Decision to operate for lumbar nerve root compression is usually based on the clinical findings and MRI scan evidence of nerve root compression. Decision-making is difficult in the small subset of patients with atypical pain, pain in the groin, buttock or thigh with L5 and S1 nerve root compression, as evident on the MRI scan. We retrospectively studied 125- diagnostic nerve root injections; of which there were 12 patients who had pain in the groin, thigh or buttock and their MRI scans were reported as nerve root (11 L5 & 1 S1) compression by the radiologist independently. All these 12 patients were subjected to injection of the affected nerve root with bupivacaine and methylprednisolone under the guidance of image intensifier. Of these 5 (42%) of them had temporary relief of the symptoms; and all of them underwent surgical decompression of the affected nerve root. They were followed for an average of 12 months with satisfactory results. This demonstrates the importance of nerve root injections as a diagnostic tool in patients with atypical symptoms with nerve root compression as seen on the MRI scan.

For meniscal allograft transplantation, cell viability and metabolic activity are desirable. The various modalities of preserving the menisci described in the literature include, deep freezing, gluteraldehyde, lyophillisation and cryopreservation. Since formalin in low concentrations is a proven and inexpensive method of tissue preservstion, we attempted to analyse the viability of fibrochondrocytes in the meniscal tissue preserved in three different concentrations of formalin. Twenty-four rabbit menisci were assessed, three groups of 6 menisci each were preserved in 0.25%, 1%, 5% formalin for a period of three weeks; fourth group of 6 fresh menisci were used as controls. The uptake of Na235SO4 and LDH (lactate de-hydrogenase) were analysed for indirect evidence of cell viability. Menisci preserved in 0.25% of formaldehyde showed statistically similar Na235SO4 uptake and LDH activity as the controls; reflecting a similarity in the level of cell viability and metabolic activity. The menisci preserved in 1% and 5% formaldehyde solution showed a decreased radioactive uptake as well as LDH activity.