腰腿痛作为一类最常见的腰椎疾患,常出现在生活中!本视频以椎间盘突出症为典型,介绍腰椎退变性疾病的病因、诱因、诊断和治疗的选择。
Percutaneous endoscopic lumbar decompression for lumbar lateral spinal canal stenosis: classification of lateral region of lumbar spinal canal and surgical approachesYu Wang, MD1, Qingyu Dou, MD2, Jin Yang, MD1, Lifeng Zhang, MD1, Yuqing Yan, MM1, Zhiyu Peng, MD1, Chuan Guo, MM1, Qingquan Kong, MD1Yu Wang and Qingyu Dou are co-first authors.From the1Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China;2Department of Cardiology, West China Hospital of Sichuan University, Chengdu, ChinaAddress correspondence and reprint requests to Qingquan Kong, MD, Department of Orthopedics Surgery, West China Hospital, Sichuan University,No. 37, Guoxue Lane, Wainan Street, Wuhou District,Chengdu, Sichuan 610041, China;Tel: 86-28-85422570;Fax: 86-28-85423438;E-mail: kqqspine@126.com.Keywords:lumbar spinal stenosis; lateral lumbar spinal canal; functional classification; percutaneous endoscopic lumbar decompression (PELD)AbbreviationsLumbar Spinal Stenosis (LSS)Percutaneous Endoscopic Lumbar Decompression (PELD)Lateral Lumbar Spinal Canal (LLSC)Visual Analog Scale (VAS)Superior Articular Process (SAP)Percutaneous Endoscopic Transforaminal Decompression (PETD)Percutaneous Endoscopic Interlaminar Decompression (PEID)Posterior Apophyseal Ring Separation (PARS)Ossification of Posterior Longitudinal Ligament (OPLL)AbstractPurposeThe purpose of this study was to provide a new classification of the lateral region of the lumbar canal (LLSC) and evaluate the clinical outcome of surgical treatment of LLSC stenosis guided by the classification.MethodsWe developed a new functional classification of the LLSC by dividing the region into five zones. Thirty random lumbar imaging studies from single-level LLSC stenosis patients in our department from January 2015 to June 2015 were evaluated by 3 examiners to validate its reliability. Subsequently, a prospective clinical outcome study of 76 single-level LLSC stenosis patients from July 2015 to July 2016 with 2-year follow-up was undertaken. All patients received either percutaneous endoscopic transforaminal decompression (PETD) with foraminoplasty or percutaneous endoscopic interlaminar decompression (PEID), according to the guidance of the classification. Clinical outcomes were evaluated by Macnab criteria, and pre- and postoperative leg pain were evaluated using the visual analog scale (VAS).ResultsWe observed a 93.3% agreement among examiners. The mean follow-up duration was 15.6 months (range 3-24). We obtained 93.4% good and excellent outcomes at the last follow-up.The mean preoperative VAS score was 5.72±1.18 (range 4-9), which decreased to 1.26±0.81 (range 0-3) at the third month postoperatively and to 0.78±0.62 (range 0-1) by the last follow-up visit.Dural tears appeared in 2 patients, and migrated bone moved into the spinal canal after the operation in 1 patient.ConclusionsThe new classification of LLSC can provide objective criteria for full-endoscopic surgery that may lead to better clinical outcomes.IntroductionLumbar spinal stenosis (LSS) anatomically involves the central canal, lateral recess, foramina or any combination of these locations. However, when we talk about the lateral region of the spinal canal, authors put forward many different terms, such as radicular canal, lateral recess zone or nerve root canal1-3.The term “radicular canal” was the first term introduced for the lateral region of the spinal canal1, 3, 4. The exact anatomical location and borders were highly dependent on the presence of spinal nerve roots whose point of emergence vary widely in different lumbar segments. Moreover, it presents several difficulties in determining the exact point of emergence of each nerve root using routine radiological examination. In 1955 and 1972, Schlesinger and Epstein, respectively, reported some cases and described the clinical and radiographic findings of facet syndrome5, 6. Since then, several authors recognized and described the term “lateral recess”2, 6, 7. One of its advantages is the unchangeable border which can be confirmed easily by anatomic landmarks or general radiological examination. However, controversy on its boundaries and exact definition still exists1, 3-5, 7-9. Accordingly, there is still no acknowledged term describing the lateral region in the lumbar spinal canal.Owing to the remarkable evolution ofpercutaneous endoscopic lumbar decompression(PELD), the paradigm of spinal endoscopy is shifting from treatment of soft disc herniation to those with lumbar spinal stenosis. Satisfactory results of PELD for lateral lumbar stenosis are reported at 82-92%10. However, there is still no effective classification of the lateral spinal region, which is important to guide choice of surgical procedures.After carefully analyzing the characteristics of different regions in the lateral region of the spinal canal, we recommend the term lateral lumbar spinal canal (LLSC) and divide the region into five zones based on different anatomical features. From July 2015 to July 2016, 76 patients with single-level LLSC stenosis were treated with PELD and were followed up for as long as two years. We aimed to (1) investigate the underlying concept, functional anatomy and provide the new functional classification of the LLSC by classifying it into five zones and (2) assess clinical outcomes of the different operation methods for each zone, guided by this classification.MethodsStudy designInitially, we collected all preoperative imaging data, including MRI and CT images, in LLSC stenosis patients who presented to our department and underwent PELD from January 2015 to June 2015. A retrospective evaluation of all images was used to develop the new functional classification. To test its reliability, a blind review of 30 random lumbar imaging studies from this series was performed independently by three different examiners using the new functional classification.In the second step, a prospective cohort study was undertaken.Among more than 500 cases undergoing PELD by a single surgeon (KQQ) from July 2015 to July 2016, 76 LLSC stenosis patients with informed consent and complete collection of clinical data wereincluded, aiming to validate the classification scheme. We assessed the overall surgical outcomes from this second series.Patient populationThe mean age of the 76 patients was 51.9 years (range 14-90 years). Fifty-five were male, and 21 were female. All patients were diagnosed with single-level LLSC stenosis with the complaint of leg pain with or without back pain. Preoperative MRI and CT images were obtained in all patients. Patients with simple disc herniation (without other stenotic conditions) were excluded. Stenosis was diagnosed when the nerve root was shown to be trapped in any zone by preoperative MRI and CT with clinical symptoms or signs attributable to this root. Preoperative blocking of the nerve root could be applied in some intractable cases.Clinical follow-ups were made at the end of three months, and at two years. Clinical outcomes were assessed by an independent surgeon (WY) using the Macnab criteria11. Excellent and good outcomes were recorded in the last follow-up and rated as clinical success. The intensity of leg pain was measured using a visual analog scale (VAS), ranging from no pain (point 0) to the worst pain imaginable (point 10).The new functional classificationThe new functional classification takes both the pathway of nerve root and biomechanical/pathological characteristics of each zone into account. We defined the medial border of the LLSC as the midline of the medial pedicular line and spinous process line and divided the space into five zones. Detailed boundaries of each zone are summarized in Table 1, and Figures 1 and 2.Table 1 Detail boundary of each zoneSuperior BoundInferior BoundMedial BorderLateral BorderVentral AdjacentDorsal AdjacentZone 1Inferior edge of the above vertebral bodySuperior edge of the vertebral bodyThe midline of medial pedicular line and spinous process line(open to central canal)The medial pedicular line(open to intervertebral foramen)Posterolateral surface of the discSuperior articular process (SAP)Zone 2Superior edge of the vertebral bodyHorizontal mid pedicular lineSame as aboveSame as above(adjoin to medial surface of pedicles)Posterior surface of the vertebral bodyFacet joint, lateral part of the lamina and attached ligamentum flavumZone 3Horizontal mid pedicular lineHorizontal inferior pedicular lineSame as aboveSame as aboveSame as aboveAnterior surface of laminaZone 4Horizontal inferior pedicular lineInferior edge of the vertebral bodySame as aboveSame as above(open to intervertebral foramen)Same as abovePars interarticularis/laminaZone 5Inferior margin of the pedicleSuperior margin of the adjacent pedicleMedial pedicular line (open to central canal)Lateral pedicular lineThe disc and posterior margin of the two adjacent vertebral bodiesLateral aspect of the facet jointRetrodiscalSpace (zone 1)The retrodiscal space corresponds to the entrance zone described by Lee C.K2, which is represented as the most cephalad part of the lateral canal. The space parallels the disc height, which is constrained by the disc and the superior articular process (SAP), joint capsule and ligamentum flavum. Parasagittal and axial MRI T2-weighted images were indispensable when diagnosing stenosis because the main compressive factors were the presence of a herniated disc and hypertrophied ligamentum flavum. Intervertebral discs presented in axial MRI or CT images was the symbol of this zone.Upper Bony Lateral Recess (zone 2)Based on different anatomical features, we creatively divided the whole bony lateral recess into two parts. The upper part equaled the space in front of the facet joint, lateral part of the lamina and attached ligamentum flavum. Therefore, it is a narrow space defined by bony structures, the vertebral body anteriorly and the facet joint posteriorly. The bony structures determining the bone window of axial CT scans was necessary, which presents a slender region formed by the vertebral body and the facet joint. Therefore, we used the facet joint as the symbol of this zone when we identified the stenotic condition by radiological images.Lower Bony Lateral Recess (zone 3)We defined the horizontal midline of the pedicle, which equals the inferior border of the SAP, as the demarcation between zones 2 and 3. Differentiating from zone 2, zone 3 was surrounded by the vertebral body, pedicle and lamina. This three-edge osseous ring made the space invariable in different lumbar positions. Stenosis in this zone must be diagnosed from a bone window of axial CT scans showing the bony deltoid region. The posterior wall, SAP and lamina were decisive when identifying stenosis in zone 2 or 3.Inside Part of Intervertebral Foramen (zone 4)This region located on the inside of intervertebral foramen has rarely been mentioned in works of literature. Only a fraction of the nerve roots run through this zone. It can also be demonstrated by bony window CT axial scans. The anterior and posterior wall are same as zone 3. Thus, the non-existence of the outer wall was the indication of zone 4.Intervertebral Foramen (zone 5)The existing definition given by Lee2is then introduced. The scope of the intervertebral foramen has been widely acknowledged. Both MRI and CT are indispensable because compression can be by either the anterior LDH or other bony structures.Surgical techniquesAll patients were treated by PELD. Percutaneous endoscopic transforaminal decompression (PETD) with foraminoplasty was used in patients the following conditions: (1) stenosis in zone 5 or mixed zones containing zone 5 or (2) stenosis limited to zone 1, zone 2 or zone 1+2, except for that in L5/S1.Percutaneous endoscopic interlaminar decompression (PEID)was used in patients with (1) stenosis in zone 3 or 4 or mixed zones containing either of them or (2) L5/S1 stenosis,except in zone 5.PETD with foraminoplastyAll PETD procedures employed by the author were essentially a classic Thessys technique popularized by Hoogland et al.12or a variation of it. The procedures were performed under local anesthesia in the prone position on aradiolucenttable using C-arm fluoroscopy.An 18-G needle was inserted into the safe zone of Kambin’s triangle. Techniques to define the skin entry point and surgical trajectory have been described previously13. After infiltrating 15–20 ml of 0.5% lidocaine in the intervertebral foramen, the needle was replaced with a 1-mm-diameter guide wire. A blunt tapered cannulated obturator was passed over the guide wire under fluoroscopic control. Sequential protective cannulas were introduced over the obturator until the final protective cannula was placed in proper position.A 10-mm-diameter trephine was used to perform foraminoplasty, which was facilitated by changing the specific location of the needle tip and trajectory of trephine to aim for the different compressive pathology which is described in detail in Table 2. After that, the protective cannula was replaced with an 8-mm working cannula. Thenhypertrophied ligamentum flavum, facet joints and anterior herniated discwere endoscopically resected to achieve the decompression. Epidural bleeding was controlled with a radiofrequency probe under saline irrigation.Table 2 Differences of foraminoplasty methods for zonesLocation of needle tipThe inclination of the trephineRemoved structuresAnteroposterior (AP) viewLateral viewZone 1Medial pedicular linePosterior rim of the upper endplateParallel to the upper endplateSuperior-ventral portion of SAP and part of inferior articular process (IAP)Zone 2Inferior-lateral border of SAPInferior-ventral of SAPDownwards making an angle of 0-25 with the upper endplate in AP review(depended on the exact location of stenosis)Inferior-ventral portion of SAP, the upper part of pedicle (in some cases)Zone 1+2Same as zone 1Same as zone 1Step 1: from the tip of SAP to the posterior rim of the upper endplate of distal vertebral (target to retrodiscal space)Step 2: the tip of SAP to mid-point of middle pedicular line on the posterior surface (target to upper bony lateral recess)(Figure 3)Ventral portion of SAP, a part of IAP, lamina, the upper part of pedicle (in some cases)Zone 5Same as zone 1Same as zone 1Same as zone 1The tip of SAPPEIDPEID was performed using a technique described previously14. The operation was performed after induction of general anesthesia.A dilator was inserted bluntly to the lateral edge of the interlaminar window and an operating sheath with a beveled opening was directed toward the ligamentum flavum.Thereafter, the procedure was performed under visual control and constant irrigation. The decompression began by means of resection of bones and flavum segments using burs and punches.Burs and forcepswere used to remove the compression in zone 3 or 4, such as posterior apophyseal ring separation (PARS), ossification of the posterior longitudinal ligament (OPLL), and hypertrophied ligamentum flavum/ SAP and herniated disc in zone 1 and 2.ResultsReliabilityThe three examiners classified lateral lumbar spinal canal stenosis with a 93.3% agreement. There were three differing zones reported among the three examiners. The first one wasreported as zone 1+2+3 by two of the examiners and as zone 1+2 by the third.The second was reported as zone 1+2+5 by two and as zone 1+2 by the third. The last was reported as zone 1+5, zone 5, and zone 1 by three examiners. Therefore, there were 83 concordant observations out of 90 possible pairs.Clinical ResultsSeventy-six patients presented with a total of 131 different zones. Levels of stenosis were L3/4 in two patients (2.6%), L4/5 in forty (52.6%), and L5/S1 in thirty-four (44.7%). Stenosis of 62 patients (81.6%) occurred limited to zone 1, 2 or 1+2. Five patients (6.6%) had involvement in zone 3 (in zone 1+2+3), three of them were caused by isthmic spondylolisthesis, and the other two were due to a massive PARS. The only patient (1.3%) had involvement in zone 4, which was caused by a calcified sequestered disc. Intervertebral foramen stenosis (zone 5) occurred in eight patients (10.5%), combined with zone 1 or 2 simultaneously (Figure 4). Thirty-seven patients received PEID (five were stenosis in zone 3, one in zone 4 and 31 in zone 1/2/1+2 in L5/S1) and 39 received PETD (eight were stenosis in zone 5, 31 were zone 1/2/1+2 in L3/4 or L4/5).The mean follow-up period was 15.6months (range 3-24). According to the modified Macnab criteria, satisfactory (excellent or good) results were distributed as shown in Table 3. The difference among groups was not statistically significant.Table 3 Clinical outcome according to the Macnab criteriaZonesNumber of patient (% in each zone)ExcellentGoodFairPoortotalsatisfactoryZone 19 (40.9)12 (54.5)0 (0.0)1 (4.5)2295.4%Zone 22 (2.9)4 (5.7)1 (14.3)0 (0.0)785.7%Zone 1+212 (36.3)19 (57.6)1 (3.0)1 (3.0)3393.9%Zone 1+2+3/ Zone 41 (16.7)5 (83.3)0 (0.0)0 (0.0)6100%Zone 1+5/ Zone 1+2+53 (37.5)4 (50.0)1 (12.5)0 (0.0)887.5%Total27(35.5)44(57.9)3(3.9)2(2.6)7693.4%The mean preoperative VAS score was 5.72±1.18 (range 4-9), which decreased to 1.26±0.81 (range 0-3) at the third month postoperatively and to 0.78±0.62 (range 0-1) by the last follow-up visit. All operations were performed successfully without any nerve root injury or hematoma formation during the procedure. Dural tears appeared in two patients. After conservative treatment including complete bed rest and fluid infusion, both were cured without residual symptoms. In addition, there was one case of migrated bone that moved into the spinal canal after foraminoplasty, which caused severe symptoms. We performed a second exploration and removed the free bone fragment after 2 months, achieving complete symptomatic relief. The complication rate was thus 3.9% (3/76). In addition, we found postoperative low back pain in 5 patients, which was relieved after conservative treatment. No other surgery-related complications occurred.DiscussionThe term “lateral lumbar spinal canal” was first introduced by Lee C.K2in 1988, and indicated the division of the region into entrance, mid and exit zones. This classification seemingly avoided distinguishing different starting-points of nerve roots, but it was still based on the path of nerve roots. Therefore, it was more suitable to be called the “radicular canal”. However, we still decided to adopt the term and try to give it a new, precise definition by dividing the region into five zones.We defined the LLSC as the narrow space in the lateral spinal canal that contains the full pathway of the nerve root from the point of leaving the dura sac to exit at the intervertebral foramen.The primary advantages of the redefined LLSC is a stable and sensible system because it does not rely on the path of nerve roots and corresponds with functional anatomical features. Moreover, we can easily recognize it by specific anatomic landmarks or general imaging examination, attributed to the precise boundaries we defined. In this study, the functional five-zone classification has been shown to be a viable method of assessment that has been coupled to our normal selection criteria for PELD at our institution. This classification can be a yardstick for preoperative evaluation and in determining the proper technique, which seems easy to reproduce with consistency by different examiners. Moreover, a comprehensive account is given on each surgical procedure for each zone.In this study, we summarized all patients into three groups (involving zone 1/2/1+2, zone 3/4 and zone 5) and analyzed each clinical outcome because pathogenic factors and surgical method (approach) were similar in each group. Of the observed patients, 81.6% were in zone 1 and/or 2, which suggested these are the most common regions for degeneration to occur. Intervertebral discs protruding anteriorly and hypertrophied facet joints/ligamentum flavum/ joint capsules posteriorly are the most common degenerative factors because spinal stress is concentrated on them. However, the difference is that the space in zone 1, surrounded by soft tissue, is variable among positions which determined that some indirect decompression technique may work. By contrast, in zone 2, the space is constant because it is formed by tricortical bony structures. Therefore, direct and complete decompression is indispensable. Many researchers reported using the PELD technique for treatment of stenosis in these regions and got favorable outcomes13-18. We selected PETD with improved foraminoplasty and achieved a highersatisfactory rate(93.5%) than previous studies. For patients with stenosis at L5/S1, we selected PEID because of the barrier of the iliac crest. We attribute it to the advantages of our creative accurate decompression technique realized by targeted decompression. In particular, we applied the innovative two-step foraminoplasty for zone 1+2 patients (Figure 3). First, targeting the retrodiscal space, the superior-ventral part of the SAP was removed. In addition, then, secondary foraminoplasty resulted in the medial-ventral part of the SAP being resected. This combined procedure can preserve normal facet joint structures as much as possible, such as the articular surface. At the same time, we obtained complete decompression.The low incidence (7.9%) of stenosis occurring in zones 3 and 4 can be explained by their special anatomical and biomechanical features. Both zones are comprised of bony structures: the vertebral body ventrally and laminar dorsally. Consequently, bony window CT scans are crucial in diagnosing stenosis here. In zone 3, the lateral wall is the pedicle. The space in the two zones is still not deformable, compared to positions in zone 2; however, the involved structures do not bear stress from lumbar activities, which contribute to infrequent degenerative changes in these regions. Thus, occupying ossification and isthmic spondylolisthesis are their main etiological factors. When the stenosis appears in these zones, PEID was recommended because it is difficult for PETD to reach the deep regions. Large occupying ossification (PARS or calcified sequestered disc) and compression caused by a fractured isthmus can be easily removed by burs and forceps via PEID. Six patients undergoing this procedure achieved 100% satisfactory rate without any complications.In total, eight patients (10.5%) experienced involvement in zone 5: four were zone 1+5, caused by a large herniated intervertebral disc, and the others, marked as zone 1+2+5, were caused by hypertrophy of facet joint/ligamentum flavum. As illustrated, this is an important area of compression because of impingement of SAP/disc or in a spondylolisthesis. The conventional surgical treatment is open paraspinal foraminotomy or total facetectomy combined with fusion surgery19{Jenis, 2000 #2671}. Knight et al. were the first to describe the technique of foraminoplasty for foraminal stenosis in selected cases; unfortunately, only 60% of patients obtained good or excellent outcomes20. Currently, PETD has become the most widely used surgical method for treating foraminal stenosis, even at L5/S1. In our study, we achieved a high rate of satisfactory results (87.5%), slightly higher than in other reports1320. As an aside,manipulation of the dorsal root ganglion (DRG) should be minimized to avoid postoperative symptoms such as pain and numbness.Although many people reported similar results with full-endoscopic surgery for lateral recess and foraminal stenosis, they did not employ radiologic classification as a surgical guideline or provide a detailed technical description for decompression10, 13, 14, 17, 18, 21-25. Kai-Uwerformed13performed similar procedures to ours in bony foraminal stenosis patients and achieved a 71.9% satisfactory rate. Kambin and Bingtao reported that the excellent and good rate was 82% and 73.4%, respectively, using intervertebral foramen approach23, 24. Zhenzhou Li reported a satisfactory rate of 90.5% (77/85) when they treated lateral recess stenosis with percutaneous lumbar foraminoplasty18. Rutten treated 81 lateral recess stenosis patients via full-endoscopic interlaminar approach and obtained 92% subjective satisfaction14. Zeinab performed PEID in lateral recess stenosis patients and 70% had good results17. In this study, we safely performed PELD in treating LLSC stenosis patients and achieved overall excellent and good results of 93.4%, which was higher than in previous studies. We attribute this to determining the accurate location preoperatively and precise decompression based on the treatment guideline of the functional classification and our targeted decompression technique. In addition, the careful selection of surgical indications and mature surgical skills are of great importance.We believe PELD can solve most cases of LLSC stenosis. However, we recommend open surgery if there is a possibility of incomplete removal of compressive factors, as in patients with severely hypertrophied facet joints, large calcified sequestered discs, or combined with central canal stenosis. Severe foraminal stenosis or spondylolisthesis are contraindications to PELD because they make it difficult to achieve proper epidural access. In our series of 76 cases, 3 complications (3.9%) occurred, including two dural tears and one instance of residual free bony fragments. The complication rate was significantly lower than previous studies14, 18, 24, 25,which was also attributed to the careful selection of surgical indications directed by the treatment guideline.We believe this low rate of complications is not unexpected and will probably decrease with further experience with this technique.ConclusionsThe new functional classification of LLSC appears useful to better qualify records, to standardize radiologic description, and to assist in patient surgical selection.Perhaps most importantly, as part of the surgical selection process, it may be useful in helpingprovide a more consistent approach to the full-endoscopic treatment of LLSC stenosis and may yield a higher incidence of excellent surgical outcomes for patients in the future.AcknowledgmentsWe thank the staff and patients for their contributions and participation in this study.Conflict of interest statementThe authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.Reference:1.Crock HV. Normal and pathological anatomy of the lumbar spinal nerve root canals. J Bone Joint Surg Br. 1981;63B(4):487-90.2.Lee CK, Rauschning W, Glenn W. Lateral lumbar spinal canal stenosis: classification, pathologic anatomy and surgical decompression. Spine (Phila Pa 1976). 1988;13(3):313-20.3.Lassale B, Morvan G, Gottin M. Anatomy and radiological anatomy of the lumbar radicular canals. Anat Clin. 1984;6(3):195-201.4.Vital JM, Lavignolle B, Grenier N, Rouais F, Malgat R, Senegas J. Anatomy of the lumbar radicular canal. Anat Clin. 1983;5(3):141-51.5.Epstein JA, Epstein BS, Rosenthal AD, Carras R, Lavine LS. Sciatica caused by nerve root entrapment in the lateral recess: the superior facet syndrome. J Neurosurg. 1972;36(5):584-9.6.Schlesinger PT. Incarceration of the first sacral nerve in a lateral bony recess of the spinal canal as a cause of sciatica. J Bone Joint Surg Am. 1955;37-A(1):115-24.7.Ciric I, Mikhael MA, Tarkington JA, Vick NA. The lateral recess syndrome. 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Medical Science Monitor. 2016;22:4604-11.17.Birjandian Z, Emerson S, Telfeian AE, Hofstetter CP. Interlaminar endoscopic lateral recess decompression-surgical technique and early clinical results. J Spine Surg. 2017;3(2):123-32.18.Li ZZ, Hou SX, Shang WL, Cao Z, Zhao HL. Percutaneous lumbar foraminoplasty and percutaneous endoscopic lumbar decompression for lateral recess stenosis through transforaminal approach: Technique notes and 2 years follow-up. Clin Neurol Neurosurg. 2016;143:90-4.19.Jenis LG, An HS. Spine update. Lumbar foraminal stenosis. Spine (Phila Pa 1976). 2000;25(3):389-94.20.Knight MT, Goswami A, Patko JT, Buxton N. Endoscopic foraminoplasty: a prospective study on 250 consecutive patients with independent evaluation. J Clin Laser Med Surg. 2001;19(2):73-81.21.Ahn Y, Oh HK, Kim H, Lee SH, Lee HN. Percutaneous endoscopic lumbar foraminotomy: an advanced surgical technique and clinical outcomes. Neurosurgery. 2014;75(2):124-33; discussion 32-3.22.Nellensteijn J, Ostelo R, Bartels R, Peul W, van Royen B, van Tulder M. Transforaminal endoscopic surgery for lumbar stenosis: a systematic review. Eur Spine J. 2010;19(6):879-86.23.Kambin P, Casey K, O'Brien E, Zhou L. Transforaminal arthroscopic decompression of lateral recess stenosis. J Neurosurg. 1996;84(3):462-7.24.Wen B, Zhang X, Zhang L, Huang P, Zheng G. Percutaneous endoscopic transforaminal lumbar spinal canal decompression for lumbar spinal stenosis. Medicine (Baltimore). 2016;95(50):e5186.25.Lee CW, Yoon KJ, Jun JH. Percutaneous Endoscopic Laminotomy with Flavectomy by Uniportal, Unilateral Approach for the Lumbar Canal or Lateral Recess Stenosis. World Neurosurg. 2018.Figure LegendsFig. 1Five zones of the lateral lumbar spinal canal divided by accurate boundaries.a,bDifferent zones shown in an artificial model in medial and lateral views.cSchematic diagram of five zones. The boundaries of each zones are described in the text. The right four axial CT scanning image shows the different views of cross-sections (the red solid lines) and the labeled regions correspond to each of the zones.Fig. 2a1-a3shows the location and adjoins of zone 1 (presented by blue transparent material) in different views.a4,a5MRI confirmed the hypertrophy of ligamentum flavum inducing nerve root compressed in zone 1.a6Sagittal view of the same region in CT which was not as obvious as MRI images.a7Sagittal view of CT scans after decompression of zone 1 by resecting superior-ventral portion of the superior articular process (SAP) and a part of the inferior articular process (IAP) via percutaneous endoscopic transforaminal decompression (PETD).b1-b3shows the location and adjoins of zone 2 (presented by red transparent material) in different views.b4-b6CT and MRI confirmed the stenosis in zone 2 inducing nerve root compressed.b7,b8Sagittal and axial view of the same region in CT scans showing the decompression of zone 2 by resecting inferior-ventral portion of SAP and a part of IAP via PETD.c1-c3shows the location and adjoins of zone 3 (presented by yellow transparent material) in different views.c4,c5CT and MRI confirmed the posterior apophyseal ring separation (PARS) in zone 3 inducing nerve root compressed.c6,c7Axial and sagittal view of the same region in postoperative CT scans showing the decompression of zone 3 by resecting the lesion viapercutaneous endoscopic interlaminar decompression (PEID).d1,d2shows the location and adjoins of zone 4 (presented by pink transparent material) in medial and lateral views.d3-d5CT and MRI confirmed the occupying osseous lesion in zone 4.d6,d7Axial and sagittal view of the same region in postoperative CT scans showing the decompression of zone 4 by resecting the lesion via PEID.e1,e2shows the location and adjoins of zone 5 (presented by pink transparent material) in medial and lateral views.e3-e5CT and MRI confirmed the stenotic condition in zone 5 casused by hypertropied facet joint compressing the nerve root.e6Axial view of the same region in postoperative CT scans showing the decompression of zone 5 by foraminoplasty via PETD.Fig. 3The angle of trephine and the target region in the two-step foraminoplasty for stenosis in zone 1+2a,banteroposterior (AP) and lateral view in the first stepc,dAP and lateral view in the second step.Fig. 4The distribution of zones involved in all patients.
作者:王玉 孔清泉 陈仲强概述腰椎管狭窄症为60岁以上最常见的脊柱退行性疾患之一[1],1954年Verbiest H[2]系统的提出腰椎管狭窄症的概念并认为间歇性跛行是其典型症状,随着半个多世纪的发展和人们对腰椎管狭窄症认识的不断深入,腰椎管狭窄症的概念已变得越来越完善合理,但仍有许多概念需要继续探讨、统一并在长期临床工作中得到验证。普遍认为,按照解剖位置不同,腰椎管狭窄分为中央型、侧隐窝型和椎间孔型[5]。此分型已经在临床中广为应用,但深究每一类型的定义和特点,我们不难发现,中央型、侧隐窝型狭窄的概念都不严谨。另外“中央管和侧隐窝”解剖范围比较宽泛,不适于指导制定脊柱微创治疗方案。下文将对目前文献提到的“中央管”和“侧隐窝”的解剖以及相对应的“中央管型”和“侧隐窝型”狭窄概念作进一步的阐述和分析,并推荐更为合理和精准的分型。腰椎中央管狭窄的再认识目前认为中央管狭窄是指由椎间盘突出、关节突或黄韧带增生肥厚所导致的椎管中央区域的狭窄,但国内外对中央管的边界并没有明确、统一的严格规定[6],尤其是中央管狭窄诊断层面存在争议,有学者认为中央管狭窄主要发生在椎间盘水平,但腰椎退变主要发生在盘黄间隙及骨性侧隐窝区,因此诊断平面不应仅限于盘黄间隙水平。我们知道,由于神经根逃逸作用,中央管狭窄患者的临床症状与影像学狭窄程度常不成正比。因此,中央管狭窄亦应当是一个影像学或解剖学概念,而“中央管狭窄症”为一临床概念。而到底如何理解“症”的含义,还需要我们进一步讨论明确。“中央管狭窄症”的概念在国内更加受到关注,但无论于国内外中央管的范围及“中央管狭窄症”的定义仍缺乏统一认识[11, 12]。我们认为“中央管狭窄症”是由于椎管中央区(硬膜囊对应区域)狭窄压迫硬膜囊内神经结构从而导致一根或一根以上马尾神经损害而出现的临床症状。“中央管狭窄症”的概念应当从两个方面理解:一方面,当患者出现括约肌障碍(二便功能障碍)或性功能障碍时,必然意味着多根S2或S3神经根受压,而S2、S3神经根在腰椎管内仅存在于硬膜囊中(中央区),因此S2、S3受压时必然可以诊断为“中央管狭窄症”;另一方面,S1及以上神经根(如L4、L5)受压时,则需要根据不同受压位置,给出不同定义。以L4/5单节段狭窄为例,我们发现,L4/5节段狭窄既可以出现L5症状,也可以出现S1症状,如图1[13]。但L5症状的产生是由于L5神经根于L4/5侧隐窝区域受压所致;而S1根在L4/5节段紧贴硬膜囊内侧壁走行,此时S1神经根还位于硬膜囊内,S1神经根症状虽然是由L4/5侧隐窝区压迫所致,但仍然应当诊断为“中央管狭窄症”,患者可表现为同侧多根神经根(L5、S1)受压表现(如图2),也就是说“中央管狭窄症”并不完全由中央管狭窄引起,也可以由侧隐窝狭窄引起,中央管狭窄、侧隐窝狭窄和“中央管狭窄症”、“侧隐窝狭窄症”是相互独立且部分交叉的概念。因此我们认为,应该重新严格定义中央管狭窄症的概念:压迫发生在硬膜囊对应区域,从而产生的相应硬膜囊内的神经根压迫症状,就叫做“中央管狭窄症”。但是,准确区分神经根压迫部位位于侧隐窝区还是中央区对手术治疗方案的选择具有极为重要的意义。图1双神经根受累。A L4/5椎间盘突出向内侧移位(在本图中同时有向下移位)压迫L5和S1神经根;B L5/S1椎间盘突出向外侧移位压迫L5和S1神经根;C L5/S1椎间盘突出向头侧和内侧移位压迫L5和S1神经根;D椎间孔内腰椎间盘突出导致L4和L5神经根均受累。[13]图2 L4/5侧隐窝狭窄致S1神经根受压示意图图3 Ahn[14]提出经皮内镜入路选择标准基于以上分析,我们再重新审视目前腰椎管狭窄症内镜治疗的入路选择原则。之前普遍认“中央管狭窄症”是脊柱内镜手术的禁忌,尤其是黄韧带和小关节突增生所致的中央管狭窄。目前,普遍的观点是椎间孔入路可以处理除中央区以外的狭窄类型,而椎板间入路适用于除椎间孔狭窄以外的其他类型,中央管狭窄仅可以通过椎板间入路解决,如图3[19-21]。目前尚无应用椎间孔入路治疗中央管狭窄的研究。我们认为椎板间入路治疗中央管狭窄仍然有局限性,例如椎板间入路处理合并椎间孔狭窄的患者较困难、某些高龄患者并不能耐受全身麻醉、椎板间入路处理黄韧带、关节突骨化增生肥厚以及对侧腹侧压迫困难等。基于对“中央管狭窄症”概念的充分理解和认识,我们认为椎间孔入路可以很好的解决上述问题,可以用于治疗由侧隐窝狭窄导致的“中央管狭窄症”患者(如图2)。2016年2月至2018年4月期间,我们采用椎间孔入路椎间孔镜手术治疗53例伴有同侧多根症状的单节段腰椎“中央管狭窄症”患者,所有患者术前证实压迫来源于侧隐窝狭窄,平均随访时间13.6月。所有患者平均手术时间116.4±36.8min,平均住院时间6.3±0.69天,总体满意率97.9%。A-B:术前MRI显示腰4/5椎管狭窄,椎间盘突出、黄韧带增厚、关节突增生内聚;C-D:术前CT显示关节突增生内聚,硬膜囊面积减小,双侧侧隐窝狭窄;E-F:双侧PELD术后MRI显示中央椎管区域减压、硬膜囊恢复充盈;F:术后CT显示中央椎管减压,双侧侧隐窝减压,关节突关节保留较好。A-D:术前MRI提示L4椎体滑脱伴L4/5中央椎管狭窄、椎间盘突出、关节突增生内聚双侧侧隐窝狭窄。E(左侧)、F(右侧)、G-F:提示双侧PELD术后侧隐窝减压彻底,关节突关节保留较好。总之,我们应重新理解和认识到腰椎“中央管狭窄”为一解剖概念,“中央管狭窄症”为一临床概念。我们重新严格定义“中央管狭窄症”的压迫范围应为硬膜囊对应的区域,只有压迫硬膜囊而产生的神经根症状就叫做“中央管狭窄症”,而部分目前认为的“中央管狭窄症”的实质为多根神经根于侧隐窝处致压,此时经皮内镜尤其是椎间孔入路完全可以解决此类患者,并且相对于椎板间入路有着诸多优势。但经皮内镜治疗此类中央型腰椎管狭窄应当把握严格的适应症,严重的“中央管狭窄症”尤其是合并二便或性障碍的患者,选择内镜治疗时应慎重,切不可为了微创而微创,为了达到更充分的减压效果,必要时不得不行开放传统手术。腰椎侧方椎管狭窄的再认识目前,侧隐窝的概念始终没有一个准确、统一、公认的定义,尤其是侧隐窝的具体边界、毗邻都存在许多争议,充分理解侧隐窝的概念及科学的分型是临床诊断及治疗的基础。国内外研究者对腰椎管侧隐窝概念的认识经历了漫长的过程,对其也有诸多不同表述,如:神经根管(radicular canal)、腰神经根沟(Lumbar Radicular Groove)、侧方沟(Lateral Gutter)、侧方椎管(lateral lumbar spinal canal)、关节突下狭窄(Subarticular Stenosis)、侧隐窝综合征(lateral recess syndrome)等[22-24]。具有里程碑意义的两个概念一个是“神经根管”[22-24],其定义为由神经根从硬膜囊分出开始到离开椎管所经过的通道。第二个概念就是“侧隐窝”,Epstein[25]最先提出的侧隐窝的概念定义为关节突下内半侧覆盖的区域(即狭义的骨性侧隐窝),Cric[26]认为侧隐窝应为上关节突前方对应的区域(包括狭义的骨性侧隐窝(或广义骨性侧隐窝上部)及关节突前方的部分盘黄间隙);Spivak[29]认为的侧隐窝为硬膜囊外侧到椎弓根内侧的全部区域,此区域便是广义的骨性侧隐窝概念。虽然侧隐窝的概念相对于神经根管有了明确的边界和毗邻,但不同人对侧隐窝的理解仍然不同。直至1988年,Lee C.K[27]将上述混乱的概念名词统一,提出侧方腰椎管区域(Lateral Lumbar Spinal Canal,LLSC)的概念,并根据该区域常见狭窄部位病理解剖的不同进一步分为:入口区,中间区,出口区。LEE的分型目前为大部分学者接受和在临床中应用,但我们认为依然存在很多表述不明确之处[30]。2018年我们在大量临床研究和解剖数据分析的基础上,沿用“腰椎侧方椎管(LLSC)”的概念并重新明确定义,并提出“腰椎侧方椎管”的华西分型指导手术决策,得到了业界认可[17]。我们认为“腰椎侧方椎管”是位于腰椎管侧方的狭长区域,包括了腰椎神经根走行的全部区域。腰椎侧方椎管根据解剖和病理特点应当分为五个区域:盘黄间隙(1区)、骨性侧隐窝上部(2a区+2b区)、骨性侧隐窝下部(3区)、椎间孔内侧区(4区)、椎间孔区(5区)、椎间孔外区(6区),如图4。我们对每个区域的骨性标志、起始点、毗邻都做了明确界定[17]。1区、2区、5区为腰椎应力集中的区域,因此也是退变最常发生的区域,我们发现,81.5%的LLSC狭窄患者发生在1区和(或)2区。而3区、4区为骨性环结构,无应力集中,因此很少发生退变性狭窄,主要致压原因为游离椎间盘突出、骺环离断、后纵韧带骨化及峡部裂性腰椎滑脱等。6区为椎间孔外侧区域,是极外侧椎间盘突出最常发生的致压区域。椎间盘纤维环附着点位于下位椎体上缘3mm范围内,因此我们将此部分命名为2a区(纤维环附着处),2区剩余部分为2b区。2a区由于纤维环附着点的存在,成为神经根受压最常见的部位,同时也是内镜手术术中重点探查和减压的区域。图4腰椎侧方椎管华西分型示意图(L5神经根的左侧LLSC分区)我们定义的腰椎侧方椎管首先是一个稳定的区域,它不随神经根走行的变异而改变,并且有明确的骨性标志,可以在术前影像学辅助下和在术中进行定位诊断。其次,腰椎侧方椎管的华西分型是一个符合脊柱运动功能特点的分型方法,更重要的意义在于指导手术方案制定。基于此分型指导治疗方案选择:2、3、4区为骨性结构包围成的区域,空间大小极少会随体位变化而改变,因此,发生于此区域的神经根压迫必须保证术前精确定位和术中充分减压。而某些位于1区、5区的狭窄患者,由于致压因素常为椎间盘、黄韧带等软性结构,部分患者可行间接减压治疗,如OLIF等。经皮内镜入路选择时,术前明确压迫定位也有着极高的指导意义:由于3、4区由骨性环构成,由于椎弓根遮挡,椎板间入路更加便捷;相反,累及1、5、6区的狭窄优先选择椎间孔入路。另一方面,此分区对术中减压要求也有重要指导意义,例如1区狭窄主要为软性压迫,腹侧减压格外重要;2区狭窄尤其是2a区狭窄,主要为背侧骨性压迫,背侧关节突和腹侧纤维环附着处彻底、充分的减压是保证手术疗效的关键因素,2a区的提出提醒我们应对纤维环附着点减压的额外重视。因此,我们只需要在术前明确LLSC狭窄的致压部位,在分型的指导下选择最优手术方案、关节突成型区域和术中减压重点,从而保证术后疗效。任何新兴微创技术的出现和发展都离不开人们对脊柱结构、生物力学特点、发病机制的深入理解和思考,人们对腰椎管狭窄症经过半个多世纪的不断认识、发现和发展,已经取得了长足的进步。但是,人们对椎管内区域和“中央管”、“侧隐窝”的认识仍然存在许多不足和可探讨之处,以上是我们对以上问题的一些新的认识和浅见,有待广大脊柱医师共同努力验证和探讨,以创造腰椎管狭窄症微创治疗更好的明天!参考文献:1.Katz JN, Harris MB. 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