So numerous are the possible variations that the outcome of a sympathectomy is unpredictable

The sympathetic pathways to the heart are extremely variable in their topography, and the diversity of arrangements encountered accounts for the morphological contradictions in the literature. So numerous are the possible variations that the outcome of a sympathectomy is unpredictable. Where denervation is incomplete, collateral sprouting and regeneration of nerves could even lead to hyperstimulation via the sympathetic pathways.
http://onlinelibrary.wiley.com/doi/10.1002/aja.1001240203/abstract

After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion undergo transneuronic degeneration

In consequence of right-sided smpathectomy at the level of C₅ it was found that in the sheep the cervical sympathetic trunk contains nerve fibres which proceed from cells situated in the first four segments of the thoracic part of the spinal cord and in the stellate ganglion. These fibres are about 85 per cent of all fibres of the sympathetic trunk. The remaining 15 per cent proceed from nerve cells situated nasally of the anterior cervical ganglion.

The spinal cord. Changes found in the segment Th1 – Th4 in sheep III and IV closely resembled those
seen in the stellate ganglion (Figures 6, 7).

2. After severing the sympathetic trunk, the cells of its origin undergo complete disintegration within
a year.

3. After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion
undergo transneuronic degeneration.
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0442.1967.tb00255.x/abstract

sympathectomy created imbalance of autonomic activity and functional changes of the intrathoracic organs

Surgical thoracic sympathectomy such as ESD (endoscopic thoracic sympathectic denervation) or heart transplantation can result in an imbalance between the sympathetic and parasympathetic activities and result in functional changes in the intrathoracic organs.
Therefore, the procedures affecting sympathetic nerve functions, such as epidural anesthesia, ESD, and heart transplantation, may cause an imbalance between sympathetic and parasympathetic activities (1, 6, 16, 17). Recently, it has been reported that ESD results in functional changes of the intrathoracic organs.


In conclusion, our study demonstrated that ESD adversely affected lung function early after surgery and the BHR was affected by an imbalance of autonomic activity created by bilateral ESD in patients with primary focal hyperhidrosis.
Journal of Asthma, 46:276–279, 2009
http://informahealthcare.com/doi/abs/10.1080/02770900802660949

important relationship among cognitive performance, HRV, and prefrontal neural function

These findings in total suggest an important relationship among cognitive performance, HRV, and prefrontal neural function that has important implications for both physical and mental health. Future studies are needed to determine exactly which executive functions are associated with individual differences in HRV in a wider range of situations and populations.
http://www.ncbi.nlm.nih.gov/pubmed/19424767

Low HRV is a risk factor for pathophysiology and psychopathology

The intimate connection between the brain and the heart was enunciated by Claude Bernard over 150 years ago. In our neurovisceral integration model we have tried to build on this pioneering work. In the present paper we further elaborate our model. Specifically we review recent neuroanatomical studies that implicate inhibitory GABAergic pathways from the prefrontal cortex to the amygdala and additional inhibitory pathways between the amygdala and the sympathetic and parasympathetic medullary output neurons that modulate heart rate and thus heart rate variability. We propose that the default response to uncertainty is the threat response and may be related to the well known negativity bias. We next review the evidence on the role of vagally mediated heart rate variability (HRV) in the regulation of physiological, affective, and cognitive processes. Low HRV is a risk factor for pathophysiology and psychopathology. Finally we review recent work on the genetics of HRV and suggest that low HRV may be an endophenotype for a broad range of dysfunctions.
http://www.ncbi.nlm.nih.gov/pubmed/18771686

cognition and reward processing

Recent functional magnetic resonance imaging (fMRI) investigations of the interaction between cognition and reward processing have found that the lateral prefrontal cortex (PFC) areas are preferentially activated to both increasing cognitive demand and reward level. Conversely, ventromedial PFC (VMPFC) areas show decreased activation to the same conditions, indicating a possible reciprocal relationship between cognitive and emotional processing regions. We report an fMRI study of a rewarded working memory task, in which we further explore how the relationship between reward and cognitive processing is mediated. We not only assess the integrity of reciprocal neural connections between the lateral PFC and VMPFC brain regions in different experimental contexts but also test whether additional cortical and subcortical regions influence this relationship. Psychophysiological interaction analyses were used as a measure of functional connectivity in order to characterize the influence of both cognitive and motivational variables on connectivity between the lateral PFC and the VMPFC.

These findings provide evidence for a dynamic interplay between lateral PFC and VMPFC regions and are consistent with an emotional gating role for the VMPFC during cognitively demanding tasks. Our findings also support neuropsychological theories of mood disorders, which have long emphasized a dysfunctional relationship between emotion/motivational and cognitive processes in depression.
http://dl.acm.org/citation.cfm?id=1480468

depression that may occur as part of stress system dysfunction

Stress precipitates depression and alters its natural history. Major depression and the stress response share similar phenomena, mediators and circuitries. Thus, many of the features of major depression potentially reflect dysregulations of the stress response. The stress response itself consists of alterations in levels of anxiety, a loss of cognitive and affective flexibility, activation of the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system, and inhibition of vegetative processes that are likely to impede survival during a life-threatening situation (eg sleep, sexual activity, and endocrine programs for growth and reproduction). 
http://www.nature.com/mp/journal/v7/n3/full/4001032a.html

Limbic-cortical dysregulation: a proposed model of depression

A working model of depression implicating failure of the coordinated interactions of a distributed network of limbic-cortical pathways is proposed. Resting state patterns of regional glucose metabolism in idiopathic depressed patients, changes in metabolism with antidepressant treatment, and blood flow changes with induced sadness in healthy subjects were used to test and refine this hypothesis. Dorsal neocortical decreases and ventral paralimbic increases characterize both healthy sadness and depressive illness; concurrent inhibition of overactive paralimbic regions and normalization of hypofunctioning dorsal cortical sites characterize disease remission. Normal functioning of the rostral anterior cingulate, with its direct connections to these dorsal and ventral areas, is postulated to be additionally required for the observed reciprocal compensatory changes, since pretreatment metabolism in this region uniquely predicts antidepressant treatment response. This model is offered as an adaptable framework to facilitate continued integration of clinical imaging findings with complementary neuroanatomical, neurochemical, and electrophysiological studies in the investigation of the pathogenesis of affective disorders.
http://neuro.psychiatryonline.org/cgi/content/short/9/3/471

ELECTRICAL STIMULATION OF THE SYMPATHETIC NERVE CHAIN

The present invention provides a method of affecting physiological disorders by stimulating a specific location along the sympathetic nerve chain. Preferably, the present invention provides a method of affecting a variety of physiological disorders or pathological conditions by placing an electrode adjacent to or in communication with at least one ganglion along the sympathetic nerve chain and stimulating the at least one ganglion until the physiological disorder or pathological condition has been affected.

[0009] A number of treatment regiments utilizing electrical stimulation can be employed for a vast array of physiological disorders or pathological conditions associated with the sympathetic and parasympathetic nervous system. Physiological disorders that may be treated include, but are not limited to, hyperhydrosis, complex regional pain syndrome and other pain syndromes such as headaches, cluster headaches, abnormal cardiac sympathetic output, cardiac contractility, excessive blushing condition, hypertension, renal disease, heart failure, angina, hypertension, and intestinal motility disorders, dry eye or mouth disorders, sexual dysfunction, asthma, liver disorders, pancreas disorders, and heart disorders, pulmonary disorders, gastrointestinal disorders, and biliary disorders. The number of disorders to be treated is limited only by the number, variety, and placement of electrodes (or combinations of multiple electrodes) along the sympathetic nervous system.

http://www.faqs.org/patents/app/20110098762

changes in the intracranial vascular bed due to the leakage and disappearance of the noradrenaline transmitter from the degenerating nerve terminals followed by denervation supersensitivity

The intracranial pressure, measured as the ventricular fluid pressure (VFP), was recorded continuously during about 2 days via a cannula inserted into the left lateral ventricle of the brain of conscious rabbits. The effect of bilateral removal of the superior cervical ganglia on the VFP was studied at various time-periods after operation, and the results were compared with those from unoperated control animals. The pressure changes attributed to the sympathectomy are referred to as the net VFP. The operation ultimately caused a disappearance of noradrenaline from intracranial sympathetic nerves. The net VFP was not affected during an 8-hr period of the recording starting 5–8 hrs after sympathectomy. During the following 35 hrs it was reduced by approximately 25 mm physiological saline followed by a return to initial or somewhat higher levels. Four days after sympathectomy the net VFP was significantly increased throughout the recording period. Two weeks after the operation the pressure had returned to the same, or even lower level compared with the non-sympathectomized control animals. The variations in the net VFP at different time-periods after sympathectomy are considered to reflect mainly changes in the intracranial vascular bed due to the leakage and disappearance of the noradrenaline transmitter from the degenerating nerve terminals followed by denervation supersensitivity. The results are discussed in terms of a sympathetic influence on the intracranial pressure mediated through the volume of the intracranial vascular bed, and/or the cerebrospinal fluid production in the choroid plexuses.
http://onlinelibrary.wiley.com/doi/10.1111/j.1748-1716.1971.tb05049.x/abstract

Endoscopic sympathetic block--new treatment of choice for social phobia?

Ann Chir Gynaecol. 2001 ;90 (3):177-84  11695789  Cit:3

Central neural integration for the control of autonomic responses associated with emotion

http://www.ncbi.nlm.nih.gov/pubmed/6370083
http://www.google.com./search?q=neural+integration+for+the+control+of+autonomic+responses+associated+with+emotion&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

ganglion block for unbalanced sympathetic nervous system disorders

Stellate ganglion blocks (SGB) are widely used for pain relief in outpatient clinics due to its many therapeutic indications and easy maneuvering. It is used locally over stellate ganglion territory disorders in the craniocervical (head and neck) or upper limbs and systemically for angina pectoris, psychosomatic disorders, hormonal disorders, or unbalanced sympathetic nervous system disorders [1].
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872892/

sympathectomy can result in spinal cord infarction

Uncommon causes include decompression sickness, which has a predilection for spinal ischemic damage; complications of abdominal surgery, particularly sympathectomy;...

http://www.neurology-asia.com/Spinal_Cord_Infarction.php

For blood pressure control in certain acute hypotensive states (e.g., pheochromocytomectomy, sympathectomy...

Norepinephrine (Levophed ®) -
For blood pressure control in certain acute hypotensive states (e.g., pheochromocytomectomy, sympathectomy, poliomyelitis, spinal anesthesia, myocardial infarction, septicemia, blood transfusion, and drug reactions).
http://www.globalrph.com/norepinephrine_dilution.htm