A craniometric analysis of posterior cranial vault distraction osteogenesis

Free-floating bone flap posterior cranial vault release in syndromic craniosynostosis

The aim of this study was to investigate the efficacy of non-detachable free-floating bone flap posterior cranial vault release (FFBF-PCVR) in syndromic craniosynostosis. A retrospective review was completed of subjects who underwent FFBF-PCVR at 4 time-points: within 3 months preoperatively, 7 days postoperatively, 3 months postoperatively and at the last follow-up postoperatively. Volumetric and craniometric data, the ratio of ventricular diameter, and the cerebellar tonsillar descent were measured after FFBF-PCVR by using computed tomographic and magnetic resonance imaging. A total of 19 patients underwent FFBF-PCVR. The mean age was 11.7 months (range 4-36 months). The mid cranial height, posterior cranial height, and anterior posterior diameter length significantly increased from preoperative to postoperative 7 days, from postoperative 7 days to postoperative3 months, and from postoperative 3 months to the last follow-up. There was a significant increase in pre- to 7 days postoperative intracranial volume (1195.21 ± 246.56 cm³, p < 0.001; respectively), 3 months postoperative intracranial volume (1228.03 ± 249.61 cm³, p < 0.001; respectively), and intracranial volume at last follow-up (1390.25 ± 219.99 cm³, p < 0.001; respectively). There was a significant increase in 7 days' postoperative to 3 months' postoperative intracranial volume (p < 0.001; respectively), and intracranial volume at last follow-up (p < 0.001; respectively). There was a significant increase in 3 months postoperative to intracranial volume at last follow-up (p < 0.001). The mean intracranial volume increased by an average of 36.6 percent (range, 18.1 to 79.2 percent) at last follow-up. The degree of hydrocephalus in the preoperative child was (45.77% ± 9.17%), and at the last follow-up after surgery, the degree of hydrocephalus was (35.02 ± 9.50%), p < 0.01). Preoperatively, 14 patients (73.7 percent) had radiographic evidence of Chiari malformation type I. The cerebellar tonsillar descent, measured using pre- and postoperative MRI, decreased in all patients after FFBF-PCVR (preoperative: 7.5 ± 1.4 mm, postoperative: 5.3 ± 1.7 mm; p = 0.001). FFBF-PCVR can efficiently expand the posterior cranial vault with only one surgical procedure. Moreover, it helps to relieve hydrocephalus and cerebellar tonsillar herniation.

Vaulting further: cranial vault expansion for craniocerebral disproportion without primary craniosynostosis

PURPOSE

Treatment of subjects with refractory idiopathic intracranial hypertension (IIH) or shunted hydrocephalus with chronic shunt complications is challenging. What is the role for cranial vault expansion, particularly utilizing posterior vault distraction osteogenesis (PVDO), in these cases? This study assesses medium-term efficacy of cranial vault expansion in this unique patient population.

METHODS

A retrospective review was conducted of patients who underwent cranial vault expansion from 2008 to 2023 at the Children's Hospital of Philadelphia. Subjects who did not have a diagnosis of primary craniosynostosis were included in the study. Demographic information, medical history, and perioperative details were collected from medical records. Primary outcomes were the rate of CSF diversion procedures and resolution of presenting signs and symptoms. Secondary outcomes were perioperative and 90-day complications and reoperation requirement.

RESULTS

Among 13 included subjects, nine (69.2%) patients had a primary diagnosis of shunted hydrocephalus and 4 (30.8%) patients had IIH. Twelve (92.3%) subjects underwent posterior vault distraction osteogenesis (PVDO) and one (7.7%) underwent posterior vault remodeling (PVR). All 4 patients with IIH demonstrated symptomatic improvement following PVDO, including resolution of headaches, vomiting, and/or papilledema. Among 9 patients with shunted hydrocephalus, CSF diversion requirement decreased from 2.7 ± 1.6 procedures per year preoperatively to 1.2 ± 1.8 per year following cranial vault expansion (p = 0.030). The mean postoperative follow-up was 4.1 ± 2.1 years and four (30.8%) patients experienced complications within 90 days of surgery, including infection (n = 2), CSF leak (n = 1), and elevated ICP requiring lumbar puncture (n = 1). Four (30.8%) patients underwent repeat cranial vault expansion for recurrence of ICP-related symptoms. At most recent follow-up, 7 of 9 patients with shunted hydrocephalus demonstrated symptomatic improvement.

CONCLUSION

Cranial vault expansion reduced intracranial hypertension-related symptomology as well as the rate of CSF diversion-related procedures in patients with refractory IIH and shunted hydrocephalus without craniosynostosis, and should be considered in those who have significant shunt morbidity.

Success of Bone Ossification After Posterior Vault Distraction Osteogenesis in Patients With Craniosynostosis

BACKGROUND

Posterior vault distraction osteogenesis (PVDO) is an effective treatment for multisuture and syndromic craniosynostosis. It remains unclear how well the calvarium ossifies after PVDO, especially in older patients when they have plateaued in their cranial growth phase. The purpose of this study is to report outcomes associated with PVDO across a wide range of ages at our institution.

METHODS

Operative details, distraction parameters, complications, and details of cranioplasty, if applicable, were obtained for all patients who underwent PVDO between March 2016 and July 2022. The surface areas of distraction sites and residual cranial defects were measured from computed tomography scans after a consolidation phase, and the percentages of the distraction regions with ossification were subsequently calculated.

RESULTS

Fifteen patients underwent PVDO at a mean age of 5.1 years (0.5-18.7 y). The mean percentage of ossification among all patients was 80.4% (59.1%-95.3%). The degree of ossification was not significantly associated with age at the time of surgery at the univariate level (Pearson-r=-0.15, P=0.573). Three patients (20.0%) required titanium mesh cranioplasty for definitive reconstruction, which was significantly more likely in patients who were >4 years old at the time of PVDO (P=0.04).

CONCLUSIONS

Complete ossification of the distracted area of the cranium is unlikely after PVDO. Ossification appears less robust with increasing age, although not statistically significant in our study population, likely due to the limited sample size. Future studies should assess the role of age, latency period, and distraction rate in minimizing residual defects.

Early posterior vault distraction osteogenesis changes the syndromic craniosynostosis treatment paradigm: long-term outcomes of a 23-year cohort study

BACKGROUND

Early surgical management of syndromic craniosynostosis varies widely between centers, with patients typically undergoing multiple intracranial procedures through childhood. This study evaluates the long-term impact of early posterior vault distraction osteogenesis (PVDO) versus conventional treatment paradigms on the number and timing of subsequent craniofacial procedures.

METHODS

We retrospectively analyzed the longitudinal operative patterns of patients with syndromic craniosynostosis treated from 2000 to 2023 with greater than five years of follow-up. Outcomes of patients who underwent early PVDO and conventional vault reconstruction were compared.

RESULTS

Fifty-five patients met the inclusion criteria (30 PVDO and 25 conventional). Age at initial vault surgery was similar between the PVDO and conventional cohorts (7.6 vs. 8.8 months), as were baseline craniometrics (p > 0.05). Multiple fronto-orbital advancement (FOA) procedures were performed in only 1/30 (3%) PVDO-treated patient versus 12/25 (48%) conventionally-treated patients (p < 0.001). Twelve (40%) PVDO-treated patients did not undergo FOA at all. Among patients with Apert and Crouzon syndromes, fewer PVDO-treated patients required FOA prior to midface surgery (33% vs. 92%, p = 0.004) or repeat FOA (6% vs. 50%, p = 0.005) compared to conventionally-treated patients. Among patients with Muenke and Saethre-Chotzen syndromes, a similar proportion of patients required FOA in the PVDO and conventional cohorts (91% vs. 100%, p = 0.353), though no PVDO-treated patients required repeat FOA (0% vs. 44%, p = 0.018).

CONCLUSIONS

Early PVDO is associated with a reduction in the high burden of both FOA and, critically, revisionary frontal procedures which are commonly seen in conventionally-treated patients with syndromic craniosynostosis.

Posterior Cranial Distraction in Craniosynostosis: A Systematic Review of the Literature

OBJECTIVE

Posterior cranial distraction (PCD) is a surgical technique to address craniosynostosis, especially in syndromic patients. The technique has the ability to significantly expand the cranium, while requiring minimal dural dissection, compared to cranial remodeling. Our goals were to determine the patient characteristics and surgical outcomes of PCD. The two questions that we sought to answer were: 1) What is the average published complication rate and the most common complications of PCD? and 2) How much intracranial volume expansion can one expect with PCD?

DESIGN

A PubMed database search of articles on PCD was performed. Case reports and articles with overlapping patients were excluded. A systematic review was performed using the remaining articles.

MAIN OUTCOME MEASURES

Patient data were extracted in order to determine the total number of patients, patients with a syndrome, types of syndromes, mean age at surgery, mean distraction distance, mean increase in intracranial volume, and complications.

RESULTS

18 articles representing 325 patients were analyzed. A syndrome was present in 68.6% of patients. The mean age at time of surgery was 22.1 months. Mean distraction amount was 24.7 mm. Mean increase in intracranial volume was 253.2 cm3. The overall complication rate was 32.2%, with the most common complications being surgical-site infection, hardware-related complications and delayed wound healing.

CONCLUSIONS

PCD is a powerful technique in the management of syndromic craniosynostosis, although complication rates are significantly higher than traditional remodeling techniques. Future studies should compare the effects of supratorcular and infratorcular osteotomies on intracranial volume, cosmesis and complications.

Long-term sequelae of normocephalic pansynostosis: a rare but insidious entity

OBJECTIVE

Patients with normocephalic pansynostosis, who have a grossly normal head shape, are often overlooked early in life and present late with elevated intracranial pressure (ICP) requiring timely cranial vault expansion. This study evaluates the long-term clinical outcomes of patients with normocephalic pansynostosis.

METHODS

We retrospectively reviewed patients with a clinical and radiographic diagnosis of primary pansynostosis who underwent vault reconstruction between 2000 and 2023. Clinical and treatment course after craniofacial interventions was followed in patients with normocephaly to assess outcomes.

RESULTS

Thirty-five patients with primary pansynostosis were identified, of which eight (23.5%) had normocephaly and underwent initial vault expansion at a mean age of 5.0 ± 2.4 years. All eight patients (50.0% male) presented with symptoms of elevated ICP including headaches (50.0%), nausea and vomiting (50.0%), and developmental delay (62.5%) and/or signs of elevated ICP including papilledema (75.0%) and radiologic thumbprinting on head computed tomography scan (87.5%). Three of the four normocephalic patients who had over 7 years of postoperative follow-up developed subjective headaches, vision changes, or learning and behavioral issues in the long-term despite successful vault reconstruction.

CONCLUSIONS

Our longitudinal experience with this rare but insidious entity demonstrates the importance of timely intervention and frequent postoperative monitoring, which are critical to limiting long-term neurological sequelae. Multidisciplinary care by craniofacial surgery, neurosurgery, ophthalmology, and neuropsychology with follow-up into adolescence are recommended to assess for possible recurrence of elevated ICP secondary to cranio-cerebral disproportion.

The Top 100 Most-Cited Publications in Clinical Craniofacial Research

INTRODUCTION

Craniosynostosis is a birth defect defined as premature closure of sutures leading to possible neurological deficits and cosmetic deformities. Most of the current literature to date focuses on craniosynostosis etiology by analyzing genetics. This paper is a bibliometric analysis of the most influential works related to the clinical management of craniosynostosis to help guide clinicians in their decision-making.

METHODS AND MATERIALS

Clarivate Web of Science database was used to identify the top 100 most-cited articles addressing the clinical management of craniosynostosis. A bibliometric review was performed to analyze publication metrics and track research trends.

RESULTS

The 100 most-cited publications pertaining to craniosynostosis management were cited a cumulative 12,779 times. The highest cited article was Shillito and colleagues' "Craniosynostosis: A Review Of 519 Surgical Patients" with 352 citations. The oldest clinical craniosynostosis article dates back to 1948, and the most recent was published in 2016. The year with the most clinical-focused publications was 2011. The most prolific author was Renier, D. The United States produced 56 of the 100 articles. Most articles (n=52) were level 3 evidence.

DISCUSSION

This bibliometric evaluation of craniosynostosis provides insight into the most impactful literature on this topic. The highest cited articles retrospectively analyze large sample sizes, outline proper evaluation, discuss intervention timelines, and highlight specific treatment plans for this birth defect. By filtering through existing literature, this analysis can guide clinicians on the management of craniosynostosis to maximize patient outcomes.

Posterior Vault Distraction in the Acute Setting

ABSTRACT

Posterior vault distraction osteogenesis (PVDO) has been shown to resolve acute intracranial hypertension (AIH) while carrying an acceptable perioperative morbidity profile. PVDO has been associated with symptomatic improvement and fewer surgeries in those requiring ventriculoperitoneal shunts. The authors' experience using PVDO as an acute intervention is presented, demonstrating its safety and efficacy for management of AIH. Four cases of children with craniosynostosis that underwent PVDO in the acute setting are outlined. All patients presented with papilledema and symptoms of AIH. One patient with slit ventricle syndrome (SVS) presented with a nonfunctioning shunt following multiple shunt revisions. No intraoperative complications during distractor placement or removal were reported. Distraction protocol for all patients began on postoperative day 1 at 1-2 mm per day, resulting in an average total distraction of 30.25 mm. For the 3 cases with no shunt, the average length of stay was 7 days. As part of the planned treatment course, the patient with SVS required externalization of the shunt during distraction followed by early distractor removal and planned shunt replacement. One case of surgical site infection (in an immunocompromised patient) required premature distractor removal during the consolidation period. Computed tomography (CT) in all patients indicated increased intracranial volume following distraction, and symptomatic improvement was reported. Six-month follow-up showed resolution of papilledema in all patients. The authors' experience using PVDO in the acute setting is reported, alongside a review of current literature, in order to provide supporting evidence for the efficacy of PVDO as a tool for resolving AIH.

Determination of Novel, Cranium-Based Relationships for Construct Placement in Microtia Reconstruction for Hemifacial Microsomia Patients

OBJECTIVE

Determine if the ideal location of the construct in microtia reconstruction for hemifacial microsomia (HFM) can be more accurately derived from measurements on the cranium.

DESIGN

High-resolution computerized tomography (CT) images were analyzed through craniometric linear relationships.

SETTING

Our tertiary care institution from 2000 to 2021.

PATIENTS/PARTICIPANTS

Patients diagnosed with HFM and microtia, who had high-resolution craniofacial CT scans, yielding 36 patients accounting for 44 CT scans.

MAIN OUTCOME MEASURE(S)

First, the integrity of the posterior cranial vault among HFM patients was determined. If proven to be unaffected, it could be used as a reference in the placement of the construct. Second, the position of the ear in relation to the cranium was assessed in healthy age-matched controls. Third, if proven to be useful, the concordance of these cranium-based relationships could be validated among our HFM cohort.

RESULTS

The posterior cranial vault is unaffected in HFM (P > .001). Further, craniometric relationships between the tragus and the Foramen Magnum, as well as between the tragus and the posterior cranium, have been shown to be highly similar and equally precise in predicting tragus position in healthy controls (P > .001). These relationships held true across all age groups (P > .001), and importantly among HFM patients, where the mean absolute difference in predicted tragus position never surpassed 1.5 mm.

CONCLUSIONS

Relationships between the tragus and the cranium may be used as an alternative to distorted facial anatomy or surgeon's experience to assist in pre-operative planning of construct placement in microtia reconstruction for HFM patients.

Posterior cranial vault distraction in children with syndromic craniosynostosis: the era of biodegradable materials-a comprehensive review of the literature and proposed novel global application

Distraction osteogenesis is utilized to increase intracranial volume in the treatment of restrictive pathologies, most commonly syndromic synostosis. Children too young for open calvarial vault expansion or other systemic or local contraindications to a direct reconstructive approach benefit greatly from distraction osteogenesis, typically addressing posterior vault expansion. Wound infection, cerebrospinal fluid (CSF) leak, device failure, need for a second surgery for removal, and cost, are issues that can limit the use of this approach. These challenges are more pronounced in low- and middle-income countries (LMICs) due to lack of access to the device, the financial burden of the need for a second surgery, and the severity of the implications of infection and CSF leak. Over the last five decades, there has been an increased acceptance of bioresorbable instrumentation in craniofacial surgery. Poly L-lactic acid, polyglycolic acid, and polydioxanone are the most commonly used polymers. New resorbable fixation tools such as ultrasound-activated pins and heat-activated pins are superior to conventional bioresorbable screws in allowing attachment to thinner bone plates. In this paper, we present a review of the literature on cranial vault distraction and the use of bioresorbable materials and propose a novel design of a fully absorbable cranial distractor system using external magnetic distraction control, eliminating the need for external activation ports and a second surgery to remove the hardware. The application of this technology in LMIC settings could advance access to care and treatment options for patients with syndromic synostosis.

Syndromic Craniofacial Disorders

This article reviews the most common craniofacial syndromes encountered in clinical practice. Key physical features of each condition are highlighted to aid in accurate recognition and diagnosis. Optimal individualized treatment approaches are discussed.

Morphometric analysis and outcomes following posterior cranial vault distraction in syndromic and multisuture craniosynostosis

BACKGROUND

Turribrachycephaly is a common feature in many syndromic and multisuture craniosynostoses and is traditionally treated with total cranial vault reshaping and fronto-orbital advancement. A staged approach with posterior cranial vault distraction as a primary procedure followed by anterior cranial vault reshaping has the advantage of reducing the vertical dimension of the skull in a controlled and gradual manner while expanding the cranial volume. The purpose of this study was to evaluate outcomes following posterior cranial vault expansion using distraction osteogenesis at a single tertiary pediatric center.

METHODS

This retrospective review included all cases of posterior cranial vault distraction at a single institution from 2008 to 2022 performed by one surgeon. Morphometric outcomes such as Turricephaly Index (TI) and posterior cranial volume (PCV) were assessed from pre- and postoperative computerized tomography scans for patients who underwent posterior cranial vault distraction as a primary first-stage operation. Clinical outcomes and complications were collated.

RESULTS

A total of 41 patients (25 females, 16 males; mean age 11 months) with syndromic craniosynostosis (n = 32) and nonsyndromic craniosynostosis (n = 9) were included. The main indication for posterior cranial vault distraction in this cohort was turricephaly (63%). The mean distraction distance was 25.9 mm and the mean decrease in TI was 18%. The estimated increase in PCV from distraction in this cohort was 19.7%. In this cohort of patients, 13 patients (32%) experienced complications but there were no mortalities.

CONCLUSION

Posterior cranial vault distraction osteogenesis is an effective surgical procedure to increase intracranial volume and correct turricephaly in children with syndromic and nonsyndromic craniosynostosis. This procedure is considered a safe and effective first-stage cranial operation in children with syndromic craniosynostosis with increased intracranial pressure and or turricephaly.

Two-Center Review of Posterior Vault Expansion following a Staged or Expectant Treatment of Crouzon and Apert Craniosynostosis

BACKGROUND

The timing of posterior cranial expansion for the management of intracranial pressure can be "staged" by age and dysmorphology or "expectant" by pressure monitoring. The authors report shared outcome measures from one center performing posterior vault remodeling (PCVR) or distraction (PVDO) following a staged approach and another performing spring-assisted expansion (SAPVE) following an expectant protocol.

METHODS

Apert or Crouzon syndrome patients who underwent posterior expansion younger than 2 years were included. Perioperative outcomes and subsequent cranial operations were recorded up to last follow-up and intracranial volume changes measured and adjusted using growth curves.

RESULTS

Thirty-eight patients were included. Following the expectant protocol, Apert patients underwent SAPVE at a younger age (8 months) than Crouzon patients (16 months). The initial surgery time was shorter but total operative time, including device removal, was longer for PVDO (3 hours 52 minutes) and SAPVE (4 hours 34 minutes) than for PCVR (3 hours 24 minutes). Growth-adjusted volume increase was significant and comparable. Fourteen percent of PCVR, 33% of PVDO, and 11% of SAPVE cases had complications, but without long-term deficits. Following the staged approach, 5% underwent only PVDO, 85% had a staged posterior followed by anterior surgery, and 10% required a third expansion. Following the expectant approach, 42% of patients had only posterior expansion at last follow-up, 32% had a secondary cranial surgery, and 26% had a third cranial expansion.

CONCLUSION

Two approaches involving posterior vault expansion in young syndromic patients using three techniques resulted in comparable early volume expansion and complication profiles.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Perioperative Morbidity of Secondary Frontal Orbital Advancement After Initial Frontal Orbital Advancement

Frontal orbital advancement (FOA) is frequently performed for patients with syndromic and/or multisuture craniosynostosis. A small proportion of patients who undergo FOA have unfavorable growth and subsequently require a second FOA later in life; however, the perioperative risks associated with this second procedure are not well studied. We report results from a retrospective review of FOAs conducted from 2007 to 2022 at a single site with the same craniofacial surgeon. A total of 33 patients were included. Perioperative outcomes were compared between primary and secondary FOA procedures. The two groups were similar in regard to suture involvement and diagnosis, although the secondary FOA group was older at the time of their FOA (1.23 versus 7.07 y, P <0.001). There was no significant difference between groups in operating time, volume of blood transfusion by weight, or in the incidence of postoperative wound complications ( P >0.05). Primary FOA procedures had significantly higher weight-adjusted blood loss (28 versus 18 mL/kg, P =0.014), with a higher proportion of patients receiving a blood transfusion (95% versus 62%, P =0.025). There was no significant difference between groups in the incidence of intraoperative dural injury (50% versus 84%, P =0.067). Our findings suggest that secondary procedures appear to impose less of a surgical risk relative to primary FOA traditionally performed in infancy, likely because of the advanced age at the time of secondary FOA.

Posterior cranial vault distraction osteogenesis: A systematic review

Purpose

Posterior cranial vault distraction osteogenesis (PCVDO) has become the treatment of choice in specific indications within 12 years since its introduction in 2009. It is used to treat or prevent Intracranial hypertension secondary to craniosynostosis. However, there is still a lack of evidence describing this procedure's safety concerning the osteotomy line being close to the torcula. This systematic review aims to generate evidence regarding the safety of this new technique.

Materials and method

A systematic search of Pubmed and Embase database were done without any time limit until the last search date of July 31, 2021. Articles focused on posterior cranial vault distraction osteogenesis were shortlisted using defined inclusion criteria. In addition, complications, volume gain, and distraction protocols in patients with craniosynostosis were assessed.

Results

The review included 11 articles from 11 different centres. Of the Total 241 patients, 51 were non-syndromic patients, and 190 were syndromic patients. There were 242 procedures done on 241 patients. The proportion of patients with complications was 30%. Wound infection was the most commonly reported complication. PCVDO resulted in 20-25% volume gain and successfully prevented increased intracranial pressure (ICP).

Conclusion

The systematic review has significantly identified a 30.606% incidence of complications in PCVDO. No mortality was linked directly to the Posterior cranial vault distraction osteogenesis procedure (PCVDO). The authors identified the evolution of many unique vectors and osteotomy designs customized for patients and practices for safe surgery. The effects of PCVDO on the anterior cranial fossa remain a topic of interest and require observational studies for better understanding.

Comparing the Increased Intracranial Volume From Different Surgical Methods for Syndromic Craniosynostosis

PURPOSE

Fronto-orbital advancement (FOA) is the traditional surgical method used to increase intracranial volume, but posterior cranial vault distraction osteogenesis (PVDO) has been gaining popularity as an initial treatment option. This study aimed to compare the effects of FOA and PVDO on intracranial volume.

PATIENTS AND METHODS

Sixteen patients with multiple-suture synostosis and severe intracranial volume restriction were treated with FOA or PVDO at Children's Hospital of Fudan University between January 2016 and December 2019. Data on age at surgery, sex, preoperative intracranial volume, and postoperative intracranial volume were collected.

RESULTS

Seven patients underwent FOA and 9 underwent PVDO. All patients underwent surgery for the first time, and the surgeries were performed by the same physician. There was no statistically significant difference in age at surgery or in the intracranial volumes before and after surgery between the 2 groups (P>0.05). There was a statistically significant difference in the intracranial volume changes between the 2 groups before and after surgery (P=0.028).

CONCLUSIONS

Posterior cranial vault distraction osteogenesis provided statistically greater intracranial volume expansion than FOA.

Historical Perspectives on the Management of Craniosynostosis

The history of craniofacial surgery is one of many fundamental advances by monumental figures. Although craniosynostosis has been known to exist for multiple centuries, modern management has evolved over roughly the last century. An overview of early history, early scientific exploration, the advancement of surgical treatment of craniofacial deformities and the current state of craniosynostosis management is discussed. To fully appreciate the evolution of craniosynostosis surgery, one must understand the gradual advancements that have brought the specialty to this modern era.

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.

Early cranial vault distraction for a more balanced and enhanced expansion: a 3D craniometric analysis of anterior versus posterior distraction osteogenesis in patients with craniosynostosis

OBJECTIVE

Posterior distraction osteogenesis (DO) is widely accepted for the treatment of craniosynostosis. The aim of this study was to quantitatively compare the effect of DO on the cranial vault according to the age of the patient and direction of distraction.

METHODS

This was a retrospective study of patients with craniosynostosis who underwent DO in the anteroposterior direction. Postdistraction changes in intracranial volume (ICV), anteroposterior distance, biparietal distance, cranial height, and frontal bossing angle were measured using Mimics software on CT scans. Craniometric data were analyzed using a multivariate regression model.

RESULTS

Thirty-two patients (16 anterior and 16 posterior DOs) were included in the study. The mean ICV increase in the anterior and posterior DO group was 211 cm3 (range 142-281 cm3) and 214 cm3 (range 150-279 cm3), respectively. Patients who were aged 1 year or younger showed a greater percentage increase in ICV than patients older than 1 year. In the anterior DO group, a more balanced increase in both anterior and posterior anteroposterior distance was observed in patients aged 1 year or younger when compared to patients older than 1 year. In the posterior DO group, a bigger expansion and smoother contour in the posterior cranial fossa was observed in patients aged 1 year or younger.

CONCLUSIONS

Both anterior and posterior DO are effective surgical options for expanding the cranial vault in patients with craniosynostosis. Early distraction appeared to show greater morphological changes in the growing cranial vault than those predicted with the vector of distraction.

"Ten Years of Posterior Cranial Vault Expansion via Distraction Osteogenesis: An Update and Critical Evaluation"

PURPOSE

The goal of this study was to describe the 10-year evolution of our surgical technique and institutional perioperative outcomes using posterior vault distraction osteogenesis (PVDO) in patients with syndromic and multi-suture craniosynostosis.

METHODS

We performed a retrospective cohort study of patients who underwent PVDO for treatment of syndromic and multi-suture craniosynostosis at a single institution over a 10-year period. Demographic data, perioperative outcomes, distraction patterns, and complications were analyzed. Outcomes for patients in the first 5 years ("early cohort") were compared to those of the latter 5 years ("late cohort").

RESULTS

110 patients underwent a total of 118 PVDO procedures. Syndromic patients represented 83.6% of the cohort (n=92) and were significantly younger than non-syndromic patients at the time of first PVDO (median 14.1 [6.6, 40.1] vs 42.7 [15.2, 59.6] months, p=0.014). Mean distraction distance in the anterior-posterior direction was 30.8 mm (SD=7.4). Compared to the early cohort, PVDO in the late cohort had faster median operative times (144.0min [123.0, 189.0] vs 161.0min [138.0, 199.0], p=0.038), lower estimated blood loss as a percent of blood volume (28.5 [20.6, 45.3] vs 50.0 [31.1, 95.8], p<0.001), and lower blood replacement as percent of blood volume (39.5 [23.8, 59.1] vs 56.3 [37.8, 110.1], p=0.009).

CONCLUSIONS

Our 10-year experience with PVDO demonstrates continued overall safety and efficacy with improved perioperative outcomes over time. While it has become our first line of expansion in syndromic craniosynostosis, shortcomings such as need for device removal, infectious concerns, and potential for CSF leak merit attention by the craniofacial community.

Update in Management of Craniosynostosis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the craniofacial dysmorphology of craniosynostosis, and the variation of each type. 2. Identify the functional concerns and learn the rationale behind timing of operative intervention. 3. Approach each dysmorphology critically and identify the operative intervention needed to improve form and function 4. Understand and address the specific issues related to syndromic craniosynostosis and be able to delineate management plan.

SUMMARY

Craniosynostosis is a condition in which premature fusion of one or more cranial sutures lead to abnormal head shape and growth restriction of the brain. Nonsyndromic craniosynostosis occurs in isolation, and usually involves a single suture, whereas syndromic craniosynostosis may involve multiple sutures and is associated with extracraniofacial findings. Although surgical management can be similar, the treatment plan must take into consideration issues specific to the syndromes. This article aims to provide a concise overview of the authors' current understanding regarding the presentation, treatment principle, surgical option, and debates in craniosynostosis.

Transverse Distraction Osteogenesis for Posterior Narrowing of the Cranial Vault

SUMMARY

Although conventional posterior vault distraction osteogenesis is known to achieve the greatest improvement in intracranial volume, anteroposterior expansion of the cranial vault is not always ideal in certain head shapes. Transverse posterior vault distraction osteogenesis is an alternative reconstructive strategy in patients presenting with recalcitrant multisuture craniosynostosis resulting in scaphocephaly with posterior narrowing. The authors present a multimedia demonstration of placing the cranial hinge points at the superior anterior aspect of the bone segments in order to achieve increased intracranial volume and significant improvement in posterior head shape, while preserving normal anterior skull dimensions.

A Quantification of Scalp Thickness before and after Posterior Vault Distraction Osteogenesis

SUMMARY

Previous literature has documented craniometric changes of the bony calvaria, increases in intracranial volume, and resolution of Chiari malformations following posterior vault distraction osteogenesis. No studies have analyzed changes to the soft-tissue envelope after posterior vault distraction osteogenesis. In this study, the authors aimed to provide objective measurements of scalp thickness in patients undergoing posterior vault distraction osteogenesis, utilizing facial soft-tissue thickness as a proxy to control for growth. The authors hypothesized that the soft tissues of the scalp are not made thinner by the distraction process, either in the region of distraction or in neighboring areas. Subjects who underwent posterior vault distraction osteogenesis for a craniosynostosis diagnosis who had high-resolution predistraction and post-distractor removal computed tomographic scans within 100 days of each operation were included. The scans were analyzed on Materialise Mimics version 21 software (Materialise, Ghent, Belgium). Six key craniometric landmarks (glabella, pogonion, zygion, vertex, euryon, and opisthocranium) were identified on the three-dimensional bone masks in the Frankfort horizontal plane. The points were overlaid onto soft-tissue thickness masks and thicknesses were recorded. Percent change in postoperative facial soft-tissue thickness was used to control for growth of the craniofacial soft-tissue envelope during the study interval. The preoperative and postoperative posterior vault distraction osteogenesis cohorts did not differ significantly at the glabella, pogonion, opisthocranium, vertex, and zygion. The corrected median thickness at the euryon was significantly increased in the post-posterior vault distraction osteogenesis cohort [2.67 mm (IQR, 2.49 mm to 4.02 mm) versus 5.26 mm (IQR, 3.83 mm to 7.82 mm), p = 0.002]. This is the first study to quantify changes in soft-tissue thicknesses preoperatively and postoperatively in patients undergoing posterior vault distraction osteogenesis, demonstrating maintenance of scalp thickness. .

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis

OBJECTIVE

Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis.

METHODS

Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI.

RESULTS

A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation.

CONCLUSIONS

Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

Morbidity Associated With Anterior Versus Posterior Cranial Vault Expansion for Early Treatment of Syndromic Craniosynostosis: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to estimate and compare rates of unplanned reoperation and complications after undergoing either fronto-orbital advancement (anterior cranial vault expansion) or posterior cranial vault expansion as an early surgery in the management of syndromic craniosynostosis.

MATERIALS AND METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant articles were identified in 2 electronic databases (PubMed and EMBASE) from the time of electronic publication to November 2020. Quality assessment and risk of bias were appraised using the Grading of Recommendations Assessment, Development and Evaluation system. A meta-analysis was performed comparing rates of reoperation and complications between participants who underwent anterior or posterior cranial vault expansion as an early surgery.

RESULTS

Of 1,373 screened records, 7 met inclusion criteria. Six were included in the meta-analysis. The studies that met inclusion criteria reported on 103 patients treated with anterior techniques and 72 patients treated with a posterior approach. Anterior cranial vault expansion was associated with significantly higher rates of reoperation (Peto odds ratio = 2.83; 95% confidence interval = 1.19, 6.74, P = .02) and complications (Peto odds ratio = 2.61; 95% confidence interval = 1.12, 6.12, P = .03) than posterior cranial vault expansion.

CONCLUSIONS

Both anterior and posterior approaches are suitable options in the treatment of syndromic craniosynostosis depending on patient-specific factors. Anterior cranial vault expansion was associated with higher rates of unplanned reoperation and complications than posterior techniques in this analysis. Because of the paucity of literature which met inclusion criteria, this study was not able to assess critical outcome variables such as distance distracted/volumetric expansion, estimated blood loss, and cost. Larger studies evaluating both techniques under multiple institutions with long-term follow-up are indicated.

Intracranial Volume Measured and Correlated to Cephalic Index in Syndromic and Nonsyndromic Anterior Brachycephaly

BACKGROUND

Premature fusion of both coronal sutures (anterior brachycephaly) alters skull shape and potentially affects intracranial volume (ICV). Currently little is known about preoperative ICV in anterior brachycephaly. Aim is to measure preoperative ICV and compare this with normative data. Additionally, ICV will be correlated to most used clinical method of quantification: cephalic index (CI).

METHODS

Preoperative patients with anterior brachycephaly (age, ≤12 months) were included and categorized by syndrome (when present). Computed tomography scans were used for ICV measurement by manual segmentation (OsiriX (Fondation OsiriX, Geneva, Switzerland)). Intracranial volume of each subgroup was compared with Lichtenberg normative cranial volume growth curves for controls. Cephalic index was calculated and correlated to ICV using Pearson correlation coefficient.

RESULTS

Thirty-four patients with both syndromic and nonsyndromic anterior brachycephaly were included: 17 with Apert syndrome, 6 with Muenke syndrome, 5 with Saethre Chotzen syndrome, 3 with Crouzon, 1 with craniofrontonasal dysplasia, and 2 nonsyndromal. Mean age at preoperative computed tomography scan was 4 months (1-10 months). Mean ICV was 847.31 cm3 (473.91-1459.22 cm3). Nineteen of 34 patients had skull volumes between ±2 SD curves of Lichtenberg, none of the patients had an ICV smaller than -2 SD and 15 of 34 had an ICV larger than +2 SD. Mean ICV in Apert syndrome was 829.85 cm3 (473.91-1061.53 cm3), in Muenke syndrome 942.06 cm3 (768.02-1136.75 cm3), in Saethre Chotzen syndrome 779.72 cm3 (609.21-1002.95 cm3), in Crouzon syndrome 700.57 cm3 (652.31-784.32 cm3), in craniofrontonasal dysplasia 738.97 cm3, and in the nonsyndromal group 1154.64 cm3 (850.07-1459.22 cm3). Apert had a mean greater than +2SD above the mean, the other subgroups had a mean within normal ranges (±2 SD). Correlation between severity of brachycephaly and overall ICV was low (r = 0.42).

CONCLUSIONS

Mean preoperative ICV in both syndromic and nonsyndromic anterior brachycephaly was 847.31 cm3. Intracranial volume in anterior brachycephaly is in 55.9% between normal ranges (±2 SD). In 44.1% ICV was greater than +2 SD, especially in Apert syndrome (11/16 Apert patients). None of the included patients had a deviant small ICV of less than -2 SD. Additionally, low correlation between ICV and CI (r = 0.42) was found and therefore CI is not suitable for estimating ICV in anterior brachycephaly.

Posterior vault distraction osteogenesis: indications and expectations

Cranial vault remodeling (CVR) in patients with craniosynostosis serves to correct abnormal skull morphology and increase intracranial volume to prevent or treat pathologic increases in intracranial pressure (Taylor and Bartlett, Plast Reconstr Surg 140: 82e-93e, 2017). Distraction osteogenesis is a well-established technique for bony repositioning and growth stimulation in the facial and long bones, in which the gradual separation of bony segments at an osteotomy site results in generation of new bone and subsequent bone lengthening (Greene, 2018). While initially described in the orthopedic literature, the relevance and applicability of distraction osteogenesis to craniofacial surgery has been well-studied and is now well-established (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011). Posterior cranial vault distraction osteogenesis (PVDO) was introduced as a treatment option for cranial vault expansion in patients with craniosynostosis in 2009 by White et al., based upon the premise that posterior vault distraction could provide greater intracranial volume expansion than fronto-orbital advancement and remodeling (FOAR), but that acute posterior cranial vault expansions were limited by the soft tissue envelope of the infant scalp and prone to relapse related to the supine positioning typical of infants (White et al., Childs Nerv Syst 25: 231-236, 2009). Since this introduction, significant evidence has accrued regarding the safety of, and outcomes after, PVDO. PVDO is now known to provide larger increases in intracranial volume in comparison to anterior cranial vault remodeling procedures (Derderian et al., Plast Reconstr Surg 135:1665-1672, 2015) and to provide morphologic improvements in both the posterior and anterior cranial vaults (Goldstein et al., Plast Reconstr Surg 131:1367-1375, 2013). Perioperative major morbidity is comparable to conventional vault remodeling (Taylor et al., Plast Reconstr Surg 129:674e-680e, 2012) and the procedure has been safely applied to patients of various ages with syndromic and non-syndromic craniosynostosis (Zhang et al., J Craniofac Surg 29:566-571, 2018; Li et al., J Craniofac Surg 27:1165-1169, 2016). Many high-volume craniofacial centers now consider PVDO the preferred first operation in infants with syndromic craniosynostosis, and indications for this procedure continue to expand as evidence accrues regarding its utility and safety (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011; Swanson et al., Plast Reconstr Surg 137:829e-841e, 2016).

The Expanding Role of Posterior Vault Distraction Osteogenesis in Idiopathic Intracranial Hypertension and Slit Ventricle Syndrome

ABSTRACT

The purpose of this study was to compare perioperative safety and efficacy of posterior vault distraction osteogenesis (PVDO) in patients with primary nonsynostotic cephalo-cranial disproportion, namely slit ventricle syndrome and idiopathic intracranial hypertension (IIH), to a cohort of patients with craniosynostosis (CS). A retrospective review of patients undergoing PVDO from 2009 to 2019 at our institution was performed. Craniosynostosis patients were matched by sex and age at PVDO to the nonsynostotic cohort. Operative details, perioperative outcomes, and distraction patterns were analyzed with appropriate statistics. Nine patients met inclusion criteria for the non-CS cohort. Six patients (67%) underwent PVDO for slit ventricle and the remaining 3 patients (33%) underwent PVDO for IIH. The majority of CS patients were syndromic (n = 6, 67%) and had multisuture synostosis (n = 7, 78%). The non-CS cohort underwent PVDO at a median 56.1 months old [Q1 41.1, Q3 86.6] versus the CS cohort at 55.7 months [Q1 39.6, Q3 76.0] (P = 0.931). Total hospital length of stay was longer in the non-CS patients (median days 5 [Q1 4, Q3 6] versus 3 [Q1 3, Q3 4], P = 0.021). Non-CS patients with ventriculoperitoneal shunts had significantly less shunt operations for ICP concerns post-PVDO (median rate: 1.74/year [Q1 1.30, Q3 3.00] versus median: 0.18/year [Q1 0.0, Q3 0.7]; P = 0.046). In this pilot study using PVDO to treat slit ventricle syndrome and IIH, safety appears similar to PVDO in the synostotic setting. The cohort lacks adequate follow-up to assess long term efficacy, although short-midterm follow-up demonstrates promising results with less need for shunt revision and symptomatic relief. Future studies are warranted to identify the preferred surgical approach in these complex patients.

Surgical Result and Identification of FGFR2 Variants Using Whole-Exome Sequencing in a Chinese Family With Crouzon Syndrome

ABSTRACT

Crouzon syndrome is considered as one of the most common craniosynostosis syndromes with a prevalence of 1 in 65,000 individuals, and has a close relationship with variants in fibroblast growth factor receptor 2. Here the authors described a Crouzon syndrome case, which was asked for surgery treatment for the symptom of multisuture craniosynostosis. Mild midfacial retrusion, larger head circumference, proptosis, pseudo-prognathism, and dental malposition could also be found obviously. Then fronto-orbital advancement and cranial cavity expansion were performed to the child. After whole-exome sequencing (WES) and Sanger sequencing, gene variants in the exons 2 and 3 of FGFR2 were detected. And protein tyrosine 105 replaced by cysteine in the extracellular region of FGFR2 was also detected. After operation, she presented a satisfactory anterior plagiocephaly and scaphocephaly correction, and the result was satisfied by surgeons and her parents. Variants detected using WES have further research prospect.

Posterior Cranial Vault Distraction Osteogenesis Utilizing a Posterior-Superior Distraction Vector in the Treatment of Mercedes Benz Pattern Craniosynostosis

ABSTRACT

Bilateral lambdoid and sagittal synostosis, or Mercedes Benz Syndrome, is a rare complex craniosynostosis resulting in frontal bossing, a tapered posterior fossa, and an anteriorly displaced cranial vertex. Its ideal surgical correction must result in posterior expansion, skull elongation, and caudal repositioning of the vertex. We present a craniometric analysis of skull changes with posterior-superior distraction and introduce a novel craniometric measure: vertex position. In this study, a retrospective review was performed to analyze outcomes of posterior cranial vault distraction osteogenesis (PVDO) using a posterior-superior distraction vector from 2016 to 2019. Cranial vertex position was measured as a fraction of the occipitofrontal diameter from rostral to caudal (0-1.0). Four patients underwent PVDO at mean age 10.61 ± 3.16 months utilizing a posterior-superior distraction vector. Linear distraction distance averaged 30.30 ± 0.90 mm with a mean consolidation period of 3.98 ± 0.72 months. Mean corrected change in intra-cranial volume was 236.30 ± 3.71 mL, at an average rate of 7.81 ± 2.00 mL/mm of distraction. Increases in anterior cranial height (7.83 ± 2.51 mm), middle cranial height (8.43 ± 4.21 mm), posterior cranial height (13.15 ± 7.45 mm), and posterior cranial fossa height (21.99 ± 8.55 mm) were observed. Cranial vertex demonstrated a mean posterior movement of 0.18 ± 0.13. PVDO utilizing a posterior-superior distraction vector for management of nonsyndromic bilateral lambdoid and sagittal synostosis effectively increases intracranial volume and height and provides an esthetic outcome with posterior movement of the cranial vertex.

Endoscopic-Assisted Fronto-Orbital Distraction Osteogenesis: Initial Patient Report

BACKGROUND

The purpose of this manuscript is to introduce a novel endoscopic-assisted approach for creation of osteotomies and distractor hardware placement for unicoronal craniosynostosis.

METHODS

Only three small incisions are performed, one at the anterior fontanelle, pterional region, and upper lateral blepharoplasty location. Unicoronal strip craniectomy and osteotomies in temporal bone, nasofrontal junction, lateral orbital rim, sphenoid wing, orbital roof, and contralateral frontal bone are performed through these incisions with the assistance of a 30° 5-mm endoscope. One linear cranial distractor is inserted through the pterional incision and fixated across the unicoronal suturectomy.

RESULTS

Endoscopic-assisted fronto-orbital distraction osteogenesis has been performed on 3 patients with unicoronal craniosynostosis. Median age at surgery was 5.4 months (95%CI 5.0-6.1). Median operative duration was 98 minutes (95%CI 91-112), and estimated blood loss was 25 mL (95%CI 15-150). Median length of distraction achieved was 25.7 mm (95%CI 21.9-28.0), based on lateral skull x-rays obtained on the last day of activation. Distractors were removed 2.3 months postoperatively (95%CI 2.1-3.1), and operative duration of distractor removal was 20 minutes (95%CI 19-29). There was 1 complication, a transient cerebrospinal fluid leak thought to have been caused by a pinpoint injury to the dura at the nasofrontal junction, which was managed expectantly and resolved spontaneously by the fourth postoperative day.

CONCLUSIONS

Endoscopic-assisted fronto-orbital distraction osteogenesis is a promising treatment modality for children with unicoronal craniosynostosis combining the benefits of distraction osteogenesis with a minimally invasive approach. Additional experience and follow-up are needed to determine its utility, safety, and longevity.

Risk Factors for Occipital Step-Off Deformities in Posterior Vault Distraction Osteogenesis

PURPOSE

The goal of this study was to investigate patient specific factors and surgical techniques that affect occipital step-off deformity in children undergoing posterior vault distraction osteogenesis (PVDO).

METHODS

Patients who underwent PVDO were retrospectively reviewed and included if a high resolution three-dimensional computed tomography scan was available 1-year post-distractor removal. Two craniofacial surgeons were blinded to individual subjects and presented with 3 still images of three-dimensional bone reconstructions and asked to rate the degree of step off: none, mild, moderate, or severe. The data were analyzed with multinomial logistic regressions and other appropriate statistics.

RESULTS

Forty-one patients met inclusion criteria. All patients had multisuture or bicoronal craniosynostosis. Multinomial logistic regression identified age at PVDO (Cox and Snell = 0.487, P < 0.001) as a predisposing factor and one potentially protective factor, height of osteotomy (Cox and Snell = 0.394, P = 0.004) in univariate models. Post-hoc pairwise Mann-Whitney U test revealed there was decreased step-off rating when comparing osteotomy below torcula (median 0, [IQR 0, 3]) and above torcula (median 3 [IQR 1, 4]; P = 0.036) as well as a decreased step-off when below inion (median 0 [IQR 0, 1]; P = 0.001) was compared to above the torcula.

CONCLUSIONS

Older age at PVDO predict increased risk of developing an occipital step-off deformity after PVDO, while design of the occipital osteotomy below the inion is protective. Barrel staves with greenstick outfracture did not lower the risk of occipital step-off in this sample, the reasons for which are unclear.

Apert Syndrome Outcomes: Comparison of Posterior Vault Distraction Osteogenesis Versus Fronto Orbital Advancement

BACKGROUND

Presenting a wide clinical spectrum and large variety of clinical features, successful treatment of Apert syndrome necessitates performance of sequential multiple surgeries before a patient's facial skeleton growth is complete.The objective of this study is to compare forehead contour asymmetry and clinical outcomes between Apert patients who underwent either fronto-orbital advancement (FOA) or posterior vault distraction osteogenesis (PVDO).

METHODS

A retrospective study was performed on consecutive patients with Apert syndrome who underwent either FOA or PVDO between 2007 and 2019, and participated in at least 6 months of follow-up care. Forehead contour asymmetry and surgical outcomes for each of the included patients were verified through medical records, clinical photographs, and interviews with the parents of the patients. The need for additional craniofacial procedures based on the surgical outcomes of each patient was graded from I to IV utilizing the Whitaker outcome classification system.

RESULTS

Forehead contour asymmetry for all included patients was rated under the Whitaker grading scale as type II (n = 4) 44.4%, type III (n = 2) 22.2%, and type IV (n = 3) 33.3% for FOA, and type I (n = 5) 35.7%, type II (n = 7) 50%, and type III (n = 2) 14.3%, for PVDO (P < 0.05). The average transfused blood volume was 47.77 ± 9.42 mL/kg for patients who underwent FOA, and 22.75 ± 10.31 mL/kg for patients who underwent PVDO (P < 0.05).

CONCLUSIONS

Patients who underwent PVDO had lower forehead contour asymmetry as per the Whitaker outcome grading scale than patients who underwent FOA.

Posterior cranial vault distraction osteogenesis in the immunocompromised patient

PURPOSE

The treatment of patients with multisuture craniosynostosis is complex and patient-dependent. Cranial distraction osteogenesis is a relatively new procedure for treatment of these patients, with its use increasing in many centers. With this increased use comes an expanding range of indications. Surgical management of multisuture craniosynostosis in therapeutically immunosuppressed patients following a solid organ transplant presents unique challenges. We describe our experience with posterior cranial vault distraction in two patients with multisuture craniosynostosis that had previously undergone organ transplantation.

METHODS

Two solid-organ transplant recipient patients with multisuture craniosynostosis were identified. A detailed examination of their medical/transplant history and perioperative details were recorded.

RESULTS

The first patient was a 3-year-old girl who received a kidney transplantation in infancy and subsequently presented with a symptomatic Chiari malformation and papilledema. Imaging revealed pansynostosis. She underwent posterior cranial vault distraction extending into a Chiari decompression. Her postoperative course was complicated by distractor site infection at the beginning of consolidation, necessitating early removal of distractors. The second patient was a 2-year-old boy who received a heart transplantation at the age of 3 months and subsequently presented with head shape concerns. Imaging revealed bicoronal and sagittal craniosynostosis. He underwent a posterior cranial vault distraction without complication. Following removal of the distractors, he developed an infection at one of the distractor sites with associated fever and leukocytosis, necessitating washout and drain placement. Both patients achieved successful cranial vault expansion with distraction osteogenesis and at a 2-year follow-up do not have evidence of elevated intracranial pressure.

CONCLUSIONS

Immunosuppressive therapy has the potential to inhibit wound healing and place patients at risk for wound infection. Although we have demonstrated successful cranial vault expansion with distraction in two immunosuppressed children, extra care must be taken with these patients when placing semi-buried hardware. Specifically, prompt identification and proactive management of potential infectious complications is critical to applying this technique safely in these patients.

Craniometric and Volumetric Analysis of Posterior Vault Distraction Osteogenesis: 10 Year Update

PURPOSE

The purpose of this study is to quantitatively establish the volumetric changes observed with posterior vault distraction osteogenesis in the anterior, middle, and posterior thirds of the cranial vault; characterize change in cranial length, width, and height, correlating these changes to demographic variables that may help identify why younger kids gain more volume; and describe the short-term position of the transport segment.

METHODS

Multisuture craniosynostosis patients who underwent posterior vault distraction osteogenesis were retrospectively reviewed. Pediatric, dose-reduced, thin cut helically acquired head computed tomography scans were analyzed on Materialise Mimics v22 (Materialise, Ghent, Belgium). Pre and post-PVDO and "old" and "young" cohort were compared.

RESULTS

Twenty-one patients met inclusion criteria. The change in cranial length was significantly less at a median of 14.9 mm [Interquartile range (IQR) 11.8, 31.6] compared to the X-ray measured AP distraction distance (30 mm [IQR 24, 33]; P < 0.001) and significantly less than the theoretically calculated distance (23 mm [IQR 19, 31]; P = 0.012). Median anterior cranial height was shorter post PVDO (82.9 mm, [IQR 64.8, 92.6] versus 78.7 mm [IQR 57.0, 88.7]; P = 0.030). The younger cohort saw a greater increase in total intracranial volume (median 335.1 mL [IQR 163.2, 452.3, median 37.1%] versus 144.6 mL [IQR 119.0, 184.8, median 12.0%]; P = 0.011).

CONCLUSIONS

This is the first study to quantify volumetric changes to the anterior, middle, and posterior cranial vaults and demonstrates benefits of preforming PVDO at a younger age to help control turricephaly and produce greater percentage volumetric increases.

A Review on Variability in Treatment Protocols With Posterior Cranial Vault Distraction

BACKGROUND

Prior studies have confirmed the ability of posterior cranial vault distraction osteogenesis (PVDO) to expand the intracranial volume in patients with craniosynostosis. To date, there is scant literature on the optimal distraction protocol for PVDO. The authors sought to review the literature and define a common protocol for posterior cranial vault distraction.

METHODS

The authors performed a systematic review for published PVDO protocols. The data collected from these studies included age at the time of PVDO, number of distraction devices placed, time for latency, rate and rhythm of distraction, distraction length, time for consolidation, and surgical outcomes.

RESULTS

A total of 286 patients were identified within 24 studies from 2011 to 2019. The mean age of patients identified was 25.34 months. After application of distractors, latency period ranged between 1 and 7 days, with most patients undergoing 5 to 7 days of latency. Once distraction was begun, the majority of patients (77.4%) underwent 1 mm of distraction daily. Total lengths of distraction ranged between 13 and 35 mm, with the largest cohort of patients undergoing 26 to 30 mm of total distraction. A total of 60 complications were reported for a total of 212 patients, yielding an overall complication rate of 28.3%.

CONCLUSIONS

Although there is variability in reported PVDO protocols, the majority are similar to distraction osteogenesis protocols described for long bone sites. Increased patient age correlates with selection of a greater latency period and total distraction length, while frequency of complications is also increased.

Serial Posterior Cranial Vault Distraction for the Treatment of Complex Craniosynostosis

ABSTRACT

Posterior cranial vault distraction is an important modality in the management of craniosynostosis. This surgical technique increases intracranial volume and improves cranial aesthetics. A single procedure is often inadequate in patients with complex multisuture craniosynostosis, as some will go on to develop intracranial hypertension despite the operation. Considering the negative effects of intracranial hypertension, some patients may warrant 2 planned distractions to prevent this scenario from ever occurring. Three patients with complex multiple-suture synostosis and severe intracranial volume restriction (occipital frontal head circumferences [OFCs] <1st percentile) were treated with 2 planned serial posterior cranial vault distractions at the institution between 2013 and 2018. Demographics, intraoperative data, and postoperative distraction data were collected. The OFC was recorded pre- and postdistraction, at 3- and 6-month follow-up appointments. Patients had a corrected average age of 18 weeks at the time of their initial procedure. There was an average of 38 weeks between the end of consolidation and the time for their 2nd distraction procedure. There was an average age of 79 weeks at the time of the 2nd procedure. All patients had a substantial increase in OFC and improvement of the posterior calvarium shape. The average increase in OFC was 5.2 cm after first distraction and 4.3 cm after 2nd distraction. No postoperative complications were encountered. Planned serial posterior cranial vault distraction is a safe and effective strategy for increasing intracranial volume, improving aesthetic appearance, and preventing the consequences of intracranial hypertension in patients with multisuture craniosynostosis and severe intracranial volume restriction.

Syndrome-related outcomes following posterior vault distraction osteogenesis

PURPOSE

The most commonly occurring syndromic craniosynostoses are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, and Saethre-Chotzen syndrome. There is insufficient data regarding postoperative syndrome-related outcomes following the posterior vault distraction osteogenesis (PVDO) procedure, as well as data addressing whether or not additional procedures will be subsequently necessary to comprehensively treat children who undergo PVDO. Thus, the objective of this study is to describe and compare syndrome-related potential complications and outcomes associated with the PVDO procedure.

METHODS

An observational retrospective study was performed on consecutive patients (n=24) with Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, or Saethre-Chotzen syndrome, respectively, who underwent PVDO between 2012 and 2019. Demographic data (patient gender and age when the PVDO procedure was performed), diagnosis, surgery-related data, and outcome data (perioperative and midterm complications and need for additional surgery) were verified.

RESULTS

Total relative blood transfusion volumes per kilogram for the patients were as follows: 22.75 ± 9.30 ml for Apert syndrome, 10.73 ± 2.28 ml for Crouzon syndrome (Apert versus Crouzon, p<0.05), 18.53 ± 8.08 ml for Pfeiffer syndrome, and 19.74 ± 9.12 ml for Saethre-Chotzen syndrome. None of the patients required a secondary procedure to alleviate intracranial pressure except for a Saethre-Chotzen patient.

CONCLUSION

PVDO is an effective technique to address elevated intracranial pressure in SC patients that alleviates the need for secondary procedures at midterm follow-up. Apert syndrome patients presented relatively higher total blood transfusion rates than Crouzon syndrome patients who were operated on at a later age and weighed more.

Craniosynostosis: Posterior Cranial Vault Remodeling

Posterior cranial vault distraction osteogenesis is a powerful, reliable, low-morbidity method to achieve intracranial expansion. It is particularly useful in treating turribrachycephaly seen in syndromic craniosynostosis, allowing for gradual expansion of the bone while stretching the soft tissues over several weeks allowing greater volumetric expansion than conventional techniques. Posterior cranial vault distraction osteogenesis constitutes a more gradual remodeling modality, with infrequent complications. As a first step in intracranial expansion, it preserves the frontal cranium for future frontofacial procedures. A drawback is the need for a second surgery to remove the device, and this must be taken into account during counseling.

Distraction Osteogenesis in Craniofacial Surgery: Past, Present, and Future

ABSTRACT

Distraction osteogenesis (DO) is considered one of the treatments of choice for the surgical correction of malformations of the craniofacial skeleton. This is due to its ability to generate bone at the distraction site along with the accompanying soft tissue changes, the possibility to combine DO with traditional orthognathic procedures and the successful reported long-term outcomes following its application to various craniofacial deformities. The aim of this review is to present an overview of the literature on the evolution of DO applications in craniofacial surgery through the last 35 years.

Postnatal Sagittal Craniosynostosis: A Novel Presentation and Considerations in Diagnosis and Management

ABSTRACT

Sagittal craniosynostosis results in scaphocephaly from abnormal fusion of the sagittal suture. Traditionally, craniosynostosis presents at birth and is diagnosed within the first year of life. We report a patient with development of sagittal craniosynostosis after birth, which we term postnatal sagittal craniosynostosis (PSC). This is a rare occurrence in which management considerations are critical but are not well discussed. A 3-year old boy presented with concerns of a metopic ridge. Work-up revealed metopic ridging and an open sagittal suture. The patient later developed signs of increased intracranial pressure (ICP) and repeat CT scan 14 months later identified a newly fused sagittal suture. The patient underwent open posterior cranial vault expansion, resulting in resolution of symptoms. PSC is a rare condition and should be considered in otherwise unexplained increases in ICP among pediatric patients. Open posterior cranial vault expansion represents a safe and effective method to treat this condition.

Posterior calvarial distraction for complex craniosynostosis and cerebellar tonsillar herniation

OBJECTIVE

Children with syndromic, multisuture, and lambdoid craniosynostosis undergoing calvarial surgery often have Chiari malformation type I (CM-I) (or cerebellar tonsillar herniation). The optimal management of this patient group, including the surgical techniques and timing of surgery, remains uncertain. Posterior calvarial distraction (PCD) is an effective method to increase the supratentorial cranial volume and improve raised intracranial pressure in children with complex craniosynostosis. This study investigated the efficacy of PCD in posterior fossa (PF) volume expansion and treatment of CM-I and associated syringomyelia (syrinx) in this group of children.

METHODS

This retrospective study included patients who were surgically treated between 2006 and 2015. Over 10 years, 16 patients with multisuture synostosis, lambdoid synostosis, or craniosynostosis associated with a confirmed genetic syndrome, and a concurrent CM-I, were included. The mean age at the time of surgery was 5.1 years (range 8 months-18 years). Fourteen patients had pansynostosis and 2 had lambdoid synostosis. Eight had a confirmed syndromic diagnosis (Crouzon in 8, Apert in 4, Pfeiffer in 1, and Saethre-Chotzen in 1). Ten patients had raised intracranial pressure; 4 had syringomyelia.

RESULTS

The average clinical follow-up was 50 months (range 9-116 months). Clinically, 9 patients improved, 7 remained stable, and none deteriorated. The average distraction distance was 23 mm (range 16-28 mm). The PF anterior-posterior (AP) distance/width ratio increased from 0.73 to 0.80 mm (p = 0.0004). Although an osteotomy extending inferior to the torcula (compared with superior) was associated with a larger absolute PF AP distance increase (13 vs 6 mm, p = 0.028), such a difference was not demonstrable when the PF AP distance/width ratio was calculated. Overall, the mean tonsillar herniation improved from 9.3 to 6.0 mm (p = 0.011). Syrinx dimensions also improved in the AP (from 7.9 to 3.1 mm) and superior-inferior (from 203 to 136 mm) dimensions. No patients required further foramen magnum decompression for CM. Of the 16 patients, 2 had subsequent frontoorbital advancement and remodeling, of which 1 was for volume expansion and 1 was for cosmetic purposes. Two patients required CSF shunt insertion after PCD.

CONCLUSIONS

Following PCD, PF volume increased as well as supratentorial volume. This morphometric change was observed in osteotomies both inferior and superior to the torcula. The PF volume increase resulted in improvement of cerebellar tonsillar herniation and syrinx. PCD is an efficacious first-line, single-stage treatment for concurrent pansynostosis and lambdoid craniosynostosis, CM-I, and syrinx.

Spring-Assisted Surgery for Treatment of Sagittal Craniosynostosis

ABSTRACT

Craniosynostosis (CSS), the premature fusion of calvarial sutures, most commonly involves the sagittal suture. Cranial vault remodeling (CVR) is a traditional method of CSS correction. Minimally invasive methods are becoming widely accepted, including spring-assisted surgery (SAS). The equipment required for SAS is minimal therefore adaptable to resource challenged health systems. This paper outlines the experience of SAS in Moldova.A retrospective study was performed for patients treated with SAS for sagittal CSS from 2011 to 2018 in Moldova. Perioperative data were recorded including age, length of surgery, blood loss, volume transfused and length of stay. Four patients had pre- and post-operative computed tomography (CT) scans which were used to calculate changes in cephalic index, normative cephalic index, and intracranial volume.Thirteen patients underwent SAS. Diagnoses were made clinically and confirmed with CT. Mean age at surgery was 4.0 months, and length of surgery 62.7 minutes. All but one patient received a blood transfusion, as is standard of practice in Moldova. The mean length of post-operative recovery in ICU was 30.9 hours. No complications required surgical revision. Springs were removed after 4 to 5 months. All patients had a subjective improvement in scaphocephaly. Based on the available CT scans, an increase in cephalic index (7.3%), normative cephalic index (11.8%), and intracranial volume (38.1%) was observed. One patient underwent SAS at 11 months and required cranioplasty for asymmetry at the time of spring removal.SAS is a safe and cost-effective method of CSS correction that can be utilized in countries with limited health system resources.

Ventricular shunt complications in patients undergoing posterior vault distraction osteogenesis

PURPOSE

The primary objective of this study is to investigate post-operative morbidity and shunt revision rates of patients with shunt-dependent hydrocephalus (SDH) undergoing posterior vault distraction osteogenesis (PVDO) compared to patients undergoing conventional posterior vault reconstruction (PVR).

METHODS

A retrospective case-controlled cohort analysis of all patients with SDH undergoing PVDO and PVR for syndromic or complex craniosynostosis was performed. Demographic information, perioperative variables, distraction protocols, and shunt-related complications-infection, surgical revision of shunt, increased length of stay (LOS), and readmission within 90 days of surgery-were compared using the appropriate statistical tests.

RESULTS

Fourteen patients with ventricular shunts who underwent PVDO and eight patients with shunts who underwent PVR were identified. Shunt-related complication rates were significantly higher with PVDO (n = 5) compared to PVR (n = 0), p = 0.0093. Among the five patients who suffered complications, the most common were shunt infection (n = 4), shunt malfunction (n = 4), and wound infections (n = 3). All patients with complications required additional operations for shunt revision and/or replacement; four patients required multiple takebacks for such procedures, with an average of three additional procedures per patient.

CONCLUSIONS

In complex or syndromic craniosynostosis patients who have previously undergone ventricular shunting, PVDO is associated with higher shunt-related complications and need for additional procedures when compared to traditional PVR. While the benefits of PVDO in the treatment of syndromic craniosynostosis are well documented, the risks of PVDO in the face of a VP shunt must be considered. Further investigation into patient-specific risk factors and risk reduction strategies is warranted.

A Craniometric Analysis of the Posterior Cranial Base After Posterior Vault Distraction

BACKGROUND

Posterior vault distraction osteogenesis (PVDO) has been demonstrated to effectively increase intracranial volume, treat increased intracranial pressure, and improve head shape in syndromic patients. The purpose of this study is to compare changes along the posterior cranial base before and after distraction.

METHODS

A retrospective review was completed of subjects who underwent PVDO with computed tomography scans at 2 time-points: within 3 months preoperatively and 1 to 6 months postoperatively. Using Mimics software, craniometric landmarks were identified and surface area of the foramen magnum was calculated. A comparison of pre- to postoperative measurements was completed using Wilcoxon matched-paired signed rank tests and linear regression.

RESULTS

A total of 65 PVDO subjects were identified, 12 subjects met inclusion criteria. Mean operative age was 3.0 ± 4.0 years. The cranial vault was distracted on average 25.0 ± 6.0 mm, with those < 12 months of age distracted 29.5 ± 4.9 mm and >12 months of age distracted 22.0 ± 4.9 mm (P = 0.0543). There was a significant increase in pre- to postoperative foramen magnum surface area (52.1 ± 63.2 mm, P = 0.002), length (0.9 ± 1.4 mm, P = 0.050), and width (0.6 ± 1.0 mm, P = 0.050). Similarly, linear distances between nasion and posterior cranial base landmarks such as foramen magnum (3.4 ± 4.2 mm, P = 0.010), and occipital protuberance (9.1 ± 9.6 mm, P = 0.003) were increased. Subjects under 12 months had a greater percentage increases in posterior vault length than those over 12 months.

CONCLUSION

Posterior vault distraction osteogenesis is associated with an increase in size of the foramen magnum, and lengthening of the posterior cranial base, both of which may be beneficial in patients with turribrachycephaly.

Onset and Resolution of Chiari Malformations and Hydrocephalus in Syndromic Craniosynostosis following Posterior Vault Distraction

BACKGROUND

Patients with syndromic craniosynostosis have an increased incidence of progressive hydrocephalus and Chiari malformations, with few data on the relative benefit of various surgical interventions. The authors compare the incidence and resolution of Chiari malformations and hydrocephalus between patients undergoing posterior vault distraction osteogenesis (PVDO) and patients undergoing conventional cranial vault remodeling.

METHODS

Patients with syndromic craniosynostosis who underwent cranial vault surgery from 2004 to 2016 at a single academic hospital, with adequate radiographic assessments, were reviewed. Demographics, interventions, the presence of a Chiari malformation on radiographic studies and hydrocephalus requiring shunt placement were recorded. Mann-Whitney U and Fisher's exact tests were used as appropriate.

RESULTS

Forty-nine patients underwent PVDO, and 23 patients underwent cranial vault remodeling during the study period. Median age at surgery (p = 0.880), sex (p = 0.123), and types of syndrome (p = 0.583) were well matched. Patients who underwent PVDO had a decreased incidence of developing Chiari malformations postoperatively compared with the cranial vault remodeling cohort (2.0 percent versus 17.4 percent; p = 0.033). Not surprisingly, no significant difference was found between the groups with regard to the incidence of postoperative hydrocephalus requiring shunt placement (PVDO, 4.1 percent; cranial vault remodeling, 4.3 percent; p = 0.999).

CONCLUSIONS

As expected, PVDO did not significantly affect intracranial hydrodynamics to the extent that hydrocephalus shunting rates were different for patients with syndromic craniosynostosis. However, PVDO was associated with a reduced risk of developing a Chiari malformation; however, prospective evaluation is needed to determine causality.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Evaluation of Endoscopic Strip Craniectomy and Orthotic Therapy for Bilateral Coronal Craniosynostosis

BACKGROUND

Bilateral coronal craniosynostosis is the premature fusion of both coronal sutures. Traditionally, this condition is treated by frontal-orbital advancement (FOA). Endoscopic strip craniectomy with cranial orthotic therapy, which has gained popularity in treating single suture craniosynostosis, has recently been adapted for the treatment of bicoronal synostosis. There have been few studies documenting the outcomes of this treatment. The objective of this study is to compare the morphological outcomes of endoscopic strip craniectomy and FOA in patients with bicoronal synostosis.

METHODS

A retrospective case series was done on 24 patients with bilateral coronal synostosis treated with endoscopic strip craniectomy or FOA at 2 institutions. Patients with preoperative and 1-year postoperative computed tomography scans were included. Multiple measures of cranial shape and size were assessed: cephalic index, turricephaly index, basofrontal angle, circumference Z-score, and cranial vault volume Z-score.

RESULTS

The 2 groups were similar statistically in terms of morphology at preoperative scan. There were no statistical differences between the FOA group and endoscopic group at postoperative scan in any of the morphologic outcomes measured. Cranial vault volume Z-scores increased postoperatively in both the endoscopic (P < 0.001) and FOA (P = 0.034) groups.

CONCLUSIONS

One year after repair there were no significant morphological difference between patients with bicoronal synostosis treated with the endoscopic approach and those treated by FOA.