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Epidural fibrosis (EF) is a major cause of failed back surgery syndrome (FBSS), which induces disabling radiculopathy for which no effective medical treatment exists. Our understanding of the fibrosis mechanisms and our clinical and experimental results for the treatment of radiation-induced fibrosis prompted us to postulate that EF might respond to treatment with combined pentoxifylline (PTX)-tocopherol (Vit.E). 6 weeks after lumbar spine surgery, a 28-year-old man presented with recurrent left L5 sciatica without disc herniation on MRI in December 1993. From 1993 to 1997, he had unrelieved back and leg pain, which became increasingly resistant to intensive medical treatment and to a spinal cord stimulator, and confined him to bed as from December 1997. In 1998, a lumbar CT-scan showed an area of left L4-L5 EF measuring 12 mm x 12 mm, without disc herniation. From April 1998, oral PTX (800 mg day(-1)) and Vit.E (1000 IU day(-1)) were administered daily for 3.5 years and well tolerated. Clinical improvement began during the third month of treatment and continued until total regression of clinical symptoms April 2001. Lumbar MRI in November 2001 showed a surface area of residual EF half the size of the initial area. This is the first report to indicate that antifibrotic treatment using combined PTX-Vit.E may be of potential benefit in the treatment of post-operative EF. Additional studies are required to confirm this potential.

The delay in the appearance and the extent of a lesion induced by gamma-irradiation, in rabbit iliospinalis muscles, have been evaluated in vivo by MRI. The left side rabbit muscle was irradiated with an 192Ir sealed source at two skin surface doses: 40 Gy and 80 Gy. The progress of the lesion was followed on a long-term basis (12 months) by using T2 weighted spin echo imaging. The irradiation induced lesions were detected by MRI 22 weeks after irradiation for the 40 Gy group and 17 weeks for the 80 Gy group. The atrophy of the muscle and the extent of the lesion increased as a function of the dose at the skin surface. The threshold depth dose, corresponding to the deepest border of the lesion, was calculated by using the monoexponential attenuation law. The results gave the value of 20 +/- 7 Gy for the 40 Gy group and 16 +/- 3 Gy for the 80 Gy group.

Localized irradiation of the skin and subcutaneous tissues with large single doses of gamma-rays can induce delayed effects characterized by fibrosis which invades the irradiated tissues. In this study the depth of penetration of muscle fibrosis was measured in the pig 30 weeks after irradiation of the skin surface with single doses of 192Ir gamma-rays of 16-256 Gy. Irradiation was directed either to the outer side of the thigh or to the back, close to the mid-dorsal line. Fibrosis only developed in irradiated muscle after doses that induced moist desquamation of the skin in the acute phase of the reaction, i.e. after skin surface doses of 48-64 Gy. In skeletal muscles, the limit of fibrotic expansion was reached at a depth dose of 14 +/- 4 Gy (+/- SD) for skin surface doses exceeding 48 Gy.