Conjoint nerve root (CNR) is an embryological nerve root anomaly that mainly involves the lumbosacral region. The presence of CNR during tubular discectomy raises the chances of failure in spinal surgery and the risk of neural injuries. Tubular discectomy can be challenging in the presence of CNR owing to limited visualization. Here, we present a technical note on two cases of L5–S1 disc prolapse in the presence of conjoint S1 nerve root that was operated via a minimally invasive tubular approach. Any intraoperative suspicion of CNR while using the tubular approach should prompt the surgeon to perform a thorough tubular decompression prior to nerve root retraction. In patients with a large disc, disc should be approached via the axilla because the axillary area between the dura and the medial boarder of the root is very easy to approach in the presence of CNR. Safe performance of tubular discectomy is possible even in the presence of CNR in the lumbar spine.
Conjoint nerve root (CNR) is embryological nerve root anomaly that is most commonly observed in the lumbosacral region. The incidence of CNR varies from 2% to 17.3% [
A 64-year-old man presented with left-sided lumbar radiculopathy that had persisted for 3 months; the severity of his symptoms had increased in the previous 20 days. His clinical examination revealed sensory deficit in left S1 dermatome. Magnetic resonance imaging (MRI) confirmed broad left paracentral disc prolapse at L5–S1 compressing the left S1 nerve root and the left-sided thecal sac (
After using a routine tubular approach, the surgeon observed that the dura and the S1 nerve root were unusually tense and difficult to retract safely for performing discectomy. The MRI had shown a moderate paracentral disc prolapse; therefore, this was an unusual finding considering the level L5–S1. This prompted to undercutting of the facets using a high-speed burr to create more space for retraction. Undercutting of the facets revealed the presence of CNR (
The patient has consented to the submission of the case report for submission to the journal.
A 40-year-old woman presented with left-sided radiculopathy and neurological claudication for 3 months. The patient had a VAS of 9 and an ODI of 34 with claudication distance of 50 m. MRI showed left paracentral herniation at L5–S1 that compressed the left S1 root and left-sided thecal sac. After failed conservative treatment, the patient was scheduled for surgery with a left-sided tubular approach.
Similar to that in the previous case, intraoperative undercutting of the left facet joints revealed the presence of conjoint roots (
The patient has consented to the submission of the case report for submission to the journal.
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 [
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.
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Magnetic resonance imaging showing broad left paracentral disc at L5–S1 compressing left S1 nerve root and left sided thecal sac.
Intraoperative image showing conjoint nerve root after undercutting ipsilateral left facet. Conjoint roots are marked as 1 & 2, and dura is marked as 3.
Intraoperative image showing successful over the top decompression of contralateral side. Dura is marked as 3, and contralateral left S1 root is marked as 4.
Postoperative magnetic resonance neurography confirming type 1a nerve root sleeve of the left S1 and S2 roots.
Intraoperative image showing conjoint nerve root after undercutting ipsilateral left facet. Conjoint roots are marked as 1 & 2, and dura is marked as 3.
Intraoperative image showing disc being approached through the axilla between the conjoint roots and dura. Conjoint roots are marked as 1 & 2, and dura is marked as 3.
Intraoperative image showing disc being approached through the shoulder after retracting the conjoint roots medially. Conjoint roots are marked as 1 & 2, and dura is marked as 3.