Thoracolumbar fractures patients undergoing posterior pedicle screw fixation can benefit from drainage

PURPOSE

To explore whether it is necessary to put drain tubes after posterior pedicle screw fixation of thoracolumbar fractures.

METHODS

From April 2020 to January 2023, a total of 291 patients with recent thoracolumbar fractures (AO type-A or type-B) who received the pedicle screw fixation operation were enrolled retrospectively. In 77 patients, drain tubes were used in the pedicle screw fixation surgery, while no drain tubes were placed in the other group. After gleaning demographic information and results of lab examination and imageology examination, all data were put into a database. Independent-sample t-tests, Pearson Chi-Square tests, Linear regression analysis, and correlation analysis were then performed.

RESULTS

Compared to the control group, the drainage group had significantly lower postoperative CRP levels (P = 0.047), less use of antipyretics (P = 0.035), higher ADL scores (P = 0.001), and lower NRS scores (P < 0.001) on the 6th day after surgery. Other investigation items, such as demographic information, operation time, intraoperative blood loss, body temperature, and other preoperative and postoperative lab results, showed no significant differences.

CONCLUSIONS

The use of a drain tube in the pedicle screw fixation of thoracolumbar fractures is correlated with the improvement of patients' living and activity ability and the reduction of inflammation, postoperative fever and pain.

Direct vertebral rotation versus simple rod derotation techniques in correction of adolescent idiopathic scoliosis

BACKGROUND

One method for treating adolescent idiopathic scoliosis (AIS), which is characterized by abnormal spinal alignment in the coronal, sagittal, and rotational planes, is surgical correction. The two surgical techniques most typically used to correct spine alignment are simple rod derotation (SRD) and direct vertebral derotation (DVR).

AIM

The study's goal was to assess the effectiveness of two treatment methods for adolescent idiopathic scoliosis: simple rod derotation and direct vertebral rotation.

SUBJECTS AND METHODS

A randomized controlled research involving 36 adolescents with idiopathic scoliosis was done. Patients were randomly split into one of two groups: 18 patients in group A had DVR treatment, while 18 patients in group B received SRD with a 2-year follow-up.

RESULTS

Apical Vertebral Rotation measured from CT scans in DVR group was 24.4° ± 8.38° preoperatively and it decreased significantly postoperatively to 14.4° ± 4.61° with (42.22%) correction rate, while in SRD group, it was 25.03° ± 7.99° preoperatively and it also decreased significantly postoperatively to a mean value of 21.41° ± 7.01° with (14.65%) correction rate. There were statistically significant differences between both groups post-operative (P < 0.001).

CONCLUSION

The apical vertebral rotation was greatly enhanced in both procedures, with direct vertebral rotation being better. Both Simple rod derotation and direct vertebral rotation reduce the rib hump, although the improvement is much greater with direct vertebral rotation.

A Propensity Score-Matched Cohort Study Comparing 3 Different Spine Pedicle Screw Fixation Methods: Freehand, Fluoroscopy-Guided, and Robot-Assisted Techniques

OBJECTIVE

This study aimed to compare the accuracy of robotic spine surgery and conventional pedicle screw fixation in lumbar degenerative disease. We evaluated clinical and radiological outcomes to demonstrate the noninferiority of robotic surgery.

METHODS

This study employed propensity score matching and included 3 groups: robot-assisted mini-open posterior lumbar interbody fusion (PLIF) (robotic surgery, RS), c-arm guided minimally invasive surgery transforaminal lumbar interbody fusion (C-arm guidance, CG), and freehand open PLIF (free of guidance, FG) (54 patients each). The mean follow-up period was 2.2 years. The preoperative spine condition was considered. Accuracy was evaluated using the Gertzbein-Robbins scale (GRS score) and Babu classification (Babu score). Radiological outcomes included adjacent segmental disease (ASD) and mechanical failure. Clinical outcomes were assessed based on the visual analogue scale, Oswestry Disability Index, 36-item Short Form health survey, and clinical ASD rate.

RESULTS

Accuracy was higher in the RS group (p < 0.01) than in other groups. The GRS score was lower in the CG group, whereas the Babu score was lower in the FG group compared with the RS group. No significant differences were observed in radiological and clinical outcomes among the 3 groups. Regression analysis identified preoperative facet degeneration, GRS and Babu scores as significant variables for radiological and clinical ASD. Mechanical failure was influenced by the GRS score and patients' age.

CONCLUSION

This study showed the superior accuracy of robotic spine surgery compared with conventional techniques. When combined with minimally invasive surgery, robotic surgery is advantageous with reduced ligament and muscle damage associated with traditional open procedures.

Pedicle Screw Fixation With Cement Augmentation Versus Without in the Treatment of Spinal Stenosis Following Posterior Spinal Fusion Surgery, Superiority According to Bone Mineral Density: A Three-Arm Randomized Clinical Trial

OBJECTIVE

To investigate whether cement augmentation has an impact on clinical and radiologic outcomes following posterior spinal fusion (PSF) in low-density bones and whether its performance is comparable to regular bone density.

METHODS

Between 2017 and 2021, 114 patients with spinal canal stenosis were enrolled to undergo PSF. They were initially stratified based on their bone mineral density: T-score ≥ -1.5: Group I (n = 34), and T-score < -1.5: Group II (n = 80). Furthermore, group II was randomly subdivided: II-A (unaugmented, n = 35) and II-B (bone cement augmented, n = 45). The primary and secondary endpoints of the study were evaluated using visual analog scales (VAS) and radiologic parameters, including screw loosening, screw or rod fractures, proximal junctional kyphosis (PJK), proximal junctional vertebral fracture (PJVF), and adjacent segment disease (ASD), at 1 year postoperatively.

RESULTS

All 3 groups showed improvement in VAS scores, but the most significant improvements were seen in groups I and II-B. Group II-B had lower incidence rates of ASD, PJVF, PJK, rod, and screw fracture compared to group II-A, but only screw loosening was statistically significant (P < 0.0001). Contrary, there were statistically significant differences in all variables except for ASD and screw fracture (P = 0.0576 and 0.670, respectively) when comparing groups I and II-A. In both groups I and II-A, screw loosening was the most common complication following PSF, while only 5.41% of patients in group II-B experienced it.

CONCLUSIONS

The efficacy of cement augmentation in mitigating pain and screw loosening following PSF surgery in low-density bones is comparable to that of normal-density bone.

3D printed pedicle screw guides reduce the rate of intraoperative screw revision in adolescent idiopathic scoliosis surgery

BACKGROUND CONTEXT

Pedicle screw fixation has become common in the treatment of adolescent idiopathic scoliosis (AIS). Malpositioned pedicle screws have significant complications and identifying surgical techniques to optimize screw placement accuracy is imperative.

PURPOSE

To compare the rate of intraoperative revision, replacement, or removal of pedicle screws placed utilizing 3D printed guides compared with pedicle screws placed utilizing a freehand technique.

STUDY DESIGN/SETTING

Retrospective cohort study/single academic center.

PATIENT SAMPLE

Thirty-two patients aged 10 to 18 with AIS.

OUTCOME MEASURES

Revision rate of pedicle screws and operative time between groups.

METHODS

A retrospective study was performed on patients 10 to 18 years of age who underwent posterior spinal instrumented fusion for AIS from February 2021 to July 2022. The study received an IRB exemption. Patient demographics, intraoperative measures, and outcome variables were recorded. Intraoperatively, all patients underwent a 3-dimensional fluoroscopic "check scan," which included axial, sagittal, and coronal images, to assess for screw accuracy. A secondary outcome of operative time was compared between groups. The p-values <.05 were considered significant.

RESULTS

A total of 32 patients were included in this study. There were 17 cases in the 3D guided and 15 cases in fluoroscopy-guided freehand cohort. There was a total of 254 pedicle screws using 3D guides and 402 screws using freehand technique. Between cohorts, there were no significant differences in a number of levels fused (p=.54) or length of surgery (p=.36). The total revision rate of 3D guided screw placement was 5.5% and that of the freehand technique was 8.5%. The freehand screw placement group had significantly higher revision rates per vertebral level compared with 3D guided (p=.0096). Notably, 3D printed guides had fewer screws that were removed/revised for being too anterior (7.1%) compared with freehand (23.5%). Surgical time was not significantly different between the 3D guided and freehand cohort (p=.35).

CONCLUSIONS

3D printed guides reduce intraoperative revision rate compared with freehand techniques. Total operative time is comparable to freehand technique.

Recent Efficacy of Oblique Lateral Interbody Fusion Combined With Wiltse Approach Pedicle Screw Fixation for Degenerative Single-Level Lumbar Spondylolisthesis

BACKGROUND

The study aimed to explore the recent efficacy of oblique lateral interbody fusion (OLIF) combined with Wiltse approach pedicle screw fixation in the treatment of single-level degenerative lumbar spondylolisthesis (DLS).

METHODS

This is a retrospective study. The study enrolled 54 patients with single-level DLS who were treated at the Affiliated Jiangnan Hospital of Zhejiang Chinese Medical University from May 2018 to June 2020. (OLIF group) 24 cases operated using OLIF combined with Wiltse approach pedicle screw fixation, and (PLIF group) 30 cases operated by PLIF. The primary outcome measures were visual analog scale (VAS) pain scores, Oswestry dysfunction index (ODI), and the lower lumbar spine anterior convexity angle.

RESULTS

There were significant differences in VAS (2.63 ± 0.58 vs. 3.57 ± 0.63, P < 0.001) and ODI (9.67 ± 0.92 vs. 10.63 ± 1.40, P < 0.05) between the OLIF group and PLIF group on postoperative 3 days. And there was a significant decrease in VAS (2.63 ± 0.58 vs. 1.08 ± 0.28, P < 0.05) and ODI (3.57 ± 0.63 vs. 1.10 ± 0.31, P < 0.05) in both groups on postoperative 3 days and at 6 months postoperative comparisons. OLIF group showed better intervertebral space height and the lower lumbar spine anterior convexity angle scores on postoperative 3 days and 6 months, the difference was statistically significant(all P < 0.05).

CONCLUSIONS

OLIF combined with the Wiltse approach pedicle screw fixation can achieve good short-term clinical results in the treatment of single-level DLS. This surgical approach is less invasive, promotes early functional recovery, shortens hospitalization time, and improves the quality of life.

Development of a Pedicle Screw Fixation Simulation Model for Surgical Training Using a 3-Dimensional Printer

OBJECTIVE

Training surgeons in pedicle screw fixation (PSF) techniques during actual surgery is limited because of patient safety, complications, and surgical efficiency issues. Recent technical developments are leading the world to an era of personalized three-dimensional (3D) printing. This study aimed to evaluate the educational effect of using a 3D-printed spine model to train beginners in PSF techniques to improve screw accuracy and procedure time.

METHODS

Computed tomography (CT) scan data were used in a 3D printer to produce a life-size lumbar spine replica of L1-3 vertebrae. Four residents performed PSF thrice. Each resident performed 18 screw fixations on both sides (6 screws per trial). The time to complete the procedure and pedicle violation was recorded.

RESULTS

The average time for the 3 procedures was 42.1±2.9 minutes, 38.8±3.3 minutes, and 32.1±2.5 minutes, respectively. Furthermore, the average pedicle screw score for the 3 procedures was 13.0±0.8, 14.5±0.6, and 16.0±0.8, respectively. As the trial was repeated, the procedure time decreased and the accuracy of screw fixation tended to be more accurate.

CONCLUSIONS

It was possible to decrease the procedure time and increase accuracy through repeated training using the 3D-printed spine model. By implementing a 3Dprinted spine model based on the patient's actual CT data, surgeons can perform simulation surgery before the actual surgery. Therefore, this technology can be useful in educating residents to improve their surgical skills.

Comparison of three techniques in the surgical management of metastatic vertebral fracture with posterior wall damage: a retrospective study

BACKGROUND

To retrospectively compare the safety and efficacy of percutaneous kyphoplasty (PKP), internal fixation (IF), and kyphoplasty combined with internal fixation (KP + IF) in treating metastatic vertebral fracture (MVF) with posterior wall damage.

METHODS

87 patients with MVF with posterior wall damage underwent surgery. In Group PKP, 36 patients underwent PKP; in Group IF, 20 patients underwent pedicle screw fixation; and in Group KP + IF, 31 patients underwent kyphoplasty combined with pedicle screw fixation. Operative time, intraoperative blood loss, clinical and radiological results, and complication rate in each group were evaluated and compared.

RESULTS

Significant improvement on the VAS, ODI scores, vertebral height and local kyphotic angle (LKA) was noted in each group (P < 0.001). Group PKP and Group KP + IF achieved better pain relief than Group IF (P < 0.05). At postoperative 3 days, Group PKP had better pain relief than Group KP + IF (P < 0.05). At other follow-up time points, there were no differences between Group PKP and KP + IF (P > 0.05). Group KP + IF and Group IF were more efficacious than Group PKP in terms of height restoration and LKA correction (P < 0.05). Group KP + IF had a higher incidence of postoperative complications than Group PKP and Group IF(P < 0.05).

CONCLUSIONS

PKP was safe and effective in treating MVF with posterior wall damage. It can achieve similar clinical outcomes compared to KP + IF, but associated with less operative time, less blood loss and fewer complications. IF alone should not be the first treatment option for its poorer analgesic effect.

Is unilateral pedicle screw fixation as effective as bilateral pedicle screw fixation in transforaminal lumbar interbody fusion: a meta-analysis of randomized controlled trials

PURPOSE

This meta-analysis aimed to investigate whether unilateral pedicle screw fixation (UPSF) is comparable to bilateral pedicle screw fixation (BPSF) in transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

METHODS

Up to September 2022, established electronic literature databases including PubMed, Web of Science, EMBASE, and the Cochrane Library were systematically searched. Randomized controlled trials (RCTs) published in English that compared the efficacy of UPSF versus BPSF in TLIF were included. The methodological quality was evaluated, relevant data was extracted, and suitable meta-analysis was carried out. Data of fusion rate, complications, cage migration, visual analog scale (VAS), and Oswestry Disability Index (ODI), total blood loss (TBL), operation time, and hospital stay were extracted and analyzed. Pooled mean differences and risk ratio (RR) along with 95% confidence intervals (95% CI) were calculated for the results.

RESULTS

Ten RCTs including 614 patients (UPSF = 294, BPSF = 320) were included in our meta-analysis. There were no significant differences in terms of fusion rate, VAS (VAS-BP and VAS-LP), ODI, complications, or hospital stay between UPSF and BPSF groups (P > 0.05, respectively). The UPSF group clearly had the advantage of less blood loss (SMD = -2.99, 95% CI [-4.54, -1.45], P = 0.0001) and operation time (SMD = -2.05, 95% CI [-3.10, -1.00], P = 0.0001). However, UPSF increased cage migration more than BPSF (10.7% vs 4.8%, RR = 2.23, 95% CI [1.07, 4.65],  P = 0.03).

CONCLUSION

According to the findings of this meta-analysis, UPSF is just as effective as BPSF in TLIF and may reduce blood loss and operation time. Nevertheless, UPSF may result in more cage migration than BPSF.

[Intraoperative computed tomography-guided navigation for implant anchorage in spine surgery]

OBJECTIVE

Improved accuracy of spinal instrumentation with the use of intraoperative CT (iCT).

INDICATIONS

All types of posterior spinal instrumentation.

CONTRAINDICATIONS

None.

SURGICAL TECHNIQUE

After fixation of the spinal clamp, an intraoperative CT (iCT) is performed. The image data set can then be used for navigation of the spinal implants. The arrangement of the devices, positioning of the patient, and the exact fixation of the clamp depend on the operation technique and the anatomical region. A high level of standardization is necessary for clinical success. In general, the utilization of drill guides over the use of awls and Yamshidi needles is strongly recommended. Thereby the risk of segmental vertebral rotation, especially in multisegmental instrumentation, will be reduced.

POSTOPERATIVE MANAGEMENT

The postoperative management depends on the type of surgery and is not influenced by the use of navigation with iCT.

RESULTS

In our patient group of the first 200 surgeries with iCT (AIRO, Brainlab AG, Munich, Germany), we performed 34% cervical instrumentations, 31% percutaneous screw insertions, and 35% multisegmental open procedures including the sacrum or ilium. Two surgeries had to be converted to conventional technique due to technical problems. One misplaced S2/Ala/ilium screw had to be corrected in revision surgery. The infection rate was 2.5% and was not increased compared to conventional procedures. In the literature, a significant reduction of radiation exposure was shown, when iCT and navigation were used. Also, in longer surgical cases the operation time could be reduced. In comparison with 3D C‑arm imaging, the image quality and screw accuracy is improved by iCT. Due to the possibility of 3D intraoperative implant control, the number of revision cases can be reduced.

Modified pedicle screw fixation under guidance of stress analysis for cervicothoracic junction: Surgical technique and outcomes

BACKGROUND

In cervicothoracic junction, the use of strong fixation device such as pedicle screw placement is often needed.

OBJECTIVE

The current study aimed to evaluate the accuracy and safety of pedicle screw placement using stress conduction analysis in the clinical application.

METHODS

We retrospectively collected patients who underwent pedicle screw internal fixation in cervicothoracic junction. Patients were divided into conventional nail placement (Group A) and modified pedicle screw implantation under guidance of stress analysis (Group B) according to the methods of pedicle screw placement. The accuracy of pedicle screw placement was assessed by computed tomography (CT) examination, and the success rate was calculated.

RESULTS

A total of 80 patients who underwent pedicle screw internal fixation in cervicothoracic junction were included. There were no obvious differences in baseline characteristics between two groups. The success rate of total screw placement, cervical spine screw placement and upper thoracic spine screw placement in Group B was higher than those in Group A (P< 0.001, P= 0.005, P= 0.008). Additionally, Heary Grade I in the Group B was higher than Group A (P= 0.001).

CONCLUSION

Stress analysis-guided technique can increase the accuracy of pedicle screw placement. Importantly, it meets the requirements of internal fixation of the cervicothoracic junction.

Pedicle screw fixation combined with posterior decompression and bone grafting for thoracolumbar spinal fractures can enhance curative effect and spinal cord function

OBJECTIVE

To explore the efficacy of pedicle screw fixation (PSF) combined with posterior decompression and bone grafting for thoracolumbar spinal fractures (TLSFs) and its influence on spinal cord function.

METHODS

In this retrospective study, 94 patients with TLSFs treated in the China-Japan Friendship Hospital rom June 2015 and September 2020 were selected, including 53 cases in the joint group treated with PSF combined with posterior decompression and bone grafting, and 41 cases in the control group with PSF alone. The two groups were compared in terms of operation time, intra-operational blood loss, length of hospital stay and wound healing as well as the pre- and post-treatment spinal cord function, and patients' clinical outcomes. Pre- and post-operatively, the pain severity was evaluated by the Visual Analogue Scale (VAS), the spinal dysfunction was assessed by Oswestry Disability Index (ODI), and the injured vertebral height and Cobb angles of the thoracolumbar spine (TLS) were compared. The clinical efficacy and postoperative complication rates of the two groups were observed and compared.

RESULTS

Less operative time, intraoperative bleeding, hospitalization time and wound healing time were determined in the joint group compared with the control group (all P<0.05). The postoperative sensory function and motor function were also better in the joint group (all P<0.05). Postoperatively, the joint group showed lower VAS and ODI scores than in the control group, with lower upper and lower TLS Cobb angles, and higher height of the anterior and posterior margins of the fractured vertebra (all P<0.05). The total effective rate was higher, and the incidence of postoperative complications was significantly lower in the joint group compared with the control group.

CONCLUSION

PSF combined with posterior decompression and bone grafting is effective in the treatment of TLSFs, which can not only significantly improve the spinal cord function and alleviate spinal dysfunction, but also help to relieve pain and reduce postoperative complications.

Study on the Optimal Surgical Scheme for Very Severe Osteoporotic Vertebral Compression Fractures

OBJECTIVE

Therapy of very severe osteoporotic compression fractures (VSOVCF) has been a growing challenge for spine surgeons. Opinions vary regarding the optimal surgical procedure for the treatment of VSOVCF and which internal fixation method is more effective is still under debate, and research on this topic is lacking. This retrospective study was conducted to compare the efficacy and safety of various pedicle screw fixation methods for treating VSOVCF.

METHODS

This single-center retrospective comparative study was conducted between January 2015 and September 2020. Two hundred and one patients were divided into six groups according to different surgical methods: 45 patients underwent long-segment fixation (Group 1); 39 underwent short-segment fixation (Group 2); 30 received long-segment fixation with cement-reinforced screws (Group 3); 32 received short-segment fixation with cement-reinforced screws (Group 4); 29 had long-segment fixation combined with kyphoplasty (PKP) (Group 5); and 26 cases had short-segment fixation combined with PKP (Group 6). The clinical records were reviewed and the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) score were used for clinical evaluation. The vertebral height (VH), fractured vertebral body height (FVBH), and Cobb's angle were objectively calculated and analyzed on lateral plain radiographs. Student's t-tests and one-way ANOVA among groups were conducted to analyze the continuous, and the chi-squared test was used to compare the dichotomous or categorical variables. The difference was considered statistically significant when the P-value was less than 0.05.

RESULTS

The six groups had similar distributions in age, gender, course of the disease, follow-up period, and injured level. In the postoperative assessment of the VAS score, the surgical intervention most likely to rank first in terms of pain relief was the short-segment fixation with cement-reinforced screws (Group 4). For the functional evaluation, the surgical intervention that is most likely to rank first in terms of ODI score was a short-segment fixation with cement-reinforced screws (Group 4), followed by long-segment fixation (Group 1). The long-segment fixation with cement-reinforced screws was the first-ranked surgical intervention for the maintenance of Cobb's angle and vertebral height, whereas the short-segment fixation performed the worst. The highest overall complication rate was in Group 6 with an incidence of 42.3% (11/26), followed by Group 2 with an incidence of 38.5% (15/39).

CONCLUSION

For the treatment of VSOVCF, the short-segment fixation with cement-reinforced screws is the most effective and optimal procedure, and should be used as the preferred surgical method if surgeons are proficient in using cemented screws; otherwise, directly and unquestionably use long-segment fixation to achieve satisfactory clinical results.

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.

Biomechanical Evaluation of Transforaminal Lumbar Interbody Fusion with Coflex-F and Pedicle Screw Fixation: Finite Element Analysis of Static and Vibration Conditions

OBJECTIVE

To investigate the biomechanics of transforaminal lumbar interbody fusion (TLIF) with interspinous process device (IPD) or pedicle screw fixation under both static and vibration conditions by the finite element (FE) method.

METHOD

A validated FE model of the L1-5 lumbar spine was used in this study. This FE model derived from computed tomography images of a healthy female adult volunteer of appropriate age. Then the model was modified to simulate L3-4 TLIF. Four conditions were compared: (i) intact; (ii) TLIF combined with bilateral pedicle screw fixation (BPSF); (iii) TLIF combined with U-shaped IPD Coflex-F (CF); and (iv) TLIF combined with unilateral pedicle screw fixation (UPSF). The intact and surgical FE models were analyzed under static and vibration loading conditions respectively. For static loading conditions, four motion modes (flexion, extension, lateral bending, and axial rotation) were simulated. For vibration loading conditions, the dynamic responses of lumbar spine under sinusoidal vertical load were simulated.

RESULT

Under static loading conditions, compared with intact case, BPSF decreased range of motion (ROM) by 92%, 95%, 89% and 92% in flexion, extension, lateral bending and axial rotation, respectively. While CF decreased ROM by 87%, 90%, 69% and 80%, and UPSF decreased ROM by 84%, 89%, 66% and 82%, respectively. Compared with CF, UPSF increased the endplate stress by 5%-8% in flexion, 7%-10% in extension, 2%-4% in lateral bending, and decreased the endplate stress by 16%-19% in axial rotation. Compared with CF, UPSF increased the cage stress by 9% in flexion, 10% in extension, and decreased the cage stress by 3% in lateral bending, and 13% in axial rotation. BPSF decreased the stress responses of endplates and cage compared with CF and UPSF. Compared BPSF, CF decreased the facet joint force (FJF) by 6%-13%, and UPSF decreased the FJF by 4%-12%. During vibration loading conditions, compared with BPSF, CF reduced maximum values of the FJF by 16%-32%, and vibration amplitudes by 22%-35%, while UPSF reduced maximum values by 20%-40%, and vibration amplitudes by 31%-45%.

CONCLUSION

Compared with other surgical models, BPSF increased the stability of lumbar spine, and also showed advantages in cage stress and endplate stress. CF showed advantages in IDP and FJF especially during vertical vibration, which may lead to lower risk of adjacent segment degeneration. CF may be an effective alternative to pedicle screw fixation in TLIF procedures.

Bone Cement and Pedicle Screw for the Treatment of Spinal Tumors with Spinal Cord Compression and Posterior Wall Defects

OBJECTIVE

To compare the safety and efficacy of posterior internal fixation with open vertebroplasty (VP) and posterior internal fixation with open kyphoplasty (KP) in the treatment of metastatic epidural spinal cord compression (MESCC) with posterior wall destruction.

METHODS

This retrospective study, conducted between January 2016 and May 2019, equally divided 60 patients with MESCC and posterior wall destruction into two groups based on the surgical method: open vertebroplasty with pedicle screw fixation (VP group) and open kyphoplasty with pedicle screw fixation (KP group). Visual analogue scale (VAS), SF-36 scores, middle vertebral height (MVH), and posterior vertebral height (PVH) were evaluated for the two groups preoperatively, postoperatively, and 1 year after surgery. Spinal Instability Neoplastic Score, Frankel grades and complications were recorded and evaluated.

RESULTS

Five patients were excluded from the analysis, and our study cohort consisted of 55 adult patients who met the inclusion criteria. The VAS and SF-36 scores of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). There were significant differences in total cost (8835 ± 1468 vs 9540 ± 053 USD) and cement volume (4.51 ± 0.96 ml vs 6.35 ± 1.09 ml) between two groups (P < 0.05). The MVH and PVH of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). The MVH was significantly larger in the KP group than in the VP group postoperatively (20.15 ± 4.86 vs 17.70 ± 3.78, P < 0.05) and at the final follow-up (20.42 ± 5.59 vs 17.28 ± 3.23, P < 0.05). However, the PVH of the two groups did not significantly differ at the two postoperative follow-ups (P > 0.05). No significant differences were found in surgery time, time from surgery to discharge, blood loss and complications between both groups postoperatively (P > 0.05).

CONCLUSION

In the short term, both approaches are effective and safe in patients with MESCC and posterior wall destruction. The posterior internal fixation with open VP may be a good choice of surgical method in patients with MESCC and posterior wall defects.

The Mini-Open Wiltse Approach with Pedicle Screw Fixation Versus Percutaneous Pedicle Screw Fixation for Treatment of Neurologically Intact Thoracolumbar Fractures: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of the present study was to compare the clinical outcomes and complications between the mini-open Wiltse approach with pedicle screw fixation (MWPSF) and percutaneous pedicle screw fixation (PPSF) in treating neurologically intact thoracolumbar fractures.

METHODS

We comprehensively searched PubMed, Web of Science, Embase, and the Cochrane Library and performed a systematic review and meta-analysis of all randomized controlled trials and retrospective comparative studies assessing these important indexes of the 2 methods using Review Manager, version 5.4. The clinical outcomes are presented as the risk difference for dichotomous outcomes and the mean difference for continuous outcomes with the 95% confidence intervals. Heterogeneity was assessed using the χ² test and I² statistics. The study was registered with PROSPERO (CRD 42021290078).

RESULTS

Two randomized controlled trials and six retrospective cohort studies were included in the present analysis. The percutaneous approach was associated with less intraoperative blood loss compared with the mini-open Wiltse approach. No significant differences were found in the total length of the incisions, hospitalization time, postoperative visual analog scale scores, postoperative Oswestry disability index, postoperative Cobb angle, postoperative Cobb angle correction, postoperative Cobb angle correction loss, accuracy rate of pedicle screw placement, and postoperative complications between MWPSF and PPSF. However, the incidence of facet joint violation was significantly higher in the PPSF group. In addition, MWPSF was associated with a shorter operative time, shorter intraoperative fluoroscopy time, lower hospitalization costs, better postoperative vertebral body angle and percentage of vertebral body height compared with PPSF.

CONCLUSIONS

Both MWPSF and PPSF are safe and effective treatments of neurologically intact thoracolumbar fractures. Nevertheless, our results have indicated that MWPSF might be the better choice, because it has a shorter learning curve and decreased facet joint violation, operative time, hospitalization costs, and radiation exposure. In addition, MWPSF was associated with better improvement of the postoperative vertebral body angle and percentage of vertebral body height.

Risk factor analysis of disc and facet joint degeneration after intersegmental pedicle screw fixation for lumbar spondylolysis

Background

Patients who do not respond to conservative treatment of the isthmus are often treated with surgery. We used direct repair plus intersegment pedicle screw fixation for the treatment of lumbar spondylolysis. The aim of this observational study was to assess the effects of this technique and evaluate various risk factors potentially predicting the probability of disc and facet joint degeneration after instrumentation.

Methods

The study included 54 male L5 spondylolysis patients who underwent pars repair and intersegment fixation using pedicle screws. Bony union was evaluated using reconstruction images of computed tomography. Radiographic changes, including disc height, vertebral slip, facet joint and disc degeneration in the grade of adjacent and fixed segments, were determined from before to final follow-up. Logistic regression analysis was performed to identify factors associated with the incidence of disc and facet joint degeneration.

Results

Bony union was achieved in all cases. Logistic regression analysis revealed that instrumentation durations of greater than 15.5 months and 21.0 months were significant risk factors for the incidence of L4/5 and L5S1 facet degeneration, respectively.

Conclusions

Intersegmental pedicle screw fixation provides good surgical outcomes and good isthmic bony union rates in patients with lumbar spondylolysis. The duration of fixation was confirmed as a risk factor for facet joint degeneration. Once bony union is achieved, instrument removal should be recommended.

One-stage freehand minimally invasive pedicle screw fixation combined with mini-access surgery through OLIF approach for the treatment of lumbar tuberculosis

Objective

To compare one-stage freehand minimally invasive pedicle screw fixation (freehand MIPS) combined with mini-access surgery through OLIF approach with posterior approach for treatment of lumbar tuberculosis (TB), and evaluate its feasibility, efficacy and safety in debridement, bone graft fusion and internal fixation.

Methods

48 patients with single segment lumbar TB from June 2014 to June 2017 were included. Among them, 22 patients underwent one-stage freehand MIPS combined with mini-access surgery through OLIF approach (group 1), 26 patients were treated with posterior open surgery (group 2). Duration of operation, blood loss, and stay time in hospital were compared. Pre- and postoperative visual analog scale (VAS) pain scores, Oswestry disability index (ODI), erythrocyte sedimentation rate, complications and images were also recorded.

Results

Patients in group 1 showed significantly less blood loss (165 ± 73 ml vs 873 ± 318 ml, P < 0.001), shorter stay time in hospital (6/4–8 days vs 12/8–15 days, P < 0.001), while longer duration of operation (185 ± 14 min vs 171 ± 12 min, P < 0.001) than group 2 did. VAS scores significantly decreased after surgery in both groups, however, VAS scores of group 1 were significantly lower than that of group 2 immediately after surgery and during follow-ups (P < 0.001). ODI of group 1 was also significantly lower than that of group 2 at 12-month after surgery (P < 0.001).

Conclusion

One-stage freehand MIPS combined with mini-access surgery through OLIF approach is a feasible, efficient and safe method in treating single segment lumbar TB. It shows advantages of less surgical trauma and faster postoperative recovery.

Occurrence of adjacent segment fractures after surgical treatment of an osteoporotic vertebral fracture: a retrospective comparison between two different treatment methods

INTRODUCTION

Osteoporotic vertebral fractures are a major healthcare problem. Vertebral cement augmentation (VCA) is frequently used as a minimally invasive surgical approach to manage symptomatic fractures. However, there is a potential risk of adjacent segment fracture (ASF), which may require second surgery. The addition of transcutaneous screw-fixation with cement augmentation superior and inferior to the fracture [Hybrid transcutaneous screw fixation (HTSF)] might represent an alternative treatment option to reduce the incidence of ASF.

MATERIALS AND METHODS

We retrospectively compared surgery time, hospital stay, intraoperative complication rate and the occurrence of ASF with the need for a surgical treatment in a cohort of 165 consecutive patients receiving either VCA or HTSF in our academic neurosurgical department from 2012 to 2020. The median follow-up was 52.3 weeks in the VCA-group and 51.9 in the HTSF-group.

RESULTS

During the study period, 93 patients underwent VCA, and 72 had HTSF. Of all patients, 113 were females (64 VCA; 49 HTSF) and 52 were males (29 VCA; 23 HTSF). The median age was 77 years in both groups. Median surgery time was 32 min in the VCA-group and 81 min in the HTSF-group (p < 0.0001). No surgery-related complications occurred in the VCA-group with two in the HTSF-group (p = 0.19). ASF was significantly higher in the VCA-group compared to HTSF (24 [26%] vs. 8 [11%] patients; p < 0.02). The proportion of patients requiring additional surgery due to ASF was higher in the VCA-group (13 vs. 6%), but this difference was not statistically significant (p = 0.18). Median hospital stay was 9 days in the VCA-group and 11.5 days in the HTSF-group (p = 0.0001).

CONCLUSIONS

Based on this single-center cohort study, HTSF appears to be a safe and effective option for the treatment of osteoporotic vertebral compression fractures. Surgical time and duration of hospital stay were longer in the HTSF-group, but the rate of ASF was significantly reduced with this approach. Further studies are required to ascertain whether HTSF results in superior long-term outcomes or improved quality of life.

Biomechanical Evaluation and Preliminary Clinical Results of Anterolateral Screw Fixation for Oblique Lumbar Interbody Fusion Surgery

BACKGROUND

The most common complication of oblique lumbar interbody fusion (OLIF) is endplate fracture/subsidence. The aim of this study was to evaluate biomechanical stability in patients undergoing OLIF surgery with anterolateral screw fixation (ASF).

METHODS

Based on a previously validated model technique, L4-L5 functional surgical models corresponding to the ASF and bilateral pedicle screw fixation (BPSF) methods were created. Finite element models were developed to compare the biomechanics of the ASF and BPSF groups. We retrospectively analyzed 18 patients with lumbar degenerative diseases who underwent OLIF with ASF in Shenzhen Hospital of Southern Medical University from April 2020 to April 2021. Intraoperative and postoperative complications were observed.

RESULTS

Compared with the BPSF model, the maximum stresses of the L4 inferior endplate and L5 superior endplate were greatly increased in the ASF model. The contact surface between the vertebrae and screw (CSVS) in the ASF model produced nearly 100% more stress than the BPSF model at all moments. In clinical practice, after a 12-month follow-up, 7 adverse events were observed, including 3 cases of left thigh pain/numbness, 3 cases of cage subsidence, and 1 case of screw loosening.

CONCLUSIONS

OLIF surgery with ASF could not reduce the maximum stresses on the endplate and CSVS, which may be a potential risk factor for cage subsidence and screw loosening.

Effect of percutaneous minimally invasive pedicle screw internal fixation in the treatment of thoracolumbar vertebral fractures and its impact on quality of life

Objectives

To investigate and analyze the effect of percutaneous minimally invasive pedicle screw internal fixation in the treatment of thoracolumbar vertebral fractures and its impact on quality of life.

Methods

Fifty patients with thoracolumbar vertebral fracture admitted to our hospital from January 2015 to December 2018 were selected and divided into two groups according to different treatment regimens. The observation group was treated with minimally invasive percutaneous pedicle screw internal fixation, while the control group was treated with traditional posterior approach open pedicle screw internal fixation. The surgery time, incision length, intraoperative blood loss, postoperative drainage, hospitalization time, ambulation time, fracture healing time and postoperative VAS scores were compared between the two groups. In addition, the cobb angle, the sagittal plane index, and the anterior vertebral height were compared between the two groups before and after surgery, as were the Oswestry Disability Index (ODI) at 1d, 3 months, and 6 months postoperatively.

Results

The surgery time, incision length, postoperative pain level, postoperative drainage and intraoperative blood loss of the observation group were less than those of the control group (P<0.05). The postoperative Cobb angle of the two groups decreased, the sagittal plane index as well as the anterior vertebral height increased (P<0.05). The Oswestry index of the observation group was better than that of the control group at one day and three months postoperatively, with a statistical significance between the two groups (P<0.05). The complication rate of the observation group was significantly lower than that of the control group (P<0.05).

Conclusion

Percutaneous minimally invasive pedicle screw internal fixation is safer than the traditional open pedicle screw internal fixation, and it is more worthy of clinical promotion.

Surgical outcomes in children under 10 years old in the treatment of congenital scoliosis due to single nonincarcerated thoracolumbar hemivertebra: according to the age at surgery

Purpose

Hemivertebra is one of the common pathogenesis of congenital scoliosis. The timing of operation is undefined. Our study compared the surgical outcomes in children under age 10 years with scoliosis due to single nonincarcerated thoracolumbar hemivertebra according to the age at surgery.

Methods

From January 2009 to August 2017, we retrospectively investigated 34 consecutive cases of congenital scoliosis treated by posterior hemivertebra resection and fusion with pedicle screw fixation. All cases were divided into two groups according to the age at surgery and followed-up for at least 2 years, group 1 (≤ 5 years old), and group 2 (5 to 10 years old).

Results

The mean Cobb angle of the main curve was improved from 48.58° to 15.53° (68.05%) in group 1, and from 43.73° to 11.33° (75.43%) in group 2. The segmental curve was improved from 44.16° to 11.53° (74.64%) in group 1, and the segmental curve was consistent with the main curve in group 2. The mean segmental kyphosis was improved from 27.50° to 8.42° (67.40%) in group 1, and from 29.00° to 5.00° (84.73%) in group 2. Five patients developed distal adding-on, and four patients were found proximal junctional kyphosis during the follow-up.

Conclusion

Not all the deformities caused by single nonincarcerated thoracolumbar hemivertebra would progress greatly with the spinal growth. No significant statistical differences were found in the coronal and sagittal correction rate between the two groups. A limited delayed surgery after 5 years but before 10 years of age with close follow-up can achieve satisfied results.

The effect of cement augmentation on pedicle screw fixation under various load cases : results from a combined experimental, micro-CT, and micro-finite element analysis

Aims

Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques.

Methods

Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S⁴). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads.

Results

Experimental pull-out strengths were excellently correlated to the µFE pull-out stiffness of the ROI (R² > 0.87) and FV (R² > 0.84) models. No significant difference due to screw design was observed. Cement augmentation increased pull-out stiffness by up to 94% and 48% for L and R screws, respectively, but only increased bending stiffness by up to 6.9% and 1.5%, respectively. Cementing involving only one screw tip resulted in lower stiffness increases in all tested screw designs and loading cases. The stiffening effect of cement augmentation on pull-out and bending stiffness was strongly and negatively correlated to local bone density around the screw (correlation coefficient (R) = -0.95).

Conclusion

This combined experimental, µCT and µFE study showed that regional analyses may be sufficient to predict fixation strength in pull-out and that full analyses could show that cement augmentation around pedicle screws increased fixation stiffness in both pull-out and bending, especially for low-density bone.

Cite this article: Bone Joint Res 2021;10(12):797–806.

Caudad Insertion of Pedicle Screws Facilitates Interbody Distraction During Spondylolisthetic Vertebrae Restoration: A Retrospective Study

INTRODUCTION

Based on the results of long-term clinical and radiological follow-up studies of decompression and fusion with internal fixation for degenerative lumbar spondylolisthesis (DLS), we recognized that the direction of the pedicle screw affects the stability of the fixation. However, few studies have analyzed the role of pedicle screw insertion trajectory in disc height recovery after fusion. We therefore analyzed patients' general information, clinical efficacy and sagittal, coronal and implant parameters to determine whether there is a correlation between the insertion trajectory of screws and the recovery of intervertebral space height, with the ultimate aim to provide a basis for improving the clinical efficacy and radiological outcomes of patients with DLS and to identify an optimal technique for spine surgeons that would benefit patients with spondylolisthesis.

METHODS

From May 2015 to October 2019, patients who underwent single-segment decompression and fusion with internal fixation for DLS at our department were screened for enrollment in the study. The clinical history, pre- and post-operative lumbar sagittal parameters, intervertebral height, rate of recovery from spondylolisthesis and pedicle screw angle of inpatients were recorded and followed up for at least 6 months. Clinical assessments included the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for lower back and leg pain. Data on screw angle, fusion segment intervertebral space height and clinical outcome were the primary outputs. Pearson correlation and multivariate regression analyses were performed to investigate the relationship between the pedicle screw angle, the sagittal parameters of the fusion segment and clinical efficacy.

RESULTS

A total of 50 patients were initially enrolled, two patients were lost to follow-up after 6 months, 48 patients (17 men, 31 women) were eventually enrolled, and the follow-up rate was 96%. At least 6 months after the operation, vertebral spondylolisthesis improved to varying degrees [> 80% in 17 cases (35.4%) and > 20% in 43 cases (87.5%), respectively]. Changes in disc height (DH) were significantly associated with lower pedicle screw angle, while lumbar lordosis and segment lordosis remained the same. Multivariate regression analysis showed a significant negative correlation between the upper and lower pedicle screw angles and the change in DH (P < 0.05). At 2 weeks post-operation, the VAS score for low back pain and the ODI had improved significantly compared to pre-operation (P < 0.05).

CONCLUSIONS

These results suggest that the Caudad insertion trajectory technique of pedicle screws may be an ideal alternative for the treatment of DLS.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR): ChiCTR1800020368.

Learning curves of robot-assisted pedicle screw fixations based on the cumulative sum test

BACKGROUND

In robot-assisted (RA) spine surgery, the relationship between the surgical outcome and the learning curve remains to be evaluated.

AIM

To analyze the learning curve of RA pedicle screw fixation (PSF) through fitting the operation time curve based on the cumulative summation method.

METHODS

RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively. Based on the cumulative sum of the operation time, the learning curves of the two surgeons were drawn and fit to polynomial curves. The learning curve was divided into the early and late stages according to the shape of the fitted curve. The operation time and screw accuracy were compared between the stages.

RESULTS

The turning point of the learning curves from Surgeons A and B appeared in the 18^th and 17^th cases, respectively. The operation time [150 (128, 188) min vs 120 (105, 150) min, P = 0.002] and the screw accuracy (87.50% vs 96.30%, P = 0.026) of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases. In the case of Surgeon B, the operation time (177.35 ± 28.18 min vs 150.00 ± 34.64 min, P = 0.024) was significantly reduced, and the screw accuracy (91.18% vs 96.15%, P = 0.475) was slightly improved after the surgeon completed 17 RA surgeries.

CONCLUSION

After completing 17 to 18 cases of RA PSFs, surgeons can pass the learning phase of RA technology. The operation time is reduced afterward, and the screw accuracy shows a trend of improvement.

Pedicle Screw Fixation with Percutaneous Vertebroplasty for Traumatic Thoracolumbar Vertebral Compression Fracture

Objective

This study aims to evaluate the clinical efficacy of percutaneous pedicle screw fixation (PPSF) combined with percutaneous vertebroplasty (PVP) for the treatment of the thoracolumbar vertebral compression fracture (VCF) without neurologic deficits.

Materials and Methods

This was a prospective observational study. Between January 2015 and December 2018, 62 patients who had suffered from traumatic thoracolumbar (VCF) burst fractures without neurologic deficits were included in this study. The patients were divided into two groups as follows: patients who underwent PPSF combined with PVP (PPSF-PVP Group; n = 24) and patients who underwent only PPSF (PPSF Group; n = 38). The patients were (PPSF and PPSF-PVP Group) followed up for more than 9 months. The kyphotic angle, compression ratio, and visual analog scale (VAS) score for back pain were analyzed and compared between the two groups.

Results

The patients were followed up for an average of 9.1 months. Hospital stay significantly decreased in PPSF-PVP Group (P < 0.001). The median VAS score significantly decreased after the surgery in both the groups (P < 0.005), and mean VAS scores in PPSF-PVP Group were significantly lower than those in PPSF Group. No significant (P > 0.005) changes in local kyphosis and the vertebral body height gains obtained at the end of the follow-up period in PPSF-PVP Group. However, local kyphosis increased significantly (P < 0.005) and the central and anterior vertebral body height decreased significantly (P < 0.005) when compared with the PPSF-PVP Group.

Conclusion

PPSF combined with PVP procedure is a good choice for the treatment of traumatic thoracolumbar VCF; however, due to the lack of long-term follow-up data, concern still exists regarding the effects of pedicle screw procedure after PVP.

Occipitocervical instrumented fixation utilising patient-specific C2 3D-printed spinal screw trajectory guides in complex paediatric skeletal dysplasia

PURPOSE

Instability of the craniocervical junction in paediatric patients with skeletal dysplasia poses a unique set of challenges including anatomical abnormalities, poor bone quality, skeletal immaturity and associated general anaesthetic risks. Instrumented fixation provides optimal stabilisation and fusion rates. The small vertebrae make the placement of C2 pedicle screws technically demanding with low margins of error between the spinal canal and the vertebral artery.

METHODS

We describe a novel clinical strategy utilising 3D-printed spinal screw trajectory guides (3D-SSTG) for individually planned C2 pedicle and laminar screws. The technique is based on a pre-operative CT scan and does not require intraoperative CT imaging. This reduces the radiation burden to the patient and forgoes the associated time and cost. The time for model generation and sterilisation was < 24 h.

RESULTS

We describe two patients (3 and 6 years old) requiring occipitocervical instrumented fixation for cervical myelopathy secondary to Morquio syndrome with 3D-SSTGs. In the second case, bilateral laminar screw trajectories were also incorporated into the same guide due to the presence of high-riding vertebral arteries. Registration of the postoperative CT to the pre-operative imaging revealed that screws were optimally placed and accurately followed the predefined trajectory.

CONCLUSION

To our knowledge, we present the first clinical report of 3D-printed spinal screw trajectory guides at the craniocervical junction in paediatric patients with skeletal dysplasia. The novel combination of multiple trajectories within the same guide provides the intraoperative flexibility of potential bailout options. Future studies will better define the potential of this technology to optimise personalised non-standard screw trajectories.

Safety and efficacy studies of kyphoplasty, mesh-container-plasty, and pedicle screw fixation plus vertebroplasty for thoracolumbar osteoporotic vertebral burst fractures

Background

Percutaneous kyphoplasty (PKP), percutaneous mesh-container-plasty (PMCP), and pedicle screw fixation plus vertebroplasty (PSFV) were three methods for osteoporotic vertebral burst fractures (OVBF). The purpose of the current study was to evaluate the clinical safety and efficacy of PKP, PMCP, and PSFV for OVBFs.

Methods

This retrospective study included 338 consecutive patients with thoracolumbar OVBFs who underwent PKP (n = 111), PMCP (n = 109), or PSFV (n = 118) and compared their epidemiological data, surgical outcomes, and clinical and radiological features. Clinical evaluations of VAS and ODI and radiological evaluations of height restoration, deformity correction, cement leakage, and canal compromise were calculated preoperatively, postoperatively, and 2 years postoperatively.

Results

Cement leakage (31/111 vs. 13/109 and 16/118, P < 0.05) was significantly higher in group PKP than in groups PSFV and PMCP. VAS and ODI scores improved postoperatively from 7.04 ± 1.15 and 67.11 ± 13.49 to 2.27 ± 1.04 and 22.00 ± 11.20, respectively, in group PKP (P < 0.05); from 7.04 ± 1.29 and 67.26 ± 12.79 to 2.17 ± 0.98 and 21.01 ± 7.90, respectively, in group PMCP (P < 0.05); and from 7.10 ± 1.37 and 67.36 ± 13.11 to 3.19 ± 1.06 and 33.81 ± 8.81, respectively, in the PSFV group (P < 0.05). Moreover, postoperative VAS and ODI scores were significantly higher in group PSFV than in groups PKP and PMCP (P < 0.05). However, VAS scores were not significantly different in the three groups 2 years postoperatively (P > 0.05). Postoperative anterior (81.04 ± 10.18% and 87.51 ± 8.94% vs. 93.46 ± 6.42%, P < 0.05) and middle vertebral body height ratio (83.01 ± 10.16% and 87.79 ± 11.62% vs. 92.38 ± 6.00%, P < 0.05) were significantly higher in group PSFV than in groups PMCP and PKP. Postoperatively, Cobb angle (10.04 ± 4.26° and 8.16 ± 5.76° vs. 4.97 ± 4.60°, P < 0.05) and canal compromise (20.76 ± 6.32 and 19.85 ± 6.18 vs. 10.18 ± 6.99, P < 0.05) were significantly lower in group PSFV than in groups PMCP and PKP.

Conclusion

Despite relatively worse radiological results, PMCP is a safe and minimally invasive surgical method that can obtain better short-term clinical results than PKP and PSFV for OVBFs.

Comparison of Percutaneous Kyphoplasty and Pedicle Screw Fixation for Treatment of Thoracolumbar Severe Osteoporotic Vertebral Compression Fracture with Kyphosis

BACKGROUND

Pedicle screw fixation (PSF) has been considered the preferred surgery for the treatment of severe osteoporotic vertebral compression fracture (sOVCF), and sOVCF was traditionally regarded as a relative contraindication to minimally invasive percutaneous kyphoplasty (PKP). Debate has continued regarding the selection of the best surgical method for sOVCF. In the present study, we compared the efficacy and safety between PKP and PSF.

METHODS

PKP was performed in 376 patients in group 1 and PSF in 121 patients in group 2. The visual analog scale (VAS), Oswestry disability index (ODI), local kyphotic angle, fractured vertebral body height, and complications were evaluated.

RESULTS

In the immediate postoperative analysis, the mean VAS score for group 1 was 2.4, significantly lower than the VAS score of 4.7 for group 2. The mean ODI score was 44.4% for group 1, lower than the ODI score of 57.1% for group 2. In addition, group 1 had had a significantly better ODI score at 1 year of follow-up. The local kyphotic angle and fractured vertebral body height had recovered better in group 2. In group 1, 113 patients had experienced cement leakage, and 29 patients had undergone PKP for adjacent new vertebral fractures. In group 2, 2 patients had developed wound infections, 4 had developed pneumonia, 2 had developed urinary tract infection, 3 had experienced asymptomatic screw loosening, and 7 had undergone PKP to treat new vertebral fractures and 1 had undergone removal of internal fixation because of back pain.

CONCLUSIONS

The results of the clinical and radiological evaluations showed that PKP is comparable to PSF for the treatment of sOVCF with kyphosis, with PKP having the advantages of minimal invasion, quick postoperative pain relief, and functional recovery.

Cluster phenomenon of vertebral refractures after posterior pedicle screw fixation in a patient with glucocorticosteroid-induced Kümmell's disease: a treatment dilemma

INTRODUCTION

Surgical treatments are usually preferred in patients with Kümmell's disease since it represents a failure of conservative treatment for osteoporotic vertebral compression fracture without evidence of spontaneous healing. However, the risk of postoperative refractures is much higher in patients with glucocorticosteroid-induced osteoporosis (GIOP) than in those with primary osteoporosis, possessing a therapeutic challenge and dilemma to orthopaedic surgeons.

CASE REPORT

We described a rare cluster phenomenon of vertebral refractures in a patient with GIOP subsequent to segmental internal fixation for the initial management of glucocorticosteroid-induced Kümmell's disease, and a review of the literature.

CONCLUSION

Our patient illustrates that clinicians should be aware of the significant management dilemma and possible disastrous outcome after surgical interventions for glucocorticosteroid-induced Kümmell's disease and, thus, pay much more attention to comprehensive perioperative antiosteoporotic medications for patients with GIOP in current medical treatment.

Effects of unilateral and bilateral pedicle screw fixation on symptoms and quality of life of patients with lumbar degenerative diseases

OBJECTIVE

This research was designed to probe into the effects of unilateral and bilateral pedicle screw fixation on the VAS scores of low back pain, leg pain, ODI indexes and JOA scores in patients with lumbar degenerative diseases.

METHODS

Totally 113 patients with lumbar degenerative diseases admitted in our hospital from February 2016 to December 2018 were collected as the research objects. Among them, 52 received bilateral pedicle screw fixation (BPSF) and 61 were treated by unilateral pedicle screw fixation (UPSF). The intraoperative blood loss, time of operation and hospitalization, and incidence of perioperative complications of the two groups were compared. The VAS scores, ODI indexes and JOA scores were assessed before operation and 6 and 12 months after treatment. The intervertebral fusion rates were compared, and the quality of life was evaluated by SF-36.

RESULTS

The intraoperative blood loss in the observation group (OG) was higher than that in the control group (CG) (P<0.05), while the time of operation and hospital stay were obviously shorter (P<0.05). There was no marked difference in the incidence of perioperative complications (P>0.05). Before treatment, there was no remarkable difference in the VAS scores of low back pain, leg pain, ODI indexes and JOA scores (P>0.05). At 6 and 12 months after treatment, the first two parameters were remarkably lower than those before treatment, but the rest of the parameters were dramatically higher (P<0.05). The VAS scores and ODI indexes of the OG were markedly lower than those of the CG, while the JOA scores, fusion rates and quality of life were obviously higher (P<0.05).

CONCLUSION

Bilateral pedicle screw fixation is valid and safe on lumbar degenerative diseases, which can improve patients' quality of life.

A comparison of three different surgery approaches and methods for neurologically intact thoracolumbar fractures: a retrospective study

OBJECTIVES

The purpose of this study was to evaluate and compare the feasibility, safety, and efficacy of conventional open pedicle screw fixation (COPSF), percutaneous pedicle screw fixation (PPSF), and paraspinal posterior open approach pedicle screw fixation (POPSF) for treating neurologically intact thoracolumbar fractures.

METHODS

We retrospectively reviewed 108 patients who were posteriorly stabilized without graft fusion. Among them, 36 patients underwent COPSF, 38 patients underwent PPSF, and 34 patients underwent POPSF. The clinical outcomes, relative operation indexes, and radiological findings were assessed and compared among the 3 groups.

RESULTS

All of the patients were followed up for a mean time of 20 months. The PPSF group and POPSF group had shorter operation times, lower amounts of intraoperative blood loss, and shorter postoperative hospital stays than the COPSF group (P < 0.05). The radiation times and hospitalization costs were highest in the PPSF group (P < 0.05). Every group exhibited significant improvements in the Cobb angle (CA) and the vertebral body angle (VBA) correction (all P < 0.05). The COPSF group and the POPSF group had better improvements than the PPSF group at 3 days postoperation and the POPSF group had the best improvements in the last follow-up (P < 0.05).

CONCLUSION

Both PPSF and POPSF achieved similar effects as COPSF while also resulting in lower incidences of injury. PPSF is more advantageous in the early rehabilitation time period, compared with COPSF, but POPSF is a better option when considering the long-term effects, the costs of treatment, and the radiation times.

Posterior thoracolumbar hemivertebra resection and short-segment fusion in congenital scoliosis: surgical outcomes and complications with more than 5-year follow-up

Background

Treatment of congenital hemivertebra is challenging and data on long-term follow-up (≥ 5 years) are lacking. This study evaluated the surgical outcomes of posterior thoracolumbar hemivertebra resection and short-segment fusion with pedicle screw fixation for treatment of congenital scoliosis with over 5-year follow-up.

Methods

This study evaluated 27 consecutive patients with congenital scoliosis who underwent posterior thoracolumbar hemivertebra resection and short-segment fusion from January 2007 to January 2015. Segmental scoliosis, total main scoliosis, compensatory cranial curve, compensatory caudal curve, trunk shift, shoulder balance, segmental kyphosis, and sagittal balance were measured on radiographs. Radiographic outcomes and all intraoperative and postoperative complications were recorded.

Results

The segmental main curve was 40.35° preoperatively, 11.94° postoperatively, and 13.24° at final follow-up, with an average correction of 65.9%. The total main curve was 43.39° preoperatively, 14.13° postoperatively, and 16.06° at final follow-up, with an average correction of 60.2%. The caudal and cranial compensatory curves were corrected from 15.78° and 13.21° to 3.57° and 6.83° postoperatively and 4.38° and 7.65° at final follow-up, with an average correction of 69.2% and 30.3%, respectively. The segmental kyphosis was corrected from 34.30° to 15.88° postoperatively and 15.12° at final follow-up, with an average correction of 61.9%. A significant correction (p < 0.001) in segmental scoliosis, total main curve, caudal compensatory curves and segmental kyphosis was observed from preoperative to the final follow-up. The correction in the compensatory cranial curve was significant between preoperative and postoperative and 2-year follow-up (p < 0.001), but a statistically significant difference was not observed between the preoperative and final follow-up (p > 0.001). There were two implant migrations, two postoperative curve progressions, five cases of proximal junctional kyphosis, and four cases of adding-on phenomena.

Conclusion

Posterior thoracolumbar hemivertebra resection after short-segment fusion with pedicle screw fixation in congenital scoliosis is a safe and effective method for treatment and can achieve rigid fixation and deformity correction.

Computed tomographic analysis of cervical spine pedicles in the adult Indian population

Background:

Cervical pedicle screw insertion is a technically demanding procedure that carries the risk of catastrophic damage to surrounding neurovascular structures. Here, we analyzed computed tomography (CT)-based three-dimensional cervical spine pedicle geometry to determine the level and sex-specific morphologic differences in the adult Indian population.

Methods:

The CT scans of 200 patients (2400 pedicles) without significant cervical spine pathology were collected. The mean pedicle width (PW), pedicle height (PH), pedicle axial length (PAL), and pedicle transverse angle (PTA) from C2 to C7 were measured.

Results:

The smallest mean PW was at C3 in both males (4.85 ± 0.73 mm) and females (4.31 ± 0.43 mm); 7.08% of all pedicles were found to have mean PW of <4 mm. The smallest mean PH was at C5 in both males (6.25 ± 0.67mm) and females (5.54 ± 0.52 mm). The smallest mean PAL was at C2 in both males (27.46 ± 1.69mm) and females (25.90 ± 1.88 mm). The mean PW, PH, and PAL were significantly greater in males than females at all levels (P < 0.05). The smallest mean PTA was at C3 in males (41.79 ± 2.53°) and at C7 in females (42.40 ± 2.27°).

Conclusion:

In the adult Indian population, the PW, PH and PAL were smaller than in the typical western population. Females had even smaller PW, PH and PAL as compared to males. We recommend that a small inventory of 3.5mm screws between 20mm to 30mm length be used in most cases where cervical pedicle screws are being used in the Indian population. However, individual vertebrae should be screened preoperatively with CT scans to exclude gross anatomical variations, especially in females and at the C3 and C4 levels.

Comparison of unilateral and bilateral polymethylmethacrylate-augmented cannulated pedicle screw fixation for the management of lumbar spondylolisthesis with osteoporosis

Background

Cannulated pedicle screw (CPS) augmented by polymethylmethacrylate (PMMA) can achieve satisfactory clinical efficacy in the treatment of lumbar spondylolisthesis with osteoporosis. However, accurate application of CPSs will help to avoid the difficulty of screw revision and reduce the incidence of PMMA-related complications. This study aimed to investigate the mid-term efficacy of CPS compared to unilateral and bilateral applications in this common lumbar degenerative disease.

Methods

May 2011 and May 2018, 50 patients with lumbar spondylolisthesis with osteoporosis who underwent posterior fixation and fusion using traditional pedicle screws or CPSs were included in the study. Patients were divided into two groups based on the application: the unilateral PMMA-augmented CPS group (UC, n = 29) and the bilateral PMMA-augmented CPS group (BC, n = 21). Operation time, blood loss, average hospitalization time, PMMA leakage, and other complications were recorded. The visual analog scale (VAS) and Oswestry disability index (ODI) scores were used to evaluate symptom recovery. Radiographic results were compared for intervertebral fusion and screw loosening.

Results

There were no significant differences in the baseline data of the two groups.

The VAS and ODI scores improved significantly after surgery (P < 0.05), with no significant differences between the groups (P > 0.05). The operation time and blood loss in the UC group were significantly lower than those in the BC group (P < 0.05). However, the loss of intervertebral disk height and Taillard index did not differ significantly between the groups. The rates of PMMA leakage in the UC and BC groups were 7.0% and 11.9%, respectively (P < 0.05). Bony fusion was achieved in all groups without screw loosening at the last follow-up. Only one patient experienced superficial infection in both groups, while cerebrospinal fluid leakage was observed in two patients in the BC group.

Conclusions

Unilateral application of PMMA-augmented CPS may provide adequate clinical safety and effectiveness in the surgical treatment of lumbar spondylolisthesis with osteoporosis.

Biomechanical Analysis of an Interspinous Process Fixation Device with In Situ Shortening Capabilities: Does Spinous Process Compression Improve Segmental Stability?

OBJECTIVE

The objective of this study was to characterize the biomechanical implications of spinous process compression, via in situ shortening of a next-generation interspinous process fixation (ISPF) device, in the context of segmental fusion.

METHODS

Seven lumbar cadaveric spines (L1-L4) were tested. Specimens were first tested in an intact state, followed by iterative instrumentation at L2-3 and subsequent testing. The order followed was 1) stand-alone ISPF (neutral height); 2) stand-alone ISPF (shortened in situ from neutral height; shortened); 3) lateral lumbar interbody fusion (LLIF) + ISPF (neutral); 4) LLIF + ISPF (shortened); 5) LLIF + unilateral pedicle screw fixation; 6) LLIF + bilateral pedicle screw fixation. A 7.5-Nm moment was applied in flexion/extension, lateral bending, and axial rotation via a kinematic test frame. Segmental range of motion (ROM) and lordosis were measured for all constructs. Comparative analysis was performed.

RESULTS

Statistically significant flexion/extension ROM reductions: all constructs versus intact condition (P < 0.01); LLIF + ISPF (neutral and shortened) versus stand-alone ISPF (neutral and shortened) (P < 0.01); LLIF + USPF versus ISPF (neutral) (P = 0.049); bilateral pedicle screw fixation (BPSF) versus stand-alone ISPF (neutral and shortened) (P < 0.01); LLIF + BPSF versus LLIF + unilateral pedicle screw fixation (UPSF) (P < 0.01). Significant lateral bending ROM reductions: LLIF + ISPF (neutral and shortened) versus intact condition and stand-alone ISPF (neutral) (P < 0.01); LLIF + UPSF versus intact condition and stand-alone ISPF (neutral and shortened) (P < 0.01); LLIF + BPSF versus intact condition and all constructs (P < 0.01). Significant axial rotation ROM reductions: LLIF + ISPF (shortened) and LLIF + UPSF versus intact condition and stand-alone ISPF (neutral) (P ≤ 0.01); LLIF + BPSF versus intact condition and all constructs (P ≤ 0.04).

CONCLUSIONS

In situ shortening of an adjustable ISPF device may support increased segmental stabilization compared with static ISPF.

Influence of Epidural Ropivacaine with or without Dexmedetomidine on Postoperative Analgesia and Patient Satisfaction after Thoraco-Lumbar Spine Instrumentation: A Randomized, Comparative, and Double-Blind Study

Study Design

This was a prospective, randomized, and double-blind study.

Purpose

Thoraco-lumbar spine surgery is associated with severe postoperative pain and can cause chronic pain. We aimed to compare the impact of epidural ropivacaine with and without dexmedetomidine on postoperative analgesia after thoracolumbar spine instrumentation wherein an epidural catheter was placed by the surgeon intraoperatively.

Overview of Literature

Very few studies have reported the use of epidural dexmedetomidine in spine surgeries. When used via the epidural route, dexmedetomidine is safe and efficacious and is associated with reduced rescue analgesia consumption, increased duration of analgesia, reduced pain scores, but not with major hemodynamic adverse effects.

Methods

Total 60 American Society of Anesthesiologists I–III adult patients aged 18–65 years who were scheduled to undergo thoraco-lumbar spine instrumentation were randomly allocated into group RD (epidural ropivacaine+dexmedetomidine) or group R (epidural ropivacaine plus saline). We aimed to compare the total rescue analgesic consumption on postoperative day 0, 1, and 2. Moreover, we studied the time to first rescue analgesia with visual analogue scale score <4 and the overall patient satisfaction scores.

Results

There was no difference between the demographic characteristics of the two groups. The mean value of total rescue analgesia consumption was 162.5±68.4 mg in the RD group and 247.5±48.8 mg in the R group. The mean time to first rescue analgesia was 594.6±83.0 minutes in the RD group and 103.6±53.2 minutes in the R group. The mean patient satisfaction score was 4.2±0.7 in the RD group and 3.2±0.6 in the R group. No patient had any respiratory depression or prolonged motor blockade during the postoperative period.

Conclusions

This study demonstrated the superior efficacy, in terms of postoperative analgesia and patient satisfaction scores, of epidural ropivacaine plus dexmedetomidine over that of ropivacaine alone in patients undergoing surgery for thoraco-lumbar spine.

Minimally Invasive Pedicle Screw Fixation With Indirect Decompression by Ligamentotaxis in Pathological Fractures

BACKGROUND

The spine is the most common site of bony metastases. Associated pathological fractures can result in pain, neurological deficit, biomechanical instability, and deformity.

OBJECTIVE

To present a minimally invasive technique for indirect decompression by ligamentotaxis in pathological fractures.

METHODS

A minimally invasive approach was utilized to perform percutaneous pedicle screw fixation in patients who required stabilization for pathological fractures. Preoperative and postoperative computed tomography and magnetic resonance imaging were used to compare spinal canal area and midsagittal canal diameter.

RESULTS

Two patients with newly diagnosed pathological fractures underwent minimally invasive treatment. Each presented with minimal epidural disease and a chief complaint of intractable back pain without neurological deficit. They underwent minimally invasive pedicle screw fixation with indirect decompression by ligamentotaxis. In each case, postoperative imaging demonstrated an increase in spinal canal area and midsagittal canal diameter by an independent neuroradiologist. There were no perioperative complications, and each patient was neurologically stable without evidence of hardware failure at their 5- and 6-mo follow-up visits.

CONCLUSION

Minimally invasive percutaneous fixation can be used to stabilize pathological fractures and provide indirect decompression by ligamentotaxis. This procedure is associated with minimal blood loss, low morbidity, and rapid initiation of radiation therapy. Only patients with minimal epidural disease, stenosis caused primarily by bony retropulsion, and mild-to-moderate deformity should be considered candidates for this approach.

Minimally Invasive Pedicle Screw Fixation Combined with Percutaneous Kyphoplasty Under O-Arm Navigation for the Treatment of Metastatic Spinal Tumors with Posterior Wall Destruction

OBJECTIVE

To evaluate the safety and efficacy of O-arm-guided minimally invasive pedicle screw fixation combined with percutaneous kyphoplasty for metastatic spinal tumors with posterior wall destruction.

METHODS

Patients who underwent minimally invasive pedicle screw fixation combined with percutaneous kyphoplasty for pathological vertebral fractures with posterior wall defects from January 2015 to December 2017 were followed up for 1 year. Visual analogue scale (VAS), SF-36 scores, middle vertebral height, posterior vertebral height, and the accuracy of pedicle screws were assessed preoperatively, postoperatively, and 1 year after surgery. The operation time, time from operation to discharge, blood loss, volume of bone cement, and leakage of bone cement were recorded.

RESULTS

Twenty-three patients (13 females and 10 males) who met our criteria were followed up for 1 year. The operation time of these patients was 162.61 ± 33.47 min, the amount of bleeding was 230.87 ± 93.76 mL, the time from operation to discharge was 4.35 ± 2.42 days, and the volume of bone cement was 3.67 ± 0.63 mL. The VAS score decreased from 7.04 ± 1.07 to 2.65 ± 0.93 before surgery (P = 0.000) and remained at 2.57 ± 0.79 1 year after surgery. Compared with the preoperative SF-36 scores for physical pain, physiological function, energy, and social function, the postoperative scores were significantly improved (P = 0.000). The height of the middle vertebral body increased from 14.47 ± 2.96 mm before surgery to 20.18 ± 2.94 mm (P = 0.000), and remained at 20.44 to 3.01 mm 1 year after surgery. The height of the posterior vertebral body increased from 16.56 ± 3.07 mm before operation to 22.79 ± 4.00 mm (P = 0.000), and 22.45 ± 3.88 mm 1 year after surgery. The 23 patients had a total of 92 pedicle screws; 85 screws were Grade A and 7 screws were Grade B. There was no leakage of bone cement after surgery.

CONCLUSION

In the short term, O-arm-guided minimally invasive pedicle screw fixation combined with kyphoplasty is safe and effective in the treatment of metastatic spinal tumors with posterior wall destruction.

Minimally invasive far lateral debridement combined with posterior instrumentation for thoracic and lumbar tuberculosis without severe kyphosis

Background

Anti-tuberculous therapy (ATT) alone cannot easily cure spine tuberculosis (STB) though it is the most essential treatment. Many studies have confirmed the efficacy of the surgical treatment of STB through anterior, anterolateral, posterior debridement, and intervertebral fusion or combined with internal fixation. However, the conventional surgical approach requires extensive exposure of the affected areas with high rates of morbidity and mortality. Recently, minimally invasive surgery has come into use to reduce iatrogenic trauma and relevant complications. Here, we introduced a novel technique for the treatment of thoracic and lumbar spine tuberculosis: minimally invasive far lateral debridement and posterior instrumentation (MI-FLDPI). In this study, we evaluated the technical feasibility, the clinical outcomes, and the postoperative complications.

Methods

We did a prospective, non-randomized study on this new technique. Twenty three patients (13 males) with thoracic or lumbar spine tuberculosis who underwent minimally invasive far lateral debridement and posterior instrumentation were included in the study. The preoperative comorbidities, operation duration, intra-operative hemorrhage, Cobb’s angles, and postoperative complications were recorded and analyzed. Clinical outcomes were evaluated by Visual Analog Scale (VAS), Oswestry Disability Index (ODI), neurological recovery, and eradication of tuberculosis. Radiological outcomes were evaluated by changes in Cobb’s angle and fusion status of the affected segments.

Results

The patients were followed for an average of 19 months (ranging from 12 to 36 months). At the final follow-up, CRP and ESR of all patients were normal. The VAS and ODI were significantly improved compared with preoperative values (P < 0.05). No evident progression of the kyphotic deformity was found after surgery. Twenty two patients showed spontaneous peripheral interbody fusion 1 year after surgery. There were no failure of the instrumentation even though a young female with drug-resistant tuberculosis showed no sign of interbody fusion at the third year follow-up. All the patients with preoperative neurological deficit showed complete recovery at the final follow-up.

Conclusions

MI-FLDPI using expandable tubular retractor could be recommended to treat thoracic and lumbar spine tuberculosis for the advantages of less trauma, earlier recovery, and less complications. Spontaneous peripheral interbody fusion was observed in nearly all the cases even without bone grafting.

Double-level myelopathy due to atlantoaxial dislocation (os odontoideum) and subaxial cervical spondylosis with angular kyphosis

Background:

The surgical management of cervical spondylotic myelopathy (CSM) attributed to os odontoideum (OO with atlantoaxial instability atlantoaxial instability) and subaxial kyphosis together pose significant surgical challenges.

Case Description:

An elderly male presented with CSM/myelopathy and severe quadriparesis attributed to an unstable OO and 87° fixed, subaxial cervical kyphosis. After performing a 540° spinal cord decompression with atlantoaxial fixation, the patient did well.

Conclusion:

Double-level CSM due to an unstable OO and subaxial kyphosis is rare and typically requires combined 540° decompression and stabilization.

Biomechanical Comparison of Stand-Alone and Bilateral Pedicle Screw Fixation for Oblique Lumbar Interbody Fusion Surgery-A Finite Element Analysis

BACKGROUND

The most common complication of oblique lumbar interbody fusion (OLIF) is endplate fracture/subsidence. The mechanics of endplate fracture in OLIF surgery are still unclear. The aim of the present study was to evaluate the biomechanical stability in patients undergoing OLIF surgery with stand-alone (SA) and bilateral pedicle screw fixation (BPSF) methods.

METHODS

A finite element model of the L1-L5 spinal unit was established and validated. Using the validated model technique, L4-L5 functional surgical models corresponding to the SA and BPSF methods were created. Simulations using the models were performed to investigate OLIF surgery. A 500-N compression force was applied to the superior surface of the model to represent the upper body weight, and a 7.5-Nm moment was applied to simulate the 6 movement directions of the lumbar spinal model: flexion and extension, right and left lateral bending, and right and left axial rotation. Finite element models were developed to compare the biomechanics of the SA and BPSF groups.

RESULTS

Compared with the range of motion of the intact lumbar model, that of the SA model was decreased by 79.6% in flexion, 54.5% in extension, 57.2% in lateral bending, and 50.0% in axial rotation. The BPSF model was decreased by 86.7% in flexion, 77.3% in extension, 76.2% in lateral bending, and 75.0% in axial rotation. Compared with the BPSF model, the maximum stresses of the L4 inferior endplate and L5 superior endplate were greatly increased in the SA model. The L4 inferior endplate stress was increased to 49.7 MPa in extension, and the L5 superior endplate stress was increased to 47.7 MPa in flexion, close to the yield stress of the lamellar bone (60 MPa).

CONCLUSIONS

OLIF surgery with BPSF could reduce the maximum stresses on the endplate, which might reduce the incidence of cage subsidence. OLIF surgery with the SA method produced more stress compared with BPSF, especially in extension and flexion, which might be a potential risk factor for cage subsidence.

Interspinous Process Fixation Device Versus Extended Pedicle Screw Fixation for Symptomatic Adjacent Segment Disease: 3-Year Retrospective Study

OBJECTIVE

In the present study, we compared the clinical and radiographic outcomes of an interspinous process fixation device (IFD) with those of extended pedicle screw fixation (PSF) for symptomatic adjacent segment disease (ASD) after lumbar fusion.

METHODS

The data from 109 patients with ASD treated with IFD (n = 48) or extended PSF (n = 61) from January 2009 to January 2016 were reviewed retrospectively. The clinical outcomes were measured using a visual analog scale (VAS) and the Oswestry disability index. The radiographic outcomes included the fusion rate, incidence of cage subsidence, and additional radiographic ASD.

RESULTS

The mean incision length, operative time, blood loss, and length of hospital stay were significantly lower in the IFD group (P < 0.001). Postoperative back and leg pain were relieved in both groups (P < 0.001). The mean preoperative VAS scores were 8.3 ± 1.3 and 8.5 ± 1.1 in the IFD and PSF groups and had improved to 2.8 ± 1.1 and 2.7 ± 1.2 after 36 months, respectively (P < 0.001). At 36 months postoperatively, 10 of the 56 patients (17.9%) in the PSF group had developed additional radiographic ASD compared with 2 of 44 patients (4.5%) in the IFD group.

CONCLUSION

Our results have demonstrated that in the treatment of symptomatic ASD, comparable clinical and radiologic outcomes can be achieved using IFD, which has a shorter skin incision, shorter operative time, less intraoperative blood loss, and shorter hospital stay than the extended PSF technique. Although not statistically significant, the IFD resulted in a lower ASD incidence compare with the PSF technique. Thus, IFD might be an alternative surgical method for symptomatic ASD after lumbar spine fusion.

A preliminary study of a novel robotic system for pedicle screw fixation: A randomised controlled trial

Background and objective

Existing orthopaedic robotic systems are almost restricted to provide guidance for trajectory direction. In the present study, a novel spinal robotic system with automatic drilling power was introduced. The aim of this study is to evaluate the feasibility and safety in pedicle screw ​insertion of posterior lumbar interbody fusion assisted by this novel robotic system.

Methods and materials

A randomised controlled trial was conducted for 17 participants who were required posterior lumbar interbody fusion process. Seven (3 M/4 F) were randomly assigned to the robot-assisted group (RA group), and the other ten (4 M/6 F) were assigned to the conventional technique group (FH group). A novel robotic system was used in the RA group. All measurements were based on postoperative computed tomography (CT) data. Accuracy of screw insertion was determined using the Gertzbein and Robbins Scale. Precision was measured by the entry point deviation distance and the trajectory rotation. Other variables included operation time, radiation time, length of stay, and screw-related complications.

Result

A total of 82 pedicle screws were placed in the 17 participants. In the RA group, 90.6% of screws placed were Grade A, and 9.4% were Grade B. In the FH group, 78.0% of screws were Grade A, 20.0% were Grade B, and 2.0% were Grade C. No statistical difference was found in the operation time, radiation time per case, and length of stay between both groups. The radiation time per screw is significantly lower in the RA group. No screw-related complications or revision occurred in the present study.

Conclusion

The outcome of screw accuracy of this robotic system was comparable with that of experienced surgeons, and no screw-related complication was found in the RA group during hospitalisation. In addition, radiation time per screw in the robotic group was significantly lower than that in the conventional group, which shows the potential to reduce radiation exposure of pedicle screw fixation assisted by this robotic system.

Translational potential

Our study shows that pedicle screw fixation assisted by "Orthbot" system is accurate and safe. It is concluded that this novel robotic system offers a new option for internal implantation in spine surgery.

Pedicle screw placement in spinal neurosurgery using a 3D-printed drill guide template: a systematic review and meta-analysis

Background

Many surgeons believe that the use of a 3D-printed drill guide template shortens operative time and reduces intraoperative blood loss compared with those of the free-hand technique. In this study, we investigated the effects of a drill guide template on the accuracy of pedicle screw placement (the screw placed completely in the pedicle), operative time, and intraoperative blood loss.

Materials/Methods

We systematically searched the major databases, such as Medline via PubMed, EMBASE, Ovid, Cochrane Library, and Google Scholar, regarding the accuracy of pedicle screw placement, operative time, and intraoperative blood loss. The χ² test and I² statistic were used to examine heterogeneity. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the accuracy rate of pedicle screw placement, and weighted mean differences (WMDs) with 95% CIs were utilized to express operative time and intraoperative blood loss.

Results

This meta-analysis included 13 studies (seven randomized controlled trials and six prospective cohort studies) involving 446 patients and 3375 screws. The risk of research bias was considered moderate. Operative time (WMD = − 20.75, 95% CI − 33.20 ~ − 8.29, P = 0.001) and intraoperative blood loss (WMD = − 106.16, 95% CI − 185.35 ~ − 26.97, P = 0.009) in the thoracolumbar vertebrae, evaluated by a subgroup analysis, were significantly different between groups. The 3D-printed drill guide template has advantages over the free-hand technique and improves the accuracy of pedicle screw placement (OR = 2.88; 95% CI, 2.39~3.47; P = 0.000).

Conclusion

The 3D-printed drill guide template can improve the accuracy rate of pedicle screw placement, shorten operative time, and reduce intraoperative blood loss.

A new lumbar fixation device alternative to pedicle-based stabilization for lumbar spine: In vitro cadaver investigation

Context: To evaluate the stability provided by a new bilateral fixation technique using an in vitro investigation for posterior lumbar segmental instrumentation.Design: Experimental cadaver study. In this study, we propose an alternative technique for a posterior lumbar fixation technique called "inferior-oblique transdiscal fixation" (IOTF).Setting: Study performed at Engineering Center for Orthopedic Research Exellence (ECORE) in Toledo University-Ohio.Participants: Six human lumbar cadaveric specimen used in this study.Interventions: In this study, we propose an alternative technique for a posterior lumbar fixation technique called "inferior-oblique transdiscal fixation" (IOTF). As a novel contribution to the classical technique, the entry point of the screw is the supero-lateral point of the intersecting line drawn between the corpus and the pedicle of the upper vertebra. This approach enables the fixation of two adjacent vertebrae using a single screw on each side without utilizing connecting rods.Outcome Measures: Flexion (Flex), extension (Ext), right and left lateral bending (LB & RB), and right and left axial rotation (LR & RR), and the position data were captured at each load step using the Optotrak motion measurement system and compared for IOTF and posterior transpedicular stabilization.Results: The Posterior stabilization system (PSS) and IOTF significantly reduced the ROM of L4-L5 segment compared to intact segment's ROM. During axial rotation (AR) IOTF fused index segment more than PSS. Besides this, addition of transforaminal lumbar interbody fusion (TLIF) cage improved the stabilization of IOTF system during flexion, extension and lateral bending. Whereas, PSS yielded better fusion results during extension compared to IOTF with and without interbody fusion cages.Conclusions: We hypothesized that the new posterior bilateral system would significantly decrease motion compared to the intact spine. This cadaver study showed that the proposed new posterior fusion technique IOTF fused the index segment in a similar fashion to the classical pedicle screw fusion technique.

Vertebral fracture in elderly female patients after posterior fusion with pedicle screw fixation for degenerative lumbar pathology: a retrospective cohort study

Background

There have been only a few reports of subsequent postoperative vertebral fracture following posterior spinal instrumentation fusion, especially in elderly female patients. This study attempted to evaluate the long-term prevalence of subsequent postoperative vertebral fracture in female patients aged 70 years and older who underwent spine decompression and fusion surgery with pedicle screw fixation.

Methods

We retrospectively reviewed prospectively collected data from 125 patients who met our inclusion and exclusion criteria. Patients were divided into 2 groups according to age: patients aged 70 years and older (Group A) and patients aged under 70 years of age (Group B). We evaluated incidence of subsequent postoperative vertebral fractures, type and timing of vertebral fractures, preoperative bone mineral density (BMD), preoperative diagnosis, surgical procedure, number of levels fused, extension of fusion to the lumbosacral junction, and presence of a transverse fixator.

Results

Baseline characteristics excluding patients’ age were not statistically different between the two groups. Preoperative BMD of Group A was an average 81.7% of the young adult mean (YAM) value and that of Group B was an average 85.1% YAM value. Subsequent postoperative vertebral fractures occurred in 22 (41.5%) of 53 in Group A. On the other hand, fracture occurred in 17 (23.6%) of 72 in Group B. There were significant differences between the groups (p = 0.02). The odds ratio for subsequent vertebral fracture was 2.4 (95% confidence interval: 1.1–5.2) in favor of Group A. Survival analysis showed that the rate of subsequent vertebral fracture was significantly higher in Group A (log-rank test, P = 0.007).

Conclusions

The incidence of subsequent vertebral fracture in patients aged 70 years and older was significantly higher than in patients aged under 70 years of age. In the case of pedicle screw fixation in elderly female patients, it is necessary to note the high risk of subsequent vertebral fracture despite short or non-rigid fusion. Vertebral fracture after posterior fusion surgery even for degenerative lumbar pathology could occur in more than one-third of female patients aged 70 years and older.

Freehand pedicle screw fixation: A safe recipe for dorsal, lumbar and sacral spine

Objective:

To determine outcome of freehand pedicle screw fixation for dorsal, lumbar and sacral fractures at a tertiary care centre in the developing world.

Methods:

A retrospective review was performed of 150 consecutive patients who underwent pedicle screw fixation from January 1, 2012 to 31^st December 2017. A total of 751 pedicle screws were placed. Incidence and extent of cortical breach by misplaced pedicle screw was determined by review of intra-operative and post-operative radiographs and/or computed tomography.

Results:

Among the total 751 free hand placed pedicle screws, four screws (0.53%) were repositioned due to a misdirected trajectory towards the disc space. six screws (0.79%) were identified to have cause moderate breach while four screws (0.53%) cause severe breach. There was no occurrence of iatrogenic nerve root damage or violation of the spinal canal.

Conclusion:

Free hand pedicle screw placement based on external landmarks showed remarkable safety and accuracy in our center. The authors conclude that assiduous adherence to technique and preoperative planning is vital to success.

Biomechanical testing of different posterior fusion devices on lumbar spinal range of motion

BACKGROUND

Recent minimal-invasive posterior fusion devices are supposed to provide stability and obtain fusion in combination with interbody cages in the instrumented segment. The aim of the present study is to evaluate the primary stability of two minimal-invasive posterior prototypes compared to an established spinous process plate and standard pedicle screw instrumentation.

METHODS

Seven fresh frozen human cadaver lumbar spines (L2-L5) were tested in a spinal testing device with a moment of 7.5 Nm. Spinal stability was determined as mean range of motion (RoM) in the segment L3/L4 during extension-flexion, lateral bending and axial rotation. The RoM was measured during five conditions: 1. intact; 2. working prototype composed of an interspinous device and process plates; 3. an established spinous process fixation device 4. working prototype of facet fixation and 5. pedicle screw fixation.

FINDINGS

All devices caused a significant reduction of RoM during extension-flexion. The RoM during lateral bending was significantly reduced to 37% (of intact) by pedicle screws and 68% by facet fixation prototype. During axial rotation the RoM was significantly reduced to 52% by pedicle screws and to 86% by facet fixation prototype. The other devices had no significant influence on RoM during lateral bending and axial rotation.

INTERPRETATION

The facet fixation prototype provided less primary stability compared to pedicle screws, but had significant advantages over spinous process fixation techniques. The results encourage further testing of this implant as a minimal-invasive approach for posterior fixation.