Far-lateral Lumbar Disc Herniation Research Articles

A Retrospective Study of Far Lateral Midline Microlumbar Discectomy in 20 Patients at a Single Center in Turkey.

BACKGROUND Microdiscectomy is a minimally-invasive surgical technique for treating far lateral lumbar disc herniation (FLLDH). This retrospective study from a single center in Turkey aimed to evaluate midlinelumbar discectomy in 20 patients with far lateral lumbar disc herniation. MATERIAL AND METHODS We collected clinical data of 20 patients (11 men, 9 women) operated for FLDDH between January 2006 and January 2022. Patients' age, sex, surgical level, examination findings, motor deficit, duration of operation, complications during the operation and preoperative/postoperative 6 month visual analogue Scala (VAS), preoperative/postoperative 6th month Oswestry Disability Index (ODI) scores were evaluated. RESULTS The patients were 11 men (55%) and 9 women (45%), with a mean age of 52.08±11.21 years. The mean duration of symptoms before the operation was 3.4 weeks. Laseque sign positivity was found in 86.4% of the patients. Motor deficit was present in 30% of the patients. After 6-month follow-up, preoperative VAS value decreased from 9.35±0.75 to 0.84±0.75. Preoperative and postoperative VAS score averages were significantly different (P=0.0001). Operation ODI values were 73.63±3.76 before and after surgery, and decreased to 14.81±3.63 at 6 months. CONCLUSIONS The term distal lateral disc herniation was first defined in the literature in 1974 when the disc was seen in a different location than the normal location compared to the facet. Far lateral disc herniation can be operated on successfully with midline skin incision.

Efficacy of Epidural Steroid Injections and Evaluation of Surgical and Anesthetic Approaches in Far-Lateral Disc Herniations

Aim: To observe the long-term effect of epidural steroid injections (ESI) and describe surgical outcomes in patients with far-lateral lumbar disc herniations. Materials & methods: The medical records of 30 patients who underwent surgery for far-lateral lumbar disc herniations were reviewed. Results: ESI outcomes: pain scores decreased significantly after ESI (p=0.004). The surgery was delayed for 13.78±8.59 months in patients who received ESI. Surgical outcomes: the improvement in the leg pain was considerably more significant than the back pain (p<0.001). While motor deficit improved substantially (p<0.001), there was persistent sensory dysesthesia. Conclusion: ESI does not preventbut may delay the surgery up to 28 months. Although postoperative pain scores were significantly decreased, there was persistent back pain and sensory paresthesia.

Comparable effectiveness of transforaminal endoscopic spine system technique combined with selective nerve root block between far lateral lumbar disc herniation and central or paracentral herniation.

This study aims to compare the clinical effectiveness of transforaminal endoscopic spine system (TESSYS) technique combined with selective nerve root block (SNRB) in treating patients with far lateral lumbar disc herniation (FLDH) and patients with central or paracentral herniation (C/PDH). Between June 2015 and June 2019, a total of 204 patients (80 males, 124 females; mean age: 62.3±5.4 years; range, 51 to 66 years) with a herniated disc were included. Of these, 22 consecutive adult patients with FLDH formed the FLDH group, while 182 patients with C/PDH formed the C/PDH group. Considering that FLDH was a rare type of LDH and occurred outside the spinal canal, the patients with LDH in the spinal canal (C/PDH) were selected as the controls in our study. All cases received ultrasound-guided SNRB to identify the diseased disc and treated by the TESSYS technique. Data including demographics, duration of operation, duration of hospital stay, surgical cost, complications, Visual Analog Scale (VAS) scores for the back and leg, and Oswestry Disability Index (ODI) scores and the modified MacNab criteria were analyzed. The FLDH group presented the similar clinical outcomes and costs with the C/PDH group. No significant differences in the VAS score, ODI score, and Macnab score were observed between the groups (p>0.05 for all). Both groups showed the significantly improved postoperative VAS scores on Day 3, at 1, 3, 6, and 12 months compared to baseline. The postoperative ODI scores at 6 and 12 months were also significantly improved (p<0.05). At the final follow-up at 12 months, the FLDH group showed the MacNab criteria rating excellent and good of 81.8% and C/PDH group showed 84.62%. The FLDH patients presented the comparable clinical effectiveness with C/PDH patients. Based on these findings, the TESSYS technique combined with ultrasound-guided SNRB for FLDH is safe and feasible with caution, although the risk of nerve root injury may be worried.

Percutaneous Endoscopic Discectomy Via a Transforaminal Approach for L5/S1 Far-Lateral Disc Herniation Assisted by Intraoperative Computed Tomography

To examine the clinical outcomes of a percutaneous lumbar transforaminal endoscopic discectomy (PTED) with intraoperative computed tomography (iCT) navigation for the treatment of L5-S1 far-lateral lumbar disc herniation (LDH). A total of 30 patients with L5-S1 far-lateral LDH who underwent PTED with iCT navigation from September 2016 to October 2020 were enrolled in this study. Outcomes were assessed using the visual analog scale pain score, the Oswestry Disability Index, the Japanese Orthopedic Association score, the EQ-5D-5L and the modified Macnab criteria. Preoperative and postoperative complications were recorded. The mean visual analog scale score for leg pain improved from 8.1 at baseline to 2.3, 0.9, 0.7 and 0.9 at 1day, 1week, 6months, and 12months postoperatively, respectively (P < 0.01). The mean Oswestry Disability Index improved from 78.1% at baseline to 45.5%, 21.9%, 12.6%, and 11.7% at 1week, 1month, 6months, and 12months postoperatively, respectively (P < 0.01); and the mean Japanese Orthopedic Association score improved from 8.6 at baseline to 14.2, 20.2, 24.4, and 25.6 at 1day, 1week, 6months, and 12months postoperatively, respectively (P < 0.01). At 12months postoperatively, the EQ-5D-5L value significantly increased, from-0.061±0.138 to 0.903±0.064. The rate of a good or excellent modified Macnab result was 93% (26/28) at 12months postoperatively. In the present study, combined L5-S1 foraminal stenosis tended to lead poor outcomes, which required more postsurgical treatments. With iCT navigation, PTED is a feasible and effective minimally invasive surgery for L5-S1 far-lateral LDH.

Far lateral lumbar disc herniation part 1: Imaging, neurophysiology and clinical features.

Far lateral lumbar disc herniations (FLLDH) represent a separate category of disc pathology which includes both intraforaminal and extraforaminal lumbar disc herniations, that are characterized by a peculiar clinical presentation, diagnostic and treatment modalities as compared to the more frequent median and paramedian disc hernias. Surgical treatment often represents the only effective weapon for the cure of this disease and over the years different approaches have been developed that can reach the region of the foramen or external to it, with different degrees of invasiveness. The diagnosis is more demanding and still underestimated as it requires a more detailed knowledge in the spine anatomy and dedicated radiological studies. Computerized tomography and in particular magnetic resonance imaging are the appropriate tools for the diagnosis of FLLDH. Despite the widespread use of these diagnostic tests, many cases of FLLDH are overlooked due to insufficiently detailed radiological examinations or due to the execution of exams not focused to the foraminal or the extraforaminal region. Neurophysiological studies represent a valid aid in the diagnostic classification of this pathology and in some cases they can facilitate the differential diagnosis with other types of radiculopathies. In the present study, a comprehensive review of the clinical presentation, epidemiology, radiological study and the neurophysiological aspects is presented.

Full-endoscopic decompression for fifth lumbar radiculopathy due to a fragility sacral fracture associated with far-lateral L5/S1 disc herniation: A technical note

The prevalence of fragility sacral fractures has been increasing with the rise in the number of osteoporotic patients and the development of diagnostic imaging. Sacral fracture can cause injury to the fifth lumbar (L5) nerve, although the incidence is low. The therapeutic strategy for sacral fracture with neurological injury has not yet been established, and the surgical strategy for fragility sacral fracture is more controversial. We describe a new therapeutic method using endoscopic surgery for L5 nerve root involvement caused by far-lateral lumbar disc herniation triggered by a fragility sacral fracture. A 55-year-old woman presented with right buttock and right lower limb pain without signs of trauma. Neurological examination revealed paresis of the right lower limb and hypoesthesia in the region innervated by the right L5 nerve root. Neuroimaging demonstrated a U-shaped sacral fracture, including the sacral ala, and right L5 extra-foraminal stenosis. The L5 nerve root was located near the vertical fracture, and compressed by far-lateral L5/S1 disc herniation. Full-endoscopic spine surgery (FESS) was performed to partially remove the right S1 superior articular process and to resect the degenerated disc material. L5 radiculopathy improved partially after the surgery. We suggest that FESS is an effective and safe therapeutic method for fragility sacral fractures associated with far-lateral lumbar disc herniation.

Evaluation of the effectiveness of transforaminal epidural steroid injection in far lateral lumbar disc herniations.

Far lateral lumbar disc herniations (FLDH) consist approximately 0.7-12% of all lumbar disc herniations. Compared to the more common central and paramedian lumbar disc herniations, they cause more severe and persistent radicular pain due to direct compression of the nerve root and dorsal root ganglion. In patients who do not respond to conservative treatments such as medical treatment and physical therapy, and have not developed neurological deficits, it is difficult to decide on surgical treatment because of the nerve root damage and spinal instability risk due to disruption of facet joint integrity. In this study, we aimed to evaluate the effect of transforaminal epidural steroid injection (TFESI) on the improvement of both pain control and functional capacity in patients with FLDH. A total of 37 patients who had radicular pain caused by far lateral disc herniation which is visible in their lumbar magnetic resonance imaging (MRI) scan, had no neurological deficit and did not respond to conservative treatment, were included the study. TFESI was applied to patients by preganglionic approach. Pre-treatment Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores of the patients were compared with the 3rd week, 3rd month and 6th month scores after the procedure. The mean initial VAS score was 8.63 ± 0.55, while it was 3.84 ± 1.66, 5.09 ± 0.85, 4.56 ± 1.66 at the 3rd week, 3rd month and 6th month controls, respectively. This decrease in the VAS score was found statistically significant (p = 0.001). ODI score with baseline mean value of 52.38 ± 6.84 was found to be 18.56 ± 4.95 at the 3rd week, 37.41 ± 14.1 at the 3rd month and 34.88 ± 14.33 at the 6th month. This downtrend of pa-tient's ODI scores was found statistically significant (p = 0.001). This study has demonstrated that TFESI is an effective method for gaining increased functional capacity and pain control in the treatment of patients who are not suitable for surgical treatment with radicular complaints due to far lateral lumbar disc hernia.

Retrospective Analysis of Paraspinal Muscle-Splitting Microscopic-Assisted Discectomy Versus Percutaneous Endoscopic Lumbar Discectomy for the Treatment of Far-Lateral Lumbar Disc Herniation.

To compare percutaneous endoscopic lumbar discectomy (PELD) and the microscopic tubular technique, and to evaluate the outcomes of surgery. We collected information through retrospective analysis of patients with far-lateral lumbar disc herniation (FLLDH) from June 2015 to October 2018. Twenty-six patients underwent paraspinal muscle-splitting microscopicassisted discectomy (MD) and thirty patients underwent PELD surgery by the same surgical team. Data included the duration of the operation, duration of intraoperative radiation exposure, and average duration of hospitalization. Pre- and postoperative pain scores and neurological functions were recorded using the visual analog scale (VAS) score and Oswestry disability index (ODI). Fifty-six patients remained in the study over the 12-24 months period. The mean operating time was 65.83 ± 16.64 min in the PELD group, mean duration of radiation exposure was 154.98 ± 64.26 mGy, and average of hospitalization was 3.43 days. The mean operating time was 44.96 ± 16.87 min in the MD group, duration of radiation exposure was 42.12 ± 17.28 mGy, and duration of hospitalization was 4.12 days. There were two patients with postoperative transient dysesthesia and one underwent reoperation seven months after surgery in the PELD group. One patient had postoperative transient dysesthesia in the MD group. Except low back pain at three months (p > 0.05), all patients in both groups showed significant improvement in VAS and ODI scores compared with pre-operation and until final follow-up (p < 0.05). Both techniques are minimally invasive, effective, and safe for treating FLLDH in selected patients. Compared with the PELD technique, the MD procedure offers a wider field of vision during operation, shorter operation time, fewer postoperative complications, and shorter learning curve.

The interlaminar contralateral approach to far-lateral lumbar disc herniations: a single-center comparison with traditional techniques.

The interlaminar contralateral approach (ICA) is a promising surgical alternative for the treatment of far-lateral lumbar disc herniations (FLLDH). To date no study has compared ICA and FLLDH conventional surgical treatments, namely the intertransverse, the transmuscular and the intermuscular approaches, in terms of safety and outcome. Patients who underwent FLLDH surgery at our Institution between January 2015 and September 2018 were reviewed. ICA complications and clinical outcomes were compared with those of conventional approaches at 1-month postoperatively and at the last follow-up available. Improvement was defined as reduction of at least two point in the Visual Analogue Scale (VAS) or increase of at least 1 point in the Medical Research Council (MRC) scale of muscle strength. Patient-reported outcome was assessed with the Oswestry Disability Index (ODI). Among 38 patients, 18 underwent ICA and 20 a conventional approach (intertransverse in 16, transmuscular in two, intermuscular in two). Median follow-up was 21 months (range, 2-47). At 1 month, no differences between the two groups were noticed in terms of clinical outcome and symptoms relief (P> 0.05). The median postoperative ODI score was significantly lower in the Conventional approach group at 1 month (P<0.05), but this difference was no longer significant at the last follow-up evaluation (P>0.05). No differences were found between the two groups in surgical complication and recurrence rates. Our data suggest that the ICA is a safe and effective alternative to conventional approaches in FLLDH surgery. Larger prospective studies are needed to confirm our results.

L5-S1 FAR LATERAL DİSK HERNİASYONLU HASTALAR İÇİN İNTERTRANSVERS FASYA AÇILMADAN MEDİAN İNSİZYON İLE GERÇEKLEŞTİRİLEN LATERAL MİKROŞİRÜRJİKAL YAKLAŞIM: 12 HASTANIN RETROSPEKTİF DEĞERLENDİRİLMESİ

<div><!--block-->Objective: HL5-S1 far lateral lumbar disc herniations (FLLDH) are extremely rare disc pathologies and herniated disc is located on the lateral side of the pedicle. The aim of this study is to evaluate 12 patients suffering from L5-S1 FLLDH who were operated on using/via the lateral interpedicular microsurgical approach and to discuss in the context of the current literature.&nbsp;<br><br>Material and Method: 12 patients (5 male and 7 females) with L5-S1 FLLDH partcicpated/participated in this study. All patients were operated on between the year 2015 and 2017 at the same medical center using the lateral interpedicular microsurgical approach. After the midline skin incision, thoracolumbar fascia was opened at the side of the herniation, a subperiosteal dissection of paravertebral muscles was carried out and Taylor retractors were placed. Subsequently, minimal amounts of bone were removed from the fascet joints and pars interarticularis, the exiting nerve root was explored at the lateral of the pars interarticularis and a microsurgical removal of herniation was performed.&nbsp;<br><br>Results: The mean visual analog scores (VAS) decreased from 9.25±0.75 to 0.76±0.75 postoperatively and the difference between the preoperative and postoperative VAS scores was statistically significant (p=0.0001). 6 months after surgery 5 patients were graded as excellent (41.7%), 6 patients were good (50%) and 1 patient was fair (8.3%) according to the MacNab classification.&nbsp;<br><br>Conclusion: The lateral interpedicular microsurgical approach with median incision without opening intertransverse fascia is a safe, easy and minimally invasive technique for the surgical treatment of L5-S1 FLLDH.&nbsp;</div>

How I do It: L5/S1 foraminal stenosis and far-lateral lumbar disc herniation with unilateral bi-portal endoscopy.

Surgeries for far-lateral lumbar disc herniation (FLLDH) and foraminal stenosis at the L5/S1 level are very complicated because of its unique structure. The authors have performed unilateral bi-portal endoscopy (UBE) to these lesions because of the good results obtained for other spinal diseases (Park et al. in Orthopedics 40:e779-e783, 2017). We described our experience of the surgical treatment for FLLDH and foraminal stenosis. Useful information for pre-, intraop-, and postoperative care is presented. Among various minimally invasive surgical methods, extraforaminal approaches with UBE can be performed effectively.

Microscopic tubular discectomy for far lateral lumbar disc herniation

Microscopic tubular discectomy (MTD) reduces muscle trauma associated with treatment of far lateral lumbar disc herniation (FLDH), but data from randomised controlled studies concerning its efficacy on posterolateral disc herniation, has failed to demonstrate its superiority over standard open techniques. Importantly concerns have been raised that it may be inferior in terms of relief of leg and back pain. Although several FLDH series show that MTD can deliver excellent outcomes, the volume of literature in this field has remained small and evidence based on health-related quality of life (HRQOL) measures, scarce. In this study we therefore evaluated the role of MTD for FLDH through analysing multiple HRQOL scores collected in a prospective database. We identified 24 patients who underwent MTD through a caudal approach, targeting directly the disc space to minimise traction on the dorsal root ganglion implicated in causing iatrogenic neuralgia. With a mean follow-up of 9.2months, the improvement in Oswestry Disability Index and Short Form 36 physical functioning and bodily pain scores was 32, (95% confidence interval [CI]: 21–43), 40 (95% CI: 30–51) and 35 (95% CI: 26–43) respectively. The improvement on the Visual Analogue Scale was 38mm (95% CI: 23–54) and 35mm (95% CI: 21–48) for leg pain and back pain respectively. There was no postoperative neuralgia noted and no reoperation required. Our data demonstrated clinically meaningful treatment effects and compare favourably with HRQOL surgical outcomes established for posterolateral disc herniation, supporting MTD as a valid treatment option for FLDH.

The Efficacy of Gabapentin in the Treatment of Pain Due to Far Lateral Lumbar Disc Herniations.

Far lateral lumbar disc herniations (FLLDHs) can cause difficulty and differences in diagnosis and treatment compared with intraspinal herniation. We have aimed to analyze the efficacy of gabapentin as a noninvasive treatment of pain in patients with isolated FLLDH. Thirteen patients with isolated FLLDH were evaluated for the study prospectively. All of the cases were diagnosed by lumbar magnetic resonance imaging. The previously prescribed medical therapy of the patients was not changed and gabapentin (3 × 600 mg/d) was added. For each patient, visual analog scale and Odom criteria were administered and recorded at 4 time points as follows: pretreatment and days 1, 7, and 30 posttreatment. Paired t test was used to examine scores of the cases before and after gabapentin treatment. Results were considered significant at P < 0.05, and 95% confidence interval was calculated. Mean visual analog scale score was 9.3 in the pretreatment period, and reduced to 5, 2.6, and 1.3 on posttreatment days 1, 7, and 30, respectively (P < 0.05). Mean Odom criteria score was 4 before gabapentin treatment. It decreased to 2.3 at posttreatment day 1 and 1.5 at day 7. At the end of 1 month, symptoms had resolved completely in all cases (P < 0.05). Gabapentin provided fast and effective relief of pain caused by FLLDH. We advise that the gabapentin should be kept in mind in the first-step medication of pain for such patients. Direct compression of the dorsal root ganglion or its distal part may be related to the intense pain-relief effect provided by gabapentin.

Transforaminal percutaneous endoscopic discectomy in the treatment of far-lateral lumbar disc herniations in children.

The use of transforaminal percutaneous endoscopic discectomy for the treatment of far-lateral lumbar disc herniations has been applied mostly in adults. However, transforaminal percutaneous endoscopic discectomy in children has probably been rarely documented. The aim of this study was to assess the efficacy of transforaminal percutaneous endoscopic discectomy in the treatment of far-lateral lumbar disc herniations in children. Overall, 12 cases of far-lateral lumbar disc herniations were treated with the procedure of transforaminal percutaneous endoscopic discectomy between January 2010 and December 2014. There were seven male and five female children included, with an average age of 12.6years (11-16years). Pre-operative and post-operative (6weeks, 6months and 12months) clinical outcome data (back and leg visual analog scale [VAS] and Macnab criteria) were collected along with clinical assessments of motor strength (graded 0-5). All patients were discharged to home on the same day of surgery. The average leg VAS score improved from 8.6 ± 1.6 to 2.1 ± 0.4 (p < 0.005). Six patients had excellent outcomes, five had good outcomes, one had fair outcomes, and none had poor outcomes, according to the Macnab criteria. Eleven of 12 patients had excellent or good outcomes, for an overall success rate of 91.6%. No patients required re-operation. There were no incidental durotomies, infections, vascular or visceral injuries. There was one complication, a case of leg numbness caused by ganglion injury. The numbness improved after two weeks. After three months, it was obvious that the total area of numbness in the legs had become smaller. At last follow-up, the patient had no pain, and only a few areas with numbness remained and did not affect the patient's activities of daily living. Transforaminal percutaneous endoscopic discectomy achieved satisfactory results for children with far-lateral lumbar disc herniations.

The diagnosis comparative analysis for patients with FLLDH by CT and MRI

Objective To investigate and analyze the diagnostic imaging features of patients with far lateral lumbar disc herniation (FLLDH) by CT and MRI.Methods 38 patients with FLLDH were diagnosed,and its radiology imaging diagnosis and clinical characteristics were analyzed.The main positive results of intervertebral disc herniation segment by CT and MRI scanning and its imaging features were observed.Results The positive of CT scans was 94.74％ (36/38),MRI scans was 100％ (38/38),the difference was not statistically significant (x2 =2.89,P ＞0.05) ;disc segments were mainly in L3-4 and L4-5 segments respectively,MRI scans were 34.21％ (13/38) and 39.47％ (15/38),CT scans were 3 1.58％ (12/38) and 39.47％ (15/38) ;22 cases with hummocky,8 cases with semicircular,irregular triangular shape and 3 cases respectively ;4 cases with foramen medial,18 cases with lateral foramen,14 cases of mixed type;prominence of ＜ 3 mm was 13 cases,20 cases with 4 to 7 mm,8 cases with more than 7mm.Conclusion CT and MRI examination can accurately diagnose FLLDH and judge its location,extent and clinical timely treatment has important clinical application value. Key words: Intervertebral disc displacment ; Tomography, spiral computed ; Magnetic resonance imaging

The surgical treatment of single level multi-focal subarticular and paracentral and/or far-lateral lumbar disc herniations: the single incision full endoscopic approach.

BackgroundSurgery for same level multi-focal extruded lumbar disc herniations is technically challenging and the optimal method controversial. The subarticular disc herniation may pose the most challenging subtype requiring partial or complete facetectomy with or without fusion. The far-lateral disc herniation, often treated using a Wiltse approach, can also be difficult to access especially in the obese patient. When both the subarticular and far-lateral subtypes are simultaneously present at the same level with or without a paracentral disc herniation, a total facetectomy and interbody fusion (TLIF) or a total disc replacement (TDR) may be necessary. Endoscopic surgical techniques may reduce the need for these more invasive methods.MethodsFifteen patients (6 male and 9 female) who had same level multi-focal (subarticular as well as far-lateral and/or paracentral) extruded disc herniations underwent single incision unilateral endoscopic disc excision by the same surgeon at a single institution. Patients were prospectively followed for an average of 15.3 months (range 14-18 months) and outcomes were evaluated radiographically and clinically (Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI).ResultsThe mean operative time was 52 minutes with minimal blood loss in all cases. Fourteen of the 15 patients were discharged to home on the day of their surgery. The mean ODI and leg VAS scores improved from 22.9 ± 3.2 to 12.9 ± 2.7 (p < 0.005), and from 8.6 ± 1.6 to 2.1 + 0.4 (p < 0.005), respectively.ConclusionsAfter an average of 15.3 months of follow-up, the clinical and radiographic results of full endoscopic surgical treatment of single level multi-focal (subarticular as well as far-lateral and/or paracentral) disc herniations are excellent. This study is a case series with mid-term follow-up (Level IV).Clinical RelevanceForaminal and extra-foraminal full endoscopic decompression appears to offer a safe minimally invasive solution to a complex pathologic problem.

The usefulness of magnetic resonance imaging for sequestered lumbar disc herniation treated with endoscopic surgery

Forty two patients with sequestered lumbar intervertebral disc herniation were treated by endoscopic surgery with the mobile Endospine system. The herniations and migration were confirmed on magnetic resonance imaging (MRI). The interlamina fenestration and pars interarticularis fenestration approaches were used for intracanal herniations and far lateral lumbar disc herniations (FLLDH) according to the degree of migration as observed on MRI. Sequestered herniations were exposed and removed completely with the mobile endoscopic system for all patients without neurologic complications or dural tears. Intraoperative findings were compared with preoperative MRI results. Of 24 caudal intracanal herniations, 15 had sequestered nuclei located ventrally beneath the dural theca and the transverse nerve root; 5 were between the transverse nerve root and dural theca (axillary); 4 were dorsally located on the nerve root and dural theca. However, preoperative MRI did not clearly display the sequestered nuclei between the transverse nerve root and dural theca (axillary), or the dorsally migrated disc on the nerve root and dural theca. Of 6 cranial intracanal herniations, 5 had free fragments located beneath the dural theca, and 1 dorsal to the dural sac. Of the 2 dorsal herniations, the migrated nucleus adhered to the dural sac was not found on preoperative MRI; in the other case, dorsal migration of nucleus, annulus and endplate around the dural sac was also not observed on preoperative MRI. Among the 10 FLLDH, preoperative MRI showed cranial migration and foraminal obstruction in all patients, with sequestered disc material at the ventral and medial sides of the exiting nerve root, displacing the exiting nerve root and ganglion cranially and dorsally. During the 12 to 48 month postoperative follow-up period, 26 patients had excellent clinical results and 15 patients had good results (Macnab scale). In conclusion, MRI is important for evaluating sequestered lumbar disc herniation, although it has its limitations. Sequestered herniations can be exposed and removed completely with the mobile endoscopic system.

Utility of Direct Stimulation of Roots in Spinal Surgery

Prevention of postoperative neurological deficits is a major concern of spinal surgeons and has led to the introduction and current development of intraoperative neurophysiological monitoring. We have used motor evoked potentials and somatosensory evoked potentials as routine monitoring techniques and, in some cases, added optional methods such as direct stimulation of nerve roots and spinal evoked potentials. We report our experience of direct nerve root stimulation as an optional monitoring method during spinal surgeries in 7 patients with lesions affecting the proximal nerve roots aged from 1 day to 78 years (mean 23.5 years). Four patients had anomalous lesions, two had spinal nerve root schwannomas, and one had a far-lateral lumbar disc herniation. Direct stimulation was used for detection of motor nerve roots in the anomalous lesions and schwannomas, and to distinguish the nerve root from the paraspinal soft tissues in the case of a far-lateral herniated disc at the L5-S1 level. Although some patients had slight transient neurological symptoms such as motor weakness and sensory disturbance, none developed severe permanent neurological impairment. Direct stimulation allows detection of the motor nerve during spinal surgery in real time. Our limited experience suggests that the direct stimulation technique could reduce the risk of motor or vesicorectal disturbance after surgery of lesions affecting or involving the spinal nerve roots.

Unilateral pedicle screw fixation plus interbody fusion by Quadrant system through spatium intermuscular of multifidus

To explore the clinical outcome of unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus by Quadrant system. From April 2008 to April 2009, 47 patients underwent unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus. There were 22 males and 25 females with the mean age of 58.2 years (range, 46-74 years). Among them 12 cases had far-lateral lumbar disc herniation, 7 cases had post-discectomy recurrence, and 28 cases had degenerative instability. Thirty-seven cases were treated with lumbar interbody fusion through transforaminal approach, 10 cases through posterior approach. After surgery, the radiography was carried out to demonstrate the fusion status, and the Nakai criterion was used for assessment. The average skin incision length was 3.2 cm (range, 3.0 to 3.5 cm), the average operative time was 90 min (range, 70 to 160 min), and the average blood loss was 130 ml (range, 90 to 360 ml). All cases were followed up for 8 - 20 months (average 13.6 months). Postoperative radiography showed no evidence of instrument failure, and 43 cases got bone fusion, 4 cases got suspicious fusion. At final followed-up the average leg pain VAS decreased from 7.4 ± 1.1 preoperatively to 2.4 ± 1.3 postoperatively, the average low back pain VAS decreased from 6.7 ± 1.3 preoperatively to 1.8 ± 1.5 postoperatively. According to Nakai criterion, 31 cases were rated as excellent, 11 cases as good, and 5 cases as fair with the total excellent and good rate of 89.4%. Unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus has some advantages of minimal invasiveness, less blood loss, less complications and reliable curative effect. It is a satisfactory lumbar fusion method under suitable indication.

Extreme-lateral, minimally invasive, transpsoas approach for the treatment of far-lateral lumbar disc herniation

The authors present 2 cases of far-lateral lumbar disc herniations treated surgically via an extreme-lateral transpsoas approach. The procedure was performed using the MaXcess minimally invasive retractor system to access and successfully remove the disc fragments without complication. To the authors' knowledge, these are the first reported cases of using a minimally invasive retroperitoneal approach for the treatment of far-lateral disc herniations.