Does an In-House Computer-Aided Design/Computer-Aided Manufacturing Approach Contribute to Accuracy and Time Shortening in Mandibular Reconstruction?

Mandibular reconstruction using computer-aided design and computer-assisted manufacturing (CAD/CAM) techniques has received recent attention. This technique has theoretical advantages, although this approach can be commercially used in the limited area of the world.The aim is to describe our experience using in-house CAD/CAM guides and the situations in which CAD/CAM may present benefit in the region where commercial guides are unavailable.The authors developed our In-house CAD/CAM approach for mandibular reconstructions with a free fibular flap. Patients were divided into 2 group; CAD/CAM and conventional groups. In the CAD/CAM group, reconstructions were planned virtually using CAD/CAM; these CAD/CAM guides were used in the surgery. In the conventional group, free-hand cutting and fitting of the fibular segments were performed as reconstructions. Later, the bone computed tomographic image was compared with the plan. The averaged deviations and the percentages of the points within 1 mm, 2 mm, and 3 mm deviations were recorded. Total and ischemic time were also recorded.Reconstruction points within 1 mm deviation were 59% of CAD/CAM group (n = 9) and 42% of conventional group (n = 10, P = 0.04), within 2 mm 82% and 69% (P = 0.03). Total time were 1012 and 911 minutes, while flap ischemic time were 147 and 175 minutes (P = 0.03), respectively.In-house CAD/CAM mandibular reconstruction also supported accuracy and shorter flap ischemic time. For a detailed accurate reconstruction, CAD/CAM showed superiority than conventional method. Use of the In-house CAD/CAM guides might be an option where commercial guides are not available.

Using an In-House Approach to Computer-Assisted Design and Computer-Aided Manufacturing Reconstruction of the Maxilla.

PURPOSE: Computer-assisted design (CAD) and computer-aided manufacturing (CAM) techniques are in widespread use for maxillofacial reconstruction. However, CAD/CAM surgical guides are commercially available only in limited areas. To use this technology in areas where these commercial guides are not available, the authors developed a CAD/CAM technique in which all processes are performed by the surgeon (in-house approach). The authors describe their experience and the characteristics of their in-house CAD/CAM reconstruction of the maxilla. PATIENTS AND METHODS: This was a retrospective study of maxillary reconstruction with a free osteocutaneous flap. Free CAD software was used for virtual surgery and to design the cutting guides (maxilla and fibula), which were printed by a 3-dimensional printer. After the model surgery and pre-bending of the titanium plates, the actual reconstructions were performed. The authors compared the clinical information, preoperative plan, and postoperative reconstruction data. The reconstruction was judged as accurate if more than 80% of the reconstructed points were within a deviation of 2 mm. RESULTS: Although on-site adjustment was necessary in particular cases, all 4 reconstructions were judged as accurate. In total, 3 days were needed before the surgery for planning, printing, and pre-bending of plates. The average ischemic time was 134 minutes (flap suturing and bone fixation, 70 minutes; vascular anastomoses, 64 minutes). The mean deviation after reconstruction was 0.44 mm (standard deviation, 0.97). The deviations were 67.8% for 1 mm, 93.8% for 2 mm, and 98.6% for 3 mm. The disadvantages of the regular use of CAD/CAM reconstruction are the intraoperative changes in defect size and local tissue scarring. CONCLUSION: Good accuracy was obtained for CAD/CAM-guided reconstructions based on an in-house approach. The theoretical advantage of computer simulation contributes to the accuracy. An in-house approach could be an option for maxillary reconstruction.

A Case of Esophageal Submucosal Abscess Originating from a Peritonsillar Abscess.

We report the case a 54-year-old male patient who was admitted to our hospital with a sore throat and evidence of a high inflammatory reaction. Computed tomography revealed a peritonsillar abscess extending from the inferior right tonsil to the cervical esophagus, and thickening of the esophageal wall. The pharyngeal abscess was drained through an intraluminal incision in the mesopharynx. Culture of the abscess fluid showed growth of Streptococcus constellatus, one of the organisms of the Streptococcus milleri group. We diagnosed the patient as having phlegmonous esophagitis secondary to peritonsillar abscess. The inflammation was judged to have extended to the submucosal space of the esophagus from the pharyngeal mucosal space. Since the inflammation was contained within the esophageal wall and did not progress to mediastinitis, critical symptoms did not appear and the patient improved through conservative management with antibiotics

Axotomy alters alternative splicing of choline acetyltransferase in the rat dorsal motor nucleus of the vagus nerve.

Choline acetyltransferase of the peripheral type (pChAT) is a splice variant that lacks exons 6-9 of the common-type ChAT (cChAT); the role of pChAT remains unknown. We investigated the expression of pChAT and cChAT after axotomy to try to elucidate its function. In the dorsal motor nucleus of the vagus nerve (DMNV), nucleus ambiguus (NA), and hypoglossal nucleus (HN) of control rats, we observed neural expression of cChAT but no pChAT-positive neurons. Following nerve transection, we clearly detected pChAT-labeled neurons in the DMNV and weakly labeled neurons in the NA, but pChAT was not seen in the HN. In the DMNV, the mean number of cChAT-positive neurons decreased rapidly to 40.5% of control at 3 days post transection, and to 5.0% of control after 7 days. The number of cChAT-positive neurons then gradually increased and reached a plateau of about 25% of control value at 28 days post transection. pChAT-positive neurons did not appear until 7 days after transection. On the same day, pChAT mRNA was detected in the DMNV neurons by reverse transcription-polymerase chain reaction (RT-PCR) by using laser capture microdissection. The number of pChAT-positive neurons gradually decreased, and only 10% of the cholinergic neurons retained pChAT expression 56 days post transection. Double-immunofluorescence analysis showed that some of the DMNV neurons expressed both cChAT and pChAT upon recovery from axotomy. These results suggest that the expression of pChAT is associated with the regenerative or degenerative processes of motoneurons especially for general visceral efferents.

Localization of fibroblast growth factor-1 in cholinergic neurons innervating the rat larynx.

Cholinergic neurons in the dorsal motor nucleus of the vagus (DMNV) are particularly vulnerable to laryngeal nerve damage, possibly because they lack fibroblast growth factor-1 (FGF1). To test this hypothesis, we investigated the localization of FGF1 in cholinergic neurons innervating the rat larynx by immunohistochemistry using central-type antibodies to choline acetyltransferase (cChAT) and peripheral type (pChAT) antibodies, as well as tracer experiments. In the DMNV, only 9% of cChAT-positive neurons contained FGF1, and 71% of FGF1-positive neurons colocalized with cChAT. In the nucleus ambiguus, 100% of cChAT-positive neurons were FGF1 positive. In the intralaryngeal ganglia, all ganglionic neurons contained both pChAT and FGF1. In the nodose ganglia, 66% of pChAT-positive neurons were also positive for FGF1, and 90% of FGF1-positive ganglionic cells displayed pChAT immunoreactivity. Neuronal tracing using cholera toxin B subunit (CTb) demonstrated that cholinergic neurons sending their axons from the DMNV and nucleus ambiguus to the superior laryngeal nerve were FGF1 negative and FGF1 positive, respectively. In the nodose ganglia, some FGF1-positive cells were labeled with CTb. The results indicate that for innervation of the rat larynx, FGF1 is localized to motor neurons, postganglionic parasympathetic neurons, and sensory neurons, but expression is very low in preganglionic parasympathetic cholinergic neurons.

Participation of TRPV1 and TRPV2 in the rat laryngeal sensory innervation.

Laryngeal sensory innervation is essential to the laryngeal defense system. We investigated the participation of TRPV1 and its homologue TRPV2 in the rat laryngeal sensory innervation using immunohistochemistry and the neuronal tracer, fluoro-gold (FG). After injection of FG into the internal branch of the superior laryngeal nerve, FG-labeled neurons were seen in the rostral part of the nodose ganglion (NG). Neurons immunoreactive for TRPV1 or TRPV2 were distributed throughout the NG. TRPV1 immunoreactivity was seen in 49.0+/-4.5% of the FG-labeled neurons, while TRPV2 immunoreactivity was seen in 12.5+/-4.1% of the FG-labeled neurons. These findings suggest that both TRPV1 and TRPV2 participate in laryngeal nociception, but that TRPV1 may have a particularly important role.

Comparison of FGF1 (aFGF) expression between the dorsal motor nucleus of vagus and the hypoglossal nucleus of rat.

Neurons in the dorsal motor nucleus of the vagus (DMNV) are more severely affected by axonal injury than most other nerves, such as those of the hypoglossal nucleus. However, the mechanism underlying such a response remains unclear. In this study, we compared the expression of fibroblast growth factor 1 (FGF1), a neurotrophic factor, between the DMNV and the hypoglossal nucleus by RT-PCR and immunohistochemical analyses. RT-PCR showed that the level of FGF1 mRNA expression in the DMNV was lower than that in the hypoglossal nucleus (P<0.01). Immunohistochemistry revealed that FGF1 was localized to neurons. FGF1-positive neurons in large numbers were evenly distributed in the hypoglossal nucleus, whereas FGF1-positive neurons were located in the lateral part of the DMNV. Double immunostaining for FGF1 and choline acetyltransferase demonstrated that 22.7% and 78% of cholinergic neurons were positive for FGF1 in the DMNV and hypoglossal nucleus, respectively. A tracing study with cholera toxin B subunit (CTb) demonstrated that cholinergic neurons sending their axons from the DMNV to the superior laryngeal nerve were FGF1-negative. The results suggest that the low expression of FGF1 in the DMNV is due to severe damage of neurons in the DMNV.

Effective magnetic labeling of transplanted cells with HVJ-E for magnetic resonance imaging.

Magnetic labeling of transplanted cells permits us to monitor their localization non-invasively using MRI. Since most transfection agents for magnetic labeling have the same cationic charge as Fe(3+), the efficiency may be reduced. The hemagglutinating virus-envelope has no charge and utilizes membrane fusion activity to deliver internalized materials. In this study, we investigated the feasibility of using the envelope to incorporate paramagnetic Fe(3+) particles into PC12 cells and astrocytes. The envelope effectively labeled both cells with Fe(3+), which showed significant decreases of signal intensity in T2-weighted MRI. Labeled cells transplanted into the rat striatum were clearly visualized by T2*-weighted MRI at a magnetic field of 2 T. The results indicate that the hemagglutinating virus-envelope is a powerful tool for magnetic labeling.