Prospective comparison of panoramic tomography (zonography) and helical computed tomography in the diagnosis and operative management of mandibular fractures.

This prospective study compared the sensitivity of panoramic tomography (zonography) and helical computed tomography (CT) in diagnosing 73 mandibular fractures in 42 consecutive patients and correlated the results with known surgical findings. The purpose of the study was to determine the optimal radiologic examination for the diagnosis and operative management of mandibular fractures. The attending surgeons' interpretations of panoramic tomograms and helical CT images in the axial plane were compared with the patients' known surgical findings. A series of questions assessed the relative contribution of these two radiologic examinations in formulating an optimal operative plan for each patient. In the 42 patients studied, the sensitivity of helical CT was 100 percent in diagnosing mandibular fractures; this compared with 86 percent (36 of 42) for panoramic tomography, in which significantly more fractures were missed (p = 0.0412). In the six patients with fractures not visualized, the operative management was altered because of the new fracture visualized on helical CT. Of the seven missed fractures, six were in the posterior portion of the mandible. Comparing fracture detection by region, seven fractures found on helical CT were not visualized on panoramic tomography. Helical CT improved the understanding of the nature of mandibular fractures by providing additional information regarding fracture displacement and comminution and by locating injuries missed using panoramic tomography. This study suggests that helical CT alone may be more diagnostic than panoramic tomography alone in evaluating mandibular fractures. Helical CT sufficiently demonstrated details of fractures in 41 of 42 patients; in one patient, the nature of a dental root fracture was better delineated by panoramic tomography.

Contribution of conventional axial computed tomography (nonhelical), in conjunction with panoramic tomography (zonography), in evaluating mandibular fractures.

Previous studies comparing the sensitivity between different radiological exams have concluded that conventional axial computed tomography (CT; nonhelical) is unsuitable in the assessment of mandibular fractures. Axial CT was shown to have a reduced sensitivity compared with plain radiographs and panoramic tomography because it missed nondisplaced fractures in the posterior portion of the mandible. Because the resolution of CT has improved from the time of these previous studies, the authors were interested in assessing whether axial CT (nonhelical) could now provide additional clinically useful information and enhance our understanding of mandibular fractures, beyond that obtained from panoramic tomography alone. In their study, 5 staff surgeons initially evaluated the panoramic tomograms and then the CT scans of 39 patients with 66 fractures. A series of four questions assessed the relative contribution of these two radiological exams in formulating an optimal operative plan for each patient. The authors found that axial CT provided supplementary information regarding missed fractures, comminution, and the exact size and degree of displacement of fracture fragments. This additional data could have changed the operative plan in a substantial proportion of patients (17 of 39). Axial CT demonstrated two missed parasymphyseal fractures (2 of 39 patients) that were not seen on these patients' panoramic tomograms. Axial CT also revealed undiscovered comminution or demonstrated fracture displacement more precisely in 39% of patients (15 of 39) and 24% of fractures (16 of 66). This study demonstrates that axial CT was clinically useful as an additional investigation to panoramic tomography. Axial CT helped elucidate further the nature of suspected mandibular fractures.

Saline-filled breast implant safety and efficacy: a multicenter retrospective review.

Our center undertook an industry-funded, outcomes-based, multicenter, retrospective review to evaluate the safety and efficacy of saline-filled breast implants. Our review was part of a pre-market approval review process mandated by the U.S. Food and Drug Administration. The design of our review was modeled on a Plastic Surgery Educational Foundation outcomes study previously conducted by our center. For this study, several significant changes were made to our previous protocol, including improved patient tracking, stronger biostatistical support, and a mandatory 10-year minimum patient follow-up period. Physician-reported and patient-reported data on 450 patients with 882 saline-filled breast implants placed between January 1, 1980, and June 30, 1986, were obtained. Mean patient follow-up period was 13.0 years. Most implants (93.9 percent) were placed for breast augmentation. Seventy-four percent were placed in a submammary position; 25.6 percent, subpectorally; and 0.2 percent, subcutaneously. The overall complication rate was 20.2 percent. Reoperation for capsular contracture or implant deflation was necessary in 104 of 450 patients (23.1 percent). Deflation occurred in 73 implants (8.3 percent) and was underreported according to the physicians' record review alone. This deflation rate is higher than the 5.5 percent previously reported by our center. However, 26 of these 73 deflations (35.6 percent) occurred in a single cohort of patients at one center using Surgitek saline implants. If this cohort is excluded, the deflation rate drops to 5.8 percent, a figure more consistent with data published in the literature and found in our previous study. Of the 73 deflations, spontaneous deflation was reported for 50 (74.6 percent), and the remainder were iatrogenic. Actuarial survival of the non-Surgitek implants was 98.4 percent to 99.8 percent at 5 years and 96.9 percent to 98.9 percent at 10 years (95 percent confidence interval). Risk factors for implant deflation included the use of Surgitek saline-filled implants (odds ratio = 17.5, p < 0.01), use of Heyer-Schulte and Mentor model 1800 implants (odds ratio = 3.0, p < 0.01), and implant size greater than 450 cc (odds ratio = 1.01, p < 0.02). Risk factors for capsular contracture included submammary implant position (odds ratio = 2.05, p = 0.03) and implant size greater than 450 cc (odds ratio = 1.01, p < 0.01). Overall, satisfaction was high: 93 percent of patients were "satisfied" or "very satisfied" with their implants. As in our earlier study, risk factors for patient dissatisfaction were reconstruction after mastectomy (odds ratio = 7.6, p = 0.011), significant breast firmness (odds ratio = 6.2, p < 0.001), and patient desire for smaller implants (odds ratio = 3.0, p = 0.020). In conclusion, our review provides additional outcomes-based evidence that saline-filled breast implants remain a safe, effective alternative to silicone gel-filled models.

Latissimus dorsi myocutaneous flap reconstruction of neck and axillary burn contractures.

Neck and axillary burn contractures are both a devastating functional and cosmetic deformity for patients and a challenging problem for reconstructive surgeons. Severe contractures are more commonly seen in the developing world, a result of both the widespread use of open fires and the inadequacy of primary and secondary burn care in these vicinities. When deep burns are allowed to heal spontaneously, patients develop hypertrophic scarring of the neck and axillary areas. The back is typically spared, however, remaining a suitable donor site. We have used nine latissimus dorsi myocutaneous flaps in a total of six patients, finding the flaps effective in resurfacing both the neck and the axillary regions after wide release of burn contractures. Before flap mobilization, surgical neck release is often necessary to ensure safe, effective control of the airway in patients with significant neck contractures. Flap bulkiness in the anterior neck region can eventually be reduced by dividing the thoracodorsal nerve. Anchoring the skin paddle to its recipient site through the placement of tacking sutures will also help achieve a more normal anterior neck contour.

Nitric oxide mediates early dysfunction of rat and mouse islets after transplantation.

Evidence presented in this paper indicates that nitric oxide (NO), generated by a nonspecific "wound"-type of inflammation, is an important mediator of the early dysfunction of transplanted islets in rodents. Although allogeneic islets stimulate NO production to a greater degree than syngeneic islets, the amounts of NO produced after either are significantly elevated above baseline. Inhibition of NO production by N(G)-monomethyl-L-arginine (NMA), markedly decreases the time needed to restore euglycemia after intraportal transplantation of syngeneic islets in diabetic rats. The dose of NMA used was not observably toxic, with no significant changes in blood pressure, hepatic artery blood flow, serum hepatic enzyme levels, or in weight compared with control animals. In rat recipients of intraportal syngeneic transplants, evidence that NO is produced at the site of implantation includes (1) an early and transient increase in posttransplant hepatic vein nitrate levels (pretransplant, 90 microM; 24 hr, 230 microM; 48 hr, 250 microM; 72 hr, 170 microM; and 96 hr, 140 microM), (2) concurrent appearance of inducible NO synthase mRNA in liver extracts, and (3) immunohistochemical localization of inducible NO synthase within the transplanted islets. Suppression of NO production or inhibition of NO activity is a potential strategy to increase the early function and engraftment transplanted islets in the clinical setting.

Expression of intrahepatic inducible nitric oxide synthetase mRNA correlates with production of nitric oxide during intraportal isogeneic and allogeneic rat islet transplantation.

Intrahepatic NO production is related to the islet mass transplanted. Nitric oxide production is higher in recipients of allogeneic rather than syngeneic islets. In addition, in allogeneic recipients a possible second peak of NO production was observed at 120 hours corresponding to the time of cellular rejection of the islet grafts (P = .22 vs 96 hours). Finally, the time to rejection of Wistar rat donor islets transplanted into Lewis rat diabetic recipients treated with NMA was not affected. However, inhibiting NO production in the minimal islet transplant model decreased the time to islet function, it does not affect the time to clinical rejection in recipients of a high number of allogeneic islet, which functions immediately. High-level NO has been shown to inhibit T-cell activation in vitro, and thus decreasing the levels by administrating NMA may accentuate the rejection response, canceling out the beneficial effect that might otherwise have occurred on islet function. Further experiments are required to clarify these issues.

The role of nitric oxide in IL-1 beta-mediated dysfunction of rodent islets of Langerhans. Implications for the function of intrahepatic islet grafts.

Products of inflammation, such as interleukin-1 beta (IL-1 beta) and nitric oxide (NO), may impair early function of pancreatic islet grafts. In in vitro studies, freshly isolated rat islets of Langerhans cultured for 24 hr (10 islets/well) in the presence of 20 IU/ml of IL-1 beta released 57% less insulin (mean +/- S.E. of 151 +/- 61 microU) on the average than control (385 +/- 89 microU) cultures (n = 9, P = 0.08). Nitrite levels in the medium (indirect measure of NO) after islets were cultured for a 24-hr period were nearly 3-fold greater in IL-1 beta-exposed islets than control islet cultures (5.8 +/- 1.0 microM vs. 2.2 +/- 0.3 microM, P = 0.03). Production of nitrite by islet cells in the presence of IL-1 beta was inhibited in cultures also containing 2 mM L-NG-monomethyl-Arginine (L-NMMA) (3.4 +/- 0.4 microM, n = 9, P = 0.09 vs. control). When islets were maintained for 1 hr in 30 mg/dl glucose followed by 300 mg/dl for 1 hr, insulin release (stimulated) increased 6-fold (from 7 +/- 2 to 45 +/- 11 microU) in control cultures but only 3-fold (from 4 +/- 2 to 12 +/- 4 microU) in IL-1 beta-exposed cultures (n = 9, P = .01). Addition of 2 mM L-NMMA to islet cultures in the presence of IL-1 beta (20 IU/ml) (n = 9) restored insulin release to normal (from 6 +/- 2 to 38 +/- 9 microU, P > or = 0.6), suggesting that NO mediates the inhibitory effect of IL-1 beta on beta-cell function. In in vivo studies, rats with streptozotocin-induced diabetes (blood glucose > 400 mg/dl) received minimal (750 hand-picked islets) intraportal beta cell mass isografts with (n = 5) or without (n = 9) treatment with 100 mg/7 days of L-NMMA from 3 days before transplantation to 4 days after transplantation (POD -3 to +4). L-NMMA-treated rats became euglycemic (glucose < 200 mg/dl) earlier than nontreated rats (mean +/- SD of 6.4 +/- 2.5 vs. 16.7 +/- 4.7 days posttransplant, P = 0.001). These findings support the hypothesis that NO is a mediator of beta cell dysfunction after intraportal transplantation of freshly isolated islets of Langerhans.