Unilateral hypoglossal nerve palsy following orthognathic surgery: A case report and literature review.

INTRODUCTION: Hypoglossal nerve palsy (HNP) can be caused by nerve damage from the central nerve to a peripheral nerve, and individuals with multiple factors could be predisposed to HNP. We report a case of isolated unilateral HNP after orthognathic surgery. CASE PRESENTATION: A 56-year-old Japanese woman complained of jaw distortion and malocclusion. She had undergone a Le Fort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) under general anesthesia in August 2021. On postoperative day 3, she experienced tongue motility, and when the tongue protruded forward, the tongue tip shifted to the right, and swelling of the right lateral pharyngeal wall was observed. An additional blood test revealed increased antibody titer levels (40×), cytomegalovirus IgG EIA titer (16.9 U/mL), HSV-IgG EIA titer (40 U/mL), and EBV-viral capsid antigen (VCA) IgG EIA titer (1.4 U/mL). We administered valacyclovir hydrochloride 1000 mg/day for 7 days, prednisolone (PSL) 60 mg/day, mecobalamin 1500 µg/day, and adenosine triphosphate (ATP) disodium hydrate 300 mg/day. A neurological examination revealed no central lesions, and we continued the patient's tongue-function training and oral hygiene guidance. The tongue apex deviation was resolved approx. 3 months postoperatively. DISCUSSION: There are no major reports on the etiology of HNP after orthognathic surgery. The possibility of HNP triggered by endotracheal intubation or through packing gauze under general anesthesia and viral infection cannot be ruled out. CONCLUSION: Clinicians should be aware of the possibility of unilateral HNP following orthognathic surgery.

The Role of Hedgehog Signaling in the Melanoma Tumor Bone Microenvironment.

A crucial regulator in melanoma progression and treatment resistance is tumor microenvironments, and Hedgehog (Hh) signals activated in a tumor bone microenvironment are a potential new therapeutic target. The mechanism of bone destruction by melanomas involving Hh/Gli signaling in such a tumor microenvironment is unknown. Here, we analyzed surgically resected oral malignant melanoma specimens and observed that Sonic Hedgehog, Gli1, and Gli2 were highly expressed in tumor cells, vasculatures, and osteoclasts. We established a tumor bone destruction mouse model by inoculating B16 cells into the bone marrow space of the right tibial metaphysis of 5-week-old female C57BL mice. An intraperitoneal administration of GANT61 (40 mg/kg), a small-molecule inhibitor of Gli1 and Gli2, resulted in significant inhibition of cortical bone destruction, TRAP-positive osteoclasts within the cortical bone, and endomucin-positive tumor vessels. The gene set enrichment analysis suggested that genes involved in apoptosis, angiogenesis, and the PD-L1 expression pathway in cancer were significantly altered by the GANT61 treatment. A flow cytometry analysis revealed that PD-L1 expression was significantly decreased in cells in which late apoptosis was induced by the GANT61 treatment. These results suggest that molecular targeting of Gli1 and Gli2 may release immunosuppression of the tumor bone microenvironment through normalization of abnormal angiogenesis and bone remodeling in advanced melanoma with jaw bone invasion.

Association between impaired healing after orthognathic surgery and irritable bowel syndrome: A case report and literature review.

INTRODUCTION: In the disease irritable bowel syndrome (IBS), gastrointestinal function is worsened even though no organic abnormalities are observed in the gastrointestinal mucosa. We report the case of an orthognathic surgery patient with suspected irritable bowel syndrome. CASE: In September 2017, a 15-year-old Japanese female was referred to us with dental crowding, malocclusion, and mandibular protrusion. In June 2019, a disagreement with classmates led to abdominal pain, diarrhea, and hemorrhage; in August 2019, a preoperative blood test showed sudden anemia, and her surgery was thus postponed. Subsequent upper and lower gastrointestinal endoscopy revealed no organic abnormality, and no definitive diagnosis was made. In March 2020, after an improvement in anemia was observed, a segmental Le Fort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) were performed under general anesthesia. On the third post-operative day, due to the mucosal dehiscence adjacent to the suture part, the titanium plate was exposed, and irrigation of the wound with normal saline solution and oral hygiene instruction was continued daily for 2 weeks. Two years and eight months have passed since the surgery, and the healing of the oral mucosa and bone has been uneventful. DISCUSSION: The relationship between IBS and post-operative impaired healing associated with the fragility of the oral mucosa is unknown. However, psychological stress has been reported as a cause of IBS and to be related to oral microorganisms. CONCLUSION: Reducing risk factors for IBS and maintaining proper perioperative oral hygiene is essential in managing similar cases.

Surgical procedures for correcting vertical maxillary excess: A review.

INTRODUCTION: Vertical maxillary excess, a common orthodontic problem that leads to long faces and open bites, can be repositioned with a Le Fort I osteotomy. However, the Le Fort I osteotomy poses the risk of a variety of complications including descending palatine artery (DPA) injury. Although several Le Fort I osteotomy modifications were reported to avoid complications associated with this osteotomy, only a few of such studies were conducted in Japan, and details remain scarce. PATIENTS AND METHODS: We performed a literature review regarding modifications of Le Fort I osteotomies, including Le Fort I with a horseshoe osteotomy, modified horseshoe osteotomy, unilateral horseshoe osteotomy, pyramidal osteotomy, and U-shaped osteotomy. We identified eight relevant studies conducted in Japan; one study did not provide the number of patients examined. The 77 patients (seven studies) with vertical maxillary excess who underwent orthognathic surgery were ≥17 years old. DISCUSSION: There were no severe complications after the modified Le Fort I osteotomies. The postoperative maxillary changes obtained by the conventional horseshoe, modified horseshoe, unilateral type of horseshoe, pyramidal, and U-shaped osteotomies were nearly repositioned to the planned position and remained stable for ≥12 months post-surgery. CONCLUSION: Our review indicates that preserving the DPA can lower the incidence of intra- and post-operative complications. Each modification of the Le Fort I osteotomy (i.e., conventional horseshoe, modified horseshoe, unilateral horseshoe, pyramidal, and U-shaped osteotomy) has its respective advantages and indications.