Anterior cervical discectomy and interbody fusion by endoscopic approach: a preliminary report

Anterior Endoscopic Cervical Discectomy: Surgical Technique and Literature Review

The conventional surgical technique for radiculopathy with cervical disc herniation (CDH) is anterior cervical discectomy and fusion, with a good clinical outcome and fusion rate. However, significant perioperative morbidity related to extensive surgical exposure has been reported. Therefore, anterior endoscopic cervical discectomy (AECD) using a working channel endoscope has been developed to reduce surgical complications and tissue damage. The objective of this study was to describe a cutting-edge technique for AECD of soft CDH. The primary indication is cervical radiculopathy with or without axial neck pain due to soft CDH. The surgical procedure consists of 2 parts: (1) a safe anterior percutaneous approach under fluoroscopic control and (2) selective endoscopic discectomy and foraminal decompression using specialized mechanical tools under endoscopic visualization. The clinical outcomes are comparable to those of conventional surgery and show the benefits of minimally invasive spine procedure. Perioperative data revealed typical minimalism, including reduced muscle damage, blood loss, operative time, and recovery time. With technical advancements in surgical instruments and optics, AECD will become more practical and safer. AECD is effective in selected CDH cases with cervical radiculopathy. However, high-quality clinical studies are needed to verify the effectiveness of this endoscopic cervical spinal procedure.

Management of Cervical Spondylotic Radiculopathy: A Systematic review

OBJECTIVE

(1) To evaluate the effects of surgery and conservative treatments for cervical spondylotic radiculopathy and (2) provide reference for choosing the time and method of treatment.

METHODS

A literature search was performed using PubMed, EMbase, The Cochrane Library, Web of Science, and ClinicalTrials from inception to September 2021. Randomized controlled trials (RCTs) on the use of surgery or conservative Treatments in Cervical Spondylotic Radiculopathy (CSR) were selected. The primary outcomes were the neck and arm visual analog scale (VAS) and Neck Disability Index (NDI). Secondary outcomes included active range of cervical motion (ROM) and Mental Health. Two reviewers proceeded study selection and quality assessment.

RESULTS

A total of 6 studies, which comprised a total of 464 participants were included in the final meta-analysis. Compared with conservative treatment, surgical treatment was more effective in lowering Neck-VAS (<3 m: MD = -29.44, 95% CI = (-41.62,-17.27), P < .00001; 3-6 M: MD = -20.97, 95% CI = (-26.36,-15.57), P < .00001; 6 M: MD = -13.40, 95% CI = (-19.39, -7.41), P<.0001; 12 M: MD=-15.53, 95% CI=(-28.38, -2.68), P=.02), Arm-VAS(<3 m: MD = -33.52, 95% CI = (-39.89, -27.16), P < .00001; 3-6 M: MD = -20.97, 95% CI = (-26.36, -15.57), P < .00001; 6 M: MD = -17.52, 95% CI=(-23.94, -11.11), P < .0001; 12 M: MD = -21.91, 95% CI=(-27.09, -16.72), P < .00001) and NDI (<3 m: MD = -8.89, 95% CI = (-11.17, -6.61), P < .00001; 6 M: MD = -5.14, 95% CI = (-7.60, -2.69), P < .0001). No significant difference was observed in NDI at 12-month time point (MD = -5.17, 95% CI = (-12.33, 2.00), P = .16), ROM(MD = 2.91, 95% CI = (-4.51, 10.33), P = .77) and Mental Health (MD = .05, 95% CI=(-.24, .33), P = .74).

CONCLUSION

The 6 included studies that had low risk of bias, providing high-quality evidence for the surgical efficacy of CSR. The evidence indicates that surgical treatment is better than conservative treatment in terms of VAS score and NDI score, and superior to conservative treatment in less than one year. There was no evidence of a difference between surgical and conservative care in ROM and mental health. A small sample study with a follow-up of 5 to 8 years showed that surgical treatment was still better than conservative treatment, but the sample size was small and the results should be carefully interpreted.Compared with conservative treatment, surgical treatment had a faster onset of response, especially in pain relief, but did not have a significant advantage in range of motion or NDI. This seems to mean that for patients with severe or even unbearable pain, the benefits of surgery as soon as possible will be significant. Although it is not clear whether the short-term risks of surgery are outweighed by the long-term benefits, rapid pain relief is necessary. Conservative treatment (including medical exercise therapy, mechanical cervical tractions, transcutaneous electrical nerve stimulation, pain management education, and cervical collar) once or twice a week for 3 months is beneficial in the long term and avoids the risks of surgery. In consideration of the good natural history of CSR and the relatively good outcome of conservative treatment (although symptom relief is slow), we think that surgery is not necessary for patients who do not need rapid pain relief.

Current Status and research hotspots in the field of full endoscopic spine surgery: A bibliometric analysis

Purpose

We aimed to comprehensively analyze the current status, hotspots, and trends in full endoscopic spine surgery (FESS) research using bibliometric analysis and knowledge domain mapping.

Methods

The Web of Science database was used to screen FESS-related articles published between January 1, 1993 and June 10, 2022. The evaluation involved the following criteria: total number of articles; H-index; and contributions from countries/regions, institutions, journals, and authors.

Results

A total of 1,064 articles were included. Since 2016, there have been a significant number of publications in the field of FESS. The country/region contributing the largest number of articles was China (37.8%), followed by South Korea (24%), the United States (16.1%), Japan (5.7%), and Germany (5.1%). South Korea (35) had the highest H-index, followed by the United States (27), China (22), Japan (21), and Germany (20). World Neurosurgery (15.7%) published the largest number of FESS-related articles. However, among the top 10 most cited articles, six were published in Spine. The author who contributed the most was S.H. Lee (5.4%), and the largest number of contributions in this field originated from Wooridul Spine Hospital (South Korea; 6.1%). Notably, six of the 10 most published authors in this field were from South Korea. Of the top five productive institutions, three were from South Korea. The keywords with the strongest citation bursts in the field of FESS were “lumbar spine,” “discectomy,” “interlaminar,” “surgical technique,” “follow-up,” “excision,” “thoracic spine,” and “endoscopic surgery.” The 10 clusters generated in this study were: “endoscopic discectomy” (#0), “thoracic myelopathy” (#1), “recurrent lumbar disc herniation” (#2), “low back pain” (#3), “cervical vertebrae” (#4), “lumbar spinal stenosis” (#5), “transforaminal lumbar interbody fusion” (#6), “radiation exposure” (#7), “management” (#8), and “lumbar spine” (#9).

Conclusion

Global research on FESS is mostly concentrated in a few countries/regions and authors. South Korea has made the largest contribution to the field of FESS. Based on the most cited keyword bursts and clusters, the focus of FESS research was found to include its indications, management, and applications.

Learning curve of percutaneous endoscopic transforaminal lumbar discectomy by a single surgeon

To evaluate the learning curve of percutaneous endoscopic transforaminal lumbar discectomy (PETLD) from the novice stage to the proficient stage, we performed retrospective study for patients with lumbar disc herniation who underwent PETLD performed by a single surgeon and evaluated the surgeon's learning curve and the effect of surgical proficiency on outcomes.A total of 48 patients who underwent PETLD at the lower lumbar level (L3-S1) with a minimum 1-year follow-up were enrolled. The learning curve of the surgeon was assessed using cumulative study of operation time and linear regression analyses to reveal the correlation between operation time and case series number.Because the cutoff of familiarity was 25 cases according to the cumulative study of operation time, the patients were allocated into two groups: early group (n = 25) and late group (n = 23). The clinical, surgical, and radiological outcomes were retrospectively evaluated and compared between the two groups.According to linear regression analyses, the operation time was obtained using the following formula: operation time (minutes) = 69.925-(0.503 × [case number]) (P < .001).As expected, the operation time was significantly different between the two groups (mean 66.00 ± 11.37 min in the early group vs 50.43 ± 7.52 min in the late group, P < .001). No differences were found between the two groups in demographic data and baseline characteristics. Almost all clinical outcomes (including pain improvement and patient satisfaction), surgical outcomes (including failure, recurrence, and additional procedure rates), and radiological outcomes (including change of disc height and sagittal angles) did not differ between the two groups.However, the late group demonstrated a more favorable postoperative volume index of the remnant disc (362.91 mm3 [95% confidence interval, 272.81-453.02] in the early group vs 161.14 mm3 [95% confidence interval, 124.31-197.97] in the late group, P < .001), and a lower complication rate related to exiting nerve root (16.0% in the early group vs 0% in the late group, P = .045).The learning curve of PETLD is not as difficult as that of other minimally invasive spine surgery technique. Although the overall outcomes were not different between the groups, the risks of incomplete decompression and exiting root injury-related complication were higher in the novice stage.

Learning curve of trans-sacral epiduroscopic laser decompression in herniated lumbar disc disease

BACKGROUND

Trans-sacral epiduroscopic laser decompression (SELD) using slender epiduroscope and a holmium YAG laser is one of the minimally invasive surgical options for lumbar disc herniation. However, the learning curve of SELD and the effect of surgical proficiency on clinical outcome have not yet been established. We investigated patients with lumbar disc herniation undergoing SELD to report the clinical outcome and learning curve.

METHODS

Retrospective analysis of clinical outcome and learning curve were performed at a single center from clinical data collected from November 2015 to November 2018. A total of 82 patients who underwent single-level SELD for lumbar disc herniation with a minimum follow-up of 6.0 months were enrolled. Based on the findings that the cut-off of familiarity was 20 cases according to the cumulative study of operation time, patients were allocated to two groups: early group (n = 20) and late group (n = 62). The surgical, clinical, and radiological outcomes were retrospectively evaluated between the two groups to analyze the learning curve of SELD.

RESULTS

According to linear and log regression analyses, the operation time was obtained by the formula: operation time = 58.825-(0.181 × [case number]) (p < 0.001). The mean operation time was significantly different between the two groups (mean 56.95 min; 95% confidence interval [CI], 49.12-64.78 in the early group versus mean 45.34 min; 95% CI, 42.45-48.22 in the late group; p = 0.008, non-parametric Mann-Whitney U test). Baseline characteristics, including demographic data, clinical factors, and findings of preoperative magnetic resonance imaging, did not differ between the two groups. Also, there was no significant difference in terms of surgical outcomes, including complication and failure rates, as well as clinical and radiological outcomes between the two groups.

CONCLUSION

The learning curve of SELD was not as steep as that of other minimally invasive spinal surgery techniques, and the experience of surgery was not an influencing factor for outcome variation.

Minimally invasive anterior cervical discectomy and fusion: a valid alternative to open techniques

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is a well-standardized treatment for cervical myelopathy/radiculopathy. The aim of this study is to assess the feasibility of minimally invasive ACDF.

METHOD

Retrospective review of six patients who underwent minimally invasive ACDF using microscope and tubular retractors. Clinical and radiological outcomes and surgical complications were reviewed.

CONCLUSION

Minimally invasive microscopic ACDF through tubular retractors is a feasible option and therefore an alternative to conventional open procedures. However, it does require advanced technical skills and good understanding of the MIS principles and limitations of the technique.

Evaluation of bony fusion after anterior cervical discectomy: a systematic literature review

PURPOSE

Anterior cervical discectomy and fusion (ACDF) has proven effective in treating radicular arm pain. Post-operatively, cervical spine stability is temporarily challenged, but data on bony fusion and speed of fusion are ambiguous; optimum evaluation method and criteria are debated.

AIM

To study bony fusion accomplishment and to obtain an overview of methods to evaluate fusion.

METHODS

A literature search was performed in PubMed and Embase. Included studies had to report original data concerning 1- or 2-level ACDF with intervertebral device or bone graft, where bony fusion was assessed using CT scans or X-rays.

RESULTS

A total of 146 articles comprising 10,208 patients were included. Bony fusion was generally defined as "the presence of trabecular bridging" and/or "the absence of motion". Fusion was accomplished in 90.1% of patients at the final follow-up. No gold standard for assessment could be derived from the results. Addition of plates and/or cages with screws resulted in slightly higher accomplishment of fusion, but differences were not clinically relevant. Eighteen studies correlated clinical outcome with bony fusion, and 3 found a significant correlation between accomplishment and better clinical outcome.

CONCLUSIONS

In approximately 90% of patients, bony fusion is accomplished one year after ACDF. As there is no generally accepted definition of bony fusion, different measuring techniques cannot be compared to a gold standard and it is impossible to determine the most accurate method. Variations in study design hamper conclusions on optimising the rate of bony fusion by choice of material and/or additives. Insufficient attention is paid to correlation between bony fusion and clinical outcome. These slides can be retrieved from electronic supplementary material.

Endoscopic Anatomy and Features of Anterior Cervical Foraminotomy by Destandau Technique

BACKGROUND:

Minimally invasive spine surgery limits surgical trauma and avoids traditional open surgery so in the majority of cases, recovery is much quicker and patients have less pain after surgery.

AIM:

The authors describe an endoscopic approach to anterior cervical foraminotomy (ACF) by Destandau’s method.

MATERIAL AND METHODS:

Anterior cervical foraminotomy by Destandau’s method is carried out under general anaesthesia. A 3 cm transverse skin incision is used just slightly past the anterior border of the sternocleidomastoid’s muscle laterally. After exposing and dissecting superficial cervical fascia, platysma muscle, and deep cervical fascia, Endospine material designed by Destandau will be inserted. As from this moment, the procedure will continue using endoscopy.

RESULTS:

the Endoscopic approach to anterior cervical foraminotomy by Destandau’s method offers a convenient access to the cervical foraminal stenosis with fewer complications and negligible morbidity and gives maximum exposure to discal space with the goal of minimising cutaneous incision.

CONCLUSION:

Contrary to the other minimally invasive approaches, the visual field in foraminotomy by Destandau technique is broad and depending on the workability of Endospine an adequate access to cervical disc is possible.

Complications associated with the initial learning curve of minimally invasive spine surgery: a systematic review

BACKGROUND

There is an inherently difficult learning curve associated with minimally invasive surgical (MIS) approaches to spinal decompression and fusion. The association between complication rate and the learning curve remains unclear.

QUESTIONS/PURPOSES

We performed a systematic review for articles that evaluated the learning curves of MIS procedures for the spine, defined as the change in frequency of complications and length of surgical time as case number increased, for five types of MIS for the spine.

METHODS

We conducted a systematic review in the PubMed database using the terms "minimally invasive spine surgery AND complications AND learning curve" followed by a manual citation review of included manuscripts. Clinical outcome and learning curve metrics were categorized for analysis by surgical procedure (MIS lumbar decompression procedures, MIS transforaminal lumbar interbody fusion, percutaneous pedicle screw insertion, laparoscopic anterior lumbar interbody fusion, and MIS cervical procedures). As the most consistent parameters used to evaluate the learning curve were procedure time and complication rate as a function of chronologic case number, our analysis focused on these. The search strategy identified 15 original studies that included 966 minimally invasive procedures. Learning curve parameters were correlated to chronologic procedure number in 14 of these studies.

RESULTS

The most common learning curve complication for decompressive procedures was durotomy. For fusion procedures, the most common complications were implant malposition, neural injury, and nonunion. The overall postoperative complication rate was 11% (109 of 966 cases). The learning curve was overcome for operative time and complications as a function of case numbers in 20 to 30 consecutive cases for most techniques discussed within this review.

CONCLUSIONS

The quantitative assessment of the procedural learning curve for MIS techniques for the spine remains challenging because the MIS techniques have different learning curves and because they have not been assessed in a consistent manner across studies. Complication rates may be underestimated by the studies we identified because surgeons tend to select patients carefully during the early learning curve period. The field of MIS would benefit from a standardization of study design and collected parameters in future learning curve investigations.

Cervical microendoscopic discectomy and fusion: does it affect the postoperative course and the complication rate? A blinded randomized controlled trial

STUDY DESIGN

A blinded randomized controlled trial.

OBJECTIVE

The purpose of this study was to evaluate the cervical microendoscopic discectomy and fusion.

SUMMARY OF BACKGROUND DATA

Minimally invasive treatment of spinal disorders allows surgeons to have direct access to the pathology with a reduced surgical morbidity, which is reflected over the improved postoperative course. Minimally invasive techniques for cervical discectomy including the posterior microendoscopic discectomy and the percutaneous endoscopic discectomy have a high success rate but are limited by the narrow range of indications. Lately, preliminary reports about cervical microendoscopic discectomy and fusion (CMEDF) showed high success rates without restrictions in the indications.

METHODS

Seventy consecutive patients were randomly assigned in 2 equal groups, the first operated by the "gold standard" anterior cervical discectomy and fusion and the second by CMEDF. Blinding included the patient-until dressing removal, the evaluating physician, and the radiologist throughout the entire study. The mean follow-up period was 28 months and outcome has been assessed using the Japanese Orthopaedic Association score, Odom criteria and the visual analogue scale. In addition, the operative time, complication rate, hospitalization, and the postoperative analgesic doses were recorded.

RESULTS

The functional outcome of the CMEDF at the final follow-up was 91% good to excellent. Results in the open group were very similar. Meanwhile, CMEDF demonstrated improved cosmesis, reduced laryngopharyngeal complication rate, postoperative analgesics, and hospital stay.

CONCLUSION

The results of the CMEDF are very promising. However, a much larger patient series from multicenter studies is still required for drawing up a final conclusion.

LEVEL OF EVIDENCE

1.

Ossification of the posterior longitudinal ligament: a review

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, the elderly, and Asian patients. There are many diseases associated with OPLL, such as diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, and other spondyloarthropathies. Several factors have been reported to be associated with OPLL formation and progression, including genetic, hormonal, environmental, and lifestyle factors. However, the pathogenesis of OPLL is still unclear. Most symptomatic patients with OPLL present with neurological deficits such as myelopathy, radiculopathy, and/or bowel and bladder symptoms. There are some reports of asymptomatic OPLL. Both static and dynamic factors are related to the development of myelopathy. Plain radiography, CT, and MR imaging are used to evaluate OPLL extension and the area of spinal cord compression. Management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be made case by case, depending on the patient's condition, level of pathology, type of OPLL, and the surgeon's experience. In this paper, the authors attempt to review the incidence, pathology, pathogenesis, natural history, clinical presentation, classification, radiological evaluation, and management of OPLL.

Sagittal segmental alignment as predictor of adjacent-level degeneration after a cloward procedure

BACKGROUND

The Cloward anterior interbody fusion is commonly performed for cervical disc herniation or spondylosis. In followup studies, various authors have noted clinically relevant adjacent-level degeneration. However, factors associated with adjacent-level degeneration are not well known.

QUESTIONS/PURPOSES

We asked whether the postoperative sagittal segmental alignment of the fused vertebrae could be used as a predictor of adjacent-level degeneration.

METHODS

We retrospectively studied 107 patients, aged 35 to 55 years, with one-level cervical disc disease between C4 and C7 operated on from 1985 to 1995 by discectomy and one-level anterior cervical fusion according to the Cloward procedure. In standard radiographs of the cervical spine in lateral view, the alignment of the involved intervertebral space (sagittal segmental alignment) and the sagittal alignment of the cervical spine were measured and the adjacent-level degeneration was assessed using the Kellgren and Lawrence criteria. The minimum followup was 10 years (mean, 16 years; range, 10-23 years).

RESULTS

Preoperatively, mean sagittal segmental alignment was 0.6°±2.0° and sagittal alignment of the cervical spine was 17.0°±4.9°. At last followup, the mean sagittal segmental alignment was 1.8°±4.1° and mean sagittal alignment of the cervical spine was 19.7°±6.6°. Adjacent-level degeneration was present in 60% of cases with postoperative sagittal segmental alignment of 0° or less and in 27% of cases with postoperative sagittal segmental alignment of more than 0°.

CONCLUSIONS

To prevent adjacent-level degeneration, we recommend proper lordotic sagittal segmental alignment when anterior interbody fusion of the cervical spine is indicated.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.