Recent Advances in Immediate Toe-to-Hand Transfer

Free neurovascular toe-(joint)-transfers compared to alternative reconstructive procedures for amputation injuries of two and tripartite fingers with substance loss

BACKGROUND

Complex injuries of the hand frequently result in loss of essential functional features. Common reconstructive procedures for soft tissue defects of the thumb or phalanges are locoregional flaps like Moberg-, Foucher-, Cross-Finger- or Littler flaps. Microneurovascular toe (joint-) transfers complete the arsenal of operative reconstructive procedures and allow for most detailed reconstructions. Our experiences with free toe transplants are reported and diversely discussed regarding contending procedures.

METHODS

From 2010 until 2019 14 patients who received emergency or elective partial or complete toe transfers were compared with a control group (n = 12) treated with contending reconstructive procedures. Aim of the reconstructions was to cover the defect with well-vascularized, sensate tissue, while preserving length and range of motion in a reliable manner.

RESULTS

The Kapandji score showed a significant difference (p- value = 0.04) with a score of 9.8 in comparison to control group (Kapandji index = 8.0).

CONCLUSION

In our heterogenic patient collective free toe transplants have proven to achieve comparable functional results for reconstruction of two and tripartite phalanxes as opposed to common local reconstructive procedures.

Three-Dimensional Computer-Aided Design Modeling and Printing for Accurate Toe-to-Hand Transplantation

PURPOSE

To introduce toe-to-hand transplantation performed with the assistance of both bone and soft tissue modeling using 3-dimensional printing technology.

METHODS

From May 2015 to October 2018, 31 patients (group A, 24 thumbs and 7 fingers) were included. Computed tomography scans were acquired using a spiral computed tomography scanner, and the data were processed with software. Bone, skin, and nail models were created for tailoring the flap taken from the great toe. The impact of foot pathology in terms of pain, disability, and activity restriction was assessed using the Foot Function Index. For comparison, we included 35 patients (group B) who underwent toe-to-hand transplantation without the assistance of 3-dimensional computer-aided modeling.

RESULTS

The mean duration of follow-up of groups A and B was 26 months (range, 24-31 months) and 27 months (range, 24-33 months), respectively. The mean Foot Function Index of groups A and B was 5 (range: 0-15) and 17 (range, 0-39), respectively.

CONCLUSIONS

Three-dimensional computer-aided modeling and printing provide geometric accuracy in toe-to-hand transplantation. It also may reduce the donor foot morbidity by accurate flap designing and harvesting.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

New, Innovative, Three-Dimensional In Vivo Model for High-Level Microsurgical and Supermicrosurgical Training: A Replacement for Animal Models

SUMMARY

Microsurgery and supermicrosurgery are surgical subdomains necessary for a large variety of surgical disciplines. So far, there is no training model for lymphatic surgery or perforator flap surgery, and the most commonly used microsurgical training models are living animals. However, the ethical principles of replacement, refinement, and reduction (the three Rs) of living animals for training purposes were implemented, highlighting the necessity of an animal-sparing microsurgical training model. Formed during embryogenesis, the chick chorioallantoic membrane resembles a highly vascularized, noninnervated membrane within fertilized chicken eggs. The aim of this study was to utilize the chorioallantoic membrane model as an innovative and versatile training model for supermicrosurgery and microsurgery that can reduce the number of animals used for these purposes. The variety of different sized vessels for the implementation of an anastomosis proved the chorioallantoic membrane model as a well-functioning supermicrosurgical and microsurgical training model. The circulatory system is resilient enough to withstand the mechanical stress applied to the tissue, and the patency of the implemented anastomosis can be tested for the verification of the procedures. In summary, the integration of the chorioallantoic membrane model into a surgical training program can benefit its quality by representing a realistic anatomical and physiological model with a high variety of vascular structures. Moreover, the chorioallantoic membrane model satisfies the principles of replacement, refinement, and reduction as an animal-sparing model, indicating the potential of this model as an innovative microsurgical training model for the improvement of surgical skills.

Repair of thumb defect by using the toenail flap: biomechanical analysis of donor foot-a retrospective cohort study

BACKGROUND

The thumb accounts for 50% of the total hand function. This study reports the functional outcomes and complications of people with traumatic thumb amputations who underwent toe-to-thumb reconstruction.

METHODS

From January 2013 to January 2018, 29 patients with second-degree thumb defect underwent thumb reconstruction with distal phalangeal braided toenail flap. The footscan foot pressure gait analysis system was used to measure the index changes of the same foot before and after 1, 3 and 6 months. The contact area, peak pressure, impulse value, contact time of each gait phase, centre of gravity coordinate and foot balance were analysed statistically.

RESULTS

Twenty-nine cases of thumb reconstruction recovered well. After following up for 6-15 months, the appearance of the reconstructed thumb was close to normal, and the sensation was restored to S3⁺. The two-point discrimination was 6-8 mm, and the function of the thumb was good. The function of the donor foot was well restored, and no skin ulceration, pain and claudication were noted during walking. Compared with that before the operation, the biomechanical indices of the donor foot were basically restored to normal 6 months after the operation. Only the stress and impulse values of the third metatarsal head were significantly increased, forming a stress concentration area centred on the third metatarsal head.

CONCLUSIONS

This study confirmed that the toenail flap with distal phalangeal bone restored the second-degree thumb defect without destroying the main functional structure of the sole. The biomechanical indices of the donor foot were basically restored to normal 6 months after the operation. Only the stress concentration area centred on the third metatarsal head, and the pain on the forefoot was induced after the operation. Discomfort, callus formation, metatarsal fasciitis, etc., can lead to fatigue fracture of the third metatarsal bone in severe cases, which requires further follow-up and observation.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT03879941; registered on 10 March 2019, retrospectively.

Combination free foot flaps for digit reconstruction: A retrospective analysis of 37 cases

Combination foot flaps for digit reconstruction was previously introduced by our group as an alternative method for toe-to-hand transfer. The aim of this study was to analyze our experience with the combination foot flaps and to present the surgical refinements that were introduced. A prospective study was conducted including all combination foot flaps performed at our hospital since September 2009. Surgical refinements that were introduced during this study included island flap for repair of toenail donor site and the use of Z-plasty. The median operation duration was 6.7 hours (range 3.5-13 h). Among 74 flaps, partial necrosis occurred in three flaps (4.1%); two palmar flaps (2.7%) were bulky. Among 37 cases of reconstructed digits, contracture of the first web occurred in one case (1.4%). All the patients were able to walk well and did not complain of any pain or cold intolerance. Wound dehiscence of donor site was observed in three patients (8.1%). Toenail deformity occurred in one case (2.7%). The combination foot flap is a reliable option for digit reconstruction with minimal donor site complications.