Objective To investigate the feasibility and effectiveness of ulnar cortex transverse transport technique in treating upper extremity thromboangiitis obliterans (TAO). MethodsA retrospective analysis was conducted on the clinical data of 7 male patients with upper extremity TAO who were admitted and met the inclusion criteria between January 2019 and July 2022. The patients ranged in age from 32 to 50 years, with a mean age of 40.1 years. The disease duration ranged from 6 to 24 months, averaging 13.6 months. The smoking history ranged from 8 to 31 years, with a mean of 18.4 years. All patients presented with finger ulcers or gangrene, including 1 case affecting the thumb and index finger, 1 case affecting the index and middle fingers, 1 case affecting the middle and ring fingers, 1 case affecting only the ring finger, and 3 cases affecting the ring and little fingers. The preoperative visual analogue scale (VAS) score was 9.1±0.7. All patients underwent treatment with the ulnar cortext transverse transport technique. The wound healing time and the disappearance time of rest pain were recorded. The VAS score was used to assess the degree of hand pain before and after operation. Serum interleukin 6 (IL-6) levels were measured before operation and at 1 month after operation. Computed tomography angiography (CTA) of the affected limb was performed before operation and at 3 months after operation to evaluate changes in blood vessels. The clinical outcomes were evaluated at 1 year after operation based on the Patwa and Krishnan grading system. ResultsAll 7 patients were followed up 12-17 months, with an average of 13.7 months. All patients experienced successful healing of ulcers, with wound healing time ranging from 14 to 21 days, averaging 17.3 days. During the follow-up, no complication occurred, and there was no recurrence of ulcers. The disappearance time of rest pain ranged from 8 to 15 days, averaging 12.1 days. The pre- and post-operative (1-month) serum IL-6 levels were (25.1±5.9) pg/mL and (11.9±2.9) pg/mL, respectively, with a significant difference (t=5.363, P=0.002). CTA examination at 3 months after operation revealed partial revascularization of upper extremity arteries and establishment of collateral circulation, showing significant improvement compared to preoperative status. The VAS scores at 1, 7, 28 days, and 6 months postoperatively were 6.4±0.8, 3.7±0.8, 0.6±0.8, and 0.1±0.4, respectively, all of which significantly improved compared to preoperative scores (P<0.05). Furthermore, the VAS scores gradually decreased over time, with significant differences observed between postoperative time points (P<0.05). At 1 year after operation, the effectiveness of all 7 patients were evaluated as excellent based on the Patwa and Krishnan grading system. ConclusionThe ulnar cortex transverse transport technique can improve blood circulation in the upper limb of patients with TAO, reconstruct microcirculation, inhibit inflammation, promote ulcer healing, and alleviate limb pain.