A circumferential decompression-based surgical strategy for multilevel ossification of thoracic posterior longitudinal ligament

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.

A Novel "De-tension"-guided Anterior Decompression Strategy-Thoracic Anterior Controllable Antedisplacement Fusion (TACAF) for Multilevel Ossification of Posterior Longitudinal Ligament in Thoracic Spine: A Retrospective Study with at Least 2-Year Follow-Up

OBJECTIVE

To propose a novel surgical strategy-thoracic anterior controllable antedisplacement fusion (TACAF) to treat multilevel thoracic ossification of the posterior longitudinal ligament (mT-OPLL), and investigate its safety and efficacy.

METHODS

Between January 2019 and December 2021, a total of 49 patients with thoracic myelopathy due to mT-OPLL surgically treated with TACAF were retrospectively reviewed. Patients' demographic data, radiologic parameters, and surgery-related complications, modified Japanese Orthopedic Association (mJOA) and visual analog scale (VAS) scores, thoracic kyphosis (TK), kyphosis angle in fusion area (FSK), thoracic curvature, spinal cord curvature, and curvature of curved rod in surgical region, diameter, and area of the spinal cord at the most compressed level were included.

RESULTS

All patients acquired satisfactory recovery of neurologic function and overall complication rate was low at the final follow up. The mean mJOA of the laminectomy+TACAF and Full Lamina Preservation +TACAF groups, respectively, was 3.74 ± 2.05, 3.67 ± 1.95 before surgery, and 9.97 ± 0.83, 9.80 ± 0.68 at the final followed up, with the recovery rate of 84.26% ± 14.20%, 82.79% ± 10.35%, as to VAS Scores. The mean FSK was 34.50 ± 4.46,35.33 ± 3.44 before surgery, and was restored to 20.97 ± 5.70, 22.93 ± 6.34 at the final followed up respectively, as to mean TK (P < 0.05). Spinal cord curvature was improved from 34.12 ± 3.59, 33.93 ± 3.45 before surgery to 19.47 ± 3.53, 18.80 ± 3.17 at the final follow-up respectively, as to thoracic curvature (P < 0.05). In addition, the area and diameter of the spinal cord was also significantly improved at the final follow up (all P < 0.05). The curvature of the thoracic pulp and thoracic vertebra is closely related to the curvature of the rod. There was no statistically significant difference in the incidence of the pelvis and the slope value of the sacrum.

CONCLUSIONS

This strategy provides a novel solution for the treatment of mT-OPLL with favorable recovery of neurological function, the tension of spinal cord, and fewer complications.

Factors Affecting the Surgical Outcomes of Patients Treated With "de-tension" Surgical Strategy for Multilevel Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine: A Minimum 2-year Follow-Up Study of 83 Patients in a Single Center

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To describe the clinical characteristics and surgical outcomes of patients with multilevel-ossification of the posterior longitudinal ligament (mT-OPLL), and to identify risk factors for unfavorable outcomes.

METHODS

Patients who were diagnosed with mT-OPLL and underwent one-stage thoracic posterior laminectomy combined with selective OPLL resection, spinal cord de-tension, and fusion surgery between August 2012 and October 2020 were recruited. Patients' demographic-, surgical- and radiological-related parameters were collected and analyzed. Neurological status was evaluated with mJOA score, and recovery rate (RR) was calculated using the Hirabayashi formula. According to RR, patients were divided into a favorable outcome group (FOG, RR ≥50%) and an unfavorable outcome group (UOG, RR <50%). Univariate and multivariate analyses were used to compare the difference between the 2 groups and to identify risk factors for unfavorable outcomes.

RESULTS

A total of 83 patients were included, with an average age of 50.6 ± 8.3 years. Cerebrospinal fluid leakage (60.2%) and transient neurological deterioration (9.6%) were the most common complications. The average mJOA score improved from preoperative 4.3 ± 2.2 to 9.0 ± 2.4 at the last follow-up, and the mean RR was 74.9 ± 26.3%. Disease duration, preoperative nonambulatory status, and the number of decompressed levels were identified as potential risk factors by Univariate analysis (all P < .05). Multivariate analysis showed that the preoperative disease duration and nonambulatory status were independent risk factors for unfavorable outcomes.

CONCLUSIONS

Long disease duration and nonambulatory status before surgery were independent risk factors for unfavorable outcomes.

[Intraoperative ultrasound assisted circumferential decompression for multilevel ossification of the posterior longitudinal ligament in thoracic vertebrae]

OBJECTIVE

To analyze the effect of short-segment circumferential decompression and the nerve function improvement in 30 cases of multilevel thoracic OPLL assisted by intraoperative ultrasound.

METHODS

A total of 30 patients with multilevel thoracic OPLL from January 2016 to January 2021 were enrolled, all of whom were located by intraoperative ultrasound and underwent circumferential decompression. There were 14 males and 16 females, with an average age of (49.3±11.4) years. The initial symptoms were mainly numbness and weakness of lower limbs (83.3%), and the mean duration of symptoms was (33.9±42.9) months (1-168 months). Neurological function was assessed by the Modified Japanese Orthopedic Association (mJOA) score (0-11) preoperative and at the last follow-up, in which the rate of neurological improvement was calculated by the Harabayashi method. The patients were divided into excellent improved group and poor improved group according to the improvement of neurological function. The age, body mass index (BMI), duration of symptoms, operation time, blood loss, mJOA score, surgical level, and cerebrospinal fluid leakage of the two groups were collected and analyzed for statistical differences. The factors influencing the improvement of neurological function were analyzed by univariate and multivariate Logisitic regression analysis.

RESULTS

The mean operation time was 137.4±33.8 (56-190) min, and the mean blood loss was (653.7±534.2) mL (200－3 000 mL). The preoperative mJOA score was 6.0±2.1 (2－9), and the last follow-up mJOA score was 7.6±1.9 (4－11), which was significantly improved in all the patients (P < 0.001). The average improvement rate of neurological function was 38.1%±24.4% (14.3%－100%), including 75%－100% in 4 cases, 50%－74% in 3 cases, 25%－49% improved in 14 cases, and 0%－24% in 9 cases. There was significant difference in intraoperative blood loss between the excellent improved group and the poor improved group (P=0.047). Intraoperative blood loss was also an independent risk factor in regression analysis of neurological improvement.

CONCLUSION

Thoracic circumferential decompression assisted with intraoperative ultrasound can significantly improve the neurological function of patients with multilevel OPLL and achieve good efficacy. The improvement rate of nerve function can be improved effectively by controlling intraoperative blood loss.

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.

Top 50 Most Cited Articles on Thoracic Ossification of Posterior Longitudinal Ligament

Study Design

Bibliometric analysis.

Objective

Over the last several decades, the field of thoracic ossification of the posterior longitudinal ligament (T-OPLL) has evolved unprecedentedly, and the literature on T-OPLL has increased significantly. The purpose of this study is to identify and review the top 50 most cited publications related to T-OPLL.

Methods

The most frequently cited 50 articles in this field until 30 October 2021 were identified by searching Web of Science. We ranked the articles based on the citation number. Through the bibliometric method, we evaluated the following information: article title, first author, year of publication, journal of publication, total number of citations, country, and study topic.

Results

The number of citations of included studies ranged from 20 to 108, with a mean number of 45.4. The journal Spine published most articles (20), followed by Spinal Cord (5), and European Spine (5). All of these articles were contributed by 38 first authors, Yamazaki (4), Fujimura (3), and Aizawa (3) who published more than 2 articles. In the respect of productive countries, Japan (39) contributed most papers. Tomita contributed the most cited article in 1990 on Spine, which was the first-ever report of circumferential decompression for thoracic myelopathy due to T-OPLL.

Conclusion

The top 50 influential articles on T-OPLL were identified and analyzed in this study. It will undoubtedly provide a comprehensive and detailed basis for the orthopedic and neurosurgery physicians to make a clinical decision and assimilate the research focus of spine surgery.

Intraoperative Ultrasound in Spine Decompression Surgery: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

The aim of this study was to review the current spine surgery literature to establish a definition for adequate spine decompression using intraoperative ultrasound (IOUS) imaging.

SUMMARY OF BACKGROUND DATA

IOUS remains one of the few imaging modalities that allows spine surgeons to continuously monitor the spinal cord in real-time, while also allowing visualization of surrounding soft tissue anatomy during an operation. Although this has valuable applications for decompression surgery in spinal canal stenosis, it remains unclear how to best characterize adequacy of spinal decompression using IOUS.

METHODS

We conducted a systematic search of multiple databases including: Medline, Embase, and Cochrane Central Register of Controlled Trials Strategy. Our search terms were spine, spinal cord diseases, decompression surgery, ultrasonogra-phy, and intraoperative period. We were interested in studies that used intraoperative use of ultrasound imaging in spinal decompression surgery for the cervical, thoracic, and lumbar spine. Study quality was evaluated using the Methodological Index for Non-Randomized Studies (MINORS).

RESULTS

Our search strategy yielded 985 of potentially relevant publications, 776 underwent title and abstract screening, and 31 full-text articles were reviewed. We found IOUS to be useful in spine surgery for decompression of degenerative cases in all regions of the spine. The thoracic spine was unique for IOUS-guided decompression of fractures, and the lumbar spine for decompressing nerve roots. Although we did not identify a universal definition for adequate decompression, there was common description of decompression that qualitatively described the ventral aspect of the spinal cord being "free floating" within the cerebrospinal fluid. Other measurable definitions, such as spinal cord diameter or spinal cord pulsatility, were not good definitions given there was insufficient evidence and/or poor reliability.

CONCLUSION

The systematic review examines the current literature on IOUS and spinal decompression surgery. We identified a common qualitative definition for adequate decompression involving a "free floating" spinal cord within the cerebrospinal fluid which indicates that the spinal cord is free from contact of the anterior elements.Level of Evidence: 1.

Motor-evoked potentials in the intraoperative decision-making of circumferential decompression via posterior approach for treating thoracic posterior longitudinal ligament ossification

BACKGROUND CONTEXT

Surgical treatment is indicated for symptomatic thoracic ossification of posterior longitudinal ligament (OPLL), and circumferential decompression (CD) is a promising option. However, the risk of postoperative paralysis in ventral decompression of CD is as high as 30%. Therefore, it is important to balance surgical outcomes and safety of ventral decompression.

PURPOSE

To investigate the role of intraoperative motor-evoked potential (MEP) changes in decision-making of one-staged CD via posterior approach for treating thoracic OPLL.

STUDY DESIGN

A retrospective cohort analysis PATIENT SAMPLE: Twenty-five thoracic OPLL patients in this study underwent posterior decompression (PD) alone, and the other 21 patients accepted CD.

OUTCOME MEASURES

Intraoperative MEP monitoring from both abductor hallucis and tibialis anterior, and modified Japanese Orthopaedic Association (mJOA) scores.

METHODS

MEPs were recorded in all patients before and after PD, and patients accepting CD underwent further MEP recordings after ventral decompression. According to MEP changes after PD, patients were divided into MEP improvement, MEP deterioration and no MEP change. Postoperative MEP improvement rates were measured in all tested muscles. Additionally, all patients accepted mJOA scores before and 2 years after operation.

RESULTS

Patients in both CD and PD groups exhibited improved mJOA scores after operation (p<.05), and both mJOA and MEP improvement rates were similar between these two groups (p>.05). In no MEP change group, patients accepting CD exhibited increased mJOA improvement rates compared with those accepting PD (p<.05). In MEP deterioration group, higher mJOA improvement rates were observed in PD group than in CD group (p<.05). In MEP improvement group, mJOA improvement rates were similar between CD and PD groups (p>.05).

CONCLUSIONS

Both CD and PD can effectively treat thoracic OPLL, and which of these two strategies can achieve better functional recovery may be related to different MEP changes after PD. Therefore, monitoring MEP changes may provide additional references in decision-making of one-staged CD for treating thoracic OPLL.

Enhanced Safety of Pedicle Subtraction Osteotomy Using Intraoperative Ultrasound

BACKGROUND

Pedicle subtraction osteotomy (PSO) can improve sagittal alignment but carries risks, including iatrogenic spinal cord and nerve root injury. Critically, during the reduction phase of the technique, medullary kinking or neural element compression can lead to neurologic deficits.

METHODS

We describe 3 cases of thoracic PSO and evaluate the feasibility, findings, and utility of intraoperative ultrasound in this setting.

RESULTS

Intraoperative ultrasound can provide a visual assessment of spinal cord morphology before and after PSO reduction and influences surgical decision making with regard to the final amount of sagittal plane correction. This modality is particularly useful for confirming ventral decompression of disc-osteophyte complex before reduction and also after reduction maneuvers when there is kinking of the thecal sac but uncertainty about the underlying status of the spinal cord. Intraoperative ultrasound is a reliable modality that fits well into the technical sequence of PSO, adds a minimal amount of operative time, and has few limitations.

CONCLUSIONS

We propose that intraoperative ultrasound is a useful supplement to standard neuromonitoring modalities for ensuring safe PSO reduction and decompression of neural elements.

Outcome of Thoracic Column Antedisplacement and Fusion in Treatment of Thoracic Myelopathy Caused by Ossification of Posterior Longitudinal Ligament: A Case Series Study

BACKGROUND

Up to date, surgical outcome of multilevel thoracic ossification of posterior longitudinal ligament (T-OPLL) with high canal occupation ratio is less satisfactory.

OBJECTIVE

To explore the result of thoracic column antedisplacement and fusion (TCAF) in treatment of multilevel T-OPLL with high canal occupation ratio.

METHODS

A total of 5 patients who underwent TCAF procedure for T-OPLL were retrospectively reviewed. Parameters including extent of OPLL, thickness of the maximal OPLL (max-OPLL), maximal canal occupying ratio (max-COR) of OPLL, effective canal diameter (ECD) at the max-OPLL level, antedisplacement distance of thoracic columns, ASIA grades, Japanese Orthopedic Association (JOA) scores, and complications were collected and analyzed at preoperation and the last follow-up.

RESULTS

All patients (5 F, mean age 61.0 yr, mean follow-up 18.0 months) underwent TCAF successfully and no spinal cord injury or cerebrospinal fluid leakage occurred. The mean extent of OPLL was 2.8 vertebral bodies. The mean preoperative thickness of the max-OPLL was 5.9 mm. The average antedisplacement distance of thoracic columns was 5.6 mm. The mean ECD was improved from 6.5 mm to 10.9 mm, and the max-COR was improved from 50.7% to 7.1% at last follow-up. Two patients showed improvement in ASIA grades and JOA scores were significantly improved from 5.6 points to 10.4 points at final follow-up. The overall therapeutic results of 1 patient were classified into good and 4 into fair at last follow-up.

CONCLUSION

TCAF may be a safe and effective procedure in treatment of multilevel T-OPLL with high canal occupation ratio.

Unplanned hospital readmission after surgical treatment for thoracic spinal stenosis: incidence and causative factors

BACKGROUND

To assess the incidence and causative factors of unplanned hospital readmission within 90 days after surgical treatment of thoracic spinal stenosis (TSS).

METHODS

Hospital administrative database was queried to identify patients who underwent surgical treatment of TSS from July 2010 through December 2017. All unplanned readmissions within 90 days of discharge were reviewed for causes and the rate of unplanned readmissions was calculated. Patients of unplanned readmission were matched 1:3 to a control cohort without readmission.

RESULTS

Twenty-one patients (incidence of 1.7 % in 1239 patients) presented unplanned hospital readmission within a 90-day period and enrolled as the study group, 63 non-readmission patients (a proportion of 1: 3) were randomly selected as the control group. Causes of readmission include pseudomeningocele (8 patients; 38 %), CSF leakage combined with poor incision healing (6 patients; 29 %), wound dehiscence (2 patient; 9 %), surgical site infection (2 patients; 9 %), spinal epidural hematoma (1 patient; 5 %), inadequate original surgical decompression (2 patients; 9 %). Mean duration from re-admission to the first surgery was 39.6 ± 28.2 days, most of the patients readmitted at the first 40 days (66.7 %, 14/21 patients). When compared to the non-readmitted patients, diagnosis of OPLL + OFL, circumferential decompression, dural injury, long hospital stay were more to be seen in readmitted patients.

CONCLUSIONS

The incidence of 90-day unplanned readmission after surgical treatment for TSS is 1.7 %, CSF leakage and pseudomeningocele were the most common causes of readmission, the peak period of readmission occurred from 10 to 40 days after surgery, patients should be closely followed up within this period.

Surgical strategy for non-continuous thoracic spinal stenosis: one- or two-stage surgery?

PURPOSE

Non-continuous thoracic spinal stenosis (NTSS) is a rare disease, but it is a challenging clinical entity for spine surgeons. However, few studies have focused on its treatment. Therefore, the purpose of this study was to provide surgical treatment guidelines for it by comparing the clinical outcomes of different surgical approaches.

METHODS

Patients who underwent thoracic decompression surgery for two diseased segments with two incisions (normal segments ≥ 3) between January 2010 and December 2018 were included. Among these patients, nine were treated with posterior decompression (PD) and circumferential decompression (CD) procedures in one-stage surgery (group A), 14 with PD and CD procedures in two-stage surgery (group B), 36 patients with PD procedures in one-stage surgery and 15 with PD procedures in two-stage surgery (group D). Medical records, operative time, blood loss and complications were reviewed. Neurologic status was assessed by the modified Japanese Orthopaedic Association scale for thoracic myelopathy.

RESULTS

Groups A, B, C and D were followed for 54.11 ± 20.51 months, 49.36 ± 29.30 months, 49.94 ± 31.94 months and 39.93 ± 26.18 months, respectively. When comparing groups A and B, operative time, blood loss and length of stay in hospital were significantly less in group A. However, the average recovery rate in group B was significantly higher than that in group A. In regard to groups C and D, group C showed a significantly shorter length of stay in hospital and lower rate of post-operative neurological deterioration. At final follow-up, groups C and D showed similar average recovery rates.

CONCLUSION

Different surgical procedures are suitable for different types of NTSS. For patients with NTSS mainly caused by posterior compression, PD via laminectomy in one-stage with two incisions can achieve satisfying clinical outcomes. Staged surgery, including CD and PD procedures, is recommended for patients with NTSS mainly caused by anterior compression.

"IV+V+VI" Circumferential Decompression Technique for Thoracic Myelopathy Caused by the Ossification of Posterior Longitudinal Ligament or Hard Disc Herniation

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to describe a novel posterior approach, circumspinal decompression technique "IV+V+VI" for ossification of the posterior longitudinal ligament (OPLL) or hard disc herniation (HDH) in thoracic spine and assess its safety and efficacy.

SUMMARY OF BACKGROUND DATA

Thoracic myelopathy caused by OPLL or HDH is a rare but intractable disorder that can only be effectively treated with surgery. Nevertheless, few studies have reported on a detailed resection of OPLL or HDH using a single posterior approach and no consistent procedures have been established.

METHODS

Fifteen consecutive patients with single-level OPLL or HDH who were treated with this novel technique at our center between January 2016 and June 2017 were recruited. The perioperative complications, operation time, blood loss, pre- and postoperative neurological statuses were recorded and analyzed. Neurological status was evaluated with a modified Japanese Orthopaedic Association (JOA) scale and the neurological recovery rate was calculated using the Hirabayashi's Method.

RESULTS

All the included patients underwent one-stage posterior circumferential decompression. The average age at surgery was 43.3 ± 12.8 years. Eight cases were diagnosed with HDH, four with OPLL, and three with OPLL+OLF (ossification of the ligamentum flavum). The mean operation time was 109.9 ± 25.3 minutes with an average blood loss of 433.3 ± 221.8 mL. The mean follow-up period was 33.1 ± 7.5 months. Five patients experienced a dural tear, whereas another case experienced a transient numbness in the right lower limb. All these patients were treated conservatively and their neurological function recovered well at the final follow-up. The average JOA score increased from 5.8 ± 1.9 before surgery to 10.2 ± 1.0 postoperatively, and the average recovery rate was 87.2%.

CONCLUSION

The "IV+V+VI" technique is a safe and effective method for thoracic OPLL and HDH resection. It can be used as a standard surgical procedure for thoracic spinal circumferential decompression.

LEVEL OF EVIDENCE

4.

Treatment of Thoracic Ossification of Posterior Longitudinal Ligament with One-Stage 360 Degree Circumferential Decompression Assisted by Piezosurgery

OBJECTIVES

To evaluate the safety and clinical efficacy of One-Stage 360 degree circular decompression for thoracic ossification of the posterior longitudinal ligament (TOPLL) assisted by piezosurgery.

MATERIALS AND METHODS

The present study enrolled 36 patients with TOPLL between August 2016 and February 2019. The average intraoperative bleeding volume of all 36 patients in this study is 1058.61 ±737.66 ml.

RESULTS

All patients did not experience any intraoperative complications such as spinal cord and nerve injuries, and 22 other complications related to decompression of OPLL cited in other literature; all of which were relieved after treatment. The resection time of single laminectomy was 3.43 ±0.49 min, and circular decompression was 42.06 ±14.22 min. At the last follow-up, the modified Japanese Orthopaedic Association (mJOA) score was 8.89 ±1.56, the recovery rate of spinal cord function was 64.2 ±21.2%, and the number of cases of spinal cord function deterioration was 0 (0%). The mJOA score of the last follow-up was negatively correlated with the time of circular decompression (r = 0.368, p ＜ 0.01) and age (r = 0.412, p = 0.026). The recovery rate of the spinal cord function was negatively correlated with the operation time of circular decompression (r = -0.325, p = 0.041) and the amount of intraoperative blood loss (r = -0.555, p = 0.028).

CONCLUSIONS

The use of piezosurgery can safely and effectively complete one-stage simple posterior TOPLL with 360-degree circular decompression. The incidence of complications is not high, and a good outcome can be obtained.

One-stage posterior surgery with intraoperative ultrasound assistance for thoracic myelopathy with simultaneous ossification of the posterior longitudinal ligament and ligamentum flavum at the same segment: a minimum 5-year follow-up study

BACKGROUND CONTEXT

Ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF) are not uncommon independent causes of thoracic myelopathy (TM); however, concomitant OPLL and OLF at the same segment is rare. The ideal surgical strategy remains controversial, and it is difficult for surgeons to balance sufficient neural decompression while simultaneously reducing the occurrence of postoperative neurological defect after circumferential decompression (CD). Aiming to solve this dilemma, we investigated a CD-based surgery using intraoperative ultrasound (IOU) assistance to evaluate spinal decompression sufficiency.

PURPOSE

The aims of this study are to evaluate the surgical outcomes and identify prognostic factors of one-stage posterior surgery with IOU assistance in patients with concomitant OPLL and OLF.

STUDY DESIGN/SETTING

Retrospective study of a single-center TM database with long-term follow-up.

PATIENT SAMPLE

Twenty-four patients with TM and concomitant OPLL and OLF.

OUTCOME MEASURES

Japanese Orthopaedic Association (JOA) score system for TM, recovery rate (RR), complication rate.

METHODS

Twenty-four patients' data were retrospectively reviewed. All patients initially underwent en bloc excisions of posterior spinal canal elements, and IOU was then used to evaluate spinal decompression sufficiency. If any compression of OPLL was confirmed in IOU, further CD procedure was performed. The JOA score was used to evaluate health-related quality of life. RR was calculated using the Hirabayashi formula. A RR ≥50% was considered favorable, and a RR <50% was considered unfavorable. The paired t test was performed to statistically compare the preoperative and postoperative JOA scores. The chi-squared test, rank sum test, and logistic regression analyses were performed to find variants associated with unfavorable surgical outcomes The prognostic factors were analyzed by Spearman correlation and Pearson correlation analyses.

RESULTS

The invasive CD procedure were avoided in 9 of 28 segments were avoided, with a mean blood loss of 1,458 mL. Seventeen patients experienced cerebrospinal fluid leakage, and 5 experienced immediate postoperative paralysis. The mean JOA score improved from 4.25±2.2 (preoperative) to 8.16±1.9 (final follow-up). The mean RR was 57.7%±29.4%. There was a significant difference (p<.01) between the preoperative and final follow-up JOA score. A comparison between the favorable and the unfavorable groups showed no significant differences in the evaluated factors, but the considerable blood loss was a significant risk factor for poor RR (p=.036, b=-0.43).

CONCLUSIONS

One-stage CD-based surgery via a posterior approach with IOU assistance for the treatment of concomitant OPLL and OLF led to significant functional improvement in the majority of patients. Under the premise of sufficient decompression, the postoperative paralysis rate reduced compared to that in previous studies. However, there were still high cerebral spinal fluid leakage rates. Considerable blood loss is a risk factor for poor RR.

The COL6A1 rs201153092 single nucleotide polymorphism, associates with thoracic ossification of the posterior longitudinal ligament

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is one of the most common factors that causes thoracic spinal stenosis, resulting in intractable myelopathy and radiculopathy. Our previous study reported that the rs201153092 polymorphism present in the collagen 6A1 (COL6A1) gene was a potentially pathogenic locus for the development of T-OPLL. The present study aimed to determine whether the rs201153092 mutation causes abnormal expression of COL6A1 in Han Chinese patients with T-OPLL, and to examine the effects of this mutation on osteogenesis by establishing a model of osteogenic differentiation. COL6A1 gene mutant and wild-type mouse 3T3-E1 embryonic osteoblast models were constructed to induce the differentiation of these cells into osteoblasts. The potential of the mutation site to induce abnormal expression of the COL6A1 gene and osteogenic markers was assessed via reverse transcription-quantitative PCR and western blot analyses. The results demonstrated that the rs201153092A mutation site resulted in significantly increased COL6A1 gene expression levels in the OPLL tissues obtained following clinical surgery. This mutation was shown to play an important role in the development of T-OPLL by regulating the overexpression of the COL6A1 gene and significantly increasing the expression levels of osteogenic markers. The findings of the present study suggested that the rs201153092A mutant variant could increase the expression levels of COL6A1 and consequently play a role in the pathogenesis of T-OPLL.

IL17RC affects the predisposition to thoracic ossification of the posterior longitudinal ligament

Background

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) can cause thoracic spinal stenosis, which results in intractable myelopathy and radiculopathy. The etiology of T-OPLL is unknown and the condition is difficult to treat surgically. Whole-genome sequencing identified a genetic variant at rs199772854 of the interleukin 17 receptor C (IL17RC) gene as a potentially pathogenic locus associated with T-OPLL. We aimed to determine whether the rs199772854A site mutation causes abnormal expression of the IL17RC in Han Chinese patients with T-OPLL and predict the possible pathogenic mechanisms of T-OPLL. Analyses were performed to determine whether IL17RC is involved in the pathogenicity of T-OPLL.

Methods

Peripheral blood and OPLL tissue were collected from a total of 72 patients with T-OPLL disease (36 patients carrying the rs199772854A site mutation in IL17RC and 36 wild-type patients). The expression of IL17RC was analyzed by enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, and Western blotting.

Results

rs199772854A mutation resulted in markedly increased IL17RC gene expression levels in peripheral blood samples and the OPLL tissue obtained following clinical surgery (P < 0.05).

Conclusions

The results suggest that the rs199772854A site mutation of IL17RC can significantly increase the expression of IL17RC. The IL17RC gene rs199772854A site polymorphism is a potential pathogenic mutation in T-OPLL disease, which may be associated with the occurrence of T-OPLL.

Surgical Outcomes According to Dekyphosis in Patients with Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine

Objective

Ossification of posterior longitudinal ligament (OPLL) in the thoracic spine may cause chronic compressive myelopathy that is usually progressive, and unfavorable by conservative treatment. Although surgical intervention is often needed, the standard surgical method has not been established. Recently, it has been reported that posterior decompression with dekyphosis is effective surgical technique for favorable clinical outcome. The purpose of this study was to evaluate the surgical outcomes in patients with thoracic OPLL according to dekyphosis procedure and to identify predictive factors for the surgical results.

Methods

A total of 25 patients with thoracic OPLL who underwent surgery for myelopathy from May 2004 to March 2017, were retrospectively reviewed. Patients with cervical myelopathy were excluded. We assessed the clinical outcomes according to various surgical approaches. The modified Japanese orthopedic association (JOA) scores for the thoracic spine (total, 11 points) and JOA recovery rates were used for investigating surgical outcomes.

Results

Of the 25 patients, 10 patients were male and the others were female. The mean JOA score was 6.7±2.3 points preoperatively and 8.8±1.8 points postoperatively, yielding a mean recovery rate of 53.8±31.0%. The mean patients’ age at surgery was 52.4 years and mean follow-up period was 40.2 months. According to surgical approaches, seven patients underwent anterior approaches, 13 patients underwent posterior approaches, five patients underwent combined approaches. There was no significant difference of the surgical outcomes related with different surgical approaches. Age (≥55 years) and high signal intensity on preoperative magnetic resonance (MR) image in the thoracic spine were significant predictors of the lower recovery rate after surgery (p<0.05). Posterior decompression with dekyphosis procedure was related to the excellent surgical outcomes (p=0.047). Dekyphosis did not affect the complication rates.

Conclusion

In this study, our result elucidated that old age (≥55 years) and presence of intramedullary high signal intensity on preoperative MR images were risk factors related to poor surgical outcomes. In the meanwhile, posterior decompression with dekyphosis affected favorable clinical outcome. Posterior approach with dekyphosis procedure can be a recommendable surgical option for favorable results.

Potential role of the IL17RC gene in the thoracic ossification of the posterior longitudinal ligament

The thoracic ossification of the posterior longitudinal ligament (T-OPLL) can cause thoracic spinal stenosis, which results in intractable myelopathy and radiculopathy. Our previous whole-genome sequencing study first reported rs199772854 in the interleukin 17 receptor C (IL17RC) gene as a potentially pathogenic loci for T-OPLL. The aim of the present study was to examine the effects of the IL17RC gene rs199772854A site mutation on osteogenesis by establishing a model of osteogenic differentiation. IL17RC gene mutation site and wild-type site mouse embryonic osteoblast (3T3-E1) models were constructed in order to induce the differentiation of the cells into osteoblasts. Whether the mutation site causes the abnormal expression of the IL17RC gene and osteogenic markers was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The IL17RC gene rs199772854A site mutation was demonstrated to play a biological role through the overexpression of its own gene, and also to significantly increase the expression levels of osteogenic markers. Furthermore, the mutation upregulated the expression of the key proteins, tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) and nuclear factor (NF)-κB, in the interleukin (IL)-17 signaling axis. On the whole, the findings of this study suggest that the IL17RC gene rs199772854A loci mutation propels mouse embryonic osteoblasts towards osteogenic differentiation and may play an important role in the pathogenesis of T-OPLL. The IL17RC gene may promote osteogenesis through the IL-17 signaling pathway and may thus be involved in the process of ectopic osteogenesis in T-OPLL.

Efficacy of posterior decompression and fixation based on ossification-kyphosis angle criteria for multilevel ossification of the posterior longitudinal ligament in the thoracic spine

OBJECTIVE The range of decompression in posterior decompression and fixation for ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) can be established using an index of spinal cord decompression based on the ossification-kyphosis angle (OKA) measured in the sagittal view on MRI. However, an appropriate OKA cannot be achieved in some cases, and posterior fixation is applied in cases with insufficient decompression. Moreover, it is unclear whether spinal cord decompression of the ventral side is essential for the treatment of OPLL. In this retrospective analysis, the efficacy of posterior decompression and fixation performed for T-OPLL was investigated after the range of posterior decompression had been set using the OKA. METHODS The MRI-based OKA is the angle from the superior margin at the cranial vertebral body of the decompression site and from the lower posterior margin at the caudal vertebral body of the decompression site to the prominence of the maximum OPLL. Posterior decompression and fixation were performed in 20 patients. The decompression range was set so that the OKA was ≤ 23° or the minimum if this value could not be achieved. Cases in which an OKA ≤ 23° could and could not be achieved were designated as groups U (13 patients) and O (7 patients), respectively. The mean patient ages were 50.5 and 62.1 years (p = 0.03) and the mean preoperative Japanese Orthopaedic Association (JOA) scores were 5.9 and 6.0 (p = 0.9) in groups U and O, respectively. The postoperative JOA score, rate of improvement of the JOA score, number of levels fused, number of decompression levels, presence of an echo-free space during surgery, operative time, intraoperative blood loss, and perioperative complications were examined. RESULTS In groups U and O, the mean rates of improvement in the JOA score were 50.0% and 45.6% (p = 0.3), the numbers of levels fused were 6.7 and 6.4 (p = 0.8), the numbers of decompression levels were 5.9 and 7.4 (p = 0.3), an echo-free space was noted during surgery in 92.3% and 42.9% of cases (p = 0.03), the operative times were 292 and 238 minutes (p = 0.3), and the intraoperative blood losses were 422 and 649 ml (p = 0.7), and transient aggravation of paralysis occurred as a perioperative complication in 2 and 1 patient, respectively. CONCLUSIONS There was no significant difference with regard to the recovery rate of the JOA score between patients with (group U) and without (group O) sufficient spinal cord decompression. The first-line surgical procedure of posterior decompression and fixation with the range of posterior decompression set as an OKA ≤ 23° before surgery involves less risk of postoperative aggravation of paralysis and may result in a better outcome.

Use of Ultrasonic Device in Cervical and Thoracic Laminectomy: a Retrospective Comparative Study and Technical Note

Multilevel severe compressive myelopathy is a challenging disorder for the surgeons, the aim of this study is to assess the efficacy and safety of a newly designed ultrasonic burr as an assistant tool to the ultrasonic scalpel in laminectomy for this disease. This is a retrospective comparative study, the included subjects were patients who received cervical and thoracic laminectomy using ultrasonic device (LUD, n = 9, 10 surgeries) and controls with the high-speed burr (LHB, n = 16). Fifteen patients (60.0%) showed severe cord occupancy and the average number of laminae operated was 3.5. Ultrasonic devices caused less blood loss (P = 0.02) and quicker operative time per level (P < 0.001) than LHB, and was associated with more operated laminae (P = 0.04). Preoperative JOA scores (P = 0.51), improvement rate (P = 0.47), and dural injury (P = 0.51) were not related to LUD. Our experience indicates ultrasonic devices are safe and effective for laminectomy treating multilevel and severe compressive myelopathy, the instrument could be used with ease especially for cases with ossified posterior longitudinal ligament and ossification of the ligamentum flavum, proper utility of the instrument is crucial to prevent complications.

Surgical Treatment for Ossification of the Posterior Longitudinal Ligament (OPLL) at the Thoracic Spine: Usefulness of the Posterior Approach

Various methods via anterior or posterior approach with or without spinal stabilization have been performed in accordance with the level and configuration of ossification of the posterior longitudinal ligament (OPLL) as the decompression surgery for thoracic myelopathy due to OPLL. Among them, anterior decompression at the middle thoracic level (T4/T5-T7/T8) is especially difficult to perform because of the special anatomical structures, where the spinal alignment is kyphotic and the thoracic cage containing circulatory-respiratory organs exist nearby. Of the anterior decompression procedures at this level, the posterior approach has various advantages compared to the anterior one. In the anterior approach, the procedure is complicated and the effect of decompression of the spinal cord can be obtained only by direct resection or anterior floating of the OPLL. However, complications such as spinal cord injury and dural tear are most likely to occur at that time. On the contrary, in the posterior approach, the procedure is simple, and various options to obtain decompression can be selected from, these are, laminectomy, laminoplasty, dekyphosis surgery, staged decompression surgery (Tsuzuki's method), circumferential decompression via posterior approach alone (Ohtsuka's method), and circumferential decompression via combined posterior and anterior approaches (Tomita's method). Among them, in laminectomy, laminoplasty, and dekyphosis surgery, anterior decompression can be obtained to some extent without performing direct procedure on the OPLL. In Ohtsuka's method, complete decompression can be obtained via posterior approach alone, although it is somewhat technically demanding. It is preferable to drop the shaved down and separated OPLL anteriorly instead of trying to remove it completely to avoid complications, especially in patients with severe adhesion between the dura mater and OPLL.

Risk Factors for Ineffectiveness of Posterior Decompression and Dekyphotic Corrective Fusion with Instrumentation for Beak-Type Thoracic Ossification of the Posterior Longitudinal Ligament: A Single Institute Study

BACKGROUND: Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is treated surgically with instrumented posterior decompression and fusion. However, the factors determining the outcome of this approach and the efficacy of additional resection of T-OPLL are unknown.

OBJECTIVE: To identify these factors in a prospective study at a single institution.

METHODS: The subjects were 70 consecutive patients with beak-type T-OPLL who underwent posterior decompression and dekyphotic fusion and had an average of 4.8 years of follow-up (minimum of 2 years). Of these patients, 4 (6%; group R) had no improvement or aggravation, were not ambulatory for 3 weeks postoperatively, and required additional T-OPLL resection; while 66 (group N) required no further T-OPLL resection. Clinical records, gait status, intraoperative ultrasonography, intraoperative neurophysiological monitoring (IONM), plain radiography, computed tomography and magnetic resonance imaging findings, and Japanese Orthopaedic Association (JOA) score were compared between the groups.

RESULTS: Preoperatively, patients in group R had significantly higher rates of severe motor paralysis, nonambulatory status, positive prone and supine position test, no spinal cord floating in intraoperative ultrasonography, and deterioration of IONM at the end of surgery (P &lt; .05). In preoperative radiography, the OPLL spinal cord kyphotic angle difference in fused area, OPLL length, and OPLL canal stenosis were significantly higher in group R (P &lt; .05). At final follow-up, JOA scores improved similarly in both groups.

CONCLUSION: Preoperative severe motor paralysis, nonambulatory status, positive prone and supine position test, radiographic spinal cord compression due to beak-type T-OPLL, and intraoperative residual spinal cord compression and deterioration of IONM were associated with ineffectiveness of posterior decompression and fusion with instrumentation. Our 2-stage strategy may be appropriate for beak-type T-OPLL surgery.

Cerebrospinal Fluid Leakage after Thoracic Decompression

Objective:

The objective of this study is to review cerebrospinal fluid leakage (CSFL) after thoracic decompression and describe its regular and special features.

Data Sources:

Literature cited in this review was retrieved from PubMed and Medline and was primarily published during the last 10 years. “Cerebrospinal fluid”, “leakage”, “dural tears”, and “thoracic decompression” were the indexed terms. Relevant citations in the retrieved articles were also screened to include more data.

Study Selection:

All retrieved literature was scrutinized, and four categories were recorded: incidence and risk factors, complications, treatment modalities, and prognosis.

Results:

CSFL is much more frequent after thoracic decompression than after cervical and lumbar spinal surgeries. Its occurrence is related to many clinical factors, especially the presence of ossified ligaments and the adhesion of the dural sac. While its impact on the late neurological recovery is currently controversial, CSFL increases the risk of other perioperative complications, such as low intracranial pressure symptoms, infection, and vascular events. The combined use of primary repairs during the operation and conservative treatment postoperatively is generally effective for most CSFL cases, whereas lumbar drains and reoperations should be implemented as rescue options for refractory cases only.

Conclusions:

CSFL after thoracic decompression has not been specifically investigated, so the present study provides a systematic and comprehensive review of the issue. CSFL is a multi-factor-related complication, and pathological factors play a decisive role. The importance of CSFL is in its impact on the increased risk of other complications during the postoperative period. Methods to prevent these complications are in need. In addition, though the required treatment resources are not special for CSFL after thoracic decompression, most CSFL cases are conservatively curable, and surgeons should be aware of it.

Treatment for thoracic ossification of posterior longitudinal ligament with posterior circumferential decompression: complications and managements

Background

The complications and corresponding managements for patients with thoracic ossification of posterior longitudinal ligament (TOPLL) who were treated with posterior circumferential decompression have not been systematically summarized yet.

Methods

Twenty-one patients with TOPLL who received posterior circumferential decompression between February 2010 and December 2014 were retrospectively reviewed. The patients’ basic characteristics, surgical duration, intraoperative blood loss, Japanese Orthopaedic Association (JOA) scores, and intraoperative and postoperative complications, and the adopted managements were summarized.

Results

The patients were averagely aged 52.1 ± 8.3 (range 32–67) years and included 10 males and 11 females. The mean operation time was 4.0 ± 0.9 (range 2.5–6) h and blood loss was 1619 ± 704 (range 800–4000) ml. Patients were followed up for 24.5 ± 1.2 (range 12–36) months. The average JOA score of patients was significantly elevated from 4.5 ± 1.4 (preoperative) to 7.4 ± 2.4 (P < 0.001, mean recovery rate 57.73%) on the second postoperative day and 7.8 ± 2.2 (P < 0.001, mean recovery rate 60.36%) at the final follow-up visit, respectively. There were 23 cases of complications that occurred in 12 patients, including 10 cases of intraoperative hemorrhage, 5 of cerebrospinal fluid leakage, 4 of intercostal nerve palsy, 3 of neurological deterioration, and 1 of superficial infection. After the corresponding treatment, these complications were recovered during the follow-up except 1 case of postoperative neurological deterioration did not exhibit improvement.

Conclusions

Posterior circumferential decompression is effective for TOPLL but causes complications which need to be proactively prevented and treated. If treated properly, most complications can be recovered with satisfactory outcomes.

Cerebrospinal Fluid Leakage after Surgeries on the Thoracic Spine: A Review of 362 Cases

Study Design

A retrospective clinical review.

Purpose

To describe the incidence of cerebrospinal fluid leakage (CSFL) after thoracic decompression and examine the CSFL predisposing clinical factors.

Overview of Literature

CSFL is a common complication following thoracic decompression but has not been sufficiently addressed in former studies.

Methods

A cohort of 362 cases of thoracic decompression from February of 2005 to June of 2013 was examined. The case medical records were reviewed and the occurrence of CSFL and the related clinical parameters were noted. The incidence of CSFL for the entire cohort and each surgical approach were described. Besides, the relationship between CSFL and other clinical parameters were assessed, of which odds ratio values of all CSFL-associated parameters were calculated using multivariate logistic regression analysis.

Results

The incidence of CSFL for the entire cohort was 32.3%. Different surgical approaches had different incidences of CSFL, and circumferential decompression had the highest incidence. Though many different clinical parameters were related to the occurrences of CSFL, being older than 52 years, having ossification of the posterior longitudinal ligament or having longer operative segments than 3 vertebrae were significant risk factors for CSFL (p<0.05). Besides, surgeries on the mid-thoracic spine had an increased risk of CSFL (p<0.05).

Conclusions

From our analysis, CSFL was a common complication after thoracic decompression with the incidence of up to 32.3%. This study identified the predisposing clinical factors, and spinal surgeons should be aware of these risk factors to reduce its incidence.

One-staged combined decompression for the patients with cervico-thoracic tandem spinal stenosis

PURPOSE

To report the techniques and safety of one-staged combined decompression for the patients with tandem spinal stenosis (TSS) at cervical and thoracic spine.

METHODS

Sixteen TSS subjects, who received combined decompression from Aug 2005 to Feb 2012, were reviewed. The essentials of our surgical strategy included: choosing patients with TSS from cervical to upper or middle thoracic spine, using one single posterior incision, simplifying surgical maneuvers and performing circumferential decompression for thoracic compression if it was indicated. The Japanese Orthopedic Association (JOA) scale for cervical myelopathy was employed to evaluate the neurological status, and Hirabayashi's system to assess neurological recovery rate.

RESULTS

The average operation duration, blood loss and postoperative hospitalization were 242.8 ± 89.9 min, 1581.3 ± 1237.2 ml and 11.9 ± 7.5 days, respectively. Six subjects (37.5 %) suffered instant neurological deterioration. Other complications included cerebrospinal fluid leakage (10 subjects, 62.5 %), new radiculopathy (two subjects), urinary infection, lung infection and pulmonary thromboembolism. Four subjects received extra-thoracic decompression due to the remaining anterior compression in one subject and new emerging compression in other three subjects. Eventually, mean JOA score was elevated from 9.8 ± 2.1 to 13.7 ± 2.7 after this procedure, and the neurological recovery of seven subjects was rated as excellent, four as good, two as fair, three as unchanged or deteriorated. The overall recovery rate was 53.7 %.

CONCLUSION

Combined cervico-thoracic decompression could provide fair neurological outcomes for patients with cervico-thoracic TSS, but it was complicated with high rate of undesirable postoperative events. So, more efforts should be done against its eventful postoperative course before its wide application.