Posterior Calvarium Research Articles

Virtual Planning for Exchange Cranioplasty in Cranial Vault Remodeling

The use of virtual surgical planning and computer-aided design/computer-aided manufacturing has gained popularity in the surgical correction of craniosynostosis. This study expands the use of virtual surgical planning and computer-aided design/computer-aided manufacturing in cranial vault reconstruction by using these methods to reconstruct the anterior vault using a single endocortically-plated unit constructed from the posterior calvarium. This technique was designed to reduce the risk of undesirable contour deformities that can occur when multiple bone grafts are used to reconstruct the anterior vault and fronto-orbital rim. Six patients were included in this study, all of which had nonsyndromic craniosynostosis. Excellent aesthetic outcomes were obtained in all patients, without complication. Additionally, the placement of a single reconstructive unit constructed from the posterior calvarium was efficient, aesthetically pleasing, and minimized postoperative contour deformities secondary to bone gaps, resorption, and often palpable resorbable plates.

Serial Posterior Cranial Vault Distraction for the Treatment of Complex Craniosynostosis.

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

Dietary material properties shape cranial suture morphology in the mouse calvarium.

Cranial sutures are fibrous connective tissue articulations found between intramembranous bones of the vertebrate cranium. Growth and remodeling of these tissues is partially regulated by biomechanical loading patterns that include stresses related to chewing. Advances in oral processing structure and function of the cranium that enabled mammalian-style chewing is commonly tied to the origins and evolution of this group. To what degree masticatory overuse or underuse shapes the complexity and ossification around these articulations can be predicted based on prior experimental and comparative work. Here, we report on a mouse model system that has been used to experimentally manipulate dietary material properties in order to investigate cranial suture morphology. Experimental groups were fed diets of contrasting material properties. A masticatory overuse group was fed pelleted rodent chow, nuts with shells, and given access to cotton bedding squares. An underuse group was deprived of cotton bedding as well as diverse textured food, and instead received gelatinized food continuously. Animals were raised from weaning to adulthood on these diets, and sagittal, coronal and lambdoid suture morphology was compared between groups. Predicted intergroup variation was observed in mandibular corpus size and calvarial suture morphology, suggesting that masticatory overuse is associated with jaw and suture growth. The anterior region of the sagittal suture where it intersects with the coronal suture (bregma) showed no effect from the experiment. The posterior sagittal suture where it intersects with the lambdoid sutures (lambda) was more complex in the overuse group. In other words, the posterior calvarium was responsive to dietary material property demands while the anterior calvarium was not. This probably resulted from the different strain magnitudes and/or strain frequencies that occurred during overuse diets with diverse material properties as compared with underuse diets deprived of such enrichment. This work highlights the contrasting pattern of the sutural response to loading differences within the calvarium as a result of diet.

Oligometastatic Prostate Cancer: Molecular Imaging and Clinical Management Implications in the Era of Precision Oncology.

1338 Objectives: Differentiated thyroid cancer (DTC) patients with elevated or rising serum thyroglobulin (Tg) levels and multiple other negative conventional imaging studies represent a clinically difficult group of patients. 99m Tc-sestamibi is a non-conventional imaging study for DTC that was used in the 1980s-1990s to help evaluate DTC patients before being replaced with 18F-FDG. However, 18F-FDG PET scans may also be negative in these patients. This is a preliminary analysis of our study to evaluate the diagnostic use of 99mTc-sestamibi scans to identify the source of elevated or rising Tgs in patients with negative conventional imaging including negative 18F-FDG PET scans. Methods This prospective study included DTC patients who were at least 18 years old, had at least one prior 131I therapy, and had elevated Tg>5 ng/ml or positive anti-Tg antibodies (TgAb). In addition, all of the following imaging studies must have been clinically reported as negative for recurrence or metastasis within the last 12 months: neck ultrasound, diagnostic radioiodine scan, chest x-ray, CT of the chest/abdomen with/without contrast, and 18F-FDG PET/CT. If other imaging studies were performed, such as bone scans or brain imaging, these must also have been read as negative. This study was approved by the IRB at MedStar Health and all participants signed informed consent. Participants were injected with 925 MBq (25 mCi) of 99mTc-sestamibi intravenously and whole body images were acquired after ~1h with acquisition speed 4cm/min with parallel-hole low-energy collimator. Extra spot view, pinhole view, or SPECT/CT images were performed when necessary. Two blinded nuclear medicine physicians independently interpreted the 99mTc-sestamibi images, and graded each foci 1-5 (1 = definite physiological uptake or artifact; 2 = most likely physiological uptake or artifact; 3 = indeterminate; 4 = most likely recurrence or metastasis; 5 = definite recurrence or metastasis). Discordant findings were resolved by consensus. Foci graded 3-5 were categorized as positive result and was followed-up for confirmation. Results A total of four patients completed the sestamibi scan to date. One out of four patients (Patient1) was positive on the sestamibi scan for distant metastasis. In Patient 1, the sestamibi whole-body posterior image demonstrated abnormal focal uptake in the right posterior calvarium and corresponding to an occipital lytic bone lesion on the SPECT/CT (Figure 1). The patient underwent surgical resection of the skull metastasis, and pathology confirmed metastatic thyroid cancer. Five months post-surgery the suppressed Tg was markedly reduced and stable at ~3.2ng/ml. Table 1 shows the sestamibi scan results, subsequent management and follow-up. With confirmation of the location of the metastatic foci in Patient 1, the two negative 18F-FDG PET/CT that were previously performed one year apart were reviewed again. The radiology reports did not document interpretation of the low-dose localization CT. In retrospect, the lytic skull metastasis was visible on both of the head CT, but could have been easily missed on the PET due to the normal intensive brain 18F-FDG activity. Conclusions In this preliminary analysis, 99mTc-sestamibi was able to identify the source of elevated Tg levels in one out of four DTC patients with biochemical recurrence and negative conventional imaging studies. 99mTc-sestamibi may have a role in thyroid cancer localization when physical exam, neck ultrasound, radioiodine scan, chest/abdomen CT, and 18F-FDG PET/CT could not identify. Additional patients are being recruited. Research Support We are grateful for the generous donations from our patients.

Early Posterior Vault Distraction Osteogenesis for the Treatment of Syndromic Craniosynostosis.

Posterior cranial vault distraction (PCVD) has become an important modality in the management of complex craniosynostosis to increase intracranial volume and improve the cranial vault appearance. This technique can safely be performed as early as 3 months of age for the initial management of patients with complex craniosynostosis. A retrospective review was performed of all the patients with syndromic, multiple-suture synostosis treated with PCVD at Primary Children's Hospital in Salt Lake City, Utah, between 2012 and 2014. During this time period, a total of nine children with an average corrected age of 21.4 weeks were treated. Demographics, intraoperative data, and postoperative distraction data were collected. Occipital frontal head circumferences (OFCs) were recorded pre- and postdistraction, and at 3- and 6-month follow-up examinations. All patients had a substantial increase in head circumference with subjective improvement of the posterior calvarium shape. The average increase in OFC from preoperative to postdistraction was 4.9 cm. Only two significant postoperative complications were encountered, one hardware infection and one cerebrospinal fluid leak. PCVD is an effective procedure in the management of complex craniosynostosis and can be safely initiated very early in life.

Results of posterior cranial vault remodeling for plagiocephaly and brachycephaly by the meander technique.

Several techniques to remodel the posterior calvarium in order to increase intracranial volume (ICV) and to improve cosmetic appearance are reported. This study presents the results of meander technique in patients with brachycephaly and posterior plagiocephaly. During December 2011 and July 2013, a total of 12 children (median age: 15 months) underwent posterior cranial vault remodeling by the meander technique (brachycephaly, n = 6; posterior plagiocephaly, n = 6). The available pre- and postoperative MRIs were assessed with regard to ICV, cranial index (CI) and asymmetry index (AI) as well as the position of the cerebellar tonsils. No intra- or postoperative complications were observed. Blood transfusions were necessary in nine of 12 patients. A significant increase of the ICV from 1,178.4 ± 134.5 to 1,293.0 ± 137.5 cm(3) (p < 0.05) is demonstrated. In the patients with brachycephaly the CI was significantly improved from 0.97 ± 0.12 to 0.89 ± 0.12 postoperatively (p < 0.05). The AI in patients with posterior plagiocephaly was significantly ameliorated from 0.83 ± 0.04 to 0.92 ± 0.02 postoperatively (p < 0.05). There was a significant effect on cerebellar tonsil position in relation to foramen magnum level for patients with brachycephaly (right tonsil: 11.9 ± 9.2 to 7.0 ± 9.1 mm, p < 0.05; left: 10.8 ± 9.5 to 9.7 ± 10.6 mm; p < 0.05) as well as in posterior plagiocephaly for the ipsilateral tonsil (3.2 ± 3.5 to 1.6 ± 3.5 mm; p < 0.01). The presented surgical technique is considered to be safe. The technique is capable to significantly increase ICV and improve cosmetic appearance of the remodeled calvarium. Further evidence that posterior cranial vault remodeling influences the position of the cerebellar tonsils is added by the results of the study.

Posterior calvarial distraction in craniosynostosis – An evolving technique

BackgroundPosterior advancement of the occiput is an established surgical option for the treatment of raised intracranial pressure (ICP) secondary to craniocerebral disproportion in syndromic craniosynostoses. Distraction osteogenesis has gained popularity in a variety of craniofacial procedures to achieve greater advancement in the anterior craniofacial skeleton, but has only relatively recently been used in the posterior calvarium. We report the Oxford Craniofacial Unit’s experience of using distraction techniques to expand the occiput. MethodsWe preformed a retrospective casenote review of all patients with syndromic craniosynostoses who underwent posterior distraction at our centre from 2007 to 2010, as identified by the Oxford Craniofacial Database. ResultsTen syndromic patients underwent posterior distraction (mean age of 18.1months). Successful calvarial expansion (mean advancement of 19.7mm) was achieved in all patients clinically and radiologically. There were 6 minor and 1 major complications. ConclusionsPosterior distraction was successfully performed in 10 patients including babies as young as 3months of age. It achieved a reduction in turricephaly, an improvement in the cephalic index, and a resolution of raised ICP. We have customised our surgical technique to address individual patient needs. The use of distraction techniques in the occiput appears to increase the reliability of expansion in this region.

Roentgenographic cranial-base and calvarial measurements of north Indian children from birth to two years of age.

In order to establish norms for dimensions of the skull in North Indian children, lateral skull films of 166 apparently healthy, normocephalic children between birth and two years of age were studied. Using bony reference points, measurements were made of cranial-base length and calvarial height. It appears that there is definite proportionality between growth of ventral and posterior cranial-base, calvarium and ventral base, and anterior and posterior calvarium, at all ages and for both sexes. Deviation in these proportions may suggest abnormality in a corresponding area of the cranium.