Ultrasonic bone scalpel for thoracic spinal decompression: case series and technical note

Safety and efficacy of ultrasonic bone scalpel compared with a high-speed drill in spinal surgery: our experience in sixty cases

PURPOSE

In this study, we aimed to evaluate the effectiveness and safety of UBS (Ultrasonic Bone Scalpel) and HSD (High-speed drill) for performing anterior or posterior decompressions in patients with pathologies in cervical and lumbar regions.

METHODS

Between October 2022 and June 2024, 60 patients underwent surgery in which a UBS (Sonopet UST-2001; Stryker Neuro Spine ENT, MI, USA) and High-speed Midas Rex MR8 (Medtronic, Fort Worth, TX, USA) drill was used. Informed consent was obtained from all patients. The study included 27 men and 33 women with a mean age of 59,5 ± 14.6 years (range: 28-85). The following patient data were recorded: preoperative and postoperative JOA scores, intraoperative blood loss, and operative time for decompression in lumbar and cervical region.

RESULTS

In UBS group, the mean intraoperative blood loss was 166.0 ± 64.3 ml. The mean preoperative and postoperative JOA scores were 4.5 ± 1.0 and 8.6 ± 1.8 and the mean postoperative follow-up duration was 6.1 ± 4.4 months in UBS group. The mean intraoperative blood loss was 221.2 ± 93.4 ml in HSD group. The mean preoperative and postoperative JOA scores were 5.2 ± 1.1 and 8.2 ± 1.2 in HSD group. In the HSD group, the blood loss (BL) value was significantly higher (p < 0.05) compared to the UBS group. The preoperative/postoperative JOA score improvement in the UBS group was significantly higher (p < 0.05) than in the HSD group.

CONCLUSIONS

The UBS can be safely used in spinal surgery. It reduces intraoperative blood loss and provide better clinical improvement. Authors would like to emphasize that the UBS resects the bone with oscillatory movements rather than rolling motions and this mechanism of action is important in reducing the risk of dura mater injury.

Iceberg floating technique of ventral decompression for thoracic spinal stenosis and myelopathy: Technical note and preliminary results

OBJECTIVE

To propose a novel technique named iceberg floating technique for treating severe thoracic spinal stenosis and myelopathy caused by ventral compression and investigate its clinical results.

METHODS

From October 2020 to January 2023, patients presenting with severe thoracic spinal stenosis and myelopathy caused by ossification of posterior longitudinal ligamentum (OPLL) or calcified thoracic disc herniation (CTDH) were included in this study. All patients were treated with iceberg floating technique, the Oswestry Disability Index (ODI) score preoperatively and postoperatively at the final follow-up were reviewed. Pre-and post-operative CT and MRI scans were applied for the assessment of decompression.

RESULTS

A total of 13 patients were included in this study, consisting of six females and seven males, with an average age of 51.6 years (ranging from 30 to 66 years). There were six cases diagnosed as OPLL and seven cases as CTDH. The mean follow-up period after the operation was 13.0 months (ranging from 7 months to 32 months). The average duration of the operation was 194.6 min (ranging from 130 min to 270 min), with an average intraoperative blood loss of 540.8 ml (ranging from 240 ml to 1200 ml). The average ODI score before the operation was 68.6 (ranging from 50 to 84), which decreased to an average score of 20.3 (ranging from 12 to 28) at follow-up. All patients achieved MCID at follow-up.

CONCLUSIONS

The iceberg floating technique is a safe and effective technique for the treatment of thoracic spinal stenosis and myelopathy caused by OPLL and CTDH.

Sodium hyaluronate and acupotomy bone decompression alleviates inflammatory responses in patients with knee osteoarthritis

OBJECTIVE

Knee osteoarthritis (KOA), predominantly affecting middle-aged and elderly populations, induces localized joint pain and functional impairment. It was to evaluate the effectiveness of acupotomy bone decompression (ABD) combined with sodium hyaluronate (SH) intra-articular injection on inflammatory responses in treating KOA.

METHODS

Clinical data from 128 patients with KOA were retrospectively collected, categorized into SH group (n = 55) and ABD + SH group (n = 73). Pain was assessed using the visual analogue scale (VAS), knee joint function was evaluated, and knee joint balance and gait parameters were measured. The status of articular cartilage and bone marrow edema was evaluated using quantitative magnetic resonance imaging (MRI). Interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-3, MMP-9, and hypersensitive C-reactive protein (hs-CRP) were detected.

RESULTS

ABD + SH group showed drastic reductions in VAS scores, decreased indices of different axial balances, and increased stride length and walking speed versus the SH group (P < 0.05). Quantitative MRI examination revealed that relative to the SH group, ABD + SH group exhibited increased thickness of articular cartilage and reduced area of bone marrow edema post-treatment (P < 0.05). Post-treatment levels of hs-CRP, IL-6, IL-1β, TNF-α, MMP-3, and MMP-9 were markedly lower in the ABD + SH group versus SH group (P < 0.05). Moreover, the clinical effective rate in the ABD + SH group was drastically superior to the SH group (95.9% vs. 78.2%, P < 0.05).

CONCLUSION

Combining ABD with SH treatment for KOA effectively alleviates patient pain and inflammatory responses.

Efficacy of Preoperative Autologous Blood Donation for Surgical Treatment of Thoracic Spinal Stenosis: A Propensity-Matched Cohort Study

OBJECTIVE

Thoracic spinal stenosis (TSS) surgeries necessitate a substantial amount of allogeneic blood resources. However, the efficacy of preoperative autologous blood donation (PABD) in TSS surgery has not been clearly evaluated. Therefore, we aimed to evaluate the efficacy of PABD for TSS surgery.

METHODS

This study is a retrospective study. Totally 397 patients who underwent TSS surgeries at our institution from January 2019 to June 2023 were included. Propensity score matching (PSM) was used to make the PABD and Non-PABD groups comparable at baseline. Regarding outcome measures, the incidence and amount of allogeneic blood transfusion, changes in postoperative hemoglobin and hematocrit levels, occurrence of postoperative complications, medical costs, drainage time, length of hospital stay, and postoperative neurological function were analyzed. The outcomes were compared between the matched PABD (n = 79) and Non-PABD (n = 79) groups. Univariate analysis methods were used for statistical analysis, including independent samples t-test, Wilcoxon rank-sum test, and chi-square test.

RESULTS

The incidence of allogeneic blood transfusion (8.9% vs. 25.3%, p = 0.006) and volume of intraoperative red blood cell (RBC) transfusion (10.12 ± 54.52 vs. 122.78 ± 275.00 mL, p < 0.001) in the PABD group were significantly lower than those in the Non-PABD group. The PABD group had significantly higher average postoperative hemoglobin and hematocrit levels than the Non-PABD group at 1, 3, and 5 days after surgery (p < 0.05). Similarly, the PABD group exhibited a smaller reduction in hemoglobin and hematocrit levels compared with the Non-PABD group on 1, 3, and 5 days postoperatively. There were no significant intergroup differences in terms of transfusion-related complications, medical expenses, neurological function, length of hospital stay, or drainage time. Notably, PABD was an independent protective factor of allogeneic transfusion in the multivariate regression analysis (OR = 0.334, 95%CI = 0.051-0.966).

CONCLUSIONS

PABD can effectively reduce the incidence of allogeneic blood transfusion and amount of allogeneic blood in TSS surgeries with safety. It also significantly improved the postoperative hemoglobin and hematocrit levels. Under the premise of clear indications, PABD is worth promoting for the surgical treatment of TSS.

Posterior Thoracic Antidisplacement and Fusion Surgery for a Special Type of Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine: Indications and Preliminary Clinical Results of 2-Year Follow-Up

OBJECTIVE

To describe a novel technique, posterior thoracic antidisplacement and fusion (PTAF), for a special type of ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL), and to evaluate its safety and efficacy.

METHODS

From July to December 2020, 5 consecutive patients with beak-type T-OPLL located at the thoracic vertebral body level underwent PTAF surgery. Their demographic data, radiological parameters, perioperative complications, and surgery-related findings were recorded and analyzed. The surgical outcomes were assessed using a modified Japanese Orthopedic Association scale, and the recovery rate was calculated using the Hirabayashi's method.

RESULTS

All patients were followed up for at least two years. The mean thickness of OPLL was 9.4 ± 1.0 mm, and the OPLL spinal canal occupying ratio was 67.7% ± 8.5%. Postoperatively, the mean antidisplacement distance of OPLL was 8.1 ± 1.8 mm, and the average shortened distance of the spinal column was 6.0 ± 1.13 mm. The mean operation time and blood loss were 158.2 ± 26.3 minutes and 460 ± 89.4 mL, respectively. Perioperative complications were cerebrospinal fluid leakage and instrument failure, 2 cases each. The mean modified Japanese Orthopedic Association score was increased from 3.6 ± 2.9 before surgery to 9.4 ± 3.0 at the last follow-up, and the average recovery rate was 84.2 ± 30.5%.

CONCLUSIONS

The preliminary clinical outcomes indicate that PTAF is a safe and effective method for the treatment of beak-type T-OPLL, which has its apex located at the vertebral body level and has a high spinal canal occupation ratio.

Application of Piezosurgery in Revision Surgery through Posterior Approach for Infection after Percutaneous Vertebral Augmentation: Technique Note with Case Series

OBJECTIVES

Pyogenic spondylitis after vertebral augmentation (PSVA) is a severe complication and even threatens the life of patients. How to deal with infectious bone cement is a big problem for surgeons. The application of piezosurgery has advantages in removal the infectious bone cement in limb bone and spinal laminectomy, but it is rarely used in PSVA. So, the present study aimed to introduce the application of piezosurgery in revision surgery for PSVA and report the preliminary radiological and clinical results.

METHODS

The data of nine patients with PSVA who had undergone revision surgery were retrospectively reviewed between May 2017 and January 2023 in our hospital. The technique of removal of infectious bone cement and lesion by piezosurgery and the reconstruction of the spinal stability were described, and the operation time and intraoperative blood loss were recorded. Postoperatively, radiographs and computed tomography scans were reviewed to evaluate the condition of bone cement removal, control of infection, and bone fusion. Oswestry disability index (ODI) and visual analog scale (VAS) were assessed pre- and postoperatively, and clinical outcomes were assessed using Odom's criteria.

RESULTS

All patients achieved satisfactory tainted bone cement cleaning and restoration of spinal alignment. The surgical time was 258.8 ± 63.2 (160-360) min, and the intraoperative blood loss was 613.3 ± 223.8 (300-900) mL. The VAS score decreased from 7.0 (6-8) points preoperatively to 2.4 (1-4) points postoperatively. The ODI index decreased from 71% (65%-80%) preoperatively to 20% (10%-30%) postoperatively. The patient's VAS and NDI scores after operation were significantly improved compared with those before surgery (p ≤ 0.05). Odom's outcomes were good for all patients in the last follow-up, and all patients reported satisfactory results.

CONCLUSIONS

Piezosurgery can effectively remove large blocks of infectious bone cement through a posterior approach while avoiding nerve and spinal cord damage. We cautiously suggest that a one-stage posterior approach using piezosurgery is an alternative option for surgical treatment of PSVA.

The Ultrasonic Bone Scalpel does not Outperform the High-Speed Drill: A Single Academic Experience

BACKGROUND

Spinal decompression and osteotomies are conventionally performed using high-speed drills (HSDs) and rongeurs. The ultrasonic bone scalpel (UBS) is a tissue-specific osteotome that preferentially cuts bone while sparing the surrounding soft tissues. There is ongoing investigation into its ability to optimize peri- and postoperative outcomes in spine surgery. The purpose of this study was to compare the intraoperative metrics and complications during a transition period from HSD to UBS.

METHODS

A single-institution, single-surgeon retrospective analysis was conducted of patients undergoing spine surgery from January 2020 to December 2021. Statistical analyses were performed to detect associations between the surgical technique and outcomes of interest. A P value < 0.05 was considered statistically significant.

RESULTS

A total of 193 patients met the inclusion criteria (HSD, n = 100; UBS, n = 93). Multivariate logistic regression revealed similar durotomy (P = 0.10), nerve injury (P = 0.20), and reoperation (P = 0.68) rates. Although the estimated blood loss (EBL) and length of stay were similar, the operative time was significantly longer with the UBS (192.81 vs. 204.72 minutes; P = 0.03). Each subsequent surgery using the UBS revealed a 3.1% decrease in the probability of nerve injury (P = 0.026) but had no significant effects on the operative time, EBL, or probability of durotomy or reoperation.

CONCLUSIONS

The UBS achieves outcomes on par with conventional tools, with a trend toward a lower incidence of neurologic injury. The expected reductions in EBL and durotomy were not realized in our cohort, perhaps because of a high proportion of revision surgeries, although these might be dependent on surgeon familiarity, among other operative factors. Future prospective studies are needed to validate our results and further refine the optimal application of this device in spine surgery.

Learning Curve and Clinical Outcomes of Ultrasonic Osteotome-based En Bloc Laminectomy for Thoracic Ossification of the Ligamentum Flavum

OBJECTIVE

Despite rapid advances in minimally invasive surgery, en bloc laminectomy remains the most common surgical approach for treating thoracic ossification of the ligamentum flavum (TOLF). However, the learning curve of this risky operation is rarely reported. Therefore, we aimed to describe and analyze the learning curve of ultrasonic osteotome-based en bloc laminectomy for TOLF.

METHODS

Among 151 consecutive patients with TOLF who underwent en bloc laminectomy performed by one surgeon between January 2012 and December 2017, we retrospectively analyzed their demographic data, surgical parameters, and neurological function. Neurological outcome was evaluated with the modified Japanese Orthopaedic Association (mJOA) scale, and the Hirabayashi method was used to calculate the neurological recovery rate. The learning curve was assessed with logarithmic curve-fitting regression analysis. Univariate analysis methods were used for statistical analysis, including t-test, rank sum test, and chi-square test.

RESULTS

A total of 50% of learning milestones could be reached in approximately 14 cases, and the asymptote in 76 cases. Therefore, 76 of the 151 enrolled patients were defined as the "early group," and the remaining 75 were delimitated as the "late group" for comparison. There was a significant intergroup difference in the corrected operative time (94.80 ± 27.77 vs 65.93 ± 15.67 min, P < 0.001) and the estimated blood loss (median 240 vs 400 mL, P < 0.001). The overall follow-up was 83.1 ± 18.5 months. The mJOA significantly increased from a median of 5 (IQR: 4-5) before the surgery to 10 (IQR: 9-10) at the last follow-up (P < 0.001). The overall complication rate was 37.1%, and no significant intergroup difference was found, except for the incidence of dural tears (31.6% vs 17.3%, p = 0.042).

CONCLUSION

Initially, mastering the en bloc laminectomy technique using ultrasonic osteotome for TOLF treatment can be challenging, but the surgeon's experience improves as the operative time and blood loss decrease. Improved surgical experience reduced the risk of dural tears but was not associated with the overall complication rate or long-term neurological function. Despite the relatively long learning curve, en bloc laminectomy is a secure and valid technique for TOLF treatment.

Ultrasonic bone scalpel in spine surgery

Background

Spine surgery has always been considered technically demanding even in the hands of the most experienced surgeon on account of close proximity of vital soft tissue structures. Technical advancements over the last few decades have been crucial for the progress of this complex speciality which not only increased the surgical accuracy, but patient safety as well. Ultrasonic devices are one such innovation based on piezoelectric vibrations, patented by Fernando Bianchetti, Domenico Vercellotti, and Tomaso Vercellotti in 1988.

Methods

We did an extensive literature search on ultrasonic devices and their applications in the field of spine surgery.

Results

We present the various ultrasonic bone devices available including their physical, technologic and clinical aspects in spine surgery. We also attempt to cover the limitations and future advances of Ultrasonic bone scalpel (UBS) in particular, which would be interesting and informative for any spine surgeon who is novice in this field.

Conclusion

UBS has been found to be safe and effective in all forms of spine surgeries offering distinct advantages over conventional instruments, although limited by an inherent learning curve.

Clinical progression of ossification of the ligamentum flavum in thoracic spine: a 10- to 11-year follow-up study

BACKGROUND

Thoracic ossification of ligamentum flavum (TOLF) can be asymptomatic and progress insidiously. But, long-term follow-up results of clinical progression of TOLF are still unknown.

METHODS

The clinical progression of 81 patients with TOLF at our center, followed for 10 to 11 (mean, 10.3) years from May 2010 to November 2021, were analyzed. Among them, 51 patients with thoracic myelopathy were caused by single- or multi-segment TOLF, and received partial TOLF resection (30 patients) or total TOLF resection (21 patients). The remaining 30 patients showed TOLF on imaging examinations, but TOLF was not the responsible compressing factor causing myelopathy and with no TOLF resection. The mJOA score (total 11 scores) and spinal operation were used to evaluate the clinical progression at follow-up.

RESULTS

During the 10- to 11-year follow-up of 81 TOLF patients, 71 (87.7%) had no deterioration of neurological function, and 10 (12.3%) patients had deterioration of neurological function and had another spinal operation, including only 4 (4.9%) suffered thoracic myelopathy caused by the progression of TOLF; 6 (7.4%) for other spinal diseases: 2 (2.5%) had fall damage and acute spinal cord injury at the TOLF level; 2 (2.5%) had thoracic myelopathy caused by ossification of posterior longitudinal ligament (OPLL); 2 (2.5%) had cervical spondylosis and received cervical operation.

CONCLUSIONS

Most TOLF (87.7%) patients had no clinical progression and received no reoperations for TOLF in the ten-year dimension (mean, 10.3 years). Narrow spinal canal for TOLF increases the risk of traumatic paraplegia.

Clinical effect of channel assisted cervical key hole technology combined with ultrasonic bone osteotome in the treatment of single segment cervical spondylotic radiculopathy

OBJECTIVE

To explore the clinical effect and operating skills of channel assisted Cervical Key Hole technology combined with Ultrasonic Bone Osteotome (CKH-UBO) in the treatment of single segment cervical spondylotic radiculopathy (CSR).

METHODS

From June 2018 to June 2020, 14 patients diagnosed with CSR and treated with channel assisted CKH-UBO were collected. The duration of the disease, the length of the incision, the operation time, the amount of bleeding during the operation, the length of hospitalization and the complications were recorded. The Range Of Motion (ROM) and the stability of the surgical segment were recorded before and after the operation. Visual analog scale (VAS), neck disability index (NDI) and modified macnab efficacy evaluation criteria were used to evaluate the surgical efficacy.

RESULTS

The operative segments of the enrolled patients were all lower cervical vertebrae. The average incision length was 2.0 ± 0.1 cm, the operation time was 42.2 ± 5.7 min, the intraoperative bleeding volume was 32.7 ± 4.1 ml, and the hospital stay was 5.6 ± 1.2 days. There was no difference in ROM between preoperative and 3 months and 1 year after operation (P > 0.05), and all patients did not have segmental instability. The VAS scores of neck pain before surgery, 3 days after surgery, 3 months after surgery, and 1 year after surgery were 5.6 ± 1.2, 1.6 ± 0.6, 1.1 ± 0.7, 0.6 ± 0.5, and the VAS scores of upper limb pain were 6.2 ± 1.2, 1.7 ± 0.7, 1.1 ± 0.6, 0.6 ± 0.5. The NDI scores of upper limb pain before surgery, 3 days after surgery, 3 months after surgery, and 1 year after surgery were 36.7 ± 3.5, 9.8 ± 2.4, and 3.9 ± 1.5, 1.8 ± 1.0, The VAS and NDI scores at all follow-up time points after operation were significantly lower than those before operation (P < 0.001). One year after operation, the curative effect was evaluated according to the modified macnab evaluation standard, and the excellent and good rate was 100%. The complication rate was 6.25%.

CONCLUSION

Channel assisted CKH-UBO for single segment CSR has the advantages of short operation time, reliable clinical effect, high safety and low complication rate, which is worthy of clinical promotion.

Angled Ultrasonic Bone Curette-Assisted Circumferential Decompression for Thoracic Myelopathy Caused by Severely Anterior Ossification

Objective

Thoracic myelopathy caused by severe anterior ossification is often progressive and fails to respond to conservative treatment. Removal of the compressing ossification is the most effective method but is hard to operate. In this study, we describe a novel one‐stage posterior circumferential decompressive procedure assisted by an angled ultrasonic bone curette (UBC) for thoracic myelopathy caused by severe anterior ossification and evaluate its safety and efficacy.

Methods

The current study enrolled 15 consecutive patients (five men and 10 women) with thoracic myelopathy caused by severely anterior ossification between January 2017 and December 2019. All patients underwent posterior circumferential decompression assisted by angled UBC and segmental instrumentation with interbody fusion. At the time of surgery, the average age was 58.6 ± 6.3 years (47–70 years). Before and after surgery, the patient data, clinical manifestation, operative levels, blood loss, operative time, perioperative complications, Japanese Orthopaedic Association (JOA) score were recorded and analyzed retrospectively.

Results

All patients had successful one‐stage posterior circumferential decompression to remove anterior ossifications directly. There were 12 cases of OPLL, two cases of a calcified giant herniated disc, and one case of osteophyte. The average operation time was 153.4 ± 53.4 min (77–242 min), with a mean blood loss of 463.5 ± 155.8 mL (240–780 mL). The average length of stay in the hospital was 14.3 ± 4.7 days (9–25 days) and the mean follow‐up duration was 20.8 ± 8.8 months (12–39 months). Almost all patients had subjective improvement in motor power and gait. The average preoperative JOA score was 4.5 ± 1.6, which improved to 9.0 ± 1.8 at the final follow‐up. Postoperative differences in the overall JOA scores showed significant improvement (F = 105.446, p < 0.01). The overall recovery rate at the final examination scored 70.9% ± 25.0%. According to Hirabayashi's classification, eight cases were rated as excellent, four as good, two as fair, and one as unchanged. No patient was graded as deteriorated. Two patients (13.3%) experienced intraoperative cerebrospinal fluid leakage, while two cases (13.3%) experienced unilateral intercostal neuralgia, and only one (6.7%) encountered acute neurological deterioration. All these patients were treated conservatively and their neurological function improved significantly. At the follow‐up, there was no evidence of neurological deterioration.

Conclusion

Circumferential decompression assisted by angled UBC can preserve more posterior elements of the involved levels, maintaining an intact pleura and reducing the operation time and blood loss for thoracic myelopathy caused by severe anterior ossification. It is a safe, effective, and technically feasible method to provide surgeons with a new option for thoracic spinal circumferential decompression.

A new "de-tension"-guided surgical strategy for multilevel ossification of posterior longitudinal ligament in thoracic spine: a prospective observational study with at least 3-year follow-up

BACKGROUND CONTEXT

Multilevel ossification of the posterior longitudinal ligament in thoracic spine (mT-OPLL) is a rare but clinically significant spinal condition. Various surgical methods have been developed to address this disease. However, the outcomes are commonly unfavorable, and no standard surgical strategy has been established. To solve this problem, we introduced a new surgical strategy based on an innovative decompression concept, namely "de-tension."

PURPOSE

This study aimed to investigate the safety and efficacy of this new treatment, and to establish an improved surgical strategy.

STUDY DESIGN

A prospective observational study with at least 3 years of follow-up.

PATIENT SAMPLE

Fifty-one patients with consecutive mT-OPLL who were treated between August-2012 and June-2018 were enrolled in this study.

OUTCOME MEASURES

A modified Japanese Orthopedic Association (mJOA) scale assessing thoracic spine, recovery rate (RR), and surgical complications.

METHODS

All patients underwent 1-stage thoracic posterior laminectomy, selective OPLL resection, and spinal column shortening with/without reduction of kyphosis (dekyphosis). Initially, we recommended that when thoracic kyphosis of T1-T12 in sagittal reconstruction CT (TK) was less than 20°, no dekyphosis should be performed; when this angle was greater than 20°, dekyphosis could be conducted. Patients' demographic data, radiological findings, and intra/postoperative complications were recorded and analyzed. Neurological status was evaluated with mJOA score and RR. The correlation of preoperative TK or kyphosis angle in fusion area (FSK) with postoperative dekyphosis angle and spinal column shortening distance (SD) were respectively evaluated by Pearson correlation analysis.

RESULTS

Cerebrospinal fluid leakage (58.8%) and neurological deterioration (15.7%) were the most common complications. Average mJOA score was improved from preoperative 4.0±2.1 to 8.9±2.4 at the last follow-up, and the mean RR was 71.3±33.7%. There was no correlation between preoperative TK and SD (p=.56) or between preoperative FSK and SD (p=.21), but dekyphosis angle was significantly correlated with TK (r=0.504, p<.01) and FSK (r=0.5734, p<.01). TK of 24.6° and FSK of 23.0° were determined as the critical angles for dekyphosis, and a modified surgical strategy was formulated.

CONCLUSIONS

This new strategy provided a novel solution for mT-OPLL, and was proved to be safe and effective during long-term follow-up. Further rigorously designed large-scale prospective studies are needed to validate our findings.