The state of the art in beyond 5G distributed massive multiple-input multiple-output communication system solutions.

Beyond fifth generation (5G) communication systems aim towards data rates in the tera bits per second range, with improved and flexible coverage options, introducing many new technological challenges in the fields of network architecture, signal pro- cessing, and radio frequency front-ends. One option is to move towards cell-free, or distributed massive Multiple-Input Multiple-Output (MIMO) network architectures and highly integrated front-end solutions. This paper presents an outlook on be- yond 5G distributed massive MIMO communication systems, the signal processing, characterisation and simulation challenges, and an overview of the state of the art in millimetre wave antennas and electronics.

Outcomes of reconstructive hand surgery in patients with tetraplegia and neuropathic pain.

STUDY DESIGN: Retrospective cohort study OBJECTIVES: To evaluate the impact of preoperative neuropathic pain on outcome and postoperative compliance after grip reconstructive surgery in people with tetraplegia. SETTING: Specialized tetraplegia upper-limb surgery center in Sweden. METHODS: All patients who underwent grip reconstructive surgery and attended a 6 month follow up during January 2012 and May 2015 were included. Participants were divided into two groups, pain group and no pain group, based on preoperative rating of experienced pain on a visual analog scale. The main outcome measures were grip strength, grasp ability (Grasp and Release Test) and prioritized activity outcome (Canadian Occupational Performance Measure) together with compliance to the rehabilitation plan. RESULTS: The study include 37 patients (86% of the cohort). Seventeen patients experienced preoperative pain (46%). There were no differences in outcome between the pain- and the no pain group regarding grip strength (5 vs. 4.6 kg), grip ability or activity performance and satisfaction (COPM improvement of 3.1 vs. 3.0 for performance and 3.6 for both groups in satisfaction). Both groups experienced improvements in all aspects and there were no differences in the ability to fulfill postoperative treatment. CONCLUSIONS: Individuals with tetraplegia and preoperative neuropathic pain in the arm/hand improve after grip reconstructions in a similar way to those without pain. Patients with neuropathic pain therefore should be considered as surgery candidates to the same extent as those without pain.

Morphological patterns of the pretendinous cord in Dupuytren's disease: a predictor of clinical outcome?

The morphology of the pretendinous cord in Dupuytren's disease is poorly described in vivo and especially with respect to recurrence after treatment. This prospective study was designed to describe the morphology of Dupuytren's cords by ultrasound and to identify possible correlation between the ultrasonographic characteristics of these cords and the clinical outcomes two years after treatment. Thirty-nine patients with a contracture of at least 20° in the metacarpophalangeal (MCP) joint, who were scheduled for local treatment by either injectable collagenase clostridium histolyticum (CCH) or percutaneous needle fasciotomy (PNF), were examined by ultrasound. The echogenicity and position of the pretendinous cords in relation to flexor tendons and neurovascular bundles were categorized. The structure of the cords was described and characterized as predominantly nodular or fibrillar. All 39 patients were assessed clinically after two years. A majority of the patients (84%) had cords with nodular components, and six patients (16%) had fibrillar cords. After two years, the clinical results were compared to the ultrasonographic findings before treatment. Three patients had recurrent contracture, and a retrospective analysis showed that all of these patients had cords with mixed echogenicity and nodules before treatment. Fifteen patients had a palpable pretendinous cord, and all but one of these had cords with mixed echogenicity and nodular structure before treatment. This pilot study indicates that some ultrasonographic features of the Dupuytren's cord, such as mixed echogenicity and nodular structure, may predict recurrence after minimally invasive treatment for Dupuytren's contracture. However, a larger study in correlation with histological examination of the excised cords would be necessary to confirm the pathoanatomical significance of these ultrasonographic features.

Ultrasonographic examination of the ruptured cord after collagenase treatment or needle fasciotomy for Dupuytren's contracture.

Local treatment of Dupuytren's contracture, either by collagenase or needle fasciotomy, allows disruption of the pathological cord during forced extension. The purpose of this study was to investigate the cord before and after both treatments by ultrasound. A total of 39 patients with a minimum of 20° contracture in the metacarpophalangeal joint were included and randomized to treatment with either collagenase (20 patients) or needle fasciotomy (19 patients). The distance between the distal and the proximal parts of the ruptured cord was measured by ultrasound and the difference in passive joint movement before and after treatment was measured with a goniomenter. There were no significant differences between the collagenase and needle fasciotomy groups in the size of the rupture or gain of mobility. Most cords treated with collagenase and subsequent forced extension had the same ultrasonographic appearance as cords disrupted mechanically by needle fasciotomy. LEVEL OF EVIDENCE: III.

Essential gains and health after upper-limb tetraplegia surgery identified by the International classification of functioning, disability and health (ICF).

STUDY DESIGN: A questionnaire-based survey. OBJECTIVES: To describe functional gains and health following upper-limb tetraplegia surgery using the International Classification of Functioning, Disability and Health (ICF) as a reference and to explore interconnections across different dimensions of functioning and health. SETTING: A specialized center for advanced reconstruction of extremities at Sahlgrenska University Hospital, Gothenburg, Sweden. METHODS: Fifty-seven individuals who participated in a satisfaction survey were included in the present study. Besides questions concerned with the respondents' satisfaction with different aspects of surgery, the measures included perceived overall health status (EQ-VAS) and achieved grip strength. Univariate analyses were used to explore interconnections between measures. RESULTS: The gains could be subcategorized and linked to the ICF domains 'mobility', 'self-care', 'communication', 'domestic life', and 'community, social and civic life', with 'handling objects' and 'maneuvering a wheelchair' as the most frequently reported gains. The mean EQ-VAS score was 67±22. No significant correlation was shown between grip strength and activity gains, nor between grip strength and perceived overall health. The degree of satisfaction was, however, associated with self-reported overall health among participants. CONCLUSION: The functional gains achieved after tetraplegia surgery could be applied to the ICF constructs' body functions/structures and activity with possible implications on participation. The overall health perception was relatively high and could be linked to the degree of satisfaction among participants. Muscle strength is not necessarily transferable to activity performance. This emphasizes the importance of addressing factors other than strength in the post-surgical rehabilitation and assessments.

Satisfaction with upper limb reconstructive surgery in individuals with tetraplegia: the development and reliability of a Swedish self-reported satisfaction questionnaire.

STUDY DESIGN: A questionnaire-based survey. OBJECTIVES: To assess satisfaction after upper limb reconstructive surgery in individuals with tetraplegia and to determine the reliability of a Swedish satisfaction questionnaire. SETTING: A center for advanced reconstruction of extremities, Gothenburg, Sweden. METHODS: Seventy-eight individuals with tetraplegia were invited to participate in the survey assessing satisfaction with the result of surgery across various domains. Measures of reliability included stability and internal consistency of domains consisting questions regarding global satisfaction, activities and occupation/schooling. RESULTS: Fifty-eight individuals (76%) participated, among whom 47 (82%) completed the questionnaire twice for repeatability assessment. The responses in the domains relating to global satisfaction, activities and occupation/schooling were positive in 83%, 72% and 31% of participants, respectively. Ninety-five percent felt they had benefited from the surgery, and 86% felt that the surgery had made a positive impact on their life. The psychometric testing indicated that the questionnaire yields scores that are reliable by both test-retest and internal consistency, with the exception of the domain occupation/schooling that had a high prevalence of missing and neutral responses and seemingly represents separate and distinct entities. CONCLUSION: Surgical rehabilitation of the upper limb in tetraplegia is highly beneficial and rewarding from a patient perspective, leading to satisfactory gains in activities of daily living as well as enhanced quality of life. The questionnaire is a reliable instrument for measuring satisfaction after surgery. However, occupationally and educationally related aspects of the surgical outcome should constitute separate domains, and further modifications of the questionnaire are thus recommended.

Patients with triangular fibrocartilage complex injuries and distal radioulnar joint instability have reduced rotational torque in the forearm.

UNLABELLED: A total of 20 patients scheduled for wrist arthroscopy, all with clinical signs of rupture to the triangular fibrocartilage complex and distal radioulnar joint instability, were tested pre-operatively by an independent observer for strength of forearm rotation. During surgery, the intra-articular pathology was documented by photography and also subsequently individually analysed by another independent hand surgeon. Arthroscopy revealed a type 1-B injury to the triangular fibrocartilage complex in 18 of 20 patients. Inter-rater reliability between the operating surgeon and the independent reviewer showed absolute agreement in all but one patient (95%) in terms of the injury to the triangular fibrocartilage complex and its classification. The average pre-operative torque strength was 71% of the strength of the non-injured contralateral side in pronation and supination. Distal radioulnar joint instability with an arthroscopically verified injury to the triangular fibrocartilage complex is associated with a significant loss of both pronation and supination torque. LEVEL OF EVIDENCE: Case series, Level IV.

The mechanical strength of side-to-side tendon repair with mismatched tendon size and shape.

Tendon transfers frequently require coaptation of two mismatched tendons. In this cadaver study, ultimate load, stiffness, and Young's modulus were measured in tendon-to-tendon attachments with mismatched donor and recipient tendons, using pronator teres (PT) to extensor carpi radialis brevis (ECRB) and flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC). FCU-to-EDC attachments failed at higher loads than PT-to-ECRB attachments, but they had similar modulus and stiffness values. Ultimate tensile strength of the tendon attachments exceeded the maximum predicted contraction force of any of the transferred muscles, with safety factors of four-fold for the FCU-to-EDC and two-fold for the PT-to-ECRB transfers. This implies that size and shape mismatches should not be contraindications to tendon attachment in transfers. The strength safety factors suggest that postoperative immobilization of these transfers is unnecessary.

International spinal cord injury upper extremity basic data set.

OBJECTIVE: To develop an International Spinal Cord Injury (SCI) Upper Extremity Basic Data Set as part of the International SCI Data Sets, which facilitates consistent collection and reporting of basic upper extremity findings in the SCI population. SETTING: International. METHODS: A first draft of a SCI Upper Extremity Data Set was developed by an international working group. This was reviewed by many different organisations, societies and individuals over several months. A final version was created. VARIABLES: The final version of the International SCI Upper Extremity Data Set contains variables related to basic hand-upper extremity function, use of assistive devices, SCI-related complications to upper extremity function and upper extremity/hand reconstructive surgery. Instructions for data collection and the data collection form are freely available on the ISCoS website (www.iscos.org.uk). CONCLUSION: The International SCI Upper Extremity Basic Data Set will facilitate consistent collection and reporting of basic upper extremity findings in the SCI population.

Distal radio-ulnar joint instability in children and adolescents after wrist trauma.

UNLABELLED: This study retrospectively evaluated the medical records and radiographs of patients younger than aged 25 that were referred for a second opinion due to ulnar-sided wrist pain and persistent distal radio-ulnar (DRU) joint instability. We identified 85 patients with a major wrist trauma before the age of 18. Median age at trauma was 14 years. Median time between trauma and diagnosis of DRUJ instability was 3 years. Sixty-seven patients (79%) had sustained a fracture at the initial trauma. The two most common skeletal injuries related to the DRUJ instability were Salter-Harris type II fractures (24%) and distal radius fractures (19%). In 19 patients (22%), the secondary DRUJ instability was caused by malunion or growth arrest. Eighteen patients (21%) had no fracture; in spite of this, they presented with subsequent symptomatic DRUJ instability. Fourteen of these 18 patients had a triangular fibrocartilage complex (TFCC) tear, confirmed by arthroscopy, open surgery, or magnetic resonance imaging. In conclusion, late DRUJ instability due to wrist fractures or isolated TFCC tears was found to be common in children and adolescents. LEVEL OF EVIDENCE: IV.

How to treat Guyon's canal syndrome? Results from the European HANDGUIDE study: a multidisciplinary treatment guideline.

BACKGROUND: Although Guyon's canal syndrome is not highly prevalent, a considerable knowledge of anatomy is needed to localise and treat the pathology. Data on the effectiveness of interventions for this disorder are lacking. OBJECTIVE: To achieve consensus on a multidisciplinary treatment guideline for this disorder based on experts' opinions. METHODS: A European Delphi consensus strategy was initiated. In total, 35 experts (hand surgeons/hand therapists selected by the national member associations of their European federations and Physical Medicine and Rehabilitation physicians) participated in the Delphi consensus strategy. Each Delphi round consisted of a questionnaire, an analysis and a feedback report. RESULTS: After three Delphi rounds, consensus was achieved on the description, symptoms and diagnosis of Guyon's canal syndrome. The experts agreed that patients with this disorder should always receive instructions and that these instructions should be combined with another form of treatment. Instructions combined with splinting or with surgery were considered as suitable treatment options. Details on the use of instructions, splinting and surgery were described. Main factors for selecting one of the aforementioned treatment options were identified: severity and duration of the syndrome and previous treatments given. A relation between the severity/duration and choice of therapy was indicated by the experts and reported in the guideline. CONCLUSIONS: Although this disorder is less prevalent and not easy to diagnose, this guideline may contribute to better insight into and treatment of Guyon's canal syndrome.

Rebalancing the tetraplegic wrist using extensor carpi ulnaris-tenodesis.

Patients with cervical spinal cord injury and tetraplegia often present with a radial deviation deformity of the wrist owing to impaired active wrist flexion and extension. Tenodesis of the extensor carpi ulnaris can help optimize grip strength. The purpose of the study was to compare reconstruction of the grip with and without extensor carpi ulnaris-tenodesis, as well as evaluating the outcome of the procedure. The grip strength of the group with tenodesis of the extensor carpi ulnaris was twice as strong as of the group without the tenodesis and with similar wrist joint flexion-extension range of motion. Correction of the wrist deformity enables a more ergonomic use of the hand. This may also help prevent shoulder pain, which is common among patients with tetraplegia.

Restoration of active palmar abduction of the thumb in tetraplegia by tendon transfer of the extensor digiti minimi to abductor pollicis brevis.

We describe a method to restore active palmar abduction of the thumb and report its functional impact in tetraplegia. At 54.2 (SD 42.8) months after cervical spinal cord injury (12 traumatic, 3 nontraumatic), the extensor digiti minimi (EDM) tendon was transferred to the abductor pollicis brevis (APB) through the interosseous membrane in 15 tetraplegic patients (age range 19-70 years) in addition to a mean 3.2 procedures to restore key pinch. According to International Classification, the operated upper extremities were in the OCu4 to OCu8 (1 patient X) group. The maximum distance between thumb and index finger tips during active or passive opening of the hand, maximum angle of palmar abduction, grip and key pinch strength, and active finger range of motion were measured. All patients were re-examined after 38.4 (SD 22.7) months. The active thumb-index opening increased significantly from 2.5 (SEM 1.0) cm before to 9.0 (SEM 0.8) cm after surgery. Nine patients without previous active opening of the first web space recovered a mean thumb-index opening of 9.1 (SEM 1.7) cm, whereas this distance increased by an average of 2.9 (SEM 0.8) cm in six patients who had active thumb index distance of 6.3 (SEM 1.6) cm before surgery. All but one patient were able to direct and coordinate key pinch and perform tasks using the restored APB function, including five patients whose EDM strength was rated as grade 3 before transfer. This EDM-to-APB transfer meets the theoretical requirements of architecture matching between donor and recipient muscles, the principles of tendon transfer, and our surgical expectations. We strongly recommend that an active EDM is transferred to the APB to restore opening of the hand and help in key pinch control in patients with tetraplegia.

Simultaneous powering of forearm pronation and key pinch in tetraplegia using a single muscle-tendon unit.

This study clinically assessed the concept that both thumb flexion and forearm pronation can be restored by brachioradialis (BR)-to-flexor pollicis longus (FPL) tendon transfer if the BR is passed dorsal to the radius. Six patients [two women and four men, mean age 32.3 years (SD 4.9, range 23-56)] underwent BR-to-FPL transfer dorsal to the radius and through the interosseous membrane (IOM). Lateral key pinch strength and pronation range of motion (ROM) were measured 1 year after surgery. A group of six patients [two women and four men, mean age 31.2 years (SD 5.0, range 19-52)] who underwent traditional palmar BR-to-FPL was included for comparison. Postoperative active pronation was significantly greater in the dorsal transfer group compared to the palmar group [149 (SD 6) and 75 (SD 3), respectively] and pinch strength was similar in the two groups [1.28 (SD 0.16) kg and 1.20 (SD0.21) kg, respectively]. We conclude that it is feasible to reconstruct lateral key pinch and forearm pronation simultaneously using only the BR motor.

Satisfaction and performance in patient selected goals after grip reconstruction in tetraplegia.

Reconstruction of grip in tetraplegia aims to improve upper extremity performance and control in daily life. We evaluated the effects of surgery and rehabilitation on performance and satisfaction of patient identified activity goals in 20 patients (22 arms) who had grip reconstructions for both finger and thumb flexion. Patients assessed an improvement in both performance and satisfaction after surgery in all groups of activities assessed using the Canadian Occupational Performance Measure (COPM). The mean improvement at 6 and 12 months was 3.5 points better than the 2.5 points before surgery. Before surgery 36% of the goals identified were impossible to perform. After surgery, 78% of these goals were possible. The largest improvement was observed in the basic activity of 'eating' but significant improvement was also noted in activities generally regarded as complex and not measured in standard ADL such as 'doing housework' and taking part in 'leisure'.

Structural characteristics of the subscapularis muscle in children with medial rotation contracture of the shoulder after obstetric brachial plexus injury.

The aim of this study was to obtain a better understanding of the cause of the medial rotation contracture of the shoulder after obstetric brachial plexus lesions by studying the morphology of the shortened subscapularis muscle. Muscle biopsy specimens were harvested from 13 children with obstetric brachial plexus palsy who underwent corrective surgery for the rotation contracture. The majority of the subscapularis muscle biopsy samples had an essentially normal morphology and showed a predominance of type I myosin heavy chain isoform, while one biopsy showed signs of marked fibrosis and a predominance of type II myosin heavy chain isoform. The findings support the assumption that shortening of the subscapularis is caused primarily by the nerve injury, which weakens the antagonistic lateral rotators, but that direct injury to the muscle might be a contributory factor.

Acceptable benefits and risks associated with surgically improving arm function in individuals living with cervical spinal cord injury.

STUDY DESIGN: Secure, web-based survey. OBJECTIVES: To determine how quadriplegics in the US view tendon transfer surgeries (TTS) and what activities of daily living (ADL) involving arm/hand function are important in improving quality of life (QoL). SETTING: World wide web. METHODS: Individuals >or=18 years of age living with a cervical spinal cord injury (SCI). Participants obtained a pass code to enter a secure website and answered survey questions. A total of 137 participants completed the survey. RESULTS: Two-thirds of participants had injury levels between C4/5 and C5/6. Over 90% felt that improving their arm/hand function would improve their QoL. ADL that were ranked most important to regain were dressing, feeding, transferring in/out of bed, and handwriting. Less than half of the participants had never been told about TTS and only 9% had ever had TTS. Nearly 80% reported that they would be willing to spend 2-3 months being less independent, while recovering from surgery, to ultimately become more independent. Over 75% reported that the ideal time preferred to have TTS, if chosen, would be within 5 years post-injury. CONCLUSION: Regaining arm and hand function is of primary importance to individuals with cervical SCI, in particular, to increase independence in multiple ADL. There is a critical need in the US to improve awareness of TTS as a viable option for improving arm/hand function in some people. This information needs to be provided early after injury so that informed choices can be made within the first 5 years.

Subscapularis muscle mechanics in children with obstetric brachial plexus palsy.

This study investigates the passive mechanical properties of the subscapularis muscle in children with a contracture as a result of obstetrical brachial plexus palsy. Muscle biopsies were harvested from nine children undergoing open surgery for shoulder contracture. Passive mechanical testing of single cells and muscle bundles was performed. Corresponding comparisons were made using muscle biopsies from seven healthy controls. Single muscle fibres from patients with obstetric brachial plexus palsy displayed a shorter slack sarcomere length, linear deformation of the fibre within a wider zone of sarcomere length and a greater relative increase in stiffness compared with muscle bundles. We conclude that secondary changes in muscle fibre properties will occur as a result of a longstanding lack of sufficient passive stretch, leading to compensatory changes in the extracellular matrix. These results suggest the presence of a dynamic feedback system constituting a muscle-to-extracellular matrix communication interface.