Pacemaker leads

Present day pacemaker leads are far superior in every respect to those of the past. Modification of fixation characteristics has reduced displacement rates to 1% or less in most centers. Fracture of multifilar leads is a rarity. Biodegradation of polyurethane insulation appears to be an isolated problem specific to individual lead models and may be related to physical stresses incurred during manufacture or lead insertion. Recent evidence has incriminated an interaction of polyurethane with silver which arises from the drawn braised strand conductor substrate of those leads in which this problem has been noted. This may explain why the problem has been restricted to specific lead models of one manufacturer to date. Lack of uniformity of lead terminal size between manufacturers and even within the same manufacturer's product line continues to baffle this observer. Although past problems of lead displacement have been markedly reduced, the difficulty of removing chronic leads which have become septic appears to have worsened. Modification of existing leads to ensure that the interface between electrode tip and proximal shaft is unidiametric is essential.     

Safety and efficacy of transvenous lead extraction of very old leads

OBJECTIVESTransvenous lead extraction using mechanical rotational- or laser sheaths is an established procedure. Lead dwell time has been recognized as a risk factor for extraction failure and procedure-related complications. We therefore investigated the safety and efficacy of transvenous extraction of leads with an implant duration of more than 10 years.Open in a separate windowMETHODSBetween January 2013 and March 2017, a total of 403 patients underwent lead extraction in 2 high-volume lead extraction centres. One hundred and fifty-four patients with extraction of at least 1 lead aged over 10 years were included in this analysis. Laser lead extraction was the primary extraction method, with additional use of mechanical rotational sheaths or femoral snares, if necessary. All procedural- and patient-based data were collected into a database and retrospectively analysed.RESULTSMean patient’s age was 65.8 ± 15.8 years, 68.2% were male. Three hundred and sixty-two leads had to be extracted. The mean lead dwell time of treated leads was 14.0 ± 6.1 years. Complete procedural success was achieved in 91.6% of cases, while clinical success was achieved in 96.8%. Failure of extraction occurred in 3.2%. Leads that could not be completely removed had a significantly longer lead dwell time (18.2 vs 13.2 years; P = 0.016). Additional mechanical rotational sheaths or femoral snares were used in 26 (16.9%) patients. Overall complication rate was 4.6%, including 5 (3.3%) major and 2 (1.3%) minor complications. There was no procedure-related mortality.CONCLUSIONSTransvenous lead extraction in leads aged over 10 years is safe and effective when performed in specialized centres and with use of multiple tools and techniques. Leads that could not be completely extracted had a statistically significant longer lead dwell time.     

The optimal usage of the ISCP by trainee and trainer

The Intercollegiate Surgical Curriculum Programme (ISCP) provides the Curriculum with the specialty syllabus, trainee’s portfolio of activity, and the process and recording of assessment. It is an excellent resource and in order to gain the optimal benefit trainees and trainers are recommended to invest some time in navigating through the site and understand its functionality. The launch of the 2021 Surgical Curricula is an important change with the new assessment tool of the Multiple Consultant Report (MCR) and the trainee input with their self-assessment. The ISCP has incorporated the MCR assessment process (Generic Professional Capabilities and Capabilities in Practice) into the learning agreement structure such that the progression through to the higher-level outcome of the curriculum, defined as a day 1 consultant in a specialty, is enhanced by frequent and focussed feedback specific to the trainee. To achieve the optimal outcomes, it is important to have strong engagement with the ISCP and the useability has been enhanced to facilitate this.     

Tremor and Quality of Life in Patients With Advanced Essential Tremor Before and After Replacing Their Standard Deep Brain Stimulation With a Directional System

ObjectivesPatients with essential tremor treated with thalamic deep brain stimulation may experience increased tremor with the progression of their disease. Initially, this can be counteracted with increased stimulation. Eventually, this may cause unwanted side-effects as the circumferential stimulation from a standard ring contact spreads into adjacent regions. Directional leads may offer a solution to this clinical problem. We aimed to compare the ability of a standard and a directional system to reduce tremor without side-effects and to improve the quality of life for patients with advanced essential tremor.Materials and MethodsSix advanced essential tremor patients with bilateral thalamic deep brain stimulation had their standard system replaced with a directional system. Tremor rating scale scores were prospectively evaluated before and after the replacement surgery. Secondary analyses of quality of life related to tremor, voice, and general health were assessed.ResultsThere was a significantly greater reduction in tremor without side-effects (p = 0.017) when using the directional system. There were improvements in tremor (p = 0.031) and voice (p = 0.037) related quality of life but not in general health for patients using optimized stimulation settings with the directional system compared to the standard system.ConclusionsIn this cohort of advanced essential tremor patients who no longer had ideal tremor reduction with a standard system, replacing their deep brain stimulation with a directional system significantly improved their tremor and quality of life. Up-front implantation of directional deep brain stimulation leads may provide better tremor control in those patients who progress at a later time point.     

Dangerous single lead ST elevation

Discriminating among the various coronary obstruction patterns influences early management decisions. One of the most important tasks is the identification of ST-elevation myocardial infarction caused by left main occlusion. We present a case of single-lead ST-segment elevation in aVR caused by acute left main coronary artery occlusion.     

The Prospective Evaluation of Safety and Success of a New Method of Introducing Percutaneous Paddle Leads and Complex Arrays With an Epidural Access System

Objectives: Spinal cord stimulation (SCS) has become a mainstay in the continuum of care for patients suffering from chronic neuropathic pain of the trunk and limbs. Options for placing these devices have included a percutaneous method of using an epidural needle to place a cylindrical (percutaneous) lead to stimulate the spinal cord, or an open laminotomy method for placing a paddle lead at the location of the surgical decompression of the laminae. Both of these methods have been successful in a high percentage of patients, but neither have been ideal. Limitations of the percutaneous leads have been inefficiency of power delivery, inability to achieve desired depth of stimulation in the spinal cord, occasional lead migration and difficulty covering complex pain patterns. Limitations of the paddle lead have been the need for surgical laminotomy, inability to steer the lead once placed, limits on placement in the vicinity of the surgical decompression, and a perceived risk of increased bleeding and trauma to the tissue. These factors have led many minimally invasive spine specialists to seek new options for SCS. This paper presents the initial US experience with a newly approved device to place both paddle leads, and multi‐lead arrays into the epidural space via a percutaneous Seldinger‐guided approach through a single needle placement. We will both describe the technique and review the outcomes of some of the early cases. Materials and Methods: After Investigational Review Board clearance, patients consented to data collection in a prospective fashion regarding the use of a new percutaneous epidural introducer (Epiducer, St. Jude Neurological, Minneapolis, MN, USA) to place paddle leads and complex lead arrays. The patients underwent education regarding expectations and risks of the procedure consistent with our normal preoperative period. Patients underwent preoperative anesthesia screening and proper testing as outlined by the Joint Commission on Hospital Accreditation, and were given the opportunity to ask questions concerning the procedure. Once the patient wished to move forward, they were consented using the approved case reporting form and followed during the course of their care. The initial cases were performed in West Virginia with subsequent cases following at the other centers involved in this analysis. The outcomes of this analysis focused on three areas:

• 1 The technical success in placing the percutaneous sheath. This included the ability to successfully complete:
  • ? epidural access with a 14‐gauge Tuohy needle
  • ? ability to place a styleted guidewire
  • ? ability to introduce the introduction system over the wire into the epidural space
  • ? ability to remove the guidewire and introduction tip leaving the 10‐gauge sheath intact
• 2 The ability to place the desired lead or leads into the epidural space via the percutaneous introduction sheath.
• 3 The presence of any major adverse event which were defined as:
  • ? nerve injury
  • ? paraplegia
  • ? worsening of baseline pain
  • ? epidural hematoma
  • ? epidural infection
  • ? dural tear
  • ? dural rent
  • ? retained device that could not be removed

This information was carefully recorded for each implant, and summarized in this communication. Results: During the initial 30 days of the evaluation period, 43 epidural introduction systems were attempted in 38 patients. In patients in whom more than one paddle lead was placed, the system required the reinsertion of the guidewire through the Epiducer, removal of the Epiducer, and rewiring over the guidewire. This is necessary because the diameter of a paddle lead does not allow two or three leads to be placed without rewiring the system. The success of placement was 42/43, with inability to access the epidural space in one patient in whom ligamentum flavum hypertrophy was present on the preoperative imaging study. In all patients, the system was placed at the L1–L2 level, or lower, based on the Food and Drug Administration labeling. The total numbers of leads placed were 75, with both paddle and percutaneous arrays implanted successfully. There were no adverse events during this prospective surveillance evaluation. Ten patients complained of soreness at the entry site and post‐procedure stiffness. These complaints were treated with ice, rest, and analgesics and resolved without incident. Conclusion: This paper describes the initial US cases of the placement of a paddle lead via a minimally invasive percutaneous method, as well as complex cylindrical arrays with a single needle entry to the epidural space. The device functioned successfully and presented a safe option for placing paddle leads and complex arrays.     

A New Technique of “Midline Anchoring” in Spinal Cord Stimulation Dramatically Reduces Lead Migration

Spinal cord stimulation (SCS) is a popular method of treatment of chronic pain. Unfortunately, migration of the lead continues to be a serious complication of this therapy. In an attempt to reduce lateral migration of the SCS lead, we performed a retrospective assessment of a new technique of percutaneous lead placement. This new method of “midline anchoring” of the lead using the plica mediana dorsalis was tested against conventional technique in a retrospective study involving 122 trials and 91 implants of SCS over a period of five years. The use of “midline anchoring” resulted in a decrease in lead migration from 23% to 6% after trial insertion and from 24% to 7% after implantation. We conclude that “midline anchoring” of the SCS lead is an effective method of preventing lead migration.     

滇黄芩地上部分化学成分的分离鉴定

目的:研究滇黄芩(Scutellaria amoena)地上部分的化学成分。方法:采用90%乙醇加热回流提取滇黄芩地上部分,所得浸膏用水悬浮后用乙酸乙酯和正丁醇萃取分为不同极性部位。继而通过硅胶柱色谱,LH-20羟丙基葡聚糖凝胶(Sephadex LH-20)柱色谱及重结晶等方法分离纯化,根据化合物的理化性质和波谱数据(MS,~1H-NMR,~(13)C-NMR)鉴定化学结构。结果:从滇黄芩地上部分的90%乙醇提取物中分离得到11个化合物,分别鉴定为黄芩素(1),黄芩苷(2),千层纸素A(3),千层纸素A-7-O-β-D-吡喃葡萄糖醛酸苷(4),汉黄芩素(5),去甲汉黄芩素(6),白杨素(7),白杨素-7-O-β-D-吡喃葡萄糖醛酸苷(8),野黄芩苷(9),5,7-二羟基-6,8-二甲氧基黄酮(10),β-谷甾醇(11)。结论:以上化合物均为首次从该种植物的地上部分中分离得到,化合物9,10为首次从该种植物中分离得到。     

荔枝草的化痰、止咳、抗炎药效学的研究

采用小鼠呼吸道酚红冲洗法、大鼠毛细玻管法、氨水引咳法、小鼠腹腔毛细血管通透实验观察了荔枝草的化痰、镇咳、抗炎作用。结果表明荔枝草能显著增加小鼠呼吸道黏膜酚红的排出量,增加大鼠呼吸道内痰液的分泌量,可明显延长引咳潜伏期,减少咳嗽次数,对小鼠醋酸造成的炎症模型也具有抗炎作用。该实验结果为临床上合理科学使用荔枝草作为药物进行疾病的治疗有指导意义。