Obstetric and nonobstetric anesthesia for patients with neurologic disorders

INTRODUCTION — Neurologic disorders add unique, and at times challenging, considerations for the anesthetic management for surgery, and for labor and delivery. This topic discusses a general approach to anesthetic management of patients with neurologic diseases and reviews important considerations for selected conditions.

Perioperative care of patients with neurologic disorders, the effects of pregnancy on neurologic disorders, and the effects of neurologic disorders on obstetric care are discussed separately. (See "Neurologic disorders complicating pregnancy" and "Perioperative care of the surgical patient with neurologic disease".)

Anesthesia concerns for specific neurosurgical procedures are also discussed separately. See individual topic reviews.

GENERAL CONSIDERATIONS FOR ALL PATIENTS — Surgical and obstetric patients may present with a wide range of neurologic diseases, some rare. Literature on anesthetic management often consists of case reports or retrospective reviews of small numbers of cases, which provide little guidance. Disease specific concerns are discussed below. Considerations that apply to all patients with neurologic diseases include the following:

Timing of preanesthesia evaluation — Whenever possible, patients with neurologic disorders should have preanesthesia consultation prior to surgery, and for obstetric patients, well in advance of delivery. Prior records should be reviewed, including imaging studies, and if necessary, a multidisciplinary management plan can be created. For obstetric patients, such a plan should consider the optimal mode of delivery and the anesthetic implications for labor analgesia, instrumented delivery, and scheduled or potential cesarean delivery. Preanesthesia consultation allows the patient time to consider risks and benefits of anesthetic options (table 1). (See "Anesthesia for cesarean delivery", section on 'Preoperative assessment'.)

Course and severity of neurologic disease — Preanesthesia evaluation should consider the following:

●Current treatment regimen, including medications that may affect anesthetic management

●Weakness, bulbar symptoms, cognitive dysfunction, or seizures

●Effects of neurologic disease on other organ systems (eg, cardiac, pulmonary)

Pregnancy may affect the course of some neurologic diseases. Both the existing severity of disease and the likely severity at the time of delivery should be assessed. (See "Neurologic disorders complicating pregnancy".)

Choice of analgesic or anesthetic technique — Neurologic disorders may have implications for the choice of anesthetic technique (ie, general anesthesia [GA], regional anesthesia, local anesthesia [LA] with or without sedation). For obstetric patients, neuraxial anesthesia techniques are preferred methods for both analgesia for labor and anesthesia for cesarean delivery. Each parturient should be viewed as a potential candidate for operative delivery during labor, possibly on an emergent basis. Risks of neuraxial anesthesia must always be balanced against the patient specific risks of alternative methods of labor analgesia (eg, systemic opioids) and the risks of GA if cesarean delivery is required. (See "Anesthesia for cesarean delivery", section on 'General versus neuraxial anesthesia' and "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Indications for neuraxial analgesia' and "Pharmacologic management of pain during labor and delivery", section on 'Pharmacologic options for labor analgesia'.)

For all patients who have neurologic or neuromuscular conditions, some general concerns include the following:

●Risk of brain herniation in patients with intracranial masses or increased intracranial pressure (ICP).

●Risk of hyperkalemia, rhabdomyolysis, or malignant hyperthermia after administration of succinylcholine and/or potent inhalational anesthetics for GA.

●Difficulty with airway management or neuraxial procedures because of distorted anatomy.

●Risks associated with alternatives to neuraxial techniques, including the patient-specific risks of GA, the adverse effects of systemic opioids, and less effective analgesia for labor or postsurgical pain.

BRAIN TUMORS — Patients with brain tumors may require anesthesia for procedures other than craniotomy for tumor removal. Anesthesia for such procedures is discussed here. Anesthesia for craniotomy and brain tumors during pregnancy are discussed separately. (See "Anesthesia for craniotomy in adults" and "Neurologic disorders complicating pregnancy", section on 'Brain tumors'.)

Neuraxial anesthesia for patients with brain tumors — The principle concerns regarding neuraxial anesthesia for patients with brain tumors are the following:

●The risk of herniation of brain tissue with the decrease in lumbar cerebrospinal fluid (CSF) pressure that occurs after dural puncture, either intentional dural puncture with a spinal needle, or unintentional dural puncture with an epidural needle.

●The risk of dangerous increase in intracranial pressure (ICP) following large volume or bolus epidural catheter dosing.

A space-occupying lesion does not always preclude neuraxial techniques. Uneventful epidural and spinal analgesia and anesthesia for delivery have been described in patients with intracranial tumors [1-3]. Neurologic or neurosurgical consultation should be obtained whenever possible prior to proceeding with neuraxial anesthesia for patients with brain tumors. The consultant should be asked specifically whether dural puncture would likely result in brain herniation; these determinations must be individualized. Neuroimaging should be reviewed for mass effect (eg, vasogenic edema, effaced cisterns, lateral shift of midline structures), hydrocephalus, and obstruction of CSF flow at or above the level of the foramen magnum. If there are clinical and radiologic signs of significant mass effect or obstruction of CSF flow, the patient is likely at high risk of brain herniation after dural puncture, and neuraxial anesthesia should generally not be performed. For patients who are felt to be at lower risk of brain herniation, the risks and benefits of neuraxial anesthesia should be discussed among the neurologist, obstetrician, anesthesiologist, and the patient [4].

Since epidural techniques can carry the risk of dural puncture even by experienced providers, an epidural technique would not be a safe alternative if a spinal anesthetic with a small gauge needle is deemed risky. Since epidural placement involves a much larger gauge needle (16 G or 17 G for epidural compared with 25 G or 27 G for spinal), when an unintentional dural puncture occurs during an epidural technique, the loss of CSF and pressure gradient between the intracranial and spinal CSF compartments may be much greater.

General anesthesia for patients with brain tumors — General anesthesia (GA) may be the only appropriate option for surgery, and may be required for emergency cesarean delivery, or for elective cesarean delivery if neuraxial anesthesia is contraindicated. GA for cesarean delivery is discussed separately. (See "Anesthesia for cesarean delivery".)

The basic principles for GA in patients with brain tumors are similar in pregnant and non-pregnant patients (eg, avoidance of further increase in ICP, maintenance of adequate cerebral perfusion), and are also discussed separately. (See "Anesthesia for craniotomy in adults", section on 'Induction of anesthesia' and "Anesthesia for craniotomy in adults", section on 'General concerns'.)

In patients with existing or potential for increased ICP during endotracheal intubation, opioids are commonly administered along with anesthesia induction agents. During induction of anesthesia for cesarean delivery, the benefits of opioids must be balanced against the risk of neonatal respiratory depression, as all opioids cross the placenta. Remifentanil is an attractive option, as its rapid onset and ultrashort duration of action facilitate rapid emergence and smooth extubation; however, remifentanil may cause brief neonatal respiratory depression, in some cases requiring naloxone or intubation [5-9].

Ventilation must be closely controlled for patients with increased ICP. We maintain PaCO₂ in the normal range (35 to 38 mmHg for nonpregnant patients, 28 to 32 mmHg for pregnant patients at term) during GA. Hypercarbia should always be avoided in patients with increased ICP, as elevations in PCO₂ result in increased cerebral blood flow and may further increase ICP. Hyperventilation and hypocarbia should also be avoided, except for an emergent need to reduce ICP. Severe hyperventilation can cause cerebral vasoconstriction and cerebral hypoperfusion, and in pregnant patients, uterine artery vasoconstriction and decreased blood flow to the fetus [10]. (See "Anesthesia for craniotomy in adults", section on 'Ventilation'.)

Arterial blood gases are used rather than end-tidal carbon dioxide (ETCO₂) to guide intraoperative ventilation in nonpregnant patients with increased ICP, since a number of factors (eg, age, lung disease, surgical positioning) can cause a discrepancy between ETCO₂ and PaCO₂. Compared with non-pregnant patients, the ETCO₂ more accurately reflects PaCO₂ in pregnant patients and can be used to guide ventilation in patients with increased ICP [11]. (See "Anesthesia for craniotomy in adults", section on 'Ventilation'.)

IDIOPATHIC INTRACRANIAL HYPERTENSION — Patients with idiopathic intracranial hypertension (IIH; also known as pseudotumor cerebri) have an elevated intracranial pressure (ICP) in the absence of a space-occupying lesion, ventriculomegaly, or abnormal cerebrospinal fluid (CSF) composition. IIH may worsen during pregnancy, though it is not clear whether this relates to weight gain or other aspects of pregnancy. The most serious consequence is risk of permanent visual loss. (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Clinical features and diagnosis".)

The physiology of intracranial contents, compliance, and pressures are discussed separately. (See "Evaluation and management of elevated intracranial pressure in adults", section on 'Physiology'.)

Neuraxial anesthesia for patients with IIH — Patients with idiopathic intracranial hypertension (IIH) are not generally at risk for brain herniation after dural puncture, and in fact CSF drainage (serial lumbar puncture or lumbar drain) may be used therapeutically in patients with IIH. (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Epidemiology and pathogenesis" and "Idiopathic intracranial hypertension (pseudotumor cerebri): Prognosis and treatment".)

Patients with IIH may experience transient increases in ICP and headache, nausea, or transient visual loss, as a result of labor pain, uterine contractions, valsalva, epidural bolus administration, or airway manipulation. Continuous spinal [12,13], epidural [14], and combined spinal-epidural analgesia [15,16] have been used in patients with IIH and may prevent pain-related increases in ICP, facilitate instrumented delivery, and avoid the need for general anesthesia (GA) and endotracheal intubation.

Concerns regarding neuraxial anesthesia (NA) in patients with IIH include the following:

●Epidural analgesia – Epidural boluses should be injected incrementally and slowly in patients with increased ICP. We suggest a slow bolus of approximately 5 mL every five to seven minutes, though this recommendation is not evidence-based. Injection of a solution into the epidural space displaces CSF upward and increases ICP; this effect is the suggested basis for initial relief of symptoms of post dural puncture headache (PDPH) after epidural blood patch. (See "Post dural puncture headache", section on 'Mechanism of action'.)

However, in patients with increased ICP, the further increase with epidural injection may be substantial. In case reports of two patients (nonpregnant) with ICP monitors after traumatic brain injury, injection of 10 mL of epidural solution increased ICP from an average of approximately 19 mmHg to 40 mmHg, which was maintained for an average of 4.5 minutes [17]. Injection of 5 mL increased ICP from approximately 17 to 22 mmHg, for an average of 3 minutes. Rarely, abrupt increase in ICP can cause retinal or vitreal hemorrhage and blindness [18].

●Continuous spinal analgesia – Continuous spinal analgesia is not routinely used for labor analgesia, but may be considered for laboring patients with IIH who are at high risk of cesarean delivery (see "Anesthesia for cesarean delivery", section on 'Drugs for continuous spinal anesthesia'). The ability to achieve rapid, titratable surgical anesthesia with a small volume of spinal anesthetic drug averts the need for a large, rapid epidural bolus in the event of an urgent operative delivery. Furthermore, an in situ spinal catheter can also be used to drain CSF for patients who become symptomatic with increased ICP during labor [12]. If a large volume of CSF is removed during the neuraxial procedure (eg, during spinal catheter placement), subsequent intrathecal local anesthetic (LA) administration should be carefully titrated, as a higher than expected spinal level has been reported [19].

While PDPH occurs at a high rate in parturients after continuous spinal analgesia, it is thought to be less common in patients with IIH, as low CSF pressure is extremely uncommon in patients with IIH, even after lumbar puncture [20]. The true incidence of PDPH in patients with IIH is unknown.

General anesthesia for patients with IIH — IIH is primarily a disease of patients with obesity, who may be at risk for difficulty with airway management during GA. (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Epidemiology and pathogenesis", section on 'Risk factors' and "Airway management for induction of general anesthesia", section on 'Prediction of the difficult airway'.)

Principles of GA for patients with IIH are similar to the principles that guide management for patient with brain tumors associated with increased ICP. (See 'General anesthesia for patients with brain tumors' above.)

CEREBROVASCULAR DISORDERS

Ischemic or hemorrhagic stroke — Anesthesia may be necessary for patients who require surgery or delivery after acute stroke. Surgery should be deferred when possible in the setting of acute stroke, as adverse outcomes are likely to be increased. Deferral of surgery after acute stroke in nonpregnant patients is discussed separately. (See "Perioperative stroke following noncardiac, noncarotid, and nonneurologic surgery", section on 'Timing of surgery after ischemic stroke'.)

Data to predict the risks for pregnant patients with recent stroke are lacking. Management depends on the patient's clinical condition and urgency of surgery or delivery. Basic principles of airway protection and hemodynamic control apply. Elevated intracranial pressure (ICP) may occur in patients with acute stroke and may affect anesthetic management. (See 'Brain tumors' above and "Initial assessment and management of acute stroke".)

Patients who have paralysis after stroke are at risk of potentially life-threatening hyperkalemia after administration of succinylcholine, which is usually administered as part of rapid sequence induction and intubation for general anesthesia. This issue is discussed separately. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Adverse effects of succinylcholine'.)

For labor and delivery, neuraxial anesthesia techniques optimize pain management and are the techniques of choice unless contraindicated due to anticoagulation or the impact of stroke on intracranial anatomy and physiology. Neuraxial anesthesia techniques may not be possible in patients who are unable to cooperate or with altered mental status [21].

For patients who require antithrombotic therapy for stroke prevention or anticoagulation for treatment, neuraxial anesthesia techniques must be coordinated with medication administration, and in some cases may be contraindicated due to the risk of spinal epidural hematoma. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Spinal epidural hematoma'.)

Stroke during pregnancy is discussed separately. (See "Cerebrovascular disorders complicating pregnancy".)

Intracranial aneurysm and arteriovenous malformation — Patients who have had complete surgical repair of intracranial aneurysm or arteriovenous malformation (AVM) do not require changes to usual anesthetic management.

For patients with residual or untreated lesions, a multidisciplinary plan should be created for surgical or obstetric and anesthetic management, with the goal of avoiding lesion rupture. In general, neurology consultation should be obtained whenever possible, to address the possible need for imaging (or re-imaging if surgical repair was remote in time) and other aspects of management. The primary concern for anesthetic management is avoidance of hypertension, which would increase the pressure gradient across the wall of the lesion and could cause rupture. Increase in the pressure gradient and rupture can also theoretically be caused by an abrupt decrease in CSF pressure, as may occur after dural puncture during NA. The true risk of aneurysm or AVM rupture after dural puncture cannot be determined. There are several case reports of aneurysmal rupture that may have been related to spinal anesthesia or diagnostic lumbar puncture [22-24]. However, given the relatively high incidence of unknown intracranial lesions and the frequency of spinal anesthesia, the risk of rupture with dural puncture is likely very low. (See "Unruptured intracranial aneurysms", section on 'Epidemiology'.)

The decision to perform neuraxial techniques for surgery, labor analgesia, or cesarean delivery must balance the risks and benefits of these techniques compared with the alternatives. For obstetric patients, we generally prefer neuraxial analgesia and anesthesia for patients with known intracranial aneurysms and AVMs. Considerations for anesthesia for these patients include the following:

●Neuraxial labor analgesia mitigates the increase in blood pressure that occurs during labor by providing more effective pain relief, compared with no analgesia or with alternative methods of labor analgesia. It facilitates instrumented vaginal delivery, and decreases the need for GA for cesarean delivery. The risk of significant intracranial hypotension after dural puncture may be reduced by the use of a small gauge, pencil point spinal needle. Epidural analgesia avoids dural puncture in most cases, but if an unintentional dural puncture occurs with the much larger epidural needle, CSF leak may be significantly greater than with a small gauge spinal needle.

●GA avoids dural puncture, but requires endotracheal intubation, which may be associated with hypertension during intubation and extubation, in addition to the risks of GA that apply to all obstetric patients. (See "Anesthesia for cesarean delivery", section on 'Choice of anesthetic technique'.)

The principles of management of GA for obstetric patients with intracranial vascular lesions are similar to non-obstetric patients, and are discussed separately. (See "Anesthesia for intracranial neurovascular procedures in adults".)

For patients with intracranial vascular lesions who develop a headache after a neuraxial anesthesia procedure, a high index of suspicion of intracranial hemorrhage should be maintained while evaluating the patient for possible post dural puncture headache (PDPH). For these patients, neurology consultation should be obtained before performing an epidural blood patch for presumed PDPH. (See "Post dural puncture headache", section on 'Differential diagnosis'.)

MULTIPLE SCLEROSIS — Multiple sclerosis (MS) is a relapsing and remitting disease that may include symptoms of optic neuritis, weakness, numbness, or ataxia.

Risk of relapse — The signs and symptoms of MS may worsen in the postoperative period, due to the stress of surgery, perioperative fever, or infection. MS activity tends to decrease during pregnancy and increase in the early postpartum period, with overall no net effect on the disease course. The risk of postpartum relapse is greater in patients with more severe MS prior to pregnancy. (See "Multiple sclerosis: Pregnancy planning", section on 'MS activity in pregnancy and postpartum'.)

Patients with MS should understand that MS may worsen after surgery or delivery, regardless of the type of anesthesia they receive.

Risks of neuraxial anesthesia in patients with MS — Neuraxial anesthesia techniques (spinal, epidural, or combined spinal-epidural) may be performed for patients with multiple sclerosis (MS) without increasing the risk of disease progression.

Historically, MS was considered a contraindication to neuraxial anesthesia. Since all local anesthetics (LAs) may be neurotoxic in vitro, the concern has been that LAs might affect demyelinated regions of the spinal cord, and cause acute MS attacks, exacerbation of underlying disease, or increase the risk of relapse. However, small retrospective studies [25] and two large prospective studies of patients with MS have reported no increase in the rate of relapse after delivery in patients who received epidural analgesia [26-28]. Findings from the two prospective studies are as follows:

●In the Pregnancy with Multiple Sclerosis (PRIMS) study conducted in 12 European countries, 254 women were followed during 269 pregnancies [26] and for 227 of those patients for two years postpartum [27]. Forty two patients received epidural labor analgesia. There was no significant difference in the rate of relapse, occurrence of at least one relapse in the first three postpartum months, or acceleration of the progression of disability in the postpartum period in patients who received epidural analgesia, compared with those who did not.

●A prospective study that followed 423 pregnancies in 415 women for at least one postpartum year reported no difference in the relapse rate or degree of MS-related disability in 65 patients who had epidural analgesia for labor or epidural anesthesia for cesarean delivery, compared with those who did not [28].

Limitations of these two studies include the small number of women who received epidural analgesia or anesthesia, and the fact that the studies were not randomized and may have been subject to selection bias. Women who chose epidural analgesia may have had milder MS which would reduce the odds of a postpartum relapse and affect the study results.

Neuraxial anesthesia techniques in patients with MS — Epidural and single-shot spinal techniques can be utilized in patients with MS. We choose neuraxial analgesia and anesthesia techniques for patients with MS as we would for patients without the disease. Epidural administration of LA for cesarean delivery has historically been thought to be less risky for patients with MS than a spinal technique because the initial CSF concentration of LA is higher following a subarachnoid block [29]. However, the limited available evidence does not support this theory. There have been a number of case reports of an association between spinal anesthesia and subsequent exacerbation of MS [30-32]. In contrast, a single center retrospective review of 35 neuraxial anesthetics in patients with MS reported no cases of exacerbation of MS in patients who had either spinal (17 patients) or epidural (18 patients) anesthesia [33].

During labor analgesia, epidural medications infused over time or in high concentrations may accumulate in CSF. The concentrations and duration of epidural infusion that might increase risk in patients with MS are unknown. In addition, the relative risks of the subarachnoid doses of LA used for labor analgesia, compared with the low dose labor epidural solutions that are standard practice, are unknown.

GUILLAIN-BARRÉ SYNDROME — Guillain-Barré syndrome (GBS) is an acute immune-mediated monophasic illness causing a rapidly progressive polyneuropathy with weakness or paralysis. Patients with GBS may require surgery for acute illnesses, for tracheostomy, or for feeding tube insertion. GBS does not appear to occur with increased frequency during pregnancy but may occur at increased frequency in the postpartum period. (See "Neurologic disorders complicating pregnancy", section on 'Guillain-Barré syndrome'.)

Risks of neuraxial anesthesia in GBS — No causative link has been established between neuraxial analgesia or anesthesia and recurrence or worsening of Guillain-Barré syndrome (GBS). The relevant literature consists of very few case reports. A series of four cases of GBS that occurred one to two weeks after epidural anesthesia included one that occurred after a cesarean delivery [34]. A subsequent review of the literature identified reports of 30 cases of GBS during pregnancy between 1986 and 2002, in patients who were in various stages of recovery at the time of delivery [35]. Neuraxial techniques were used in five cases, including four epidurals and one combined spinal-epidural, without relapse or worsened symptoms.

Other anesthetic concerns for patients with GBS

Neuromuscular blocking agents — Succinylcholine is contraindicated in patients with neurologic deficits related to GBS, and for an unknown period of time after recovery, because of the potential for life-threatening hyperkalemia. Hyperkalemic cardiac arrest has been reported in a parturient who received succinylcholine three weeks after apparent full recovery from GBS [36]. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Adverse effects of succinylcholine'.)

Patients with acute GBS are extremely sensitive to nondepolarizing neuromuscular blocking agents (eg, rocuronium, vecuronium, cisatracurium); doses should be reduced and titrated to effect, with dosing and reversal guided by quantitative neuromuscular monitoring whenever possible. If high dose rocuronium is administered as part of rapid sequence induction and intubation for patients with GBS, recovery from neuromuscular blockade may be prolonged. In this scenario, sugammadex may be considered to hasten recovery from neuromuscular blockade [37]. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Reversal of neuromuscular block' and "Monitoring neuromuscular blockade", section on 'When and how to monitor neuromuscular blockade'.)

Autonomic dysfunction — Autonomic dysfunction occurs in 70 percent of patients with acute GBS and manifests as tachycardia, hypertension alternating with hypotension, orthostatic hypotension, bradycardia, and other arrhythmias. (See "Guillain-Barré syndrome in adults: Treatment and prognosis", section on 'Cardiovascular and autonomic status'.)

During neuraxial anesthesia or general anesthesia (GA), patients with acute GBS may exhibit exaggerated hypotension after blood loss, changes in posture, or the sympathectomy associated with neuraxial block. Similarly, noxious stimuli (pain, airway manipulation) can cause either vagal or enhanced sympathetic responses. For patients with autonomic dysfunction, we maintain left uterine displacement whenever the patient is supine to maximize venous return. For operative delivery, we prefer a titrated technique (epidural anesthesia or low dose/sequential combined-spinal epidural [CSE]) to minimize hypotension whenever possible. In our experience, both of these techniques require time (30 to 45 minutes) to achieve the desired block height. (See "Epidural and combined spinal-epidural anesthesia: Techniques", section on 'Dose of spinal drugs'.)

Patients with hemodynamic instability may require continuous invasive arterial blood pressure monitoring. Indirect sympathomimetic agents (ie, ephedrine) for blood pressure support may be unpredictable [38]. Therefore, direct-acting sympathomimetic agents (ie, phenylephrine) are preferred.

Need for anticoagulation — Patients with acute GBS are at increased risk of deep vein thrombosis and often receive pharmacologic thromboprophylaxis. Timing of neuraxial techniques must be coordinated with medication administration and in some cases may be contraindicated, because of the risk of spinal epidural hematoma [39,40]. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication".)

SPINE AND SPINAL CORD ABNORMALITIES

Chiari malformation — Chiari malformations are congenital conditions defined by anomalies of the craniocervical junction with downward displacement of the cerebellar structures and potential for partial or intermittent obstruction of cerebrospinal fluid (CSF). There are three main types of Chiari malformations (CM-I, II, and III). Most patients who become pregnant have Chiari type 1, in which there is downward displacement of abnormally shaped cerebellar tonsils below the level of the foramen magnum. (See "Chiari malformations".)

Literature on the anesthetic management of patients with Chiari malformations consists of case reports and case series [41-45], and a multicenter retrospective database review [46]. Neuraxial anesthesia techniques have been used in obstetric patients with uncorrected and surgically-corrected CM-I, and in patients without new or worsening symptoms related to Chiari malformations during pregnancy [45]. In most cases, there have been no exacerbations of symptoms or anesthesia related complications of Chiari malformations.

Important concerns for anesthesia include:

●The degree of obstruction or potential obstruction of CSF flow between the intracranial and spinal compartments, and the associated risk of brain herniation after dural puncture. (See 'Neuraxial anesthesia for patients with brain tumors' above.)

●Associated manifestations that vary widely, and may affect anesthetic management, including syringomyelia, scoliosis, tethered spinal cord, seizures, sleep-related breathing disorders, cranial nerve abnormalities, neurofibromatosis, and Noonan syndrome. (See "Chiari malformations", section on 'Associated conditions' and "Chiari malformations", section on 'Clinical manifestations' and "Noonan syndrome", section on 'Surgical and anesthetic considerations'.)

Disorders of the vertebral column and spinal cord — There is a wide range of abnormality and severity of spine and spinal cord disorders that can result in an equally wide range of symptoms and neurologic compromise. In many cases, patients with these disorders should have radiologic imaging to define the relevant anatomy if neuraxial anesthesia is planned. Examples of anesthetic implications of these disorders include the following:

●Succinylcholine is contraindicated for patients with motor deficits as a result of spinal cord abnormalities, because of the risk of life-threatening hyperkalemia. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Adverse effects of succinylcholine'.)

●Patients with cervical spinal cord disorders may be at increased risk of difficulty with airway management for general anesthesia (GA) due to progressive kyphosis or restricted motion after corrective spine surgery.

●Patients with spine and spinal cord abnormalities may be at increased risk for difficult neuraxial procedures, unintentional dural puncture during epidural anesthesia, and/or unpredictable or patchy block due to distorted anatomy or postsurgical changes. In patients with asymptomatic isolated vertebral arch defects (sometimes called spina bifida occulta), which are the most common form of closed spinal dysraphism, it may also be difficult to use surface landmarks to guide NA, and preprocedure ultrasound may be helpful. (See "Closed spinal dysraphism: Pathogenesis and types", section on 'Isolated vertebral defects'.)

●Patients with a tethered cord have a low-lying conus medullaris and a thickened filum terminale. With or without corrective surgery, the conus medullaris may remain in an abnormally low position [47], and the spinal cord may be more posteriorly situated than a normal spinal cord [48]. Patients with a tethered cord are at increased risk of spinal cord trauma during spinal anesthesia, and may have unpredictable spread of local anesthetic (LA) during epidural anesthesia. (See "Closed spinal dysraphism: Clinical manifestations, diagnosis, and management", section on 'Tethered cord syndrome'.)

•For patients with uncorrected tethered spinal cords, we avoid neuraxial techniques due to increased risk for direct needle trauma to the spinal cord and nerve roots.

•For patients with tethered cord following corrective surgery, we consider neuraxial anesthesia only after a neurosurgical consultation and review of a lumbar spine magnetic resonance imaging (MRI) that shows the precise location of the conus medullaris, and the optimal space for neuraxial anesthesia. In patients with corrected tethered spinal cord, we use preprocedure ultrasound of the lumbar spine before neuraxial procedures to accurately identify the target intravertebral level, guided by the MRI. (See "Spinal anesthesia: Technique", section on 'Preprocedure ultrasonography'.)

●Patients with syringomyelia are theoretically at risk for extension of the syrinx with rapid epidural bolus injection, or as a result of increase in intracranial pressure (ICP) during intubation. In a limited number of case reports, epidural and spinal anesthesia have been used without complications in select patients for spontaneous and assisted vaginal delivery and for cesarean delivery [49,50]. We avoid NA techniques in patients with progression of syrinx-related symptoms during pregnancy, and administer epidural boluses very slowly if an epidural technique is used.

Disc disease, spinal stenosis, and radiculopathy — Disc disease and spinal stenosis are common structural causes of back pain and nerve injuries. One or more nerve roots may be affected. (See "Polyradiculopathy: Spinal stenosis, infectious, carcinomatous, and inflammatory nerve root syndromes" and "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis", section on 'Disc herniation'.)

We provide neuraxial anesthesia only after a careful documentation of the baseline neurologic deficits, symptomatology with positioning, and discussion of the risks and benefits of neuraxial techniques with the patient. (See "Patient positioning for surgery and anesthesia in adults", section on 'Trial positioning'.)

Back pain and radiculopathy may be worse after surgery or labor and delivery, whether GA or neuraxial anesthesia is used. Symptoms related to positioning or other factors (eg, nerve compression during labor or delivery) are masked during anesthesia, and may only be apparent after anesthesia resolves. When this occurs after neuraxial anesthesia, the injury may be attributed to the neuraxial procedure.

Literature on the effects of neuraxial anesthesia on symptoms related to spinal stenosis or lumbar disc disease is inconclusive, and there are insufficient data to offer definitive guidance [51]. Retrospective reviews and case reports suggest that patients with spinal stenosis or compressive lumbar disc disease may be at increased risk of neurologic complications after neuraxial anesthesia [29,52,53]. Proposed mechanisms for injury include mechanical trauma [53], LA neurotoxicity [54,55], and/or neural ischemia related to compressive effects of injected or infused drug solutions [56]. However, surgical factors, patient positioning, or a combination of factors may also be involved. Examples of studies of neurologic complications in patients with spinal stenosis or disc disease include the following:

●A retrospective study of 937 patients with preexisting spinal canal pathology (including 20 percent with spinal stenosis and 61 percent with lumbar radiculopathy) who received neuraxial anesthesia found the incidence of new neurologic deficits or worsening of preexisting symptoms was 1.1 percent (95% CI 0.5-2 percent) [52]. There was no control group with similar pathology who underwent GA, so the effect of neuraxial anesthesia could not be determined. The overall block success was 97.2 percent.

●In a large retrospective database review of approximately 1,700,000 neuraxial anesthetics over 10 years, spinal stenosis was identified as a risk factor for postoperative neurologic complications [54]. Among 85 patients with permanent neurologic injury (ie, cauda equina syndrome or paraparesis), 14 had spinal stenosis.

●In a retrospective survey of spinal complications after neuraxial anesthesia over the course of one year in France, 5 of the 12 patients with neurologic damage lasting greater than three months had spinal stenosis [57].

●One small study reported a higher incidence of paresthesias during neuraxial anesthesia in patients with spinal pathology, without evidence of long-term neurologic injury [53].

Spinal cord injury — Anesthesia for patients with acute and chronic spinal cord injury, including patients at risk for autonomic dysreflexia, is discussed separately. (See "Anesthesia for adults with acute spinal cord injury" and "Anesthesia for adults with chronic spinal cord injury".)

CEREBROSPINAL FLUID SHUNTS — Either general anesthesia (GA) or neuraxial anesthesia may be performed for patients with functioning cerebrospinal fluid (CSF) shunts in place. In patients with increased intracranial pressure (ICP) due to poorly functioning shunts, concerns regarding anesthesia are similar to those described above. (See 'Brain tumors' above and 'Idiopathic intracranial hypertension' above.)

Shunt malfunction complicates up to 25 to 50 percent of pregnancies in women with ventriculoperitoneal shunts. This issue is discussed separately. (See "Neurologic disorders complicating pregnancy", section on 'Ventriculoperitoneal shunt'.)

For patients with lumboperitoneal shunts, there are several issues to consider in addition to shunt function.

●The spinal portion of the shunt may be disrupted during neuraxial procedures or entangled in an epidural catheter, though such complications have not been reported. The need to perform imaging to determine the exact location of the shunt if records are unavailable is unclear since the surgical scar from the shunt procedure should provide an approximate location [58].

●Spinal anesthesia may be unpredictable and of shorter duration because of local anesthetic (LA) leak via the shunt into the peritoneal cavity. An inadequate or failed block may occur [59].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Stroke in adults" and "Society guideline links: Guillain-Barré syndrome" and "Society guideline links: Obstetric anesthesia".)

SUMMARY AND RECOMMENDATIONS

●Preoperative evaluation

•Patients with neurologic disorders should have preanesthesia consultation well in advance of surgery or delivery to allow review of prior records and imaging, and to facilitate a multidisciplinary plan for perioperative or perinatal care. (See 'Timing of preanesthesia evaluation' above.)

•Patients with neurologic disorders should be assessed for the risk of brain herniation; risks of hyperkalemia, rhabdomyolysis, or malignant hyperthermia during general anesthesia (GA); potential difficulty with airway management; and the risks associated with alternatives to neuraxial anesthesia techniques. (See 'General considerations for all patients' above.)

●Patients with increased intracranial pressure

•For patients with brain tumors and other conditions associated with increased intracranial pressure (ICP) in whom neuraxial anesthesia is considered, principal concerns are the possibility of herniation of brain tissue after dural puncture, and possible risk of further increase in ICP after epidural catheter bolus. If there are clinical and radiologic signs of significant mass effect or obstruction of cerebrospinal fluid (CSF) flow, the patient is likely at high risk of brain herniation after dural puncture, and neuraxial anesthesia should generally not be performed. (See 'Neuraxial anesthesia for patients with brain tumors' above.)

•Patients with idiopathic intracranial hypertension (IIH) are not at risk for brain herniation after dural puncture during neuraxial anesthesia. Epidural boluses should be performed slowly to avoid dangerous increases in ICP. (See 'Neuraxial anesthesia for patients with IIH' above.)

●Patients with cerebrovascular disorders – For patients with untreated intracranial aneurysm or arteriovenous malformation, a primary anesthetic goal is to avoid hypertension and thereby minimize the risk of rupture of the lesion. Neuraxial analgesia and anesthesia provide hemodynamic stability and avoid the need for intubation, but dural puncture can cause intracranial hypotension and theoretically increase the risk of lesion rupture. (See 'Intracranial aneurysm and arteriovenous malformation' above.)

●Patients with multiple sclerosis – There is an increase in the relapse rate of multiple sclerosis (MS) in the postoperative and postpartum periods. Neuraxial anesthesia is not associated with an increase in MS disease activity. (See 'Multiple sclerosis' above.)

●Patients with Guillain-Barré syndrome – Succinylcholine is contraindicated in patients with neurologic deficits associated with Guillain-Barré syndrome (GBS) and for an unknown time period after recovery. Patients with GBS are extremely sensitive to nondepolarizing neuromuscular blocking agents. Autonomic dysfunction occurs in the majority of patients with acute GBS, and may cause hemodynamic instability, orthostatic hypotension, and arrhythmias. (See 'Guillain-Barré syndrome' above.)

●Patients with Chiari malformation – Patients with Chiari malformation may be at increased risk of obstruction to CSF flow between intracranial and spinal compartments, and therefore may be at risk for brain herniation after dural puncture. A wide range of spinal abnormalities is associated with Chiari malformation. (See 'Chiari malformation' above.)

●Patients with spine and spinal cord abnormalities

•These patients may be at increased risk for difficulty with airway management, difficult neuraxial anesthesia procedures, unintentional dural puncture during epidural anesthesia, and/or unpredictable or patchy neuraxial block, because of distorted anatomy or post-surgical changes. (See 'Disorders of the vertebral column and spinal cord' above.)

•Succinylcholine is contraindicated in patients with motor deficits as a result of spinal cord abnormalities because of the risk of life-threatening hyperkalemia. (See 'Disorders of the vertebral column and spinal cord' above.)

•Literature on the effects of neuraxial anesthesia on symptoms related to spinal stenosis or lumbar disc disease is inconclusive. We provide neuraxial anesthesia only after a careful documentation of the baseline neurologic deficits, symptomatology with positioning, and discussion of the risks and benefits of neuraxial techniques with the patient. (See 'Disc disease, spinal stenosis, and radiculopathy' above.)