Split Spinous Processes Research Articles

Unilateral transforaminal lumbar interbody fusion through a modified hemilateral spinous process-splitting approach.

To describe unilateral transforaminal lumbar interbody fusion (TLIF) via a modified hemilateral spinous process-splitting (MHSPS) approach and determine its effectiveness. Sixty-five consecutive patients with the lumbar degenerative disease who underwent MHSPS TLIF between August 2020 and July 2021 were retrospectively analyzed. Japanese Orthopedic Association (JOA) score and visual analog scale (VAS) scores for back and leg pain were evaluated before surgery and at the last follow-up. Postoperative paraspinal muscle atrophy was evaluated on axial T2-weighted magnetic resonance imaging. Mean JOA score increased from 13.6 ± 3.21 before surgery to 24.72 ± 3.34 at last follow-up (p < 0.001). The mean recovery rate was 68.2% ± 5.68%. Clinical outcome was excellent in 22, good in 35, and fair in 8 patients. The VAS score for low back pain was significantly lower at the last follow-up than before surgery (1.18 ± 0.99 vs. 3.09 ± 1.35; p < 0.001). The VAS score for leg pain was also significantly lower at the last follow-up than before surgery (1.13 ± 0.91 vs. 6.61 ± 1.23; p < 0.001). The mean paraspinal muscle atrophy rate did not significantly differ between the symptomatic side (6% ± 3.8%) and asymptomatic side (4.8% ± 3.3%) at last follow -up (p = 0.071). MHSPS TLIF is an effective minimally invasive surgical treatment for selected types of degenerative lumbar disease. This technique can achieve effective spinal decompression and interbody fusion. Its advantages include direct and adequate visualization, vast surgical working space, short operation time, and minimal muscle injury.

Clinical outcomes of transforaminal lumbar interbody fusion using a modified posterior spinous process-splitting approach for lumbar degenerative or isthmic spondylolisthesis: a prospective cohort study.

In the conventional posterior approach to the lumbar spine for transforaminal lumbar interbody fusion (TLIF), the paravertebral muscles are stripped from the spinous process. The authors developed a novel surgical procedure in which TLIF was performed via a modified spinous process-splitting (SPS) approach that enabled the preservation of the attachment of the paravertebral muscles to the spinous process. The SPS TLIF group comprised 52 patients with lumbar degenerative or isthmic spondylolisthesis who underwent surgery using a modified SPS TLIF technique, whereas the control group comprised 54 patients who underwent conventional TLIF. Compared with the control group, the SPS TLIF group had a significantly shorter operation time, smaller intra- and postoperative blood loss volumes, and shorter hospital stay and time to ambulation (p < 0.05). The SPS TLIF group had a lower mean visual analog scale score for back pain than the control group on both postoperative day 3 and at 2 years postoperatively (p < 0.05). Follow-up MRI showed changes in the paravertebral muscles in 46 of 54 patients (85%) in the control group and 5 of 52 patients (10%) in the SPS TLIF group (p < 0.001). This novel technique may be a useful alternative to the conventional posterior approach for TLIF.

Midterm Outcomes of Muscle-Preserving Posterior Lumbar Decompression via Sagittal Splitting of the Spinous Process: Minimum 5-Year Follow-up.

To overcome several disadvantages of conventional laminectomy for degenerative lumbar spinal stenosis (DLSS), several types of minimally invasive surgery have been developed. The purpose of the present study was to report the clinical and radiological mid-term outcomes of spinous process-splitting decompression (SPSD) for DLSS. Seventy-three consecutive patients underwent SPSD between September 2014 and March 2016. Of these, 42 (70 segments) who had at least 5 years of follow-up were analyzed retrospectively. The visual analog scale for back pain and leg pain, Oswestry disability index, and walking distance without resting were scored to assess clinical outcomes at the preoperative and final follow-up. A subgroup analysis was performed according to the union status of the split spinous processes (SPs). For radiological outcomes, slip in the neutral position as a static parameter, anterior flexion-neutral translation, and posterior extension-neutral translation as a dynamic parameter were measured before and at the final follow-up after surgery. Spinopelvic parameters were also measured. Reoperation rate at the index levels was investigated, and predictive risk factors for reoperation were evaluated using multivariate logistic regression. Survival analysis was performed with reoperation as the endpoint to estimate the longevity of the SPSD for DLSS. All clinical outcomes improved significantly at the final follow-up compared to those at the initial visit (p < 0.05). The clinical outcomes did not differ according to the union status of the split SP. There were no cases of definite segmental instability and no significant changes in the static or dynamic parameters after surgery. Sacral slope and lumbar lordosis increased, and pelvic tilt decreased significantly at the follow-up (p < 0.05), despite no significant change in the sagittal vertical axis. The mean longevity of the procedure before the reoperation was 82.9 months. Five patients (11.9%) underwent reoperation at a mean of 52.2 months after the SPSD. There were no significant risk factors for reoperation; however, the preoperative severity of foraminal stenosis had an odds ratio of 7.556 (p = 0.064). SPSD for DLSS showed favorable clinical and radiological outcomes at the mid-term follow-up. SPSD could be a good surgical option for treating DLSS.

Restoration of the Spinous Process Following Muscle-Preserving Posterior Lumbar Decompression via Sagittal Splitting of the Spinous Process.

BackgroundIn lumbar spinal stenosis, spinous process-splitting decompression has demonstrated good clinical outcomes with preservation of the posterior ligamentous complex and paraspinal muscles in comparison to conventional laminectomy, but the radiological consequence and clinical impact of the split spinous processes have not been fully understood.MethodsSeventy-three patients who underwent spinous process-splitting decompression were included. The bone union rate and pattern were evaluated by computed tomography performed 6–18 months after surgery and compared among subgroups divided according to the number of levels decompressed and the extent of spinous process splitting. The bone union pattern was classified into three categories: complete union, partial union, and nonunion. The visual analog scale (VAS) score, Oswestry disability index (ODI), and walking distance assessed both before and 24–36 months after surgery were compared among subgroups divided according to the union pattern of the split spinous process.ResultsOverall, the rates of complete union, partial union, and nonunion were 51.7%, 43.2%, and 5.1%, respectively. In the subgroup with partial splitting of the spinous process, the rates were 85.7%, 14.3%, and 0%, respectively; those of the subgroup with total splitting of the spinous process were 32.9%, 59.2%, and 7.9%, respectively. With single-level decompression, a higher rate of union was observed compared with multilevel decompression. The VAS, ODI, and walking distance were significantly improved after surgery and did not differ according to the degree of union of the split spinous process.ConclusionsWe found that the single-level operation and partial splitting of the spinous process were favourable factors for obtaining complete restoration of the posterior bony structure of the lumbar spine in spinous process-splitting decompression.

A New Fixation Technique for French-Door Cervical Laminoplasty: Surgical Results With a Minimum Follow-up of 6 Years.

A case series of 5 patients with multilevel cervical myelopathy treated by French-door cervical laminoplasty (FDCL) and use of unicortical iliac crest graft as spacer fixed with titanium miniplates and screws is described. To report a minimum of 6-year follow-up results of our new plate-screw fixation technique for FDCL. Hardware-assisted laminoplasty has the potential advantage of preventing restenosis by holding the laminar door "open" while healing progresses and also prevents spacer dislodgement. The use of titanium miniplates as internal fixation device for FDCL by our novel technique has not been reported. Five patients suffering from multilevel cervical myelopathy harboring constitutionally narrow cervical canal (3) and multilevel cervical spondylotic myelopathy (2) who underwent 2-3 level FDCL and followed up prospectively for 6 years is presented. Modified Kurokawa and colleague's technique of FDCL was performed and autologous iliac crest bone graft was interposed between the sagittaly split spinous processes. A 12- to 15-hole titanium miniplate was contoured into a trapezoidal shape to sit flush with the posterior elements. The plate was anchored to bone graft and posterior elements with screws and patients mobilized without any external orthosis. The mean follow-up was 90.5 months. The mean improvement in Neck disability index at final follow-up was 35% and mean improvement in Visual analog scale was 4 points. Japanese orthopaedic association score improved from a mean of 10 to a mean of 14.8 postoperatively. The final outcome was good (3) and excellent (2) by Odom's criteria. All patients improved to Nurick's grade 0 or I and reported significant relief from their myelopathic symptoms and axial neck pain. There were no postoperative hardware-related complications or pseudoarthrosis. Titanium miniplates are excellent devices for stabilizing the interspinous spacers used in FDCL. They prevent cervical canal deformation, restenosis, spacer dislodgement and are durable, cost-effective in facilitating early mobilization at intermediate-term follow-up of 6 years.

Long-Term Outcome of Patients Undergoing Microscopic Lumbar Spinous Process-Splitting Laminectomy

Microscopic lumbar spinous process–splitting laminectomy (LSPSL) has been previously reported as the least invasive surgery for patients with lumbar spinal canal stenosis (LSS). An 18-mm diameter tubular retractor was inserted between the split spinous processes and complete microscopic laminectomy performed in single-level decompressions. A cervical retractor was used to open the caudal parts of the individual halves of the spinous process through a single incision in multi-level decompressions. In this study, we examined long-term outcomes of patients undergoing microscopic LSPSL. Overall, 119 patients with a follow-up longer than 24 months were included in the study. All patients were divided into two groups: 1) the slip group, which included patients with spondylolisthesis-type LSS, and 2) the nonslip group, which included patients with spondylosis-type LSS. The clinical outcomes were evaluated using the Japanese Orthopedic Association score and improvement rate. The slip and instability rates were measured using radiographic imaging findings of the sagittal plane in patients in the slip group. Computed tomography was used to assess bony union of the split spinous process. Magnetic resonance imaging was used to evaluate signal changes of the multifidus muscle at different levels of LSPSL decompression. After LSPSL, pre-operative symptoms were improved with a significant difference in the Japanese Orthopedic Association score. The overall improvement rate was 62.2%; however, it was 48.6% in patients older than 79 years. No significant difference was seen in the slip or instability rate before and after LSPSL. The bony union rate of the split spinous process at the site between the process and the vertebral arch was 79.5%. Post-operative magnetic resonance imaging findings demonstrated a slight amount of fat infiltration in the multifidus muscles after LSPSL. In conclusion, the long-term outcome of patients undergoing LSPSL is satisfactory for a minimally invasive decompression surgery.

Impact of Spinous Process Integrity on Ten to Twelve-Year Outcomes After Posterior Decompression for Lumbar Spinal Stenosis: Study of Open-Door Laminoplasty Using a Spinous Process-Splitting Approach.

In posterior decompression for lumbar spinal stenosis, preservation of the posterior elements appears to provide patients with long-term favorable outcomes. To confirm this assumption, we evaluated the impact of spinous process integrity, i.e., osseous continuity between the spinous process and the lamina, on short to long-term outcomes. As a model for the study of spinous process integrity, we retrospectively reviewed the cases of forty-eight patients who underwent open-door laminoplasty using a spinous process-splitting approach without disrupting attachment sites of the multifidus muscle. In those patients, thirty-nine of the 103 spinous processes achieved spontaneous osseous union with the laminar flap, while the others did not achieve osseous union. The association between the number of ununited spinous processes, as well as baseline characteristics, and the outcomes were analyzed by primary and fully adjusted multivariate linear regression. Outcome measures were the Oswestry Disability Index (ODI) and a numeric rating scale (NRS) for symptoms at two, four, and ten to twelve years. The number of ununited spinous processes was significantly associated with ten to twelve-year scores for the ODI (β = 0.24, p = 0.030), low back pain NRS (β = 0.32, p = 0.030), and leg pain NRS (β = 0.50, p = 0.0012) in the fully adjusted models, but was not associated with two or four-year scores for each scale. The number of decompression levels was significantly associated with ten to twelve-year scores for low back pain and leg pain NRS in the primary models, but was not retained in the fully adjusted models. Osseous continuity between the spinous processes and the lamina after posterior decompression of the lumbar spine is important for maintaining the positive surgical benefit. Deleterious effects of osseous discontinuity on the outcomes were obvious at ten to twelve years, but not at two or four years.

Effectiveness of posterior decompression techniques compared with conventional laminectomy for lumbar stenosis.

To compare the effectiveness of techniques of posterior decompression that limit the extent of bony decompression or to avoid removal of posterior midline structures of the lumbar spine versus conventional facet-preserving laminectomy for the treatment of patients with degenerative lumbar stenosis. A comprehensive electronic search of the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Web of Science, and the clinical trials registries ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform was conducted for relevant literature up to June 2014. A total of four high-quality RCTs and six low-quality RCTs met the search criteria of this review. These studies included a total of 733 participants. Three different techniques that avoid removal of posterior midline structures are compared to conventional laminectomy; unilateral laminotomy for bilateral decompression, bilateral laminotomy and split-spinous process laminotomy. Evidence of low or very low quality suggests that different techniques of posterior decompression and conventional laminectomy have similar effects on functional disability and leg pain. Only perceived recovery at final follow-up was better in patients that underwent bilateral laminotomy compared with conventional laminectomy. Unilateral laminotomy for bilateral decompression and bilateral laminotomy resulted in numerically fewer cases of iatrogenic instability, although in both cases, the incidence of instability was low. The difference in severity of postoperative low back pain following bilateral laminotomy and split-spinous process laminotomy was significantly less, but was too small to be clinically important. We found no evidence to show that the incidence of complications, length of the procedure, length of hospital stay and postoperative walking distance differed between techniques of posterior decompression. The evidence provided by this systematic review for the effects of unilateral laminotomy for bilateral decompression, bilateral laminotomy and split-spinous process laminotomy compared with conventional laminectomy on functional disability, perceived recovery and leg pain is of low or very low quality. Therefore, further research is necessary to establish whether these techniques provide a safe and effective alternative for conventional laminectomy. Proposed advantages of these techniques regarding the incidence of iatrogenic instability and postoperative back pain are plausible, but definitive conclusions are limited by poor methodology and poor reporting of outcome measures among included studies.

The Role of Minimal Invasive Split Laminotomy, the Alternative Parasplit Approach and the “Arch bone” Technique in Surgical Removal of Axial Longitudinal Pathologies in the Spinal Canal

Introduction Conventional approaches to open the spinal canal carries the risk of spinal deformities, instability, subluxation, and invariably separate the muscle attachments from the spinous processes and laminae. Damage to these muscles and bony connections can lead to persistent axial pain and cervical malalignment. With the aim of preserving and reconstructing the posterior structures, the authors developed a novel minimal invasive multilevel spinous process splitting and distraction laminotomy approach, the “arch bone” and the additional rescue parasplit technique. Patients and Methods These novel techniques were used in 70 adult patients with mainly midline located intramedullary pathologies of the cervical, thoracic, and thoracolumbar spine. All muscle attachments on the spinous processes and laminas, as well as the laminas themselves, were completely preserved. With the aim of moderate enlargement of the spinal canal, a spacer was placed between the bony parts facing each other in case of total resection of an intramedullary tumor was not possible. When midline splitting is not feasible or convenient because of anatomical differences of the spinous processes and laminas, we used the parasplit approach. The patients were followed with regular MRI, CT scans, fluoroscopy, and neurological examinations. Results The midline opening of the spinal canal gave a key-hole approach, achieving an adequate view of the intraspinal space for surgery in its entire longitudinal extension. The approach used did not affect the extent of resection proved by MRI evaluation or neurological outcome. The numbers of splitted laminae were 3 to 10. The incidence of postoperative local pain was lower, within acceptable limits (VAS: 2–4). The average length of hospital stay was 6.7 days. Average follow-up was 58 months. Instability and deformity was detected in none of the patients on the flexion–extension lateral radiographs during the follow-up period. Conclusion These surgical approaches suitable for exploring and removing different intramedullary pathologies, help in preventing damage to crucial posterior stabilizers of the spine. Its major advantage is that unnecessary exposure and tissue trauma is reduced, and structures not directly involved in the pathologic process are preserved. In contrast to conventional spinal canal approaches, leaves the muscle attachments intact, disintegration of vertebral arches and facet joints is reduced. Furthermore, these techniques are suitable methods for all spinal segments in all age group. Although the clinical and radiological results are very promising, the limited follow-up period precludes conclusions regarding the long-term results of the procedure, especially with respect to kyphotic deformity.

Effectiveness of posterior decompression techniques compared with conventional laminectomy for lumbar stenosis.

The gold standard treatment for symptomatic lumbar stenosis refractory to conservative management is a facet-preserving laminectomy. New techniques of posterior decompression have been developed to preserve spinal integrity and to minimise tissue damage by limiting bony decompression and avoiding removal of the midline structures (i.e. spinous process, vertebral arch and interspinous and supraspinous ligaments). To compare the effectiveness of techniques of posterior decompression that limit the extent of bony decompression or avoid removal of posterior midline structures of the lumbar spine versus conventional facet-preserving laminectomy for the treatment of patients with degenerative lumbar stenosis. An experienced librarian conducted a comprehensive electronic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science, and the clinical trials registries ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) for relevant literature up to June 2014. We included prospective controlled studies comparing conventional facet-preserving laminectomy versus a posterior decompressive technique that avoids removal of posterior midline structures or a technique involving only partial resection of the vertebral arch. We excluded studies describing techniques of decompression by means of interspinous process devices or concomitant (instrumented) fusion procedures. Participants included individuals with symptomatic degenerative lumbar stenosis only. Two review authors independently assessed risk of bias using the Cochrane Back Review Group criteria for randomised controlled trials (RCTs) and the Newcastle-Ottawa Scale for non-randomised studies. We extracted data regarding demographics, intervention details and outcome measures. A total of four high-quality RCTs and six low-quality RCTs met the search criteria of this review. These studies included a total of 733 participants. Investigators compared three different posterior decompression techniques versus conventional laminectomy. Three studies (173 participants) compared unilateral laminotomy for bilateral decompression versus conventional laminectomy. Four studies (382 participants) compared bilateral laminotomy versus conventional laminectomy (one study included three treatment groups and compared unilateral and bilateral laminotomy vs conventional laminectomy). Finally, four studies (218 participants) compared a split-spinous process laminotomy versus conventional laminectomy.Evidence of low or very low quality suggests that different techniques of posterior decompression and conventional laminectomy have similar effects on functional disability and leg pain. Only perceived recovery at final follow-up was better in people who underwent bilateral laminotomy compared with conventional laminectomy (two RCTs, 223 participants, odds ratio 5.69, 95% confidence interval (CI) 2.55 to 12.71).Among the secondary outcome measures, unilateral laminotomy for bilateral decompression and bilateral laminotomy resulted in numerically fewer cases of iatrogenic instability, although in both cases, the incidence of instability was low (three RCTs, 166 participants, odds ratio 0.28, 95% CI 0.07 to 1.15; three RCTs, 294 participants, odds ratio 0.10, 95% CI 0.02 to 0.55, respectively). The difference in severity of postoperative low back pain following bilateral laminotomy (two RCTs, 223 participants, mean difference -0.51, 95% CI -0.80 to -0.23) and split-spinous process laminotomy compared with conventional laminectomy (two RCTs, 97 participants, mean difference -1.07, 95% CI -2.15 to -0.00) was significantly less, but was too small to be clinically important. A quantitative comparison between unilateral laminotomy and conventional laminectomy was not possible because of different reporting of outcome measures. We found no evidence to show that the incidence of complications, length of the procedure, length of hospital stay and postoperative walking distance differed between techniques of posterior decompression. The evidence provided by this systematic review for the effects of unilateral laminotomy for bilateral decompression, bilateral laminotomy and split-spinous process laminotomy compared with conventional laminectomy on functional disability, perceived recovery and leg pain is of low or very low quality. Therefore, further research is necessary to establish whether these techniques provide a safe and effective alternative for conventional laminectomy. Proposed advantages of these techniques regarding the incidence of iatrogenic instability and postoperative back pain are plausible, but definitive conclusions are limited by poor methodology and poor reporting of outcome measures among included studies. Future research is necessary to establish the incidence of iatrogenic instability using standardised definitions of radiological and clinical instability at comparable follow-up intervals. Long-term results with these techniques are currently lacking.

Cervical Laminoplasty: The History and the Future.

Cervical laminoplasty was developed as an alternative to cervical laminectomy for treatment of cervical myelopathy, in which hinges are created to lift the lamina. Various techniques of laminoplasty have since been developed after two prototype techniques: Hirabayashi’s open-door laminoplasty and Kurokawa’s spinous process splitting (double-door) laminoplasty. Several in vitro studies report superior biomechanical stability of the cervical spine after laminoplasty compared with laminectomy. In clinical situation, randomized control studies are scarce and superiority of one procedure over another is not uniformly shown. Lack of hard evidence supporting the purported advantages of laminoplasty over laminectomy, that is, reduced rate of postoperative instability and kyphosis development, while preserving range of motion (ROM), has been a weak selling point. Currently, laminoplasty is performed by majority of spine surgeons in Japan, but is rarely performed in the United States and Europe. Recent development in laminoplasty is preservation of muscle attachment, which enabled dynamic stabilization of the cervical spine by neck extensor muscles. After treatment with new laminoplasty techniques with active postoperative neck ROM exercises, postoperative instability, kyphosis, axial neck pain, and loss of ROM seems minimal. Well-designed clinical trials to show the effectiveness and long-term outcome of this surgical procedure are warranted.

Modified Marmot Operation Versus Spinous Process Transverse Cutting Laminectomy for Lumbar Spinal Stenosis

Retrospective comparative cohort study. To compare clinical outcomes for lumbar spinal stenosis (≥3 levels) treated with posterior decompression without exposing the paravertebral muscles (PVM) with outcomes from surgery with PVM exposure. Exposure of the PVM can cause muscle injury and denervation, which may induce failed back syndrome. However, it is unknown whether lumbar spinal stenosis is more likely to lead to clinical improvement after PVM preservation than the procedure involving exposure of the PVM. Fifty-three patients with lumbar spinal stenosis were divided on the basis of the timing of the surgery into 2 groups: modified split-spinous process laminotomy (Marmot operation) (MM) group (26 patients) and spinous process transverse cutting laminectomy through a unilateral approach (control) group (27 patients). The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, visual analogue scale score of low back pain, and patients' satisfaction were assessed preoperatively and 1 year postoperatively. Operation time, blood loss, and creatine phosphokinase and C-reactive protein levels were measured 7 days postoperatively. Magnetic resonance imaging changes in the PVM were evaluated at the follow-up. The preoperative visual analogue scale and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire scores did not differ between groups. The operation time did not differ between groups, but blood loss was less in the MM group than in the control group (129 vs. 205 mL) (P < 0.05). C-reactive protein (1.1 vs. 2.8 mg/dL) and creatine phosphokinase (68 vs. 253 IU/L) levels were lower in the MM group (P < 0.05). The visual analogue scale score for low back pain and patient satisfaction did not differ between groups. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire scores for pain-related disorders, gait disturbance, and social life disturbance improved significantly in the MM group compared with the control group (P < 0.05). Nine patients in the control group showed positive changes in the PVM. The MM operation was less invasive and produced superior clinical outcomes compared with laminectomy involving exposure of the PVM.

Para-Split Laminotomy: A Rescue Technique for Split Laminotomy Approach in Exploring Intramedullary Midline Located Pathologies

Conventional posterior approaches, which may involve multilevel laminectomies and facetectomies, may lead to spinal deformities, instability, and subluxation. We developed the multilevel spinous process splitting and distraction laminotomy technique, which is an option for approaching midline intramedullary spinal pathologies with preservation of mechanically relevant bone and muscle structures. In some cases, midline splitting is not feasible or convenient because of anatomical differences of spinous processes and laminas. Our objective was to develop a minimally invasive rescue approach technique that makes it possible to remove intramedullary lesions but does not increase the risk of damage to the crucial posterior stabilizers of the spine. We used the para-split laminotomy technique for opening the spinal canal not in the midline but rather in the parasagittal plane. The technique can be combined with the basic split laminotomy technique. This novel technique was used in five adult patients with midline intramedullary pathologies of the cervical and cervicothoracic spine. The operating field under the microscope was sufficient for tumor removal according to the keyhole concept. The approach used did not affect the extent of resection or neurologic outcome. The average number of split laminae was 6 (range: 3-10). Average follow-up was 18 months (range: 13-36 months). Histologic results were as follows: two ependymomas, two astrocytomas, and one primitive neuroectodermal tumor (PNET). To confirm the extension of resection, all patients underwent postoperative magnetic resonance imaging evaluations. The resections were complete in the cases of two ependymomas, subtotal in one astrocytoma, and partial in the other astrocytoma case and the PNET case. Computed tomography scans showed the extension of para-split approaches and the moderately disturbed bony structures. Instability was detected in none of the patients on the flexion-extension lateral radiographs during the follow-up period. The minimally invasive multilevel para-split laminotomy approach as a rescue technique for split laminotomy is a safe and effective surgical procedure, suitable for exploring different intramedullary pathologies located in the midline of the spinal canal. This modified surgical approach fulfills the requirements of other minimally invasive techniques and lowers the risk of damage to the crucial posterior stabilizers of the spine; furthermore, disintegration of the vertebral arches and facet joints is reduced.

A chronic flexion-distraction injury with a “fistulous wither” on the split spinous process of the L1 vertebra—a case report of a modified transpedicle wedge osteotomy

Flexion-distraction injuries (FDIs) are caused by high-energy force and momentum on the spine. In general, the posterior column and the posterior wall of the affected vertebra have failed in distraction, and the anterior column has failed in compression based on Denis’ three column theory [1]. Hoshikawa et al. has proposed a motion axis of FDIs, which is defined as a transitional line from the anterior compression to the posterior splitting failure [2]. In terms of biomechanics, the integrity of the posterior tension band of the affected vertebrae has failed in FDIs. As a result of this loss of integrity of the posterior element, kyphotic deformity easily develops and remains unless proper treatment has been optioned in FDIs. Fresh FDIs with minimal displacement are usually treated with an extension brace or body cast, and they have a good prognosis. Meanwhile, treatment of chronic FDIs is complicated. Backache and/or gibbus, which is caused by rigid kyphosis even after bone fusion at the affected segment, is a major residual symptom in chronic FDIs. Nonoperative treatment can rarely cure rigid kyphotic deformity. Malcom et al. stated that persistent back pain in the lumbar spine and the buttocks is usually related to a compensatory hyperlordosis below the kyphotic segment [3]. Although the degree to which kyphosis should be corrected operatively is still controversial, surgical intervention is indicated for some cases with backache and/or ill cosmesis caused by rigid kyphotic deformity in chronic FDIs. LeGay et al. have proposed that a deformity of greater than 17° in kyphosis of FDIs shows a clinically poor result and an instability in vivo [4]. For surgical treatment of a rigid kyphotic deformity of chronic FDIs, access to the damaged vertebra, releasing the scar tissue, correction of the kyphosis and a stable support in the anterior and middle columns are crucial. In the anterior approach, a wide surgical field of the affected segment is obtained, but it is associated with significant pulmonary and incisional morbidity. Conversely, the posterior approach provides more limited access with less morbidity, and it also enables surgeons to directly observe the neural tissue after resection of the damaged posterior elements in FDIs. A supraspinous bursitis is described as “fistulous withers” in horses [5]. It is a mechanical inflammation caused by a poorly fitting tack on horse withers. It begins as a painless encapsulated accumulation of serum associated with the supraspinous bursa. To my best knowledge in English and Japanese literature, there is no report of a symptomatic bursitis on the lumbar spinous process in humans. The supraspinous and the interspinous ligaments are less resilient to stress than the interval disc and the capsular ligament. Thus, there is a possibility that a condition similar to “fistulous withers” in horses develops in humans, when a local post-traumatic kyphosis of chronic FDIs remains in the human thoracolumbar spine. The purpose of the current article is a case report of chronic FDIs in the L1 vertebra. The patient had developed a rigid kyphosis associated with a bursitis on the distracted spinous process. He underwent radical excision of the affected soft tissue, partial resection of the fractured spinous process, a modified transpedicle wedge osteotomy in a fractured line, and augmented with pedicle screws and titanium interbody cages. An excellent prognosis has been obtained in the current case.

The meanings of reposition and fixation of split spinous processes in lumbar spinous process-splitting laminectomy

The meanings of reposition and fixation of split spinous processes in lumbar spinous process-splitting laminectomy

Spinous process-splitting open pedicle screw fusion provides favorable results in patients with low back discomfort and pain compared to conventional open pedicle screw fixation over 1 year after surgery

The conventional open pedicle screw fusion (PSF) requires an extensive detachment of the paraspinal muscle from the posterior aspect of the lumbar spine, which can cause muscle injury and subsequently lead to "approach-related morbidity". The spinous process-splitting (SPS) approach for decompression, unilateral laminotomy for bilateral decompression, and the Wiltse approach for pedicle screw insertion are considered to be less invasive to the paraspinal musculature. We investigated whether SPS open PSF combined with the abovementioned techniques attenuates the paraspinal muscle damage and yields favorable clinical results, including alleviation in the low back discomfort, in comparison to the conventional open PSF. We studied 53 patients who underwent single-level PSF for the treatment of degenerative spondylolisthesis (27 patients underwent SPS open PSF and the other 26 underwent the conventional open PSF). The clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score, the Roland-Morris disability questionnaire (RDQ), and the visual analog scale (VAS) for low back pain and low back discomfort (heavy feeling or stiffness). Postoperative multifidus (MF) atrophy was evaluated using MRI. Follow-up examinations were performed at 1 and 3years after the surgery. Although there was no significant difference in the JOA and RDQ score between the two groups, the VAS score for low back pain and discomfort after the surgery were significantly lower in the SPS open PSF group than in the conventional open PSF group. The extent of MF atrophy after SPS open PSF was reduced more significantly than after the conventional open PSF during the follow-up. The MF atrophy ratio was found to correlate with low back discomfort at the 1-year follow-up examination. In conclusion, SPS open PSF was less damaging to the paraspinal muscle than the conventional open PSF and had a significant clinical effect, reducing low back discomfort over 1year after the surgery.

Union and Laminar Bone Growth around Hydroxyapatite Spacers with Split Spinous Process in Double-Door Laminoplasty for Multilevel Cervical Spondylotic Myelopathy and Ossification of Posterior Longitudinal Ligament

Union and Laminar Bone Growth around Hydroxyapatite Spacers with Split Spinous Process in Double-Door Laminoplasty for Multilevel Cervical Spondylotic Myelopathy and Ossification of Posterior Longitudinal Ligament

Minimal invasive surgical techniques for the treatment of pathologic lesions, situated in the midline of the spinal canal

Objective: Multilevel laminectomy for exposing the spinal canal to remove spinal cord lesions has been widely used in spine surgery. Destruction of the dorsal structures of the spinal column, detachment of the longitudinal musculature, resection of the vertebral arches, and injury of the joint capsules and ligaments are responsible most of short and late-time complications. Spinal deformities, instability, subluxation, invasion of haematoma and scar tissue into the spinal canal are the most often mentioned complications in the literature. The author main objective was to develop and summarize the novel minimally invasive techniques suitable for exploring and treating different pathologies, located in the midline of the spinal canal with preservation of the stability of the spine. Methods: 38 patients were operated on with intramedullary laesions located from CIII to LI level of the spine with the newly developed multilevel spinous process splitting and distracting laminotomy technique. The dorsal, paraspinal musculature was not detached from the vertebras. With splitting and distracting the spinous processes and the vertebral arches, the vertebral joints, the joint capsules and the ligaments were not injured, these structures remained mostly intact. To achieve a moderate enlargement and decompression of the spinal canal, complementary intervertebral spacer insertion was performed in some cases. The patients were followed with regular MRI, CT scans and neurological examinations. Results: Adequate surgery of the lesions located intramedullary was achieved in all patients using our new procedures. Moderate enlargement and permanent decompression of the spinal canal was achieved with the insertion of homologues tricortical iliac crest bone graft or heterologous PEEK spacer. The numbers of split laminae were 3 to 6. The split spinous processes were closed directly to each other in 24 patients. In 9 cases a tricortical bone graft and in 5 cases a heterologous PEEK spacer was inserted between the facing bony parts. The incidence of postoperative local pain was lower, within acceptable limits, and early mobilization was allowed. The average length of hospital stay was shorter too. The postoperative followup CT scans demonstrated bony healing, with the inserted graft or cage between the osteotomized faces. No compression or dislocation of the spacer was seen. Instability was not detected in any of the patients by fl exion or extension lateral radiographs. DOI: 10.17489/biohun/2010/1/23

Spinous process splitting and reposition laminotomy for lumbar spinal stenosis: clinical results and union of split spinous process

Spinous process splitting and reposition laminotomy for lumbar spinal stenosis: clinical results and union of split spinous process

Dural Laceration

The authors describe 4 cases of delayed dural laceration by hydroxyapatite (HA) spacer causing tetraparesis following double-door laminoplasty. There are few reports of iatrogenic spinal cord lesions developing after double-door laminoplasty, although some complications such as postoperative C-5 paralysis or axial symptoms have been reported. The purpose of this report is to draw attention to the possibility of delayed dural laceration and its triggering mechanism. One hundred thirty patients treated for cervical myelopathy were followed up for an average of 2 years and 9 months after laminoplasty. Four patients experienced aggravation of cervical myelopathy. Anterior dislodgement of HA spacers was shown on plain lateral radiographs. Follow-up T2-weighted magnetic resonance imaging demonstrated that the dislodged HA spacers were surrounded by cerebrospinal fluid at the time of aggravation. The dislodged HA spacers were removed and the dural membrane defects were repaired by patching with the fascia of the gluteus maximus muscle. The preoperative symptoms improved after the second operation in all patients. It is hypothesized that the loosening of the HA spacer in split spinous processes could occur with the movement of the cervical spine and/or the breakage of the suture before bone bonding. Anterior dislodgement of the HA spacer toward the spinal canal would cause dural laceration by direct friction between the dural membrane and the dislodged HA spacer, resulting in clinical aggravation. Despite the well-documented advantages of using HA spacers for double-door laminoplasty, possible laceration due to a dislodged HA spacer should be considered as a late complication.