Diagnosis and microsurgical approach to far-lateral disc herniation in the lumbar spine

Comparative Analysis on Surgical Operability and Degree of Exposure of Microsurgical Approaches to Intraforaminal Lumbar Disk Herniations

BACKGROUND

 Intraforaminal lumbar disk herniations (IFDHs) represent a heterogeneous and relatively uncommon disease; their treatment is technically demanding due to the anatomical relationships with nerve roots and vertebral joints. Over time, several approaches have been developed without reaching a consensus about the best treatment strategy.

MATERIALS AND METHODS

 Authors comparatively analyze surgical operability and exposure in terms of quantitative variables between the different microsurgical approaches to IFDHs, defining the impact of each approach on surgical maneuverability and exposure on specific targets.A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability.

RESULTS

 Transarticular and combined translaminar-trans-pars-interarticularis approaches result in providing the best surgical exposure and maneuverability on all targets with surgical controls on both nerve roots, at the expense of a higher risk of iatrogenic instability. Trans-pars-interarticularis approach reaches comparable levels of operability, even limited to the pure foraminal area (lateral compartment); similar findings were recorded for partial facetectomy on the medial compartment. The contralateral interlaminar approach provides good visualization of the foramen without consensual favorable maneuverability, which should be considered the main drawback.

CONCLUSIONS

 Approach selection has to consider disease location, the possible migration of disk fragments, the degree of nerve root involvement, and risk of iatrogenic instability. According to the findings, authors propose an operative algorithm to tailor the surgical strategy, based both on the precise definition of anatomic boundaries of exposure of each approach and on surgical maneuverability on specific targets.

Minimally Invasive Far Lateral Lumbar Discectomy With Modified Technique: Symptomatic Relief and Intersegmental Stability Study

OBJECTIVE

To evaluate the use of a modified minimally invasive surgery (MIS) technique for far lateral lumbar discectomy (FLDH) that minimizes the degree of bony drilling required for nerve root decompression, increasing postoperative pain reduction rate with reduced risk of iatrogenic spinal instability.

SUMMARY OF BACKGROUND DATA

FLDH accounts for approximately 10% of all lumbar disc herniations and is increasingly recognized in the era of advanced imaging techniques. These disc herniations typically result in extra-foraminal nerve root compression. Minimally invasive spine techniques are increasingly performed with various degrees of foraminal and facet removal to decompress the affected nerve root.

METHODS

The study design involves a single institutional, retrospective cohort technical review. The review was completed of all patients undergoing MIS far lateral lumbar discectomy between 2010 and 2020. Cross-sectional, summary statistics were calculated for all variables. Counts and percentages were recorded for categorical variables and mean and standard deviations were calculated for continuous variables.

RESULTS

A total of 48 patients underwent MIS far lateral lumbar discectomies (FLLD) from 2010 to 2020. The mean age was 63 ± 11.5 years (60.4% males), the mean BMI was 28.5 ± 5.5, and 20.8% smokers. The most common presenting complaint was both low back and radicular pain (79.2%) with 8.3% of patients suffering from motor weakness preoperatively. The mean follow-up time was 4.3 ± 2.7. The mean length of stay was 1.3 ± 1.4 days with 77.1% of patients discharged postoperative day one. Forty-three patients (93.5%) had improvement in their symptoms. Twenty-seven (58.7%) had complete resolution in 2.6 months on average. Six patients (13%) had immediate symptom resolution postoperatively.

CONCLUSIONS

Our modified technique for FLLD allows MIS access to the extra-foraminal site of nerve root compression without the need for bony drilling. This minimizes postoperative pain and reduces the risk of iatrogenic spinal instability without sacrificing symptom resolution.

Spinal Injections: A Narrative Review from a Surgeon's Perspective

Spinal pain is one of most frequent complaints of the general population, which can cause decreased activities of daily living and absence from work. Among numerous therapeutic methods, spinal injection is one of the most effective treatments for spinal pain and is currently widely applied in the clinical field. In this review, spinal injection is discussed from a surgeon's perspective. Recently, although the number of spinal surgeries has been increasing, questions are arising as to whether they are necessary. The failure rate after spinal surgery is high, and its long-term outcome was reported to be similar to spinal injection. Thus, spinal surgeries should be performed conservatively. Spinal injection is largely divided into diagnostic and therapeutic blocks. Using diagnostic blocks, such as the diagnostic selective nerve root block, disc stimulation test, and diagnostic medial branch block (MBB), the precise location causing the pain can be confirmed. For therapeutic blocks, transforaminal nerve root injection, therapeutic MBB, and percutaneous epidural neuroplasty are used. When unbearable spinal pain persists despite therapeutic spinal injections, spinal surgeries can be considered. Spinal injection is usefully used to identify the precise location prior to a patient undergoing injection treatment or surgery and can reduce pain and improve quality of life, and help to avoid spinal surgery. Pain physicians should treat patients with spinal pain by properly utilizing spinal injection.

Biportal endoscopic paraspinal decompressive foraminotomy for lumbar foraminal stenosis: clinical outcomes and factors influencing unsatisfactory outcomes

BACKGROUND

Lumbar foraminal stenosis (LFS) is an important pathologic entity that causes lumbar radiculopathies. Unrecognized LFS may be associated with surgical failure, and LFS remains challenging to treat surgically. This retrospective cohort study aimed to evaluate the clinical outcomes and prognostic factors of decompressive foraminotomy performed using the biportal endoscopic paraspinal approach for LFS.

METHODS

A total of 102 consecutive patients with single-level unilateral LFS who underwent biportal endoscopic paraspinal decompressive foraminotomy were included. We evaluated the Visual Analogue Scale (VAS) score and the Oswestry Disability Index (ODI) before and after surgery. Demographic, preoperative data, and radiologic parameters, including the coronal root angle (CRA), were investigated. The patients were divided into Group A (satisfaction group) and Group B (unsatisfaction group). Parameters were compared between these two groups to identify the factors influencing unsatisfactory outcomes.

RESULTS

In Group A (78.8% of patients), VAS and ODI scores significantly improved after biportal endoscopic paraspinal decompressive foraminotomy (p < 0.001). However, Group B (21.2% of patients) showed higher incidences of stenosis at the lower lumbar level (p = 0.009), wide segmental lordosis (p = 0.021), and narrow ipsilateral CRA (p = 0.009). In the logistic regression analysis, lower lumbar level (OR = 13.82, 95% CI: 1.33-143.48, p = 0.028) and narrow ipsilateral CRA (OR = 0.92, 95% CI: 0.86-1.00, p = 0.047) were associated with unsatisfactory outcomes.

CONCLUSIONS

Significant improvement in clinical outcomes was observed for a year after biportal endoscopic paraspinal decompressive foraminotomy. However, clinical outcomes were unsatisfactory in 21.2% of patients, and lower lumbar level and narrow ipsilateral CRA were independent risk factors for unsatisfactory outcomes.

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 prevent but may delay the surgery up to 28 months. Although postoperative pain scores were significantly decreased, there was persistent back pain and sensory paresthesia.

Extra-laminar microscopic-assisted percutaneous nucleotomy (EL-MAPN) for the treatment of foraminal lumbar disc prolapse, a modified minimally invasive approach

PURPOSE

In this work, a modification of the percutaneous surgical approach for removing the lumbar foraminal disc prolapse is introduced.

MATERIAL AND METHODS

A prospective study was performed. The indication for surgery was foraminal disc prolapse presenting with acute motor or persistent sensory radiculopathy. MRI and X-ray of the lumbar spine were performed. VAS and ODI were recorded. The operation was done under general anesthesia. A needle was inserted for level-localization using C-arm. A 1.5 cm para-median skin incision was performed. A gradual dilatation using trocars was followed by the insertion of a tubular system. Under direct vision using the operative microscope, the lateral edge of the lamina was identified. A small, hooked probe was inserted in the foramen, and its position was documented fluoroscopically. With the help of the microscope, the triad consisting of Pedicle, Nerve root, and Prolapse "PNP" was identified. The nerve root was mobilized, and the prolapsed disc was removed.

RESULTS

The study included 50 patients, 26 females, and 24 males. The mean follow-up was 18 months. The mean operative time was 65 min. The mean blood loss was 105 ml. The mean VAS improved from 7.8 ± 2.3 preoperatively to 0.8 ± 0.3 after one year (p = 0.001). Mean ODI improved from 28 ± 10.4 to 4 ± 2.3 after one year (p = 0.02). A recurrent disc occurred in 2 patients and was revised in the same technique.

CONCLUSION

EL-MAPN represents a minimally invasive approach for foraminal disc prolapse removal under direct visual control avoiding injury to the facet joint or pars interarticularis.

The irony of the transforaminal approach: A comparative cohort study of transforaminal endoscopic lumbar discectomy for foraminal versus paramedian lumbar disc herniation

Transforaminal endoscopic lumbar discectomy (TELD) is useful for soft lumbar disc herniation (LDH). Although the transforaminal approach can reach the foraminal disc zone, the risk of exiting nerve root irritation along the path is considerable. Few studies have assessed the difficulties of TELD for foraminal LDH. The objective of this study is to compare the clinical results of TELD between foraminal or far-lateral LDH and paramedian LDH.Between June 2016 and July 2017, 135 consecutive patients with single-level LDH were treated with TELD for 2 years. Among them, 25 patients had foraminal or far-lateral LDH (foraminal group), and the remaining 110 patients had central or subarticular LDH (paramedian group). Perioperative data and clinical outcomes were evaluated using the visual analog pain scale, Oswestry Disability Index, and modified Macnab criteria.The foraminal group showed a higher rate of significant access pain (24.00% vs 8.19%, P < .05). The foraminal group also had a longer duration of surgery, length of hospital stay, and return to work (all P < .05). Pain scores and functional status were significantly improved in both groups. Although there were no differences in the outcomes at 2 years postoperatively, early pain and disability at 6 weeks were higher in the foraminal group.Ironically, the early clinical results of TELD for foraminal LDH may be less favorable than those for paramedian LDH. Therefore, great care should be taken during TELD for foraminal or far-lateral LDH.

Surgical Outcomes of Extraforaminal Microdiskectomy by Midline Incision for Far-Lateral Lumbar Disk Herniation

BACKGROUND

 Far-lateral lumbar disk herniation (FLDH) is defined as a disk herniation located laterally to the medial wall of the pedicle. The aim of our study is to describe the extraforaminal microdiskectomy by midline incision for FLDH, which does not include laminotomy-partial facetectomy, and to evaluate mid-term surgical outcomes.

METHODS

 107 patients who underwent surgery for FLDH by midline incision for the first time between 2012 and 2017 were included in our study. The assessment of neurological status of the patients was done by physical examination, preoperative Oswestry Disability Index (ODI), Visual Analog Scala (VAS) scores, and magnetic resonance images. They were then followed-up postoperatively and at 12 months with VAS and ODI tests.

RESULT

 58 (54.2%) patients were male and 49 (45.8%) were female. The mean age at the time of surgery was 55.0 ± 8.6 years. The mean ODI scale score was 32.4 ± 6.2 preoperatively, 11.4 ± 2.1 early postoperatively, and 9.7 ± 2.2 in late postoperative follow-up (statistically significant, p = 0.001). The average VAS was 7.51 ± 1.1 preoperatively, 2.74 ± 0.7 early postoperatively, and 0.68 ± 0.08 in late postoperative follow-up (statistically significant, p = 0.001). The average operative time was 41 ± 7 (37 to 58) minutes.

CONCLUSIONS

 The extraforaminal microdiskectomy without laminotomy by midline incision is a minimally invasive approach for FLDH. Our technique allows a sufficient and safe decompression of the neural structures, and thus results in a significant reduction of the symptoms and disability.

Clinical Presentation and Outcomes of Patients With a Lumbar Far Lateral Herniated Nucleus Pulposus as Compared to Those With a Central or Paracentral Herniation

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Examine pre- and postoperative outcomes between patients presenting with a central/paracentral versus a far lateral herniated nucleus pulposus (HNP) and assess whether significantly worse postoperative outcomes, assessed via patient self-reported survey, are associated with far lateral disc herniations.

METHODS

We performed a retrospective cohort analysis of patients who underwent primary lumbar decompression between January 2008 and December 2015. Groups were divided based on herniation type, central/paracentral or far lateral. Patients with 3 months, or longer, of follow-up were included. Variables analyzed included demographics, American Society of Anesthesiologists (ASA) Score, Charleston Comorbidity Index (CCI), Oswestry Disability Index (ODI) scores, Visual Analog Scales (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey (SF-12) scores, and Veterans RAND 12-Item Mental and Physical Survey (VR-12) scores.

RESULTS

A total of 100 patients met the inclusion criteria. Postoperative ODI scores for central/paracentral HNP were significantly lower compared to far lateral HNP. Patients with a far lateral disc herniation presented with significantly lower preoperative SF-12 and VR-12 scores. The improvement in ODI score from preoperative to final was significantly lower in the patients presenting with a far lateral HNP.

CONCLUSIONS

Although patients with far lateral HNP present with worse preoperative outcome scores, they can expect similar symptom improvement to central or paracentral herniations following discectomy. This information can be used for future surgeons when weighing conservative versus surgical treatment of far lateral herniations.

Laser-Assisted Microdiscectomy for Far Lateral Lumbar Disc Herniation at the L5-S1 Level

OBJECTIVE

Laser-assisted paraspinal microdiscectomy for far lateral lumbar disc herniation (LDH) enables direct access to the foraminal or far lateral zone with minimal tissue injury and preserves facet joints, thereby preventing postoperative segmental instability. We demonstrated the clinical outcomes of this technique and discussed the pros and cons of laser use in lumbar disc surgery.

BACKGROUND

The microdiscectomy technique for L5-S1 far lateral zone may be difficult due to the limited surgical field with narrowed disc space, hypertrophied facet, and sacral ala. Thus, we used carbon dioxide (CO₂) laser for sophisticated decompression.

METHODS

Eighty-four patients who were treated with microdiscectomy for far lateral LDH at the L5-S1 level were evaluated. Among them, 40 patients were treated using CO₂ laser-assisted microdiscectomy, and the remaining 44 patients using conventional microdiscectomy. Perioperative and postoperative data were compared between the two groups with 2 years of follow-up. Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry disability index (ODI), and modified Macnab criteria.

RESULTS

VAS and ODI significantly improved in both groups. An excellent or good outcome was rated in 80% and 77.3% of the laser and conventional group, respectively. There was no significant difference in global outcomes. However, hospital stay and time to return to work were significantly shorter in the laser group (p < 0.05).

CONCLUSIONS

CO₂ laser-assisted paraspinal microdiscectomy is effective for treating far lateral LDH. The pinpoint laser scalpel enables delicate and complete decompression in a limited surgical field with minimal tissue trauma.

Surgical treatment of intraforaminal/extraforaminal lumbar disc herniations: Many approaches for few surgical routes

BACKGROUND

Several disc disease nomenclatures and approaches for LDH exist. The traditional midline bone-destructive procedures together with approaches requiring extreme muscular retraction are being replaced by muscle sparing, targeted, stability-preserving surgical routes. The increasing speculation on LDHs and the innovative corridors described to treat them have lead to an extensive production of papers frequently treating the same topic but adopting different terminologies and reporting contradictory results.

METHODS

The review of such literature somehow confounding gave us the chance to regroup by surgical corridors the vast amount of approaches for LDH differently renamed over time. Likewise, LDHs were simplified in intra-foraminal (ILDH), extra-foraminal (ELDH), and intra-/extra-foraminal (IELDH) in relation to precise anatomical boundaries and extent of bulging disc.

RESULTS

Through the analysis of the papers, it was possible to identify ideal surgical corridors for ILDHs, ELDHs, and IELDHs, distinguishing for each approach the exposure provided and the technical advantages/disadvantages in terms of muscle trauma, biomechanical stability, and nerve root preservation. A significant disproportion was noted between studies discussing traditional midline approaches or variants of the posterolateral route and those investigating pros and cons of simple or combined alternative corridors. Although rarely discussed, these latter represent valuable strategies particularly for the challenging IELDHs, thanks to the optimal compromise between herniation exposure and bone-muscle preservation.

CONCLUSIONS

The integration of adequate mastery of traditional approaches together with a greater confidence through unfamiliar surgical corridors can improve the development of combined mini-invasive procedures, which seem promising for future targeted LDH excisions.

Transpars Microscopic Approach for the Treatment of Purely Foraminal Herniated Lumbar Disc: A Clinical, Radiological, Two-center Study

STUDY DESIGN

This is a prospective two-center study.

OBJECTIVE

The aim of this study was to assess the safety and efficacy of treating patients with lumbar foraminal disc herniations via a microscopic transpars approach, with a clinical and radiological follow-up evaluation.

SUMMARY OF BACKGROUND DATA

Purely foraminal lumbar disc herniations comprise about 5% of all lumbar herniated intervertebral discs. Operative management can be technically difficult, and the optimum surgical treatment remains controversial.

METHODS

From January 2012 to January 2015, 47 patients were prospectively recruited. Patients were followed-up as outpatients at 1 week after discharge, then at 1, 6, and 12 months.A clinical multiparametric evaluation of patients including numeric rating scale (NRS), drugs intake, Macnab criteria, and working days lost was used.Postoperative dynamic x-rays (flexion, extension) were performed in all cases 12 months after surgery.

RESULTS

No surgery-related complications occurred.Among the 35 patients who were not retired at the time of the study, 29 patients returned to work and to normal daily activities within 60 days after surgery.Pain evaluation at discharge showed a significant improvement of NRS score, from 8.93 to 1.45 at 12 months. Root palsy significantly improved in all cases already at 1-month follow-up. Drugs intake analysis showed that at 6-month follow-up, no patients used steroids, or opioids, 17 patients used non-steroidal anti-inflammatory drugs when needed, and 29 patients (61.7%) used no drugs for pain relief. No significant variations occurred at 12-month-follow-up.At 12-month follow-up, excellent or good outcome (following Macnab criteria) was achieved in 36 (76.6%) and 8 (17%) patients, respectively.There were no cases of spinal instability at 12-month radiological evaluation.No recurrence occurred at follow-up.

CONCLUSION

Transpars microscopic approach is effective and safe for the treatment of FLDH, but larger studies are needed.

LEVEL OF EVIDENCE

3.

Extraforaminal Disk Herniation Treatment with Surgical Exploration by Unilateral Intertransversarii Microsurgical Approach

BACKGROUND

In this study we evaluated the role of a unilateral intertransversarii microsurgical approach for the treatment of extraforaminal lumbar disk herniations (ELDHs), with short-, medium-, and long-term follow-up.

METHODS

We retrospectively evaluated 96 patients who had undergone surgery for ELDH between 2001 and 2012 at our Institution. All the patients had been examined before the intervention, immediately after, and at 6 weeks, 6 months, and 18 months after the intervention. All the patients underwent surgical exploration with a unilateral intertransversarii microsurgical approach. After a midline incision was made, the paraspinal muscles were retracted laterally up to the transverse process, in order to visualize the intertransversarii ligament. Removal of this ligament allows microsurgical exposure of the extraforaminal pathology. If necessary, interlaminar microsurgical exploration is performed in the same session.

RESULTS

At 6-week postoperative follow-up we noted a significant decrease of pain both in patients who suffered from leg pain and in patients who reported back pain. Also, sensory and motor deficits had improved considerably. At 6-month postoperative follow-up we observed a further improvement in the clinical conditions of almost all patients. At the 18-month postoperative follow-up we observed a very low incidence of relapse of neurological symptoms.

CONCLUSION

Our technique can be reasonably proposed because of its low morbidity, fast recovery, and short hospital stay.

Three-Years Outcome of Microdiscectomy via Paramedian Approach for Lumbar Foraminal or Extraforaminal Disc Herniations in Elderly Patients over 65 Years Old

OBJECTIVE

Lumbar foraminal or extraforaminal disc herniations (FEFDH) have unusual clinical features and higher incidence in elderly patients compared to usual intraspinal canal disc herniations. We evaluated the efficacy of microdiscectomy via paramedian approach for lumbar FEFDH in elderly patients over the age of 65.

METHODS

Retrospective study was performed in 68 patients over the age of 65 (23 male and 45 female patients; 71.46±3.87 years) who underwent microdiscectomy via paramedian approach for unilateral lumbar FEFDH causing sciatica. The radiological factors including degree of slippage, presence of instability, disc height, and degree of disc degeneration; pain and functional status by the means of visual analogue scale score, Oswestry Disability Index score, and Macnab classification were analyzed preoperatively and during the postoperative follow-up period of 3 years to evaluate the efficacy of the surgical treatment.

RESULTS

Pain and functional status improved according to short- and long-term follow-up evaluations after surgery. Radiological changes following surgery, which can be understood as structural deteriorations and deformations, did not represent patient condition. Nine patients underwent additional surgery due to sustained or recurring leg pain of aggravation of back pain, and fusion surgery was required for 3 patients. Degree of preoperative slippage was the only statistically significant factor related to additional surgery (p<0.05).

CONCLUSION

Microdiscectomy via paramedian approach for FEFDH may be a good surgical alternative in elderly patients. Radiological changes after surgery did not show a concordance with patients' actual functional status. The excessive preoperative slippage tended to lead to unfavorable result after surgery and was associated with additional surgery.

Surgical treatment of far lateral lumbar disc herniation: a safe and simple approach

Lumbar discectomy is one of the most commonly performed neurosurgical procedure. Far lateral disc herniations (FLDH) make up a minor portion of the total discectomy workload for spine surgeons. Due to their lower incidence, as well as their different anatomical positioning compared to the more common para-median disc herniation, the surgical procedures involved in releasing the neural compression caused by FLDHs are often challenging and at times frustrating to most spine surgeons, resulting in suboptimal outcomes for the patient related to the higher risk of spinal instability from facet joint disruption and may even be associated with nerve root injury. We discuss here a safe and simple approach to tackle FLDH.

Evaluation of the origin and branching patterns of the iliolumbar artery and its implications on pelvic and vertebral surgery

Objectives:

To evaluate the origin, distribution pattern, branches, and neighboring structures of the iliolumbar artery (ILA) concerning the anterolateral surgical approaches to the spine.

Methods:

This study was performed in the Anatomy Department of Medical School, Mersin University, Mersin, Turkey between 2014 and 2015. Pelvises of 11 male formalin-fixed human cadavers were dissected by anterior and posterior approaches under surgical microscope. The origins, distribution patterns, calibers, and distances to certain structures were measured.

Results:

The ILA was found as a single trunk on 17 sides arising either from the IIA (12 sides, 70.6%) or the PT (5 sides, 29.4%). The average caliber of those originated from the posterior trunk was significantly larger (p=0.010). The ILA started as a single trunk in 17 sides, while its lumbar and iliac branches separately originating from different arteries in 4 sides. The close relation of the posterior rami of both the lumbar and iliac branches with transverse process and spinal nerve were noted.

Conclusion:

Findings suggest that the ILA and its branches may have different and significant patterns, which may be crucial to consider during certain surgical procedures, such as far lateral disc herniation and posterior pelvic fixations.

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.

The Comparisons of Surgical Outcomes and Clinical Characteristics between the Far Lateral Lumbar Disc Herniations and the Paramedian Lumbar Disc Herniations

Objective

The purpose of this study is to analyze clinical characteristics and surgical outcomes of the far lateral and the paramedian disc herniations.

Methods

The 88 patients who underwent an operation for lumbar disc herniations were reviewed. Visual analogue scale of leg and back pain, occurrence of sensory dysesthesia and motor deficit before and after operations were used to compare the far lateral with the paramedian disc herniations.

Results

Statistically, the far lateral herniations had more severe radicular leg pain and showed more frequent occurrence of sensory dysesthesia than paramedian herniations before operation (p<0.05). In the far lateral herniation group, preoperatively, 15 patients (75%) had sensory dysesthesia and among them, 4 patients (27%) showed improvement. In the paramedian herniation group, preoperatively, 25 patients (37%) had sensory dysesthesia and among them, 21 patients (84%) showed improvement. The degree of improvement in sensory dysesthesia was statistically higher in paramedian herniation group (p<0.05). In the far lateral herniation group, preoperatively, 11 patients (55%) had motor deficit and among them, 10 patients (91%) showed improvement. In the paramedian herniations, preoperatively, 29 patients (43%) had motor deficit and among them, 25 patients (86%) showed improvement. The degree of improvement in motor deficit was not statistically significant between groups (p>0.05).

Conclusion

Preoperatively, the far lateral herniations had more severe radicular leg pain and frequent occurrence of sensory dysesthesia. Postoperatively, the sensory dysesthesia was less improved and back pain was more severe in the far lateral herniations.

Lumbar extraforaminal decompression: A technical note and retrospective study looking at potential complications as an outpatient procedure

BACKGROUND

Lumbar disc herniation and stenosis that results in compression of a nerve root lateral to the foramen is defined as extraforaminal. In recent years the recognition of such pathology has increased with technology and greater awareness. Various approaches and techniques have been developed for extraforaminal decompression in the lumbar region. The purpose of this study was two fold: 1) Determine the safety of treating patients operatively via a paramedian muscle splitting approach on an outpatient basis, and 2) Highlight the technical aspects of the approach to the extraforaminal region.

METHODS

One hundred consecutive extraforaminal decompressions were performed from 1992 to 2007 by a single surgeon. A retrospective review was performed consisting of chart reviews. Summary statistics and the Pierson Chi-square test were used to analyze the data. The primary outcome measure was the need for hospital admission or readmission following surgical decompression.

RESULTS

Seven of 100 patients (7%) were required to remain in the hospital for twenty-three hour observation due to Medicare requirements. Five (5%) of the patients originally scheduled for an outpatient procedure were converted to inpatient status due to postoperative pain. All were released within 2 days (average 1.25 days). Only one (1%) patient was readmitted for urinary retention that resolved without incident. There was no significant difference (P = 0.137) in complication rate between our control and those that underwent extraforaminal decompression.

CONCLUSIONS

Extraforaminal lumbar decompression as an outpatient procedure can be done safely without the need for hospital admission.

Extreme lateral lumbar disc herniation in a 12-year child: case report and review of the literature

Extreme lateral lumbar disc herniations (ELLDHs) occur more frequently among elderly patients, with a peak incidence in the sixth decade, and are rarely found in children. The patient presented is a 12-year-old boy with a 3-month history of right-sided leg pain. Computerized tomography and magnetic resonance imaging demonstrated an extreme lateral disc herniation on the right at L4-L5 with compression of the L4 nerve root. He subsequently underwent removal of extreme lateral herniated disc through an intertransverse approach under general anesthesia. At 11-month follow-up, the patient maintained resolution of preoperative symptoms and a neurological examination revealed no sensory or motor deficit. Surgical intervention may be indicated for patients with ELLDHs that fail with conservative treatment.

An Unusual Case of Footdrop

OBJECTIVE

Extreme lateral disc herniations are described. Usually, the herniated disc is described as being at the lateral edge of the neural foramen. Herniated discs that lodge beyond this location need to be included in the differential of retroperitoneal lesions impinging on nerve roots.

CLINICAL PRESENTATION

A 76-year-old woman presented with left leg radicular symptoms, including footdrop and a retroperitoneal lesion. Given the location of the lesion and its distance from the edge of the neural foramen, the differential diagnosis favored a nerve sheath tumor.

INTERVENTION

An anterior retroperitoneal approach was taken. At the time of surgery, the lesion proved to be a herniated disc arising from the anterior surface of the L5-S1 disc space, medial to the psoas muscle. The disc herniation resulted in severe compression of the L5 nerve root as the root joined the lumbosacral plexus. This type of even more extreme lateral disc herniation is not widely reported. At this location, there are reports of clinicians confusing discs for tumors and occasionally tumors for discs. Given that some disc herniations are no longer visually adjacent to the foramen, perhaps extreme lateral disc herniation is not an ideal term. This individual case report is supplemented with a review of the literature on this rare condition with specific searches for disc, retroperitoneal, anterior herniation.

CONCLUSION

Using the term anterior disc herniation will aid clinicians in including herniated disc fragments in the differential diagnosis for lesions affecting nerve roots anterior to the spine in this retroperitoneal location.

Herniated nucleus pulposus in isthmic spondylolisthesis: higher incidence of foraminal and extraforaminal types

BACKGROUND

The purpose of this study was to evaluate the pattern of disc herniation and to investigate the associated symptoms in cases of isthmic spondylolisthesis. It is well known that the pathogenesis of degenerative spondylolisthesis associates with disc degeneration, followed by facet laxity and ligamentum flavum hypertrophy, which result in severe spinal canal stenosis. But isthmic spondylolisthesis is known to have a different pathogenesis. In isthmic spondylolisthesis, pseudodisc bulging is easily identified, and canal stenosis is comparatively rare. Therefore, we propose that isthmic spondylolisthesis has a different pattern of disc herniation from degenerative spondylolisthesis. We studied the type, incidence of disc herniation and clinical symptoms related to isthmic spondylolisthesis.

METHOD

This study included 132 patients with isthmic spondylolisthesis who had undergone an operation in the last 4 years. Among them, 120 patients were retrospectively reviewed. The mean age was 49.6 years, and the sex ratio was 1 to 1.93 (male to female). The disc herniation type was identified according to the classification of Bonneville.

FINDINGS

There were 78 patients (65%) with L4 to L5 spondylolisthesis and 42 patients (35%) with L5 to S1 spondylolisthesis. Eighty-two patients (68.3%) had only pseudodisc bulging without disc herniation, and 38 patients (31.7%) had pseudodisc bulging with disc herniation. Among the 38 patients with disc herniation, there were: medial type: 1 patient (2.6%), medial + posterolateral type: 1 patient (2.6%), posterolateral + foraminal type: 2 patients (5.3%), foraminal type: 7 patients (18.4%), foraminal + extraforaminal type: 25 patients (65.8%) and extraforaminal type: 2 patients (5.8%). Overall extreme lateral disc herniation (foraminal, extraforaminal) was seen in 36 patients, which was 30% of the total isthmic spondylolisthesis cases. In 26 out of 36 patients (72.2%), the dermatome was matched to the exact location of the extreme lateral disc herniation. In all cases, the extreme lateral disc herniation migrated upward slightly, about one slice (2 mm) according to thin-cut CT.

CONCLUSIONS

As expected, pseudodisc bulging without disc herniation was the most common type in isthmic spondylolisthesis. However, in cases of disc herniation, extreme lateral disc herniation occasionally occurs; therefore, every isthmic spondylolisthesis patient should be examined carefully for extreme lateral disc herniation with thin-cut axial CT or MRI, especially when the patients complain of lateralizing symptom.

Reliability of MRI findings for Symptomatic Extraforaminal Disc Herniation in Lumbar Spine

STUDY DESIGN

A retrospective study

PURPOSE

This study examined the reliability of the MRI findings in detecting symptomatic extraforaminal disc herniation in the lumbar spine.

OVERVIEW OF LITERATURE

There are no reports of the characteristics and reliable MRI findings of extraforaminal disc herniation.

METHODS

Thirty age-and gender-matched asymptomatic volunteers and 30 patients with symptomatic extraforaminal disc herniation, who underwent surgery between March 2006 and Dec 2008, were enrolled in this study. All subjects underwent spinal MRI. The following parameters were evaluated: the presence or absence of focal eccentricity of the disc, change in the diameter of the nerve root, and displacement of the nerve root at the extraforaminal zones. Radiologic studies were reviewed blindly and independently by 3 spine surgeons.

RESULTS

The overall agreement in determining the presence or absence of a symptomatic extraforaminal disc herniation between the three reviewers was 89.4% (161/180). The consensus showed focal eccentricity of the disc in 33 cases (55%), a change in diameter in the nerve root in 31 cases (51.7%), and a displacement of the nerve root in 23 cases (38.3%). An assessment of the paired intraobserver and interobserver reliability revealed mean Kappa statistics of 0.833 and 0.667 for focal eccentricity of the disc, 0.656 and 0.556 for a change in the diameter of the nerve root, and 0.669 and 0.020 for a displacement of the nerve root, respectively.

CONCLUSIONS

There are three possible MRI findings that can be used to determine the presence or absence of symptomatic extraforaminal disc herniation. Among these MRI findings, focal eccentricity of the disc was found to be the most reliable.

Percutaneous endoscopic lumbar discectomy: clinical and quality of life outcomes with a minimum 2 year follow-up

Background

Percutaneous endoscopic lumbar discectomy is a relatively new technique. Very few studies have reported the clinical outcome of percutaneous endoscopic discectomy in terms of quality of life and return to work.

Method

55 patients with percutaneous endoscopic lumbar discectomy done from 2002 to 2006 had their clinical outcomes reviewed in terms of the North American Spine Score (NASS), Medical Outcomes Study Short Form-36 scores (SF-36) and Pain Visual Analogue Scale (VAS) and return to work.

Results

The mean age was 35.6 years, the mean operative time was 55.8 minutes and the mean length of follow-up was 3.4 years. The mean hospital stay for endoscopic discectomy was 17.3 hours. There was significant reduction in the severity of back pain and lower limb symptoms (NASS and VAS, p < 0.05) at 6 months and 2 years. There was significant improvement in all aspects of the Quality of Life (SF-36, p < 0.05) scores except for general health at 6 months and 2 years postoperation. The recurrence rate was 5% (3 patients). 5% (3 patients) subsequently underwent lumbar fusion for persistent back pain. All patients returned to their previous occupation after surgery at a mean time of 24.3 days.

Conclusion

Percutaneous endoscopic lumbar discectomy is associated with improvement in back pain and lower limb symptoms postoperation which translates to improvement in quality of life. It has the advantage that it can be performed on a day case basis with short length of hospitalization and early return to work thus improving quality of life earlier.

Inter- and intra-observer reliability of MRI for lumbar lateral disc herniation

Background

The authors analyzed inter- and intra-observer agreement with respect to interpretation of simple magnetic resonance T1- and T2-weighted axial and sagittal images for the diagnosis of lumbar lateral disc herniation, including foraminal and extraforaminal disc herniations.

Methods

Forty-two patients in whom lumbar lateral disc herniation was suspected or confirmed by simple magnetic resonance imaging at one institute between May 2003 and December 2004 were included. The magnetic resonance images consisting of T1- and T2-weighted axial and sagittal images, and these were reviewed blindly and independently by three orthopaedic spine surgeons in a random manner. The images were interpreted as positive or negative for lateral disc herniation on 2 different occasions 3 months apart. Results were analyzed using Cohen's kappa statistic, and strengths of agreements were determined using the Landis and Koch criteria.

Results

The kappa values for inter-observer agreement averaged 0.234 (0.282, 0.111, and 0.308 respectively) on the first occasion, and 0.166 (0.249, 0.111, and 0.137 respectively) on the second occasion, with an overall mean value of 0.200. Thus, the strength of agreement was only slight-to-fair according to the Landis and Koch criteria. Kappa values for intra-observer agreement averaged 0.479 (0.488, 0.491, and 0.459 respectively), indicating moderate agreement.

Conclusions

The present study indicates that simple magnetic resonance imaging is not a reliable imaging modality for diagnosing lumbar lateral disc herniation. Another imaging study with improved diagnostic values should be developed to diagnose this pathologic finding.

Minimally invasive approach to extraforaminal disc herniations at the lumbosacral junction using an operating microscope: case series and review of the literature

Surgical access to extraforaminal lumbar disc herniations is complicated due to the unique anatomical constraints of the region. Minimizing complications during microdiscectomies at the level of L5–S1 in particular remains a challenge. The authors report on a small series of patients and provide a video presentation of a minimally invasive approach to L5–S1 extraforaminal lumbar disc herniations utilizing a tubular retractor with microscopic visualization.

[Minimally invasive transmuscular approach for the treatment of lumbar far lateral disc herniation]

BACKGROUND

The purpose of this study was to evaluate a minimally invasive surgical technique for the treatment of lumbar far lateral disc herniation. This technique combines the tubular retractor with the operative microscope.

OBJECTIVE AND METHODS

This retrospective study analyzed the files of 26 patients: 15 men and 11 women. The average age was 56 years (range, 19-83 years). The most commonly operated level was L3-L4 (46%), then L4-L5 (30.5%) and finally L2-L3 (15.5%). All patients were operated under general anesthesia. The intraoperative radioscopic location was absolutely necessary. A 12-15 mm paramedian incision was made on the side of the herniation (30 mm from the medial line). We then inserted the tubular muscular retraction system followed by the 14 mm diameter working channel. Guided by operating microscope, the articular isthmus was reamed to expose the root and the disc. The disc herniation was then removed after opening and removing the inter-transverse ligament.

RESULTS

The average duration of the surgery was 55 min. This operating time decreased as the surgeons gained experience. The radicular pain, estimated using the analogical visual scale, varied from seven before surgery to two during the postoperative period. All the patients were standing up the day after surgery. The average duration of the postoperative stay in the hospital was three days (range, 1-5 days). We noted no complications from the surgical procedure. The average duration of the follow-up was two years (range, 6-36 months).

CONCLUSION

This technique combines the advantages of endoscopic surgery (less muscular and osseous damage) and microscope-guided surgery (three-dimensional vision) and provided good functional results in this series.

Avaliação da relação entre parâmetros antropométricos (peso e altura) e a topografia da raiz de L4 no espaço intertransversário L4-L5 através do acesso paramediano à coluna vertebral- Um estudo anatômico em vinte e um cadáveres

As hérnias discais extremolaterais correspondem a 10% das hérnias discais sintomáticas, mais comumente localizadas nos níveis L3-L4 e L4-L5. Por muitos anos, a abordagem cirúrgica das hérnias lombares foraminais e extraforaminais foi feita através de via de acesso posterior mediana com hemilaminectomia e facetectomia total ou parcial. A abordagem cirúrgica dessa patologia pela via paramediana, entre os músculos multífido e longuíssimo (via de Wiltse), tem a vantagem de poupar o paciente de perdas ósseas e permitir uma visão mais oblíqua do neuro-foramen. Essa abordagem permite, com mínima mobilização da raiz de L4, acesso ao disco L4-L5 e eventuais herniações extra-foraminais do mesmo. Nosso objetivo é avaliar se há relação entre características antropométricas de um indivíduo e a localização da raiz de L4 no espaço intertransversário, acessado pela via de Wiltse, para com isso poder antecipar alguns riscos cirúrgicos. Foram realizadas dissecções em 21 cadáveres (42 lados) e obtidas as respectivas medidas de peso e altura além da distância entre a base do processo transverso de L5 e o ponto onde a raiz de L4 o cruza. A análise dos dados nos permite concluir que não há relação estatisticamente significativa entre as variáveis envolvidas.

The effect of removing the lateral part of the pars interarticularis on stress distribution at the neural arch in lumbar foraminal microdecompression at L3-L4 and L4-L5: anatomic and finite element investigations

STUDY DESIGN

The assessment of L3 and L4 pars interarticularis thickness and finite element analysis of stress distribution across L3 and L4 pars interarticularis.

OBJECTIVE

To quantify the morphology of the region of the L3 and L4 pars interarticularis and to assess the stress increase as a function of access size using the finite element lumbar spine model.

SUMMARY OF BACKGROUND DATA

Inadequate decompression and traction of the nerve structures are several causes of the unsatisfactory outcomes in patients after foraminal stenosis decompression and far lateral disc herniation removal by extraforaminal exposure. Enlarging the access of the foraminal exposure by the removal of the lateral aspect of the pars interarticularis may be able to diminish the inadequate decompression and traction of the nerve structures; however, it may lead to increase stress and fracture of the neural arch.

METHODS

We used 15 human cadaver L3 and L4 lumbar vertebrae for measuring the thickness of the pars interarticularis. The ventral and dorsal surfaces were subdivided into 4 equal parts, and the thickness of each part was measured using a digital caliper. An experimentally validated 3-dimensional nonlinear finite element model of the intact L3-S1 segment was used to simulate the lateral removal of one fourth and one half of the L3 and L4 pars interarticularis.

RESULTS

The mean thicknesses of the pars interarticularis showed a gradual increase toward the lateral edge. Finite element model analyses predicted stresses increased to 35% and 40% after removal of one half of the lateral part of the L3 and L4 pars interarticularis, respectively, and were much closer to the intact spine after removal of one fourth of the lateral part of the pars interarticularis.

CONCLUSION

The removal of one fourth of the lateral aspect of the pars interarticularis has minimal influence on the stresses in the remaining L3 and L4 neural arches. The lateral half of the pars has the largest thickness, and its removal leads to considerable stress increases.

Minimally invasive far lateral microendoscopic discectomy for extraforaminal disc herniation at the lumbosacral junction: cadaveric dissection and technical case report

BACKGROUND CONTEXT

Extraforaminal lumbar disc herniations (ELDHs) at the lumbosacral junction are an uncommon cause of L5 radiculopathy. The surgical anatomy of the extraforaminal space at L5-S1 is uniquely challenging for the various open surgical approaches that have been described for ELDHs in general. Reports specifically describing minimally invasive surgical approaches to lumbosacral ELDHs are lacking.

PURPOSE

To report the novel use of a far lateral microendoscopic (FLMED) approach to lumbosacral ELDH. To better define the unique anatomical features of extraforaminal approaches to the lumbosacral junction as they apply to minimal access techniques.

STUDY DESIGN/SETTING

A cadaveric investigation and clinical case were performed at a single institution. A thorough review of the literature was conducted.

PATIENT SAMPLE

A single patient with an extraforaminal disc herniation at the lumbosacral junction underwent evaluation and surgery.

OUTCOME MEASURES

The patient's self-reported pain levels were documented. Physiologic outcome was judged on pre- and postoperative motor and sensory examinations. Functional capacity was assessed by work status and ability to perform activities of daily living.

METHODS

FLMED was performed in two fresh human cadavers at the lumbosacral junction. Qualitative assessments of the surgical anatomy were made, and intraoperative fluoroscopy and endoscopic photographs were obtained to document the findings. A patient with refractory pain and sensorimotor deficits from compression of the L5 nerve root by an ELDH underwent FLMED. The literature was carefully reviewed for the epidemiology of ELDHs at the lumbosacral junction and the surgical techniques used to treat them.

RESULTS

The posterolateral surgical corridor to the lumbosacral disc was consistently constrained by the sacral ala and to a lesser extent the lateral facet and L5 transverse process. Resection of the superior ala exposed the exiting nerve root and provided ample access to the disc. In the clinical case, the patient enjoyed immediate pain relief, was discharged in 3 hours, and returned to full work and social activities. Follow-up neurological examination revealed no sensory or motor deficit.

CONCLUSIONS

FLMED offers a safe and efficacious approach to ELDHs at the lumbosacral junction by combining satisfactory visualization for adequate resection of the sacral ala with the benefits of reduced tissue injury and faster recovery times that accompany minimally invasive techniques.

A minimally invasive transmuscular approach to far-lateral L5-S1 level disc herniations: a prospective study

BACKGROUND

Among all lumbar disc herniations, L5-S1 far-lateral disc herniations are rare entities. Besides, surgical approach may be difficult because of the very narrow passage at this level. For these 2 reasons, most spine surgeons are not experienced in herniations at this level. According to new microanatomic studies, previous lateral approaches at this level often do not allow access to the neuroforamen without partial or total destruction of the L5-S1 facet joint. To preserve the facet joint, an approach was developed.

PURPOSE

To assess the efficacy of a surgical technique that is a minimally invasive intermuscular approach (MIIMA) for decompression of L5-S1 far-lateral level disc herniation (FLLDH).

STUDY DESIGN

We present a prospective clinical study analysis of 14 patients with L5-S1 far-lateral disc herniations in a period between 2000 and 2004, treated with microsurgical technique.

METHODS

An imaging study revealed consistency with the patient's clinical presentation. In our department, a total of 580 patients underwent discectomy between 2000 and 2004 for lumbar disc herniation.

RESULT

Twenty-eight patients had foraminal or extraforaminal herniations (4.8%). Fourteen patients had FLLDH at the L4-L5 level (2.4%), whereas the other 14 were cases of FLLDH at the L5-S1 level (2.4%). One patient had FLLDH at both L5-S1 and L4-L5 levels (7.1%). The mean age of patients was 53.6 years, and the male:female ratio was approximately 5:9. All patients failed to recover after at least 6 weeks of conservative therapy. The mean duration of symptoms until the time of surgery was 7.2 months. Using this MIIMA technique, the authors removed the herniated discs compressing the (L5) nerve roots. Clinical outcome was measured using the visual analog scale. Every patient was discharged within 24 hours. Satisfactory (excellent or good) results were demonstrated in 13 patients (92.9%), because, except for 1 (7.1) permanent dysesthesia case, 4 cases (21.3%) were temporary dysesthesia. Postoperatively all patients reported excellent relief of their sciatic pains, and there were no technique-associated complications. No recurrence was observed during the follow-up period ranging from 10 to 60 months (mean, 29 mo). This is one of the major complications of any approach to a far-lateral disc.

CONCLUSIONS

The authors describe a MIIMA for excising herniated discs that is applicable to all types of far-lateral lumbar herniations. Postoperative dysesthesia is the most important complication and may persist as it did in our cases. Consequently, manipulation of the ganglion should be avoided at all costs, if possible. The MIIMA procedure provides a simple alternative for treating lumbar foraminal or lateral exit zone herniated discs in selected cases. This approach is effective, allowing the preservation of the L5-S1 facet joint, saving the facet joint, preventing postoperative instability, and offering a direct view of the L5-S1 neuroforamen.

Transforaminal Percutaneous Endoscopic Discectomy in the Treatment of Foraminal and Extraforaminal Lumbar Disc Herniations

The objective of this study is to evaluate the efficacy of the endoscopic technique, as applied to patients with foraminal and extraforaminal disc herniations, and to report the outcome and complications. A retrospective analysis was performed of 35 consecutive cases of foraminal and extraforaminal lumbar disc herniation managed by posterolateral endoscopic discectomy. Pain was measured by means of the Visual Analog Score. Patient satisfaction was evaluated by the Macnab outcome criteria. The median follow-up period was 18 months (range 10 to 35 months). The mean Visual Analog Score improved from 8.6 before the surgery to 3.2 after the surgery. Overall, excellent or good outcomes were obtained in 30 (85.7%) of the 35 patients at the last follow-up examination, with both these outcomes showing statistically significant improvement (P<0.01). There were no complications related to the surgery, nor was any spinal instability detected. Three patients (8.6%) experienced persistent radiculopathy and subsequently underwent open microdiscectomy at the same level. We concluded that transforaminal percutaneous endoscopic discectomy is safe and efficacious in the treatment of foraminal or extraforaminal disc herniations. However, proper patient selection is paramount to ensure a satisfactory outcome after decompression of foraminal and extraforaminal disc herniations.

Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression

STUDY DESIGN

A retrospective study of consecutive patients who underwent microdecompression for far lateral disc or foraminal stenosis.

OBJECTIVES

To evaluate the risk factors for unsatisfactory outcome.

SUMMARY OF BACKGROUND DATA

There has been no detailed analysis of postoperative radicular pain, although it is not infrequent following foraminal and far lateral microdecompression.

METHODS

A total of 184 patients, who were followed up for more than 2 years, were reviewed. Microdecompression was performed through lateral intermuscular approach. In cases of double herniation (combination of intracanalicular disc at the same level), additional intracanalicular decompression was simultaneously performed. The unsatisfactory outcomes included persistent or recurrent leg pain, based on the Japanese Orthopedic Association leg pain score, and revision surgery at the same level. The potential risk factors, including gender, age, symptom period, preoperative radiologic and intraoperative findings, were determined.

RESULTS

The average follow-up period was 38.4 months, with a maximum 70 months. Forty of the 184 patients (21.7%) had persistent or recurrent leg pain, with nine requiring revision surgeries. The statistically significant risk factor for unfavorable outcomes was double herniation, with odds ratio of 2.89 (P = 0.004).

CONCLUSION

Facet preserving microdecompression is an effective method for foraminal and far lateral root compression. However, in cases of double herniation, total facetectomy is preferable.

[Transsacral approach to lumbosacral extraforaminal disc herniations]

INTRODUCTION

The lateral approach is classically used for surgical treatment of extraforminal disc herniations (EDH). However, its use at the level of the L5-S1 space can require more or less extensive resection of the facet joint. This study reports our experience in the treatment of L5-S1 EDH using the transsacral approach described by Muller and Reulen in 1998.

MATERIAL AND METHODS

From February 2002 to October 2004, 12 patients presenting EDH at the L5-S1 level underwent treatment using the transsacral approach. There were 8 men and 4 women. Mean age was 55 years (range: 36 to 75 years). All patients presented lumbalgia and L5radiculalgia. Only one patient had dysesthesia. Five patients presented motor deficits and 3 presented sensory deficits. Surgical treatment was proposed after failure of medical treatment and two L5 corticoids infiltrations.

RESULTS

All patients were re-examined two months after the procedure. Mean follow-up was 15 months. Complete resolution of radiculalgia with no paresthesia was achieved in all patients. Patients presenting preoperative motor deficit recovered fully after treatment. All patients resumed normal activity.

CONCLUSION

The transsacral approach is a valid alternative to the lateral approach for treatment of L5-S1 EDH. The amount of operative exposure achieved using this technique is sufficient to avoid joint injury that can result in chronic postoperative lumbalgia. Another advantage is that excision of the protruding disc fragment can be achieved without mobilization of the nerve root or dorsal root ganglion, thus avoiding postoperative dysesthesia.

Interlaminar approach for excision of lateral lumbar disc herniation: technical note

STUDY DESIGN

Technical note.

OBJECTIVE

To show that approaching the lateral lumbar disc from the contralateral interlaminar space offers a wider exposure with reduced facet removal.

SUMMARY OF BACKGROUND DATA

The interlaminar approach is a well-established approach for the removal of lateral lumbar disc herniation (LLDH). However, access to the lateral disc space via this approach may be difficult and requires generous facet joint removal.

METHODS

A 41-year-old woman presented with a 2-year history of low back pain and severe left leg pain. Computerized tomography of the lumbar spine revealed a left-sided intraforaminal lateral disc protrusion at L4/5 level.

RESULTS

The patient underwent a left L4/5 discectomy and removal of the lateral disc via the interlaminar approach from the contralateral (right) side with excellent postoperative result.

CONCLUSIONS

The authors present a modification of the interlaminar microsurgical approach for excision of an intraforaminal lateral disc herniation in which the herniated disc is approached from the contralateral interlaminar space through a midline incision. The facet joint removal is less, and the exposure is superior to the traditional interlaminar approach.

Mapeamento do trajeto extraforaminal da raiz L4 no espaço intertransversário L4-L5 através do acesso paramediano à coluna vertebral

As hérnias discais extremolaterais correspondem a 10% das hérnias discais sintomáticas, mais comumente localizadas nos níveis L3-L4 e L4-L5. Por muitos anos, a abordagem cirúrgica das hérnias lombares foraminais e extraforaminais foi feita através de via de acesso posterior mediana com hemilaminectomia e facetectomia total ou parcial. Inúmeras foram as variações propostas para essa técnica a fim de se evitar a facetectomia e suas repercussões biomecânicas, que ocasionavam com certa freqüência o surgimento de dor lombar baixa devido à instabilidade vertebral criada. A abordagem cirúrgica dessa patologia pela via paramediana, entre os músculos multífido e longuíssimo (via de Wiltse), tem a vantagem de poupar o paciente de perdas ósseas e permitir uma visão mais oblíqua do neuro-foramen. Essa abordagem permite, com mínima mobilização da raiz de L4, acesso ao disco L4-L5 e eventuais herniações extra-foraminais do mesmo. Nosso objetivo é apresentar um estudo do trajeto extra-foraminal da raiz de L4 no espaço intertransversário L4-L5. Para isso, foram realizadas dissecções em 10 cadáveres (20 lados) e obtidas as medidas baseadas em 6 parâmetros anatômicos. A análise dos dados nos permite concluir que as hérnias discais extremo-laterais no nível L4-L5 podem ser acessadas com relativa segurança através da via paramediana.

Lateral transmuscular or combined interlaminar/paraisthmic approach to lateral lumbar disc herniation? A comparative clinical series of 48 patients

BACKGROUND

The optimum operative technique for lateral lumbar disc herniations (LLDH) remains unclear, and both interlaminar and extraspinal approaches are used.

OBJECTIVE

To compare outcome after LLDH removal either by a lateral transmuscular approach (LTM) or by a combined interlaminar and paraisthmic approach (CIP).

METHODS

28 patients underwent surgery using CIP and 20 using LTM. All patients were operated on by the same neurosurgeon. The clinical presentation of the two groups was comparable. Overall outcome was assessed after a mean follow up period of between 19 and 37 months using the Ebeling classification. In addition, the effect of surgery on radicular pain, low back pain, and sensory and motor deficits was defined.

RESULTS

Excellent to good results were achieved in 95% of the LTM group and 57% of the CIP group. The outcome was satisfactory to poor in 5% of the LTM and 43% of the CIP group (p<0.004). The percentage of sensorimotor deficit and of radicular pain improvement was higher in the LTM group. New low back pain was found exclusively in the CIP group (21%). The complication rate was 5% in the LTM group and 11% in the CIP group.

CONCLUSIONS

The LTM approach achieves a better overall outcome and improvement in radiculopathy. The complication rate is lower with the transmuscular route and the risk of new low back pain is minimised. These results are likely to be attributable at least in part to the lesser invasiveness of the LTM approach.