Qingsong Fu

Radiation exposure to surgeon in minimally invasive transforaminal lumbar interbody fusion with novel spinal locators.

Study Design: A prospective study. Objective: To further investigate the implication of our surface locator and intradermal locator to reduce the radiation exposure to surgeons in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. Summary of Background Data: Our previous studies published in the journal have introduced our novel spinal locators effectively minimizing fluoroscopic time during minimally invasive spinal surgery. Methods: Twenty patients underwent MIS-TLIF surgery with G-arm fluoroscopy from January 2013 to June 2013. There were 10 patients in group A who underwent standard MIS-TLIF using our spinal locators, and the other 10 in group B underwent conventional MIS-TLIF without spinal locators. The radiation dosages to the arm, the finger, the whole body, thyroid gland, gonad gland, and the eye of the surgeon were measured by thermoluminescence badges for both groups. Results: All 20 patients (9 male, 11 female), aged from 48 to 77 years old, successfully underwent the surgery. The operation time was 171.20±10.28 minutes for group A and 189.80±11.99 minutes for group B. The fluoroscopy time was 49.60±7.32 seconds for group A and 68.40±7.62 seconds for group B, hence a reduction of 27.49% was observed. There was no correlation between operation time and exposure time for group A or group B. The radiation reduction was 35.28% for the arm, 17.95% for the finger, 45.23% for the whole body, 53.62% for the thyroid gland (protected), 52.44% for the thyroid gland (unprotected), 44% for gonad gland (protected), 36.42% for the gonad gland (unprotected), 59.42% for the eye (protected), and 59.70% for the eye (unprotected). Conclusion: The study indicated that radiation exposure to the surgeon would be effectively reduced in MIS-TLIF using our surface locator and intradermal locator, and it could be another practical choice for radiation-minimizing strategy.

Preoperative localization methods for minimally invasive surgery in lumbar spine: comparisons between a novel method and conventional methods.

Study Design: This is a prospective single-center nonrandomized control clinical study involving 220 patients who underwent the novel localization method or conventional methods preoperatively in a minimally invasive surgery in lumbar spine. Objective: To introduce a novel preoperative locator designed by the authors for a minimally invasive surgery in lumbar spine and to compare the novel localization method with conventional methods in mean localization time and the mean number of C-arm fluoroscopy use preoperatively. Summary of Background Data: Conventional localization methods for minimally invasive surgery in lumbar spine are associated with more fluoroscopy time and radiation exposure. We describe a novel preoperative locator to help localize spinal anatomic landmarks, minimize preoperative localization time, and decrease radiation exposure. There have been no prospective clinical reports published on the comparison of the novel localization method with conventional methods. Methods: A total of 220 patients, 86 (39.1%) men and 134 (60.9%) women with an average age of 53.8±16.4 years were prospectively evaluated. We divided all patients into 2 groups. Group A: the first 100 patients who received the conventional preoperative localization methods (the palpation method and the Kirschner wire method). Group B: the remaining 120 patients who localized the spinal levels with the help of the novel locator before surgery. The localization time and the number of C-arm fluoroscopy use preoperatively were recorded. Results: The mean localization time of patients in groups A and B were 7.37±3.77 and 3.85±2.45 minutes, respectively. The mean number of preoperative C-arm fluoroscopy use in groups A and B were 2.29 and 1.29. There was significant difference in mean localization time and the mean number of C-arm fluoroscopy use between groups A and B (P<0.05). There was no incidence of wrong-level surgery in both groups. Conclusions: The novel preoperative locator is a simple and practical device that can help to minimize preoperative localization time and decrease radiation exposure.

Percutaneous Pedicle Screw Placement in the Lumbar Spine: A Comparison Study Between the Novel Guidance System and the Conventional Fluoroscopy Method.

Study Design: The clinical study was conducted on 145 patients who received either a novel guidance method or a conventional fluoroscopic method for the percutaneous pedicle screw placement in the lumbar spine. Objective: The aim of this study was to introduce a novel guidance method for percutaneous pedicle screw placement and to compare it with the conventional fluoroscopic method. Summary of Background Data: Conventional fluoroscopic method was associated with a long screw placement and a more fluoroscopy time. The novel guidance system effectively minimized the insertion and the radiation exposure times. Methods: A total of 145 patients were divided into 2 groups. A total of 65 patients (group A) underwent 152 percutaneous pedicle screw fixation by conventional fluoroscopic method. A total of 80 patients (group B) underwent 185 percutaneous pedicle screw fixation by a novel guidance method. Age, body mass index, and sex ratio were comparable between the 2 groups (P>0.05). The time of insertion, radiation exposure, and accuracy of the screw placement between the 2 groups were compared. Results: The mean time for a single pedicle screw placement was found to be 15.11±3.32 minutes in group A and 10.35±2.82 minutes in group B, respectively. The average radiation exposure was 9.06±2.15 s in group B and 13.07±3.06 s in group A, respectively. The differences were statistically significant for both screw placement and radiation exposure times (P<0.05). A total of 131 screws (86.2%) in group A and 163 screws (88.1%) in group B were perfectly located within the pedicle. The statistical difference was not significant (&khgr;2=0.277, P=0.598). Conclusions: The novel guidance system significantly reduced the insertion time and radiation exposure, provided the screw placement was accurately performed when compared with the conventional method.

Morphometric analysis of the working zone for posterolateral endoscopic lumbar discectomy based on magnetic resonance neurography.

Study Design: A magnetic resonance neurography (MRN)-based morphometric analysis of the working zone for posterolateral endoscopic lumbar discectomy (PELD) procedures on 32 health volunteers. Objective: The purpose is to utilize MRN as a noninvasive evaluation of the Kambin’s working zone, and further to analyze operative safety of the PELD procedures. Summary of Background Data: Intraoperative nerve root injuries of PELD procedures occur relative to the Kambin’s triangular working zone, which has been described previously based on formalin-fixed cadaver studies. However, the investigation in living individuals is not known. Thus, it is necessary to evaluate the dimensions of the working zone on both coronal and sagittal plane by radiologic assessments. Materials and Methods: MRN images of 32 health volunteers (average age 26.8 y; 18 men, 14 women) were analyzed from L1–L2 to L5–S1. On the coronal plane, we measured the distance from the superior endplate to the nerve root exiting from the dura (distance a), the distance from lateral aspect of the dura to the medial aspect of the nerve root along the superior endplate (distance b), and the angle between the nerve root and plane of the corresponding disk (angle &agr;). On the transversal plane, the vertical distance from the upper facet surface to the exiting nerve root at the lower/upper disk margin level (distance c/d) was also measured. Results: On the coronal plane, distance a was 16.69±5.07 mm (range, 6.60–26.10 mm), distance b was 13.64±2.52 mm (range, 9.30–21.20 mm), angle &agr; was 55.45±7.14 degrees (range, 40.00–73.00 degrees). Distance c on the transversal plane was 5.01±2.66 mm (range, 1.30–13.10 mm) and distance d was 1.99±1.26 mm (range, 0.70–7.80 mm). All these measurements increased as the spine level went down. Conclusions: The study indicated that MRN was a feasible noninvasive tool to evaluate the anatomic dimensions in the Kambin’s working zone. Before PELD, radiologic measurements of this working zone were recommended to perform a safer procedure.

Reduction in radiation during percutaneous lumbar pedicle screw placement using a new device.

Abstract Objective: To assess a new intradermal locator device for percutaneous placement of lumbar pedicle screws. Material and methods: Patients were alternately assigned to two groups. The locator group underwent lumbar pedicle screw placement using the intradermal locator. The control group was aided by traditional fluoroscopy. Baseline demographics, visual analog scale (VAS) pain scores, operation time, intraoperative fluoroscopy time and guidewire insertion time were recorded. All postoperative CT scans were reviewed by an independent spine surgeon to grade screw placement accuracy. Results: Thirty-six patients (180 screws) were assigned to the locator group and 30 patients (128 screws) to the control group. The locator device could significantly reduce the fluoroscopy time [3.9 sec (SD = 1.9) vs. 9.6 sec (SD = 5.8), p < 0.001] and guidewire insertion time [2.69 min (SD = 0.67) vs. 4.49 min (SD = 1.96), p < 0.001] compared with the conventional method for each pedicle screw. The whole operation time of the locator group was shorter than that of the control group [2-segment: 243.2 min (SD = 16.9) vs. 301.7 min (SD = 14.9), p < 0.001; 1-segment: 154.5 min (SD = 14.3) vs. 194.6 min (SD = 19.3), p < 0.001]. As for the rates of pedicle breaches, postoperative VAS scores, no significant difference was found between the two groups. Conclusion: The intradermal locator device could help reduce the radiation exposure in percutaneous pedicle screw placement while maintaining the accuracy.

Investigation of the relationship between chromobox homolog 8 and nucleus pulposus cells degeneration in rat intervertebral disc

Here, we aimed to investigate the expression of chromobox homolog 8 (CBX8) in nucleus pulposus (NP) cells from rat intervertebral disc (IVD) and its function in DNA damage and repair. NP cells were isolated from healthy rat IVD for immunohistochemistry staining. Small interfering RNA (siRNA) of CBX8 was applied for gene silencing, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to determine mRNA levels of CBX8, type II collagen, and proteoglycans. Cell proliferation and cell cycle were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony-forming assay, and flow cytometry. Hydrogen peroxide (H2O2) was added to simulate DNA oxidative damage, and expression of CBX8 was examined using RT-PCR and Western blot. After five passages, mRNA levels of type II collagen and proteoglycans decreased but that of CBX8 increased. When CBX8 was silenced by siRNA, the expressions of CBX8, type II collagen and proteoglycans declined, and the cell growth was inhibited. Besides, cell cycle was slowed down as most cells were arrest in G0/G1 phase. Furthermore, CBX8 expression went up responding to DNA oxidative damage caused by H2O2. The data indicated that CBX8 plays important roles in cell proliferation and DNA damage. Cell proliferation and cell cycle were stimulated by CBX8, which may be associated with INK4A-ARF pathway. Moreover, CBX8 plays a role in DNA damage which made it a potential gene therapy target for treatment of disc degeneration.

Direct-beam radiation exposure to surgeons during pinning of supracondylar humerus fractures.

To the Editor: We take great interest in the paper by Eismann et al1 aimed to determine how often surgeons are exposed to direct-beam radiation during pinning of supracondylar humerus fractures and whether the C-arm position and the surgeon’s experience influence radiation exposure. This double-blinded study found that direct-beam radiation exposure varied widely among surgeons, ranging from none to nearly constant exposure, but it is likely to be avoided with improved awareness about the risk of direct-beam radiation exposure and cautious surgical technique.1 However, we strongly disagree with the statement “this study’s finding is contradictory to the findings of previous studies that found exposure to be less when the C-arm was inverted.” Occupational radiation is a nonignorable issue for orthopaedic surgeon in clinical practice, but the hazards can be minimized by reduced exposure time; increased distance from the beam; increased shielding with gown, thyroid gland cover, gloves, and glasses; beam collimation; using the low-dose option; inverting the C-arm; and surgeon control of the C-arm.3 That is to say, radiation dose is not only related to the exposure time, but also the distance from the source of radiation, etc. However, we noticed the actual radiation dose in the study was not measured by the dosimeter, but the percentage of fluoroscopic films per surgery that contained the surgeon’s body. This is not convincing at all, especially when the study is trying to clarify whether the Carm position influence the radiation exposure. When the C-arm was inverted, the distance was different from the standard position. How could we determine the radiation dose by the duration of fluoroscopy exposure and the percentage of films with the body exposed, but neglect the distance? Actually, another study by Jones et al4 also found radiation exposure, measured by the dosimeter, to be less when the Carm was inverted. We really appreciate the assessment of surgeon’s hands directly exposed to the radiation beam during imaging, because, among all the exposed organs/tissues presented by International Commission on Radiological Protection, exposure of hands is found to determine the minimal operations can be performed within the occupational exposure limit under lead protection.5 However, maybe we surgeons should also realize the importance of preventing scatter radiation, because tumors are considered to exhibit a linear/linear-quadratic, no-threshold radiation relationship with stochastic effects.5

Clinical Outcome and Postoperative CT Measurements of Microendoscopic Decompression for Lumbar Spinal Stenosis.

Study Design: This was a retrospective case series. Objective: To retrospectively evaluate the clinical outcome of microendoscopic decompression for lumbar spinal stenosis (LSS) including an evaluation of the extent of decompression using computed tomography. Summary of Background Data: Microendoscopic decompression has been a widely applied procedure to treat LSS with satisfactory outcomes and comparatively fewer complications and revision. However, few reports showed computed tomography (CT) measurements of the lumbar spine to assess the postoperative decompression. Methods: This study included 103 patients (55 males and 48 females; mean age, 69 y) who underwent microendoscopic decompression for treatment of LSS between January 2009 and January 2011. All patients underwent preoperative CT and postoperative CT at 6 months and 2 years of follow-up to measure the vertebral canal area and the sagittal diameter of the lateral recess at the outer rim. The Japanese Orthopedic Association (JOA) scale, Oswestry Disability Index, and Visual Analogue Scale were used to evaluate clinical efficacy. Results: The mean vertebral canal area and sagittal diameter of the lateral recess were significantly larger at 6 months and 2 years after surgery compared with 1 day before surgery (P<0.001). The mean JOA scale scores were significantly higher at 6 and 24 months following surgery compared with before surgery (P<0.001). The mean Oswestry Disability Index scores and Visual Analogue Scale scores at 6 months and 2 years after surgery were significantly lower compared with before surgery (both P<0.001). The mean JOA recovery rates at 6 months and 2 years of follow-up were 61% and 64.3%, respectively. Conclusions: The results confirm that microendoscopic decompression for LSS is safe and effective. This study is one of the first to obtain CT measurements of the lumbar spine to assess the postoperative decompression of this procedure.

A Novel Classification and Minimally Invasive Treatment of Degenerative Lumbar Spinal Stenosis

AIM We conducted a novel classification system of degenerative lumbar spinal stenosis (DLSS) based on clinical manifestations and imaging (computed tomography and magnetic resonance imaging) features. We chose different minimally invasive surgical procedures according to our system. Clinical parameters and radiological findings will be assessed in the article. MATERIAL AND METHODS A retrospective study was conducted on 96 patients undergoing minimally invasive surgery for DLSS. We chose different surgical procedures according to our novel classification system based on clinical manifestations, imaging features, and concurrence with other spinal diseases. Clinical parameters and radiological findings were assessed pre- and postoperatively. RESULTS The mean follow up period was 24 months (range, 15~36 months). There was a statistically significant improvement in the Visual Analogue Scale (VAS) score of low back pain and leg pain after surgery (p < 0.05). According to the Japanese Orthopaedic Association (JOA) scores, the operation efficacy was excellent in 57 cases, good in 36 cases, and fair in 3 cases. According to Bridwells criterion, the fusion rate was 96% (48/50) in patients who underwent fusion surgery. There were no cages or pedicle screws related complications. CONCLUSION Minimally invasive surgical treatment of DLSS has satisfactory outcomes according to the novel classification, but further long-term, prospective, randomized controlled studies involving a larger study group are needed to validate the long-term efficacy.