Sensorless Based Haptic Feedback Integration In Robot-assisted Pedicle Screw Insertion For Lumbar Spine Surgery: A preliminary cadaveric study.

Pedicle screw fixation is an essential surgical technique for addressing various spinal pathologies, including degenerative diseases, trauma, tumors, neoplasms, and infections. Despite its efficacy, the procedure poses significant challenges, notably the limited visibility of spinal anatomical landmarks and the consequent reliance on surgeon's hand-eye coordination. These challenges often result in inaccuracies and high radiation exposure due to the frequent use of fluoroscopy X-ray guidance. Addressing these concerns, this study introduces a novel approach to pedicle screw insertion by utilizing a robot-assisted system that incorporates sensorless based haptics incorporated 5-DOF surgical manipulation. This innovative system aims to minimize radiation exposure and reduce operating time while improving the surgeon's hand posture capabilities. The developed prototype, expected to be implemented using bilateral control, was tested through preliminary cadaveric experiments focused on the insertion of both percutaneous and open pedicle screws at the L4-L5 level of the lumbar spine. Validation of the Sensorless Haptic Feedback feature was an integral part of this study, aiming to enhance precision and safety. The results, confirmed by fluoroscopic x-ray images, demonstrated the successful placement of two percutaneous and two open pedicle screws, with average position and torque errors of 0.011 radians and 0.054 Nm for percutaneous screws, and 0.0116 radians and 0.0057 Nm for open screws, respectively. These findings underscore the potential of the sensorless haptic feedback in a robot-assisted pedicle screw insertion system to significantly reduce radiation exposure and improve surgical outcomes, marking a significant advancement in spinal surgery technology.

A long-term outcome (up to 29 years) of bilateral iliac wings "bayonet osteotomies" for closure of bladder exstrophy.

BACKGROUND: Several types of pelvic osteotomy techniques have been reported and employed by orthopedic surgeons to enhance the approximation of symphyseal diastasis in bladder exstrophy patients. However, there is limited evidence on a long-term follow-up to confirm which osteotomy techniques provide the most suitable and effective outcomes for correcting pelvic deformities. This study aimed to describe the surgical technique of bilateral iliac bayonet osteotomies for correcting pelvic bone without using fixation in bladder exstrophy and to report on the long-term clinical and radiographic outcomes following the bayonet osteotomies. METHODS: We retrospectively reviewed patients with bladder exstrophy who underwent bilateral iliac bayonet osteotomies with the closure of bladder exstrophy between 1993 and 2022. Clinical outcomes and radiographic pubic symphyseal diastasis measurements were evaluated. From a total of 28 operated cases, eleven were able to attend a special follow-up clinic or were interviewed by telephone by one of the authors with completed charts and recorded data. RESULTS: A total of 11 patients (9 female and 2 male) with an average age at operation of 9.14 ± 11.57 months. The average followed-up time was 14.67 ± 9.24 years (0.75-29), with the average modified Harris Hip score being 90.45 ± 1.21. All patients demonstrated decreased pubic symphyseal diastasis distance (2.05 ± 1.13 cm) compared to preoperative (4.58 ± 1.37 cm) without any evidence of nonunion. At the latest follow-up, the average foot progression angle was externally rotated 6.25° ± 4.79° with full hips ROM, and no patients reported abnormal gait, hip pain, limping, or leg length discrepancy. CONCLUSIONS: Bilateral iliac wings bayonet osteotomies technique demonstrated a safe and successful pubic symphyseal diastasis closure with an improvement both clinically and radiographically. Moreover, it showed good long-term results and excellent patient's reported outcome scores. Therefore, it would be another effective option for pelvic osteotomy in treating bladder exstrophy patients.

Surgical outcome of scoliosis in patients with Marfan syndrome.

PURPOSE: To evaluate clinical and radiographic outcomes after surgical scoliosis correction and posterior instrumented fusion in SMF patients. METHODS: A single-center medical database was reviewed to identify MF patients who presented with scoliosis from 2000 to 2015. Patients who underwent spinal fusion surgery were included. Demographic, operative and clinical data were reviewed, and the preoperative, postoperative, and latest follow-up radiographic parameters were compared. RESULTS: Twelve patients were identified (2 males, 10 females) with an average age at surgery of 14.4 ± 2.6 years. Comorbidities were found in 84.6%. Most patients (90.9%) presented with a right thoracic curve. The average preoperative Cobb angle was 75.6 ± 15.5 degrees. Posterior instrumented spinal fusion was performed in all patients (1 hook/pedicular screw and 11 pedicle screws only). The average follow-up period was 6.8 ± 3.1 years. The mean postoperative Cobb angle after surgery and at the final follow-up was 33.4 ± 18.0 degrees and 35.5 ± 18.4 degrees, respectively. There was a statistically significant difference among the preoperative and postoperative Cobb angles (p < 0.001), but no significant difference among the sagittal angles. Two perioperative complications including superficial wound infection and broken rods were observed. CONCLUSIONS: Posterior scoliosis correction and instrumented spinal fusion resulted in a satisfactory outcome in MF patients. Perioperative complications are not uncommon; however, no neurological complication or spinal decompensation was observed in this study. LEVEL OF EVIDENCE: IV.

Prognostic factors in patients with spinal metastasis: a systematic review and meta-analysis.

BACKGROUND CONTEXT: Incidence of symptomatic spinal metastasis has increased owing to improvement in treatment of the disease. One of the key factors that influences decision-making is expected patient survival. To our knowledge, no systematic reviews or meta-analysis have been conducted that review independent prognostic factors in spinal metastases. PURPOSE: This study aimed to determine independent prognostic factors that affect outcome in patients with metastatic spine disease. STUDY DESIGN: This is a systematic literature review and meta-analysis of publications for prognostic factors in spinal metastatic disease. PATIENT SAMPLE: Pooled patient results from cohort and observational studies. OUTCOME MEASUREMENT: Meta-analysis for poor prognostic factors as determined by hazard ratio (HR) and 95% confidential interval (95% CI). METHODS: We systematically searched relevant publications in PubMed and Embase. The following search terms were used: ("'spinal metastases'" OR "'vertebral metastases'" OR ""spinal metastasis" OR 'vertebral metastases') AND ('"prognostic factors"' OR "'survival'"). Inclusion criteria were prospective and retrospective cohort series that report HR and 95% CI of independent prognostic factors from multivariate analysis. Two reviewers independently assessed all papers. The quality of included papers was assessed by using Newcastle-Ottawa Scale for cohort studies and publication bias was assessed by using funnel plot, Begg test, and Egger test. The prognostic factors that were mentioned in at least three publications were pooled. Meta-analysis was performed using HR and 95% CI as the primary outcomes of interest. Heterogeneity was assessed using the I2 method. RESULTS: A total of 3,959 abstracts (1,382 from PubMed and 2,577 from Embase) were identified through database search and 40 publications were identified through review of cited publications. The reviewers selected a total of 51 studies for qualitative synthesis and 43 studies for meta-analysis. Seventeen poor prognostic factors were identified. These included presence of a neurologic deficit before surgery, non-ambulatory status before radiotherapy (RT), non-ambulatory status before surgery, presence of bone metastases, presence of multiple bone metastases (>2 sites), presence of multiple spinal metastases (>3 sites), development of motor deficit in <7 days before initiating RT, development of motor deficit in <14 days before initiating RT, time interval from cancer diagnosis to RT <15 months, Karnofsky Performance Score (KPS) 10-40, KPS 50-70, KPS<70, Eastern Cooperative Oncology Group (ECOG) grade 3-4, male gender, presence of visceral metastases, moderate growth tumor on Tomita score (TS) classification, and rapid growth tumor on TS classification. CONCLUSIONS: Seventeen independent poor prognostic factors were identified in this study. These can be categorized into cancer-specific and nonspecific prognostic factors. A tumor-based prognostic scoring system that combines all specific and general factors may enhance the accuracy of survival prediction in patients with metastatic spine disease.

Clinical Effectiveness and Safety of Microdecompression in Thai Lumbar Spinal Stenosis Patients.

Background: Microdecompression (MD) is a minimally invasive spine surgery for lumbar spinal stenosis (LSS). However, there was no long-term outcome study of this procedure in Thailand. Objective: The aim of this study was to evaluate the safety, complications, and surgical outcomes in Thai patients who underwent MD for LSS. Material and Method: A single-institution database was reviewed for Thai patients with LSS who underwent MD during the 2005 to 2014 study period. We analyzed demographic data and clinical data, intraoperative and postoperative data, and immediate complications. Oswestry Low Back Disability Index (ODI) and EQ-5D-5L were used to measure outcomes. Results: Seventy patients were enrolled (43 female and 27 male), with an average age of 64.1+10.6 years. Mean operative time was 99.5+31.6 minutes per level. Average length of stay was 5.2+2.8 days. Estimated blood loss was 90.5+65.6 ml. The most common level was L4-5. The average follow-up was 47.5+33.8 months. All postoperative patient-reported outcome measures were statistically significantly improved compared to preoperative measures (p<0.05). Average preoperative and postoperative ODI score was 60.8+20.6 and 15.9+15.7, respectively. Average pre-operative and postoperative EQ-5D-5L scores were 35.2+23.4 and 92.2+10, respectively. Immediate complications were found in 7 patients, including 5 incidental dural tear, 1 epidural hematoma, and 1 superficial wound infection. Late complications were found in 5 patients, including 1 cerebrospinal fluid leakage and 4 additional fusion surgeries. Of note, 14 patients had grade I degenerative spondylolisthesis (DS) before surgery although none of these patients complained of significant back pain. However, 3 of 4 cases that underwent additional fusion had pre-operative DS. Conclusion: Microdecompression surgery was found to be effective for treating patients with degenerative spinal stenosis. This procedure should be cautiously used in patients with spondylolisthesis, even in the absence of significant back pain.

A Prospective Randomized Controlled Trial Comparing Posterolateral Lumbar Fusion With and Without Bone Marrow Concentrate Augmentation in Single-Level Lumbar Spondylolisthesis.

Background: Bone marrow (BM), which is a good source of stem cells and biological factors, has the potential to enhance bone fusion. Simple centrifugation technique is one of the procedures used to concentrate BM aspirate for increasing number of cells. However, there are limited clinical study for using BM concentrate augmentation in spinal fusion. Objective: This study was designed to examine the spinal fusion enhancement effects of bone marrow (BM) concentrate augmentation on poster lateral lumbar fusion (PLF) with autologous local bone graft in terms of both quality and quantity, as compared with a control procedure without BM concentrate augmentation. Material and Method: Twelve patients with L4-L5 spondylolisthesis scheduled for PLF after decompressive laminectomy and pedicle screw instrumentation were included in this study. This prospective randomized controlled trial was conducted at Siriraj Hospital during the 2009 to 2012 study period. Patients were randomly assigned to two groups. One group underwent PLF with local bone graft with BM concentrate augmentation (BM group) and the other group underwent PLF with local bone graft only (non-BM group). Clinical outcomes were evaluated by the Oswestry Disability Index (ODI) preoperatively and at 3 and 6 months after PLF. Bone fusion quality was evaluated by bony bridging on 3D-CT imaging. Fusion mass volumes were measured on quantitative 3D-CT scans at 1 week and 6 months, postoperatively. Results: Clinical outcome scores did not differ between groups. Six-month postoperative 3D-CT imaging showed complete PLF bridging in 58.3% and 100% of patients in the BM and non-BM groups, respectively. PLF mass volumes were decreased at 6 months by 51.1% in the BM group and by 48.5% in the non-BM group. One patient in the BM group had local inflammation at the BM aspiration site. Conclusion: Bone marrow concentrate augmentation in this small randomized controlled trial failed to demonstrate positive effects on autologous local bone graft in posterolateral lumbar fusion relative to both quality and quantity. The high percentage of incomplete bridging should also be noted and further investigated.

Chronic spinal cord injury treated with transplanted autologous bone marrow-derived mesenchymal stem cells tracked by magnetic resonance imaging: a case report.

INTRODUCTION: Intrathecal transplantation is a minimally invasive method for the delivery of stem cells, however, whether the cells migrate from the lumbar to the injured cervical spinal cord has not been proved in humans. We describe an attempt to track bone marrow-derived mesenchymal stem cells in a patient with a chronic cervical spinal cord injury. CASE PRESENTATION: A 33-year-old Thai man who sustained an incomplete spinal cord injury from the atlanto-axial subluxation was enrolled into a pilot study aiming to track bone marrow-derived mesenchymal stem cells, labeled with superparamagnetic iron oxide nanoparticles, from intrathecal transplantation in chronic cervical spinal cord injury. He had been dependent on respiratory support since 2005. There had been no improvement in his neurological function for the past 54 months. Bone marrow-derived mesenchymal stem cells were retrieved from his iliac crest and repopulated to the target number. One half of the total cells were labeled with superparamagnetic iron oxide nanoparticles before transplantation to the intrathecal space between L4 and L5. Magnetic resonance imaging studies were performed immediately after the transplantation and at 48 hours, two weeks, one month and seven months after the transplantation. His magnetic resonance imaging scan performed immediately after the transplantation showed hyposignal intensity of paramagnetic substance tagged stem cells in the subarachnoid space at the lumbar spine area. This phenomenon was observed at the surface around his cervical spinal cord at 48 hours. A focal hyposignal intensity of tagged bone marrow-derived stem cells was detected at his cervical spinal cord with magnetic resonance imaging at 48 hours, which faded after two weeks, and then disappeared after one month. No clinical improvement of the neurological function had occurred at the end of this study. However, at 48 hours after the transplantation, he presented with a fever, headache, myalgia and worsening of his motor function (by one grade of all key muscles by the American Spinal Injury Association impairment scale), which lasted for 48 hours. CONCLUSION: Intrathecal injection of bone marrow-derived stem cells at the lumbar spine level could deliver the cells to the injured cervical spinal cord. Transient complications should be observed closely in the first 48 hours after transplantation. Further study should be carried out to evaluate the result of the treatment.

Risk factors relating to the need for mechanical ventilation in isolated cervical spinal cord injury patients.

BACKGROUND: Cervical spinal cord injuries (SCI) are a major public health problem. Respiratory complications are among the most important causes of morbidity and mortality in patients with cervical SCI, especially respiratory failure. Based on our evaluation of the existing English language literature, few previous studies appear to have reported on risk factors associated with the need for mechanical ventilation in isolated cervical SCI patients who had no concomitant injuries or diseases at the time ofadmission. OBJECTIVE: The purpose of this study was to determine incidence and riskfactors relating to the needfor mechanical ventilation in isolated cervical spinal cord injury (SCI) patients who had no concomitant injuries. MATERIAL AND METHOD: This retrospective study was conducted by reviewing and analyzing the patient data of 66 isolated cervical-SCI patients who were admitted in our hospital between January 1995 andDecember 2009. Patient medical records were reviewed for demographic data, neurological injuries, needfor mechanical ventilation, definitive treatment, complications, and outcomes. Univariate and multivariate analysis were used to identify predisposing risk factors relating to patient dependency on mechanical ventilation. RESULTS: Of the 66patients, 30.3% (20/66) required mechanical ventilation and 22.7% (15/66) were identified as complete cord injury, ofwhich seven sustained injury above CS. Of the patients with complete SCI, 66.7% (10/15) were dependent on mechanical ventilation, as were 85% (6/7) with SCI above C5. All five of the patients with complete-SCI above C5 who received operative treatment were dependent upon mechanical ventilation, postoperatively. Only 19.6% (10/51) of the incomplete injury group required mechanical ventilation. Univariate analysis indicated the following factors as significantly increasing the risk ofventilator dependence: complete SCI (p = 0.001), SCI above C5 level (p = 0.011) and operative treatment (p = 0.008). Multivariate analysis identified the following factors as being predisposing risk factors relating to the need of mechanical ventilation: complete SCI (OR: 12.8; 95% CI 2.4-66.9; p = 0.003), SCI above C5 level (OR: 12.0; 95% CI 2.4-60.2; p = 0.002), and operative treatment (OR: 14.8; 95% CI2.1-106.9;p = 0.008). CONCLUSION: Complete SCI, SCI above C5, and operative treatment were predisposing risk factors relating to the need for mechanical ventilation in isolated cervical SCI patients. The data and findings put forth in this study suggest that these factors may assist in predicting the needfor mechanical ventilation as a long-term treatment for isolated cervical SCI patients.

The effect of epidural low-dose morphine-soaked microfibrillar collagen sponge in postoperative pain control after laminectomy and instrumented fusion: a randomized double-blind placebo-controlled study.

OBJECTIVE: To evaluate the postoperative analgesic effect and postoperative nausea and vomiting (PONV) after using epidural low-dose morphine-soaked microfibrillar collagen sponge (MMCS), as compared with placebo. MATERIAL AND METHOD: A prospective randomized double-blind placebo-controlled study was performed on patients under-going single-level posterior lumbar spinal decompression and instrumented fusion at the Department of Orthopedic Surgery, Siriraj Hospital, between August 2012 and December 2013. Patients were randomly allocated into two groups to receive either an epidural MMCS or an epidural normal saline-soaked microfibrillar collagen sponge (placebo). Intensity ofpain, PONV and total amount of morphine were recorded at 4, 24, 48, and 72 hours, postoperatively. RESULTS: The analgesic effect was enhanced significantly in the epidural MMCS group, as the amount ofmorphine used was statistically less than in the placebo group at 4 and 24 hours (p < 0.05). CONCLUSION: A single low-dose epidural MMCS is effectiveforpain control after posterior lumbar spinal surgery with a low incidence of PONV.

Incidence of symptomatic pulmonary embolism in spinal surgery.

BACKGROUND: Pulmonary embolism (PE) is a serious condition in orthopedic surgery. The incidence of PE, which is a sequelae of VTE in spinal surgery, is quite low. In the limited available published data, incidence rates of PE in spinal surgery are comparable to that of hip or knee arthroplasty surgery. The role of pharmacologic thomboprophylaxis remains controversial in spinal surgery. OBJECTIVE: The present study was designed to evaluate the incidence of symptomatic pulmonary embolism in spinal surgery at a single tertiary care institute. MATERIAL AND METHOD: A retrospective study of the medical records of patients that were diagnosed with symptomatic pulmonary embolism in spinal surgery from 2002-2012. The reviewed data were retrieved from the database of the Faculty of Medicine Siriraj Hospital, Mahidol University in Bangkok, Thailand. RESULTS: Three cases of symptomatic pulmonary embolism were found from 9,184 spinal surgery cases. The incidence rate was 0.033%. There were two patients with lumbar spine surgery and one case with thoracolumnbar surgery. All three cases had different underlying conditions, operations, and clinical course. One case of fatal pulmonary embolism was found in our study. CONCLUSION: Although there is a very low incidence of symptomatic pulmonary embolism, this is a catastrophic condition for affected patients and their families. PE can occur in spinal surgery cases at all levels of severity and complexity, even with no apparent risk factors.

Core decompression with bone marrow injection for the treatment of femoral head osteonecrosis.

BACKGROUND: Core decompression has been recommended in treatment of non-traumatic femoral head necrosis in early stage. Injection with patient's own bone marrow from the iliac crest might promote bone formation in the femoral head. OBJECTIVE: To evaluate the result of patients treated by this technique. MATERIAL AND METHOD: Retrospective review of a series cases by the medical records and radiographic pictures. RESULTS: There were 34 procedures from 32 patients. Mean follow-up time was 24.6 months in stage 2 and 27.8 months in stage 3. Radiographic progression was observed in 76% and 69% of stage 2 and 3. Twenty one percent of stage 2 hips underwent other surgeries when 46% of stage 3 did at last follow-up. Pain relief was observed in all cases after the surgery. CONCLUSION: The proposed technique yielded only fair results. Probably due to most patients had steroid related pathology.

Effect of cervical kyphotic deformity type on the motion characteristics and dynamic spinal cord compression.

STUDY DESIGN: Retrospective analysis of kinematic magnetic resonance images. OBJECTIVE: To provide baseline data on the segmental angular and translational motion of the degenerated cervical spine by subtype of kyphotic cervical deformity and to elucidate the relationship between motion and degree of spinal cord compression. SUMMARY OF BACKGROUND DATA: Kyphotic deformities of the cervical spine are relatively common and are classified as either global or focal. Nevertheless, the effects of kyphotic subtype on cervical segmental motion and degree of spinal cord compression are unknown. METHODS: A total of 1171 symptomatic patients (618 females, 553 males) underwent cervical kinematic magnetic resonance imaging in the neutral, flexion, and extension positions. Cervical spines demonstrating kyphosis were included and classified into 3 groups: (1) "global kyphotic deformity" (C-type) (n = 54); (2) "sigmoid deformity" (S-type) with kyphotic upper and lordotic lower cervical segments (n = 29); and (3) "reverse sigmoid deformity" (R-type) with lordotic upper and kyphotic lower cervical segments (n = 39). Translational motion, angular motion, and degree of spinal cord compression were evaluated for each cervical level along with the changes associated with flexion and extension. RESULTS: In the C- and R-types, angular motion with extension was increased in the upper cervical spine, where there was kyphosis; when compared with the S-type, in which there was lordosis in the upper segments. The results were opposite for flexion angular motion. R-type displayed more translational motion at C3-C4 and C5-C6. Degree of static spinal cord compression of R-type was higher than the others at C3-C4. The dynamic spinal cord compression increased in extension more than flexion in all subtypes. CONCLUSION: Cervical spine studies that aim to investigate kyphotic deformities should make efforts to discern the different subtypes of kyphotic deformities to more accurately characterize and study the effects that the sagittal alignment has on the kinematics of the spine and the degree of spinal cord compression.

Cervical myelopathy from retro-odontoid calcium pyrophosphate dihydrate mass: a case report.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is one of the most common forms of crystal-associated arthropathy in the elderly. However, cervical spine is rarely affected, especially in upper cervical area. There have been previous reported cases of symptomatic retro-odontoid CPPD deposition disease in English literature but this case is the first reported in Thai patients. This is a case report of a 67-year-old man who presented with neck pain with progressive myelopathy. Neurologic examination demonstrated a cervical myelopathy with muscle weakness and sensory disturbance of both extremities. Imaging studies showed extradural retro-odontoid mass compressing the spinal cord. The patient underwent occiput to C3 fusion with plating, posterior arch of atlas resection, transoral odontoidectomy, and mass removal. Histological examination of the mass revealed fibrocartilage tissue and rhomboid shaped crystals that showed positive biferingent in polarized light microscopy consistent with CPPD crystals. After surgery, no complication was found, and his neurological function had improved.

Core decompression and concentrated autologous bone marrow injection for treatment of osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head is a deficiency of blood supply resulting in femoral head collapse and joint destruction. This usually found in young adults as the leading cause of hip arthroplasty. Core decompression has been reported to reduce the bone marrow pressure for treatment of stage I and II of disease. Later, addition of concentrated bone marrow injection was proposed and reported good result. The purpose of the present study was to report the result of core decompression and concentrated bone marrow injection. MATERIAL AND METHOD: Twelve patients with osteonecrosis of femoral head underwent a core decompression and concentrated autologous bone marrow injection. Data of age, sex, underlying disease, risk of osteonecrosis were collected. Patients were followed at 3 months, 6 months, 1 year and then yearly. Radiographic data were recorded. RESULTS: Thirteen hips in 12 patients underwent the procedure. Two cases were excluded due to loss of follow-up. Mean age was 36.2 (12-56). One hip were in stage I, five in stage II and five in stage III. Risk factor included steroid usage in 6 hips and alcohol consumption in 3 hips. Underlying diseases were SLE (5), dermatitis (1), post-traumatic (1). Average nucleated cell from marrow was 91.58 x 10(6)/ml (+/- 55.9). CD34 was 17.25 x 10(6)/ml cells and percentage of recovery of mononuclear cell was 70.4%. Mean follow-up time was 3.6 years (range 1-7 years). All cases had good pain relief initially. At the last followup 8 hips (72%) had progression and 2 underwent surgery. No infection occurred. No adverse effect detected. CONCLUSION: This report showed low success rate of core decompression with concentrated autologous bone marrow grafting. The effect of delayed progression is not clear. However, the procedure appeared to be safe without immediate complication.

Complications in vertebroplasty.

BACKGROUND: Vertebroplasty is one of the minimally invasive surgery that benefit in pain relief from the osteoporotic or malignancy related vertebral compression fractures. However, many literatures reported both asymptomatic and serious complications. The aim of the present study was to summarize, collect data and report the complication ofvertebroplastyfrom our experience at a single institute. MATERIAL AND METHOD: Three hundred and twenty five vertebroplasty procedures from 236 patients performed in our institute were retrospectively reviewed. Data of diagnosis, age at the time of procedure were collected. All complications found were reviewed in detail. RESULTS: Commonly performed procedures were at thoracolumbar junction (51.4%). Osteoporosis was the most common cause of fracture. The present study found 88 (27%) complications with 26 (8%) symptomatic patients. Most common complication was cement leakage, which intervertebral disc was the most common site (42.9). Spinal canal leakage was found in 14 cases (20%). Four out of 14 cases had neurological complications and need further managements. Two cases had neurologic complications from needle injury.Adjacent level collapse found in 13 patients (4%) and remote segment collapse occurred in 5 patients (1.5%). Three had progressive kyphosis required later surgical treatment. One asymptomatic cement pulmonary embolism was found in the present study. CONCLUSION: The complications of vertebroplasty were mostly asymptomatic, but serious complication such as neurologic injury could occur. Vertebroplasty could be considered a quite safe treatment for osteoporotic vertebral fracture. Meticulous technique should be executed during the procedure to avoid the leakage complication.

Minimally invasive lumbar disectomy with the tubular retractor system: 4-7 years follow-up.

BACKGROUND: Herniated nucleus pulposus (HNP) is a common cause of low back pain. The conventional technique could injure to the surrounding structures. The tubular retractor system (METRx-X tube, Medtronic, Inc, Minneapolis, USA) is instrument to improve visualization and limited soft tissue damage for minimal invasive lumbar discetomy. OBJECTIVE: To evaluate the surgical outcomes, complications, reoperation rates and patient satisfaction for using tubular retractor system in lumbar disectomy in long term follow-up at least 4 years. MATERIAL AND METHOD: Forty-five patients who had been operated for lumbar microdisectomy with tubular retractor system between Jan 2004-Dec 2007. Demographic data, ODI, VAS scores of back pain and leg pain were collected at the date of admission, 1st week, 1st month, 3rd month and every 6 months until 48 months follow-up. RESULTS: Forty-two patients (26 males with average age 30.4; range 20-45 years, 16 females with average age 32.6; range 23-54 years) were included in the present study by excluding 3 loss follow-up patients. The average operating time with tubular retractor system was 90.5 (range 60-250) minutes.Average blood loss was about 45 (range 30-100) milliliters. Length of stay in the present study was about 4.6 days (2-10 days). The average size of incision was about 2.4 (range 2.0-3.5) centimeters. The average follow-up time of all cases was 4 years 7 months (4-7 years). The VAS score of back pain was significantly improved at 1st month post-operation (p < or = 0.05). The VAS score of leg pain was significantly improved at 1st week post-operation (p < or = 0.05). The ODI score was significantly improved at 1st month post-operation (p < or = 0.05). The complication rate was about 9.5% (4 patients) and the recurrent disc that need to re-operation rate was about 4.9% (2 patients). CONCLUSION: The tubular retractor system has the advantage over the conventional open technique. The result of operation with the tubular retractor was satisfied by the surgeons and the patients. However, This system is quite expensive and need technological equipment. Besides experience of the surgeons, using tubular retractor system also should be carefully considered for the most benefit to the patients, the surgeons and budgets of the institute.

Predictive value of magnetic resonance imaging in cervical spondylotic myelopathy in prognostic surgical outcome.

OBJECTIVE: Establish the predictive value of magnetic resonance imaging (MRI) for cervical spondylotic myelopathy as being a good operative outcome. MATERIAL AND METHOD: A retrospective study of the 52 consecutive patients with cervical spondylotic myelopathy underwent both magnetic resonance imaging (MRI) cervical spines examination at Siriraj Hospital between January 2005 and June 2007. Surgery was divided into two groups: "Good" operative outcome (35 patients) and "No improvement group" (17 patients). Two neuroradiologists independently identified the MR images data that showed the maximum stenosis on sagittal and axial sections and recorded predictive MRL parameters: T2-weighted signal change of the spinal cord, cross-sectional area of the spinal cord, anteroposterior (AP) diameter of the spinal canal and the spinal cord and AP-compression ratio (AP diameter/transverse diameter of the spinal cord). RESULTS: There were no statistically significant differences between both groups in all parameters. CONCLUSION: The AP-diameter of the spinal canal and spinal cord, AP-compression ratio and signal change of the spinal cord are not useful in predicting prognosis outcome in patients with cervical spondylotic myelopathy. In addition, cross-sectional area of the spinal cord cannot confidentially be used as predictive factor in CSM patients due to many influent factors of surgical outcome. A further prospective study without patient selective bias may offer more definite results to confirm these findings.

A knee model for arthrocentesis simulation.

OBJECTIVES: To produce a knee model for medical students and residents to practice knee aspiration and intra-articular injection. MATERIAL AND METHOD: The model was made of plastic, rubber and silicone that included the lower third of the femur, the upper third of the tibia and the patella. They were fixed on 2 plastic boxes in the anatomical position and the boxes were connected together with 2 small hinge joints. A rubber bag was made in the pattern of synovial space of the knee. Quadriceps, anterior muscles of the leg and patellar tendon were also presented. The model was covered with silicon sheet, representing the skin. Water was used to fill up the synovial bag to simulate joint aspiration via supero-lateral approach with the knee in extension. The model was appraised by 30 medical students, 26 orthopedic residents and 10 orthopedic staff in terms of size, anatomy, physical examination, feeling during aspiration, need of the model in education and commercial use. RESULTS: Most of the medical students, residents and staff (80-90%) were satisfied with the model and rated it as good to very good teaching media. However, the model should come out in different sizes and the synovial bag should be modified to improve the ballotment test. Mass production of the model should be done. CONCLUSION: The knee model is an acceptable teaching model for arthrocentesis simulation with affordable cost.

Surgical reconstruction of exstrophy-epispadias complex: analysis of 13 patients.

BACKGROUND: Because exstrophy-epispadias complex is uncommon and satisfactory surgical reconstruction outcomes are difficult to achieve, the surgical repairs by one surgeon (PS) were analysed over a 14-year period. METHODS: Retrospective analysis was performed on 13 patients with the complex who underwent surgery between January 1986 to August 2000. Cosmesis and continence were evaluated. Complications including wound dehiscence and urethrocutaneous fistula were reported. RESULTS: Of six patients with classical exstrophy who underwent functional bladder closure, all had good cosmesis except one who had partial dehiscence. Four patients with isolated epispadias had satisfactory cosmesis. Urethrocutaneous fistula was found in one boy in the classical exstrophy group. Continence was achieved in three out of four patients who had bladder neck reconstruction. One girl whose bladder neck was severely obstructed after functional bladder closure, had continent catheterizable stoma. CONCLUSION: Functional bladder closure yielded satisfactory cosmetic outcome. Bladder neck reconstruction made the patient dry in 75% of cases.