Perioperative Outcomes in the Treatment of Isolated Sagittal Synostosis: Cranial Vault Remodeling Versus Spring Mediated Cranioplasty

A coddling of the sagittal suture: inequality in spring-assisted expansion

PURPOSE

We examined differences in long-term morphometric outcomes of spring-mediated cranioplasty (SMC) for various forms of isolated nonsyndromic sagittal craniosynostosis.

METHODS

A retrospective review was performed of children who underwent SMC from 2011 to 2020 at the Children's Hospital of Philadelphia. Cephalic indices (CI), Whitaker grades, parietal bone thickness, and degree of suture fusion were assessed. Frontal bossing and vertex-nasion-opisthocranion (VNO) angles were compared to a normal control group.

RESULTS

Fifty-four subjects underwent surgery at age 3.6 ± 1.0 months with follow-up of 6.3 ± 1.8 years. Mean CI was 75.2 ± 4.1 at 5.9 ± 2.0 years postoperatively. Mean CI were 75.8 ± 4.1 (n = 32), 76.4 ± 4.0 (n = 22), and 77.1 ± 4.8 (n = 11) at 5, 7, and 9+ years postoperatively, respectively. Three (5.6%) required reoperation for persistent scaphocephalic cranial deformity. Fifty-one (94.4%) were Whitaker Grade I. On physical examination, 12 (22.2%) demonstrated craniofacial abnormalities. At long-term follow-up, there were no differences in frontal bossing angle (102.7 ± 5.2 degrees versus 100.7 ± 5.6 degrees, p = .052) and VNO angle (44.9 ± 3.3 degrees versus 43.9 ± 2.2 degrees, p = .063) between study and control groups. Younger age at surgery predicted a lower Whitaker grade, more normalized VNO angle, and greater change in CI during active expansion. Increased percentage fused of the posterior sagittal suture predicted a higher Whitaker grade, while decreased anterior fusion was associated with frontal bossing and temporal hollowing.

CONCLUSIONS

Overall, children undergoing spring-mediated cranioplasty for sagittal craniosynostosis demonstrated maintenance of CI, favorable cosmetic outcomes, and a low reoperation rate at mid-term follow-up. Early intervention is associated with improved aesthetic outcomes, and regional fusion patterns may influence long-term craniofacial dysmorphology.

Intracranial Pressure Patterns in Children with Sagittal Craniosynostosis

BACKGROUND

Elevated intracranial pressure (ICP) in sagittal craniosynostosis has a wide spectrum of reported incidence, and patterns are not well understood across infancy and childhood. Characterizing the natural history of ICP in this population may clarify risks for neurocognitive delay and inform treatment decisions.

METHODS

Infants and children with sagittal craniosynostosis and unaffected control subjects were prospectively evaluated with spectral-domain optical coherence tomography from 2014 to 2021. Elevated ICP was determined based on previously validated algorithms using retinal optical coherence tomography parameters.

RESULTS

Seventy-two patients with isolated sagittal craniosynostosis and 25 control subjects were evaluated. Overall, 31.9% ( n = 23) of patients with sagittal craniosynostosis had evidence of ICP greater than or equal to 15 mmHg, and 27.8% ( n = 20) of patients had ICP greater than or equal to 20 mmHg. Children with sagittal craniosynostosis younger than 6 months were more likely to have normal ICP (88.6% <15 mmHg; 91.4% <20 mmHg) than those aged between 6 and 12 months (54.5%, P = 0.013; 54.5%, P = 0.005) than those older than 12 months (46.2%, P < 0.001; 53.8%, P = 0.001). ICP was directly correlated with severity of scaphocephaly ( P = 0.009). No unaffected control subjects at any age exhibited retinal thickening suggestive of elevated ICP.

CONCLUSION

Elevated ICP is rare in isolated sagittal craniosynostosis younger than 6 months, but it becomes significantly more common after 6 months of age, and may correlate with severity of scaphocephaly.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Spring forces and calvarial thickness predict cephalic index changes following spring-mediated cranioplasty for sagittal craniosynostosis

BACKGROUND

Variables interacting to predict outcomes following spring-mediated cranioplasty (SMC) for non-syndromic craniosynostosis, including spring parameters and calvarial thickness, are poorly understood. This study assessed interactions between spring parameters and calvarial thickness to predict changes in cephalic index (CI) following SMC.

METHODS

Patients undergoing SMC for non-syndromic sagittal craniosynostosis at our institution between 2014 and 2021 were included. Calvarial thickness was determined from patient preoperative CTs using Materalise Mimics at 27 points in relation to the sagittal suture. Linear mixed effects models were used to determine interactions between anterior, middle, and posterior calvarial thickness with spring force and length.

RESULTS

Sixty-nine patients undergoing surgery at mean age 3.7 months were included in this study. Stronger posterior spring force interacted with thinner posterior calvarial thickness to predict greater changes in CI at 3 months postoperatively (p = 0.022). When evaluating spring force and calvarial thickness set distances from the sagittal suture, stronger posterior spring force interacted with thinner posterior calvarial thickness 5 mm (p = 0.043) and 10 mm (p = 0.036) from the sagittal suture to predict changes in CI. Interactions between spring parameters and calvarial thickness in the anterior and middle positions did not significantly predict changes in CI.

CONCLUSIONS

Stronger posterior spring force interacted with thinner posterior calvaria to predict greater changes in CI 3 months following SMC for non-syndromic sagittal craniosynostosis. These results suggest dynamic interactions between several variables may impact outcomes following SMC.

Management of Sagittal and Lambdoid Craniosynostosis: Minimally Invasive Approaches

The resurgence of strip craniectomies began in the mid-1990s with advances in surgical technique and anesthesia coupled with the critical observation that earlier interventions benefitted from an easily molded skull. Jimenez and Barone's pioneering introduction of endoscopic approaches to strip craniectomies coupled with postoperative helmeting in newborns and young infants and Claes Lauritzen's introduction of spring-mediated cranioplasty began the era of minimally invasive approaches in the surgical correction of craniosynostosis. This article provides technical descriptions of these treatment modalities, a comparative literature review, and our institutional algorithms for the correction of sagittal craniosynostosis and unilambdoid craniosynostosis.

Syndromic Craniosynostosis: Cranial Vault Expansion in Infancy

Syndromic craniosynostosis (CS) represents a relatively uncommon disease process that poses significant reconstructive challenges for the craniofacial surgeon. Although there is considerable overlap in clinical features associated with various forms of syndromic CS, key extracranial features and close examination of the extremities help to distinguish the subtypes. While Virchow's law can easily guide the diagnosis of single suture, nonsyndromic CS, syndromic CS traditionally results in atypical presentations inherent to multiple suture fusion. Coronal ring involvement in isolation or associated with additional suture fusion is the most common pattern in syndromic CS often resulting in turribrachycephaly.

Neurocognitive outcomes of children with non-syndromic single-suture craniosynostosis

While the focus of craniosynostosis surgery is to improve head shape, neurocognitive sequelae are common and are incompletely understood. Neurodevelopmental problems that children with craniosynostosis face include cognitive and language impairments, motor delays or deficits, learning disabilities, executive dysfunction, and behavioral problems. Studies have shown that children with multiple suture craniosynostosis have more impairment than children with single-suture craniosynostosis. Children with isolated single-suture subtypes of craniosynostosis such as sagittal, metopic, and unicoronal craniosynostosis can have distinct neurocognitive profiles. In this review, we discuss the unique neurodevelopmental profiles of children with single-suture subtypes of craniosynostosis.

Parietal bone thickness for predicting operative transfusion and blood loss in patients undergoing spring-mediated cranioplasty for nonsyndromic sagittal craniosynostosis

OBJECTIVE

Variables that can predict outcomes in patients with craniosynostosis, including bone thickness, are important for surgical decision-making, yet are incompletely understood. Recent studies have demonstrated relative risks and benefits of surgical techniques for correcting head shape in patients with nonsyndromic sagittal craniosynostosis. The purpose of this study was to characterize the relationships between parietal bone thickness and perioperative outcomes in patients who underwent spring-mediated cranioplasty (SMC) for nonsyndromic sagittal craniosynostosis.

METHODS

Patients who underwent craniectomy and SMC for nonsyndromic sagittal craniosynostosis at a quaternary pediatric hospital between 2011 and 2021 were included. Parietal bone thickness was determined on patient preoperative CT at 27 suture-related points: at the suture line and at 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm from the suture at the anterior parietal, midparietal, and posterior parietal bones. Preoperative skull thickness was compared with intraoperative blood loss, need for intraoperative transfusion, and hospital length of stay (LOS).

RESULTS

Overall, 124 patients with a mean age at surgery ± SD of 3.59 ± 0.87 months and mean parietal bone thickness of 1.83 ± 0.38 mm were included in this study. Estimated blood loss (EBL) and EBL per kilogram were associated with parietal bone thickness 0.5 cm (ρ = 0.376, p < 0.001 and ρ = 0.331, p = 0.004; respectively) and 1.0 cm (ρ = 0.324, p = 0.007 and ρ = 0.245, p = 0.033; respectively) from the suture line. Patients with a thicker parietal bone 0.5 cm (OR 18.08, p = 0.007), 1.0 cm (OR 7.16, p = 0.031), and 1.5 cm (OR 7.24, p = 0.046) from the suture line were significantly more likely to have undergone transfusion when controlling for age, sex, and race. Additionally, parietal bone thickness was associated with hospital LOS (β 0.575, p = 0.019) when controlling for age, sex, and race. Patient age at the time of surgery was not independently associated with these perioperative outcomes.

CONCLUSIONS

Parietal bone thickness, but not age at the time of surgery, may predict perioperative outcomes including transfusion, EBL, and LOS. The need for transfusion and EBL were most significant for parietal bone thickness 0.5 cm to 1.5 cm from the suture line, within the anticipated area of suturectomy. For patients undergoing craniofacial surgery, parietal bone thickness may have important implications for anticipating the need for intraoperative transfusion and hospital LOS.

Spring-mediated cranioplasty versus endoscopic strip craniectomy for sagittal craniosynostosis

OBJECTIVE

Endoscopic strip craniectomy (ESC) and spring-mediated cranioplasty (SMC) are two minimally invasive techniques for treating sagittal craniosynostosis in early infancy. Data comparing the perioperative outcomes of these two techniques are sparse. Here, the authors hypothesized that outcomes would be similar between patients undergoing SMC and those undergoing ESC and conducted a study using the multicenter Pediatric Craniofacial Surgery Perioperative Registry (PCSPR).

METHODS

The PCSPR was queried for infants under the age of 6 months who had undergone SMC or ESC for sagittal synostosis. SMC patients were propensity score matched 1:2 with ESC patients on age and weight. Primary outcomes were transfusion-free hospital course, intensive care unit (ICU) admission, ICU length of stay (LOS), and hospital length of stay (HLOS). The authors also obtained data points regarding spring removal. Comparisons of outcomes between matched groups were performed with multivariable regression models.

RESULTS

The query returned data from 676 infants who had undergone procedures from June 2012 through September 2019, comprising 580 ESC infants from 32 centers and 96 SMC infants from 5 centers. Ninety-six SMC patients were matched to 192 ESC patients. There was no difference in transfusion-free hospital course between the two groups (adjusted odds ratio [aOR] 0.78, 95% CI 0.45-1.35). SMC patients were more likely to be admitted to the ICU (aOR 7.50, 95% CI 3.75-14.99) and had longer ICU LOSs (incident rate ratio [IRR] 1.42, 95% CI 1.37-1.48) and HLOSs (IRR 1.28, 95% CI 1.17-1.39).

CONCLUSIONS

In this multicenter study of ESC and SMC, the authors found similar transfusion-free hospital courses; however, SMC infants had longer ICU LOSs and HLOSs. A trial comparing longer-term outcomes in SMC versus ESC would further define the roles of these two approaches in the management of sagittal craniosynostosis.