We report 3 cases of conjoined nerve root anomalies identified during micro-endoscopic discectomy (MED). Between 2009 and 2010, 61 men and 20 women aged 18 to 84 (mean, 42) years underwent MED for symptomatic lumbar disc herniation of L3–4 (n=1), L4–5 (n=44), and L5–S1 (n=36). Magnetic resonance imaging (MRI), myelogram, and post-myelo computed tomography did not identify the anomalies. All 3 patients were male and had type 2A S1 conjoined nerve roots, with a herniated disc at L5-S1. None of them had any preoperative pseudolocalising neurological signs, but all demonstrated stiffer positive straight leg raise sign and deterioration of the Achilles tendon reflex. Postoperatively, all 3 patients achieved excellent clinical outcomes
CannonBWHunterSHPicazaJA. Nerve-root anomalies in lumbar-disc surgery. J Neurosurg1962;19:208–14.
2.
KikuchiSHasueMNishiyamaKItoT. Anatomic and clinical studies of radicular symptoms. Spine (Phila Pa 1976)1984;9:23–30.
3.
OkuwakiTKunogiJHasueM. Conjoined nerve roots associated with lumbosacral spine anomalies. A case report. Spine (Phila Pa 1976)1991;16:1347–9.
4.
ChotigavanichCSawangnatraS. Anomalies of the lumbosacral nerve roots. An anatomic investigation. Clin Orthop Relat Res1992;278:46–50.
5.
KadishLJSimmonsEH. Anomalies of the lumbosacral nerve roots. An anatomical investigation and myelographic study. J Bone Joint Surg Br1984;66:411–6.
6.
HaijiaoWKotiMSmithFWWardlawD. Diagnosis of lumbosacral nerve root anomalies by magnetic resonance imaging. J Spinal Disord2001;14:143–9.
7.
PamirMNOzekMMOzerAFKelesGEErzenC. Surgical considerations in patients with lumbar spinal root anomalies. Paraplegia1992;30:370–5.
8.
PeysterRGTeplickJGHaskinME. Computed tomography of lumbosacral conjoined nerve root anomalies. Potential cause of false-positive reading for herniated nucleus pulposus. Spine (Phila Pa 1976)1985;10:331–7.
9.
PostacchiniFUrsoSFerroL. Lumbosacral nerve-root anomalies. J Bone Joint Surg Am1982;64:721–9.
10.
NeidreAMacNabI. Anomalies of the lumbosacral nerve roots. Review of 16 cases and classification. Spine (Phila Pa 1976)1983;8:294–9.
11.
IzumidaSInoueS. Japanese Orthopedic Association Assessment of surgical treatment of low back pain [in Japanese]. J Jpn Orthop Assoc1986;60:391–4.
12.
HirabayashiKMiyakawaJSatomiKMaruyamaTWakanoK. Operative results and postoperative progression of ossification among patients with ossification of cervical posterior longitudinal ligament. Spine (Phila Pa 1976)1981;6:354–64.
