Negative pressure therapy for closed spine incisions: a pilot study.

UNLABELLED: Negative pressure therapy (NPT), used on open wounds or postoperative infections, has not been evaluated on closed spinal incisions. This was analyzed after 3 days and 5 days of NPT application using biomechanics and histology in a porcine model. METHODS: In 8 mature miniature pigs, 2 end-to-end midline spine incisions were closed in a standard fashion. Negative pressure (Prevena™ Incision Management System, KCI, San Antonio,TX) was applied to one incision (NPT group) while standard dry dressings were used on the other (control group). After 3 days or 5 days, all incisions underwent biomechanical (eg, failure load, failure energy, and stress), histological, and scar scale evaluation. ANALYSIS: ANOVAs compared the groups (3-day vs 5-day, NPT vs control, P < 0.05). Negative pressure therapy demonstrated a significantly improved scar scale height grade than the control (P = 0.026). Failure load (4.9 ± 4.0 vs 16.5 ± 14.6 N), energy absorbed (8.0 ± 9.0 vs. 26.9 ± 23.0 mJ), and ultimate stress (62 ± 53 vs. 204 ± 118 N/mm2) were lower in the control group. Histological analysis revealed no differences in incision scar width. CONCLUSION: Negative pressure therapy application on closed incisions presented a trend toward improved early healing strength, and in significantly improved incision appearance. Clinically, NPT may improve incision integrity, minimizing the risk of dehiscence or subsequent infection. Patients at high risk of postoperative incision site complications may benefit from primary application of NPT.

A morphometric analysis of the infant calvarium and dura.

Literature addressing the anatomic development of the dura and calvarium during childhood is limited. Nevertheless, histological features of a subdural neomembrane (NM), including its thickness and vascularity, developing in response to an acute subdural hematoma (SDH) have been compared to the dura of adults to estimate when an injury occurred. Therefore, we measured the morphometric growth of the calvarium and dura and the vascular density within the dura during infancy. The mean thicknesses of the calvarium and dura as a function of occipitofrontal circumference (OFC), as well as the mean number of vessels per 25 × field, were determined from the right parasagittal midparietal bone lateral to the sagittal suture of 128 infants without a history of head trauma. Our results showed that as OFC increased, the mean thicknesses of the calvarium and dura increased while the vascular density within the dura decreased. Our morphometric data may assist in the interpretation of subdural NM occurring during infancy. We recommend future investigations to confirm and extend our present data, especially by evaluating cases during later infancy and beyond as well as by sampling other anatomic sites from the calvarium. We also recommend morphometric evaluation of subdural NM associated with SDH in infancy and childhood.

Spinal growth modulation with an anterolateral flexible tether in an immature bovine model: disc health and motion preservation.

STUDY DESIGN: An immature bovine model was used to evaluate multilevel anterolateral flexible tethering in a growing spine. OBJECTIVE: To evaluate radiographic, biochemical, histologic, and biomechanical results of tethered spinal growth. SUMMARY OF BACKGROUND DATA: An anterolateral flexible tether has been shown to create a kyphotic and scoliotic spinal deformity in calves. Subsequent disc health and spinal motion has not been analyzed. METHODS: Four consecutive thoracic vertebral bodies (T6-T9) were instrumented anteriorly in 36 1-month-old calves. Seventeen animals (Tether Group) were instrumented with a vertebral staple-two screw construct connected by 2 flexible stainless steel cables. Nineteen animals (Control Group) were instrumented with 1 vertebral body screw with no connecting cable. After a 6-month survival period, the spines were harvest en-bloc and underwent radiographic, computed tomography, biochemical, histologic, and biomechanical analysis. RESULTS: On average, 37.6 degrees +/- 10.6 degrees of coronal and 18.0 degrees +/- 9.9 degrees of sagittal deformity was created in the Tether Group, with significant vertebral wedging toward the tether (P < 0.001). Disc thickness decreased significantly in the Tether Group (P < 0.001), however, disc wedging was not observed. There was no change in gross morphologic disc health or disc water content (P = 0.73). However, proteoglycan synthesis was significantly greater in the tethered discs compared with controls (P < 0.001), and collagen type distribution was different with a trend toward increased type II collagen present on the tethered side of the disc (P = 0.09). Tethers significantly increased spinal stiffness in lateral bending and in flexion/extension (P < 0.05) without affecting torsional stiffness, however, after tether removal range of motion returned to control values. CONCLUSION: Tethering resulted in vertebral wedging while maintaining spinal flexibility. Although changes in proteoglycan synthesis, collagen type distribution, and disc thickness were observed, the tethered discs had similar water content to control discs and did not demonstrate gross morphologic signs of degeneration. Growth modulation is an attractive treatment option for growing patients with scoliosis, avoiding multilevel fusions or brace wear. Strategies for fusionless scoliosis correction should preserve disc health, as adolescent patients will rely on these discs for decades after treatment.

Congenital cerebellar malignant rhabdoid tumor in an infant with junctional epidermolysis bullosa.

Epidermolysis bullosa (EB), a hereditary blistering condition of the skin, is divided into simplex, hemidesmosomal, junctional, and dystrophic types. It may be complicated by the development of squamous cell carcinoma of the skin, but other neoplasms, especially those separate from involved skin, are distinctly rare. We report a male infant with junctional EB who died of Pseudomonas sepsis and was found at autopsy to have a clinically unrecognized cerebellar malignant rhabdoid tumor (MRT). This is the first reported case of an infant with EB and a coincident extracutaneous neoplasm. It is also the first known case of EB associated with a pathologically confirmed malignant brain tumor. Cytogenetic results from the infant and his tumor and both of his parents suggest the infant's EB and MRT were not genetically linked.

Nephrogenic systemic fibrosis with multiorgan involvement in a teenage male after lymphoma, Ewing's sarcoma, end-stage renal disease, and hemodialysis.

Nephrogenic systemic fibrosis (NSF) is a rare condition that always occurs after acute or chronic renal failure with or without dialysis. The vast majority of cases in the literature are adults, and postmortem findings have been reported in only 5 cases. We report a 15-year-old male who developed NSF with multiorgan involvement after successful treatment of renal lymphoma and a subsequent sacral Ewing's sarcoma, and end-stage renal disease treated with hemodialysis. At autopsy, he was found to have diffuse dural osseous metaplasia, transmural bronchiolar fibrosis, diaphragmatic central tendon fibrosis, and fibrous plaques of the mitral valve. These previously unreported findings expand the spectrum of multiorgan involvement in NSF providing additional evidence that it is an emerging systemic disorder.

Thoracic vertebral screw impingement on the aorta in an in vivo bovine model.

STUDY DESIGN: A bovine model was used to evaluate the effects of thoracic vertebral screw impingement of the aorta. OBJECTIVES: To evaluate the histologic and biomechanical changes in aortic wall tissue that was severely impinged by abutting instrumentation. SUMMARY OF BACKGROUND DATA: Case reports of vascular injury associated with spinal instrumentation generally describe intraoperative injury; some report delayed presentation of large vessel damage. Risks associated with placing instrumentation adjacent to large vessels are largely unknown. METHODS: Six 1-month-old calves underwent left-sided thoracotomies, exposing the anterior thoracic spine and aorta. With the heads removed, screws were inserted in reverse fashion into T6 through T11, leaving the screw tips 1 cm proud and abutting the aorta. After 3, 6, or 12 months (2 calves each), the spines were resected with the adjacent aorta and underwent radiographic, histologic, and biomechanical testing. RESULTS: Computed tomography revealed varying degrees of vessel impingement. Although there were no frank ruptures, 96% of aortic specimens showed histopathologic changes, including 52% with wall thinning; 43% were no longer impinged, yet 60% of these had increased collagen (scar). Biomechanical testing of screw-impinged aortas demonstrated a lower failure stress (1.2 +/- 0.5 N/mm vs. 1.8 +/- 0.4 N/mm, P = 0.016) but no difference in failure strain (42 +/- 9% vs. 32 +/- 10%, P = 0.06) than controls. CONCLUSIONS: Major impingement of vertebral screws on the aorta caused acute and chronic histopathologic and biomechanical changes in the vessel wall. This model represents a severe form of vessel penetration by a screw that confirms such a "worst case" scenario results in marked compromise of the vessel wall integrity. The sequelae of less severe impingement are unknown.

Autoinfarcted wandering spleen and fatal pneumococcal sepsis in an infant.

A wandering or ectopic spleen, a rare congenital condition caused by improper fixation of the ligamentous attachments, was identified during a postmortem examination of a 10-month-old female who had died of Streptococcus pneumoniae sepsis. The wandering spleen was autoinfarcted and adherent to the left hepatic lobe, with resultant functional hyposplenism.

Characterization of a white bass (Morone chrysops) embryonic cell line with epithelial features.

The genus Morone is an important one for U.S. aquaculture, but there has been no available cell line from this genus. We report here a cell line (the WBE line) derived from white bass embryos that has been grown for more than 80 passages over 21 mo in Dulbecco modified Eagle medium supplemented with fetal bovine serum. The WBE line showed epithelial features with positive immunohistochemical staining for cytokeratin and intercellular junctions when observed by electron microscopy. The doubling time, transformation characteristics, response to cryopreservation, and karyotype were determined. The WBE line was also tested by polymerase chain reaction to verify the species of origin and to screen for mycoplasma infection. This epithelial cell line may prove useful for the study of host-pathogen interactions that occur at the epithelial surface in this commercially important fish species.