Original Thoracic

Can Thoracic Sympathetic Nerve Damage Be Reversed? M. Muharrem Erol1 Hakan Salcı2 Hüseyin Melek1 Ahmet Sami Bayram1 Cengiz Gebitekin1 1 Department of Thoracic Surgery, Uludag University, Faculty of

Medicine, Bursa, Turkey 2 Department of Surgery, Uludag University, Faculty of Veterinary Medicine, Bursa, Turkey 3 Department of Histology, Uludag University, Faculty of Veterinary Medicine, Bursa, Turkey

Tuncay İlhan3

Nesrin Özfiliz3

Address for correspondence Ahmet Sami Bayram, MD, Department of Thoracic Surgery, Uludag University, Faculty of Medicine, Gorukle Campus, 16059 Bursa, Turkey (e-mail: [email protected]).

Abstract

Keywords

► experimental ► surgery/incisions ► histology

Background Function of the thoracic sympathetic chain (TSC) reportedly recovers after surgical clips are removed. Hence, this study was designed to study nerve regeneration after unclipping the TSC. Methods The bilateral TSCs of six goats were studied; the goats were separated into three groups (groups I, II, and III) during excision, clipping, and unclipping. During surgery, the TSCs were excised with a scalpel in group I and clipped in groups II and III. In group III, the clips were removed 1 month postoperatively and observed for possible nerve healing for 1 month. All TSCs were examined histologically following en block resection at 1 month postoperatively in groups I and II and at 2 months postoperatively in group III. Results Inflammation in nerve sections was noted following clip removal. Furthermore, there was significant degeneration and cell infiltration in the nerve fibers of the clipped regions. The Schwann cells around the peripheral nerve endings in the unclipped regions facilitated nerve transmission by reconstitution of myelin. Conclusion Clipping the TSC can cause histologic degeneration; however, histologic nerve regeneration occurs after unclipping.

Introduction Thoracic sympathectomy is a treatment for patients with hyperhidrosis and pain disorders.1 Although surgical procedures can be highly invasive and can cause significant morbidity, minimally invasive thoracoscopic procedures associated with marginal postoperative morbidity have been developed that allow for detailed visualization of the sympathetic ganglia.1,2 Of these, thoracic sympathectomy is most commonly performed, but the mechanism of thoracic sympathetic chain (TSC) regeneration is still not clear. Thus, objective histologic examinations of the clipped TSC should

received July 1, 2014 accepted after revision July 31, 2014

be performed to prove the hypothesis. As such, the aim of this study was to determine whether nerve function recovers following postsurgical removal of clips from the TSC.

Materials and Methods This study was approved by the Uludağ University Ethic Committee (2012–13/02). Bilateral TSCs of 3-year-old Saanen goats (n ¼ 12), separated into three groups, were studied. Surgery was performed between the third and fourth thoracic level as follows: group I (n ¼ 4), excision of the TSC using a scalpel; group II (n ¼ 4), clipping of the TSC;

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DOI http://dx.doi.org/ 10.1055/s-0034-1390046. ISSN 0171-6425.

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Thorac Cardiovasc Surg

and group III (n ¼ 4), clipping of the TSC, followed by unclipping 1 month postoperatively and observation of healing for another month. General anesthesia was induced by xylazine HCl, ketamine HCl þ diazepam, and 2% isoflurane. Intratracheal intubation, pulse oximetry, monitoring of partial pressure of carbon dioxide by capnography, measurement of oxygen saturation, electrocardiography, and positive pressure mechanic ventilation-assisted respiration were performed during surgery. The TSCs were exposed after a bilateral fourth intercostal lateral thoracotomy. The sympathetic nerves and its branches were dissected from the surrounding tissues, and endoclips (LIGAMAX 5 Endoscopic Clip Applier, Ethicon, Somerville, New Jersey, United States) were attached to all nerve fibers (►Fig. 1). A local synthetic suture was used to facilitate identification of the clipping line during the next thoracotomy and at necropsy. The clips in group III were removed by thoracotomy at 1 month after surgery, followed by observation of nerve healing for another month. All TSCs were resected en bloc at 1 month postoperatively in groups I and II but at 2 months postoperatively in group III. Samples were fixed in 10% formalin solution. Following routine histologic techniques and Crossman trichrome staining, light microscopy was used for histologic study.

Erol et al.

Fig. 2 Significant degeneration and cell infiltration (arrows) in the clipped region of the sympathetic nerve due to pressure applied by the clips (4).

lination. Schwann cells around the peripheral nerve endings were seen in the unclipped regions, which was responsible for nerve transmission through the reconstitution of myelin.

Discussion Results Normal peripheral clusters of nerve fibers were identified superior to the excision and clipped sites. The perineurium and epineurium, consisting of myelinated and nonmyelinated nerve fibers and connective tissue elements, were seen between the fibers. Inflammation was found in the nerve sections after clip removal. Significant degeneration and cell infiltration were seen in the nerve fibers of the clipped regions because of the pressure exerted by the clips on the sympathetic nerve (►Fig. 2). Contraction and vacuolization of the nerve bunches were observed after clip removal (►Fig. 3). However, the essential problem was the presence or absence of demye-

Since first reported by Alexander in 1889,1 sympathectomies have been widely used in thoracic surgery. Although hyperhidrosis is benign, it can have serious sociologic complications that affect quality of life. During the past decade, endoscopic thoracic sympathectomy (ETS) has become popular owing to its minimally invasive and efficient technique.2,3 The other indications for ETS include Raynaud phenomenon, facial blushing, moyamoya disease, and long QT syndrome.4–7 ETS can be used bilaterally. Although one-stage surgeries are common, two-stage unilateral implementation has been shown to cause less compensatory sweating.8 Moreover, ETS can be used for clipping, cauterization, and scissor

Fig. 1 The perioperative appearance of the clipped thoracic sympathetic chain.

Fig. 3 Contraction and vacuolization (arrows) of the nerve bunches after clip removal (10).

Thoracic and Cardiovascular Surgeon

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Can Thoracic Sympathetic Nerve Damage Be Reversed?

Can Thoracic Sympathetic Nerve Damage Be Reversed?

2 Unal O, Citgez B, Battal M, Karatepe O. Single incision thoraco-

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sympathectomy. J Neurosurg 1999;91(1):90–97

scopic sympathectomy for hyperhidrosis. BMJ Case Rep 2012; 2012:2012 Hashmonai M, Assalia A, Kopelman D. Thoracoscopic sympathectomy for palmar hyperhidrosis. Ablate or resect? Surg Endosc 2001;15(5):435–441 Hashmonai M, Kopelman D. History of sympathetic surgery. Clin Auton Res 2003;13(Suppl 1):I6–I9 Suzuki J, Takaku A, Kodama N, Sato S. An attempt to treat cerebrovascular ’Moyamoya’ disease in children. Childs Brain 1975;1(4):193–206 Sung SW, Kim JS. Thoracoscopic procedures for intrathoracic and pulmonary diseases. Respirology 1999;4(1):19–29 Khan IA. Long QT syndrome: diagnosis and management. Am Heart J 2002;143(1):7–14 Ibrahim M, Menna C, Andreetti C, et al. Two-stage unilateral versus one-stage bilateral single-port sympathectomy for palmar and axillary hyperhidrosis. Interact Cardiovasc Thorac Surg 2013; 16(6):834–838 Cameron AE, Ojimba TA. Evaluation of the impact of transthoracic endoscopic sympathectomy on patients with palmar hyperhidrosis. Eur J Vasc Endovasc Surg 2004; 27(5):567 Kwong KF, Hobbs JL, Cooper LB, Burrows W, Gamliel Z, Krasna MJ. Stratified analysis of clinical outcomes in thoracoscopic sympathicotomy for hyperhidrosis. Ann Thorac Surg 2008;85(2): 390–393, discussion 393–394 Sugimura H, Spratt EH, Compeau CG, Kattail D, Shargall Y. Thoracoscopic sympathetic clipping for hyperhidrosis: long-term results and reversibility. J Thorac Cardiovasc Surg 2009;137(6): 1370–1376, discussion 1376–1377

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resection.8,9 In this study, we utilized both excision and clipping bilateral thoracotomies. ETS is associated with minimal risk. However, it is important to note that bleeding and infection are common surgical complications. In addition, compensatory sweating is the most common and specific clinical complication after ETS, with an incidence of 4 to 33%.10,11 To prevent and reduce the incidence of compensatory sweating, single-level nerve blockage rather than wide sympathetic nerve injury is recommended.10 Furthermore, clip removal could limit these complications. However, this benefit has not been histologically proven, which prompted this study. Clipping is the most common method for TSC blockage. Although most studies focus on the level at which clipping is performed, reports on clip removal are limited. In the present study, we found inflammation, vacuolization, and demyelination on histologic analysis of the clipped regions. Our results show that clipping can cause degeneration, but unclipping could result in nerve regeneration. Further histologic examinations are required to provide more concrete results and surgical solutions.

Erol et al.

Can Thoracic Sympathetic Nerve Damage Be Reversed?

Function of the thoracic sympathetic chain (TSC) reportedly recovers after surgical clips are removed. Hence, this study was designed to study nerve r...
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