Robert Doty

Neurologic sequelae after interscalene brachial plexus block for shoulder/upper arm surgery: The association of patient, anesthetic, and surgical factors to the incidence and clinical course

We determined the incidence, distribution, and resolution of neurologic sequelae and the association with anesthetic, surgical, and patient factors after single-injection interscalene block (ISB) using levobupivacaine 0.625% with epinephrine 1:200,000 in subjects undergoing shoulder or upper arm surgery, or both, in 693 consecutive adult patients. After a standardized ISB, assessments were made at 24 and 48 h and at 2 and 4 wk for anesthesia, hypesthesia, paresthesias, pain/dysesthesias, and motor weakness. Symptomatic patients were monitored until resolution. Subjects reporting pain or discomfort >3 of 10 and those with motor or extending sensory symptoms received diagnostic assessment. Six-hundred-sixty subjects completed 4 wk of follow-up. Fifty-eight neurologic sequelae were reported by 56 subjects. Symptoms were sensory except for two cases of motor weakness (lesions identified distant from the ISB site). Thirty-one sequelae with likely ISB association were reported by 29 subjects, including 14 at the ISB site, 9 at the distal phalanx of thumb/index finger, 7 involving the posterior auricular nerve, and 1 clinical brachial plexopathy. Sequelae not likely associated with the ISB were reported by 27 subjects with symptoms reported in the median (n = 9) and ulnar (n = 4) nerves, surgical neuropraxias (n = 12), and motor weakness (n = 2). Symptoms resolved spontaneously (median 4 wk; range, 2–16 wk) except in the two patients with motor weaknesses and the patient with clinical brachial plexopathy, who received therapeutic interventions. Variables identified as independent predictors of neurologic sequelae likely related to ISB were paresthesia at needle insertion and ISB site pain or bruising at 24 h. In contrast, surgery preformed in the sitting position, as well as ISB site bruising, was identified as a predictor of neurologic sequelae not likely related to ISB. In conclusion, neurologic sequelae after single-injection ISB using epinephrine mainly involve transient minor sensory symptoms.

The effects of perineural versus intravenous dexamethasone on sciatic nerve blockade outcomes: A randomized, double-blind, placebo-controlled study

BACKGROUND:Perineural dexamethasone has been investigated as an adjuvant for brachial plexus nerve blocks, but it is not known whether the beneficial effect of perineural dexamethasone on analgesia duration leads to a better quality of surgical recovery. We hypothesized that patients receiving dexamethasone would have a better quality of recovery than patients not receiving dexamethasone. We also sought to compare the effect of perineural with that of IV dexamethasone on block characteristics. METHODS:Patients undergoing elective ankle and foot surgery were recruited over a 9-month period. Patients received ultrasound-guided sciatic nerve blocks by using 0.5% bupivacaine with epinephrine 1:300,000 (0.45 mL/kg) and were randomized into 3 groups: group 1 = perineural dexamethasone 8 mg/2 mL with 50 mL IV normal saline, group 2 = perineural saline/2 mL with IV 8 mg dexamethasone in 50 mL normal saline, and group 3 = perineural saline/2 mL with 50 mL normal saline. The primary outcome was the global score in the quality of recovery (QoR-40). The secondary outcomes included analgesia duration, opioid consumption, patient satisfaction, numeric pain rating scores, and postoperative neurologic symptoms. RESULTS:Eighty patients were randomized, and 78 patients completed the study protocol. There was no improvement in the global QoR-40 score at 24 hours between the perineural dexamethasone and saline, median (97.5% CI) difference of −3 (−7 to 3); IV dexamethasone and saline, median difference of −1 (−8 to 5); or perineural dexamethasone and IV dexamethasone median difference of −2 (−6 to 5). Analgesia duration (P < 0.001) and time to first toe movement (P < 0.001) were prolonged by perineural dexamethasone compared with saline. IV dexamethasone prolonged time to first toe movement compared with saline (P = 0.008) but not analgesia duration (P = 0.18). There was no significant difference in the time to first toe movement or analgesia duration between the perineural and IV dexamethasone groups. Postoperative opioid consumption was not different among study groups. Self-reported neurologic symptoms at 24 hours were not different among perinueral dexamethasone (17, 63%), IV dexamethasone (10, 42%), or normal saline (8, 30%) (P = 0.31). All postoperative neurologic sequelae were resolved by 8 weeks. CONCLUSIONS:Preoperative administration of IV and perineural dexamethasone compared with saline did not improve overall QoR-40 or decrease opioid consumption but did prolong analgesic duration in patients undergoing elective foot and ankle surgery and receiving sciatic nerve block. Given the lack of clinical benefit and the concern of dexamethasone neurotoxicity as demonstrated in animal studies, the practice of perineural dexamethasone administration needs to be further evaluated.

Infragluteal-parabiceps sciatic nerve block: An evaluation of a novel approach using a single-injection technique

Clinical use of the sciatic nerve block (SNB) has been limited by technical difficulties in performing the block using standard approaches, substantial patient discomfort during the procedure, or the need for two injections to block the tibial and peroneal nerves. In this report, we describe a single-injection method for SNB using an infragluteal-parabiceps approach, where the nerve is located along the lateral border of the biceps femoris muscle. SNB was performed in the prone or lateral decubitus position. The needle was positioned (average depth, 56 ± 15 mm) to the point where plantar flexion (53%) or inversion (45%) of the ipsilateral foot was obtained at ≤0.4 mA. Levobupivacaine 0.625% with epinephrine (1:200:000) was administered at a dose of 0.4 mL/kg. The procedure was completed in 6 ± 3 min. Discomfort during block placement was treated with fentanyl 50–100 &mgr;g in 24% of patients. Complete sensory loss and motor paralysis occurred in 92% of subjects at a median time of 10 (range, 5–25) min after injection. Compared with plantar flexion, foot inversion was associated with a more frequent incidence (86% versus 100%), and shorter latency for both sensory loss and motor paralysis of the peroneal, tibial, and sural nerves. There were no immediate or delayed complications. We conclude that the infragluteal-parabiceps approach to SNB is reliable, efficient, safe, and well tolerated by patients.

Nerve stimulator-assisted evoked motor response predicts the latency and success of a single-injection sciatic block.

Variable onset latency of single-injection sciatic nerve block (SNB) may result from drug deposition insufficiently close to all components of the nerve. We hypothesized that this variability is caused by the needle tip position relative to neural components, which is objectified by the type of evoked motor response (EMR) elicited before local anesthetic injection. One-hundred ASA I–II patients undergoing reconstructive ankle surgery received infraglutealparabiceps SNB using 0.4 mL/kg (maximum 35 mL) of levobupivacaine 0.625%. The endpoint for injection was the first elicited EMR: inversion (I), plantar flexion (PF), dorsiflexion (DF), or eversion (E) at 0.2–0.4 mA. The frequencies of the EMRs were: I 40%, PF 43%, E 14%, and DF 3%. SNB was considered complete if both tibial and common peroneal nerves were blocked and failed if either analgesia to pinprick was not observed at 30 min or anesthesia at 60 min. Patients with an EMR of I demonstrated shorter mean times (±95% confidence interval [CI]) to complete the block with 8.5 (95% CI, 6.2–10.8) min compared to 27.0 (95% CI, 20.6–33.4) min after PF (P < 0.001) and 30.4 (95% CI, 24.9–35.8) min after E (P < 0.001). No rescue blocks were required in group I compared with 24% (P = 0.001) and 71% (P < 0.001) of patients in groups PF and E, respectively. We conclude that EMR type during nerve stimulator-assisted single-injection SNB predicts latency and success of complete SNB because the observed EMR is related to the positioning of the needle tip relative to the tibial and common peroneal nerves.

Nerve Block of the Infrapatellar Branch of the Saphenous Nerve in Knee Arthroscopy A Prospective, Double-Blinded, Randomized, Placebo-Controlled Trial

BACKGROUND With the rising use of outpatient knee arthroscopy over the past decade, interest in peripheral nerve blocks during arthroscopy has increased. Femoral nerve blocks are effective but are associated with an inherent risk of the patient falling postoperatively because of quadriceps weakness. We studied blocks of the infrapatellar branch of the saphenous nerve, which produce analgesia in the knee that is similar to that resulting from a femoral nerve block but without associated quadriceps weakness. METHODS Thirty-four patients were enrolled into each arm of this prospective, randomized, double-blinded trial comparing 10 mL of 0.25% bupivacaine used as a block of the infrapatellar branch of the saphenous nerve with a placebo during simple knee arthroscopy. Immediate outcome measures included Numeric Rating Scale (NRS) pain scores (0 to 10 points), mobility and discharge times, opioid usage, subjective adverse side effects, and forty-eight-hour anesthesia recovery surveys. Short-term measures included one-week and twelve-week Lysholm knee scores. RESULTS No adverse effects or increased quadriceps weakness were observed following use of the nerve block. Improvement in early NRS scores and subjective nausea (p = 0.03) were detected. Patients for whom the block was successful also had improved twelve-week Lysholm knee scores (p = 0.04). No differences in opioid usage, mobility time, forty-eight-hour anesthesia recovery scores, or one-week Lysholm knee scores were found. CONCLUSIONS No significant adverse effect or disadvantage was identified for blocks of the infrapatellar branch of the saphenous nerve used in simple knee arthroscopy. In addition to decreased early NRS scores and nausea, blocks of the infrapatellar branch of the saphenous nerve demonstrated potential benefit at twelve weeks after simple knee arthroscopy.

Evaluation of a Proximal Block Site and the Use of Nerve-Stimulator-Guided Needle Placement for Posterior Tibial Nerve Block

BACKGROUND: Posterior tibial nerve (PTN) block has traditionally been performed in the para-medial malleolar area without nerve stimulator (NS) guidance. The PTN can also be blocked proximally (7 cm) above the medial malleolus in the subfascial plane between the flexor hallucis longus and flexor digitorum longus tendons. In this study we compared the frequency of successful PTN block at the traditional distal (D) site (2 cm above the medial malleolus) with and without NS guidance. We also compared block success and latency at the D site versus the proximal (P) block site. METHODS: Subjects were randomized to P-NS (n = 45), D-NS (n = 45), or D without NS (n = 45). Levobupivacaine 0.625%, 0.15 mL/kg was used for all blocks. Pinprick sensory anesthesia was evaluated in the distribution of the medial plantar, lateral plantar, and medial calcaneal nerves. PTN block was considered successful if surgical anesthesia was achieved in all PTN distributions. RESULTS: The frequency of successful PTN block was greater for D-NS (100%) and P-NS (93.5%), compared with D (73.3%) (P = 0.02). Median latency to complete block was less for D-NS (8 min, 95% CI 7-9 min) than D (20 min, 95% CI 13-26 min) (P < 0.01) and P-NS (15 min, 95% CI 12-18 min) (P = 0.04). CONCLUSIONS: NS-guided needle placement improves the success and decreases the latency to onset of complete PTN block at the D site. The P approach to PTN block may be a useful alternative to the traditional D site approach, particularly in patients with restricted access to the D site.

Nerve stimulator-guided supplemental popliteal sciatic nerve block after a failed sciatic block does not increase the incidence of transient postoperative neurologic sequelae.

Background: Supplemental peripheral nerve blocks are not commonly performed in adults because of concerns of cumulative exposure of the nerve to the local anesthetic as well as increased ischemia from epinephrine. The purpose of this study was to compare the incidence of postoperative neurologic symptoms after a failed subgluteal sciatic nerve block and a supplemental popliteal sciatic nerve block. Methods: Five hundred twelve adult patients undergoing ambulatory surgery were prospectively studied (1 yr). Sciatic nerve blocks were performed using levobupivacaine 0.625% with epinephrine 1:200,000 (0.5 ml/kg). Patients who failed to achieve sensory and motor anesthesia at 30–60 min were given a popliteal sciatic nerve block (lidocaine 2% 10 ml + levobupivacaine 0.5% 10 ml). Subjects were contacted at 24 h to 48 h, 2 weeks, and 1 month. Symptomatic patients were contacted biweekly and reevaluated during follow-up surgeon visits until symptom resolution. Results: Four hundred thirty-nine subjects were analyzed. Fifty-six received a popliteal sciatic nerve block. Four subjects (0.9%) had self-reported neurologic symptoms in the distribution of the sciatic nerve. Investigator-initiated follow-up revealed 33 subjects (8.7%) who received a single subgluteal sciatic block and 4 subjects (7.1%) after a supplemental sciatic nerve block with neurologic symptoms (P = 0.80). The median duration of symptoms was 4 weeks (95% CI 3–5) in the subgluteal and 4 weeks (95% CI 3–5) weeks in the popliteal group (P = 0.98). All symptoms resolved by 14 weeks postprocedure. Conclusion: Blocking the sciatic nerve at a more distal site after a failed subgluteal sciatic nerve block does not appear to influence the incidence or duration of neurologic sequelae.

Comparison of laryngeal mask airway insertion methods, including the external larynx lift with pre-inflated cuff, on postoperative pharyngolaryngeal complications: A randomised clinical trial

BACKGROUND Postoperative pharyngolaryngeal complications are commonly reported following laryngeal mask airway (LMA) insertion. After induction of anaesthesia, the airway structures fall backwards under the influence of gravity, and this may contribute to difficulty in placement of a LMA. External airway alignment by lifting the larynx during insertion of an airway may avoid collision of the airway with laryngeal structures. OBJECTIVE(S) To compare pharyngolaryngeal complications after either conventional airway insertion with or without cuff semi-inflation and a method, including an external larynx lift. DESIGN Randomised controlled, double-blind, clinical trial. SETTING Ambulatory surgical operating rooms of a university hospital. PATIENTS American Society of Anaesthesiologists class 1 to 3 patients undergoing ambulatory surgery scheduled to receive general anaesthesia for which a LMA was not contraindicated. INTERVENTIONS Patients were randomised into three groups for LMA placement: G1, deflated airway; G2, pre-inflated cuff; G3, pre-inflated cuff with external lifting of the larynx. Assessment of pharyngolaryngeal complications (blinded assessor) was made at the time of LMA removal and again at 1, 2 and 24 h. MAIN OUTCOME MEASURES A pharyngolaryngeal complication, defined as a composite of one or more of sore throat, dysphonia or dysphagia at any time point, or blood on the airway at removal. RESULTS Of the 450 consecutive patients, 441 were studied. There were no differences in insertion times or number of insertion attempts among the groups. There was no difference in pharyngolaryngeal complications among the groups: G1, 57%; G2, 55%; G3, 52%, (P = 0.77). Blood on the airway was observed less frequently in G3 (9%) compared with G1 and G2 combined (17%): difference −8% (95% confidence interval of the difference −0.8 to −16%, P = 0.01). CONCLUSION The external larynx lift technique was associated with a lower incidence of blood on the airway at removal, suggesting that the method may decrease trauma to the tissues of the upper airway during insertion. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01749033.

Sensory Testing of Distal Sural and Posterior Tibial Nerves Provides Early Prediction of Surgical Anesthesia After Single-Injection Infragluteal-Parabiceps Sciatic Nerve Block

BACKGROUND: Surgical anesthesia for reconstructive ankle surgery requires sensory and motor block of all the terminal nerve distributions of the sciatic nerve. In this prospective observational study, we investigated the value of sensory and motor testing of the foot, after local anesthetic injection, for predicting complete sciatic nerve blockade and the duration of testing required for identifying incomplete anesthesia. METHODS: Sciatic nerve blocks (n = 180) using the infragluteal-parabiceps approach were performed in patients undergoing reconstructive ankle surgery. Levobupivacaine 0.625% with epinephrine 1:300,000 (0.4 mL/kg) was injected after obtaining an elicited motor response at <0.4 mA of plantar flexion or inversion. Pinprick sensory assessments were performed at intervals by an observer unaware of the elicited motor response in the distal cutaneous distributions of the superficial peroneal nerve, deep peroneal nerve, posterior tibial nerve, and sural nerve. Motor block was assessed using foot (plantar flexion and dorsiflexion) movement and toe movement. A complete block was defined as sensory and motor loss in all distributions of the sciatic nerve within 25 minutes of local anesthetic injection. The optimal sensitivity and specificity of various cutoff times of sensory and motor testing were determined by receiver operating characteristic analysis. The area under the curves was compared for equivalence using nonparametric methods. The cutoff times were determined as the point of intersection of the lines of sensitivity and specificity. RESULTS: The elicited evoked motor response before sciatic nerve block was plantar flexion in 87 patients and inversion in 93. Eighty-eight of 93 patients (94.6%) who had an elicited motor response of inversion and 49 of 87 (55.7%) who had an elicited motor response of plantar flexion achieved complete sciatic nerve block at 25 minutes. Area under the curves were not different among testing paradigms. Receiver operating characteristic analysis identified optimal testing times of 4 minutes for the sural and 6 minutes for the posterior tibial nerve with an elicited motor response of inversion and 6 minutes with an elicited motor response of plantar flexion. No subject with an incomplete block achieved sural anesthesia by 10 minutes. CONCLUSION: Sural anesthesia assessed at the lateral heel and the lateral aspect of the foot and the fifth toe identified within 4 to 6 minutes demonstrated a similar posttest predictive value as anesthesia in the distributions of the posterior tibial and peroneal nerves or motor movement of the foot at later intervals. In addition, failure to achieve sural anesthesia within 10 minutes was predictive of block failure.

Ambulatory Anesthesia in an Adult Patient with Corrected Hypoplastic Left Heart Syndrome

With recent advancements in clinical science, an increasing number of patients with congenital heart defects are surviving into adulthood and presenting for noncardiac surgeries. We describe one such example of a 26-year-old patient with corrected hypoplastic left heart syndrome presenting for knee arthroscopy and performed under general anesthesia with preoperative ultrasound guided saphenous nerve block. In this case, we review the anesthetic implications of corrected single ventricle physiology, anesthetic implications, as well as discuss the technique and role of saphenous nerve block in patients undergoing knee arthroscopy.