A Novel Posterior Trench Approach Involving Percutaneous Endoscopic Cervical Discectomy for Central Cervical Intervertebral Disc Herniation

Outcomes and Complications Associated With the Learning Curve for Endoscopic Cervical Foraminotomy: A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The objective of this study is to examine the impact of the learning curve for endoscopic cervical foraminotomy for clinical outcomes and patient safety.

SUMMARY OF BACKGROUND DATA

Endoscopic cervical foraminotomy is a minimally invasive surgical technique emerging in the literature for surgical management of cervical radiculopathy without the use of open incision. The adoption of endoscopic cervical foraminotomy may be hindered by the learning curve, although no review and meta-analysis exists to date on the topic.

MATERIALS AND METHODS

A systematic review and meta-analysis was performed using PubMed, CINAHL, and MEDLINE from database inception until July 11, 2023. Inclusion criteria were articles that examined endoscopic cervical foraminotomy, reported outcomes, and/or complications for endoscopic cervical spine surgery relevant to the learning curve and had full-text. A random effects meta-analysis was performed for outcomes and complications.

RESULTS

A total of three articles (n=203 patients) were included from 792 articles initially retrieved. The learning curves from four surgeons were examined with a FWM 21 procedures until the competency phase. There was no significant difference in the postoperative hospitalization length ( P =0.669), postoperative recovery room time ( P =0.415), intraoperative blood loss ( P =0.064), and total complication rates (10.9% vs . 1.2%, P =0.139) between endoscopic cervical foraminotomy procedures performed in the learning phase as compared with the competency phase of the learning curve. There was a significant decrease in operative time from the learning phase to the competency phase ( P =0.005).

CONCLUSION

Competency was achieved on the learning curve for endoscopic cervical foraminotomy after about 21 procedures. There is no significant difference in postoperative hospitalization time, postoperative recovery room time, intraoperative blood loss, and complication rates between the learning phase and the competency phase of the learning curve for endoscopic cervical foraminotomy, noting the relatively small sample size of this study that may underpower this finding.

Percutaneous Endoscopic Posterior Lateral Approach for the Treatment of Central Cervical Disc Herniation

BACKGROUND

To design percutaneous endoscopic surgery via a posterolateral approach for the treatment of central cervical disc herniation.

METHODS

From October 2019 to October 2020, 12 consecutive patients with central cervical disc herniation underwent percutaneous endoscopic posterior lateral cervical surgery. The imaging examination (dynamic X-ray, computed tomography, and magnetic resonance imaging of the cervical spine) was conducted after the operation. Visual analog scale score and the modified Japanese Orthopaedic Association score was performed before and after the operation.

RESULTS

Twelve patients (6 men and 6 women; mean age 52.08 ± 9.3 years) were included, and the average operation time was 105.00 ± 10.55 minutes. Postoperative computed tomography and magnetic resonance imaging results showed that the treatment segment of all patients was prominent, the cervical intervertebral disc was completely removed, the cervical spinal cord was fully decompressed, and there were no cases of infection, cerebrospinal fluid leakage or neurological complications. The average follow-up time after the operation was 22.83 ± 3.13 months. One year after the operation, there was no cervical instability in the X-ray examination of cervical flexion and extension position. Preoperative visual analog scale score and the modified Japanese Orthopaedic Association score were significantly improved at the last follow-up.

CONCLUSION

Percutaneous endoscopic posterior lateral cervical discectomy provides a new surgical method for the endoscopic treatment of central cervical disc herniation. This treatment has a better surgical field and easier operation, which can remove the protruding cervical disc under the endoscope and make sure that the cervical spinal cord is fully decompressed. The clinical effect is satisfactory. A small amount of pedicle resection will not cause cervical instability.

Surgical Technique of Central and Over-the-Top Full-Endoscopic Decompression of the Cervical Spine: A Technical Note

Endoscopic surgery of the cervical spine is constantly evolving and the spectrum of its indications has expanded in recent decades. Full-endoscopic techniques have standardized the procedures for posterior and anterior access. The full-endoscopic approach was developed to treat degenerative diseases with the least possible invasion and without causing instability of the cervical spine. The posterior full-endoscopic approach is indicated for the treatment of diseases of the lateral part of the vertebral segment, such as herniations and stenoses of the lateral recess and vertebral foramen. There has been little discussion of this approach to the treatment of central stenosis of the cervical spine. This technical note describes a step-by-step surgical technique for central and over-the-top full-endoscopic decompression in the cervical spine, using a 3.7 mm working channel endoscope. This technique has already been shown to be effective in a recent case series with a 4.7 mm working channel endoscope, and may represent a new treatment option for central or bilateral lateral recess stenosis. There is also the possibility of a bilateral full-endoscopic approach, but this may be associated with greater muscle damage and a longer operative time. Case series and comparative studies should be encouraged to confirm the safety and utility of this technique.

Complications of Cervical Endoscopic Spinal Surgery: A Systematic Review and Narrative Analysis

BACKGROUND

There are no systematic evidence-based medical data on the complications of endoscopic cervical spinal surgery. This narrative analysis compiled data from various studies that examined endoscopic complications, such as cervical disc herniation and foraminal stenosis. This study aimed to investigate the efficacy and safety of endoscopic surgery in cervical radiculopathy.

METHODS

We searched the PubMed/MEDLINE databases to identify articles on endoscopic spinal surgery, and keywords were set as "endoscopic cervical spinal surgery", "endoscopic cervical discectomy", "endoscopic cervical foraminotomy", and "percutaneous endoscopic cervical discectomy". We analyzed the evidence level and classified the prescribed complications according to the literature. Endoscopic cervical surgery was divided into three categories: full endoscopic anterior, endoscopic posterior, and unilateral biportal approaches. We excluded duplicate publications, studies without full text, studies without complications or incomplete information, and studies that did not provide the necessary data for extraction, animal experiments, or reviews.

RESULTS

Difficulties in swallowing, hematoma, and hoarseness are common complications associated with the anterior cervical approach. In contrast, complications of the posterior approach include nerve root injury, hematoma, and dysesthesia. However, endoscopic cervical spinal surgery, including the full endoscopic anterior, posterior, and unilateral biportal approaches, is a safe and effective treatment for cervical radiculopathy.

CONCLUSIONS

Complications of full endoscopic cervical spinal surgery differ significantly depending on the anterior and posterior approaches. In the anterior approach, swallowing difficulty, recurrent disc, hematoma, and dysphonia are the common complications. In contrast, transient dysesthesia, dural tears, upper limb motor deficits, and persistent arm pain are commonly reported with the posterior approach.

Clinical efficacy of posterior endoscopic cervical modified trench technique in the treatment of cervical spondylotic myelopathy: A retrospective study

To investigate the clinical efficacy of the posterior endoscopic cervical modified trench technique in the treatment of cervical spondylotic myelopathy (CSM). This retrospective study included 9 patients with single-segment CSM, who were treated with posterior endoscopic cervical modified trench technique. Related clinical data, the visual analog scale, Japanese Orthopedic Association (JOA) ratings, JOA improvement rate, the minimum sagittal diameter of the spinal canal, and surgical complications were recorded. There were 5 men and 4 females, with an average age of 60.44 ± 16.49 years. Without any significant side effects like paralysis, vascular damage, or cerebrospinal fluid leaking, all surgeries were successfully completed. One year's worth of follow-up with patients lasted for 8.56 ± 3.68 months. When compared to before surgery, the postoperative visual analog scale ratings, JOA scores, and minimum sagittal diameter of the spinal canal value all showed a substantial improvement (P < .01). At the most recent follow-up, 2 patients had a JOA improvement rate of >75%, 6 patients had a JOA improvement rate of 74 to 50%, 1 patient had a JOA improvement rate of 49 to 25%, and none had a JOA improvement rate of <25%. The JOA improvement rate was above 90% for overall excellent and good ratings. In our study, the ventral epidural space may be maneuvered more easily and instrument-induced nerve discomfort is decreased when using the posterior endoscopic cervical modified trench approach with posterior endoscopy. The short-term clinical effect of the posterior endoscopic cervical modified trench technique for CSM is satisfactory.

Complications and Management of Endoscopic Spinal Surgery

In the past, the use of endoscopic spine surgery was limited to intervertebral discectomy; however, it has recently become possible to treat various spinal degenerative diseases, such as spinal stenosis and foraminal stenosis, and the treatment range has also expanded from the lumbar spine to the cervical and thoracic regions. However, as endoscopic spine surgery develops and its indications widen, more diverse and advanced surgical techniques are being introduced, and the complications of endoscopic spine surgery are also increasing accordingly. We searched the PubMed/MEDLINE databases to identify articles on endoscopic spinal surgery, and key words were set as “endoscopic spinal surgery,” “endoscopic cervical foramoinotomy,” “PECD,” “percutaneous transforaminal discectomy,” “percutaneous endoscopic interlaminar discectomy,” “PELD,” “PETD,” “PEID,” “YESS” and “TESSYS.” We analyzed the evidence level and classified the prescribed complications according to the literature. Endoscopic lumbar surgery was divided into full endoscopic interlaminar and transforaminal approaches and a unilateral biportal approach. We performed a comprehensive review of available literature on complications of endoscopic spinal surgery. This study particularly focused on the prevention of complications. Regardless of the surgical methods, the most common complications related to endoscopic spinal surgery include dural tears and perioperative hematoma. transient dysesthesia, nerve root injury and recurrence. However, Endoscopic spinal surgery, including full endoscopic transforaminal and interlaminar and unilateral biportal approaches, is a safe and effective a treatment for lumbar as well as cervical and thoracic spinal diseases such as disc herniation, lumbar spinal stenosis, foraminal stenosis and recurrent disc herniation.

Morphology of Herniated Disc as a Predictor for Outcomes of Posterior Percutaneous Full-endoscopic Cervical Discectomy in Treating Cervical Spondylotic Radiculopathy

Objective

To quantitively characterize the morphology of cervical disc herniation (CDH) causing cervical spondylotic radiculopathy (CSR) and investigate whether the morphological features of CDH are associated with clinical outcomes in CSR patients treated by posterior percutaneous full‐endoscopic cervical discectomy (PPECD).

Methods

This is a single‐center retrospective study. Eighty‐seven PPECD‐treated patients meeting the inclusion criteria were included between May 2017 and May 2019. Based on preoperative T2‐weighted magnetic resonance imaging (MRI), we designed and measured six morphological parameters of CDH for all patients to reflect its relative position to cervical spinal cord and protruding degree: DC‐SC distance from the center of disc (DC) and the center of spinal cord (SC); DC‐DP distance from the center of cervical disc (DC) to the peak of herniation (DP); internal diameter of the disc; axial length of CDH; central angle of CDH formed by central axes of CDH and spinal cord; the modified index of CDH. We recorded general information, neck disability index (NDI) scores, visual analog scale (VAS) scores of neck and arm of all patients preoperatively and postoperatively at 1‐year follow‐up. The association of preoperative general variables and morphological parameters with clinical outcomes were explored by utilizing logistic regression and receiver operating characteristic curve (ROC) analysis.

Results

The preoperative neck‐VAS, arm‐VAS, and NDI were significantly decreased after PPECD and remained at a low value at follow‐up. In regards to the morphological parameters of CDH, the mean value of DC‐SC distance, DC‐DP distance, internal diameter of the disc, axial length of CDH, central angle of CDH, and modified index of CDH were 1.61 ± 0.30 cm, 1.66 ± 0.32cm, 1.04 ± 0.21 cm, 0.63 ± 0.19cm, 39.38° ± 11.94°, and 0.39 ± 0.24, respectively. For patients grouped by difference in the recovery rate of NDI and arm‐VAS (excellent improved group, EI; and limited improved group, LI), there were no differences in the age, gender, surgical segments, and morphological parameters, except for the central angle of CDH. According to binary logistic regression analysis, only the preoperative central angle of CDH was significantly associated with postoperative NDI recovery (odds ratio: 0.873; 95% confidence interval: 0.819–0.931, P = 0.002). ROC analysis showed the optimal cut‐off value of the central angle of CDH for predicting the postoperative improvement of functional outcomes is 33.788°.

Conclusion

Preoperative morphology of CDH is related to the outcomes of CSR patients after PPECD. Patients with a large central angle of CDH (>33.788°) have more likelihood of ameliorating neurological symptoms of CSR. There is the potential to select the central angle of CDH as a predictor for outcomes of PPECD in treating CSR.

[Posterior percutaneous endoscopy via vertical anchor technique combined with trench technique for single-segmental central cervical disc herniation]

Objective

To investigate the clinical feasibility, safety, and effectiveness of posterior percutaneous endoscopy via vertical anchor technique combined with trench technique for single-segmental central cervical disc herniation.

Methods

Between July 2017 and August 2019, 13 patients with the single-segmental central cervical disc herniation suffering from various neurologic deficits were treated with posterior percutaneous endoscopy via vertical anchor technique combined with trench technique. There were 6 males and 7 females with an average age of 50.5 years (range, 43-64 years). Disease duration ranged from 3 to 17 months (mean, 9.2 months). The clinical symptoms of 5 cases were mainly neck pain, radiculopathy, and numbness in upper limbs, and the visual analogue scale (VAS) score was 6.60±0.55. The clinical symptoms of 8 cases were myelopathy including upper extremities numbness, weakness, and trouble walking, and the modified Japanese Orthopedic Association (mJOA) score was 12.75±0.71. The surgery-related complications, operation time, and intraoperative blood loss were recorded, and the results of clinical symptoms were measured by VAS scores and mJOA scores.

Results

All procedures were completed successfully, no severe complications such as dural tears or cerebrospinal fluid leakage occurred. The operation time ranged from 83 to 164 minutes (mean, 101.2 minutes). The intraoperative blood loss was 25-50 mL (mean, 33.1 mL). After operation, 12 of 13 cases were followed up 10-24 months (mean, 17.6 months). The VAS scores of patients with preoperative pain symptoms were 2.40±0.55 on the first day after operation and 1.80±0.45 at last follow-up, which were significantly lower than those before operation ( P<0.05). The mJOA scores of patients with the symptoms of spinal cord injury were 12.63±0.52 on the first day after operation and 14.29±0.95 at last follow-up, and the score at last follow-up was significantly higher than that before operation ( P<0.05). Acute extremities weakness occurred for the postoperative hematoma formation in 1 case (disc herniation at C _{4, 5}) presented with myelopathy preoperatively, and muscle strength was recovered after the clearance of hematoma and spinal cord decompression under percutaneous endoscopy.

Conclusion

Posterior percutaneous endoscopy via vertical anchor technique and trench technique for single-segmental central cervical disc herniation was clinical feasible, safe, and effective, and could be an alternative approach to the treatment of central cervical disc herniation.

Posterior Endoscopic Cervical Decompression: Review and Technical Note

Endoscopic spine surgery for the treatment of degenerative spinal diseases from lumbar to cervical spine has accelerated over the past 2 decades. Posterior endoscopic cervical discectomy (PECD) has been described as a safe, effective, and minimally invasive procedure for cervical radiculopathy or even part of the myelopathy. This procedure also has been validated with comparable outcomes to open and microscopic surgery. Radiculopathy due to foraminal disc herniation or foraminal stenosis should be the optimum indications of this procedure. Intraoperative 3-dimensional navigation can help surgeons to get quick and great quality guidance for endoscopic surgeons. In this review, we will focus on the technical details and evidence-based results of PECD which is a promising procedure for cervical radiculopathy with the advantages of a minimally invasive method.

[Clinical study of single-level cervical disc herniation treated by full-endoscopic decompression via anterior transcorporeal approach]

Objective

To investigate the clinical feasibility of full-endoscopic decompression for the treatment of single-level cervical disc herniation via anterior transcorporeal approach.

Methods

According to the inclusion and exclusion criteria, 21 patients with cervical disc herniation who received full-endoscopic decompression via anterior transcorporeal approach between September 2014 and March 2016 were retrospectively analyzed. There were 12 males and 9 females with an age ranged from 32 to 65 years, with an average of 48.5 years. The duration of symptoms ranged from 6 to 18 weeks, with an average of 10.5 weeks. According to the Nurick grading of spinal cord symptoms, there were 2 cases with grade 1, 7 cases with grade 2, and 12 cases with grade 3. Operative segment was C _{3, 4} in 2 cases, C _{4, 5} in 8 cases, C _{5, 6} in 9 cases, and C _{6, 7} in 2 cases. The operation time and related complications were recorded. The central vertical height of the vertebral body and the diseased segment space were measured on the cervical X-ray film. The neck and shoulder pain were evaluated by visual analogue scale (VAS) score; Japanese Orthopaedic Association (JOA) score was used to evaluate the improvement of neurological function in patients. The MRI of cervical spine was reexamined at 3 months after operation, and the CT of cervical spine was reexamined at 12 months after operation. The decompression of spinal cord and the healing of bone canal in the vertebral body were further evaluated.

Results

Full-endoscopic decompression via anterior transcorporeal approach were achieved at all 21 patients. The operation time was 85-135 minutes, with an average of 96.5 minutes. All patients were followed up 24-27 months, with an average of 24.5 months. There was no complication such as residual nucleus pulposus, spinal cord injury, large esophageal vessels injury, pleural effusion, endplate collapse, intraspinal hematoma, cervical spine instability, protrusion of disc in the same segment, or kyphosis. Both VAS scores of neck and shoulder pain and JOA scores were significantly improved at 12 months after operation ( P<0.05). At 3 months after operation, it was confirmed by the cervical MRI that neural decompression was sufficient and the abnormal signal was also degraded in the patients with intramedullary high signal at T2-weighted image. The cervical CT showed that bone healing were achieved in the surgical vertebral bodies of all patients at 12 months after operation. At 24 months after operation, the central vertical height of the diseased segment space significantly decreased compared with preoperative one ( t=2.043, P=0.035); but there was no significant difference in the central vertical height of the vertebral body between pre- and post-operation ( t=0.881, P=0.421).

Conclusion

Full-endoscopic decompression via anterior transcorporeal approach, integrating the advantages of the endoscopic surgery and the transcorporeal approach, provide an ideal and thorough decompression of the ventral spinal cord with satisfactory clinical and radiographic results.

Posterior Unlocking of Facet Joints Under Endoscopy Followed by Anterior Decompression, Reduction, and Fixation of Old Subaxial Cervical Facet Dislocations: A Technical Note

OBJECTIVE

Besides the facet joints interlocking, the fibrous tissue or bony callus around the dislocated segments make the reduction for this kind of old injury to be more challenging and different from that of acute injuries. This study is aimed to present 4 cases of old subaxial cervical facet dislocations (SCFD) that were successfully treated with posterior unlocking under endoscopy followed by anterior decompression, reduction, and fixation.

METHODS

Between January 2017 and December 2017, 4 patients with old SCFD who underwent posterior unlocking of facet joints under endoscopy followed by anterior decompression, reduction, and fixation were enrolled. A cervical collar was prescribed for 4 weeks postoperatively. Postoperative follow-up evaluations were conducted at 2, 6, and 12 months, including neck visual analogue scale score and neck disability index, radiography, and computed tomography.

RESULTS

The operative time averaged 145 minutes (range, 130-155 minutes). No deterioration of neural function, major vessel rupture, or iatrogenic injury to esophagus occurred. Intraoperative blood loss averaged 45 mL (range, 40-50 mL). Hospital stay for all patients was only 4 days. The neck visual analogue scale score and neck disability index were improved at the final follow-up, and interbody fusion was satisfactory without any radiologic sign of instability or internal failure.

CONCLUSIONS

For patients with old SCFD, the unlocking of facet joints via the posterior approach under endoscopy followed by anterior decompression, reduction, and fixation is an alternative technique.