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.

Pain relief after major ankle and hindfoot surgery with repetitive peripheral nerve blocks: A feasibility study.

BACKGROUND: Major ankle and hindfoot surgery (e.g., ankle, triple and subtalar arthrodesis) typically causes severe postoperative pain, especially the first two postoperative days. Current modalities of postoperative analgesic treatment often include continuous peripheral nerve blocks of the saphenous and sciatic nerves via catheters in order to extend the duration of pain- and opioid-free nerve blockade to 48 h. Unfortunately, the 48 h-efficacy of continuous infusion via a catheter is reduced by a high displacement rate. We hypothesised that one-time repetition of the single injection peripheral nerve blocks would provide effective analgesia with a low opioid consumption the first 48 postoperative hours. METHODS: Eleven subjects preoperatively received a popliteal sciatic and a saphenous single injection nerve block with a protracted local anaesthetic mixture. Surgery was performed under general anaesthesia. The one-time repetition of the single injection nerve block was carried out approximately 24 h after the primary nerve block. The main outcomes were pain and cumulative opioid consumption during the first 48 postoperative hours. RESULTS: Nine of the 11 (82%) patients had effective analgesia without opioids during the first 48 postoperative hours. Two patients each required a single dose of 7.5 mg of oral morphine equivalents after 43 h. CONCLUSION: One-time repetition of single injection saphenous and sciatic nerve blocks consistently provided effective analgesia practically without opioids for 48 h after major elective ankle and hindfoot surgery.

The anterior branch of the medial femoral cutaneous nerve innervates the anterior knee: a randomized volunteer trial.

BACKGROUND: The midline skin incision for total knee arthroplasty may be an important generator of chronic neuropathic pain. The incision is innervated by the medial femoral cutaneous nerve (MFCN), the intermediate femoral cutaneous nerves (IFCN) and the infrapatellar branch from the saphenous nerve. The MFCN divides into an anterior (MFCN-A) and a posterior branch (MFCN-P). The primary aim was to compare the areas anesthesized by MFCN-A versus MFCN-P block for coverage of the incision. METHODS: Nineteen healthy volunteers had IFCN and saphenous nerve blocks. The subgroup of volunteers with a non-anesthetized gap between the areas anesthetized by the saphenous and the IFCN blocks was defined as the study group for the primary outcome. Subsequently selective MFCN-A block and MFCN block (MFCN-A + MFCN-P) were performed to investigate the contributions from MFCN-A and MFCN-P to the innervation of the midline incision. All assessments were performed blinded. RESULTS: Ten out of 19 volunteers had a non-anesthetized gap. Nine out of these 10 volunteers had coverage of the non-anesthetized gap after selective anesthesia of the MFCN-A, whereas anesthesia of the MFCN-P did not contribute to coverage of the gap in any of the 10 volunteers. CONCLUSIONS: In half of the cases, a gap of non-anesthetized skin was present on the surgical midline incision after anesthesia of the saphenous nerve and the IFCN. This gap was covered by selective anesthesia of the MFCN-A without contribution from MFCN-P. The selective MFCN-A block may be relevant for diagnosis and interventional management of neuropathic pain due to injury of MFCN-A.

Brachial Plexus Block with Liposomal Bupivacaine for Shoulder Surgery Improves Analgesia and Reduces Opioid Consumption: Results from a Multicenter, Randomized, Double-Blind, Controlled Trial.

OBJECTIVE: The utility of single-injection and continuous peripheral nerve blocks is limited by short duration of analgesia and catheter-related complications, respectively. This double-blind, multicenter trial evaluated the efficacy, safety, and pharmacokinetics of single-injection, ultrasound-guided brachial plexus block (BPB) with liposomal bupivacaine (LB) added to a standardized pain management protocol for shoulder surgery. METHODS: Adults undergoing total shoulder arthroplasty or rotator cuff repair were randomized to receive LB 133 mg, LB 266 mg (pharmacokinetic and safety analyses only), or placebo, added to a standardized analgesia protocol. The primary end point was area under the curve (AUC) of visual analog scale pain intensity scores through 48 hours postsurgery. Secondary end points were total opioid consumption, percentage of opioid-free patients, and time to first opioid rescue through 48 hours. Pharmacokinetic samples were collected through 120 hours and on days 7 and 10. Adverse events were documented. RESULTS: One hundred fifty-five patients received treatment (LB 133 mg, N = 69; LB 266 mg, N = 15; placebo, N = 71). BPB with LB 133 mg was associated with significantly improved AUC of pain scores (least squares mean [SE] = 136.4 [12.09] vs 254.1 [11.77], P < 0.0001), opioid consumption (least squares mean [SE] = 12.0 [2.27] vs 54.3 [10.05] mg, P < 0.0001), median time to opioid rescue (4.2 vs 0.6 h, P < 0.0001), and percentage of opioid-free patients (treatment difference = 0.166, 95% confidence interval = 0.032-0.200, P = 0.008) through 48 hours vs placebo. Adverse event incidence was comparable between groups. CONCLUSIONS: Single-injection BPB with LB 133 mg provided analgesia through 48 hours postsurgery with reduced opioid use compared with placebo after shoulder surgery.

An iliopsoas plane block does not cause motor blockade-A blinded randomized volunteer trial.

BACKGROUND: A femoral nerve block relieves pain after total hip arthroplasty, but its use is controversial due to motor paralysis accompanied by an increased risk of fall. Assumedly, the iliopsoas plane block (IPB) targets the hip articular branches of the femoral nerve without motor blockade. However, this has only been indicated in a cadaver study. Therefore, we designed this volunteer study. METHODS: Twenty healthy volunteers were randomly allocated to blinded paired active vs. sham IPB (5 mL lidocaine 18 mg/mL with epinephrine vs saline). The primary outcome was reduction of maximal force of knee extension after IPB compared to baseline. Secondary outcomes included reduction of maximal force of hip adduction, and the pattern of injectate spread assessed with magnetic resonance imaging. RESULTS: Mean (confidence interval) change of maximal force of knee extension from baseline to after IPB was -9.7 N (-22, 3.0) (P = .12) (n = 14). The injectate was consistently observed in an anatomically well-defined closed fascial compartment between the intra- and extra-pelvic components of the iliopsoas muscle anterior to the hip joint. CONCLUSION: We observed no significant reduction of maximal force of knee extension after an IPB. The injectate was contained in a fascial compartment previously shown to contain all sensory branches from the femoral nerve to the hip joint. The clinical consequence of selective anesthesia of all sensory femoral nerve branches from the hip could be a reduced risk of fall compared to a traditional femoral nerve block. Registration of Trial: The trial was prospectively registered in EudraCT (Reference: 2018-000089-12, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2018-000089-12).

Peripheral nerve catheters: A critical review of the efficacy.

Continuous peripheral nerve blocks are commonly used for postoperative analgesia after surgery. However, catheter failure may occur due to either primary (incorrect insertion) or secondary reasons (displacement, obstruction, disconnection). Catheter failure results in unanticipated pain, need for opioid use, and risk of readmission or delay in hospital discharge. This review aimed to assess definition and frequency of catheter failure, and discuss the alternatives to prolong duration of single-shot nerve blocks. A literature search was performed on peripheral catheters reporting failure as the main outcome measure. Thirty-three studies met the selection criteria, comprising 2711 catheters. Literature review suggests that peripheral nerve catheters have clinically significant failure rate when the assessment is performed using an objective (imaging) method. Subjective methods of assessment (without imaging) may underestimate the incidence of catheter failure.

Are single-injection erector spinae plane block and multiple-injection costotransverse block equivalent to thoracic paravertebral block?

BACKGROUND: Thoracic paravertebral block (TPVB) is considered the gold standard for hemithoracic regional anaesthesia. Erector spinae plane block (ESPB) is a new posterior thoracic wall block. Multiple-injection costotransverse block (MICB) mimics TPVB but with injection points within the thoracic intertransverse tissue complex and posterior to the superior costotransverse ligament. We aimed to compare the spread of injectate into the thoracic paravertebral space (TPVS) resulting from single-injection ESPB and MICB, respectively, with TPVB. METHODS: Ten soft-embalmed cadavers were utilised. In five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided single-injection ESPB or single-injection TPVB; vice versa on the other side. In another five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided MICB or multiple-injection TPVB. About 20 mL of dye was injected in each hemithorax with all techniques. RESULTS: With TPVB, the dye was consistently present in the TPVS with concomitant epidural spread in the majority of cases. The injectate spread into the TPVS with ESPB (60%) and MICB (100%). MICB consistently stained the ventral rami (T1-7), communicating rami and thoracic sympathetic trunk without epidural spread. Dissection after MICB revealed dye spread into the TPVS via the costotransverse foramina and along the dorsal branches of the posterior intercostal veins. CONCLUSIONS: Consistent spread of dye into the TPVS colouring the ventral rami, the communicating rami, and the sympathetic trunk was observed with MICB; in this respect equivalent to TPVB. ESPB exhibited only partial success and was not equivalent to TPVB. No epidural spread was found with neither MICB nor ESPB.

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy reduces opioid consumption and speeds ambulation and discharge from hospital: a single centre randomised controlled trial.

BACKGROUND: Percutaneous nephrolithotomy (PNL) is associated with severe postoperative pain. The current study aimed to investigate the analgesic efficacy of transmuscular quadratus lumborum (TQL) block for patients undergoing PNL surgery. METHODS: Sixty patients were enrolled in this single centre study. The multimodal analgesic regime consisted of oral paracetamol 1 g and i.v. dexamethasone 4 mg before surgery and i.v. sufentanil 0.25 µg kg-1 30 min before emergence. After operation, patients received paracetamol 1 g regularly at 6 h intervals. Subjects were allocated to receive a preoperative TQL block with either ropivacaine 0.75%, 30 ml (intervention) or saline 30 ml (control). Primary outcome was oral morphine equivalent (OME) consumption 0-6 h after surgery. Secondary outcomes were OME consumption up to 24 h, pain scores, time to first opioid, time to first ambulation, and hospital length of stay. Results were reported as mean (standard deviation) or median (inter-quartile range). RESULTS: Morphine consumption was lower in the intervention group at 6 h after surgery (7.2 [8.7] vs 90.6 [69.9] mg OME, P<0.001) and at 24 h (54.0 [36.7] vs 126.2 [85.5] mg OME, P<0.001). Time to first opioid use was prolonged in the intervention group (678 [285-1020] vs 36 [19-55] min, P<0.0001). Both the time to ambulation (302 [238-475] vs 595 [345-925] min, P<0.004) and length of stay (2.0 [0.8] vs 3.0 [1.2] days, P≤0.001) were shorter in the intervention group. CONCLUSIONS: This is the first blinded, RCT that confirms that unilateral TQL block reduces postoperative opioid consumption and hospital length of stay. Further study is required for confirmation and dose optimisation. CLINICAL TRIAL REGISTRATION: NCT02818140.

The Lateral Femoral Cutaneous Nerve: Description of the Sensory Territory and a Novel Ultrasound-Guided Nerve Block Technique.

BACKGROUND AND OBJECTIVES: Nerve blockade of the lateral femoral cutaneous (LFC) nerve provides some analgesia after hip surgery. However, knowledge is lacking about the extent of the cutaneous area anesthetized by established LFC nerve block techniques, as well as the success rate of anesthetic coverage of various surgical incisions. Nerve block techniques that rely on ultrasonographic identification of the LFC nerve distal to the inguinal ligament can be technically challenging. Furthermore, the branching of the LFC nerve is variable, and it is unknown if proximal LFC nerve branches are anesthetized using the current techniques. The primary aim of this study was to investigate a novel ultrasound-guided LFC nerve block technique based on injection into the fat-filled flat tunnel (FFFT), which is a duplicature of the fascia lata between the sartorius and the tensor fasciae latae muscle, in order to assess the success rate of anesthetizing the proximal LFC nerve branches and covering of the different surgical incisions used for hip surgery. METHODS: First, a cadaveric study was conducted in order to identify an FFFT injection technique that would provide adequate injectate spread to the proximal LFC nerve branches. Second, a clinical study was conducted in a group of 20 healthy volunteers over 2 consecutive days. On trial day 1, successful complete anesthesia of the LFC nerve was defined by performing a suprainguinal fascia iliaca block bilaterally in each subject. On trial day 2, a triple-blind randomized controlled trial compared the effect of the novel ultrasound-guided LFC nerve block technique for bupivacaine versus placebo. The primary end point was the success rate of anesthesia of the proximal cutaneous area innervated by the LFC nerve for the FFFT injection with bupivacaine versus placebo. RESULTS: Adequate spread of injectate to the proximal LFC nerve branches in cadavers was obtained by injecting 10 mL with dynamic needle-tip tracking in the FFFT. Application of this technique in the randomized controlled trial provided anesthesia of the lateral thigh with a success rate of 95% (95% confidence interval, 73.9%-99.8%) for the active side and 0% for placebo (P < 0.001). The proximal branches were anesthetized with a success rate of 68% (95% confidence interval, 43.4%-87.4%) on the active side. The proximal extent of the anesthetized cutaneous area was on average 7.9 cm distal to the greater trochanter. CONCLUSIONS: This novel LFC nerve block technique is easy and quick and reliably produces anesthesia of the lateral thigh. The greater trochanter is rarely included in the area of anesthesia, which reduces the coverage of each specific surgical incision. The success rate of 68% in anesthetizing the proximal nerve branches must be further evaluated by future research.

Superiority of ultrasound-guided Shamrock lumbar plexus block.

Ultrasound-guided lumbar plexus block (LPB) performed with the Shamrock approach has received much interest since the technique was first described in 2013. The technique is believed to be faster and easier to perform and possibly safer in regards to potential complications compared with other LPBs. In order to outline some favorable characteristics of the Shamrock LPB, we performed an exhaustive search of the current literature; even though it is rather limited. We have related the evidence to our own clinical experience about the block execution. We present a narrative review of the alleged superiority of the ultrasound-guided Shamrock LPB. Our aim was to assess some of the characteristics that we believe differentiate the Shamrock technique from other ultrasound-guided LPB techniques. We present graphical directions about how to carry out the Shamrock block, and we present novel magnetic resonance images illustrating the injectate spread around the lumbar plexus within the intrapsoas compartment after Shamrock guided injection of contrast enhanced local anesthetic. The Shamrock approach is easier, faster and better to visualise the LPB compared to other LPB techniques. The needle trajectory and needle tip location just lateral to the lumbar plexus probably reduces the risk of adverse effects and complications. Ultrasound guided lumbar plexus blockade is an expert technique. The Shamrock technique improves but does not eliminate all the challenges of ultrasound-guided LPB technique.

Comparing low volume saphenous-obturator block with placebo and femoral-obturator block for anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament reconstruction (ACL-RC) is often associated with moderate to severe postoperative pain even with a multimodal analgesic regimen. We aimed to compare the analgesic efficacy of low volume saphenous-obturator block with placebo and femoral-obturator block in patients undergoing ACL-RC. METHODS: In a randomized controlled trial eighty-two patients undergoing ACL-RC with hamstring autograft were allocated to either low volume saphenous-obturator block, placebo block or femoral-obturator block. Ropivacaine 0.75% was used for active blocks and saline for placebo. Primary outcome was pain-scores at rest quantified as area-under-the-curve 0-6 hr postoperatively. Secondary outcomes were postoperative opioid consumption and pain localization in the knee. RESULTS: No statistical difference existed between groups in area-under-the-curve 6 hr pain-scores. However, pain-scores were significantly lower in the two ropivacaine groups compared to placebo at emergence t=0 (P<0.018), at t=5 (P<0.042) and at t=6 hours (P<0.002) postoperatively. Furthermore, ropivacaine blocks exhibited significantly reduced total opioid consumption (15.81 and 18.44 mg) postoperatively compared with placebo (26.38 mg) (P<0.018). Patients receiving ropivacaine blocks localized pain in the posterolateral knee, whereas placebo block patients reported anteromedial and central pain. Other secondary outcomes were similar between groups. CONCLUSIONS: Low volume saphenous-obturator block is significantly more effective than placebo in reducing both early and late pain-scores as well as postoperative opioid consumption in patients undergoing ACL-RC. No statistical difference existed when comparing low volume saphenous-obturator block to femoral-obturator block regarding early and late pain-scores and postoperative opioid consumption.

The Pathway of Injectate Spread With the Transmuscular Quadratus Lumborum Block: A Cadaver Study.

BACKGROUND: The spread of injectate resulting from a transmuscular quadratus lumborum (TQL) block and a transverse oblique paramedian (TOP) TQL block has never been examined. The aim of this cadaveric study was to investigate by which pathway the injectate spreads cephalad into the thoracic paravertebral space and which nerves were dyed by the injectate cephalad and caudad to the diaphragm when performing a TQL and a TOP TQL block. We also aimed to investigate whether the thoracic and lumbar sympathetic trunks as well as the lumbar plexus were covered by the injectate. METHODS: Ultrasound-guided bilateral TQL and TOP TQL injections were administered in 8 cadavers. A total of 16 injections were performed. With the TQL injection, the curvilinear transducer was oriented in the transverse plane above the iliac crest at the posterior axillary line to identify the Shamrock sign. With the TOP TQL injection, the same transducer was placed with a TOP orientation 3 cm lateral to the L2 spinous process to identify the L2 transverse process and the adjoining quadratus lumborum muscle. For both techniques, the needle was advanced in-plane to the transducer, with the end point in the interfascial plane between the quadratus lumborum and psoas major muscles. Thirty milliliters of dye solution was injected bilaterally for each technique. The spread of the dye was evaluated by subsequent dissection. RESULTS: In all successful injections, the dye was seen to spread into the thoracic paravertebral space and the intercostal spaces to surround the somatic nerves and the thoracic sympathetic trunk. The main pathway of spread of injectate was posterior to the medial and lateral arcuate ligaments. Caudad to the diaphragm, the injected dye surrounded the subcostal, iliohypogastric, and ilioinguinal nerves in all cases, whereas the genitofemoral and lateral femoral cutaneous nerves were dyed in a varying degree. No dye was seen to surround the lumbar plexus, femoral nerve, or lumbar sympathetic trunk. The pattern of spread was similar with the TQL and TOP TQL injections. CONCLUSIONS: The spread of injectate with the TQL and TOP TQL approaches is cephalad from the lumbar point of administration between the quadratus lumborum and psoas major muscles, predominantly via a pathway posterior to the arcuate ligaments and into the thoracic paravertebral space to reach the somatic nerves and the thoracic sympathetic trunk in the intercostal and paravertebral spaces. The lumbar plexus and lumbar sympathetic trunk are not affected.

Peripheral Neuromodulation for the Treatment of Postamputation Neuroma Pain: A Case Report.

Neuroma pain can be severe, persistent, and treatment resistant. We present a case of a 37-year-old female amputee who suffered from severe neuroma pain, which had proved resistant to pharmacologic treatment, glycerol injections, spinal cord stimulation, radiofrequency thermocoagulation, and repeated surgical removals. After treatment with peripheral nerve stimulation, using a St. Jude Medical Octrode lead implanted percutaneously under ultrasound guidance close to her painful neuroma, her ongoing pain dramatically decreased from 8 to 3 on a numeric rating scale (0-10). Peripheral neuromodulation is a promising relatively new treatment that can be used for neuroma pain.

Low-Volume Brachial Plexus Block Providing Surgical Anesthesia for Distal Arm Surgery Comparing Supraclavicular, Infraclavicular, and Axillary Approach: A Randomized Observer Blind Trial.

Background. Distal arm surgery is widely performed under regional anesthesia with brachial plexus block. The preponderance of evidence for the efficacy relies upon injection of local anesthetic in excess of 30 mL. We aimed to compare three different ultrasound-guided brachial plexus block techniques restricting the total volume to 20 mL. Methods. 120 patients were prospectively randomized to ultrasound-guided brachial plexus block with 20 mL ropivacaine 0.75% at either the supraclavicular, infraclavicular, or axillary level. Multiinjection technique was performed with all three approaches. Primary outcome measure was performance time. Results. Performance time and procedural pain were similar between groups. Needle passes and injection numbers were significantly reduced in the infraclavicular group (P < 0.01). Nerve visibility was significantly reduced in the axillary group (P = 0.01). Success-rate was significantly increased in the supraclavicular versus the axillary group (P < 0.025). Total anesthesia-related time was significantly reduced in the supraclavicular compared to the infraclavicular group (P < 0.01). Block duration was significantly increased in the infraclavicular group (P < 0.05). No early adverse effects occurred. Conclusion. Supraclavicular and infraclavicular blocks exhibited favorable characteristics compared to the axillary block. Supraclavicular brachial plexus block with the multiinjection intracluster technique exhibited significantly reduced total anesthesia-related time and higher success rate without any early adverse events.