Concept for postoperative analgesia after pedicled TRAM flaps: continuous wound instillation with 0.2% ropivacaine via multilumen catheters. A report of two cases

Application of Botulinum Neurotoxin Injections in TRAM Flap for Breast Reconstruction: Intramuscular Neural Arborization of the Rectus Abdominis Muscle

Breast reconstruction after mastectomy is commonly performed using transverse rectus abdominis myocutaneous (TRAM) flap. Previous studies have demonstrated that botulinum neurotoxin injections in TRAM flap surgeries lower the risk of necrosis and allow further expansion of arterial cross-sectional diameters. The study was designed to determine the ideal injection points for botulinum neurotoxin injection by exploring the arborization patterns of the intramuscular nerves of the rectus abdominis muscle. A modified Sihler's method was performed on 16 rectus abdominis muscle specimens. Arborization of the intramuscular nerves was determined based on the most prominent point of the xyphoid process to the pubic crest. All 16 rectus abdominis muscle specimens were divided into four muscle bellies by the tendinous portion. The arborized portions of the muscles were located on the 5-15%, 25-35%, 45-55%, and 70-80% sections of the 1st, 2nd, 3rd, and 4th muscle bellies, respectively. The tendinous portion was located at the 15-20%, 35-40%, 55-60%, and 90-100% sections. These results suggest that botulinum neurotoxin injections into the rectus abdominis muscles should be performed in specific sections.

Design, synthesis and biological activity evaluation of benzoate compounds as local anesthetics

Tetracaine and pramocaine were used as the lead compounds to design benzoate compounds. The combination principle was used to design the target molecule, and the target molecule was modified by bioisostere formation and modification with alkyl groups. In this research, a total of 16 compounds were designed and synthesized. In the process of synthesis, we selected a route with high total yields, mild conditions and simple operation. Three steps were used in the synthesis of the new target compounds, namely, alkylation, esterification and alkylation. The newly designed target compounds were evaluated via surface anesthesia, infiltration anesthesia, block anesthesia and acute toxicity tests. The results of biological activity experiments showed that compounds 4d, 4g, 4j, 4k, 4n, and 4o had a good local anesthetic effect, and the results of acute toxicity tests showed that the target compounds had low toxicity.

Tetracaine and pramocaine were used as the lead compounds to design benzoate compounds.

Synthesis and biological activities of local anesthetics

Local anesthetics are mainly used in stomatology, ophthalmology, gynecology and surgery to temporarily relieve pain. Local anesthetics act on nerve endings or around nerve trunks, and are combined with specific sodium ion (Na⁺) channel sites on the nerve membrane. They can affect the membrane potential by reducing Na⁺ passage through sodium ion channels, thus blocking the generation and conduction of nerve impulses, reversibly blocking the generation and conduction of sensory nerve impulses. Local anesthetics are used for convenience in local surgical operations and treatments. Herein, we mainly review the research progress on local anesthetics and discuss the important aspects of design, synthesis and biological activity of various new compounds.

Local anesthetics are mainly used in stomatology, ophthalmology, gynecology and surgery to temporarily relieve pain.

A comparison of cervical epidural analgesia and intravenous patient-controlled analgesia after mastectomy with immediate latissimus dorsi flap breast reconstruction

BACKGROUND

Breast reconstruction following mastectomy has become increasingly popular in recent years. The purpose of this study was to compare the efficacy of cervical epidural patient-controlled analgesia (CEA) and intravenous patient-controlled analgesia (IV-PCA) for controlling the postoperative pain and the side effects after mastectomy with immediate Latissimus dorsi (LD) flap breast reconstruction.

METHODS

Sixty patients who were to undergo mastectomy with immediate LD flap breast reconstruction were randomly assigned to receive CEA [Group CEA, (n = 30), 0.15% ropivacaine + fentanyl 4 microg/ml] or IV-PCA [Group IV-PCA (n = 30) fentanyl 20 microg/kg + ketorolac 3 mg/kg] for postoperative pain control via a PCA pump (basal rate: 2 ml/h, bolus: 2 ml, lock out interval: 15 min) after their operation. Before general anesthesia, an epidural catheter was inserted at the cervical (C)7-thoracic (T)1 level in the patients of the CEA group. The resting visual analogue scale (VAS) for pain, the systolic blood pressure, the heart rate and the side effects were recorded for 48 hours after operation.

RESULTS

The VAS at rest was significantly lower in the CEA group than that in the IV-PCA group at 16 hours after surgery. The CEA group required less additional analgesics as compared with the group IV- PCA. There were no significant differences in the systolic blood pressure, the heart rate and the incidence of side effects between the two groups.

CONCLUSIONS

We conclude that cervical epidural analgesia, as compared with intravenous patient-controlled analgesia, provides effective pain control and it shows a similar incidence of side effects after mastectomy with immediate LD flap breast reconstruction.

Ventricular Standstill

Transverse rectus abdominus myocutaneous (TRAM) flap is one of the commonly used techniques for breast reconstruction. Postoperative pain relief is of paramount importance following TRAM flap breast reconstruction to avoid potentially preventable complications like chest infection. Several methods of pain control are available, including intrapleural anesthesia. Here we report a case of a patient who developed ventricular standstill as a complication of intrapleural bupivacaine.

Safety of 96-Hour Incision-Site Continuous Infusion of Ropivacaine for Postoperative Analgesia After Bowel Cancer Resection

The aim of this study was to examine the safety of ropivacaine given to patients as a continuous infusion [0.2% (2 mg/mL), 5 mL/h for 96 hours] into a right lateral transverse incision using a portable elastomeric infusion pump after colon cancer resection. Blood samples were collected throughout the infusion and up to 12 hours after infusion and were analyzed by high-performance liquid chromatography (HPLC) for total and unbound ropivacaine concentrations in plasma. Alpha1 acid glycoprotein (AAG) concentrations were measured at 0 and 48 hours to assess possible changes in ropivacaine protein binding after surgery. Postoperative pain control was assessed using 12 hour visual analog scale (VAS) scores. Patient-controlled analgesia (PCA) using fentanyl was freely available in parallel for breakthrough pain, with usage and consumption compared with a historical cohort. The mean +/- SD Cmax total plasma ropivacaine concentration (n = 5) from 12 hours to the end of the infusion was 4.5 +/- 2.6 mg/L, comparable with the previously published threshold for CNS toxicity in the most sensitive patient studied (3.4 mg/L). However, the corresponding maximum unbound ropivacaine concentration (ie, the pharmacologically active moiety) of 0.07 +/- 0.01 mg/L ranged from four- to sevenfold below the reported toxicity threshold (0.34 mg/L). The apparently greater safety margin seen with unbound ropivacaine may have resulted from a significant increase (mean 63%, P < 0.05) in AAG concentrations measured at 48 hours after surgery. This reduction resulted from the known AAG reaction after surgical intervention, resulting in a reducing unbound ropivacaine fraction throughout the 96 hour infusion in all patients. Mean subjective 12 hour pain scale scores at rest and on movement showed large variability between patients. No signs or symptoms of ropivacaine toxicity were observed or reported on questioning. In this limited sample, extending the infusion period from the presently approved 48 hours to 96 hours seems to be a safe alternative and/or adjunct to standard opiate analgesia after colorectal surgery using a right lateral transverse incision, hence reducing the incidence of opiate adverse effects and enhancing recovery. Unbound ropivacaine concentrations suggest there is scope for testing elevated doses to enhance efficacy further.