The Anatomical Relationship Between the Cervical Nerve Roots, Intervertebral Discs and Bony Cervical Landmark for Posterior Endoscopic Cervical Foraminotomy and Discectomy: A Cadaveric Study.

STUDY DESIGN: Cadaveric anatomical studies. OBJECTIVE: This study aims to investigate the anatomical relationship between bony landmark "V point", dural sac, nerve roots, and intervertebral disc for improving operative outcomes and decreasing post-operative complications in posterior endoscopic cervical foraminotomy or discectomy (PECF or PECD). METHOD: 10 soft adult cadavers were studied. We measured the distance of the V point to the lateral margin of dural sac, V point to the inferior border of intervertebral disc, and the inferior border of cervical nerve root to the inferior border of intervertebral disc. Then we calculated the mean of distance from V point to the inferior border of cervical nerve root. RESULT: The mean distance from the V point to the lateral margin of dural sac from C3/4 to C7/T1 ranged from 3.1 ± 1.38 mm to 3.37 ± 1.46 mm. The mean distances from V point to the inferior border of intervertebral disc from C3/4 to C7/T1 were .19 ± 1.16 mm at C3/4, .45 ± 1.23 mm at C4/5, .43 ± 1.01 at C5/6, -.43 ± 1.86 mm at C6/7 and -1.5 ± 1.2 mm at C7/T1. The mean distance between V point and the inferior border of cervical nerve root from C3/4 to C7/T1 showed all positive value, ranging from .06 ± 1.18 mm to 4.45 ± 2.57 mm, increasing caudally. CONCLUSION: In performing PECF or PECD, a 3-4 mm radius of bone removal should be enough for exposure and neural decompression at C3/4 to C5/6. At C6/7 and C7/T1 a more extensive bone cut of more than 4 mm is recommended, especially in cranial direction.

Survey research of patient's preference on choosing microscopic or endoscopic spine surgery for lumbar discectomy.

BACKGROUND: There are several surgical methods of lumbar discectomy which provide the similar clinical outcomes. There is no clear evidence for how to select the procedures. To better understand the patient's opinion and decision process in the selection of surgical methods between microscopic lumbar discectomy (MLD) and endoscopic lumbar discectomy (ELD). METHODS: A cross-sectional survey study. Summary information sheet was created by reviewing the comparative literatures, and tested for quality and bias. Participants read the summary information sheet then were asked to complete the anonymous questionnaire. RESULTS: Seventy-six patients (71%) of patients who had no experience in lumbar discectomy selected ELD while 31 patients (29%) selected MLD. There were significant differences of score between patients who selected MLD and ELD in this group for wound size, anesthetic method, operative time, blood loss and length of stay (P< 0.05). In patients who had experience in discectomy group, 22 patients (76%) who underwent MLD still selected MLD if they could select surgical methods again for themselves, while 24 patients (96%) who underwent ELD still selected ELD if they could select again. The most important factor in patients who selected MLD was outcomes of treatment. The most important factor in patients who selected ELD was wound size. There were significant differences of scores between patients who selected MLD and ELD in this group for wound size, anesthetic method, operative time, complication, cost and length of stay (P< 0.05). CONCLUSIONS: About two thirds of the participants preferred ELD after reading the summary evidence information. The most important factor in MLD group was outcomes of treatment while the most important factor in ELD group was wound size.

Predictive factors for respiratory failure and in-hospital mortality after surgery for spinal metastasis.

PURPOSE: Spinal metastasis surgeries carry substantial risk of complications. PRF is among complications that significantly increase mortality rate and length of hospital stay. The risk factor of PRF after spinal metastasis surgery has not been investigated. This study aims to identify the predictors of postoperative respiratory failure (PRF) and in-hospital death after spinal metastasis surgery. METHODS: We retrospectively reviewed consecutive patients with spinal metastasis surgically treated between 2008 and 2018. PRF was defined as mechanical ventilator dependence > 48 h postoperatively (MVD) or unplanned postoperative intubation (UPI). Collected data include demographics, laboratory data, radiographic and operative data, and postoperative complications. Stepwise logistic regression analysis was used to determine predictors independently associated with PRFs and in-hospital death. RESULTS: This study included 236 patients (average age 57 ± 14 years, 126 males). MVD and UPI occurred in 13 (5.5%) patients and 13 (5.5%) patients, respectively. During admission, 14 (5.9%) patients had died postoperatively. Multivariate logistic regression analysis revealed significant predictors of MVD included intraoperative blood loss > 2000 mL (odds ratio [OR] 12.28, 95% confidence interval [CI] 2.88-52.36), surgery involving cervical spine (OR 9.58, 95% CI 1.94-47.25), and ASA classification ≥ 4 (OR 6.59, 95% CI 1.85-23.42). The predictive factors of UPI included postoperative sepsis (OR 20.48, 95% CI 3.47-120.86), central nervous system (CNS) metastasis (OR 10.21, 95% CI 1.42-73.18), lung metastasis (OR 7.18, 95% CI 1.09-47.4), and postoperative pulmonary complications (OR 6.85, 95% CI 1.44-32.52). The predictive factors of in-hospital death included postoperative sepsis (OR 13.15, 95% CI 2.92-59.26), CNS metastasis (OR 10.55, 95% CI 1.54-72.05), and postoperative pulmonary complications (OR 9.87, 95% CI 2.35-41.45). CONCLUSION: PRFs and in-hospital death are not uncommon after spinal metastasis surgery. Predictive factors for PRFs included preoperative comorbidities, intraoperative massive blood loss, and postoperative complications. Identification of risk factors may help guide therapeutic decision-making and patient counseling.

Validation of Traditional Prognosis Scoring Systems and Skeletal Oncology Research Group Nomogram for Predicting Survival of Spinal Metastasis Patients Undergoing Surgery.

Background: Many scoring systems that predict overall patient survival are based on clinical parameters and primary tumor type. To date, no consensus exists regarding which scoring system has the greatest predictive survival accuracy, especially when applied to specific primary tumors. Additionally, such scores usually fail to include modern treatment modalities, which influence patient survival. This study aimed to evaluate both the overall predictive accuracy of such scoring systems and the predictive accuracy based on the primary tumor. Methods: A retrospective review on spinal metastasis patients who were aged more than 18 years and underwent surgical treatment was conducted between October 2008 and August 2018. Patients were scored based on data before the time of surgery. A survival probability was calculated for each patient using the given scoring systems. The predictive ability of each scoring system was assessed using receiver operating characteristic analysis at postoperative time points; area under the curve was then calculated to quantify predictive accuracy. Results: A total of 186 patients were included in this analysis: 101 (54.3%) were men and the mean age was 57.1 years. Primary tumors were lung in 37 (20%), breast in 26 (14%), prostate in 20 (10.8%), hematologic malignancy in 18 (9.7%), thyroid in 10 (5.4%), gastrointestinal tumor in 25 (13.4%), and others in 40 (21.5%). The primary tumor was unidentified in 10 patients (5.3%). The overall survival was 201 days. For survival prediction, the Skeletal Oncology Research Group (SORG) nomogram showed the highest performance when compared to other prognosis scores in all tumor metastasis but a lower performance to predict survival with lung cancer. The revised Katagiri score demonstrated acceptable performance to predict death for breast cancer metastasis. The Tomita and revised Tokuhashi scores revealed acceptable performance in lung cancer metastasis. The New England Spinal Metastasis Score showed acceptable performance for predicting death in prostate cancer metastasis. SORG nomogram demonstrated acceptable performance for predicting death in hematologic malignancy metastasis at all time points. Conclusions: The results of this study demonstrated inconsistent predictive performance among the prediction models for the specific primary tumor types. The SORG nomogram revealed the highest predictive performance when compared to previous survival prediction models.

Perioperative and Radiographic Outcomes Between Single-Position Surgery (Lateral Decubitus) and Dual-Position Surgery for Lateral Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation: Meta-Analysis.

OBJECTIVE: Lateral lumbar interbody fusion (LLIF) and percutaneous posterior screw fixation (PPSF) techniques is used to treat degenerative lumbar pathologies. Dual-position (DP) lumbar surgery involves repositioning the patient from the supine or lateral decubitus position to prone for posterior fixation. Single-position (SP) lumbar surgery is commonly performed nowadays, a minimally invasive alternative performed entirely from the lateral decubitus position. However, controversy still exists. This meta-analysis aimed to compare perioperative outcomes between SP lumbar surgery and DP lumbar surgery for LLIF and PPSF. METHODS: We conducted this meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched Medline and Scopus from inception to November 11, 2021, for relevant studies. RESULTS: Six studies were identified, which contained totals of 502 and 447 patients in the SP and DP groups, respectively. The unstandardized mean difference in operative time, length of hospital stay, intraoperative blood loss, radiation doses, lumbar lordosis, and pelvic incidence-lumbar lordosis mismatch were -86.1 (95% confidence interval [CI] -149.2 to -23.1) minutes, -1.6 (95% CI -2.4 to -0.9) days, -55.6 (95% CI -127.5 to 16.2) mL, -30.3 (95% CI -80.5 to 19.8) mGy, 1.34 (95% CI -1.17 to 3.86) degrees, and -4.06 (95% CI -5.65 to -2.47) lower in SP when compared with DP. The chances of having complications and reoperations in SP were 0.75 (95% CI 0.49-1.14) and 0.77 (95% CI 0.44-1.36) times, respectively, compared with the DP group. No significant differences were found for intraoperative blood loss, radiation dose, lumbar lordosis, complications, and reoperations between the 2 groups. CONCLUSIONS: This meta-analysis found that SP have lower operative time and length of hospital stay compared with DP LLIF and PPSF. However, no differences in intraoperative blood loss, radiation dose, radiographic change, complications, and reoperation rates were found.

Surgeons' Perspective, Learning Curve, Motivation, and Obstacles of Full-Endoscopic Spine Surgery in Thailand: Results From A Nationwide Survey.

Objective: To report a nationwide survey of the endoscopic spine surgeons across Thailand. Furthermore, the survey will be focused on the perspective of experience, learning curve, motivations, and obstacles at the beginning of their practices. Materials and Methods: The online survey consisting of 16 items was distributed to spine surgeons who are performing endoscopic spine surgery in Thailand via the Google forms web-based questionnaire to investigate participants' demographics, backgrounds, experience in endoscopic spine surgery, motivations, obstacles, and future perspectives. The data was recorded from January 7, 2020 to January 21, 2022. Descriptive statistics were used for analysis. Results: A total of 42 surveys were submitted by 6 neurosurgeons (14.3%) and 36 orthopedic surgeons (85.7%). From the surgeons' perspective, the average number of cases that should be performed until one feels confident, consistently good outcomes, and has minimal complications was 27.44 ± 32.46 cases. For surgeons who starting the endoscopic spine practice, at least 3 workshop participation is needed. Personal interest (39 selected responses) and trending marketing or business purpose (25 selected responses) were the primary motivators for endoscopic spine surgery implementation. Lack of support (18 selected responses) and afraid of complications (16 selected responses) were pertinent obstacles to endoscopic spine surgery implementation. Conclusions: The trend of endoscopic spine surgery has continued to grow in Thailand, shown by the rate of implementation of endoscopic spine surgery reported by Thai spine surgeons. The number of appropriate cases until one feels confident was around 28 cases. The primary motivator and obstacles were personal interest and lack of support.

Effect of Multimodal Drugs Infiltration on Postoperative Pain in Split Laminectomy of Lumbar Spine: A Randomized Controlled Trial.

STUDY DESIGN: A randomized, double-blinded controlled trial. OBJECTIVE: This study tested the effect of single-dose wound infiltration with multiple drugs for pain management after lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Patients undergoing spine surgery often experience severe pain especially in early postoperative period. We hypothesized that intraoperative wound infiltration with multiple drugs would improve outcomes in lumbar spine surgery. METHODS: Fifty-two patients who underwent one to two levels of spinous process splitting laminectomy of lumbar spine, were randomized into two groups. Infiltration group received intraoperative wound infiltration of local anesthetics, morphine sulfate, epinephrine, and nonsteroidal anti-inflammatory drugs at the end of surgery, and received patient-controlled analgesia (PCA) postoperatively. The control group received only PCA postoperatively. The primary outcome measures were amount of morphine consumption and visual analogue scale (VAS) for pain. The secondary outcome measures were Oswestry Disability Index (ODI), Roland-Morris Low Back Pain and Disability Questionnaire (RMDQ), patient satisfaction, length of hospital stay, and side effects. RESULTS: A total of 49 patients (23 patients for local infiltration group, and 26 patients for control group) were analyzed. There were statistically significant [P < 0.001, the effect size -5.0, 95% CI (-6.1, -3.9)] less morphine consumptions in the local infiltration group than the control group during the first 12 hours, 12 to 24 hours, and 24 to 48 hours after surgery. The VAS of postoperative pain reported by patients at rest and during motion was significantly lower in the local infiltration group than the control group at all assessment times (P < 0.001). The effect size of VAS of postoperative pain at rest and during motion were -2.0, 95% CI (-2.5, -1.4) and -2.0, 95% CI (-2.6, -1.4) respectively. ODI and RMDQ at 2 week and 3 month follow-ups in both groups had significant improvement from baseline (P < 0.001). No significant differences were found between groups (P = 0.262 for ODI and P = 0.296 for RMDQ). There were no significant differences of patient satisfaction, length of stay, and side effects between both groups (P = 0.256, P = 0.262, P = 0.145 respectively). CONCLUSION: Intraoperative wound infiltration with multimodal drugs reduced postoperative morphine consumption, decreased pain score with no increased side effects. LEVEL OF EVIDENCE: 1.

AOSpine Consensus Paper on Nomenclature for Working-Channel Endoscopic Spinal Procedures.

STUDY DESIGN: International consensus paper on a unified nomenclature for full-endoscopic spine surgery. OBJECTIVES: Minimally invasive endoscopic spinal procedures have undergone rapid development during the past decade. Evolution of working-channel endoscopes and surgical instruments as well as innovation in surgical techniques have expanded the types of spinal pathology that can be addressed. However, there is in the literature a heterogeneous nomenclature defining approach corridors and procedures, and this lack of common language has hampered communication between endoscopic spine surgeons, patients, hospitals, and insurance providers. METHODS: The current report summarizes the nomenclature reported for working-channel endoscopic procedures that address cervical, thoracic, and lumbar spinal pathology. RESULTS: We propose a uniform system that defines the working-channel endoscope (full-endoscopic), approach corridor (anterior, posterior, interlaminar, transforaminal), spinal segment (cervical, thoracic, lumbar), and procedure performed (eg, discectomy, foraminotomy). We suggest the following nomenclature for the most common full-endoscopic procedures: posterior endoscopic cervical foraminotomy (PECF), transforaminal endoscopic thoracic discectomy (TETD), transforaminal endoscopic lumbar discectomy (TELD), transforaminal lumbar foraminotomy (TELF), interlaminar endoscopic lumbar discectomy (IELD), interlaminar endoscopic lateral recess decompression (IE-LRD), and lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD). CONCLUSIONS: We believe that it is critical to delineate a consensus nomenclature to facilitate uniformity of working-channel endoscopic procedures within academic scholarship. This will hopefully facilitate development, standardization of procedures, teaching, and widespread acceptance of full-endoscopic spinal procedures.

Comparison of Complications and Revisions After Sacral 2 Alar Iliac Screw and Iliac Screw Fixation for Sacropelvic Fixation in Pediatric and Adult Populations: Systematic Review and Meta-Analysis.

OBJECTIVE: This systematic review and meta-analysis aims to assess and compare the postoperative outcomes of iliac screw (IS) fixation versus sacral 2 alar iliac (S2AI) screw fixation in the adult and pediatric populations. METHODS: We searched all comparative studies that compared postoperative outcomes of IS and S2AI fixation techniques for pelvic fixation from the PubMed and Scopus databases up to June 23, 2019. RESULTS: Eleven of 951 studies (N = 632 patients) were eligible; 8, 10, 5, 6, 3, 7, 2, and 2 studies were included in pooling of postoperative complications, revisions, implant failure, screw breakage, screw prominence, wound dehiscence, wound infection, visual analog scale (VAS), and ambulatory status (AS), respectively. The IS technique had a statistically significant higher chance of postoperative complications, revisions, implant failure, screw breakage, screw prominent, wound dehiscence, and wound infection by 1.89 (95% confidence interval [CI], 1.48-2.40), 1.91 (95% CI, 1.29-2.82), 2.28 (95% CI, 1.55-3.35), 3.96 (95% CI, 1.46-10.75), 6.83 (95% CI, 2.54-18.37), 4.62 (95% CI, 1.32-16.25), and 3.03 (95% CI, 1.62-5.66), respectively compared with the S2AI fixation technique. In subgroup analysis, the IS technique had a statistically significant higher chance of postoperative complications and revisions of 1.65 (95% CI, 1.25-2.16) and 1.71 (95% CI, 1.03-2.84) in pediatric populations and 2.32 (95% CI, 1.60-3.38) and 1.94 (95% CI, 1.00-3.73) in the adult populations compared with the S2AI fixation technique. IS screw fixation had a lower AS of -0.40 (95% CI, -0.76 to -0.15) than did S2AI fixation in the adult and pediatric populations. However, there was no difference in pain VAS between both groups. CONCLUSIONS: Sacropelvic fixation with IS screw fixation had more postoperative complications and revisions and lower AS than did S2AI fixation.

Malposition of Cage in Minimally Invasive Oblique Lumbar Interbody Fusion.

INTRODUCTION: Minimally invasive oblique lumbar interbody fusion is one of the novel lateral lumbar interbody fusion techniques for which the successful early results have been reported. However, new complications were increasingly reported from ongoing studies. CASE PRESENTATION: We report a case of an unusual complication of minimally invasive oblique lumbar interbody fusion associated with contralateral nerve root compression due to deep and posterior position of polyetheretherketone cage and discussion of the operating technique for repositioning polyetheretherketone cage. CONCLUSION: Malposition of polyetheretherketone cage can cause contralateral nerve root compression and neurological complication. The surgical technique to proper pull the polyetheretherketone cage back into the acceptable position should be considered and well prepared.

Comparative Outcomes of Perioperative Epidural Steroids After Percutaneous Endoscopic Lumbar Discectomy for Lumbar Disc Herniation: A Randomized Placebo-Controlled Trial.

OBJECTIVE: To assess postoperative outcomes and complications after percutaneous endoscopic lumbar discectomy (PELD) with or without epidural steroids (ES) administration in lumbar disc herniation. METHODS: In a double-blind randomized, placebo-controlled trial at Ramathibodi Hospital, Mahidol University, from May 2014 to May 2015, 30 patients were randomly allocated to receive ES or placebo (saline) after PELD. The primary outcome was 24-hour morphine consumption. Secondary outcomes were visual analog scale (VAS) scores for leg and back pain, Oswestry Disability Index score, Roland-Morris Disability Questionnaire score, and complications at 6-month follow-up. RESULTS: Mean patient age was 60.0 years, and 0.57% of patients were male. Mean VAS back pain, VAS leg pain, Oswestry Disability Index, and Roland-Morris Disability Questionnaire scores at baseline were 4.7, 6.1, 24.9, 17.5 in the ES group and 5.1, 5.5, 24.7, 16.7 in the placebo group, respectively. Mean morphine requirements measured at 8, 16, and 24 hours were 3.47, 2.67, and <0.001 in the ES group and 3.13, 1.67, and 0.40 in the placebo group. The mean VAS scores measured at 4, 8, 12, 16, 20, and 24 hours were 2.99, 2.70, 2.56, 3.30, 3.05, and 2.05 the ES group and 3.13, 1.13, 1.26, 1.65, 1.22, and 1.08 in placebo group. The difference was not statistically significant (P > 0.05 for all). CONCLUSIONS: Administration of ES with PELD for lumbar disc herniation does not improve postoperative pain, morphine requirements, or disability scores in the short-term and midterm periods.

The short and midterm outcomes of lumbar transforaminal epidural injection with preganglionic and postganglionic approach in lumbosacral radiculopathy: a systematic review and meta-analysis.

The purpose of this study was to compare clinical outcomes after preganglionic versus ganglionic epidural steroid injection (ESI) using a systematic review and network meta-analysis. A systematic review and meta-regression was performed to compare postoperative outcomes between the two difference injection techniques. Relevant randomized controlled trials were identified from Medline and Scopus up to September 24, 2016. Sixteen out of 598 studies were eligible; 3, 2, and 3 studies were included in the pooling of outcomes including effectiveness, visual analog score (VAS), and complications (nerve root, injury, dural puncture, and intraneural injection). Preganglionic ESI has a 2.38 (95% CI 1.12, 5.04) times statistically significantly higher chance of effectiveness when compared to ganglionic ESI. There were differences in pain VAS and complications in lumbar radiculopathy, but these displayed no statistical significance. This meta-analysis indicated that preganglionic ESI has a statistically significantly higher chance of effectiveness when compared to ganglionic ESI. In terms of pain score and complications, there were no statistically significant differences between the two groups. These results were generally homogeneous and with little publication bias, thus should be generalizable.

Clinical outcomes after minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion for treatment of degenerative lumbar disease: a systematic review and meta-analysis.

The surgical procedures used for arthrodesis in the lumbar spine for degenerative lumbar diseases remain controversial. This systematic review aims to assess and compare clinical outcomes along with the complications and fusion of each technique (minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or minimally invasive lateral lumbar interbody fusion (MIS LLIF)) for treatment of degenerative lumbar diseases. Relevant studies were identified from Medline and Scopus from inception to July 19, 2016 that reported Oswestry Disability Index (ODI), back and leg pain visual analog score (VAS), postoperative complications, and fusion of either technique. Fifty-eight studies were included for the analysis of MIS-TLIF; 40 studies were included for analysis of LLIF, and 1 randomized controlled trial (RCT) study was included for comparison of MIS-TLIF to LLIF. Overall, there were 9506 patients (5728 in the MIS-TLIF group and 3778 in the LLIF group). Indirect meta-analysis, MIS-TLIF provided better postoperative back and leg pain (VAS), disabilities (ODI), and risk of having complications when compared to LLIF technique, but the fusion rate was not significantly different between the two techniques. However, direct meta-analysis between RCT study and pooled indirect meta-analysis of MIS-TLIF have better pain, disabilities, and complication but no statistically significant difference when compared to LLIF. In LLIF, the pooled mean ODI and VAS back pain were 2.91 (95% CI 2.49, 3.33) and 23.24 (95% CI 18.96, 27.51) in MIS approach whereas 3.14 (95% CI 2.29, 4.04) and 28.29 (95% CI 21.92, 34.67) in traditional approach. In terms of complications and fusion rate, there was no difference in both groups. In lumbar interbody fusion, MIS-TLIF had better ODI, VAS pain, and complication rate when compared to LLIF with direct and indirect meta-analysis methods. However, in terms of fusion rates, there were no differences between the two techniques.

Comparative Outcomes of Cortical Screw Trajectory Fixation and Pedicle Screw Fixation in Lumbar Spinal Fusion: Systematic Review and Meta-analysis.

PURPOSE: We conducted a systematic review and meta-analysis to compare the postoperative outcomes of cortical screw and pedicle screw (PS) fixation techniques for posterior lumbar interbody fusion (PLIF). METHOD: We searched all comparative studies that compared postoperative outcomes of cortical screw and PS fixation techniques for lumbar spinal fusions from the PubMed and Scopus databases up to 2 October 2016. RESULTS: Eight of 1147 studies (N = 466 patients) were eligible: 5 back pain Visual Analog Scale (VAS); 4 leg pain VAS; 3 Oswestry Disability Index; 2 Japanese Orthopaedic Association scale; 5 intraoperative complications (dural tear and misplacement); 6 postoperative complications (hematoma, infection, adjacent segment disease and fracture); and 4 fusion rate studies were included. The unstandardized mean difference of back and leg pain VAS and Oswestry Disability Index of cortical bone trajectory (CBT) screw fixation was -0.14 (95% confidence interval [CI]: -2.46, 2.19), -0.46 (95% CI: -1.21, 0.29), and -1.64 (95% CI: -4.17, 0.89) scores lower than PS fixation for PLIF, but without statistical significance. Whereas PLIF with CBT screw fixation was insignificant higher Japanese Orthopaedic Association score of 0.87 (95% CI: -0.06, 1.81) when compared with PS fixation. CBT had a statistically significantly lower chance of postoperative complications by 0.49 (95% CI: 0.25, 0.95) when compared with PS fixation technique. However, CBT had no insignificant lower chance of intraoperative complication by 0.82 (95% CI: 0.28, 2.41) when compared with the PS technique. CONCLUSIONS: PLIF with CBT screw fixation had postoperative back and leg pain, disabilities, and function score.

Anatomic Considerations of Intervertebral Disc Perspective in Lumbar Posterolateral Approach via Kambin's Triangle: Cadaveric Study.

STUDY DESIGN: Anatomical study. PURPOSE: To evaluate the anatomy of intervertebral disc (IVD) area in the triangular working zone of the lumbar spine based on cadaveric measurements. OVERVIEW OF LITERATURE: The posterolateral percutaneous approach to the lumbar spine has been widely used as a minimally invasive spinal surgery. However, to our knowledge, the actual perspective of disc boundaries and areas through posterolateral endoscopic approach are not well defined. METHODS: Ninety-six measurements for areas and dimensions of IVD in Kambin's triangle on bilateral sides of L1-S1 in 5 fresh human cadavers were studied. RESULTS: The trapezoidal IVD area (mean±standard deviation) for true working space was 63.65±14.70 mm2 at L1-2, 70.79±21.88 mm2 at L2-3, 99.03±15.83 mm2 at L3-4, 116.22±20.93 mm2 at L4-5, and 92.18±23.63 mm2 at L5-S1. The average dimension of calculated largest ellipsoidal cannula that could be placed in IVD area was 5.83×11.02 mm at L1-2, 6.97×10.78 mm at L2-3, 9.30×10.67 mm at L3-4, 8.84×13.15 mm at L4-5, and 6.61×14.07 mm at L5-S1. CONCLUSIONS: The trapezoidal perspective of working zone of IVD in Kambin's triangle is important and limited. This should be taken into consideration when developing the tools and instruments for posterolateral endoscopic lumbar spine surgery.

Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation.

BACKGROUND: Cervical pedicle screw (CPS) insertion is a technically demanding procedure. The quantitative understanding of cervical pedicle morphology, especially the narrowest part of cervical pedicle or isthmus, would minimize the risk of catastrophic damage to surrounding neurovascular structures and improve surgical outcome. The aim of this study was to investigate morphology and quantify cortical thickness of the cervical isthmus by using Multi-detector Computerized Tomography (MD-CT) scan. METHODS: The cervical CT scans were performed in 74 patients (37 males and 37 females) with 1-mm slice thickness and then retro-reconstructed into sagittal and coronal planes to measure various cervical parameters as follows: outer pedicle width (OPW), inner pedicle width (IPW), outer pedicle height (OPH), inner pedicle height (IPH), pedicle cortical thickness, pedicle sagittal angle (PSA), and pedicle transverse angle (PTA). RESULTS: Total numbers of 740 pedicles were measured in this present study. The mean OPW and IPW significantly increased from C3 to C7 while the mean OPH and IPH of those showed non-significant difference between any measured levels. The medial-lateral cortical thickness was significantly smaller than the superior-inferior one. PTA in the upper cervical spine was significantly wider than the lower ones. The PSA changed from upward inclination at upper cervical spine to the downward inclination at lower cervical spine. CONCLUSIONS: This study has demonstrated that cervical vertebra has relatively small and narrow inner pedicle canal with thick outer pedicle cortex and also shows a variable in pedicle width and inconsistent transverse angle. To enhance the safety of CPS insertion, the entry point and trajectories should be determined individually by using preoperative MD-CT scan and the inner pedicle width should be a key parameter to determine the screw dimensions.

Outcomes of fluoroscopically guided lumbar transforaminal epidural steroid injections in degenerative lumbar spondylolisthesis patients.

STUDY DESIGN: A prospective cohort. PURPOSE: To report the short and long term outcomes of fluoroscopically guided lumbar transforaminal epidural steroid injection (TFESI) in degenerative lumbar spondylolisthesis (DLS) patients. OVERVIEW OF LITERATURE: TFESI has been widely used for the treatment of lumbosacral radicular pains. However, to our knowledge, there has been no study which has evaluated the outcomes of TFESI in patients with DLS. METHODS: The DLS patients received fluoroscopically guided lumbar TFESI with 80 mg of methylprednisolone and 2 mL of 1% lidocaine hydrochloride. Patients were evaluated by an independent observer before the initial injection, at 2 weeks, at 6 weeks, at 3 months, and at 12 months after the injections. Visual analog scale (VAS), Roland 5-point pain scale, standing tolerance, walking tolerance, and patient satisfaction scale were evaluated for outcomes. RESULTS: Thirty three DLS patients treated with TFESI, who were completely followed up, were included in this study. The average number of injections per patient was 1.9 (range from 1 to 3 injections per patient). Significant improvements in VAS and Roland 5-point pain scale were observed over the follow up period from 2 weeks to 12 months. However, the standing and walking tolerance were not significantly improved after 2 weeks. At 2 weeks, the patient satisfaction scale was highest, although, these outcomes declined with time. The DLS patients with one level of spinal stenosis showed significantly better outcome than the DLS patients with two levels of spinal stenosis. Five patients (13%) underwent surgical treatment during the 3 to 12 months follow up. CONCLUSIONS: TFESI provides short term improvements in VAS and Roland 5-point pain scale, standing tolerance, walking tolerance and patient satisfaction scale in DLS patients. In the long term, it improves VAS but limits the improvements in Roland 5-point pain scale, standing tolerance, walking tolerance and patient satisfaction scale.

BMP induced inflammation: a comparison of rhBMP-7 and rhBMP-2.

Concern has been raised because of reports of inflammatory swelling following the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human bone morphogenetic protein-7 (rhBMP-7). The purpose of this study is to compare the inflammatory action of rhBMP-7 with those of rhBMP-2. ELISA assays (IL-6, TNF-α) were used to measure the cytokine response to different concentrations of rhBMP-7 and -2. Recombinant human BMP-7 was absorbed into absorbable collagen sponges and different amounts were implanted either subcutaneously (SC) or intramuscularly (IM) into the backs of rats. Using MRI and MIPAV software, we measured the degree of soft tissue edema at 3 h and at 2, 4, and 7 days postoperatively. After sacrificing rats on day 7 the inflammatory zone and mass were measured and the tissue examined histologically. Soft tissue edema after rhBMP-7 and rhBMP-2 implantation was dose-dependent and peaked at 3 h for the subcutaneous implants and at 2 days for the intramuscular implants. RhBMP-7 was associated with a significantly smaller soft tissue edema volume than was rhBMP-2 only at the highest dose (20 µg/ml). Both rhBMP-2 and rhBMP-7 triggered dose-dependent inflammatory reactions. Compared to rhBMP-2, rhBMP-7 is associated with somewhat smaller soft tissue edema volumes. Although rhBMP-7 is associated with an inflammatory reaction leading to soft tissue edema, at high doses this response is significantly less than that seen with rhBMP-2. Our animal model can be used to test materials that could ameliorate this reaction.

Bone morphogenetic protein-binding peptide reduces the inflammatory response to recombinant human bone morphogenetic protein-2 and recombinant human bone morphogenetic protein-7 in a rodent model of soft-tissue inflammation.

BACKGROUND CONTEXT: Bone morphogenetic protein (BMP)-2 and BMP-7 are used to enhance bone formation in spine surgery, but the use of these materials is associated with side effects including inflammation, especially in the soft tissues of the neck. Bone morphogenetic protein-binding peptide (BBP) binds BMP-2 and BMP-7 and imparts a "slow-release" property to collagen carrier. PURPOSE: To test the hypothesis that the addition of BBP will reduce the soft-tissue inflammation induced by the implantation of BMP-2 and BMP-7 on a collagen sponge. STUDY DESIGN/SETTING: Prospective in vivo rodent model of inflammation. METHODS: We implanted six different materials absorbed onto collagen sponges: absorbable collagen sponge (ACS) alone; BBP alone; recombinant human bone morphogenetic protein (rhBMP)-2 alone; rhBMP-2 plus BBP; rhBMP-7 alone; and rhBMP-7 plus BBP. Sponges were implanted bilaterally (subcutaneously [SC] and intramuscularly [IM]) into the backs of rats. Using magnetic resonance imaging, inflammation was assessed in terms of soft-tissue edema volume at 3 hours and at 2, 4, and 7 days. The animal subjects were killed on Day 7, and the dimensions of the inflammatory mass were measured manually in the case of SC tissue and those of the inflammatory zone were determined subsequently by microscopic examination in the case of muscle. RESULTS: Both the SC and the IM soft-tissue edema volumes in the rhBMP-2 plus BBP and the rhBMP-7 plus BBP groups were significantly lower than those observed in the rhBMP-2 alone and rhBMP-7 alone groups. The edema volume associated with BBP alone was greater than that associated with ACS alone but less than that associated with the other treatment groups. The measurements of inflammatory masses and zone yielded similar results. CONCLUSIONS: Bone morphogenetic protein-binding peptide may reduce the inflammatory response associated with the use of rhBMP-2 and rhBMP-7 in a rodent model of inflammation and in a form that has previously been shown to enhance the activity of BMPs. These preliminary studies suggest that BBP may have the potential to be used in the future to improve healing and reduce soft-tissue swelling in surgical applications of BMPs.