5.2 Issues in technique
5.2.4 Outcome ofthoracoscopy for palmar hyperhidrosis
Our experience with this procedure suggests that for primary hyperhidrosis thoracoscopic sympathectomy maybe performed on a day care basis and that a limited 2nd thoracic ganglionectomy is adequate to treat palmar hyperhidrosis. Furthermore, this approach may cure axillary hyperhidrosis and more importantly, decrease the incidence of debilitating compensatory hyperhidrosis.
TI ICN
T2G
Figure 17: T2 ganglionectomy interrupts sympathetic outflow to the brachia!
plexus notwithstanding the alternate neural pathway (ANP)
C7,8,Tl VR SA
SG T2G LTBP Rl ANP T2 ICN
t\
81h cervical, I st thoracic ventral rami Subclavian arteryStellate ganglion 2nd thoracic ganglion
Lower trunk ofbrachial plexus I st rib
Alternate neural pathway 2nd intercostal nerve
For most surgeons thoracoscopic sympathectomy is a novel approach. It compels us to consider the probability of misinterpretation of the anatomy as an important cause of persistent sympathetic function. Furthermore, the teaching of the surgical anatomy of the sympathetic chain and its variations is under-emphasized during standard surgical training. In 3 patients with pSA, it was apparent that the location of the sympathetic
chain was not appreciated at the primary procedure; it is conceivable that this also occurred in the 4th patient. Fibrosis consequent to this intervention precluded a safe re
operation. In such situations, an extensive en-bloc excision of the 2nd and 3rd intercostal nerves with their spinal ganglia and surrounding tissue has been suggested as a useful option to be undertaken at open surgery (van Rhede van der Kloot and Jorning, 1990).
The authors are not comfortable with undertaking this option thoracoscopically.
Plate 29 demonstrates the potential of the fascia overlying the tendon of longus colli muscle (TLC) being misinterpreted as the sympathetic chain. The TLC lies medial to the sympathetic chain and is a much broader structure. However, with inappropriate dissection, it may easily be mistaken for the sympathetic chain.
SA SIA TlVR R2 T2ICN
Subclavian artery
Superior intercostal artery I st thoracic ventral ramus 2nd rib
2nd intercostal nerve Plate 29 : Thoracoscopic view of right proximal sympathetic chain; note TLC
mimicking the sympathetic chain
Sympathetic regeneration accounting for rSA has long been a controversial issue; whilst some authors found no evidence of regeneration at re-operation, others (Telford, 1935;
Jepson, 1951) attributed this phenomenon to rSA (Mattasi et al., 1981; Haxton 1970).
However, reports incriminating nerve regeneration have often not been accompanied by the histological evidence of nerve regeneration.
Regenerating nerve fibers establish contact between the divided ends by thin strands that may grow to the caliber of the sympathetic chain. Regeneration is only effective when the connecting neural fibers are correctly aligned. Return of sympathetic activity depends on the extent of the regenerating process and the proportion of sympathetic fibers successfully re-establishing a functional pathway. Conceivably, a greater number of sympathetic re-connections do occur but, because of inappropriate functional connections, returned sympathetic activity is subclinical. The rarity of this phenomenon underscores the difficulty of re-establishing functional sympathetic re-connections (Singh et al., 1998).
Nerve regeneration may be suspected clinically by the gradual return, over months to years, of sympathetic activity to assume the pre-sympathectomy state. This is in contrast to the presence of intact ANPs wherein the surgery does not affect sympathetic activity (Singh et al., 200 I).
Failure of effective sympathectomy is uncommon and rSA is even rarer. From the afore
mentioned findings, it is apparent that pSA is invariably a technical misadventure.
Circumvention of this pitfall necessitates appreciation of the surgical anatomy of the 2nd thoracic ganglion which is located in the 2nd intercostal space somewhat distal to the
corresponding intercostal nerve and adjacent to the superior border of the 3rd rib.
However, this ganglion has been reported to be located anterior to the 3rd rib in 15% of cases (Chiou and Liao, 1996). It is incumbent upon the surgeon to be familiar with the landmarks that assist with its identification. The 2nd intercostal nerve, located medial to the 2nd rib's posterior angle, is an under-appreciated landmark that directs to the T2 ganglion. Similarly, the superior intercostal artery (a branch of the costocervical trunk of the subclavian artery), runs an infero-Iateral course parallel to the sympathetic chain at an average distance of IO mm from the sympathetic chain. This artery ends as the 2nd intercostal artery and has been suggested to be a useful landmark (Chiou and Liao,
1996).
Electrophysiological stimulation to confirm the location (and appropriate ganglion level) of the sympathetic chain has been suggested; this expensive, time-consuming and complicated manoeuvre has, unsurprisingly, not gained wide acceptance in surgical practice (Lindquist et al., 1989).
The results presented in this study accurately reflect the outcome to sympathectomy I week following the operation; at that visit instances of early failure would have been evident. Less clear is the true incidence of late recurrence since the long-term outcome could not be evaluated in all patients. Given the potential of the sympathetic chain to regenerate, it is a moot point whether the described case in this series is truly reflective of the phenomenon.
Today, the great numbers of thoracoscopic sympathectomies undertaken have re
defined the role of ANPs. Our experience has also demonstrated the need to be
appreciative of the anatomy of the sympathetic chain. Furthermore, instances of rSA and pSA may be safely and readily treated by the thoracoscopic route (Singh et al.,
1996).