Long-term outcomes of carotid artery stenting in patients with carotid artery stenosis: A single-center 14-year retrospective analysis

Objective@#Carotid artery stenting (CAS) is currently widely used for the treatment of carotid artery stenosis. The objective of this study was to analyze the outcomes of CAS performed in a single institution. @*Methods@#We retrospectively analyzed 313 CAS cases from January 2007 to December 2020, including 206 (66%) symptomatic and 107 (34%) asymptomatic cases. Procedure-related morbidity and mortality were assessed. Rates of periprocedural (≤30 days after CAS) and postprocedural ipsilateral strokes (>30 days after CAS) were also assessed. Logistic regression analysis was used to identify risk factors for the periprocedural complication, in-stent restenosis (ISR), and ipsilateral stroke. @*Results@#The success rate of CAS was 98%. Among 313 cases, 1 patient died due to hyperperfusion-related intracerebral hemorrhage (ICH). The CAS-related mortality rate was 0.31%. The overall incidence of periprocedural complications is 5.1%. A risk factor for periprocedural complication was a symptomatic carotid artery stenosis (7.3% vs. 0.9%, p=0.016). Twenty cases of ISR occurred during 63.7±42.1 months of follow-up. The overall incidence of ISR was 10.2% (20/196). A risk factors for ISR were diabetes mellitus (17.6% vs. 5.7%, p=0.008) and patients who used Open-cell stents (19.6% vs. 6.9%, p=0.010). The overall incidence of ipsilateral stroke is 5.6%. A risk factors for ipsilateral stroke was ISR (95% CI, p=0.002). @*Conclusions@#CAS is a safe and effective procedure for carotid artery stenosis. Although the incidence of complications is low, fatal complication such as hyperperfusion- related ICH can occur. To prevent hyperperfusion-related ICH, several methods such as strict blood pressure (BP) control, intentional less widening of stenotic segment should be used. To prevent ISR or stroke occurrence, special attention should be paid to patients who have ISR or ipsilateral stroke risk factors.

Multiple Cerebral Hemorrhages Caused by Paradoxical Reperfusion Injury After Cranioplasty / 대한신경손상학회지

Cranioplasty-related reperfusion injury has rarely been reported. Although there are several hypotheses, particularly regarding the mechanisms of the event, clear evidence is lacking. Here, we report the case of an 84-year-old man with traumatic intracranial hemorrhage and subdural hematoma who underwent decompressive craniectomy and hematoma evacuation in the right hemisphere. After 45 days, cranioplasty was performed using titanium. A preoperative perfusion study with 99m-Tc-HMPAO brain single-photon emission tomography revealed diffuse hypoperfusion in the left cerebral hemisphere with decreased vascular reserve. After cranioplasty, multiple cerebral hemorrhages were observed on immediate postoperative computed tomography. Cerebral hemorrhage eventually improved without surgery. Here, we report a case with findings revealed through perfusion studies before and after surgery.

Short and Long-term Outcomes of Subarachnoid Hemorrhage Treatment according to Hospital Volume in Korea: a Nationwide Multicenter Registry

Background@#Subarachnoid hemorrhage is a potentially devastating cerebrovascular attack with a high proportion of poor outcomes and mortality. Recent studies have reported decreased mortality with the improvement in devices and techniques for treating ruptured aneurysms and neurocritical care. This study investigated the relationship between hospital volume and shortand long-term mortality in patients treated with subarachnoid hemorrhage. @*Methods@#We selected subarachnoid hemorrhage patients treated with clipping and coiling from March–May 2013 to June–August 2014 using data from Acute Stroke Registry, and the selected subarachnoid hemorrhage (SAH) patients were tracked in connection with data of Health Insurance Review and Assessment Service to evaluate the short-term and long-term mortality. @*Results@#A total of 625 subarachnoid hemorrhage patients were admitted to high-volume hospitals (n = 355, 57%) and low-volume hospitals (n = 270, 43%) for six months. The mortality of SAH patients treated with clipping and coiling was 12.3%, 20.2%, 21.4%, and 24.3% at 14 days, three months, one year, and five years, respectively. The short-term and long-term mortality in high-volume hospitals was significantly lower than that in low-volume hospitals. On Cox regression analysis of death in patients with severe clinical status, lowvolume hospitals had significantly higher mortality than high-volume hospitals during shortterm follow-up. On Cox regression analysis in the mild clinical status group, there was no statistical difference between high-volume hospitals and low-volume hospitals. @*Conclusion@#In subarachnoid hemorrhage patients treated with clipping and coiling, lowvolume hospitals had higher short-term mortality than high-volume hospitals. These results from a nationwide database imply that acute SAH should be treated by a skilled neurosurgeon with adequate facilities in a high-volume hospital.

Short and Long-term Outcomes of Subarachnoid Hemorrhage Treatment according to Hospital Volume in Korea: a Nationwide Multicenter Registry

Background@#Subarachnoid hemorrhage is a potentially devastating cerebrovascular attack with a high proportion of poor outcomes and mortality. Recent studies have reported decreased mortality with the improvement in devices and techniques for treating ruptured aneurysms and neurocritical care. This study investigated the relationship between hospital volume and shortand long-term mortality in patients treated with subarachnoid hemorrhage. @*Methods@#We selected subarachnoid hemorrhage patients treated with clipping and coiling from March–May 2013 to June–August 2014 using data from Acute Stroke Registry, and the selected subarachnoid hemorrhage (SAH) patients were tracked in connection with data of Health Insurance Review and Assessment Service to evaluate the short-term and long-term mortality. @*Results@#A total of 625 subarachnoid hemorrhage patients were admitted to high-volume hospitals (n = 355, 57%) and low-volume hospitals (n = 270, 43%) for six months. The mortality of SAH patients treated with clipping and coiling was 12.3%, 20.2%, 21.4%, and 24.3% at 14 days, three months, one year, and five years, respectively. The short-term and long-term mortality in high-volume hospitals was significantly lower than that in low-volume hospitals. On Cox regression analysis of death in patients with severe clinical status, lowvolume hospitals had significantly higher mortality than high-volume hospitals during shortterm follow-up. On Cox regression analysis in the mild clinical status group, there was no statistical difference between high-volume hospitals and low-volume hospitals. @*Conclusion@#In subarachnoid hemorrhage patients treated with clipping and coiling, lowvolume hospitals had higher short-term mortality than high-volume hospitals. These results from a nationwide database imply that acute SAH should be treated by a skilled neurosurgeon with adequate facilities in a high-volume hospital.

Gelfoam Embolization Technique to Prevent Bone Cement Leakage during Percutaneous Vertebroplasty: Comparative Study of Gelfoam only vs. Gelfoam with Venography / 대한신경손상학회지

Objective@#Percutaneous vertebroplasty (VP) has been used for the safe treatment of osteoporotic compression fracture. However, cement leakage is the most common complication. To reduce the leakage of bone cement, we did the gelfoam embolization during VP. The purpose of this study is to compare the safety and feasibility of different two gelfoam embolization technique during VP. @*Methods@#Total 127 patients (146 level) who had the thoracolumbar osteoporotic compression fracture were enrolled. Group A was treated by gelfoam-only technique and, Group B was treated by gelfoam with venography technique. We compared the incidence of bone cement leakage between two groups using post-operative computed tomography scan and X-ray. @*Results@#Seventy-four patients (81 levels) were treated with gelfoam-only technique (A), and 53 patients (65 levels) were treated with gelfoam with venography technique (B). There were 22 leakages on group A, and 19 leakages on group B. There was no statistical significant difference between two groups (Chi-square test, p-value =0.958). Incidence of leakage to spinal canal was 11 levels in Group A, 3 levels in group B, and there was statistical significant difference (Fisher's exact test, p-value=0.027). @*Conclusion@#Complication induced by the bone cement leakage are the most careful point during VP. Gelfoam embolization with venography is very easy and safe method. Gelfoam with venography technique could make lower the incidence of cement leakage to spinal canal.

Surgical Outcome of Posterior Pelvic Fixation Using S1, S2 Screws in Vertically Unstable Pelvic Ring Injury

PURPOSE: Iliosacral screw fixation is an effective and less invasive method that is used widely for the definitive treatment of unstable pelvic ring injuries. On the other hand, fixation failures after iliosacral screw fixation have been reported in vertically unstable pelvic ring injuries. This study examined the surgical outcomes of posterior pelvic fixation using S1 and S2 screws in vertically unstable pelvic ring injuries. MATERIALS AND METHODS: Between January 2011 and April 2016, 17 patients with vertically unstable pelvic ring injuries who met the minimum 1 year follow-up criteria were treated with internal fixation using posterior pelvic S1 and S2 screws. Their mean age was 43.9 years. According to the AO/OTA classification, 10 patients had C1, 6 had C2, and 1 had C3 injuries. Surgical treatments of single or multiple steps, where necessary, were performed by two surgeons. The clinical and radiologic outcomes were assessed retrospectively using radiographs and medical records. RESULTS: Overall, 16 patients had bone healing without screw loosening; however, one patient could not maintain anterior pelvic fixation because of an open fracture and deep infection in the anterior pelvic ring. Of five patients who complained of neurological symptoms after injury, three had partially recovered from their neurological deficit. At the last follow-up, the clinical outcomes according to the Majeed score were excellent in 5, good in 6, fair in 4, and poor in 2 patients. The postoperative radiologic outcomes by Matta and Tornetta's method were excellent in 5, good in 8, and fair in 4 patients. Malposition of the S2 screw was identified in one case. The mean time to union was 14.6 weeks after surgery. CONCLUSION: S1 and S2 screw fixation can be an effective treatment option for posterior pelvic stabilization in vertically unstable pelvic ring injuries when considering the surgical outcomes, such as screw loosening and loss of reduction.

Surgical Outcomes of Biologic Fixation for Subtrochanteric Fracture Using Locking Compression Plates / 대한고관절학회지

PURPOSE: This study aimed to evaluate the surgical outcomes of biologic plating using locking compression plate-distal femur (LCP-DF) in patients with subtrochanteric fracture of the femur. MATERIALS AND METHODS: Between January 2010 and December 2013, 28 consecutive patients with subtrochanteric fractures of the femur, treated with biologic fixation using LCP-DF, were enrolled. Preoperative values, including patient age, sex, body mass index, fracture type, type of lung injury, and surgical timing from injury to surgery, were retrospectively evaluated. Radiologic assessments included time to union, coronal alignment, rotational alignment, and complications such as implant breakage and screw breakage. Adverse events, including postoperative fat embolism and adult respiratory distress syndrome, infection during the follow-up period, and walking ability at the last follow-up visit, were assessed. RESULTS: Union was achieved in 27 patients (96.4%) after a mean duration of 5.4 months (range, 3-14 months). No patients developed fat embolism or adult respiratory distress syndrome during the hospitalization period of this study. CONCLUSION: Biologic fixation using locking compression plates may represent a safe surgical option which can be utilized in patients with subtrochanteric fracture regardless of injury severity, surgical timing, fracture type, and presence of lung injury.

Clinical Features of Interhemispheric Subdural Hematomas / 대한신경손상학회지

OBJECTIVE: Interhemispheric subdural hematoma (IHSDH) is uncommon, because of their unusual location. However, it is a distinct lesion with its unique characteristics. We investigated clinical features and outcomes of consecutive 42 patients with IHSDH, retrospectively. METHODS: From 2006 to 2015, we treated 105 patients with IHSDH. All patients were diagnosed by computed tomography (CT) or magnetic resonance imaging. We selected 42 patients with thick (3 mm or more) IHSDH. We retrospectively reviewed the clinical and radiological findings, management and outcomes. RESULTS: The male to female ratio was 2:1. Two thirds of the patients were over 60 years old. Slip or fall was the most common cause of trauma. The level of consciousness on admission was Glasgow Coma Scale (GCS) 13 to 15 in 25 patients. The most common symptom was headache. All IHSDH was hyperdense in CT at the time of diagnosis. IHSDH frequently accompanied convexity subdural hematoma. The outcome was favorable in 27 patients, however, six patients were expired. Twenty-two patients were managed conservatively. Surgery was performed in ten patients to remove the concurrent lesion. The outcome was poor in spontaneous one, patients with low GCS, and patients with conservative treatment. CONCLUSION: IHSDH is rare especially the isolated one. The outcome was dependent to the severity of injury. Surgery may be helpful to remove the concurrent mass lesion, however, conservative treatment is generally preferred.

Procedure-related Complications during Endovascular Treatment of Intracranial Saccular Aneurysms

OBJECTIVE: We evaluate the rates and outcomes of major procedure-related complications during coiling. MATERIALS AND METHODS: Between 2007 and 2015, 436 intracranial saccular aneurysms were treated. Complications are categorized as three types: intraprocedural aneurysm rupture (IAR), thromboembolism (TE), and post-procedural early rebleeding (PER). And we evaluated the risk factors of procedure related complications by multivariate analysis. RESULTS: Complications occurred in 61 aneurysms (14%). The overall incidence of complications in subarachnoid hemorrhage (SAH) was significantly higher than in unruptured intracranial aneurysm (UIA) (20% vs. 6%). The incidence of IAR and TE were higher in SAH than in UIA (IAR 12% vs. 4%, TE 7% vs. 3%, p 0.05). All 7 patients who had IAR during BAC had good recovery. In multiple logistic regression analysis, female gender, SAH, and intraventricular hemorrhage were associated with procedure related complication (p < 0.05). CONCLUSION: Endovascular coil embolization is a minimally invasive procedure, but incidence of its complication is not low, especially in SAH. BAC can be a good tool to avoid poor outcome from unexpected IAR during coiling. While IA tirofiban injection is a useful therapy in TE during coiling, sometimes we are aware of the risk of the early rebleeding in SAH patients.

Anatomy, Classification and Radiology of the Pelvic Fracture

No abstract available.

Septic Hip Arthritis with Iliopsoas Abscess Detected after Spine Operation: A Case Report / 대한고관절학회지

In the elderly patients who complain of pain in the buttock and leg, it is not easy to distinguish whether the pain comes from the lesion of the hip or from the spine. A 78-year-old female who was treated conservatively for persistent pain in the right buttock and leg after an operation for spinal stenosis in the local clinic visited our clinic. Septic hip arthritis with severe femoral head destruction and multiple abscesses in the buttock and iliopsoas muscle were diagnosed 2 months postoperatively, and spinal abscess in the site of the previous operation was detected by a subsequent MRI study. To avoid such a delay of the diagnosis and treatment, it is important to suspect hip joint lesion earlier for the source of persistent pain after a spine operation. Further more, diagnostic evaluation is necessary to rule out co-infection of the spine or iliopsoas muscle when a hip joint infection exists.

Early Results of One-Stage Correction for Hip Instability in Cerebral Palsy

BACKGROUND: We evaluated the clinical and radiological results of one-stage correction for cerebral palsy patients. METHODS: We reviewed clinical outcomes and radiologic indices of 32 dysplastic hips in 23 children with cerebral palsy (13 males, 10 females; mean age, 8.6 years). Ten hips had dislocation, while 22 had subluxation. Preoperative Gross Motor Function Classification System (GMFCS) scores of the patients were as follows; level V (13 patients), level IV (9), and level III (1). Acetabular deficiency was anterior in 5 hips, superolateral in 7, posterior in 11 and mixed in 9, according to 3 dimensional computed tomography. The combined surgery included open reduction of the femoral head, release of contracted muscles, femoral shortening varus derotation osteotomy and the modified Dega osteotomy. Hip range of motion, GMFCS level, acetabular index, center-edge angle and migration percentage were measured before and after surgery. The mean follow-up period was 28.1 months. RESULTS: Hip abduction (median, 40degrees), sitting comfort and GMFCS level were improved after surgery, and pain was decreased. There were two cases of femoral head avascular necrosis, but no infection, nonunion, resubluxation or redislocation. All radiologic indices showed improvement after surgery. CONCLUSIONS: A single event multilevel surgery including soft tissue, pelvic and femoral side correction is effective in treating spastic dislocation of the hip in cerebral palsy.

Arthroscopically Assisted Reduction and Internal Fixation of Intra-Articular Fractures of Tibial Plateau / 대한정형외과학회잡지

PURPOSE: To evaluate clinical and radiological results of arthroscopically assisted reduction and internal fixation of intra-articular fractures of the tibial plateau. MATERIALS AND METHODS: Between July 2003 and June 2009, we performed arthroscopy and fluoroscopy-assisted reduction and internal fixation for tibia plateau fracture. Our study included 21 patients who had been followed-up for more than 18 months. We used the Knee Society Knee Score (KSS) and Knee Society Functional Score (KSFS) for the clinical evaluation. We used the Rasmussen Radiological Score for the radiological evaluation. RESULTS: At the last follow-up, all 21 cases showed bone union, and the mean range of movement was 115.5+/-8.5degrees. According to the KSS and KSFS, we obtained excellent or good results in 18 cases (85%). We obtained excellent or good results in 19 cases (90%) each by the Rasmussen Clinical Score and Rasmussen Radiological Score, respectively. CONCLUSION: The 2 year follow-up of arthroscopy assisted surgery showed relatively satisfactory results.

Reconstruction of Acetabular Posterior Wall Fractures

BACKGROUND: The results after acetabular fracture are primarily related to the quality of the articular reduction. We evaluated the results of internal fixation of posterior wall fractures with using three-step reconstruction. METHODS: Thirty-three patients (mean age at the time of injury, 47.9 years; 28 males and 5 females) were followed for a minimum of 2 years after surgery. The three-step reconstruction included 1) preservation of soft tissues and reduction of the marginally impacted osteochondral (articular) fragments using screws, 2) filling the impacted cancellous void with a bone graft, and 3) reinforcement with buttress-plating. Clinical evaluation was done according to the criteria of D'aubigne and Postel, while the radiological criteria were those of Matta. The associated injuries and complications were evaluated. RESULTS: The clinical results were excellent in 15 (45.5%) patients and they were good in 5 (15.2%), (i.e., satisfactory in 60.7%), while the radiologic results were excellent in 10 (30.3%) and good in 14 (42.4%) (satisfactory in 72.7%). Heterotopic ossification was common, but this did not require excision, even without prophylactic treatment with indomethacin. Deep infection was the worst complication and this was accompanied by a poor outcome. CONCLUSIONS: This study confirms that three-step reconstruction facilitates accurate and firm reduction of displaced posterior wall fractures of the acetabulum. Therefore, we anticipate less long-term arthrosis in the patients treated this way.

Comparison of the Compression Hip Screw (CHS) and the Proximal Femoral Nail Antirotation (PFNA) for Intertrochanteric Femoral Fracture

PURPOSE: To evaluate the radiologic, clinical results between who had intertrochanteric fracture, treated with Compression Hip Screw (CHS) and Proximal Femoral Nail Antirotation (PFNA). MATERIALS AND METHODS: We retrospectively reviewed each 36 and 48 patients of intertrochanteric fracture which were treated with CHS or PFNA by one surgeon from January 2005 to June 2009. We evaluated mean operation time, amount of bleeding, radiologic results, and the clinical outcomes with the mobility score of Parker and Palmer, social function scoring system. RESULTS: The mean operation time, amount of bleeding were less in the PFNA group, there were 116.7 min, 486.1 ml for the CHS group versus 87.7 min, 289.6 ml for the PFNA group. The radiologic results were not significantly different. Decrease of mobility score of Parker and Palmer, social function score were similar. Proximal migration of leg screw and perforation of femoral head was 2 case and deep infection was 1 cases in CHS group. CONCLUSION: There were no significant differences that are clinical and radiological results in treatment of intertrochanteric fracture using the CHS and PFNA. But PFNA is less invasive device than CHS, therefore it may be useful device in elderly patients.

A Case of Multiple Rice Bodies by the Nonspecific Synovitis in the Knee Joint

Multiple rice bodies are commonly observed in various rheumatologic disorders and tuberculous arthritis, but rice bodies are rarely observed in nonspecific synovitis without any underlying disease. We performed arthroscopic rice body removal and synovectomy for nonspecific synovitis with multiple rice bodies in a 31-year-old male patient, and the results were satisfactory. No evidence of underlying disease, including rheumatoid arthritis or tuberculous arthritis, was observed during 2 years on the follow-up evaluations after the arthroscopic procedure. There have been very few confirmed rice bodies cases without underlying disease, so making a careful differential diagnosis to rule out rheumatologic and infectious disorders is required to avoid possible aggravation of disease, which may result in persistent articular cartilage destruction.

Bilateral Traumatic Locked Posterior Dislocation of the Shoulder: A Case Report

PURPOSE: Bilateral traumatic locked posterior dislocations of the shoulder are very rare and there has been no report on the operative treatment for this injury in the Korean medical literature. MATERIALS AND METHODS: We present here a case of bilateral locked posterior dislocations of the shoulders after trauma and this was successfully treated with open reduction and lesser tuberosity transfer on the right shoulder and subscapularis tendon transfer on the left shoulder. RESULTS AND CONCLUSION: Twenty-four months later, the clinical and radiologic results were excellent.

Early Results of TKA with Electromagnetic Navigation

PURPOSE: We compared the results of electromagnetic navigation assisted total knee arthroplasty (TKA) with that of conventional TKA from the viewpoint of the postoperative limb alignment and the implant position. MATERIALS AND METHODS: We retrospectively analyzed 115 consecutive total knee arthroplasties that were done between September 2006 and June 2007. There were 65 navigation assissted cases and 50 conventionally implanted cases. We analyzed the postoperative radiologic results, the clinical results over one year follow up after surgery and the range of motion (ROM). RESULTS: The postoperative mechanical axis deviation showed no significant difference between the two groups. However, the tibial zone, as assessed by Kennedy and White's method were at zone C for 60 cases (92%) in the navigation group and for 40 cases (80%) in the conventional group (p=0.01). On the coronal plane, the implant position of the femoral component was 89.4+/-4.1degrees in the navigation group and 87.6+/-4.3degrees in the conventional group (p<0.01), and the implant position of the tibial component was 89.7+/-1.1degrees and 91.9+/-1.8degrees in each group, respectively (p<0.01), and this shows the better result in the navigation group. CONCLUSION: Electromagnetic navigation assisted TKA had similar clinical results on the short-term follow up as compared with conventional TKA. However, it radiologically showed a more satisfactory position of the implant and it displayed superiority in locating the precise position of the femoral and tibial components, and especially on the coronal plane.

Two-Stage Reimplantation of Infected Total Knee Arthroplasty with Antibiotic-Loaded Bone Cement Spacer: Comparison of the Types of Antibiotic-Loaded Cement Spacer / 대한정형외과학회잡지

PURPOSE: The treatment results of a two-stage reimplantation of infected total knee arthroplasty with either the articulating or non-articulating types of antibiotic-loaded bone cement spacers were compared and analyzed. MATERIALS AND METHODS: Between July 1995 and October 2005, this study reviewed 29 patients who underwent two-stage reimplantation of infected total knee arthroplasty and were followed up for at least 2 years. Of the 29 cases, 12 used articulating and 17 used the non-articulating type. RESULTS: Fifteen cases (52%) showed bacterial growth in the preoperative and intraoperative bacterial culture, and 14 cases (48%) had no growth. 27 cases showed no evidence of reinfection until the last follow up after two-stage reimplantation. One out of the 12 cases in the articulating group and 1 out of the 17 cases in the non-articulating group had a reinfection. The range of motion (ROM) of the knee joint and HSS knee rating scale increased more significantly in the articulating group than in the non-articulating group, and the degree of increase in the ROM of the knee joint and HSS knee rating scale was significantly larger in the articulating group. CONCLUSION: The two-stage reimplantation with an antibiotic-loaded bone cement spacer showed a 93.1% of success rate. The articulating group showed better results in the knee ROM and HSS knee rating scale than the non-articulating group

Gene Expression Modulation in Rat Skeletal Muscle by Denervation-induced Atrophy / 대한정형외과연구학회지

PURPOSE: To understand the modulation of genes by atrophy, differential expression of genes in normal and denervated skeletal muscle was investigated by DNA chip technology. MATERIALS AND METHODS: Sciatic nerve and femoral nerve were resected in right leg of rat to make the muscle atrophy model. Muscle tissues from the gastrocnemius of normal and denervated legs were homogenized and RNA were extracted. Dyes were labelled during reverse transcription and hybridization was done into the DNA chip which is consisted of about 5,000 probes. RESULTS: By statistical analysis, 39 genes were selected as differentially expressed genes by atrophy. 15 known genes up-regulated by atrophy were genes related to immune response, extracellular matrix, andsignal transduction in plasma membrane. 7 known genes down-regulated by atrophy were genes related to cell growth and proliferation, intracellular signal transduction, and energy metabolism. Some unknown gene functions were analysed by bioinformatics analysis and they were highly homologous genes with McKusick-Kaufman syndrome protein, ADP-ribosylation factor-like 4, and component X of pyruvate dehydrogenase complex. CONCLUSION: These results suggest that reduction of energy metabolism, activation of cholesterol exclusion, and changes on signal transduction pathway are involved in the process of atrophy by denervation in skeletal muscle of rat.