Varus knee osteoarthritis with ankle osteoarthritis demonstrates greater hindfoot inversion and larger ankle inversion loading during gait following total knee arthroplasty compared to varus knee osteoarthritis alone.

PURPOSE: Although patients with varus knee osteoarthritis (KOA) and concurrent ankle osteoarthritis (AOA) may experience increased ankle joint pain after total knee arthroplasty (TKA), the underlying mechanism remains unclear. This study aimed to investigate the effects of concurrent AOA on ankle and hindfoot alignment, frontal plane ankle and hindfoot biomechanics during gait following TKA and the clinical outcomes. METHODS: Twenty-four patients with varus KOA who underwent TKA were included in this retrospective cohort study. Patients were categorized into two groups: with and without AOA. Radiographic evaluations of lower-limb, ankle and hindfoot alignment, and knee and ankle clinical outcomes were conducted preoperatively and 6 months postoperatively. In addition, gait analyses were performed to investigate knee, ankle and hindfoot kinematics and kinetics. Each data was compared between patients with and without AOA. RESULTS: Concomitant AOA was found in eight ankles. The AOA group exhibited greater postoperative hindfoot varus and increased postoperative ankle pain than the non-AOA group. Gait analysis showed no significant differences in knee varus alignment or tibial tilt after TKA between the groups. However, the AOA group demonstrated significantly greater hindfoot inversion and larger ankle inversion loading. CONCLUSION: One third of patients who underwent TKA had concurrent AOA associated with hindfoot varus. Despite achieving proper coronal knee alignment postoperatively, these patients experienced greater hindfoot and ankle joint inversion load during gait. Surgeons should consider the inability to evert the hindfoot and the possibility of increased ankle joint pain when planning and performing TKA. LEVEL OF EVIDENCE: Level III.

Feasibility and Efficacy of the Newly Developed Robotic Hybrid Assistive Limb Shoulder Exercises in Patients with C5 Palsy during the Acute Postoperative Phase.

Background and Objectives: Although postoperative C5 palsy is a frequent complication of cervical spine surgery, no effective therapeutic rehabilitation approach has been established for postoperative C5 palsy. The purpose of this study was to find evidence confirming the effectiveness and feasibility of robotic Hybrid Assistive Limb (HAL) shoulder exercises for C5 palsy. Materials and Methods: In this before-after, uncontrolled case series clinical study, we performed a mean of 11.7 shoulder training sessions using a shoulder HAL immediately after the onset of C5 palsy in seven shoulders of six patients who developed postoperative C5 palsy and had difficulty raising their shoulder during the acute postoperative phase of cervical spine surgery. Shoulder HAL training was introduced as early as possible after evaluating the general condition of all inpatients who developed C5 palsy. Patients underwent shoulder abduction training using shoulder HAL on an inpatient and outpatient basis at 2-week or 1-month intervals. Adverse events associated with shoulder HAL training were investigated. The shoulder abduction angle and power without the shoulder HAL were evaluated before shoulder HAL usage, at every subsequent session, and upon completion of all sessions. Results: Severe adverse events due to shoulder HAL training were not reported. After completion of all shoulder HAL sessions, all patients showed improved shoulder elevation, while shoulder abduction angle and power improved over time. Conclusions: Shoulder elevation training with HAL in patients in the acute stage of postoperative C5 palsy has the potential to demonstrate improvement in shoulder joint function with a low risk of developing severe adverse events.

The relationship between spinal alignment and activity of paravertebral muscle during gait in patients with adult spinal deformity: a retrospective study.

BACKGROUND: Spinal alignment in patients with adult spinal deformity (ASD) changes between rest and during gait. However, it remains unclear at which point the compensated walking posture breaks down and how muscles respond. This study used time-synchronized electromyography (EMG) to investigate the relationship between dynamic spinal alignment and muscle activity during maximum walking duration to reveal compensation mechanisms. METHODS: This study collected preoperative three-dimensional gait analysis data from patients who were candidates for corrective surgery for ASD from April 2015 to May 2019. We preoperatively obtained dynamic spinal alignment parameters from initiation to cessation of gait using a motion capture system with time-synchronized surface integrated EMG (iEMG). We compared chronological changes in dynamic spinal alignment parameters and iEMG values 1) immediately after gait initiation (first trial), 2) half of the distance walked (half trial), and 3) immediately before cessation (last trial). RESULTS: This study included 26 patients (22 women, four men) with ASD. Spinal sagittal vertical axis distance during gait (SpSVA) increased over time (first vs. half vs. last, 172.4 ± 74.8 mm vs. 179.9 ± 76.8 mm vs. 201.6 ± 83.1 mm; P < 0.001). Cervical paravertebral muscle (PVM) and gluteus maximus activity significantly increased (P < 0.01), but thoracic and lumbar PVM activity did not change. Dynamic spinal alignment showed significant correlation with all muscle activity (cervical PVM, r = 0.41-0.54; thoracic PVM, r = 0.49-0.66; gluteus maximus, r = 0.54-0.69; quadriceps, r = 0.46-0.55) except lumbar PVM activity. CONCLUSION: Spinal balance exacerbation occurred continuously in patients with ASD over maximum walking distance and not at specific points. To maintain horizontal gaze, cervical PVM and gluteus maximus were activated to compensate for a dynamic spinal alignment change. All muscle activities, except lumbar PVM, increased to compensate for the spinal malalignment over time.

Postoperative Acute-Phase Gait Training Using Hybrid Assistive Limb Improves Gait Ataxia in a Patient with Intradural Spinal Cord Compression Due to Spinal Tumors.

Sensory ataxia due to posterior cord syndrome is a relevant, disabling condition in nontraumatic spinal cord dysfunction. Ataxic gait is a common symptom of sensory ataxia that restricts activities of daily living. A 70-year-old woman with severe sensory disturbance was diagnosed with intradural extramedullary spinal cord tumors found in the thoracic spine region (T8). Surgical management of the tumors was performed. The patient received gait training 20 days after surgery (postoperative acute phase) using a hybrid assistive limb (HAL). HAL is a wearable exoskeleton cyborg that provides real-time assistance to an individual for walking and limb movements through actuators mounted on the bilateral hip and knee joints. Walking ability was assessed using the 10 m walking test, which included evaluating walking speed, step length, and cadence in every session. To evaluate the immediate effects of HAL training, walking speed and step length were measured before and after the training in each session. During the 10 m walking test, gait kinematics and lower muscle activity were recorded using a motion capture system and wireless surface electromyography before the first session and after completion of all HAL sessions. After the HAL training sessions, improvement in the patient's gait performance was observed in the gait joint angles and muscle activity of the lower limb. After 10 training sessions, we observed the following changes from baseline: walking speed (from 0.16 m/s to 0.3 m/s), step length (from 0.19 m to 0.37 m), and cadence (from 50.9 steps/min to 49.1 steps/min). The average standard deviations of the knee (from right, 7.31; left, 6.75; to right, 2.93; p < 0.01, left, 2.63; p < 0.01) and ankle joints (from right, 6.98; left, 5.40; to right, 2.39; p < 0.01, left, 2.18; p < 0.01) were significantly decreased. Additionally, walking speed and step length improved immediately after completing all the HAL training sessions. This suggests that HAL gait training might be a suitable physical rehabilitation program for patients with sensory ataxia causing dysfunctional movement of the lower limb.

Can Proximal Junctional Kyphosis after Surgery for Adult Spinal Deformity Be Predicted by Preoperative Dynamic Sagittal Alignment Change with 3D Gait Analysis? A Case-Control Study.

BACKGROUND: Severe spinal deformity is a risk factor for proximal junctional kyphosis (PJK) in surgery for adult spinal deformity (ASD). However, standing X-ray imaging in patients with dynamic spinal imbalance can underestimate the risk of PJK because of compensation mechanisms. This study aimed to investigate whether preoperative dynamic spinal alignment can be a predictive factor for PJK. METHODS: We retrospectively included 27 ASD patients undergoing three-dimensional (3D) gait analysis before surgery. Dynamic spinal parameters were obtained using a Nexus motion capture system (Vicon, Oxford, UK). The patients were instructed to walk as long as possible around an oval walkway. The averaged dynamic parameters in the final lap were compared between patients with PJK (+) and with PJK (-). RESULTS: PJK occurred in seven patients (26%). The dynamic angle between the thoracic spine and pelvis was larger in patients with PJK (+) than in those with PJK (-) (32.3 ± 8.1 vs. 18.7 ± 13.5 °, p = 0.020). Multiple logistic regression analysis identified this angle as an independent risk factor for PJK. CONCLUSIONS: Preoperative thoracic anterior inclination exacerbated by gait can be one of preoperative independent risk factors for PJK in patients undergoing corrective surgery for ASD.

Development of a New Ankle Joint Hybrid Assistive Limb.

Foot and ankle disabilities (foot drop) due to common peroneal nerve palsy and stroke negatively affect patients' ambulation and activities of daily living. We developed a novel robotics ankle hybrid assistive limb (HAL) for patients with foot drop due to common peroneal nerve palsy or stroke. The ankle HAL is a wearable exoskeleton-type robot that is used to train plantar and dorsiflexion and for voluntary assistive training of the ankle joint of patients with palsy using an actuator, which is placed on the lateral side of the ankle joint and detects bioelectrical signals from the tibialis anterior (TA) and gastrocnemius muscles. Voluntary ankle dorsiflexion training using the new ankle HAL was implemented in a patient with foot drop due to peroneal nerve palsy after lumbar surgery. The time required for ankle HAL training (from wearing to the end of training) was approximately 30 min per session. The muscle activities of the TA on the right were lower than those on the left before and after ankle HAL training. The electromyographic wave of muscle activities of the TA on the right was slightly clearer than that before ankle HAL training in the resting position immediately after ankle dorsiflexion. Voluntary ankle dorsiflexion training using the novel robotics ankle HAL was safe and had no adverse effect in a patient with foot drop due to peroneal nerve palsy.

Immediate effects of hybrid assistive limb gait training on lower limb function in a chronic myelopathy patient with postoperative late neurological deterioration.

OBJECTIVE: The Hybrid Assistive Limb (HAL) has recently been used to treat movement disorders. Although studies have shown its effectiveness for chronic myelopathy, the immediate effects of HAL gait training on lower limb function have not been clarified. We conducted HAL gait training and examined its immediate effects on a 69-year-old man with re-deterioration of myelopathy in the chronic phase after surgery for compression myelopathy. The HAL intervention was performed every 4 weeks for 10 total sessions. Immediately before and after each session, we analyzed the patient's walking ability using the 10-m walk test. In the 4th HAL session, the gastrocnemius muscle activity was measured bilaterally using a synchronized motion capture-electromyogram system. RESULTS: The training effects became steady after the 2nd session. In sessions 2-10, the step length increased from 0.56 to 0.63 m (mean: 0.031 m) immediately after HAL training. The motion capture-electromyogram analyses showed that considerable amounts of gastrocnemius muscle activity were detected during the stance and swing phases before HAL training. During and immediately after HAL training, gastrocnemius activity during the swing phase was diminished. HAL gait training has an immediate effect for inducing a normal gait pattern with less spasticity in those with chronic myelopathy.

Robotic Shoulder Rehabilitation With the Hybrid Assistive Limb in a Patient With Delayed Recovery After Postoperative C5 Palsy: A Case Report.

C5 palsy is a serious complication that may occur after cervical spine surgery; however, standard procedures for shoulder rehabilitation for patients with postoperative C5 palsy have not yet been established. We used a wearable robot suit Hybrid Assistive Limb (HAL) in a patient with delayed recovery after postoperative C5 palsy and conducted shoulder abduction training with the HAL. A 62-year-old man presented with weakness in his left deltoid muscle 2 days after cervical spine surgery. He experienced great difficulty in elevating his left arm and was diagnosed with postoperative C5 palsy. Seven months after surgery, shoulder abduction training with a HAL was initiated. In total, 23 sessions of shoulder HAL rehabilitation were conducted until 26 months after surgery. His shoulder abduction angle and power improved at every HAL session, and he was able to fully elevate his arm without any compensatory movement after the 23rd session, suggesting that the HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy. We employed shoulder HAL training for a patient with delayed recovery from postoperative C5 palsy and achieved complete restoration of shoulder function. We believe that the HAL-based training corrected the erroneous motion pattern of his paralyzed shoulder and promoted errorless motor learning for recovery. Our collective experience suggests that shoulder HAL training could be an effective therapeutic tool for patients with postoperative C5 palsy.

Adjustment effect during shoulder abduction training with the Hybrid Assistive Limb in a patient with postoperative C5 palsy.

Standard shoulder rehabilitation procedures for patients with postoperative C5 palsy have not yet been established. We applied a wearable robot suit hybrid assistive limb (HAL) for a patient with postoperative C5 palsy and conducted shoulder abduction training with HAL. A 65-year-old woman was diagnosed with postoperative C5 palsy after undergoing cervical spine surgery. Five days after surgery, shoulder abduction training with HAL was initiated. The shoulder abduction angle and power and trapezius and deltoid activities were evaluated. Ten rehabilitation sessions were conducted until 82 days after surgery. Shoulder abduction training was safely and effectively performed from the first session. Her shoulder abduction angle and power improved at every session, and she could fully elevate her arm without any compensatory motion after the 10th session. Shoulder HAL training suppressed the muscular activity of the trapezius and activated that of the deltoid, especially in the earlier stages of rehabilitation. Moreover, it had an adjustment effect for obtaining normal shoulder motion, which might have promoted smoother arm elevation using errorless motor learning. These findings suggest that HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy.

Analysis of Gait Motion Changes by Intervention Using Robot Suit Hybrid Assistive Limb (HAL) in Myelopathy Patients After Decompression Surgery for Ossification of Posterior Longitudinal Ligament.

Ossification of the posterior longitudinal ligament (OPLL) is a hyperostonic condition in which the posterior longitudinal ligament becomes thick and loses its flexibility, resulting in ectopic ossification and severe neurologic deficit (Matsunaga and Sakou, 2012). It commonly presents with myelopathy and radiculopathy and with myelopathy progression motor disorders and balance disorders can appear. Even after appropriate surgical decompression, some motor impairments often remain. The Hybrid Assistive Limb (HAL) is a wearable powered suit designed to assist and support the user's voluntary control of hip and knee joint motion by detecting bioelectric signals from the skin surface and force/pressure sensors in the shoes during movement. In the current study, the HAL intervention was applied to 15 patients diagnosed with OPLL who presented with myelopathy after decompression surgery (6 acute and 9 chronic stage). Following the HAL intervention, there were significant improvements in gait speed, cadence, stride length, in both acute and chronic groups. Joint angle analysis of the lower limbs showed that range of motion (ROM) of hip and knee joints in acute group, and also ROM of hip joint and toe-lift during swing in chronic group increased significantly. ROM of knee joint became closer to healthy gait in both groups. Electromyography analysis showed that hamstrings activity in the late swing phase increased significantly for acute patients. Immidiate effect from HAL session was also observed. EMG of vastus medialis were decreased except chronic 7th session and EMG of gastrocnemius were decreased except acute 7th session, which suggests the patients were learning to walk with lesser knee-hypertension during the sessions. After all, double knee action appeared in both acute and chronic groups after the HAL intervention, rather than knee hyper-extension which is a common gait impairment in OPLL. We consider that these improvements lead to a smoother and healthier gait motion.

Hybrid assistive limb (HAL) treatment for patients with severe thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL) in the postoperative acute/subacute phase: A clinical trial.

Context/Objective: The hybrid assistive limb (HAL) is a wearable exoskeleton robot that assists walking and lower limb movements via real-time actuator control. Our aim was to clarify the safety and feasibility of using the HAL robotic suit for rehabilitation in patients with severe thoracic myelopathy due to ossification of the posterior longitudinal ligament (T-OPLL). Design: Uncontrolled case series; pre- and post-intervention measurement. Setting: In-patient rehabilitation unit. Intervention: HAL training was provided in 60-minuts session, 2-3 sessions per week, for a total of 10 sessions. HAL training was initiated on average 27.5 days post-surgery. Patients: Eight patients (four males and four females; mean age, 60.9 ± 10.2 years) with severe myelopathy, who had undergone posterior decompression with instrumented fusion, were enrolled. Outcome Measures: Gait speed, step length and cadence were measured along a 10-m walkway every session. The American Spinal Injury Association (ASIA) motor score (lower extremities) and Walking Index for Spinal Cord Injury (WISCI) II were also evaluated at baseline and after 10 sessions. The Japanese Orthopaedic Association (JOA) score was calculated over time after surgery. Results: All participants completed the 10 training sessions, with no serious adverse effect noted. Gait speed, step length and cadence improved over time. Both the WISCI-II and ASIA motor (lower extremities) scores improved from baseline after 10 sessions. The JOA score improved over time post-surgery. Conclusion: HAL training can be feasibly initiated in the early postoperative period, without severe adverse events in patients, with T-OPLL-related severe gait disturbance.

Walking ability following hybrid assistive limb treatment for a patient with chronic myelopathy after surgery for cervical ossification of the posterior longitudinal ligament.

CONTEXT: The hybrid assistive limb (HAL) (the wearable robot) can assist kinesis during voluntary control of hip and knee joint motion by detecting the wearer's bioelectric signals on the surface of their skin. The purpose of this study was to report on walking ability following the wearable robot treatment in a patient with chronic myelopathy after surgery for cervical ossification of the posterior longitudinal ligament (OPLL). FINDINGS: The patient was a 66-year-old woman with cervical OPLL who was able to ambulate independently with the aid of bilateral crutches. The wearable robot treatment was received once every 2 weeks for ten sessions beginning approximately 14 years after surgery. Improvements were observed in gait speed (BL 22.5; post 46.7 m/min), step length (BL 0.36; post 0.57 m), and cadence (BL 61.9; post 81.6 m/min) based on a 10-m walk test and a 2-minute walk test (BL 63.4; post 103.7 m) assessing total walking distance. The improvements in walking ability were maintained after the wearable robot treatment for 6 months. CONCLUSION: We report the functional recovery in the walking ability of a patient with chronic cervical myelopathy following the wearable robot treatment, suggesting that as a rehabilitation tool, the wearable robot has the potential to effectively improve functional ambulation in chronic cervical myelopathy patients whose walking ability has plateaued, even many years after surgery.

Visualization of walking speed variation-induced synchronized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles with a newly developed gait analysis system.

PURPOSE: To evaluate a newly developed system for dynamic analysis of gait kinematics and muscle activity. METHODS: We recruited 10 healthy men into this study. Analyses of three-dimensional motion and wireless surface electromyogram (EMG) were integrated to achieve synchronous measurement. The participants walked continuously for 10 min under two conditions: comfortable and quick pace. Outcome measures were joint angles of the lower limbs determined from reflective markers and myoelectric activity of trunk and lower limbs determined from EMG sensors, comparing comfortable and quick gait pace. RESULTS: Lower limb joint angle was significantly greater at the quick pace (maximum flexion of the hip joint: 4.1°, maximum extension of hip joint: 2.3°, and maximum flexion of the knee joint while standing: 7.4°). The period of maximum flexion of the ankle joint during a walking cycle was 2.5% longer at a quick pace. EMG amplitudes of all trunk muscles significantly increased during the period of support by two legs (cervical paraspinal: 55.1%, latissimus dorsi: 31.3%, and erector spinae: 32.6%). EMG amplitudes of quadriceps, femoral biceps, and tibialis anterior increased significantly by 223%, 60.9%, and 67.4%, respectively, between the periods of heel contact and loading response. EMG amplitude of the gastrocnemius significantly increased by 102% during the heel-off period. CONCLUSION: Our gait analysis synchronizing three-dimensional motion and wireless surface EMG successfully visualized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles induced by various walking speeds.

Robotic rehabilitation training with a newly developed upper limb single-joint Hybrid Assistive Limb (HAL-SJ) for elbow flexor reconstruction after brachial plexus injury: A report of two cases.

This study aimed to evaluate the effectiveness and safety of using the upper limb single-joint Hybrid Assistive Limb (upper limb HAL-SJ) during elbow flexion training following elbow flexor reconstruction for brachial plexus injury (BPI). We present the cases of two patients in whom the upper limb HAL-SJ was implemented 5 and 7 months postoperatively following elbow flexor reconstruction for BPI. They underwent elbow flexor reconstruction with intercostal nerve crossing-to-musculocutaneous nerve (ICN-MCN crossing) after BPI. Postoperative training using the upper limb HAL-SJ was started from the Medical Research Council (MRC) grade 1 elbow flexion power to MRC grade 3 once every week or every 2 weeks. Both patients could implement elbow training using the upper limb HAL-SJ even in MRC grade 1 of their elbow flexion power. Training with the upper limb HAL-SJ was performed safely and effectively in two patients with elbow flexor reconstruction with ICN crossing after BPI.

Successful detection of postoperative improvement of dynamic sagittal balance with a newly developed three-dimensional gait motion analysis system in a patient with iatrogenic flatback syndrome: A case report.

A 75-year-old Japanese woman with Parkinson's disease complained of lower back pain and gait disturbance because of iatrogenic flatback syndrome. The preoperative global spinal parameters were as follows: C7SVA, 168 mm; TK, 52°; LL, -0.8°; PI, 57°; PT, 55°; TPA, 60°. We performed 3D gait analysis using a VICON System and calculated the dynamic SVA. Preoperatively, her flexion deformity gradually progressed during walking. The dynamic parameters gradually increased as follows: thoracic SVA, 216-241 mm; lumbar SVA, 53-69 mm; spinal SVA, 270-311 mm. We performed two-stage corrective surgery. Her lower back pain and gait disturbance significantly improved. The postoperative global spinal parameters were as follows: C7SVA, 1 mm; TK, 47°; LL, 61°; PI, 52°; PT, 20°; TPA, 13°. Dynamic SVA detected by our 3D gait analysis using VICON were as follows: thoracic SVA, 128 mm; lumbar SVA, 4.9 mm; and spinal SVA, 133 mm. The postoperative dynamic SVA did not change during walking. This is the first report of a patient with iatrogenic flatback syndrome whose postoperative improvement of dynamic spinal sagittal alignment was successfully detected with a newly developed 3D gait analysis system that enabled us to analyze a dynamic change of SVA based on the patient's actual walking with a continuous long-distance gait. Our 3D gait analysis has potential usefulness for evaluating postoperative sagittal balance for iatrogenic flatback syndrome.

Reshaping of Gait Coordination by Robotic Intervention in Myelopathy Patients After Surgery.

The Ossification of the Posterior Longitudinal Ligament (OPLL) is an idiopathic degenerative spinal disease which may cause motor deficit. For patients presenting myelopathy or severe stenosis, surgical decompression is the treatment of choice; however, despite adequate decompression residual motor impairment is found in some cases. After surgery, there is no therapeutic approach available for this population. The Hybrid Assistive Limb® (HAL) robot suit is a unique powered exoskeleton designed to predict, support, and enhance the lower extremities performance of patients using their own bioelectric signals. This approach has been used for spinal cord injury and stroke patients where the walking performance improved. However, there is no available data about gait kinematics evaluation after HAL therapy. Here we analyze the effect of HAL therapy in OPLL patients in acute and chronic stages after decompression surgery. We found that HAL therapy improved the walking performance for both groups. Interestingly, kinematics evaluation by the analysis of the elevation angles of the thigh, shank, and foot by using a principal component analysis showed that planar covariation, plane orientation, and movement range evaluation improved for acute patients suggesting an improvement in gait coordination. Being the first study performing kinematics analysis after HAL therapy, our results suggest that HAL improved the gait coordination of acute patients by supporting the relearning process and therefore reshaping their gait pattern.

Hybrid Assistive Limb Intervention in a Patient with Late Neurological Deterioration after Thoracic Myelopathy Surgery due to Ossification of the Ligamentum Flavum.

PURPOSE: We evaluated improvements in gait after using the Hybrid Assistive Limb (HAL®) exoskeleton robot in a patient with late-onset neurological deterioration of lower extremity function after undergoing thoracic spine surgery for a myelopathy due to ossification of the ligamentum flavum. CASE PRESENTATION: A 70-year-old man participated in ten 20 min sessions of HAL intervention, twice weekly for five weeks. The effects of each HAL session were evaluated based on changes in performance on the 10 m walk test (10 MWT), lower limb kinematics quantified from motion capture, and the activation ratio of the gastrocnemius, measured before and after the intervention. Muscle activity was recorded using surface electromyography and synchronized to measured kinematics. The HAL intervention improved gait speed and step length, with an increase in the hip flexion angle during the swing phase and a decrease in the activation ratio of the gastrocnemius. The modified Ashworth scale improved from 1+ to 1 and International Standards for Neurological and Functional Classification of Spinal Cord Injury motor scores from 34 to 49. CONCLUSION: Intervention using the HAL exoskeleton robot may be an effective method to improve functional ambulation in patients with chronic spinal disorders.

Application of a newly developed upper limb single-joint hybrid assistive limb for postoperative C5 paralysis: An initial case report indicating its safety and feasibility.

Postoperative C5 paralysis is a serious complication of cervical spine surgery, with no established method for effective rehabilitation. A 67-year-old man presented with postoperative bilateral C5 paralysis following cervicothoracic surgery for ossification of the posterior longitudinal ligament (OPLL). Starting 15 days after surgery, left elbow joint training was performed 2-3 times weekly, for a total of 10 sessions, using an upper limb single-joint hybrid assistive limb (upper limb HAL-SJ). Right elbow joint training was also performed 5 times weekly starting 38 days after surgery, for a total of 10 sessions, using the upper limb HAL-SJ. No serious adverse events were noted during treatment with the upper limb HAL-SJ. Manual muscle testing showed no apparent change in deltoid and biceps strength on either side during use of the upper limb HAL-SJ; however, hand-held dynamometer testing showed improvement over time in both muscles. At 12 months after surgery, the patient was able to elevate both arms. The present case indicates initial safety and feasibility of treatment for postoperative C5 paralysis with an upper limb HAL-SJ.

Shoulder motion assistance using a single-joint Hybrid Assistive Limb® robot: Evaluation of its safety and validity in healthy adults.

PURPOSES: To evaluate the feasibility of using the single-joint Hybrid Assistive Limb® robot (HAL) to assist with shoulder flexion-extension in healthy adults, and to assess the capacity of the HAL to analyze the bioelectrical signals of muscle activity for shoulder flexion-extension. METHODS: This cross-sectional feasibility study included six healthy adult men with no impairment in shoulder motion. The single-joint HAL was fixed to a custom-designed platform and upper arm attachment, and aligned 3 cm below the acromion process. Vital signs, shoulder fatigue, and shoulder pain were evaluated before and after the shoulder elevation exercise performed with and without the HAL. Activity of selected muscles of the shoulder was recorded using a wireless superficial electromyography device. Shoulder movement was captured using a three-dimensional motion analysis system. RESULTS: The HAL supported smooth flexion-extension of the arm at the shoulder joint, with no negative effects on vital signs, shoulder fatigue, and shoulder pain. The HAL decreased muscle activity levels, with a 55% decrease in trapezius muscle activity. The upward rotation angle of the scapula was significantly lower with the HAL at 120° of shoulder flexion. CONCLUSION: The single-joint HAL provided safe and effective assistance to scapular plane shoulder flexion-extension among healthy adults.

The voluntary driven exoskeleton Hybrid Assistive Limb (HAL) for postoperative training of thoracic ossification of the posterior longitudinal ligament: a case report.

CONTEXT: The hybrid assistive limb (HAL) is a wearable robot suit that assists in voluntary control of knee and hip joint motion by detecting bioelectric signals on the surface of the skin with high sensitivity. HAL has been reported to be effective for functional recovery in motor impairments. However, few reports have revealed the utility of HAL for patients who have undergone surgery for thoracic ossification of the posterior longitudinal ligament (thoracic OPLL). Herein, we present a postoperative thoracic OPLL patient who showed remarkable functional recovery after training with HAL. FINDINGS: A 63-year-old woman, who could not walk due to muscle weakness before surgery, underwent posterior decompression and fusion. Paralysis was re-aggravated after the initial postoperative rising. We diagnosed that paralysis was due to residual compression from the anterior lesion and microinstability after posterior fixation, and prescribed bed rest for a further 3 weeks. The incomplete paralysis gradually recovered, and walking training with HAL was started on postoperative day 44 in addition to standard physical therapy. The patient underwent 10 sessions of HAL training until discharge on postoperative day 73. Results of a 10-m walk test were assessed after every session, and the patient's speed and cadence markedly improved. At discharge, the patient could walk with 2 crutches and no assistance. Furthermore, no adverse events associated with HAL training occurred. CONCLUSION: HAL training for postoperative thoracic OPLL patients may enhance improvement in walking ability, even if severe impairment of ambulation and muscle weakness exist preoperatively.