Posterior Cranial Vault Distraction in the Treatment of Shunt-Induced Craniosynostosis

Craniofacial Distraction Osteogenesis

Distraction osteogenesis (DO) of the craniofacial skeleton has become an effective technique for the treatment of both nonsyndromic and syndromic conditions. The advent of craniofacial DO has allowed for earlier intervention in pediatric patients with less complication risk and morbidity compared to traditional techniques. In this review, we will discuss current application and technique for craniofacial DO by anatomical region and explore future applications in craniofacial surgery.

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.

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.

Craniosynostosis Develops in Half of Infants Treated for Hydrocephalus with a Ventriculoperitoneal Shunt

BACKGROUND

Craniosynostosis following placement of a ventriculoperitoneal shunt for hydrocephalus has been sporadically described. The purpose of this investigation was to determine the general risk of developing craniosynostosis in this patient population.

METHODS

The authors retrospectively reviewed records and radiographs of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus from 2006 to 2012. Recorded variables included date of shunt placement, demographics, comorbidities, cause of hydrocephalus, shunt type, and number of shunt revisions. Axial computed tomographic images obtained before and immediately after shunt placement and 2 to 4 years after shunt placement were evaluated by a panel of clinicians for evidence of craniosynostosis. Patients with preshunt craniosynostosis, craniosynostosis syndromes, or poor-quality computed tomographic images were excluded. Data were analyzed using STATA Version 15.1 statistical software.

RESULTS

One hundred twenty-five patients (69 male and 56 female patients) were included. Average age at shunt placement was 2.3 ± 2.58 months. Sixty-one patients (48.8 percent) developed craniosynostosis at a median of 26 months after shunt placement. Of these, 28 patients fused one suture; the majority involved the sagittal suture (n = 25). Thirty-three patients fused multiple sutures; the most common were the coronal (n = 32) and the sagittal (n = 30) sutures. Multivariable logistic regression identified older age at shunt placement and more shunt revisions as independent predictors of craniosynostosis. Shunt valve type was not significant.

CONCLUSIONS

Craniosynostosis developed in nearly half of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus. The sagittal suture was most commonly involved. The effect of suture fusion on subsequent cranial growth, shunt failure, or the development of intracranial pressure is unclear.

CLINICAL QUESITON/LEVEL OF EVIDENCE

Risk, III.

Management of Pre-existing Ventriculoperitoneal Shunt in Posterior Vault Distraction for Lambdoid Craniosynostosis: A Case Report and Technical Note

Posterior vault distraction osteogenesis (DO) is an emerging treatment option for craniosynostosis. Operative nuances detailing surgical management are being described with increasing use and experience. In this article, we discuss the surgical management of an 8-month-old male with a ventriculoperitoneal shunt (VPS) diagnosed with bilateral lambdoid craniosynostosis and Chiari I malformation. The patient underwent successful bilateral posterior fossa DO without surgical re-implantation of the shunt. Pre- and post-operative imaging confirmed no migration of the VPS. Intracranial volume increased by 20.1% and posterior fossa volume increased by 39.9%. Our experience illustrates that posterior vault DO can be done safely in the setting of a parieto-occipital VPS, in a single operative setting, without the need of additional procedures.

Aesthetic Cranial Vault Expansion in a Child With Slit Ventricle Syndrome and Eumorphic Face

Ventricular shunting procedures represent the classical surgical treatment for hydrocephalus. Slit ventricle syndrome (SVS) with craniocerebral disproportion (CCD) and secondary craniosynostosis (SCS) is a well-known but uncommon complication following cerebrospinal fluid (CSF) shunting in children. Its general management includes shunt upgrade or revision, placement of anti-siphon devices, lumbo-peritoneal shunting, and endoscopic third ventriculostomy. Cranial expansion is generally considered a major procedure and is indicated when less invasive treatments fail. In these cases, SVS and associated SCS have been usually managed through anterior cranial vault expansion. This procedure aims to decrease the risk of further shunt revisions and to improve neurologic symptoms, but it takes the disadvantage of considerable iatrogenic alterations of the facial proportions. The authors report a case of a 6-year old boy with SVS and SCS, who maintained eumorphic face and was treated by an innovative post-coronal vault expansion ensuring a wide volume increase while avoiding any change of facial conformation.

The Incidence of Chiari Malformations in Patients with Isolated Sagittal Synostosis

Background:

We report the incidence of Chiari malformation I (CMI) in a cohort of 377 patients with isolated sagittal synostosis (ISS), which is to the best of our knowledge the largest such series reported to date.

Methods:

A retrospective review of patients seen at a single institution from 2007 to 2017 was completed. ISS, Chiari malformations (CMI and CMII) and hydrocephalus were diagnosed by a senior neuroradiologist (G.Z.). Patients who met the inclusion criteria were divided into early (group A) and late (group B) presenting groups, as well as operated (group I) and unoperated (group II) groups. The patients were further subdivided into group AI (early operated), group AII (early unoperated), group BI (late operated), and group BII (late unoperated). Once identified, patient notes were examined for the following data sets: date of birth, age of presentation, age at last follow-up, other systemic conditions as well as molecular testing results. Surgical interventions, ophthalmological, and other relevant data were recorded. Statistical analysis was run in the form of a chi-square test to identify a significant difference between each subgroup. A literature review of the incidence of Chiari malformations in patients with ISS was conducted.

Results:

Three hundred seventy-seven patients constitute the study’s total cohort (272 were males and 105 females). This cohort was divided into patients who underwent surgical repair of ISS (group 1: n = 200), and patients who did not (group 2: n = 177). The entire cohort was also divided into early (group A: n = 161) and late (group B: n = 216) presenting craniosynostosis. In the total cohort, 22/377 (5.8%) patients with CMI were identified. CMI was found in 14/200 (7.0%) patients in group I, and 8/177 (4.5%) patients in group II. CMI was found in 2/161 (1%) patients in group A, and 20/216 (9.2%) patients in group B. The incidence of CMI in group AI (early operated) was 2/151 (1.3%), in group AII (early unoperated) was 0/10, in group BI (late operated) was 11/49 (21%), and in group BII (late unoperated) was 9/167 (5.4%). Chi-square analysis revealed a significant difference between the incidence of CMI in the early-presenting (group A) and late-presenting (group B) groups (P = 0.001) and between the late-presenting operated (BI) and late-presenting unoperated (BII) groups (P = 0.001). The incidence of hydrocephalus was 1.6% (6/377) in the total cohort. However, all patients diagnosed with hydrocephalus came from group II (no surgical ISS correction). The incidence of hydrocephalus in group II was 3.3% (6/177). The incidence of hydrocephalus in group BII (late unoperated ISS) was 3.0% (5/167). The incidence of hydrocephalus in group AII (early unoperated ISS) was 9.0% (1/11).

Conclusions:

We noted the highest incidence of CMI—21%—in group BI (late-presenting operated). We noted hydrocephalus in group II (nonoperated), with the highest incidence of hydrocephalus found in the group BII (late-presenting unoperated) subgroup. We therefore recommend patients with ISS receive funduscopic examination to screen for raised intracranial pressure (ICP) associated with CMI and hydrocephalus, especially patients with late-presenting ISS.

Conservative and operative management of iatrogenic craniocerebral disproportion-a case-based review

INTRODUCTION

Craniocerebral disproportion (CCD) can occur as a sequela after shunting in early infancy. It can be understood as a disorder closely related to slit ventricle syndrome and chronic overdrainage syndrome. Here, we present two exemplary cases and summarize the pathophysiological, diagnostic, and therapeutic approaches to CCD.

CLINICAL PRESENTATION

Two premature babies underwent shunting for posthemorrhagic hydrocephalus and presented in later childhood with recurrent episodes of symptomatic raised intracranial pressure (ICP) at 2 and 8 years of age, respectively.

DIAGNOSIS AND MANAGEMENT

Both patients had unchanged ventricular size on cranial imaging and fulfilled the clinical diagnostic criteria of CCD. After confirming shunt patency, ICP monitoring was performed to diagnose intermittent intracranial hypertension. Different treatment pathways were pursued: While readjustment of a programmable shunt valve was sufficient to alleviate the raised ICP in the first case, a cranial expansion surgery was necessary in the second case.

OUTCOME AND CONCLUSIONS

Both children were treated successfully after thorough assessment and careful choice of treatment approaches. This review provides detailed insight into CCD and highlights the importance of individual and critical decision-making in these complex patients.

Surgical management of craniosynostosis in the setting of a ventricular shunt: a case series and treatment algorithm

PURPOSE

Cerebrospinal fluid diversion via ventricular shunt is a common treatment for hydrocephalus. Change in cranial morphology associated with a sutural fusion has been termed shunt-related or induced craniosynostosis (SRC) or craniocerebral disproportion (CCD). We present a series of patients with SRC who underwent cranial vault remodeling (CVR) and our treatment algorithm.

METHODS

Thirteen patients were retrospectively reviewed who had SRC and CVR; 92% of patients had a ventriculoperitoneal (VP) shunt placed for largely intraventricular hemorrhage of prematurity (69% of patients) at a mean age of 2.2 months. The shunt revision rate was 38.4%, and 54% of patients had a programmable shunt placed initially.

RESULTS

The mean age at time of CVR was 3.6 years old. The most commonly affected sutures (CT confirmed) were the sagittal and coronal sutures, with three patients exhibiting pancraniosynostosis. The mean time from placement of the shunt to CT evidence of sutural fusion was 2.0 years. Abnormal head shape was noted in all 13 patients; 11 of these also had either chronic headaches, papilledema, seizures, or behavioral changes in the setting of functional shunt. Mean follow-up after the initial CVR was 3.3 years. No shunt infections were attributed to the CVR. The families of all patients were contacted and reported improvement in head shape with 60% of families reporting improvement in behavior, 75% reported improvement in headaches, and 40% reported decrease in seizure frequency or intensity. Shunt setting or type was not routinely changed after CVR.

CONCLUSIONS

Our threshold for CVR in SRC is met when shunt malfunction has been ruled out and there are (1) radiographic evidence of craniosynostosis, (2) signs of increased ICP clinically or radiographically, and (3) cranial dysmorphism, i.e., dolichocephaly. The majority of cases of SRC result in improved cranial morphology in addition to some abatement of the symptoms of increased intracranial pressure. Early involvement of an experienced craniofacial/neurosurgical team could allow for early diagnosis and intervention which may prevent progression to more severe deformities. SRC is a complex entity, with multiple etiologies, and a future study is needed.

Chronic Debilitating Headache in Adults Caused by Craniocerebral Disproportion: Treatment by Cranial Vault Expansion

Craniocerebral disproportion is rarely considered as a cause for chronic, debilitating headache in adults. Children reported with this disorder typically suffer from headaches and lethargy for many years and have multisutural synostosis. The terms craniocerebral disproportion, craniostenosis, and slit-ventricle syndrome are used inconsistently as diagnostic designations. Three adults with craniocerebral disproportion who had been treated in infancy for two different pathologies are reported. All benefited greatly from cranial vault expansion.

Wire fixation of internal distractor for cranial vault remodeling

BACKGROUND

Posterior cranial vault distraction osteogenesis is currently used to enlarge the cranial volume and control the intracranial pressure. This procedure carries the risk of hardware dislocation, and especially in infants, as their skull being thin, the screws may damage the underlying dura.

TECHNICAL NOTE

In this paper, the authors describe a simple method to fixate the internal distractor to the skull vault in case of thin calvaria using metallic wires.

DISCUSSION

This method allows a strong and tight application of the distractor to the osteotomy margins and reduces the risks of loosening of the device and the risk of dural tears. It is particularly useful in young children or in case of diffuse digitate impressions with areas of reduced thickness of the skull bone.