Use of Temporal Morphomic Indices as a Clinically Important Variable in the Diagnosis of Nonsyndromic Craniosynostosis

Late Deformity Following Fronto-Orbital Reconstructive Surgery for Metopic Synostosis: The Role of Temporalis Muscle

ABSTRACT

Theories for late-developing deformity (LDD) following fronto-orbital reconstructive surgery (FOR) for metopic synostosis (MS) must explain both its delayed onset and its physical characteristics. This study examined whether FOR-related interference with the normal childhood expansion of temporalis is responsible for its soft tissue component.Three-dimensional reformats of preoperative and postoperative computed tomography scans of MS patients were reviewed. Measurements of vertical and horizontal reach of temporalis against those of the underlying skull (to allow for normal skull growth) were compared with normal subjects. The thickness of temporalis and the development of the temporal crests were also assessed.Mean age at FOR was 17.1 months; interval between surgery and first report of LDD 4.7 years; mean age at computed tomography scan for post-FOR LDD patients 8.8 years. There was a significant difference between vertical and horizontal reach of temporalis in pre-FOR MS patients compared to normal subjects (P < 0.0017 and P < 0.05, respectively). The vertical age-related reach of temporalis in post-FOR patients after allowing for underlying skull growth was significantly reduced (P = 0.0045) compared to normal subjects but not its horizontal reach (P = 0.25). Temporal crests in LDD patients were absent or aberrantly formed while muscle thickness was similar to normal subjects at the 2 levels measured.This study supports the theory that failure of the normal childhood expansion of temporalis is responsible for the soft tissue element of LDD, accounting for both its delayed onset and physical characteristics. Aberrant temporal crest development suggests FOR-related damage as the probable cause.

Debunking a Surgical Myth: Do Not Touch the Temporalis

BACKGROUND

A longstanding dictum exists to avoid surgical manipulation of the temporalis muscle out of concern for an exceedingly high rate of muscle atrophy and recurrent temporal hollowing. The authors challenge this surgical myth, considering such advice to be erroneous. The authors hypothesize that elevation of the temporalis muscle, if performed using standard muscle flap principles, will demonstrate excellent results.

METHODS

To assess temporalis response to surgical manipulation, the authors reviewed patients who underwent calvarial vault remodeling by the senior author for craniosynostosis between 1988 and 2011. Nonsyndromic patients with single-suture synostosis and 5 years of follow-up were eligible for inclusion. The medical record was used to measure rates of reoperation, recurrent temporal hollowing, and persistent temporalis overcorrection.

RESULTS

Of the cohort reviewed, 196 patients met inclusion criteria. Ten patients (5.1%) exhibited recurrent bitemporal constriction. One patient (0.5%) underwent a revision temporalis turnover flap, and 2 patients (1.0%) underwent soft tissue augmentation. The overall reoperation rate was 1.5%. Temporalis overcorrection, in an attempt to prophylactically rectify the expected atrophy after temporalis manipulation, persisted in 11 patients (5.6%). Three of these patients required treatment with steroid injections, Botox injections, or operative muscle debulking. The overall reoperation rate for temporalis overcorrection was 1.5%.

CONCLUSIONS

The authors' low reoperation rates for recurrent deformity, in combination with persistent temporalis overcorrection in 5.6% of patients, should dispel the myth that manipulation of the temporalis invariably results in atrophy. The muscle may be surgically manipulated, as long as plastic surgery principles are followed.

Early Surgical Treatment in Anterior Synostotic Plagiocephaly: Is This the Best Choice?

At the end of craniofacial growth, in anterior synostotic plagiocephaly, some aesthetical deficiencies may still be evident. This can depend on an inadequate initial correction or on altered postoperative growth or even on the combination of the 2 factors.Aesthetic alterations can result from various factors that could potentially affect the skeleton, the skin, subcutaneous, and muscular tissues.The pathological changes in the cutaneous and subcutaneous tissues are greater in patients who have undergone multiple surgical treatments of the frontoorbital area. The aim of this observational cohort study is to assess the residual aesthetic and functional impairment at the end of skeletal growth, in patients affected by anterior synostotic plagiocephaly who have undergone surgery at an early age. The purpose is to investigate whether early surgery can still be considered unavoidable in patients with this malformation.Between July 2012 and February 2015, patient's data were retrieved from our archives among the patients referred to our department from 2003 to 2012 for Anterior Synostotic Plagiocephaly at an early age.The authors studied this patient with CT scans and photographic documentation. On CT scans, the authors have assessed skeletal alterations, soft tissues alterations, and muscular tissue alterations. With photographic documentation, the authors have studied the perception of the malformation among external subjects.From this study it was possible to demonstrate that is many esthetical alterations are to still to be found in patients treated with an early surgical approach; for this reason in children without early complications, the authors suggest that surgical treatment should be delayed after the end of craniofacial growth.

Personalized medicine: Enhancing our understanding of pediatric growth with analytic morphomics

BACKGROUND/PURPOSE

Analytic morphomics is being used to identify 3-D biologic measures with superior clinical utility and risk stratification over traditional factors such as age, height, and weight. The purpose of this study is to define age and gender specific Pediatric Reference Analytic Morphomics Population (PRAMP™) growth charts.

METHODS

This retrospective study population contains 2591 individual CT scans of a normative reference population of males and females (1-20years old). Growth curves were constructed at the 5th, 25th, 50th, 75th, and 95th quantiles for morphomic variables, including psoas muscle area, trabecular bone density, and visceral fat area by age and gender.

RESULTS

Total psoas muscle area increases over time until late adolescence. Trabecular bone density remains stable until adolescence, decreases during adolescence, and increases in young adulthood. Visceral fat area increases over time with greater variation between the 5th and 95th percentile with increasing age.

CONCLUSIONS

The PRAMP™ data have been used to construct age- and sex-specific reference growth curves. This may be used to better define "abnormal" in efforts to create unique risk-categorization algorithms specific to particular clinical and global health investigations.

LEVEL OF EVIDENCE

Level II.

Postoperative temporal hollowing: Is there a surgical approach that prevents this complication? A systematic review and anatomic illustration

BACKGROUND

Temporal hollowing is a common complication following surgical dissection in the temporal region. Our objectives were to: (1) review and clarify the temporal soft tissue relationships - supplemented by cadaveric dissection - to better understand surgical approach variations and elucidate potential etiologies of postoperative hollowing; (2) identify if there is any evidence to support a surgical approach that prevents hollowing through a systematic review.

METHODS

Cadaveric dissection was performed on six hemi-heads. A systematic review of the literature was undertaken to identify surgical approaches with a decreased risk of postoperative hollowing.

RESULTS

A total of 1212 articles were reviewed; 19 of these met final inclusion criteria. Level I and II evidence supports against the use of a dissection plane beneath the superficial layer of the deep temporal fascia or through the intermediate temporal fat pad. Level II evidence supports preservation of the temporalis muscle origin - no evidence is available to support other temporalis resuspension techniques. For intracranial exposure, refraining from temporal fat pad dissection (Level I Evidence) and use of decreased access approaches such as the minipterional craniotomy (Level I Evidence) appear to minimize temporal soft tissue atrophy.

CONCLUSIONS

This study highlights the significance of preservation of the temporal soft tissue components to prevent hollowing. Preserving the temporalis origin and avoiding dissection between the leaflets of the deep temporal fascia or through the intermediate temporal fat pad appear to minimize this complication.

The metopic index: an anthropometric index for the quantitative assessment of trigonocephaly from metopic synostosis

OBJECTIVE Because the metopic suture normally fuses during infancy, there are varying degrees of severity in head shape abnormalities associated with premature fusion. A method for the objective and reproducible assessment of metopic synostosis is needed to guide management, as current methods are limited by their reliance on aesthetic markers. The object of this study was to describe the metopic index (MI), a simple anthropometric cranial measurement. The measurements can be obtained from CT scans and, more importantly, from palpable cranial landmarks, and the index provides a rapid tool for evaluating patients in both pre- and postoperative settings. METHODS High-resolution head CT scans obtained in 69 patients (age range 0-24 months) diagnosed with metopic craniosynostosis were retrospectively reviewed. Preoperative 3D reconstructions were available in 15 cases, and these were compared with 3D reconstructions of 324 CT scans obtained in a control group of 316 infants (age range 0-24 months) who did not have any condition that might affect head size or shape and also in a subset of this group, comprising 112 patients precisely matched to the craniosynostosis patients with respect to age and sex. Postoperative scans were available and reviewed in 9 of the craniosynostosis patients at a mean time of 7.1 months after surgical repair. 3D reconstructions of these scans were matched with controls based upon age and sex. RESULTS The mean preoperative MI for patients with trigonocephaly was 0.48 (SD 0.05), significantly lower than the mean values of 0.57 (SD 0.04) calculated on the basis of all 324 scans obtained in controls (p < 0.001) and 0.58 (SD 0.04) for the subset of 112 age- and sex-matched controls (p < 0.001). For 7 patients with both pre- and postoperative CT scans available for evaluation, the mean postoperative MI was 0.55 (SD 0.03), significantly greater than their preoperative MIs (mean 0.48 [SD 0.04], p = 0.001) and comparable to the mean MI of the controls (p = 0.30). In 4 patients, clinically obtained postoperative MIs by caliper measurement were comparable to measurements derived from CT (p = 0.141). CONCLUSIONS The MI is a useful measurement of the severity of trigonocephaly in patients with metopic synostosis. This simple quantitative assessment can potentially be used in the clinical setting to guide preoperative evaluation, surgical repair, and postoperative degree of correction.

Early Development of the Mouse Morphome

INTRODUCTION

Analytical morphomics focuses on extracting objective and quantifiable data from clinical computed tomography (CT) scans to measure patients' frailty. Studies are currently retrospective in nature; therefore, it would be beneficial to develop animal models for well-controlled, prospective studies. The aim of this study is to develop an in vivo microCT protocol for the longitudinal acquisition of whole-body images suitable for morphomic analyses of bone.

METHODS

The authors performed phantom studies on 2 microCT systems (Inveon and CT120) to study tissue radiodensity and further characterize system performance for collecting animal data. The authors also describe their design of a phantom-immobilization device using phantoms and an ovariectomized (OVX) mouse.

RESULTS

The authors discovered increased consistency along the z-axis for scans acquired on the Inveon compared with CT120, and calibration by individual slice reduces variability. Objects in the field of view had more impact on measurement acquired using the CT120 compared with the Inveon. The authors also found that using the middle 80% of slices for data analysis further decreased variability, on both systems. Moreover, bone-mineral-density calibration using the QCT Pro Mini phantom improved bone-mineral-density estimates across energy spectra, which helped confirm our technique. Comparison of weekly body weights and terminal uterine mass between sham and OVX groups validated our model.

DISCUSSION

The authors present a refined microCT protocol to collect reliable and objective data. This data will be used to establish a platform for research animal morphomics that can be used to test hypotheses developed from clinical human morphomics.

Facial changes after early treatment of unilateral coronal synostosis question the necessity of primary nasal osteotomy

BACKGROUND

The premature fusion of unilateral coronal suture can cause a significant asymmetry of the craniofacial skeleton, with an oblique deviation of the cranial base that negatively impacts soft tissue facial symmetry. The purpose of this study was to assess facial symmetry obtained in patients with unilateral coronal synostosis (UCS) surgically treated by 2 different techniques. We hypothesized that nasal deviation should not be addressed in a primary surgical correction of UCS.

METHODS

Consecutive UCS patients were enrolled in a prospective study and randomly divided into 2 groups. In group 1, the patients underwent total frontal reconstruction and transferring of onlay bone grafts to the recessive superior orbital rim (n = 7), and in group 2, the patients underwent total frontal reconstruction and unilateral fronto-orbital advancement (n = 5). Computerized photogrammetric analysis measured vertical and horizontal axis of the nose and the orbital globe in the preoperative and postoperative periods. Intragroup and intergroup comparisons were performed.

RESULTS

Intragroup preoperative and postoperative comparisons showed a significant (all P < 0.05) reduction of the nasal axis and the orbital-globe axis in the postoperative period in the 2 groups. Intergroup comparisons showed no significant difference (all P > 0.05).

CONCLUSIONS

Facial symmetry was achieved in the patients with UCS who underwent surgery regardless of surgical approach evaluated here. Our data showed a significant improvement in nasal and orbital-globe deviation, leading us to question the necessity of primary nasal correction in these patients.