Distraction osteogenesis in craniosynosotosis: technical note

220 - Syndromic Craniosynostosis

The aims of this study were to document the incidence of new-onset craniosynostosis (NOC) after posterior vault distraction osteogenesis (PVDO), to determine risk factors for the development of NOC, and to deduce the cranial ramifications of NOC. An institutional review board-approved retrospective review of all patients who underwent PVDO at the Children's Hospital of Philadelphia was performed. Demographics, perioperative data, as well as preoperative and postoperative three-dimensional computed tomographic scans were analyzed. Suture patency preoperatively and postoperatively was recorded.Thirty patients underwent PVDO for suspected increased intracranial pressure and/or severe turribrachicephaly from 2008 to 2013. Twenty-four patients had syndromic diagnoses. The average age at the time of PVDO was 2.03 years. Distraction distances ranged from 19 to 40 mm, with an average of 28.7 mm. Among the 19 patients who had patent lambdoid sutures before PVDO, new-onset lambdoid fusion was seen in 17 patients after PVDO (89.5%), whereas the suture remained open in 2 patients (10.5%). New-onset lambdoid fusion was not significantly associated with age at distraction (P = 0.28), sex (P = 0.47), length of distraction (P = 0.93), or diagnosis (P = 0.61). Similarly, new-onset sagittal synostosis was not associated with age at distraction (P = 0.06), sex (P = 0.64), length of distraction (P = 0.83), or diagnosis (P = 0.25). None of the patients who developed NOC had characteristic head shape changes such as mastoid bulges or scaphocephaly. New-onset lambdoid and sagittal synostoses occur frequently after PVDO. Although the diagnosis of NOC is obvious radiographically, the clinical importance of the diagnosis morphometrically, neurodevelopmentally, and in cranial growth has yet to be fully investigated.

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. 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. 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. 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.

The purpose of this study is to describe the technique and outcomes of posterior vault distraction osteogenesis (PVDO) in patients with syndromic and nonsyndromic craniosynostosis. Studies from MEDLINE, Scopus, and Cochrane Central Register of Controlled Trials were systematically searched for patients with posterior cranial vault distraction osteogenesis. Inclusion criteria encompassed all studies with 3 or more patients per cohort who underwent posterior cranial vault distraction osteogenesis and had a follow-up of at least 1 month. Patients with both syndromic and nonsyndromic synostosis were included. The risk of bias in nonrandomized studies of intervention tool (ROBINS-I) was applied. A total of 19 manuscripts with 403 patients met the criteria. All but one study included patients with syndromic craniosynostosis. In total, 5.9% of cases used one distractor, 72.5% two, 3.7% three, and 7.4% four. The distraction achieved ranged from 18.7 to 35mm with an average of 23.54mm. Distraction protocol was, on average, 1mm/d. The duration of the distractors from placement to extraction was 10.1 weeks. Follow-up after surgery was 27.09 months on average. Ninety-nine (26.3%) complications in 376 patients were reported, of which 31 required unplanned surgical intervention. Single-arm metanalysis of the complications associated with PVDO revealed 13.71 events (CI: 8.9-19.8) per 50 cases with moderate heterogeneity per Cochrane Q test (χ2=47.12 P<0.01) and I2 test (68%). PVDO is an effective technique to increase cranial vault volume. Factors such as distraction protocol selected based on the patient's needs and age at the time of surgery are crucial for successful outcomes. Furthermore, distraction protocols can be tailored to specific needs, permitting a patient-centered approach. Complications are variable both in incidence as well as severity.

Background: Craniosynostosis (CS) is defined as pre-mature fusion of one or more of the cranial sutures. CS is classified surgically as either simple or complex based on the number of cranial sutures involved. CS can also be classified genetically as isolated CS or syndromic CS if the patient has extracranial deformities. Currently, the link between clinical and genetic patterns of CS in the Saudi population is poorly understood.Methodology: We conducted a retrospective cohort study among 28 CS patients, of which 24 were operated and four were not. Clinical and genetic data were collected between February 2015 and February 2019, from consenting patient's families. The electronic chart data were collected and analyzed including patient demographics, craniofacial features, other anomalies and dysmorphic features, operative data, intra cranial pressure (ICP), parent consanguinity and genetic testing results.Results: The most common deformity in our population was trigonocephaly. The most performed procedure was cranial vault reconstruction with fronto-orbital advancement, followed by posterior vault distraction osteogenesis and suturectomy with barrel staving. Genetics analysis revealed pathogenic mutations in FGFR2 (6 cases), TWIST1 (3 cases), ALPL (2 cases), and TCF12 (2 cases), and FREM1 (2 case).Conclusion: Compared to Western countries, our Saudi cohort displays significant differences in the prevalence of CS features, such as the types of sutures and prevalence of inherited CS. The genomic background allows our phenotype-genotype study to reclassify variants of unknown significance. Worldwide, the sagittal suture is the most commonly affected suture in simple CS, but in the Saudi population, the metopic suture fusion was most commonly seen in our clinic. Further studies are needed to investigate the characteristics of CS in our population in a multicenter setting.

Surgery is performed for craniosynostosis to enlarge intracranial volume and improve cranial morphology. Endoscope-assisted suturectomy is one of the effective treatments. Compared with other techniques, it is reported to be low invasive and enables improvement of cranial volume and morphology at an early age. At the National Center for Child Health and Development (Tokyo, Japan), endoscope-assisted suturectomy is performed for all patients with craniosynostosis under the age of 3 months. Bone defects are sometimes observed several years after endoscope-assisted suturectomy. In syndromic bilateral coronal craniosynostosis patients in whom fused coronal sutures are removed, bone defects often remain in the temporal region. These may cause difficulty in setting the osteotomy line and placing distraction device for later monobloc advancement. In the present study, syndromic bilateral coronal craniosynostosis patients who underwent endoscope-assisted suturectomy between 2017 and 2022 at our hospital were retrospectively reviewed to investigate residual bone defects after the operation. As monobloc advancement, tongue-in-groove technique and placing internal distractors were assumed, and cranial bone defects between the ages of 3 and 5 years were evaluated in 3D by using image processing software. Five patients were included, and in 2 patients, the bone defects in the temporal regions were deemed large enough to interfere with making the bandeau or restrict the use of internal distractors for monobloc advancement. When performing suturectomy for syndromic craniosynostosis patients with midfacial concavity, careful surgical strategies that take into account future monobloc advancement should be considered.

Objective To explore the effect of distraction osteogenesis in the treatment of syndromic craniosynostosis. Methods The clinical data of 6 children with syndromic craniosynostosis from January 2014 to September 2018 were retrospectively analyzed. There were 5 males and 1 female, aged from 1 month and 21 days to 6 years and 1 month, with an average age of 30 months. There were 3 Crouzon syndrome, 1 Pfeiffer syndrome, 1 Vogt syndrome (ACS Ⅱ) and 1 Clove leaf skull syndrome. The distraction osteogenesis apparatus was used in this procedure. The distraction osteogenesis was prolonged twice a day, 0.4 mm each time, and the prolongation was stopped when the skull shape was significantly improved. Three-dimensional CT scans of the skull were reviewed after 6 months, suggesting that distraction osteogenesis was good, then the lengthener was removed. Complications were recorded, and extended distances were measured. Cranial indices before and after operation were compared to evaluate the efficacy, safety and feasibility of the operation. Results The procedure of operation and traction was successful in all 6 children. There were no complications such as cranial spinal fluid (CSF) leakage or intracranial infection occurred. The increased distance was (19.1±3.3) mm, ranging from 15.2 to 25.6 mm. The preoperative cranial index was 89.6 ±7.3, while the postoperative cranial index was 74.2 ±3.6. All patients were followed up from 3 to 20 months, with the average of 14 months. The posterior cranial flatness was improved, and the patients were satisfied with the surgical results. Conclusions Distraction osteogenesis is effective and reliable in treating the premature fusion of cranial suture, and it produces excellent result with low rate of CSF leak and infection. Key words: Osteogenesis, distraction; Cranial flap; Craniosynostosis; Syndrome

Comparison of safety outcomes between bi-coronal and direct approaches for device removal in patients treated with distraction osteogenesis for craniosynostosis

Objective: Posterior vault remodeling by distraction osteogenesis is a relatively new technique used for initial correction of turribrachycephaly in children with bicoronal craniosynostosis. We present a new potential complication from this procedure; a case of pan-suture synostosis subsequent to posterior vault distraction. Methods: We report an infant girl who presented with bicoronal synostosis in the setting of Saethre-Chotzen syndrome. She underwent posterior vault distraction and was distracted a total of 34 millimeters, with successful osteogenesis at the site. Results: One year postoperatively, the patient was found to have incidental, asymptomatic pan-suture synostosis on computed tomography. Conclusions: To our knowledge, this is the first reported case of delayed craniosynostosis after posterior vault distraction in the literature. The possible pathogenesis and significance of this case are discussed with a review of the current literature.

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Craniosynostosis is defined as the premature fusion of one or more cranial sutures, which can present as an isolated defect or as a part of a syndrome with other anomalies (American Family Physician 69:2863–2870, 2004). Sagittal suture is the most common suture involved in craniosynostosis (American Family Physician 69:2863–2870, 2004). Preoperative planning and patient education is essential for an ideal esthetic result and patient satisfaction. A variety of surgical techniques have been described, depending on the age of the patient and the severity of the deformity. These range from strip and Pi craniectomies, to extensive vault remodeling. Recently, endoscopically assisted procedures and distraction osteogenesis followed by helmet therapy have gained advocates.

Callus Distraction Versus Single-Stage Lengthening With Bone Graft for Treatment of Brachymetatarsia: A Systematic Review

BackgroundConventionally, vector guidance for internal distractor placement during cleft maxillary distraction osteogenesis (DO) is done using vector guidance splint. Vector guidance splint cannot be fabricated if occlusion is not decompensated for model surgery.SolutionUsing mandibular occlusal plane as anatomical reference, vector guidance oral prosthesis is fabricated to guide distractor placement and vector determination, in cases where model surgery is not possible.What we do that is newVector guidance oral prosthesis is a new prototype produced to guide maxillary DO without the need of model surgery.

Cranial Deformation in Craniosynostosis: A New Explanation