The amount of compensatory sweating depends on the patient, the damage that the white rami communicans incurs, and the amount of cell body reorganization in the spinal cord after surgery.
Other potential complications include inadequate resection of the ganglia, gustatory sweating, pneumothorax, cardiac dysfunction, post-operative pain, and finally Horner’s syndrome secondary to resection of the stellate ganglion.
www.ubcmj.com/pdf/ubcmj_2_1_2010_24-29.pdf

After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion undergo transneuronic degeneration
After severing the sympathetic trunk, the cells of its origin undergo complete disintegration within a year.

http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0442.1967.tb00255.x/abstract

Sunday, January 25, 2009

THE SYMPATHETIC NERVOUS SYSTEM AS A HOMEOSTATIC MECHANISM

The responses of intact rats to cold-exposure (4°C) include vasoconstriction, piloerection, shivering, adrenocorticotrophin (ACTH) hypersecretion and increased mobilization of free fatty acids and glucose. Adrenal demedullation prevents the increased mobilization of glucose and decreases survival time. Chemical sympathectomy blocks all of the responses except ACTH hypersecretion. Such animals lose body heat rapidly and die in a few hours. Total adrenalectomy has a similar effect. The damaging actions of chemical sympathectomy are reversed by administration of catecholamines while those of total adrenalectomy are reversed by cortisone. Thus, the sympathetic nervous system appears to be essential for existence at low environmental temperature.

http://jpet.aspetjournals.org/cgi/content/abstract/157/1/103

All possible side effects should be dealt with and written informed consent required

Thoracoscopic sympathicotomy by electrocautery is an irreversible procedure. Thus the indications must be meticulously considered before the final decision to operate is taken by both the surgeon and the patient. All possible side effects should be dealt with and written informed consent required.

http://www3.interscience.wiley.com/journal/106568639/abstract?CRETRY=1&SRETRY=0

Published Online: 2 Dec 2003

Copyright © 2002 Taylor and Francis Ltd

Sympathectomy impairs temperature homeostasis, decreases Cardiac output and myocardial work

The decrease in body temperature associated with the onset of central neuraxial block has three reported mechanism: loss of the patient's thermorgulatory capability, with impaired shivering and loss of the ablility to sense cold temperatures; sympathectomy induced peripheral vasodilation, resulting in admixing of peripheral (cool) with core (warm) blood (this mixing results in a 1C to 2C decrease in core temperature and is proporitonal to the extent of sympathetic block and patient's age, and loss of tissue heat below the level of sympathectomy due to vasodilation.

Neuraxial anesthesia decreases afterload by producing arterial vasodilation. This vasodilation however is not equivalent in all vascular beds. For instance, muscle and skin blood flow may be decreased by sympathectomy, whereas the total blood flow to the same extremity may be quadrupled. Additionally, the extent to which afterload is decreased by sympathetic denervation varies considerably from one patient to another.

The effectiveness of this reflex vasoconstriction in maintaining normotension is a function of the extent of the sympathetic block. If, for instance, sympathetic block reaches the fourth thoracic dermatome (T4) or higher, the intact upper limb vasculature may contribute only 5% of the total cardiac output. Even maximal vasoconstriction will be insuffiecient to compensate for the profound arterial vasodilation in the rest of the body.

Cardiac Function
Importantly, bradycardia during high (thoracic) levels of spinal or epidural anesthesia is due to two main factors: denervation of preganglionic cardiac accelerator fibers (T1-4) and diminished venous return to the right ventricle because of decreases in preload.

Cardiac Output
The extent of CO decrease is also a function of the degree of sympathetic denervation.
Conversely, assumption of an even slight head-up position during neuraxial anesthesia with high levels of sympathetic denervation (..) may have catastrophic consequences such as profound bradycardia, cerebral hypoperfusion and carida arrest. Reports of severe complications related to improper positioning of patients during high levels of spinal or epidural anesthesia have spanned the last six decades.

Myocardial Work
The significant decrease in myocardial work is due primarily to threee factors: Decrease in HR (heart rate), decrease in arterial/total peripheral resistance (afterload), and decrease in stroke volume of the left ventricle secondary to the decreased preload.

Supplemental Oxygen
The purpose of the supplemental oxygen is to assure that tissue oxygenation is maintained , despite decreases in CO and periperal blood low.

Complications in Anesthesiology
By Emilio B. Lobato, Nikolaus Gravenstein, Robert R. Kirby
Contributor Emilio B. Lobato, Nikolaus Gravenstein, Robert R. Kirby
Edition: 3, illustrated
Published by Lippincott Williams & Wilkins, 2007
ISBN 0781782635, 9780781782630

Shivering - a normal response during fever is eliminated by sympathectomy

During fever pyrogen is released from leucocytes and this agent causes the disturbed thermoregualtion (Atkins, 1960). For this response to occur, an intact efferent sympathetic system is required because fever can be markedly reduced by bilateral sympathectomy in the cat (Pinkston, 1935). In man, pyrogen seems to act above the level of the 5th cervical spinal cord segment; for a patient with a lesion at that level the intravennours administration of pyrogen produced shivering in normally innervated muscles only and no alteration in hand blood flow was seen (Cooper at al., 1964)

The Autonomic Nervous System: An Introduction to Basic and Clinical Concepts
By Otto Appenzeller, Emilio Oribe
Edition: 5, illustrated
Published by Elsevier Health Sciences, 1997
ISBN 0444827617, 9780444827616

Gustatory sweating occurred in 38% of patients, and 16% of patients regretted the operation

Follow-up by questionnaire was possible in 94% of patients after a median of 26 months. Compensatory sweating occurred in 89% of patients and was so severe in 35% that they often had to change their clothes during the day. The frequency of compensatory sweating was not significantly different among the three groups, but severity was significantly higher after Th2-4 sympathectomy for axillary hyperhidrosis (p = 0.04). Gustatory sweating occurred in 38% of patients, and 16% of patients regretted the operation.

http://ats.ctsnetjournals.org/cgi/content/abstract/78/2/427

Ann Thorac Surg 2004;78:427-431
© 2004 The Society of Thoracic Surgeons

Sympathectomy only as a last resort?

Endoscopic thoracic sympathectomy is still practiced here but its use is decreasing and it's really only advocated as the last resort for palmar [hand] hyperhidrosis or facial blushing, and it's only rarely used for axillary [underarm] hyperhidrosis.
Dr Goodman, Melbourne, Australia
http://www.sweathelp.org/english/CMN_Article.asp?ArticleCode=64750038&EditionCode=77446114
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