Koji Ryoke

Mechanoreceptors in the anterior cruciate ligament contribute to the joint position sense.

We have investigated the correlation between the number of mechanoreceptors in anterior cruciate ligament (ACL) remnants and the joint position sense just before an ACL reconstruction in 29 patients. The number of mechanoreceptors was evaluated histologically, using the Gairns gold chloride method. Mechanoreceptors were also found in patients who had a long interval between injury and the operation. A joint position sense test was done within 3 days before surgery. We found a positive correlation between the number of mechanoreceptors and accuracy of the joint position sense, suggesting that proprioceptive function of the ACL is related to the number of mechanoreceptors. Therefore, we should consider preserving ACL remnants during ACL reconstruction.

Tension band fixation for treatment of patellar fracture: Novel technique using a braided polyblend sutures and ring pins

AIM To evaluate a new tension band fixation technique for patellar fracture using braided polyblend sutures (PBSs) and ring pins (RPs). METHODS A total of 13 patients (average: 58.2 years) with transverse or comminuted patellar fractures were treated by this technique. From the 4th week after the surgery, normal activities of daily living were permissible. RESULTS Bone union was achieved at a mean 3 months from surgery, without any cases of failure, redislocation or postoperative complication. At 12 months after surgery, mean Lysholm score was 93.6, knee motion was extension 0.8 degrees to flexion of 134.6 degrees and visual analogue pain score was 0.5. CONCLUSION The new tension band fixation technique using braided polyblend sutures resulted in good outcomes and is considered clinically effective for patellar fracture reduction.

Unilateral sciatic nerve injury stimulates contralateral nerve regeneration.

Axonal outgrowth in tissue cultures was measured to determine whether unilateral peripheral nerve injuries affect contralateral nerve regeneration. The right sciatic nerves of young male Wistar rats were cut at mid-thigh level. Sham operation as a control was limited to the exposure of the nerve without cutting. At day 6 post-surgery, bilateral L5 dorsal root ganglia (DRG) with attached nerve stumps were resected and cultured. Axonal outgrowth from the nerve stump was measured in situ. The contralateral preparations showed longer outgrowths than controls. Therefore the conditioning effect was not merely restricted to the ipsilateral neurons but also affected undamaged sensory neurons of the contralaretal DRG.

ATYPICAL COMPRESSION OF THE DEEP BRANCH OF THE ULNAR NERVE IN GUYON'S CANAL BY A GANGLION: Case report

A 61-year-old woman with an ulnar claw-finger deformity but no sensory loss had a cystic lesion excised from Guyons canal. The ganglion was in zone 1 of the canal, which is associated with both motor and sensory deficit, but on this occasion it caused motor dysfunction alone.A 61-year-old woman with an ulnar claw-finger deformity but no sensory loss had a cystic lesion excised from Guyons canal. The ganglion was in zone 1 of the canal, which is associated with both motor and sensory deficit, but on this occasion it caused motor dysfunction alone.

Comparison of elastic versus rigid suture material for peripheral sutures in tendon repair

BACKGROUND For secure tendon repair, while core suture materials have been previously investigated, the optimum material for peripheral sutures remains unclear. METHODS Transected bovine gastrocnemius tendons were repaired by 2-strand side-locking loop technique using no.2 braided polyblend polyethylene thread for the core suture. Then, 8-strand peripheral cross-stitches were added using either 2-0 rigid sutures (braided polyblend polyethylene) or USP 2-0-sized elastic sutures (nylon). The holding area of each peripheral suture was set at either 3 × 1 mm (shallow holding) or 6 × 2 mm (deep holding). Therefore, 4 groups were compared (the shallow-rigid, deep-rigid, shallow-elastic, and deep-elastic groups). The gap formation, ultimate tensile strength, and suture migration state were measured after 500 cyclic loadings (from 10 to 200 N). METHODS The shallow-rigid group had inferior outcomes compared to the other groups. Although the deep-rigid group had the smallest gap and highest ultimate strength, all peripheral sutures had failure prior to core suture rupture. The two elastic groups showed no significant differences, irrespective of the size of the holding area. Suture migration did not occur in the two elastic groups until the ultimate strength was reached and the core suture ruptured. INTERPRETATION Depending on the suturing method, rigid suture material may not be appropriate for peripheral sutures, when accompanying rigid core suture material. If peripheral sutures can be made with accurate deep holding, rigid suture material will provide favorable outcome. However, in other cases, elastic suture material is considered best for supporting a rigid core suture, as elasticity is another important factor for peripheral sutures.

EXPRESSION OF CYTOKINES IN THE DORSAL ROOT GANGLION CELL BODY IN AN EXPERIMENTAL MODEL OF ENTRAPMENT NEUROPATHY

An experimental entrapment neuropathy model was produced by wrapping the sciatic nerve with a silicone tube using 54 adult male Wistar rats. We observed the changes in expression of IL-1 and TGF-β1 in the dorsal root ganglion during the formation as well as recovery process after removal of the tube, together with electrophysiological changes. Expression of IL-1 reached its peak 2 months after tubing, while expression of TGF-β1 peaked at 6 months and thereafter slowly decreased. Motor nerve conduction velocity (MNCV) significantly decreased 8 months after tubing. Removal of the silicone tube at 8 months after tubing, induced a significant increase in the level of IL-1 expression at 1 month after the removal, and that in the level of TGF-β1 expression at 2 months after the removal, at which time MNCV began to show a significant recovery. We have concluded from these results that IL-1 and TGF-β1 are deeply involved in the formation as well as the recovery process of entrapment neuropathy.

High contrast between lumbar nerve roots and surrounding structures using dual echo 3D turbo spin echo additional fusion images

PurposeWe performed lumbar spinal magnetic resonance imaging of three-dimensional (3D) dual echo volumetric isotropic turbo spin echo acquisition (DE-VISTA) and constructed DE-VISTA additional fusion images (DE-VISTA-AFI), which is the addition of DE-VISTA proton density-weighted images (DE-VISTA-PDWI) to DE-VISTA T2-weighted images (DE-VISTA-T2WI). The aim of this study was to clarify whether DE-VISTA-AFI was able to clearly delineate spinal nerve roots.MethodsA total of 677 patients underwent lumbar MR imaging, and the signal ratio (SR) between cerebrospinal fluid and nerve roots inside the dural sac and the SR between fat and nerve roots outside the dural sac were estimated using DE-VISTA-AFI, DE-VISTA-PDWI, DE-VISTA-T2WI, and 2D-T2WI.ResultsThe SR between cerebrospinal fluid and nerve roots inside the dural sac on DE-VISTA-AFI was higher than that on DE-VISTA-PDWI (p < 0.0001) and on 2D T2WI (p < 0.0001). The SR between the fat tissue and nerve roots outside the dural sac on DE-VISTA-AFI was higher than that on DE-VISTA-PDWI (p < 0.0001) and 2D T2WI (p < 0.0001).ConclusionDE-VISTA-AFI could clearly delineate the entire length of the lumbar nerve roots that run from the cauda equina in the spinal fluid through to the fat in the lateral recess, intervertebral foramen, and outside the intervertebral foramen.

Usefulness of braided polyblend polyethylene suture material for flexor tendon repair in zone II by the side-locking loop technique.

Flexor tendon injuries in zone II were treated in 14 fingers of 13 patients with our method. Firstly, a 2-strand core suture was made by the side-locking loop technique using a USP 2-0-sized braided polyblend polyethylene suture, then 7-strand peripheral cross-stitches were added using a USP 5-0-sized monofilament nylon suture. Post-operative exercises included passive flexion and extension without external fixation on the next day of surgery. Average follow-up observation period was 18 months. As results, the Strickland method of assessment for surgical outcome showed excellent in eight digits and good in five digits, though there was a poor outcome in one digit. Our suture method enabled early post-operative mobilisation exercise without using a splint, while preventing adhesion between the repaired tendon and peripheral tissues, which is considered to provide far greater ultimate tensile strength and a smaller gap at the sutured site than by the conventional method.