An Interdigital Microwave Sensor Based on Differential Structure for Dielectric Constant Characteristics Measurement.

In this work, a microwave resonator sensor with a unique configuration consisting of three resonators and two feedlines is proposed. This novel design aims to improve the performance and functionality of microwave resonator sensors for various applications. The frequency response of the sensor to materials with different dielectric constants is simulated. The results show that the most sensitive region of the sensor is located on the first interdigital structure, and placing the materials in other regions would enhance the linear correlation of its frequency response. The sensor also exhibits the ability to distinguish whether the same material has defects and the ability to qualitatively detect subtle changes in dielectric constant. Finally, the proposed sensor is fabricated and measured under the condition consistent with the simulation environment. The measured results are basically consistent with the simulation results, which confirms the potential of this sensor in detecting dielectric constants and resolving materials with defects, and the response of the sensor to the materials under test demonstrates its potential in measuring different thicknesses and loss tangents.

Donor Finger Morbidity in Cross-Finger Flap: A Systematic Review and Meta-Analysis.

Background The morbidity of donor finger in a cross-finger flap has not received as much importance as the outcomes of the flap itself. The sensory, functional, and aesthetic morbidity of donor fingers, reported by various authors, are often contradictory to each other. In this study, objective parameters for the sensory recovery, stiffness, cold intolerance, cosmetic outcome, and other complications in the donor fingers, reported in the previous studies, are systematically evaluated. Methods This systematic review is reported using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) protocol and was registered with the International prospective register of systematic reviews (PROSPERO registration no. CRD42020213721). Literature search was done using "cross-finger," "heterodigital," "donor finger," and "transdigital" words. Data regarding demography, patients' number and age, follow-up duration and outcomes of donor finger, including 2-point discrimination, range of motion (ROM), cold intolerance, questionnaires, etc. were extracted from included studies. Meta-analysis was performed using MetaXL and risk of bias was evaluated using Cochrane risk of bias tool. Results Out of the total 16 included studies, 279 patients were objectively evaluated for donor finger morbidity. Middle finger was most frequently used as donor. Static two-point discrimination seemed to be impaired in donor finger in comparison to contralateral finger. Meta-analysis of ROM suggested that statistically there is no significant difference in ROM of interphalangeal joints in donor and control fingers (pooled weighted mean difference: -12.10; 95% confidence interval: -28.59, 4.39; I2 = 81%, n = 6 studies). One-third of donor fingers had cold intolerance. Conclusion There is no significant effect on ROM of donor finger. However, the impairment that seems to be in sensory recovery and aesthetic outcomes needs to be further evaluated objectively.

Cross-finger Flap to the Thumb: Quest for an Alternate Donor.

Background Distal thumb injuries are managed by multiple local and regional flaps. The cross-finger flap (CFF) is one versatile flap used to cover such defects. The donor finger to the thumb is classically described to be the index finger (IF). However, with the index finger being the second most important finger, it causes further debilitation of the already injured hand. Our aim was to find an alternate donor finger to spare the index finger. Methods and Materials A prospective observational study was conducted on 10 patients with distal thumb injuries who were admitted between November 2018 and July 2019. Ring finger (RF) was used as donor for CFF in all the cases. The subjects were assessed for first web space angle, Kapandji score, total range of movement (TRM) of long fingers, and global hand function using Michigan hand outcome questionnaire (MHQ) after flap division. Results There was no first web contracture and TRM of IF remained unaffected. However, TRM of RF was significantly reduced. But this being a relatively unimportant finger, there was no significant reduction in global hand function, as evaluated by the MHQ score. Conclusion The ring finger is a good alternative for index finger as donor for CFF to the thumb, because it provides adequate tissue along with comfortable positioning and easy maintenance of local hygiene. Moreover, it preserves global hand function by sparing the IF.

Comparison of Homodigital Dorsolateral Flap and Cross-Finger Flap for the Reconstruction of Pulp Defects.

PURPOSE: The homodigital dorsolateral flap (HDF) was described to treat various types of pulp and fingertip defects. The aim of this study was to analyze the intermediate-term function after fingertip reconstruction with HDF and compare these results with the cross-finger flap. METHODS: We analyzed a retrospective cohort of 25 patients. The HDF group consisted of 16 patients (18 fingertip defects) with a mean age of 44 years (range, 16-63 y). The cross-finger flap group consisted of 9 patients (10 fingertip defects) with a mean age of 33 years (range, 16-47 y). The average follow-up time was 12 months (range, 6-36 mo). RESULTS: Patients with homodigital reconstruction demonstrated better sensibility in terms of mean static 2-point discrimination. Two-point discrimination was also better when the flap was advanced compared with when the flap was rotated. Mean distal interphalangeal joint range of motion for the HDF group was significantly better compared with the cross-finger flap group. Proximal interphalangeal joint range of motion was significantly better in the HDF group. CONCLUSIONS: The HDF for reconstruction of pulp defects is a reliable option for 1-stage reconstruction. Related complications are minimal, and the intermediate-term functional results are better compared with cross-finger flaps. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The Reverse Cross Finger Flap.

The reverse cross finger flap is usually performed on patients with deep dorsal digital skin, nailbed, and extensor tendon injuries that cannot be repaired and grafted. These patients will require additional dorsal digital flaps from the adjacent fingers.

Avulsion amputation of the ring finger managed by double cross finger flap: 25 years follow-up.

Avulsion amputation of the fingers are rare. Current trend is to replant the avulsed tissue in spite of a high rate of failure. There are situations where replantation is not possible. Various salvage procedures have been mentioned. The author is presenting a 25 year follow up of a double cross finger flap done in 1987. A similar procedure has been reported by other authors but with a short term follow up.

Comparing clinical and aesthetic outcomes of cross-finger and homodigital reverse digital artery island flap for fingertip injuries: A single-center retrospective cohort study.

BACKGROUND: Reverse homodigital artery island flap (RHDI) has been reported to have some postoperative complications. Cross-finger reverse digital artery island flap (CRDI), which is harvested from an adjacent intact finger, has been used to decrease these complications. This study aimed to provide a review of the CRDI procedure and compare the clinical outcomes of CRDI with those of RHDI. METHODS: RHDI has been performed for fingertip amputations with deficit of 1.5-2.5 cm before 2018, and CRDI has been performed since 2018. We assessed the functional and aesthetic outcomes, including finger length, nail deformity, finger motion, and Hand20 scores at the final follow-up. RESULTS: We identified 22 patients who underwent RHDI and 10 patients who underwent CRDI. The mean follow-up period was 10.3 ± 5.3 months. The median time required for wound healing were 47.0 days (IQR: 34.3-55.8 days) and 34.5 days (IQR: 29.3-44.3 days) in RHDI and CRDI, respectively. The hook nail deformity occurred significantly more frequently in RHDI compared to that in CRDI (40.9% vs. 0.0%, p = 0.03). Flexion contracture of the proximal interphalangeal joint greater than 15º was found to be significantly more in RHDI than in CRDI (36.4% vs. 0.0%, p = 0.04). The median postoperative total active motion of the donor site in CRDI was 278º (IQR: 260-280º). The median postoperative Hand20 scores were similar between the two groups. CONCLUSION: CRDI was associated with superior clinical outcomes in terms of lower rates of postoperative flexion contracture and hook nail deformity, potentially making it a better option compared to RHDI.

[Effectiveness of dorsal perforator flap of cross-finger proper digital artery in treatment of high-pressure injection injuries of the finger].

Objective: To investigate the effectiveness of dorsal perforator flap of cross-finger proper digital artery in the treatment of finger soft tissue defect caused by high-pressure injection injury. Methods: Between July 2011 and June 2020, 14 cases of finger soft tissue defect caused by high-pressure injection injury were repaired with dorsal perforator flap of cross-finger proper digital artery. All patients were male, with a mean age of 36 years (range, 22-56 years). The defects were located on the index finger in 8 cases, middle finger in 4 cases, and ring finger in 2 cases. The causes of injury include 8 cases of emulsion paint injection, 4 cases of oil paint injection, and 2 cases of cement injection. The time from injury to debridement was 2-8 hours, with a mean time of 4.5 hours. The soft tissue defects sized from 4.0 cm×1.2 cm to 6.0 cm×2.0 cm. The flaps sized from 4.5 cm×1.5 cm to 6.5 cm×2.5 cm. The donor site of the flap was repaired with skin graft. The pedicle was cut off at 3 weeks after operation, and followed by functional exercise. Results: All flaps and skin grafts at donor sites survived, and the wounds healed by first intention. Twelve patients were followed-up 16-38 months (mean, 22.6 months). The texture and appearance of all flaps were satisfactory. The color and texture of the flaps were similar to those of the surrounding tissues. The two-point discrimination of the flap was 10-12 mm, with a mean of 11.5 mm. There were different degrees of cold intolerance at the end of the affected fingers. At last follow-up, the finger function was evaluated according to the Upper Extremity Functional Evaluation Standard set up by Hand Surgery Branch of Chinese Medical Association, 3 cases were excellent, 8 cases were good, and 1 case was poor. Conclusion: The dorsal perforator flap of cross-finger proper digital artery can effectively repair finger soft tissue defect caused by high-pressure injection injury. The operation was simple, and the appearance and function of the finger recover well.

Multi-finger receptive field properties in primary somatosensory cortex: A revised account of the spatiotemporal integration functions of area 3b.

The leading view in the somatosensory system indicates that area 3b serves as a cortical relay site that primarily encodes (cutaneous) tactile features limited to individual digits. Our recent work argues against this model by showing that area 3b cells can integrate both cutaneous and proprioceptive information from the hand. Here, we further test the validity of this model by studying multi-digit (MD) integration properties in area 3b. In contrast to the prevailing view, we show that most cells in area 3b have a receptive field (RF) that extends to multiple digits, with the size of the RF (i.e., the number of responsive digits) increasing across time. Further, we show that MD cells' orientation angle preference is highly correlated across digits. Taken together, these data show that area 3b plays a larger role in generating neural representations of tactile objects, as opposed to just being a "feature detector" relay site.

Distally based cross-finger flaps for amputation stumps in avulsion amputations.

BACKGROUND: Though advances in microsurgery have resulted in better survival rates of replants, replanting crushed and avulsed digits are difficult. If replantation is not possible these digits need local tissue cover to retain length. PATIENTS AND METHODS: Twenty seven patients underwent distally based cross finger flaps for coverage of exposed vital structures over the amputation stumps. RESULTS: All the flaps survived well. They provide good quality thin pliable tissue over the fingertips and help in achieving near normal range of movements in injured digits. CONCLUSION: Distally based cross finger flap gives tissues of right dimensions, at the most desired site, making reconstruction of these difficult problems quiet easy.

Comparison of Clinical Outcomes of Heterodigital Neurovascular Island Flap, Reverse Homodigital Neurovascular Island Flap, and Cross-Finger Flap Used for Fingertip Reconstruction.

Objective: The fundamentals of fingertip defect reconstructions should be mainly to restore the sensation with contour and identical pulp volume, and texture. To achieve these, various flap techniques were described in which those had their own advantages and disadvantages to restore the fingertip injuries. This study aimed to compare clinical outcomes of three different local flap procedures widely used for the reconstruction of fingertip defects: heterodigital neurovascular island (HeNI) flap, reverse homodigital neurovascular island (rHoNI) flap, and cross-finger (CF) flap. Methods: Between 2014 and 2019, statistical analysis of 58 patients undergoing reconstruction of fingertip defects of 2-5 digits by HeNI flap (n = 16), rHoNI flap (n = 17), or CF flap (n = 25), was performed retrospectively. All cases were reviewed regarding age, gender, etiology of trauma, duration of follow-up, the extent of the injury with the classification system PNB, Quick Disability of Arm, Shoulder, and Hand score (Q-DASH), cold intolerance symptom severity score (CISS), static 2-point discrimination test, ROM value of phalangeal joints and time to return to work. Results: The mean age of all patients was 36.9 years with a male-to-female ratio of 5.4:1 and a mean follow-up of 26.72 months. The most common cause was work-related (n = 41). The mean of DASH score, CISS score, static 2-point discrimination, time to return to work, and ROM value of DIP joint did not significantly differ between the study groups. The mean ROM values of PIP and MCP joints of patients for CF flaps applied were significantly lower than HeNI flaps. Conclusion: The use of HeNI flap for fingertip reconstruction is a reliable one-stage option in terms of improved ROM of finger joints.

A Systematic Review of the Sensory Outcomes of a Standard Cross-Finger Flap Reconstruction for Fingertip Defects.

Background: The standard (dorsal) cross-finger flap (CFF) is one of the common flaps used for fingertip reconstruction. There is little consensus regarding the sensory outcomes associated with this flap. In this systematic review, we evaluated objective sensory outcome parameters of patients who underwent CFF reconstruction. Methods: This systematic review is reported using the PRISMA protocol and was registered with the International Prospective Register of Systematic Reviews. Literature search was done using the terms 'cross-finger flap', 'heterodigital', 'finger-tip' and 'transdigital'. Data regarding the number of patients, follow-up duration and sensory outcomes, including 2-point discrimination (2-PD) were extracted from included studies. The analysis was performed using Microsoft Excel with MetaXL add-in software. Certainty assessment and summary of findings table was created using GRADEpro GDT. Results: This review includes 14 studies with 301 patients. We found a statistically significant difference in static 2-PD of recipient and control fingers (pooled weighted mean difference [WMD]: 1.66; 95%CI: 0.03, 3.29; p = 0.00; I2=92%, n = 7 studies). Conclusions: Dorsal CFF reconstruction for fingertip defect does not provide adequate sensory recovery. Level of Evidence: Level III (Therapeutic).

A Prospective Trial Comparing Outcomes at 11 Months of a Standard Cross-Finger Flap versus a Laterally Based Thenar Flap for Fingertip Reconstruction.

Background: The standard cross-finger flap (CFF) and laterally based thenar flap (LTF) are the time-tested modalities of fingertip reconstruction. We were unable to find any studies that have compared these two flaps for fingertip reconstruction. The aim of this study is compare the outcomes of these two flaps at 11 months after fingertip reconstruction. Methods: This is a prospective study of 40 patients with fingertip amputation who underwent reconstruction with either a standard CFF or an LTF. Data with regards to the patient, the injury, treatment and complications were recorded. Patients were followed up weekly for the first 6 weeks and at 3, 6, 9 and 12 months thereafter. Outcome measures assessed at final follow-up included passive range of motion, two-point discrimination, cold intolerance, patient aesthetic satisfaction with the flap, assessment of donor scar and psychosocial benefit. Results: Fingertip reconstruction was done with 23 CFFs and 17 thenar flaps. Partial necrosis was noted in three thenar flaps. The mean follow-up period was 11 months. The sensory recovery and aesthetic satisfaction with the flap were greater in thenar flap group. There were no differences between the two flaps in the other outcome measures. Conclusions: Sensory recovery and aesthetic outcomes were better in thenar flaps compared to a CFF. However, thenar flap were associated with a greater incidence of partial flap loss. Level of Evidence: Level III (Therapeutic).

The Clinical Effect of Digital Dorsal Fascial Island Flap Combined With Crossfinger Flap for Repairing Distal Degloving Injury and Sensory Reconstruction.

BACKGROUND: To explore the clinical effect of digital dorsal fascial island flap combined with crossfinger flap to repair distal degloving injury and sensory reconstruction. METHODS: A total of 19 patients with distal fingertip degloving injuries treated with digital dorsal fascial island flap combined with crossfinger flap in our hospital from April 2018 to August 2020 were retrospectively included. Semmes-Weinstein (SW) monofilament and static two-point discrimination (S-2PD) tests, active range-of-motion (ROM) of the fingers, cold intolerance, visual analog scale (VAS) score patient complications, and patient satisfaction were evaluated. RESULTS: Five cases with post-operative flap blisters were treated at the time of dressing changes until successful scab formation. Three cases with post-operative arterial crisis of finger arterial dorsal branch vessel were relieved after suture removal and tension reduction. All other skin flaps and skin grafts survived. Nineteen patients received follow-up between 3 and 26 months (average 14.6 months). The active ROM of metacarpophalangeal (MCP) and interphalangeal (IP) joints of the injured fingers were satisfactory. CONCLUSION: The digital dorsal fascial island flap combined with the crossfinger flap for repairing the distal degloving injury of the distal segment of the finger is a good surgical method, which is simple and easy to operate, can repair a large area of soft tissue defect, and obtain a satisfactory effect.

Mangled finger salvage using cross-finger revascularization.

BACKGROUND: Mangled finger with impaired arteria digitalis communis remains to be a challenge for replantation surgery due to the limited amount of tissue to work with. METHODS: Out of 554 hands with total finger amputations treated by replantation of finger/fingers from July 2012 to June 2018, there were 7 cases of damaged arteria digitalis communis, all of which were replanted by anastomosing distal adjacent radial/ulnar digital artery to distal end of ulnar/radial digital artery of amputation finger, and 2 veins were anastomosed for each finger. A skin pedicle was made by suturing both dorsal and palmar skin of adjacent fingers, and detachment was performed 4 weeks postoperatively. RESULTS: The survival rate was 100%. Mean total active motion was 191.4° (ranging from 170 to 220°). Mean 2-point discrimination was 8 mm static (ranging from 6 to 11 mm), and mean grip strength was 35.3 kg (range, 29 to 40 kg). CONCLUSIONS: Based on our experience, cross-finger revascularization is an effective and safe alternative for mangled finger salvage when arteria digitalis communis is damaged, and good functional prognosis can be expected.

VY Advancement, Thenar Flap, and Cross-finger Flaps.

The VY advancement, thenar flaps, and cross-finger flaps are workhorse flaps used in reconstruction of fingertip defects. They are reliable and simple to raise without need for microvascular dissection. In addition, they usually provide good results in terms of sensibility and range of motion. This article reviews the history, anatomy, and surgical technique of these flaps with a focus on aesthetic refinements with illustrative cases.

Spare-part fillet cross-finger flaps: A series of two cases.

INTRODUCTION: The concept of 'spare-part' flaps in hand reconstruction is most commonly applied using finger fillet flaps to cover dorsal or volar hand defects. In this paper, we introduce the concept of utilization of spare-part finger fillet flaps in a cross-finger fashion. CASE REPORTS: The technique is demonstrated in two case reports. In both cases, there was one finger that was severely crushed requiring amputation. The bones from that finger were removed and the fillet finger flap was utilized to reconstruct a complex defect in an adjacent digit. Immediate post-operative physiotherapy was employed and flap division was done 17-18 days later. Both patients were satisfied with the outcome and returned back to work as manual workers. DISCUSSION: Differences between previous techniques / types of cross-finger flaps and the current spare-part fillet cross-finger flap technique are discussed. CONCLUSION: We introduce the concept of utilization of spare-part finger fillet flaps in a cross-finger fashion.

Reverse digital artery cross-finger flap for reconstruction of failed finger replantation.

PURPOSE: This study aimed to describe the reverse digital artery cross-finger flap (RDAC flap) in the treatment of failed finger replantation. METHODS: This study retrospectively reviewed the records of patients who underwent modified RDAC flap reconstructions for failed finger replantation and assessed their outcomes. Of the patients who underwent soft tissue reconstructions for finger injuries between March 2011 and February 2015, we enrolled 11 patients in whom RDAC flap reconstruction procedures were performed to treat the failed replantations. RESULTS: The flaps survived in all cases, with a mean static, two-point discrimination value of 5.3 mm (range, 4-7 mm) in the healed flaps. The sizes of the flaps ranged from 2 × 1 cm2 to 2.3 × 1.5 cm2. CONCLUSION: The RDAC flap was introduced by Lai et al., and it is a mixed form with the advantages of both cross-finger flap and heterodigital island flap. Our results suggest that it could provide reliable coverage of the sensate soft tissue of fingers with failed replantation.

Treatment of fingertip avulsion injuries using two periposition pedicled flaps.

We described a treatment of fingertip avulsion injury by two periposition pedicled flaps, the reversed pedicle island flap of dorsal branch of proper digital artery and the cross-finger flap. From February 2009 to January 2017, 22 patients (22 fingers) with fingertip avulsion injury were treated with two periposition pedicled flaps, 14 male and 8 female, aged from 17 to 47 years (mean 32 ± 9 years). All of the patients were followed up more than 6 months after operations (mean 9.6 ± 2.6 months). All flaps survived completely. Compared with the traditional abdominal flaps, two periposition pedicled flaps had less pedicle division time. At last follow-up, the 2PD of the palmar part of the flaps, the TAM of the injured finger and the MHQ summary score of the two periposition pedicled flaps were much better than the traditional abdominal flaps. The reconstruction using two periposition pedicled flaps is a versatile treatment with better functions, less morbidity and better aesthetics. Level of evidence: Therapeutic, level III.