Posterior calvarial distraction in craniosynostosis – An evolving technique

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.

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.

Long-term aesthetic and photogrammetric outcomes in non-syndromic unicoronal synostosis: comparison of fronto-orbital distraction osteogenesis and fronto-orbital advancement and remodeling

BACKGROUND

Fronto-orbital advancement and remodeling (FOAR) is among the most common surgical approaches for unicoronal craniosynostosis (UCS), although some data demonstrate failure to achieve long-term aesthetic normalcy, leading some to seek alternative treatment paradigms such as fronto-orbital distraction osteogenesis (FODO). This study compares long-term aesthetic outcomes of patients with UCS treated with FOAR and FODO.

METHODS

Twenty patients (four males) with non-syndromic UCS presenting to our institution and undergoing distraction were compared to a matched cohort of 20 patients (six males) undergoing FOAR. Clinical photographs and ImageJ were used to quantify periorbital anatomy including palpebral fissures, pupil-to-brow distance (PTB), and margin-reflex distance (MRD₁) in pixels. Whitaker classification was blindly assigned by craniofacial surgeons.

RESULTS

Photogrammetric analysis and Mann-Whitney U tests demonstrated significantly improved postoperative symmetry in distraction patients for palpebral width (p = 0.020), MRD₁ (p = 0.045), and canthal tilt (p = 0.010). Average Whitaker classification scores between FOAR (1.94) and distraction (1.79) cohorts were similar (p = 0.374).

CONCLUSIONS

UCS patients demonstrated significant postoperative improvements in periorbital symmetry, with distraction patients demonstrating superior results in palpebral width and canthal tilt. FOAR and FODO patients achieved similar Whitaker classification scores. These cohorts will be followed until craniofacial maturity prior to making any definitive conclusions.

Posterior Calvarial Distraction in older paediatric population: single centre paediatric neurosurgery craniofacial unit outcomes

PURPOSE

Posterior calvarial distraction (PCD) is a safe and effective technique used to increase cranial vault volume and therefore reduce intracranial pressure in children with complex craniosynostosis. Optimal timing and method used for PCD is controversial. This procedure is usually performed in children younger than 2 years. Literature regarding calvarial distraction in older children is sparse and limited. We report our single-centre experience with PCD in children aged 6 and above to outline the applications, benefits and challenges of employing this technique in an older paediatric population.

METHODS

A retrospective analysis of a database on craniofacial cases from 2006 to 2021 was performed. Patients undergoing PCD were identified and children aged 6 and above at the time of operation were included. Data on demographics and clinical outcomes were obtained from electronic records and relevant imaging was reviewed. All cases were reviewed prior to a decision for surgery by the multidisciplinary craniofacial team (composed of neurosurgery, maxillofacial and plastics teams) and underwent surgery in our paediatric craniofacial centre.

RESULTS

Overall, 98 PCD cases were identified during the study period, of which 20 cases were identified as having undergone PCD at age 6 or above with mean age of 8.8 years (range 6-18). The most common indication was pansynostosis associated with raised intracranial pressure. Four cases had calvarial remodelling previously and represented with symptoms of raised intracranial pressure sometime after their initial surgery requiring PCD as rescue procedure. Average duration of inpatient stay was 5.85 days. The average duration of follow-up was 3.5 years (0.3 to 11 years). Mean distraction distance achieved was 22.5 mm (18-29 mm). Five patients experienced complications related to wound infection or distractor. Follow-up assessment in all patients demonstrated evidence of vault expansion and symptomatic improvement and resolution of intracranial pressure signs. Comparison with younger cohort did not reveal any difference in any parameters except lower rate of transfusion in the older cohort compared to young cohort (5% vs 38%).

CONCLUSION

Posterior calvarial distraction in older children is safe and effective for vault expansion and treatment of raised intracranial pressure in selected cases. A multidisciplinary craniofacial team approach is crucial for appropriate case selection and management in order to optimise outcomes.

Accelerated cranial distraction protocol for one-piece fronto-orbital distraction osteogenesis without bandeau in patients with craniosynostosis

This study aimed to compare the bony relapse ratios of standard and accelerated distraction protocols (ADP) in one-piece fronto-orbital distraction osteogenesis (DO). Patients with unilateral or bilateral coronal synostoses who underwent one-piece fronto-orbital DO were included. The accelerated cranial distraction protocol included a 3-day latency period and a distraction rate of 1-2 mm/day, followed by a 4-week consolidation period. Intracranial volume was measured using computed tomography (CT) before the surgery, at the end of the consolidation period, and 1 year after the removal of distractors. The intracranial volume changes and relapse ratios were calculated. This study included 32 patients; of these, 16 were included in each of the ADP and standard protocol (SP) groups. The mean ages were 1.4 years and 1.6 years in the ADP and SP groups, respectively (p = 0.895). In the ADP and SP groups, the expanded volumes were 270.9 ± 90.3 cm³ and 284.6 ± 149.7 cm³ (p = 0.91) and the growth-corrected expanded volumes were 162.1 ± 67.5 cm³ and 177.1 ± 105.2 cm³, respectively (p = 0.867). The relapse and growth-corrected relapse ratios showed no significant differences between the two groups, suggesting similar stability between the two protocols. The relapse ratios were 7.1 ± 4.8% and 7.3 ± 5.0% (p = 0.91) and the growth-corrected relapse ratios were -3.0 ± 3.3% and -2.4 ± 2.7%, respectively (p = 0.498). Within the limitations of the study, it seems that the ADP can shorten the distraction period without compromising stability. This may contribute to resolving the disadvantages and highlighting the advantages of DO.

Posterior Vault Distraction Outcomes in Patients with Severe Crouzon Syndrome Resulting from Ser347Cys and Ser354Cys Mutations

BACKGROUND

In this study, the authors present the outcomes of 4 patients with a severe form of Crouzon syndrome characterized by mutation of fibroblast growth factor receptor 2 (FGFR2) c.1040 C > G p.Ser347Cys or the pathogenic c.1061C > G p.Ser354Cys variant of FGFR2, who underwent posterior vault distraction osteogenesis (PVDO) to alleviate elevated intracranial pressure.

METHODS

Patients with diagnosed Crouzon syndrome who were found by genetic testing to have an FGFR2 c.1040 C > G p.Ser347Cys mutation or the c.1061C > G p.Ser354Cys variant were included. Outcome data and presence of hydrocephalus, Chiari Malformation type I (CMIs), and the presence/absence of a tracheostomy were recorded.

RESULTS

Three patients with the FGFR2 c.1040 C > G p.Ser347Cys mutation and 1 with the pathogenic FGFR2 c.1061C > G p.Ser354Cys variant were identified as having characteristics of severe Crouzon syndrome. The mean age at PVDO was 15 months and the mean posterior advancement was 20 mm. All 4 patients experienced sufficient relief of the elevated intracranial pressure from the PVDO to prevent the need for shunt placement, stabilize the ventricular dimensions (n = 2), and resolve the CMIs (n = 2). Intracranial pressure screening ruled out malignant cerebrospinal fluid volume increase.

CONCLUSIONS

PVDO effectively prevented hydrocephalus and resolved CMIs, successfully alleviating intracranial pressure and maximizing clinical outcomes for patients with severe Crouzon syndrome.

Treatment of Syndromic Craniosynostosis by Anterior and Posterior Vault Distraction Osteogenesis (A-PVDO)

OBJECTIVE

To explore the feasibility and therapeutic effect of anterior and posterior vault distraction osteogenesis (A-PVDO) in the treatment of infantile syndromic craniosynostosis.

METHODS

Between January 2017 and December 2019, 7 children with syndromic craniosynostosis underwent osteotomy with Piezo-surgery at our hospital. The first step was to harvest the frontal bone flap and the orbitofrontal bone flap. The second step was to separate the scalp and expose the posterior occipital. Osteotomy was performed on the occipital tubercle. Thereafter, 2 distractors were horizontally installed on the upper edge of the anterior cranial orbit, 2 distractors of 3 cm were installed on the posterior cranial bone. Meanwhile, lambdoidal sutures were fixed by titanium plates. Bone distraction was initiated on postoperative day 5 at the rate of 0.4 to 0.6 mm/day, twice per-day, for a total of 10 to 15 days. After 6 months, the distractors and the titanium plates were removed by secondary surgery.

RESULTS

The intracranial volume and posterior cranial morphology were recorded during the follow-up of 6 to 14 months (average = 12 months). The posterior craniums of 7 cases with lambdoidal sutures fixation were completely extended. The anterior cranial morphology was normal. All the cranial deformities were significantly improved. There were no severe complications, such as death, cranial necrosis, and intracranial infection.

CONCLUSIONS

A-PVDO is an ideal method for the treatment of severe syndromic craniosynostosis, which can achieve more natural appearance than anterior vault distraction osteogenesis or posterior vault distraction osteogenesis. Moreover, A-PVDO causes no severe complications and is suitable for the treatment of severe syndromic craniosynostosis.

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.

Severe craniolacunae and upper and lower extremity anomalies resulting from Crouzon syndrome, FGFR2 mutation, and Ser347Cys variant

Crouzon syndrome is a rare form of syndromic craniosynostosis (SC) characterized by premature fusion of the cranial and facial sutures, elevated intracranial pressure, varying degrees of ocular exposure due to exorbitism, and airway compromise caused by midface retrusion. Craniolacunae and upper and lower extremity anomalies are not frequently found in Crouzon syndrome. We present a girl with Crouzon syndrome caused by c.1040 C > G, p.Ser347Cys, a pathogenic mutation in the FGFR2 gene with atypical characteristics, including craniolacunae resembling severe Swiss cheese type of bone formation, and upper and lower extremity anomalies which are more commonly associated with Pfeiffer syndrome patients. Distinguishing between severe Crouzon syndrome patients and patients who have mild and/or moderate Pfeiffer syndrome can be challenging even for an experienced craniofacial surgeon. An accurate genotype diagnosis is essential to distinguishing between these syndromes, as it provides predictors for neurosurgical complications and facilitates appropriate family counseling related to long-term outcomes.

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.

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.

Posterior vault distraction technique: how I do it

Posterior cranial vault distraction is an effective technique when a significant increase in the intracranial volume is required in patients with craniosynostoses. This technique has been proven to be safe and time saving and usually is associated with low perioperative morbidity as well as low intraoperative bleeding. Herein a technique is presented starting from the preoperative planning, describing the surgical steps of the operation and the postoperative distraction protocol used by the authors. The authors present important tips and tricks aiming to minimise complications and undesired events.

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.

Upward vectors for osteogenic distraction treatment in secondary chronic intracranial hypertension in children undergoing scaphocephaly surgery: 2 cases reported

The occurrence of secondary synostosis of coronal sutures at distance from H-craniectomy surgery for scaphocephaly concerns about 10% of children. Intracranial hypertension in these children remains exceptional but generally requires a surgical reoperation. Two children aged 3 and 5- months- old had been operated for scaphocephaly by H-craniectomy in two different hospital centers. Their clinical follow-up described a partial persistence of dolichocephalic deformity and an impression of parietal stenosis. During their growth, chronic headaches appeared with a complaint expressed at the ages of 4 and 5 years. In both cases, ophthalmic examination revealed significant bilateral papillary edema without loss of visual acuity. The imaging assessment (CT-scan and MRI) showed the absence of Chiari malformation and venous abnormality. For both, there was a compression image of the parietal lobes in relation to the persistence of a temporoparietal synostosis. An osteogenic parietal distraction permitted a volumetric brain expansion consecutive to the skull and meninges remodeling in only 6 months, associated with a leap forward acquisition, a normalization of the ophthalmic examination, and a complete loss of headaches. In conclusion, this new approach could be used in the case of chronic intracranial hypertension consecutive to a secondary parietal synostosis after a scaphocephaly surgery.

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.

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.

National 30-Day Outcomes for Posterior Cranial Vault Distraction

BACKGROUND

Posterior vault distraction (PVD) can rapidly expand calvarial volume in infancy. Limited data exist regarding its perioperative and postoperative safety profile. This study sought to investigate the patient profile, outcomes, and safety of PVD using a national pediatric database.

METHODS

Posterior vault distraction patients between 2012 and 2016 were isolated from the National Surgical Quality Improvement Program Pediatric database. Patient background, perioperative outcomes, and risk factors were analyzed using chi-squared, t test analysis, and multivariate regression.

RESULTS

Ninety-four patients who underwent PVD were isolated with 67 ultimately meeting inclusion criteria for the study. The majority of patients undergoing PVD had limited other documented comorbidities. No patients required reoperation or 30-day readmission. There were no incidences of stroke, surgical site infection, or death. Subdividing outcomes by specialty, plastic surgeons performed PVD on significantly older patients than neurosurgeons (188 days vs 138 days, P = 0.008). Increasing age was associated with increasing operative time (P < 0.001). Furthermore, increasing age is associated with greater absolute transfusion requirements (P = 0.018) and higher, but not significant, risk of requiring any volume of blood transfusion (P = 0.105).

CONCLUSIONS

Posterior vault distraction is a safe procedure to rapidly expand calvarial volume in the setting of craniosynostosis. Increasing patient age is the strongest predictor for prolonged operative time and higher blood transfusion volumes.

Single-stage Total Cranial Vault Remodeling for Correction of Turricephaly: Description of a New Technique

Background:

Turricephaly is considered one of the most difficult cranial deformities to correct as addressing cranial height can result in increased intracranial pressure. We describe a new technique of total calvarial remodeling with bony transposition to simultaneously correct turricephaly and brachycephaly while preserving intracranial volume.

Methods:

A retrospective review of patients undergoing single-stage cranial vault remodeling by a single surgeon (J.G.M.) at a single center between 2007 and 2015 was performed. The procedure consists of a frontal bandeau followed by a 1 cm 360^o axial strip craniectomy. The strip is then rotated 90 degrees into a coronal orientation and interposed between fronto-parietal and parito-occipital segments. Modification for occipital widening can also be performed.

Results:

Six patients with turribrachycephaly underwent the procedure over the 8-year period. Four patients were operated at less than 1 year of age, one patient underwent surgery at 2 years, and one at 9 years. Mean operative time was 4 hours, and mean transfusion was 300cc. There were no major complications. Mean cranial height reduction achieved was 1.6 cm (range, 1.0–2.0 cm), and mean anterior–posterior expansion was 3.4 cm (range, 2.3–4.5 cm). Patients also showed improvement in supraorbital retrusion.

Conclusion:

Single-stage cranial vault remodeling with axial strip craniectomy and coronal interposition is safe and allows for simultaneous correction of turricephaly and brachycephaly while preserving intracranial volume.

Improvement of Color Vision Following Posterior Cranial Vault Distraction for Crouzon Syndrome

Crouzon syndrome (CS) is one of the craniosynostosis syndromes that leads to early fusion of cranial sutures and increased intracranial pressure. Intracranial hypertension is a serious complication that may lead to vision loss and cognitive impairment. Early detection and management are necessary to prevent complications. The authors present a patient with CS who underwent posterior cranial vault reconstruction with internal distraction after multiple episodes of headache and papilledema. The patient was unaware of any loss of color vision before the surgery; however, he noted an improvement in his color vision after the surgery. Color vision deficits may be an early sign of intracranial hypertension and finding these deficits using noninvasive testing methods may be an indication for early intervention.

Posterior Vault Distraction Osteogenesis in Nonsyndromic Patients: An Evaluation of Indications and Safety

PURPOSE

The purpose of this study was to evaluate the indications, safety, and short-term outcomes of posterior vault distraction osteogenesis (PVDO) in patients with no identified acrocephalosyndactyly syndrome (study) and to compare those to a syndromic cohort (controls).

METHODS

Demographic and perioperative data were recorded and compared across the study and control groups for those who underwent PVDO between January 2009 and December 2016. Univariate analysis was conducted using χ and Fisher exact tests for categorical variables, and Mann-Whitney U test for continuous variables.

RESULTS

Sixty-three subjects were included: 19 in the nonsyndromic cohort, 44 in the syndromic cohort. The cohorts had similar proportion of subjects exhibiting pansynostosis (42.1% of nonsyndromic versus 36.4% of syndromic, P = 0.667). The nonsyndromic cohort was significantly older (4.04 ± 3.66 years versus 2.55 ± 3.34 years, P = 0.046) and had higher rate of signs of raised intracranial pressure (68.4% versus 25.0%, P = 0.001) than the syndromic cohort. There was no significant difference in perioperative variables or rate of complications (P > 0.05). The mean total advancement distance achieved was similar, 27 ± 6 mm in the nonsyndromic versus 28 ± 8 mm in the syndromic cohort (P = 0.964). All nonsyndromic subjects with signs of raised intracranial pressure demonstrated improvement at an average follow-up of 22 months.

CONCLUSION

As in the syndromic patient, PVDO is a safe and, in the short-term, effective modality for cranial vault expansion in the nonsyndromic patient. The benefits and favorable perioperative profile of PVDO may therefore be extended to patient populations other than those with syndromic craniosynostosis.

Staged Raising of a Coronal Flap for Fronto-Orbital Advancement and Remodeling in Saethre-Chotzen Syndrome Complicated by Sinus Pericranii

This article reports the surgical management of a 3-month-old girl with Saethre-Chotzen syndrome, who presented with bicoronal synostosis and a large midline sinus pericranii with abnormal cerebral venous drainage via scalp veins. Raised intracranial pressure was demonstrated on monitoring, indicating the need for calvarial expansion necessitating a coronal access incision. A 2-staged delayed raising of the coronal flap was performed to reduce the potential risk of cerebral venous infarction. Monitoring for clinical sequelae and a computerised tomography venogram followed each of these procedures, demonstrating successful redirection of the venous drainage of the brain posteriorly. Finally, a successful fronto-orbital advancement and remodeling procedure was performed with no complications.

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.

Complications in Posterior Cranial Vault Distraction

BACKGROUND

The use of posterior cranial vault distraction for the treatment of elevated intracranial pressure is gaining popularity and is a standard for first-stage cranial expansion in syndromic craniosynostosis at many institutions. However, although the operation is faster and less complex than other cranial vault remodeling procedures, it is not without its own unique set of complications.

METHODS

We surveyed the published literature for case series and case control studies on posterior vault distraction. Complication rates and types for these series were tabulated and grouped by management. When outcomes were unclear, corresponding authors were contacted for clarification and treatment plans.

RESULTS

Eleven reports were found from a search of all the literature on posterior cranial vault distraction with a range of 1 to 22 included patients. The average age at surgery was 16.2 ± 11.8 months. Complication rates ranged from 12.5% to 100%, with the average of 30% of patients across all studies. The most common complications reported were cerebrospinal fluid leak or dural injury, followed by wound infections or device exposures, and device failure. There were no reported patient deaths or long-term morbidities.

CONCLUSIONS

Posterior cranial vault distraction is a relatively safe and effective therapy for the treatment of elevated intracranial pressure in the setting of syndromic craniosynostosis. The majority of described complications center on the interaction of the device with the dura, device extrusion, and infection. Extreme care must be used with the placement of these distraction devices and with handling of the dura at the osteotomy sites to ensure successful outcomes and avoid complications.

LEVELS OF EVIDENCE

III.

Outcomes of endoscopic suturectomy with postoperative helmet therapy in bilateral coronal craniosynostosis

OBJECTIVE Historically, bilateral frontoorbital advancement (FOA) has been the keystone for treatment of turribrachycephaly caused by bilateral coronal synostosis. Early endoscopic suturectomy has become a popular technique for treatment of single-suture synostosis, with acceptable results and minimal perioperative morbidity. Boston Children's Hospital has adopted this method of treating early-presenting cases of bilateral coronal synostosis. METHODS A retrospective review of patients with bilateral coronal craniosynostosis who were treated with endoscopic suturectomy between 2005 and 2012 was completed. Patients were operated on between 1 and 4 months of age. Hospital records were reviewed for perioperative morbidity, length of stay, head circumference and cephalic indices, and the need for further surgery. RESULTS Eighteen patients were identified, 8 males and 10 females, with a mean age at surgery of 2.6 months (range 1-4 months). Nine patients had syndromic craniosynostosis. The mean duration of surgery was 73.3 minutes (range 50-93 minutes). The mean blood loss was 40 ml (range 20-100 ml), and 2 patients needed a blood transfusion. The mean duration of hospital stay was 1.2 days (range 1-2 days). There was 1 major complication in the form of a CSF leak. The mean follow-up was 37 months (range 6-102 months). Eleven percent of nonsyndromic patients required a subsequent FOA; 55.6% of syndromic patients underwent FOA. The head circumference percentiles and cephalic indices improved significantly. CONCLUSIONS Early endoscopic suturectomy successfully treats the majority of patients with bilateral coronal synostosis, and affords a short procedure time, a brief hospital stay, and an expedited recovery. Close follow-up is needed to detect patients who will require a secondary FOA due to progressive suture fusion or resynostosis of the released coronal sutures.

Distraction Osteogenesis Update: Introduction of Multidirectional Cranial Distraction Osteogenesis

In this review, we discuss in detail our current procedure for treating craniosynostosis using multidirectional cranial distraction osteogenesis (MCDO). The MCDO method allows all phenotypes of skull deformity to be reshaped by distraction osteogenesis, except in patients who are 5 months of age or younger and patients with posterior cranial vault problems. We report the results of clinical data of 36 children with craniosynostosis who underwent MCDO between 2005 and 2014 in our institute. This method has the following benefits, such as a high flexibility of reshaping, shorter treatment period and less invasive secondary intervention. We also discuss the other distraction osteogenesis techniques that are used to treat craniosynostosis and compare them with MCDO. The preferred procedure for correction of craniosynostosis may depend on the patient's age, the extent of deformity, and the extent of correction achievable by surgery. We can arrange the combinations of various methods according to the advantage and disadvantage of each technique.

Piezosurgical Suturectomy and Sutural Distraction Osteogenesis for the Treatment of Unilateral Coronal Synostosis

Different surgical procedures are used for the treatment of synostosis. Among them, suturectomy and sutural distraction osteogenesis (SDO) are suitable for young infant patients. In this report, we present the case of a young infant patient with a clear synostosis of the left coronal suture, which was treated by piezoelectric suturectomy combined with SDO and 2 internal distractors. One-year follow-up showed good results. Thirty-six months after surgery, normal skull growth and shape were observed by 3D computed tomographic examination. No infection, bleeding, fistula, and other complications were observed. The results suggested that the treatment of unilateral coronal synostosis in young infant patient by piezosurgical suturectomy and SDO is to be preferred because of its simplicity and relatively minimal invasiveness.

Distraction Osteogenesis Technique for the Treatment of Nonsyndromic Sagittal Synostosis

Background

Historically, surgical treatment of children with a delayed presentation of cranial synostosis required complex cranial vault reconstruction. Recently, less invasive options for surgical correction, such as internal distraction osteogenesis, have been explored. In this study, we describe the successful management of delayed presentation of sagittal synostosis using distraction osteogenesis.

Methods

A bicoronal incision was made and 2 large rectangular osteotomies were performed bilaterally, involving the frontal, parietal, temporal and occipital bones. A 2 cm strut of bone over the sagittal sinus was preserved, creating bilateral free-floating bone segments. Two pairs of distractors were placed transversely, along the midline strut of bone, providing lateral distraction of these segments. This placement allowed maximum displacement at the apex of the cranial vault. Distraction was performed differentially at 1 mm per day anteriorly and 2 mm per day posteriorly, for a total of 17 days, allowing for a greater degree of expansion of the posterior vault. The consolidation phase lasted for 10 weeks. The distractors were removed via the same bicoronal incision and cranioplasty was performed to smooth prominent ridging at the margins of the distracted segments.

Results

The child’s cranial index improved from 0.67 preoperatively to 0.76 postoperatively. The overall vault contour was smooth with no bony defects. There was a significant cosmetic improvement of the child’s head shape. No major complications requiring reoperation or rehospitalization were encountered.

Conclusion

The use of distraction osteogenesis to laterally expand the cranial vault is a useful alternative in the treatment of delayed presentation, nonsyndromic, sagittal synostosis.

Cranial distraction osteogenesis: a proposal of minimal consolidation period

PURPOSE

Cranial distraction osteogenesis (DO) has many advantages for correcting skull deformities: Thus, DO is extensively used for the treatment of skull deformities. However, diverse, unexpected complications are associated with this procedure. In this study, we present the surgical outcomes and complications of DO. Moreover, we propose a modified protocol for DO to reduce complications.

METHODS

This is a retrospective study on managed patients that underwent DO between March 2008 and May 2013. Their clinical courses were reviewed. Distraction protocols were individually inspected, and the final surgical outcomes, including complications, were evaluated.

RESULTS

During the study period, a total of ten patients (seven boys and three girls) were treated at our institute. The median distraction period was 20.5 days (ranging from 17 to 50 days). The range of total distraction length was 19-22 mm. The median consolidation period was 96 days (ranging from 0 to 343 days). All patients achieved the goals of distraction. At follow-up evaluations, all patients, except one, showed good surgical outcomes in both head shape and neurologic symptoms. There were six patients with wound complications during the treatment period. Among them, the distractors were removed early in three patients. Interestingly, even these three patients, without a sufficient consolidation period, showed good outcomes.

CONCLUSIONS

Although DO has many merits for correcting skull deformities, it frequently causes severe wound complications. To reduce these complications, we propose a modified protocol with a minimal or even no consolidation period.

Venous hypertension in syndromic and complex craniosynostosis: the abnormal anatomy of the jugular foramen and collaterals

Why craniosynostosis patients develop elevated intracranial pressure (ICP) is still a mystery. Our aim was to investigate jugular foramen size and its relation to venous hypertension and elevated ICP. Secondly, we evaluated whether occipital collateral veins develop as a compensatory mechanism for elevated ICP. We conducted a prospective study in 41 children with craniosynostosis who underwent a 3D-CT-angiography. We evaluated the anatomical course of the jugular vein, the diameter of the jugular foramen and the relation to the presence of papilledema. Additionally, we studied the anatomical variations of the cerebral venous drainage system. The diameter of the jugular foramen was significantly smaller in our patients. Abnormal venous collaterals were most often observed in patients with Apert, Crouzon-Pfeiffer and Saethre-Chotzen syndrome, even in children under two years of age. There was no significant difference in the number of collateral veins in patients with or without papilledema. Collaterals appear to reflect an inborn abnormality of the venous system, rather than a compensating mechanism for elevated ICP. This study confirms the presence of jugular foraminal narrowing in craniosynostosis patients and an abnormal venous system, which may predispose to elevated ICP.

LEVEL OF EVIDENCE

Diagnostic II.

Posterior cranial vault distraction osteogenesis: evolution of technique

The rapid growth of the brain in the first few years of life drives the expansion of the cranial vault. This expansion occurs primarily at the cranial sutures; premature fusion of these results in growth restriction perpendicular to the axis of the suture. The result of this is physical deformation of the cranial and facial skeleton, as well as the distortion of the underling brain and its physiology. These patients can present with symptoms of raised intracranial pressure, neurodevelopmental delay, as well as the morphological features of craniosynostosis. Acquired conditions such as the slit ventricle syndrome may also result in cephalocranial disproportion with these clinical features. Traditional vault remodeling surgery is able to correct the physical abnormalities as well as correcting cephalocranial disproportion. Its limitations include the degree of scalp expansion achievable as well as resulting defects in the bone. The use of distraction osteogenesis of the cranial vault permits a controlled expansion in a predetermined vector in a gradual manner. When used in the calvarium, this combines the benefits of tissue expansion on the scalp, as well as stimulating the production of new bone, reducing the defects resulting from expansion. In this review, the authors describe some of the surgical considerations important to the use of this technique. This includes the relevant anatomy and technical aspects illustrated with the use of clinical cases. Finally, they present a summary of their experience and discuss the complications associated with cranial vault distraction osteogenesis.

Osteodistraction of mandibles with a small bone defect at the planned osteotomy site: a histological pilot study in dogs

AIM

To develop a treatment plan for cases in which a bone defect is located on the osteotomy line of mandibular osteodistraction (DO).

SUBJECTS AND METHODS

Bilateral DO was performed in 17 Mongrel dogs. Prior to surgery, the 34 hemi-mandibles were randomly allocated to three groups: C (n = 10; a standard DO was performed), D - G (n = 12; a bone defect was created on the DO osteotomy line), and D + G (n = 12; the bone defect on the osteotomy line was grafted). After one week of latency, 8 days of distraction, and 4 weeks of consolidation the animals were sacrificed, and the newly formed bone were examined.

RESULTS

In group C, two zones of immature trabecular bone originating from host bone margins were separated by a central fibrous zone. In group D + G uniform new bone formation of the entire distraction gap was observed. In group D - G the distraction gap was mainly filled with fibrous tissue. The values for the newly formed bone volume and trabecular thickness were not significantly different between groups D + G and C, but were higher than values in group D - G (p < 0.05).

CONCLUSION

When a mandibular defect is located at the site of distraction osteotomy, DO can be performed simultaneous with bone grafting of the defect.

A craniometric analysis of posterior cranial vault distraction osteogenesis

BACKGROUND

Posterior cranial vault distraction osteogenesis has replaced fronto-orbital advancement in some centers as the first-line treatment in patients with syndromic craniosynostosis. Despite this fact, little has been written about its craniometric effects on children with syndromic craniosynostosis.

METHODS

A retrospective review of all patients who underwent posterior distraction was performed. Patient demographic, perioperative data, and preoperative/postoperative computed tomographic scans were reviewed. Volumetric and craniometric indices were calculated and measured using commercial three-dimensional imaging software.

RESULTS

From 2008 to 2012, 22 patients underwent posterior vault distraction osteogenesis for suspected intracranial hypertension or severe turribrachicephaly. In 13 patients, this was the first cranial vault procedure performed, whereas eight had previous fronto-orbital advancement and one had parieto-occipital reshaping. Half of patients underwent posterior cranial vault distraction osteogenesis before age 1 year; the average age at surgery was 2.3 years (range, 0.3 to 14.1 years) and distraction length averaged 27.3 mm (range, 19 to 35 mm). Average length of surgery was 2.9 hours (range, 1.6 to 3.8 hours), and average blood loss was 400 ml (range, 200 to 600 ml). Total treatment length was 91 days (range, 48 to 147 days). Distraction length averaged 27.3 mm (range, 19 to 35 mm). Intracranial volume increase averaged 21.5 percent (range, 7.5 to 70.0 percent; p<0.0001) and 28.4 percent (range, 10.8 to 66.0 percent; p=0.01) in the subset of patients younger than 1 year. Posterior cranial height increased 12.2 percent (range, 0 to 35 percent; p=0.002), and basofrontal angle decrease averaged 3.9 percent (range, 0 to 12 percent; p=0.003), indicating a decrease in cranial height trajectory and improvement in frontal bossing.

CONCLUSIONS

Posterior cranial vault distraction is a safe and effective operation that may lower risk of intracranial hypertension and abnormal skull morphology. Interestingly, cranial morphological benefits were seen both anteriorly and posteriorly.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The role of distraction osteogenesis in the management of craniofacial syndromes

Distraction osteogenesis (DO) has been established as a useful technique in the correction of skeletal anomalies of the long bones for several decades. However, the use of DO in the management of craniofacial deformities has been evolving over the past 20 years, with initial experience in the mandible, followed by the mid-face and subsequently, the cranium. This review aims to provide an overview of the current role of DO in the treatment of patients with craniofacial anomalies.