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Wen-Jer Chen

Publications and source records attributed to Wen-Jer Chen.

At least 19 recordsLinked to original sources
PubMed2006

Percutaneous endoscopic discectomy and drainage for infectious spondylitis.

Fifteen patients with infectious spondylitis were treated by percutaneous endoscopic discectomy and drainage (PEDD) and associated appropriate parenteral antibiotics. Infectious spondylitis was diagnosed clinically, on the basis of elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values, and on roentgenographic and magnetic resonance imaging (MRI) findings. Causative bacteria were identified in 13 (86.7%) of 15 biopsy specimens. Systemic antibiotics were administered according to sensitivity analyses of pathogens. All patients reported immediate back pain relief except for two, who required anterior debridement and fusion one week and two weeks later, respectively. Two other patients with recurrent infection and intractable pain underwent surgical intervention at one month and eight months after PEDD, respectively. The remaining 11 patients recovered uneventfully after full-course, specific, antimicrobial therapy. No surgery related complications or side effects were observed during at least 12 months of follow-up. In conclusion, PEDD can provide retrieval of sufficient specimens and has high diagnostic efficacy, thereby enabling prompt and appropriate antibiotic therapy to the offending pathogens. It can be considered an effective alternative for treating uncomplicated spondylitis.

Adult↗
PubMed2006

Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon autograft: clinical outcome in 4-7 years.

Surgical reconstruction of the anterior cruciate ligament (ACL) is indicated in the ACL-deficient knee with symptomatic instability and multiple ligaments injuries. In the present study, we describe the clinical results of quadriceps tendon-patellar bone autograft for ACL reconstruction. From 1996 to 1998, the graft has been used in 38 patients. Thirty-four patients with complete final follow-up for 4-7 years were analyzed. The average follow-up time was 62 (48-84) months. Thirty-two patients (94%) achieved good or excellent results by Lysholm knee rating. Twenty-six patients (76%) could return to moderate or strenuous activity after reconstruction. Twenty-eight patients (82%) had ligament laxity of less than 2 mm. Finally; 31 patients (91%) were assessed as normal or nearly normal rating by IKDC guideline. Twenty-five patients (73%) had less than 10 mm difference in thigh girth between their reconstructed and normal limbs. Thirty-two (94%) and 31 (91%) patients could achieve recovery of the extensor and flexor muscle strength in the reconstructed knee to 80% or more of normal knee strength, respectively. A statistically significant difference exists in thigh girth difference, extensor strength ratio, and flexor strength ratio before and after reconstruction. Tunnel expansion with more than 1 mm was identified in 2 (6%) tibial tunnels. Our study revealed satisfactory clinical subjective and objective results at 4-7 years follow-up. Quadriceps tendon autograft has the advantage of being self-available, relatively easier arthroscopic technique, and having a suitable size, making it an acceptable graft choice for ACL reconstruction. There is little quadriceps muscle strength loss after quadriceps harvest. A quadriceps tendon-patellar autograft is an adequate graft choice to ACL reconstruction.

Adolescent↗
PubMed2006

Arthroscopic posterior cruciate ligament reconstruction with hamstring tendon autograft: results with a minimum 4-year follow-up.

This study prospectively evaluates the outcomes at a minimum 4-year follow-up after PCL reconstruction using quadruple hamstring tendon autograft with an arthroscopic double fixation technique. During 1996-1999, hamstring tendon autograft graft has been used in 57 patients. Data from 52 patients who had been followed up completely were analyzed. All patients suffered from a grade 3 or higher grade of posterior drawer test and posterior sag sign with MRI image confirmation. Twelve knees had combined posterior and posterolateral instability, which were simultaneously reconstructed. Clinical assessments included Lysholm knee score, International Knee Documentation Committee (IKDC) scores, KT-1000 instrumented test, thigh muscle assessment, and radiographic evaluation. The mean Lysholm score was 54 (40-65) and 91 (65-100) points (P<0.01) before and after surgery. Thirty (58%) patients could return to moderate or strenuous activity. The evaluation of AP translation has been performed with KT-1000. The average posterior displacement measured with KT-1000 was 11.69+/-2.01 mm preoperatively and 3.45+/-2.04 mm postoperatively. Forty-two (81%) patients demonstrated ligament laxity of less than 5 mm. Forty-two (81%) patients were rated as normal or nearly normal based on IKDC scores. Forty-six (88%) patients achieved a minimum of 80% recovery of extensor strength and 44 (85%) patients achieved a minimum of 80% recovery of flexor strength. Statistically significant differences existed in thigh girth, extensor strength, and flexor strength before and after reconstruction. Arthroscopic reconstruction for PCL with four-strand hamstring tendon graft produced satisfactory results. The semitendinosus and gracilis tendon graft is adequate in graft size, technically easier to perform and more reproducible, and had a satisfactory result.

Adult↗
PubMed2006

Prognosis of operative treatment for metastatic hepatocellular carcinoma of the spine.

UNLABELLED: Developing and developed countries have been reported increasing numbers of hepatocellular carcinoma and increased rates of distant metastasis from hepatocellular carcinoma. Data regarding operative treatments and prognoses of hepatocellular carcinoma metastasis to the spine are lacking in the literature. We retrospectively reviewed 12 patients with hepatocellular carcinoma and metastasis to the spine who had spinal surgery between 1986 and 1996. All 12 patients had severe back pain preoperatively. Posterior surgery alone was performed on two patients, anterior surgery alone in six patients, and combined anterior and posterior surgery in four. Ten of the 12 patients experienced pain relief and their neurologic status was preserved or improved. We designed a new outcome assessment, a modified Prolo scale, to evaluate surgical outcome. Seven of the 12 patients had good or excellent results. Our sample size was limited and we could draw no definite conclusions regarding the prognoses of these patients or the value of surgical intervention; however, we think that operative treatment for spinal metastatic hepatocellular carcinoma lesions may improve quality of life, regardless whether the survival time is prolonged. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series--no, or historical, control group). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2006

The effect of interspinous ligament integrity on adjacent segment instability after lumbar instrumentation and laminectomy--an experimental study in porcine model.

Eight fresh porcine lumbar spines received a posterior instrumentation at L4-L5 using pedicle screw-rod system. Each specimen was tested utilizing laminectomies of varying extent. Group A (Integrity) preserved the spinous process and interspinous ligament; Group B (Partial laminectomy) removed the inferior portion of L4 spinous process and preserved the interspinous ligament of L3-L4; Group C (Complete laminectomy) removed the entire L4 spinous process. Hydraulic testing machine was used to generate an increasing moment up to 8400 N mm in flexion and extension. The intervertebral displacement on the superior adjacent disc between L3-L4 was measured using an extensometer. Under extension, no significant difference in the intervertebral displacement was observed among three different models of laminectomy. However, under flexion, the intervertebral displacement on adjacent disc with complete laminectomy was statistically larger than those of integrity and partial laminectomies (P=0.000976 and P=0.0363, respectively). No difference was found between integrity and partial laminectomy groups (P>0.05). This study implies that an instrumented spine with integrity of posterior complex is less likely to develop adjacent instability than a spine with destruction of the anchoring point for supraspinous ligament.

Animals↗
PubMed2005

Long-term results of disc excision for recurrent lumbar disc herniation with or without posterolateral fusion.

STUDY DESIGN: A retrospective study assessing the long-term outcomes of repeat surgery for recurrent lumbar disc herniation. OBJECTIVES: To evaluate the results of repeat surgery for recurrent disc herniation, and compare the results of disc excision with and without posterolateral fusion. SUMMARY OF BACKGROUND DATA: The outcomes of revision surgery varied owing to the mixed patient populations. The optimal technique for treating recurrent disc herniation is controversial. METHODS: The sample included 41 patients who underwent disc excision with or without posterolateral fusion, with an average follow-up of 88.7 months (range, 60-134 months). Clinical symptoms were assessed based on the Japanese Orthopedic Association Back Scores. All medical and surgical records were examined and analyzed, including pain-free interval, intraoperative blood loss, length of surgery, and postsurgery hospital stay. RESULTS: Clinical outcome was excellent or good in 80.5% of patients, including 78.3% of patients undergoing a discectomy alone, and 83.3% of patients with posterolateral fusion. The recovery rate was 82.2%, and the difference between the fusion and nonfusion groups was insignificant (P = 0.799). The difference in the postoperative back pain score was also insignificant (P = 0.461). These two groups were not different in terms of age, pain-free interval, and follow-up duration. Intraoperative blood loss, length of surgery, and length of hospitalization were significantly less in patients undergoing discectomy alone than in patients with fusion. CONCLUSIONS: Repeat surgery for recurrent sciatica is effective in cases of true recurrent disc herniation. Disc excision alone is recommended for managing recurrent disc herniation.

Adolescent↗
PubMed2005

The fusion rate of calcium sulfate with local autograft bone compared with autologous iliac bone graft for instrumented short-segment spinal fusion.

STUDY DESIGN: A prospective study. OBJECTIVES: To compare the efficacy of calcium sulfate pellets plus laminectomy bone chips with a fresh autologous iliac bone graft for short-segment lumbar fusion. SUMMARY OF BACKGROUND DATA: Bone graft substitute material can be used to expand an existing quantity of available laminectomy bone chips. METHODS: Seventy-four patients underwent surgery for instrumented one- or two-segment fusion with decompression. Autologous iliac crest bone graft was placed in one posterolateral gutter, while on the other side, an equal quantity of autogenous laminectomy bone supplemented with calcium sulfate was placed. Radiographic assessment included radiographs alone; this was performed every 3 months (3 months to 12 months), then annually. The status of fusion and the relative size of the fusion bone mass on either side of the vertebra were compared. RESULTS: Using iliac crest bone graft (control side) versus autograft laminectomy bone with calcium sulfate (test side), there was no significant difference between the fusion rate and sizes of the fusion bone mass (P > 0.05). Follow-up periods ranged from 30 months to 34 months, averaging 32.5 months. For the 39 patients who received single-segment fusion, 34 patients (87.2%) exhibited bone fusion on the test side, and 35 patients (89.7%) had evidence of fusion on the control side. For the 35 patients who received two-segment fusion, 29 patients (82.9%) exhibited bone fusion on the test side and 30 patients (85.7%) demonstrated complete fusion on the control side. CONCLUSIONS: The fusion rate and fusion size between the two groups are similar. Calcium sulfate pellets may play a role as a bone graft extender in short-segment spinal fusion.

Adult↗
PubMed2005

Failure analysis of broken pedicle screws on spinal instrumentation.

Revised spinal surgery is needed when there is a broken pedicle screw in the patient. This study investigated the pedicle screw breakage by conducting retrieval analyses of broken pedicle screws from 16 patients clinically and by performing stress analyses in the posterolateral fusion computationally using finite element (FE) models. Fracture surface of screws was studied by scanning electron microscope (SEM). The FE model of the posterolateral fusion with the screw showed that screws on the caudal side had larger axial stress than those on the cephalic side, supporting the clinical findings that 75% of the patients had the screw breakage on the caudal side. SEM fractography showed that all broken screws exhibited beach marks or striations on the fractured surface, indicating fatigue failure. Screws of patients with spinal fracture showed fatigue striations and final ductile fracture around the edge. Among the 16 patients who had broken pedicle screws 69% of them achieved bone union in the bone graft, showing that bone union in the bone graft did not warrant the prevention of screw breakage.

Adult↗
PubMed2005

Maintenance of interbody space in one- and two-level anterior cervical interbody fusion: comparison of the effectiveness of autograft, allograft, and cage.

UNLABELLED: The use of allografts, autologous iliac crest grafts, and cages for anterior cervical fusion is well documented, however there is no comparison regarding the effectiveness of maintaining the interbody space with the three approaches. We retrospectively measured the rate and amount of interspace collapse, segmental sagittal angulations, clinical results, and radiographic fusion success rates to determine which is the best fusion material. We assessed 73 patients who had one- and two-level cervical discectomies and interbody fusions without instrumentation. The three groups had similar clinical results and fusion rates. However, in the autograft group union occurred in 4 months. In the allograft group, union did not occur until 5.54 months. Moreover, the loss of cervical lordosis (2.75 degrees) was less in the cage group than in the allograft group (9.23 degrees). Additionally, the anterior interspace collapse (1.73 mm) in the cage group was less than the collapse recorded in the autograft group (2.82 mm) and in the allograft group (4 mm). An interspace collapse of 3 mm or greater was observed in 56.1% of the patients in the allograft group, compared with only 19% of the patients in the cage group. We showed that the cage is superior to the allograft and autograft in maintaining cervical interspace height and cervical lordosis after one-level and two-level anterior cervical decompression procedures. LEVEL OF EVIDENCE: Therapeutic study, Level III-2 (retrospective cohort study).

Cervical Vertebrae↗
PubMed2005

Unipedicle percutaneous vertebroplasty for spinal intraosseous vacuum cleft.

UNLABELLED: Osteoporotic compression fractures have been widely treated by vertebroplasty through a bipedicle approach. We suspected that a compression fracture with vacuum cleft can be treated successfully with a unipedicle approach. We retrospectively reviewed 27 patients with an osteoporotic compression fracture with intraosseous vacuum cleft. The patients received percutaneous vertebroplasty with bone cement (polymethylmethacrylate) augmentation. Bone cement was injected into the fractured vertebral body through only one cannula in the selected pedicle. Cement filling, vertebral height restoration, and relief of pain were evaluated. The minimum followup was 12 months (range, 12-30 months). Twenty six of 27 patients had adequate filling. Average vertebral height restoration was 27%. The patients' visual analog scale improved an average of 40 points. Percutaneous transpedicle vertebroplasty is effective for treating osteoporotic compression fractures with intraosseous vacuum clefts. Because of the preexistent cleft, the procedure can be done successfully via a unipedicle approach. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series--no, or historical, control group). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2005

Biomechanical analysis of the disc adjacent to posterolateral fusion with laminectomy in lumbar spine.

OBJECTIVES: After posterolateral fusion with laminectomy for the degenerative lumbar spine, accelerated degeneration of the disc adjacent to the fusion mass has been clinically observed. Previous studies used a finite element model (FEM) to calculate the stress of the adjacent disc in the fused lumbar spine with spinal fixator and bone graft. However, little emphasis was placed on the simultaneous spinal fusion and decompression procedure. To investigate if the spinal decompression procedure in posterolateral fusion would increase stress significantly, the FEM was employed to estimate the stress concentration of the disc above the fusion mass in posterolateral fusion with laminectomy and hemilaminectomy. METHODS: Three FEMs of the lumbar spine were established: intact spine, posterolateral fusion with total laminectomy, and posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments). The posterolateral fusion added spinal fixator and bone graft between the transverse process. The L1 vertebral body was subjected to 10-Nm flexion, extension, torsion, and lateral bending. The bottom of the L5 vertebral body was fixed. RESULTS: In flexion, the stress on the adjacent disc in posterolateral fusion with laminectomy and hemilaminectomy respectively increased 90% and 21% over that of the intact spine. In posterolateral fusion with hemilaminectomy, the supraspinous and interspinous ligaments shared some external forces to alleviate the stress concentration of the adjacent disc. However, in extension, torsion, and lateral bending, these two fusion models had almost no change in range of motion and stress of adjacent disc. CONCLUSION: Posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments) was able to alleviate the stress concentration of the disc above the fusion mass in flexion.

Biomechanical Phenomena↗
PubMed2005

Single cylindrical threaded cage used in recurrent lumbar disc herniation.

OBJECTIVES: Where fusion is being considered after repeated discectomy for recurrent lumbar disc herniation (RLDH), interbody fusion is reasonable. But interbody fusion by dual cages inserted posteriorly is difficult because of the scarring from the previous surgery. Under this consideration, a prospective clinical study of RLDH operated on by posterolateral placement of a single cylindrical threaded cage through the virgin side after decompression was conducted. The study is not intended to indicate when to fuse the recurrent herniation but to evaluate the efficacy of this fusion method for these patients whenever fusion is necessary. METHODS: From November 1998 to April 2000, 14 RLDH patients were enrolled after failure of conservative treatment. Eleven patients had a lesion at L4-L5 and three at L5-S1. Two patients experienced disc reherniation on the side opposite the original injury, whereas the subsequent reherniation was ipsilateral for the other 12. CONCLUSIONS: In this series, there was no evidence of dural tears or neurologic deficits, but three temporary superficial wound infections, one urinary tract infection, and one asymptomatic disc wedging were experienced. As for the result of interbody fusion by cage, 12 patients (85.8%) achieved successful fusions; the other two had radiolucency along the cage-endplate interfaces and were therefore defined as failure of interbody fusion. Satisfactory clinical results were achieved for 13 patients (92.9%; excellent [n = 6], good [n = 7]) using this procedure.

Adult↗
PubMed2005

Treatment of undisplaced femoral neck fractures in the elderly.

BACKGROUND: While the treatment for displaced femoral neck fractures in the elderly (Garden types III and IV) is quite clear, the procedure for impacted or undisplaced femoral neck fractures (Garden types I and II) is still a subject of controversy. METHODS: Thirty-seven (all >80 years old) patients with undisplaced femoral neck fractures were treated with osteosynthesis by cannulated screws fixation. The clinical outcomes were followed up retrospectively for at least two years. RESULTS: The overall union rate was 94.59% (35 patients) at 6 months after primary internal fixation. The overall success rate was 83.78% (31 patients), and the overall failure rate was 16.22% (6 patients). CONCLUSIONS: Osteosynthesis with cannulated screws fixation is a simple, safe, economical, and reasonably effective procedure for the treatment of undisplaced femoral neck fractures in patients older than 80 years.

Aged↗
PubMed2005

Incidence and severity of biceps long head tendon lesion in patients with complete rotator cuff tears.

BACKGROUND: Biceps long head tendon lesion is commonly associated with rotator cuff tendon pathology. This study is to determine the pathologic spectrum of biceps long head tendon in surgical cases with complete full thickness rotator cuff tear. METHODS: Between 1993 and 2002, 122 complete rotator cuff tears with surgery were included for the analysis. During surgery, biceps long head tendon was grossly examined or evaluated via arthroscopy. A simplified classification was used to describe the biceps lesion. RESULTS: 50 (41%) patients had type 1 lesion (tendinitis), 10 (8%) patients had type 2 lesion (subluxation), 12 (10%) patients had type 3 (dislocation), 15 (12%) patients had type 4 (partial tear), and 6 patients (5%) had type 5 (complete rupture). The remaining 29 patients (24%) did not have obvious pathology. All chronic rotator cuff tear (> 3 months) were associated with biceps tendon pathology. A rotator cuff tear greater than 5 cm as determined at surgery was strongly associated with an advanced biceps lesion. CONCLUSION: Biceps tendon injuries are associated with complete rotator cuff tears and there may be a causal relationship due to the impingement that occurs. Early identification and repair of rotator cuff lesions may prevent further deterioration of the biceps tendon.

Adult↗
PubMed2005

Trapezoidal titanium cage in anterior cervical interbody fusion: a clinical experience.

BACKGROUND: Use of autogenous bone grafting taken from anterior iliac crest for anterior cervical interbody fusion has been the "gold-standard" for decades. Substitutes for autogenous bone graft continue to be sought to avoid potential donor site morbidity. A titanium-alloy square-shaped hollow cage was applied to facilitate the process of fusion as a bone graft substitute, then assessed in this retrospective clinical study. METHODS: From July 2000 to July 2001, sixty-three discs from fifty-four patients were selected to receive this cage for one or two segments of the cervical spine for anterior cervical interbody fusion. The Japanese Orthopedic Association (JOA) score and Odom's criteria were used to measure the clinical outcome. Postoperative radiographs were analyzed for graft dislodgement, loss of anterior and posterior disc heights, maintenance of lordosis correction, and status of fusion between the cage and endplates to assess their suitability as a grafting substitute. RESULTS: Eighty-seven percent of patients exhibited satisfactory clinical outcome. Successful fusion was obtained in ninety point five percent of operated discs. Partial cage dislodgement was observed in four point eight percent of discs and caused no adverse symptoms. The mean collapse of the anterior and posterior disc heights were 1.73 mm and 0.91 mm, respectively. Moreover, the mean loss of lordosis correction was 2.75 degrees. CONCLUSIONS: Based on this primary clinical experience, the trapezoid-design, titanium-alloy cage provided adequate mechanical support and stability in the disc space and an excellent fusion result without significant subsidence of disc height or any other complications.

Bone Transplantation↗
PubMed2005

Surgical treatment of spinal pseudoarthrosis in ankylosing spondylitis.

BACKGROUND: In ankylosing spondylitis (AS), the spine with osteoporotic changes is fragile and vulnerable to trauma. Patients may develop spinal pseudoarthrosis (SP), whose clinical features are usually misdiagnosed as a tuberculous infection. This study reports our experience with surgical treatment for SP in AS. METHODS: Eight patients with AS and SP at the thoracolumbar area were treated surgically and followed-up for at least 3 years. All had persistent back pain and progressive kyphosis. One patient had neurologic deficits preoperatively. Anterior debridement and interbody fusion followed by posterior stabilization were performed in all patients. A posterior corrective osteotomy was additionally done in 3 patients whose kyphotic angle exceeded 45 degrees. RESULTS: All patients with persistent back pain obtained significant pain relief postoperatively. On a visual analogue scale, there was an average improvement of 43 points on the clinical scores. The patient with neurologic deficits showed improvement after the operation. Solid bony fusion was achieved in an average of 7.5 months, and correction of the kyphotic angle averaged 18.6 degrees. CONCLUSIONS: Spinal pseudoarthrosis should be considered in patients with AS, and must be differentiated from tuberculous and other infections. The results of this study show that pain relief and correction of the kyphotic deformity can be achieved by surgical treatment for ankylosing spondylitis complicated with pseudoarthrosis.

Adult↗
PubMed2005

Pyogenic spondylitis presenting with skip lesions.

We report on a 65-year-old man who presented with a 1-month history of aggravating backache and low-grade fever. He suddenly became paraplegic (Frankel B). Muscle power was grade 0 approximately 1 over the bilateral lower limbs. X-ray films showed disc space narrowing and end-plate blurring at the T9 approximately T11 and L4 approximately L5 levels. Magnetic resonance imaging showed an infectious lesion at T9 approximately T11 and another at L4 approximately L5. An emergent operation was performed under the impression of pyogenic spondylitis with spinal cord compression. The patient showed a significant recovery (Frankel D) after the thoracic and lumbar spinal surgeries. Pyogenic spondylitis usually presents as a vertebra-disc-vertebra lesion spreads to the contiguous vertebra-disc-vertebra unit. The current patient had pyogenic spondylitis with coexistent thoracic and lumbar lesions. This kind of skip lesion is common in spinal malignant metastasis, but rare in spinal infections. Awareness of the possibility of multiple lesions or skip lesions will facilitate the diagnosis and treatment of this condition.

Aged↗