Complications Associated with Head and Neck Blocks, Upper Extremity Blocks, Lower Extremity Blocks, and Differential Diagnostic Blocks

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Chapter 12 Complications Associated with Head and Neck Blocks, Upper Extremity Blocks, Lower Extremity Blocks, and Differential Diagnostic Blocks

Collin F.M. Clarke, Pari Azari, Chang Po Kuo, Billy K. Huh

Chapter Overview

Chapter Synopsis: A diverse group of interventional techniques for chronic pain includes head and neck blocks, upper and lower extremity blocks, and differential diagnostic blocks. Although these minimally invasive procedures carry a very low risk, there are rarely catastrophic complications. The consequences vary considerably depending on the site of injection. Sites such as the trigeminal ganglion, buried inside the brain and surrounded by vasculature, pose particular anatomic challenges. Other procedures focus on sites in close anatomic proximity to structures, including nerves, brain, blood vessels, and lungs, and carry risks of particular complications depending on the affected structure.

Important Points:

Appropriate patient selection with definitive endpoints of treatment is paramount.

Procedures should only be performed by or under the direct supervision of those who have subspecialty training in interventional pain management.

Development of standardized procedural approaches, including preprocedure timeouts and sterile techniques, may decrease the likelihood of adverse events.

Thorough understanding of relevant anatomy and the ability to use imaging, whether fluoroscopy or ultrasonography, are vital to procedural success.

Although uncommon, catastrophic complications have been reported.

Complications related to the spine, major vessels, and airway may require emergent surgical intervention. Early recognition is imperative.

Introduction

As with any medical procedure, the physician performing the procedure should weigh the benefits versus the risks. Interventional procedures have significant potential benefit for those suffering from chronic pain. Although uncommon, complications may result in catastrophic outcomes. This chapter reviews the complications associated with a diverse group of procedures, including head and neck blocks, upper extremity blocks, lower extremity blocks, and differential diagnostic blocks. The complications associated with these can generally be divided into vascular, infectious, neural, pharmacologic, and anatomically related to the specific sight of injection (Table 12-1).

Table 12-1 Overview of Complications Associated with Head and Neck Block, Upper Extremity Block, Lower Extremity Block, and Differential Diagnostic Block Procedures

Vascular¹^–⁶

• Hematoma

• Airway compression

• Neural compression

• Microvascular compression

• Vascular insufficiency secondary to vasospasm

Infectious

Pharmacologic

• Cardiovascular toxicity

• High or total spinal

• Steroid

• Pituitary adrenal axis suppression

• Particulate steroid-induced vascular occlusion

Neural^2,¹⁴^–¹⁶

• Direct needle trauma

• Barotrauma from high-pressure injection

• Compression from hematoma

• Local anesthetic neural toxicity

CNS, central nervous system.

Vascular

Many neural structures are intimately connected with vasculature. Overall, the likelihood of a vascular complication is rare but potentially devastating. Reported vascular complications include airway, neural, and microvascular compression related to hematoma formation.¹^–³ Additionally, arterial dissection, pseudoaneurysm, and vascular insufficiency secondary to vasospasm have all been cited in the literature.⁴^–⁶

Infection

The likelihood of infection from any single injection is extremely rare. Infection requiring intervention after an indwelling catheter has been reported as high as 0.8%.⁷ With interventional procedures involving the neuraxis, terrible sequelae, including epidural abscess or meningitis, may occur. Evidence demonstrates that catheter insertion (particularly >48 hours), intensive care unit admission, male sex, lack of prophylactic antibiotics, and lack of provider experience increase the likelihood of infection.⁸

Local Anesthetic Toxicity

The proximity of many neural structures to major vessels predisposes itself to the potential for local anesthetic toxicity. Inadvertent vascular puncture is the most likely cause of toxicity, but it has been suggested that with no identifiable puncture, clinical doses may cause toxicity.⁹ It appears that clinically significant local anesthetic toxicity occurs between 7.5 and 20 times per 10000 regional anesthetics.¹⁰ Local anesthetic toxicity can be categorized by symptoms involving the central nervous system (CNS) and those related to cardiovascular toxicity (Table 12-2).

Table 12-2 Signs and Symptoms Associated with Local Anesthetic Toxicity

Central nervous system¹¹

• Tonic-clonic seizure

Cardiovascular¹²

• Initially hypertension and tachycardia caused by CNS excitation

• Myocardial depression

• Ventricular arrhythmias

• Conduction delays

• Profound contractile dysfunction

• Eventual cardiovascular collapse

CNS, central nervous system.

Neurologic

The likelihood of long-term neurologic injury is low, reported below 0.02%.¹³ When these injuries do occur, the outcome is often devastating to the clinician and patient alike. Nerve injury may present in a spectrum from paresthesias to paralysis, with neuropathic pain being a dreaded outcome.

Etiologies attributed to nerve injury include direct needle trauma, barotrauma from high-pressure injection, compression from hematoma, and local anesthetic neural toxicity.^2,¹⁴^–¹⁶

Complications of Head and Neck Blocks

Head and neck blocks are indispensable in management of various orofacial pain and headache syndromes. However, because of the limited space and close proximity to important structures such as arteries, nerves, brain, and lungs, there is potential for significant complications. The most common complications of head and neck procedures are related to injury to blood vessels leading to bleeding and systemic toxicity from vascular or subdural injection of local anesthetics, which can cause seizure, hemodynamic instability, or even cardiac arrest. Therefore, image-guided (fluoroscopy or ultrasonography) needle placement is highly recommended when performing procedures in the head and neck area. The collateral damage to surrounding structures from needle, radiofrequency ablation (RFA), chemical ablation, or balloon compression can vary depending on the specific anatomic location of the targets.

A variety of percutaneous techniques are available for targets at head and neck, including sphenopalatine ganglion (SPG), Gasserian ganglion, atlantoaxial joint (AAJ) and atlantooccipital joint (AOJ), stellate ganglion, and C2 dorsal root ganglion. See Table 12-3 for a description of complications associated with head and neck injections.

Table 12-3 Common Head and Neck Blocks with Associated Complications

Gasserian ganglion block and neurolysis^17,³²

• Brainstem anesthesia

• Significant bleed

• CSF leak

• Permanent trigeminal sensory loss

SPG block²⁰^–²⁴

• Cheek hematoma (most common complication)

• Epistaxis (more frequent with intranasal approach)

• Intravascular injection

• Hematoma formation within the PPF

• Reflex bradycardia is likely with RFA because of the rich parasympathetic connections to the SPG

• Permanent or temporary hyperesthesia or dysesthesia in the palate, maxilla, or posterior pharynx

• Temporary diplopia

AAJ and AOJ injections¹⁹

• Seizure secondary to vertebral artery injection

Stellate ganglion block^1,^33,³⁴

• Horner syndrome

• Recurrent laryngeal nerve block

• Vagus nerve block

• Phrenic nerve block

• Hematoma

• Airway compromise

• Disc perforation

• Esophageal perforation

• High spinal block

C2 dorsal root ganglion injection

• Total spinal block leading to a rapid decrease in blood pressure and difficulty breathing

• Nerve damage, paralysis, stroke, and even death

AAJ, atlantoaxial joint; AOJ, atlantooccipital joint; CSF, cerebrospinal fluid; PPF, pterygopalatine fossa; RFA, radiofrequency ablation; SPG, sphenopalatine ganglion.

Gasserian Ganglion Block and Neurolysis

The Gasserian (trigeminal) ganglion lies within the Meckel cave, which contains cerebrospinal fluid (CSF), and local anesthetic deposited in this area may spread to other cranial nerves and can potentially cause brainstem anesthesia.¹⁷ Infection, CSF leak, bleeding, and nerve damage are also likely with Gasserian ganglion block or ablation because it is located in the middle of the brain surrounded by blood vessels. Literature studies show that RFA of the Gasserian ganglion is associated with the highest incidence of complications, with nearly one-third of patients developing some form of complications.¹⁸ Postoperative trigeminal sensory loss affects virtually all patients treated with RFA, and it is considered a side effect rather than a complication.

Sphenopalatine Ganglion Block

Epistaxis is more frequent with an intranasal approach to SPG block; intravascular injection or hematoma formation can occur after maxillary artery injury, which lies within the pterygopalatine fossa (PPF). Cheek hematoma is the most common complication. Infection is always possible especially with inadvertent needle entry into the nasal or oral cavity.¹⁹ Reflex bradycardia is likely with RFA because of the rich parasympathetic connections to the SPG.²⁰ RFA of the SPG can result in permanent or temporary hyperesthesia or dysesthesia in the palate, maxilla, or posterior pharynx.²¹^–²³ Temporary diplopia, which is more common after local anesthetic injections rather than RFA, is caused by the spread of the injectate from the PPF to the inferior orbital fissure containing the abducent nerve.²⁴ Temporary diplopia is likely if the needle tip is deep inside the PPF and the volume of injectate is greater than 1 to 2 mL.

Atlantoaxial Joint and Atlantooccipital Joint Injections

The AAJ and AOJ are in very close proximity to the vertebral artery (Fig. 12-1). Consequently, particular attention should be paid to avoid intravascular injection because vertebral artery anatomy can be unpredictable. Intraarterial injection may cause seizure or posterior circulation stroke.²⁵ Inadvertent puncture of the C2 dural sleeve with CSF leak or high spinal spread of the local anesthetic may occur with AAJ injection if the needle is directed too medially. This can result in a rapid and profound decrease in blood pressure followed by apnea and death. Therefore, intravenous access should be established before the procedure. Spinal cord injury and syringomyelia are potential serious complications if the needle is directed even further medially.¹⁹

Fig. 12-1 The close proximity of the vertebral artery to the atlantooccipital joint (AOJ) and atlantoaxial joint (AAJ) to the vertebral artery results in a significant risk of intraarterial injection.

(Modified from Edlow BL, Wainger BJ, Frosch MP, et al: Posterior circulation stroke after C1-C2 intraarticular facet steroid injection: evidence for diffuse microvascular injury, Anesthesiology 112:1532-1535, 2010.)