Minoru Doita

Glenohumeral arthrodesis for malignant tumor of the shoulder girdle

BACKGROUND Arthrodesis of the shoulder joint using a free vascularized fibular graft has been performed as a reconstruction method after resection of bone sarcoma in the shoulder girdle. Postoperative fractures occasionally occur as a complication of arthrodesis of the shoulder joint using single-bone fusion (the conventional method). We hypothesized that the clinical results of shoulder arthrodesis using a double-barrel vascularized fibula graft for the malignant tumor of the shoulder girdle would achieve superior results compared with the conventional single-bone fusion method. METHODS The clinical results of 5 patients with a malignant bone and soft tissue tumor of the shoulder girdle were retrospectively reviewed. The factors evaluated were surgical margins, reconstruction procedures, postoperative complications, local recurrences, metastasis in lymph nodes or lung, or both, survival, and functional results assessed by the Musculoskeletal Tumor Society (MSTS) score. After surgical resection, arthrodesis of the shoulder joint was performed using a free vascularized fibula graft as a reconstructive procedure for the bone defect. Arthrodesis was by single-bone fusion in 3 of 5 patients, and a double-barrel vascularized fibula graft (dual-bone fusion) was used in 2 patients. RESULTS The average MSTS scores were 58.3% in the group with single-bone fusion and 85.0% in the group with dual-bone fusion. CONCLUSION The use of a double-barrel vascularized fibular graft may be useful in the reconstruction of large bone defects after wide excision of malignant tumors of the proximal humerus, with the advantage of avoiding postoperative fractures in shoulder arthrodesis.

Comparison of the Sliding and Femoral Head Rotation among Three Different Femoral Head Fixation Devices for Trochanteric Fractures

Background Recently, various femoral head fixation devices (HFDs) for trochanteric fractures have become available. However, there are some cases in which femoral head rotation with excessive sliding of the HFD is observed and it is often followed by cutout. The purpose of this study is to compare the ability of the three types of HFDs to prevent femoral head rotation. Methods Between July 2005 and December 2009, 206 patients aged over 60 years with trochanteric fractures who had undergone surgical treatment using a short femoral nail in our institution were enrolled into the study. We used the gamma 3 nail (GMN) as the screw-type HFD in 66 cases, the gliding nail (GLN) as a non-cylindrical blade in 76 cases, and the proximal femoral nail antirotation (PFNA) as a cylindrical blade in 64 cases. The sliding length of HFDs and the occurrence of femoral head rotation were evaluated by assessing radiographs as the main outcome, and the results were compared among these devices. Results A comparison of the degree of sliding in the GMN group showed that femoral head rotation was observed significantly more frequently in cases with rotation. Further, it appeared that femoral head rotation occurred more frequently in comminuted fractures. However, no significant differences between the sliding lengths of the different HFDs were observed among three groups. Femoral head rotation was observed in 15 cases of GMN (22.7%), 0 case of GLN, and 5 case of PFNA (7.8%). Significant differences with regard to the occurrence of femoral head rotation were observed among the three groups. Furthermore, significant differences were also observed between GLN and PFNA with respect to the occurrence of femoral head rotation. Conclusions The ability to stabilize femoral head appears to be greater with blade-type materials than with screw-type materials. Furthermore, we believe that a non-cylindrical blade is preferable to a cylindrical blade for the surgical treatment of comminuted, unstable trochanteric fractures in order to prevent femoral head rotation and cut-out.

Genetic risk score based on the prevalence of vertebral fracture in Japanese women with osteoporosis

A genetic risk score (GRS) was developed for predicting fracture risk based on the prevalence of vertebral fractures in 441 Japanese females with osteoporosis. A total of 979 (858 nonsynonymous and 121 silent) single-nucleotide polymorphisms (SNPs) located in 74 osteoporosis-susceptibility genes were genotyped and evaluated for their association with fracture prevalence. Four SNPs (protein kinase domain containing, cytoplasmic [PKDCC; rs4952590], CDK5-regulatory subunit-associated protein 1-like 1 [CDKAL1; rs4712556], wingless-type MMTV-integration site family member 16 [WNT16; rs2707466], and G-patch domain-containing gene 1 [GPATCH1; rs10416265]) showed a significant association (p < 0.05) with the fracture, in which the minor allele of the former two SNPs was the protective allele and that of the latter two SNPs was the risk allele. Applying a dominant-genetic model, we allotted − 1 point each to the protective-allele carriers and 1 point each to the risk-allele carriers, and GRS values were calculated as the sum of the points. The receiver-operating characteristic curves showed that GRS adequately predicted vertebral fracture. For the model predicted by the GRS with and without the effect of age, areas under the curves were 0.788 (95% confidence interval [CI]: 0.736–0.840) and 0.667 (95% CI: 0.599–0.735), respectively. Multiple logistic regression analysis revealed that the odds ratio for the association between fracture prevalence and GRS was 3.27 (95% CI: 1.36–7.87, p = 0.008) for scores of − 1 to 0 (n = 303) and 12.12 (95% CI: 4.19–35.07, p < 0.001) for scores of 1 to 2 (n = 35) relative to a score of − 2 (n = 103). The GRS based on the four SNPs could help identify at-risk individuals and enable implementation of preventive measures for vertebral fracture.

Incidence of tendon rupture following volar plate fixation of distal radius fractures: A survey of 2787 cases

This study assessed the comprehensive incidence of tendon rupture following volar locking plate (VLP) surgery for a large number of patients with distal radius fractures (DRFs) at multiple facilities in one prefecture, Japan. During the 4-year period, 2787 patients with DRFs underwent fixation using VLP. The overall incidence rates of rupture of the FPL, the extensor pollicis longus, the flexor digitorum profundus of the index finger, and the extensor digitorum communis were 0.35% (10 patients), 0.29% (8 patients), 0.04% (1 patient), and 0.04% (1 patient), respectively.

Hyperactivation of Nrf2 leads to hypoplasia of bone in vivo

Keap1 is a negative regulator of Nrf2, a master transcription factor that regulates cytoprotection against oxidative and electrophilic stresses. Although several studies have suggested that the Keap1‐Nrf2 system contributes to bone formation besides the maintenance of redox homeostasis, how Nrf2 hyperactivation by Keap1 deficiency affects the bone formation remains to be explored, as the Keap1‐null mice are juvenile lethal. To overcome this problem, we used viable Keap1‐deficient mice that we have generated by deleting the esophageal Nrf2 in Keap1‐null mice (NEKO mice). We found that the NEKO mice exhibit small body size and low bone density. Although nephrogenic diabetes insipidus has been observed in both the NEKO mice and renal‐specific Keap1‐deficient mice, the skeletal phenotypes are not recapitulated in the renal‐specific Keap1‐deficient mice, suggesting that the skeletal phenotype by Nrf2 hyperactivation is not related to the renal phenotype. Experiments with primary culture cells derived from Keap1‐null mice showed that differentiation of both osteoclasts and osteoblasts was attenuated, showing that impaired differentiation of osteoblasts rather than osteoclasts is responsible for bone hypoplasia caused by Nrf2 hyperactivation. Thus, we propose that the appropriate control of Nrf2 activity by Keap1 is essential for maintaining bone homeostasis.

Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field.

The safety of metallic spinal implants in magnetic resonance imaging (MRI) performed using ultrahigh fields has not been established. Hence, we examined whether the displacement forces caused by a static magnetic field and the heating induced by radiofrequency radiation are substantial for spinal implants in a 7 T field. We investigated spinal rods of various lengths and materials, a screw, and a cross‐linking bridge in accordance with the American Society for Testing and Materials guidelines. The displacement forces of the metallic implants in static 7 T and 3 T static magnetic fields were measured and compared. The temperature changes of the implants during 15‐min‐long fast spin‐echo and balanced gradient‐echo image acquisition sequences were measured in the 7 T field. The deflection angles of the metallic spinal materials in the 7 T field were 5.0–21.0° [median: 6.7°], significantly larger than those in the 3 T field (1.0–6.3° [2.2°]). Among the metallic rods, the cobalt–chrome rods had significantly larger deflection angles (17.8–21.0° [19.8°]) than the pure titanium and titanium alloy rods (5.0–7.7° [6.2°]). The temperature changes of the implants, including the cross‐linked rods, were 0.7–1.0°C [0.8°C] and 0.6–1.0°C [0.7°C] during the fast spin‐echo and balanced gradient‐echo sequences, respectively; these changes were slightly larger than those of the controls (0.4–1.1°C [0.5°C] and 0.3–0.9°C [0.6°C], respectively). All of the metallic spinal implants exhibited small displacement forces and minimal heating, indicating that MRI examinations using 7 T fields may be performed safely on patients with these implants.

Superficial Ulnar Artery Crossing Over the Palmaris Longus Tendon at the Wrist in a Cadaver: A Case Report

Superficial ulnar artery (SUA) is defined as arterial variation of an ulnar artery of high origin that lies superficially in the forearm. Because an SUA may be mistaken for a superficial vein, there is a risk of arterial damage. During routine dissection of the cadaver, we incidentally detected a case of unilateral SUA in the left arm. SUA arose from the axillary artery and descended superficial to the axillary artery and median nerve. At the wrist, the SUA crossed over palmaris longus (PL) tendon from the radial side to the ulnar side. In this cadaver, the PL tendon was located on the ulnar side and was thicker than the flexor carpi radialis tendon. Clinicians should check for the presence of SUA before any technical procedure, because lack of awareness of its presence can have serious consequences.

Evaluation of the serum ionic fluoride concentration as a biomarker of bone metabolism post-spinal fusion surgery

BACKGROUND Bone union after spinal fusion surgery with instrumentation has been determined only with imaging studies. We evaluated the usefulness of the serum ionic fluoride (SIF) concentration as a biomarker of the bone union status. METHODS We enrolled 25 patients who underwent spinal surgery in our institution, and we divided patients into three groups with and without instrumentation (G1, G2, and G3). We collected the fasting serum level preoperatively and on day 1 (D1), week 1 (D7), week 2 (D14), month 1 (D30), month 3 (D90), and month 6 (D180) postoperatively, and measured SIF concentrations using the flow injection method with an ion-selective electrode. RESULTS Although preoperative SIF concentrations were similar among the 3 groups, postoperative SIF concentrations were different among the groups. SIF concentrations in groups with instrumentation (G2 and G3) increased between D14 and D90 postoperatively and decreased at D180 postoperatively. SIF concentrations in the group without instrumentation (G1) decreased between D30 and D180 postoperatively. CONCLUSIONS An SIF concentration that is higher postoperatively than preoperatively may indicate unstable bone union, whereas a lower SIF concentration postoperatively than preoperatively may indicate stable bone union. We concluded that the SIF concentration may be useful for diagnosing bone union.

Reinvestigation of the Morphological Characteristics of the Lateral Ulnar Collateral Ligament in Humans

To clarify the cause of posterolateral rotatory instability after damage to the lateral ulnar collateral ligament (LUCL), the morphological characteristics of the LUCL were reinvestigated and three-dimensional (3D) image of the ligament was reconstructed using 35 human elbows. The results were as follows: 1) the insertion point of the LUCL on the humerus was almost at the center of the capitellum, and its width was 2.61 ± 1.02 mm. The insertion point of the LUCL on the ulna was located from the lesser sigmoid notch to the supinator crest and had a width of 9.0 ± 2.8 mm. The proximal insertion of the LUCL on the ulna was 7.0 ± 3.0 mm, and the distal part was on the articular surface of the radial head. 2) Three-dimensional imaging of the LUCL revealed an anterior curved shape that covered the radial head. Based on these results, it was clear that both the supinator crest and the lesser sigmoid notch could be useful as osseous landmarks. We think that these anatomical results are useful for surgeons performing LUCL reconstruction.

Importance of latissimus dorsi muscle preservation for shoulder function after scapulectomy

BACKGROUND Scapulectomy is an inevitable treatment for sarcomas of the scapula. This procedure is unavoidable because it reduces the local recurrence rate but can impair shoulder movements and affect the activities of daily living. This study investigated the factors influencing functional outcomes after scapulectomy. MATERIALS AND METHODS The clinical results of 8 patients (5 males, 3 females) who were diagnosed with primary or metastatic sarcomas of the scapula were retrospectively reviewed. The mean age was 49 years (range, 11-86 years). We examined the correlation between the type of excision of the scapula (total, subtotal, or partial) and postoperative functional outcomes according to the Musculoskeletal Tumor Society (MSTS) score. In partial excision, the glenohumeral joint was preserved; in subtotal excision, the glenoid was completely resected and some bony components were preserved; and in total excision, the entire bony component of the scapula was resected. The average follow-up period was 55 months (range, 9-142 months). RESULTS The partial, subtotal, and total excision groups had mean functional scores of 96.7%, 76.7%, and 62.2%, respectively. Although the mean functional scores were lower in patients who underwent total and subtotal excisions, 3 patients in whom the latissimus dorsi muscle was preserved had better function (mean MSTS score, 76.7%) than the 2 patients in whom it was not preserved (mean MSTS score, 55.0%). CONCLUSION These results suggest that the latissimus dorsi muscle, along with the deltoid and pectoralis major muscles, is one of the stabilizers of the proximal humerus after scapulectomy.