The effects of clipping on thoracic sympathetic nerve in rabbits: early and late histopathological findings

Electrophysiological evaluation of efficacy of clipping in thoracic sympathectomy: An experimental cadaveric study

Background

This study aims to examine the efficacy of clipping in thoracic sympathectomy based on electrophysiological evaluation and to investigate whether nerve conduction can be formed by collateral nerve extensions as a result of the clipping procedure to different levels of sympathetic nerve.

Methods

Newly sacrificed six sheep hemithoraces were studied between August 2016 and October 2016. Thoracic sympathectomy was performed by clipping at T2, T3, T4, and T5 sympathetic chain levels and their branches. Electrophysiological studies were performed with an electromyography device and the filter range was 1 Hz with 20 μV/D amplification. Signals were processed digitally; bipolar subdermal needle electrodes were used as stimulation and recording electrodes (Ø 0.75 mm); and the ground electrode was placed in the intercostal muscle where the thoracic sympathectomy procedure would be performed.

Results

Electrophysiological evaluations showed that clips placed on the main sympathetic chain branches and sympathetic nerve trunk prevented collateral impulse conduction and stimulated potentials were not recorded. However, sympathetic conduction continued at the same intensity after removal of the clips.

Conclusion

Clipping of different regions of the sympathetic nerve provides electrophysiological blockage of the sympathetic nerve, and conduction continues after removal of the clips. However, the shortand long-term postoperative electrophysiological results after removal of the clips over the sympathetic nerve is still a question mark.

Pulsed radiofrequency stimulation suppresses palmar hyperhidrosis in an animal study

OBJECTIVES

Palmar hyperhidrosis (PH) exhibits excessive and unpredictable sweating. The most effective treatment for permanent cure is the ablation of thoracic sympathetic ganglia innervating hands. However, sympathectomy of T2 sympathetic ganglion by clipping or cauterization causes irreversible nerve damage, and results in a compensatory hyperhidrosis (CH). We herein used the pulsed radiofrequency (PRF) stimulation to reversibly block sympathetic ganglion to treat PH and avoid CH.

MATERIAL AND METHODS

A bipolar electrode was implanted into the right T2 sympathetic trunk by endoscopic surgery and PRF was delivered through the electrode. The humidity (%) of right palm was measured to indicate sweating level.

RESULTS

Six out of 13 rats (46.2%) that received a 5-min PRF stimulation on the T2 sympathetic trunk showed a decrease in the right palm humidity during the surgery. PRF stimulation significantly reduced humidity from 69.17% ± 0.72% obtained from baseline condition to 66.93% ± 0.69%. The humidity reduction was also observed at 10 min after the PRF stimulation. We further evaluated the effect of PRF stimulation 1 week after surgery and found that the PRF stimuli reduced right hand humidity in 5 out of 8 rats (62.5%). PRF stimulation significantly reduced humidity from 66.11% ± 0.81% obtained from sham operation control to 63.62% ± 0.82%. The percentage of right hand humidity obtained 10 min after PRF stimulation was also reduced to 63.38% ± 0.80%. Anesthetics have no effect on humidity.

CONCLUSIONS

These results indicate that PRF stimulation of T2 sympathetic trunk reduces palm sweating in rats.

Does endoscopic thoracic sympathectomy through clipping procedure have early effects on electrocardiographic parameters?

Background & objectives:

Hyperhidrosis is a pathologic condition of excessive sweating in amounts greater than physiologic needs. Endoscopic thoracic sympathectomy (ETS) is a globally accepted treatment modality for primary palmar and axillary hyperhidrosis. ETS also has distinctive effects on the heart, circulatory and respiratory systems. In this study early effects of ETS on electrocardiographic (ECG) parameters of hyperhidrosis patients were evaluated.

Methods:

Twelve-lead ECGs were performed on 72 patients who were free from cardiovascular, metabolic, neurological and pulmonary diseases and underwent planned ETS because of hyperhidrosis, before and after the procedure within the first 24 h. Heart rate (HR), PR, QT, corrected QT (QTc), QTc/Tpeak-Tend (TpTe) intervals, P-wave and QTc/TpTe dispersions were compared by ECG.

Results:

A total of 72 patients (24.1±6.0 yr, 17 female) were included in the study. The pre-operative HR of patients was significantly higher than post-operative HR of patients (73.8±12.8 vs. 68.1±12.6 beats/ min; P<0.001). The QTc dispersion (QTcd) durations of pre-operative patients were significantly longer than those of post-operative patients (51.5±6.3 vs. 44.9±5.6 msec; P<0.01). The TpTe dispersion value of pre-operative patients was significantly (P<0.001) higher than that of post-operative patients.

Interpretation & conclusions:

Our study showed that ETS through clipping procedure had positive effects on the mechanisms of arrhythmia by reducing HR, QTcd, TpTe and TpTe dispersion parameters of ECG in early periods in hyperhidrosis patients.

Reversibility of Sympathectomy for Primary Hyperhidrosis

Endoscopic thoracic sympathectomy (ETS) is an effective treatment of primary hyperhidrosis of the face, upper extremities, and axillae. The major limitation is the side effect of compensatory sweating severe enough that patients request reversal in up to 10% of cases. When ETS is performed by cutting the sympathetic chain, reversal requires nerve grafting. However, for ETS done with clips, reversal is a simple thoracoscopic outpatient procedure of removing the clips. Subsequent reversal of the sympathectomy, ie, nerve regeneration, is successful in many cases. However, follow-up is short. Factors contributing to success rates require further study.

Comparisons of the clinical outcomes of thoracoscopic sympathetic surgery for palmar hyperhidrosis: R4 sympathicotomy versus R4 sympathetic clipping versus R3 sympathetic clipping

BACKGROUND

Thoracoscopic sympathetic surgery is regarded as a definitive treatment for palmar hyperhidrosis. However, the optimal surgical strategy remains unclear. The aim of this study was to compare outcomes based on the level and type of sympathetic disconnection in patients with palmar hyperhidrosis.

METHODS

From January 2009 to December 2014, 101 patients with palmar hyperhidrosis underwent thoracoscopic sympathetic surgery at Gangnam Severance Hospital. Complete follow-up information was obtained from 59 patients. We retrospectively analyzed the results of operation, degree of palmar sweating (%), grade of compensatory sweating (none, mild, moderate, severe, very severe), grade of satisfaction (very satisfied, satisfied, moderate, dissatisfied, very dissatisfied), and recurrence/failure.

RESULTS

R4 sympathicotomy, R4 sympathetic clipping, and R3 sympathetic clipping were performed in 16, 20, and 23 patients, respectively. The mean degree of palmar sweating after sympathetic surgery was not significantly different between these three groups (17.50% vs. 27.00% vs. 29.78%; P=0.38). The rate of life-bothering compensatory sweating was lower in the R4 sympathicotomy group compared with those of other two groups (0% vs. 25%, 47.8%; P=0.09). The rate of very satisfied to moderate grades of satisfaction were lower in the R3 sympathetic clipping group compared with those of other two groups (93.8%, 100% vs. 73.9%; P=0.07). The rate of recurrence/failure rates were lower in the R4 sympathicotomy group compared with those of other two groups (12.50% vs. 35.00%, 34.8%; P=0.25). Sympathetic surgery at the R3 level was the only significant risk factor for patient dissatisfaction (odd ratio =12.353, 95% confidence interval =1.376-110.914; P=0.025).

CONCLUSIONS

Our data support that R4 sympathicotomy had lower grades of compensatory sweating, higher grades of satisfaction, and lower rates of recurrence/failure. We therefore consider R4 sympathicotomy as an optimal surgical treatment for palmar hyperhidrosis.

Sympathetic block by metal clips may be a reversible operation

OBJECTIVES

Thoracoscopic sympathectomy is now used routinely to treat patients with disabling primary hyperhidrosis or facial blushing. Published results are excellent, but side effects, such as compensatory sweating, are also very frequent. The surgical techniques used and the levels of targeting the sympathetic chain vary tremendously. Most surgeons transect or resect the sympathetic chain, but application of a metal clip that blocks transmission of nerve impulses in the sympathetic chain is used increasingly worldwide. This approach offers potential reversibility if patients regret surgery, but the question of reversibility remains controversial. Two recent experimental studies found severe histological signs of nerve damage 4-6 weeks after clip removal, but they only used conventional histopathological staining methods.

METHODS

Thoracoscopic clipping of the sympathetic trunk was performed in adult sheep, and the clip was removed thoracoscopically after 7 days. Following another 4 weeks (n = 6) or 12 weeks (n = 3), the sympathetic trunks were harvested and analysed by conventional and specific nerve tissue immunohistochemical stains (S100, neurofilament protein and synaptophysin). The contralateral sympathetic chains were used as controls.

RESULTS

Conventional and immunohistochemical stains demonstrated severe signs of neural damage on the operated side 4 weeks after clip removal. After 12 weeks, these changes had decreased markedly and conventional histology had almost normalized.

CONCLUSIONS

Conventional and immunohistochemical stains confirmed that application of metal clips to the sympathetic chain caused severe histological damage in the sympathetic trunk that remained visible 4 weeks after clip removal. However, after 12 weeks, these signs of damage had clearly decreased, which suggests in theory that application of metal clips to the sympathetic chain is a reversible procedure if only the observation period is prolonged. Further studies with longer periods between application and removal as well as investigations of nerve conduction should be encouraged, because we do not know whether histological reversibility at cellular level translates into physiological reversibility and possible correlation of nerve trauma with the duration of the applied clip.

Pathological alterations and stress responses near DBS electrodes after MRI scans at 7.0T, 3.0T and 1.5T: an in vivo comparative study

OBJECTIVE

The purpose of this study was to investigate the pathological alterations and the stress responses around deep brain stimulation (DBS) electrodes after magnetic resonance imaging (MRI) scans at 7.0T, 3.0T and 1.5T.

MATERIALS AND METHODS

DBS devices were stereotactically implanted into the brains of New Zealand rabbits, targeting the left nucleus ventralis posterior thalami, while on the right side, a puncture passage pointing to the same target was made. MRI scans at 7.0T, 3.0T and 1.5T were performed using transmit/receive head coils. The pathological alterations of the surrounding tissue were evaluated by hematoxylin and eosin staining (H&E staining) and transmission electron microscopy (TEM). The levels of the 70 kDa heat shock protein (HSP-70), Neuronal Nuclei (NeuN) and Caspase-3 were determined by western-blotting and quantitative polymerase chain reaction (QPCR) to assess the stress responses near the DBS electrodes.

RESULTS

H&E staining and TEM showed that the injury around the DBS electrodes was featured by a central puncture passage with gradually weakened injurious alterations. Comparisons of the injury across the groups manifested similar pathological alterations near the DBS electrodes in each group. Moreover, western-blotting and QPCR assay showed that the level of HSP-70 was not elevated by MRI scans (p>0.05), and the levels of NeuN and Caspase-3 were equal in each group, regardless of the field strengths applied (p>0.05).

CONCLUSIONS

Based on these findings, it is reasonable to conclude that in this study the MRI scans at multiple levels failed to induce additional tissue injury around the DBS electrodes. These preliminary data furthered our understanding of MRI-related DBS heating and encouraged revisions of the current MRI guidelines for patients with DBS devices.

Long-term results of endoscopic sympathetic block using the Lin-Telaranta classification

BACKGROUND

Endoscopic thoracic sympathectomy has been used successfully in the treatment of blushing, excessive sweating, and social phobia. However, the adverse effects of endoscopic thoracic sympathectomy are more severe and frequent than the adverse effects of endoscopic sympathetic block (ESB). The use of different blocking levels for different indications in ESB according to the Lin-Telaranta classification further decreases the postoperative adverse effects. However, there are few data on the long-term results of ESB performed using the Lin-Telaranta classification.

METHODS

Ninety-five patients (55 men, 40 women) were interviewed by before the surgery using our routine questionnaire, and the same questionnaire was answered postoperatively by the patients. In addition, a long-term follow-up questionnaire was sent to all patients whose address was known. Forty-seven patients (24 men, 23 women) answered to this questionnaire. The Davidson brief social phobia scale and the Liebowitz quality of life scale were used. Patients were divided to 3 categories: category 1, patients with sweating problems; category 2, patients with blushing; and category 3, and patients with symptoms other than sweating or blushing.

RESULTS

Among patients in category 1, social phobia decreased from 12.43 to 6.71 (p = 0.004), in category 2 from 13.97 to 7.69 (p < 0.001), and in category 3 from 13.18 to 9.64 (p = 0.007) during long-term follow-up. Among patients with severe sweating problems preoperatively, sweating decreased from 2.50 to 1.29 (p = 0.003) among patients in category 1 and from 1.86 to 1.16 (p < 0.001) among patients in category 2. Among patients with unbearable blushing, blushing decreased from 4 to 1.80 (p < 0.001).

CONCLUSIONS

Patients got a clear help from ESB performed using the Lin-Telaranta classification to treat blushing, excessive sweating, and social phobia with and without physical symptoms. In addition, compensatory sweating increased only slightly.