鈴木 崇根

Cadaver surgical training (CST), which ensures medical safety by improving the skills of surgeons, is popular overseas. However, training involves ethical issues given the use of cadavers. In 2012, the Japan Surgical Society and the Japanese Association of Anatomists compiled and opened the "Guidelines for Cadaver Dissection in Education and Research of Clinical Medicine (Guideline 2012)" to the public. This has allowed Japan to conduct CST or research under the regulations of Postmortem Examination and Corpse Preservation Act and the Body Donation Act. However, its dissemination has been sluggish. The Clinical Anatomy Lab (CAL), established in 2010 at Chiba University, is a facility for conducting CST and research. In the 11 years since its inception, 250 programs have been implemented. Orthopedics had the most implemented in the clinical field, with 120 (48%), followed by emergency and critical care medicine with 27 (10.8%), and neurological surgery with 27 (10. 8%). Based on the purpose of the training, the most common objective for the programs (approximately 83%) was education. Further, the highest number of programs was recorded in 2018 (34) and participants in 2017 (631). The implementation of CST requires more than just guiding surgeons to a dissection practice room. There are several methods of preserving cadavers to make them suitable for CST. For various surgical simulations, an operating table is more suitable than a dissection table. The current paper provides information on how to implement CST in universities that have so far only worked on anatomy education for medical students.

This article translates the guidelines for cadaver surgical training (CST) published in 2012 by Japan Surgical Society (JSS) and Japanese Association of Anatomists from Japanese to English. These guidelines are based on Japanese laws and enable the usage of donated cadavers for CST and clinical research. The following are the conditions to implement the activities outlined in the guidelines. The aim is to improve medicine and to contribute to social welfare. Activities should only be carried out at medical or dental universities under the centralized control by the department of anatomy under the regulation of Japanese law. Upon the usage of cadavers, registered donors must provide a written informed-consent for their body to be used for CST and other activities of clinical medicine. Commercial use of cadavers and profit-based CST is strongly prohibited. Moreover, all the cadaver-related activities except for the commercial-based ones require the approval of the University's Institutional Review Board (IRB) before implementation. The expert committee organized at each university for the implementation of CST should summarize the implementation of the program and report the details of the training program, operating costs, and conflicts of interest to the CST Promotion Committee of JSS.

This article translates the guidelines for cadaver surgical training (CST) published in 2012 by Japan Surgical Society (JSS) and Japanese Association of Anatomists from Japanese to English. These guidelines are based on Japanese laws and enable the usage of donated cadavers for CST and clinical research. The following are the conditions to implement the activities outlined in the guidelines. The aim is to improve medicine and to contribute to social welfare. Activities should only be carried out at medical or dental universities under the centralized control by the department of anatomy under the regulation of Japanese law. Upon the usage of cadavers, registered donors must provide a written informed-consent for their body to be used for CST and other activities of clinical medicine. Commercial use of cadavers and profit-based CST is strongly prohibited. Moreover, all the cadaver-related activities except for the commercial-based ones require the approval of the University's Institutional Review Board (IRB) before implementation. The expert committee organized at each university for the implementation of CST should summarize the implementation of the program and report the details of the training program, operating costs, and conflicts of interest to the CST Promotion Committee of JSS.

Resistance of de Quervain's disease to conservative treatment has been associated with an intertendinous septum in the first compartment. This study aimed to investigate the relationship between intertendinous septum's presence or absence, internal pressure and wrist positon in the first compartment. Fourteen arms were obtained from seven fresh frozen cadavers. A pressure sensor was inserted into the first compartment; if a septum was present, the pressure sensor was inserted into the abductor pollicis longus (APL) side and the extensor pollicis brevis (EPB) side, respectively. Three wrist positions were also tested: neutral, 45° flexion, and 45° extension. Intertendinous septa were present in seven wrists. The average pressure change in the first compartment measured on the EPB side of a present septum was significantly greater than that measured on the APL side of a present septum or where no septum existed: no septum = 54.6 ± 48.3 kPa; septum, EPB = 81.7 ± 76.5 kPa; and septum, APL = 32.8 ± 37.4 kPa. The average pressure change was also significantly greater in the flexion wrist position relative to the neutral and extension positions: neutral = 36.3 ± 58.0 kPa; 45° flexion = 79.5 ± 65.9 kPa; and 45° extension = 50.4 ± 42.6 kPa. Clear relationships existed between (1) the presence of a septum and increased internal pressure on the EPB side in the first compartment and (2) increased internal pressure with the wrist at 45° flexion compared with the neutral and extension position.

Purpose: To determine the optimal timing of plate removal in patients with forearm diaphyseal fractures fixed with a locking plate via the analysis of bone atrophy over time. Methods: The study subject was a 56-year-old man. Computed tomography was performed at 0.5, 1, 1.5, 2, 3, 4, and 5 years after plate fixation. Finite element analysis was performed to measure the fracture load of the radius and ulna. The fracture loads of the affected and healthy sides were compared, and their ratio was calculated by dividing the value of the affected side by that of the healthy side at each time point. Results: The strength of the radius and ulna was 40.9% and 29.3%, respectively, on the healthy side at 1 year after surgery. The fracture load increased from the second to the third postoperative year; the strength of the radius and ulna was 62.2% and 37.3%, respectively, on the healthy side after the third year. However, after the third year, the fracture load declined and reached 38.8% and 18.9% for the radius and ulna, respectively, on the healthy side by the fifth postoperative year. Conclusions: The long-term fixation of forearm diaphyseal fractures using a locking plate leads to progressive bone atrophy. Future bone atrophy during long-term locking plate fixation without removal should be monitored. Type of study/level of evidence: Therapeutic IV.

Purpose: The triangular fibrocartilage complex (TFCC) serves to stabilize the distal radioulnar joint, but the stress distribution within the TFCC under dynamic loading is unknown. Finite element analysis (FEM) can be used to investigate the stress distribution, but its accuracy depends on knowing the material properties of the TFCC. The aim of this study was to evaluate the material properties of the TFCC using cadaveric specimens. Methods: We obtained 12 upper limbs (6 right and 6 left) from 6 fresh-frozen cadavers (3 women and 3 men). Average age at death was 78.3 years (range, 69-87 years). Using a dorsal approach, we dissected each component of the TFCC. We performed tensile and compressive testing with a mechanical testing machine. Young's modulus was calculated from the slope of the linear part of the stress-strain curve. Results: The Young's modulus was 7.0 ± 2.4 MPa in the volar component, 8.7 ± 2.3 MPa in the ulnar component, 5.4 ± 1.7 MPa in the dorsal component, 6.1 ± 3.3 MPa in the fibers of the fovea, and 8.1 ± 1.2 MPa in the articular disc. Conclusions: The Young's modulus of each component was about 5 to 9 MPa. Specimens used in this study were from elderly individuals, and care must be taken when using these values for FEM. Clinical relevance: These data will be used to perform FEM to predict the mechanical behavior of the ulnar side of the wrist and the stress distribution applied to the TFCC, the distal radioulnar joint, and the ulnar head.

As fractures heal, immature callus formed in the hematoma is calcified by osteoblasts and altered to mature bone. Although the bone strength in the fracture-healing process cannot be objectively measured in clinical settings, bone strength can be predicted by specimen-specific finite element modeling (FEM) of quantitative computed tomography (qCT) scans. FEM predictions of callus strength would enable an objective treatment plan. The present study establishes an equation that converts material properties to bone density and proposes a specimen-specific FEM. In 10 male New Zealand white rabbits, a 10-mm long bone defect was created in the center of the femur and fixed by an external fixator. The callus formed in the defect was extracted after 3-6 weeks, and formed into a (5 × 5 × 5 mm3) cube. The bone density measured by qCT was related to the Young's modulus and the yield stress measured with a mechanical tester. For validation, a 10-mm long bone defect was created in the central femurs of another six New Zealand white rabbits, and fixed by an external fixator. At 3, 4, and 5 weeks, the femur was removed and subjected to Computed tomography (CT) scanning and mechanical testing. A specimen-specific finite element model was created from the CT data. Finally, the bone strength was measured and compared with the experimental value. The bone mineral density σ was significantly and nonlinearly correlated with both the Young's modulus E and the yield stress σ. The material-property conversion equations were E = 0.2391e8.00ρ and ρ = 30.49σ2.41. Moreover, the experimental bone strength was significantly linearly correlated with the prospective FEM. We demonstrated the Young's moduli and yield stresses for different bone densities, enabling a FEM of the bone-healing process. An FEM based on these material properties is expected to yield objective clinical judgment criteria.

INTRODUCTION: An abnormal distal insertion of the extensor pollicis brevis (EPB) tendon into the thumb interphalangeal joint (IP) has been observed in refractory cases of de Quervain's disease. This is associated with the extensor being wider at the midpoint of the proximal phalanx; however, there is no method to noninvasively measure this. This study evaluated the accuracy of measuring the extensor width using ultrasonography, to establish a noninvasive method for predicting an EPB extending the IP insertion. MATERIALS AND METHODS: Of 23 arms from 12 fresh frozen cadavers, the extensor tendon width at the midpoint of the proximal phalanx was measured using ultrasonography and directly at dissection. The association between these values was evaluated using correlation analysis. A cut-off value of extensor tendon width was obtained using receiver operating characteristic analysis. RESULTS: A strong correlation was observed between the ultrasonography and the measured values. The EPB tendons were normal in 13 arms (57%) and extended in 10 (43%), with a significant difference between these groups in the mean width of the extensor tendon (6.8 ± 1.1 vs. 8.4 ± 1.0 mm). A cut-off extensor tendon width of 8.0 mm yielded an EPB extending the IP. CONCLUSION: An EPB extending the IP tendon can be predicted by measuring the extensor tendon width at the midpoint of the proximal phalanx using ultrasonography. The cut-off tendon width value of ≥ 8.0 mm may be useful for assessments prior to surgery and for conservative care.

Introduction: The extensor pollicis brevis (EPB) tendon normally inserts into the base of the proximal phalanx of the thumb. However, a distal insertion of the EPB tendon into the thumb interphalangeal joint has been reported in refractory cases of de Quervain’s disease. We hypothesized that the EPB tendon is wider beyond the thumb metacarpophalangeal joint in patients with extended EPB. This study aimed to evaluate the relationship between the extensor tendon width and the point of distal insertion of the EPB tendon. Materials and methods: In 45 hands from 18 male and 27 female adult cadavers, the first extensor compartment was dissected and the existence of the intertendinous septum was assessed. The extensor tendon width was measured at the midpoint of the proximal phalanx, and relationships between extended EPB tendon, existence rate of the intertendinous septum, sex, and extensor tendon width were examined. Results: Of 45 cases, intertendinous septum and extended EPB tendon were observed in 37 (82.2%) and 23 (51.1%), respectively. There was no significant difference between the existence rates of both these factors and sex. The mean extensor tendon width in the extended EPB group was significantly greater than in the normal EPB group. The cut-off value of extensor tendon width in the extended EPB group was 7.12 mm. Conclusions: The extensor tendon width was wider in the extended EPB group than in the normal EPB group, suggesting that the differences in the EPB tendon width can be used to identify various anatomical variations in extended EPB.

解剖学は、ヒトの病状変化や疾患の有無を診る看護師などさまざまな医療専門職の教育で必要とされる基礎科目である。加えて、生物学と共に医療にとって不可欠な基礎科目であり、上記の専門職のための国家試験にも出題される。しかし、人体の基本構造を知るという点で非常に近い高校の生物学の知識の定着が十分でない学生もいる上、生物学を履修せずに物理・化学で受験した学生もおり、その知識には学生間で大きな隔たりがある。筆頭著者は看護師養成大学において、解剖学・生物学の講義を担当してきた。その経験からガニェ9教授事象を参考にして、入学者のレディネスに合わせ、看護師養成大学の実情に合ったカリキュラムと授業を取り入れた。さらに、毎回小テストを行い、補習や個別指導を実施することにより、専門科目に対応できる学力を定着させることが出来た。解剖学の学期末の期末試験の成績では全体平均点87.3(SD11.0、中央値81.0)と高得点であった。ここでは筆者らの解剖学での取り組みを中心に紹介する。(著者抄録)

PURPOSE: Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. METHODS: In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. RESULTS: Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. CONCLUSIONS: This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Background: The extensile extensor digitorum communis (EDC) splitting approach can access the ulnar coronoid process (UCP), which can be used to treat terrible triad injuries. The present study anatomically examined the extensile EDC splitting approach for exposing the UCP. Methods: Twenty fresh frozen cadaveric upper limbs were dissected. The splitting length of the EDC and detachment length of the extensor carpi radialis brevis (ECRB)–extensor carpi radialis longus (ECRL)–brachioradialis (BR) origin were measured to expose the UCP. The distance between the most distal site of the EDC splitting and the point at which the posterior interosseous nerve (PIN) crosses the anterior aspect of the radial shaft, and the distance between the most proximal site of the ECRB-ECRL-BR origin detachment and the point at which the radial nerve crosses the anterior aspect of the humeral shaft were measured. Results: The splitting length of the EDC was 45.4 ± 4.8 mm, the detachment length of the ECRB-ECRL-BR origin was 30.2 ± 4.7 mm, the distance between the distal site of the EDC splitting and PIN was 10.6 ± 6.1 mm (minimum distance, 1.1 mm), and the distance between the proximal site of the ECRB-ECRL-BR origin detachment and the radial nerve was 49.5 ± 9.7 mm (minimum distance, 31.7 mm). Conclusions: The extensile EDC splitting approach can sufficiently expose the UCP. However, splitting must be performed carefully because the most distal site of the EDC splitting is close to the point at which the PIN crosses the anterior aspect of the radial shaft (average distance, 10 mm minimum distance, 1 mm).

Purpose To measure distances from anatomical landmarks to the median nerve, and estimate the length of the flexor-pronator/flexor carpi ulnaris (FCU) detachment necessary to expose the anteromedial facet of the ulnar coronoid process (UCP) using the Hotchkiss over-the-top approach. Methods Dissections were made of 20 fresh-frozen cadaveric upper limbs. Measurements were made of the shortest distance from the medial epicondyle to the median nerve, the distance from the medial epicondyle to the median nerve in line with the flexor-pronator/FCU interval, the shortest distance from the apex of the UCP to the median nerve, and the length of the flexor-pronator/FCU detachment necessary to expose the anteromedial facet of the UCP. Measurements were also made of the length of the ulnar insertion of the brachialis muscle and the shortest distances from the proximal and distal insertions of the brachialis muscle to the median nerve. Results The distances and lengths were as follows: medial epicondyle to median nerve, 31 ± 3 mm in line with the flexor-pronator/FCU interval, 43 ± 5 mm from the apex of the UCP to the median nerve, 7 ± 2 mm the detachment necessary to expose the UCP, 47 ± 6 mm the ulnar insertion of the brachialis muscle, 27 ± 4 mm and the proximal and distal insertions of the brachialis muscle to the median nerve, 14 ± 2 mm and 5 ± 1 mm, respectively. Conclusions The length of the flexor-pronator/FCU detachment necessary to expose the anteromedial facet of the UCP was similar to the distance from the medial epicondyle to the median nerve in line with the flexor-pronator/FCU interval. The distance from the distal insertion of the brachialis muscle to the median nerve was 5 mm. Clinical relevance The results of our study provide information on important points for surgeons to consider when performing distal exposure using the Hotchkiss over-the-top approach.

Purpose To assess the anatomic feasibility of a median-to-radial nerve transfer in cadaver limbs and to quantify the number of axons present in the cut ends of the involved donor and recipient nerves. Methods Ten fresh frozen cadaveric upper limbs were dissected. We investigated whether the flexor carpi radialis (FCR) branch/flexor digitorum superficialis (FDS) branch (donor nerve) reached the posterior interosseous nerve (PIN)/extensor carpi radialis brevis (ECRB) branch (recipient nerve) without tension. We also investigated the length of the transected supinator fascia for FCR-posterior interosseous nerve transfer and the FDS-ECRB positional relationship using the epicondyle line and the midline of the forearm as axes. The findings were used for these 2 types of nerve transfer with evaluation closer to the target muscles. The distance between the point at which the FDS and ECRB branches met and the point at which the ECRB branch entered the muscle was measured. After nerve coaptation, the axon number was determined by histological evaluation. Results In all limbs, the FCR and FDS branches reached the PIN and the ECRB branch without tension. The transected supinator fascia was 17 (3-25) mm long. The distance between the FDS and ECRB branches was 48 (23-65) mm distal to the epicondyle line and approximately 23 (18-27) mm radial to the midline of the forearm. The distance between the point at which the FDS and ECRB branches met and the point at which the ECRB branch entered the muscle was 27 (17-40) mm. The mean axon numbers were FCR, 1501 (932-3022) PIN, 5162 (4325-7732) FDS, 885 (558-962) and ECRB, 548 (433-723). Conclusions The FCR branch could be transferred to the PIN branch and the FDS to the ECRB branch in all limbs without tension. Clinical relevance We provide anatomical and histological information for median-to-radial nerve transfer.

Purpose To compare the mechanical properties of sliding lengthening (SL) and Z-lengthening (ZL) for flexor tendon elongation used for conditions such as Volkmann contracture, cerebral palsy, and poststroke spasticity. Methods We harvested 56 flexor tendons, including flexor pollicis longus tendons, flexor digitorum superficialis tendons (zones II to IV), and flexor digitorum profundus tendons (zones II to V) from 24 upper limbs of 12 fresh cadavers. Each tendon was harvested together with its homonymous tendon from the opposite side of the cadaver and paired. We used 28 pairs of tendons and divided them randomly into 4 groups depending on the lengthening distance (20 or 30 mm) and type of stitching (single or double mattress sutures). Then we divided each pair into either the SL or ZL group. Each group was composed of 7 specimens. The same surgeon lengthened all tendons and stitched them with 2-0 polyester sutures. We tested biomechanical tensile strength immediately after completing lengthening and suturing in each group. Results Ultimate tensile strengths were: 23 N for the SL 20-mm lengthening and single mattress suture and 7 N for the ZL 25 N for the SL 20-mm lengthening and double mattress suture and 10 N for the ZL 15 N for the SL 30-mm lengthening and single mattress suture and 8 N for the ZL and 18 N for the SL 30-mm lengthening and double mattress suture and 10 N for the ZL. Conclusions The SL technique may be a good alternative to the ZL technique because it provides higher ultimate tensile strength. Clinical relevance Because of its higher ultimate tensile strength, the SL technique may allow for earlier rehabilitation and reduced risk of postoperative complications.

We conducted an anatomical study to determine the best technique for transfer of the anterior interosseous nerve (AIN) for the treatment of proximal ulnar nerve injuries. The AIN, ulnar nerve, and associated branches were dissected in 24 cadaver arms. The number of branches of the AIN and length available for transfer were measured. The nerve was divided just proximal to its termination in pronator quadratus and transferred to the ulnar nerve through the shortest available route. Separation of the deep and superficial branches of the ulnar nerve by blunt dissection alone, was also assessed. The mean number of AIN branches was 4.8 (3 to 8) and the mean length of the nerve available for transfer was 72 mm (41 to 106). The transferred nerve reached the ulnar nerve most distally when placed dorsal to flexor digitorum profundus (FDP). We therefore conclude that the AIN should be passed dorsal to FDP, and that the deep and superficial branches of the ulnar nerve require approximately 30 mm of blunt dissection and 20 mm of sharp dissection from the point of bifurcation to the site of the anastomosis. The use of this technique for transfer of the AIN should improve the outcome for patients with proximal ulnar nerve injuries.

The aim of this study was to investigate the correlation of wrist extension strength (WES) and grip strength (GS) using a radial nerve block, and to determine the WES required to prevent the "wrist flexion phenomenon" (antagonistic WES) when making a fist. We tested 14 arms in seven healthy males. WES and GS were measured before blocking as standard WES and standard GS. All participants then had radial nerve blocks with mepivacaine hydrochloride. During the recovery process from radial nerve blockade, WES and GS were recorded every 5 minutes. There was a very strong correlation between WES and GS (p &lt 0.0001). The mean antagonistic WES was 51% of standard WES, and the mean GS, recorded at the same time, was 66% of standard GS. © The Author(s) 2012.