Flexor Digitorum Superficialis Research Articles

Three in one - unusual palmaris longus muscle anatomical variation.

The palmaris longus muscle (PLM) is one of the most variable muscles in human body, pre-senting a wide range of morphological variants such as reversed course, biventer muscle, bi-furcated tendon or total agenesis. Their clinical impact is particularly important in diagnosis and treatment of carpal tunnel syndrome and reconstructive surgery. We present a case of PLM including a previously undescribed combination of variations. A routine dissection of male cadaver aged approximately 60 demonstrated a biventer muscle, with superior and inferior belly being interrupted by a long tendon. The inferior belly passed deep to the flexor retinaculum and its terminal tendon connected to flexor digitorum superfi-cialis tendon for 5th finger. The clinical importance of variations found have been described separately, including unsuita-bility of biventer muscles for tendon reconstruction and increased risk for developing carpal tunnel syndrome in patients with PLM tendon passing deep to the flexor retinaculum. In conclusion, as another variation of PLM is described, it is crucial to bear in mind the poten-tial morphological types of the muscle in diagnosis and treatment of patients, especially in surgery of the hand and forearm.

A transmuscular path of the medial branch of the high division of the median nerve: an anatomical variation of clinical and surgical importance

The median nerve (MN) is a mixed nerve formed in the brachial plexus, which innervates a large part of the upper limb. It presents several variations in its trajectory, resulting in many pathologies and iatrogenic surgical compromises. This report highlights a transmuscular route of the medial branch of the upper division of the MN, which to date does not fit into the classifications described in the literature on MN variations. Knowledge of this high division of the MN, as well as its transfixation by the flexor digitorum superficialis muscle, is of fundamental importance in neuropathy syndromes due to entrapment of the MN, as well as in surgical guidance to prevent injuries. Late diagnosis of traumatic peripheral nerve injuries results in greater functional impairment and greater socioeconomic loss, especially in young patients. Therefore, timely identification is essential to minimize long-term consequences and improve the patient's quality of life.

Upper Extremity Nerve Transfers for Treatment of Nerve Injury After Cervical Spine Surgery

Purpose Nerve transfers to restore or augment function after spinal cord injury is an expanding field. There is a paucity of information, however, on the use of nerve transfers for patients having undergone spine surgery. The incidence of neurologic deficit after spine surgery is rare but extremely debilitating. The purpose of this study was to describe the functional benefit after upper extremity nerve transfers in the setting of nerve injury after cervical spine surgery. Methods A single-center retrospective review of all patients who underwent nerve transfers after cervical spine surgery was completed. Patient demographics, injury features, spine surgery procedure, nerve conduction and electromyography study results, time to referral to nerve surgeon, time to surgery, surgical technique and number of nerve transfers performed, complications, postoperative muscle testing, and subjective outcomes were reviewed. Results Fourteen nerve transfers were performed in 6 patients after cervical spine surgery. Nerve transfer procedures consisted of a transfer between a median nerve branch of flexor digitorum superficialis into a biceps nerve branch, an ulnar nerve branch of flexor carpi ulnaris into a brachialis nerve branch, a radial nerve branch of triceps muscle into the axillary nerve, and the anterior interosseous nerve into the ulnar motor nerve. Average patient age was 55 years; all patients were male and underwent surgery on their left upper extremity. Average referral time was 7 months, average time to nerve transfer was 9 months, and average follow-up was 21 months. Average preoperative muscle grading was 0.9 of 5, and average postoperative muscle grading was 4.1 of 5 (P < 0.00001). Conclusions Upper extremity peripheral nerve transfers can significantly help patients regain muscle function from deficits secondary to cervical spine procedures. The morbidity of the nerve transfers is minimal with measurable improvements in muscle function.

New dynamic suture material for tendon transfer surgeries in the upper extremity - a biomechanical comparative analysis.

Early mobilization after tendon surgery is crucial to avoid commonly observed postoperative soft tissue adhesions. Recently, a new suture was introduced (DYNACORD; DC) with a salt-infused silicone core designed to minimize laxity and preserve consistent tissue approximation in order to avoid gap formation and allow early mobilization. To compare the biomechanical competence of DC against a conventional high strength suture (FiberWire; FW) in a human cadaveric tendon transfer model with an early rehabilitation protocol. Sixteen tendon transfers (flexor digitorum superficialis (FDS) IV to flexor pollicis longus (FPL)) were performed in 8 pairs human cadaveric forearms using either DC or FW. Markings were set 0.8cm proximally and 0.7cm distally to the level of the interweaving zone of the transfer. All specimens underwent repetitive thumb flexion against resistance in 9 intermittent series of 300 cycles each, simulating an aggressive postoperative rehabilitation protocol. After each series, the distance of the proximal marker to the interweaving zone (proximal), the length of the interweaving zone (intermediate) and the distance of the distal marker to the interweaving zone (distal) were measured. Pooled data over all nine series, normalized to the immediate postoperative status, demonstrated no significant differences between FW and DC (p ≥ 0.355) for the proximal and distal markers. However, at the intermediate zone, DC was associated with significant length shortening (p < 0.001)compared to FW without significant length changes (p = 0.351). Load to catastrophic failure demonstrated significant higher forces in FW (p = 0.011). Nevertheless, due to failure mainly proximal or distal of the transfer zone, these loads are not informative. From a biomechanical perspective, DC preserved tissue approximation and might be considered as a valid alternative to conventional high-strength sutures in tendon transfer surgery. DC might allow for a shorter interweaving zone and a more aggressive early postoperative rehabilitation program, possibly avoiding commonly observed postoperative soft tissue adhesions and stiffness.

Fractional Lengthening of Forearm Flexor Tendons: A Cadaveric Biomechanical Analysis

Multiple procedures have been described for wrist and finger flexion contractures and spasticity. Fractional lengthening of forearm flexor tendons involves making parallel transverse tenotomies at the musculotendinous junction to elongate the muscle. Currently, there is limited literature to define the biomechanical consequences of this lengthening technique. Forty-eight flexor tendons were harvested from eight paired upper limbs including flexor carpi radialis, flexor carpi ulnaris, flexor pollicis longus, and flexor digitorum superficialis tendons. Each tendon that was lengthened was paired with the contralateral tendon as a control. A pair of transverse tenotomies were completed for the fractional lengthening. The first tenotomy was performed at the musculotendinous junction where the tendon narrowed to 75% of its maximal width. The second tenotomy was made 1 cm distal to the first. Tendon length was measured before and after fractional lengthening at a constant resting tension of 1 N. The maximum load at failure of each tendon and the mechanism of failure were each measured and compared with the contralateral side. After fractional lengthening, the mean increase in resting tendon length was 4 mm. When loaded to failure, the mean maximum load of fractionally lengthened tendons was 42% of the mean maximum load of intact tendons. All lengthened tendons failed at the distal tenotomy site. Fractional lengthening resulted in an increase of 3-6 mm (mean: 4 mm) in tendon length at resting tension. There was a significant loss in tensile strength and load to failure following fractional lengthening compared with an intact musculotendinous unit. The reduction in tensile strength following fractional lengthening results in loads at failure that are, in some cases, lower than the estimated forces required to perform basic tasks. Caution during the healing and rehabilitation period is warranted.

Sensing and Controlling Strategy for Upper Extremity Prosthetics Based on Piezoelectric Micromachined Ultrasound Transducer.

Surface electromyography (sEMG) is currently the primary method for user control of prosthetic manipulation. Its inherent limitations of low signal-to-noise ratio, limited specificity and susceptibility to noise, however, hinder successful implementation. Ultrasound provides a possible alternative, but current systems with medical probes are expense, bulky and non-wearable. This work proposes an innovative prosthetic control strategy based on a piezoelectric micromachined ultrasound transducer (PMUT) hardware system. Two PMUT-based probes were developed, comprising a 23×26 PMUT array and encapsulated in Ecoflex material. These compact and wearable probes represent a significant improvement over traditional ultrasound probes as they weigh only 1.8 grams and eliminate the need for ultrasound gel. A preliminary test of the probes was performed in non-disabled subjects performing 12 different hand gestures. The two probes were placed perpendicular to the flexor digitorum superficialis and brachioradialis muscles, respectively, to transmit/receive pulse-echo signals reflecting muscle activities. Hand gesture was correctly predicted 96% of the time with only these two probes. The adoption of the PMUT-based strategy greatly reduced the required number of channels, amount of processing circuit and subsequent analysis. The probes show promise for making prosthesis control more practical and economical.

A case of a pediatric finger tendon rupture diagnosed by point-of-care ultrasound

BackgroundPediatric tendon injuries to the finger are rare, and their diagnosis can be challenging due to the difficulty in sensorimotor assessment in pediatric patients. Point-of-care ultrasound (POCUS) has currently been used for identifying tendon injury in adult acute care, but reports of its use in pediatric emergency departments are scarce. Case reportA previously healthy 14-year-old male patient visited our emergency department due to a finger laceration that occurred when he was cutting sausages using a knife. Physical examination revealed a 1.5 cm laceration over the palmer surface of the left fifth proximal phalanx. Tendon exposure was unremarkable, and the peripheral perfusion and sensation of the injured finger were intact. Flexion of the proximal and distal interphalangeal joints was limited due to pain. POCUS showed the disruption of the tendon structure over the laceration site, suggesting the flexor tendon rupture. Wound exploration by the orthopedic team revealed a transected flexor digitorum superficialis and flexor digitorum profundus and a tendon repair was performed. The patient was discharged with immobilization of the injured hand. Why should an emergency physician be aware of this?Pediatric tendon injuries to the finger are rare, and their diagnosis can be challenging to diagnose due to the difficulty in sensorimotor assessment in pediatric patients. POCUS can directly visualize a tendon structure without procedural sedation or radiation exposure, empowering physicians to diagnose tendon injuries and optimize patient care.

Treatment for complete extensor tendon rupture: A case report on extensor pollicis longus tendon transfer and tenodesis procedure to radius for a patient with rheumatoid arthritis.

The complete loss of finger extension leads to significant inconvenience in daily life and often requires surgical treatment. Despite some disadvantages, the Boyes method, which uses the flexor digitorum superficialis tendon, is commonly performed for complete extensor rupture. We report the case of a 73-year-old woman living alone diagnosed with a subcutaneous rupture of all extensor tendons from the index to the little finger. The favourable range of motion of her wrist allowed us to perform extensor tenodesis. Additionally, the patient had a dislocated thumb interphalangeal (IP) joint, enabling us to use the extensor pollicis longus (EPL) tendon for tendon transfer in combination with thumb IP joint fusion. The patient demonstrated favourable finger range-of-motion outcomes at the 6-month postoperative assessment. The case shows that EPL tendon transfer and tenodesis may be a viable treatment option for patients with complete extensor rupture accompanied by thumb IP joint deformity and normal wrist range of motion.

A Comparison of Patient Characteristics and Outcomes Between Patients Receiving Flexor Digitorum Superficialis Slip Excision or Isolated A1 Pulley Release for Trigger Finger

Resection of the radial or ulnar slip of the flexor digitorum superficialis (FDS) tendon is a known treatment option for persistent trigger finger. Risk factors for undergoing FDS slip excision are unclear. We hypothesized that patients who underwent A1 pulley release with FDS slip excision secondary to persistent triggering would have a higher comorbidity burden compared to those receiving A1 pulley release alone. We identified all adult patients who underwent A1 pulley release with FDS slip excision because of persistent triggering either intraoperatively or postoperatively from 2018 to 2023. We selected a 3:1 age- and sex-matched control group who underwent isolated A1 pulley release. Charts were retrospectively reviewed for demographics, selected comorbidities, trigger finger history, and postoperative course. We performed multivariable logistic regression to assess the probability of FDS slip excision after adjusting for several variables that were significant in bivariate comparisons. We identified 48 patients who underwent A1 pulley release with FDS slip excision and 144 controls. Our multivariable model showed that patients with additional trigger fingers and a preoperative proximal interphalangeal (PIP) joint contracture were significantly more likely to undergo FDS slip excision. Patients who underwent A1 pulley release with FDS slip excision were significantly more likely to have multiple trigger fingers or a preoperative PIP joint contracture. Clinicians should counsel patients with these risk factors regarding the potential for FDS slip excision in addition to A1 pulley release to alleviate triggering of the affected digit. Therapeutic III.

Contributing factors to hand flexor tendon rerupture

Purpose: This retrospective study aimed to identify factors influencing hand flexor tendon rerupture and to develop preventive strategies for patients who have undergone hand flexor tendon repair.Methods: In total, 287 patients who underwent hand flexor tendon repair between January 2011 and June 2022 were included. Patients with thumb injuries, amputations, bone injuries, extensor tendon injuries, and those with less than 3 months of follow-up were excluded. Patients were divided into rerupture and non-rerupture groups. Events leading to ruptures were also investigated. The two groups were compared according to sex, age, occupation, smoking status, history of diabetes mellitus, injury characteristics, core suture method, and timing of the rehabilitation course.Results: Of the 287 patients, 19 experienced rerupture (6.6%). The mean time to rerupture was 25.3 days. Reruptures occurred due to unknown causes in nine cases (47.4%), noncompliance with medical recommendations in seven cases (36.8%), and trauma in three cases (15.8%). Among the investigated factors, little finger injury and concurrent flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) ruptures were significantly associated with rerupture. Little difference was noted in the core suture methods and timing of the rehabilitation course between the two groups.Conclusion: To minimize the risk of rerupture, patients should strictly adhere to medical recommendations and avoid any activities that could cause trauma for at least 1 month after surgery, which is the critical period for tendon remodeling. Patients with little finger injuries as well as concurrent FDS and FDP ruptures require special attention and careful monitoring.

Infiltration Technique for the Fourth FDS Opponensplasty Under WALANT

Background: Wide-awake Local Anesthesia No Tourniquet (WALANT) is a surgical technique that relies on anesthetic and hemostatic agents to provide conditions suitable for hand surgery without sedation and a tourniquet. The opponensplasty using the fourth flexor digitorum superficialis tendon transfer with the pisiform pulley is one of the most used in severe carpal tunnel syndrome patient who is unable to perform thumb opposition due to thenar muscle atrophy with the benefit of small incision, less soft tissue dissection, easy to perform, good esthetic result and has minor morbidity. Key advantages of the pisiform pulley provide balancing abduction and flexion strength of the thumb. To date, there is no report using the WALANT technique for the fourth flexor digitorum superficialis opponensplasty with pisiform pulley. Materials and Method: Between January 2019 and January 2022, 18 patients (4 males and 14 females) with severe carpal tunnel syndrome with thenar muscle atrophy underwent fourth flexor digitorum superficialis opponensplasty as day surgery under the WALANT technique. Operative data, visual analog scale (VAS) pain scores, and complications were recorded. All patients underwent the procedure without any complications. Results: The average age of the patients was 58.4 (43 to 62) year-old. The average operative time was 38.4 (17 to 47) minutes. The average VAS score during the anesthetic injection was 6.43 (4 to -8). The average VAS pain score during the operation was 2.1 (1 to 3). The mean intraoperative blood loss was 3 (2.6 to 6.2) mL. Conclusions: The WALANT technique is safe and can be used as alternative anesthesia for the fourth flexor digitorum superficialis opponensplasty with pisiform pulley. This technique overcomes the problem of judging the appropriate amount of transfer tension by observing awake patients actively. Levels of Evidence: Therapeutic study, level IV

Patterns in flexor zone V injury: a retrospective study

Background: Volar cut injuries to the wrist that range from simple to complex full house and are commonly encountered by plastic surgery residents. In this study we aim to recognize common clusters of structures injured together, to decipher patterns in presentation and to assert the role of superficial tendons in protecting the nerves, vessels and the deeper tendons in the flexor compartment. Methods: This is a retrospective cross-sectional study analyzing 322 patients with acute Zone V injuries. The patients were profiled based on demographic factors and etiology of injury. Detailed analysis of morphology of injury, structures involved was done and grouped into six common injury patterns. Results: Majority of subjects were in the age group 21 to 30 years (33.9%), 81.1% were males and 18.9% were females. Both the sides flexor carpi radialis, Palmaris longus and flexor digitorum superficialis were commonly injured structures. Most common etiology was cutting tools. The median number of structures injured in cutting injuries was 3, in deliberate self-harm was 3, in Power tool was 6, in Shard injuries was 5 structures. Distribution of injuries was pattern 1 (98.2%), pattern 2 (36.2%), pattern 3 (40.5%), pattern 4 (80.1%), pattern 5 (15.6%) and pattern 6 (21.5%). Pattern 1 was seen commonly in all etiologies whereas power tools were responsible for serious pattern 6 types of injuries. Conclusions: Cut injury to wrist occurs as clusters of specific structures and these patterns need to be looked for during surgical repair of hand. Superficial tendons have a role in protecting deeper tendons and neurovascular structures.

Efficacy of Minimally Invasive Ulnar Superficialis Slip Resection for Unfavourable Results after Trigger Finger Release.

Background: This study aimed to evaluate the efficacy of ulnar superficial slip resection (USSR) for improving hand function after unfavourable results after triggering finger release using a minimally invasive approach. Methods: We evaluated 17 consecutive fingers of 16 patients who complained of unfavourable outcomes after primary trigger finger release. The chief complaints of the two index and 15 middle fingers were proximal interphalangeal (PIP) joint pain during movement, flexion contracture of the PIP joint and snapping at the A2 pulley in eight, seven and two fingers, respectively. The joint arc of the active range of motion and extension loss of the PIP joint, grip strength, visual analogue score (VAS) of PIP joint pain and Quick Disability of the Arm, Shoulder and Hand were evaluated before and after surgery. Results: Thirteen fingers could release joint contracture and snapping by the USSR procedure. However, four fingers of three patients required total flexor digitorum superficialis resection to resolve the unsatisfactory conditions of the intraoperative decision. The joint arc of active range of motion and extension loss of the PIP joint, grip strength and VAS score significantly improved (mean of 16.1 months follow-up). Finally, 15 patients (88.2%) were satisfied with the symptom relief outcomes. Conclusions: USSR is an effective and satisfactory procedure for unfavourable conditions after trigger finger release, including PIP joint pain, joint contracture and snapping at the A2 pulley. Level of Evidence: Level IV (Therapeutic).

Elasticity assessment of flexor pronator muscles using shear wave elastography

BackgroundThe flexor pronator muscles (FPMs) have been thought as a dynamic stabilizer to protect the ulnar collateral ligament (UCL) from valgus stress during throwing motion. Thus, evaluation of the FPMs is important for preventing UCL injuries. Shear wave ultrasound elastography (SWE) is an imaging modality that quantifies tissue elasticity. The purpose of this study was to measure the tissue elasticities of healthy FPMs using SWE. MethodsWe investigated 22 healthy men (mean age, 29 ± 6 years). The elasticities of the FPMs, including the pronator teres (PT), flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU), were measured using SWE for each arm under two conditions: at rest (unloaded) and under valgus stress (loaded). The values obtained under different loading conditions were compared between both elbows. ResultsThe mean SWE values of the PT, FDS, and FCU for the dominant elbows were 22.4 ± 3.6, 22.8 ± 2.9, and 22.3 ± 3.4 kPa, respectively. The corresponding mean SWE values for the non-dominant elbows were 24.2 ± 4.6, 23.1 ± 3.5, and 23.4 ± 3.5 kPa, respectively. The mean SWE values of the PT, FDS, and FCU at rest (unloaded) were 23.3 ± 4.2, 22.9 ± 3.2, and 22.9 ± 3.5 kPa, respectively. The corresponding mean SWE values under valgus stress (loaded) were 35.0 ± 6.2, 34.7 ± 5.3, 31.9 ± 4.8 kPa, respectively. ConclusionThis non-invasive evaluation of the stiffness of the FPMs may provide clinically relevant data for the prevention of UCL injuries.

Functional Outcome of Primary Repair of Long Flexors of Finger at Zone V with Early Mobilization

A prospective, observational study was conducted in National Institute of Traumatology and Orthopaedic Rehabilitation (NITOR), Dhaka, Bangladesh, between September 2019 and March 2021, to observe the functional outcome of primary repair of long flexors of finger at zone V with early mobilization. Our study included 51 patients, who had follow-up visits up to 12 months after operation. Tendon functionality was assessed by Buck-Gramcko score, while grip strength was assessed by modified sphygmomanometer. The mean age was 30.08±13.38 years. Middle and index fingers were most involved with both flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) injury. In this study, most of the patients had excellent or good outcomes. The average return to work time was 32.82 weeks. 9.8% of the patients developed post-operative complications like infections, adhesion, and rupture. Most of the patients obtained good to excellent results (90%), while 3.92% had fair and only 2% had poor outcome. Early motion of the fingers seems to improve outcome in these patients. However, worse outcomes were seen in patients with a greater number of damaged structures, especially in concomitant nerve injury. CBMJ 2024 January: vol. 13 no. 01 P: 83-88

Towards hand grip force assessment by using EMG estimators

The purpose of this study was to propose a method to assess individual regression (calibration) curves to establish a relationship between an isometric grip force and surface electromyography (EMG) estimator. In this study 18 healthy volunteers (12 male (23.0 ± 2.0 years) and 6 female (23.2 ± 0.7 years)) had been examined. Ten EMG estimators (mean absolute value, root mean square, entropy, energy, turns per second, mean of zero crossings, median power frequency, mean power frequency, and Hilbert transforms), two EMG locations (brachioradialis and flexor digitorum superficialis) and five types of regression curves (linear, exponential, power, logarithm, and quadratic polynomial) have been tested. Using a quadratic polynomial regression curve and energy EMG estimator of the flexor digitorum superficialis muscle, it was obtained the lowest dispersity of EMG estimator and the most accurate prediction of grip isometric force among all tested EMG estimators.

Cadaveric study of flexor digitorum profundus and superficialis and flexor pollicis longus innervation patterns for application in selective neurectomy

PurposeSpasticity management in finger flexors (flexor digitorum profundus and superficialis and flexor pollicis longus) is a challenge.Recent studies demonstrated the short- and long-term efficacy of selective and hyperselective neurectomy for the spastic upper limb. However, hyperselective neurectomy of flexor digitorum profundus and flexor digitorum superficialis branches was incomplete, without impairing their muscular body and function.This cadaveric study describes a novel medial approach in the forearm, to reach all the muscular branches: flexor digitorum superficialis and profundus and flexor pollicis longus. Material and methodsFourteen cadaveric fresh frozen upper limbs were used. The feasibility of the medial surgical approach was studied, as well as the number, length and point of emergence of the muscular branches from the median and ulnar nerves to the flexor pollicis longus, flexor digitorum profundus and flexor digitorum superficialis. ResultsThe medial approach to the forearm gave access to all the muscular branches from the median and ulnar nerves to the flexor pollicis longus, flexor digitorum superficialis and flexor digitorum profundus, in all cases. A Martin Gruber communicating branch was found in 7 cases out of 14. ConclusionThe medial approach to the forearm gave access to all the muscular branches from the median and ulnar nerve to the flexor pollicis longus, flexor digitorum superficialis and flexor digitorum profundus, without extensive transmuscular dissection of the pronator teres or flexor digitorum superficialis muscles. This approach opens the way for selective neurectomy of the flexor pollicis longus, flexor digitorum profundus and flexor digitorum superficialis muscles. Level of evidenceIV.

Flexor Pronator Slide Under Local Anesthesia without a Tourniquet for Non-Ischemic Contractures of the Forearm.

Flexor Pronator Slide Under Local Anesthesia without a Tourniquet for Non-Ischemic Contractures of the Forearm.

Analysis of Multiscale Corticomuscular Coupling Networks Based on Ordinal Patterns.

The coupled analysis of corticomuscular function based on physiological electrical signals can identify differences in causal relationships between electroencephalogram (EEG) and surface electromyogram (sEMG) in different motor states. The existing methods are mainly devoted to the analysis in the same frequency band, while ignoring the cross-band coupling, which plays an active role in motion control. Considering the inherent multiscale characteristics of physiological signals, a method combining Ordinal Partition Transition Networks (OPTNs) and Multivariate Variational Modal Decomposition (MVMD) was proposed in this paper. The EEG and sEMG were firstly decomposed on a time-frequency scale using MVMD, and then the coupling strength was calculated by the OPTNs to construct a corticomuscular coupling network, which was analyzed with complex network parameters. Experimental data were obtained from a self-acquired dataset consisting of EEG and sEMG of 16 healthy subjects at different sizes of constant grip force. The results showed that the method was superior in representing changes in the causal link among multichannel signals characterized by different frequency bands and grip strength patterns. Complex information transfer between the cerebral cortex and the corresponding muscle groups during constant grip force output from the human upper limb. Furthermore, the sEMG of the flexor digitorum superficialis (FDS) in the low frequency band is the hub in the effective information transmission between the cortex and the muscle, while the importance of each frequency component in this transmission network becomes more dispersed as the grip strength grows, and the increase in coupling strength and node status is mainly in the γ band (30~60Hz). This study provides new ideas for deconstructing the mechanisms of neural control of muscle movements.

Staged Tendon Repair to Improve Range of Motion in Tamai Zone 4 Replantation: Two Case Reports.

Tamai zone 4 replantation, defined as the replantation at a level proximal to the flexor digitorum superficialis' insertion and distal to where the common digital artery branches into the proper digital artery, has poor functional results because making orthosis and rehabilitation protocols that protect the bone and the flexor and extensor tendons simultaneously difficult. Two cases of Tamai zone 4 replantation are presented: one case of an index finger replantation at the proximal phalanx and a case of ring finger replantation at the proximal interphalangeal joint. The author did not repair the flexor tendon intentionally in the primary replantation and performed two-stage flexor tendon reconstruction later. The total active motions (TAMs) at the last follow-up were 215 and 180 degrees, respectively, with the latter distal interphalangeal joint being an arthrodesis. Both cases had no extension lag in the proximal interphalangeal joint. These results were much better than those in previous reports, in which the mean TAM was 133 degrees or less. The good results appeared to be mainly due to the reasonable and clear postoperative rehabilitation protocols made by the proposed procedure. This procedure may be useful for obtaining reproducible functional results even in Tamai zone 4 replantation.