The Study Of High-resolution Ultrasonography In The Diagnosis For Common Peroneal Nerve

ObjectiveTo study the ultrasonographic appearance of normal common peroneal nerves and common peroneal nerve lesions,including neurotmesis,nerve compression and nerve tumor.To diagnose the regeneration of sutured common peripheral nerves by high-resolution ultrasonography.To evaluate the diagnostic value of high-resolution ultrasonography by comparing with findings in operation and electromyography.Materials and MethodsThe common peroneal nerves of 20 healthy adults were examined by high-resolution ultrasonography to study the course,modality and ultrasonographic features of normal common peroneal nerves.The level of fibular neck and popliteal fossa were chosen as two measurement points,the diameters and cross-sectional areas of the nerves were measured on both sides.The results of quantitative analysis in corresponding groups were compared with a t-test.A two-side P value of less than 0.05 was considered statistically.The overall means of normal common peroneal nerve were estimated.Ultrasonographic examinations were performed in 29 patients with clinical common peroneal nerve lesions,who were then operated in Department of Hand Surgery in our hospital from March 2006 to June 2008.The continuity,modality, ultrasonographic features and the relationship with the surrounding tissue of common peroneal nerves were observed.Ultrasonographic findings were compared with results of surgeries.The features of each type of common peroneal nerve lesion were summarized and the ultrasonographic accuracy was calculated comparing with intraoperative findings that were regarded as gold standard.Ultrasonographic examinations were performed in 12 patients who received poor recovery after common peroneal nerve suture and were performed second operation in Department of Hand Surgery in our hospital from Aug 2006 to April 2008.The continuity,the size and the internal structure of the anastomotic stomas were observed. The regeneration of sutured common peripheral nerves was diagnosed by the characteristic images.The ultrasonographic results were compared with intraoperative findings and the ultrasonographic accuracy was calculated comparing with intraoperative electromyography that was regarded as gold standard.ResultsThe ultrasonographic appearance of normal common peroneal nerve:fascicular structure when scanned in a longitudinal plane and honeycomb structure when scanned in a transverse plane.Real-time dynamic scanning shows that common peroneal nerve is derived from sciatic nerve.It lies between biceps femoris and semitendinosus,seminal colliculus,on the lateral side of tibial nerve.It descends obliquely along the medial side of the tendon of biceps femoris to the lateral side of popliteal fossa.It winds around fibular neck,and divides beneath peroneus longus into the superficial peroneal nerve and deep peroneal nerve.Statistical analysis of measurement differences between bilateral common peroneal nerves shows no statistical significance.At the level of fibular neck,cross-sectional area of common peroneal nerve is 0.140±0.042cm~2 and the diameter is 0.312±0.067cm.At the level of popliteal fossa,cross-sectional area of common peroneal nerve is 0.115±0.034cm~2 and the diameter is 0.245±0.050cm.Common peroneal nerve lesions were classified into 3 types:neurotmesis,nerve compression and nerve tumor.Ultrasonographic manifestation of each type appeared as follows.Complete neurotmesis:the continuity of hypoechoic nerve tracts and hyperechoic epineurium was interrupted.Neuroma could form at the broken end of the peroneal nerve.Incomplete neurotmesis:the continuity of some nerve tracts was interrupted,while continuity of other nerve tracts was maintained.Tendinous compression:sectional narrow was seen,while both the proximal and the distal end or the proximal section of common peroneal nerve was thicken and hypoechoic. Compression by adherent scar:common peroneal nerve was stuck tightly by hypoechoic scar or enwrapped in surrounding scar,while both the proximal and the distal end or the proximal section of common peroneal nerve was thicken and hypoechoic.Traumatic neuroma:a hypoechoic enlargement at the broken end or sutured site of the nerve.Schwannoma or neurofibroma appeared as a well-defined hypoechoic mass in continuity with the proximal and distal nerve tracts.Intraneural ganglion:a spindle-shaped intumesence with some secion of the nerve appeared as multi-loculus anechoic structure.35 common peroneal nerve lesions were examined by high-resolution ultrasonography in 29 patients.1 tendinous compression was misdiagnosed.1 tendinous compression and 1 nerve compression by adherent scar were missed.The ultrasonographic accuracy was 91.4%(32/35).The ultrasonographic images of anastomotic stomas in sutured common peroneal nerves were classified into 4 types.Ultrasonographic manifestation of each type appeared as follows.Type-Ⅰ-stoma:the nerve tracts passing the stoma were well jointed.The regeneration of the nerve was diagnosed as fine.Type-Ⅱ-stoma: continuous nerve tracts were seen passing the stoma with adherent hypoechoic scar. The regeneration of the nerve was diagnosed as fine.Type-Ⅲ-stoma:an enormous neuroma surrounded by much hypoechoic scar.The nerve tracts in the stoma were poorly jointed while many hyperechoic short sticks could be seen on the epineurium or perineurium.The regeneration of the nerve was diagnosed as poor or possibly fine. Type-Ⅳ-stoma:the hypoechoic cords passing the stoma were thin and homogeneous. Stegnosis of the nerve could be formed by compression from the peripheral scar.The regeneration of the nerve was diagnosed as poor or possibly fine.17 anastomotic stomas in sutured common peroneal nerves of 12 patients were examined by high-resolution ultrasonograpgy.The regeneration of 2 type-Ⅲ-stoma and 1 type-Ⅳ-stoma whose SEP were negative were misdiagnosed as fine.The ultrasonographic accuracy was 82.4%(14/17).ConclusionsHigh-resolution ultrasonography can display the modality and course of a normal common peroneal nerve.The ultrasonographic appearance of normal common peroneal nerve:fascicular structure when scanned in a longitudinal plane and honeycomb structure when scanned in a transverse plane.At the level of fibular neck and popliteal fossa,differences of the diameters and cross-sectional areas between bilateral common peroneal nerves show no statistical significance.High-resolution ultrasonography can display the morphologic changes such as neurotmesis,nerve compression and nerve tumor.It can locate the lesions,suggest the extent of surgery,and improve the opportunity of surgery.Ultrasonography can diagnose the regeneration of sutured common peripheral nerves earlier than electromyography,and point out some reasons that result in poor recovery,providing effective help to clinician in choosing second operation.Scar is the main reason that interferes in the diagnosis of the regeneration of sutured common peripheral nerves.