Keywords: RF-Ⅱ internal fixation system; decompression; repositioning; PLIF (trans-posterior intervertebral fusion); lumbar spondylolisthesis/surgical treatment Chen Zhiquan, The First Affiliated Hospital of Henan College of Traditional Chinese Medicine, Orthopedic Injury Treatment Center
Abstract: To explore the treatment of lumbar spondylolisthesis. METHODS: From August 1998 to December 2006, posterior decompression RF-II reset internal fixation with interbody fusion was applied to treat lumbar spondylolisthesis, and the surgical methods were retrospectively analyzed. RESULTS: The postoperative complete resetting rate of slippage was 91.89 (34/37). All 37 cases in this group were followed up for 12-48 months, with an average of 22 months. 36 cases showed good fusion of intervertebral implants, no loss of reset and broken nails, with a fusion rate of 97.30% (36/37); the excellent rate of comprehensive evaluation of clinical efficacy was 94.59 (35/37). Conclusion: RF-Ⅱ system is mainly suitable for the treatment of mild and moderate slippage, and posterior decompression RF-Ⅱ repositioning and internal fixation intervertebral implant fusion is a better method for the treatment of lumbar slippage.
Lumbar spondylolisthesis is mainly divided into lumbar isthmus with lumbar spondylolisthesis (true spondylolisthesis) and degenerative lumbar spondylolisthesis (pseudolisthesis), which is one of the most common causes of lumbar pain. With the continuous improvement in the understanding of the pathological mechanism of the disease and the improvement of the treatment plan, especially the application of various transcatheter internal fixation devices in clinical practice, the efficacy has been significantly improved. In our hospital, from August 1998 to December 2006, 37 cases of lumbar spondylolisthesis were treated with posterior decompression RF-II internal fixation and intervertebral implant fusion with satisfactory results, which are reported as follows.
1. Clinical data
1.1 General data Among the 37 cases, 22 were male and 15 were female, aged 36-64 years old, with an average of 48 years old; the duration of disease ranged from 5 to 62 months, with an average of 21 months. Main clinical manifestations: all patients had intractable lower back pain with radiating pain to the buttocks and lower limbs in 29 cases; intermittent claudication in 24 cases; positive straight leg raising test in 26 cases; partial lower limb muscle weakness in 23 cases; decreased skin pinprick sensation in 25 cases.
1.2 Imaging: All cases underwent lumbar frontal and lateral, double oblique and hyperextension and hyperflexion radiographs. According to the Meyerding grading criteria [1]: 5 cases of Grade I slippage, 28 cases of Grade II slippage, 4 cases of Grade III slippage; 25 cases of L4~5 slippage, 12 cases of L5~S1 slippage. There were 19 cases of isthmic cleft with lumbar slippage; 18 cases of degenerative slippage. Detailed classification is shown in Table 1.
Table 1.
Ⅰ Ⅱ Ⅲ
Degenerative slippage 3 14 1
Isthmic fissure slippage 2 14 3
In all cases, lumbar hyperextension-hyperflexion position radiographs showed significant instability of the relevant segment. 31 cases were scanned by CT: 27 cases of bilateral lateral saphenous fossa stenosis, 23 cases with disc herniation, and 4 cases of unilateral lateral saphenous fossa stenosis. MRI examination of the lumbar spine showed lumbar spinal stenosis in the corresponding segment in 19 cases.
1.3 Surgical method: Patients were placed in prone position, and under continuous epidural anesthesia or lumbar anesthesia, a posterior median incision was made centering on the slipped space to reveal the lower vertebral plate, small articular processes and transverse processes on both sides above the slipped space. Under the supervision of the C-arm machine, the pedicle nails were placed in the slipped vertebrae and the inferior vertebrae (the slipped vertebrae were placed in the pedicle with a thicker thread). In all cases, total laminectomy was used for decompression, and the narrowed lateral saphenous fossa and nerve root canal were enlarged for complete decompression. In cases of significant hyperplastic coalescence of the isthmic fissure and the lesser articular processes, partial or complete resection of the lesser articular processes was performed at the same time to remove the hyperplastic scar tissue of the isthmus, and the nerve roots were fully and completely decompressed. The cauda equina and the corresponding nerve roots are retracted and protected, the anterior degenerated or herniated disc tissue is exposed, and symmetrical incisions are made on the posterior longitudinal ligament and the fibrous ring of the disc, respectively, to thoroughly remove the disc tissue and scrape the cartilage endplates of the upper and lower vertebral bodies. The RF-Ⅱ support rod was installed, and the connection between the lower pedicle nail and the support rod was tightened and locked, and the vertebral space was gradually opened and the slipped vertebral body was restored with the lifting and restoring nail as the support point. After the RF-II system was fixed reliably, a full-thickness iliac bone block was taken at the posterior superior iliac spine and two full-thickness iliac bone blocks (about 10~11mm high and 25~30mm long) with 3 sides of cortical bone were implanted from both sides. After the bone grafting, the bone graft was fixed with mild compression by RF-II system compression function to prevent the bone graft from prolapsing or moving. After the nerve root canal and spinal canal were thoroughly decompressed and the internal fixation was firmly fixed and reliable, the operation was ended by flushing, hemostasis, placement of negative pressure drainage, and closure of the incision layer by layer.
1.4 Postoperative treatment: antibiotics were routinely applied after surgery, the negative pressure drainage tube was removed after 24-48 hours, functional exercises for the lumbar back and abdominal muscles were performed after 1 week, and the patients were gradually taken out of bed under the protection of lumbar brace after 4-6 weeks. All patients wore a lumbar support for 6 months after surgery and were prohibited from lumbar flexion and rotation activities.
1.5 Treatment results: There was no nerve injury or infection in this group of cases, and the incision Ⅰ/nail healed. Postoperative review radiographs showed that 34 cases of slipped vertebrae were completely reset and 3 cases of slipped vertebrae were partially reset (2 cases of preoperative Ⅲ degree slippage and postoperative residual Ⅰ degree slippage; 1 case of preoperative Ⅱ degree slippage and postoperative Ⅰ degree slippage), and the rate of complete reset of slippage was 91.89 (34/37). After surgery, the patients’ original symptoms were improved to different degrees, and according to the comprehensive evaluation standard of clinical efficacy [2], 31 cases were excellent, 4 cases were good, and 2 cases were acceptable, with an excellent rate of 94.59 (35/37). Follow-up 12~48 months, average 22 months, 36 cases showed good fusion of intervertebral implants, no reset loss and broken nail, fusion rate of 97.30% (36/37); 1 case did not fuse and had a fracture of the superior pedicle nail rod connection, from postoperative Ⅰ degree loss to Ⅱ degree (this patient was Ⅲ degree true slippage, age was 64 years old, with slight osteoporosis).
2. Discussion.
Lumbar spondylolisthesis is one of the most common causes of lumbar instability and low back pain, and for those whose non-surgical treatment is ineffective or has poor results, most scholars advocate the use of repositioned internal fixation and fusion to restore the stability of the lumbar spine and the biomechanical function of the lumbosacral region, release the stenosis of the spinal canal and intervertebral foramen, eliminate neurological symptoms [3], and reconstruct the normal sequence of the spine, and repositioning and fixation of the slipped vertebrae is the basis for the treatment of lumbar spondylolisthesis [4 ] [5] and should also be considered as routine in the treatment of lumbar spondylolisthesis [6]. Therefore, the ideal surgical treatment should include decompression of the compressed nerve, repositioning of the slipped vertebrae, and fusion with the adjacent vertebrae [7].
The symptoms of low back pain in patients with lumbar spondylolisthesis are mainly caused by the compression of the nerve roots or cauda equina by the growth of peri-vertebral tissue after vertebral body slippage [8], so complete nerve root decompression is the key to alleviate clinical symptoms and prevent postoperative pain. Decompression should not be traditional decompression by removing the vertebral plate, but should be centered on the small joints, thoroughly removing the bilateral upper and lower articular processes and all pathological tissues secondary to the small joints as the core, thoroughly exposing the spinal membrane and bilateral nerve roots [4], and should focus on clearing the diseased intervertebral foramen and the isthmus of the hyperplastic fibrocartilage scabs and thoroughly releasing the compressed nerves, which on the one hand can reduce the strain injury to the nerve roots during repositioning, and on the other hand sufficient decompression also On the one hand, it can reduce the strain on the nerve roots during repositioning, and on the other hand, adequate decompression can facilitate repositioning [8].
Although it is still controversial whether lumbar spondylolisthesis needs to be repositioned, most scholars believe that good repositioning will undoubtedly improve the rate of spinal implant fusion [9]. Since lumbar spondylolisthesis can lead to a significant increase in lumbosacral shear stress, it is not necessary to deliberately pursue perfect anatomical repositioning during surgery, but at least the lumbar spine shear stress should be restored to physiological level to achieve a higher fusion rate [10], and it is also better to eliminate the strain of the slipped vertebral body on the paravertebral soft tissues and the cauda equina and ligaments in the spinal canal, restore the volume of the spinal canal, and enable the cauda equina and nerve roots to be further decompression of the cauda equina and nerve roots.
The ultimate goal of lumbar spondylolisthesis surgery is to achieve bony fusion and long-term stability of the intervertebral space [11]. Most scholars now believe that the application of internal fixation can achieve high fusion rates and long-term clinical outcomes [12]. However, the effect of any instrumented fixation is temporary, and only bone graft fusion can achieve reconstruction and maintain long-term stability of the spine. According to the Denis three-column theory, the vertebral body and intervertebral disc bear most of the load of the spine; therefore, intervertebral bone graft fusion is the most biomechanical requirement that can restore the intervertebral space height and the physiological anterior convexity of the lumbar spine, provide intervertebral longitudinal support, reduce the postoperative loss of intervertebral space height, and improve the fusion rate [13]. A study by Dick Nguyen et al [14] also confirmed that PLIF (transforaminal posterior interbody fusion) has a higher rate of osseointegration, lower rate of internal fixation failure, less loss of slip correction, and a lower incidence of late chronic lower back pain than PLF (posterior posterolateral fusion).
RF-Ⅱ internal fixation system is easy to operate, has reliable bracing and compression function, the application of lifting and repositioning nail can effectively and safely reset the slipped vertebral body, restore the normal spinal force line and lumbosacral stability, effectively complete the decompression of cauda equina and nerve root, and relieve the symptoms; through stronger internal fixation and bracing and compression function, prevent the displacement of bone graft and promote bone fusion, improve the fusion rate of bone graft. RF-Ⅱ system has been preset with different bracing angles (10°, 15°, etc.), and the RF-Ⅱ system can be selected according to the different lumbosacral angles of patients. The satisfactory clinical results achieved in our hospital also confirm that posterior decompression RF – II internal fixation intervertebral implant fusion is a better method for the treatment of lumbar spondylolisthesis.
According to our clinical experience and application, the RF-Ⅱ system is mainly suitable for the treatment of mild and moderate slippage, and the Dick-Hou device developed by Professor Hou Shuxun is still appropriate for severe slippage, which has a better repositioning and fixation effect on severe slippage [9], and only two of the four cases of III degree slippage in this group have been completely repositioned. In our group, one case of non-fusion of bone graft after surgery was related to the patient’s age and osteoporosis, and also to the insufficient amount of bone graft in the early surgery, and no more non-fusion of bone graft and broken nail occurred after improvement.
References
1. Meyerding H. Low backache and sciatic pain associated with spondylolisthesis and protruded intervertebral clisc: incidence, significance and treatment. J Bone Joint Surg(Am),1947,29:461-470.
2. Zou D.W., Hai C., Ma H.S., et al. Treatment of severe lumbar spondylolisthesis[J]. Chinese Journal of Orthopaedics,1998,18(5):261-263.
3. Rao Shucheng, ed. Surgery of the spine [M]. Beijing: People’s Health Publishing House, 1993, 413-426.
4. Zou Dewei, Hai Chung, Ma Huasong, et al. Treatment of moderate lumbar spondylolisthesis[J]. Chinese Journal of Orthopaedics,1998,18(4):259-260.
5. Hong T L,Tang T Y,Dong T H. Clinical significance of segmental instability in the surgical treatment of spondylolisthesis[J]. Chinese Journal of Orthopaedics.1996,16(5):412-413.
6. Hohmann F,Sturz H. Differential indications for lumbosacral fusion and reposition oposion in sponclilolisthesis[J].Orthopacle,1997,26(7):781-789.
7. Hou Shuxun. Correctly grasping the treatment principles of lumbar spondylolisthesis[J]. Chinese Journal of Spinal Cord,1999,9(4):183.
8. Huang P, Liu P T, Hong Q, et al. DRFS pedicle screw system for lumbar spondylolisthesis[J]. Chinese Journal of Spinal Cord,2003,13(12):744-745.
9. Shi YAM, Hou SHuxun, Li L, et al. Design and clinical application of the single-arm suspension lumbar spine slip repositioning fixator (HOIST device)[J]. Chinese Journal of Orthopaedics.2000,20(12):732-734.
10. Chen L, Tang T, Yang H L. Long-term efficacy of Steffee surgery for collapsed lumbar spondylolisthesis [J]. Chinese Journal of Orthopaedics.2001,21(3):163-166.
11. Fan Shunwu, Xiangqian, Zhang Hongjun, et al. The value of intervertebral space sparing in the repositioning and fusion of lumbar spondylolisthesis[J]. Chinese Journal of Orthopaedics.2006,26(2):105-109.
12. Xi YM, Jia LSh. Problems related to the surgical treatment of degenerative lumbar spondylolisthesis[J]. Chinese Journal of Spinal Cord. 2006,16(1):65-67.
13. Proceedings of the National Symposium on Degenerative Disorders of the Lumbar Spine [J]. Chinese Journal of Orthopaedics. 2006,26(10):711-716.
14. A comparison of the efficacy of PLF and PLIF surgery in the treatment of lumbar spondylolisthesis [J]. Chinese Journal of Spinal Cord. 2004,14(3):156-160.