Elsevier

World Neurosurgery

Volume 148, April 2021, Pages e101-e114
World Neurosurgery

Original Article
Effect of Dorsal Root Ganglion Retraction in Endoscopic Lumbar Decompressive Surgery for Foraminal Pathology: A Retrospective Cohort Study of Interlaminar Contralateral Endoscopic Lumbar Foraminotomy and Discectomy versus Transforaminal Endoscopic Lumbar Foraminotomy and Discectomy

https://doi.org/10.1016/j.wneu.2020.12.176Get rights and content

Objective

Postoperative dysesthesia (POD) is a common complication in surgery involving foraminal diseases, including lumbar foraminal or extraforaminal herniated nucleus pulposus (HNP). Minimal dorsal root ganglion (DRG) retraction is key to preventing POD. We compared the clinical results, safety, and efficacy between the paraspinal transforaminal approach requiring DRG retraction and the interlaminar contralateral approach without DRG retraction for foraminal and extraforaminal diseases.

Methods

A retrospective cohort study was performed of 50 patients who underwent uniportal transforaminal endoscopic lumbar foraminotomy and discectomy (TELD) and 50 patients who underwent anuniportal interlaminar contralateral endoscopic lumbar foraminotomy and discectomy (ICELF) because of lumbar foraminal HNP. The operated levels, combined degenerative diseases, postoperative complications, and POD were analyzed. The visual analog scale (VAS) pain scores, modified Oswestry Disability Index, and MacNab criteria for evaluating pain disability and response were analyzed.

Results

In the ICELF group (total, n = 7, 14%), there were 5 (10%) and 2 (4%) patients with POD grade 1 and 2, respectively. In the TELD group (total, n = 13, 26%), there were 7 (14%), 5 (10%), and 1 (2%) patients with POD grade 1, 2, and 3, respectively. The overall occurrence rate of grade 2 and greater POD was higher in the TELD group (n = 6, 12%) than in the ICELF group (n = 2, 4%). In the ICELF group, 3 of 9 patients (33%) with combined canal structure deforming diseases had POD, of whom none had POD of grade 2 and greater. In the TELD group, 4 of 7 patients (57%) with combined canal structure deforming diseases had POD, of whom all had POD of grade 2 and greater. Two surgical groups showed favorable clinical outcomes with the visual analog scale, Oswestry Disability Index, and MacNab criteria.

Conclusions

Both TELD and ICELF were found to treat foraminal or extraforaminal HNP with good clinical outcomes. ICELF might have a lower POD rate in complicated cases such as adjacent segment disease, degenerative spondylolisthesis, and isthmic spondylolisthesis. This surgical procedure could be an alternative in complicated cases or in patients with an anatomically limited L5-S1 level. However, the procedure is technically challenging to perform.

Introduction

Foraminal diseases, including lumbar foraminal or extraforaminal herniated nucleus pulposus (HNP), are challenging clinical problems in microscopic spinal surgery. The development of endoscopic spinal surgery provides a good alternative to traditional open surgery and can enable the surgical treatment of foraminal diseases. However, endoscopic spinal surgery for foraminal and far lateral HNP has been classified as “severely difficult” in the difficulty grading/scoring system of percutaneous endoscopic lumbar discectomy by Kim et al.1 This situation is the result of the potential risk of severe dorsal root ganglion injury (DRG) and segmental arterial bleeding–induced massive hematoma during the operation. Postoperative dysesthesia (POD) caused by exiting DRG injury is a complication of transforaminal endoscopic lumbar foraminotomy and discectomy (TELD) and does not occur during microscopic discectomy for intracanalicular HNP.2 However, POD can negatively affect patients' daily lives, even if only temporarily, thus reducing the benefits of TELD as a minimally invasive procedure. Therefore, the prevention of POD is key to achieving a successful endoscopic surgical outcome.

Recently, Kim et al. reported 3 studies describing the interlaminar contralateral approach for resolving the contralateral lateral recess, foraminal, and extraforaminal lesions with technical developments. The first study3 was a case series of early outcomes with interlaminar contralateral lumbar lateral recess and foraminal decompression in patients with unilateral radiculopathy from unilateral foraminal stenosis. The clinical outcomes were favorable, and there was no definite postoperative instability during the follow-up period. The investigators reported that this technique was not possible for extraforaminal lesions. The second study4 was a case report with technical notes on interlaminar contralateral foraminotomy with full uniportal endoscopy to treat root-level double-crushed lesions. Kim et al. performed a foraminoplasty to reach the extraforaminal and far lateral lesions using the channel-in-channel technique, with full decompression from the lateral recess to the far lateral region. Kim et al. used an endoscope with a larger diameter for lateral recess decompression and sublaminar laminectomy and then changed to an endoscope with a smaller diameter to resolve the lesions from the foramen to the far lateral region. Third, more advanced techniques using a small-diameter uniportal endoscope were reported by Wu et al.5 Targeted contralateral foraminal, and extraforaminal stenosis were successfully decompressed with minimal ipsilateral unaffected side disruption.

In the present study, we performed 2 different endoscopic approach techniques for foraminal and extraforaminal HNP: the paraspinal transforaminal endoscopic approach, and interlaminar contralateral approach, as described earlier.5 We aimed to compare the clinical results, safety, and efficacy between the transforaminal approach requiring DRG retraction and interlaminar contralateral approach without DRG retraction for foraminal and extraforaminal diseases.

Section snippets

Study Patients

This article is a retrospective cohort study of 50 patients who underwent uniportal TELD and 50 patients who underwent uniportal interlaminar contralateral endoscopic lumbar foraminotomy and discectomy (ICELF) because of lumbar foraminal HNP with minimal lumbar foraminal stenosis from January 2018 to January 2020 at a single center (Gangnam Nanoori Hospital, Seoul, Korea). A single senior spine surgeon performed all procedures. The sample size was set as 50 patients in each surgical group

Results

A total of 50 and 50 patients who had undergone TELD and ICELF, respectively, were included. The mean age was 63.56 ± 9.58 years (range, 25–79 years) in the ICELF group and 60.38 ± 14.78 years (range, 23–80 years) in the TELD group (Table 1). The mean follow-up duration was 12.94 ± 3.93 months (range, 6–23 months) in the ICELF group and 12.86 ± 5.44 months (range, 7–22 months) in the TELD group (Table 1). The treated spinal levels were L2-L3 (n = 1, 2%), L3-L4 (n = 6, 12%), L4-L5 (n = 22, 44%),

TELD Development for Less POD Occurrence

TELD and decompression allow for the easy removal of migrated discs, foraminal to extraforaminal discs, and recurrent discs with advanced instruments such as an endoscopic drill, laser, and radiofrequency probe.7,10,11 Foraminal diseases, including lumbar foraminal or extraforaminal HNP, are challenging to resolve even in endoscopic spinal surgery. They have been classified as severely difficult grade because of approach-related complications.

With the transforaminal endoscopic approach, we have

Conclusions

Both TELD and ICELF effectively treat foraminal or extraforaminal HNP with good clinical outcomes. ICELF might have a lower POD rate in complicated cases such as those with ASD, DSPL, and ISPL. This surgical procedure could be a safe and efficacious alternative in complicated cases or at the anatomically limited L5-S1 level. However, the procedure is technically demanding to perform.

CRediT authorship contribution statement

Hyeun Sung Kim: Conceptualization, Methodology, Validation, Formal analysis, Writing - original draft. Ji Yeon Kim: Conceptualization, Methodology, Validation, Formal analysis, Data curation, Writing - review & editing. Pang Hung Wu: Visualization, Supervision, Writing - review & editing. Il-Tae Jang: Project administration, Visualization, Supervision.

Acknowledgments

We thank Keong Rae Kim, who contributed to the statistical analysis of the data, and Jae Eun Park for coordinating the scientific research. We would like to thank Editage (www.editage.co.kr) for English language editing.

References (16)

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Ji Yeon Kim and Hyeun Sung Kim contributed equally and are co-first authors.

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