Preoperative identification of CNR is based on a high degree of suspicion. The presence of neurological claudication with radiculopathy in a setting of a relatively small disc compression should raise the suspicion of CNR [4]. With advances in diagnostic modalities, there are increasing reports of CNR. MRI-based diagnosis of CNR is based on indirect imaging signs, such as asymmetry of dura (corner sign), atypical extradural fat (fat crescent sign), or angulation of existing nerve root (parallel sign) [6]. These indirect signs are not very specific and can be mimicked by disc herniation or extradural lesions. Newer diagnostic tools, such as MR neurography, can directly demonstrate CNRs [7]. MR neurography allows direct and more accurate diagnosis of neural variations and CNRs. With advances in MIS surgery, the tubular approach is rapidly becoming a popular method for discectomy. The MIS approach for spine surgeries uses a small surgical incision and less extensive muscle dissection, causing less postoperative pain, earlier discharge, and more rapid return to normal activities [8–10]. Tubular discectomy offers certain advantages; however, it has certain drawbacks, such as limited tubular visualization. Attempting a tubular discectomy in presence of CNR can be challenging because it raises the risk of neural injuries [11]. In the setting of disc prolapse with CNR, the presence of an additional nerve root further compromises an already compromised dural space. The tethering effect of CNRs and large cross-sectional area of abnormal nerve root make these surgeries more challenging with the additional risk of iatrogenic injury [12]. The key to successful surgery here is adequate removal of the prolapsed disc fragment and wise decompression of neural elements. These principles of surgery should be applied while attempting to use the tubular approach in CNR patients. After using a routine tubular approach, it is advised to burr or undercut the ipsilateral facet joint for complete visualization of the lateral most edge of the nerve roots. If root retraction is still difficult, the surgeon can attempt an over-the-top decompression of the dura. Once the dura is adequately mobile, the CNR could be retracted to the contralateral side along with the dura to safely remove the disc fragments. In cases with a large disc, the recommendation is to approach the disc through the axilla because the axillary area between the dura and the medial border of the root is easy to approach in the presence of CNR. Once the axillary disc is removed, the CNR can be mobilized medially to approach the disc through the shoulder area. Adequate decompression is crucial for the achievement of good surgical outcome in cases of tubular discectomy in the presence of CNR.

In conclusion, the presence of CNR during tubular discectomy can be challenging owing to limited visualization in the MIS approach. Any intraoperative suspicion should prompt the surgeon to perform thorough decompression before attempting nerve root retraction in patients with CNR. In patients with a large disc, the recommendation is to approach the disc through the axilla because the axillary area between the dura and medial boarder of the root is easier to approach in the presence of CNR.