The incidence and risk factors of postoperative neurological deterioration after posterior decompression with or without instrumented fusion for thoracic myelopathy

S8 Navigation system combined with an ultrasonic osteotome for three-dimensional real-time dynamic visualization decompression to reduce postoperative neurological deterioration in thoracic ossification of the ligamentum flavum

BACKGROUND

Posterior laminectomy is a standard treatment for thoracic ossification of the ligamentum flavum (TOLF), but it often leads to neurological deterioration during surgery. This study aimed to reduce iatrogenic neurological deterioration by using an S8 navigation system combined with an ultrasonic osteotome for three-dimensional real-time dynamic visualization decompression.

METHODS

A retrospective analysis was conducted on patients who underwent laminectomy and internal fixation for TOLF in our centre from January 2016 to January 2023. Patients were divided into a visualization group (S8 navigation + ultrasonic bone scalpel) and a control group (ultrasonic bone scalpel) based on the use of three-dimensional real-time dynamic visualization decompression technology. Intraoperative multimodal neuroelectrophysiological monitoring (IONM) was used to collect somatosensory evoked potential and motor evoked potential data. We compared the incidence of intraoperative neurological deterioration indicated by IONM alarms between the two groups. Neurological and motor functions were assessed via the American Spinal Injury Association (ASIA) classification system and the modified Japanese Orthopaedic Association (m-JOA) score for thoracic myelopathy. Follow-ups were conducted at 1, 3, 6, and 12 months postsurgery, and the data from both groups were compared. Other clinical indicators included decompression time per laminectomy segment, intraoperative blood loss, intraoperative dural ossification, hospitalization duration, and drainage tube placement time. We also analysed intraoperative and postoperative complications.

RESULTS

A total of 91 patients with thoracic ossification of the ligamentum flavum were included, with a follow-up period of 12-18 months. The visualization group consisted of 41 patients, and the control group included 50 patients. The incidence of neurological deterioration indicated by IONM in the visualization group (9.8%) was significantly lower than that in the control group (30.0%) (P = 0.014). The immediate postoperative ASIA grade change value ≤ - 1 was lower in the visualization group (9.8%) than in the control group (34.0%) (P = 0.006); A similar trend was observed at the 12 month follow-up (2.4% vs. 20.0%, P = 0.022). The m-JOA scores at 1, 3, 6, and 12 months postsurgery were higher in the visualization group than in the control group (P < 0.05). The visualization group also had shorter lamina decompression times per segment and less intraoperative blood loss (P < 0.05). The incidence of nondural ossification cerebrospinal fluid leakage was lower in the visualization group (2.4%) than in the control group (18.0%) (P = 0.018). Additionally, nerve root injury was lower in the visualization group (0%) than in the control group (10.0%) (P = 0.037). Postoperative CT scans revealed no ossification residue in the visualization group, whereas 7 cases (14.0%) were observed in the control group (P = 0.013).

CONCLUSION

The S8 navigation system combined with an ultrasonic osteotome for three-dimensional real-time dynamic visualization decompression significantly reduces the incidence of intraoperative neurological deterioration, improves postoperative motor function recovery, and reduces decompression time per vertebral segment, intraoperative bleeding, and complications such as cerebrospinal fluid leakage. This technology is safe and reliable and offers a promising option for spinal surgeons in treating thoracic ossification of the ligamentum flavum.

Comparison of Surgical Results of the Bridge Crane Technique Versus Laminectomy for the Treatment of Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum

STUDY DESIGN

A retrospective study.

OBJECTIVES

This study aimed to evaluate the safety and effectiveness of the bridge crane technique versus laminectomy for the treatment of thoracic myelopathy caused by ossification of the ligamentum flavum (OLF).

METHODS

Totally 41 patients who underwent surgical decompression due to thoracic OLF from May 2017 to June 2018 in our institution were enrolled in this study and were divided into group BG (bridge crane technique, n = 19) and group L (laminoectomy, n = 22). Demographic data was collected from medical records and the modified Japanese Orthopaedic Association (JOA) scoring system was used to evaluate the neurological outcomes during the follow-up. Surgery-related complications were analyzed.

RESULTS

The mean duration of follow-up was comparable between group BG (19.4 ± 1.5 months) and group L (19.6 ± 1.4 months). No statistical differences were observed between two groups in terms of gender, age, duration of symptoms, preoperative occupying rate, involved levels, operation time, intraoperative blood loss, and complications. The JOA score significantly increased at the final follow-up in both groups. However, patients in group BG had higher JOA score and recovery rate (P < 0.05). Four patients in group L experienced complications, including 3 cerebrospinal fluid (CSF) leakage and one postoperative hematoma. Only one patient in group BG had CSF leakage.

CONCLUSION

The results of this study suggested that bridge crane technique may be relatively safe and effective for patients with symptomatic thoracic OLF with more satisfactory clinical improvement. However, high-quality studies are still required to validate the results of this study.

"White cord syndrome after cervical or thoracic spinal cord decompression. Haemodynamic complication or mechanical damage? An understimated nosographic entity"

The ischemia-reperfusion mechanism is believed to be responsible for parenchymal damage caused by temporary hypoperfusion and worsened by the subsequent attempt of reperfusion. This represents a true challenge for physicians of several fields, including neurosurgeons. A limited number of papers have shed the light on a rare pathological condition that affects patients experiencing an unexplained neurological deficit after spine surgery, the so-called "white cord syndrome". This entity is believed to be caused by an "ischemia-reperfusion" injury on the spinal cord, documented by a post-operative intramedullary hyperintensity on T2 weighted MRI sequences. To date, the cases of white cord syndrome reported in literature mostly refer to cervical spine surgery. However, the analysis of several reviews focusing on spine surgery outcome suggest that post-operative neurological deficits of new onset could be charged to a mechanism of ischemia-reperfusion, even if the physiopathology of this event is seldom explored or at least discussed. The same neuroradiological finding can suggest a mechanical damage due to surgical inappropriate manipulation. On this purpose, we performed a systematic revision of literature with the aim to identify and analyze all the factors potentially contributing to ischemic-reperfusion damage of the spinal cord that may potentially complicate any spinal surgery, without distinction between cervical or thoracic segment. Finally, we believe that post-operative neurological deficit after spinal surgery constituting the "white cord syndrome", could be underreported, while both neurosurgeons and patients should be fully aware of this rare but potentially devasting complication burdening cervical and thoracic spine surgery.

Paraplegia after Hypotension with Pneumothorax Episode during Thoracic Spine Tumor Surgery

Paraplegia after spine surgery is a catastrophic complication. Here, we present a patient who, following laminectomy and fusion for decompression of metastatic tumor, developed paraplegia. We tried to find out the possible reason for the paraplegia. Due to prolonged hypotension during operation and new onset of pneumothorax, we think that intraoperative prolonged hypotension leads to the spinal cord ischemia which may cause neurological deterioration of paraplegia. Maintaining hemodynamic stability during spinal surgery is very important.

Clinical effect analysis of laminectomy alone and laminectomy with instrumentation in the treatment of TOLF

Background

To explore the clinical effect of laminectomy alone and laminectomy with instrumentation in the treatment of TOLF.

Methods

A retrospective study was conducted on the clinical data of 142 patients with TOLF and laminectomy who underwent spine surgery at XXX Medical University from January 2003 to January 2018. According to whether the laminectomy was combined with instrumentation, the patients were divided into two groups: group A (laminectomy alone (LA), n = 77) and group B (laminectomy with instrumentation (LI), n = 65). Comparisons of possible influencing factors of demographic variables and operation-related variables were carried out between the two groups. In this study, the clinical effects of LA and LI in the treatment of TOLF were discussed. Thus, we explored the clinical effect of LA and LI in the treatment of TOLF.

Results

In terms of demographics, there was a statistically significant difference in BMI between group A and group B (P < 0.05). The differences in age, sex, smoking, drinking, heart disease, hypertension and diabetes were not statistically significant (P > 0.05). In terms of preoperative symptoms, there was a significant difference in gait disturbance, pain in the LE, and urination disorder between group A and group B (P < 0.05), but there was no significant difference in other variables between the two groups (P > 0.05). In terms of operation-related variables, there was a significant difference in the preoperative duration of symptoms, intramedullary signal change on MRI, dural ossification, residual rate of cross-sectional spinal canal area on CT, shape on the sagittal MRI, operation time, pre-mJOA, post-mJOA at 1 year, and leakage of cerebrospinal fluid between group A and group B (P < 0.05), but there was no significant difference in other variables between the two groups (P > 0.05). The preoperative average JOA score of group A was 6.37 and that of group B was 5.19. In group A, the average JOA score at 6 months, 1 year and 2 years after surgery was 7.87, 8.23 and 8.26, respectively, and the average JOA score improvement rate was 32.79 %, 38.32 and 38.53 %, respectively. In group B, the average JOA score at 6 months, 1 year and 2 years after surgery was 7.74, 8.15 and 8.29, respectively, and the average JOA score improvement rate was 39.15 %, 46.86 and 47.12 %, respectively.

Conclusions

Currently, there is no consensus on whether instrumentation is needed after laminectomy for TOLF. We found that for patients with a long duration of gait disturbance, urination disorder, preoperative duration of symptoms, intramedullary signal change on MRI, dural ossification, residual rate of cross-sectional spinal canal area on CT less than 60 %, and shape on the sagittal MRI being beak and low, pre-mJOA had better clinical effects after LI as compared to those after LA, and the incidence of perioperative complications was lower.

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.

A systematic review of surgical procedures on thoracic myelopathy

Purpose

The surgical treatment of thoracic myelopathy is still controversial and also a challenge for spine surgeons. Therefore, the objective of this study was to review the related literature on the surgical treatment of thoracic myelopathy and try to define treatment guidelines for spine surgeons on thoracic myelopathy.

Methods

Relevant literatures were searched based on the PubMed, EMBASE, and Cochrane Library between January 2008 and December 2018. Some data on the characteristics of patients were extracted, including number of patients, mean age, surgical procedures, blood loss, complications, and pre-/post-operation modified JOA score. Recovery rate was used to assess the effect of surgery outcome, and the safety was evaluated by blood loss and incidence of complications.

Results

Thirty-five studies met the inclusion criteria and were retrieved. A total of 2183 patients were included in our systematic review, with the average age of 55.2 years. There were 69.8% patients diagnosed as ossification of ligamentum flavum (OLF), 20.0% as ossification of posterior longitudinal ligament (OPLL), 9.3% as disk herniation (DH), and 0.9% as others including diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS). The volume of blood loss was more in the treatment of circumferential decompression (CD) than posterior decompression (PD), and the incidence of complications was higher in CD (P < 0.05). The volume of blood loss in minimally invasive surgery (MIS) was lowest and the incidence of complications was 19.2%. Post-operation recovery rate was 0.49 in PD, 0.35 in CD, and 0.29 in MIS while the recovery rate was 0.54 in PD, 0.55 in CD, and 0.49 in MIS at the last follow-up. When focusing on the OLF specifically, incidence of complications in PD was much lower than CD, with less blood loss and higher recovery rate. Focusing on the OPLL specifically, incidence of complications in PD was much lower than CD, with less blood loss while there was no statistical difference in recovery rate between these two methods.

Conclusions

This systematic review showed that posterior decompression for thoracic myelopathy is safer and better than circumferential decompression according to the complication rate and surgical outcome. And we should also consider the location of compression before the operation.

Outcomes of Surgery for Thoracic Myelopathy Owing to Thoracic Ossification of The Ligamentum Flavum in a Nationwide Multicenter Prospectively Collected Study in 223 Patients: Is Instrumented Fusion Necessary?

STUDY DESIGN

Prospectively collected, multicenter, nationwide study.

OBJECTIVE

The aim of this study was to investigate recent surgical methods and trends, outcomes, and perioperative complications in surgery for thoracic ossification of the ligamentum flavum (T-OLF).

SUMMARY OF BACKGROUND DATA

A prospective multicenter study of surgical complications and risk factors for T-OLF has not been performed, and previous multicenter retrospective studies have lacked details for these items.

METHODS

Surgical methods, pre- and postoperative thoracic myelopathy (Japanese Orthopedic Association [JOA] score), symptoms, and intraoperative neurophysiological monitoring were investigated prospectively in 223 cases. Differences in these factors between fusion and nonfusion procedures for T-OLF were examined. The minimum follow-up period was 2 years after surgery RESULTS.: The mean JOA score was 6.2 points preoperatively, and 7.9, 8.2, and 8.2 points at 6 months, 1, and 2 year postoperatively, giving mean recovery rates of 35.0%, 40.9%, and 41.4% respectively. Posterior decompression and fusion with instrumentation was performed in 109 cases (48.9%). There were 45 perioperative complications in 30 cases (13.5%), with aggravation of motor disturbance in the lower extremities being most common (4.0%, n = 9). Patients treated with fusion had a significantly higher BMI, rate of gait disturbance, ossification occupation rate of OLF at computed tomography, and intramedullary high intensity area at magnetic resonance imaging (P < 0.01). The preoperative JOA score was lower (P < 0.05) and the JOA recovery rate at 1 year after surgery was significantly higher in cases treated without fusion (44.9% vs. 37.1%, P < 0.05).

CONCLUSION

The high rate of surgery with instrumentation of 48.9% reflects the current major trend toward posterior instrumented fusion surgery for T-OLF. Fusion surgery with instrumentation may be appropriate for patients with severe OLF and preoperative myelopathy. A further prospective study of long-term outcomes is required with a focus on optimal surgical timing and the surgical procedure for T-OPLL.

LEVEL OF EVIDENCE

3.

A rare cause of neurological deterioration to complete paraplegia after surgery for thoracic myelopathy: a case report

Introduction

Progressive deterioration of neurological status post-thoracic myelopathy surgery after a clinically stable period is rare and can pose a diagnostic dilemma. We present our experience with such a case where all known etiologies were ruled out and the cause of deterioration could not be conclusively identified. The course was found to be similar to sub-acute post-traumatic ascending myelopathy (SPAM). However, the condition has only been described for traumatic injuries so far.

Case presentation

Our patient presented a history of back pain and associated gait instability for one and a half months. There was no history of trauma. Investigations suggested an Anderson-like lesion at T11-T12 with cord edema at the same level suggestive of instability. She underwent posterior stabilization T9 to L2 and laminectomy of T11 as well as T12 under neuromonitoring. The postoperative sequence of events included an episode of pyrexia on the fifth day of surgery, neurological deterioration from the seventh day of surgery proceeding to complete paraplegia by the fourteenth day, no response to steroid treatment and no signs of recovery till two years post surgery. MRI findings were suggestive of SPAM, and there was no evidence of infection.

Discussion

Ascending myelopathy is a potential but rare cause of delayed deterioration in neurological status after surgical intervention. MRI findings of cord edema extending more than four levels above the involved segments is a characteristic finding of the condition. Ascending myelopathy may lead to complete cord injury. The precise cause of the condition is unknown and prognosis remains poor.

Percutaneous full endoscopic posterior decompression of thoracic myelopathy caused by ossification of the ligamentum flavum

PURPOSE

Ossification of ligamentum flavum (OLF) is the leading cause of progressive thoracic myelopathy (TM) in East Asian countries. Surgical decompression is the general treatment for TM. This study investigated the application of percutaneous full endoscopic posterior decompression (PEPD) for the treatment of thoracic OLF.

METHODS

Eighteen patients with TM were treated by PEPD under local anaesthesia. Patients had an average age of 59.1 years and single-level lesions mostly at the lower thoracic vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. The pre- and postoperative neurological statuses were evaluated using the American Spinal Injury Association (ASIA) sensory and motor score, modified Japanese Orthopaedic Association (mJOA) score and Frankel grade.

RESULTS

OLF for all patients was classed as lateral, extended, and enlarged types without comma and tram track signs. Decompression was completed, and a dome-shaped laminotomy was performed through limited laminectomy and flavectomy. Dural tears in 2 patients were the only observed complication. The average score of ASIA sensory and motor, mJOA, as well as the Frankel grade improved significantly after surgery at an average follow-up time of 17.4 months. The average recovery rate (RR) was 47.5% as calculated from the mJOA scores. According to RR, 10 cases were classified as good, 4 cases fair, and 4 cases unchanged.

CONCLUSIONS

For patients with thoracic OLF at a single level and lateral, extended, and enlarged types without comma and tram track signs, it is safe and reliable to perform PEPD, which has satisfactory clinical results. These slides can be retrieved under Electronic Supplementary Material.

Progress in Intraoperative Neurophysiological Monitoring for the Surgical Treatment of Thoracic Spinal Stenosis

Thoracic spinal stenosis (TSS) is a group of clinical syndromes caused by thoracic spinal cord compression, which always results in severe clinical complications. The incidence of TSS is relatively low compared with lumbar spinal stenosis, while the incidence of spinal cord injury during thoracic decompression is relatively high. The reported incidence of neurological deficits after thoracic decompression reached 13.9%. Intraoperative neurophysiological monitoring (IONM) can timely provide information regarding the function status of the spinal cord, and help surgeons with appropriate performance during operation. This article illustrates the theoretical basis of applying IONM in thoracic decompression surgery, and elaborates on the relationship between signal changes in IONM and postoperative neurological function recovery of the spinal cord. It also introduces updated information in multimodality IONM, the factors influencing evoked potentials, and remedial measures to improve the prognosis.

Predictive factors for neurological deterioration after surgical decompression for thoracic ossified yellow ligament

PURPOSE

To investigate the rate and predictive factors of post-operative neurological deterioration in ossified yellow ligament (OYL) surgery.

METHODS

A retrospective review was conducted for all patients with thoracic OYL causing myelopathy requiring surgical decompression from January 1998 to December 2012. Clinical parameters under study included clinical presentation, distribution of OYL, pre-operative walking score, pre- and post-operative neurological status, status of intra-operative neurophysiological monitoring, and modified Japanese Orthopaedic Association (mJOA) score. Any complications were also recorded. All outcomes were measured at post-operative 1 week and at 2 years.

RESULTS

A total of 26 patients were included in this study. Most patients (92.3%) had Frankel grade D pre-operatively. The rate of neurological deterioration was 15.4% and was correlated with the presence of dural tear, extra-dural hematoma and spinal cord injury. Pre-operative walking score was prognostic of patients' walking ability in the post-operative period. Intra-operative monitoring of Somatosensory Evoked Potentials (SSEP) was found to be useful for monitoring spinal cord injury in OYL surgery, with a positive predictive value of 100% and a negative predictive value of 92.3%. The false negative rate of a SSEP signal drop was only 7.7% CONCLUSIONS: This is the first study exploring risk factors for post-operative neurological deterioration after surgery for thoracic OYL. The rate of neurological deficit is not small and prognostic factors for poor outcome include poor pre-operative walking score, presence of intra-operative dural tear, extra-dural hematoma and spinal cord injury, and intra-operative drop of SSEP signal.