Cost effectiveness of collagen crosslinking for progressive keratoconus in the UK NHS.

BACKGROUND: Keratoconus is a progressive degenerative corneal disorder of children and young adults that is traditionally managed by refractive error correction, with corneal transplantation reserved for the most severe cases. UVA collagen crosslinking is a novel procedure that aims to prevent disease progression, currently being considered for use in the UK NHS. We assess whether it might be a cost-effective alternative to standard management for patients with progressive keratoconus. METHODS: We constructed a Markov model in which we estimated disease progression from prospective follow-up studies, derived costs derived from the NHS National Tariff, and calculated utilities from linear regression models of visual acuity in the better-seeing eye. We performed deterministic and probabilistic sensitivity analyses to assess the impact of possible variations in the model parameters. RESULTS: Collagen crosslinking is cost effective compared with standard management at an incremental cost of £ 3174 per QALY in the base case. Deterministic sensitivity analysis shows that this could rise above £ 33,263 per QALY if the duration of treatment efficacy is limited to 5 years. Other model parameters are not decision significant. Collagen crosslinking is cost effective in 85% of simulations at a willingness-to-pay threshold of £ 30,000 per QALY. CONCLUSION: UVA collagen crosslinking is very likely to be cost effective, compared with standard management, for the treatment of progressive keratoconus. However, further research to explore its efficacy beyond 5 years is desirable.

Appendicular metastatic prostate cancer simulating osteosarcoma, Paget's disease, and Paget's sarcoma.

Skeletal metastases from prostate cancer is common and usually do not pose a diagnostic dilemma. This study reviews radiographic appearances of prostatic metastases to the appendicular skeleton in four patients where the appearances simulated osteosarcoma, Paget's disease and Paget's sarcoma. Prostatic metastases to long bones can produce appearances considered characteristic of other lesions and suggest misleading alternative diagnoses.

Tarsal tunnel syndrome and additional nerve lesions in the same limb.

Compression neuropathy in the lower extremity is common. The occurrence of more than one lesion of the nerve in the same limb is less frequent. Thirteen patients with 15 cases of tarsal tunnel syndrome associated with one or more additional lesions of the sciatic nerve or its branches of the same lower extremity are presented. Electrodiagnostic studies confirmed tarsal tunnel syndrome with conduction abnormalities at a number of locations along the sciatic, common peroneal, posterior tibial, or plantar nerves by mechanical impingement, metabolic axonal abnormality, or both. Seven of the 13 patients were treated with tarsal tunnel release. Six cases treated operatively improved significantly. Surgery on a previously operated foot or the existence of diabetes mellitus carried a fair prognosis. The association of back pain with or without previous surgery did not appear to affect the outcome of the tarsal tunnel release. No improvement in symptoms was apparent in the six unoperated patients during the period of the study. Multiple lesions of the nerves of a single extremity may account for the variable success rate of tarsal tunnel release.

Prevalence of scoliosis in neurofibromatosis.

Experience in a comprehensive, multispecialty neurofibromatosis clinic leads the authors to suggest that the association of spinal deformity with neurofibromatosis is less frequent than usually assumed. Previously reported statistics may be partly attributed to preselection of patients seen by spinal surgeons, and to the predominant referral of patients having severe manifestations of neurofibromatosis. A diagnosis of neurofibromatosis 1, based on National Institutes of Health criteria, is confirmed for two hundred twenty patients at the clinic. Twenty-three of these patients have structural scoliosis. Nine patients have idiopathic type curves, eight have dystrophic scoliosis, four have dystrophic kyphoscoliosis, and two have dystrophic lordoscoliosis. The authors believe that 10% is representative of the true prevalence of spinal deformity in an otherwise unselected cross section of neurofibromatosis patients.