Spinous process splitting laminectomy for lumbar canal stenosis: a critical appraisal

Spinous process splitting laminectomy (SPSL) is a surgical technique for lumbar canal stenosis, which aims to preserve the paraspinal muscles. Twenty-five patients with lumbar canal stenosis who consecutively underwent SPSL from June 2005 to December 2005 were evaluated. Clinical outcomes were assessed using the visual analogue scale (VAS) scores and Oswestry disability index (ODI). Mean age of the patients at surgery was 62.6 years (range: 42-77 years). Seventeen patients underwent SPSL for single level stenosis, 4 for two levels, and 4 for three levels. In 10 patients, discectomy was simultaneously performed at the same level as SPSL. Of 23 patients (92%) followed for a 1-year period, VAS for back pain, leg pain, and ODI decreased significantly; from 4.8, 8.1, and 54.3-2.1, 2.7, and 23.1, respectively. However, a significant improvement (> 50% of their initial VAS/ODI score) of back pain, leg pain, and functional status was observed in only 65.2, 65.2, and 52.2%, respectively. Complications occurred in 4 patients (16%). Although SPSL for lumbar canal stenosis yielded relatively good clinical outcomes, the percentage of patients showing significant improvements in back pain, leg pain, and functional status were less than expected at one year after surgery.     

Torsion biomechanics of the spine following lumbar laminectomy: a human cadaver study

Purpose

Lumbar laminectomy affects spinal stability in shear loading. However, the effects of laminectomy on torsion biomechanics are unknown. The purpose of this study was to investigate the effect of laminectomy on torsion stiffness and torsion strength of lumbar spinal segments following laminectomy and whether these biomechanical parameters are affected by disc degeneration and bone mineral density (BMD).

Methods

Ten human cadaveric lumbar spines were obtained (age 75.5, range 59–88). Disc degeneration (MRI) and BMD (DXA) were assessed. Disc degeneration was classified according to Pfirrmann and dichotomized in mild or severe. BMD was defined as high BMD (≥median BMD) or low BMD (<median BMD). Laminectomy was performed either on L2 (5×) or L4 (5×). Twenty motion segments (L2–L3 and L4–L5) were isolated. The effects of laminectomy, disc degeneration and BMD on torsion stiffness (TS) and torsion moments to failure (TMF) were studied.

Results

Load–displacement curves showed a typical bi-phasic pattern with an early torsion stiffness (ETS), late torsion stiffness (LTS) and a TMF. Following laminectomy, ETS decreased 34.1 % (p < 0.001), LTS decreased 30.1 % (p = 0.027) and TMF decreased 17.6 % (p = 0.041). Disc degeneration (p < 0.001) and its interaction with laminectomy (p < 0.031) did significantly affect ETS. In the mildly degenerated group, ETS decreased 19.7 % from 7.6 Nm/degree (6.4–8.4) to 6.1 Nm/degree (1.5–10.3) following laminectomy. In the severely degenerated group, ETS decreased 22.3 % from 12.1 Nm/degree (4.6–21.9) to 9.4 Nm/degree (5.6–14.3) following laminectomy. In segments with low BMD, TMF was 40.7 % (p < 0.001) lower than segments with high BMD [34.9 Nm (range 23.7–51.2) versus 58.9 Nm (range 43.8–79.2)].

Conclusions

Laminectomy affects both torsion stiffness and torsion load to failure. In addition, torsional strength is strongly affected by BMD whereas disc degeneration affects torsional stiffness. Assessment of disc degeneration and BMD pre-operatively improves the understanding of the biomechanical effects of a lumbar laminectomy.     

Magnetic resonance imaging evaluation of thecal sac diameters following laminectomy in the lumbar spine

Sagittal magnetic resonance images (MRIs) from 20 patients who had postoperative persistent or recurrent low back pain were reviewed to study the thecal sac diameter at laminectomy sites. The thecal sac anteroposterior diameter was measured in three sites: the maximum AP diameter at the laminectomy site, and the proximal and distal levels to the laminectomy site. A comparison between the thecal sac AP diameter at laminectomy sites and the average diameter of both the proximal and distal levels was then made. Based on the measurements, the diameters of the thecal sac were divided into three groups. Patients in group A (5 cases) had a constriction (the thecal sac AP diameter at the laminectomy site was less than the average diameter of both the proximal and distal levels) of the thecal sac at the laminectomy site. Patients in group B (12 cases) had an expansion (the thecal sac AP diameter at the laminectomy site was more than the average diameter of both the proximal and distal levels) of the thecal sac. Patients in group C (3 cases) demonstrated no change. This study suggests that there was no correlation between the thecal sac AP diameter at laminectomy site and postoperative low back pain.     

腰椎关节突关节骨性关节炎对腰椎稳定性的影响

目的探讨腰椎退变过程中,腰椎间盘退变、关节突关节骨性关节炎与腰椎稳定性之间的关系.方法对78名腰椎退变患者进行腰椎MRI和动力位X线摄影.腰椎不稳分为椎间角度运动不稳、旋转不稳和椎间位移不稳,其中椎间位移不稳细分为前向不稳、后向不稳和前后向不稳.腰椎间盘退变依据矢状位T2加权像分为5级;关节突关节骨性关节炎依据水平位T1加权像分为4级.对资料进行统计分析.结果腰椎椎间角度运动不稳和前后向椎间位移不稳与关节突关节骨性关节炎存在显著负相关,前向椎间位移不稳与腰椎关节突关节骨性关节炎和椎间盘退变呈显著正相关,腰椎矢状面旋转不稳与腰椎关节突关节骨性关节炎无显著相关.结论腰椎间盘退变和腰椎关节突关节骨性关节炎可影响腰椎运动节段的稳定性.     

Neurologic complications and lumbar laminectomy. A standardized approach to the multiply-operated lumbar spine.

Even the careful and knowledgeable spine surgeon will encounter a variety of neurologic complications during and after routine lumbar laminectomy. These include dural and nerve root injuries; cauda equina syndrome; and formation of scar tissue, extradural and intradural (arachnoiditis). The surgeon must be prepared to identify each of these problems and deal with them effectively at the time of the procedure and in the immediate postoperative and follow-up periods. The physician evaluating the multiply-operated lumbar spine patient must use an organized approach. The origin of the problem in most instances is a faulty decision to perform the original operative procedure. Further surgery on an "exploratory" basis is not warranted in any situation and most likely will lead only to further disability. There should be definite objective findings to substantiate the patient's symptoms. The etiology of each patient's symptoms. must be accurately localized and identified. Medical status and psychosocial situation--as well as orthopedic and neurologic findings--should be evaluated at the time of the initial consultation. Once the spine is identified as the probable source of symptoms, specific features should be sought in the patient's clinical history, physical examination, and roentgenographic studies. The number of previous operations, length of pain-free interval, and predominance of leg versus back pain are the major historic signposts. The presence of a tension sign and the neurologic findings are the focal points of the physical examination. Plain roentgenograms, motion films, water-soluble myelogram, computed axial tomography, and magnetic resonance imaging with contrast have specific roles in the workup.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spinaplasty following lumbar laminectomy for multilevel lumbar spinal stenosis to prevent iatrogenic instability

Background:

Iatrogenic instability following laminectomy occurs in patients with degenerative lumbar canal stenosis. Long segment fusions to obviate postoperative instability result in loss of motion of lumbar spine and predisposes to adjacent level degeneration. The best alternative would be an adequate decompressive laminectomy with a nonfusion technique of preserving the posterior ligament complex integrity. We report a retrospective analysis of multilevel lumbar canal stenosis that were operated for posterior decompression and underwent spinaplasty to preserve posterior ligament complex integrity for outcome of decompression and iatrogenic instability.

Materials and Methods:

610 patients of degenerative lumbar canal stenosis (n=520) and development spinal canal stenosis (n=90), with a mean age 58 years (33–85 years), underwent multilevel laminectomies and spinaplasty procedure. At followup, changes in the posture while walking, increase in the walking distance, improvement in the dysesthesia in lower limb, the motor power, capability to negotiate stairs and sphincter function were assessed. Forward excursion of vertebrae more than 4 mm in flexion–extension lateral X-ray of the spine as compared to the preoperative movements was considered as the iatrogenic instability. Clinical assessment was done in standing posture regarding active flexion–extension movement, lateral bending and rotations

Results:

All patients were followed up from 3 to 10 years. None of the patients had neurological deterioration or pain or catch while movement. Walking distance improved by 5–10 times, with marked relief (70–90%) in neurogenic claudication and preoperative stooping posture, with improvement in sensation and motor power. There was no significant difference in the sagittal alignment as well as anterior translation. Two patients with concomitant scoliosis and one with cauda equine syndrome had incomplete recovery. Two patients who developed disc protrusion, underwent a second operation for a symptomatic disc prolapse.

Conclusion:

Spinaplasty following posterior decompression for multilevel lumbar canal stenosis is a simple operation, without any serious complications, retaining median structures, maintaining the tension band and the strength with least disturbance of kinematics, mobility, stability and lordosis of the lumbar spine.     

Long-term evaluation of cervical spine disorders following laminectomy

The Authors report the results obtained by long-term clinical and radiological evaluation of patients who had undergone cervical multiple bilateral laminectomy to relieve the compression exerted on the cord by different diseases (spondylarthrosis, syringohydromyelia, intramedullary and extramedullary tumours, leptomeningeal cysts and extradural tumours). 98 patients were reviewed, the follow-up ranging from 8 to 24 years (mean 14 years). The results demonstrate that the most severe post-laminectomy changes are recorded in patients with intramedullary lesions and when middle-low cervical spine levels (C4-C7) are affected. The significance of spinal deformities such as kyphosis, spondylolisthesis and swan-neck is also discussed.     

Experimental study of osteoplastic laminectomy in the lumbar spine of rabbits

Osteoplastic laminectomy has been used to treat lumbar canal stenosis and to prevent postoperative lumbar spinal instability by reconstructing the posterior element of the lumbar spine, which has been documented in many clinical studies. However, the biological sequence of repairing the posterior lumbar element, which is replaced at the time of surgery, has not yet been made clear. An in vivo rabbit study was designed to observe the biological sequence of repairing the replaced posterior element of the lumbar spine. Twenty-one adult rabbits underwent osteoplastic laminectomy at the L6. Animals were killed at 2, 4, 8, 12, 26, and 52 weeks after surgery. The samples of the L6 vertebra, which contained the replaced lamina and spinous process, were analyzed by radiography, computed tomography (CT), and a histological method. Overall, radiograms demonstrated clearly the union of interarticular osteotomized sites from 4 to 8 weeks. CT findings revealed that the union of interarticular osteotomized sites could be confirmed beginning at 12 weeks, and that postoperative narrowing of the lumbar spinal canal had not occurred in the rabbit model. The biological sequence of repairing the replaced lamina and spinous process was characterized by slowly progressive creeping substitution, with continuous remodeling.     

Biomechanical analysis of the disc adjacent to posterolateral fusion with laminectomy in lumbar spine

OBJECTIVES: After posterolateral fusion with laminectomy for the degenerative lumbar spine, accelerated degeneration of the disc adjacent to the fusion mass has been clinically observed. Previous studies used a finite element model (FEM) to calculate the stress of the adjacent disc in the fused lumbar spine with spinal fixator and bone graft. However, little emphasis was placed on the simultaneous spinal fusion and decompression procedure. To investigate if the spinal decompression procedure in posterolateral fusion would increase stress significantly, the FEM was employed to estimate the stress concentration of the disc above the fusion mass in posterolateral fusion with laminectomy and hemilaminectomy. METHODS: Three FEMs of the lumbar spine were established: intact spine, posterolateral fusion with total laminectomy, and posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments). The posterolateral fusion added spinal fixator and bone graft between the transverse process. The L1 vertebral body was subjected to 10-Nm flexion, extension, torsion, and lateral bending. The bottom of the L5 vertebral body was fixed. RESULTS: In flexion, the stress on the adjacent disc in posterolateral fusion with laminectomy and hemilaminectomy respectively increased 90% and 21% over that of the intact spine. In posterolateral fusion with hemilaminectomy, the supraspinous and interspinous ligaments shared some external forces to alleviate the stress concentration of the adjacent disc. However, in extension, torsion, and lateral bending, these two fusion models had almost no change in range of motion and stress of adjacent disc. CONCLUSION: Posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments) was able to alleviate the stress concentration of the disc above the fusion mass in flexion.     

Analysis of the cervical spine alignment following laminoplasty and laminectomy

Very little detailed biomechanical examination of the alignment of the cervical spine following laminoplasty has been reported. We performed a comparative study regarding the buckling-type alignment that follows laminoplasty and laminectomy to know the mechanical changes in the alignment of the cervical spine. Lateral images of plain roentgenograms of the cervical spine were put into a computer and examined using a program we developed for analysis of the buckling-type alignment. Sixty-four patients who underwent laminoplasty and 37 patients who underwent laminectomy were reviewed retrospectively. The subjects comprised patients with cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal ligament (OPLL). The postoperative observation period was 6 years and 7 months on average after laminectomy, and 5 years and 6 months on average following laminoplasty. Development of the buckling-type alignment was found in 33% of patients following laminectomy and only 6% after laminoplasty. Development of buckling-type alignment following laminoplasty appeared markedly less than following laminectomy in both CSM and OPLL patients. These results favor laminoplasty over laminectomy from the aspect of mechanics.     

全椎板切除对兔脊柱生长发育的影响

本试验切除幼兔和成兔多节段全椎板观察其脊柱畸形情况,实验分为两组,幼兔组(A组):10只,日龄40天,体重460g(400～550g);成兔组(B组):10只,月龄6个月,体重2kg(1.5～2.5kg)。结果表明多节段全椎板切除可造成幼兔比成兔更多更重的畸形,如后凸、侧凸、椎体楔形变、滑脱及广泛的椎管内粘连。     

Autonomic insufficiency as a factor contributing to dialysis-induced hypotension.

BACKGROUND: Autonomic insufficiency is considered a factor that contributes to dialysis-induced hypotension (DIH). However, the relationship between the two conditions has not been fully elucidated. METHODS: We investigated 44 haemodialysis patients using [(123)I]-meta-iodobenzylguanidine (MIBG) scintigraphy and power-spectral analysis (PSA) of heart rate variability. The patients were divided into four groups: a diabetic group with DIH, a diabetic group without DIH, a non-diabetic group with DIH, and a non-diabetic group without DIH. In these groups the heart to mediastinum average count rate (H/M), MIBG washout rate, and low- and high-frequency components of PSA were compared. RESULTS: From the [(123)I]-MIBG scintigraphy, for both early and delayed images, H/M of the groups with DIH were lower than in groups without DIH, in both diabetics and non-diabetics (P<0.05). For the early images, H/M of the diabetic groups were lower than in the non-diabetic groups, in the groups both with and without DIH (P<0.01). For the delayed images, H/M of the diabetic group was lower than in the non-diabetic group, in the groups with DIH (P<0.05). The MIBG washout rate was the highest in the diabetic group with DIH (P<0.05 vs diabetic and non-diabetic groups without DIH). The PSA of heart rate variability showed a good discrimination of the low-frequency component between the non-diabetic patients with and without DIH (P<0.05). Mean ultrafiltration volume and its rate were not different among the four groups. CONCLUSION: Autonomic insufficiency is more severe in patients with DIH than in those without, and its degree may be enhanced in diabetic patients. For the management of DIH, special care should be addressed not only to dry weight but also to autonomic insufficiency.     

Intracranial hemorrhage following lumbar spine surgery

Background

Intracranial hemorrhage is a serious but rare complication of spinal surgery, which can occur in the intracerebral, cerebellar, epidural, or subdural compartment.

Purpose

To describe patients with intracranial hemorrhage after lumbar spinal surgery and present clinical and diagnostic imaging findings.

Methods

In this retrospective study, medical records of 1,077 patients who underwent lumbar spinal surgery in our tertiary referral neurosurgery center between January 2003 and September 2010 were studied. The original presentations of the patients before the surgical intervention were herniated lumbar disc, spinal canal stenosis, spondylolisthesis, lumbar spinal trauma, and lumbar spine and epidural tumor. The operations performed consisted of discectomy, multiple level laminectomy, stabilization and fusion, lumbar instrumentation, and lumbar spinal and epidural tumor resection.

Results

Four cases developed intracranial hemorrhage including acute subdural hematoma (one case), epidural hematoma (one case), and remote cerebellar hemorrhage (two cases). The clinical and diagnostic imaging characteristics along with treatments performed and outcomes of these four patients are described and the pertinent literature regarding post-lumbar spinal surgery intracranial hemorrhages is reviewed.

Conclusion

Though rare, intracranial hemorrhage can occur following lumbar spinal surgery. This complication may be asymptomatic or manifest with intense headache at early stages any time during the first week after surgery. Dural tear, bloody CSF leakage, focal neurologic symptoms, and headache are indicators of potential intracranial hemorrhage, which should be considered during or following surgery and necessitate diagnostic imaging.     

The management of pain following laminectomy for lumbar disc lesions

Assessment of the results of laminectomy for lumbar disc lesions is unsatisfactory, but it seems that some degree of recurrent pain is virtually inevitable. The clinical features and incidence of the various painful syndromes seen in these patients, including one, the sacro-spinalis insertion syndrome, which has not previously been described, are outlined and the management of each is discussed with reference to two personal series, one of 98 patients consecutively undergoing laminectomy and the other of 35 patients referred because of recurrent pain following laminectomy. Finally, problems of prophylaxis are considered.     

Anterior shear strength of the porcine lumbar spine after laminectomy and partial facetectomy

Degenerative lumbar spinal stenosis is the most common reason for lumbar surgery in patients in the age of 65 years and older. The standard surgical management is decompression of the spinal canal by laminectomy and partial facetectomy. The effect of this procedure on the shear strength of the spine has not yet been investigated in vitro. In the present study we determined the ultimate shear force to failure, the displacement and the shear stiffness after performing a laminectomy and a partial facetectomy. Eight lumbar spines of domestic pigs (7 months old) were sectioned to obtain eight L2–L3 and eight L4–L5 motion segments. All segments were loaded with a compression force of 1,600 N. In half of the 16 motion segments a laminectomy and a 50% partial facetectomy were applied. The median ultimate shear force to failure with laminectomy and partial facetectomy was 1,645 N (range 1,066–1,985) which was significantly smaller (p = 0.012) than the ultimate shear force to failure of the control segments (median 2,113, range 1,338–2,659). The median shear stiffness was 197.4 N/mm (range 119.2–216.7) with laminectomy and partial facetectomy which was significantly (p = 0.036) smaller than the stiffness of the control specimens (median 216.5, 188.1–250.2). It was concluded that laminectomy and partial facetectomy resulted in 22% reduction in ultimate shear force to failure and 9% reduction in shear stiffness. Although relatively small, these effects may explain why patients have an increased risk of sustaining shear force related vertebral fractures after spinal decompression surgery.     

The impact of bone mineral density and disc degeneration on shear strength and stiffness of the lumbar spine following laminectomy

Purpose  

Laminectomy is a standard surgical procedure for elderly patients with symptomatic degenerative lumbar stenosis. The procedure aims at decompression of the affected nerves, but it also causes a reduction of spinal shear strength and shear stiffness. The magnitude of this reduction and the influence of bone mineral density (BMD) and disc degeneration are unknown. We studied the influence of laminectomy, BMD, and disc degeneration on shear force to failure (SFF) and shear stiffness (SS).     

In-hospital complication rate following microendoscopic versus open lumbar laminectomy: a propensity score-matched analysis

Background Context

The incidence of postoperative complications after microendoscopic laminectomy (MEL) has not been compared with that after open laminectomy in a large study, so it is not clear whether MEL is a safer procedure.