Discussion: Minimally Invasive, Spring-Assisted Correction of Sagittal Suture Synostosis
The authors previously reported their outcomes using extended strip craniectomy without helmet or springs that yielded shorter operative times and less blood loss than cranial vault remodeling, but a 9 percent risk for developing papilledema after surgery compared with 7 percent after cranial vault remodeling.1,2 Of equal significance was the finding that 9 percent of patients who underwent cranial vault remodeling at age 11.3 months demonstrated papilledema before surgery versus 2 percent of patients undergoing sagittal strip at age 4.8 months.1,2 These findings provided compelling evidence for their approach using spring-assisted cranioplasty to maintain the advantages of decreased morbidity and earlier surgery to decrease preoperative and postoperative papilledema.
Like the Great Ormond Street Hospital unit, the authors used a modified approach using two parasagittal osteotomies, leaving a central strip of bone in the midline to protect the sagittal sinus.3–5 The authors “tailor” the midline strip of bone to allow upward bending to facilitate remodeling, whereas the Great Ormond Street Hospital unit performed a 15 × 15-mm craniectomy to facilitate remodeling of the vault.5 The width between the osteotomies varied between 1 and 4 cm, and the width of the strip may vary between the front and back to meet desired changes in head shape, whereas the Great Ormond Street Hospital unit used a uniform width of strip.5 The impact of these variables on the final outcome is difficult to assess, and this highlights the heterogeneity in technique that must be considered when making comparisons of variations in “strip” procedures.
The greatest value of this study is the internal control provided for open cranial vault remodeling from the authors’ previous reports. Compared with their cranial vault remodeling outcomes, patients treated with the minimally invasive spring-assisted strip craniectomy experienced less blood loss (90 percent less than cranial vault remodeling), a shorter duration of surgery, fewer dural tears, and equivalent rates of reoperation.2 The cephalic index improved from 66.7 preoperatively to 75.2 postoperatively, and stabilized at 72 at 49 to 60 months of age, comparable to their cranial vault remodeling outcomes. The complications reported were few and on par with their cranial vault remodeling outcomes. Papilledema occurred in 2.4 percent of patients postoperatively, compared with 7 percent in the cranial vault remodeling group.2 Based on the uniform metrics used and comparison with their own experience with cranial vault remodeling, the minimally invasive spring-assisted strip craniectomy procedure demonstrated less morbidity and comparable or superior functional efficacy compared to cranial vault remodeling at the time of follow-up.
Neurocognitive outcomes were not reported in this study.