【Abstract】：Objective
To explore the application value of total laminectomy and repositioning technique for the treatment of spinal cord tumors.
Methods
We retrospectively analyzed the clinical data of 22 cases of spinal cord tumors treated by microsurgery from September 2010 to June 2012 in our hospital, adopting total laminectomy technique, microneurosurgery technique to isolate and remove spinal cord tumors, and laminar repositioning and fixation.
Results
Among the 22 patients, 20 cases had total resection of the tumor and 2 cases had most of the tumor removed. 21 patients had improved postoperative muscle strength and sensory impairment, and 1 patient had decreased postoperative muscle strength. Postoperative CT review of the spine from 3 months to 6 months showed good local anatomical repositioning of the vertebral plate in the operated segment, no subluxation in position, and good fusion of the resected plate with the adjacent vertebral plate.
Conclusion
The laminotomy repositioning technique restored the anatomical structure of the spinal canal, ensured the stability of the spine, and effectively prevented the occurrence of postoperative complications of spinal cord tumors.
Spinal cord tumors are common tumors of the adult central nervous system and mostly require posterior surgical treatment. Most neurosurgical centers remove all the spinal processes and laminae of the corresponding segments, leaving the posterior spinal column structures missing after surgery, which affects the stability of the spine to varying degrees, especially for adolescent patients who are still in the growth stage. With the clinical application of three-dimensional CT and magnetic resonance imaging (MRI) and the continuous development of microinvasive neurosurgery techniques, the diagnosis and treatment of spinal cord tumors have been significantly improved, the way of removing the vertebral plate has been greatly improved, and the tumor separation and resection techniques have been significantly improved compared with those in the past, while with the gradual involvement of neurosurgery in the field of spinal internal fixation, there is a new understanding of spinal stability and postoperative reconstruction of the spinal canal to The postoperative reconstruction of the spinal canal to restore good spinal anatomy and reduce complications has received much attention. The application of new surgical instruments and internal fixation materials has made a more scientific and secure total laminectomy repositioning technique possible. From September 2010 to June 2012, the author used a high-speed grinding drill to slot 22 spinal cord tumors, remove the corresponding laminae intact, reposition and fix them after surgery, and reconstruct the anatomical structure of the spinal canal with good results.
1.Data and methods
1.1 General information
There were 22 cases in this group, 15 males and 7 females, aged 12 to 70 years old, with an average of 45 years old. All had different degrees of neurological dysfunction, including 20 cases of sensory dysfunction (limb numbness, pain, fasciculation), 15 cases of motor dysfunction (muscle weakness, limb paralysis), 1 case of sphincter dysfunction (urinary and fecal dysfunction), and 8 cases of more than 2 kinds of dysfunction. The duration of the disease ranged from 3 months to 2 years. Radiographs, CT and MRI were performed in 3 cases of cervical segment, 10 cases of thoracic segment and 9 cases of lumbar segment. Two cases were intramedullary, 18 cases were extramedullary intradural, and 2 cases were epidural. The tumor sizes ranged from 25px to 112,5px, and a total of 22 tumor specimens were resected. All of the cases in this group were aged 18-55 years old, in good health before surgery, without organic diseases requiring medical treatment, all were primary tumors in the spinal canal, and metastatic tumors were excluded. There was no preoperative physiological curvature straightening of the spine and lateral deformity, and all of the surgical procedures took a posterior median approach.
1, 2 Methods
1,2,1 Main instruments.
4-hole cranial connection piece and 5-mm self-tapping screws produced by Shenzhen Biobridge Company.
1, 2, 2 Surgical methods
Intravenous compound anesthesia with tracheal intubation, methylprednisolone 1000mg was administered during skin incision, and the sedation time should be more than two hours. The posterior median approach was performed, and a posterior median straight incision was made with the lesion segment as the center, separating the paravertebral muscles on both sides. In the medial aspect of the articular eminence, the vertebral plate is slotted bilaterally with a 1 mm diamond drill, and the plate is gently pried with a prying plate, and after the plate is severed, the supraspinous and interspinous ligaments of the upper and lower segments are excised and the plate is removed completely (see Figures 1 and 2). The dura is cut longitudinally and suspended to both sides. Intramedullary tumors require longitudinal dissection of the soft spinal membrane and fixation to the dura with titanium clips to both sides. This completes the full exposure of the spinal cord. The tumor is excised using a microneurosurgical technique [1]. The dura mater was closed with continuous sutures. After completion of the intradural surgery followed by repositioning of the vertebral plate and reconstruction of the spinal canal, a 4-hole cranial connecting piece was taken and fixed to both sides of the removed vertebral plate with 5-mm self-tapping titanium nails, (see Figure 3) to reposition the vertebral plate, and the other end of the connecting piece was fixed to the corresponding vertebral plate with self-tapping screws. Care is taken to shape the connection piece to the appropriate angle in advance to correspond to the curvature of the corresponding vertebral plate. The titanium nails are fixed securely and symmetrically on both sides, with two laminae and 6-8 nails per vertebral plate. (See Figure 4.) After repositioning and fixing the lamina, a drain is placed, the paravertebral muscle is sutured, and the subcutaneous tissue and skin are sutured in sequence.
Figure 1 The vertebral plate incision position Figure 2 The complete removal of the vertebral plate Figure 3 The four-hole cranial connection piece was taken and fixed on both sides of the removed vertebral plate with 5-mm self-tapping titanium nails Figure 4 The repositioning of the vertebral plate was completed Figure 5 The review CT 3 days after surgery showed satisfactory anatomical repositioning of the vertebral plate Figure 6 The second operation six months after surgery showed good repositioning and fusion of the vertebral plate
2.Results
The operation time ranged from 2,3 hours to 5,3 hours, with an average of 3,25 hours, and the bleeding ranged from 50 ml to 400 ml, with an average of 150 ml, and no intraoperative blood transfusion in all cases. The average hospital stay was 13.5 days. The postoperative pathological results showed 10 cases of nerve sheath tumor, 10 cases of spinal meningioma and 2 cases of ventricular meningioma. The postoperative muscle strength and sensory deficits were all improved to varying degrees compared with the preoperative period, with six patients having an increase in muscle strength of two or more levels, and 15 patients having significantly more sensitive sensory deficits (e.g., pain, temperature, position, and two-point discrimination) than the preoperative period. one patient with sphincter dysfunction was unable to recover the function of the spinal cord after surgery due to late consultation. All cases were free of surgery-related complications such as infection and bleeding, and there were no fatal cases. Postoperative CT review of the spine 3 days after surgery (Figure 5) showed that the local vertebral structure of the operated segment was stable, with no cases of laminar loosening or laminar collapse, and the resected lamina was well aligned with the adjacent lamina. Postoperative follow-up was 1-2 years, and MRI results were reviewed six months after surgery and showed complete resection of the tumor in 20 cases, with two cases of spinal meningioma located in the lateral anterior aspect of the spinal cord obtaining only a majority resection and a small amount of tumor remaining at the dura mater at the base of the tumor. All cases were followed up for more than six months, and two of them had tumor recurrence one year after surgery and were surgically resected again, with good intraoperative fusion of the vertebral plate (Figure 6).
3.Discussion
1.Clinical significance of laminectomy repositioning
The traditional surgical approach for intravertebral tumor is the posterior median approach, which requires all the spinous processes of the vertebral plate to be bitten off with biting forceps to completely reveal the spinal cord, and the structure of the posterior column of the spine is damaged to varying degrees. The loss of the attachment point of the spinous process will lead to the loss of muscle strength, which will accelerate the onset of spinal degeneration. How to accomplish a good visualization of the spinal cord and smooth removal of spinal cord tumors while preventing spinal scar adhesions and spinal stenosis (medically induced stenosis) and effectively maintaining the biomechanical stability of the spine has become a focus of attention for neurosurgeons and orthopedic surgeons [2]. Laminectomy resurfacing surgery restores the normal anatomy of the spine and maintains spinal stability, while the resurfaced lamina separates the spinal cord from the muscular soft tissues, minimizing the incidence of spinal scar adhesions. The repositioned lamina also provides a good anatomical relationship for secondary surgery, reducing the risk of injury to the spinal cord due to separation of scar adhesions. This shows that laminar repositioning is essential. None of the 22 cases we followed had complications such as dural rupture, spinal nerve root and spinal cord injury, which proves that this procedure is safe and reliable.
2.How to choose the internal fixation material for laminectomy repositioning
The purpose of laminectomy repositioning is to reconstruct the normal anatomy of the spinal canal and restore the integrity and stability of the spine, and to avoid the lamina from falling into the spinal canal during repositioning. Some people have received good clinical results using titanium plates and titanium nails to fix the spinous process plate complex [3-5]. Choosing a familiar and reliable fixation material is the key to successful surgery. For neurosurgeons, we are very familiar with cranial connection plates and titanium nails for fixation of the skull, so we have an inherent advantage in using cranial connection plates and titanium nails for fixation of the vertebral plate. Not only is it easy to obtain materials, easy and reliable fixation method, and familiar with fixation technique, but also the postoperative MRI is not affected. In all cases in this group, no collapse of the repositioned lamina into the spinal canal, posterior convexity deformity of the spinal canal, or medically induced spinal stenosis was observed, and there was no dislodgement or displacement of the fixation material; the side of the lamina section close to each other was completely osseointegrated and bone scabs were formed, and the other side of the lamina section with a larger gap formed fibrous healing. Therefore, the method of laminectomy, joint piece and titanium nail fixation to reconstruct the bony structure of the posterior column of the spinal canal is simple, safe and reliable, which can achieve ideal anatomical repositioning and avoid laminectomy-related complications, and is worthy of promotion and application by spinal cord neurosurgeons.
3, laminectomy repositioning surgery indications and surgical operation skills.
Surgical indications: In principle, for all intravertebral tumors, as long as the vertebral articulation is not destroyed and the stability of the spine is not changed, the laminectomy repositioning technique can be used.
Surgical operation technique: In all cases in this group, preoperative injection of Melan on the spinous process of the operated segment under X-ray can achieve accurate localization of the tumor, reduce the intraoperative use of C-arm fluoroscopy, and decrease the operation time, as well as reduce the incidence of infection. The extent of laminectomy should include the upper and lower poles of the tumor, and when removing the lamina, try to preserve the bilateral articular processes to maintain better stability of the spine. According to the normal anatomical shape of the vertebral canal, the connecting piece used for fixation should be shaped according to the surface shape of the vertebral canal beforehand, that is, the connecting piece should be bent to ensure that the connecting piece is intact on the surface of the vertebral plate without any tension, which can prevent the vertebral plate from sinking and reserve enough space for the vertebral canal, and at the same time prevent the vertebral plate from being excessively posteriorly convex, which affects both the appearance and the healing of the vertebral plate. Although the two-hole connection piece can reduce the cost, it can easily lead to the rotation and subsidence of the vertebral plate, and because the bone quality of the vertebral plate is relatively soft compared with that of the skull, it is difficult to form a stable and reliable fixation with one screw, therefore, try to choose a four-hole connection piece, and choose two titanium nails for fixation on one side as far as possible, which can prevent rotation and displacement of the vertebral plate and affect the fixation effect.
When removing multiple laminae at one time, the supraspinous and interspinous ligaments of the adjacent laminae should be preserved as much as possible, which is beneficial to the stability of the posterior spinal column structure. When using the grinding drill, choose a thin, slender drill bit, so that the bone defect caused by the removal of the vertebral plate is less, which is conducive to the reset and fusion of the vertebral plate after surgery; the first use of the grinding drill should be done while cutting the vertebral plate, while using the meningeal stripper to probe the depth of the vertebral plate removal, to prevent the removal of the vertebral plate is too deep, resulting in dural and even spinal cord injury, once the full layer of the vertebral plate is cut, you can probe the tougher ligament under the vertebral plate, at this time to complete the The removal of the lamina should be carried out in the direction from caudal to cephalic, firstly removing the interspinous ligament of the last vertebral plate, lifting the last vertebral plate, freeing the adhesions between the lamina and the ligamentum flavum in turn, lifting the lamina while freeing it, and finally cutting the adhesions between the most cephalic vertebral plate and the ligamentum flavum with scissors, removing the corresponding diseased segment including the spinous process, supraspinous ligament, interspinous ligament and lamina as a whole at one time, so that the spinous ligament The composite structures are all preserved, and the complete lamina is anatomically repositioned to preserve the stability of the spine to the maximum extent [6-7].
In conclusion, the use of total laminectomy technique not only ensures full exposure of the surgical field, but also restores the original anatomical structure of the spinal canal, achieves anatomical repositioning of the spine, restores the stability of the spine, and prevents the occurrence of complications such as postoperative spinal cord compression and scar adhesions compressing the spinal cord and nerve roots, which is a simple, reliable, economical and practical method with clear clinical application, and is worthy of popular clinical application by the majority of neurosurgeons.