Effect of tibial cortex transverse transport in patients with recalcitrant diabetic foot ulcers: A prospective multicenter cohort study

Background

Management of recalcitrant diabetic foot ulcer (DFU) remains difficult. Distraction osteogenesis mediates new bone formation and angiogenesis in the bone itself and the surrounding tissues. Recently it was reported that tibial cortex transverse transport (TTT) was associated with neovascularization and increased perfusion at the foot in patients with recalcitrant DFUs and facilitated healing and limb salvage. However, the findings were from several single-center studies with relatively small populations, which need to be confirmed in multicenter cohort studies with relatively large populations. Furthermore, the effect of this technique on patient's health-related quality of life is still unclear.

Methods

We treated patients with recalcitrant (University of Texas wound grading system 2-C to 3-D and not responding to prior routine conservative and surgical treatments for at least 8 weeks) DFUs from seven centers using TTT (a 5 ​cm ​× ​1.5 ​cm corticotomy followed by 4 weeks of medial and lateral distraction) between July 2016 and June 2019. We analyzed ulcer healing, major amputation, recurrence, health-related quality of life (physical and mental component summary scores), and complications in the 2-year follow-up. Foot arterial and perfusion changes were evaluated using computed tomography angiography and perfusion imaging 12 weeks postoperatively.

Results

A total of 1175 patients were enrolled. Patients who died (85, 7.2%) or lost to follow-up (18, 1.7%) were excluded, leaving 1072 patients for evaluation. Most of the patients were male (752, 70.1%) and with a mean age of 60.4 ​± ​9.1 years. The mean ulcer size was 41.0 ​± ​8.5 ​cm² and 187 (16.6%) ulcers extended above the ankle. During the follow-up, 1019 (94.9%) patients healed in a mean time of 12.4 ​± ​5.6 weeks, 53 (4.9%) had major amputations, and 33 (3.1%) experienced recurrences. Compared to preoperatively, the patients had higher physical (26.2 ​± ​8.3 versus 41.3 ​± ​10.6, p ​= ​0.008) and mental (33.6 ​± ​10.7 versus 45.4 ​± ​11.3, p ​= ​0.031) component summary scores at the 2-year follow-up. Closed tibial fracture at the corticotomy site was found in 8 (0.7%) patients and was treated using external fixation and healed uneventfully. There were 23 (2.1%) patients who had pin site infections and were treated successfully with dressing changes. Compared to preoperatively, the patients had more small arteries and higher foot blood flow (8.1 ​± ​2.2 versus 28.3 ​± ​3.9 ml/100 ​g/min, p ​= ​0.003) and volume (1.5 ​± ​0.3 versus 2.7 ​± ​0.4 ml/100 ​g, p ​= ​0.037) 12 weeks postoperatively.

Conclusion

TTT promotes healing, limb salvage, and health-related quality of life in patients with recalcitrant DFUs as demonstrated in this multicenter cohort study. The surgical procedure was simple and straightforward and the complications were few and minor. The effect of this technique was associated with neovascularization and improved perfusion at the foot mediated by the cortex distraction. The findings are required to confirm in randomized controlled trials.The Translational Potential of this Article: TTT can be used as an effective treatment in patients with recalcitrant DFUs. The mechanism is associated with neovascularization and consequently increased perfusion in the foot after operation.

Efficacy and safety of unilateral tibial cortex transverse transport on bilateral diabetic foot ulcers: A propensity score matching study

Background

Tibial Cortex Transverse Transport (TTT) has been demonstrated to be an effective treatment for unilateral diabetic foot ulcers (UDFUs). However, this retrospective study was designed to compare the efficacy and safety of unilateral TTT on bilateral diabetic foot ulcers (BDFUs).

Methods

This retrospective study included a review of patients with TTT treated from January 2017 to August 2019, Propensity Score Matching (PSM) was performed to compare patients with BDFUs to those with UDFUs. Ulcer healing, recurrence, and major amputation rates were evaluated at 1-year follow-up. Changes in foot vessels were assessed in the BDFUs group using computed tomography angiography (CTA).

Results

A total of 140 patients with DFUs (106 UDFUs and 34 BDFUs) were included in the study. UDFUs and BDFUs were matched in a 1:1 ratio (34 in each group) using PSM. No significant difference was observed at 1-year-follow-up [91.2% (31/34) vs. 76.5% (26/34), OR 0.315 (95% CI 0.08 to 1.31), P ​= ​0.10] and 6-month-follow-up [70.6% (24/34) vs. 50.0% (17/34), OR 0.85 (95% CI 0.15 to 1.13), P ​= ​0.08] in two groups. Significant differences in rates of major amputation and recurrence between the groups (P ​> ​0.05) were not observed. The BDFUs group appeared more angiogenesis of the foot by CTA after 8 weeks of operation.

Conclusion

Results of this study suggest that severe BDFUs can be effectively treated by unilateral TTT. TTT is easy to operate and effective, which may be a good alternative for treating severe BDFUs.

The translational potential of this article

In previous retrospective clinical studies, TTT has demonstrated promising clinical outcomes in the management of diabetic foot ulcers. In this current study, we aim to investigate the potential use of TTT in treating distant tissue defects by evaluating the limited availability and safety of TTT for the management of bilateral diabetic foot. While additional basic and clinical research is necessary to fully elucidate the underlying mechanisms, our study offers insight into the potential therapeutic use of TTT for this condition.

Learning curve of tibial cortex transverse transport: a cumulative sum analysis

OBJECTIVE

This study aimed to describe the learning curve of surgeons performing tibial cortex transverse transport (TTT) and explore its safety and effectiveness during the initial stages of surgeon's learning.

METHODS

The clinical data of patients with diabetic foot ulcers classified as Wagner grade ≥ 2, who underwent TTT at our hospital from January 2020 to July 2021, were included in this retrospective analysis. The same physician performed all procedures. Patients were numbered according to the chronological order of their surgery dates. The cumulative sum and piecewise linear regression were used to evaluate the surgeon's learning curve, identify the cut-off point, and divide the patients into learning and mastery groups. A minimum follow-up period of 3 months was ensured for all patients. Baseline data, perioperative parameters, complications, and efficacy evaluation indicators were recorded and compared between the two groups.

RESULTS

Sixty patients were included in this study based on the inclusion and exclusion criteria. After completing 20 TTT surgeries, the surgeon reached the cut-off point of the learning curve. Compared to the learning group, the mastery group demonstrated a significant reduction in the average duration of the surgical procedure (34.88 min vs. 54.20 min, P < 0.05) along with a notable decrease in intraoperative fluoroscopy (9.75 times vs. 16.9 times, P < 0.05) frequency, while no significant difference was found regarding intraoperative blood loss (P = 0.318). Of the patients, seven (11.7%) experienced complications, with three (15%) and four cases (10%) occurring during the learning phase and the mastery phase, respectively. The postoperative ulcer area was significantly reduced, and the overall healing rate was 94.8%. Significant improvements were observed in postoperative VAS, ABI, and WIFI classification (P < 0.05). There were no significant differences in the occurrence of complications or efficacy indicators between the learning and mastery groups (P > 0.05).

CONCLUSION

Surgeons can master TTT after completing approximately 20 procedures. TTT is easy, secure, and highly efficient for treating foot ulcers. Furthermore, TTT's application by surgeons can achieve almost consistent clinical outcomes in the initial implementation stages, comparable to the mastery phase.

Tibial cortex transverse transport regulates Orai1/STIM1-mediated NO release and improve the migration and proliferation of vessels via increasing osteopontin expression

Background

Diabetic foot is a major complication of diabetes. The bone transverse transport method could be applied in clinics for treatment, which could improve the metabolism of the tissues via lasting distraction forces. However, the process' specific regulating mechanism is still unknown.

Methods

Based on the notion that the healing of bones involves the recruitment of calcium ions, in this study, we established the model of tibial cortex transverse transport (TTT) on rats and then used tissue immunologic detection, such as the double fluorescent staining to explore the expression of the calcium channels' calcium release-activated calcium modulator 1 (Orai1)/stromal interaction molecule 1 (STIM1), which belong to the store-operated calcium entry (SOCE) signaling pathways on the tissues around the bone transport area. By using the laser capture microdissection (LCM) tool, we acquired samples of tissues around the bone and endeavored to identify pivotal protein molecules. Subsequently, we validated the functions of key protein molecules through in vitro and in vivo experiments.

Results

After protein profile analysis, we found the differentially expressed key protein osteopontin (OPN). The in vitro experiments verified that, being stimulated by OPN, the migration, proliferation, and angiogenesis of human umbilical vein endothelial cells (HUVEC) were observed to be enhanced. The activation of Orai1/STIM1 might increase the activity of endothelial nitric oxide synthase (eNOS) and its effect on releasing nitric oxide (NO). Subsequently, the migration and proliferation of the HUVECs are improved, which ultimately accelerates wound healing. These signaling pathway was also observed in the OPN-stimulated healing process of the skin wound surface of diabetic mice.

Conclusion

This study identifies the molecular biological mechanism of OPN-benefited the migration and proliferation of the HUVECs and provides ideas for searching for new therapeutic targets for drugs that repair diabetes-induced wounds to replace invasive treatment methods.

The translational potential of this article

The OPN is highly expressed in the tissues surrounding the TTT bone transfer area, which may possibly stimulate the activation of eNOS to increase NO release through the SOCE pathway mediated by Orai1/STIM1. This mechanism may play a significant role in the angiogenesis of diabetic foot's wounds promoted by TTT, providing new therapeutic strategies for the non-surgical treatment for this disease.

Efficacy of tibial cortex transverse transport in treating diabetic foot ulcer and its effect on serum omentin-1 and irisin levels

OBJECTIVE

Diabetic foot ulcer (DFU) is a common and debilitating complication of diabetes that is associated with an increased risk of lower-limb amputation and a reduced life expectancy. Tibial cortex transverse transport (TTT) has become a newly alternative surgical method to facilitate ulcer healing and prevent lower limb amputation. Herein, we investigated the efficacy of TTT in treating DFU and changes of serum omentin-1 and irisin levels.

METHODS

This study prospectively recruited 52 consecutive patients with DFU who were treated with TTT. The follow-up was performed weekly during the first 12 weeks postoperatively and every 3 months until 1 year after TTT. The serum levels of vascular endothelial growth factor (VEGF), omentin-1, and irisin in DFU patients undergoing TTT were determined by ELISA methods on the preoperative 1st day, postoperative 2nd week and 4th week.

RESULTS

The wound healing rate was 92.3% (48/52) at the 1-year follow-up. The visual analog scale (VAS) pain scores of patients showed a significant reduction at the 4th week after TTT (p < 0.001). The dorsal foot skin temperature, ankle brachial index, and dorsal foot blood flow of patients were significantly increased at the 4th week after TTT (p < 0.001). Results of ELISA methods showed the serum levels of VEGF, omentin-1, and irisin on the 2nd week and 4th week after TTT were notably elevated compared to the levels determined on the preoperative 1st day (p < 0.001). The serum levels of VEGF, omentin-1, and irisin on the 4th week after TTT were also significantly higher than the levels determined on the 2nd week after TTT (p < 0.001).

CONCLUSION

TTT could promote the wound healing and reduce the risk of lower limb amputation, demonstrating promising clinical benefits in the treatment of DFU. Increased expressions of serum proangiogenic factors including VEGF, omentin-1, and irisin were noted in the early stage after TTT, which may provide a new mechanism of TTT promoting wound heal.