Yuji Tomori

Transverse Ultrasound Assessment of the Displacement of the Median Nerve in the Carpal Tunnel during Wrist and Finger Motion in Healthy Volunteers

PURPOSE The purpose of this study was to investigate the displacement of the median nerve in the carpal tunnel during finger motion at varied wrist positions using transverse ultrasound in healthy volunteers, in order to clarify the appropriate position of a wrist splint in treating carpal tunnel syndrome. METHODS Fifty wrists of 25 asymptomatic volunteers were evaluated by transverse ultrasound. The location of the median nerve in the carpal tunnel was examined at 5 wrist positions (neutral, 60° dorsiflexion, 60° palmar flexion, 40° ulnar flexion, 10° radial flexion) with all 5 fingers in full extension, all 5 fingers in full flexion, and isolated thumb in full flexion, respectively. RESULTS The median nerve was located significantly (p<0.05) more dorsally at the wrist dorsal flexion position, more ulnopalmarly at the wrist palmar flexion position, more radially at the wrist radial flexion position, and more radially at the wrist ulnar flexion position than at the wrist neutral position in all 5 fingers at full extension. The median nerve moved the most significantly dorsally among all wrist positions during finger motion at the wrist dorsal flexion position (p<0.05). Conversely, the median nerve moved the most significantly ulnopalmarly at the wrist palmar flexion position with all 5 fingers in full flexion among all wrist positions during finger motion (p<0.05). This latter wrist and finger position induced significant displacement of the median nerve toward the transverse carpal ligament, and compressed it between the flexor tendons and the transverse carpal ligament. CONCLUSIONS This study showed that there is a significant relationship between the median nerve displacement in the carpal tunnel and the motion of the wrist and fingers. This finding suggests that the compression or the shearing stress of the median nerve caused by the movement of the flexor tendons is reduced in the wrist dorsal flexion position compared with other wrist positions. This wrist dorsal flexion position could be the appropriate position for a wrist splint in the treatment for carpal tunnel syndrome. This ultrasound information provides further knowledge and understanding of the biomechanics and pathophysiology of the carpal tunnel. It could also help in the accurate analysis and assessment of diagnostic images and treatment for carpal tunnel syndrome.

Transverse Movement of the Median Nerve in the Carpal Tunnel during Wrist and Finger Motion in Patients with Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral compression neuropathy of the upper extremity. Repetitive wrist and finger motion has been suggested as a major factor of pathogenesis of CTS. However, little is known about the pathomechanics of CTS. We aimed to evaluate the movement of the median nerve in the carpal tunnel during wrist and finger motions using transverse ultrasound in 21 patients with CTS (5 men and 16 women with mean age 69.0 years). We examined quantitatively the median nerve location as a coordinate within the carpal tunnel at varied wrist positions with all fingers full extension and flexion respectively in the affected and unaffected sides. We thus found that at all wrist positions during finger motion, the median nerve moved significantly more ulnopalmarly in the affected side compared to the unaffected side (p < 0.05). Especially, at the wrist palmar-flexion position as a provocative test, the nerve moved significantly (p < 0.05) the most ulnopalmarly among all wrist positions in the affected side. The nerve was the most strongly compressed against the transverse carpal ligament by the flexor tendons. Additionally, the displacement amount of the nerve in the dorsal-palmar direction was significantly smaller in the affected side than in the unaffected side. These findings indicate that such a pattern of nerve movement has the potential to distinguish affected from unaffected individuals. This ultrasound information could be useful in better understanding of the pathomechanics of CTS, and in further improvement of diagnosis and treatment for CTS.

Ultrasound Evaluation of the Transverse Movement of the Flexor Pollicis Longus Tendon on the Distal Radius during Wrist and Finger Motion in Healthy Volunteers.

PURPOSE This study aimed to evaluate the kinematics of the flexor pollicis longus tendon (FPL) at the wrist by examining the movement of the FPL on the distal radius during various wrist and finger motions using transverse ultrasound in healthy volunteers. METHODS Forty-eight wrists of 24 asymptomatic volunteers were examined by transverse ultrasound to observe the location of the FPL on the distal radius at 5 wrist positions (neutral, 60° dorsal flexion, 60° palmar flexion, 40° ulnar deviation, and 10° radial deviation) with all 5 fingers in full extension and full flexion, and isolated thumb in full flexion, respectively. RESULTS We found that the FPL was situated statistically significantly more ulnodorsally at the wrist dorsal and ulnar deviation positions, more ulnopalmarly at the wrist palmar flexion position, and more radiopalmarly at the wrist radial deviation-position than at the wrist neutral position with all 5 fingers at full extension. Especially, it moved statistically significantly most ulnodorsally at the wrist dorsal flexion position during finger motion. The FPL moved most statistically significantly ulnopalmarly at the wrist palmar flexion position with all 5 fingers in full extension among all wrist positions during finger motion. During finger motion, the wrist dorsal flexion position induced significant displacement of the FPL to the distal radius and compressed it between the flexor tendons and the distal radius. The average distance between the FPL and the volar surface of the distal radius in the palmar-dorsal direction at wrist dorsal flexion position in all fingers at full flexion was 1.9 mm, the smallest among all wrist positions during finger motion. CONCLUSIONS There is a significant relationship between the transverse movement of the FPL at the distal radius and wrist and finger motions. Our findings indicated that the irritation of the FPL caused by the movement of both the FPL itself and of the flexor digitorum superficialis and profundus is most induced with the wrist in dorsal flexion with all 5 fingers at full flexion compared to other wrist positions during finger motion. This wrist position might be the optimum one at which to evaluate the irritation of the FPL from volar locking plates in patients with distal radius fracture. We believe that our transverse ultrasound results can play a role in the gaining of a better understanding of the kinematics of the FPL. Moreover, they have potential to lead to improved diagnosis of and treatment for fractures of the distal radius and help to minimize the risk of FPL rupture related to volar locking plates.

Morphological Analysis of Trafficking and Processing of Anionic and Cationic Liposomes in Cultured Cells

Liposomes, artificial phospholipid vesicles, have been developed as a non-viral drug delivery system to allow contained agents to be efficiently delivered to target sites via systemic circulation. Liposomes have been used as a gene transfer tool with cultured cells; however, their precise trafficking and processing remain uncertain. Furthermore, liposomes with different surface charges are known to exhibit distinct properties. The purpose of the current study was to elucidate the intracellular trafficking and processing of liposomes with anionic and cationic surface charges from a morphological view point. We found that cationic liposomes (CLs) were more effectively taken by the cells than anionic liposomes (ALs). Confocal laser scanning microscopy and transmission electron microscopy demonstrated distinct intracellular localization and processing patterns of ALs and CLs. ALs and their contents were localized in lysosomes but not in cytosol, indicating that ALs are subjected to the endosome-lysosome system. In contrast, contents of CLs were distributed mainly in the cytosol. CLs appear to disturb the cell membrane and then collapse to release their contents into the cytosol. It is feasible that the contents of CLs enter the cytosol directly rather than via the endosome-lysosome system.

Kisspeptin expression is decreased in the arcuate nucleus of hypothyroid female rats with irregular estrus cycles

Insufficiency of thyroid hormones inhibits gonadotropin release and results in dysregulation of reproductive function, although the precise mechanism of this disrupted gonadotropin secretion remains unclear. Kisspeptin is a neuropeptide that strongly stimulates gonadotropin secretion and plays an important role in reproductive function. To examine the involvement of kisspeptin in the dysregulation of gonadotropin secretion in hypothyroidism, we investigated Kiss1 mRNA expression and kisspeptin immunoreactivity in the hypothalamus of female rats treated with propylthiouracil (PTU). In the PTU-treated rats, serum thyroxine (T4) was significantly decreased, whereas thyroid stimulating hormone (TSH) levels were significantly increased. In addition, irregular estrus cycles were observed in PTU-treated rats. In situ hybridization and immunohistochemistry revealed significant reductions in the number of Kiss1 mRNA-expressing neurons and kisspeptin-immunoreactive neurons in the arcuate nucleus (ARC) but not in the anteroventral periventricular nucleus (AVPV) of the PTU-treated rats. Although the serum levels of luteinizing hormone (LH) and estradiol (E2) were unaffected, serum prolactin levels were significantly increased after PTU treatment. These data indicate that kisspeptin expression in the ARC is suppressed under thyroid hormone insufficiency, suggesting that the dysregulation of reproductive function in hypothyroidism is caused by inhibition of kisspeptin neurons in the ARC.

Color Doppler ultrasound assessment for identifying perforator arteries of the second dorsal metacarpal flap

Purpose: The second dorsal metacarpal (SDMC) perforator flap has been widely used for the soft tissue reconstruction of the hand. However, it is difficult to identify the depth and branches of the perforators of the second dorsal metacarpal artery (SDMA) using only handheld acoustic Doppler flowmetry (HADF), which is the most common method. The purpose of this study was to compare the results of examination by color Doppler ultrasonography (CDU) with those of HADF and to evaluate the efficacy of CDU for detection of the perforators to be used in the design of the SDMC flap. Methods: Twenty-two healthy volunteers (42 hands) were examined using both CDU and HADF. All locations identified as the perforators of the SDMA by the two examinations were mapped respectively. Results: The total perforator arteries detected with CDU in all hands were 111 branches, 49 branches of which could not be identified with HADF. The average number of perforators of the SDMA per hand found with CDU was 2.8 branches, while that for HADF was only 1.8 branches. The detection rates of the cutaneous perforators of the SDMA by CDU were 100% in the proximal one-third of the second metacarpal and 95% in the distal one-fourth of the second metacarpal. Conclusion: This study demonstrated the superiority of CDU compared with HADF for detection of the perforators of the SDMA. The CDU examination could easily identify the locations of the cutaneous perforators and help in the useful assessment of vascularity for the SDMC flap.

Three-dimensional dynamic motion analysis of the first carpometacarpal ligaments

Purpose: The purpose of this study was to analyze the dynamic motion of the first carpometacarpal (CMC) ligaments on a three-dimensional (3-D) surface model and to examine the changes in the ligament lengths during the motion of the first CMC joint. Methods: Six fresh-frozen cadaver wrists were used to analyze the motion of the first CMC ligaments on a 3-D coordinate system using a digitizer. Four ligaments, namely, dorsoradial ligament (DRL), posterior oblique ligament (POL), superficial anterior oblique ligament (SAOL), and deep anterior oblique ligament (dAOL), were dissected and identified. Their attachments were digitized and represented on 3-D bone images. The distances between the ligament attachments of the first metacarpal and the trapezium, which were the ligament lengths, were measured during the extension–flexion and adduction–abduction of the first CMC joint. Results: Both the DRL and POL lengthened during flexion of the first CMC joint, and both the SAOL and dAOL lengthened during extension. Both the DRL and SAOL lengthened during adduction, and both the POL and dAOL lengthened during abduction. The DRL alone lengthened significantly at flexion and adduction when the first CMC joint was in dorsoradial dislocation. Conclusions: The lengths of four ligaments changed significantly during first CMC joint motion. This study suggested that the DRL contributes substantial stability to the first CMC joint, preventing dorsoradial dislocation. This 3-D information improves the knowledge and understanding of the function of individual ligaments and their roles in the stability of the first CMC joint.

Florid reactive periostitis in the fifth phalange of a professional boxer: A case report.

Rationale:Florid reactive periostitis is a rare, benign bone and chondrogenic lesion that develops most frequently in the phalanges of the hands. Although the definitive cause of florid reactive periostitis is unknown, the major inciting factor is generally considered to be trauma, including repetitive minor trauma. Patient concerns:We present a case of florid reactive periostitis affecting two contiguous phalangeal bones of the left fifth phalange of a 23-year-old male professional boxer. The patient had experienced chronic pain around the metacarpophalangeal joint of the left fifth phalange when punching with the left hand; this pain was improved but not resolved after conservative treatment. Interventions:Plain radiography of the fifth phalange revealed a bulging bone lesion on the volar side of the proximal phalanx and metacarpal of the left fifth phalange. Computed tomography also showed raised bony lesions on the volar side of these bones without bony destruction or intraregional calcification. Surgery was performed and histopathology revealed that the bone specimens comprised a mixture of fibrous connective tissue and relatively immature bone covered by bland osteoblasts. Diagnoses:These findings were suggestive of a benign bone formation process, and the lesion was diagnosed as florid reactive periostitis. Outcomes:The pain and tenderness in the left fifth phalange experienced during boxing had completely resolved by 6 months postoperatively, and 12 years postoperatively the patient had full range of motion and no recurrence of pain. Lessons:Traction force, such as those associated with “leading jabs,” may induce repetitive minor trauma and subsequent periosteal damage, resulting in the gradual development of bulging bone ridges on the volar surface of the proximal fifth phalange and metacarpus of the hand.

Three-dimensional Analysis of the Attachment and Path of the Transverse Carpal Ligament

PURPOSE The purpose of this study was to describe and evaluate the detailed anatomic locations and areas of ligamentous attachments and paths of the transverse carpal ligament (TCL) on a three-dimensional (3-D) surface model. METHODS Ten fresh-frozen cadaver wrists were used to dissect and identify the TCL. Their ligament attachments and whole bone surfaces were digitized three-dimensionally and their areas evaluated. The attachments of each ligament were represented in a model combining CT surfaces overlaid by a digitized 3-D surface, and were also visually depicted with a different color for each on 3-D images of the bones. RESULTS The TCL was found to be composed of two or three discrete ligaments. Both the trapezium-hook of hamate ligament and the trapezium-pisiform ligament were identified in all ten specimens. The scaphoid-pisiform ligament was found in only two of the ten specimens. The average areas of the attachments of the TCL were 42.7 mm(2) on the trapezium, 30.0 mm(2) on the hook of hamate, 21.6 mm(2) on the pisiform, and 12.7 mm(2) on the scaphoid. CONCLUSIONS The anatomic 3-D attachment sites of the TCL were visually shown qualitatively, and their areas quantified. This 3-D information offers further knowledge and understanding of the anatomy and biomechanics of the TCL. It could also help in the accurate assessment of radiographic images and treatment of various wrist injuries and diseases when performing such procedures as carpal tunnel release, Guyons canal release, trapeziectomy, hook of hamate excision, or arthroscopy.

Minimally invasive modified Camitz opponensplasty for severe carpal tunnel syndrome

Purpose: We aimed to compare the clinical results and the complications between the minimally invasive modified Camitz opponensplasty and the conventional Camitz opponensplasty for severe carpal tunnel syndrome (CTS), and to evaluate the efficacy of the modified technique for CTS. Methods: Twenty-eight hands in 24 patients with severe CTS who had disorder of the thumb opposition with thenar muscle atrophy (group 1) were treated by minimally invasive modified Camitz opponensplasty, passing the transferred palmaris longus (PL) tendon under the abductor pollicis brevis (APB) fascia using only palm and thumb incision, and no incision to either wrist crease or forearm. Ten hands in 10 patients (group 2) were treated by the conventional Camitz opponensplasty. Clinical evaluation was made by comparing the results before and after surgery for the angle of the thumb palmar abduction, pinch power, and grip strength. Results: All clinical findings significantly improved after surgery compared with before surgery in all patients. In group 1, there were no complications including transferred tendon bowstring, painful wrist scar, or injury to the palmar cutaneous branch of the median nerve in all hands. Conversely, patients in group 2 had four painful wrist scars and nine bowstrings of the transferred tendon. Conclusions: Several complications have been considered to attribute to the long incision and an extensive dissection crossing the wrist crease from the palm to the wrist in the conventional Camitz procedure. The current modified Camitz opponensplasty by minimally invasive incision without straddling the wrist crease is a simple and effective procedure that can decrease the risk of painful scar around the wrist crease in severe CTS patients with disorder of thumb opposition. Additionally, this technique, by passing the transferred PL tendon under the APB fascia, is useful in restoring the thumb opposition immediately, and in preventing the bowstringing of the transferred tendon.