Inferior Trunk Research Articles

A new pipefish, Stigmatopora narinosa (Syngnathidae) from South Australia

2 Inshore Fish Group, www.ifg.bioteck.org Abstract Browne, R.K. and Smith, K. 2007. A new pipefi sh, Stigmatopora narinosa (Syngnathidae) from South Australia. Memoirs of Museum Victoria 64: 1-6. A new species of pipefi sh, Stigmatopora narinosa sp. nov. (Teleostei, Syngnathidae) is described from Gulf St. Vincent and Spencer Gulf, South Australia. S. narinosa shares with the other three described Stigmatopora species a similar fi n placement, fully enclosed brood pouch, superior and inferior trunk and tail ridges continuous, a lateral trunk ridge ending midlaterally. S. narinosa, S. nigra Kaup, 1853, and S. argus Richardson, 1840, have long prehensile tails and all Stigmatopora lack caudal fi ns. S. narinosa is most similar in meristics to S. nigra in having the dorsal fi n initiating on about the fi fth to seventh trunk ring and the lateral trunk ridge terminating across the second tail ring. In other Stigmatopora species the dorsal fi n originates on the ninth to thirteenth trunk ring, the lateral trunk ridge terminates between the eighth to thirty-second tail ring, S. narinosa is distinguished from sympatric S. nigra in having nine (range, 8.2-9.8), rather than six sub-dorsal tail rings (range, 4.8-7.1), a greater number of sub-dorsal tail and total rings, a greater number of dorsal-fi n rays, a shorter laterally fl attened and dorsally elevated snout, a distinct banded pattern in both live and preserved specimens, a larger brood number and a double layer of eggs in the brood pouch. The brood pouch is under the anterior portion of the tail and extends for 15-18 rings from the anal ring; pouch plates are absent or vestigial, and the folds of the semi-pouch enclosure meet on the ventral midline. The eggs are deposited in up to two layers, one lining the dorsum of the pouch and the other separated by a membranous partition, and the brood of up to 98 eggs is larger than the maximum number of 41 found in S. nigra and S. argus. S. narinosa young at birth are approximately 18 mm, S. nigra 13 mm, and S. argus 32 mm total length. S. narinosa has a very restricted known range and habitat, inhabiting patchy open beds of sea-grasses with brown algae on sandy rubble substrate between 1 m and 5 m depth over less than 200 km of coastline.

The surgical anatomy of the ansa pectoralis

Detailed anatomical knowledge of the pectoral nerves is of clinical importance in surgeries as diverse as limb neurotization, mastectomy, orthopedic procedures and operations related to trauma. The brachial plexus of 200 cadavers were examined in an attempt to clarify the normal origins, courses and variations of the nerves with special emphasis on the ansa pectoralis (AP). In 75% the MPN arose from the anterior division of the inferior trunk of the brachial plexus and in 25% it arose from the medial cord. In 40% of specimens, the LPN arose from a single contributing nerve (anterior division of the superior trunk, 11%; anterior division of the middle trunk 18%; lateral cord, 11%). In the remaining 60% of specimens, the LPN arose from the fusion of two rootlets derived variably from the anterior divisions of the superior and middle trunks and the lateral cord. A single AP was found to be present bilaterally in 200 (100%) of the specimens. Classification of the AP was based upon its origin from the upper or lower rootlet of the LPN, the LPN itself, or from the deep branch of the LPN. AP-1 (42%) arose from the deep branch of the LPN; AP-2 (28%) arose directly from the LPN; AP-3 (25%), arose from the lower rootlets of the LPN and rarely, the AP arose from the upper rootlet of the LPN and crossed posterior to the lower rootlet to communicate with the MPN (AP-4, 5%). Irrespective of the aforementioned types, the AP was found to be present, crossing the second segment of the axillary artery in 90% of the specimens. These results could prove useful during the preoperative planning of neurotization and other surgical procedures involving the axilla.

Common Trunk of the Inferior Pulmonary Veins in a Patient with Paroxysmal Atrial Fibrillation

Herein we report a case of a patient presenting with paroxysmal atrial fibrillation (PAF) in whom the pulmonary veins (PVs) had a common inferior trunk and PV isolation at the common inferior trunk was successfully performed to prevent recurrence of PAR A 58-year-old man with drug-resistant PAF was referred to undergo curative treatment at our institution. A three-dimensional image of the PVs re-constructed by contrast-enhanced multi-detector computed tomography before the operation revealed a common inferior trunk of the PVs (24mm diameter). Segmental ostial PV isolation with the guidance of a circular mapping catheter was performed for both superior PVs and the common inferior PV trunk. All three PV ostia were successfully isolated from the LA, and the patient has been free from PAF thereafter for 18 months. Preprocedural multi-detector computed tomography or magnetic resonance imaging to evaluate the anatomy of PVs (the number, size, and shape) is thus considered to be useful for performing safe and smooth catheter ablation in patients with PAR

Common Trunk of the Inferior Pulmonary Veins in a Patient with Paroxysmal Atrial Fibrillation

Herein we report a case of a patient presenting with paroxysmal atrial fibrillation (PAF) in whom the pulmonary veins (PVs) had a common inferior trunk and PV isolation at the common inferior trunk was successfully performed to prevent recurrence of PAR A 58-year-old man with drug-resistant PAF was referred to undergo curative treatment at our institution. A three-dimensional image of the PVs re-constructed by contrast-enhanced multi-detector computed tomography before the operation revealed a common inferior trunk of the PVs (24mm diameter). Segmental ostial PV isolation with the guidance of a circular mapping catheter was performed for both superior PVs and the common inferior PV trunk. All three PV ostia were successfully isolated from the LA, and the patient has been free from PAF thereafter for 18 months. Preprocedural multi-detector computed tomography or magnetic resonance imaging to evaluate the anatomy of PVs (the number, size, and shape) is thus considered to be useful for performing safe and smooth catheter ablation in patients with PAR

Microsurgical anatomy of the insula and the sylvian fissure.

The purpose of this study was to define the topographic anatomy, arterial supply, and venous drainage of the insula and sylvian fissure. The neural, arterial, and venous anatomy of the insula and sylvian fissure were examined in 43 cerebral hemispheres. The majority of gyri and sulci of the frontoparietal and temporal opercula had a constant relationship to the insular gyri and sulci and provided landmarks for approaching different parts of the insula. The most lateral lenticulostriate artery, an important landmark in insular surgery, arose 14.6 mm from the apex of the insula and penetrated the anterior perforated substance 15.3 mm medial to the limen insulae. The superior trunk of the middle cerebral artery (MCA) and its branches supplied the anterior, middle, and posterior short gyri; the anterior limiting sulcus; the short sulci; and the insular apex. The inferior trunk supplied the posterior long gyrus, inferior limiting sulcus, and limen area in most hemispheres. Both of these trunks frequently contributed to the supply of the central insular sulcus and the anterior long gyrus. The areas of insular supply of the superior and inferior trunks did not overlap. The most constant insular area of supply by the cortical MCA branches was from the prefrontal and precentral arteries that supplied the anterior and middle short gyri, respectively. The largest insular perforating arteries usually arose from the central and angular arteries and most commonly entered the posterior half of the central insular sulcus and posterior long gyrus. Insular veins drained predominantly to the deep middle cerebral vein, although frequent connections to the superficial venous system were found. Of all the insular veins, the precentral insular vein was the one that most commonly connected to the superficial sylvian vein.

An aberrant axillary artery penetrating the origin of the radial nerve from deep to superficial

An aberrant axillary artery that penetrated the radial nerve from deep to superficial during its course, was observed. The brachial plexus in the present case was classified as the Adachi's C-type brachial plexus. Further, an accessory radial root existed, which was a nerve bundle branching from the deep aspect of the inferior trunk and communicating with the radial root from the posterior cord to form the radial nerve. The axillary artery went on along the lower border of the brachial plexus and passed between the radial root and the accessory radial root from deep to superficial at its third section. As the axillary artery penetrated the origin of the radial nerve from deep to superficial, it was judged to reach deep under the posterior cord, hence deeper than the brachial plexus.

中大脳動脈りゅう（Ｍ１‐２分岐部）への最適接近法の選択

The surgical treatment of the middle cerebral artery (M1-2 bifurcation) aneurysm (MCA AN) employs the pterional approach and comprises much of aneurysm surgeries. But the surgical management of MCA AN remains a technically challenging problem especially for inexperienced neurosurgeons. This is largely caused by the difficulty of securing the M1 artery as the parent artery before exposing the whole aneurysm. In this study, we retrospectively analyzed the relationship between the approaches and operative difficulties in 90 MCA ANs in 86 of our patients operated on by the same neurosurgeon (K.U.). The variations of the MCA ANs were classified according to the following 3 points: the length of M1, M1 configuration on the angiogram (antero-posterior view), and the aneurysmal dome direction to M2. We subdivided the pterional approach into the following 4 groups: 1) the proximal approach (PA) to secure the proximal M1 after having controlled the internal carotid artery, 2) the distal approach (DA) to secure the distal M1 in the space between M2 arteries after having opened the distal sylvian fissure, 3) the superior approach (SA) to secure the distal M1 after having opened the distal sylvian fissure and followed the medial surface of M2 superior trunk, and 4) the inferior approach (IA) to secure the distal M1 after having opened the distal sylvian fissure and followed the lateral surface of M2 inferior trunk. The PA is effective in the cases of short M1 but in the cases of long M1 the DA is effective. The PA is safe for the cases in which the direction of the aneurysm is at the medial side of M2 arteries. On the other hand, in the cases in which the direction of the aneurysm is lateral to the M2 arteries, DA and SA are safe. In view of the results, we designed a scoring system to indicate the difficulties of securing M1 as the parent artery regarding the above-mentioned 3 points. Using these scores, we were able to decide the optimum approach preoperatively. To secure the parent artery is indispensable to safe aneurysm surgery. Comparing the points of each approach to the aneurysm with this scoring system, we were able to construct a better and safer micro-dissection plan with the goal of securing the parent M1 artery, and perform the operation by following the pre-operative plan. Surgical success or failure is determined by preoperative planning.

Relieving effects of electroacupuncture on mechanical allodynia in neuropathic pain model of inferior caudal trunk injury in rat: mediation by spinal opioid receptors

The relieving effects of electroacupuncture (EA) on mechanical allodynia and its mechanism related to the spinal opioid system were investigated in a rat model of neuropathic pain. To produce neuropathic pain in the tail, the right superior caudal trunk was resected between the S1 and S2 spinal nerves. Two weeks after the surgery, EA stimulation (2 or 100 Hz, 0.3 ms, 0.2–0.3 mA) was delivered to Zusanli (ST36) for 30 min. The degree of mechanical allodynia was evaluated quantitatively by touching the tail with von Frey hair (2.0 g) at 10 min intervals. These rats were then subjected to an i.t. injection with one of the three specific opioid agonists in successive ways: the mu agonist (DAMGO 25, 50 and 100 pmol), the delta agonist (DADELT II 0.5, 1 and 2 nmol), and the kappa agonist (U50488H 5, 10 and 20 nmol) separated by 10 min in cumulative doses. During 30 min of EA stimulation, specific opioid antagonists were subjected to i.t. injection: the mu antagonist (β-FNA 5, 10 and 20 nmol), the delta antagonist (naltrindole 5, 10 and 20 nmol), and the kappa antagonist (nor-BNI 3, 6 and 12 nmol) separated by 10 min in cumulative doses. As a result, EA reduced the behavioral signs of mechanical allodynia. Two Hz EA induced a robust and longer lasting effect than 100 Hz. All three opioid agonists also showed relieving effects on mechanical allodynia. However, nor-BNI could not block the EA effects on mechanical allodynia, whereas β-FNA or naltrindole significantly blocked EA effects. These results suggest that the mu and delta, but not kappa, opioid receptors in the spinal cord of the rat, play important roles in mediating relieving effects on mechanical allodynia induced by 2 Hz EA.

Brachial plexus variations in human fetuses.

We examined the anatomic variations of the brachial plexus (BP) in human fetuses. This study was performed with 200 BPs from spontaneously aborted fetuses without detectable malformations. The plexuses were dissected, and the normal position and/or morphological variations of the BP were determined and photographed. There were no variations in 93 plexuses, and 107 plexuses were observed to have different variations. Morphological variations were observed more frequently among female fetuses and right sides. The BPs were composed mostly of the C5, C6, C7, and C8 nerves and the T1 nerve (71.5%). A prefixed plexus was observed in 25.5% of cases, and a postfixed plexus was observed in 2.5% of cases. In one case (0.5%), the C4 and T2 nerves joined the formation. The inferior trunk was not formed in 9% of cases. The superior trunk was not formed in 1% of cases. In one plexus, the superior trunk was formed by the ventral rami of the C4 and C5 nerves. In one case, the inferior trunk was formed by the ventral rami of the T1 and T2 nerves. Division variations were observed most frequently. There were also variations in the terminal branches, such as the roots of the median nerve joining in the distal part of the arm (8.5%), the axillary nerve being separate from the posterior division of the superior trunk (2.5%), and a connection existing between the median and musculocutaneous nerves (1%). Knowledge of BP variations is important for surgeons who perform surgical procedures in the cervical and axillary regions.

Increases in spinal vasoactive intestinal polypeptide and neuropeptide Y are not sufficient for the genesis of neuropathic pain in rats

We tested the hypothesis that increases in the spinal levels of vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) were related to the development of neuropathic pain. To this aim, we compared two groups of rats. One group showed well-developed neuropathic pain in the tail following unilateral transection of the inferior and superior caudal trunks between the S1 and S2 spinal nerves, and the other group showed poorly-developed neuropathic pain despite the same nerve injury. The increases in immunoreactivity of VIP and NPY in the S1 dorsal horn (injured segment) were not significantly different between the two groups. These results suggested that increases in the spinal levels of VIP and NPY after peripheral nerve injury were not sufficient for the development of neuropathic pain.

中大脳動脈分岐部動脈りゅうに対する手術アプローチの考察 ３Ｄ‐ＤＳＡおよび術中所見の観察から

Recent advances in neuroimaging, including 3-dimensional digital subtraction angiography (3D-DSA), enable the detailed delineation of structural characteristics of aneurysm and the parent artery. We retrospectively reviewed the operative findings and 3D-DSA images of middle cerebral artery bifurcation aneurysm (MCB-An). Morphology of MCB and An, approach to the An, and the operative view in the clipping procedure were considered in 31 MCB-Ans in 29 consecutive cases operated in 2001. In most cases, we used the distal approach, splitting the sylvian fissure from the lateral to medial direction, for clipping the MCB-An. Proximal control of the M1 was achieved in all cases. The proximal approach was performed in a case presenting with the ipsilateral internal carotid artery An. There were 2 patterns of approach angle. One is the medial trans-sylvian (m-TS) approach, in which clipping was attempted after the M1 was ensured beyond the frontal operculum. It was used in 18 cases. The other approach is the lateral trans-sylvian (l-TS) approach, which was used in 13 cases. Proximal control of the M1 was achieved between the superior and inferior trunks. The l-TS approach required an angle of approach more from the lateral and rostral side than the m-TS approach. The l-TS approach was used in cases presenting with the distal M1 running more anteroinferiorly, as compared with the m-TS approach. Morphology of the parent artery, and the relation of An and those vessels were clearly evaluated in 3D-DSA. Preoperative evaluation of 3D structures enables safe aneurysm surgery with minimum surgical procedure.

Coexistence of multiple anomalies in the celiac-mesenteric arterial system.

The origins and distribution of arteries of the celiac-mesenteric system were examined by dissection of 52 formalin-fixed human cadavers. Seventy-five percent of the cadavers exhibited the classic Michels' Type I hepatolienogastric pattern; 25% had different branching patterns. Multiple anomalies of the celiac-mesenteric arterial system were observed in one Caucasian female cadaver: a short lienogastric trunk; a common hepatic artery arising directly from the abdominal aorta; an anomalous course of the hepatic arteries; an accessory left hepatic artery arising from the left and right gastric arterial anastomosis along the lesser curvature of the stomach; a double cystic artery; a common inferior phrenic trunk arising from the celiac trunk; and an aberrant arterial channel connecting the proximal segments of the splenic and gastroduodenal arteries. A patent ductus venosus and an anomalous formation of the portal vein by the confluence of the splenic and superior and inferior mesenteric veins was also observed. Although single anomalies of the celiac-mesenteric arterial system are common, complex combinations, such as were observed in the present case, represent a significant deviation from the normal developmental pattern. There seems to be no report in the literature of such a combination of anomalies coexisting in one individual. The developmental and clinical significance of these anomalous vessels is discussed.

Configurations of the segmental and subsegmental bronchi and arteries in the right upper lobe of the human lung with special reference to their concomitant relations and double subsegmental arterial supply.

The basic, concomitant topographical relation between the segmental bronchus and artery shows derived figures in the dorsolateral part of the cranial portion of the mammalian lung, especially in humans. However, the pulmonary arterial supply has not been investigated well in the subsegmental level, even in humans. One or two subsegments of S2 received a double arterial supply from both the superior and inferior pulmonary trunks in 39.8% of the right upper lobes of 194 human lung dissections, whereas 20.6% did so in S3, although the latter cases were limited to one of the two subsegments. Moreover, we found several arterial patterns that were significantly frequently observed in a specific group of the bronchial tree in S2 and/or S3. Invasion of an additional artery of inferior trunk origin seemed to happen at the same time in both segments even without complementary territorial relations with the essential segmental artery of the superior trunk origin. S2 and S3 in the human right lung seemed to be the best fields for reconsideration of the basic rules in the lung segment system in mammals as a result of their having the largest sets of variations. We speculate that the discrepancy between the bronchial and arterial ramification patterns, which was frequently found in S2 and S3, is a result of a hypothetical secondary increase of the comparative volume of this area in evolution and/or development of the lung.

Reconstruction par lambeaux libres dans les sarcomes localement évolués

Study aim: The aim of this retrospective study was to assess the advantages of free-lap reconstruction in locally advanced soft tissue sarcomas. Patients and method: From October 1997 to October 2000, among 256 procedures for sarcomas, 25 were associated with free-lap reconstruction. There were 16 women and nine men (mean age: 45 years). The tumor was located on inferior limbs ( n= 15), superior limbs ( n = 3) and trunk ( n = 7), had a mean size of 12, 10 and 12 cm respectively, and was multifocal ( n = 6), or recurrent ( n = 10). Ten patients received a neoadjuvant chemotherapy. Tumoral excision was associated with a complementary procedure in 10 patients. Reconstruction was performed with free-laps of the latissimus dorsi ( n = 21) and transverse rectus abdominis myocutaneous (TRAM) ( n = 4). Early postoperative radiotherapy was associated in 15 patients. Results: Median duration of the procedure was 6.5 hours. There were no postoperative deaths. Two free-laps necrotized and another free-lap was constructed. Tumoral excision was R 0 ( n = 20), R 1 ( n = 4) and R 2 ( n = 1). With a median follow-up of 20 months, there were no local recurrences in patients R 0. Ten patients developed pulmonary metastases and five of them died. Conclusion: With free-lap reconstruction, tumoral excision was larger, amputation of the limb was avoided in 14 patients, and early postoperative radiotherapy was possible in 15 patients. Multidisciplinary management and collaboration of the oncologist and plastic surgeon are associated with a better prognosis of locally advanced soft tissue sarcomas.

Decrease in spinal CGRP and substance P is not related to neuropathic pain in a rat model.

We tested the hypothesis that the decrease in spinal levels of SP and CGRP after peripheral nerve injury is related to neuropathic pain. We compared two groups of rats, both of which were subjected to unilateral transection of the inferior and superior caudal trunks between the S1 and S2 spinal nerves. One group exhibited well-developed neuropathic signs after the nerve injury, whereas the other group showed poorly developed signs despite the same nerve injury. The decrease in immunoreactivity of CGRP and SP in the S1 dorsal horn (injured segment) was not significantly different between the two groups. These results suggest that the decrease in spinal levels of CGRP and SP after peripheral nerve injury is not related to neuropathic pain.

Peripheral nerve injuries during cardiac surgery: risk factors, diagnosis, prognosis, and prevention.

Neuropathies involving the brachial plexus, phrenic, recurrent laryngeal, and saphenous nerves, as well as the sympathetic chain are complications of cardiac surgery. The reported frequency of nerve injuries varies from 1.5% to 24% for the brachial plexus and 10% to 60",,6 for the phrenic nerve (1-5). Neuropathies of the recurrent laryngeal, lower limb (saphenous) nerves, and the sympathetic chain are less frequent.

Association of kappa opioid receptor mRNA upregulation in dorsal root ganglia with mechanical allodynia in mice following nerve injury

This study examined the contribution of nerve injury alone or nerve injury with signs of neuropathic pain to alteration of kappa opioid receptor (KOR) mRNA expression. Two groups of mice, both of them were subjected to unilateral transection of the inferior and superior caudal trunks at the S1 spinal nerve, were compared with respect to KOR mRNA expression by reverse transcriptase-polymerase chain reaction. One group showed exclusive pain behavior (PB+) as mechanical allodynia, and the other group exhibited no enhanced sensitivity to innocuous mechanical stimulation to the tail (PB−). Expression of total KOR and variants B and C mRNA increased ipsilaterally in dorsal root ganglia (DRG) of PB+ mice, whereas KOR variant A mRNA was not detected in DRG. These results show that KOR mRNA expression differs between PB+ and PB− groups of mice after nerve injury, and suggest an association of KOR expression with mechanical allodynia.

The anatomy of the pectoral nerves and their significance in brachial plexus reconstruction.

Twenty-nine brachial plexuses from 13 embalmed and 5 fresh cadavers were examined under x3.5 loupe magnification to collect systematic and topographic anatomical data regarding the lateral and medial pectoral nerves. Additionally, nerve biopsy specimens were harvested in 5 fresh cadavers to obtain histomorphometric data. In all dissections the pectoral nerves exited at the trunk level as 3 distinct nerves. The superior pectoral nerve (from the anterior division of the superior trunk) commences just distal to the suprascapular nerve and courses laterally to innervate the lateral clavicular portion of the pectoralis major muscle (PM) with 2 to 4 branches. The middle pectoral nerve (from the anterior division of the middle trunk) courses distally and enters the infraclavicular fossa with 2 constant branches. The superficial branch terminates in the medial clavicular and upper sternal parts of the PM. The deep branch always forms a plexus with the medial pectoral or inferior pectoral nerve (from the anterior division of the inferior trunk), which courses at a right angle around the the lateral thoracic artery. From this plexus several branches terminate in the Pm. The branch to the lower aspect of the PM pierces the pectoralis minor muscle in two thirds of cases, whereas it passes its inferior border to reach the lower aspects of the PM with an average length of 15 cm in one third of cases. Knowledge of the detailed anatomy of the pectoral nerves, as outlined in this study, clarifies the obscure anatomic relationship of the lateral and medial pectoral nerves and allows easy intraoperative location of the medial pectoral nerve at the exit of the lateral thoracic artery. The length of the inferior pectoral nerve, the number of motor axons, and the anatomical proximity of this nerve make it an expendable but powerful source of reinnervation to the musculocutaneous nerve in upper brachial plexus injuries.

Role of signals from the dorsal root ganglion in neuropathic pain in a rat model

We examined whether signals from the neuroma or the dorsal root ganglion of the injured segment are critical for the generation of neuropathic pain. To this aim, we used a rat model of peripheral neuropathy made by transecting the inferior and superior caudal trunks at the level between the S1 and S2 spinal nerves under enflurane anesthesia. These animals displayed tail-withdrawal responses to normally innocuous mechanical stimulation applied to the tail with a von Frey hair (2 g). Also, these animals, compared to pre-surgical value, displayed shorter tail-withdrawal latencies following immersion of the tail to warm (40°C) or cold (4°C) water. Transection of the S1 spinal nerve between the dorsal root ganglion and neuroma did not change the behavioral signs of neuropathic pain. In contrast, S1 dorsal rhizotomy significantly reduced the behavioral signs. The data suggest that signals arising from the dorsal root ganglion cells of the injured segment, but not from the neuroma, are critical for the generation of neuropathic pain in this model.

Is sympathetic sprouting in the dorsal root ganglia responsible for the production of neuropathic pain in a rat model?

Partial peripheral nerve injury often results in neuropathic pain that is aggravated by sympathetic excitation and induces sympathetic nerve sprouting in both the injured nerve and corresponding dorsal root ganglia (DRGs). Presently, the functional mechanisms of the interactions between the sprouting and injured somatic afferents remain uncertain. This study was performed to see whether the sprouting in the DRGs plays a key role in the development of neuropathic pain. To this aim, we compared two groups of rats, both of which were subjected to unilateral transection of the superior and inferior caudal trunks at the level between the S1 and S2 spinal nerves, with respect to sympathetic fiber sprouting; one group showed well-developed neuropathic pain behaviors (i.e. mechanical, cold and warm allodynia signs) and the other group showed poorly-developed ones. Immuno-histochemical staining with tyrosine hydroxylase (TH) antibody of the injured S1 DRG taken from both groups of rats after behavioral tests revealed that the magnitude of penetration of TH-positive fibers into the S1 DRG was not significantly different between the two groups. These results suggest that sympathetic nerve sprouting in the injured DRG is not a key factor in the development of neuropathic pain.