The distribution of serotonin(5-HT), phenylethanolamine-N-methyltransferase (PNMT), substance P(SP) and leu-enkephalin(L-ENK) immunoreactive neurons in the rostral ventrolateral medulla (RVL) of the cat was studied with the immunohistochemical ABC technique, and the projection of 5-HT, SP and L-ENK positive neurons of the RVL into the thoracic cord was preliminarily investigated by a combined fluorescent retrograde transport and immunofluorescence method. The results indicate that 5-HT, PNMT, SP and L-ENK immunoreactive neurons mentioned above were localized primarily in the caudal part of nucleus paragigantocellularis lateralis and the rostral part of nucleus lateralis reticularis. SP positive cell bodies in the reticular formation close ventrolateral to nucleus ambiguus were also found. Some 5-HT, SP and L-ENK positive cells were situated in the area near the pia mater. In the most area of the RVL, 5-HT, PNMT, SP and L-ENK immunoreactive cell bodies had an overlapping distribution. 5-HT or PNMT or L-ENK positive neurons crowded, intertwined each other with their processes in the region at the levels 1.0-3.5mm caudal to trapezoid body, about 3.3mm lateral to the midline and about 0.8mm from the ventral surface of the medulla, and formed a longer or shorter continuous cell column which ran in the rostrocaudal direction. These three columns nearly coincided with each other at the level 1.5-2.5mm caudal to trapezoid body. Part of 5-HT, SP and L-ENK positive neurons in the RVL projected into the thoracic cord. The functional significance of these substances in the RVL was also discussed.

Objective:To explore the technique and clinical effects of free medial plantar flap on reconstruction of the severe defect of thumb caused by electric burn.Methods:Surgical techniques and clinical effects were explored in reconstruction with free medial plantar flap for treatment of severe electric burns of thumbs. From July 2016 to July 2021, 18 patients suffered from severe electric burns of thumbs were admitted in the Department of Burn, Zhengzhou First People's Hospital. All the wounds were the entrance of electric burns. After thorough debridement, the arteries, nerves, tendons, phalanges and interphalangeal joints were exposed to various degrees. Damaged digital proper palmar arteries were ligated and defected proper palmar digital nerves were marked and further anastomosed with the nerves carried by the flap. Palmaris longus tendon grafts were employed to reconstruct the defects of flexor pollicis longus tendon. Wounds were closed by transfer of free medial plantar flaps, and the flap donor sites were closed by inguinal skin grafts. Survival of the flap was observed 1 week after surgery, and the survival of the skin graft in the foot donor site 12 days after surgery. Outpatient follow-up including observation of the appearance and texture of the flap, evaluation of sensory function, thumb alignment and finger flexion according to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association. Evaluate the scar hyperplasia in the foot donor site and the standing and walking functions of the donor foot.Results:All flaps survived,at 1 week after surgery. On the 12th day after surgery, all 16 foot flap survived, and 2 patients had local necrosis, and the necrosis healed completely after dressing change for 10 days, the wound healed completely. Among them, 3 patients without tendon transfer experienced a rupture of the flexor pollicis longus tendon at 2 months after surgery, and underwent another palmaris longus tendon transfer. After the surgery, functional exercise was performed with the palm and flexor fingers. After 6-12 months of follow-up, the blood supply, appearance, and texture of the flap were good and similar to that of the palmar skin of the thumb, with varying degrees of recovery in sensation. The TPD was 6-11 mm, and the thumb was restored to varying degrees. According to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, 13 cases in excellent and 5 cases in good. Mild scar hyperplasia remains in the flap site of donor feet, which does not affect the standing and walking functions of the donor foot.Conclusion:The texture of medial plantar skin is similar to that of palmar skin, with good wear resistance and good sensation. Furthermore, it causes a little damage to the donor site and without obvious complication. The medial plantar flap is ideal for reconstruction of a severe wound caused by electric burn in thumb.