Search PubMed⌕ Search

Biomedical subjects

J C Posnick

Publications and source records attributed to J C Posnick.

At least 73 records · Page 4Linked to original sources
PubMed1993

Surgical management of temporomandibular joint ankylosis in the pediatric population.

The treatment of temporomandibular joint ankylosis requires excision of the involved structures and immediate reconstruction. This paper presents a consecutive series of nine pediatric patients (mean age 7.7 years) who underwent a standardized treatment protocol to 13 affected joints. Four patients had unilateral temporomandibular joint ankylosis, five bilateral. One child required bilateral release but only unilateral reconstruction. Radiographic evidence demonstrated bony ankylosis in a total of 13 joints. Two patients had undergone surgical intervention of the temporomandibular joint before presentation to the authors. Two patients had preoperative temporomandibular joint pain. The cause of ankylosis was primarily traumatic or congenital. Our operative protocol included excision of the involved ankylotic structures through a coronal and Risdon incision, followed by immediate costochondral grafting. Fixation with miniplates and screws allowed for early mobilization. For unilateral patients, maximal incisal opening was improved from 5.4 mm before surgery to 24.8 mm after it, and for bilateral patients, from 6.0 to 17.5 mm. Mean follow-up was 2 years; only one patient was followed for less than 1 year. Pain symptoms were relieved after surgery. Perioperative complications were minimal, with no evidence of infection, facial nerve injuries, or bleeding. Patients with unilateral or bilateral ankylosis of traumatic cause achieved satisfactory functional results after surgery, while those in our bilateral congenital patients were far more limited. Rationales for this divergence in results are presented.

Adolescent↗
PubMed1993

Surgical correction of the Treacher Collins malar deficiency: quantitative CT scan analysis of long-term results.

This paper describes an alternative means of reconstruction of the Treacher Collins zygomatic deficiency and presents a consecutive patient series with long-term follow-up documented by clinical and quantitative means employing CT-derived craniofacial skeletal measurements. Eight children (mean age at operation 10.5 years) underwent bilateral zygomatic reconstruction with full-thickness, T-shaped calvarial bone grafts contoured three-dimensionally and then inset and stabilized with plate-and-screw fixation, with exposure provided only by a coronal incision. Orbital floor defects and graft donor sites were repaired with fixed split-thickness cranial bone. No complications occurred during surgery, and donor sites healed without clinical defect. Zygomatic augmentation was achieved in all patients, with follow-up ranging from 24 to 50 months (mean 35 months). CT scanning done before surgery, immediately afterward, and again 1 year or more later demonstrated significant increases in lateral orbital wall length, lateral orbital distance, interzygomatic arch distance, and zygomatic arch length. The late postoperative scans showed that these changes were maintained. However, effective treatment of the surrounding soft-tissue and eyelid deficiencies remains an unsolved problem.

Bone Transplantation↗
PubMed1993

Reconstruction of skull defects in children and adolescents by the use of fixed cranial bone grafts: long-term results.

This article presents the long-term results of skull defect reconstruction in a series of 27 children studied between 1986 and 1990 (mean age, 8.4 yr; range, 1-17 yr). Causes of their defects were encephalocele (six patients), trauma (seven patients), tumor (eight patients), fibrous dysplasia (two patients), postsynostectomy defects (two patients), osteomyelitis (one patient), and Reye's syndrome with bone flap loss (one patient). All patients underwent clinical and computed tomographic scan documentation of their skull defects before and immediately after surgery and at least 1 year later. The average preoperative defect surface area measured 33 cm2 (range, 2.5-114 cm2). Skull defects were reconstructed in all patients with fixed autogenous cranial bone grafts. In the initial five patients, the grafts were fixed with interosseous wires, and in the remainder, they were fixed with a combination of miniplates and microplates and screws. Follow-up ranged from 12 to 66 months (mean, 31.4 mo). Complications were minimal, with no infection, plate or graft exposure, or intracranial injuries. In 24 of 27 patients, clinical examination and computed tomographic scans showed no evidence of skull defect or appreciable irregularity of donor or recipient sites. Two patients had documented small regions of graft resorption. One skull had palpable contour irregularities but without a bony defect. All patients have resumed routine activities and sports without special head protection. Repair of skull defects in children with fixed autogenous cranial grafts is a reliable method of reconstruction with minimal morbidity. Although we prefer miniplates and microplates and screws for fixation, the grafts fixed in place with interosseous wires did equally well.

Adolescent↗
PubMed1993

Anthropometric and anthroposcopic findings of the nasal and facial region in cleft patients before and after primary lip and palate repair.

Two populations were studied and compared to determine the effects of cleft lip and palate surgery on the nose and face. In the first, three anthropometric measurements, two nasal and one facial, were taken before primary lip repair from infants with complete unilateral cleft lip and palate (UCLP) and with bilateral cleft lip and palate (BCLP). In the second, ten measurements were taken from the nose and face of patients surgically treated for UCLP and BCLP. The high frequency of noses disproportionately wide in relation to their height in both cleft types before primary lip repair greatly decreased after surgery. Among the residual deformities after surgery for UCLP, nostril floor width asymmetry was the most frequent, followed by columella length asymmetry, flat nasal bridge, wide soft nose, flat nasal tip, and small nasal tip protrusion. In the BCLP patients, nostril floor width asymmetry was also the most common stigma, followed by flat nasal tip, wide soft nose, columella length asymmetry, flat nasal bridge and bilaterally angled alae, and small nasal tip protrusion. A subnormally flat upper face inclination was observed in UCLP and BCLP patients. Quantitative determination of these nasal stigmata in cleft lip and palate patients who have undergone primary lip repair provides valuable information for surgical correction of the cleft soft-tissue deformities.

Adolescent↗
PubMed1993

Sagittal synostosis: quantitative assessment of presenting deformity and surgical results based on CT scans.

We reviewed our experience with nine consecutive patients with untreated isolated nonsyndromic sagittal synostosis. Using a method of 14 clinically relevant measurements taken from preoperative and postoperative CT scan images of these patients, we documented their presenting skeletal dysmorphology and the results of surgical correction at least 1 year after operation. Significant preoperative findings included an elongated cranial vault length that averaged 103 percent of normal and a narrowed cranial vault width both anteriorly at 92 percent and posteriorly at 86 percent of normal. Results of surgical correction, as documented by CT scan measurements, included normalization of the cranial length to 100 percent and of the anterior width to 101 percent of normal and improvement (but undercorrection) of the posterior width to 94 percent of normal. Quantitative measurement of CT scan images confirmed clinically observed findings in these patients before suture release and reconstruction and proved useful in assessing the surgical results achieved.

Child, Preschool↗
PubMed1993

Crouzon syndrome: quantitative assessment of presenting deformity and surgical results based on CT scans.

We reviewed our experience with 14 children who presented sequentially with untreated Crouzon syndrome and whose cranial vault presentation was with bilateral coronal synostosis. Using a method of 14 measurements in the cranio-orbitozygomatic region taken from preoperative and postoperative CT scans in these patients, we documented their presenting skeletal morphology and the results of surgical correction at least 1 year after operation. Our preoperative measurements confirmed a widened anterior cranial vault at 108 percent of normal and a cranial length averaging only 92 percent of normal. In comparison with age-matched controls, orbital measurements revealed a widened anterior interorbital distance at 122 percent of normal, an increased intertemporal width at 121 percent of normal, globe protrusion at 119 percent of normal, and a short medial orbital wall distance at only 86 percent of normal. The distance between the zygomatic buttresses and the interarch distance were found to be increased at 106 and 103 percent of normal, respectively. The zygomatic arch lengths were substantially shortened at only 87 percent of age-matched control values. These findings confirmed clinical observations of brachycephalic anterior cranial vaults with shallow, hyperteloric orbits and globe proptosis. Generally, in these patients the midface is horizontally retrusive and transversely wide, reflected in wide and shortened zygomas. Assessment of the postoperative results at least 1 year later showed no significant changes in any craniofacial measurements. Our findings indicate that early surgical attempts to decompress and reshape the cranio-orbital regions may limit the effects of increased intracranial pressure but do not correct the deformity as judged by CT scan evaluation at least 1 year later. Over the period of the study, the Crouzon deformity did not worsen after surgery, but the measurements remained far from normal.

Craniofacial Dysostosis↗
PubMed1993

Fetal tendon healing: development of an experimental model.

An experimental model was developed to study the process of fetal tendon healing. The flexor digitorum profundus tendons of the right hindlimb of 14 fetal lambs were partially lacerated at 100 days' gestation (term 145 days) and then studied macroscopically and histologically at several postinjury intervals (2, 4, 7, 14, 28, 42, and 56 days); two lambs were studied at each interval. A similar procedure was done in 14 adult sheep, who served as a control group. The fetal lambs showed no subcutaneous scarring, the digital sheath and tendon healed 2 weeks after injury, and a smooth, gliding surface was reconstituted. Collagen fibers were randomly arranged at 1 week but became organized along the tendon axis by 2 weeks. No adhesions, ruptures, or triggering was noted in the healing fetal tendons. Normal morphology was restored by 6 weeks. In the adult, dense subcutaneous scarring was noted, the digital sheath healed by 4 weeks and the tendon gap by 6 weeks, but a smooth gliding surface was not restored. Collagen fibers were randomly arranged at 2 weeks and became organized along the tendon axis by 4 weeks after injury. There were no dense adhesions or ruptures, but 25 percent of the tendons showed triggering.

Animals↗
PubMed1993

Fetal tibial bone healing in utero: the effects of miniplate fixation.

Although clinical and experimental findings have demonstrated that fetal soft-tissue wounds heal without scarring, very little is known about the process of fetal bone healing. This study examined fetal long bone healing in utero, both histologically and biochemically, with and without fracture fixation in a fetal sheep model. Our study group consisted of 25 live fetuses (from 16 ewes). There were 50 fetal tibias in this group; 12 were control, 17 were fixed (miniplate fixation), and 21 were nonfixed. A midshaft osteotomy of the tibia, either fixed or non-fixed, was performed on fetal sheep at 95 days' gestation (term = 145 days) in utero. The sheep were then killed at one of five postoperative time intervals (weeks 1, 2, 3, 4, and 7), and fetal bone healing was examined. The variables reviewed included gross morphology, histology, radiology, and collagen analysis (proportions of types II to I and III to I collagen). Fetal bone healing without fixation was accompanied by a large callus with rapid and abundant cartilage and collagen deposition. Bone healing was characterized by malunion or nonunion at 7 weeks. However, with miniplate and screw fixation, callus formation was minimal; primary bone healing occurred by 3 weeks and did not adversely affect long bone growth. Analysis of callus samples revealed a minimal amount of type III collagen, whereas the proportion of type II collagen was variable and proportional to the content of callus cartilage.

Animals↗
PubMed1993

Cervical spine subluxation associated with congenital muscular torticollis and craniofacial asymmetry.

The relationship between craniofacial asymmetry, congenital muscular torticollis, and cervical spine subluxation was examined in a study of 30 children who presented to our Craniofacial Program from 1987 through 1990. Twenty-six of the 30 patients had craniofacial asymmetry and muscular torticollis without true suture synostosis documented by head and neck CT scans. These 26 patients had positional skull molding with consistent flattening of the contralateral occipitoparietal region and the ipsilateral fronto-orbital region relative to the side of the torticollis. Thirteen of the 26 patients also were found to have a C1-C2 subluxation. C1 was rotated forward of C2 on the side contralateral to the muscular torticollis in 12 of 13 patients. None of the patients with subluxation had neurologic deficits or required spinal stabilization. Ophthalmologic evaluations demonstrated amblyopia (4 patients) and horizontal strabismus (1 patient), both thought to be coincidental, with no evidence of nystagmus in any case. Seven of the 26 patients required surgical therapy for their neck muscle tightness, while the remainder responded to physiotherapy. Only 2 of the 26 patients underwent cranio-orbital reshaping for correction of their upper face asymmetry. Recognition of cervical subluxation in patients with congenital muscular torticollis may help to explain residual head-neck posturing problems even after successful neck muscle therapy.

Birth Injuries↗
PubMed1993

Assessment of the preferred vertical position of the ear.

To determine the most desirable ear level (vertical position), a set of four drawings was assessed by 40 observers. Two levels were almost equally preferred when viewed in profile, one with the upper edge of the ear at the level of the most lateral point of the eyebrow and the other with the upper edge at the height of the upper eyelid. Various factors affecting the visual impression of auricular level and their clinical significance are discussed.

Adolescent↗
PubMed1992

Modification of the maxillary Le Fort I osteotomy in cleft-orthognathic surgery: the unilateral cleft lip and palate deformity.

Modifications of the Le Fort I osteotomy are described that allow for the simultaneous routine and safe management of maxillary hypoplasia, residual oronasal fistula, bony defects, soft-tissue scarring, and cleft-dental gap in adolescents with unilateral cleft lip and palate (UCLP). The results of this operation with 40 consecutive patients are presented, together with follow-up findings ranging from 15 months to 4 years 5 months. Parameters reviewed include cleft-dental gap closure, maintenance of attached gingiva at the cleft site, maintenance of a positive overjet and overbite, closure of residual oronasal fistula, the need for prosthetics to complete dental rehabilitation, and surgical morbidity. Thirteen of the patients also underwent simultaneous sagittal split osteotomies of the mandible, and 29 had a genioplasty performed. In 32 of the patients surgical cleft-dental gap closure was planned, and was successfully executed in all but one. Thirty-seven patients underwent successful simultaneous oronasal fistula closure, but in three cases, small residual fistulas remained. In all cases, attached gingiva was maintained in the region of the cleft site and along the tooth-bearing surfaces. Almost all of the patients maintained a positive overjet (39 of 40) and 85% maintained a positive (34 of 40) or at least neutral (4 of 10) overbite. Complications were few and generally not serious.

Adolescent↗
PubMed1992

Advantages of the postauricular coronal incision.

For exposure of the craniofacial skeleton above the Le Fort I level, the most frequently used approach is the coronal incision with a preauricular extension as needed. A modification of the coronal incision, using a postauricular incision, is presented that enhances its advantages and minimizes its disadvantages.

Child↗
PubMed1992

A modified occlusal splint to avoid tracheotomy for total midface osteotomies.

A modified occlusal splint is described which may be used to avoid tracheostomy when a total midface osteotomy is required. We demonstrate the accuracy of the modified splint by using the technique in a control subject who underwent alginate impressions, dental casts, and a face-bow transfer. A modified splint was constructed on the articulated dental models and was found to be accurate within the range of rotational movement of the temporomandibular joint. The technique is demonstrated in a patient with Crouzon's syndrome undergoing cranial vault reshaping and a monobloc (midface) advancement. The modified occlusal splint provides an alternative method of airway management when precise intraoperative occlusal relationships are important.

Child↗
PubMed1992

Chemotherapy and surgical resection combined with immediate reconstruction in a 1-year-old child with rhabdomyosarcoma of the maxilla.

Parameningeal head and neck rhabdomyosarcomas of childhood are often considered unresectable and are treated with irradiation and chemotherapy. High-dose radiation therapy has a very long-term detrimental effect on the developing face and also results in many other significant long-range complications. With the availability of advanced craniofacial surgical and free-tissue-transfer techniques, one-stage resection and immediate reconstruction, along with the use of effective preoperative and postresection chemotherapy instead of local radiation, may be the logical approach to the treatment of selected patients with chemosensitive parameningeal head and neck rhabdomyosarcomas.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Craniofacial skeletal measurements based on computed tomography: Part I. Accuracy and reproducibility.

Computed tomography (CT) is a useful modality for the management of craniofacial anomalies. A study was undertaken to assess whether CT measurements of the upper craniofacial skeleton accurately represent the bony region imaged. Measurements taken directly from five dry skulls (approximate ages: adults, over 18 years; child, 4 years; infant, 6 months) were compared to those from axial CT scans of these skulls. Excellent agreement was found between the direct (dry skull) and indirect (CT) measurements. The effect of head tilt on the accuracy of these measurements was investigated. The error was within clinically acceptable limits (less than 5 percent) if the angle was no more than +/- 4 degrees from baseline (0 degrees). Objective standardized information gained from CT should complement the subjective clinical data usually collected for the treatment of craniofacial deformities.

Adult↗
PubMed1992

Craniofacial skeletal measurements based on computed tomography: Part II. Normal values and growth trends.

Current diagnosis and surgical correction of craniofacial anomalies would benefit from accurate quantitative and standardized points of reference. A retrospective study was undertaken to define normal values for a series of craniofacial measurements and to evaluate the growth patterns of the craniofacial complex through axial computed tomography (CT). Fifteen measurements were taken from 542 CT scan series of skeletally normal subjects. The measurement values were then divided into 1-year age categories from 1 to 17 years, and into four age groups for those under 1 year of age. The normal range and growth pattern of measurement values for the cranial vault, orbital region, and upper midface are presented. The overall size of the cranio-orbito-zygomatic skeleton reaches more than 85 percent of adult size by age 5 years. The cranial vault grows rapidly in the first year of life but growth levels off early. The upper midface grows at a slower rate in infancy, but continues to grow later in childhood and early adolescence. Knowledge of the differential growth patterns and normal measurement values in the craniofacial region will help improve diagnostic accuracy, staging of reconstruction, precision of corrective surgery, and follow-up of patients.

Adolescent↗