ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Premature fusion of multiple cranial sutures has been associated with increased intracranial pressure and the potential for mental impairment. Isolated craniosynostosis, however, has been thought to be a benign condition primarily reconstructed for aesthetic purposes. On the basis of subjective developmental improvement postoperatively, an objective radiographic analysis (single positron emission computed tomography [SPECT]) was used to assess differences in cerebral perfusion in the areas compressed secondary to the fused cranial suture both before and after cranial reconstructive surgery in patients with simple craniosynostosis. Seven children with craniosynostosis, six boys and one girl (age range, 3–28 months), were enrolled in this prospective study. Six of the seven had cranial asymmetry on preoperative cranial computed tomographic scans, and one had a symmetric defect and was used as a control. Each subject had a preoperative SPECT scan approximately 3 to 5 days before the cranial reconstruction procedure and a follow-up scan 6 to 10 weeks postoperatively. Preoperative asymmetries in cerebral perfusion ranged from 0 to 30 (mean, 13±) in the areas compressed secondary to the premature suture fusion. In five patients cerebral blood flow, which was asymmetric before surgery, became symmetric after craniofacial reconstruction, and no new perfusion defects were documented. The control patient and one other patient had symmetric perfusion both pre- and postoperatively. Craniosynostosis may be associated with decreased cerebral blood flow as a result of the constriction of the brain from the prematurely fused suture. The correction of asymmetric cranial single-suture synostosis is more than a cosmetic procedure in that it allows for normalization of cerebral blood flow. This difference in blood flow supports early surgical intervention to prevent any potential central nervous system compromise secondary to abnormal blood flow.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Mandibular distraction osteogenesis has gained popularity for the treatment of mandibular hypoplasia and asymmetry. With this technique, significant skeletal and soft tissue changes in the lower face can be produced in a relatively short time period without the need for extensive surgery. Despite general acceptance, the long-term sequelae of the procedure have not been well documented. In this report, we describe two patients who experienced changes in their articulation and velopharyngeal function after unilateral mandibular distraction. The first patient underwent 35 mm and the second patient 45 mm of mandibular lengthening. In both cases, articulation skills declined, and there was velopharyngeal inadequacy immediately after distraction. However, in both cases, the velopharyngeal inadequacy was transient; one patient recovered near-normal velopharyngeal function within 1 month after distraction and the second patient recovered function within 8 months. The relations among mandibular distraction, articulation, and velopharyngeal function are discussed.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The exothermic reaction produced during the polymerization of polymethylmethacrylate yields temperatures in excess of 180°F (81.4°C). At these elevated temperatures, significant bone and dural necrosis occurs. In an attempt to prevent thermal injury during craniofacial surgery, surgeons irrigate the polymerizing implant with cold saline, assuming that this will decrease both the absolute temperature elevation and the duration of the exothermic reaction, making the use of methylmethacrylate safe. Unfortunately, no experimental evidence exists to support this claim. To test the safety of methylmethacrylate during craniofacial surgery, we constructed an in vitro model that allowed us to measure directly the heat transferred from the methylmethacrylate to the underlying dura or bone during polymerization. In this model, the methylmethacrylate implants were 6 cm in diameter, but they varied in thickness. We hypothesized that methylmethacrylate could be safely applied up to a certain thickness, after which the temperature rise on the undersurface of the implant would no longer be controlled by any amount of cold saline irrigation, and thermal necrosis would occur. We found that without irrigation all implants produced temperatures in excess of 180°F (81.4°C) internally. This peak temperature lasted for approximately 45 seconds and then declined to a baseline temperature of 98°F (36.3°C) over 5 to 6 minutes. Upon irrigation of the implants with cold saline (4°C), the level and duration of temperature elevation conducted to the underlying surface varied significantly on the basis of implant thickness. Implants smaller than 5 mm thick produced temperatures on the bone surface of 108°F (41.8°C) for 11 seconds. This temperature control was partially lost at 7 mm when the underlying surface reached a temperature of 134°F (56.1°C) for 15 seconds. Methylmethacrylate implants with a thickness greater than 7 mm produced temperatures of 145°F (62.2°C) for 22 seconds, indicating that the cold was insufficient to protect against thermal injury. Therefore, we conclude that polymethylmethacrylate can be applied safely to the skull if the implant is 6 mm thick or smaller. With polymethylmethacrylate thicker than this, the heat produced during polymerization cannot be controlled, and thermal necrosis to the underlying tissues is inevitable.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Surgical access to the anterior skull base for resection of midline tumors is commonly performed through a transfacial approach. We describe a new, open trans-nasal approach to the midline skull base and adjacent pituitary region. This technique, devised through our experience with open septorhinoplasty, was initially studied on fresh cadaver heads. It has subsequently been used in 28 consecutive patients for the resection of a variety of midline skull base tumors. We believe that this approach is superior to the traditional rhinal and sublabial transfacial techniques because of the wider exposure and true midline orientation that it offers. In addition, no mucosal membrane is violated, therefore providing a greater seal of the dissection postoperatively. A detailed description of the technique and the results of its clinical use are presented.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Bregmatic masses often present a challenging diagnostic dilemma. We present two illustrative cases to demonstrate this clinical problem and present our recommendations for evaluation and treatment.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Orbital surgery is of critical importance within the framework of craniofacial surgery. The conical conformation of orbits requires analysis and surgical procedure planning methods involving all three dimensions. We present our protocol for the analysis and our three-dimensional surgical procedure plan to treat orbital malformations using teleradiography and two- and three-dimensional computed tomographic imaging. A number of clinical cases treated according to this approach are also presented.

ISSN:1049-2275    

出版商:OVID    

年代:1996

数据来源: OVID