Unsuspected sphincter damage following childbirth revealed by anal endosonography.

Anal endosonography was performed in 62 consecutive patients with incontinence of flatus or faeces following obstetric trauma, and in 18 parous controls. Of the incontinent group, 90% had defects in the external sphincter, 65% in the internal sphincter and 44% disruption of the perineal body, compared with none of the controls. This triad of lesions is pathognomonic of obstetric trauma. Anal endosonography revealed a higher prevalence of sphincter damage than expected from anorectal physiology tests, and therefore has a role in screening patients following complicated or difficult deliveries.

The variation of position of the conus medullaris in an adult population. A magnetic resonance imaging study.

STUDY DESIGN: Sequential study of magnetic resonance images of the lumbar spine. OBJECTIVES: To determine the variation in position of the conus medullaris in a living adult population without spinal deformity. SUMMARY OF BACKGROUND DATA: Cadaveric studies have shown that the position of the conus medullaris in the adult most commonly is located at L1-L2. There have been several studies documenting the changing level of the conus throughout infancy and childhood, but there is no detailed study that documents the range of conus positions in a living adult population without spinal deformity. METHODS: The T1-weighted, midline, sagittal, spin-echo magnetic resonance imaging studies of 504 patients were assessed to identify the tip of the conus medullaris. This location was recorded in relation to the upper, middle, or lower third of the adjacent vertebral body or the adjacent intervertebral disc. RESULTS: The study group consisted of 231 men and 273 women with a mean age 46 years (range, 16-85 years). Most patients were being examined for low back pain. Patients with spinal deformity were excluded. The mean conus position was the lower third of L1 (range, middle third of T12 to upper third of L3). The variation in conus positions followed a normal distribution. No significant difference in conus position was seen between male and female patients or with increasing age. CONCLUSIONS: The distribution of conus location in a large adult population was shown to range from the middle third of T12 to the upper third of L3.

Ultrasound-guided needle biopsy of primary bone tumours.

Needle biopsy is an established technique for the histological diagnosis of bone tumours, usually guided by fluoroscopy or CT. Surface lesions and aggressive tumours which have extended through the cortex are also amenable to imaging with ultrasound (US). We have assessed the diagnostic accuracy of US-guided Trucut needle biopsy in a consecutive series of patients referred to a Bone Tumour Unit with suspected primary bone tumours. Of 144 patients (83 men, 61 women; mean age 34.7 years) referred over a period of two years, 63 were considered suitable for US-guided biopsy. This was based on the presence of a relatively large extraosseous component, seen typically in osteosarcoma and malignant round-cell tumours. The results of needle biopsy were compared with those of surgical biopsy. The diagnostic accuracy was 98.4%, with only a single failed biopsy. Thus, in a selected group of patients, US is a very reliable technique of guidance for percutaneous needle biopsy of bone tumours.

Endosonographic variations in the normal internal anal sphincter.

Anal endosonography provides clear images of the internal anal sphincter. Forty-two controls have been studied to establish a range for thickness and echogenicity of the normal internal sphincter, and any physical correlate for these observations. No relationship was found between the thickness of the internal anal sphincter and body weight, height or gender, but there was a significant correlation for thickness with age (p less than 0.001), the 95% confidence interval being 2.4-2.7 mm less than 55 years and 2.8-3.4 mm greater than 55 years. Hyperechogenicity of the internal sphincter was significantly associated with an age greater than 55 years (p less than 0.01) and a thickness greater than 2.8 mm (p less than 0.05). This has not been observed previously and suggests a histological change in the sphincter as it ages.

The value of lumbar spine MRI in the assessment of the pars interarticularis.

The aim of this study is to assess the ability of conventional lumbar spine magnetic resonance imaging (MRI) to demonstrate the pars interarticularis. The right and left L4 and L5 pars in 50 patients undergoing lumbar spine MRI for low back pain, with or without radiculopathy, were assessed and classified into four types. Based on their appearance, 59 (29.5%) were classified as normal (Type 1), 59 (29.5%) as hypointense (Type 2), 53 (26.5%) could not be demonstrated (Type 3) and 29 (14.5%) were thought to have defects (Type 4). The gold standard was set by the consensus opinion of two consultant musculoskeletal radiologists on the available plain radiographs of the lumbar spine. MRI was found to have a sensitivity of 57% to 86%, specificity of 81% to 82%, positive predictive value of 14% to 18% and negative predictive value of 97% to 99% for the diagnosis of a pars defect.

Pictorial review: ultrasonography of primary bone tumours.

We present our experience with the use of ultrasonography in the assessment of suspected primary or recurrent bone tumours of the appendicular skeleton and pelvis in 73 patients. Ultrasound can effectively assess the extraosseous component of malignant and aggressive benign lesions and those tumours arising from the surface of the bone. Periosteal reaction, cortical destruction, pathological fracture, matrix mineralization, fluid-fluid levels and involvement of the neurovascular bundle are all identified. Despite this, we could not identify any advantage of ultrasound compared to plain radiography or magnetic resonance imaging in diagnosis and local staging. However, ultrasound was found to be of great value in guiding percutaneous needle biopsy.

Confirmation of endosonographic detection of external anal sphincter defects by simultaneous electromyographic mapping.

Anal endosonography was performed in 13 consecutive patients with post-traumatic faecal incontinence. Thirteen acoustic defects in the external anal sphincter (two hyperechoic, four of mixed echogenicity and seven hypoechoic) were analysed electromyographically by locating under ultrasound guidance the tip of a concentric needle within the defect. The electromyographic activity in this zone was compared with ultrasonically normal muscle. Eleven of 13 sonographic defects showed no electrical activity on electromyography, there was one technical electromyography failure, and one defect was too deep to be reached by the electromyography needle. The electromyographic response was normal in each case within ultrasonically normal muscle. Anal endosonography is recommended as the initial investigation to locate defects, which may be confirmed electromyographically thereby limiting the number of painful needle insertions required for complete mapping of the external anal sphincter.

Sphincter injury after anal dilatation demonstrated by anal endosonography.

Anal dilatation is still used in the treatment of anal fissure and haemorrhoids. Using anorectal physiology and anal endosonography we have studied 12 men presenting with faecal incontinence following anal dilatation. Resting anal pressures were low, pudendal nerve latencies were normal; 11 men had a disrupted internal anal sphincter and in ten this was extensively fragmented. Three also had defects of the external anal sphincter. These findings demonstrate for the first time the nature of the structural injury which may be caused by anal dilatation.

Benign biopsies in the prevalent round of breast screening: a review of 137 cases.

In the first round of the National Health Service Breast Screening Programme, 35,533 women attended for screening at the two breast screening units served by St Bartholomew's Hospital. Further assessment was necessary in 2212 women (6.2%), of whom 412 (1%) subsequently underwent surgical biopsy. Of these 137 had benign lesions. The predominant mammographic abnormality leading to biopsy was microcalcification in 55, a mass in 48, parenchymal asymmetry in 18 and architectural distortion in 16. Histology revealed fibrocystic change in 66, fibroadenoma in 27, radial scar/complex sclerosing lesion in 23, atypical ductal hyperplasia only in eight, and a variety of unusual benign lesions in 13. In an attempt to determine criteria which would minimize unnecessary biopsy of benign lesions in future, the mammographic and cytological features of these benign lesions were reviewed and compared with the final histology. The most common diagnostic problems were clustered and variable microcalcification, the radial scar/complex sclerosing lesion, and mammographic features shown to be atypical hyperplasia on histology.