Eyeing Risks: A Critical Analysis of the Use of Periorbital Steroids in Fronto-orbital Advancement.

OBJECTIVE: To evaluate the outcomes associated with two techniques of periorbital steroid administration in bilateral fronto-orbital advancement (FOA). DESIGN: Multi-institutional retrospective chart review. SETTING: Two high volume, tertiary US craniofacial centers. PATIENTS, PARTICIPANTS: Patients who underwent FOA between 2012 and 2021. INTERVENTIONS: Patients were divided into three cohorts based on method of steroid administration. Groups GEL and INJ represent those who received steroids in the form of triamcinolone soaked gelfoam or direct injection of dilute triamcinolone to the frontal/periorbital region, respectively. Group NON did not receive any periorbital steroids. MAIN OUTCOME MEASURE(S): Peri-operative outcomes including hospital length of stay and complications were evaluated based on method of periorbital steroid administration. Variables predictive of infectious complications were assessed using stepwise logistic regression. RESULTS: Four hundred and twelve patients were included in our sample (INJ:249, GEL:87, NON:76). Patients in the INJ group had a higher ASA class (P < .001) while patients in the NON group were significantly more likely to be syndromic (P < .001) and have multisuture craniosynostosis (P < .001). Rate of infectious complications for each cohort were NON: 2.6%, INJ: 4.4%, and GEL: 10.3%. There was no significant difference between groups in hospital length of stay (P = .654) or rate of post-operative infectious complications (P = .061). Increased ASA class (P = .021), increased length of stay (P = .016), and increased intraoperative narcotics (P = .011) were independent predictors of infectious complications. CONCLUSIONS: We identified a dose-dependent relationship between periorbital steroids and rate of postoperative infections, with key contributions from ASA class, hospital length of stay, and dose of intraoperative narcotics.

Bilateral Cleft lip Simulation.

OBJECTIVE: To evaluate the features, anatomic accuracy, and educational value of a high-fidelity bilateral cleft lip simulator. DESIGN: Evaluation of the simulator by expert cleft surgeons after performing a simulated bilateral cleft lip repair. SETTING: The simulator was evaluated by the surgeons during the Latin American Craniofacial Association meeting. PARTICIPANTS: Eleven experienced cleft surgeons evaluated the simulator. The cleft surgeons were selected based on their availability during the meeting. INTERVENTIONS: The participants performed a simulated bilateral cleft lip repair. They were each provided with a questionnaire assessing the simulator's features, realism and value as a training tool. MAIN OUTCOME MEASURE (S): The main outcome measure are the scores obtained from a Likert-type questionnaire assessing the simulators features, realism and value. RESULTS: Overall, the surgeons agreed with the simulator's realism and anatomic accuracy (average score of 3.7 out of 5). Overall, the surgeons strongly agreed with the value of the simulator as a training tool (average score of 4.6 out of 5). CONCLUSIONS: A high-fidelity bilateral cleft lip simulator was developed that is realistic and valuable as a training tool. The simulator provides a comprehensive training platform to gain hands-on experience in bilateral cleft lip repair before operating on real patients.

Magnitude of Horizontal Advancement is Associated With Apnea Hypopnea Index Improvement and Counter-Clockwise Maxillary Rotation After Subcranial Distraction for Syndromic Synostosis.

PURPOSE: Subcranial midface distraction is used to treat central midface deficiency in syndromic synostosis. Our aim was to determine which maxillary movements were associated with improvement in measures of obstructive sleep apnea. METHODS: This was a retrospective cohort study that reviewed patients with syndromic midface retrusion and documented sleep apnea who underwent subcranial midface distraction via either Le Fort 3 osteotomy or Le Fort 2 osteotomy with zygomatic repositioning. The predictor variables measured on cephalograms were the magnitude and direction of midface and mandibular movements. The primary outcome was the change in the apnea hypopnea index (AHI) from polysomnography before and after surgery. The secondary outcomes were volumes of upper airway containing bone spaces calculated from computed tomography scans. Data analysis included linear regression to estimate the effect of distraction vectors on bone space volumes and AHI changes. RESULTS: We included 18 patients primarily with Crouzon or Apert syndrome. The magnitude of distraction in a horizontal direction was the most significant factor for AHI improvement and primarily expanded the nasopharyngeal space, but with a smaller impact on the oral cavity space. Clockwise palate rotation was most influenced by a downward direction of distraction, with 24° below horizontal creating a neutral advancement. The greater the magnitude of advancement, the more likely a counterclockwise rotation was observed. CONCLUSIONS: Horizontal magnitude of advancement had the greatest impact on AHI improvement. Vertical lengthening and closure of anterior open bite deformities can be done without compromising airway results as long as total advancement is not compromised. Palate rotation is best controlled by a downward distraction vector, but counterclockwise rotation increases with greater advancement.

Cranial growth in isolated sagittal craniosynostosis compared with normal growth in the first 6 months of age.

Sagittal craniosynostosis (SCS), the most common type of premature perinatal cranial suture fusion, results in abnormal head shape that requires extensive surgery to correct. It is important to find objective and repeatable measures of severity and surgical outcome to examine the effect of timing and technique on different SCS surgeries. The purpose of this study was to develop statistical models of infant (0-6 months old) skull growth in both normative and SCS subjects (prior to surgery). Our goal was to apply these models to the assessment of differences between these two groups in overall post-natal growth patterns and sutural growth rates as a first step to develop methods for predictive models of surgical outcome. We identified 81 patients with isolated, non-syndromic SCS from Seattle Children's Craniofacial Center patient database who had a preoperative CT exam before the age of 6 months. As a control group, we identified 117 CT exams without any craniofacial abnormalities or bone fractures in the same age group. We first created population-level templates from the CT images of the SCS and normal groups. All CT images from both groups, as well as the canonical templates of both cohorts, were annotated with anatomical landmarks, which were used in a growth model that predicted the locations of these landmarks at a given age based on each population. Using the template images and the landmark positions predicted by the growth models, we created 3D meshes for each week of age up to 6 months for both populations. To analyze the growth patterns at the suture sites, we annotated both templates with additional semi-landmarks equally spaced along the metopic, coronal, sagittal and lambdoidal cranial sutures. By transferring these semi-landmarks to meshes produced from the growth model, we measured the displacement of the bone borders and suture closure rates. We found that the growth at the metopic and coronal sutures were more rapid in the SCS cohort than in the normal cohort. The antero-posterior displacement of the semi-landmarks also indicated a more rapid growth in the sagittal plane in the SCS model than in the normal model. Statistical templates and geometric morphometrics are promising tools for understanding the growth patterns in normal and synostotic populations and to produce objective and reproducible measurements of severity and outcome. Our study is the first of its kind to quantify the bone growth for the first 6 months of life in both normal and sagittal synostosis patients.

National Database Reported Outcomes Following Craniosynostosis Reconstruction.

BACKGROUND: While there has been ample interest and literature published regarding craniosynostosis surgical technique, there are few reports on adverse hospital and health system outcomes. The purpose of this study was to describe rate of and risk factors for complications, and adverse outcomes following craniosynostosis reconstruction. METHODS: This study retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Pediatric database and identified all patients undergoing craniosynostosis repair from 2012 to 2016. Univariate logistic regression analysis was used to identify significant associations between preoperative risk factors and adverse outcomes. Multivariate logistic regression analysis was then used to identify independent risk factors and causes of prolonged operative times, transfusions, reoperation, prolonged length of hospital stays, and readmission. RESULTS: There were 3924 patients included who underwent craniosynostosis repair, of whom 1732 underwent frontoorbital advancement and 2192 underwent cranial vault remodeling. Transfusion was the most common NSQIP reportable outcome, occurring for 66.5% of all patients. The incidence of reoperation was 2.4% and readmission was 3.0%. CONCLUSION: This study provides a large descriptive analysis of craniosynostosis repair throughout the United States. Largely nonmodifiable patient risk factors lead to worse health system metrics, with young age, gastrointestinal comorbidities, American Society of Anesthesiologist scores of 3 and greater, reoperation, and a prolonged length of stay as independent risk factors for readmission. This analysis can be used to identify the standard of practice in synostosis care and enhance the implementation of ancillary care services to provide safe and cost-effective care for patients undergoing craniosynostosis repair.

Timing of Ossification of the Anterior Skull Base in Syndromic Synostosis.

The anterior skull base undergoes a progressive ossification after birth. This has implications on the epidural dissection of early trans-craniofacial osteotomy procedures such as monobloc advancements. Our purpose was to determine the rate of ossification in syndromic synostosis patients relative to a normal cohort to establish when maturation of the anterior skull base is complete. The authors analyzed CT scans from 35 patients with Crouzon, Apert or Pfeiffer syndrome, and 84 patients without any craniofacial anomaly between the ages of 0 and 6 years. The non-ossified anterior skull base area was measured using 3D Slicer. The authors compared the sizes of the defects at different ages between the three syndromes and with the control group using Mann-Whitney test. Significance was set at P < 0.05. All patients less than 12 months of age had a measurable defect anterior to the cribriform whereas patients greater than five years of age had full ossification of the anterior skull base with no evidence of defect. The relationship of defect size and age at scan was non-linear, with most defects closing rapidly in the first six months. The temporal closure pattern of the defect was similar between the three syndromes and the control group with no significant difference. Our findings indicate that syndromic children undergo skull base maturation at the same rate as non-syndromic cases, with the majority ossified by three years of age. Anterior skull base surgeries performed before three years should optimize visualization of this area during dissection.

A genotype-specific surgical approach for patients with Pfeiffer syndrome due to W290C pathogenic variant in FGFR2 is associated with improved developmental outcomes and reduced mortality.

PURPOSE: Among children with FGFR2-associated Pfeiffer syndrome, those with the W290C pathogenic variant (PV) are reported to have the worst clinical outcomes. Mortality is high, and severe neurocognitive impairment has been reported in all surviving patients. However, it is unclear whether these poor outcomes are an unavoidable consequence of the PV itself, or could be improved with a genotype-specific treatment approach. The purpose of this report is to describe the more intensive surgical approach used for each of the three patients with W290C PV in FGFR2 at our center, all of whom survived and have normal neurocognitive functioning. METHODS: Retrospective chart review. RESULTS: In contrast to other patients with Pfeiffer syndrome at our center, all three patients who were subsequently found to have a W290C PV required a similar and more aggressive approach based on early cephalocranial disproportion. In contrast to previously reported W290C cases, each of our three patients survived and demonstrate normal neurocognitive functioning. CONCLUSION: While previously reported outcomes in W290C-associated Pfeiffer syndrome have been extremely poor, we present three patients who underwent an intensive surgical approach and have normal development. This suggests that a personalized and aggressive surgical approach for children with W290C PV may dramatically improve clinical outcome.

Single suture craniosynostosis: Identification of rare variants in genes associated with syndromic forms.

We report RNA-Sequencing results on a cohort of patients with single suture craniosynostosis and demonstrate significant enrichment of heterozygous, rare, and damaging variants among key craniosynostosis-related genes. Genetic burden analysis identified a significant increase in damaging variants in ATR, EFNA4, ERF, MEGF8, SCARF2, and TGFBR2. Of 391 participants, 15% were found to have damaging and potentially causal variants in 29 genes. We observed transmission in 96% of the affected individuals, and thus penetrance, epigenetics, and oligogenic factors need to be considered when recommending genetic testing in patients with nonsyndromic craniosynostosis.

Le Fort II Distraction With Zygomatic Repositioning: A Technique for Differential Correction of Midface Hypoplasia.

Severe midface hypoplasia is frequently addressed with subcranial midface advancement at the Le Fort II or Le Fort III level. Le Fort II advancement has a predominant affect on the vertical and sagittal positioning of the nasomaxillary complex; in contrast, the Le Fort III advancement allows for correction of zygomatic position and exorbitism. In this report, the authors described a technique for correction of exorbitism which concomitantly addresses central midface vertical and sagittal deficiency. The technique involves a combination of a Le Fort III osteotomy with a Le Fort II distraction. The Le Fort III osteotomy allows repositioning and fixation of the zygomas to correct lateral hypoplasia and exorbitism, maintaining the globes in a more functional position. The Le Fort II distraction allows for movement of the central midface independent of the lateral orbits and zygomas, correcting the sagittal and vertical position without orbital distortion. With the medial canthal apparatus attached to the Le Fort II segment and the lateral canthus attached to the stabilized lateral orbits, the differential movement achieved can also have a favorable effect on palpebral fissure orientation.

Distraction Osteogenesis Normalizes Mandibular Body-Symphysis Morphology in Infants With Robin Sequence.

PURPOSE: To evaluate changes in mandibular morphology in infants with Robin sequence (RS) after mandibular distraction osteogenesis (MDO) and compare the post-distraction morphology with that in infants without RS and infants with RS who had not undergone MDO. MATERIALS AND METHODS: Infants with RS treated with MDO were retrospectively evaluated over a 12-year period. All patients had pre-distraction and end-consolidation maxillofacial computed tomograms. Morphologic features of the mandible were divided into ramus and condyle, body and symphysis, and composite measurements. Post-distraction RS mandibular morphology was compared with pre-distraction morphology, as well as to age-matched infants without RS and age-matched infants with RS who had not undergone MDO. Comparisons were done using nonparametric paired-samples analyses. RESULTS: During the study period, 17 patients with RS treated with MDO met the inclusion criteria for the study. The mean ages at distraction and end-consolidation were 1.95 ± 3.24 and 8.46 ± 5.99 months, respectively. The post-MDO mandible was significantly different from the pre-MDO mandible with regard to the ramps-condyle unit and body-symphysis measurements, including development of a more parabolic mandibular arch form (P ≤ .001). Compared with age-matched non-RS infant mandibles, the post-distraction RS mandibles had similar morphologies. Compared with age-matched non-MDO RS mandibles, the post-distraction mandibles had significantly different morphologies anterior to the gonial angle, including a more parabolic arch form (P ≤ .006). CONCLUSIONS: MDO normalized mandibular morphology in infants with RS, with the greatest effect on measurements anterior to the gonial angle.

Defining and Correcting Asymmetry in Isolated Unilateral Frontosphenoidal Synostosis: Differences in Orbital Shape, Facial Scoliosis, and Skullbase Twist Compared to Unilateral Coronal Synostosis.

INTRODUCTION: Isolated frontosphenoidal synostosis (FS) is a rare cause of fronto-orbital plagiocephaly that can be challenging to distinguish from isolated unicoronal synostosis (UC). The purpose of this paper is to analyze differences in fronto-orbital dysmorphology between the 2 conditions, to describe approaches for surgical correction, and to report surgical outcomes between FS and UC patients in a casecontrol fashion. METHODS: Patients treated for craniosynostosis over a 12-year period at our institution were retrospectively evaluated under institutional review board approval. Frontosphenoidal synostosis patients who underwent bilateral fronto-orbital correction of anterior plagiocephaly with minimum 2-year follow-up, adequate pre-, and minimum 2-year postoperative computed tomography scans were included in the case-control portion of the study. These patients were randomly age-matched to UC patients meeting the same inclusion criteria. Preoperative and postoperative orbital shape and volumetric analysis was performed using Mimics software. RESULTS: Twelve FS patients were treated during the study period. Seven of these patients met casecontrol inclusion criteria with average follow-up of 47.5 months. The characteristic FS orbit was a relatively wide, short, and shallow trapezoid, while the characteristic UC orbit was a relatively narrow, tall, and deep parallelogram. Frontosphenoidal synostosis orbits were significantly wider, shorter, shallower, and smaller than UC orbits. Surgical correction tailored to the differential dysmorphologies resulted in statistical equalization of these differences between affected and contralateral control orbits at follow-up, with the exception of UC orbital width, which remained significantly narrower than unaffected contralateral control. One patient in each group required cranioplasty for skull defects at follow-up, while no patient underwent surgical readvancement. CONCLUSIONS: Frontosphenoidal synostosis and UC orbital shape differ significantly, and can be normalized using fronto-orbital advancement tailored to the distinct orbital dysmorphologies of these 2 groups.

Defining mandibular morphology in Robin sequence: A matched case-control study.

Robin Sequence (RS) is classically defined as the triad of micrognathia, glossoptosis, and airway obstruction. While there remains significant debate over diagnostic criteria for severity, there is consensus regarding micrognathia as a defining feature of the condition. The purpose of this study was to compare mandibular morphology among infants and children with RS to infants and children without RS using maxillofacial computed tomography. Our hypothesis was that there are discrete morphologic differences between RS and non-RS mandibles. Our goal was to determine if there are defined and measureable differences in RS mandible shape that can be used in defining the sequence. We identified 20 cases with RS and 20 age- and sex-matched controls without RS. Linear, angular, and composite measurements were obtained for each patient. Cases had shorter mandibular sagittal lengths (-27%, p = 0.001), shorter inferior border arc lengths (-11.5%, p = 0.002), steeper gonial angles (+10.5%, p < 0.001), and narrower symphyseal angles (-11.5%, p < 0.001). Mandibular shape in RS was more rounded/elliptical (p < 0.001) and infants with RS had a significantly smaller submental cross-sectional area (-29.4%, p < 0.001). These shape differences anterior to the gonial angle of the mandible appear to be a defining morphologic feature in RS.

Management of the Repeatedly Failed Cranioplasty Following Large Postdecompressive Craniectomy: Establishing the Efficacy of Staged Free Latissimus Dorsi Transfer/Tissue Expansion/Custom Polyetheretherketone Implant Reconstruction.

BACKGROUND: Postdecompressive craniotomy defect management following failed prior cranioplastyis challenging. The authors describe a staged technique utilizing free muscle transfer, tissue expansion, and custom polyetheretherketone (PEEK) implants for the management of previously failed cranioplasty sites in patients with complicating local factors. METHODS: Consecutive patients with previously failed cranioplasties following large decompressive craniectomies underwent reconstruction of skull and soft tissue defects with staged free latissimus muscle transfer, tissue expansion, and placement of custom computer-aided design and modeling PEEK implants with a 'temporalis-plus' modification to minimize temporal hollowing. Implants were placed in a vascularized pocket at the third stage by elevating a plane between the previously transferred latissimus superficial fascia (left on the skin) and muscle (left on the dura/bone). Patients were evaluated postoperatively for cranioplasty durability, aesthetic outcome, and complications. RESULTS: Six patients with an average of 1.6 previously failed cranioplasties underwent this staged technique. Average age was 33 years. Average defect size was 139 cm. Average time to procedure series completion was 14.9 months. There were no flap failures. One patient had early postoperative incisional dehiscence following PEEK implant placement that was managed by immediate scalp flap readvancement. At 21.9 month average follow-up, there were no cranioplasty failures. Three patients (50%) underwent 4 subsequent refining outpatient procedures. All patients achieved complete coverage of their craniectomy defect site with hear-bearing skin, acceptable head shape, and normalized head contour. CONCLUSIONS: The described technique resulted in aesthetic, durable craniectomy defect reconstruction with retention of native hear-bearing scalp skin in a challenging patient population.

Safety of Open Cranial Vault Surgery for Single-Suture Craniosynostosis: A Case for the Multidisciplinary Team.

INTRODUCTION: Single Suture Craniosynostosis (SSC) occurs in 1 in 2,500 live births and is the most common type of craniosynostosis treated in most centers. Surgical treatment has evolved over the past century and open techniques are tailored to the specific suture type. Additionally, the concept of multi-disciplinary team care has proliferated and is becoming the standard of care for SSC. The combination of these evolutions, we believe, has improved the safety of cranial vault surgery for SSC. METHODS: A retrospective review of patients participating in the Infant Learning Project at Seattle Children's Hospital who underwent cranial vault surgery for treatment of SSC between 2002 and 2006 was performed. Pre-operative assessment, surgical techniques, anesthetic and intraoperative events and both intra-operative and post-operative adverse events were analyzed. RESULTS: Eighty eight patients fulfilled the inclusion criteria (42 sagittal, 23 metopic, 19 unicoronal, 4 lambdoid). Length of procedure varied (FOA 5.2 hrs, modified pi 2.5 hrs, total vault 4.9 hrs and switch cranioplasty 4.6 hrs), as did transfusion amount (FOA 385 mL, modified pi 216 mL, total vault 600 mL, switch cranioplasty 207 mL) although 99% of patients received a transfusion of some sort. There were no deaths and no major intraoperative complications. Minor events include; ET tube malposition (1), desaturation (1), acidosis (1), hypothermia (9), coagulopathy (2), Hct < 25 (55). Average hospital stay was 3.4 days with no major post-operative complications. One patient was readmitted to the ICU and 1 had a scalp hematoma, but no patients returned to the operating room within 6 months after surgery. DISCUSSION: The surgical treatment of SSC has evolved from lengthy, risky procedures to become almost routine at most craniofacial centers. Additionally, the care for patients with SSC has evolved from a single provider to a multidisciplinary team concept based around protocols for workup, delivery of anesthesia, streamlined surgical procedures and post-operative care and assessment. This evolution has given open cranial vault surgery for SSC an acceptable safety profile.

Preoperative Imaging and Surgical Findings in Pediatric Frontonasal Dermoids.

OBJECTIVE: To review cases of congenital frontonasal dermoids to gain insight into the accuracy of preoperative computed tomography (CT) and magnetic resonance imaging (MRI) in predicting intracranial extension. METHODS: This retrospective study included all patients who underwent primary excision of frontonasal dermoids at an academic children's hospital over a 23-year period. Preoperative presentation, imaging, and operative findings were reviewed. Receiver operating characteristic (ROC) statistics were generated to determine CT and MRI accuracy in detecting intracranial extension. RESULTS: Search queries yielded 129 patients who underwent surgical removal of frontonasal dermoids over the study period with an average age of presentation of 12 months. Preoperative imaging was performed on 122 patients, with 19 patients receiving both CT and MRI. CT and MRI were concordant in the prediction of intracranial extension in 18 out of 19 patients. Intraoperatively, intracranial extension requiring craniotomy was seen in 11 patients (8.5%). CT was 87.5% sensitive and 97.4% specific for predicting intracranial extension with an ROC of 0.925 (95% CI [0.801, 1]), whereas MRI was 60.0% sensitive and 97.8% specific with an ROC of 0.789 (95% CI [0.627, 0.950]). CONCLUSION: This is the largest case series in the literature describing a single institution's experience with frontonasal dermoids. Intracranial extension is rare and few patients required craniotomy in our series. CT and MRI have comparable accuracy at detecting intracranial extension. Single-modality imaging is recommended preoperatively in the absence of other clinical indications. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:1961-1966, 2024.

Making the diagnosis: metopic ridge versus metopic craniosynostosis.

INTRODUCTION: The metopic suture is the only calvarial suture which normally closes during infancy. Upon closure, a palpable and visible ridge often forms which can be confused with metopic craniosynostosis. Metopic ridging (MR) is treated nonsurgically while metopic craniosynostosis (MCS) is treated surgically. Differentiating between the two is paramount; however, consensus is lacking about where a clear diagnostic threshold lies. The goal of this study is to describe the physical examination and CT scan characteristics which may help to differentiate between physiological closure of the metopic suture with ridging (MR) and MCS. METHODS: A retrospective chart review of all patients seen at Seattle Children's Hospital between 2004 and 2009 with the diagnosis of either MCS or MR (n = 282) was performed. Physical examination characteristics described by diagnosing practitioners were analyzed. Clinical photos were assessed by 3 expert raters to determine the importance of these characteristics. CT scan findings were abstracted and compared between the two diagnoses. RESULTS: The "classic" triad of narrow forehead, biparietal widening, and hypotelorism was present in only 14% of patients with MCS. Ninety-eight percent of patients in both groups had a palpable metopic ridge. The photographic finding of narrow forehead and pterional constriction was present in all patients with MCS, but only in 11.2% and 2.8% of patients with MR. On CT scan, the presence of 3 or more MCS findings was diagnostic of MCS in 96% of patients. Patients with MCS were more likely to present before 6 months of age (66% vs. 32%). CONCLUSIONS: Patients with MCS tend to present earlier than those with MR. Upon physical examination, the relationship between the lateral frontal bone and the lateral orbit is important in distinguishing between the two diagnoses. A CT scan can be helpful in making the diagnosis not to confirm a closed suture but to identify 3 or more MCS characteristics.

Pediatric Cranial Vault and Skull Base Fractures.

Cranial vault and skull base fractures in children are distinctly different from those seen in adults. Pediatric skull fractures have the benefit of greater capacity to remodel; however, the developing pediatric brain and craniofacial skeleton present unique challenges to diagnosis, natural history, and management. This article discusses the role of surgical treatment of these fractures, its indications, and techniques.

Direct Remodeling of Occipital Bullet Deformity in Sagittal Synostosis Improves Two-Year Posterior Morphology After Modified Pi Procedure.

BACKGROUND: Modifications of the Pi craniectomy technique are meant to address the occipital bullet deformity of sagittal synostosis but it is not clear if they result in persistent improvement. Our purpose was to use morphometric analysis to determine if a low occipital osteotomy with verticalization results in improved occipital shape after a modified pi procedure two years after surgery. METHOD: We performed a retrospective cohort study comparing modified Pi technique with and without a low occipital osteotomy with verticalization immediately and two years after surgery relative to age-matched normal controls. We used anthropometric measures and population-level anatomical templates using multivariate template construction script from Advanced Normalization Tools for comparison between groups. A subgroup analysis was performed for severe occipital bullet deformity at presentation. RESULTS: We observed stable improvement in the angle of the inferior occiput with the occipital remodeling modification that persisted two years after surgery. This improvement was seen in the entire cohort and was greater in the severe sub-group analysis. Complications and blood transfusion volumes were not different between the two techniques. The LOOV group demonstrated improved posterior vertical height and cephalic index immediately after surgery, but these did not persist two years later. CONCLUSION: Occipital remodeling improves the bullet deformity but does not affect posterior vertical height two years after surgery. We recommend direct inferior occipital remodeling when using the Pi technique for young patients with acute occipital incline angles and occipital constriction.

Cranial Shape Changes in Nonsyndromic Unilateral Lambdoid Synostosis after Open Posterior Vault Remodeling.

BACKGROUND: The purpose of this study was to quantify change in cranial morphology in patients with nonsyndromic unilateral lambdoid craniosynostosis (ULC) from presentation (t0), after open posterior switch-cranioplasty (t1), and at 2-year follow-up (t2). METHODS: Volumetric, linear, and angular analysis were performed on computed tomographic scans at the three time points and against normal control subjects. Significance was set at P < 0.05. RESULTS: Twenty-two patients were included. ULC cranial vault asymmetry index was higher than in control subjects before surgery (6.22 ± 3.55) but decreased after surgery (3.00 ± 2.53) to become comparable with the normal asymmetry range present in the controls. After surgery, both diagonals increased, but more on the fused side. In the 2 years after surgery, both diagonals in patients with ULC grew proportionately, but the fused diagonal remained slightly shorter than the patent side. Total cranial volume was higher in patients with ULC than in control subjects after surgery but became comparable at t2. Cranial base angulation improved by t2 but did not approach normal, and ear position remained unchanged. The facial twist was higher than in controls at t0 and t1 but was comparable at t2. Coronal asymmetry improved with surgery but remained undercorrected at t2, with the greatest residual asymmetry at opisthion. CONCLUSIONS: Open-switch cranioplasty normalizes cranial vault asymmetry index by increasing the fused cranial diagonal more than the patent side and is stable at 2 years. Skull base twist does not normalize, but facial twist approaches normal. Technique improvement should focus on residual coronal asymmetry present at opisthion. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.