Hand Reconstruction Research Articles

Advances in vision-based deep learning methods for interacting hands reconstruction: A survey

Vision-based hand reconstructions have become noteworthy tools in enhancing interactive experiences in various applications such as virtual reality, augmented reality, and autonomous driving, which enable sophisticated interactions by reconstructing complex motions of human hands. Despite significant progress driven by deep-learning methodologies, the quest for high-fidelity interacting hands reconstruction faces challenges such as limited dataset diversity, lack of detailed hand representation, occlusions, and differentiation between similar hand structures. This survey thoroughly reviews deep learning-based methods, diverse datasets, loss functions, and evaluation metrics addressing the complexities of interacting hands reconstruction. Mainstream algorithms of the past five years are systematically classified into two main categories: algorithms that employ explicit representations, such as parametric meshes and 3D Gaussian splatting, and those that utilize implicit representations, including signed distance fields and neural radiance fields. Novel deep-learning models like graph convolutional networks and transformers are applied to solve the aforementioned challenges in hand reconstruction effectively. Beyond summarizing these interaction-aware algorithms, this survey also briefly discusses hand tracking in virtual reality and augmented reality. To the best of our knowledge, this is the first survey specifically focusing on the reconstruction of both hands and their interactions with objects. The survey contains the various facets of hand modeling, deep learning approaches, and datasets, broadening the horizon of hand reconstruction research and future innovation in natural user interactions.

Dorsal Carpal Artery Perforator Flaps: An Anatomical and Clinical Study.

Hand injuries pose challenges due to complexity and aesthetic-functional concerns. Dorsum of hand injuries are difficult to treat due to thin skin cover and increased propensity to exposure of underlying structures. Perforator-based flaps can provide better outcomes with minimal donor site morbidity. This study aims to bridge the gap in anatomical knowledge and explore the potential benefits of dorsal carpal artery perforator flap. A prospective study was done from July 2021 to June 2023, focused on study of dorsal carpal artery perforators on 12 fresh frozen cadaveric hands. Anatomical study involved injection of red latex into arteries at the wrist, followed by dissection and measurements. During the clinical phase, we used the inferences gained from the anatomical study to identify and mark perforator of dorsal carpal arteries. We performed V-Y advancement flap based on the DCPs in 5 patients who had dorsum of hand defects due to trauma. The study was carried out on 6 fresh frozen cadavers (12 hands). Anatomical findings revealed the anatomical location, caliber, and consistent number of dorsal carpal artery perforators supplying the dorsum of the hand arranged in 2 rows. Clinically, we applied this insight to create V-Y flaps in 5 patients with successful outcomes, thus, offering DCP-based flap as an alternative to distant flaps. DCP-based flaps offer an efficient solution for reconstructing proximal hand defects over the dorsum, with minimal complications, enhancing our understanding of hand reconstruction options. The study's comprehensive anatomical insights and clinical outcomes contribute to improving hand defect management and surgical techniques.

Expected outcome for reconstructive hand surgery after spinal cord injuries related to level of injury and sex.

This retrospective, multicentre study maps grip strength and grasp ability after tendon transfer surgery in patients with tetraplegia. Data were analysed in the whole group and in subgroups stratified into the International Classification for Surgery of the Hand in Tetraplegia (ICSHT) and sex. In total, 200 arms (143 patients) had tendon transfer surgery to restore grip and pinch function, 74% were men, 42% were ICSHT group ≤3 and 58% ICSHT were group ≥4. The one-year outcome across all participants for grip strength was 5.2 kg, pinch strength 2.1 kg and a score of 108 for the Grasp and Release test. Men had significantly higher grip and pinch strength compared to women, while there was no significant difference with respect to grasp ability. ICSHT group ≥4 had significantly higher grip strength and grasp ability compared to ICSHT group ≤3, whereas no significant difference in pinch strength between ICSHT groups was seen.Level of evidence: III.

DISTANT SOFT TISSUE FLAPS IN A DEGLOVING SKIN INJURY

Avulsion skin injuries of the glove removal type are one of the most challenging and difficult problems in reconstructive hand surgery. Immediate or early coverage of the hand is of utmost importance. Several options are proposed for early covering the preserved structures (tendons, bones and nerves) early, mainly skin grafting on the preserved viable structures. Case description: We present a case of a patient with 4th and 5th finger crushing and avulsion skin injury of thumb and index finger and lost distal phalanges. The 4th and 5th fingers had been amputated due to gangrene. Two anterior abdominal wall flaps were applied: a thoraco-umbilical flap and a horizontal Filatov stem" flap. On the 25th day, the flaps were separated from the fingers and following commissuroplasty 10 months later. Result: Fusion between the donor flap and the recipient structures was obtained without clinical evidence of infection, ulceration and flap necrosis. Conclusions: The usage of remote skin flaps is a safe and simple method to restore hand function when microsurgery cannot be applied.

Vascularized Bone Graft in Mangled Hand Reconstruction

Extensive bone defects especially in conjunction with associated coverage involvement in mangled hands, pose significant challenges to hand and upper extremity surgeons. Vascularized bone grafts often play a vital role for effective treatment now-a-days. It not only bypasses the drawbacks of conventional grafts but also allows for simultaneous one stage reconstruction of its coverage as well as repairs other injured structures.Preoperative evaluation of mangled hand is crucial, the injury extent, including circulation, patient expectations and clinical reality should be all taken into consideration before finalizing the reconstruction plan. The fibula bone and other vascularized bone flaps such as iliac crest bone and medial femoral condyle and some others as well as corresponding spare part can provide effective solutions. Especially important considerations about surgeons’ experience and expertise , donor site morbidity , postoperative care and rehabilitation are essential for optimal outcomes. In this article , we would like to share our current practicing vascularized bone flaps in mangled hand reconstructions.

Functional Restoration of Bilateral Wrist Level Hand Amputee with Six-Toe Transfers and Three Free Flaps: An Alternative to Hand Allotransplantation or Prosthesis

Abstract Introduction Hand amputation at the wrist level is severely disabling, especially when bilateral. It is paramount to restore the hand function to the best possible level for the patient's daily living activities, as well as optimal social and occupational rehabilitation. There are various options for restoration of function after amputation at wrist and distal forearm levels including Krukenberg's operation, variations of toe transfers, hand allotransplantation, and prosthesis. Krukenberg's procedure and the reconstruction using toe transfer like Vilkki's procedure or two-toe transfers, restore only the pinch. Hand allotransplantation, although it gives excellent function, has limitations due to the complications of immunosuppression. Functional hand prosthesis, though superior in cosmetic appearance, have again limitations in function, and the cost is prohibitive for most patients in our country. Materials and Methods We present the unique case of a bilateral hand amputation at the wrist level reconstructed with three toes and free anterolateral thigh (ALT) flap in a single-stage surgery for each hand. In two stages, the patient had six toes transferred to both hands. Result All transferred toes and all three free (two ALT and one thoracodorsal artery perforator) flaps survived completely. Three-finger grip (tripod pinch) was thus restored in each hand. The hook grip was also restored well by the reconstructed two fingers. Within 3 months after surgery, the patient could perform all activities of daily living. He resumed his original job with some modification of his work within 6 months postinjury. Conclusion Hand reconstruction using three toes and a free flap is an excellent option for functional restoration for amputation at the wrist and distal forearm level. It allows an early return to function and good social and professional integration of the patient. This procedure is a potential alternative to expensive prosthesis and allotransplantation for a bilateral hand amputation.

Reconstruction of Total Hand Degloving Injury with Combined Free and Pedicled Flaps and Ilizarov Minifixator.

Total hand degloving injuries present a significant challenge in treatment, with no consensus yet on the optimal choice of flap for coverage. Functional reconstruction necessitates careful consideration of syndactyly release, particularly after flap coverage. A 64-year-old woman sustained a total hand degloving injury and underwent extensive reconstructive surgery. Initially, a free superficial circumflex iliac perforator flap was applied to the thumb, whereas pedicled groin and superficial inferior epigastric artery flaps were used for the remaining fingers. However, partial necrosis at the edges of the pedicled flaps necessitated the adduction of the fingers, followed by suturing the skin flaps closed. This led to the formation of adduction contractures, requiring careful release and skin flap extension for effective syndactyly release. Subsequently, the innovative use of an Ilizarov minifixator was used for the dual purpose of interdigital widening and elongation of the flap. At the 27-month follow-up, the patient demonstrated significant functional recovery of the hand and fingers, showing the effectiveness of this multifaceted surgical approach. Despite some residual flexion contractures, the patient regained the ability to write and perform pinching motions with the thumb and middle finger, expressing satisfaction with the surgical outcome. In conclusion, for a functional reconstruction of the thumb and fingers, the thumb and other fingers should be covered separately. When the fingers are in adduction and there is insufficient skin stock for syndactyly release, using an external fixator to expand the interdigital spaces before the syndactyly release proved to be effective.

Paraffinoma of the hands: a case report

Paraffin injection has been widely used to improve body contouring or to augment various body parts, although it has now been abandoned owing to serious complications. Paraffin injection may lead to complications after a long latency period, ranging from several years to several decades. Here, we present the rare case of a 77-year-old woman who suffered from recurrent wound problems after a bilateral paraffin injection into her hands 40 years ago. Initially, conservative debridement was carried out due to the patient’s reluctance to undergo extensive surgery and cost concerns. However, this resulted in recurrent wound dehiscence and infection. After serial debridement procedures, a skin graft was performed on her right hand. The patient complained of a depressed contour and numbness at the skin graft site, and tightness and discomfort of her right hand during flexion of the metacarpophalangeal joint. Three years later, the patient presented with a highly similar wound on her left hand. Thorough excision of the soft tissue infiltrated by paraffin was performed, followed by reconstruction using a sensate free anterolateral thigh flap. The patient responded well postoperatively without complications, displaying a fair range of motion without discomfort, sensory restoration of the flap, and satisfaction with the contour of the dorsum. This case report highlights the importance of complete excision of soft tissues infiltrated by paraffin for definitive treatment. Among the various reconstruction options, a sensate free flap is a good choice for achieving favorable functional and esthetic outcomes in hand reconstruction after radical excision of a paraffinoma.

Progress toward the Definition of X-ray Computed Tomography Accuracy in the Characterization of Polymer-Based Lattice Structures.

Lattice structures have become an innovative solution for the improvement of part design, as they are able to substitute solid regions, maintain mechanical capabilities, and reduce material usage; however, dimensional quality control of these geometries is challenging. X-ray computed tomography (XCT) is the most suitable non-destructive metrological technique as it is capable of characterizing internal features and hidden elements. Uncertainty estimation of XCT is still in development, and studies typically use high-resolution calibrated devices such as focal variation microscopes (FVMs) as a reference, focusing on certain parts of the lattice but not the whole structure. In this paper, an estimation of the accuracy of XCT evaluation of a complete lattice structure in comparison to a higher-resolution reference device (FVM) is presented. Experimental measurements are taken on ad hoc designed test objects manufactured in polyamide 12 (PA12) using selective laser sintering (SLS), optimized for the evaluation on both instruments using different cubic-based lattice typologies. The results confirm higher precision on XCT evaluation in both qualitative and quantitative analysis. Even with a lower resolution, XCT is able to characterize details of the surface such as re-entrant features; as well, standard deviations and uncertainties in strut diameter evaluation remain more stable in all cells in XCT, identifying on the other hand reconstruction problems on FVM measurements. Moreover, it is shown that, using XCT, no additional evaluation errors were found in inner cells, suggesting that the measurement of external elements could be representative of the whole structure for metrological purposes.

Flow-Through Procedure in Sequela After Complex Injuries of the Hand With Fingers’ Amputation

PurposeComplex injuries of the hand with finger amputation can result in important functional impairment. If the amputated fingers cannot be replanted, the developed sequelae should be further evaluated. Sometimes, in the presence of a few remaining local vascular resources, the use of the flow-through technique can help in solving the problem. MethodsThis study retrospectively reviews 4 cases who underwent single or multiple fingers reconstruction with toe transfers by using true flow-through or flow-through conduit flaps. A thorough description of the two methods is done, and the quality of the regained functionality of the hand is presented. ResultsAll the patients were males, aged between 21 and 45 (median age 31.75). One of them injured the left dominant hand, and the other three their right dominant hand. The median time between the accident and reconstructive surgery was 14.5 months (range, 3 months-36 months). All the initial lesions were work-related trauma. One patient had severe sequela after forearm compartment syndrome and amputation of the thumb and fifth finger; one patient had a metacarpal hand, one patient had amputation of two fingers (2nd and 4th); and one patient had three fingers amputated (2nd, 3rd, and 4th). In the first patient, a true flow-through flap and a second toe transfer was done, and in the other three patients multiple toe transfers by using the flow-through conduit technique were used. A good functionality of the reconstructed hand was obtained in all the patients. ConclusionsToe transfer remains one of the best methods in the reconstruction of hands with missing fingers. The use of both true flow-through flap and flow-through conduit methods are very useful, especially in cases with few vascular resources.

Survey-based Study to Assess the Self-perceived Competency in and Knowledge about Reconstructive Microsurgery among Young Plastic Surgeons

Objective: Microvascular free tissue transfer has become a preferred reconstructive technique for managing complex wounds and defects. The aim of this questionnaire-based study was to assess self-perceived competency in and knowledge about reconstructive microsurgery among plastic surgeons who graduated from the Faculty of Medicine Siriraj Hospital, Mahidol University during 2015-2019. Materials and Methods: Questionnaire was sent by email elicited information about the amount of microsurgery performed in practice, types of microsurgeries performed, reconstructive methods, types of flaps used, and respondent’s opinion about the microsurgery course attended during residency/fellowship training. Results: The total response rate was 87.5%. Almost all respondents work in a government hospital (90.4%), and responses came from all regions of Thailand. Thirty-eight percent of respondents reported no microsurgery cases, and the majority of those who did perform microsurgery did so less than 20 times/year. Hand reconstruction was the most common type of microsurgical procedure. The factors that negatively influence microsurgery in clinical practice include insufficiency of resources and personnel (29.1%), excessive workload (27.3%), and long operative time (23.6%). Suggestions for improvement of the microsurgical training course include having a good objective method for assessing microsurgical practices (27.7%), increasing the volume of practice on animal model (25.5%), and an appropriate number of microsurgery cases to gain necessary experience (25.5%). Conclusion: Reconstructive microsurgery was found to be a challenging procedure for many junior-level plastic surgeons. A low volume of cases limits a surgeon’s ability to develop needed skills. Important improvements in the microsurgery training course were also recommended.

3D hand pose estimation and reconstruction based on multi-feature fusion

3D hand pose estimation and shape reconstruction is to recover the hand joint points and hand mesh vertices coordinates from the image. However, existing methods usually only use the high-level semantic features extracted by the backbone network to represent the hand mesh vertex features, which leads to a single representation of the hand vertices features and cannot fully utilize the feature information extracted by the network. In this paper, we propose a method for real-time 3D reconstruction of hands from a single RGB image, which enriches the 3D semantic information of the mesh vertices through multi-feature fusion. Firstly, we regress the 2D features of mesh vertices through Integral Pose Regression (IPR) and regard them as prior information to 3D features. Then we design a Multi-Scale Sampling(MSS) module to extract multi-scale information. Finally we fuse 2D prior features, multi-scale features, and high-level semantic features extracted by backbone to represent 3D initial feature. Additionally, we propose a Multi-Root(MR) loss function to address the imbalance problem caused by a single root joint. The experimental results indicate that our network achieves competitive performance on the FreiHAND and HO-3D public datasets, achieving fast inference speed with fewer parameters.

Coarse-to-fine cascaded 3D hand reconstruction based on SSGC and MHSA

Coarse-to-fine cascaded 3D hand reconstruction based on SSGC and MHSA

Midterm Outcomes of Surgical Reconstruction and Spontaneous Recovery of Upper-Extremity Paralysis Following Acute Flaccid Myelitis.

Acute flaccid myelitis (AFM) is a disabling, poliomyelitis-like illness that mainly affects children. Although various surgical interventions are performed for intractable paralysis due to AFM, the timing of surgery and its long-term outcomes have yet to be established, especially for shoulder reconstruction. This study aimed to analyze the midterm outcomes of nonsurgically and surgically treated upper-extremity AFM and the factors influencing shoulder functional outcomes after surgical reconstruction. We retrospectively examined 39 patients with AFM in 50 upper extremities between 2011 and 2019. The degree of spontaneous recovery of completely paralyzed muscles was evaluated at a median of 3, 6, and 37 months after the onset of paralysis. Twenty-seven patients with 29 extremities underwent surgery involving nerve transfer, muscle-tendon transfer, or free muscle transfer for shoulder, elbow, and hand reconstruction. Patients with complete paralysis of shoulder abduction at 6 months did not show later recovery. Twenty-two patients with 24 extremities underwent shoulder surgery, and all but 1 were followed for at least 24 months after surgery. Although postoperative shoulder abduction recovery was similar between transfer of the spinal accessory nerve and of the contralateral C7 nerve root to the suprascapular nerve, the outcomes obtained with spinal accessory nerve transfer had more variability, likely related to latent spinal accessory nerve paralysis, shoulder instability related to pectoralis major paralysis, and the type of paralysis. Shoulder abduction recovery was also greatly affected by scapulothoracic joint movement. In contrast, the outcomes of the elbow flexion and hand reconstructions were more consistent and acceptable. All patients had loss of shoulder abduction, and restoration of shoulder function was less predictable and depended on the quality of the donor nerves and recovery of the synergistic muscles. Strict donor nerve selection and additional nerve transfer for shoulder reconstruction are imperative for satisfactory outcomes. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

3D hand reconstruction via aggregating intra and inter graphs guided by prior knowledge for hand-object interaction scenario

Recently, 3D hand reconstruction has gained more attention in human–computer cooperation, especially for hand-object interaction scenario. However, it still remains challenge to improve estimation accuracy and ensure physical plausibility from a single RGB image. To overcome the challenge, we propose a 3D hand reconstruction network combining the benefits of model-based and model-free approaches to balance accuracy and physical plausibility for hand-object interaction scenario. Firstly, we present a novel topology-aware MANO pose parameters regression module from 2D joints directly. Moreover, we further carefully design a vertex-joint mutual graph-attention module guided by MANO to jointly refine hand meshes and joints, which model the dependencies of vertex-vertex and joint-joint and capture the correlation of vertex-joint for aggregating intra-graph and inter-graph node features respectively. The experimental results demonstrate that our method achieves state-of-the-art performance on recently benchmark datasets HO3DV2 and Dex-YCB, and outperforms all only model-based approaches or model-free approaches.

Exploiting Spatial-Temporal Context for Interacting Hand Reconstruction on Monocular RGB Video

Reconstructing interacting hands from monocular RGB data is a challenging task, as it involves many interfering factors, e.g., self- and mutual occlusion and similar textures. Previous works only leverage information from a single RGB image without modeling their physically plausible relation, which leads to inferior reconstruction results. In this work, we are dedicated to explicitly exploiting spatial-temporal information to achieve better interacting hand reconstruction. On the one hand, we leverage temporal context to complement insufficient information provided by the single frame and design a novel temporal framework with a temporal constraint for interacting hand motion smoothness. On the other hand, we further propose an interpenetration detection module to produce kinetically plausible interacting hands without physical collisions. Extensive experiments are performed to validate the effectiveness of our proposed framework, which achieves new state-of-the-art performance on public benchmarks.

Plastic Surgery in Burn Care: A Call for Enhanced Burn Surgery Training Within Plastic Surgery Residency Programs.

A 10 year cohort of patients admitted to a verified burn unit were analyzed to assess the role of plastic surgeons in the operative management of those patients. All 3843patients were admitted during this study period. Of these, 1509 of those patients underwent surgical procedures. Plastic surgeons performed 658 operations on these patients, including acute and delayed reconstruction of hand and facial burn injuries. In this population, plastic surgeons played a critical role in acute and reconstructive burn injuries in anatomically complex areas. This series illustrates the need for plastic surgery training in burn care.

Hand Reconstruction with Posterior Interosseous Flap. A Review

For the greatest functional outcome, hand reconstruction with soft tissue abnormalities requires an early, single-stage, well-vascularized cover. Since important tissues including tendons, bones, and joints are exposed, a full thickness graft is typically needed, and subsequent repair is frequently necessary. Reverse flow flaps in the posterior interosseous artery provide a flexible and dependable means of covering intricate soft tissue abnormalities in the hand in full thickness.

Hand Reconstruction Using Anterolateral Thigh Free Flap by Terminal Perforator-to-Digital Artery Anastomosis: Retrospective Analysis.

This study aimed to analyze cases of anterolateral thigh (ALT) free flap used for hand reconstruction with terminal perforator-to-digital artery anastomosis. Patients who underwent ALT free flap placement with terminal perforator-to-digital artery anastomosis for hand reconstruction between January 2011 and August 2021 were included. The number, length, and diameter of the perforators and veins, flap size, and operative time were investigated through a retrospective review of charts and photographs. The occurrences of arterial thrombosis, venous thrombosis, arterial spasm, and flap necrosis were analyzed. In total, 50 patients were included in this study. The mean diameter and length of the perforators were 0.68 mm and 3.25 cm, respectively, and the mean number of veins anastomosed was 1.88, with a mean diameter of 0.54 mm. Complications included four cases of arterial thrombosis, one case of venous thrombosis, seven cases of partial necrosis, and one case of total flap failure. Regression analysis showed that a longer perforator was associated with arterial thrombosis whereas larger flap size and number of anastomosed veins were associated with partial necrosis ( p < 0.05). The terminal perforator-to-digital artery anastomosis offers advantages in using compact free flaps with short pedicle lengths to cover small hand defects.

Limitation of microdissected thinning in free anterolateral thigh flap for hand reconstruction

BackgroundHand defects, especially complex defects involving tendon or bone exposure, are challenging to reconstruct. With the limited size and options of local flaps, the free-thinned anterolateral thigh (ALT) flap remains an excellent choice. However, many authors have described thinning procedures differently, leading to inconsistent outcomes. We present our clinical experience of immediate thinning ALT flaps depending on the anatomical structure of the perforator.Materials and methodsBetween 2007 and 2021, we used a free ALT flap in 42 cases to cover hand defects after crushing and friction injuries, burning and burn scars, and animal bite wounds. There were 38 males and 4 females; the mean patient age was 31.2 years. Thinning procedure was performed in all flaps. The primary and microdissected thinning procedure was performed for 35 single flaps and 7 chimeric flaps, including 14 flaps for the fingers (29%), 4 flaps for the palm (8%), 12 flaps for the hand dorsum (24%), and 19 flaps for combined areas (39%).ResultsThe mean flap thickness was 18.6 (11–30) mm before defatting and 6.0 (3–12) mm after defatting, an approximately 65% reduction. The retained fascia island around the perforator was ≤ 1 cm in 73.5% of cases, 2–3 cm in 18.4%, and the remaining 8.1% had a fascia size ≥ 4 cm. The incidence of a well-survive flap was 93.9%. Three cases had partial to total necrosis. None of the patients required a secondary defatting procedure.ConclusionEvery case has a perforator pattern after running through the fascia, which allows surgeons to choose the appropriate thinning method. Perforators that run parallel to the superficial fascia are not good candidates for thinning. Instead, the thinning process should be performed with more perpendicular perforators.Level of evidence: Level IV, therapeutic study