SUMMARYThe study is based on a prospective survey of 200 necropsies, to determine the prevalence of colonic polyps and diverticula in Hong Kong. Adenomatous polyps were found in 34% of men and 19% of women. The corresponding figures for hyperplastic polyps were 22% and 15%. When compared with European countries having similar rates for colorectal cancer, the polyp pattern by type, prevalence, and distribution is very similar. For diverticula the prevalence rate in this study was only 5%; most of these were situated in the caecum. This is at marked variance to the European pattern.Adenomatous polyps have been established as the usual precursor of carcinomas of the large intestine. The incidence rates for colorectal carcinoma and the distribution pattern within the large intestine have been well documented for many countries, including Hong Kong,' 2 a population at intermediate risk.More recently, detailed information on the prevalence and distribution of adenomatous polyps has emerged from a number of prospective autopsy studies,31 but this information is still not available on a world wide basis. Methods NECROPSIESColons from 200 necropsies were collected at the Department of Pathology, Queen Mary Hospital, Hong Kong. This government hospital serves a population predominantly from lower socioeconomic groups. All cases were Chinese subjects. As far as possible the colons were collected consecutively from all patients over 10 years of age but excluding any with previous colonic surgery. A few intervening cases were not available for examination for a variety of reasons.The colons were collected by complete removal down to the pectinate line. They were opened, flushed with normal saline from a large tank, pinned out flat on polystyrene boards and fixed in 10% formalin for a minimum of 48 hours. Later, after

BackgroundThe aims are to present a case series of Twiddler’s syndrome in spinal cord stimulators with analysis of the possible mechanism of this syndrome and discuss how this phenomenon can be prevented.MethodData were collected retrospectively between 2007 and 2013 for all patients presenting with failure of spinal cord stimulators. The diagnostic criterion for Twiddler’s syndrome is radiological evidence of twisting of wires in the presence of failure of spinal cord stimulation.ResultsOur unit implants on average 110 spinal cord stimulators a year. Over the 5-year study period, all consecutive cases of spinal cord stimulation failure were studied. Three patients with Twiddler’s syndrome were identified. Presentation ranged from 4 to 228 weeks after implantation. Imaging revealed repeated rotations and twisting of the wires of the spinal cord stimulators leading to hardware failure.ConclusionsTo the best of our knowledge this is the first reported series of Twiddler’s syndrome with implantable pulse generators (IPGs) for spinal cord stimulation. Hardware failure is not uncommon in spinal cord stimulation. Awareness and identification of Twiddler’s syndrome may help prevent its occurrence and further revisions. This may be achieved by implanting the IPG in the lumbar region subcutaneously above the belt line. Psychological intervention may have a preventative role for those who are deemed at high risk of Twiddler’s syndrome from initial psychological screening.

Bullet injuries to the spine can cause significant damage to surrounding tissues and cause serious neurological sequelae. These cases are often associated with neurological deficits. We present a case of a gunshot injury to the spine with a migrating intrathecal bullet which subsequently developed neurological deficits. Initially, the patient did not exhibit any neurological symptoms when first assessed soon after the injury. Subsequently, the patient developed signs of neurological injury as a result of spinal intrathecal migration of the projectile.

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Aortorenal bypass is the preferred method of renal revascularization. However, a n alternative procedure is required in cases where anastomosis t o the diseased aorta cannot be safely or effectively performed. Harnessing the hepatic circulation was first described by Libertino in 1976'. Since Case reportA 15-year-old Chinese girl was admitted in November 1984, following a convulsive seizure. Blood pressure on admission was 180/120 on both In view of the poor control of her blood pressure by antihypertensives and the ischaemic changes of the right kidney, surgery was contemplated. Exploration in January 1985 revealed a rigid, fibrotic abdominal aorta below the origin of the renal artery. The segment of stenotic renal artery shown in the aortogram felt hard and nodular. Other vessels appeared normal.The diseased segment of renal artery was resected and a saphenous vein graft was inserted to join the end of the renal artery to the side of the hepatic artery (Figure 2). Histological examination revealed features of panarteritis and infiltration by lymphocytes, plasma cells and occasional giant cells, consistent with Takayasu's disease.Renal scan one month after surgery demonstrated satisfactory perfusion of the right kidney. Her renal function remained normal, as was the liver function. Eight months postoperatively, her blood pressure was maintained between 120/80 and 130/90 without any medication. DiscussionHypertension is now recognized as a common finding in Takayasu's arteritis. I t is commonly due t o partial obliteration of the renal artery orifices by hyperplastic intimal plaques, though other factors may be contributory. A number of procedures have been used t o treat renovascular hypertension, including patch plasty, resection and replantation, replacement, transaortic endarterectomy, and bypass grafting3. These procedures entail manipulation of the aorta which may itself be involved by the fibrosing and stenosing process. In the thoracoabdominal form of the disease, complex reconstruction employing a long prosthetic graft and one or more autogenous vein grafts is required4. The operation is time consuming, with considerable operative and postoperative risk. In the selected cases of coarctation of the lower abdominal aorta, hepatic circulation can be utilized as a n effective source of blood supply t o the right kidney, as depicted by the above case. The operation is relatively simple, carrying a low mortality and a high success rate. Its role is further enhanced by the fact that the hepatic artery is less frequently involved than the renal arteries in Takayasu's arteritis5.Other options are far from ideal. Even if the iliac arteries are not involved, autotransplantation of the kidney t o the pelvis carries the risk of disturbing the existing collateral circulation, and damage t o the kidney by longer ischaemic time. Perfusion may soon be insufficient from a part of the arterial tree distal to a progressing, stenotic lesion6. O n the other hand, the tight and rigid stenosis would not readily yield t o per...