The Neuromodulation Casebook

Jeffrey Arle

• Publisher: Academic Press
• Year: 2020
• ISBN:
  9780128170038
• Topic: Biological Sciences
• Subtopic: Neuroscience
• Index: Biological Sciences

The Neuromodulation Casebook is a case-based volume for practical, hands-on decision-making using realistic case examples from the field of neuromodulation. It encompasses a variety of techniques and therapies, ranging from deep brain stimulation for a multitude of disorders, to spinal cord stimulation, peripheral nerve stimulation, cortical stimulation and cranial nerve stimulation, as well as non-invasive therapies and other implanted types of devices that interface with the nervous system. Allowing readers to better learn via case-based examples, this practical volume depicts real examples of decisions neuroscientists and neurosurgeons need to make every day from leaders in the field.

This book serves as a companion text to the editor's previous titles Essential Neuromodulation and Innovative Neuromodulation for neuroscience, neural engineering and biomedical engineering courses.

• Covers typical decision-making in the most frequent neuromodulation experiments and procedures across the widest array of scientists and practitioners
• Includes case-based chapters in an innovative, stepwise variant pathway format rather than being didactic in structure
• Provides for clinical, practical learning rather than serving as a reference on a particular topic

sectio I

Spinal cord stimulation

Outline

Chapter 1. Percutaneous trial lead placement for failed back surgery syndrome

Chapter 2. Percutaneous trial case for complex regional pain syndrome

Chapter 3. Percutaneous spinal cord stimulation trial for cervical lead placement

Chapter 4. Percutaneous permanent procedures

Chapter 5. Paddle placement for failed back surgery syndrome

Chapter 6. Paddle lead placement in the cervical spine region

Chapter 7. Paddle lead trial in the case of a prior fusion

Chapter 8. Complications involving spinal cord stimulation and implantable pulse generators

Chapter 9. Dorsal root ganglion stimulation

Chapter 10. Programming concerns with spinal cord stimulation

Chapter 1

Percutaneous trial lead placement for failed back surgery syndrome

Laura Lombardi-Karl, and Musa Moris Aner Anesthesiology, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA, United States

Abstract

A 57-year-old female with a history of L4-L5 and L5-S1 laminectomy and fusion presents with persistent axial back and left leg pain. She has been diagnosed with failed back surgery syndrome (FBSS). She has trialed several medial branch blocks and lumbar epidural steroid injections with minimal relief. She is currently taking gabapentin 300 mg three times daily and has participated in several courses of physical therapy with minimal benefit. She is anxious that no solutions will be found for her chronic pain and seems willing to try alternative therapies. Discussion takes place to consider spinal cord stimulation and the possibility of performing a trial of the stimulation to see if it can help her. She expresses interest in proceeding and is given some literature to review on the therapy.

Keywords

Failed back surgery syndrome; Percutaneous trial; Spinal cord stimulation (SCS)

Scenario

A 57-year-old female with a history of L4-L5 and L5-S1 laminectomy and fusion presents with persistent axial back and left leg pain. She has been diagnosed with failed back surgery syndrome (FBSS). She has trialed several medial branch blocks and lumbar epidural steroid injections with minimal relief. She is currently taking gabapentin 300 mg three times daily and has participated in several courses of physical therapy with minimal benefit. She is anxious that no solutions will be found for her chronic pain and seems willing to try alternative therapies. Discussion takes place to consider spinal cord stimulation and the possibility of performing a trial of the stimulation to see if it can help her. She expresses interest in proceeding and is given some literature to review on the therapy.

• Variation: Conservative multimodal management has not been trialed -- Spinal cord stimulation is generally considered after patients have failed more conservative management with medication, physical therapy, or other less invasive interventional techniques, although this is not necessarily required. Placement of SCS should not be viewed as a replacement or contraindication to multimodal analgesia, especially considering that patients often have multiple pain generators and pain is often multifactorial. In many cases, patients will continue taking adjuvant medications and pursuing physical therapy. However, there should be an effort to reduce opioid consumption, and a plan for opioid reduction should be discussed with the patient as part of preoperative planning.
• Variation: The patient has had multiple surgeries at different levels -- It is important to confirm the level of a patient's prior surgeries as this may interfere with safe placement of percutaneous leads. Laminectomies will result in a disrupted ligamentum flavum, while fusion hardware may interfere with imaging. Prior surgery can result in epidural scarring that extends beyond the level of surgery. This can interfere with the loss of resistance technique and pose difficulty threading leads. Severe central canal stenosis may be a contraindication for an SCS as placement of a space-occupying lead may cause myelopathy. Although this is of greater concern in cervical SCS placement, it should be considered at all levels. Before SCS implant, patients with FBSS should be reevaluated by their surgeon to ensure there are no structural issues that would require further surgery. It is also valuable to obtain updated imaging with contrast to assess for new or worsening pathology. Thoracic spine magnetic resonance imaging (MRI) can also be included as part of preoperative planning for thoracic SCS placement.
• Variation: The patient is elderly and has mild cognitive impairment but good family support -- Although family members help the patient to remember and effectively communicate at visits, using the device and communicating eventual needs for reprogramming and functional improvements may be hampered. At times, the patient's underlying pain state or comorbidities may influence the surgeon's choice of SCS manufacturer. Device selection is a complex process taking into account the characteristics of the patient's pain, surgeon's preference, and patient's ability to communicate. Patients with anxiety disorders or difficulty describing their pain may benefit from placement of a device that does not require extensive intraoperative mapping and patient cooperation, such as high-frequency 10 kHz. All elderly patients should go through psychiatric evaluation as standard of care, not necessarily to rule out placement but to find ways to optimize the patient for a better outcome.
• Variation: The patient has a history of breast cancer that has been in remission for 2 years -- Patients with medical conditions requiring frequent MRI imaging, such as cancer, may influence the choice of SCS device. Some SCS devices are fully MRI compatible, some are conditionally compatible, while some are not compatible at all. A full discussion with the patient's oncologist or other relevant providers regarding the likely need for future MRI imaging should occur before SCS placement. Similarly, there may be less utility in selecting an MRI-compatible device for patients who already have a contraindication to MRI, such as those with non–MRI-compatible pacemakers or deep-brain stimulators. Other patients who may have an increased need for MRI imaging include those with a concern for intracranial pathology, such as patients with a history of seizures or headache, as well as patients with multiple joint complaints or surgeries.

Scenario (continued)

A full physical examination is completed, and no new neurological deficits are noted. The patient's MRIs and relevant laboratory test results are reviewed, and she has had an unremarkable preoperative psychological assessment. The patient expresses reasonable expectations and understands SCS trial restrictions. The decision is made to proceed with a percutaneous SCS trial.

• Variation: The patient reports that she expects her pain to resolve after SCS placement -- It is important to consider both disease- and patient-specific factors when considering SCS. FBSS is an indication with high probability of success with SCS. Newer technology has enabled pain states traditionally resistant to SCS, such as axial low back pain, to have better response. Proper patient education and expectation setting is key for success and reduction of placebo, as well as false positives. Before trial, the potential range of outcomes should be discussed with the patient. Patients with unrealistic expectations, such as anticipation of complete pain relief, those who seem hesitant to proceed, and any patient with uncontrolled anxiety, depression, addiction, or other psychiatric issue, should be viewed with caution. We recommend all patients meet with a psychiatric health-care provider before SCS trial for a thorough evaluation of potential psychiatric barriers. Patients with a history of noncompliance with other treatment, unstable social or health insurance situations, and those with limited cognitive ability require thoughtful evaluation before proceeding. In addition, clinicians and patients should discuss possible differences in relief provided by the trial versus permanent implant. Ideally, this conversation should have been had at multiple times by multiple providers, including the surgeon and pain psychologist.
• Variation: The patient is on anticoagulation for atrial fibrillation -- Anticoagulation continues to be a barrier in SCS placement. Multiple guidelines exist; American Society of Regional Anesthesia (ASRA) guidelines are the most frequently used ones. Following these guidelines assumes that placement of an epidural infusion catheter is similar to placement of an SCS lead. Risk of stopping anticoagulation for SCS placement requires risk stratification and a thorough discussion with the patient's neurologist, cardiologist, or hematologist. Although physicians in other specialties may be familiar with surgical techniques, they may not be aware of the anticoagulation holding requirements for an SCS trial. Not only does anticoagulation need to be held in advance of the trial, it needs to be held for the duration of the trial. One important consideration is that although SCS trial and permanent placement may require holding anticoagulation for a relatively longer duration, this is only for two discrete intervals. After SCS placement, patients should then require fewer or no other injections, reducing the overall number of times anticoagulation will need to be held. The appropriate time to restart anticoagulation should also be discussed with the patient's multidisciplinary team. There is no consensus regarding the use of paddle versus percutaneous leads for permanent placement. All patients should be instructed to hold nonsteroidal anti-inflammatory drugs for 7 days, and then it is held for the duration of the trial. Exceptions to this include the selective Cox2 inhibitors.
• Variation: The patient is on chronic antibiotics for urinary tract infection prophylaxis, with no active signs of infection -- Active infection is a contraindication to proceeding with trial or permanent lead placement. We recommend patients be off of all antibiotics for 10 days before the procedure. Patients chronically on antibiotics (i.e., UTI prophylaxis) may continue. Perioperative antibiotics (cefazolin or clindamycin in patients allergic to penicillin) are recommended. We do not recommend routine use of postoperative antibiotics. Intraoperatively, strict adherence to a sterile technique is paramount, and a proper surgical technique is the first-line defense against infection. Vancomycin powder applied intraoperatively or IPG antimicrobial pouches could be considered. We recommend all patients have preoperative Methicillin-resistant Staphylococcus aureus (MRSA) screening before permanent implant; however, we do not advocate regular MRSA screening before an SCS trial. Patients who test positive are treated with intranasal mupirocin for 5 days preoperatively.

Scenario (continued)

Several weeks later, the woman returns to the operating room for the scheduled procedure. All preoperative assessments have been completed, and the procedure begins with the patient receiving mild sedation and placed in the prone position with cushioning and pillows so that she feels comfortable. She is awake and alert enough to readily answer questions and confirm issues throughout the procedure, and this status is checked frequently. The region for percutaneous needle entry is assessed with fluoroscopic imaging and infiltrated with 0.5% bupivacaine for comfort. The needle is placed and slowly advanced with a loss of resistance technique. The lead is placed though the needle after removal of the needle stylet. In short order, the lead is advanced along the midline toward the T7-8 level with small deviations corrected along the way. Only a short interlude of backing the electrode down and readvancing is necessary.

Stimulation begins once the lead is in a reasonable position and she reports that she has paresthesia feelings in the low back region and the left leg more than the right but does feel some coverage in the right leg lower down and in the foot slightly. This seems reasonable to work with for trial information, and a decision is made to leave only this one lead in place. Impedances are within reasonable ranges. The lead is then brought out through the opening, and a strain-relief loop is secured on the skin with Tegaderm. The end of the lead is left free and accessible for the later attachment to the portable stimulation device provided by the company for programming and stimulation. She is allowed to recover from the sedatio...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Preface
• sectio I. Spinal cord stimulation
• sectio II. Deep brain stimulation
• sectio III. Peripheral nerve stimulation
• sectio IV. Vagus nerve stimulation and responsive neurostimulation
• Index