Occipital Nerve Stimulator Lead Pathway Length Changes with Volunteer Movement: An In Vitro Study

Background:   Occipital nerve stimulation is a modality reserved for refractory headache disorders. Leads (wires) are inserted subcutaneously in the occipital region to stimulate the distal C1-3 nerves; lead migration may result from repeated mechanical forces on the lead associated with patient movement. The primary aim of this study was to determine implantation pathways associated with the least pathway length change secondary to body movement in an in vitro model of an occipital stimulator system.
Methods:   After institutional review board approval, 10 volunteers were recruited. The expected pathway of an occipital stimulator system was identified and measured externally, and then changes in pathway length were measured during various volunteer movements, including neck and low back flexion, extension, rotation, and lateral flexion. The pathways studied included those that connect internal pulse generators in the gluteal, low abdominal, and infraclavicular regions to occipital leads inserted via a cervical or retromastoid approach.
Results:   The flexion/extension pathway length changes associated with midline occipital and retromastoid sites to the infraclavicular site were significantly less than those pathways to the periscapular site. Also, the abdominal site was associated with less pathway length change during flexion/extension than the gluteal site.
Conclusions:   Internal pulse generators in sites other than the buttock, including infraclavicular or low abdomen, may be associated with lower lead migration risk.
There are many considerations when selecting insertion sites and lead pathways for occipital nerve stimulation. Implanters and patients may consider these results when contemplating surgical approaches to this challenging form of peripheral nerve stimulation.     

神经刺激器引导用于臂丛神经阻滞及术后镇痛研究

目的 观察神经刺激器定位下经斜角肌间沟留置导管用于持续臂丛神经阻滞及术后镇痛的临床效果和可行性。方法 ASAⅠ～Ⅱ级上肢手术患者60例。随机分为套管针组（A组）和留置导管组（B组），每组30例。A组患者用20G静脉穿刺套管针行常规方法臂丛神经阻滞留置，B组患者在周围神经刺激器引导下穿刺置入专用的柔软导管，手术结束后两组患者均连接一电子镇痛泵行持续术后臂丛神经阻滞镇痛。结果 术中需辅助用药患者两组无统计学差异（P〉0．05）。A组患者术后镇痛失败率达23．3％，B组无镇痛失败患者，两组比较差异有显著性（P〈0．05）。剔除A组镇痛失败患者后，两组患者术后48h内的VAS评分、Ramsay评分和PCA按压次数无统计学差异（P〉0．05）。结论 周围神经刺激器精确引导下经斜角肌间沟留置导管行臂丛神经阻滞和持续术后镇痛是一种可行性好、镇痛效果确切、不良反应少的方法。     

Feasibility of an infraclavicular block with a reduced volume of lidocaine with sonographic guidance.

OBJECTIVE: A successful brachial plexus block requires a large volume of a local anesthetic. Sonography allows reliable deposition of the anesthetic around the cords of the brachial plexus, potentially lowering the anesthetic requirement. METHODS: Fifteen sonographically guided infraclavicular blocks were performed in 14 patients with 2% carbonated lidocaine with epinephrine through a 17-gauge Tuohy needle. The amount of lidocaine injected at several points around each cord was based on satisfactory spread observed sonographically. A 19-gauge catheter was then placed with its tip between the posterior cord and axillary artery, and tip position was confirmed by observing the spread of 1 to 2 mL of injected air. Lidocaine was injected through the catheter if necessary to prolong the blocks. RESULTS: Surgery was performed in all patients without general anesthesia, rescue blocks, or infiltration. A heroin user was given an additional 50 microg of fentanyl before the block. One patient required 5 mL of lidocaine through the catheter for an incomplete radial nerve block 5 minutes after initial injection. Seven patients received additional midazolam (mean, 2.5 mg) for alleviation of anxiety despite excellent blocks. The mean +/- SD volume of lidocaine for the initial block was 16.1 +/- 1.9 mL (4.2 +/- 0.9 mg/kg). In 4 patients, additional lidocaine 1 hour after an initial successful block increased the total volume to 19.5 +/- 7.1 mL (5 +/- 1.9 mg/kg). The mean times to perform the block, onset of the block, and achieving surgical anesthesia and the duration of surgery were 10.8 +/- 3.3, 2 +/- 1.3, 5.9 +/- 2.6, and 92.7 +/- 54.4 minutes, respectively. CONCLUSIONS: A successful infraclavicular block in adults with 14 mL of lidocaine is feasible with the use of sonography. The reduced volume does not seem to affect the onset but shortens the duration of the block.     

高频超声对臂丛神经显像和定位的价值

目的评价高频超声对臂丛神经显像和定位的价值。方法采用高频超声对30例志愿者行臂丛神经检查，主要在肌间沟、锁骨上、锁骨下及腋下4个部位。11例志愿者臂丛分布的4个部位上，在实时超声引导下进针及定位神经，然后在电神经器刺激下确认是否为神经。所有臂丛神经声像图特征、解剖的变化、进针和神经定位均被动态记录。结果臂丛神经在横断面上表现为圆形或椭圆形的低回声结构，内部由点状回声组成，肌间沟、锁骨上及腋下臂丛神经显示率均为100％，锁骨下臂丛神经显示率为97％。11例志愿者臂丛声像图上低回声结构在超声引导下行电刺激均被证实为神经组织。结论高频超声能提供高质量的臂丛神经声像图。超声引导下穿刺对臂丛神经阻滞麻醉有潜在应用价值。     

Surface Stimulation to Determine Needle Direction and Angle When Performing an Infraclavicular Brachial Plexus Block

Abstract:   The infraclavicular approach to the brachial plexus is a safe and reliable technique for surgery of the upper extremity. When performing the block, the anesthesiologist must appreciate three variables: needle direction, needle angle to the chest wall, and needle depth. Surface stimulation is an easy technique that can reliably predict both needle direction and needle angle.     

Peripheral nerve stimulator for the treatment of supraorbital neuralgia: a retrospective case series

Peripheral nerve blocks of the supraorbital, supratrochlear or occipital nerve have been utilized for the relief of headaches, although relief may be short-lasting. The purpose of this study was to evaluate the efficacy of supraorbital nerve stimulation for treatment of intractable supraorbital neuralgia. Patients presenting to the pain clinic with refractory frontal headaches who responded to a diagnostic supraorbital nerve block were selected for this case series. Patients underwent a trial of supraorbital nerve stimulation, and efficacy was assessed after 5–7 days ( n  = 16). From the trial, 10 patients consented to undergo permanent implantation of the stimulator. Opioid consumption and headache scores were monitored preoperatively and at timed intervals for 30 weeks. Headache scores decreased, and opioid consumption was reduced in half, and these beneficial accomplishments were maintained up to 30 weeks after implantation. In selected patients, supraorbital nerve stimulation for the treatment of chronic frontal headaches appears to be efficacious.     

Permanent upper trunk plexopathy after interscalene brachial plexus block

Interscalene brachial plexus block (IBPB) has been widely used in shoulder surgical procedures. The incidence of postoperative neural injury has been estimated to be as high as 3 %. We report a long-term neurologic deficit after a nerve stimulator assisted brachial plexus block. A 55 year-old male, with right shoulder impingement syndrome was scheduled for elective surgery. The patient was given an oral dose of 10 mg of diazepam prior to the nerve stimulator assisted brachial plexus block. The patient immediately complained, as soon as the needle was placed in the interscalene area, of a sharp pain in his right arm and he was sedated further. Twenty-four hours later, the patient complained of severe shoulder and arm pain that required an increased dose of analgesics. Severe peri-scapular atrophy developed over the following days. Electromyography studies revealed an upper trunk plexus injury with severe denervation of the supraspinatus, infraspinatus and deltoid muscles together with a moderate denervation of the biceps brachii muscle. Chest X-rays showed a diaphragmatic palsy which was not present post operatively. Pulmonary function tests were also affected. Phrenic nerve paralysis was still present 18 months after the block as was dysfunction of the brachial plexus resulting in an inability to perform flexion, abduction and external rotation of the right shoulder. Severe brachial plexopathy was probably due to a local anesthetic having been administrated through the perineurium and into the nerve fascicles. Severe brachial plexopathy is an uncommon but catastrophic complication of IBPB. We propose a clinical algorithm using ultrasound guidance during nerve blocks as a safer technique of regional anesthesia.     

Single needle approach for multiple medial branch blocks: a new technique

BACKGROUND AND OBJECTIVES: Medial branch blocks are an important tool for the diagnosis of facet joint arthropathy. The most commonly used technique involves multiple needle placements, one for each nerve blocked. This multiple needle technique may require a large amount of local anesthetic for anesthetizing the skin, thereby increasing the rate of false-positive blocks. TECHNIQUE: Diagnostic lumbar medial branch blocks are usually performed using multiple needles, one for each branch. The authors describe a different technique using a single needle for all levels. Initially, the needle is directed toward the medial branch located at the level of the affected facet joint in the antero-posterior view. After anesthetizing this nerve with local anesthetic, the same needle is withdrawn to the skin with the tip still in the subcutaneous tissue and repositioned to block the medial branch above, and thereafter below, while continuing to use only the antero-posterior view, thereby using only one entry site. CONCLUSIONS: When performed correctly, the single needle technique provides accuracy similar to the more conventional multiple needle approach during the performance of diagnostic facet joint nerve blocks. Because only one skin entry point is needed, however, this technique may afford several advantages over the multiple needle approach. These may include less patient discomfort, less time required and less radiation exposure since only one C-arm position is used, a smaller volume of local anesthetic, and possibly a lower incidence of false-positive blocks.     

Ultrasound-Guided Lumbar Plexus Block for Open Reduction and Internal Fixation of Hip Fracture

Purpose: Ultrasound technology has been applied to increase both efficacy and safety of certain peripheral nerve blocks. This case report describes the first successful ultrasound‐guided lumber plexus block. Clinical Features: We describe a 91‐year‐old woman with aortic stenosis who successfully underwent open reduction and internal fixation of a fractured right hip with a lumbar plexus block. Ultrasound provided direct visualization to help identify the anatomical structures and guide the block needle during performance of the block. Complete block of the lumbar plexus was attained within 15 min, and the surgical procedure was performed uneventfully. Conclusion: The use of ultrasound has gained popularity to perform peripheral nerve blocks. In this case report, a successful lumbar plexus block was performed with ultrasound guidance. By direct visualization, using this technology may potentially reduce complications associated with lumbar plexus blocks.     

Brachial plexus anesthesia for outpatient surgical procedures on an upper extremity

We retrospectively reviewed 543 brachial plexus blocks performed on 526 outpatients. Most (98%) of the blocks were performed by means of the axillary approach. Various techniques were used, including paresthesia, transarterial fixation, nerve stimulation, or a combination of techniques; a high success rate was achieved with each of them. Only 7% of the blocks were incomplete and thus necessitated either general anesthesia or block supplementation with thiopental sodium and nitrous oxide. No persistent neurologic deficit was ascribed to the anesthetic technique. This review indicates that brachial plexus block, especially with use of the axillary approach, is a safe and effective option for outpatient surgical procedures on an upper extremity.     

Anesthesia (8)

The effects of the single or multiple injection technique on the onset time of femoral nerve blocks with 0.75% ropivacaine. (University of Milan and IRCCS San Raffaele Hospital, Milan, Italy) Anesth Analg 2000;91:181–184. This study evaluated the effect of the injection technique on the onset time and efficacy of femoral nerve block performed with 0.75% ropivacaine. A total of 30 patients undergoing arthroscopic knee surgery were randomly allocated to receive femoral nerve blocakade with 0.75% ropivacaine by using either a single injection (Single group, n = 15) or multiple injection (Multiple group, n = 15). Nerve blocks were placed by using a short‐beveled, Teflon‐coated, stimulating needle. The stimulation frequency was set at 2 Hz, and the intensity of the stimulating current, initially set at 1 mA, was gradually decreased to <0.5 mA after each muscular twitch was observed. In the Single group, 12 mL of 0.75% ropivacaine was slowly injected, as soon as the first muscular twitch was observed. In the Multiple group, the stimulating needle was inserted and redirected, eliciting each of the following muscular twitches: contraction of vastus medialis, vastus intermedius, and vastus lateralis. At each muscular twitch, 4 mL of the study solution was injected. Placing the block required 4.2 ± 1.7 min in the Multiple group and 3.4 ± 2.2 min in the Single group (P = 0.02). Onset of nerve block required 10 ± 3.7 min in the Multiple group and 30 ± 11 min in the Single group (P < 0.0005). Propofol sedation was never required to complete surgery; although 0.1 mg fentanyl at trocar insertion was required in 2 patients of the Multiple group (13%) and 9 patients of the Single group (60%) (P = 0.02). Conclude that searching for multiple muscular twitches shortened the onset time and improved the quality of femoral nerve block performed with small volumes of 0.75% ropivacaine. Comment by Octavio Calvillo, MD, PhD. This study is concerned with the onset of femoral nerve block utilizing 0.75% ropivacaine in 2 groups of 15 patients undergoing arthroscopic knee surgery. The optimal site for injection was identified by the electrically evoked muscular twitch at the quadriceps. In 1 group, 12 mL of 0.75% ropivacaine was injected as soon as a muscle twitch was evoked. In the second group, 4 mL of local anesthetic was injected only after a specific response was elicited at the vastus medialis, vastus intermedius, and vastus laterallis. Onset of the nerve block required 10 ± 3.7 min. in the multiple injection group, whereas in the single group, onset of the nerve block took 30 ± 11 min. The authors concluded that searching for multiple twitches shortened the surgical anesthesia and improved the quality of neural blockade.     

外周神经刺激器定位腰丛-坐骨神经阻滞在血管外科下肢手术中的应用

目的观察外周神经刺激器定位下的腰丛-坐骨神经阻滞应用于血管外科患者下肢手术的效果。方法20例血管外科拟行单侧下肢手术的患者,施行单侧腰丛-坐骨神经阻滞。腰丛阻滞为腰肌间隙入路,坐骨神经阻滞为臀区入路。采用神经刺激器定位技术,刺激器电流频率1 Hz,起始强度1 mA,麻醉总量为1%利多卡因30 mL、0.5%罗哌卡因30 mL。结果20例患者均阻滞完善,麻醉效果满意,术中生命体征平稳,血流动力学稳定。结论神经刺激器定位技术下腰丛-坐骨神经阻滞定位准确,客观指征明显,效果可靠,对患者各系统干扰小,对有严重合并症患者更为适用。     

Skin electrical resistance does not change following infraclavicular block

Peripheral nerve blocks are common and effective means for anesthesia for limb surgery. The evaluation of the success of a peripheral blockade is based on the loss of sensation, with no objective means of detecting a successful block. The autonomic innervation to the upper extremity, which controls both the vascular tone and the activity of sweat glands, is supplied by nerve fibers accompanying the somatic nerve fibers. Previous studies have shown changes in both skin temperature and electrical resistance of the skin following brachial plexus block. We studied 20 patients undergoing hand surgery under infraclavicular brachial plexus block. The electrical resistance of the skin on the palmar aspect of the forearm was continuously recorded on the block arm and on the contralateral arm using a commercial skin resistance monitor. No statistically significant change in the electrical resistance of the skin was observed during 20 minutes after placement of the block. These results strongly suggest that the electrical resistance of the skin cannot be used to predict a successful infraclavicular block.     

神经阻滞的注射针定位中电刺激强度与针尖-神经干距离及针尖斜面方向关系的实验研究

目的：探讨神经阻滞注射针定位技术的针尖-胫神经干距离与刺激电流强度关系,为神经阻滞技术的临床应用提供理论依据。方法：新西兰大白兔7只,体重2.5±0.5kg,雌雄不限。兔大腿后外侧纵向切口暴露胫神经干14条,以三维定位仪定位针尖与神经干间距离,分别于针尖-神经干距离为0mm、1mm、2mm、3mm、4mm、5mm处调节刺激器电流（直流电方波输出,波宽0.2ms,频率2Hz）强度,记录诱导靶肌肉收缩的最低刺激电流。结果：最低电流刺激强度分别为：0.28±0.07mA（0mm）、0.34±0.08mA（1mm）、0.44±0.10mA（2mm）、0.58±0.15mA（3mm）、0.74±0.17mA（4mm）、0.91±0.21mA（5mm）。以针尖-神经干距离为自变量X,最低电刺激强度均数为应变量Y,直线回归分析示两者间存在线性回归关系,方程为Y=0.13X+0.22, 决定系数r2=0.974。结论：注射针定位中针尖-神经干距离与刺激电流强度呈线性回归关系,对临床神经阻滞中的注射针定位有指导意义。     

Peripheral nerve blocks: understanding the nurse's role.

This article describes the nursing care and management of patients during and after administration of peripheral nerve blocks. We review recommendations for patient monitoring, as well as the risks and complications associated with anesthetic agents. Several upper and lower extremity blocks, including the Bier block, are described. The nursing role in the use of the peripheral nerve stimulator is also explained. Throughout the discussion, nursing responsibilities are emphasized.     

Nerve stimulator‐assisted femoral nerve block in the emergency department

Objective : To describe the technique of femoral nerve block using a nerve stimulator to locate the nerve, and to report the success rate of its use by junior and senior doctors in the emergency department. Method : Standardized protocol and patient selection criteria were formulated for the performance of femoral nerve block on patients with femoral neck or shaft fractures using a nerve stimulator to locate the femoral nerve and confirm deposition of local anaesthetic agent close to the femoral nerve. Femoral nerve blockade was assessed before and after femoral nerve block by testing for altered sensation in the cutaneous distribution of the femoral nerve. Pain was assessed before and after femoral nerve block using a visual analogue scale. The use of supplementary analgesics was recorded. Results : A successful femoral nerve block was obtained with the nerve stimulator in 19 of 22 attempts (86%) at femoral nerve block. Success was unrelated to seniority of staff. Femoral nerve block was the only analgesia required in 17 patients (77%). Femoral nerve block was the only analgesia required for 100% for femoral shaft fractures and 75% and 73%, respectively, for extra‐capsular and intracapsular fractures of the femoral neck. Conclusion : The femoral nerve was accurately located using the nerve stimulator irrespective of seniority of staff performing the procedure. Femoral nerve block using the nerve stimulator was effective analgesia for femoral shaft fractures and the majority of both intra‐ and extra‐capsular femoral neck fractures.     

Continuous peripheral nerve block for ambulatory surgery. (Duke University, Durham, NC) Reg Anesth Pain Med 2001;26:209–214.

In this study data was prospectively gathered for 1 year from 228 patients in an ambulatory surgery center. All continuous peripheral nerve blocks (CPNB) were performed using the Contiplex system to provide anesthesia and postoperative analgesia. CPNB were performed using 5 upper and lower extremity techniques. Postsurgery local anesthetic was infused and at 24 hours, a rebolus of local anesthetic was performed. The CPNB catheter was removed and patients were examined for a loss of sensation. Patients were then discharged. The initial peripheral block was successful in 94% of the patients. Failed nerve block requiring general anesthesia occurred in 6%. The catheter was patent and functional in 90% of the patients at 24 hours, and 8% of the patients required more than 10 mg of intravenous morphine by 24 hours postsurgery. In the postanesthesia care unit, only 4 patients (1.7%) required treatment for nausea. At 24 hours and 7 days postsurgery, no patient reported a dysesthesia. Conclude that CPNB using the insulated Tuohy catheter system offered acceptable anesthesia and prolonged pain relief postsurgery. There were few side effects. Comment by Alan David Kaye, M.D., Ph.D., Erin Bayer, M.D. This study demonstrates the efficacy of the Contiplex system (CPNB) in providing surgical anesthesia and postoperative analgesia through CPNB. Despite the efficacy of CPNB, which could provide longer duration of postoperative analgesia than single injection block, it is not widely used due to lack of available equipment. Contiplex system utilizes a connector for a nerve stimulator attached to a 18‐gauge Tuohy needle. It allows for aspiration of blood, injection of local anesthesia and passage of a peripheral nerve catheter. This study demonstrated in an ambulatory surgery center with 228 patients, CPNB was used for 27 different types of surgical procedures which involved 5 different block sites. Success rates were 94% for initial peripheral block while 6% required general anesthesia. Patients required less postoperative analgesia. The incidence of postoperative side effects such as nausea and vomiting were minimal. Not a single patient reported dissatisfied with a 7‐day telephone follow‐up. A disadvantage of this technique is the use of an 18‐gauge needle and potential for vascular and/or nerve injuries, which did not occur in this study. Though previous studies have demonstrated the efficacy of the CPNB in inpatients, this is an important study focused on outpatients. A larger study group will be valuable in future studies.     

Usefulness of perfusion index to detect the effect of brachial plexus block

The traditional method to evaluate adequacy of the block for surgery is based on loss of sensory response to stimuli, which requires patient cooperation. Several methods have been described for objective assessment of the nerve block. The aim of the study was to investigate whether perfusion index (PI), a measure of peripheral perfusion from a pulse oximetry finger sensor, is a reliable and objective method for assessing the adequacy of infraclavicular blockade and to describe the time course of PI changes once peripheral nerve block has been achieved during surgery. The study was performed on patients scheduled for elective hand, wrist and forearm surgery under infraclavicular brachial plexus block. The pulse oximetry sensor was affixed to a finger ipsilateral to the side of the infraclavicular block for continuous measurement of PI. The average PI and the average percent change in PI from baseline, at 10, 20 and 30 min from the administration of the block were calculated. Baseline values of PI ranged from 0.6 to 4.7 % in 44 patients for whom infraclavicular block was effective and 1.8 to 2.4 % in 2 patients for whom infraclavicular block failed. Differences were not significant (p = 0.60). In the effective infraclavicular block group, PI rose continuously during the 30-min observation period. At 10 min, PI increased by (mean ± standard deviation) 120 ± 119 % from baseline. At 20 and 30 min, perfusion index increased by 133 ± 125 % and 155 ± 144 % from baseline. All changes from baseline were significant (p < 0.01). The perfusion index is a predictor of infraclavicular block success. The largest changes in PI occur 30 min after the block administration but significant changes in PI were detected 10 min after administration. Perfusion index monitoring may provide a highly valuable tool to quickly evaluate the success of regional anesthesia of the upper extremity in clinical practice.     

Sonographically guided infraclavicular brachial plexus block in adults: a retrospective analysis of 1146 cases.

OBJECTIVE: The aim of this study was to analyze our experience in 1146 cases of sonographically guided infraclavicular brachial plexus block (ICBPB) performed over 32 months. METHODS: Anesthetic records of 1146 cases of sonographically guided ICBPB performed by our staff were studied retrospectively with the use of a database created by an automated anesthesia record-keeping system. The rates of successful blocks, failed blocks necessitating conversion to general anesthesia or requiring supplementation with local anesthetics, those requiring larger-than-usual doses of sedation, and complications were determined. Analysis included an attempt to determine the possible causes of inadequate blocks and complications. RESULTS: In 1138 patients (99.3%), the block was successful. Six patients had incomplete blocks requiring general anesthesia, and another 2 patients needed local anesthetic supplementation by the surgeons. Ninety-seven percent of the blocks were performed by residents directly supervised by an attending anesthesiologist who held the ultrasound probe. The mean age+/-SD of the patients was 39+/-15 years; the mean duration of surgery was 165+/-114 minutes; and the male-female ratio was 4:1. More than 50% of patients were obese. There were no reported cases of nerve injury, pneumothorax, or local anesthetic toxicity. Arterial punctures occurred in 8 (0.7%) patients, but all were inconsequential. CONCLUSIONS: The data from this retrospective study suggest that sonographic guidance provides a high success rate (99.3%) and improved safety for ICBPB. The increased operator team experience virtually eliminates failure and complications.     

Botulinum Toxin Occipital Nerve Block for the Treatment of Severe Occipital Neuralgia: A Case Series

▪ Abstract:   Persistent occipital neuralgia can produce severe headaches that are difficult to control by conservative or surgical approaches. We retrospectively describe a series of six patients with severe occipital neuralgia who received conservative and interventional therapies, including oral antidepressants, membrane stabilizers, opioids, and traditional occipital nerve blocks without significant relief. This group then underwent occipital nerve blocks using the botulinum toxin type A (BoNT-A) BOTOX® Type A (Allergan, Inc., Irvine, CA, U.S.A.) 50 U for each block (100 U if bilateral). Significant decreases in pain Visual Analog Scale (VAS) scores and improvement in Pain Disability Index (PDI) were observed at four weeks follow-up in five out of six patients following BoNT-A occipital nerve block. The mean VAS score changed from 8 ± 1.8 (median score of 8.5) to 2 ± 2.7 (median score of 1), while PDI improved from 51.5 ± 17.6 (median 56) to 19.5 ± 21 (median 17.5) and the duration of the pain relief increased to an average of 16.3 ± 3.2 weeks (median 16) from an average of 1.9 ± 0.5 weeks (median 2) compared to diagnostic 0.5% bupivacaine block. Following block resolution, the average pain scores and PDI returned to similar levels as before BoNT-A block. In conclusion, BoNT-A occipital nerve blocks provided a much longer duration of analgesia than diagnostic local anesthetics. The functional capacity improvement measured by PDI was profound enough in the majority of the patients to allow patients to resume their regular daily activities for a period of time. ▪