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

Sensitivity of Computed Tomography Compared With that of Magnetic Resonance Myelography in the Presurgical Diagnosis of Foraminal or Extraforaminal Entrapment at the Lumbosacral Junction

STUDY DESIGN

This is a retrospective analysis.

OBJECTIVE

To investigate and compare the sensitivities of computed tomography (CT) and magnetic resonance myelography (MRM) in the presurgical diagnosis of foraminal or extraforaminal entrapment of the L5 nerve.

SUMMARY OF BACKGROUND DATA

CT is more clinically available than MRM. Foraminal or extraforaminal entrapment at the lumbosacral junction may cause L5 radiculopathy but is difficult to diagnose. Asymmetric enlargement of the anterior primary division (APD) of the L5 nerve on preoperative CT and dorsal root ganglion (DRG) swelling and abnormal L5 nerve course on MRM coronal images have been examined in cases of foraminal or extraforaminal L5 nerve entrapment, but have not been compared directly.

MATERIALS AND METHODS

Ninety-five patients (mean age 63 y; 28-85 y) with L5 nerve entrapment at the lumbosacral junction who underwent preoperative CT and MRM, and microsurgical decompression by a single surgeon (K.-H.M.) from January 2010 to June 2014 were included. Symptomatic sites were diagnosed by confirming L5 nerve entrapment intraoperatively. Two spinal surgeons independently compared the bilateral APD diameters of the L5 nerve on CT and the L5 nerve courses and DRG swelling on MRM coronal images.

RESULTS

The interobserver agreement of asymmetric APD swelling on CT and abnormal nerve course and DRG swelling on MRM were excellent (κ=0.808, 0.811, and 0.849, respectively), and the sensitivities were 81%, 84%, and 82% on the right, and 86%, 92%, and 90% on the left sides, respectively. There was no statistically significant difference in the sensitivity between APD swelling on CT and an abnormal nerve course or DRG swelling on MRM on the right (P=1.000 and 0.789) and left (P=0.727 and 1.000) sides, respectively.

CONCLUSIONS

CT has comparable sensitivity to MRM for the presurgical diagnosis of L5 nerve entrapment at the lumbosacral junction.

LEVEL OF EVIDENCE

Level II.

Management of an unusual sciatica

PURPOSE

Extraforaminal entrapment of the L5 nerve root is uncommon, and its management can sometimes be very challenging.

METHODS

We present the case of a 57-year-old female, complaining of a sciatica in her left leg, for 3 years, with no response to any kind of conservative treatment. MRI and CT scan revealed the presence of a large L5S1 strictly lateral osteophyte compressing the left L5 root in its extraforaminal path.

RESULTS

The patient underwent a left anterior retroperitoneal approach with assistance from a vascular surgeon given the very close relation between the osteophyte and the left common iliac vein, lying just on top of it, osteophyte was removed in one piece with the use of an osteotome after retraction of the vessels. The patient progressively recovered from her left sciatic pain with a satisfactory clinical result at 1 year.

CONCLUSION

Literature is sparse on the treatment of extraforaminal entrapment of the L5 nerve root; the current case shows a successful treatment strategy with the use of an anterior approach for direct vision of the lesion and good control of the vessels.

Approach to the pediatric athlete with back pain: more than just the pars

Back pain in a pediatric patient can present a worrisome and challenging diagnostic dilemma for any physician. Although most back pain can be attributed to muscle strains and poor mechanics, it is necessary to appreciate the full differential of etiologies causing back pain in the pediatric population. The physician must recognize areas of mechanical weakness in the skeletally immature spine and the sport specific forces that can predispose a patient to injury. A comprehensive history involves determining the onset, chronicity, and location of the pain. A focused physical exam includes a neurological exam as well as provocative testing. The combination of a thorough history and focused physical exam should guide appropriate imaging. Radiographic tests are instrumental in narrowing the differential, making a diagnosis, and uncovering associated pathology. Treatment modalities such as activity modification, heat/cold compresses, and NSAIDs can provide pain relief and allow for effective physical therapy. In most cases nonoperative methods are successful in providing a safe and quick return to activities. Failure of conservative measures requires referral to an orthopedic surgeon, as surgical intervention may be warranted.

Extraforaminal compression of the L-5 nerve root at the lumbosacral junction: clinical analysis, decompression technique, and outcome

OBJECT

Extraforaminal compression of the L-5 nerve encompasses multiple pathological entities and may result from disc herniations as well as bony (osteophytes or sacral ala) or ligamentous (sacroiliac ligament and lumbosacral band) compression. Several other factors, such as disc space collapse or coronal wedging, can also contribute to narrowing of the extraforaminal space. The extraforaminal space at L5-S1 has unique anatomical features compared with the upper lumbar levels, which makes surgical access to this region difficult. Minimally invasive techniques offer easier access to the region. The purpose of this study was to analyze the contributing factors for extraforaminal compression of the L-5 nerve and assess clinical outcome following surgical decompression.

METHODS

Fifty-two consecutive patients who underwent a minimally invasive far-lateral approach for extraforaminal compression of the L-5 nerve were retrospectively analyzed for clinical data, outcomes, and imaging features (type of disc prolapse, coronal wedging, degree of disc and facet degeneration, facet tropism, foraminal stenosis, osteophytes, and adjacent-level disease). The authors describe the surgical technique used in this study.

RESULTS

The mean age of the patient sample was 57 years. Sixteen patients each had an extraforaminal ruptured disc or contained protrusion, and the remaining 20 patients had disc protrusions extending into the foraminal region or the lateral recess. Associated foraminal stenosis was found in 38.5%, and adjacent-level stenosis was noted in 22 cases (42.3%) and spondylolisthesis in 4 (7.7%). Osteophytes were noted in 18 cases. A coronal wedging angle ≥ 3° was found in 46.2%, and the laterality of wedging corresponded to the symptomatic side in 91% of cases. Fifteen patients (28.8%) complained of postoperative dysesthesias, which completely resolved in all cases within 6 months. The incidence of dysesthesias was more common in the ruptured disc group. There were no differences in clinical outcome among the different types of disc prolapses. The mean preoperative and postoperative visual analog scale scores were 7.6 and 3.6, respectively. The mean preoperative and postoperative Japanese Orthopaedic Association (JOA) scores were 6.4 and 13.8, respectively. The mean JOA recovery rate was 86.1%. According to the Macnab functional grading system, 96% of the patients had excellent or good grades at follow-up.

CONCLUSIONS

A minimally invasive far-lateral approach to L5-S1 requires a good understanding of the regional anatomy and can provide good to excellent clinical results in properly selected cases. This approach is effective in decompressing the far-lateral and foraminal zones. Adequate preoperative diagnosis and tailoring the surgical procedure to address the relevant compressive element in each case is essential to achieving good clinical results.

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.

L5 radiculopathy caused by L5 nerve root entrapment by an L5-S1 anterior osteophyte

Background

L5 radiculopathy is a common problem that has several causes. Entrapment of the L5 nerve root by anterior osteophytes at the L5-S1 junction is rarely reported. Posterior decompression of the L5 nerve root is commonly performed, but anterior decompression of the L5 nerve root is not a frequently performed procedure. The purpose of this case report is to describe an uncommon case of L5 radiculopathy caused by the entrapment of the L5 nerve root by an anterior osteophyte.

Methods

We report the case of a 79-year-old man with a right lower extremity L5 radiculopathy causing excruciating pain, worsening with transitioning between seated and standing positions. Radiologic evaluation showed a large osteophyte coming off of the right anterolateral border of L5-S1. The osteophyte was excised through a right-sided anterior retroperitoneal approach. An anterior interbody fusion was performed at L5-S1.

Results

Postoperatively, the patient's pain was completely resolved. Six months after surgery, he remained symptom free.

Conclusions

Osteophytes at the L5-S1 junction can entrap the L5 nerve root. If nonoperative treatment fails, the osteophyte can be excised and the nerve can be safely decompressed through an anterior retroperitoneal approach.