The Importance of the Proximal Saphenous Nerve Block for Foot and Ankle Surgery:

Distal subsartorial compartment block of the saphenous nerve - A dissection study and a patient case series

STUDY OBJECTIVE

A saphenous nerve block is an important tool for analgesia after foot and ankle surgery. The conventional midthigh approach to saphenous nerve block in the femoral triangle may impede ambulation by impairing quadriceps motor function.

PRIMARY OBJECTIVE

Developing a selective saphenous nerve block targeting the nerve distal to its emergence from the adductor canal in the subsartorial compartment.

DESIGN

This study consists of A) a dissection study and B) Data from a clinical case series.

SETTING

A) Medical University of Innsbruck, Austria (dissection of 15 cadaver sides) and. B) Aarhus University Hospital, Denmark (5 patients).

INTERVENTIONS

A) Five mL of methylene blue was injected into the subsartorial compartment distal to the intersection of the saphenous nerve and the tendon of the adductor magnus guided by ultrasound. B) Five patients undergoing major hindfoot and ankle surgery had a subsartorial compartment block with 10 mL of local anesthetic in addition to a popliteal sciatic nerve block.

MEASUREMENT

A) The frequencies of staining the saphenous and medial vastus nerves. B) Assessment of postoperative pain by NRS score (0-10) and success rate of saphenous nerve block by presence of cutaneous anesthesia in the anteromedial lower leg, and motor impairment by ability to ambulate.

MAIN RESULTS

A) The saphenous nerve was stained in 15/15 cadaver sides. A terminal branch of the medial vastus nerve was stained in 2/15 cadaver sides. B) All patients were fully able to ambulate without support. No patients had any post-surgical pain from the anteromedial aspect of the ankle and foot (NRS score 0). The success rate of saphenous nerve block was 100%.

CONCLUSION

The saphenous nerve can be targeted in the subsartorial compartment distal to the intersection of the nerve and the tendon of the adductor magnus. The subsartorial compartment block provided efficient analgesia without quadriceps motor impairment.

Comparison of Single-Agent Versus 3-Additive Regional Anesthesia for Foot and Ankle Surgery

BACKGROUND

This study compared the results of regional blocks containing a single anesthetic, bupivacaine, with those containing bupivacaine and 3 additives (buprenorphine, clonidine, and dexamethasone) in patients undergoing foot and ankle surgery.

METHODS

Eighty patients undergoing foot and ankle surgery over a 9-month period were prospectively enrolled and randomized to receive a peripheral nerve block containing either a single anesthetic (SA) or one with 3 additives (TA). Patients, surgeons, and anesthesiologists were blinded to the groups. Patients maintained pain diaries and were evaluated at 1 and 12 weeks postoperatively. Fifty-six patients completed the study.

RESULTS

The TA group had a longer duration of analgesic effect than the SA group (average 82 vs 34 hours, P < .05). Forty-eight hours after surgery, 93% of SA blocks, compared with 34% of TA blocks, had completely worn off. The TA group had a longer duration of sensory effects. At 3 months, 10 of 26 (38.5%) TA patients, compared with 3 of 30 (10%) SA patients, reported postoperative neurologic symptoms. Pain scores in both groups were not statistically different at 1 week or 3 months after surgery. Patients in both groups were similarly satisfied with their blocks.

CONCLUSION

Both types of nerve blocks provided equivalent pain control and patient satisfaction in patients undergoing foot and ankle surgery. The 3-additive agent blocks were associated with a longer duration of pain relief and a longer duration of numbness, as well as higher rates of postoperative neurologic symptoms. Longer pain relief may be obtained at the cost of prolonged sensory deficits.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Pretreatment of ankle nerve block provides better postoperative analgesia than peri-incisional local anesthetic infiltration in hallux valgus correction surgery

Adequate postoperative analgesia after hallux valgus (HV) correction surgery improves early mobilization and decreases hospital stay. Peripheral nerve block and peri-incisional local anesthetic (LA) infiltration are both widely used for pain management in orthopedic surgeries. The aim of this study was to compare the analgesic effects between the ankle block and peri-incisional infiltration technique in patients undergoing HV correction surgery. Ninety patients scheduled for hallux valgus correction surgery were randomly allocated into three groups. In group N, patients were pretreated with tibial and peroneal nerve blocks with 8-10 mL of 0.25% bupivacaine before surgery. In group P, patients received the same LA for peri-incisional infiltration preoperatively. In group C, patients underwent surgery without regional analgesic pretreatment. All patients had intravenous fentanyl patient control analgesia as part of multimodal postoperative pain management. Fentanyl consumption, rest and moving pain scale, and adverse effects were evaluated at postoperative 6 h (Poh6), Poh12, Poh 24, and Poh36, respectively. Patients receiving bilateral feet surgeries were excluded in this study. Seventy-five patients were enrolled into final analysis. The patients in group N expressed lower resting and moving pain scores at Poh6, but the pain scores turned similarly among the three groups following Poh12 and then. The total fentanyl consumption was significantly less in group N than in group P. The postoperative activities and mood disturbance were not significantly different between groups after Poh12 and then. We conclude that ankle block is better than peri-incisional LA infiltration in HV correction surgery in pain relief and fentanyl consumption.

The Importance of the Saphenous Nerve Block for Analgesia Following Major Ankle Surgery: A Randomized, Controlled, Double-Blind Study

BACKGROUND AND OBJECTIVES

Major ankle surgery causes intense postoperative pain, and whereas the importance of a sciatic nerve block is well established, the clinical significance of a supplemental saphenous nerve block has never been determined in a prospective, randomized, double-blind, placebo-controlled trial. We hypothesized that a saphenous nerve block reduces the proportion of patients experiencing significant clinical pain after major ankle surgery.

METHODS

Eighteen patients were enrolled and received a popliteal sciatic nerve block. Patients were randomized to single-injection saphenous nerve block with 10 mL 0.5% bupivacaine with 1:200,000 epinephrine or 10 mL saline (Fig. 1). Primary outcome was the proportion of patients reporting significant clinical pain, defined as a score greater than 3 on the numerical rating scale. Secondary outcomes were maximal pain and analgesia of the cutaneous territory of the infrapatellar branch of the saphenous nerve.

RESULTS

Eight of 9 patients in the placebo group reported significant clinical pain versus 1 of 9 patients in the bupivacaine-epinephrine group (P = 0.003). Maximal pain was significantly lower in the active compared with the placebo group (median, 0 [0-0] vs 5 [4-6]; P = 0.001). Breakthrough pain from the saphenous territory began within 30 minutes after surgery in all cases. Sensory testing of the cutaneous territory of the infrapatellar branch of the saphenous nerve showed correlation between pain reported in the anteromedial ankle region and the intensity of cutaneous sensory block in the anteromedial knee region.

CONCLUSIONS

The saphenous nerve is an important contributor to postoperative pain after major ankle surgery, with significant clinical pain appearing within 30 minutes after surgery.

CLINICAL TRIALS REGISTRATION

This study has been registered at ClinicalTrials.gov, identifier NCT02697955.

Effect of Perineural Dexamethasone on the Duration of Single Injection Saphenous Nerve Block for Analgesia After Major Ankle Surgery: A Randomized, Controlled Study

BACKGROUND AND OBJECTIVES

Patients undergoing major elective ankle surgery often experience pain from the saphenous nerve territory persisting beyond the duration of a single-injection saphenous nerve block. We hypothesized that perineural dexamethasone as an adjuvant for the saphenous nerve block prolongs the duration of analgesia and postpones as well as reduces opioid-requiring pain.

METHODS

Forty patients were included in this prospective, randomized, controlled study. All patients received a continuous sciatic catheter and were randomized to receive a single-injection saphenous nerve block with 10 mL of 0.5% bupivacaine with 1:200,000 epinephrine with addition of 1 mL of saline or 1 mL of 0.4% (ie, 4 mg) dexamethasone. The primary outcome was duration of saphenous nerve block estimated as the time until the first opioid request. Secondary outcomes were opioid consumption and pain.

RESULTS

The mean (SD) duration of the saphenous nerve block until first opioid request was 29.4 (8.4) hours in the dexamethasone group and 23.2 (10.3) hours in the control group (P = 0.048). The median opioid consumption [interquartile range] during the first 24 hours was 0 mg [0-0] versus 1.5 mg [0-14.2] in the dexamethasone and control groups, respectively. Nonparametric comparison of opioid consumption from 0 to 24 hours was statistically significant. The opioid consumption was similar in the two groups in the time interval 24 to 48 postoperative hours.

CONCLUSION

Perineural dexamethasone as an adjuvant for the single-injection subsartorial saphenous nerve block can prolong analgesia and reduce opioid-requiring pain after major ankle surgery.

Complications After Multiple-Site Peripheral Nerve Blocks for Foot and Ankle Surgery Compared With Popliteal Sciatic Nerve Block Alone

BACKGROUND

Single or combined multiple-site peripheral nerve blocks (PNBs) are becoming popular for patients undergoing surgery on their feet or ankles. These procedures are known to be generally safe in surgical settings compared with other forms of anesthesia, such as spinal block. The purposes of this study were to assess the incidence of complications after the administration of multiple PNBs for foot and ankle surgery and to compare the rates of complications between patients who received a single PNB and those who received multiple blocks.

METHODS

Charts were reviewed retrospectively to assess peri- and postoperative complications possibly related to the PNBs. The records of 827 patients who had received sciatic nerve blocks, femoral nerve blocks adductor canal blocks, or combinations of these for foot and/or ankle surgery were analyzed for complications. The collected data consisted of age, sex, body mass index, presence of diabetes mellitus, smoking history, tourniquet time, and complications both immediately postoperatively and 1 year later.

RESULTS

Of these 827 patients, 92 (11.1%) developed neurologic symptoms after surgery; 22 (2.7%) of these likely resulted from the nerve blocks, and 7 (0.8%) of these were unresolved after the patients' last follow-up visits. There were no differences in complication rates between combined blocks and single sciatic nerve blocks.

CONCLUSION

There were more complications, both transient and long term, after anesthetic PNBs than previous literature has reported. Combined multiple-site blocks did not increase the rate of neurologic complications.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Combined Popliteal Catheter With Single-Injection vs Continuous-Infusion Saphenous Nerve Block for Foot and Ankle Surgery

BACKGROUND

The increasing scope and complexity of foot and ankle procedures performed in an outpatient setting require more intensive perioperative analgesia. Regional anesthesia (popliteal and saphenous nerve blocks) has been proven to provide satisfactory pain management, decreased postoperative opioid use, and earlier patient discharge. This can be further augmented with the placement of a continuous-flow catheter, typically inserted into the popliteal nerve region. This study investigated the use of a combined popliteal and saphenous continuous-flow catheter nerve block compared to a single popliteal catheter and single-injection saphenous nerve block in postoperative pain management after ambulatory foot and ankle surgery.

METHODS

A prospective study was conducted using 60 patients who underwent foot and ankle surgery performed in an outpatient setting. Demographic data, degree of medial operative involvement, American Society of Anesthesiologists physical classification system, anesthesia time, and postanesthesia care unit time were recorded. Outcome measures included pain satisfaction, numeric pain scores (NPS) at rest and with activity, and opioid intake. Patients were also classified by degree of saphenous nerve involvement in the operative procedure, by the surgeon who was blinded to the anesthesia randomization.

RESULTS

Patients in the dual-catheter group took significantly less opioid medication on the day of surgery and postoperative day 1 (POD 1) compared to the single-catheter group ( P = .02). The dual-catheter group reported significantly greater satisfaction with pain at POD 1 and POD 3 and a significantly lower NPS at POD 1, 2, and 3. This trend was observed in all 3 subgroups of medial operative involvement.

CONCLUSION

Patients in the single-catheter group reported more pain, less satisfaction with pain control, and increased opioid use on POD 1, suggesting dual-catheter use was superior to single-injection nerve blocks with regard to managing early postoperative pain in outpatient foot and ankle surgery.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Adductor canal block versus femoral nerve block combined with sciatic nerve block as an anesthetic technique for hindfoot and ankle surgery: A prospective, randomized noninferiority trial

BACKGROUND

A femoral nerve block (FNB) in combination with a sciatic nerve block (SNB) is commonly used for anesthesia and analgesia in patients undergoing hindfoot and ankle surgery. The effects of FNB on motor function, related fall risk, and rehabilitation are controversial. An adductor canal block (ACB) potentially spares motor fibers in the femoral nerve, but the comparative effect on hindfoot and ankle surgeries between the 2 approaches is not yet well defined. We hypothesized that compared to FNB, ACB would cause less weakness in the quadriceps and produce similar pain scores during and after the operation.

METHODS

Sixty patients scheduled for hindfoot and ankle surgeries (arthroscopy, Achilles tendon surgery, or medial ankle surgery) were stratified randomized for each surgery to receive an FNB (FNB group) or an ACB (ACB group) combined with an SNB. The primary outcome was the visual analog scale (VAS) pain score at each stage. Secondary outcomes included quadriceps strength, time profiles (duration of the block procedure, time to full anesthesia and time to full recovery), patients' analgesic requirements, satisfaction, and complications related to peripheral nerve blocks such as falls, neurologic symptoms, and local anesthetic systemic toxicity were evaluated. The primary outcome was tested for the noninferiority of ACB to FNB, and the other outcomes were tested for the superiority of each variable between the groups.

RESULTS

A total of 31 patients received an ACB and 29 received an FNB. The VAS pain scores of the ACB group were not inferior during and after the operation compared to those of the FNB group. At 30 minutes and 2 hours after anesthesia, patients who received an ACB had significantly higher average dynamometer readings than those who received a FNB (34.2 ± 20.4 and 30.4 ± 23.7 vs 1.7 ± 3.7 and 2.3 ± 7.4, respectively), and the results were similar at 24 and 48 hours after anesthesia. There were no differences between the 2 groups with regard to time profiles and patient satisfaction. No complications were noted.

CONCLUSION

ACB preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative pain. Therefore, ACB may be a good alternative to FNB for reducing the potential fall risk.

Ultrasound-Guided Interventional Procedures in Pain Medicine: A Review of Anatomy, Sonoanatomy, and Procedures: Part VI: Ankle Joint

Ultrasound-guided injections in pain medicine are emerging as a popular technique for pain interventions. Ultrasound can be applied for procedures of the ankle joint and surrounding structures. This review describes the anatomy and sonoanatomy of the ankle joint, subtalar joint, and surrounding extra-articular structures relevant for intra-articular injection. Second, it reviews injection techniques and the accuracy and efficacy of these intra-articular ankle injections.

Peripheral nerve blocks for ambulatory surgery

Peripheral nerve blocks (PNBs) provide significant improvement in postoperative analgesia and quality of recovery for ambulatory surgery. Use of continuous PNB techniques extend these benefits beyond the limited duration of single-injection PNBs. The use of ultrasound guidance has significantly improved the overall success, efficiency, and has contributed to the increased use of PNBs in the ambulatory setting. More recently, the use of ultrasound guidance has been demonstrated to decrease the risk of local anesthetic systemic toxicity. This article provides a broad overview of the indications and clinically useful aspects of the most commonly used upper and lower extremity PNBs in the ambulatory setting. Emphasis is placed on approaches that can be used for single-injection PNBs and continuous PNB techniques.