Evidence-based consensus guidelines on patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain.

Spinal cord stimulation (SCS) has demonstrated effectiveness for neuropathic pain. Unfortunately, some patients report inadequate long-term pain relief. Patient selection is emphasized for this therapy; however, the prognostic capabilities and deployment strategies of existing selection techniques, including an SCS trial, have been questioned. After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, a steering committee was formed to develop evidence-based guidelines for patient selection and the role of an SCS trial. Representatives of professional organizations with clinical expertize were invited to participate as committee members. A comprehensive literature review was carried out by the steering committee, and the results organized into narrative reports, which were circulated to all the committee members. Individual statements and recommendations within each of seven sections were formulated by the steering committee and circulated to members for voting. We used a modified Delphi method wherein drafts were circulated to each member in a blinded fashion for voting. Comments were incorporated in the subsequent revisions, which were recirculated for voting to achieve consensus. Seven sections with a total of 39 recommendations were approved with 100% consensus from all the members. Sections included definitions and terminology of SCS trial; benefits of SCS trial; screening for psychosocial characteristics; patient perceptions on SCS therapy and the use of trial; other patient predictors of SCS therapy; conduct of SCS trials; and evaluation of SCS trials including minimum criteria for success. Recommendations included that SCS trial should be performed before a definitive SCS implant except in anginal pain (grade B). All patients must be screened with an objective validated instrument for psychosocial factors, and this must include depression (grade B). Despite some limitations, a trial helps patient selection and provides patients with an opportunity to experience the therapy. These recommendations are expected to guide practicing physicians and other stakeholders and should not be mistaken as practice standards. Physicians should continue to make their best judgment based on individual patient considerations and preferences.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Neuroablative Procedures for Patients With Cancer Pain.

BACKGROUND: Managing cancer pain once it is refractory to conventional treatment continues to challenge caregivers committed to serving those who are suffering from a malignancy. Although neuromodulation has a role in the treatment of cancer pain for some patients, these therapies may not be suitable for all patients. Therefore, neuroablative procedures, which were once a mainstay in treating intractable cancer pain, are again on the rise. This guideline serves as a systematic review of the literature of the outcomes following neuroablative procedures. OBJECTIVE: To establish clinical practice guidelines for the use of neuroablative procedures to treat patients with cancer pain. METHODS: A systematic review of neuroablative procedures used to treat patients with cancer pain from 1980 to April 2019 was performed using the United States National Library of Medicine PubMed database, EMBASE, and Cochrane CENTRAL. After inclusion criteria were established, full text articles that met the inclusion criteria were reviewed by 2 members of the task force and the quality of the evidence was graded. RESULTS: In total, 14 646 relevant abstracts were identified by the literature search, from which 189 met initial screening criteria. After full text review, 58 of the 189 articles were included and subdivided into 4 different clinical scenarios. These include unilateral somatic nociceptive/neuropathic body cancer pain, craniofacial cancer pain, midline subdiaphragmatic visceral cancer pain, and disseminated cancer pain. Class II and III evidence was available for these 4 clinical scenarios. Level III recommendations were developed for the use of neuroablative procedures to treat patients with cancer pain. CONCLUSION: Neuroablative procedures may be an option for treating patients with refractory cancer pain. Serious adverse events were reported in some studies, but were relatively uncommon. Improved imaging, refinements in technique and the availability of new lesioning modalities may minimize the risks of neuroablation even further.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/guidelines-on-neuroablative-procedures-patients-wi.

Peripheral Nerve Stimulation for Facial Pain Using Conventional Devices: Indications and Results.

Trigeminal branch stimulation is a type of peripheral nerve stimulation (PNS) used to treat a variety of craniofacial pain disorders. Common indications include trigeminal neuralgia, trigeminal neuropathic pain, trigeminal deafferentation pain, trigeminal postherpetic neuralgia, supraorbital neuralgia, and migraine headaches. Supraorbital and infraorbital arrays are the most common electrode configurations, although preauricular, mandibular branch, and subcutaneous peripheral nerve field stimulation arrays have also been described. Trigeminal branch stimulation may be used as a stand-alone neuromodulation therapy or it may be combined with occipital nerve, sphenopalatine ganglion, or Gasserian ganglion stimulation to treat more complex pain patterns. Consistent with other forms of PNS, trigeminal branch stimulation is a minimally invasive, safe, and straightforward method of treating medically refractory neuropathic pain.

ACR Appropriateness Criteria® Plexopathy.

MRI without and with contrast is the most accurate imaging method to determine whether a process is intrinsic or extrinsic to a nerve of the brachial or lumbosacral plexus. However, there are no Current Procedural Terminology codes to correspond to imaging studies of the brachial or lumbar plexus discretely. This assessment uses "MRI of the brachial plexus" or "MRI of the lumbosacral plexus" as independent entities given that imaging acquisition for the respective plexus differs in sequences and planes compared with those of a routine neck, chest, spine, or pelvic MRI, yet acknowledges the potential variability of ordering practices across institutions. In patients unable to undergo MRI, CT offers the next highest level of anatomic evaluation. In oncologic patients, PET/CT imaging can identify the extent of tumor involvement and be beneficial to differentiate radiation plexitis from tumor recurrence but provides limited resolution of the plexus itself. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Diagnostic Biopsy of a Motor Branch of the Superficial Peroneal Nerve to the Peroneus Longus: A Convenient Alternative for Motor Nerve Biopsy.

BACKGROUND: Motor nerve biopsy is performed to supplement clinical, serologic, and imaging data in the workup of neuropathies of unknown origin, especially when motor neuron disease is suspected. METHODS: We describe a surgical technique for biopsy of a motor branch of the superficial peroneal nerve innervating the peroneus longus muscle. RESULTS: Three patients presented with weakness concerning for motor neuropathy and underwent biopsy of a motor branch of the superficial peroneal nerve innervating the peroneus longus muscle. The surgical technique is described in detail. Biopsied tissue was sufficient for pathologic diagnosis. No patient suffered postsurgical sensory or motor deficits related to the procedure. No patient suffered postsurgical complications. CONCLUSIONS: Biopsy of the motor branch of the superficial peroneal nerve to the peroneus longus is a safe and effective alternative for motor nerve biopsy and can be easily combined with peroneus longus muscle biopsy.

Schwannomas of the foot and ankle: a technical report.

The present technical report provides a detailed description of open surgical resection of peripheral nerve sheath tumors in the foot and ankle. We present 3 cases to illustrate important differences in the technique based on the presentation, anatomic location, and intraoperative neurophysiologic monitoring findings. It is important for surgeons to understand that surgical excision of many peripheral nerve sheath tumors can be undertaken without en bloc resection of the entire nerve trunk.

Muscle and nerve biopsies: techniques for the neurologist and neurosurgeon.

OBJECTIVE: Muscle and nerve biopsies are commonly performed procedures for the diagnosis of neuromuscular disorders. Neurologists and neurosurgeons are often consulted to perform these procedures in clinical practice. We provide guidelines in the performance of muscle and nerve biopsies. METHODS: We describe the technique for performance of muscle and nerve biopsy, and review the relevant literature. RESULTS: The quadriceps muscle is the most typical biopsy site for most myopathies, whereas the sural nerve is the most common nerve biopsy site for most peripheral neuropathies. Other sites may be utilized depending upon the pattern of symptoms or the differential diagnosis. Motor nerves may be sampled in the setting of motor neuron disease, for example. We advocate the use of conduit repair to allow for sensory or motor recovery to occur following nerve biopsy. CONCLUSION: The muscle biopsy and nerve biopsy may be performed with high yield, low morbidity, and rare complications.

Spinal cord bypass surgery with intercostal and spinal accessory nerves: an anatomical feasibility study in human cadavers.

OBJECT: Despite extensive study, no meaningful progress has been made in encouraging healing and recovery across the site of spinal cord injury (SCI) in humans. Spinal cord bypass surgery is an unconventional strategy in which intact peripheral nerves rostral to the level of injury are transferred into the spinal cord below the injury. This report details the feasibility of using spinal accessory nerves to bypass cervical SCI and intercostal nerves to bypass thoracolumbar SCI in human cadavers. METHODS: Twenty-three human cadavers underwent cervical and/or lumbar laminectomy and dural opening to expose the cervical cord and/or conus medullaris. Spinal accessory nerves were harvested from the Erb point to the origin of the nerve's first major branch into the trapezius. Intercostal nerves from the T6-12 levels were dissected from the lateral border of paraspinal muscles to the posterior axillary line. The distal ends of dissected nerves were then transferred medially and sequentially inserted 4 mm deep into the ipsilateral cervical cord (spinal accessory nerve) or conus medullaris (intercostals). The length of each transferred nerve was measured, and representative distal and proximal cross-sections were preserved for axonal counting. RESULTS: Spinal accessory nerves were consistently of sufficient length to be transferred to caudal cervical spinal cord levels (C4-8). Similarly, intercostal nerves (from T-7 to T-12) were of sufficient length to be transferred in a tension-free manner to the conus medullaris. Spinal accessory data revealed an average harvested nerve length of 15.85 cm with the average length needed to reach C4-8 of 4.7, 5.9, 6.5, 7.1, and 7.8 cm. The average length of available intercostal nerve from each thoracic level compared with the average length required to reach the conus medullaris in a tension-free manner was determined to be as follows (available, required in cm): T-7 (18.0, 14.5), T-8 (18.7, 11.7), T-9 (18.8, 9.0), T-10 (19.6, 7.0), T-11 (18.8, 4.6), and T-12 (15.8, 1.5). The number of myelinated axons present on cross-sectional analysis predictably decreased along both spinal accessory and intercostal nerves as they coursed distally. CONCLUSIONS: Both spinal accessory and intercostal nerves, accessible from a posterior approach in the prone position, can be successfully harvested and transferred to their respective targets in the cervical spinal cord and conus medullaris. As expected, the number of axons available to grow into the spinal cord diminishes distally along each nerve. To maximize axon "bandwidth" in nerve bypass procedures, the most proximal section of the nerve that can be transferred in a tension-free manner to a spinal level caudal to the level of injury should be implanted. This study supports the feasibility of SAN and intercostal nerve transfer as a means of treating SCI and may assist in the preoperative selection of candidates for future human clinical trials of cervical and thoracolumbar SCI bypass surgery.

Spinal nerve root stimulation.

Spinal nerve root stimulation (SNRS) is a neuromodulation technique that is used to treat chronic pain. This modality places stimulator electrode array(s) along the spinal nerve roots, creating stimulation paresthesias within the distribution of the target nerve root(s), thereby treating pain in that same distribution. There are several different forms of spinal nerve root stimulation, depending upon the exact electrode positioning along the nerve roots. SNRS combines the minimally invasive nature, central location, and ease of placement of spinal cord stimulation with the focal targeting of stimulation paresthesias of peripheral nerve stimulation. This hybrid technique may be an effective alternative for patients in whom other forms of neurostimulation are either ineffective or inappropriate.

Spinal cord bypass surgery using peripheral nerve transfers: review of translational studies and a case report on its use following complete spinal cord injury in a human. Experimental article.

Spinal cord injury has been studied in a variety of in vitro and in vivo animal models. One promising therapeutic approach involves the transfer of peripheral nerves originating above the level of injury into the spinal cord below the level of injury. A model of spinal cord injury in rodents has shown the growth of peripheral nerve fibers into the spinal cord, with the subsequent development of functional synaptic connections and limb movement. The authors of this paper are currently developing a similar model in felines to assess the cortical control of these novel repair pathways. In an effort to determine whether these neurotization techniques could translate to spinal cord injury in humans, the authors treated a patient by using intercostal nerve transfer following complete acute spinal cord injury. The case presented details a patient with paraplegia who regained partial motor and sensory activity following the transfer of intercostal nerves, originating above the level of the spinal cord injury, into the spinal canal below the level of injury. The patient recovered some of his motor and sensory function. Notably, his recovered hip flexion showed respiratory variation. This finding raises the possibility that intercostal nerve transfers may augment neurological recovery after complete spinal cord injury.

Intra-abdominal vascular injury during trocar-assisted ventriculoperitoneal shunting: case report.

OBJECTIVE: Laparoscopic trocar injury is a relatively well-described complication of cholecystectomies and gynecological procedures. However, this type of injury has not been reported in association with adult neurological surgery. To increase awareness of this very serious risk, we report a case of intra-abdominal vascular injury during a shunt procedure involved with a common neurosurgical procedure. CLINICAL PRESENTATION: A 76-year-old man with no previous abdominal surgical history presented with probable normal pressure hydrocephalus. INTERVENTION: After an appropriate preoperative workup confirming probable normal pressure hydrocephalus, the patient consented to placement of a ventriculoperitoneal shunt with a programmable valve. During placement of the distal catheter using an abdominal trocar, the aorta was punctured inadvertently, necessitating emergency laparotomy for vascular repair. CONCLUSION: An abdominal trocar should be used with caution in ventriculoperitoneal shunt surgery. Even with meticulous technique, vascular injury can occur with any trocar-based abdominal procedure. The neurosurgeon who uses this technique must be prepared to initiate emergent vascular access and repair, with a vascular surgery team available should such an injury occur. Alternatively, open placement of peritoneal catheters avoids blind peritoneal instrumentation and is an effective method for minimizing potentially catastrophic vascular injuries.

An extramedullary foramen magnum cavernous malformation presenting with acute subarachnoid hemorrhage: case report and literature review.

OBJECTIVE AND IMPORTANCE: This case summarizes our experience with the first described intradural extramedullary cavernous malformation at the foramen magnum and reminds the neurosurgical community to consider cavernous malformations in the differential diagnosis for subarachnoid hemorrhage. CLINICAL PRESENTATION: A 21-year-old man presented with an occipital headache, photophobia, nausea, neck stiffness, and fever of 10 days' duration. A lumbar puncture yielded a clear pink fluid with 300 leukocytes/mm3 (30% neutrophils and 65% lymphocytes) and 42,200 erythrocytes/mm3, a protein count of 243 mg/dl, and a glucose count of 56 mg/dl. Computed tomography revealed a 1.5-cm right-sided dural-based mass of high attenuation that spanned the foramen magnum and a segment of the upper spinal canal. Magnetic resonance imaging showed a loculated, heterogeneously enhancing mass with a cystic component that slightly displaced the medulla to the left. An angiogram was negative for aneurysms and vascular malformations but did show an area of early filling and slow washout of the epidural venous plexus at the posterior canal margin of C1 and C2. INTERVENTION: A suboccipital craniectomy and C1 laminectomy were performed. Upon opening of the dura, an encapsulated mass was visualized. The lesion was located on the right lateral surface of the cervicomedullary junction and was entirely extraparenchymal. The mass was microsurgically dissected, and its associated venous malformation was left intact. The patient's postoperative course was uneventful, with a return to baseline function. Pathological examination confirmed the diagnosis of cavernous malformation. CONCLUSION: Our report not only presents a unique combination of pathological lesion, location, and presentation but also demonstrates that such lesions may be treated surgically with excellent results.

Intraoperative positioning nerve injuries.

Intraoperative positioning nerve injuries are regrettable complications of surgery thought to arise from stretch and/or compression of vulnerable peripheral nerves. Generally thought to be preventable, these injuries still occur in patients despite rigorous preventative measures. Sometimes injuries, initially thought to be due to malpositioning, are caused by other factors, such as retraction injury or brachial plexitis. Because of the diversity of nerves susceptible to positioning injury, the clinician must be aware of a variety of presentations and must be able to distinguish them from other postoperative complaints. Prevention remains the mainstay of the management of positioning injuries. Diagnosed and managed appropriately, these lesions typically improve completely over time.

Solitary cerebellar metastasis of malignant pleural mesothelioma: case report.

BACKGROUND: Malignant pleural mesothelioma is an uncommon malignancy that rarely metastasizes to the central nervous system and even less frequently occurs as a solitary lesion. CASE DESCRIPTION: We present a 71-year-old white female, nonsmoker, with no occupational exposure to asbestos. She presented with a 15-lb. weight loss over several months and persistent right subscapular pain radiating to her anterior chest. Imaging studies revealed a pleural mass, and biopsy confirmed fibrous type malignant pleural mesothelioma. During a metastatic workup, computed tomography (CT) and magnetic resonance imaging (MRI) of the head demonstrated a 1 cm subcortical, contrast-enhancing lesion without surrounding edema in the right posterior cerebellum. Surgical resection of the solitary cerebellar mass revealed fibrous-type metastatic malignant mesothelioma. Postoperatively, the patient received a combined chemotherapy regimen of Adriamycin and Cisplatin and underwent whole brain radiation therapy. CONCLUSIONS: We report the first resection of a solitary cerebellar metastasis of malignant pleural mesothelioma. We also review past cases of intracranial metastasis of this malignancy, its histologic subtypes, outcome, and recent treatment modalities.

Failure of intraoperative jugular bulb S-100B and neuron-specific enolase sampling to predict cognitive injury after carotid endarterectomy.

OBJECTIVE: Cognitive decline occurs in 25% of patients after carotid endarterectomy (CEA). Elevated serum concentrations of S-100B and neuron-specific enolase (NSE) occur after stroke, and serum S-100B levels at 24 hours are associated with clinical outcome after both stroke and CEA. We hypothesized that we could detect acute elevations in serum levels of these markers obtained intraoperatively from the jugular bulb (JB) and that these elevations would predict cognitive dysfunction postoperatively as measured by neuropsychometric test performance. METHODS: Forty-three patients scheduled for elective CEA were assessed with a battery of neuropsychometric tests before and 1 day after surgery. Before the carotid artery was clamped, a 6-French Fogarty catheter was inserted into the facial vein and threaded 6 cm rostrally into the JB. Serum samples were withdrawn from this catheter and simultaneously from a radial arterial catheter (A-line) at three time points: before clamping, 15 minutes into clamping, and after unclamping the carotid artery. Concentrations between groups were compared by analysis of variance and paired t tests. RESULTS: Total deficit scores were significantly worse in 13 (30%) of the 43 patients 1 day after surgery. There was a trend toward elevations in JB concentrations of S-100B relative to A-line levels 15 minutes after cross-clamping (11% elevation, P = 0.079, paired t test). In addition, 15 minutes after clamping of the carotid artery, levels of S-100B from the JB were significantly elevated compared with levels at baseline (P = 0.040, one-way analysis of variance). No significant changes were found between any time point in levels of S-100B from the A-line blood or of NSE from either the JB or the A-line. Subtle cognitive decline after CEA was not correlated with intraoperative levels of S-100B or NSE, but there was a weak, statistically nonsignificant, association between a rise in 15-minute S-100B levels and cognitive injury that was not seen with JB samples. CONCLUSION: Although intraoperative levels of S-100B and NSE from the JB failed to predict cognitive injury, carotid cross-clamping, independent of injury, seems to be associated with early elevations in S-100B.

A controlled prospective study of neuropsychological dysfunction following carotid endarterectomy.

BACKGROUND: Although subtle cognitive injury as revealed by neuropsychological testing occurs in a substantial number of patients following carotid endarterectomy (CEA), there is controversy about whether this finding is a result of the surgery or the anesthesia. OBJECTIVES: To examine the changes in neuropsychological test performance in patients following CEA vs a control group of patients older than 60 years following spine surgery, so as to determine whether neuropsychological dysfunction after CEA is a result of surgery or anesthesia. METHODS: Patients undergoing CEA (n = 80) and lumbar spine surgery (n = 25) were assessed with a battery of neuropsychological tests preoperatively and on postoperative days 1 and 30. The neuropsychological performance of patients in the control group was used to normalize performance for patients in the CEA group, by calculating z scores using the mean and SD of the change scores in the control group. Significant cognitive dysfunction was defined as performance that exceeded 2 SDs above the mean performance of patients in the control group. RESULTS: Postoperative days 1 and 30 total deficit scores were significantly worse in the CEA group compared with the controls. When individual test results were examined, the CEA group performed significantly worse than the controls on the Rey Complex Figure test and Halstead-Reitan Trails B on day 1, and on the Rey Complex Figure on day 30. Overall, cognitive dysfunction was seen in 22 patients (28%) in the CEA group on day 1 and in 11 (23%) of 48 patients on day 30. CONCLUSIONS: Subtle cognitive decline following CEA occurs and persists for at least several weeks after surgery. This decline was absent in a control group.