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The aim of the study was to compare in a randomized controlled clinical trial the use of the piezoelectric osteotomy as an alternative to the conventional approach in terms of surgery time, intraoperative blood loss, cut quality, nerve injury, and costs. One hundred ten patients who had orthognathic surgery procedures with bimaxillary osteotomy were divided into 2 groups: group A was treated with a piezosurgery device, and group B, with a reciprocating saw and bur. The piezosurgical bone osteotomy permitted individualized cut designs. The surgical time in group A was reduced, with a mean for the mandibular osteotomy (1 side) between 3 minutes 31 seconds and 5 minutes 2 seconds, whereas in group B, the surgical time was between 7 minutes 23 seconds and 10 minutes 22 seconds. The surgical time in group A for the Le Fort I osteotomy was between 5 minutes 17 seconds and 7 minutes 55 seconds in group A and between 8 minutes 38 seconds and 15 minutes 11 seconds in group B. All patients in group A had a low blood loss (G300 mL) versus patients of group B who had a medium to high blood loss (medium loss: 400 mL, high loss: 9500 mL). Inferior alveolar nerve sensation was retained in 98.2% of group A versus 92.7% in group B at 6 months postoperative testing. Piezoelectric osteotomy reduced surgical time, blood loss, and inferior alveolar nerve injury in bimaxillary osteotomy. Absence of macrovibrations makes the instrument more manageable and easy to use and allows greater intraoperative control with higher safety in cutting in difficult anatomical regions.

Although numerous biomaterials are used for maxillarysinus-lift surgery, the ideal material for such procedures has notyet been identified. Both heterologous and alloplastic bone substituteshave a solely osteoconductive effect and lack the osteoinductiveproperties of the bone morphogenetic proteins typical ofautologous bone. Our group assessed a new alloplastic graft material,poly(lactic-co-glycolic) acid/hydroxyapatite (PLGA/HA),implanted in a human model of maxillary sinus-lift surgery. Forthis prospective, random, double-blind trial, we used deproteinizedbovine bone (DBB) as the comparison material. Radiographic bonevertical height and density were assessed at approximately 28 weeksafter grafting using cone-beam computed tomography. The verticaldimension of the regenerated bone was equivalent between the2 groups. The density of the bone regenerated using PLGA/HA wassignificantly lower than that obtained with DBB. Despite clinicalassessments demonstrating that PLGA/HA has sufficient characteristicsfor use in sinus-lift surgery, DBB provided greater bonedensity and an equivalent vertical dimension of grafted bone. Furtherstudies are needed to supplement the radiologic findings with histologicand micromorphometric examinations.

OBJECTIVE AND IMPORTANCE: Sinus histiocytosis or Rosai-Dorfman disease (RDD) is a rare but well-recognized disorder characterized by an unusual proliferation of histiocytic cells. Intracranial localization is a rare manifestation of RDD. Only three cases of localization in the posterior fossa have been reported in the literature. The present report describes the first case, to our knowledge, of cerebellar localization of RDD. CLINICAL PRESENTATION: A 67-year-old woman was admitted to our institution with a 5-month history of cerebellar ataxia. Her medical history was unremarkable. The patient was alert and cooperative. No cranial nerve deficits were evident; Romberg positivity to the left side was recorded. No cutaneous abnormalities, lymphadenopathy, or hepatosplenomegaly were revealed by physical examination. Routine hematological and biochemical studies were normal except for the erythrocyte sedimentation rate, which was elevated. Radiologically, the lesion appeared as a well-defined and avascular mass in the right cerebellar lobe. Meningioma was considered the most likely diagnosis. TECHNIQUE: The patient underwent a suboccipital craniotomy with complete excision of the lesion. Microscopic examination of the operative specimen revealed the presence of a mixed cellular population with predominant mature histiocytes. A peculiar feature was the presence of lymphocytes and monocytes within the cytoplasm of histiocytes (emperipolesis). Immunohistochemical study of the histiocytes revealed strong positivity for S-100, CD-68 antigen, and vimentin. CONCLUSION: Involvement of the central nervous system in RDD appears to have a benign prognosis, especially in the absence of nodal diseases. Surgery is essential for diagnosis, and, when total removal is achieved, the outcome is generally good without risk of recurrence.

Scanning electron microscopy (SFM) and transmission electron microscopy (TEM) were used to examine the morphological aspects of peri-implant mucosa around abutments of differing geometry (biconical and cylindrical) and of differing surface micromorphology. The samples were taken from seven patients who had undergone implant surgery at least one year prior to the study. In samples from biconical abutments, SEM of the sulcular epithelium showed that it consisted of flattened polygonal cells with a surface resembling a honeycomb. Superficial desquamation was rarely found. In contrast, in the samples from cylindrical abutments, the sulcular epithelium showed extensive desquamation and surface irregularity, but not the honeycomb structure in its superficial cells. TEM showed in both abutment types a morphologically normal epithelium, with a normal maturation cell pattern. Desquamation of the more superficial layers of the epithelium, associated with thinning in the superficial layer of flattened cells, was more evident around cylindrical abutments. In the transitional area between the sulcular and junctional epithelium, an intra-epithelial leukocyte infiltrate, and a larger amount of keratohyalin granules in the more superficial cells was observed. The morphological differences in peri-implant mucosa between the two abutment types may be related to differences in morphology of the metal surfaces of the abutments themselves.

A large number of experimental data suggest a possible biochemical hypothesis for the trigger stimulus of cerebral vasospasm after subarachnoid hemorrhage (SAH). Among several classes of possible spasmogens, arachidonic acid metabolites may play a primary role. Authors have measured with radioimmunoassay technique (R.I.A.) the levels of four arachidonate metabolites (PGD2, TxB2, 6-keto-PGF1 alpha and i-LTC4) in lumbar and cisternal cerebrospinal fluid (CSF) of patients admitted with diagnosis of aneurysmal SAH. In all cases a significant activation of arachidonate metabolism is found, if compared to control cases. Patients with demonstrated vasospasm have significantly higher CSF levels of PGD2 and i-LTC4. Cisternal CSF levels of four metabolites are significantly higher than lumbar CSF levels. This suggests the correlation between subarachnoidal clot extension and the risk for vasospasm. Authors also present an experimental animal model of SAH, which is reliable from a pathological standpoint. This model could be therefore used in the study of neurochemical and neuropharmacological aspects of SAH.