A Novel Trajectory of C7 Laminar Screws Determined Using Three-Dimensional Computed Tomography and Surgical Simulation Software: Comparison with a Pre-existing Trajectory.

STUDY DESIGN: Examination using three-dimensional screw trajectory software and computed tomographic scans. PURPOSE: To evaluate the feasibility of a novel trajectory for C7 laminar screws and to compare it with an old trajectory. OVERVIEW OF LITERATURE: The previously reported trajectory of C7 laminar screws has a horizontal direction without a fixed target point. Our new trajectory has a cephalad direction with a fixed target point. METHODS: Computed tomographic scans of a total of 50 male and 50 female patients were utilized. The placement of C7 laminar screws was activated employing the new and old trajectories. The success rate, the causes of failure, and the maximum allowable length of each trajectory were compared. RESULTS: Employing the new trajectory, the success rates of the unilaminar and bilaminar screws were 93% and 83%, respectively, which were significantly better than the old trajectory (80%, p<0.0001 and 70%, p=0.0003). The most prevalent cause of failure was laminar cortical breach followed by facet joint violation. The new trajectory also offered significantly longer maximum allowable screw length in unilaminar (32.5±4.3 mm vs. 26.5±2.6 mm, p<0.001), bilaminar cephalic (29.5±3.8 mm vs. 25.9±2.6 mm, p<0.0001) and bilaminar caudal (33.1±2.6 mm vs. 25.8±3.1 mm, p<0.001) screws than the old trajectory. With the new and old trajectories, 70% vs. 6% of unilaminar, 60% vs. 2% of bilaminar caudal, and 32% vs. 4% of bilaminar cephalic screws could be protracted perfectly into the corresponding lateral mass without any laminar cortical or facet joint violation (p<0.0001). CONCLUSIONS: The novel trajectory possesses a substantially higher success rate, longer maximum allowable screw length, and higher chance to be extended into the lateral mass (a condition known as a lamino-lateral mass screw) than the old trajectory.

Accuracy of cannulated pedicle screw versus conventional pedicle screw for extra-pedicular screw placement in dysplastic pedicles without cancellous channel in adolescent idiopathic scoliosis: a computerized tomography (CT) analysis.

PURPOSE: This study aimed at studying the accuracy and safety of extra-pedicular screw insertion for dysplastic pedicles in AIS comparing cannulated screw system versus conventional screw system. METHODS: 104 AIS patients with 1524 pedicle screws were evaluated using CT scan. 302 screws were inserted in dysplastic pedicles using fluoroscopic guidance technique. 155 screws were inserted using a cannulated system (Group 1), whereas 147 screws were inserted using standard screws (Group 2). The pedicle perforations were assessed using a classification by Rao et al.; G0: no violation; G1: <2 mm perforation; G2: 2-4 mm perforation; and G3: >4 mm perforation). For anterior perforations, the pedicle perforations were assessed using a modified grading system (Grade 0: no violation, Grade 1: less than 4 mm perforation; Grade 2: 4 mm to 6 mm perforation; and Grade 3: more than 6 mm perforation). RESULTS: The perforation rate in Group 1 was 4.5% and in Group 2 was 15.6% (p = 0.001). Most of the perforations were anterior perforations (53.3%). The anterior perforation rate in Group 1 was 1.9% compared to 8.8% in Group 2 (p = 0.009). Group 1 has a medial perforation rate of 1.3% compared to Group 2, 6.1% (p = 0.031). The rate of critical pedicle perforation in Group 1 was 2.6% and in Group 2 was 6.8% (p = 0.102). In Group 1, there were no critical medial perforation but there was one G2 lateral perforation, one G2 superior perforation and two G3 anterior perforations. In Group 2, there were three G2 medial perforations, one G2 lateral perforation, one G2 anterior perforation and five G3 anterior perforations. CONCLUSION: Usage of cannulated screw system significantly increases the accuracy of pedicle screw insertion in dysplastic pedicles in AIS.

Surgical Morphometry of C1 and C2 Vertebrae: A Three-Dimensional Computed Tomography Analysis of 180 Chinese, Indian, and Malay Patients.

STUDY DESIGN: Clinical imaging study. PURPOSE: To study the surgical morphometry of C1 and C2 vertebrae in Chinese, Indian, and Malay patients. OVERVIEW OF LITERATURE: C1 lateral mass and C2 pedicle screw fixation is gaining popularity. However, there is a lack of C1-C2 morphometric data for the Asian population. METHODS: Computed tomography analysis of 180 subjects (60 subjects each belonging to Chinese, Indian, and Malay populations) using simulation software was performed. Length and angulations of C1 lateral mass (C1LM) and C2 pedicle (C2P) screws were assessed. RESULTS: The predicted C1LM screw length was between 23.2 and 30.2 mm. The safe zone of trajectories was within 11.0°±7.7° laterally to 29.1°±6.2° medially in the axial plane and 37.0°±10.2° caudally to 20.9°±7.8° cephalically in the sagittal plane. The shortest and longest predicted C2P screw lengths were 22.1±2.8 mm and 28.5±3.2 mm, respectively. The safe trajectories were from 25.1° to 39.3° medially in the axial plane and 32.3° to 45.9° cephalically in the sagittal plane. CONCLUSIONS: C1LM screw length was 23-30 mm with the axial safe zone from 11° laterally to 29° medially and sagittal safe zone at 21° cephalically. C2P screw length was 22-28 mm with axial safe zone from 26° to 40° medially and sagittal safe zone from 32° to 46° cephalically. These data serve as an important reference for Chinese, Indian, and Malay populations during C1-C2 instrumentation.

Feasibility and Outcome of an Accelerated Recovery Protocol in Asian Adolescent Idiopathic Scoliosis Patients.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: The aim of this study was to determine the feasibility of an accelerated recovery protocol for Asian adolescent idiopathic scoliosis (AIS) patients undergoing posterior spinal fusion (PSF). SUMMARY OF BACKGROUND DATA: There has been successful implementation of an accelerated recovery protocol for AIS patients undergoing PSF in the western population. No similar studies have been reported in the Asian population. METHODS: Seventy-four AIS (65 F, 9 M) patients scheduled for PSF surgery were recruited. The accelerated protocol encompasses preoperative regime, preoperative day of surgery counseling, intraoperative strategies, an accelerated postoperative rehabilitation and pain management regime. All patients were operated using a dual attending surgeon strategy. Outcome measures included pain scores at five time intervals, length of stay, and detailed recovery milestones. Any complications or readmissions during the first 4 months postoperative period were recorded. RESULTS: Mean duration of operation was 2.2 ±â€Š0.3 hours with a mean blood loss of 824.3 ±â€Š418.2 mL. No patients received allogenic blood transfusion. The mean length of stay was 3.6 ±â€Š0.6 days. Surgical wound pain score was 6.4 ±â€Š2.1 at 12 hours, which reduced to 5.0 ±â€Š2.0 at 60 hours. Abdominal pain peaked at 36 hours with pain scores 2.4 ±â€Š2.9. First liquid intake was at 5.2 ±â€Š7.5 hours, urinary catheter removal at 18.7 ±â€Š4.8 hours, sitting up at 20.6 ±â€Š9.1 hours, ambulation at 27.2 ±â€Š0.5 hours, consumption of solid food at 32.2 ±â€Š0.5 hours, first flatus at 39.0 ±â€Š0.7 hours, and first bowel movement at 122.1 ±â€Š2.0 hours. The complication rate was 1.4% due to superficial wound infection with one patient failed to comply with the accelerated protocol. CONCLUSION: An accelerated recovery protocol following PSF for AIS is feasible without increasing the complication or readmission rates. The total length of stay was 3.6 days and this is comparable with the outcome in western population. LEVEL OF EVIDENCE: 4.

Usage of Chewing Gum in Posterior Spinal Fusion Surgery for Adolescent Idiopathic Scoliosis: A Randomized Controlled Trial.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: The present study investigated the effectiveness of chewing gum on promoting faster bowel function and its ability to hasten recovery for patients with adolescent idiopathic scoliosis (AIS) after posterior spinal fusion (PSF) surgery. SUMMARY OF BACKGROUND DATA: Sham feeding with chewing gum had been reported to reduce the incidence of postoperative ileus by accelerating recovery of bowel function. METHODS: We prospectively recruited and randomized 60 patients with AIS scheduled for PSF surgery into treatment (chewing gum) and control group. The patient-controlled anesthesia usage, wound pain score, abdominal pain score, nausea score, and abdominal girth were assessed and recorded at 12, 24, 36, 48, and 60 hours postoperatively. The timing for the first fluid intake, first oral intake, sitting up, walking, first flatus after surgery, first bowel opening after surgery, and duration of hospital stay were also assessed and recorded. RESULTS: We found that there were no significant differences (P > 0.05) in patient-controlled anesthesia usage, wound pain score, abdominal pain score, nausea score, and abdominal girth between treatment (chewing gum) and control groups. We also found that there were no significant difference (P > 0.05) in postoperative recovery parameters, which were the first fluid intake, first oral intake, sitting up after surgery, walking after surgery, first flatus after surgery, first bowel opening after surgery, and duration of hospital stay between both groups. The wound pain was the worst at 12 hours postoperatively, which progressively improved in both groups. The abdominal pain progressively worsened to the highest score at 48 hours in the treatment group and 36 hours in the control group before improving after that. The pattern of severity and recovery of wound pain and abdominal pain was different. CONCLUSION: We found that chewing gum did not significantly reduce the abdominal pain, promote faster bowel function, or hasten patient recovery. LEVEL OF EVIDENCE: 1.

Comparison Between Minimally Invasive Surgery and Conventional Open Surgery for Patients With Spinal Metastasis: A Prospective Propensity Score-Matched Study.

STUDY DESIGN: Prospective propensity score-matched study. OBJECTIVE: To compare the outcomes of minimal invasive surgery (MIS) and conventional open surgery for spinal metastasis patients. SUMMARY OF BACKGROUND DATA: There is lack of knowledge on whether MIS is comparable to conventional open surgery in treating spinal metastasis. METHODS: Patients with spinal metastasis requiring surgery from January 2008 to December 2010 in two spine centers were recruited. The demographic, preoperative, operative, perioperative and postoperative data were collected and analyzed. Thirty MIS patients were matched with 30 open surgery patients using propensity score matching technique with a match tolerance of 0.02 based on the covariate age, tumor type, Tokuhashi score, and Tomita score. RESULTS: Both groups had significant improvements in Eastern Cooperative Oncology Group (ECOG), Karnofsky scores, visual analogue scale (VAS) for pain and neurological status postoperatively. However, the difference comparing the MIS and open surgery group was not statistically significant. MIS group had significantly longer instrumented segments (5.5 ±â€Š3.1) compared with open group (3.8 ±â€Š1.7). Open group had significantly longer decompressed segment (1.8 ±â€Š0.8) than MIS group (1.0 ±â€Š1.0). Open group had significantly more blood loss (2062.1 ±â€Š1148.0 mL) compared with MIS group (1156.0 ±â€Š572.3 mL). More patients in the open group (76.7%) needed blood transfusions (with higher average units of blood transfused) compared with MIS group (40.0%). Fluoroscopy time was significantly longer in MIS group (116.1 ±â€Š63.3 s) compared with open group (69.9 ±â€Š42.6 s). Open group required longer hospitalization (21.1 ±â€Š10.8 days) compared with MIS group (11.0 ±â€Š5.0 days). CONCLUSION: This study demonstrated that MIS resulted in comparable outcome to open surgery for patients with spinal metastasis but has the advantage of less blood loss, blood transfusions, and shorter hospital stay. LEVEL OF EVIDENCE: 3.

Minimally Invasive Spinal Stabilization Using Fluoroscopic-Guided Percutaneous Screws as a Form of Palliative Surgery in Patients with Spinal Metastasis.

STUDY DESIGN: Prospective cohort study. PURPOSE: To report the outcome of 50 patients with spinal metastases treated with minimally invasive stabilization (MISt) using fluoroscopic guided percutaneous pedicle screws with/without minimally invasive decompression. OVERVIEW OF LITERATURE: The advent of minimally invasive percutaneous pedicle screw stabilization system has revolutionized the treatment of spinal metastasis. METHODS: Between 2008 and 2013, 50 cases of spinal metastasis with pathological fracture(s) with/without neurology deficit were treated by MISt at our institution. The patients were assessed by Tomita score, pain score, operation time, blood loss, neurological recovery, time to ambulation and survival. RESULTS: The mean Tomita score was 6.3±2.4. Thirty seven patients (74.0%) required minimally invasive decompression in addition to MISt. The mean operating time was 2.3±0.5 hours for MISt alone and 3.4±1.2 hours for MISt with decompression. Mean blood loss for MISt alone and MISt with decompression was 0.4±0.2 L and 1.7±0.9 L, respectively. MISt provided a statistically significant reduction in visual analog scale pain score with mean preoperative score of 7.9±1.4 that was significantly decreased to 2.5±1.2 postoperatively (p=0.000). For patients with neurological deficit, 70% displayed improvement of one Frankel grade and 5% had an improvement of 2 Frankel grades. No patient was bed-ridden postoperatively, with the average time to ambulation of 3.4±1.8 days. The mean overall survival time was 11.3 months (range, 2-51 months). Those with a Tomita score <8 survived significantly longer than those a Tomita score ≥8 with a mean survival of 14.1±12.5 months and 6.8±4.9 months, respectively (p=0.019). There were no surgical complications, except one case of implant failure. CONCLUSIONS: MISt is an acceptable treatment option for spinal metastatic patients, providing good relief of instability back pain with no major complications.

Is neck tilt and shoulder imbalance the same phenomenon? A prospective analysis of 89 adolescent idiopathic scoliosis patients (Lenke type 1 and 2).

PURPOSE: To introduce a new clinical neck tilt grading and to investigate clinically and radiologically whether neck tilt and shoulder imbalance is the same phenomenon in AIS patients. METHODS: 89 AIS Lenke 1 and 2 cases were assessed prospectively using the new clinical neck tilt grading. Shoulder imbalance and neck tilt were correlated with coracoid height difference (CHD), clavicle\rib intersection distance (CRID), clavicle angle (CA), radiographic shoulder height (RSH), T1 tilt and cervical axis. RESULTS: Mean age was 17.2 ± 3.8 years old. 66.3 % were Lenke type 1 and 33.7 % were type 2 curves. Strong intraobserver (0.79) and interobserver (0.75) agreement of the clinical neck tilt grading was noted. No significant correlation was observed between clinical neck tilt and shoulder imbalance (0.936). 56.3 % of grade 3 neck tilt, 50.0 % grade 2 neck tilt patients had grade 0 shoulder imbalance. In patients with grade 2 shoulder imbalance, 42.9 % had grade 0, 35.7 % grade 1, 14.3 % grade 2 and only 7.1 % had grade 3 neck tilt. CHD, CRID, CA and RSH correlated with shoulder imbalance. T1 tilt and cervical axis measurements correlated with neck tilt. CONCLUSIONS: In conclusion, neck tilt is distinct from shoulder imbalance. Clinical neck tilt has poor correlation with clinical shoulder imbalance. Clinical neck tilt grading correlated with cervical axis and T1 tilt whereas clinical shoulder grading correlated with CHD, RSH CRID and CA.

Efficacy of a Topical Gelatin-Thrombin Matrix Sealant in Reducing Postoperative Drainage Following Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective fusion level(s)-, age-, and gender-matched analysis. PURPOSE: To determine whether the application of a topical gelatin-thrombin matrix sealant (Floseal) at the end of anterior cervical discectomy and fusion (ACDF) can reduce the amount of postoperative hemorrhage. OVERVIEW OF LITERATURE: The effect of the matrix sealant in decreasing postoperative hemorrhage following ACDF has not been reported. METHODS: Matrix sealant was (n=116, study group) or was not applied (n=58, control group) at the end of ACDF. Patients were selected by 1:2 matching criteria of fusion level(s), age, and gender. Seven parameters described below were compared between the two groups. RESULTS: The total drain amount for the first 24 hours (8±9 versus 27±22 mL), total drain amount until the 8-hour drainage decreased to ≤10 mL (8±10 versus 33±26 mL), and the total drain amount until 6 AM on the first postoperative day (7±8 versus 24±20 mL) were significantly lower in the study group than the control group (all p<0.001). The time for the 8-hour drainage to decrease to ≤10 mL was significantly lower in the study group (10±5 versus 26±14 hours, p<0.001). The 8-hour drainage decreased to ≤10 mL on the operation day in most patients (88%) in the study group versus mostly on the first (48%) or second (33%) postoperative day in the control group (p<0.001). The total drain amount until 6 AM on the first postoperative day was 0 mL in 43% of patients in the study group and in 7% in the control group (p<0.001). No patient in either group required hematoma evacuation. CONCLUSIONS: Application of the topical matrix sealant at the end of ACDF can significantly reduce the amount of postoperative hemorrhage.

Ultra Long Construct Minimally Invasive Spinal Stabilization Using Percutaneous Pedicle Screws in the Treatment of Symptomatic Multicentric Spinal Metastasis.

Managing multiple level spinal metastases is challenging. We report the case of a 58-year-old female with advanced lung cancer who presented with multiple pathological fractures of the thoracic spine (T5, T6, T7, and T8 vertebrae). She was treated with palliative radiotherapy. Her resting pain improved, but the instability pain persisted. One month later, she had a trivial fall leading to a pathological fracture of the L2 vertebra with cauda equine syndrome. The patient was treated surgically with minimally invasive decompression of the L2 and with percutaneous instrumented stabilization using an ultra-long construct from T3 to L5 (15 spinal levels), spanning the previously radiated zone and the decompression site. Postoperatively, she had significant improvements in pain and neurology. There were no surgical complications. Ultra long construct minimally invasive spinal stabilization is the ideal approach for symptomatic multicentric spinal metastasis with poor prognostic scores. Using this technique, the goals of spinal stabilization and direct neural decompression can be achieved with minimal morbidity.

Accuracy and safety of fluoroscopic guided percutaneous pedicle screws in thoracic and lumbosacral spine: a review of 2000 screws.

STUDY DESIGN: Retrospective study. OBJECTIVE: To investigate the accuracy and safety of percutaneous pedicle screws placed using fluoroscopic guidance in the thoracic and lumbosacral spine. SUMMARY OF BACKGROUND DATA: Several studies had examined the accuracy and safety of percutaneous pedicle screws but provided large variations in their results with small number of patients or few number of pedicle screws evaluated. METHODS: Computerized tomography of patients who had surgery with fluoroscopic guided percutaneous pedicle screws were chosen from 2 centers: (1) European patients from University Medical Center Hamburg-Eppendorf, Germany and (2) Asian patients from University Malaya Medical Centre, Malaysia. Screw perforations were classified into Grade 0, Grade 1 (<2 mm), Grade 2 (2-4 mm), and Grade 3 (>4 mm). RESULTS: In total, 2000 percutaneous pedicle screws from 273 patients were analyzed: 1290 screws from 183 European patients and 710 screws from 90 Asian patients. The mean age was 59.1 ± 15.6. There were 140 male patients and 133 female patients. The total perforation rate was 9.4% with 151 (7.5%) Grade 1, 31 (1.6%) Grade 2, and 5 (0.3%) Grade 3 perforations. The total perforation rates among Europeans were 9.4% and among Asians were 9.3%. There was no difference between the 2 groups (P > 0.05). There were 3 distinct peaks in perforation rates (trimodal distribution) at T1, midthoracic region (T4-T7), and lumbosacral junction (L5 and S1). The highest perforation rates were at T1 (33.3%), S1 (19.4%), and T4 (18.6%). CONCLUSION: Implantation of percutaneous pedicle screws insertion using fluoroscopic guidance is safe and has the accuracy comparable to open techniques of pedicle screws insertion. LEVEL OF EVIDENCE: 4.

Femoral head diameter in the Malaysian population.

INTRODUCTION: Hip arthroplasty is commonly performed worldwide. The objective of this study was to determine the diameter of the femoral head in the Malaysian population in relation to gender and race (i.e. among Malay, Chinese and Indian patients). METHODS: This was a retrospective cross-sectional study performed between January 1995 and December 2006, evaluating the femoral head diameters of all patients aged 50 years and above who underwent hemiarthroplasty at two major hospitals in Malaysia. RESULTS: A total of 945 femoral heads (663 women, 282 men) were evaluated. The mean age of the patients in our cohort was 75.2 ± 9.4 (range 50-101) years. The mean femoral head diameter (with intact articular cartilage) was 44.9 ± 3.2 (range 38-54) mm. In our study, men had a significantly larger mean femoral head diameter than women (47.7 ± 2.8 mm vs. 43.7 ± 2.4 mm; p < 0.05). Patients of Chinese ethnicity were also found to have significantly larger femoral head diameters, when compared among the three races studied (p < 0.05). CONCLUSION: Malaysians have a mean femoral head diameter of 44.9 ± 3.2 mm. Among our patients, Chinese patients had a significantly larger femoral head size than Malay and Indian patients. We also found that, in our cohort, men had significantly larger femoral head diameters than women.