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Biomedical subjects

Jeffrey Weinzweig

Publications and source records attributed to Jeffrey Weinzweig.

12 recordsLinked to original sources
PubMed2006

The fetal cleft palate: IV. Midfacial growth and bony palatal development following in utero and neonatal repair of the congenital caprine model.

BACKGROUND: Midfacial hypoplasia and growth disturbances following cleft palate repair are well-known consequences of the maxillary scarring inherent with each repair technique. The present study investigated the influence of in utero palatoplasty, and cleft repair in 6-week-old goats, on midfacial growth and bony palatal development in the authors' congenital caprine cleft palate model in an effort to identify an inherent component of facial growth impairment associated with the cleft anomaly. METHODS: At 85 days' gestation, eight clefted fetuses underwent in utero cleft palate repair using a modified von Langenbeck technique; eight fetuses remained as unrepaired controls. At 6 weeks of age, eight goats underwent cleft palate repair using the same technique. All goats were euthanized at 6 months of age; dry skull measurements and cephalometric analyses were performed. RESULTS: Fetal Repairs: Both repaired and unrepaired clefted goats demonstrated significant evidence of maxillary hypoplasia compared with unclefted controls. Repaired goats showed a decrease of 15.7 percent in maxillary length, and unrepaired clefted goats showed a decrease of 18.0 percent in maxillary length, compared with unclefted controls. There was no significant difference in maxillary growth between the repaired and unrepaired clefted groups. Bony cleft width was reduced by 48 percent anteriorly and 60 percent posteriorly. Thirty-seven percent of repaired congenital clefts demonstrated partial bony fusion involving 10 to 70 percent of the palatal length. This was accompanied by an 8.8 percent decrease in maxillary width at the level of the third molar crown compared with unclefted controls and an 18.3 percent decrease in maxillary width compared with unrepaired clefted goats. Unrepaired clefted goats demonstrated neither a decrease in maxillary width nor any narrowing or fusion of the bony cleft. Newborn Repairs: Significant midfacial growth impairment was seen in animals that underwent cleft palate repair at 6 weeks of age compared with those repaired in utero and with unclefted controls. Repaired clefted goats demonstrated a significant decrease in maxillary length by 29.5 percent compared with unclefted controls and 16.4 percent compared with the group repaired in utero. Repaired goats also demonstrated a significant decrease in maxillary width in the transverse dimension at the level of the third molar. A decrease in maxillary width of 25.3 percent was seen compared with the unclefted controls and 18.1 percent compared with the fetal repairs. Bony cleft width was reduced by 32 percent anteriorly and 27 percent posteriorly following repair at 6 weeks of age. Although all goats demonstrated narrowing following repair, partial bony palatal fusion was not seen in this group. CONCLUSIONS: In utero cleft palate repair does not contribute to impairment of midfacial growth. The authors attribute this finding to the scarless nature of mucoperiosteal healing in the privileged fetal environment. However, the cleft palate anomaly does have an inherent component of facial dysmorphology that is evidenced as maxillary hypoplasia or retrusion in unrepaired clefted animals. Cleft repair in the newborn period, or thereafter, results in midfacial growth impairment in a manner similar to that seen clinically. The authors attribute this finding to the scarring that routinely accompanies conventional palatoplasty. The combination of the growth impairment inherent in the cleft anomaly and that attributable to postnatal repair scarring yields the midfacial retrusion commonly associated with cleft palate.

Animals↗
PubMed2006

Applicability of the nipple-areola complex-sparing mastectomy: a prediction model using mammography to estimate risk of nipple-areola complex involvement in breast cancer patients.

The purpose of this study was to develop a prediction model that can be used to identify breast cancer patients at lowest risk for neoplastic nipple-areola complex (NAC) involvement to offer total NAC-sparing mastectomy with immediate reconstruction. Medical records, pathology slides, and mammograms were reviewed for all breast cancer patients treated with total mastectomy at Rhode Island Hospital between 2000 and 2004. The distance between the nipple and the closest tumor margin was measured using mammography. NAC involvement was identified in 42% of the 31 study patients. Mammographic distance, pathologic stage, and tumor size were identified as independent predictors of malignant NAC involvement by multivariate analysis (rho < 0.05). Based on these predictors, a linear discriminant score, the NAC Involvement Score (NACIS), was computed to distinguish between the presence and absence of NAC involvement. For individual patients, positive NACIS values (> or = -0.3665) were associated with NAC involvement with a sensitivity of 92%, specificity of 77%, and negative predictive value of 93%. These preliminary findings indicate that the NACIS formula may be a useful clinical tool for selecting low-risk patients for total NAC-sparing mastectomy with immediate reconstruction.

Adult↗
PubMed2005

Designing a virtual reality model for aesthetic surgery.

BACKGROUND: Aesthetic surgery deals in large part with the manipulation of soft-tissue structures that are not amenable to visualization by standard technologies. As a result, accurate three-dimensional depictions of relevant surgical anatomy have yet to be developed. This study presents a method for the creation of detailed virtual reality models of anatomy relevant to aesthetic surgery. METHODS: Two-dimensional histologic sections of a cadaver from the National Library of Medicine's Visible Human Project were imported into Alias's Maya, a computer modeling and animation software package. These two-dimensional data were then "stacked" as a series of vertical planes. Relevant anatomy was outlined in cross-section on each two-dimensional section, and the resulting outlines were used to generate three-dimensional representations of the structures in Maya. RESULTS: A detailed and accurate three-dimensional model of the soft tissues germane to aesthetic surgery was created. This model is optimized for use in surgical animation and can be modified for use in surgical simulators currently being developed. CONCLUSIONS: A model of facial anatomy viewable from any angle in three-dimensional space was developed. The model has applications in medical education and, with future work, could play a role in surgical planning. This study emphasizes the role of three-dimensionalization of the soft tissues of the face in the evolution of aesthetic surgery.

Computer Simulation↗
PubMed2004

An anatomic and histologic analysis of the alar-facial crease and the lateral crus.

The key to achieving an excellent result following rhinoplasty lies in a strong fundamental knowledge of nasal anatomy. The purpose of this study was to analyze the anatomic and histologic relationship of the nose to the alar-facial crease. Fifteen cadaver noses were dissected and a total of thirty lower lateral cartilages were measured. Two fresh cadaver noses were fixed in neutral buffer formalin and embedded in paraffin. They were then sectioned into 6-mu coronal and sagittal sections and stained with hematoxylin and eosin, Eosin von Geison, and safranin to evaluate for collagen, elastin and muscle, respectively. Measurements of the lower lateral cartilages showed the average lateral crural height was 23.5 mm (+/- 2.5 mm), lateral crus width was 11.7 mm (+/- 1.5 mm), lateral domal width was 5.7 mm (+/- 0.9 mm), and intercrural distance was 20.2 mm (+/- 3.2 mm). No statistical differences were noted between male and female cadaver measurements. Histologic sections showed the area of the alar-facial crease to have a greater quantity of elastin fibers compared with muscle, collagen, or cartilage. These elastin fibers were predominantly orientated vertically (anterior-posterior) rather than horizontally (cephalo-caudad). This study demonstrates a higher ratio of elastin to collagen fibers in the region of the alar-facial crease.

Body Weights and Measures↗
PubMed2003

Scaphotrapeziotrapezoid arthrodesis: a follow-up study.

PURPOSE: The purpose of this study was to review the results of 800 scaphotrapeziotrapezoid fusions performed over a 27-year period. METHODS: The patients were evaluated for postoperative range of motion, grip and pinch strength, pain, return to work, arthritis, and complications. RESULTS: The overall range of motion was 70% to 80% of the nonoperated side and strength was 69% to 89%. Of the patients 88% returned to previous employment. Arthritis developed in 1.8% of the patients. The overall complication rate was 13.4%. CONCLUSIONS: Scaphotrapeziotrapezoid fusion is a viable treatment option especially for a high-functional-demand young population with significant wrist pathology. Complications, specifically nonunion, can be minimized with careful technique.

Adult↗
PubMed2003

Investigation of the growth and metastasis of malignant melanoma in a murine model: the role of supplemental vitamin A.

Vitamin A possesses both wound-healing and antitumor actions. Vitamin A-induced fibroplasia results in subsequent increased collagen production and deposition. This effect of vitamin A has been shown to result in the production of collagenous capsules around several murine breast and lung tumor systems. This tumor encapsulation process can potentially convert a systemic disease to a local one that can be easily treated by tumor excision. The goal of the present study was to determine whether supplemental vitamin A could promote the encapsulation of a murine melanoma. Sixty DBA/2J male mice were inoculated intracutaneously with 1 x 106 Cloudman S91 melanoma cells using a 30-gauge needle. The mice were divided into three groups: a control group, a pre-vitamin A group, and a post-vitamin A group. The control mice were fed a commercial chow containing 15,000 IU of vitamin A and 6.4 mg of beta-carotene per kilogram diet, considerably more than the National Research Council's recommended daily allowance of vitamin A for normal mice. The control diet was, therefore, not vitamin A-deficient. The pre-vitamin A mice were fed the basal chow supplemented with 150,000 IU of vitamin A per kilogram diet for 10 days before inoculation and for the remainder of the study. The post-vitamin A mice were fed the vitamin A-supplemented diet beginning on the day of inoculation and continuing for the remainder of the study. Sixty days after inoculation, tumor growth was assessed and the five mice remaining in each group were euthanized. Ventral skin at the site of inoculation was harvested for histologic assessment of local tumor growth and invasiveness. The liver and lungs of each of these mice were also harvested for histologic assessment of tumor metastasis. Sixty days after tumor inoculation, a 60 percent survival rate was observed in the control group as opposed to the vitamin A-supplemented animals, which demonstrated a 100 percent survival rate in both groups (n = 5 in each group). Decreased mean tumor size and gross tumor in most vitamin A-supplemented animals were statistically significant when compared with the control animals. The control animals had a mean tumor size of 26.1 mm, whereas the post-vitamin A group had a mean tumor size of 5.7 mm. One hundred percent of the control group exhibited tumor; one animal had distant metastases. The pre-vitamin A group did not exhibit any tumor growth, and the post-vitamin A group exhibited tumor growth in 40 percent of animals. Neither vitamin A-supplemented group showed any evidence of distant metastases. The animals supplemented with vitamin A demonstrated decreased tumor growth and metastasis. This in vivo model may indicate a potential prophylactic and therapeutic role for supplemental vitamin A in the treatment of malignant melanoma.

Animals↗
PubMed2003

Metopic synostosis: Defining the temporal sequence of normal suture fusion and differentiating it from synostosis on the basis of computed tomography images.

Only the metopic suture normally fuses during early childhood; all other cranial sutures normally fuse much later in life. Despite this, metopic synostosis is one of the least common forms of craniosynostosis. The temporal sequence of normal physiologic metopic suture fusion remains undefined and controversial. Therefore, diagnosis of metopic synostosis on the basis of computed tomography images alone can prove misleading. The present study sought to determine the normal sequence of metopic suture fusion and characterize both endocranial and ectocranial suture morphology. An analysis of computed tomography scans of 76 trauma patients, ranging in age from 10 days to 18 months, provided normative craniofacial data that could be compared to similar data obtained from the preoperative computed tomography scans of 30 patients who had undergone surgical treatment for metopic synostosis. Metopic suture fusion was complete by 6 to 8 months in all nonsynostotic patients, with initiation of suture fusion evident as early as 3 months of age. Fusion was found to commence at the nasion, proceed superiorly in progressive fashion, and conclude at the anterior fontanelle. Although an endocranial ridge was not commonly seen in synostotic patients, an endocranial metopic notch was virtually diagnostic of premature suture fusion and was seen in 93 percent of synostotic patients. A metopic notch was not seen in any nonsynostotic patient. The morphologic and normative craniofacial data presented permit diagnosis of metopic synostosis based on computed tomography images obtained beyond the normal fusion period.

Cranial Sutures↗
PubMed2002

Immediate versus delayed midface distraction in a primate model using a new intraoral internal device.

The theoretic advantage of distraction osteogenesis of the craniofacial skeleton, especially in cases of severe midface retrusion and in the presence of maxillary scarring, is prevention of relapse following significant advancements. The purpose of this study is to demonstrate the utility of a new low-profile, intraoral, internal device for midface distraction at the conventional or high Le Fort I level. In addition, the present study compares the efficacy of immediate versus delayed distraction on subsequent maxillary relapse. Four adult rhesus Macaca mulatta monkeys were divided into two groups. Group 1 underwent immediate midface distraction; group 2 underwent delayed distraction. All four monkeys underwent a modified Le Fort I osteotomy through an upper buccal sulcus incision and bilateral application of the intraoral midface distraction devices. No other osteotomies or incisions were necessary. Immediate distraction, performed in group 1, entailed intraoperative activation of the devices and distraction of 10 mm followed by a 5-day lag period before postoperative activation and distraction of an additional 10 mm at the rate of 1 mm/day. Delayed distraction, performed in group 2, entailed a 5-day postoperative lag period before device activation and distraction of 20 mm at the rate of 1 mm/day. Both groups thus underwent 20 mm of midface distraction. All devices were removed 6 weeks after completion of distraction. All monkeys tolerated the devices and daily distraction uneventfully. On the basis of serial cephalograms and dental models obtained throughout the experimental period, there was no evidence of relapse in either the immediate or delayed groups 6 months after distraction. In addition, on the basis of histologic, ultrastructural, and dry skull analysis, no significant differences were observed in the quality of regenerate bone obtained when comparing the immediate and delayed distraction groups. Significant midface advancement is thus feasible using this new internal, intraoral distraction device, which presents several advantages over other internal devices that require coronal incisions and additional osteotomies to achieve midface advancement. In addition, immediate distraction may abbreviate the distraction period without adverse sequelae.

Animals↗
PubMed2002

Applications of a new carbonated calcium phosphate bone cement: early experience in pediatric and adult craniofacial reconstruction.

Hydroxyapatite cements have recently been employed as bone substitutes in craniofacial reconstruction. They are easily applied, nonresorbable, available in unlimited quantity, and eliminate donor-site morbidity. Norian CRS (craniofacial repair system) is a new carbonated calcium phosphate paste that is unique in that it more closely resembles bone than do traditional hydroxyapatite pastes. Norian is a low-order crystalline apatite soluble at a low pH, facilitating its resorption and replacement by host bone. The cement was first used for craniofacial surgery in North America at the Children's Hospital of Philadelphia. This report presents the authors' experience with this bone substitute in both pediatric and adult craniofacial reconstruction. Sixteen adult and pediatric patients underwent craniofacial reconstruction involving the use of carbonated calcium phosphate paste for correction of defects that required from 5 to 110 g of carbonated calcium phosphate paste (mean, 28.5 g). The patients were all followed for a minimum of 14 months. Minor complications included one case of infection and two cases involving cement microfragmentation. In the authors' experience, carbonated calcium phosphate paste has proved to be an excellent alloplastic material for osseous augmentation and reconstruction in the craniofacial skeleton. Few problems were encountered using this material; no significant morbidity was encountered. Although this material seems to be promising as a bone substitute, further follow-up will be necessary to evaluate its potential role in craniofacial surgery.

Adolescent↗
PubMed2002

The fetal cleft palate: III. Ultrastructural and functional analysis of palatal development following in utero repair of the congenital model.

The role of fetal surgery in the management of congenital anomalies and intrauterine abnormalities is appropriately restricted on the basis of feasibility and risk-to-benefit analyses of intrauterine intervention. Recently, the authors demonstrated that in utero cleft palate repair of the congenital caprine model is technically feasible and results in scarless healing of the mucoperiosteum and velum, with subsequent development of a potentially functional bilaminar palate with distinct oral and nasal mucosal layers, following single-layer repair of the fetal mucoperiosteal flaps. A slight indentation at the site of repair was the only remaining evidence of a cleft. At 6 months of age, normal palatal architecture, including that of mucosal, muscular, and glandular elements, was seen grossly and histologically. The present work investigated the ultrastructural and functional aspects of the palate following in utero cleft repair to determine what benefits might be derived from fetal intervention. Six goats pregnant with twins were gavaged twice daily for 10 days (gestational days 32 to 41; term, 145 days) with dry, ground Nicotiana glauca plant delivering between 2.4 and 14 mg/kg per day of anabasine, doses that were adjusted in response to mater-nal toxicity. At 85 days' gestation, six fetuses underwent in utero palatoplasty using a modified von Langenbeck technique with elevation of bilateral mucoperiosteal flaps and lateral relaxing incisions. A single-layer repair of the mucoperiosteal flaps was performed using interrupted 6-0 Vicryl sutures. Six fetuses remained as unrepaired clefted controls. Six months after in utero palatoplasty, each group of goats underwent nasoendoscopy to evaluate palatal function; two unclefted 6-month-old goats served as controls. Subsequently, soft palate muscle was harvested from each of the goats and was evaluated by light and electron microscopy. Velar muscle was also harvested from the unclefted control goats and was similarly studied. Nasoendoscopy demonstrated functional palates capable of dynamic velopharyngeal closure following in utero cleft repair; this motion was similar to that observed in unclefted animals. Unrepaired clefted goats did not demonstrate any evidence of velar motion or velopharyngeal closure. Soft palate muscle from this group demonstrated evidence of myofibril degeneration, atrophy, and loss compared with unclefted control velar muscle. Ultrastructural changes included sarcomere "scalloping, " partial Z-line degeneration and loss, and progressive I-band degeneration and loss. Repaired clefted soft palate muscle was remarkably similar to unclefted control muscle. Significantly less myofibril, Z-line, and I-band degeneration and loss were observed with minimal evidence of sarcomere scalloping. In utero cleft palate repair results in a functional soft palate with restoration of ultrastructural architecture of the velum. These findings were attributed to reconstitution of the velar muscular sling, which is disrupted during the clefting process and remains abnormally inserted into the posterior edge of the palatal bone and along the bony cleft. Although repaired velar muscle does demonstrate some evidence of ultrastructural change compared with control muscle, these findings are significantly less pronounced than those observed in the unrepaired clefted muscle.

Animals↗
PubMed2002

Delayed cranial vault reconstruction for sagittal synostosis in older children: an algorithm for tailoring the reconstructive approach to the craniofacial deformity.

An algorithm for the management of sagittal synostosis in older children who underwent delayed cranial vault reconstruction is presented. This algorithm tailors the surgical approach to the specific craniofacial deformity present in each case. The scaphocephalic deformity characteristic of sagittal synostosis varies significantly when presentation is delayed beyond the first year of life, the time during which reconstruction is usually performed. Sixteen patients with sagittal synostosis who presented after 12 months of age, and were a mean of 3.2 years of age at the time of cranial vault reconstruction, were reviewed. Four patients demonstrated preoperative symptoms and objective findings indicative of increased intracranial pressure, including frequent headaches and emesis, papilledema, or digital markings on computed tomographic scan. Each of the 16 patients underwent either (1) single-stage total vault reconstruction with or without concomitant fronto-orbital expansion; (2) two-stage total vault reconstruction with anterior two-thirds vault expansion followed by transverse occipital expansion and recession a mean of 8.7 months later; or (3) anterior two-thirds vault reconstruction with or without fronto-orbital expansion. In each case, the extent of the scaphocephalic deformity determined the procedure used. The presence of severe frontal bossing associated with transverse restriction of the orbitotemporal region was an indication for fronto-orbital expansion in addition to vault reconstruction, whereas significant occipital protrusion was an indication for transverse posterior vault expansion and recession in addition to anterior two-thirds vault reconstruction. Excellent aesthetic results were obtained in all cases regardless of the type of reconstruction performed. However, it is essential that the extent of the deformity be carefully evaluated preoperatively to permit selection of the appropriate technique for reconstruction.

Algorithms↗