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Biomedical subjects

L J Lo

Publications and source records attributed to L J Lo.

32 records · Page 2Linked to original sources
PubMed1997

Infantile myofibromatosis: a solitary lesion involving the upper lip.

Infantile myofibromatosis is a rare disease characterized by myofibroblastic proliferation, and typically occurs in early infancy. There is a wide spectrum of clinical presentation, which may involve various kinds of tissues in the body. Skin and subcutaneous lesions were the types of tissue most often seen. Although a multicentric form may behave aggressively, a solitary form of the tumor is benign with the possibility of spontaneous regression. Conservative management is justified after proper pathological diagnosis if the tumor involves an aesthetically important area. A case of solitary infantile myofibromatosis involving the upper lip is presented. Partial excision for biopsy was performed and long-term observation was undertaken. The tumor disappeared 3 years postoperatively.

Actins↗
PubMed1996

Plagiocephaly: differential diagnosis based on endocranial morphology.

Plagiocephaly is a descriptive term that connotes an asymmetrically oblique or twisted head. Such cranial dysmorphology has a number of etiologies, the most common of which are unicoronal synostosis, unilambdoid synostosis, and plagiocephaly without synostosis. Use of the term plagiocephaly in the literature is often ambiguous in that at times it is used inclusively for all etiologies while at other times it is used exclusively as a synonym for unicoronal synostosis. Although differentiation by physical examination among unicoronal synostosis, unilambdoid synostosis, and plagiocephaly without synostosis usually is possible for an experienced observer, inexperienced observers often have difficulty making an anatomically accurate diagnosis even with the assistance of conventional skull radiographs. High-resolution CT scans, including three-dimensional osseous surface re-formations, have become a standard element in the evaluation of craniofacial anomalies in many centers. We hypothesized that the three major etiologies of plagiocephaly could be unambiguously differentiated by means of endocranial three-dimensional CT osseous surface re-formations. Archival pretreatment CT data on 15 unicoronal synostosis, 4 unilambdoid synostosis, and 15 plagiocephaly without synostosis patients were reviewed to define, qualitatively and quantitatively, the characteristics of the endocranial base morphologies for each group; in addition to visual dysmorphology specific to each group, there was a statistically significant difference in the angle of deviation from the midlines of the anterior and posterior cranial fossae among unicoronal synostosis, unilambdoid synostosis, and plagiocephaly without synostosis. Four radiologists experienced in reading images of craniofacial anomalies were oriented to the group characteristics and then instructed to perform differential diagnosis for each of the 34 patients using only the endocranial three-dimensional CT images. The raters were blind to all other clinical and diagnostic information. The raters correctly diagnosed unicoronal synostosis. Errors were made in differentiation of unilambdoid synostosis and plagiocephaly without synostosis. These errors resulted from the raters' reliance on image inspection rather than quantitation of anteroposterior fossae midline angulation. Such quantitation unambiguously differentiated between unilambdoid synostosis and plagiocephaly without synostosis in the "error" cases. The endocranial base dysmorphology of patients with plagiocephaly is etiology-specific for unicoronal synostosis, unilambdoid synostosis, and plagiocephaly without synostosis. Three-dimensional CT endocranial base images can assist differential diagnosis of plagiocephaly.

Cephalometry↗
PubMed1996

Stability of fronto-orbital advancement in nonsyndromic bilateral coronal synostosis: a quantitative three-dimensional computed tomographic study.

Fronto-orbital dysmorphology in nonsyndromic bilateral coronal synostosis includes frontal flattening, supraorbital recession, and ocular globe protrusion. Surgical advancement of the supraorbital region ("bandeau") is performed to correct these deformities. A retrospective analysis of 10 consecutive patients with nonsyndromic bilateral coronal synostosis was performed to assess the effect of two types of bandeau fixation at the nasion. The advanced bandeau was fixed medially at the nasion with a calvarial bone graft and polyglycolic acid sutures (bone graft/suture group, five patients) or with a microplate (plate group, five patients) and bilaterally at pterion with calvarial bone grafts and polyglycolic acid sutures (all patients). The cranio-orbital dysmorphology and the surgical results were studied using pre-, peri-, and post-operative three-dimensional computed tomographic (CT) data. Reformation, manipulation, editing, and quantitative measurements of the CT data were performed on a computer workstation and Analyze imaging program. Four measurements performed to evaluate the fronto-orbital morphology: the length:width ratio of anterior cranial fossa, ventral globe index, cornea position, and supraorbital rim lag. The ventral globe index assessed the degree of eyeball protrusion out of the orbit cavity. Measurements of the cornea position and supraorbital rim lag were performed on the longitudinal orbit projections of the CT data. Six normal skull CT scans were available for same measurement and comparison. Measurements of the preoperative fronto-orbital dysmorphology in bilateral coronal synostosis were significantly different from those of normal subjects. One year after the surgery, the length:width ratio of the anterior cranial fossa was normalized in both groups. The ventral globe index was improved but not normalized in both groups, whereas the cornea position and supraorbital rim lag were improved in the bone graft/suture group but were normalized in the plate group. Based on the quantitative data, the surgical outcomes in the plate group were significantly better than those in the bone graft/suture group. Major relapse of surgical advancement in the bone graft/suture group seemed to occur in perioperative period. In summary, at 1 year postoperatively, the bandeau advancement improved but did not entirely normalize the fronto-orbital dysmorphology of nonsyndromic bilateral coronal synostosis in either group. We conclude that plate rigid fixation at the nasion provides superior stability for bandeau advancement compared with bone graft/suture fixation.

Bone Plates↗
PubMed1996

Orbital dysmorphology in unilateral coronal synostosis.

Unilateral coronal synostosis (UCS) produces overt craniofacial dysmorphology. UCS surgery in infancy aims to release the osseous restriction and normalize the fronto-orbital deformity. The quantitative effect of this surgery on the orbit and its contents is unknown. This study was conducted to quantify the preoperative orbital dysmorphology and its surgical outcome in patients with unilateral coronal synostosis. Twenty-eight UCS patients had preoperative three-dimensional computerized tomographic (CT) scans (at mean age 4.0 months), cranio-orbital reconstructive surgery (at 4.7 months), and postoperative scans (at 18.1 months). The CT data were analyzed using a computer workstation and AnalyzeTM biomedical imaging software. Four measurements were performed on both ipsilateral (same side as synostosis) and contralateral (opposite to synostosis) orbits of each scan: orbital index (OI, 100 x height/width of orbit), orbital cavity volume (OV), ocular globe volume (GV), and ventral globe Index (VGI, 100 x globe volume ventral to the anterior surface of orbital cavity/GV). The data were analyzed for statistical significance using Student's ttest. Preoperatively, the OI was significantly greater on the ipsilateral than on the contralateral side (113.7 vs. 87.3). There was a significant improvement on both sides of the orbit postoperatively, with ipsilateral 99.1 and contralateral 92.1. However, the difference between both sides remained significant. The OV was smaller in the ipsilateral orbits both pre- and postoperatively, with ipse/contralateral ratios of 95.8 and 95.2, respectively. Importantly, the GV was consistently smaller in the ipsilateral orbits preoperatively, with an ipse/contralateral ratio of 93.3. The ratio increased to 97.1 postoperatively, a statistically significant change. In the ipsilateral orbits, the preoperative VGI was significantly greater. The VGI improved postoperatively. These data indicate that UCS affects the development of the osseous orbit as well as its soft-tissue contents. After cranio-orbital surgery, there is diminution of asymmetry of both the bony orbit and its soft-tissue contents. Partial normalization of orbital dysmorphology occurred during the first postoperative year. UCS surgery in infancy does not prevent growth of orbital hard or soft tissues, and it seems to permit normalization of previously impaired growth.

Cephalometry↗
PubMed1996

Mandibular dysmorphology in unicoronal synostosis and plagiocephaly without synostosis.

Patients with unicoronal synostosis (UCS) or plagiocephaly without synostosis (PWS) have distinctive skull dysmorphologies. Associated mandibular dymorphologies have been suspected but not quantified. This study was performed to test the hypothesis that discrete mandibular dysmorphology exists in both UCS and PWS. All patients at a tertiary referral center at a medical school-affiliated children's hospital with confirmed diagnosis of UCS or PWS with adequate pretreatment CT data were included in the study population, which population was comprised of 20 UCS, 23 PWS, and 8 normal infants. Each patient had a head CT scan using 2-mm slices. 3-D images were created using Analyze, a biomedical imaging program. The mandibles were isolated, and the coordinates of 8 landmarks were sampled from each mandible by a single investigator: a single volume value was measured, and 9 linear distances and 4 angles were calculated. Corresponding measurements from each hemimandible were expressed as ratios of ipsilateral/contralateral side. In UCS, the affected side was defined as the side ipsilateral to the synostosis; In PWS, the affected side was defined as the side ipsilateral to the occipital flattening. The results from both groups were t tested for statistical significance. For UCS, statistically significant (p < .001) findings included: ipsilateral hemimandibular volume 5% smaller than contralateral; affected hemimandibular body length 1.9% shorter; affected gonial angle 2.6% more acute; affected coronoid process tilted anteriorly 2.5%; and distances from condylion and tip of the coronoid process to the chin landmarks 4% shorter on the affected side. For PWS, significant findings included: affected hemimandibular volume 3.8% larger; ramal height 3.5% shorter; mandibular body length 3% longer; and coronoid process tilted anteriorly by 2.3% on the affected side. In the UCS/PWS comparison, findings included: affected hemimandibular volume in UCS 8.7% less; affected gonial angle in UCS 3% more acute; affected mandibular corpus length in UCS 5% shorter; distances from the condylion and the tip of the coronoid process to the chin landmarks 4% shorter on the affected side in UCS. The hypothesized presence of diagnosis specific mandibular dysmorphology in UCS and PWS is confirmed. This analysis forms the baseline for study of the effects of unperturbed growth or therapeutic interventions upon the dentoskeletal dysmorphology of these anomalies.

Cephalometry↗
PubMed1994

Cleft lip and hemangioma: a patient with Wolf-Hirschhorn syndrome.

A patient with Wolf-Hirschhorn syndrome had multiple congenital anomalies and a right cleft lip. Hemangioma involved the full thickness of the upper medial lip segment at the age of 2 months, which caused lip repair to be very difficult. The first attempt at adhesion cheiloplasty resulted in complete separation. The tumor did not respond to steroid treatment. A subsequent trial of lip repair with the assistance of a tension-relieving suture tied to the nasal septum was successful. This type of tension suture is helpful to prevent dehiscence when security of lip closure is questionable or cannot be achieved.

Abnormalities, Multiple↗
PubMed1994

Craniofacial computer-assisted surgical planning and simulation.

Computer-assisted planning and simulation of craniofacial surgery has progressed from development, through validation, and into clinical use. CT scans are transferred from the radiology department to a graphics workstation in the surgeon's office or laboratory, where data postprocessing and visualization for anatomic evaluation and surgical simulation are performed. Quantitative and qualitative comparative analyses between the plan/simulation and the actual postoperative result provide the feedback that validates or refutes the preoperative assessment and simulated intervention. The optimum surgical solution can be chosen from many possibilities. Interactive computer-assisted surgical simulation is also useful for morbidity-free training of inexperienced surgeons.

Child↗
PubMed1993

Use of split anterior tibial muscle flap in treating avulsion injury of leg associated with tibia exposure.

Avulsion injury of the leg may result in exposure of the anterior surface of the tibia in addition to skin loss. This exposed bone should be covered by a soft tissue flap to facilitate healing and provide durability. The split anterior tibial muscle flap is ideal in this situation because of its adjacent location, reliability, and simplicity. A cadaveric study demonstrated rich intramuscle vascular anastomoses between the segmental branches from the anterior tibial artery that provide safety in partial transfer. The technique of split anterior tibial muscle flap was applied successfully in 4 patients with leg avulsion injury associated with tibial bone exposure. The cosmetic result was good and the function of the muscle was preserved.

Adult↗
PubMed1993

Proximal deletion of the long arm of chromosome 1: [del(1)(q23-q25)].

A patient with bilateral complete cleft of the lip and palate (CLP) had a proximal deletion of the long arm of chromosome 1 (1q). This rare chromosomal abnormality was characterized by pre- and postnatal growth retardation, psychomotor retardation, and specific craniofacial and other systemic anomalies. There is a high incidence of CLP in proximal 1q deletion syndrome, especially bilateral CLP. Twelve other cases reported in the literature having this deletion and associated anomalies were reviewed.

Abnormalities, Multiple↗
PubMed1993

Median facial dysplasia in unilateral and bilateral cleft lip and palate: a subgroup of median cerebrofacial malformations.

The median facial dysplasia group of patients is a unique, distinct, definable group characterized by mid-line facial deficiencies in the presence of a unilateral or bilateral cleft lip with or without cleft palate and without clinically detectable anomalies of the brain. This group of patients comprised 2 percent of new cleft lip and palate patients. The midline facial deficiencies in median facial dysplasia are characterized by a poorly defined Cupid's bow, absence of the labial frenulum and anterior nasal spine, deficient columella, and poorly developed septal cartilage and premaxilla. One of the central incisors may be absent or rudimentary. There are no definable gross abnormalities of the brain. The results of intelligence tests of median facial dysplasia patients have a normal distribution and are not significantly different from those of a noncleft normal population. Unoperated and operated median facial dysplasia patients all have typical midfacial growth disturbances below the norm for their ages. The classification of median facial dysplasia patients as well as other median cerebrofacial anomalies, the embryologic basis of these deformities, and the clinical results of their treatment are helpful in understanding some of the problems related to the treatment of the cleft lip and palate patient. Median facial dysplasia patients demonstrate an inherent potential for poor midfacial growth. Deficiencies of soft tissue such as a lack of the Cupid's bow make it difficult to reconstruct the lip and nose satisfactorily.

Abnormalities, Multiple↗
PubMed1992

Facial midline and symmetry: modified face bow.

A facial "cone" can be drawn inside the head. The apex of the cone is the midpoint of the line that connects both ear canals, point C, and the face is the base. A modified face bow is designed with holes through which a Steinmann pin is passed, meeting at the apex of the facial cone. After the ear bolts are symmetrically fixed, the Steinmann pin through the central hole follows the midline of the face as the bow rotates from the forehead to the chin. The right and left facial bony protrusions can be evaluated by two Steinmann pins projecting through the corresponding holes on the face bow. This device is utilized to determine the facial midline and facial symmetry during surgery. It also can be used as a tool for anthropologic studies.

Equipment Design↗
PubMed1992

A simple and effective method of compression dressing for skin grafts.

Skin grafting is one of the most common procedures in plastic and reconstructive surgery. Various methods of fixation and dressing, to achieve good approximation and immobilization of skin grafts and, thus, to bring about better graft survival, are described. A simple method utilizing readily available latex and staples provides good fixation and compression. This technique has been applied in 50 patients requiring skin grafts. The morbidity and complications were minimal, and the grafts have taken satisfactorily. Pressure study with an animal model has revealed adequate compression.

Animals↗
PubMed1991

Free flap transfer in burn reconstruction.

Wound healing in burn patients with exposure of vital tissues has been greatly facilitated by the use of free flap transfers for reconstruction with good functional as well as aesthetic results. Preoperative angiography is not an indispensable way to localize recipient vessels. Knowledge of the changes that occur in vessels at the zone of injury is crucial in the selection and preparation for microsurgical anastomosis. One team approach is advocated because the plan for the procedure may be changed when no appropriate recipient vessel is located during the dissection. We present our study of ten cases followed up in the last six years. Nine cases were successful, and severe wound infection resulted in one flap failure. Proper recipient vessel selection and adequate wound debridement are important factors for successful free flap transfer in burn reconstruction.

Adult↗