaping, 10 parietal-occipital switch, 9 clamshell craniotomy, 7 geometric parietal expansion, 6 modified pi procedure, and 1 parietal distraction. There were no readmissions, complications, or mortality within 30 days postoperatively. Patients' cephalic indices improved a mean of 6.4% ± 4.0%, with a mean postoperative cephalic index of 74.2% ± 4.9%. Differences in postoperative cephalic index (p < 0.04) and hospital length of stay (p = 0.01) were significant between technique cohorts. Post hoc Tukey-Kramer analysis identified the parietal reshaping technique as being significantly associated with a reduced hospital length of stay.

CONCLUSIONS

Patient age is an important driver in technique selection, with surgeons selecting a more involved calvarial vault remodeling technique in older children. A variety of surgical techniques were analyzed, with the parietal reshaping technique being significantly associated with reduced length of stay; however, multiple perioperative factors may be contributory and require further analysis. When performed at high-volume centers by experienced pediatric neurosurgeons and craniofacial surgeons, open calvarial vault techniques can be a safe method for treating sagittal craniosynostosis in older children.

Management of Sagittal and Lambdoid Craniosynostosis: Open Cranial Vault Expansion and Remodeling

The prevalence of sagittal and lambdoid suture craniosynostosis differs considerably, as they are notably the most and least prevalent sutures involved in isolated suture craniosynostosis, respectively. The goals of reconstructing the cranial vault in both entities is the same: to release the fused suture, expand cranial volume, restore normal head shape and morphology, and allow for normal growth of the cranial vault. With regards to sagittal suture synostosis, opinions vary on whether reconstruction should focus on either the anterior or poster cranial vault. In contrast, the poster cranial vault is always targeted in lambdoid suture craniosynostosis.