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Po-Liang Lai

Publications and source records attributed to Po-Liang Lai.

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

Thoracic ossified meningioma and osteoporotic burst fracture: treatment with combined vertebroplasty and laminectomy without instrumentation: case report.

Although spinal meningioma is a common benign neoplasm, the ossified variant is rare. No more than 20 sporadic cases were reported in the literature between 1977 and January 2005. Recently, the authors treated a patient with a symptomatic ossified meningioma located in the posterior aspect of T-11 and an associated osteoporotic T-11 burst fracture. The tumor was completely removed by T10-11 laminectomy and transpedicular vertebroplasty was performed. The kyphotic deformity of the T-11 burst fracture was partially reduced and maintained for at least 2 months after vertebroplasty and laminectomy. The clinical presentation and management of this case are reported.

Aged↗
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

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

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

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

Autonomic dysreflexia triggered by an unstable lumbar spine in a quadriplegic patient.

A 40 year-old man with C5 complete quadriplegia, had L2-L3 pyogenic spondylitis treated with debridement and fusion of the lumbar spine with left iliac bone graft. Three months later he developed symptoms of autonomic dysreflexia, including headache, cold sweating, and hypertension whenever he was in an upright position. These symptoms resolved after lying down. Roentgenograms of the lumbar spine revealed absorption of the bone graft at the L2-L3 level. A spinal stabilization procedure was done after eight weeks of antibiotic therapy under the impression of unstable spine caused by pyogenic spondylitis. Symptoms were relieved immediately following the surgery. This report may be helpful for physicians caring for quadriplegic patients with autonomic dysreflexia induced by an unstable spine.

Adult↗
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↗
PubMed2004

Relation between laminectomy and development of adjacent segment instability after lumbar fusion with pedicle fixation.

STUDY DESIGN: A retrospective study of 101 patients who had undergone posterolateral lumbar fusion, to analyze the association between adjacent instability and the extent of laminectomy. OBJECTIVES: To investigate the hypothesis that the integrity of the posterior complex (spinous process/supraspinous ligament/spinous process) between the fused segments and the neighboring motion segments significantly influences lumbar spine stability. SUMMARY OF BACKGROUND DATA: Spinal fusion with pedicle fixation accelerates the degeneration of adjacent motion segments. The lowest cranial motion segment is the most common level for the development of adjacent instability. Laminectomy, including removal of the spinous process, supraspinous ligament, interspinous ligament, lamina and ligamentum flavum, jeopardizes the integrity of the posterior complex of the spine. METHODS: This study enrolled 101 patients, followed up for at least 6 years, who had been treated with posterolateral lumbar fusion with pedicle fixation because of lumbar spondylolisthesis. The diagnosis of adjacent instability depended on the dynamic lateral views of the lumbosacral spine during each follow-up. The integrity of the posterior complex was based on the extent of laminectomy and the fusion level. RESULTS: At the cranial adjacent motion segment, 2 of 31 (6.5%) patients with preserved posterior complex integrity between the fused segment and motion segment developed adjacent instability, compared with 17 of 70 (24.3%) without preserved posterior complex integrity. At the caudal adjacent motion segment, none of 13 patients (0%) with preserved integrity developed adjacent instability, compared with 3 of 54 (5.6%) without preserved integrity. CONCLUSIONS: Damaging the integrity of the posterior complex between the fused segments and the neighboring motion segments may jeopardize lumbar spine stability. Sacrificing either the supraspinous ligament or the tendon insertion points on the spinous processes leads to an accelerated development of adjacent instability.

Adult↗
PubMed2004

The effect of sagittal alignment on adjacent joint mobility after lumbar instrumentation--a biomechanical study of lumbar vertebrae in a porcine model.

BACKGROUND: The mechanisms and changes in range of motion of neighboring mobile segment (adjacent level) after the instrumented posterior stabilization are not completely understood. This study aims to investigate the effect of sagittal alignment on the adjacent joint mobility after lumbar instrumentation. METHODS: Eight fresh porcine lumbar spines were instrumented with pedicle screw implants from L2 to L4. Each specimen was tested in three different sagittal alignments. Group A were instrumented in lordotic alignment (lordosis 20 degrees ), Group B in straight alignment (lordosis 0 degrees ), and Group C in kyphotic alignment (kyphosis 20 degrees ). Hydraulic testing machine was used to generate an increasing moment in flexion and extension respectively for each specimen. The vertebral displacement of the disc between L1-L2 and L4-L5 were measured simultaneously with an extensometer. FINDINGS: There were no significant differences in vertebral displacement between the three different sagittal alignments in both the superior and inferior adjacent segments under extension motion. However, under flexion motion, the vertebral displacement on the superior adjacent segment (L1-L2) with kyphotic alignment was statistically larger than that of the straight and lordotic alignments (P = 0.0198 and P = 0.000473 respectively), and no differences were found between the three different sagittal alignments on the inferior adjacent segment (L4-L5). INTERPRETATION: The iatrogenically produced kyphotic lumbar spine by posterior instrumentation might cause larger adjacent joint mobility on the superior adjacent joint as compared to the instrumented lordotic lumbar spine. This study implies that an instrumented spine in lordosis is less likely to develop adjacent instability than a kyphotic spine.

Animals↗
PubMed2004

Computer-assisted fluoroscopic navigation of pedicle screw insertion: an in vivo feasibility study.

BACKGROUND: Accurate placement of pedicle screws is difficult. PATIENTS AND METHODS: We evaluated the feasibility and accuracy of pedicle screw insertion assisted by a real-time, 2-dimensional (2D) image-guided navigation system in 12 patients who underwent thoraco-lumbar and/or lumbar stabilization. 66 pedicle screws were inserted either by senior spine surgeons or residents. The accuracy of positioning of the screws was evaluated using postoperative plain radiographs and thin-cut CT. RESULTS: 61 of the 66 screws were inserted successfully. 5 screw insertions showed structural violations: 4 on the medial and 1 on the lateral pedicle wall. The accuracy was higher in the sagittal plane than in the axial plain. There was no difference between the surgical error rates caused by the senior surgeons and the residents. INTERPRETATION: Using computer-assisted 2D fluoroscopic image navigation, it is possible to achieve reliable and accurate pedicle screw insertion during low thoracic and lumbar spinal surgery.

Adult↗
PubMed2004

Effect of postoperative lumbar sagittal alignment on the development of adjacent instability.

OBJECTIVE: This study investigated the effect of postoperative lumbar sagittal alignment on the development of adjacent segment instability. METHODS: The patients were retrospectively divided into two groups (hypolordotic and hyperlordotic) using the lumbar lordosis on lateral lumbosacral view. Diagnosis of adjacent segment instability depended on the dynamic lateral views of the lumbosacral spine. RESULTS: Thirteen (21.7%) cases developed adjacent segment instability during the 6-year follow-up. The two groups had no significant difference in rates of developing adjacent segment instability. CONCLUSION: Restoring the lordosis of the lumbar curve during one motion segment fusion does not prevent the development of adjacent instability.

Aged↗