Radiographic analysis of critical anatomical structures for pterygoid implant placement in Chinese patients with a severely atrophied maxilla.

The pterygoid implant is a feasible alternative for posterior dental rehabilitation without grafting; however, the ideal pterygoid implant placement continues to be debated. The aim of this study was to identify effective landmarks and establish valid guidelines to determine the ideal pterygoid implant placement. Cone beam computed tomography (CBCT) data of 100 severely atrophied maxillae requiring implant rehabilitation, obtained between January 2015 and December 2018, were included. The CBCT data were obtained in DICOM format from the radiographic database and imported into Nobel Clinician software (Nobel Biocare) for radiographic analysis. Virtual pterygoid implant placement was successful in 67 maxillae: a 13-mm virtual implant in four maxillae (6.0%), 15-mm in 52 maxillae (77.6%), and 18-mm in 11 maxillae (16.4%). For the virtual pterygoid implant, the mean implant angulation± standard deviation in the anteroposterior axis (sagittal view) was 45.08 ± 2.56° relative to the Frankfort plane. In the buccopalatal axis (coronal view), the mean implant angulation was 64.30 ± 4.99° relative to the Frankfort plane and the mean value for the shortest linear distance between the palatine canal and apical tip of the virtual implant was 3.91 ± 0.62 mm. A 15-mm pterygoid implant placed at 45° in the anteroposterior axis and 60° in the buccopalatal axis (relative to the Frankfort plane), is generally recommended in this Chinese patient population.

Randomized controlled trial of standard versus high-dose intravenous omeprazole after endoscopic therapy in high-risk patients with acute peptic ulcer bleeding.

BACKGROUND: Rebleeding from peptic ulcers is a major contributor to death. This study compared standard (40-mg intravenous infusion of omeprazole once daily for 3 days) and high-dose (80-mg bolus of omeprazole followed by 8-mg/h infusion for 72 h) in reducing the rebleeding rate (primary endpoint), need for surgery, duration of hospital stay and mortality in patients with peptic ulcer bleeding after successful endoscopic therapy. METHODS: This was a single-institution prospective randomized controlled study based on a postulated therapeutic equivalence of the two treatments. All patients who had successful endoscopic haemostasis of a bleeding peptic ulcer (Forrest classification Ia, Ib, IIa or IIb) were recruited. Informed consent was obtained and patients were randomized to receive standard- or high-dose infusions of intravenous omeprazole. RESULTS: Two (3 per cent) of 61 patients in the high-dose group and ten (16 per cent) of 61 in the standard-dose group exhibited rebleeding, a difference of - 13 (95 per cent confidence interval - 25 to - 2) per cent. The upper limit of the one-sided confidence interval exceeded a predefined equivalence absolute difference of 16 per cent. Equivalence of standard- and high-dose omeprazole in preventing rebleeding was not demonstrated. CONCLUSION: Intravenous standard-dose omeprazole was inferior to high-dose omeprazole in preventing rebleeding after endoscopic haemostasis for peptic ulcer bleeding. REGISTRATION NUMBER: NCT00519519 (http://www.clinicaltrials.gov).

Does a mandibular access osteotomy improve survival in pT2 oral tongue cancers? Retrospective study at a single institution.

The surgical approach to the resection of oral tongue cancers can involve transoral resection (TOR) or a temporary mandibulotomy access (TMA). There are no relevant guidelines, and the oncological safety of TOR needs consideration. The objective of this study was to investigate TMA and TOR in pT2 oral tongue cancer surgery with regard to cancer outcomes. Demographic, surgical, and histology data from primary pT2 tongue cancers were recorded and evaluated through multivariate Cox regression for local recurrence (LR), disease-free survival (DFS), and overall survival (OS). A total of 166 patients with pT2 primary oral tongue cancer fulfilled the inclusion criteria; TOR was used in 95 patients and TMA in 71 patients. The minimum follow-up was 29 months. Group comparisons showed a significantly higher frequency of perineural spread (P=0.013) in the TMA group; a higher frequency of involved margins on initial resection was seen in TOR patients (P=0.010). Adjuvant postoperative radiotherapy was preferred in the TMA group, in line with the high pN positive status. Multivariate Cox regression showed significantly higher LR and lower DFS in the TOR group despite stratification of the major prognostic factors. The 5-year survival rate was reduced to 82.2% in the TOR group, while it remained constant at 93.0% in the TMA group. TMA provided superior local control and DFS compared to TOR in pT2 tongue cancers.

Cytoplasmic neuropilin 2 is associated with metastasis and a poor prognosis in early tongue cancer patients.

Neuropilin 2 (Nrp2) plays an important role in regulating lymphangiogenesis. Nrp2 expression in early tongue cancer was investigated to predict lymph node metastasis and the long-term prognosis. The relationships between clinicopathological variables of cT1-T2N0 tongue squamous cell carcinoma (SCC) and overexpression of Nrp2, vascular endothelial growth factor C (VEGFC), vascular endothelial growth factor receptor 3 (VEGFR3), and semaphorin 3F (Sema3F) were analyzed. Expression levels were compared using oral SCC cell lines. The Nrp2 gene was silenced to determine the impact of Nrp2. Cytoplasmic Nrp2 overexpression predicted regional metastasis with sensitivity and specificity of 90.3% and 42.1%, respectively. Cytoplasmic Nrp2 overexpression (P<0.001) and VEGFC overexpression (P=0.006) were significantly related to regional metastasis (Student t-test). However, only cytoplasmic Nrp2 overexpression was an independent prognostic factor for both disease-free survival (DFS; P=0.008) and overall survival (OS; P=0.016) (Cox regression); the risk of recurrence was 12-times higher (P=0.015) and risk of mortality was 8-times higher (P=0.016). Co-localization of Nrp2 and VEGFC was greater within the cytoplasm of aggressive cell lines (HN12 and RCa-T). Nrp2 plays a role in tumourigenesis; VEGFC supplementation cannot rescue the biological function of Nrp2 in Nrp2-depleted cell lines. Cytoplasmic Nrp2 overexpression is associated with decreased OS and DFS. Cytoplasmic Nrp2 overexpression may be a reliable diagnostic and prognostic marker for early tongue SCC.

Unusual presentation of abdominal Castleman's disease.

Castleman's disease is a rare lymphoproliferative disorder of uncertain origin. We report an unusual presentation of Castleman's disease in the transverse mesocolon that mimicked a vascular gastrointestinal stromal tumour and review the literature surrounding this peculiar entity.

A problem encapsulated: the rare peritoneal encapsulation syndrome.

Peritoneal encapsulation (PE) is a rare condition that has been described interchangeably with sclerosing encapsulated peritonitis as well as abdominal cocoon. We report an otherwise well 38-year-old man who presented with two episodes of intestinal obstruction about two months apart. Computed tomography (CT) of the abdomen showed characteristic features of the PE syndrome. Exploratory laparotomy was performed and small bowel was freed of adhesions and the encapsulation. Post-operative recovery was uneventful. PE is an extremely rare congenital condition in which there is abnormal return of the midgut loop to the abdominal cavity in the early stages of development. The small intestine is thus covered by the original dorsal mesentery, forming the characteristic accessory peritoneal sac. Management of cases is difficult as CT findings may not be characteristic and may only be diagnosed at laparotomy.

Outcome after laparoscopic versus open wedge resection for suspected gastric gastrointestinal stromal tumors: A matched-pair case-control study.

BACKGROUND: Laparoscopic resection of gastric gastrointestinal stromal tumors (GISTs) has been shown by several retrospective studies to be technically feasible and associated with favorable outcomes when compared to the open approach. This study aims to mitigate potential selection bias by performing a case control study of laparoscopic (LWR) versus open wedge resection (OWR) matched by resection type, location and tumor size. METHODS: We retrospectively identified 50 consecutive patients who underwent LWR for a suspected gastric GIST from a prospective database and matched this cohort with 50 patients who underwent OWR. RESULTS: There was no statistical difference between the key baseline clinicopathological features of patients' who underwent LWR versus OWR. Patients who underwent LWR had longer operating times [150 (range, 65-270) minutes vs 92.5 (25-200) minutes, P < .001] but decreased median blood loss [0 (0-300) ml vs 0 (0-1200) ml, P = .015], decreased frequency of intraoperative or postoperative blood transfusion [1 (2%) vs 8 (16%), P = .031], decreased median time to liquid diet [2 (0-5) vs 3 (1-7) days, P < .001], decreased median time to solid diet [3 (1-6) vs 5 (2-11) days, P < .001] and decreased postoperative stay [4 (2-10) vs 4.5 (3-17), P < .001] compared to OWR. There was no difference in oncological outcomes such as frequency of close margins (≤ 1 mm) and recurrence-free survival. CONCLUSION: This matched case-control study provides supporting evidence that LWR results in superior perioperative outcomes compared to OWR without compromising on oncological outcomes.

A rare life-threatening complication of migrated nitinol self-expanding metallic stent (Ultraflex).

The use of self-expanding metallic stents (SEMS) as esophageal endoprosthesis represents an advancement in the palliation of dysphagia from unresectable esophageal carcinoma. However, the problem of stent migration persists. Although most migrated stents have a benign outcome, complications do occur. Rare reports of intestinal obstruction have been confined to the stiff plastic and stainless-steel stents. We report the first case of intestinal obstruction secondary to the pliable Nitinol SEMS (Ultraflex) migration.

Early experience of limb salvage in critical leg ischaemia.

BACKGROUND: We report the retrospective review of 82 leg bypass grafts done in 79 patients who had critical leg ischaemia between May 1993 and November 1996. The mean age of the patients was 68 years (range 50 to 82). PATIENTS: There were 49 male and 35 female patients. Fifty-nine percent of the study population presented with gangrene, 33% had ischaemic ulceration and 58% had rest pain. Seventy-five percent of them were diabetics. Thirty-eight femoro-popliteal, 28 femoro-distal, 6 popliteal-distal, 5 pedal, 1 aorto-bifemoral, 3 axillo-bifemoral and 1 cross-over bypass grafts were done. RESULTS: The peri-operative mortality rate was 11.3% and 71% of patients were discharged with salvaged feet. Ninety percent of these legs were still viable 12 months after the operation.

Chronic haemodialysis with PTFE arterio-venous grafts.

BACKGROUND/AIM OF STUDY: End-stage renal failure (ESRF) patients requiring long-term haemodialysis need a durable vascular access. The arterio-venous fistula (AVF) with its long patency rate and low complication profile is usually the first choice procedure for vascular access creation. However when superficial veins are not suitable for AVF creation or have all been exhausted as a result of repeated AVF procedures, arterio-venous grafts (AVG) using polytetraflouroethylene (PTFE) to bridge arteries and veins is an alternative for provision of continued vascular access for haemodialysis. This study is a review of our experience in using PTFE AVGs for vascular access in patients requiring chronic haemodialysis. METHODS AND MATERIALS: A retrospective review was done on 92 grafts in 77 patients placed by 3 vascular access surgeons at the Singapore General Hospital from January 1989 to December 1994. RESULTS: There were 58 female and 19 male patients with a median age of 43 years (range 15-76 years). Twelve patients (16%) were diabetic and 6 patients (8%) had systemic lupus erythematosis requiring long-term steroids. Seventy-three percent of patients had up to 2 previous AVF creations before placement of AVG over the forearm (64%), upper arm (23%) or thigh (6.5%). Complications include graft infection (19), pseudoaneurysm formation (10), graft thrombosis (24), steal syndrome (1), venous congestion (1) and venous end stenosis (1). Diabetic status and long-term steroid therapy did not significantly increase the incidence of graft infection. The patency rates at 24 months and 36 months were 77% and 58% respectively. However serviceability rates were 61% at 2 years and 38% at 3 years mainly due to infective complications. CONCLUSION: PTFE AVGs offer reasonable patency and serviceability rates as a vascular access modality but in view of their complication profile, the native vein arteriovenous fistula should continue to be the first choice procedure for vascular access in patients requiring chronic haemodialysis.

The viability of liver graft for transplantation after prolonged warm ischaemia.

Maximum duration of warm ischaemia within which the liver graft is viable for transplantation remains undefined. Published data on porcine allogeneic liver transplantation (LTx) using non heart beating donors (NHBDs) are conflicting because technical details like the hepatic artery status, systemic heparinisation of donor animals and duration of rewarming were not addressed. We described a novel porcine model which simulate conditions of transplantation from NHBDs. The pigs were divided into three groups of 6 each. Groups I, II and III were subjected to 60, 90 and 120 minutes of warm ischaemia, respectively. Liver viability was assessed using four parameters: serum liver function tests (serum bilirubin and transaminase), dynamic liver function test i.e. the monoethylglycinexylidide (MEGX) formation test, morphological assessment and animal survival. All animals in groups I and II (90 minutes of warm ischaemia or less) survived but 50% of animals in group III died of massive liver failure. Given that rewarming period required in actual allogeneic LTx is about 60 minutes, the safe period for intervention in NHBDs is determined to be about 30 minutes. Allogeneic porcine LTx using NHBDs with 30 minutes of cardiac arrest were performed in 5 animals. All of them survived.

Radical resection of a Shamblin type III carotid body tumour without cerebro-neurological deficit: Improved technique with preoperative embolization and carotid stenting.

The surgical resection of a large unfavourable Shamblin type III carotid body tumour (CBT) can be very challenging technically, with many potential significant complications. Preoperative embolization aids in shrinking the lesion, reducing intraoperative blood loss, and improving visualization of the surgical field. Preoperative internal carotid artery (ICA) stenting aids in reinforcing the arterial wall, thereby providing a better dissection plane. A woman presented to our institution with a large right-sided CBT. Failure of the preoperative temporary balloon occlusion (TBO) test emphasized the importance of intraoperative preservation of the ipsilateral ICA. A combination of both preoperative embolization and carotid stenting allowed a less hazardous radical resection of the CBT. An almost bloodless surgical field permitted meticulous dissection, hence reducing the risk of intraoperative vascular and nerve injury. Embolization and carotid stenting prior to surgical resection should be considered in cases with bilateral CBT or a skull base orientated high CBT, and for those with intracranial extension and patients who have failed the TBO test.

Dermatofibrosarcoma protuberans on the right neck with superior vena cava syndrome: case report and literature review.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon dermal soft tissue tumour of intermediate malignancy. A 44-year-old man presented to the hospital with a large lesion on the right upper chest and neck. Despite eight previous surgical excisions, the tumour had continued to recur. Contrast-enhanced computed tomography showed recurrence of the tumour, associated with superior vena cava (SVC) syndrome. He declined radical surgical resection of the recurrent tumour, which may have required right upper limb amputation. Targeted therapy with sunitinib malate was therefore introduced. This case demonstrates the recurrent nature of DFSP and the association of this lesion on the upper chest/neck with SVC syndrome. Primary wide radical resection is essential for better local control and to avoid the development of SVC syndrome.

Treatment of scaphoid non-union with 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) vascularised graft.

INTRODUCTION: The purpose of this paper is to share the outcome of cases of scaphoid non-union treated with 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) vascularised graft at our institution, as well as to identify the possible factors for the failure of the procedure. METHODS: This was a retrospective review of 13 cases of scaphoid fracture non-union treated with 1,2 ICSRA vascularised bone grafting from October 2000 to March 2003. A clinical and radiological review was conducted. Linear regression was performed in order to identify the factors associated with a negative outcome. RESULTS: Out of the 13 patients with scaphoid non-union, ten (77 percent) had avascular necrosis of the proximal pole. The patients were followed up for a mean duration of 13 (range 3-28) months. Ten out of the 13 (77 percent) patients achieved union. CONCLUSION: Our results are comparable to those reported by other studies and indicate that avascular necrosis was associated with failure to achieve union.

Primary cutaneous cryptococcosis due to Cryptococcus gattii in Singapore.

Cryptococcosis is an invasive fungal infection that occurs worldwide. Infections caused by Cryptococcus (C.) neoformans are commonly associated with immunocompromised patients, while those caused by C. gattii predominantly affect immunocompetent hosts. However, the latter has also been increasingly reported in immunocompromised patients such as those with HIV. Cutaneous involvement by C. gattii in immunocompetent patients is a rare manifestation, with only a few cases reported worldwide. C. gattii infection has rarely been reported in Singapore, with all three reported cases presenting as meningitis in immunocompetent individuals. Its natural habitat is the Eucalyptus tree, which is common in Singapore. We report the case of a 37-year-old migrant worker who had primary cutaneous infection due to C. gattii after sustaining traumatic inoculation.