Long-Term Characterization of Cranial Defects After Surgical Correction for Single-Suture Craniosynostosis

Reossification of Bone Defects After Surgical Correction of Nonsyndromic Craniosynostosis: A Review and An Original Study

BACKGROUND AND OBJECTIVES

Surgical correction of nonsyndromic craniosynostosis (NSC) aims to restore cranial shape. Reossification of bone defects is paramount for the best aesthetic prognosis. However, the literature on the quantitative evaluation of bone defects after NSC surgery is scarce. This study aimed to quantify and analyze the surface area of bone defects after NSC surgery and establish a threshold value for predicting persistent defects.

METHODS

We conducted a systematic review and a prospective study of 28 children undergoing surgical treatment for NSC. We analyzed 426 defects on the first computed tomography scan (1 year postoperative) and 132 defects on the second computed tomography scan (4.6 years postoperative). Statistical analysis was performed using Spearman's rank correlation coefficient, Mann-Whitney-Wilcoxon rank-sum test, and Youden's J statistic.

RESULTS

Our systematic review identified three studies reporting on bone defects' surface area and reossification rate. In our study, we found no statistically significant differences in the number or size of defects between sex or type of NSC. The threshold value for the surface area of bone defects above which there was a higher probability of persistent defects was 0.19 cm2 (Youden point), with an 89.47 % probability of persistence. Defects with a surface area below 0.19 cm2 had a considerably lower probability, only 15.07%, of persistence over time.

CONCLUSION

Our study provides valuable quantitative data for managing bone defects after NSC surgery. Defects with a surface area above 0.19 cm2 should be monitored with radiological imaging because of the risk of persistence. Our findings highlight the importance of developing robust and reproducible methods for the quantitative analysis of bone defects after NSC surgery.

Early bone reformation after cranial vault remodelling for sagittal craniosynostosis: A retrospective 3D analysis

This study aims to measure postoperative bone reformation percentage, rates and patterns after cranial vault remodelling (CVR) in isolated non-syndromic sagittal craniosynostosis. Volumetric bone measurements were performed starting from the DICOM files of previously available postoperative CT scans. The 3D images were then resampled into the master box, and 'Skull 3D models' were derived. The percentage of bone reformation was investigated using automated 3D analysis software. The intra-rater reliability analysis revealed high reliability (Intraclass correlation coefficient = 0.99, p < 0.001). The median bone reformation volume and rate were 11.2 ml and 1.98 ml/week, respectively. The median percentage of bone reformation was 56.7% when the median postoperative CT timing was 6.1 weeks. As a statistic model, the linear plateau showed the highest Pseudo R² in both volume and percentage of bone reformation predicting patterns. By using the calculated model at 9 weeks postoperatively, the re-osteogenesis reaches 80% of the total cranial defect. After CVR, the early bone reformation pattern was demonstrated as a linear plateau model rather than logarithmic. This study gives a better understanding of the pattern and quantity of re-osteogenesis at cranial defects after CVR. The statistic model can facilitate healthcare practitioners to predict bone reformation and improve postoperative care protocol in sagittal craniosynostosis management.

A preliminary analysis of replicating the biomechanics of helmet therapy for sagittal craniosynostosis

PURPOSE

The aim of this study was to investigate the biomechanics of endoscopically assisted strip craniectomy treatment for the management of sagittal craniosynostosis while undergoing three different durations of postoperative helmet therapy using a computational approach.

METHODS

A previously developed 3D model of a 4-month-old sagittal craniosynostosis patient was used. The strip craniectomy incisions were replicated across the segmented parietal bones. Areas across the calvarial were selected and constrained to represent the helmet placement after surgery. Skull growth was modelled and three variations of helmet therapy were investigated, where the timings of helmet removal alternated between 2, 5, and 8 months after surgery.

RESULTS

The predicted outcomes suggest that the prolonging of helmet placement has perhaps a beneficial impact on the postoperative long-term morphology of the skull. No considerable difference was found on the pattern of contact pressure at the interface of growing intracranial volume and the skull between the considered helmeting durations.

CONCLUSION

Although the validation of these simulations could not be performed, these simulations showed that the duration of helmet therapy after endoscopically assisted strip craniectomy influenced the cephalic index at 36 months. Further studies require to validate these preliminary findings yet this study can lay the foundations for further studies to advance our fundamental understanding of mechanics of helmet therapy.

Computed Tomography in Patients With Craniosynostosis: A Survey to Ascertain Practice Patterns Among Craniofacial Surgeons

BACKGROUND

In patients with craniosynostosis, imaging remains up to the discretion of the plastic surgeon or neurosurgeon. To inform best practice guidelines, we sought to obtain data surrounding the frequency at which craniofacial surgeons order computed tomography (CT), as well as indications. We hypothesized that we would identify considerable variation in both imaging and associated indications.

METHODS

We surveyed members of the American Society of Maxillofacial Surgeons and the American Society of Craniofacial Surgeons to measure the frequency of preoperative and postoperative head CTs, as well as indications. Initial items were piloted with 2 craniofacial surgeons and 1 neurosurgeon, using interviews to ensure content validity. χ2 Tests were used to measure associations between operative volume, years in practice, and imaging.

RESULTS

Eighty-five craniofacial surgeons responded (13.8% response rate), with the majority (63.5%) having performed a craniosynostosis operation in the last month. Only 9.4% of surgeons never order preoperative CTs. Of those who do, the most common indications included diagnosis confirmation (31.2%) and preoperative planning (27.3%). About 25% of surgeons always obtain postoperative head CTs, usually to evaluate surgical outcomes (46.7%). Only 13.3% of respondents order 2 or more postoperative scans. Higher operative volume was associated with a lower likelihood of ordering preoperative head CTs (P = 0.008).

CONCLUSIONS

The majority of surgeons obtain preoperative head CTs, whereas only 25% obtain CTs postoperatively, often to evaluate outcomes. Because outcomes may be evaluated clinically, this is a poor use of resources and exposes children to radiation. Consensus guidelines are needed to create best practices and limit unnecessary studies.

Vascularized Pericranial Flap as a Method to Prevent Persistent Skull Defects After Craniectomy for Sagittal Synostosis

ABSTRACT

Some cranial defects resulting from sagittal craniectomy for craniosynostosis never completely close and require cranioplasty. This study evaluates the results of 2 methods to minimize such defects: (1) trapezoidal craniectomy that is narrower posteriorly (2) vascularized pericranial flap that is sewn to the dura under a rectangular craniectomy.Children who underwent primary open sagittal craniectomy with biparietal morcellation (with/without frontal cranioplasty) for single-suture nonsyndromic sagittal synostosis from 2013 through 2018 were included. Children were excluded if there was a dural tear, if they had no 1-year follow-up, or if they had unmeasured and/or uncounted skull defects. Surgeries were divided into (1) standard craniectomy, (2) trapezoidal craniectomy, or (3) craniectomy with pericranial flap. Differences in percentage of children with defects and mean total defect area 1 year postsurgery were compared between the 3 groups.We reviewed 148 cases. After exclusions, 34 of 53 children (64%) who underwent standard craniectomy, 6 of 17 children (35%) who had pericranial flaps, and 5 of 11 children (46%) who underwent trapezoidal craniectomy had defects 1 year postsurgery. The percentage of children with defects (P = 0.0364) but not the defect area was significantly higher in the standard craniectomy than in the pericranial flap group. The percentage of subjects with defects was not significantly different between the standard and the trapezoidal craniectomy groups.Sewing a vascularized pericranial flap to the dura at the craniectomy site may protect against persistent bony defects after sagittal craniectomy for craniosynostosis. Longer follow-up is needed to determine if this technique leads to lower rates of cranioplasty.

Sport participation and related head injuries following craniosynostosis correction: a survey study

OBJECTIVE

Craniosynostosis (CS) affects about 1 in 2500 infants and is predominantly treated by surgical intervention in infancy. Later in childhood, many of these children wish to participate in sports. However, the safety of participation is largely anecdotal and based on surgeon experience. The objective of this survey study was to describe sport participation and sport-related head injury in CS patients.

METHODS

A 16-question survey related to child/parent demographics, CS surgery history, sport history, and sport-induced head injury history was made available to patients/parents in the United States through a series of synostosis organization listservs, as well as synostosis-focused Facebook groups, between October 2019 and June 2020. Sports were categorized based on the American Academy of Pediatrics groupings. Pearson's chi-square test, Fisher's exact test, and the independent-samples t-test were used in the analysis.

RESULTS

Overall, 187 CS patients were described as 63% male, 89% White, and 88% non-Hispanic, and 89% underwent surgery at 1 year or younger. The majority (74%) had participated in sports starting at an average age of 5 years (SD 2.2). Of those participating in sports, contact/collision sport participation was most common (77%), and 71% participated in multiple sports. Those that played sports were less frequently Hispanic (2.2% vs 22.9%, p < 0.001) and more frequently had undergone a second surgery (44% vs 25%, p = 0.021). Only 9 of 139 (6.5%) sport-participating CS patients suffered head injuries; 6 (67%) were concussions and the remaining 3 were nondescript but did not mention any surgical needs.

CONCLUSIONS

In this nationwide survey of postsurgical CS patients and parents, sport participation was exceedingly common, with contact sports being the most common sport category. Few head injuries (mostly concussions) were reported as related to sport participation. Although this is a selective sample of CS patients, the initial data suggest that sport participation, even in contact sports, and typically beginning a few years after CS correction, is safe and commonplace.

A Comparison of Subgaleal Versus Subperiosteal Dissection in Open Cranial Vault Expansion for Sagittal Craniosynostosis

BACKGROUND

The aim of this study was to evaluate surgical outcomes for patients with sagittal craniosynostosis undergoing open cranial vault remodeling with a modified pi procedure comparing subgaleal versus subperiosteal dissection.

METHODS

A retrospective chart review was performed for children between the ages of 3 and 7 months with sagittal craniosynostosis undergoing open cranial vault expansion at Seattle Children's Hospital. Patient demographics, operative variables, and postoperative outcomes including the surface area of bony cranial defects at 2-year follow-up were evaluated.

RESULTS

Over a 3-year period, 35 patients between the ages of 3 and 7 months underwent surgical correction of sagittal craniosynostosis using our institutional adaptation of the modified pi technique. Twenty-five patients underwent exposure via a subgaleal (SG) approach, 10 patients had a subpericranial (SP) exposure. Compared with the SP group, the SG group had significant lower estimated blood loss and a shorter operating time (P < 0.05). There were no significant differences with regard to hospital length of stay or postoperative complications (P ≥ 0.48). At 2 years postoperatively, there were no significant differences in the size of the largest cranial defects (SG: 1.1 ± 0.1 cm² versus 3.7 ± 0.1 cm², P = 0.40); no patients required a secondary cranioplasty.

CONCLUSIONS

Open posterior and middle cranial vault expansion is a safe and efficient method of open cranial vault expansion in sagittal craniosynostosis regardless of the plane of dissection. Elevation of the scalp flaps in the SG plane is a minor technical modification that can reduce blood loss and operative times.