Application of micro-computed tomographic scanning to characterize patterns of murine cranial suture fusion.

BACKGROUND: In the murine model of suture fusion, it is widely accepted that the posterior frontal suture progresses from a state of patency on day 25 through complete fusion by day 45. The present study was performed to evaluate the process of normal posterior frontal suture fusion and to quantitate patterns of suture morphology in prefusion and postfusion mouse calvariae. METHODS: The calvariae of mice euthanized on day 25 (n = 7) and day 45 (n = 7) of postnatal life were analyzed by micro-computed tomography with 21-mm sections from each posterior frontal suture and analyzed by a nonblinded investigator for patency or fusion in the ectocranial, central, and endocranial segments. RESULTS: Both the ectocranial and central surface of the posterior frontal suture demonstrate a statistically significant difference in percentage fusion on day 25 versus day 45 of postnatal life. When compiled as a single suture complex, patterns of patency and fusion across the three defined levels showed a distinct trend toward patency at 25 days (19.8 ± 4.4 percent) and fusion at 45 days (48.6 ± 6.7 percent), but this relationship was not absolute. CONCLUSIONS: Although it has previously been thought that the posterior frontal suture in the mouse is fully patent on day 25 and fused on day 45, micro-computed tomographic analysis of the suture suggests otherwise. Accurate characterization of the timing and pattern of fusion in the mouse posterior frontal suture is an essential component to our understanding of the murine model, which serves as a widely studied analogue for suture fusion in humans.

Refinements of tissue expansion for pediatric forehead reconstruction: a 13-year experience.

BACKGROUND: Reconstruction of the forehead in children when 25 percent or more of the forehead is involved presents a complex reconstructive challenge because of the confluence of highly visible aesthetic units. The present study was performed to develop an algorithm for lesions involving 25 percent or more of the forehead. METHODS: A 13-year retrospective review was performed of all pediatric patients who completed reconstruction for lesions involving at least 25 percent of the forehead by a single surgeon (A.K.G.). All lesions were classified on the basis of percentage of forehead involved and involvement of adjacent subunits. RESULTS: Twenty patients completed reconstruction. The median number of surgical procedures required was six (range, two to 11), with a median of three (range, one to four) expansion procedures. Simultaneous expanders were placed in the scalp (16 patients) and cheek (eight patients). Five patients underwent correction of eyebrow ptosis at a final procedure. Reconstruction involved 25 to 70 percent of the forehead in 19 patients, 17 of whom were reconstructed with serial forehead expansion and advancement flaps. One patient with a pigmented nevus occupying more than 75 percent of the forehead received an expanded full-thickness skin graft from the lower abdomen. For all groups, the entire extent of the visible lesion was excised and complete skin coverage achieved. CONCLUSIONS: Reconstruction of 25 to 70 percent or more of the forehead in children is best accomplished using tissue expansion and direct advancement of adjacent tissues. Simultaneous expansion should be performed in the cheek and scalp if indicated. Brow ptosis should be addressed with each advancement. Lesions greater than 70 percent of the forehead are best accomplished with distant tissues.

A reinvestigation of murine cranial suture biology: microcomputed tomography versus histologic technique.

BACKGROUND: Histology remains the standard form to analyze cranial suture in murine models, but this technique provides only limited "snapshots" of the entire suture and requires animal euthanasia with tissue destruction. Because of the bone complex microarchitecture, better methods are required to study the behavior of the cranial suture and its surrounding environment. The authors compared microcomputed tomography and histology as techniques to evaluate murine cranial sutures. METHODS: A total of 360 microcomputed tomography images and 160 to 170 histologic sections were processed from a mouse at postnatal days 22 and 45, respectively. After euthanasia, the posterior frontal and sagittal sutures were imaged with a microcomputed tomography system and subsequently processed for histologic analysis. Quantitative analysis of two-dimensional images was performed to determine the percentage of bone in a 1-mm sample. RESULTS: Quantitative analysis of the percentage of bone within the sutures showed identical patterns by microcomputed tomography and histology techniques. Both methods demonstrated the posterior frontal suture to have heavier fusion patterns in the anterior and endocranial portions, with variable skip areas of complete patency on the endocranial surface, ectocranial surface, or both at day 45. CONCLUSIONS: Cranial suture fusion in the murine model is not an "all-or-none" phenomenon. The posterior frontal suture, previously thought to be completely fused on day 45 by histological analysis, showed variable fusion along the length of the suture by both methods. Quantitative assessment of the percentage of bone within the posterior frontal and sagittal sutures and morphologic assessment of these sutures demonstrated similar findings by both methods. Whereas thorough histologic evaluation of an entire suture would be extremely labor intensive and impractical, these findings help to validate microcomputed tomography as a rapid and reliable method of examining the entire suture in murine models.

Recurrent ectopic calcification involving the maxillofacial skeleton: A potential harbinger of Albright's osteodystrophy.

We present a case of osteoma cutis as the initial presenting sign of Albright's osteodystrophy. Albright's osteodystrophy represents a challenge in both diagnosis and treatment because the phenotype manifests as a broad spectrum of biochemical and physical findings. The syndrome may be overlooked, particularly in the early phases when serum calcium and phosphorous levels may be normal. Although surgery is the treatment of osteoma cutis, recurrence is common, creating frustration for the patient's family and the surgeon. In the present case, a girl 4 months and 2 years of age presented with refractory ectopic calcification emanating from the maxilla and demonstrated repeated recurrence after surgical resection. This ectopic calcification was not adequately controlled until Albright's osteodystrophy was properly diagnosed and treated. A differential diagnosis and surgical approach to deal with recurrent ectopic calcification of the facial skeleton is outlined.

Intraneural ganglion of the suprascapular nerve: case report.

UNLABELLED: We present a case of multicystic ganglion of the suprascapular nerve in an 18-year-old man. Pain and shoulder weakness were present and examination showed weakness and atrophy of the supraspinatus and infraspinatus muscles. Electromyography showed severe denervation of the infraspinatus and supraspinatus muscles. At surgery a multicystic lesion of the suprascapular nerve extending approximately 5.7 cm from its origin was resected and reconstructed by sural nerve grafting. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level V.

Intraneural perineurioma of the radial nerve in a child.

An intraneural perineurioma is an uncommon solitary neoplasm of major nerve trunks composed of perineurial cells from the peripheral nerve sheath. The typical course of intraneural perineurioma is indolent, with gradual-onset motor loss and presentation for evaluation months to years after onset of symptoms. We report a 9-year-old girl with an intraneural perineurioma of the radial nerve. Diagnosis was confirmed by histology and immunohistochemistry. Resection and nerve graft reconstruction were performed to prevent progression of motor compromise and to allow recovery of motor function. An algorithm for the management of focal intraneural tumors is shown.