Massive cortical reorganization is reversible following bilateral transplants of the hands: evidence from the first successful bilateral pediatric hand transplant patient

What is needed to ensure long-term sustainability for the field of vascularized composite allotransplantation?

The field of vascularized composite allotransplantation (VCA) has demonstrated remarkable advances since its inception with some excellent long-term results in a variety of graft types. However, unlike solid organ transplantation, it has yet to become mainstream. We therefore discuss strategies on ensuring long-term sustainability by addressing continued clinical developments of VCA to improve the risk-to-benefit balance, importance of public support, improved policy and financial support, and need for a bridge to the future of transplant surgery. There has been headway on all fronts and collaboration among the VCA centers for centralization of data and incorporation of patient voices will be essential for continued progress.

Hand Therapy Regimen for Functional Recovery Following Combined Face and Bilateral Hand Transplantation

Intensive postoperative rehabilitation therapy is associated with positive functional recovery in hand transplants (HTs). Our goal is to share the hand therapy protocol developed for our patient who underwent a combined face and bilateral HT. The patient is a 23-year-old right-hand-dominant male with a history of third-degree burns to 80% of his body following a motor vehicle accident. A multidisciplinary evaluation established his candidacy for a combined face and bilateral HT, and surgery took place in August 2020. Our individualized hand therapy protocol consisted of 4 phases. The pre-surgery phase focused on planning the orthotics and patient/caregivers' education on the rehabilitation process. The intensive care unit (ICU)/acute care phase involved hand allograft protection and positioning via orthotic fabrication, safe limb handling, and edema/wound management. The inpatient rehabilitation phase aimed to prepare the patient for independent living via neuromuscular and sensory re-education, improvement of upper extremities strength/flexibility, training basic activities of daily living, and providing a home exercise program (HEP). Finally, the outpatient phase aimed to maximize our patient's range of motion and independency in performing his routine activities and HEP. The patient's post-transplant functional outcomes showed a significant improvement compared to the pre-operative baseline. We hope this report sheds light on a comprehensive hand therapy program in HT.

Somatosensory and motor representations following bilateral transplants of the hands: A 6-year longitudinal case report on the first pediatric bilateral hand transplant patient

A vascularized composite tissue allotransplantation (VCA) was performed at the Children's Hospital of Philadelphia (CHOP), on an 8-year-old patient in 2015, six years after bilateral hand and foot amputation. Hand VCA resulted in reafferentation of the medial, ulnar, and radial nerves serving hand somatosensation and motor function. We used magnetoencephalography (MEG) to assess somatosensory cortical plasticity following the post-transplantation recovery of the peripheral sensory nerves of the hands. Our 2-year postoperative MEG showed that somatosensory lip representations, initially observed at "hand areas", reverted to canonical, orthotopic lip locations with recovery of post-transplant hand function. Here, we continue the assessment of motor and somatosensory responses up to 6-years post-transplant. Magnetoencephalographic somatosensory responses were recorded eight times over a six-year period following hand transplantation, using a 275-channel MEG system. Somatosensory tactile stimuli were presented to the right lower lip (all 8 visits) as well as right and left index fingers (visits 3-8) and fifth digits (visits 4-8). In addition, left and right-hand motor responses were also recorded for left index finger and right thumb (visit 8 only).During the acute recovery phase (visits 3 and 4), somatosensory responses of the digits were observed to be significantly larger and more phasic (i.e., smoother) than controls. Subsequent measures showed that digit responses maintain this atypical response profile (evoked-response magnitudes typically exceed 1 picoTesla). Orthotopic somatosensory localization of the lip, D2, and D5 was preserved. Motor beta-band desynchrony was age-typical in localization and response magnitude; however, the motor gamma-band response was significantly larger than that observed in a reference population.These novel findings show that the restoration of somatosensory input of the hands resulted in persistent and atypically large cortical responses to digit stimulation, which remain atypically large at 6 years post-transplant; there is no known perceptual correlate, and no reports of phantom pain. Normal somatosensory organization of the lip, D2, and D5 representation remain stable following post-recovery reorganization of the lip's somatosensory response.

Cortical reintegration after facial allotransplantation

Neural plasticity of the brain or its ability to reorganize following injury has likely coincided with the successful clinical correction of severe deformity by facial transplantation since 2005. In this study, we present the cortical reintegration outcomes following syngeneic hemifacial vascularized composite allograft (VCA) in a small animal model. Specifically, changes in the topographic organization and unit response properties of the rodent whisker-barrel somatosensory system were assessed following hemifacial VCA. Clear differences emerged in the barrel-cortex system when comparing naïve and hemiface transplanted animals. Neurons in the somatosensory cortex of transplanted rats had decreased sensitivity albeit increased directional sensitivity compared with naïve rats and evoked responses in transplanted animals were more temporally dispersed. In addition, receptive fields were often topographically mismatched with the indication that the mismatched topography reorganized within adjacent barrel (same row-arc bias following hemifacial transplant). These results suggest subcortical changes in the thalamus and/or brainstem play a role in hemifacial transplantation cortical plasticity and demonstrate the discrete and robust data that can be derived from this clinically relevant small animal VCA model for use in optimizing postsurgical outcomes.NEW & NOTEWORTHY Robust rodent hemifacial transplant model was used to record functional changes in somatosensory cortex after transplantation. Neurons in the somatosensory cortex of face transplant recipients had decreased sensitivity to stimulation of whiskers with increased directional sensitivity vs. naive rats. Transplant recipient cortical unit response was more dispersed in temporary vs. naive rats. Despite histological similarities to naive cortices, transplant recipient cortices had a mix of topographically appropriate and inappropriate whiskered at barrel cortex relationships.

5-Year Activity and Participation Outcomes of the First Successful Pediatric Bilateral Hand Transplantation: A Case Report

AIMS

Describe the 5-year outcomes of the first successful pediatric bilateral hand transplantation.

METHODS

The child underwent quadrimembral amputation at age two and received bilateral hand allografts at age eight. Rehabilitation included biomechanical, neurorehabilitation, and occupational approaches in acute and outpatient settings. Therapist observed outcomes, patient-reported measures, and parent-reported measures were repeated over a 5-year period.

RESULTS

Observation assessments revealed functional dexterity skills and modified independence to full independence with self-care activities. The parent reported the child had moderate difficulty with upper extremity functioning 25-, 41-, and 48-months post-transplantation, and mild difficulty at 60-months; the child reported no difficulties in this domain at 41 months. Five years post-transplantation the child reported enjoying many age-appropriate activities, and high-quality peer relations were endorsed by both parent and child.

CONCLUSION

The child developed hand movements for daily activities and was completing daily activities with improved efficiency. Health-related quality of life outcomes were favorable.

Addressing common orthopaedic calamities with microsurgical solutions

Reconstructive microsurgery has been an essential aspect of orthopaedic surgery and extremity reconstruction since the introduction of the operating microscope in the mid-20^th century. The reconstructive ladder ranges from simple healing by secondary intention to complex procedures such as free tissue transfer and vascularized composite allotransplantation. As orthopaedic surgery has evolved over the past 60 years, so too have the reconstructive microsurgical skills that are often needed to address common orthopaedic surgery problems. In this article, we will discuss a variety of complex orthopaedic surgery scenarios ranging from trauma to infection to tumor resection as well as the spectrum of microsurgical solutions that can aid in their management.

Complementary Phenomena: Phantom Hand and Phantom Face

After tissue or limb loss, the development of sensation and perception of the lost or deafferent tissue is defined as a phantom phenomenon. We investigated the presence of phantom phenomena in individuals who underwent a full face transplant as well as those who had a hand transplant. Specifically, we investigated sensory perception of the face on the fingers and sensory perception of the fingers on the face in three full face and four hand transplant patients. In all seven individuals, we used a brush to separately stimulate the right and left sides of the face or the palmar and dorsal faces of the hand. We then asked the individuals if they felt a sensation of touch on any other part of their body and, if so, to describe their perceptions. Changes in the regions of the primary sensory cortex representing the hand and face were defined using fMRI obtained via tactile sensory stimulation of the clinical examination areas. Two of the full face transplant patients reported sensory perceptions such as a prominent sensation of touch on their faces during sensory stimulation of their fingers. Three of the hand transplant patients reported sensory perceptions, which we referred to as finger patches, during sensory stimulation of the face area. In fMRI, overlaps were observed in the cortical hand and face representation areas. We consider the phantom hand and phantom face phenomena we observed to be complementary due to the neighborhood of the representations of the hand and face in the somatosensory cortex.

Measuring Functional Outcomes After Bilateral Vascularized Composite Hand Allotransplantation: A Report of 3 Cases

PURPOSE

Currently, numerous assessment tools are available to measure functional outcomes after bilateral hand transplantation. The purpose of this article is to present our experience utilizing quantitative assessment tools for functional evaluation and to describe our results after bilateral hand transplantation.

METHODS

A single surgeon's experience with bilateral hand transplantation from 2011 to 2016 was retrospectively reviewed. Three bilateral hand transplantations were performed in 2 adults and 1 child. A minimum 2-year follow-up evaluation was available. For the adult patients, postoperative outcome measures included patient-reported pain and disability scores, return of sensation, muscle strength, range of motion, and return to work/activities of daily living, the Hand Transplant Scoring System (HTSS), the Sollerman hand function test, and complications. For our pediatric patient, postoperative outcome measures included the Functional Independence Measure for children (WeeFIM) scale, a functional independence measure for children, the 9-Hole Peg Test, the Box and Block test, and complications.

RESULTS

Our 2 adult patients were age 28 and our pediatric patient was age 8 at transplantation. Follow-up ranged from 2 to 7 years. The functional assessments were performed over a period from 11 to 48 months after transplantation. Both adult patients achieved functional independence and the HTSS, Short Form-36 Health Score (SF-36), DASH, and Sollerman tests demonstrated sequential improvement compared with pretransplantation scores assessed with the use of prostheses. Our pediatric patient demonstrated improvement in his Box and Block test score for each hand at sequential visits after transplantation. His 9-Hole Peg Test demonstrated improvement, and his WeeFIM assessment at 20 months indicated a greater level of independence.

CONCLUSIONS

Patient-reported outcomes and the Sollerman test when used in addition to the HTSS appear to reflect functional improvement in adult patients after bilateral hand transplantation. Although children pose a unique challenge with functional assessment, we found the WeeFIM assessment, 9-Hole Peg Test, and the Box and Block test helpful in evaluating functional outcomes in our pediatric patient.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Building a Hand and Upper Extremity Transplantation Program: Lessons Learned From the First 20 Years of Vascularized Composite Allotransplantation

Background: Upper extremity transplantation is a quality-of-life enhancing treatment for select patients with upper extremity loss. This article reviews the preoperative, intraoperative, and postoperative challenges in the upper extremity transplantation process and the lessons learned from the first 2 decades of hand transplantation. Methods: Key components of the author's hand transplantation protocol including patient selection, donor screening, surgical rehearsal, donor procurement, transplantation, immunosuppression, and patient outcome reporting/follow-up are reported to assist other teams who wish to establish a hand transplantation program. Results: There have been many advancements in the first 20 years of hand transplantation including better patient selection criteria, the recent addition of pediatric patients, improved surgical techniques such as the use of virtual surgical planning, and improved immunosuppression protocols. Improvement has also taken place in the tracking and reporting of hand transplant outcomes, but more work is clearly needed to fully define the benefits of transplantation, especially for pediatric patients. Conclusions: Over the past 20 years, significant progress has been made in upper extremity transplantation although a number of challenges remain including how to best document and share outcome measures, optimize immunosuppression, and diagnose/treat rejection. The authors encourage upper extremity transplant programs to report their experience and protocols to advance hand transplantation as standard of care for properly selected individuals.

Virtual Reality Provides an Effective Platform for Functional Evaluations of Closed-Loop Neuromyoelectric Control

Although recent advances in neuroprostheses offer opportunities for improved and intuitive control of advanced motorized and sensorized robotic arms, practical complications associated with such hardware can impede the research necessary for clinical translation. These hurdles potentially can be reduced with virtual reality environments (VREs) with embedded physics engines using virtual models of physical robotic hands. These software suites offer several advantages over physical prototypes, including high repeatability, reduced human error, elimination of many secondary sensory cues, and others. There are limited demonstrations of closed-loop prostheses in the VRE, and it is unclear whether VRE performance translates to the physical world. Here we describe how two trans-radial amputees with neural and intramuscular implants identified objects and performed activities of daily living with closed-loop control of prostheses in the VRE. Our initial evidence further suggests that capabilities with virtual prostheses may be predictors of physical prosthesis performance, demonstrating the utility of VREs for neuroprosthetic research.

Cortical Plasticity After Surgical Tendon Transfer in Tetraplegics

Background: Developmental cortical plasticity with reorganization of cerebral cortex, has been known to occur in young and adult animals after permanent, restricted elimination of afferent (visual or somatosensory) input. In animals, cortical representation of unaffected muscles or sensory areas has been shown to invade the neighboring cortex when this is deprived of its normal sensory input or motor functions. Some studies indicate that similar cortical plasticity may take place in adult humans. Methods: In patients with a high cervical spinal cord injury leaving the patient without any movements of the fingers, we performed fMRI studies of the cortical representation of an elbow flexor muscle before and after a surgical procedure that changed its function to a thumb flexor, thus providing the patient with a useful grip. Results: Preoperatively, the elbow flexion movement was elicited from a cortical area corresponding with the "elbow area" in healthy individuals. Despite the fact that an elbow flexor was used for the post-operative key-grip, this movement in the tetraplegic patients was elicited from a similar brain region as in healthy controls (the "hand area"). This supports our hypothesis that control of that muscle shifts from a brain region typically associated with elbow movement, to one typically associated with wrist movements. Conclusion: The findings presented here show with fMRI that the human cortex is capable of reorganizing itself spatially after a relatively acute change in the periphery.