Biomedical subjects

Shih-Tseng Lee

Publications and source records attributed to Shih-Tseng Lee.

At least 19 recordsLinked to original sources

PubMed2006

Clinical experience with rigid occipitocervical fusion in the management of traumatic upper cervical spinal instability.

Traumatic injuries of the craniovertebral junction or the upper cervical spine may result in occipitocervical (OC) or upper cervical spinal instability. Internal fixation can provide immediate stability to this region. Over a 6-year period, 16 patients with traumatic upper cervical spinal instability underwent a posterior approach OC fusion, using a plate and screw system, at the neurosurgical department of our institution. One patient died. The postoperative course of all the other patients was uncomplicated. At the most recent follow-up examination, all patients had satisfactory fusion. OC fusion with a plate and screw system is a safe and effective method for the treatment of traumatic craniovertebral and high cervical spine instability. Accurate imaging diagnosis and strict patient selection are the keys to a successful outcome.

Accidents, Traffic↗

PubMed2006

Classification of symptomatic osteoporotic compression fractures of the thoracic and lumbar spine.

The pathophysiology of osteoporotic compression fractures is different from those occurring secondary to traumatic spinal injury, and currently, there is no classification suitable for symptomatic osteoporotic compression fractures treated by percutaneous vertebroplasty. We propose a new classification based on the radiological appearance in the subacute or chronic stage of the clinical presentation of these fractures. They are classified by the authors based on observations and measurements from preoperative and postoperative dynamic lateral radiographs. Compression fractures are divided into two types. Type I is a compression fracture involving the anterior column only. Type II is a fracture involving both the anterior and middle column. Each type is divided into two groups: fractures with union and those with non-union. Type II compression fractures have a higher incidence of non-union than type I (p<0.05). In both type I and II non-union groups, fractures achieve greater increase in vertebral body height after vertebroplasty than both type I and type II union group fractures (p<0.05). In both non-union groups, fractures achieved a greater reduction of kyphotic angle post-vertebroplasty than type I and II union group fractures (p<0.05). Further clinical follow-up of these patients will confirm and extend this classification.

Body Weight↗

PubMed2006

Unilateral traumatic posterior fossa subdural effusion in an infant.

Supratentorial subdural effusion is common after infection and trauma, but rarely occurs in the posterior fossa, and is even less commonly unilateral. The authors report a rare case of unilateral traumatic posterior fossa subdural effusion with secondary hydrocephalus. A 6-month-old female infant presented with lethargy, poor appetite, and persistent vomiting after head trauma 2 weeks previously. A non-enhanced brain CT scan revealed a right posterior fossa subdural fluid collection that displaced the fourth ventricle and brainstem and dilated lateral ventricles. While monitoring the intracranial pressure, the baby was treated with temporary external subdural drainage, followed by a permanent subdural peritoneal shunt. The treatment and likely physiopathology of this unique case are discussed.

Craniocerebral Trauma↗

PubMed2006

Need for intrasellar packing in sellar reconstruction of transsphenoidal surgery: less is more?

BACKGROUND: This study investigated patients with pituitary macroadenomas who received transsphenoidal surgery using two different sellar reconstruction methods, to determine the need for intrasellar packing. METHODS: The authors reviewed 53 patients with pituitary macroadenomas at a single institution between January 1999 and November 2002. On tumour removal, the group 1 patients underwent traditional sellar reconstruction (intrasellar and sphenoid sinus packing), while the group 2 patients did not undergo intrasellar packing. RESULTS: The two groups did not differ significantly in terms of complications. There was no mortality; notably, no delayed empty sella syndrome occurred in the group 2 patients. CONCLUSIONS: Simplified reconstruction of the sella floor using only sphenoid bone without intrasellar packing is thought to be safe and effective. This technique obviates the need for a second surgical incision, risk of overpacking, complications associated with packing material and interference on postoperative magnetic resonance imaging.

Adenoma↗

PubMed2006

The polymethyl methacrylate cervical cage for treatment of cervical disk disease Part III. Biomechanical properties.

BACKGROUND: In a previous article, we used the PMMA cervical cage in the treatment of single-level cervical disk disease and the preliminary clinical results were satisfactory. However, the mechanical properties of the PMMA cage were not clear. Therefore, we designed a comparative in vitro biomechanical study to determine the mechanical properties of the PMMA cage. METHODS: The PMMA cervical cage and the Solis PEEK cervical cage were compressed in a materials testing machine to determine the mechanical properties. RESULTS: The compressive yield strength of the PMMA cage (7030 +/- 637 N) was less than that of the Solis polymer cervical cage (8100 +/- 572 N). The ultimate compressive strength of the PMMA cage (8160 +/- 724 N) was less than that of the Solis cage (9100 +/- 634 N). The stiffness of the PMMA cervical cage (8106 +/- 817 N/mm) was greater than that of the Solis cage (6486 +/- 530 N/mm). The elastic modulus of the PMMA cage (623 +/- 57 MPa) was greater than that of the Solis cage (510 +/- 42 MPa). The elongation of PMMA cage (43.5 +/- 5.7%) was larger than that of the Solis cage (36.1 +/- 4.3%). CONCLUSIONS: Although the compressive yield strength and ultimate compressive strength of the PMMA cervical cage were less than those of the Solis polymer cage, the mechanical properties are better than those of the cervical vertebral body. The PMMA cage is strong and safe for use as a spacer for cervical interbody fusion. Compared with other cage materials, the PMMA cage has many advantages and no obvious failings at present. However, the PMMA cervical cage warrants further long-term clinical study.

Biomechanical Phenomena↗

PubMed2006

Antibiotic-polymethylmethacrylate strut: an option for treating cervical pyogenic spondylitis. Case report.

Antibiotic-polymethylmethacrylate (PMMA) cement and beads constitute an effective system of local drug delivery of antibiotic agents in patients with bone and soft-tissue infections. Debridement followed by implantation of antibiotic-PMMA beads and systemic administration of antibiotic agents has achieved a 100% success rate in treating chronic osteomyelitis; however, there have been no reports of an antibiotic-PMMA strut for treating spinal pyogenic spondylitis. In this case report we describe a 57-year-old woman with C5-6 pyogenic spondylitis, progressive kyphotic deformity, and neurological deficits. The patient underwent anterior C-5 and C-6 corpectomy and spinal reconstruction in which we used an antibiotic-PMMA strut. The strut was 14 mm in diameter and contained PMMA and vancomycin powder. The operation was technically successful, and no complication related to anesthesia or the surgical procedure occurred. At the 12-month follow-up examination, dynamic radiographs revealed cervical spine stabilization. The patient's neck pain subsided and she recovered neurologically with no residual infection. No antibiotic-PMMA strut dislodgment or failure was identified; however, 9.8% subsidence of the strut into the vertebrae was observed. The long-term outcome in this case requires further evaluation.

Anti-Bacterial Agents↗

PubMed2006

Hollow cylindrical polymethylmethacrylate strut for spinal reconstruction after single-level cervical corpectomy.

OBJECT: This prospective study was conducted to assess the safety of using a cylindrical polymethylmethacrylate (PMMA) strut for fusion and reconstruction of the cervical spine after single-level cervical corpectomy. The authors describe the clinical results obtained in patients after surgery. METHODS: Fifty-four patients underwent single-level cervical corpectomy, fusion, and spinal reconstruction that involved the placement of hollow cylindrical PMMA struts. In each patient, the spine was reinforced with anterior cervical plates. The PMMA struts were filled with autologous bone obtained from the resected vertebral body. Follow-up radiographic evaluation involved plain lateral dynamic radiographs and computed tomography (CT) scans. Neurological status was assessed pre- and postoperatively using the Nurick Scale. A total of 46 patients (85.1%) attended follow-up visits for a minimum of 2 years. Spinal stability was documented in all patients on 12-month plain dynamic lateral radiographs; in 37 patients (80.4%), complete osseous fusion was demonstrated on the 12-month CT reconstructions. In the remaining nine patients, complete fusion had been achieved by 24 months. The overall mean preoperative Nurick grade was 2.94 +/- 0.97, and this improved significantly to 1.71 +/- 0.77 (p < 0.05) by 24 months. There were no complications related to the hollow cylindrical PMMA strut. CONCLUSIONS: The findings of this preliminary study indicate that hollow cylindrical PMMA struts can be safely used in cervical fusion after single-level corpectomy and that the clinical results are satisfactory. The hollow cylindrical PMMA strut is a good substitute for spinal reconstruction and fusion when combined with plate fixation in patients who have undergone anterior cervical single-level corpectomy.

Adult↗

PubMed2006

A VR planning system for craniosynostosis surgery.

The goal of our project is to build a system which could utilize the Virtual Reality (VR) techniques for the pre-operative planning of craniosynostosis. The system includes different modules. We use the tetrahedral volume meshes for the basic structure for the models which surgery is planning on. This paper will describe the procedures of above stages, from the processing of 2D image slices, 3D modeling, smoothing, simplification, and visibility ordering, to volume meshes generation. We have demonstrated the initial results on a variety of stereo devices. The testing results show the processing time is acceptable and the rendering effect is pretty well.

Computer Simulation↗

PubMed2005

Pallidotomy effect on the cortical excitability in patients with severe Parkinson's disease.

Surgical lesions in the medial pallidum have been shown to ameliorate motor deficits in patients with Parkinson's disease (PD). It is believed that interruption of the pallidothalamocortical projections to the motor cortex is required for the satisfactory results. In this report, we adopt cortico-cortical inhibition as the tool to assess the pallidotomy effect on cortical excitability in PD. Interstimulus interval between 1 and 15 msec were investigated. The average peak-to-peak amplitude was measured and calculated at each delay. A total of 8 patients (M:F = 4:4) 54.9 years of age (SD = 9.6) and 10 controls were recruited for the study. In the controls, the inhibitory phenomenon was observed from the 1-msec to the 4-msec delay points and the maximal inhibition was at the 3-msec delay point (33.69% +/- 6.50% of the control response). Mild facilitation was noticed since the 5-msec delay point and thereafter. In patients before operation, a similar trend of inhibition was also observed in the initial 4 msec with the maximal inhibition also at the 3-msec delay point (64.66 +/- 6.77% of the control response). In the postoperative group, the short interstimulus interval inhibition can no longer be observed and the conditioned response was 95.06 +/- 23.68% of the control at the 3-msec delay point. The suppression was gone at and after the 7-msec delay point. Results of repeated-measures analysis of variance show a significant difference among the controls and PD patients before and 3 months after pallidotomy (F = 3.40, P = 0.05). Post hoc examination revealed a significant difference between the controls and PD patients 3 months after pallidotomy at the 3-msec delay point (P = 0.004). However, no correlation was observed between the 3-msec inhibition and the Unified Parkinson's Disease Rating Scale Motor score or the dyskinesia score. The results suggest that pallidotomy can modulate the cortical inhibitory circuitry in patients with PD.

Adult↗

PubMed2005

Continuous regional cerebral blood flow monitoring in the neurosurgical intensive care unit.

The aim of this study was to examine the intracranial pressure (ICP) and regional cerebral blood flow (rCoBF) changes during the acute stage of severe head injury and to improve outcome by modifying treatment modalities using real-time ICP and rCoBF data. Twenty patients with moderate or severe head injury that were monitored in our neurosurgical intensive care unit were included in this study. The changes in ICP, rCoBF and the relationship of ICP/rCoBF were observed. In patients with high ICP and low rCoBF, mannitol improves the rCoBF and decreases the ICP of these patients. When low rCoBF exists, hyperventilation may lead to a rapid further decline of rCoBF, however, some hyperemic brains respond well to hyperventilation treatment. Triple-H therapy is suitable for those with low rCoBF without significantly high ICP, which is an abnormal condition considered to be caused by vasospasm.

Adolescent↗

PubMed2005

Posterior atlantoaxial transpedicular screw and plate fixation. Technical note.

The authors describe a modified posterior atlantoaxial fixation technique for the treatment of reducible atlantoaxial instability, which can be performed simply and easily, and can decrease the risk of vessel and/or neural damage. During an 18-month period, this technique was undertaken in 11 patients with atlantoaxial instability. There was no procedure-related morbidity. The follow-up period ranged from 8 to 18 months (mean 13.2 months). Fusion was documented in all 11 patients, and there was no progression of spinal deformity. This technique can be considered an effective alternative in the treatment of atlantoaxial subluxation.

Adult↗

PubMed2005

Use of a polymethylmethacrylate cervical cage in the treatment of single-level cervical disc disease.

OBJECT: Polymethylmethacrylate (PMMA) bone cement has been used as a spacer in the treatment of patients with cervical disc disease with good long-term outcomes, but solid bone fusion has not been demonstrated in all cases. To achieve cervical interbody fusion, the authors designed a modified PMMA cervical cage that they filled with spongy bone for the treatment of single-level cervical disc herniation. METHODS: Sixty-three patients underwent anterior cervical microdiscectomy and implantation of a PMMA cervical cage filled with autograft cancellous bone and were followed for a minimum of 2 years. The fusion rates were 90.5 and 100% at the 6- and 12-month follow-up examinations, respectively. The mean intervertebral disc height gain was 3.4 +/- 1.9 mm when preoperative and 24-month postoperative values were compared. Neck pain, measured using the Huskissan visual analog scale (0 mm, no pain; 100 mm, worst possible pain), decreased from 71 +/- 13 mm at preoperative baseline to 28 +/- 17 at 6, 23 +/- 19 at 12, and 31 +/- 19 mm at 24 months. Based on the same scale, radicular pain decreased from 83 +/- 15 mm at preoperative baseline to 24 +/- 11 at 6, 27 +/- 13 at 12, and 22 +/- 11 mm at 24 months. The self-rated clinical outcome was excellent in 45 (71.4%) and good in 18 (28.6%) of the 63 patients. CONCLUSIONS: The autograft cancellous bone-filled PMMA cage is safe and effective for cervical interbody fusion in the treatment of single-level cervical disc herniation and monoradiculopathy.

Adult↗

PubMed2005

Midpalmar accurate incision for carpal tunnel release.

BACKGROUND: Carpal tunnel syndrome is the most common entrapment neuropathy in humans today. For patients in whom conservative treatment fails, surgical decompression is indicated. Among the various surgical techniques currently in use, endoscopic techniques are becoming increasingly popular. Due to the rapid postoperative recovery shown after endoscopic operations, midpalmar accurate incision for carpal tunnel release is a comparative alternative. METHODS: From February 1998 through January 2003, 84 patients had undergone 96 midpalmar carpal tunnel releases with accurate skin incisions under regional block or general mask anesthesia. The postoperative evaluations were performed via subjective assessment with a standardized telephone interview over an average follow-up period of 22.4 months. RESULTS: The average operation time was 16 minutes (range, 5 to 40 minutes). A total of 87 hands (91%) had excellent or good recovery in terms of symptom relief (improvement of 70% or greater). The incidence of postoperative sensory morbidity, i.e., pillar pain or scar tenderness, was 7% (7 hands). The motor functional morbidity of a persistent subjective decrease in grip strength was noted in 8% (8 hands), and the mean period for returning to work was 4.5 weeks. In addition, no operation-induced neurovascular or tendinous injury occurred in any patient. CONCLUSIONS: The outcomes were similar to those of endoscopic carpal tunnel release. Based on these results, midpalmar carpal tunnel release with accurate location of skin incision is as effective as any other surgical procedures for carpal tunnel release. Furthermore, it is also a safe and simple procedure.

Adult↗

PubMed2004

Management of acute odontoid fractures with single anterior screw fixation.

The use of anterior odontoid screw fixation has grown in popularity for the management of acute, unstable Anderson and d'Alonzo Type II and rostral Type III odontoid fractures. This study critically reviews our clinical experience of 48 patients with single odontoid screw fixation for the treatment of Type II and Type III odontoid fractures between 1997 and 2001. This series had a complication rate of 10% (malposition rate 6% and non-union rate 4%), with a satisfactory overall fusion rate of 96%. Odontoid screw fixation is technically demanding and requires strict patient selection, thorough preoperative planning and careful surgical technique. In our experience, advanced age should not be considered a contraindication to anterior odontoid screw fixation, as satisfactory results can be obtained in some of these patients. This study also emphasises that sagittally oblique type II fractures are associated with a high rate of fusion failure when treated by anterior odontoid screw fixation, and should be treated with other instrumentation methods, such as posterior atlantoaxial arthrodesis.

Adolescent↗

PubMed2004

A syringe compressor for vertebroplasty: technical note.

OBJECTIVE: Percutaneous vertebroplasty (VP) has become a popular technique to treat osteoporotic vertebral compression fractures and spinal column neoplasms. The consistency of the bone cement mixture during the procedure would appear to be increasing with time, but the physician experiences injection difficulty, and there are also concerns with the limited injection time available for such a procedure. METHODS: We describe a special-design screw-syringe compressor to be used with the ordinary 10 mL Luer-Lok syringe and a short connecting tube for the injection of bone cement during VP. RESULTS: The syringe compressor could yield maximum 2,772 psi compression pressure and could finely control the cement delivery rate to 0.2 mL/ a turn. We have used this technique to treat 296 consecutive patients with 384 vertebral compression fractures who were suffering from disabling back pain refractory to analgesic therapy. Using this technique, the injection time can be prolonged to 12 min and the delivery volume can be better controlled. CONCLUSION: With the aid of the syringe compressor, the cementing material can be accurately and steadily injected as desired by the physician. Bone-cement injection can be better controlled with this syringe compressor. Furthermore, this delivery system would reduce per treatment cost.

Decompression, Surgical↗

PubMed2004

Percutaneous vertebroplasty for treatment of thoracolumbar spine bursting fracture.

OBJECTIVE: Percutaneous vertebroplasty can be very beneficial for patients with vertebral osteoporotic compression fractures. To the best of our knowledge, however, there has been no mention in any literature regarding the use of percutaneous vertebroplasty for the treatment of spinal burst fracture. METHODS: A preliminary study was conducted on 6 patients with traumatic burst fractures of vertebrae treated with percutaneous vertebroplasty starting in June 2000. Fractures involving the anterior and middle columns of the vertebrae and the canal were mildly compressed by the retropulsed bone fragment. However, there was no obvious neurologic deficit in these patients. They initially underwent conservative treatment and thoracolumbar spinal orthosis (TLSO) brace for at least 3 months, but the intractable pain caused patients to be bedridden for prolonged periods of time and limited daily activity. As a result, the patients underwent percutaneous vertebroplasty with polymethylmethacrylate (PMMA) for treatment of spinal burst fractures. RESULTS: Six male patients (mean age: 38.2) who suffered from burst fractures of vertebrae with disabling back pain refractory to analgesic therapy and TLSO brace were treated in this study. The duration of conservation treatment period was 3.5 months to 8 months (mean: 5.2 months). There was no motility. However, 4 vertebrae (66.7%), on radiographs revealed evidence of PMMA leakage through the endplate fracture site into either the disc space or the paravertebral space, without any evident clinical symptoms. No intracanal leakage was seen, and no patient needed a secondary surgical intervention. Pain decreased from 84.3 +/- 5.4 mm at baseline to 34.7 +/- 4.4 mm at the third postoperative day, 30.2 +/- 5.8 at 3 months and 24 +/- 3.5 mm at 12 months. The reduction in pain from baseline to the 3-day and 3 month mark was statistically significant (p < 0.05). The mobility was at least 2 levels of improvement (mean improvement 2.7 points) at 12-months postoperative. CONCLUSION: In highly selective patients, percutaneous vertebroplasty can be an alternative method for the treatment of spinal burst fractures and the prevention of complications from major surgical procedures. However, this procedure still has potential risks and should be employed with extreme caution to prevent extravasation of PMMA into the spinal canal.

Adult↗

PubMed2004

Epidural hematoma of the cervical spine after cervical laminectomy in a patient with ventriculo-peritoneal shunt.

Cervical laminectomy is one of the most common procedures performed in the sitting position. However in the presence of intracranial hypotension, a negative intradural pressure develops when the patients are in the sitting position. They are therefore at risk of developing cervical spinal epidural hematomas after cervical laminectomy. We report a case of a shunted patient who developed an epidural hematoma 3 days after a cervical laminectomy procedure in a seated position when he began to ambulate. When performing a cervical laminectomy procedure on a shunted patient, an upright position should be avoided during the operation. Intra-operative hypercapnia as well as intra- and post-operative intravenous hydration should be maintained in order to increase intradural pressure, preventing the formation of cervical spinal epidural hematoma after cervical laminectomy.

Hematoma, Epidural, Spinal↗

PubMed2004

Percutaneous vertebroplasty for the treatment of burst fractures. Case report.

Percutaneous vertebroplasty is a useful procedure for patients with vertebral osteoporotic compression fractures; however, there has been no mention in the literature of the use of percutaneous vertebroplasty for the treatment of traumatic spinal fractures. The authors report the case of a 33-year-old man who harbored L-1, L-2, and L-5 burst fractures sustained in a work-related accident. The patient was successfully treated by percutaneous vertebroplasty with polymethylmethacrylate. The authors propose this procedure as a useful intervention in selected patients with lumbar burst fractures. The complications associated with major surgical procedures are absent.

Accidents, Occupational↗