Multiple operations have been described for the surgical management of nonsyndromic isolated sagittal craniosynostosis, and there remains considerable variation between centers regarding the type and timing of intervention used. Operative techniques used can be broadly divided into open calvarial vault remodeling and minimally invasive techniques. Open calvarial vault remodeling includes total or subtotal calvarial remodeling. Two of the most well-described minimally invasive techniques are endoscopic strip craniectomy with postoperative molding helmet therapy (ESC-H) and spring-assisted cranioplasty (SAC). Minimally invasive techniques have gained popularity in recent years, as there is a growing body of evidence suggesting they are associated with less blood loss, reduced need for blood transfusion, and shorter operative times and hospital stay when compared with open techniques.1 Minimally invasive techniques aim to decrease the invasiveness and morbidity associated with open surgery while maintaining equal functional and cosmetic outcomes.2 Previously published case series have reported perioperative outcomes following both minimally invasive techniques, but a review comparing outcomes between the two minimally invasive techniques is currently lacking in the literature.
The objective of this systematic review was to compare ESC-H with SAC for the surgical management of nonsyndromic single-suture sagittal craniosynostosis.
Methods
Search Strategy and Selection Criteria
This study is reported in accordance with the 2020 PRISMA statement,3 and the study protocol was prospectively registered with the PROSPERO database (registration no. CRD42021234996; https://www.crd.york.ac.uk/prospero/). We included all studies of pediatric patients undergoing either ESC-H or SAC for the management of nonsyndromic single-suture sagittal craniosynostosis. We excluded systematic reviews and meta-analyses, single-patient case reports, mixed cohorts of nonsyndromic and syndromic patients, mixed cohorts of different craniosynostosis types, and studies in which no outcomes of interest were reported. Outcomes of interest included reoperations, blood transfusion, complications, postoperative intensive care unit (ICU) admission, operative time, estimated blood loss, length of hospital stay, and cephalic index.
Studies were identified through a systematic and comprehensive search of the following databases: Embase, MEDLINE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews. Databases were searched from inception to February 19, 2021. The search encompassed terms relating to single-suture sagittal craniosynostosis, ESC-H, and SAC. No language limits were applied to the database search. The full search strategy can be found in Supplementary Data S1.
Data Collection Process
Results from each database were downloaded to reference management software, where duplicates were removed. Two reviewers (A.V., M.C.) independently screened all titles and abstracts for eligibility based on predefined inclusion and exclusion criteria. Eligible full-text articles were screened independently by two reviewers based on predefined criteria. Disagreements were resolved by consensus between the two reviewers or by a third, senior reviewer (A.H.D.S. or G.J.) when consensus could not be reached. Data from the eligible texts were extracted onto a pre-piloted data extraction form. This was performed in duplicate by two reviewers working independently. Any disagreements were resolved by consensus between the two reviewers or by a third, senior reviewer. The references of included texts and relevant reviews were screened for further eligible texts.
We extracted the following information for each study: location, study design, operation type, cohort size, sex, and mean age at surgery. We collected data on the following dichotomous variables: complication rate, need for reoperation, blood transfusion rate, and postoperative ICU admission. We collected summary data (mean and standard deviation or median and interquartile range) on the following continuous variables: operative time, estimated blood loss, length of hospital stay, and cephalic index.
Methodological Quality Assessment
We evaluated the methodological quality of each eligible study using a modified Newcastle-Ottawa Scale.4 Modified Newcastle-Ottawa Scale evaluations were performed independently by two reviewers. Disagreements were resolved by consensus or by a third, senior reviewer. Studies that scored 6–8 points were considered high quality, while studies scoring ≤ 5 points were considered low quality.
Synthesis Methods
If at least 2 studies were identified reporting head-to-head comparisons between operative techniques for any available outcome of interest, we planned to conduct a pairwise meta-analysis, reporting pooled odds ratios for dichotomous variables and standardized mean difference for continuous variables. If insufficient data were available for pairwise meta-analysis, we planned to report pooled summary cohort characteristics for each outcome of interest for both operative techniques. For dichotomous variables, we present the proportion of the cohort with the outcome of interest and compare proportions between surgical technique groups using the N − 1 chi-square test (conducted using MedCalc Software using the comparison of proportions calculator). For continuous variables, we calculated pooled mean and 95% confidence intervals (CIs) for each surgical technique using Stata (version 16, StataCorp), weighted with random effects.
Results
Study Characteristics
Our search yielded 292 articles; following removal of duplicates, 255 articles remained. After abstract screening, 49 articles were selected for full-text screening, and 17 were included in the analysis. We screened the reference list of all included articles for further eligible texts, identifying 5 additional articles for inclusion (Fig. 1). All included studies were either retrospective (n = 21) or prospective (n = 1) observational studies. Table 1 summarizes the included studies.
PRISMA flow diagram. Data added to the PRISMA template (from Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71) under the terms of the Creative Commons Attribution License. Figure is available in color online only.
Summary of included studies
| Authors & Year | Country | Study Design | Operation Type | Cohort Size | Sex | Mean Age (mos) |
|---|---|---|---|---|---|---|
| Berry-Candelario et al., 20115 | USA | Retro | ESC-H | 61 | — | — |
| Bonfield et al., 20186 | Canada | Retro | ESC-H | 34 | — | — |
| Cartwright et al., 20037 | USA | Retro | ESC-H | 107 | 78 M, 29 F | 3.61 |
| Chaichana et al., 20138 | USA | Retro | ESC-H | 9 | — | 2.8 |
| Delye et al., 20169 | Netherlands | Retro | ESC-H | 64 | — | 4 |
| Gociman et al., 201210 | USA | Retro | ESC-H | 46 | 33 M, 13 F | 3.1 |
| Iyer et al., 201711 | USA | Retro | ESC-H | 7 | 6 M, 1 F | 3.5 |
| Jimenez et al., 200212 | USA | Retro | ESC-H | 61 | — | — |
| Magge et al., 201813 | USA | Retro | ESC-H | 62 | — | — |
| Shah et al., 201116 | USA | Retro | ESC-H | 47 | 32 M, 15 F | 3.6 |
| Siddiqi et al., 201114 | USA | Retro | ESC-H | 59 | — | 3 |
| Woerdeman et al., 201215 | Netherlands | Retro | ESC-H | 8 | — | 4.9 |
| Skolnick et al., 202126 | USA | Retro | ESC-H & SAC | 67 (40 ESC-H, 27 SAC) | 29 M, 11 F (ESC-H); 23 M, 4 F (SAC) | 3.0 ESC-H, 4.5 SAC |
| Arko et al., 201517 | USA | Retro | SAC | 22 | — | 4.2 |
| David et al., 201018 | USA | Pro | SAC | 75 | — | 5.7 |
| Esparza & Hinojosa, 200819 | Spain | Retro | SAC | 39 | — | 4.1 |
| Mackenzie et al., 200920 | New Zealand | Retro | SAC | 9 | — | 7 |
| Rodgers et al., 201721 | UK | Retro | SAC | 100 | 77 M, 23 F | 3.1 |
| Runyan et al., 202022 | USA | Retro | SAC | 175 | — | 4.6 |
| Swanson et al., 201623 | USA | Retro | SAC | 5 | — | 3.8 |
| Taylor & Maugans, 201124 | USA | Retro | SAC | 7 | — | 3.7 |
| Wong et al., 201425 | USA | Retro | SAC | 30 | 20 M, 10 F | 4.4 |
Pro = prospective; Retro = retrospective; UK = United Kingdom.
Cohort Characteristics
Overall, 1094 patients were included, with 605 patients (55.3%) undergoing ESC-H and 489 patients (44.7%) undergoing SAC for nonsyndromic sagittal craniosynostosis. Twelve studies5–16 reported outcomes for ESC-H only (n = 565), while 9 studies17–25 reported outcomes for SAC only (n = 462). One study26 compared ESC-H and SAC directly (n = 67 [ESC-H = 40, SAC = 27]). The mean age at surgery was reported by 9 studies for the ESC-H cohort (n = 387) and by 10 studies for the SAC cohort (n = 489). The mean age at surgery for the ESC-H cohort ranged from 2.8 to 4.9 months between studies, while the mean age at surgery for the SAC cohort ranged from 3.1 to 7.0 months between studies. Patient sex was reported in 7 studies (n = 404), with 73.8% (n = 298) being male. Table 1 summarizes the cohort characteristics of all included studies. Four SAC studies17,18,21,22 reported outcomes for the spring removal procedure and are listed in Supplementary Data S4.
Outcomes
Reoperations
Four studies5,9,10,14 reported reoperation rates for the ESC-H cohort (n = 230), with 1.3% of the patients requiring a reoperation. Five studies18,20–22,25 reported reoperation rates for the SAC cohort (n = 389), with 2.3% of the patients requiring a reoperation. The percentage difference (95% CI) between the groups was 1.0% (95% CI −1.7% to 3.2%, p = 0.38; Table 2).
Summary of dichotomous variables
| Variable | ESC-H | SAC | % Difference (95% CI) | p Value | ||||
|---|---|---|---|---|---|---|---|---|
| No. of Studies | No. of Pts | Total w/ Outcome of Interest | No. of Studies | No. of Pts | Total w/ Outcome of Interest | |||
| Reoperations | 4 | 230 | 3 (1.3%) | 5 | 389 | 9 (2.3%) | 1.0% (−1.7% to 3.2%) | 0.38 |
| Blood transfusion | 10 | 448 | 54 (12.1%) | 4 | 377 | 8 (2.1%) | 10.0% (6.6% to 13.5%) | <0.0001 |
| Complication rate | 7 | 283 | 12 (4.2%) | 6 | 423 | 28 (6.6%) | 2.4% (−1.2% to 5.7%) | 0.18 |
| Postop ICU admission | 2 | 98 | 5 (5.1%) | 2 | 250 | 0 (0.0%) | 5.1% (1.8% to 11.4%) | 0.0003 |
Pts = patients.
Blood Transfusion Rate
The blood transfusion requirement was reported by 10 studies7–12,14–16,26 for the ESC-H cohort (n = 448), with 12.1% requiring intraoperative blood transfusion. Four studies18,21,22,26 reported the blood transfusion requirement for the SAC cohort (n = 377), and 2.1% required intraoperative blood transfusion. The ESC-H cohort had a significantly higher blood transfusion rate. The percentage difference between the groups was 10.0% (95% CI 6.6%–13.5%, p < 0.0001; Table 2).
Complication Rate
The complication rate was reported in 7 studies5,8,10–12,14,26 for the ESC-H cohort (n = 283), with 4.2% experiencing postoperative complications. Six studies18,19,21,22,24,26 reported complication rates for the SAC cohort (n = 423) and 6.6% experienced postoperative complications. The percentage difference between the groups was 2.4% (95% CI −1.2% to 5.7%, p = 0.18; Table 2). Specific complications reported by each study are listed in Supplementary Data S3.
Postoperative ICU Admission
The postoperative ICU admission requirement was reported by 2 studies6,9 for the ESC-H cohort (n = 98), with 5.1% requiring postoperative ICU admission. Two studies18,22 reported postoperative ICU admission for the SAC cohort (n = 250), and none (0%) of the patients required postoperative ICU admission. The percentage difference between the groups was 5.1% (95% CI 1.8%–11.4%, p = 0.0003; Table 2).
Operative Time
Operative time was reported by 4 studies8,9,11,26 for the ESC-H cohort (n = 120), with a pooled mean of 77.5 minutes (95% CI 64.1–90.9 minutes), and by 4 studies21,22,24,26 for the SAC cohort (n = 309), with a pooled mean of 60.3 minutes (95% CI 49.1–71.5 minutes; Table 3, Fig. 2).
Summary of continuous variables
| Variable | ESC-H | SAC | ||||
|---|---|---|---|---|---|---|
| No. of Studies | No. of Pts | Overall Pooled Mean Estimate (95% CI) | No. of Studies | No. of Pts | Overall Pooled Mean Estimate (95% CI) | |
| Op time (mins) | 4 | 120 | 77.5 (64.1–90.9) | 4 | 309 | 60.3 (49.1–71.5) |
| Length of stay (days) | 4 | 120 | 1.7 (0.7–2.6) | 3 | 209 | 1.4 (1.3–1.5) |
| Estimated blood loss (ml) | 3 | 80 | 32.3 (26.6–38.0) | 2 | 197 | 35.3 (4.5–66.1) |
| Cephalic index preop | 3 | 101 | 69.1 (66.7–71.6) | 6 | 334 | 69.4 (67.6–71.1) |
| Cephalic index postop | 3 | 101 | 75.9 (72.0–79.9) | 6 | 334 | 75.0 (73.0–76.9) |
Graph showing the mean operative time (shaded) and 95% CI (black line) as reported in the SAC and ESC-H groups.
Length of Stay
Length of stay was reported by 4 studies8,9,11,26 for the ESC-H cohort (n = 120), with a pooled mean of 1.7 days (95% CI 0.7–2.6 days), and by 3 studies22,24,26 for the SAC cohort (n = 209), with a pooled mean of 1.4 days (95% CI 1.3–1.5 days; Table 3, Fig. 3).
Graph showing the mean length of stay (shaded) and 95% CI (black line) as reported in the SAC and ESC-H groups.
Estimated Blood Loss
Estimated blood loss was reported by 3 studies8,9,11 for the ESC-H cohort (n = 80), with a pooled mean of 32.3 ml (95% CI 26.6–38.0 ml), and by 2 studies17,22 for the SAC cohort (n = 197), with a pooled mean of 35.3 ml (95% CI 4.5–66.1 ml; Table 3, Fig. 4).
Graph showing the mean estimated blood loss (shaded) and 95% CI (black line) as reported in the SAC and ESC-H groups.
Cephalic Index
Cephalic index was reported by 3 studies9,11,26 for the ESC-H cohort (n = 101), with a pooled mean of 69.1 (95% CI 66.7–71.6) preoperatively and a pooled mean of 75.9 (95% CI 72.0–79.9) postoperatively (Table 3). The difference between the pooled means pre- and postoperatively was 6.8 (95% CI 0.37–13.22; Fig. 5). Six studies17,21–24,26 reported cephalic index for the SAC cohort (n = 334), with a pooled mean of 69.4 (95% CI 67.6–71.1) preoperatively and a pooled mean of 75.0 (95% CI 73.0–76.9) postoperatively (Table 3). The difference between the pooled means pre- and postoperatively was 5.6 (95% CI 1.9–9.3; Fig. 5).
Graph showing the mean difference in cephalic index preoperatively versus postoperatively (shaded) and 95% CI (black line) as reported in the SAC and ESC-H groups.
Methodological Quality Assessment
The Newcastle-Ottawa Scale assessment of methodological quality can be found in the Supplementary Data S2. Overall, 3 (13.6%) of the 22 studies were considered high quality and 19 (86.4%) were considered low quality.
Discussion
ESC-H was described by Jimenez and Barone in 1998,27 and SAC was first reported by Lauritzen et al. in 1998.28 Although both surgical techniques were first described in 1998, they are considered relatively novel with limited data reported in the literature. The theoretical advantage of these techniques is reducing perioperative morbidity while achieving equally good functional and cosmetic results. Both techniques rely on the fact that the infant skull is in a rapid growth phase, and may have the advantage, as early operations, of preventing progressive cranial deformity.29
With any surgical technique, there are also inherent disadvantages. For ESC-H, there are concerns about the economic and appointment burden of postoperative orthotic therapy. Regarding economic burden, ESC-H appears to be associated with lower hospital costs overall compared with open techniques.30,31 Helmet therapy is inevitably associated with more frequent outpatient clinic appointments as the orthoses require frequent checks and adjustments, and the effectiveness of postoperative orthotic therapy is dependent on patient compliance. Studies have demonstrated that the requirement for a second operation is higher in patients who do not tolerate or are poorly compliant with the helmet.29 For SAC, a drawback is the requirement of a second surgery to remove the springs. Despite spring removal surgery being a relatively minor procedure, there remain risks, including those associated with general anesthesia.31,32 Future studies comparing outcomes between ESC-H and SAC should include data from the spring removal procedure, as this may contribute to additional morbidity and healthcare costs. In addition, a risk of under-correction occurring in a small percentage of children undergoing SAC for the surgical correction of sagittal craniosynostosis has been reported.33
In the present systematic review, when analyzing the dichotomous variables of interest, ESC-H was associated with a higher rate of blood transfusions compared with the SAC group. Potential surgical factors that may contribute to this difference include the following: 1) ESC-H requiring more bone removal, which may therefore result in more bleeding intraoperatively; and 2) controlling bleeding using direct cautery is more challenging given the nature of endoscopic surgery. However, it should be noted that the threshold for blood transfusion may vary based on hospital policy or local guidelines, which may influence the results.
There was no significant difference in the proportion of patients with reoperations between the ESC-H and SAC groups. Although there was no significant difference, SAC was associated with a slightly higher complication rate. Surgical factors affecting this higher rate may include a risk of implant-related complications (e.g., implant failure or infection) with the SAC technique. In the ESC-H group, helmets may be in situ for up to 6 months; thus, complications may not appear within the observation period, and therefore may be missed by case series with limited follow-up periods. ESC-H was associated with a higher rate of postoperative ICU admission, which may be influenced by preplanned ICU admission in accordance with local guidelines or hospital policy. This influence may confound true differences relating to postoperative clinical status.
Mean point estimates differ between the ESC-H and SAC groups for the continuous variables of interest, but the overlapping CIs indicate that there is no significant difference between the pooled estimates for operative time, length of stay, estimated blood loss, and cephalic index. Operative time may be influenced by the learning curve associated with performing endoscopic surgery. Operator experience and volume of endoscopic surgery performed may strongly influence operative time. Length of stay may be influenced by hospital protocol or local guidelines. Differences in cephalic index pre- versus postoperatively may be affected by the potential for postoperative treatment adjustment with the helmet used in the ESC-H group.
Given that data were pooled from studies analyzing individual techniques, and thus no pairwise meta-analysis (with odds ratios and mean difference calculations) was possible, these data must be interpreted with caution and merely as hypothesis generating. The literature comparing the two techniques is minimal, with only one case series directly comparing the two surgical techniques.26 Skolnick et al. demonstrated that both procedures appear to be equally safe, with 40 patients in the ESC-H group and 27 in the SMC group.26 Both techniques resulted in minimal blood transfusions, short operative times, and short hospital stays. The ESC-H cohort showed greater cephalic index improvement compared to the SAC cohort. However, follow-up data were limited to 2 years postoperatively; therefore, no conclusions regarding long-term anthropometric outcomes could be made.
Limitations
There were several limitations to this review. The available data in the literature regarding the two procedures remain relatively scarce. The majority of the included studies were retrospective and of low methodological quality. Because we were unable to conduct traditional pairwise meta-analysis, we could not quantify statistical heterogeneity, although it is likely that there is significant heterogeneity between studies included in this review. Potential sources of heterogeneity may be hospital protocols regarding blood transfusion, ICU admission criteria, and types of complications reported. It is vital for future studies to use an internationally accepted complication reporting system specific to craniofacial surgery, to allow for valid comparison and data synthesis. Additionally, due to the short-term follow-up in the included studies, long-term anthropometric outcomes could not be compared between the two procedures.
Conclusions
This systematic review demonstrates that the current literature does not show superiority of either ESC-H or SAC, and outcomes are broadly similar for the treatment of nonsyndromic sagittal craniosynostosis. However, the evidence is limited by single-center retrospective studies of low methodological quality. Given clinical equipoise, there is a need for international multicenter trials to provide definitive and generalizable data. Pragmatic collaborative trial design, such as cluster randomized trials of hospitals, may be a feasible approach.
Acknowledgments
Dr. James holds an MRC Clinical Academic Research Programme grant (no. MR/T005297/1). This research was supported by the GOSH Charity (award no. 12SG15) and the National Institute for Health Research (NIHR) GOSH/UCL Biomedical Research Centre Advanced Therapies for Structural Malformations and Tissue Damage pump-prime funding call (grant no. 17DS18). This report incorporates independent research for the NIHR Biomedical Research Centre Funding Scheme. The views expressed in this publication are those of the authors and not necessarily those of the National Health Service, the National Institute for Health, or the United Kingdom Department of Health.
Disclosures
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
Author Contributions
Conception and design: Valetopoulou, James, Silva. Acquisition of data: Valetopoulou, Constantinides. Analysis and interpretation of data: Valetopoulou, Constantinides, James, Silva. Drafting the article: Valetopoulou, Constantinides. Critically revising the article: Valetopoulou, James, Silva. Reviewed submitted version of manuscript: all authors. Statistical analysis: Valetopoulou, Constantinides. Administrative/technical/material support: Valetopoulou, Eccles, Ong, Hayward, Dunaway, Jeelani, Silva. Study supervision: James, Silva.
Supplemental Information
Online-Only Content
Supplemental material is available with the online version of the article.
Supplementary Data. https://thejns.org/doi/suppl/10.3171/2022.7.PEDS2232.
References
- 1↑
Goyal A, Lu VM, Yolcu YU, Elminawy M, Daniels DJ. Endoscopic versus open approach in craniosynostosis repair: a systematic review and meta-analysis of perioperative outcomes. Childs Nerv Syst. 2018;34(9):1627–1637.
- 2↑
Delye HHK, Borstlap WA, van Lindert EJ. Endoscopy-assisted craniosynostosis surgery followed by helmet therapy. Surg Neurol Int. 2018;9:59.
- 3↑
Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372(71):n71.
- 4↑
Wells GA, Shea B, O’Connell D, et al. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. Ottawa Hospital Research Institute. Accessed July 8, 2022. http://www.ohri.ca/programs/clinicalepidemiology/oxford.asp
- 5↑
Berry-Candelario J, Ridgway EB, Grondin RT, Rogers GF, Proctor MR. Endoscope-assisted strip craniectomy and postoperative helmet therapy for treatment of craniosynostosis. Neurosurg Focus. 2011;31(2):E5.
- 6↑
Bonfield CM, Basem J, Cochrane DD, Singhal A, Steinbok P. Examining the need for routine intensive care admission after surgical repair of nonsyndromic craniosynostosis: a preliminary analysis. J Neurosurg Pediatr. 2018;22(6):616–619.
- 7↑
Cartwright CC, Jimenez DF, Barone CM, Baker L. Endoscopic strip craniectomy: a minimally invasive treatment for early correction of craniosynostosis. J Neurosci Nurs. 2003;35(3):130–138.
- 8↑
Chaichana KL, Jallo GI, Dorafshar AH, Ahn ES. Novel use of an ultrasonic bone-cutting device for endoscopic-assisted craniosynostosis surgery. Childs Nerv Syst. 2013;29(7):1163–1168.
- 9↑
Delye HHK, Arts S, Borstlap WA, et al. Endoscopically assisted craniosynostosis surgery (EACS): the craniofacial team Nijmegen experience. J Craniomaxillofac Surg. 2016;44(8):1029–1036.
- 10↑
Gociman B, Marengo J, Ying J, Kestle JRW, Siddiqi F. Minimally invasive strip craniectomy for sagittal synostosis. J Craniofac Surg. 2012;23(3):825–828.
- 11↑
Iyer RR, Uribe-Cardenas R, Ahn ES. Single incision endoscope-assisted surgery for sagittal craniosynostosis. Childs Nerv Syst. 2017;33(1):1–5.
- 12↑
Jimenez DF, Barone CM, Cartwright CC, Baker L. Early management of craniosynostosis using endoscopic-assisted strip craniectomies and cranial orthotic molding therapy. Pediatrics. 2002;110(1 Pt 1):97–104.
- 13↑
Magge SN, Lajthia O, Keating RF, Myseros JS, Oluigbo CO, Rogers GF. Minimally invasive endoscopic strip craniectomy for craniosynostosis: outcome data of 100 consecutive cases. Childs Nerv Syst. 2018;34:2022–2023.
- 14↑
Siddiqi F, Bollo R, Kestle J. Endoscopic-assisted strip craniectomy for non-syndromic sagittal synostosis. Childs Nerv Syst. 2011;27(10):1770.
- 15↑
Woerdeman P, Han S, Verwer B, Muradin M, Stubenitsky B. Endoscopy-assisted versus open repair of sagittal craniosynostosis: the Utrecht experience. Childs Nerv Syst. 2012;28(5):793.
- 16↑
Shah MN, Kane AA, Petersen JD, Woo AS, Naidoo SD, Smyth MD. Endoscopically assisted versus open repair of sagittal craniosynostosis: the St Louis Children’s Hospital experience. J Neurosurg Pediatr. 2011;8(2):165–170.
- 17↑
Arko L IV, Swanson JW, Fierst TM, et al. Spring-mediated sagittal craniosynostosis treatment at the Children’s Hospital of Philadelphia: technical notes and literature review. Neurosurg Focus. 2015;38(5):E7.
- 18↑
David LR, Plikaitis CM, Couture D, Glazier SS, Argenta LC. Outcome analysis of our first 75 spring-assisted surgeries for scaphocephaly. J Craniofac Surg. 2010;21(1):3–9.
- 19↑
Esparza J, Hinojosa J. Complications in the surgical treatment of craniosynostosis and craniofacial syndromes: apropos of 306 transcranial procedures. Childs Nerv Syst. 2008;24(12):1421–1430.
- 20↑
Mackenzie KA, Davis C, Yang A, MacFarlane MR. Evolution of surgery for sagittal synostosis: the role of new technologies. J Craniofac Surg. 2009;20(1):129–133.
- 21↑
Rodgers W, Glass GE, Schievano S, et al. Spring-assisted cranioplasty for the correction of nonsyndromic scaphocephaly: a quantitative analysis of 100 consecutive cases. Plast Reconstr Surg. 2017;140(1):125–134.
- 22↑
Runyan CM, Gabrick KS, Park JG, et al. Long-term outcomes of spring-assisted surgery for sagittal craniosynostosis. Plast Reconstr Surg. 2020;146(4):833–841.
- 23↑
Swanson JW, Haas JA, Mitchell BT, et al. The effects of molding helmet therapy on spring-mediated cranial vault remodeling for sagittal craniosynostosis. J Craniofac Surg. 2016;27(6):1398–1403.
- 24↑
Taylor JA, Maugans TA. Comparison of spring-mediated cranioplasty to minimally invasive strip craniectomy and barrel staving for early treatment of sagittal craniosynostosis. J Craniofac Surg. 2011;22(4):1225–1229.
- 25↑
Wong L, Thompson A, Sanger C, et al. Early experience with 30 cases of endoscopic spring assisted surgery for sagittal craniosynostosis. Cleft Palate Craniofac J. 2014;51(3):157.
- 26↑
Skolnick GB, Yu JL, Patel KB, et al. Comparison of 2 sagittal craniosynostosis repair techniques: spring-assisted surgery versus endoscope-assisted craniectomy with helmet molding therapy. Cleft Palate Craniofac J. 2021;58(6):678–686.
- 27↑
Jimenez DF, Barone CM. Endoscopic craniectomy for early surgical correction of sagittal craniosynostosis. J Neurosurg. 1998;88(1):77–81.
- 28↑
Lauritzen C, Sugawara Y, Kocabalkan O, Olsson R. Spring mediated dynamic craniofacial reshaping. Case report. Scand J Plast Reconstr Surg Hand Surg. 1998;32(3):331–338.
- 29↑
Jimenez DF, Barone CM. Endoscopic technique for sagittal synostosis. Childs Nerv Syst. 2012;28(9):1333–1339.
- 30↑
Chan JWH, Stewart CL, Stalder MW, St Hilaire H, McBride L, Moses MH. Endoscope-assisted versus open repair of craniosynostosis: a comparison of perioperative cost and risk. J Craniofac Surg. 2013;24(1):170–174.
- 31↑
Kung TA, Vercler CJ, Muraszko KM, Buchman SR. Endoscopic strip craniectomy for craniosynostosis: do we really understand the indications, outcomes, and risks? J Craniofac Surg. 2016;27(2):293–298.
- 32↑
David LR, Proffer P, Hurst WJ, Glazier S, Argenta LC. Spring-mediated cranial reshaping for craniosynostosis. J Craniofac Surg. 2004;15(5):810–818.
- 33↑
Lauritzen CGK, Davis C, Ivarsson A, Sanger C, Hewitt TD. The evolving role of springs in craniofacial surgery: the first 100 clinical cases. Plast Reconstr Surg. 2008;121(2):545–554.
