Michiro Yamamoto

Importance of distal radioulnar joint arthroscopy for evaluating the triangular fibrocartilage complex

BackgroundThe present study evaluated the importance of visualizing both sides of the triangular fibrocartilage complex (TFCC) when diagnosing ulnar wrist pain.MethodsA total of 20 patients with ulnar wrist pain who underwent both radiocarpal joint (RCJ) and distal radioulnar joint (DRUJ) arthroscopy were studied retrospectively. TFCC was graded as normal or as having wear or tear. The definitive diagnosis was made by evaluating the TFCC from both joints. The medical records were reviewed to document the preoperative diagnosis, arthroscopic findings, postoperative diagnosis, and operative procedure(s) performed after the arthroscopic examinations. The patients’ status at final follow-up was evaluated using the modified Green and O’Brien wrist scoring system. The TFCC grading on RCJ and DRUJ arthroscopies was compared.ResultsThe final diagnosis was modified after arthroscopic examination in three cases (15%). In six patients (30%), DRUJ arthroscopy revealed pathological TFCC findings that could not be detected on RCJ arthroscopy. The DRUJ arthroscopy detected wear or degenerative changes seen only on the proximal aspect of the TFCC in four patients and tear in two patients. On the other hand, in only one patient (5%) were there no pathological findings observed from the DRUJ portal, although RCJ arthroscopy found wear. In eight patients (45%), the arthroscopic grading of TFCC was the same on RCJ and DRUJ arthroscopy; of these, the TFCC was graded as normal in one patient, showing wear in three patients, and with a tear in five patients. For diagnosing TFCC pathology, RCJ arthroscopy had a sensitivity of 68% and a negative predictive value (NPV) of 14%, whereas the sensitivity was 95% and the NPV was 50% for DRUJ.ConclusionsAdding DRUJ arthroscopy to RCJ arthroscopy enables more accurate diagnosis of TFCC pathology because the proximal aspect of the articular disk and the foveal insertion of the distal radioulnar ligament can be visualized.

Targeting Anti-Inflammatory Treatment Can Ameliorate Injury-Induced Neuropathic Pain

Tumor necrosis factor-α plays important roles in immune system development, immune response regulation, and T-cell-mediated tissue injury. The present study assessed the net value of anti-tumor necrosis factor-α treatment in terms of functional recovery and inhibition of hypersensitivity after peripheral nerve crush injury. We created a right sciatic nerve crush injury model using a Sugita aneurysm clip. Animals were separated into 3 groups: the first group received only a skin incision; the second group received nerve crush injury and intraperitoneal vehicle injection; and the third group received nerve crush injury and intraperitoneal etanercept (6 mg/kg). Etanercept treatment improved recovery of motor nerve conduction velocity, muscle weight loss, and sciatic functional index. Plantar thermal and von Frey mechanical withdrawal thresholds recovered faster in the etanercept group than in the control group. On day 7 after crush injury, the numbers of ED-1-positive cells in crushed nerves of the control and etanercept groups were increased compared to that in the sham-treated group. After 21 days, ED-1-positive cells had nearly disappeared from the etanercept group. Etanercept reduced expression of interleukin-6 and monocyte chemotactic and activating factor-1 at the crushed sciatic nerve. These findings demonstrate the utility of etanercept, in terms of both enhancing functional recovery and suppressing hypersensitivity after nerve crush. Etanercept does not impede the onset or progression of Wallerian degeneration, but optimizes the involvement of macrophages and the secretion of inflammatory mediators.

Administration of umbilical cord blood cells transiently decreased hypoxic-ischemic brain injury in neonatal rats.

This study aimed to investigate whether the administration of mononuclear cells derived from human umbilical cord blood cells (UCBCs) could ameliorate hypoxic-ischemic brain injury in a neonatal rat model. The left carotid arteries of 7-day-old rats were ligated, and the rats were then exposed to 8% oxygen for 60 min. Mononuclear cells derived from UCBCs using the Ficoll-Hypaque technique were injected intraperitoneally 6 h after the insult (1.0 × 107 cells). Twenty-four hours after the insult, the number of cells positive for the oxidative stress markers 4-hydroxy-2-nonenal and nitrotyrosine, in the dentate gyrus of the hippocampus in the UCBC-treated group, decreased by 36 and 42%, respectively, compared with those in the control group. In addition, the number of cells positive for the apoptosis markers active caspase-3 and apoptosis-inducing factor decreased by 53 and 58%, respectively. The number of activated microglia (ED1-positive cells) was 51% lower in the UCBC group compared with the control group. In a gait analysis performed 2 weeks after the insult, there were no significant differences among the sham-operated, control and UCBC groups. An active avoidance test using a shuttle box the following week also revealed no significant differences among the groups. Neither the volumes of the hippocampi, corpus callosum and cortices nor the numbers of neurons in the hippocampus were different between the UCBC and control groups. In summary, a single intraperitoneal injection of UCBC-derived mononuclear cells 6 h after an ischemic insult was associated with a transient reduction in numbers of apoptosis and oxidative stress marker-positive cells, but it did not induce long-term morphological or functional protection. Repeated administration or a combination treatment may be required to achieve sustained protection.

Clinical, Radiographic, and Arthroscopic Outcomes After Ulnar Shortening Osteotomy: A Long-Term Follow-Up Study

PURPOSE Previous studies have investigated the long-term outcomes of ulnar shortening osteotomy (USO) in the treatment of ulnocarpal abutment syndrome (UCA), but none have used arthroscopic assessments. The purpose of this study was to investigate the long-term clinical outcomes of USO with patient-based, arthroscopic, and radiographic assessments. METHODS We retrospectively reviewed 30 patients with UCA after a minimum follow-up of 5 years, with arthroscopic evaluations at the time of both USO and plate removal. We confirmed the initial diagnosis of UCA by radiography and arthroscopy. Mean age at the time of index surgery was 37 years. Mean duration of follow-up was 11 years (range, 5-19 y). We obtained Disabilities of the Arm, Shoulder, and Hand and Hand20 self-assessments postoperatively for all patients. Bony spur formation was evaluated postoperatively from plain radiographs. RESULTS We detected triangular fibrocartilage complex (TFCC) disc tear in 13 wrists arthroscopically at the time of USO. Of these, 10 showed no evidence of TFCC disc tear at second-look arthroscopy. The remaining 17 cases showed no TFCC disc tear at either first- or second-look arthroscopy. Follow-up radiography revealed that bony spurs at the distal radioulnar joint had progressed in 13 wrists. Disabilities of the Shoulder, Arm, and Hand and Hand20 scores did not significantly correlate with the presence of bony spurs or TFCC disc tears. Range of motion decreased significantly with age only. Lower grip strength correlated with bony spur and lower radial inclination. Triangular fibrocartilage complex tear, male sex, and advanced age were associated with lower Disabilities of the Shoulder, Arm, and Hand and Hand20 scores. CONCLUSIONS Ulnar shortening osteotomy achieved excellent long-term results in most cases. Most TFCC disc tears identified at the initial surgery had healed by long-term arthroscopic follow-up. We suggest that UCA with a TFCC disc tear is a good indication for USO.

Sonography-guided Arthroscopy for Wrist Ganglion

PURPOSE To describe how to combine the complementary features of sonography and arthroscopy to make the arthroscopic resection of wrist ganglions a safer and more reliable surgery. METHODS A total of 22 patients with wrist ganglions had sonography-assisted arthroscopic resection. Sonographic visualization of ganglions, adjacent structures (ie, vessels, nerves, and tendons), and the cycling tip of the arthroscopic shaver was assessed. Arthroscopic visualization of the ganglions or ganglion stalk was also assessed. Clinical outcome measures included wrist range of motion, grip strength, and our patient-rated Hand 20 questionnaire. RESULTS Sonographic visualization of the ganglion stalk, adjacent structures, and the cycling tip of the arthroscopic shaver was possible in all 22 cases. However, ganglion stalks were visualized by arthroscopy in only 4 cases. The mean range of motion and grip strength were not significantly changed following surgery. However, the mean Hand 20 score was significantly improved from 17 to 6 at final follow-up. Ganglion recurrence was seen in 2 cases at 6 and 8 months after surgery. CONCLUSIONS Sonography-guided wrist arthroscopy provides several advantages for surgeons, including visualization of the ganglions and ganglion stalk, as well as of the arthroscopic shaver and adjacent structures such as nerves, vessels, and tendons to perform surgery safely.

Novel polysaccharide-derived hydrogel prevents perineural adhesions in a rat model of sciatic nerve adhesion.

We investigated the effects of a novel carboxymethylcellulose (CMC)‐derived hydrogel, in which phosphatidylethanolamine (PE) was introduced into the carboxyl groups of CMC, for preventing perineural adhesion after extensive internal neurolysis of rat sciatic nerve. Sciatic nerves were randomly assigned to one of the following groups: the Control group, operated but no treatment; the HA group, operated and treated with 1% hyaluronan; the CMC–PE(L) group, operated and treated with low‐viscosity CMC–PE hydrogel; and the CMC–PE(H) group, operated and treated with high‐viscosity CMC–PE hydrogel. Perineural adhesions were evaluated at 6 weeks. Nerves were also subjected to biomechanical testing to assess ultimate breaking strength. Electrophysiological and wet muscle weight measurements were performed. Breaking strengths were significantly lower for the CMC–PE(L) group than for the Control and HA groups. Latency was significantly longer for the Control group than for the CMC–PE(L) group at 20 days. The mean percentage of wet muscle weight to body weight was significantly lower for the Control group than for the CMC–PE(L) group at 6 weeks. Low‐viscosity CMC–PE hydrogel appears to prevent perineural adhesions and allow early restoration of nerve function.

Simple debridement has little useful value on the clinical course of recalcitrant ulnar wrist pain

The purpose of this study was to evaluate treatment results following arthroscopic triangular fibrocartilage complex (TFCC) debridement for recalcitrant ulnar wrist pain. According to the treatment algorithm, 66 patients (36 men and 30 women with a mean age of 38.1 years (15 to 67)) with recalcitrant ulnar wrist pain were allocated to undergo ulnar shortening osteotomy (USO; n = 24), arthroscopic TFCC repair (n = 15), arthroscopic TFCC debridement (n = 14) or prolonged conservative treatment (n = 13). The mean follow-up was 36.0 months (15 to 54). Significant differences in Hand20 score at 18 months were evident between the USO group and TFCC debridement group (p = 0.003), and between the TFCC repair group and TFCC debridement group (p = 0.029). Within-group comparisons showed that Hand20 score at five months or later and pain score at two months or later were significantly decreased in the USO/TFCC repair groups. In contrast, scores in the TFCC debridement/conservative groups did not decrease significantly. Grip strength at 18 months was significantly improved in the USO/TFCC repair groups, but not in the TFCC debridement/conservative groups. TFCC debridement shows little benefit on the clinical course of recalcitrant ulnar wrist pain even after excluding patients with ulnocarpal abutment or TFCC detachment from the fovea from the indications for arthroscopic TFCC debridement.

Regeneration of the perineurium after microsurgical resection examined with immunolabeling for tenascin-C and alpha smooth muscle actin

The regenerative process of the perineurium and nerve function were examined using an in vivo model of perineurium resection in the rat sciatic nerve. Our hypothesis is that the regenerative process of the perineurium can be demonstrated by immunolabeling for tenascin‐C and alpha smooth muscle actin after microsurgical resection of the perineurium in vivo. A total of 38 Lewis rats were used. Eight‐week‐old animals were assigned to one of two groups: the epi‐perineurium removal group or the sham group. Under operative microscopy, the sciatic nerve was dissected from surrounding tissues at the thigh level from the ischial tuberosity to the fossa poplitea. The epi‐perineurium was carefully removed by cutting circumferentially and stripping distally for 15 mm. For CatWalk® dynamic gait analysis, only right sciatic nerves underwent surgery; the left sciatic nerves were left intact. For pathological and electrophysiological tests, both the right and left sciatic nerves underwent surgery. Analysis of data was performed at each time interval with a two‐group t‐test. P < 0.05 was considered statistically significant. After resection of a 15‐mm section of the epi‐perineurium, immediate endoneurial swelling occurred in the outer portion and spread into the central portion. Although demyelination and axonal degeneration were found in the swollen area, remyelination and recovery of electrophysiological function were seen after regeneration of the perineurium. An immunohistological and electron microscopic study revealed that the perineurium regenerated via fusion of the residual interfascicular perineurium and endoneurial fibroblast‐like cells of mesenchymal origin. CatWalk gait analysis showed not only motor paresis but also neuropathic pain during the early phases of this model.

Development and validation of a ten-item questionnaire with explanatory illustrations to assess upper extremity disorders: favorable effect of illustrations in the item reduction process

BackgroundThe purpose of this study is to develop a short and valid measure for upper extremity disorders and to assess the effect of attached illustrations in item reduction of a self-administered disability questionnaire while retaining psychometric properties.MethodsA validated questionnaire used to assess upper extremity disorders, the Hand20, was reduced to ten items using two item-reduction techniques. The psychometric properties of the abbreviated form, the Hand10, were evaluated on an independent sample that was used for the shortening process.ResultsValidity, reliability, and responsiveness of the Hand10 were retained in the item reduction process. It was possible that the use of explanatory illustrations attached to the Hand10 helped with its reproducibility. The illustrations for the Hand10 promoted text comprehension and motivation to answer the items. These changes resulted in high acceptability; more than 99.3% of patients, including 98.5% of elderly patients, could complete the Hand10 properly.ConclusionThe illustrations had favorable effects on the item reduction process and made it possible to retain precision of the instrument. The Hand10 is a reliable and valid instrument for individual-level applications with the advantage of being compact and broadly applicable, even in elderly individuals.

A new nerve coaptation technique using a biodegradable honeycomb‐patterned film

We developed a biodegradable poly‐lactide (PLA) film with a honeycomb‐patterned porous structure (honeycomb film). This study investigated the use of this film in neurorrhaphy. Three types of PLA film were tested following bilateral sciatic nerve transection and neurorrhaphy in 35 rats: 7‐ and 10‐μm thick honeycomb films, and cast film with no porous structures. Initially, following two‐stitch neurorrhaphy, 40 limbs (20 rats) underwent wrapping in 7‐ or 10‐μm honeycomb film, cast film, no wrapping, or extra two‐stitch neurorrhaphy (8 limbs each). Breaking strength was tested 2 days postoperatively. Another 30 limbs (15 rats) then underwent wrapping in 7‐ or 10‐μm honeycomb film, cast film, no wrapping, or sham operation (six limbs each). Histological and functional analyses were performed 6 weeks postoperatively. Breaking strength was significantly higher for the 10‐μm honeycomb film than for no wrapping (P = 0.013), although no significant difference was observed between the 7‐μm honeycomb and no wrapping (P = 0.085). Breaking strength for the cast film was almost equal to that for no wrapping (P = 0.994). Extra two‐stitch (four‐stitch) neurorrhaphy was significantly stronger than all groups, except the 10‐μm honeycomb group. No significant difference was observed between the 10‐μm honeycomb and the four‐stitch (P = 0.497). No negative effects on functional recovery were identified. No adhesions or inflammation were observed between the film and surrounding tissues in the honeycomb groups. Honeycomb film may offer a suitable reinforcing material for adhesion‐free neurorrhaphy.