Assessing bone density on MRI: comparison between routine MRI sequences and DEXA scans

PURPOSE

Magnetic Resonance Imaging (MRI) is frequently utilised to aid in the comprehensive assessment of back pain, while dual-energy x-ray absorptiometry (DEXA) is the gold standard test for the assessment of bone density. Assessing bone density on MRI could reduce costs and avoid exposing patients to ionising radiation. The aim of this paper is to investigate whether the relative signal intensity of vertebral bodies compared to other structures can detect osteoporosis on MRI.

METHODS

100 patients that had undergone both a lumbar spine MRI and a DEXA scan were identified. The T1 and T2 signal intensity of L1-L4 vertebral bodies (VB), cerebro-spinal fluid (CSF), and psoas muscle were measured within a 1-cm2 region of interest (ROI), and the signal intensity ratios were calculated. The ratios were stratified as normal, osteopenic, or osteoporotic based on DEXA T-scores.

RESULTS

The T1 VB /T1 CSF ratio was significantly higher in the osteoporotic group than the normal and osteopenic groups (p < 0.001). The T1 VB /T1 CSF ratio had excellent discrimination (AUC = 0.841) for the presence of osteoporosis. The Pearson correlation coefficient between the DEXA T-score and the T1 VB/T1 CSF ratio was -0.474 (p < 0.001). The intra-observer (ICC = 0.910, 95% CI = 0.757-0.966) and inter-observer reliability (ICC = 0.927, 95% CI = 0.824-0.970) were excellent. In our cohort, a T1 VB / T1 CSF ratio of greater than 4 is 66.7% sensitive but 90.0% specific for the presence of osteoporosis.

CONCLUSION

A high T1 VB/T1 CSF ratio suggests osteoporosis on MRI. Prospective validation is needed to confirm these findings.

Genetic analysis for semen quality traits in buffalo bulls

This study was attempted to estimate the genetic parameters of semen quality traits in buffalo bulls. The study data consisted of 10975 ejaculates from 45 Murrah buffalo bulls (aged 24-72 months) used for breeding program during year 2010 to 2020. Semen quality traits (ejaculate volume, concentration of sperm, mass activity, initial and post-thaw motility, number of sperms per ejaculate, motile sperm number and discard rates) were studied. It was observed that average ejaculate volume was 2.82 ± 1.45 mL with mean concentration of 1040.12 ± 523.26 million/mL. Higher heritability was observed for number of sperms per ejaculate, number of motile sperm and sperm concentration. Significant phenotypic correlation was obtained between volume and number of sperms per ejaculate as well as volume and number of motile sperms. Likewise, significant phenotypic correlation was evident between sperm concentration with sperm number per ejaculate. Highest phenotypic correlation was obtained between sperm count per ejaculate and motile sperm count. Estimated genetic trends showed significant change in volume and motile sperm number. In conclusion, this study ascertains that genetic parameters of semen traits can be considered during the selection of buffalo bulls in breeding program.

The impact of blood conservation techniques on transfusion requirements for posterior adolescent idiopathic scoliosis corrections: do we need a routine cross-match for the operation?

PURPOSE

Various strategies are utilised to reduce blood loss and allogenic blood transfusion for posterior instrumented correction of Adolescent Idiopathic Scoliosis (AIS). The aim of this study was to evaluate post-operative blood transfusion requirements to determine whether routine cross matching of blood is essential.

METHODS

This is a prospective case series of 84 patients who underwent posterior correction of AIS between September 2016 and March 2018. We reviewed demographic, operative, radiological data and transfusion requirements. Results of transfusion requirements in 44 patients who underwent Ponte osteotomies (F:M = 36:8; mean age 14.8 years) were compared with 40 patients (F:M = 9:31; mean age 14.4 years) who did not and provided the control group. A transfusion trigger of 80 mg/dl with clinical caveats was utilised. Cross matching and procurement costs of allogenic blood/unit were ascertained.

RESULTS

Five patients required postoperative blood transfusion on days 2 or 3. Anaesthetic time (p = 0.0003) and preoperative Cobb angle (p = 0.0166) were significant variables between both groups and post-operative Hb (p = 0.0084) and number of levels fused (p = 0.0312) being significant in patients requiring transfusion. Unutilised units on the day of the operation incurred £30,030 (£380/patient or £154/unit) in operational costs.

CONCLUSION

Our audit demonstrates that transfusion on the day of the operation was not required. We recommend that routine crossmatching is not essential for primary posterior correction for AIS with blood conservation techniques. Blood grouping with availability of urgent blood is sufficient at the onset of operation. This has financial implications and cost savings.

LEVELS OF EVIDENCE

III.

102 Age-related differences in seminal parameters and expression of fertility marker genes in Marwari stallion

The objective of the present study was to observe age-related differences in seminal parameters and expression of fertility marker genes in Marwari stallions. Semen was collected from 9 Marwari stallions (6 ejaculates per stallion) of 3 different age groups (2 to 4 years, GI; 4 to 6 years, GII; and &gt;6 years, GIII) twice a week using an artificial vagina by allowing the stallions to mount a mare. The collected ejaculate was divided into 2 parts. Part A was used for evaluation of various seminal parameters (colour, consistency, total volume, gel volume, gel-free volume, pH, progressive sperm motility, sperm concentration, sperm viability, total sperm morphological abnormalities, plasma membrane integrity, acrosomal integrity, and DNA integrity). Part B was centrifuged to obtain the sperm pellet for DNA extraction. Six fertility-related marker genes (SPATA1, SP17, PLCz, CRISP3, UBB, and PRM1) were examined in the spermatozoa DNA using PCR. Expression levels of these genes were also studied using quantitative real-time PCR. Data obtained were analysed statistically by one-way or two-way analysis of variance using the SPSS computer program (version 20.0; IBM Corp.). No significant difference was observed among the GI, GII, and GIII stallions for seminal parameters, except mean sperm concentration, which was lowest in 2- to 4-year-old stallions (146.06±11.50 million mL−1), intermediate in stallions &gt;6 years old (182.03±8.51 million mL−1), and highest in stallions of 4 to 6 years (270.92±9.12 million mL−1; P&lt;0.01). The study demonstrated that all six fertility-related genes showed differential expression in stallions from the GI, GII, and GIII groups. In addition, expression levels of the same genes varied across individuals. Expression of SPATA1, SP17, PLCz, CRISP3, UBB, and PRM1 genes was reduced in stallions below 4 years of age compared with older stallions. This result suggests that expression of these genes increases with age, although possibly only up to a certain age. We inferred that stallions around 4–6 years of age can be considered optimum to use for breeding purposes, provided seminal parameters are normal.

107 Administration of antioxidants improves serum total antioxidant capacity, testosterone, and seminal quality of Magra rams

Oxidative stress is one of the most important factors responsible for poor quality of semen, and it is defined as an imbalance between the formation of reactive oxygen species (ROS, including hydroxyl radicals, superoxide anions, and hydrogen peroxide) and antioxidant capacity of semen. Antioxidants act as a powerful defence system against ROS attack in sperm cells by decreasing oxidative stress and they improve semen quality, which could be useful in the management of male infertility. Magra is a dual-purpose (wool and meat) hardy sheep breed that originated in the eastern and southern parts of the Bikaner district of Rajasthan, India. The present study evaluated the effects of the administration of vitamin E with selenium or vitamin C on serum antioxidants, testosterone, and seminal quality of Magra rams. Twenty-one Magra rams, aged between 1.5 and 2.5 years, were randomly assigned to treatment at weekly intervals with administration of either 1mL of vitamin E (tocopherol, 50mg mL−1) and selenium (1.5mg sodium selenite; n=7; VES), 8mL of vitamin C (250mg mL−1 sodium ascorbate; n=7; VC), or 1mL of saline (n=7; control) subcutaneously for 5 consecutive weeks. After the fourth week, semen and blood were collected twice a week for 5 consecutive weeks and assayed for seminal quality parameters, serum testosterone, and serum antioxidants. Data obtained were analysed statistically using te SPSS software (version 25.0; IBM Corp.). Mean values were compared using Duncan’s multiple range test. The semen parameters sperm motility, sperm concentration, live sperm percentage, and% HOST (hypo-osmotic swelling test)-positive sperm were significantly elevated, whereas reaction time and percentage of abnormal sperm were lower in both the treated groups compared with controls (P&lt;0.05). Seminal pH declined significantly in the VES group (P&lt;0.05), whereas it was not different between the VC and control groups of rams (P&gt;0.05). Glutathione peroxidase, superoxide dismutase, and total antioxidant capacity concentrations were higher in serum and seminal plasma of treated rams (P&lt;0.05). Serum testosterone concentrations were significantly elevated in VES and VC groups (P&lt;0.05). We concluded that the administration of vitamin E and selenium or vitamin C improves the serum testosterone production and seminal quality of rams.

144 Serum testosterone profile in Marwari stallions and its relationship with testicular parameters, semen characteristics, reaction time, stallion age, bodyweight, and height

The present study investigated the serum testosterone profile of Marwari stallions before and after exposure to a mare and the relationship of serum testosterone profile with scrotal circumference, semen characteristics, reaction time, stallion age, bodyweight, and height. Marwari stallions (n=9) of three age groups (2-4 years, n=3; 4-6 years, n=3; and 6+ years, n=3) were used in the study. Scrotal circumference, height, and bodyweight of each of the stallions were measured. Semen was collected from each stallion twice per week in the early-morning hours using an artificial vagina and a mare in oestrus. Six ejaculates were collected from each stallion for evaluation of various seminal parameters (semen volume, sperm concentration, and progressive sperm motility). Reaction time for each stallion was also recorded. At every alternate semen collection (first, third, and fifth collections), blood samples were taken 15min before exposure to the mare and just before the semen collection for serum testosterone hormone assay using a horse testosterone enzyme-linked immunosorbent assay kit. The data obtained were analysed statistically using SPSS ver. 20.0 (IBM Corp.). The results showed that mean testosterone concentration was significantly different (P ≤ 0.01) among the stallions and was significantly lower (P ≤ 0.01) in the stallions below 4 years of age. No significant difference in testosterone level was observed before and after exposure to a mare. A positive correlation was detected between testosterone and both scrotal circumference (P ≤ 0.05) and sperm concentration (P ≤ 0.05), whereas a negative correlation was observed with reaction time (P ≤ 0.01). It was concluded that exposure to a mare does not change the testosterone level in stallion blood and that there is a relationship of serum testosterone concentration with scrotal circumference, sperm concentration, reaction time, and age but not with height and bodyweight.

[Corneal cell therapy-an overview]

In recent years, the cultivation and expansion of primary corneal cells has made significant progress. The transplantation of cultured limbal epithelial cells represents a successful and established treatment of the ocular surface. Cultivated corneal endothelial cells are undergoing a clinical trial in Japan. Stromal keratocytes can now be expanded in vitro. A wide range of stem cell sources is being tested in vitro and animal models for their possible application in corneal cell therapy. This article gives an overview of recent advancements and prevailing limitations for the use of different cell sources in the therapy of corneal disease.

Dynamic change in natural killer cell type in the human ocular mucosa in situ as means of immune evasion by adenovirus infection

The most severe form of virus-induced inflammation at the ocular surface is epidemic keratoconjunctivitis (EKC), often caused by group D human adenoviruses (HAdVs). We investigated the dynamics and mechanisms of changes in natural killer (NK) cell types in the human ocular mucosal surface in situ over the course of infection. In the acute phase of infection, the mature CD56(dim)NK cells that comprise a major subpopulation in the normal human conjunctiva are replaced by CD56(bright)NK cells recruited to the ocular surface by chemokines produced by the infected epithelium, and NKG2A-expressing CD56(dim) and CD56(bright) NK cells become the major subpopulations in severe inflammation. These NK cells attracted to the mucosal surface are however incapable of mounting a strong antiviral response because of upregulation of the inhibitory ligand human leukocyte antigen-E (HLA-E) on infected epithelium. Furthermore, group D HAdVs downregulate ligands for activating NK cell receptors, thus rendering even the mature NKG2A(-)NK cells unresponsive, an immune-escape mechanism distinct from other adenoviruses. Our findings imply that the EKC-causing group D HAdVs utilize these multiple pathways to inhibit antiviral NK cell responses in the initial stages of the infection.

Risk factors for contact lens-related microbial keratitis in Singapore

PURPOSE

To investigate independent risk factors for contact lens-related microbial keratitis in Singapore and estimate their impact on disease load.

METHODS

Cases were contact lens wearers presenting to Singapore National Eye Centre with microbial keratitis between 2008 and 2010. Community contact lens wearers were recruited as controls. All wearers completed a previously validated questionnaire describing contact lens wear history, hygiene and compliance habits, and demographics. Risk factors significant in univariate analysis (P<0.2) were evaluated in a multivariate model.

RESULTS

In all, 58 cases of microbial keratitis and 152 contemporaneous controls were identified. When controlling for other variables, Chinese had a 7 × lower risk compared with other races (95% CI: 2.3-21.3, P=0.001). Those aged between 25 and 44 years were at 3 × increased risk compared with younger wearers (95% CI: 1.1-9.6, P=0.04). Occasional overnight contact lens wear (less often than one night per week) was associated with a 4 × higher risk (95% CI: 1.2-15.4, P=0.03) compared with daily use. Not washing hands before handling was associated with a 13 × increased risk (95% CI: 1.9-84.8, P=0.008). Use of multipurpose solution A carried a 16 × higher risk compared with hydrogen peroxide (95% CI: 1.5-174.0, P=0.02). The combined PAR% for modifiable risk factors (occasional overnight wear, not washing of hands, and MPS A) was 82%.

CONCLUSIONS

Consistent with previous findings, independent risk factors for contact lens-related microbial keratitis include poor hand hygiene, occasional overnight wear, and type of lens care solution. Prolonged overnight or extended contact lens use was infrequent in this population.

Comparison of intra-ocular pressure changes with liquid or flat applanation interfaces in a femtosecond laser platform

Cataract surgery is the most common surgical procedure and femtosecond laser assisted cataract surgery (FLACS) has gained increased popularity. FLACS requires the application of a suction device to stabilize the laser head and focus the laser beam accurately. This may cause a significant escalation in intra-ocular pressure (IOP), which poses potential risks for patients undergoing cataract surgery. In this study we aimed to assess the effect of the Ziemer LDV Z8 femtosecond cataract machine on IOP. We demonstrated through a porcine model that IOP was significantly higher with a flat interface but could be abrogated by reducing surgical compression and vacuum. Pressure was lower with a liquid interface, and further altering angulation of the laser arm could reduce the IOP to 36 mmHg. A pilot series in patients showed comparable pressure rises with the porcine model (30 mmHg). These strategies may improve the safety profile in patients vulnerable to high pressure when employing FLACS with the Ziemer LDV Z8.

Surgical management and genetic analysis of a Chinese family with the S171P mutation in the UBIAD1 gene, the gene for Schnyder corneal dystrophy

BACKGROUND

To describe the underlying molecular genetic basis, surgical management and phenotypic variation of Schnyder corneal dystrophy (SCD) identified in a four-generation Chinese family.

METHODS

This is an interventional case series of 13 members from a non-consanguineous Chinese family. All patients underwent complete ophthalmological examination and slit-lamp photography. Subsequent corneal transplantations were performed (n = 3). Blood samples were taken for DNA extraction and subsequent genetic analysis.

RESULTS

Genotyping indicated linkage to the locus at chromosome 1p36. Screening of the UBIAD1 gene identified a highly conserved mutation, Ser171Pro. Phenotypic variation in this large pedigree is similar to that seen in Caucasian patients. Surgical management of patients with anterior lamellar keratoplasty and deep anterior lamellar keratoplasty showed good visual outcomes.

CONCLUSIONS

The S171P mutation is described for the first time in a Chinese family. This is the largest non-Caucasian pedigree described with SCD. Visual rehabilitation may be performed successfully with lamellar surgical procedures as opposed to full-thickness corneal grafts.

The variation in transparency of amniotic membrane used in ocular surface regeneration

BACKGROUND/AIMS

Scant consideration has been given to the variation in structure of the human amniotic membrane (AM) at source or to the significance such differences might have on its clinical transparency. Therefore, we applied our experience of quantifying corneal transparency to AM.

METHODS

Following elective caesarean, AM from areas of the fetal sac distal and proximal (ie, adjacent) to the placenta was compared with freeze-dried AM. The transmission of light through the AM samples was quantified spectrophotometrically; also, tissue thickness was measured by light microscopy and refractive index by refractometry.

RESULTS

Freeze-dried and freeze-thawed AM samples distal and proximal to the placenta differed significantly in thickness, percentage transmission of visible light and refractive index. The thinnest tissue (freeze-dried AM) had the highest transmission spectra. The thickest tissue (freeze-thawed AM proximal to the placenta) had the highest refractive index. Using the direct summation of fields method to predict transparency from an equivalent thickness of corneal tissue, AM was found to be up to 85% as transparent as human cornea.

CONCLUSION

When preparing AM for ocular surface reconstruction within the visual field, consideration should be given to its original location from within the fetal sac and its method of preservation, as either can influence corneal transparency.

Surgical interventions for age-related cataract

BACKGROUND

Cataract accounts for 50% of blindness globally and remains the leading cause of visual impairment in all regions of the world, despite improvements in surgical outcomes (WHO 2005). This number is expected to rise due to an aging population and increase in life expectancy. Although cataracts are not preventable, their surgical treatment is one of the most cost-effective interventions in healthcare.

OBJECTIVES

To compare the effects of different surgical interventions for age-related cataract.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005, the reference lists of identified trials and we contacted investigators and experts in the field for details of published and unpublished trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTS).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and discrepancies were resolved by discussion. Where appropriate, risk ratios, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies.

MAIN RESULTS

We identified 17 trials that randomised a total of 9627 people. Phacoemulsification gave a better visual outcome than extracapsular surgery but similar average cost per procedure in Europe but not in poorer countries. Extracapsular surgery with posterior chamber lens implant and ICCE with or without an anterior chamber intraocular lens (IOL) implant gave acceptable visual outcomes but extracapsular surgery had less complications. Manual small incision surgery provides better visual outcome than ECCE but slightly inferior unaided visual acuity compared to phacoemulsification.

AUTHORS' CONCLUSIONS

This review provides evidence from seven RCTs that phacoemulsification gives a better outcome than ECCE with sutures. We also found evidence that ECCE with a posterior chamber lens implant provides better visual outcome than ICCE with aphakic glasses. The long term effect of posterior capsular opacification (PCO) needs to be assessed in larger populations. The data also suggests that ICCE with an anterior chamber lens implant is an effective alternative to ICCE with aphakic glasses, with similar safety. Phacoemulsification provides the best visual outcomes but will only be accessible to the poorer countries if the cost of phacoemulsification and foldable IOLs decrease. Manual small incision cataract surgery provides early visual rehabilitation and comparable visual outcome to PHACO. It has better visual outcomes than ECCE and can be used in any clinic that is currently carrying out ECCE with IOL. Further research from developing regions are needed to compare the cost and longer term outcomes of these procedures e.g. PCO and corneal endothelial cell damage.

Protein C levels in patients with Legg-Calve-Perthes disease: is it a true deficiency?

A hyper-coagulable state due to protein C deficiency has been postulated to be the cause of avascular necrosis of the capital femoral physes in Legg-Calve-Perthes disease (LCPD). In order to test this hypothesis, plasma protein C levels were analyzed from 51 unselected cases of LCPD. These were compared with a control group. Our findings showed that the levels were less than the mean for age in 38 (74.5%) of the cases, though were within the normal range. We conclude that clinical thrombosis could be triggered off in these susceptible individuals by prothrombotic insults such as passive smoking, ultimately leading to LCPD.

Hydroxyapatite promotes superior keratocyte adhesion and proliferation in comparison with current keratoprosthesis skirt materials

AIM

Published clinical series suggest the osteoodontokeratoprosthesis (OOKP) may have a lower extrusion rate than current synthetic keratoprostheses. The OOKP is anchored in the eye wall by autologous tooth. The authors' aim was to compare adhesion, proliferation, and morphology for telomerase transformed keratocytes seeded on calcium hydroxyapatite (the principal mineral constituent of tooth) and materials used in the anchoring elements of commercially available synthetic keratoprostheses.

METHODS

Test materials were hydroxyapatite, polytetrafluoroethylene (PTFE), polyhydroxyethyl methacrylate (HEMA), and glass (control). Cell adhesion and viability were quantified at 4 hours, 24 hours, and 1 week using a calcein-AM/EthD-1 viability/cytotoxicity assay. Focal contact expression and cytoskeletal organisation were studied at 24 hours by confocal microscopy with immunoflourescent labelling. Further studies of cell morphology were performed using light and scanning electron microscopy.

RESULTS

Live cell counts were significantly greater on hydroxyapatite surfaces at each time point (p<0.04). Dead cell counts were significantly higher for PTFE at 7 days (p<0.002). ss(1) integrin expression was highest on hydroxyapatite. Adhesion structures were well expressed in flat, spread out keratocytes on both HA and glass. Keratocytes tended to be thinner and spindle shaped on PTFE. The relatively few keratocytes visible on HEMA test surfaces were rounded and poorly adherent.

CONCLUSIONS

Keratocyte adhesion, spreading, and viability on hydroxyapatite test surfaces is superior to that seen on PTFE and HEMA. Improving the initial cell adhesion environment in the skirt element of keratoprostheses may enhance tissue integration and reduce device failure rates.

Optic disc duplication or coloboma?

AIM

To describe lesions resembling optic disc duplication and highlight their unusual visual fields. The authors also report the first case of pseudo-duplication of the optic disc with overlying retinal nerve fibre layer.

METHODS

Retrospective, non-comparative review of case notes. Humphrey visual fields and OCT-3 imaging were performed.

RESULTS

All 11 cases represented peripapillary chorioretinal coloboma, some of which lie superior to the optic disc. A double blind spot or superior hemifield defects can be demonstrated by automated visual field testing.

CONCLUSION

Clinical examination and identification of bridging retinal vessels from the true optic disc to the second pseudo disc can usually avoid unnecessary invasive and non-invasive investigations.

Weight-bearing radiographs in thoracolumbar fractures: do they influence management?

STUDY DESIGN

Prospective observational study.

OBJECTIVE

Our objective was to compare supine and erect (weight-bearing) radiographs in patients with thoracolumbar fractures without a neurologic deficit and to determine whether the erect radiographs alter the deformity and the management plan.

SUMMARY OF BACKGROUND DATA

Nonoperative treatment for thoracolumbar fracture without a neurologic deficit is safe and effective. There are some guidelines in the literature that provide objective standards to identify the patients that are suitable for nonoperative treatment. These guidelines are based on measurements on supine radiographs. The role of weight-bearing radiographs in influencing the management plan of these injuries has not been explored.

METHODS

Fractures between T11 and L2 in 28 patients were considered suitable for nonoperative treatment initially. Radiographic measurements included anterior and posterior vertebral body heights, interpedicular distance, and the Cobb angle on the supine and erect radiographs. A change in the treatment from the initial nonoperative management plan, based on the radiographic findings, was recorded.

RESULTS

Mean supine Cobb angle of 11 degrees increased to 18 degrees on weight-bearing films. The mean anterior vertebral compression increased from 34% to 46%. No change was noted between the posterior vertebral heights and the interpedicular distance. Seven of the 28 patients were subjected to surgical stabilization based on these findings.

CONCLUSION

Performing erect radiographs in patients with thoracolumbar fractures without a neurologic deficit provides additional information and did alter the management plan in a significant proportion (25%) of our patients.

Venous leg ulcers after hip replacement

Venous ulceration is a chronic disabling complication of deep-vein thrombosis. The aim of this study was to estimate the incidence of venous leg ulcers five years or more after total hip replacement (THR) and to investigate some of the clinical features associated with their development.

We carried out a postal survey of all patients who had undergone a THR 5 to 12 years previously. Replies from 816 patients showed that 66 (8.1%) had a history of leg ulcers. The prevalence of active ulceration was 2.6% and 43 patients (5.3%) reported developing ulceration since their hip replacement. A clinical review determined that 31 (3.8%) of these were true venous ulcers. The ulcers occurred more commonly on the operated side and developed at a mean of 5.8 years (18 months to 12 years) after the first arthroplasty. A mean of 1.9 arthroplasties (1 to 5) (primary and revision) were carried out before the ulcers appeared. The overall incidence of ulcers was similar to that in the general population.

The sclera, the prion, and the ophthalmologist

Prions have emerged in the past 5 years as serious transmissible infective agents. Ocular tissue transplantation has come under scrutiny after potential infected tissue was transplanted into healthy patients. In this review we examine the evidence for the risk of transmission of prions after scleral transplantation and explore alternative materials that may be used in ocular surgery.

Tuberculosis of the thoracic spine

In spinal tuberculosis MRI can clearly demonstrate combinations of anterior and posterior lesions as well as pedicular involvement. We propose a classification system, using information provided by MRI, to help to plan the appropriate surgical treatment for patients with thoracic spinal tuberculosis. We describe a series of 47 patients, divided into four groups, based on the surgical protocol used in the management. Group A consisted of patients with anterior lesions which were stable with no kyphotic deformity, and were treated with anterior debridement and strut grafting. Group B comprised patients with global lesions, kyphosis and instability who were treated with posterior instrumentation using a closed-loop rectangle with sublaminar wires, and by anterior strut grafting. Group C were patients with anterior or global lesions as in the previous groups, but who were at a high risk for transthoracic surgery because of medical and possible anaesthetic complications. These patients had a global decompression of the cord posteriorly, the anterior portion of the cord being approached through a transpedicular route. Posterior instrumentation was with a closed-loop rectangle held by sublaminar wires. Group D comprised patients with isolated posterior lesions which required posterior decompression only.

An understanding of the extent of vertebral destruction can be obtained from MRI studies. This information can be used to plan appropriate surgery.

Tuberculosis of the thoracic spine. A classification based on the selection of surgical strategies

In spinal tuberculosis MRI can clearly demonstrate combinations of anterior and posterior lesions as well as pedicular involvement. We propose a classification system, using information provided by MRI, to help to plan the appropriate surgical treatment for patients with thoracic spinal tuberculosis. We describe a series of 47 patients, divided into four groups, based on the surgical protocol used in the management. Group A consisted of patients with anterior lesions which were stable with no kyphotic deformity, and were treated with anterior debridement and strut grafting. Group B comprised patients with global lesions, kyphosis and instability who were treated with posterior instrumentation using a closed-loop rectangle with sublaminar wires, and by anterior strut grafting. Group C were patients with anterior or global lesions as in the previous groups, but who were at a high risk for transthoracic surgery because of medical and possible anaesthetic complications. These patients had a global decompression of the cord posteriorly, the anterior portion of the cord being approached through a transpedicular route. Posterior instrumentation was with a closed-loop rectangle held by sublaminar wires. Group D comprised patients with isolated posterior lesions which required posterior decompression only. An understanding of the extent of vertebral destruction can be obtained from MRI studies. This information can be used to plan appropriate surgery.

Latent proliferative sickle cell retinopathy in sickle cell trait

PURPOSE

To describe a patient with sickle cell trait who developed latent proliferative sickle cell retinopathy after mild blunt trauma.

METHOD

Case Report. A 20-year-old man with unilateral Stage 3 sickle retinopathy associated with an ischaemic ridge presenting three years after the initial mild blunt ocular trauma.

RESULTS

Fundus examination of the left eye showed an ischaemic ridge delineating avascular from vascular retina. Fluorescein angiography of the left eye showed an avascular peripheral retina and multiple sea fan neovascularization. Blood studies showed him to be Hb AS.

CONCLUSIONS

In our patient the proliferative changes were the result of his initial mild trauma associated with an increase in the intraocular pressure. The latent development of the sea-fan neovascularization associated with an ischaemic ridge is unusual. Advice about potential complications to patients with Hb AS after ocular trauma is advocated.

Recombinant tissue plasminogen activator following paediatric cataract surgery

BACKGROUND

The use of recombinant tissue plasminogen activator (r-TPA) has been advocated in the treatment of postsurgical fibrinous membrane formation following cataract surgery in adults. Its use in paediatric cases is not well documented.

METHOD

A retrospective review of paediatric cataract extractions performed at Moorfields Eye Hospital between 1 January 1997 and 4 April 1999 was carried out.

RESULTS

Cataract extractions were performed in 37 patients, 22 in males 15 in females. Four (9.2%) underwent intracameral injection of 25 microg r-TPA. They were all females of Afro-Caribbean origin. The time to injection varied from 4-14 days, mean 7.2 days. Complete resolution of the fibrinous membrane was seen in all cases. There were no complications by the 3 month follow up.

CONCLUSION

r-TPA may be used safely and effectively at a dose of 25 microg for the treatment of severe fibrinous membranes following paediatric cataract extraction. It aided the visual recovery of the children and also allowed a reduced regimen of topical steroid therapy to be used postoperatively.

Unusual radiological appearance of a skull osteoma

A 24-year-old woman presented with a 7-week history of headache and left frontal scalp swelling. A plain radiograph and CT demonstrated a 2-cm lytic lesion in the frontal bone which was excised via craniotomy. Histology showed this to be an osteoma. Osteomas very rarely, if ever, appear as lytic lesions. The differential and radiological diagnoses are discussed.

Sudden right-sided hemiparesis in a middle-aged woman

Images

An unusual cause of acute labyrinthine failure

We report a case of a 40-year-old man presenting with acute vertigo and deafness. Computed tomography (CT) scanning at initial presentation was normal. However, one year later he developed numbness on the right side of his face and examination revealed fifth, seventh and eighth cranial nerve palsies as well as cerebellar dysfunction. Magnetic resonance imaging (MRI) demonstrated a cerebellopontine angle lesion. He underwent near total excision followed by neuro-axis irradiation. The main mass of the tumour projected into the cerebellopontine angle. Histology showed this to be a medulloblastoma. All features of this case are unusual; hence we discuss the pathogenesis and management of this very rare tumour.