Current Role of Sympathectomy (Upper and Lower)

Sympathetic Ganglia

The motor sympathetic route is formed by three neurons ( Fig. 193.1 ). The cell body of the first neuron is located in the sudomotor and vasomotor centers, mainly in the hypothalamus. Its axon projects along the dorsal longitudinal and spinovestibular fascicles to the cell body of the second neuron (preganglionic neuron), which is located in the intermediolateral nucleus of the spinal gray matter, between the first thoracic and second lumbar vertebrae. Its axon (the preganglionic fiber) exits the medulla through the ventral root of the spinal nerves and, through the white communicating branch, projects to the paravertebral ganglion, where it forms a synapse with the cell body of the third neuron, the postganglionic neuron. Its axon (the postganglionic fiber) leaves the sympathetic chain through the gray communicating branch into the spinal nerve and is distributed peripherally. The ganglia are also interconnected longitudinally by axons from preganglionic neurons that run rostrally or caudad to the neighboring ganglia of the chains.

As in the somatic nervous system, the axon of the preganglionic neuron exits the segment in which its soma is located. There is one sympathetic paravertebral ganglion (G) for each spinal segment. The sympathetic fiber that originates from the ganglion innervates the area of the spinal nerve corresponding to that segment. Thus the second ganglion (G2) supplies sympathetic innervations for the structures of the second dermatome (D2).

In the neck, there are normally three ganglia in the sympathetic chain. The superior cervical ganglion results from the fusion of the first four sympathetic cervical ganglia; it is located at the level of the transverse process of the second and third cervical vertebrae and supplies the head and neck. The middle cervical ganglion is located at the level of the sixth cervical vertebra. The inferior cervical ganglion is generally fused with the first thoracic ganglion (G1) to form the cervicothoracic ganglion (stellate ganglion), which is located anterior to the head of the first rib and covered by the pleura.

In the thoracic region, the ganglia of the sympathetic chain are positioned anteriorly to the transverse processes of the thoracic vertebrae and are covered by the parietal pleura. They are fewer in number than the spinal thoracic nerves because of the fusion of the first thoracic ganglion with the inferior cervical ganglion, fusion of the last thoracic ganglion with the first lumbar ganglion, and fusion of the thoracic ganglia with each other.

The greater, lesser, and least splanchnic nerves are formed by preganglionic fibers originating from the 5th to 12th thoracic medullary segments. They cross the corresponding sympathetic ganglia without forming synapses with them and end in the celiac, aorticorenal, and superior and inferior mesenteric ganglia. The major splanchnic nerve plays a particularly important role in visceral pain because of the large numbers of visceral afferent fibers it contains. Hence splanchnicectomy may be employed to treat unmanageable visceral pain, particularly in pancreatic diseases (cancer and pancreatitis). In the past, thoracolumbar sympathectomies were performed to treat hypertension, a technique currently abandoned with the advent of modern antihypertensive drugs.

Sympathetic Innervation of the Upper Limbs

The preganglionic fibers responsible for the innervation of the upper limbs originate from the second to eighth thoracic medullary segments, most of them below the fourth segment. The fibers enter the paravertebral sympathetic chain through the white communicating branches of the corresponding ganglia and have an ascending pathway in which a synapse is formed with cells located in the second thoracic ganglion, the stellate ganglion, and probably the middle cervical ganglion. It is of surgical interest that no preganglionic fibers enter the sympathetic chain above the first thoracic ganglion, which participates in innervation of the limb in only 10% of the cases.

In most patients, the thoracic sympathetic trunk is located in the middle of the intercostal space, on the bottom edge of the top rib or the top edge of the bottom rib. Therefore when one sections the sympathetic chain on two consecutive ribs, there is a high probability that one is making the sympathetic ganglion between them dysfunctional.

Several anatomic landmarks have been used to determine the exact location of sympathetic interruption, including the thoracic ganglion (G), the vertebral level, and the intercostal space. More recently, a rib-oriented nomenclature has been suggested that refers to the rib level (R) instead of the vertebral level for sympathetic interruption. This decision was based on too many patients having mediastinal fat that can obscure clear identification of the specific ganglia and because there are many anatomic variations in the ganglion anatomy. Information about the technique used for ganglionic interruption should also be included in the nomenclature, stating whether clipping, cauterization, or segment removal is performed. For this chapter, we use the ganglionic level as anatomic reference.

Sympathetic Innervation of the Lower Limbs

Sympathetic preganglionic fibers responsible for the innervation of the lower limbs originate from the 12th thoracic medullary segment to the 2nd lumbar segment and reach the sympathetic chain by white rami communicantes, all having descendant paths.

Postganglionic fibers originate in cells of the lumbar and sacral ganglia. The fibers destined for the lumbar plexus come from the first three lumbar ganglia and those destined for the sacral plexus come from the fourth lumbar nerve and sacral ganglia. Therefore, all postganglionic fibers that follow the sciatic nerve originate on ganglia located under the third lumbar nerve, since the greater number of synapses occur on the fourth lumbar nerve.

It is known that there are no rami communicantes under the second lumbar ganglion; therefore, the removal of the second and third lumbar sympathetic ganglia interrupts all preganglionic fibers to the sciatic nerve and consequently to the cutaneous territory located under the knee except the saphenous nerve territory, which originates from the lumbar plexus. To obtain thigh denervation it is necessary to remove the first lumbar ganglion. The removal of the fourth lumbar ganglion does not amplify the scope of denervation but interrupts the many postganglionic fibers destined for the sciatic nerve.

Sympathetic Innervation of the Ocular Structures

The sympathetic preganglionic fibers controlling the smooth muscles of the eye are rostral, from anterior roots of G1 and G2. The fibers enter the sympathetic chain by the corresponding ganglia but do not form synapses. The synapses are subsequently formed when they ascend to the superior cervical ganglion. The postganglionic fibers head toward the ocular–pupillary apparatus through the carotid plexus. Consequently resection of the stellate ganglion causes Horner syndrome (enophthalmos, myosis, and palpebral ptosis).

Sympathetic Innervation of the Cephalic Segment

Sympathetic innervation of the head and neck originates from the first to fifth thoracic medullary segments. The preganglionic fibers ascend the sympathetic chain and form synapses with the first thoracic ganglion and the inferior cervical ganglion. Most of the postganglionic fibers responsible for innervation of the face originate from G2, which implies that craniofacial sweating diminishes through G2 ablation.

Sympathetic Innervation of the Heart

Sympathetic innervation of the heart is supplied from the higher three heart nerves (superior, medial, and inferior) arising from the three cervical ganglia and from the sixth or seventh thoracic paravertebral ganglia. Most fibers converge at the cardiac plexuses. These nerves are more abundant in the fourth and fifth thoracic segments than at higher levels.

Idiopathic Hyperhidrosis

Hyperhidrosis, the production of excessive quantities of sweat believed to be the result of stimulation of the sympathetic nervous system at the central level, occurs mainly in the palms of the hands, armpits, soles of the feet and face, but it can also affect the abdomen, chest, back, inguinal regions and lower limbs in a symmetric manner. Hyperhidrosis manifests frequently in more than one site. Only 15% of patients have a single site of excessive sweating. The main complaint is palmar sweating. When there are two sites of sweating, the most frequent combination is palmo-plantar, and when there are three, the most frequent combinations are palmo-planto-axillary and axillary-palmo-plantar. In the literature, authors always refer to the type of patient complaint based on the site with the highest interference, regardless of the secondary sites, but we must keep in mind that in most cases the manifestations are multiple. Hyperhidrosis has unknown etiology, may arise during childhood, but it is more intense during adolescence, a transitional period of life with potential psychological stress associated with triggers of hormonal and sexual maturation. It may persist into adulthood but decreases in intensity in some patients.

Hyperhidrosis affects approximately 3% of the population; in 13% to 57% of patients it can be associated with a family history of hyperhidrosis. ^, Climate is not an etiologic factor, but hot weather exacerbates sweating.

Palmar hyperhidrosis generally takes on greater clinical significance than the others because it creates significant problems within the educational, social, professional, and affective spheres, which can worsen any emotional issues that may already exist for such patients. ^,

Plantar hyperhidrosis is frequently associated with palmar or axillary hyperhidrosis and is worsened by the use of closed shoes, which hinder evaporation and favor skin maceration. The constant dampness provides additional conditions for malodorous fungal or bacterial infections.

Axillary hyperhidrosis tends to appear at puberty, with the increased production of sexual hormones. Symptoms of axillary hyperhidrosis are disabling both professionally and socially for almost all patients who seek surgical treatment. Likewise, craniofacial hyperhidrosis and facial rubor may cause social phobia.

Nonsurgical treatment should initially be attempted in all cases of hyperhidrosis. If results are inferior to patient expectations, sympathectomy should be considered. Besides oxybutynin, other consistent alternatives include botulinum toxin injection and glycopyrrolate. Sympathectomy is indicated for patients who do not experience an improvement in quality of life despite appropriate nonoperative treatment and are willing to accept the risks involved in surgical treatment (mainly compensatory hyperhidrosis).

Ischemia of the Hand

Selected patients with ischemic hand pain or finger ulcers, particularly those with TAO and distal arterial obstruction, may benefit from sympathectomy (see Ch. 139 , Thromboangiitis Obliterans). ^{, ,} Cervicodorsal sympathectomy has been used selectively in cases of critical hand ischemia to improve cutaneous vasodilation, control ischemic rest pain and vasomotor phenomena, and support healing of the skin in patients unresponsive to conservative management. However, no randomized trial comparisons with other treatments are available, and because the disease can be improved by smoking cessation, it is difficult to judge the benefit of sympathectomy from published studies.

Complex Regional Pain Syndrome

CRPS, also known as causalgia, reflex sympathetic dystrophy (RSD), posttraumatic pain syndrome, shoulder–hand syndrome, and Sudeck atrophy, is a term that has been used since 1994. It describes a regional pain condition that often occurs after injury, is disproportionate to the inciting event, and is associated with signs of vasomotor dysfunction and sudomotor activity. When CRPS is left untreated, hyperalgesia, allodynia, signs of vasomotor dysfunction, and edema can be seen initially. After 3 to 6 months, there is increased pain, and sensory dysfunction and motor or trophic changes (or both) develop (dystrophic stage). Finally the pain decreases, but there are still sensory disturbances (atrophic stage). ^, Sympathetic blockade with local anesthesia has been used to control pain in selected patients. If it is effective, this technique can be repeated, together with physical therapy to recover functionality of the limb. Peridural or intrathecal infusions of anesthetic drugs can be used in selected patients who do not respond to conservative treatment. Because of proximity to receptor sites, the therapeutic effect of intrathecal drug application lasts longer and the rate of systemic side effects is reduced. However, there are catheter-related technical problems, such as catheter dislocation, obstruction, kinking, and disconnection or rupture, as well as drug-related side effects.

Spinal cord stimulation is efficacious in CRPS type I that is resistant to medication or other treatments. High-frequency transcutaneous electrical nerve stimulation and repetitive transcranial magnetic stimulation are noninvasive and suitable as preliminary or add-on therapies and provide satisfactory pain relief to many patients, including those resistant to medication or other therapies.

Chemical sympathectomy with phenol or alcohol seems to have at best a temporary effect limited to cutaneous allodynia. Because studies reported to date include few patients and poorly defined outcomes, well-designed studies on the effectiveness of the procedure are needed. ^,

Sympathectomy can be used in selected patients who do not respond to nonsurgical treatment or in those who have good but transient benefit from pharmacologic sympathetic blockade.

Long QT Syndrome

Long QT syndrome is an idiopathic congenital disorder of ventricular repolarization, with prevalence of at least 1 in 2000 live births, characterized by a lengthened QT interval on the electrocardiogram associated with a high incidence of severe tachyarrhythmia, syncope, and sudden death. It often occurs at a young age. There is no clinical or radiologic evidence of heart disease. Severe episodes typically occur during intense physical exercise or emotional crises, which leads to the supposition that the sympathetic nervous system plays an active part in the genesis of the problem. The mortality rate in untreated patients reaches as high as 78%. Beta-blockers are effective in preventing such crises in 75% to 80% of the cases. Sympathectomy is only potentially indicated in patients who, even with appropriate clinical treatment, continue to have syncopal crises (about 20%–25% of these patients). ^,

Raynaud Syndrome

Raynaud disease and phenomenon are exaggerated responses to cold temperature or emotional stress characterized by episodic spasm of arterioles, usually in the digits, with intermittent pallor or cyanosis, precipitated by exposure to cold, emotional upset, or drugs. The treatment of Raynaud syndrome is essentially nonoperative. Sympathectomy has been used in few patients who, despite adequate clinical treatment, continue to have severe symptoms or trophic lesions with poor healing. However, it is difficult to judge the benefit because randomized trials have not been performed and the natural history is variable.

Open Surgery for Cervicothoracic Sympathectomy

Until the 1990s and before VATS, open surgery was the “gold standard” for cervicodorsal sympathectomy. Several approaches are available for open surgery, each with its own advantages and disadvantages. There are three main approaches, the paravertebral, transthoracic, and supraclavicular routes. Today the open technique is indicated only when VATS cannot be accomplished for technical reasons or an associated open operation is being performed.

The paravertebral route, mainly used by neurosurgeons, offers wide exposure of the sympathetic chain. However, it involves extensive dissection and the sectioning of several muscle bunches and requires a long period of recovery.

The transthoracic axillary approach has the advantages of superior exposure, easier access to the sympathetic chain for wide incisions, lower risk of Horner syndrome, and good cosmetic results. The main complication is postsympathetic neuralgia, which is long-lasting and extends the recovery time.

The supraclavicular approach requires an extrapleural access and thus allows the procedure to be completed bilaterally in a single operation. The resulting scar becomes virtually invisible in a short time, convalescence is fast with little pain, hospital stay is short, and surgical complication rates are low. The disadvantage is that the stellate ganglion is the point of reference for identifying the sympathetic chain, and its simple manipulation can result in Horner syndrome, although in most cases transitory.