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Preoperative plain radiographs. Spina bifida occulta at the L5 neural arch was detected in the anteroposterior direction (white arrow), and slight disc space narrowing at the L4/5 and L5/S intervertebral disc levels was seen in the lateral direction (open arrows). a a-p view. b lateral view.
Source publication
Background
A nerve root anomaly, typified by a conjoined nerve root, is a rare finding. Conjoined nerve root anomalies are easily missed even in preoperative advanced imaging modalities, which can be potentially troublesome during and after surgery. In this report, we present a case of conjoined right L5–S1 nerve root in a patient with lumbar disc...
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Citations
... Nerve root anomalies are known differential diagnoses of herniated intervertebral discs [2]. In recent case reports, CNR was not diagnosed using preoperative imaging during the management of CNR accompanied by lumbar disc herniation [6,7]. Symptomatic undiagnosed CNR is a cause of failed back surgery because a simple discectomy without adequate decompression of the lateral recess and intervertebral foramen does not address the pathology [2,5]. ...
Background
In patients with conjoined nerve roots, hemilaminectomy with sufficient exposure of the intervertebral foramen or lateral recess is required to prevent destabilization and ensure correct mobility of the lumbosacral spine. To the best of our knowledge, no case reports have detailed the long-term course of conjoined nerve roots after surgery.
Case presentation
We report the case of a 51-year-old Japanese man with a conjoined nerve root. The main symptoms were acute low back pain, radiating pain, and right leg muscle weakness. Partial laminectomy was performed with adequate exposure to the conjoined nerve root. The symptoms completely resolved immediately after surgery. However, the same symptoms recurred 7 years postoperatively. The nerve root was compressed because of foraminal stenosis resulting from L5–S disc degeneration. L5–S transforaminal lumbar interbody fusion was performed on the contralateral side because of an immobile conjoined nerve root. At 44 months after the second surgery, the patient had no low back pain or radiating pain, and the muscle weakness in the right leg had improved.
Conclusions
This is the first report of the long-term course of conjoined nerve root after partial laminectomy. When foraminal stenosis occurs after partial laminectomy, transforaminal lumbar interbody fusion from the contralateral side may be required because of an immobile conjoined nerve root.
... A prevalence of 14-30% has been reported in cadaveric studies [7,9]. A classification of the different nerve root anomalies was made and adjusted over the years [8,10,11]. Nerve root anomalies are divided into conjoined (type 1), redundant (type 2), anastomotic (type 3), and confluent (type 4) nerve root anomalies [8]. ...
... In human patients, some authors believe that nerve root anomalies can cause signs of back pain or radicular pain, even in the absence of associated disc or bone pathology [7,8], but most authors only report clinical signs in patients where the malformed nerve roots were compressed or entrapped [10,16,[27][28][29]. Because the abnormal nerve roots are less mobile, they are more easily affected by minor compressions such as disc herniations or protrusions [27]. ...
Vertebral and spinal cord anomalies are well known in veterinary medicine. However, nerve root anomalies are seldomly reported. In human patients, nerve root anomalies can cause back pain and radicular pain. In human medicine, nerve root anomalies are more often found in cadaveric studies than in imaging studies, representing the lack of advanced imaging in the past and the unawareness about these pathologies. Additionally, nerve root anomalies can mimic other pathologies in imaging studies. It is important to know about the anatomy of the individual patient not only for correctly localizing the pathology but also for surgical planning and to prevent iatrogenic trauma to the patient. Conjoined nerve roots are a type of nerve root anomaly described in human medicine and are defined as two nerve roots that either share a common dural envelope at some point during their course from the dural sac or that have their origin very close together in the dural sac. In humans, lumbosacral nerve roots are most commonly conjoined, and signs of pain may be associated with this anomaly. We report the magnetic resonance imaging finding of right-sided conjoined L7 and S1 nerve roots in a dog that presented with lumbosacral hyperesthesia. We postulate that it is possible that the conjoined nerve roots played a role in the clinical signs of this dog. This is an anomaly that has not been reported before in veterinary medicine.
... Так, H. Kuroki та T. Nagai наводять випадок зрощення L5 і S1 корінців у пацієнтки зі spina bifida occulta. Аномалія встановлена інраопераційно під час видалення секвестрованої грижі диска L5-S1 [21]. Okuwaki T. et al. описали зрощення L5-S1 на тлі дефекту дуги L5 з явищами вираженої радикулопатії, але взагалі без пролабування структур міжхребцевого диска [22]. ...
... Системні дослідження й аналіз накопиченого матеріалу дали змогу виокремити дві основні клінічні ознаки, що дають змогу, хоч не підтвердити, але принаймні передбачити наяв-Клінічні випадки / Clinical сases ність аномалії. Це залучення двох суміжних дермотомів за наявності грижового випинання на одному рівні та негативний симптом Лассега в разі вираженої радикулопатії [21,31]. ...
... Найінформативніший метод діагностики АКПКО -МР-нейрографія [39,40]. Перспективність застосування цього методу діагностики показано в роботах A. Sharma et al., H. Kuroki et al. [21,30]. На жаль, у вітчизняній практиці цей метод діагностики не поширений. ...
Aim. The objective of this study is to analyze the clinical course of lumbosacral spinal nerve root anomalies / variants Type I according to the A. Neidre and I. MacNab’s classification, along with a retrospective MRI data analysis before surgery, focusing on the unique branching and topography of the spinal nerve roots. Additionally, we aim to address the relevance of correlating preoperative visualized features with the presence of anatomical anomalies attributed to these spinal nerve root variations, and their implications on the clinical presentation. Our study aims to compare our findings with the global diagnostic experience, classification, and specific aspects of performing discectomies based on individual anatomical characteristics of the lumbosacral region. Results. We present data from our own observation, when during surgery, a probable verification of a Type I lumbosacral spinal nerve root anomaly / variation according to the A. Neidre and I. MacNab’s classification was discovered in a patient. The anomaly appeared as a dense mass resembling a nerve root in the structural characteristics but with a significantly larger diameter. It emerged from the dural space at the level of the upper third of the L5 arch and then divided into two parts. A thinner bundle, comparable in diameter to a normal nerve root, exited through the L5-S1 intervertebral foramen, while a considerably thicker bundle followed a path parallel to the axis of the dural sac and exited through the S1-S2 intervertebral foramen. Comparison with global clinical observations revealed that despite the significant clinical and surgical implications, several aspects of this anomaly remain poorly studied and require further exploration and systematization. Conclusions. The lumbosacral nerve root anomalies (LSNRA) demonstrate a variety of structural variations and branching patterns, which are reflected in different classifications. Among the professional community, the classification of LSNRA, developed by A. Neidre and I. MacNab in 1983 and supplemented by S. M. Burke et al. in 2013, is recognized as the most relevant and frequently applied. While changes in vertebral bone structures can be easily diagnosed using modern imaging methods, preoperative diagnosis of LSNRA proves to be challenging, and the informativeness of standard MRI is limited, as confirmed by the clinical case presented. The dissonance between prominent neurological symptoms and relatively minor disc protrusion allows for the potential presence of a root variation/anomaly when planning the lumbar spine discectomy. The most informative diagnostic method for LSNRA is MR neurography. Among the radiological signs of Type I lumbоsacral nerve root anomalies, the following are considered valid: “corner sign”, “fat crescent sign”, and “parallel sign”. The verification of LSNRA is predominantly intraoperatively based on a series of characteristic topographicanatomical features, including atypical locations of the root’s origin from the dural sac, “unusual” nerve root exit angle, even up to a right angle, and technical challenges in root mobilization during routine lumbar discectomy procedures.
We present three cases of L5-S1 disc herniation accompanied by the conjoined nerve root (CNR) anomaly that affects the S1 nerve root. All patients in these cases are female and they experienced radiating pain within the L5 and S1 dermatomes. Detailed MRI scans confirmed the presence of lumbar disc herniation (LDH) specifically at the L5-S1 level. The surgical approach undertaken included a partial hemilaminectomy and facetectomy at the L5-S1 level. While two of the cases exclusively underwent decompression procedures, the third case involved not only decompression but also the extraction of the herniated disc material. Although two patients found complete relief from their pain, one patient continued to experience pain even after the surgical intervention. Subsequently, the latter patient underwent an additional procedure involving spinal cord stimulation (SCS), resulting in remarkable improvement in their symptoms. These three cases serve to underscore the significance of considering the presence of CNR, particularly in situations where even minor instances of LDH result in severe symptoms affecting the lower extremities. In addition, this consideration is important when symptoms cannot be directly attributed to a single nerve root. It is worth noting that surgical decompression alone may not always be sufficient for pain relief in patients having CNR. This case highlights the potential of SCS as an effective solution for patients with CNR suffering from LDH. Hence, the incorporation of SCS should be contemplated as an adjunct treatment for CNR, especially when standard decompression procedures fall short of providing the desired relief. This study effectively demonstrates strategic approaches to address CNR-associated symptoms evident in cases of L5-S1 disc herniation. In addition, it emphasizes the necessity of tailoring treatment strategies to suit individual patients, thereby optimizing the potential outcomes.
