Kenichi Tazaki

Fascicular constrictions in patients with spontaneous palsy of the anterior interosseous nerve and the posterior interosseous nerve.

Abstract There is no definition for fascicular constrictions of the spontaneous anterior interosseous nerve palsy (sAINP) and spontaneous posterior interosseous nerve palsy (sPINP). One surgeon has evaluated his findings in our 32 patients of sAINP/sPINP using either photographs or video tapes and proposed a definition. All patients had interfascicular neurolysis, and 87 case reports of “fascicular constriction” were also evaluated. Fascicular constriction was defined as every instance of thinning in the fascicle regardless to its extent. Thinning as a result of extrinsic compression was excluded. The fascicular constrictions were divided into four types: recessed, recessed-bulging, rotation, and rotation-bulging constriction. Two independent surgeons went through our findings to verify their repeatability. The relation between the fascicular constrictions and age at the onset of palsy was evaluated using Students t test. We found 54 fascicular constrictions, with many variations. However, they could all be categorised by our method. The repeatability among the independent authors was 96%. The age at the onset of palsy was significantly younger in rotation-bulging than in rotation constriction (p = 0.0003). Our definition of describing fascicular constrictions was accurate, and should help to provide consensus in describing these palsies.

Tendon Entrapment in Distal Radius Fractures

We retrospectively defined the rate and clinical features of tendon entrapment in 693 consecutive patients with 701 distal radius fractures treated in a single hospital. Eight extensor tendons and one flexor tendon were entrapped. All fractures with extensor tendon entrapment were palmarly displaced (Smith type) or epiphyseal. Flexor tendon entrapment was seen in dorsally angulated (Colles type) epiphyseal fracture. The rate of tendon entrapment in acute distal radius fractures was 1.3%. Extensor tendon entrapment in palmarly displaced fractures is more common.

Surgical treatment of spontaneous anterior interosseous nerve palsy: A comparison between minimal incision surgery and wide incision surgery

Abstract Recent reports have suggested that fascicular constriction located proximal to the elbow may be the primary aetiology of spontaneous anterior interosseous nerve palsy (sAINP), and recommended interfascicular neurolysis ranging from the proximal forearm to distal upper arm (wide incision surgery: WIS) for its treatment. On the basis of these reports, it was hypothesised that, if the aetiology of sAINP was fascicular constriction, neurolysis limited proximal to the elbow (minimal incision surgery: MIS) should have similar results to those of WIS. Twenty-five surgically treated sAINP cases were retrospectively evaluated. The mean age of onset was 42.8 years, the mean preoperative period was 5.3 months, and mean follow-up period after operation was 31 months. Eleven patients underwent MIS, while 14 underwent WIS according to the patients intention (intention-to-treat). Twenty-one patients had fascicular constriction, and no entrapment neuropathy was seen in this series. At the latest follow-up, 82% of the patients had British Medical Research Council grade of ≥4 in flexor-pollicis-longus, while 80% had grade of ≥4 in flexor-digitorum-profundus-of-the-index-finger. There were no significant differences between the results of either group. These result suggested that the aetiology of sAINP may not be external compression, but fascicular constriction, and MIS may be its favourable surgical treatment.

Extensor tendon entrapment in volarly displaced distal radial fracture

A 37 year-old right hand dominant man fell down a staircase and injured his left wrist. When he attended our hospital the day after the injury, his wrist was grossly swollen and deformed. Although he complained of pain when the digits were fully flexed, he could still actively extend and flex his thumb and fingers. Radiographs showed a volarly displaced distal radial fracture associated with dorsal dislocation of the ulnar head. Because the fracture was dislocated and had a gap between the fragments, MRI was carried out in order to assess soft tissue interposition at the fracture site. Axial MRI indicated that the EPL, EIP, EDCs and EDM tendons had passed between the radius and the ulna onto their volar aspect (Fig 1). After failed closed reduction under general anaesthesia, the dorsal aspect of the wrist was explored. The proximal stump of the radius was found extruding through the extensor retinaculum with no tendons on the dorsal aspect: the extensor tendons had passed through the disrupted forearm interosseous membrane onto the volar aspect of the radius proximal stump. Application of traction and extension force to the wrist, as for closed reduction of a Smith’s fracture, exacerbated the trapping and damage to the tendons. After the tendons had been relocated, the distal radial fracture was reduced easily and internally fixed with a buttress plate through a volar approach. The triangular fibro-cartilage complex was then reattached to the fovea of the ulna. On review, 2 years after the operation, the patient had obtained satisfactory wrist function without pain and full range of digital motion. He returned to his original job as an electrician. Entrapment of extensor tendons in association with Smith’s fracture has been reported (El-Kazzi and Schuind, 2005; Itoh et al., 1987). In previous reports, tendon entrapment has been suspected because of failure of closed reduction, loss of active extension in digits, positive tenodesis effect and/or residual dorsal wrist pain. If there are few symptoms, it is very difficult to diagnose the tendon entrapment pre-operatively. The case presented here is unusual in that MRI was used primarily because of the severe displacement of the fracture, although there was no restriction of active motion of the digits. We presume that the patient could move the digits because the fracture was displaced and the tendons were loosely interposed, not crushed, at the fracture site. We believe MRI is effective in identifying interposition of the extensor tendons pre-operatively. As it costs more than a simple X-ray, MRI being approximately 22,000 yen (approx. £100, 150h) and a plain X-ray 2500 yen (approx. £11, 17h), we suggest MRI only be used when there is a gap between the radial shaft and the displaced volar fragment. When an MRI cannot be obtained, the dorsal aspect of the wrist should be explored to check for tendon entrapment.

Slow progression predicts poor prognoses in patients with spontaneous posterior interosseous nerve palsy

Abstract There are still no factors that predict the prognoses of patients with spontaneous posterior interosseous nerve palsies who are in an early phase of the illness. This paper reviewed 39 patients with this type of palsy. Seventeen patients who requested surgery for possible earlier recovery underwent interfascicular neurolysis because no signs of recovery were seen more than 3 months after onset. A Medical Research Council muscle power grade over 4 at their final visit was considered a good result, while a power less than grade 4 was considered a poor result. The clinical outcomes were significantly worse for the patients who had palsies with slow progressions (for more than 1 month) compared with those who had palsies with rapid progressions (completed within 1 month), regardless of their treatment. No significant difference was seen between the prognoses of patients with complete and incomplete palsies. We, therefore, recommend that interfascicular neurolysis is performed together with tendon transfer as the primary surgical procedures for patients with palsies with slow progression.

A CASE REPORT OF A GIANT FOREARM LIPOMA CAUSING ANTERIOR INTEROSSEOUS NERVE PALSY AFTER FRACTURE OF THE DISTAL RADIUS

To the best of our knowledge, there are no previous reports on anterior interosseous nerve palsy (AINP) caused by a soft tissue tumor after fracture of the distal radius. We treated a case of giant forearm lipoma that caused AINP one day after internal fixation of a distal radius fracture.