Ligaments of the lumbosacral spine and their role in possible extraforaminal spinal nerve entrapment and tethering

A comparative study of the anatomy and MRI images of the lumbar foraminal ligaments at the L1-L5 levels

PURPOSE

The purpose of this study was to evaluate the ability of MRI images to reveal foraminal ligaments at levels L1-L5 by comparing the results with those of anatomical studies.

METHODS

Eighty lumbar foramina were studied. First, the best MRI scanning parameters were selected, and the transverse and sagittal axes of each lumbar foramina were scanned to identify and record the ligament-like structures in each lumbar foramen. Then, the cadaveric specimens were anatomically studied, and all ligament structures in the lumbar foramina were retained. The number, morphology and distribution of ligaments under anatomical and MRI scanning were observed. Histological staining of the dissected ligament structures was performed to confirm that they were ligamentous tissues. Finally, the accuracy of ligament recognition in MRI images was statistically analyzed.

RESULTS

A total of 233 foraminal ligaments were identified in 80 lumbar intervertebral foramina through cadaveric anatomy. The radiating ligaments (176, 75.5%) were found to be attached from the nerve root to the surrounding osseous structures, while the transforaminal ligaments (57, 24.5%) traversed the intervertebral foramina without any connection to the nerve roots. A total of 42 transforaminal ligament signals and 100 radiating ligament signals were detected in the MRI images of the 80 intervertebral foramina.

CONCLUSION

The MRI can identify the lumbar foraminal ligament, and the recognition rate of the transforaminal ligament is higher than that of the radiating ligament. This study provides a new method for the clinical diagnosis of the relationship between the lumbar foraminal ligament and radicular pain.

Foraminal Ligaments Tether Upper Cervical Nerve Roots: A Potential Cause of Postoperative C5 Palsy

Background  Nerve root tethering upon dorsal spinal cord (SC) migration has been proposed as a potential mechanism for postoperative C5 palsy (C5P). To our knowledge, this is the first study to investigate this relationship by anatomically comparing C5–C6 nerve root translation before and after root untethering by cutting the cervical foraminal ligaments (FL).

Objective  The aim of this study is to determine if C5 root untethering through FL cutting results in increased root translation.

Methods  Six cadaveric dissections were performed. Nerve roots were exposed via C4–C6 corpectomies and supraclavicular brachial plexus exposure. Pins were inserted into the C5–C6 roots and adjacent foraminal tubercle. Translation was measured as the distance between pins after the SC was dorsally displaced 5 mm before and after FL cutting. Clinical feasibility of FL release was examined by comparing root translation between standard and extended (complete foraminal decompression) foraminotomies. Translation of root levels before and after FL cutting was compared by two-way repeated measures analysis of variance. Statistical significance was set at 0.05.

Results  Significantly more nerve root translation was observed if the FL was cut versus not-cut, p  = 0.001; no difference was seen between levels, p  = 0.33. Performing an extended cervical foraminotomy was technically feasible allowing complete FL release and root untethering, whereas a standard foraminotomy did not.

Conclusion  FL tether upper cervical nerve roots in their foramina; cutting these ligaments untethers the root and increases translation suggesting they could be harmful in the context of C5P. Further investigation is required examining the value of root untethering in the context of C5P.

Lumbar foraminal neuropathy: an update on non-surgical management

Lumbar foraminal pathology causing entrapment of neurovascular contents and radicular symptoms are commonly associated with foraminal stenosis. Foraminal neuropathy can also be derived from inflammation of the neighboring lateral recess or extraforaminal spaces. Conservative and interventional therapies have been used for the treatment of foraminal inflammation, fibrotic adhesion, and pain. This update reviews the anatomy, pathophysiology, clinical presentation, diagnosis, and current treatment options of foraminal neuropathy.

Extraforaminal L5 Nerve Root Compression Caused by Intervertebral Osteophyte Accompanied by Lumbosacral Transitional Vertebra: A Case Treated by Anterior Approach

BACKGROUND

Several authors have reported the occurrence of extraforaminal L5 nerve root compression between lumbosacral transitional vertebrae (LSTV) and sacral ala, but reports on a lesion caused by an intervertebral osteophyte on the ventral and contralateral side of a unilateral abnormality by LSTV are hardly available.

CASE DESCRIPTION

A 67-year-old woman presented with pain along the distribution of the L5 nerve root; straight leg raise test, femoral nerve stretch test, and Kemp test were positive on the left. Following plain radiographs, computerized tomography, magnetic resonance imaging, and selective nerve root block, an osteophyte bridging the L5 and S1 vertebral bodies in the ventral side was identified compressing the L5 nerve root. On account of resistance to conservative therapy and the delicate position of the lesion, surgical treatment was performed by an anterior decompression. Subsequently, the patient attained adequate relief from pain and could walk normally.

CONCLUSION

We herein present a very rare case of extraforaminal L5 nerve root compression caused by an intervertebral osteophyte on the ventral and contralateral side of a unilateral abnormality by LSTV, which was managed by anterior decompression.

Effectiveness of Percutaneous Lumbar Extraforaminotomy in Patients with Lumbar Foraminal Spinal Stenosis: A Prospective, Single-Armed, Observational Pilot Study

Objective

In lumbar foraminal spinal stenosis (LFSS), numerous ligaments may play an important role in causing radiculopathy by narrowing the exit of the nerve root. In order to achieve effective decompression of lumbar foraminal ligaments, a specially designed instrument for percutaneous lumbar extraforaminotomy (PLEF) was invented. The purpose of this study was to evaluate the effectiveness of PLEF in patients with intractable radiculopathy from LFSS.

Design

A prospective, single-armed, observational pilot study.

Setting

A pain center in a tertiary university-based hospital.

Methods

The PLEF was performed in patients who suffered from radiculopathy with concordant imaging evidence of a mild to severe degree of LFSS. For each patient, an 11-point numerical rating scale (NRS) pain score, the Oswestry Disability Index (ODI), the Roland Morris Disability Questionnaire (RMDQ) score, and any adverse events were evaluated at three-month follow-ups. Successful responder percentage defined as 40% or greater reduction from baseline NRS score with no increase in ODI, and the RMDQ score was assessed at three months.

Results

Among 26 patients who underwent PLEF, 20 patients completed the study protocol. PLEF was successful in 12 patients (60%). The overall mean pain reduction at three months was 36.3%. Patients who responded well also showed improvement in the ODI (-20%) and RMDQ score (-8.4) at their three-month follow-up. No serious complications were reported in the study.

Conclusions

The PLEF can be an effective and safe treatment option, as well as a minimally invasive procedure, for the management of patients suffering from refractory radiculopathy caused by LFSS.

Extraforaminal compression of the L5 nerve: An anatomical study with application to failed posterior decompressive procedures

This anatomical study was performed to elucidate the pertinent foraminal and lateral L5 nerve anatomy to enhance our understanding of possible neurologic causes of failed decompression surgery. Persistent extraforaminal L5 nerve compression is a possible cause of persistent symptoms following lumbosacral surgery. The amount of extraforaminal space for the L5 ventral ramus was examined in fifty adult human skeletons (100 sides). Based on morphology, the specimens were then categorized (types I-IV) on the basis of the bony space available for the nerve at this location. Next, 25 embalmed adult cadavers (50 sides) underwent bilateral dissection of the lower lateral lumbar region. The type of bony extraforaminal outlet was documented for each cadaver on the basis of our skeletal analysis. Lastly, segments (intra- and extra-foraminal) of the L5 ventral ramus were excised and examined histologically. Types I-IV outlets were found in 43, 31, 20 and 6 skeletal sides, respectively. For cadavers, 22,15, 10 and 3 sides were found to have types I-IV bony outlets, respectively. In cadavers, all type IV outlets and 70% of the type III bony configurations adjacent to the L5 ventral ramus had signs of neural irritation/injury including vascular hyalinization and increased fibrosis distal to the intervertebral foramen. No distal segments of type I and type II outlets showed histological signs of neural compromise. Patients with symptoms referable to L5 nerve compression for whom no proximal pathology is identified could warrant investigation of the more distal extraforaminal segment of this nerve.

A controlled study on the anatomy of cervical extraforaminal ligaments and three-dimensional fast-imaging employing a steady-state acquisition sequence

PURPOSE

To evaluate the utility of magnetic resonance three-dimensional fast-imaging employing a steady-state acquisition (MR 3D-FIESTA) sequence to study cervical EFLs using the anatomical results of cadavers as the gold standard.

METHODS

Part I: The cervical regions of five embalmed adult cadavers were scanned using the MR 3D-FIESTA sequence. Ligamentous structures in the intervertebral foramina (IVFs) between C4 and T1 in the MRI scans were identified by a radiologist. Part II: After the specimens were scanned, gross and microscopic anatomical studies were conducted on the IVFs between C4 and T1 in the specimens by an anatomist. Part III: Using the anatomical results of the cadavers as the gold standard, the utility of the MR 3D-FIESTA sequence for imaging cervical EFLs was evaluated. Specificity, sensitivity, positive and negative predictive values (PPV and NPV, respectively) and accuracy were calculated.

RESULTS

The occurrence rate of transforaminal ligaments (TFLs) in the IVFs between C4 and T1 was 42.5%. The results obtained by the radiologist using the MR 3D-FIESTA sequence to identify TFLs are as follows: specificity 96.2%, sensitivity 76.5%, PPV 92.9%, NPV 86.2%, and accuracy 88.4%.

CONCLUSION

MR 3D-FIESTA sequences clearly showed cervical EFLs. In the 3D-FIESTA sequence scans that the radiologist believed to indicate the presence of a cervical TFL, the probability that the TFL existed was approximately 93%. When the radiologist believed that no TFL was present in the 3D-FIESTA sequence scan, the probability that a TFL existed was 14%.

The Surgical Anatomy of the Lumbosacroiliac Triangle: A Cadaveric Study

OBJECTIVE

The anatomic area delineated medially by the lateral part of the L4-L5 vertebral bodies, distally by the anterior-superior surface of the sacral wing, and laterally by an imaginary line joining the base of the L4 transverse process to the proximal part of the sacroiliac joint, is of particular interest to spine surgeons. We are referring to this area as the lumbo-sacro-iliac triangle (LSIT). Knowledge of LSIT anatomy is necessary during approaches for L5 vertebral and sacral fractures, sacral and iliac tumors, and extraforaminal decompression of the L5 nerve roots.

METHODS

We performed an anatomic dissection of the LSIT in 3 embalmed cadavers (6 triangles), using an anterior and posterior approach.

RESULTS

We identified 3 key tissue planes: the neurological plexus plane, constituted by L4 and L5 nerve roots; an intermediate level constituted by the ileosacral tunnel; and posteriorly, by the lumbosacral ligament, and the posterior muscular plane.

CONCLUSIONS

Improving anatomic knowledge of the LSIT may help surgeons decrease the risk of possible complications. When LSIT pathology is present, a lateral approach corresponding to the tip of the L4 transverse process, medially, is suggested to decrease the risk of vessel and nerve root damage.

Lumbar extraforaminal entrapment: performance characteristics of detecting the foraminal spinal angle using oblique coronal MRI. A multicenter study

BACKGROUND CONTEXT

Previous conventional magnetic resonance imaging reports on extraforaminal entrapment (e-FE) on L5-S1 have been problematic because of their complexity or lack of sensitivity and specificity. In this study, we propose a simple diagnostic method for e-FE.

PURPOSE

The purpose of this study was to determine the sensitivity and specificity of using the difference in the foraminal spinal nerve (FSN) angle of the L5 nerve, as determined by oblique coronal T2-weighted imaging (OC-T2WI), for diagnosing L5-S1 unilateral e-FE.

STUDY DESIGN

The study design involves diagnostic accuracy with retrospective case-control study.

PATIENT SAMPLE

Seventy consecutive patients with unilateral L5 radiculopathy who underwent unilateral L5-S1 extraspinal canal decompression for e-FE or 4/5 intraspinal canal decompression for lumbar spinal canal stenosis between 2009 and 2013 were included.

OUTCOME MEASURES

The Japanese Orthopedic Association score, Visual Analog Scale score for leg pain, and OC-T2WI for the FSN angle of the L5 nerve were examined.

METHODS

The 70 patients were divided into two groups: Group A (n=21) with unilateral L5-S1 e-FE and Group B (n=49) with intraspinal canal L4-L5. Group C (n=44) comprised the control group, which included only patients with back pain without leg radiculopathy. All patients underwent OC-T2WI, and the differences in the FSN angle of the fifth lumbar spinal nerve between the symptomatic and asymptomatic sides (ΔFSN angle) were examined and compared among the groups.

RESULTS

There were no significant differences in the patient characteristics among the three groups. The ΔFSN angle was 17° in Group A, 4.8° in Group B, and 6.4° in Group C, and the laterality was significantly larger in Group A than in the other two groups. A receiver-operating characteristic curve showed areas under the curve between groups A and B and between groups A and C of 0.93 and 0.97, respectively. In addition, the cutoff value of the ΔFSN angle (10°) indicated diagnostic accuracies of 94% and 91% (sensitivity and specificity) and of 93% and 95%, respectively.

CONCLUSIONS

Determining differences in the FSN angle between the symptomatic and asymptomatic sides of greater than 10° via OC-T2WI represented a simple, readily available, and complementary diagnostic method for lumbar e-FE.

Improved accuracy of diagnosis of lumbar intra and/or extra-foraminal stenosis by use of three-dimensional MR imaging: comparison with conventional MR imaging

BACKGROUND

The purposes of this study were to assess the reliability of 3-dimensional magnetic resonance (MR) imaging (3D MRI) and conventional MRI (CMRI) for detection of lumbar intra and/or extra-foraminal stenosis (LIEFS) and to compare the diagnostic accuracy of the 2 imaging modalities.

METHODS

A total of 60 sets of 3D MR and CMR images from 20 healthy volunteers and 40 LIEFS patients were qualitatively rated according to defined criteria by 3 independent, blinded readers. Kappa statistics were used to characterize intra and inter-reader reliability for qualitative rating of data. Multireader, multicase analysis was used to compare lumbar foraminal stenosis detection between the 2 modalities.

RESULTS

Intra-reader agreement for 3D MRI was excellent, with kappa = 0.90; that for CMRI was good, with kappa = 0.78. Average inter-reader agreement for 3D MRI was good, with kappa = 0.79, whereas that for CMRI was moderate, with kappa = 0.41. Average area under the ROC curve values (1st reading/2nd reading) for detection of lumbar foraminal stenosis using 3D MRI and CMRI were 0.99/0.99 and 0.94/0.92, respectively. Detection of LIEFS with 3D MRI was significantly better than with CMRI (P = 0.0408/0.0294).

CONCLUSIONS

These results suggest that CMRI was of limited use for detection of the presence of LIEFS. Isolated imaging with CMRI may risk overlooking the presence of LIEFS. In contrast, reliability of 3D MRI for detection of LIEFS was good. Furthermore, readers' performance in the diagnosis of LIEFS can be improved by use of 3D MRI. Therefore, 3D MRI is recommended when using imaging for diagnosis of LIEFS.

A new electrophysiological method for the diagnosis of extraforaminal stenosis at L5-s1

Study Design

A retrospective study.

Purpose

To examine the effectiveness of using an electrodiagnostic technique as a new approach in the clinical diagnosis of extraforaminal stenosis at L5-S1.

Overview of Literature

We introduced a new effective approach to the diagnosis of extraforaminal stenosis at the lumbosacral junction using the existing electrophysiological evaluation technique.

Methods

A consecutive series of 124 patients with fifth lumbar radiculopathy were enrolled, comprising a group of 74 patients with spinal canal stenosis and a second group of 50 patients with extraforaminal stenosis at L5-S1. The technique involved inserting a pair of needle electrodes into the foraminal exit zone of the fifth lumbar spinal nerves, which were used to provide electrical stimulation. The compound muscle action potentials from each of the tibialis anterior muscles were recorded.

Results

The distal motor latency (DML) of the potentials ranged from 11.2 to 24.6 milliseconds in patients with extraforaminal stenosis. In contrast, the DML in patients with spinal canal stenosis ranged from 10.0 to 17.2 milliseconds. After comparing the DML of each of the 2 groups and at the same time comparing the differences in DML between the affected and unaffected side of each patient, we concluded there were statistically significant differences (p<0.01) between the 2 groups. Using receiver operating characteristic curve analysis, the cutoff values were calculated to be 15.2 milliseconds and 1.1 milliseconds, respectively.

Conclusions

This approach using a means of DML measurement enables us to identify and localize lesions, which offers an advantage in diagnosing extraforaminal stenosis at L5-S1.

Anterior decompression for far-out syndrome below a transitional vertebra: a report of two cases

BACKGROUND CONTEXT

Impingement of the L5 nerve between the transverse process of L5 and the ala of sacrum has been described as the far-out syndrome. Posterior decompression is often performed for this pathology.

PURPOSE

To describe rare cases of far-out syndrome below a transitional vertebra who underwent anterior decompression.

STUDY DESIGN/SETTING

A case report and a review of the literature.

METHODS

Review of the hospital medical record, history, physical examination, and imaging studies.

RESULTS

A 70-year-old woman and a 53-year-old man presented with prolonged and progressive leg pain and/or low back pain. Both of the patients showed muscle weakness and sensory disturbance at L5 level and lumbosacral transitional vertebra on the plain radiography. Magnetic resonance imaging showed huge osteophytes, and there was severe impingement of the L5 nerve at the anterior exit zone of the foramen. Anterior decompression was performed for both cases using a Fraser incision and resulted in successful resolution of the symptom and neurological status.

CONCLUSION

In the extraforaminal stenosis of the L5 nerve with far-out syndrome below the transitional vertebra, entrapment occurs more anterior of exit zone of the L5 nerve foramen than in the other pathologies; anterior decompression brings in more complete decompression.

Electrophysiological diagnosis using sensory nerve action potential for the intraforaminal and extraforaminal L5 nerve root entrapment

BACKGROUND

The diagnosis of lumbar intraforaminal and extraforaminal stenosis (lumbar foraminal stenosis) is sometimes difficult. However, sensory nerve action potential (SNAP) decreases in amplitude when the lesion is at or distal to the dorsal root ganglion. Therefore, the amplitude of SNAP with lumbar foraminal stenosis should be decreased. In this cohort study, the usefulness of SNAP for the preoperative diagnosis of L5/S foraminal stenosis was assessed.

METHODS

In 63 patients undergoing unilateral L5 radiculopathy, bilateral SNAPs were recorded for the superficial peroneal nerve (L5 origin). The patients were divided into two groups according to the results of imaging examinations. Group A (37 patients) included patients whose lesion was located only at the intraspinal canal. In group B (26 patients), the lesion was located only at the intra- or extraforaminal area. All patients received surgery and the symptoms were diminished. The ratios of the amplitudes of SNAPs on the affected side to that on the unaffected side were compared between groups A and B.

RESULTS

SNAPs could not be elicited bilaterally in four patients. The amplitude ratio for group B (median 0.42, max 1.17, min 0) was significantly lower than that in group A (median 0.85, max 1.43, min 0) (p < 0.001 by Mann-Whitney U test). Using a cut-off value of 0.5 for the amplitude ratio, the sensitivity for the diagnosis of lumbar foraminal stenosis was 91.3 % with a specificity of 85.7 %.

CONCLUSIONS

Measurement of SNAP could be useful to diagnose a unilateral L5/S foraminal stenosis.

Differentiation between symptomatic and asymptomatic extraforaminal stenosis in lumbosacral transitional vertebra: role of three-dimensional magnetic resonance lumbosacral radiculography

OBJECTIVE

To investigate the role of lumbosacral radiculography using 3-dimentional (3D) magnetic resonance (MR) rendering for diagnostic information of symptomatic extraforaminal stenosis in lumbosacral transitional vertebra.

MATERIALS AND METHODS

The study population consisted of 18 patients with symptomatic (n = 10) and asymptomatic extraforaminal stenosis (n = 8) in lumbosacral transitional vertebra. Each patient underwent 3D coronal fast-field echo sequences with selective water excitation using the principles of the selective excitation technique (Proset imaging). Morphologic changes of the L5 nerve roots at the symptomatic and asymptomatic extraforaminal stenosis were evaluated on 3D MR rendered images of the lumbosacral spine.

RESULTS

Ten cases with symptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. On 3D MR lumbosacral radiculography, indentation of the L5 nerve roots was found in two cases, while swelling of the nerve roots was seen in eight cases at the exiting nerve root. Eight cases with asymptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. Based on 3D MR lumbosacral radiculography, indentation or swelling of the L5 nerve roots was not found in any cases with asymptomatic extraforaminal stenosis.

CONCLUSION

Results from 3D MR lumbosacral radiculography Indicate the indentation or swelling of the L5 nerve root in symptomatic extraforaminal stenosis. Based on these findings, 3D MR radiculography may be helpful in the diagnosis of the symptomatic extraforaminal stenosis with lumbosacral transitional vertebra.

Unsuspected reason for sciatica in Bertolotti's syndrome

Patients with Bertolotti's syndrome have characteristic lumbosacral anomalies and often have severe sciatica. We describe a patient with this syndrome in whom standard decompression of the affected nerve root failed, but endoscopic lumbosacral extraforaminal decompression relieved the symptoms. We suggest that the intractable sciatica in this syndrome could arise from impingement of the nerve root extraforaminally by compression caused by the enlarged transverse process.

Transitional lumbosacral segment with unilateral transverse process anomaly (Castellvi type 2A) resulting in extraforaminal impingement of the spinal nerve: a pathoanatomical study of four specimens and report of two clinical cases

The spinal nerve can be pinched between the transverse process of the fifth lumbar vertebra and the sacral ala. The patients are divided into two types: elderly persons with degenerative scoliosis and somewhat younger adults with isthmic spondylolisthesis. For the first time, we describe extraforaminal impingement of the spinal nerve in transitional lumbosacral segment with unilateral transverse process anomaly. Selective nerve root blocks were performed in two clinical cases. One patient underwent nerve root decompression via a posterior approach. One year after operation, this patient reported no radicular or lumbar pain. The pathoanatomical study demonstrated pseudoarthrosis between the transverse process and the ala of the sacrum and showed dysplastic facet joints at the level below the transitional vertebra in all specimens. Furthermore, we present the oldest illustration of this pathological condition, published in a book by Carl Wenzel in 1824. Extraforaminal entrapment of the spinal nerve in transitional lumbosacral segment with unilateral transverse process anomaly can cause radiculopathy, and osteophytes are the cause of the entrapment. Dysplastic facet joints on the level below the transitional vertebra could be one reason for "micromotion" resulting in pseudoarthrosis with osteophytes. Sciatica relief was obtained by means of selective nerve root blocks or posterior decompression via a dorsomedial approach.

The role of computed tomography in the presurgical diagnosis of foraminal entrapment of lumbosacral junction

OBJECTIVE

On the basis of preoperative computed tomography (CT) scans, we studied the change of the size of anterior primary division (APD) of the L5 spinal root in the presence of foraminal/extraforaminal entrapment of the L5 spinal root.

METHODS

Two independent radiologists retrospectively reviewed the preoperative CT scans of 27 patients treated surgically and compared the sizes of the APDs on bilateral L5 spinal roots. If one side APD size was larger than the other side APD size, it was described as left or right "dominancy" and regarded this as "consensus (C)" in case that there was a consensus between the larger APD and the location of sciatica, and regarded as "non-consensus (NC)" in case that there was not a consensus. Oswestry Disability Index (ODI) scores were used for preoperative and postoperative evaluation.

RESULTS

On CT scans, twenty-one (77%) of 27 patients were the consensus group (APD swelling) and 6 (22%) were a non-consensus group (APD no swelling). In 9 patients with acute foraminal disc herniations, asymmetric enlargement of the APD on L5 spinal root was detected in all cases (100%) and detected in 11 (64%) of 17 patients with stenosis. Preoperative ODI score was 75-93 (mean 83) and postoperative ODI scores were improved to 13-36 (mean 21). The mean follow-up period was 6 months (range, 3-11 months).

CONCLUSION

An asymmetric enlargement of the APD on L5 spinal root on CT scans is meaningfully associated with a foraminal or extraforaminal entrapment of the L5 spinal root on the lumbosacral junction.

Posterior decompression surgery for extraforaminal entrapment of the fifth lumbar spinal nerve at the lumbosacral junction

Object

In this paper, the authors' goal was to elucidate the clinical features and results of decompression surgery for extraforaminal stenosis at the lumbosacral junction.

Methods

Twenty-eight patients with severe leg pain caused by extraforaminal stenosis at the lumbosacral junction (18 men and 10 women; mean age 68.2 ± 8.9 years) were treated by posterior decompression without fusion using a microendoscope in 19 patients and a surgical microscope or loupe in 9 patients. The decompression procedures consisted of partial resection of the sacral ala, the L-5 transverse process, and the L5–S1 facet joint along the L-5 spinal nerve. The following items were investigated: 1) preoperative neurological findings; 2) preoperative radiological findings, including plain radiographs, CT scans, selective radiculography of L-5; 3) surgical outcome as evaluated using the Japanese Orthopaedic Association scale for low-back pain (JOA score); and 4) need for revision surgery.

Results

All patients presented with neurological deficits compatible with a diagnosis of L-5 radiculopathy such as weakness of the extensor hallucis longus muscle and sensory disturbance in the L-5 area together with neurogenic claudication. On plain radiographs, 21 patients (75%) and 17 patients (60.7%) exhibited lumbar scoliosis (≥ 5°) and wedging of the L5–S1 intervertebral space (≥ 3°), respectively. The CT scans demonstrated marked osteophyte formation at the posterolateral margin of the L5–S1 vertebral bodies, and a selective L-5 nerve root block was effective in all patients. All patients reported pain relief immediately after surgery. The mean JOA scores were 11.3 ± 3.8 before surgery and 24.3 ± 3.4 at the time of the final follow-up examination; the recovery rate was 68.6 ± 16.5%. The mean estimated blood loss was 66.6 ± 98.6 ml, and the mean surgical time was 135.3 ± 46.5 minutes. No significant difference in the recovery rate of the JOA scores or in the surgical time and blood loss was observed between the 2 surgical approaches. Four patients underwent revision posterior interbody fusion for the recurrence of radicular pain as a result of intraforaminal stenosis in 3 patients and insufficient decompression of the extraforaminal area in the remaining patient at an average of 19.5 months after surgery.

Conclusions

Extraforaminal stenosis at the lumbosacral junction is a rare but distinct pathological condition causing L-5 radiculopathy. Decompression surgery without fusion using a microendoscope or a surgical microscope/ loupe is a feasible and less invasive surgical option for elderly patients with extraforaminal stenosis at the lumbosacral junction.

PATHOANATOMIC BASIS FOR STRETCH-INDUCED LUMBAR NERVE ROOT INJURY WITH A REVIEW OF THE LITERATURE

OBJECTIVE

Persistent pain originating from a dysfunctional lumbar motion segment poses significant challenges in the clinical arena. Although the predominance of the existing spine literature has addressed nerve root compression as the principal cause of pain, it is equally likely that a stretch mechanism may be responsible for all or part of the pathology.

METHODS

The literature supporting the role of stretch damage as a primary cause of nerve root injury and pain was systematically reviewed. Pathoanatomic considerations between nerve roots and juxtaposed environment are described and correlated with the available literature. Potential anatomic relationships that may lead to stretch-induced injury are delineated.

RESULTS

A dynamic lumbar functional spinal unit that encloses a tethered nerve root can create significant stretch and/or compression. This phenomenon may be present in a variety of pathological conditions. These include anterior, posterior, and rotatory olisthesis as well as degenerative conditions such as the loss of disc interspace height and frank multisegment spinal deformity. Although numerous studies have demonstrated that stretch can result in nerve damage, the pathophysiology that may associate nerve stretch with chronic pain has yet to be determined.

CONCLUSION

The current literature concerning stretch-related injury to nerve roots is reviewed, and a conceptual framework for its diagnosis and treatment is proposed and graphically illustrated using cadaveric specimens. The dynamic biomechanical and functional interrelationships between neural structures and adjacent connective tissue elements are particularly important in the face of spinal deformity.

The clinical features of, and microendoscopic decompression for, extraforaminal entrapment of the L5 spinal nerve

OBJECTIVE

To evaluate the clinical results of, and surgical techniques for, microendoscopic (METRx) decompression of extraforaminal entrapment of the L5 spinal nerve at the lumbosacral tunnel.

METHODS

Five patients with extraforaminal entrapment of the L5 spinal nerve in the lumbosacral tunnel were treated in our department, including three men and two women. The average age was 65.6 years. All patients suffered severe leg pain and neurological deficits compatible with L5 radiculopathy. Minimally invasive decompression of the L5 spinal nerve was performed under METRx intertransverse decompression.

RESULTS

With an average follow-up of 17.8 months, clinical results were assessed based on Nakai criteria and Visual Analogue scale (VAS). All patients experienced immediate pain relief postoperatively. Clinical outcomes were excellent in three patients and good in two. The average intraoperative blood loss was 59 ml, with an average operative time of 103 min. Average post-operative stay in bed was 7 days, and average cost was $1860.

CONCLUSION

Extraforaminal entrapment of the L5 spinal nerve in the lumbosacral tunnel can cause L5 radiculopathy. METRx partial resection of the L5 transverse processes, sacral ala and osteophytes of L5-S1 vertebral bodies to relieve extraforaminal entrapment of the L5 spinal nerve is a very effective and minimally invasive surgical option.

Basic Science Research Related to Chiropractic Spinal Adjusting: The State of the Art and Recommendations Revisited

OBJECTIVE

The objectives of this white paper are to review and summarize the basic science literature relevant to spinal fixation (subluxation) and spinal adjusting procedures and to make specific recommendations for future research.

METHODS

PubMed, CINAHL, ICL, OSTMED, and MANTIS databases were searched by a multidisciplinary team for reports of basic science research (since 1995) related to spinal fixation (subluxation) and spinal adjusting (spinal manipulation). In addition, hand searches of the reference sections of studies judged to be important by the authors were also obtained. Each author used key words they determined to be most important to their field in designing their individual search strategy. Both animal and human studies were included in the literature searches, summaries, and recommendations for future research produced in this project.

DISCUSSION

The following topic areas were identified: anatomy, biomechanics, somatic nervous system, animal models, immune system, and human studies related to the autonomic nervous system. A relevant summary of each topic area and specific recommendations for future research in each area were the primary objectives of this project.

CONCLUSIONS

The summaries of the literature for the 6 topic sections (anatomy, biomechanics, somatic nervous system, animal models, immune system, and human studies related to the autonomic nervous system) indicated that a significant body of basic science research evaluating chiropractic spinal adjusting has been completed and published since the 1997 basic science white paper. Much more basic science research in these fields needs to be accomplished, and the recommendations at the end of each topic section should help researchers, funding agencies, and other decision makers develop specific research priorities.

Microendoscopic partial resection of the sacral ala to relieve extraforaminal entrapment of the L-5 spinal nerve at the lumbosacral tunnel

✓ The authors report the cases of three patients with L-5 radiculopathy caused by extraforaminal entrapment of the L-5 spinal nerve at the lumbosacral tunnel; this structure comprises the lumbosacral ligament, the sacral ala, and the L-5 and S-1 vertebral bodies. All three patients suffered severe leg pain and neurological deficits compatible with L-5 radiculopathy. Decompressive surgery involved the microendoscopic partial resection of the sacral ala along the L-5 spinal nerve. All patients experienced immediate pain relief postoperatively. Microendoscopic partial resection of the sacral ala is an effective and minimally invasive surgical option for patients with extraforaminal entrapment of the L-5 spinal nerve.

Anatomic Analysis of the Transforaminal Ligament in the Lumbar Intervertebral Foramen

OBJECTIVE:

The objective of this study was to evaluate the clinical significance of the transforaminal ligaments (TFLs) in relation to the area of the lumbar intervertebral foramen (IVF) by analyzing cadaveric spines.

METHODS:

One hundred ninety-eight cadaveric lumbar IVFs were studied, and the existence and type of TFLs were identified. All IVFs were photographed, and the images were saved. The areas of the IVFs and TFLs were measured with the Scion Image for Windows image analysis program.

RESULTS:

TFLs were found in 82.8% of the IVFs. The oblique inferior transforaminal ligament was the most common. The mean area of the IVFs was 155.8 ± 51.1 mm2, and the mean area occupied by the TFLs was 46.3 ± 37.6 mm2. The mean percentage of the IVF area occupied by the TFLs was 28.5 ± 18.8%.

CONCLUSION:

TFLs are common structures in the IVF and may reduce the space available for the spinal nerve root within the IVF. In this circumstance, any compromise of the IVF may impinge on the nerve root.

Lumbar spine region pathology and hamstring and calf injuries in athletes: is there a connection?

This paper discusses the theory that subtle lumbosacral canal impingement of the L5 nerve root may be a relatively common occurrence in older footballers and may in fact be a common underlying basis for the age related predisposition towards hamstring and calf strains.

Evaluation of transforaminal ligaments by magnetic resonance imaging

OBJECTIVES

Three-part study to (1) identify and describe transforaminal ligaments (TFLs), (2) determine the best low-field-strength magnetic resonance imaging (MRI) technique for TFLs, and (3) determine the ability of low-field-strength MRI to obtain images of TFLs.

DESIGN

Part I-descriptive anatomic study; part II-descriptive MRI study; part III-blinded comparison of diagnostic test against gold standard (MRI vs anatomic dissection).

SETTING

Chiropractic college gross anatomy laboratory and MRI facilities.

SPECIMENS

Three anatomic specimens of male cadavers age 60 to 85 years; a fourth specimen was used for training radiologists in part III.

MAIN OUTCOME MEASURES

Part I-number and size of TFLs; part II-subjective grading of highest quality MRI images; part III-specificity, sensitivity, positive predictive value, negative predictive value, percent agreement, and accuracy of identifying TFLs from MRI scans.

MAIN RESULTS

Part I-19 TFLs identified in 30 intervertebral foramina (IVFs) (60% of IVFs had TFLs), thick = 4 (21%), medium thickness = 12 (63.2%), thin = 3 (15.8%); part II-TFLs demonstrated to best advantage with pure sagittal plane, T(1)-weighted MRI; part III-average: specificity = 88.9%, sensitivity = 45.6%, positive predictive value = 86.7%, negative predictive value = 50.8%, percent agreement = 78%, and accuracy = 62.4%.

CONCLUSIONS

The number of TFLs was in general agreement with previous research. Images of TFLs can be successfully imaged with low-field-strength MRI. If a trained radiologist identifies a TFL, there is an 87% chance that one is present, and if a trained radiologist does not identify a TFL in an intervertebral foramen, there remains a 51% chance that one is present.

Extraforaminal entrapment of the fifth lumbar spinal nerve by osteophytes of the lumbosacral spine: anatomic study and a report of four cases

STUDY DESIGN

An anatomic study of the associations between the fifth lumbar spinal nerve (L5 spinal nerve) and a lumbosacral tunnel, consisting of the fifth lumbar vertebral body (L5 vertebral body), the lumbosacral ligament, and sacral ala, and clinical case reports of four patients with lumbar radiculopathy secondary to entrapment of the L5 spinal nerve in the lumbosacral tunnel.

OBJECTIVES

To delineate the anatomic, clinical, and radiologic features and surgical outcome of patients with entrapment of the L5 spinal nerve in the lumbosacral tunnel.

SUMMARY OF BACKGROUND DATA

Although several cadaveric studies on a lumbosacral tunnel as a possible cause of L5 radiculopathy have been reported, few studies had focused on osteophytes of the L5-S1 vertebral bodies as the major component of this compressive lesion, and clinical reports on patients with this disease have been rare.

METHODS

Lumbosacral spines from 29 geriatric cadavers were examined with special attention to the associations between osteophytes of the L5-S1 vertebral bodies and the L5 spinal nerve. Four patients with a diagnosis of the entrapment of the L5 spinal nerve by osteophytes at the lumbosacral tunnel were treated surgically, and their clinical manifestations and surgical results were reviewed retrospectively.

RESULTS

The anatomic study demonstrated osteophytes of the L5-S1 vertebral bodies in seven of the 29 cadavers. Entrapment of the L5 spinal nerve in the lumbosacral tunnel was observed in six of the seven cadavers with L5-S1 osteophytes but in only one of the 22 cadavers without such osteophytes (P < 0.05, chi2 test). All four patients had neurologic deficits in the L5 nerve root distribution. MRI and myelography showed no abnormal findings in the spinal canal, but CAT scans demonstrated prominent osteophytes on the lateral margins of L5-S1 vertebral bodies in all four. Selective L5 nerve block completely relieved all patients of pain but only temporarily. Three patients were treated via a posterior approach by resecting the sacral ala along the L5 spinal nerve, and the other patient was treated by laparoscopic anterior resection of the osteophytes. Pain relief was obtained in the four patients immediately after surgery, but one patient experienced recurrence of pain 1 year after the first surgery and was successfully treated by additional posterior decompression and fusion.

CONCLUSIONS

Extraforaminal entrapment of L5 spinal nerve in the lumbosacral tunnel can cause L5 radiculopathy, and osteophytes of L5-S1 vertebral bodies are a major cause of the entrapment.

Lumbar intrathecal ligaments

A meticulous examination was performed on 56 vertebral columns from cadavers between 64 and 89 years of age. Identification of all contents within the dural sac was completed; however, the main focus was the cauda equina and lumbar region. In addition to scope dissection, radiographs and histological preparations were used to identify structures, tissue types, and any possible pathology. Discrete intrathecal ligamentous bands were observed in all cadavers examined. They were found randomly binding the dorsal nerve roots of the cauda equina to the dura. Occasional binding of the ventral nerve roots to the dorsal roots was observed. Histological examination demonstrated a dense collagen ligament varying between 0.13 and 0.35 microm in thickness and from 3 mm to 3.5 cm in length. The average number of ligaments found per cadaver was 18. These ligaments displayed a broad base attachment to the nerve root or dura of approximately 3 mm. Looping of the nerve roots associated with these ligaments was seen in one cadaver with a burst fracture. Electron microscopic studies of these ligaments demonstrated similarities to denticulate ligaments. It is suggested that the intrathecal ligaments represent remnants from fetal development of the denticulate ligaments.