One of the important tasks during obstetric brachial plexus palsy (OBPP) reconstruction is determining the extent of proximal and distal nerve stump shortening required to obtain unscarred nerve material. Evaluation of nerve stumps under loupe magnification has been used in some centres as the sole means of determining stump quality. Frozen section histology is used by others to assess the internal architecture of the nerve stumps, but is time consuming and labor intensive. We have designed a study to evaluate the ability of frozen section histology to demonstrate an improvement in internal architecture on re-cuts of damaged nerve stumps.

Our method for OBPP reconstruction involves excising the proximal and distal nerve stumps under loupe magnification until a normal fascicular pattern is observed. Biopsies of all proximal and distal stumps are sent for frozen section analysis using toluidine blue staining. If the internal nerve architecture is not acceptable, the nerve stumps are re-cut until frozen section histology reveals acceptable nerve or until further re-cuts are not possible anatomically.

All 233 children undergoing primary reconstruction in our centre for OBPP from 1988 – 2003 had intraoperative frozen section analysis of the proximal and distal nerve stumps. The patients who required re-excision of a nerve stump due to unacceptable histology on frozen section analysis form the study population. Their pre and post re-excision histology are being reviewed retrospectively in a blinded fashion by a single neuropathologist. The specimens are scored using a new 11-point scale, which assesses the condition of the endoneurium, perineurium and epineurium. The score and features of the initial biopsy will be compared to those of the re-cut for the same nerve stump using multiple analysis of variance.

59 of 233 patients (25%) undergoing OBPP reconstruction that appeared to have a normal fascicular pattern using loupe magnification required re-excision of at least one nerve stump because of poor nerve architecture as demonstrated by frozen section histology. Of a total of 1325 nerve stumps evaluated in these 233 patients, 79 stumps (6%) required re-excision to obtain acceptable nerve prior to proceeding with grafting. Data to determine the ability of frozen section histology to demonstrate an improvement in internal architecture on re-cuts of damaged nerve stumps will be presented. A new grading scale used to assess peripheral nerve histology following trauma will be described.