Method for percutaneous endoscopic decompression of foraminal and extraforaminal stenosis at level of l5-s1 and outgoing l5 root from posterolateral extraforaminal access

Abstract

FIELD: neurosurgery.SUBSTANCE: used for percutaneous endoscopic decompression of foraminal and extraforaminal stenosis at the L5-S1 level and the exiting L5 root from the posterolateral extraforaminal approach. The entry point is determined on the skin at the most lateral point located on the line of the sacroiliac joint. A guide needle is placed on the superior articular process along the line of the inferior endplate of the overlying vertebra. Under X-ray control, a working cannula is placed from the posterolateral approach extraforaminally to the middle of the superior articular process to the exiting root. Under visual control, partial resection of the superior articular process is performed, starting from its middle, and resection of osteophytes in the extraforaminal zone. When performing decompression of the exiting root in the foraminal and extraforaminal zones, the working cannula is displaced by stretching the skin.EFFECT: method ensures the performance of a complete, visually controlled and minimally traumatic decompression without the need for instrumentation of the spinal motion segment, which reduces the risk of developing instability of the spinal motion segment and post-operative spine syndrome, and also promotes early postoperative activation and recovery of the patient due to the optimal access vector, minimal risk of damage to nerve structures while ensuring a good view of the surgical field and complete decompression of the spinal root.1 cl, 1 dwg, 1 ex

Description

[0001] The invention relates to medicine, namely to neurosurgery, and can be used for foraminal and extraforaminal stenosis of the lumbar spine with compression of the outgoing L5 root.

[0002] The traditionally accepted microsurgical treatment for lumbar foraminal stenosis involves facetectomy with fixation of the spinal motion segment, or foraminotomy with medial facetectomy through an interlaminar approach. Total facetectomy allows for effective decompression of the spinal nerve root; however, it often leads to iatrogenic segmental instability and the development of back pain, which subsequently requires fixation of the operated spinal motion segment, and in turn, contributes to the development of adjacent segment syndrome. Foraminotomy with medial facetectomy from the interlaminar approach is characterized by a limited overview, is performed without clear visualization of the exiting root, and in the case of foraminal stenosis in the lateral part of the intervertebral foramen and extraforaminal stenosis, it completely excludes the possibility of decompression of the exiting root [1) Reulen HJ, Pfaundler S, Ebeling U.The lateral microsurgical approach to the “extracanalicular” lumbar disc herniation. I: a technical note. Acta Neurochir (Wien). 1987;84(1-2):64-67. 2) Garrido E, Connaughton PN. Unilateral facetectomy approach for lateral lumbar disc herniation. J Neurosurg. 1991;74(5):754-756. 3) Jenis LG, An HS. Spine update. Lumbar foraminal stenosis. Spine (Phila Pa 1976). 2000;25(3):389-394. 4) Epstein NE. Foraminal and far lateral lumbar disc herniations: surgical alternatives and outcome measures. Spinal Cord. 2002;40(10):491-500].

[0003] A method of decompression of the intervertebral foramen with preservation of the facet joint from a microsurgical paravertebral approach is known. It was first described by Reulen et al. in 1987 and Wiltse and Spencer in 1988. This technique allows access to the foramen with minimization of trauma to the intervertebral joint and postoperative back pain [Kunogi J, Hasue M. Diagnosis and operative treatment of intraforaminal and extraforaminal nerve root compression. Spine (Phila Pa 1976). 1991;16(11): 1312-1320]. According to various authors, this approach has an efficiency of 72% to 83% of observations [1) Epstein NE. Foraminal and far lateral lumbar disc herniations: surgical alternatives and outcome measures. Spinal Cord. 2002;40(10):491-500. 2) Kunogi J, Hasue M. Diagnosis and operative treatment of intraforaminal and extraforaminal nerve root compression. Spine (Phila Pa 1976). 1991;16(11): 1312-1320. 3)Donaldson WF III, Star MJ, Thorne RP.Surgical treatment for the far lateral herniated lumbar disc. Spine (Phila Pa 1976). 1993;18(10):1263-1267. 4)Lejeune JP, Hladky JP, Cotten A, Vinchon M, Christiaens JL. Foraminal lumbar disc herniation. Experience with 83 patients. Spine (Phila Pa 1976). 1994;19(17): 1905-1908. 5)Darden BV II, Wade JF, Alexander R, Wood KE, Rhyne AL III, Hicks JR. Far lateral disc herniations treated by microscopic fragment excision. Techniques and results. Spine (Phila Pa 1976). 1995;20(13):1500-1505. 6)Baba H, Uchida K, Maezawa Y, Furusawa N, Okumura Y, Imura S. Microsurgical nerve root canal widening without fusion for lumbosacral intervertebral foraminal stenosis: technical notes and early results. Spinal Cord. 1996;34(11):644-650. 7)Hodges SD, Humphreys SC, Eck JC, Covington LA. The surgical treatment of far lateral L3-L4 and L4-L5 disc herniations. A modified technique and outcomes analysis of 25 patients. Spine (Phila Pa 1976). 1999;24(12):1243-1246.8) Gioia G, Mandelli D, Capaccioni B, Randelli F, Tessari L. Surgical treatment of far lateral lumbar disc herniation. Identification of compressed root and discectomy by lateral approach. Spine (Phila Pa 1976). 1999;24(18):1952-1957. 9) Chang HS, Zidan I, Fujisawa N, Matsui T. Microsurgical posterolateral transmuscular approach for lumbar foraminal stenosis. J Spinal Disord Tech. 2011;24(5):302-307]. However, according to these authors, a significant proportion of patients experience postoperative leg pain, sensory and motor disturbances, which are the main causes of unfavorable outcomes. Active manipulations in the area of ​​the spinal ganglion and root cause neurological deficit. In addition, limited visibility of the lateral paravertebral approach may result in incomplete decompression of the exiting root [1) Darden BV II, Wade JF, Alexander R, Wood KE, Rhyne AL III, Hicks JR. Far lateral disc herniations treated by microscopic fragment excision.Techniques and results. Spine (Phila Pa 1976). 1995;20(13):1500-1505. 2) Hodges SD, Humphreys SC, Eck JC, Covington LA. The surgical treatment of far lateral L3-L4 and L4-L5 disc herniations. A modified technique and outcomes analysis of 25 patients. Spine (Phila Pa 1976). 1999;24(12):1243-1246].

[0004] A method described in 2003 by Hoogland is known, who proposed performing foraminotomy under fluoroscopic control using special reamers of different diameters without endoscopic visualization [1) Hoogland T: Transforaminal endoscopic discectomy with foraminoplasty for lumbar disc herniation. Surg. Tech. Orthop. Traumatol. 40:55–120, 2003. 2) Morgenstern R. Transforaminal Endoscopic Stenosis Surgery – A Comparative Study of Laser and Reamed Foraminoplasty. European musculoskl. disease 4: 35–40, 2009]. This "blind" foraminoplasty increases the risk of damaging the exiting nerve root in the presence of a significantly narrowed foraminal opening and can lead to excessive, "unnecessary" resection of the facet joint. Furthermore, this foraminotomy is not used for foraminal stenosis but is essentially a surgical step—an access point for subsequent herniation. The authors called this procedure "foraminoplasty."

[0005] A known method is described by Bulyshchenko G.G. et al. [Method of percutaneous lumbar foraminotomy. Bulyshchenko G.G., Gaivoronsky A.I., Svistov D.V., Bannikov S.A., patent for invention RUS 2688733 10 / 12 / 2018]. This method is in many ways similar to the foraminoplasty method described in 2003 by Th. Hoogland. The method involves performing a "blind" foraminotomy under fluoroscopic control without visual endoscopic control and, in essence, is not a foraminotomy used for stenosis of the intervertebral foramen, but represents a stage of the operation for further access to the hernia. The use of this method in cases of severe foraminal and extraforaminal stenosis [Grade 2-3 according to the MRI classification proposed by Seunghun Lee et al.[In 2010,] with a clinical picture of exiting root compression, a complete absence of Kambin's "safety triangle," and a lack of visual endoscopic control appears dangerous due to damage to the exiting root, especially in cases of abnormal spinal root position. Given the lack of visual control of the resection volume, this procedure leads to excessive, "unnecessary" resection of bone and ligament structures.

[0006] The closest to the claimed method is endoscopic foraminotomy proposed by Y. Ahn et al. [Yong Ahn, MD, PhD, Hyun-Kyong Oh, RN, Ho Kim, BS, Sang-Ho Lee, MD, PhD, Haeng-Nam Lee, RN. Percutaneous Endoscopic Lumbar Foraminotomy: An Advanced Surgical Technique and Clinical Outcomes. Neurosurgery 2014, 75:124–133.]. This method involves the sequential installation of a needle, a guidewire, and an obturator into the intervertebral foramen by sliding along the surface of the articular process. Then, after installing the obturator, a working cannula with a beveled end is inserted into the intervertebral foramen and placed on the lower surface of the joint. The authors emphasize that at this stage of the operation, the placement of the working cannula or endoscope in the intraforaminal zone can be painful and dangerous due to the increased risk of damage to the exiting root.Next, using specialized endoscopic burs, the superior articular process is resected until the ligamentum flavum, foraminal ligament, and epidural fat are exposed. The superior articular process is resected from the inferior to the superior pedicle of the vertebra, from the outer to the inner. Subsequently, various endoscopic instruments are used to remove the hypertrophied ligamentum flavum and foraminal ligaments and osteophytes. Radiofrequency coagulation is recommended for coagulation of the remaining ligaments and disc. The end point of the surgery is complete decompression of the exiting nerve root.

[0007] Disadvantages of the prototype:

[0008] - Initially, the obturator is located intraforaminally, which can be painful for the patient and dangerous for the exiting root;

[0009] - The working cannula is initially positioned with its non-beveled end towards the root, which increases the likelihood of its damage;

[0010] - The possibility of developing instability of the spinal motion segment as a result of resection of the superior articular process, since the author performs the resection starting from the lower leg, which inevitably leads to resection of the base of the superior articular process;

[0011] - The described technology does not indicate the use of burs with a curved end and special endoscopic kerrisons, which limits the possibility of medial resection of the facet joint, which is especially important in the presence of additional stenosis of the lateral recessus.

[0012] - The described technology does not indicate the possibility of performing this technology in case of extraforaminal stenosis, which is essential for freeing the outgoing root at the extraforaminal level.

[0013] The invention aims to create a method for minimally invasive percutaneous endoscopic decompression of the exiting spinal root through a posterolateral extraforaminal approach for foraminal and extraforaminal stenosis. This method reduces the risk of exiting root injury and provides visually controlled, minimally sufficient root decompression at the foraminal and extraforaminal levels; eliminates the need for instrumentation of the spinal motion segment; promotes early postoperative patient activation and recovery; and can serve as a preventative measure for spinal motion segment instability and post-surgery syndrome.

[0014] The said technical result in the implementation of the present invention is achieved by the fact that the working cannula is initially installed from the posterolateral approach extraforaminally in the middle of the superior articular process under X-ray control to the outgoing root, which ensures protection of the root from direct damage by the cannula; for installation in the middle of the superior articular process, it is proposed to orientate along the line of the inferior endplate of the overlying vertebra; the beginning of the resection is carried out from the middle of the superior articular process to the apex, which facilitates resection in both the cranial and caudal directions, ensures partial and sufficient resection of the facet joint, thereby preventing the development of instability of the spinal motion segment;To determine the skin incision and entry area, the most lateral point located on the sacroiliac joint line is used. This ensures access to both the foraminal and extraforaminal compression zones and is essential for this method. This is due to the fact that the foraminal zone should be approached primarily through a lateral approach, and the extraforaminal zone - primarily through a posterior approach; using special endoscopic burs with a curved end and endocerrisons, which ensures complete medial and lateral decompression, as well as decompression in "difficult" anatomical zones.

[0015] The method is as follows:

[0016] The surgeries were performed under general anesthesia in the prone position with radiographic control in two projections. The most lateral point located on the sacroiliac joint line is used to determine the appropriate entry point on the skin. This entry point location, in our opinion, is essential, as it allows for access to the foraminal zone primarily through a lateral approach, and the extraforaminal zone primarily through a posterior approach. The access vector then runs along the notch between the lateral eminence of the sacrum and the superior articular process of the S. I .

[0017] A skin incision approximately 7 mm long is made. An 18G needle is inserted under C-arm control toward the target point. Unlike endoscopic transforaminal discectomy, the initial target point here is not the intervertebral disc portion in the "safety triangle" region, but the midpoint of the anterolateral surface of the superior articular process of S1. For placement on the midpoint of the superior articular process, it is suggested to use the line of the inferior endplate of the overlying vertebra as a guide. It should be noted that in foraminal and extraforaminal stenosis, the "safety triangle" is virtually absent, significantly increasing the risk of injury to the exiting nerve root if the working cannula is inserted in this area.Next, the guidewire, dilator, and working cannula are sequentially positioned on the mid-anterolateral surface of the superior articular process of the underlying vertebra, with the bevel toward the exiting nerve root. This position ensures that, after inserting the discoscope, portions of the facet joint and intervertebral foramen are visible. We believe this position is optimal for preventing damage to the exiting nerve root while simultaneously providing good surgical visibility. After removing the dilator, the surgery continues under endoscopic visual control and continuous irrigation with saline. Next, the superior portion of the hypertrophied facet joint is resected, starting from its midpoint, and osteophytes are resected using special burrs under constant radiographic and endoscopic control. A spinal microburr with a flexible tip allows for effective resection.Complete decompression of neural structures requires partial resection of the superior articular process, osteophytes until the ligamentum flavum and epidural fat appear, and, in some cases, the superior edge of the pedicle of the underlying vertebra. Following bone resection, portions of the hypertrophied ligamentum flavum and foraminal ligaments compressing the exiting spinal root are removed using micronizers until the epidural space and dural sac are clearly visualized. Next, by applying skin tension, the working cannula is moved primarily perpendicularly into the extraforaminal zone along the exiting root to the posterolateral edge of the endplate of the overlying vertebra, where the osteophytes compressing the root in the exit zone are located. X-ray control of the working instrument position is performed in the lateral projection. Moderate ventral displacement of the root and resection of the osteophytes are then performed using microinstruments.A radiofrequency coagulator is used for tissue preparation, hemostasis, and tissue modification of the dorsal protruding portion of the annulus fibrosus. A distinctive feature of the proposed surgical technique is the epidural posterolateral extraforaminal approach, which allows for decompression of the exiting root in both the foraminal and extraforaminal zones, as well as partial resection of the superior articular process and osteophytes in the extraforaminal zone. The ultimate goal of the surgery is release and mobilization of the exiting root. Patients are typically mobilized within 2-3 hours, and discharge occurs the same day or the following day.

[0018] The claimed method was developed at Dr. Mereji's Pain Treatment Clinic LLC and underwent clinical trials in the treatment of 25 patients, with the following results obtained.

[0019] We give a clinical example.

[0020] Patient S., born in 1948, was admitted with complaints of pain in the lumbar region radiating along the posterolateral surface of the right leg; numbness and weakness in the right leg. Leg complaints intensify after walking and subside after sitting down. Morning stiffness is noted. The back pain has been observed for a long time with periods of exacerbation and remission. The above-described pain in the right leg has been observed for the past three years. The disease has a progressive course. The patient has not noted any improvement despite conservative treatment. Neurological examination revealed radicular pain with a characteristic radicular pattern in the L5 root area on the right, weakness of the extensor muscles of the right foot (3 points), and hypoesthesia in the innervation zone of the L5 root on the right. Tension symptoms are moderately positive on the right. When examining the lumbar region, straightening of the lumbar lordosis, tension in the back muscles, and palpable pain in the area of ​​the intervertebral joints L5-S1 on both sides are noted.MRI of the lumbar spine revealed absolute foraminal stenosis at the level of L5-S1 on the right, Grade 3 according to the classification of Lee et al., 2010.

[0021] Figure 1 shows a CT scan of the lumbar spine, revealing osteophytes in the extraforaminal zone with compression of the exiting nerve root. The examination was performed before and after surgery: blue arrows indicate osteophytes and foraminal stenosis before surgery (upper three slices), as well as complete decompression of the exiting nerve root after surgery (lower three slices). Radiographs of the lumbosacral spine revealed degenerative scoliosis, and functional testing revealed no signs of instability. A selective transforaminal epidural block of the L5 nerve root on the right was performed in the clinic under X-ray navigation, with a temporary effect, which objectively proves the relationship between leg pain and L5 nerve root compression.

[0022] Diagnosis: Degenerative-dystrophic changes in the lumbosacral spine. Foraminal and extraforaminal stenosis at the L5-S1 level on the right. Compression radiculopathy of L5 on the right. Neurogenic intermittent claudication. Spondyloarthrosis, chronic facet back pain.

[0023] Given the short-term positive effect of the blockade, the patient underwent surgery using the technique described above. Immediately after the surgery, complete regression of radicular pain in the leg was observed, along with a reduction in the severity of hypoesthesia and weakness in the leg and a decrease in back pain. The patient was able to stand upright 3 hours after the surgery and was discharged the following morning. A moderately restricted regimen was recommended, and she returned to her normal daily activities within 2 weeks.

[0024] Use of the claimed method reduces the risk of injury to the exiting root; provides visually controlled, minimally sufficient root decompression in both the foraminal and extraforaminal zones; eliminates the need for instrumentation of the spinal motion segment; promotes early postoperative activation and recovery of the patient; and can serve as a preventative measure for instability of the spinal motion segment and post-operative back syndrome.

Claims

A method of percutaneous endoscopic decompression of foraminal and extraforaminal stenoses at the level of L5-S1 and the exiting L5 root from the posterolateral extraforaminal approach, characterized in that the entry site on the skin is determined at the most lateral point located on the line of the sacroiliac joint; a guide needle is placed on the superior articular process along the line of the inferior endplate of the overlying vertebra; under X-ray control, a working cannula is placed from the posterolateral approach extraforaminally in the middle of the superior articular process to the exiting root; under visual control, partial resection of the superior articular process is performed, starting from its middle, and resection of osteophytes in the extraforaminal zone; during decompression of the exiting root in the foraminal and extraforaminal zones, the working cannula is shifted by stretching the skin.

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