A retrospective study of computed tomography (CT) myelographic images in patients with degenerative lumbar spinal stenosis (LSS).
To introduce a new technique for the quantitative evaluation of LSS.
Advances in hardware and software technology now permit inexpensive digitalization of radiological images, and enable methodologies for quantifying space available for neural elements in spinal canal. However, a valid method with quantitative evaluation of spinal stenosis in living patients has not been developed yet.
Methods and materials
Preoperative CT myelographic scans of 50 patients with degenerative LSS were collected for retrospective investigation. The patients subsequently underwent lumbar decompressive surgery. They included scans from thoracic vertebra 12 (T12) to sacrum (S1), in which each segment was scanned through both the vertebral body and disk. All CT scan films were digitized using a high-resolution digital camera. ImageTool™ software was used to measure three parameters: cross-sectional area of dural sac at disk level (A), cross-sectional area of spinal canal at midpedicular level (B), and cross-sectional area of vertebral body (C). The dural sac canal ratio (DSCR) was calculated as A/B×100%. Low DSCR implied severe dural sac compression with a high degree of stenosis. The spinal canal vertebral ratio (CVR) was also calculated as B/C×100%. Low CVR implied a low baseline of canal capacity for neural elements. They were calculated from T12 to S1.
The study consisted of 26 male and 24 female patients, with an average age of 68.4 (35–97) years. A total of 295 segments were evaluated, of which 118 (40%) were surgically decompressed. There were wide ranges of canal cross-sectional areas (140–475 mm2) and dural sac cross-sectional area (54–435 mm2). Male patients had a slightly larger canal cross-sectional area than female patients at each level. The mean CVR was found decreased from T12 (26.1%) to L4 (18.3%). This was higher in female than in male patients, especially from T12 to L2 (P < 0.01). There were significant correlations between spinal canal and dural sac cross-sectional area (r = 0.55, P < 0.001), and also between CVR and DSCR (r = 0.31, P < 0.001). Of the levels decompressed, 82% was performed from the level L2 to L5, in which there was no significant difference in canal cross-sectional area and CVR between decompression and nondecompression (P > 0.05). There was a good correspondence between decreasing mean DSCR and increasing percentile of levels decompressed.
DSCR represents a useful method for the quantitative diagnosis of lumbar spinal canal stenosis. ImageTool™ software is a useful tool in measuring spinal morphometry.
lumbar spinal stenosis; quantitative diagnosis; ImageTool™
Background and purpose
MRI is the modality of choice when diagnosing spinal stenosis but it also shows that stenosis is prevalent in asymptomatic subjects over 60. The relationship between preoperative health-related quality of life, functional status, leg and back pain, and the objectively measured dural sac area in single and multilevel stenosis is unknown. We assessed this relationship in a prospective study.
Patients and methods
The cohort included 109 consecutive patients with central spinal stenosis operated on with decompressive laminectomy or laminotomy. Preoperatively, all patients completed the questionnaires for EQ-5D, SF-36, Oswestry disability index (ODI), estimated walking distance and leg and back pain (VAS). The cross-sectional area of the dural sac was measured at relevant disc levels in mm2, and spondylolisthesis was measured in mm. For comparison, the area of the most narrow level, the number of levels with dural sac area < 70 mm2, and spondylolisthesis were studied.
Before surgery, patients with central spinal stenosis had low HRLQoL and functional status, and high pain levels. Patients with multilevel stenosis had better general health (p = 0.04) and less leg and back pain despite having smaller dural sac area than patients with single-level stenosis. There was a poor correlation between walking distance, ODI, the SF-36, EQ-5D, and leg and back pain levels on the one hand and dural sac area on the other. Women more often had multilevel spinal stenosis (p = 0.05) and spondylolisthesis (p < 0.001). Spondylolisthetic patients more often had small dural sac area (p = 0.04) and multilevel stenosis (p = 0.06).
Our findings indicate that HRQoL, function, and pain measured preoperatively correlate with morphological changes on MRI to a limited extent.
We present a rare case of delayed onset of epidural hematoma after lumbar surgery whose only presenting symptom was vesicorectal disturbance. A 68-year-old man with degenerative spinal stenosis underwent lumbar decompression and instrumented posterolateral spine fusion. The day after his discharge following an unremarkable postoperative course, he presented to the emergency room complaining of difficulty in urination. An MRI revealed an epidural fluid collection causing compression of the thecal sac. The fluid was evacuated, revealing a postoperative hematoma. After removal of the hematoma, his symptoms disappeared immediately, and his urinary function completely recovered. Most reports have characterized postoperative epidural hematoma as occurring early after operation and accompanied with neurological deficits. But it can happen even two weeks after spinal surgery with no pain. Surgeons thus may need to follow up patients for at least a few weeks because some complications, such as epidural hematomas, could take that long to manifest themselves.
Dural sac cross-sectional area (DSCSA) is a way to measure the degree of central spinal canal compression. The objective was to investigate the correlation between the expansion ratio of DSCSA after unilateral laminotomy for bilateral decompression (ULBD) and the clinical results for lumbar spinal stenosis.
We retrospectively reviewed the clinical data and radiographs of 103 patients who underwent ULBD for symptomatic spinal stenosis in one year. We compared preoperative and postoperative clinical data and DSCSA and evaluated the correlation between clinical and radiographic measurements.
There was a significant increase of DSCSA after ULBD (p=0.000) and mean expansion ratio of DSCSA was 203.7±147.2%(range -32.9-826.1%). Clinical outcomes, measured by VAS and ODI were improved significantly not only in early postoperative period, but also in the last follow-up. However, there were no statistically significant correlations between the preoperative DSCSA and clinical symptoms, Perioperative expansion ratio of DSCSA and clinical parameters were also not correlated to the improvement of clinical symptoms significantly in both early postoperative phase and last follow-up.
Our result indicates that the DSCSA itself has a definite limitation to be correlated to the clinical symptoms, and thus meticulous correlation between the clinical presentation and MRI imaging is essential in determination of surgical treatment.
Spinal stenosis; Minimally invasive spinal surgery; Laminotomy; Radiculopathy
A 67-year-old man with degenerative lumbar spinal stenosis and a medical history significant for coronary artery disease underwent routine lumbar surgical decompression. The objective of this study was to report a case of postoperative epidural hematoma associated with the use of emergent anticoagulation, including the dangers associated with spinal decompression and early postoperative anticoagulation.
After anticoagulation therapy for postoperative myocardial ischemia, the patient developed paresis with ascending abdominal paraesthesias. Immediate decompression of the surgical wound was carried out at the bedside. Magnetic resonance imaging revealed a massive spinal epidural hematoma extending from the middle of the cervical spine to the sacrum. Emergent cervical, thoracic, and revision lumbar laminectomy without fusion was performed to decompress the spinal canal and evacuate the hematoma.
Motor and sensory function returned to normal by 14 days postoperatively, but bowel and bladder function continued to be impaired. Postoperative radiographs showed that coronal and sagittal spinal alignment did not change significantly after extensive laminectomy.
Full anticoagulation should be avoided in the early postoperative period. In cases requiring early vigorous anticoagulation, patients should be closely monitored for changes in neurologic status. Combined cervical, thoracic, and lumbar laminectomy, without instrumentation or fusion, is an acceptable treatment option.
Spinal stenosis, lumbar; Spinal decompression; Anticoagulation; Epidural hematoma; Laminectomy
Objective and importance
A rare cause of intracranial hypotension is leakage of cerebrospinal fluid (CSF) through a dural breach from degenerative cervical spine pathology. To our knowledge there have been only four cases described in the English literature. Treatment is challenging and varies from case to case, with complete symptom resolution reported for only one patient. Herein we review the literature and describe our surgical management of a 46-year-old woman with symptomatic intracranial hypotension from the penetration of the cervical thecal sac.
The patient presented with a 3-month history of progressive orthostatic headaches. Magnetic resonance imaging demonstrated bilateral subdural hematomas and pachymeningeal gadolinium enhancement. An anterior epidural CSF collection commencing at a C4–5 calcified disc protrusion and osteophyte was evident on a computed tomography spinal myelogram.
After three unsuccessful lumbar blood patches, we elected to attempt surgical removal of the causative pathology with exposure and primary closure of the dural defect by anterior cervical discectomy as described previously. After resection of the disc–osteophyte complex and dural exposure, immediate high volume egression of CSF mixed with blood at the surgical site. The dural defect was not visible but CSF egression promptly ceased. Cervical corpectomy for greater exposure and primary repair of the defect has been described, but we considered this unwarranted and felt the intraoperative blood collection formed a local blood patch. A collagen dural substitute membrane was inserted through the discectomy space for reinforcement.
Two months after this novel surgical blood patch procedure the patient was asymptomatic and follow-up imaging demonstrated complete resolution.
Spontaneous intracranial hypotension; Cerebrospinal fluid leak; Degenerative spine pathology; Cervical spine
Intracranial hemorrhage is a serious but rare complication of spinal surgery, which can occur in the intracerebral, cerebellar, epidural, or subdural compartment.
To describe patients with intracranial hemorrhage after lumbar spinal surgery and present clinical and diagnostic imaging findings.
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.
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.
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.
Intracranial hemorrhage; Lumbar spine surgery; Remote cerebellar hemorrhage; Subdural hematoma; Epidural hematoma
Symptomatic arachnoiditis after posterior fossa surgical procedures such as decompression of Chiari malformation is a possible complication. Clinical presentation is generally insidious and delayed by months or years. It causes disturbances in the normal flow of cerebrospinal fluid and enlargement of a syrinx cavity in the upper spinal cord. Surgical de-tethering has favorable results with progressive collapse of the syrinx and relief of the associated symptoms.
A 30-year-old male with Chiari malformation type I was treated by performing posterior fossa bone decompression, dura opening and closure with a suturable bovine pericardium dural graft. Postoperative period was uneventful until the fifth day in which the patient suffered intense headache and progressive loose of consciousness caused by an acute posterior fossa epidural hematoma. It was quickly removed with complete clinical recovering. One year later, the patient experienced progressive worsened of his symptoms. Upper spinal cord tethering was diagnosed and a new surgery for debridement was required.
The epidural hematoma compressing the dural graft against the neural structures contributes to the upper spinal cord tethering and represents a nondescribed cause of postoperative fibrosis, adhesion formation, and subsequent recurrent hindbrain compression.
Arachnoiditis; arnold-chiary malformation; dural graft; posterior fossa; tethering
To report the outcomes of a posterior hybrid decompression protocol for the treatment of cervical spondylotic myelopathy (CSM) associated with hypertrophic ligamentum flavum (HLF).
Laminoplasty is widely used in patients with CSM; however, for CSM patients with HLF, traditional laminoplasty does not include resection of a pathological ligamentum flavum.
This study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale.
No hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3±15.5%. Mean cervical lordotic angle had decreased 4.9 degrees by 1 year after surgery (P<0.05). Preservation of cervical range of motion was satisfactory postoperatively. Bone healing rates 6 months after surgery were 100% on the hinge side and 92.2% on the open side. Satisfactory decompression was demonstrated by a significantly increased sagittal canal diameter and cross-sectional area of the dural sac together with a significant drift-back distance of the spinal cord. The dural sac was also adequately expanded at the time of the final follow-up visit.
Hybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF.
Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a rare inflammatory disease characterized by hypertrophic inflammation of the dura mater and various clinical courses that are from myelopathy. Although many associated diseases have been suggested, the etiology of IHSP is not well understood. The ideal treatment is controversial. In the first case, a 55-year-old woman presented back pain, progressive paraparesis, both leg numbness, and voiding difficulty. Initial magnetic resonance imaging (MRI) demonstrated an anterior epidural mass lesion involving from C6 to mid-thoracic spine area with low signal intensity on T1 and T2 weighted images. We performed decompressive laminectomy and lesional biopsy. After operation, she was subsequently treated with steroid and could walk unaided. In the second case, a 45-year-old woman presented with fever and quadriplegia after a spine fusion operation due to lumbar spinal stenosis and degenerative herniated lumbar disc. Initial MRI showed anterior and posterior epidural mass lesion from foramen magnum to C4 level. She underwent decompressive laminectomy and durotomy followed by steroid therapy. However, her conditions deteriorated gradually and medical complications occurred. In our cases, etiology was not found despite through investigations. Initial MRI showed dural thickening with mixed signal intensity on T1- and T2-weighted images. Pathologic examination revealed chronic nonspecific inflammation in both patients. Although one patient developed several complications, the other showed slow improvement of neurological symptoms with decompressive surgery and steroid therapy. In case of chronic compressive myelopathy due to the dural hypertrophic change, decompressive surgery such as laminectomy or laminoplasty may be helpful as well as postoperative steroid therapy.
Idiopathic hypertrophic spinal pachymeningitis; Spinal cord compression; Chronic nonspecific inflammation; Dural thickening
Spinal epidural hematoma is a well known complication of spinal surgery. Clinically insignificant small epidural hematomas develop in most spinal surgeries following laminectomy. However, the incidence of clinically significant postoperative spinal epidural hematomas that result in neurological deficits is extremely rare. In this report, we present a 33-year-old female patient whose spinal surgery resulted in postoperative spinal epidural hematoma. She was diagnosed with lumbar disc disease and underwent hemipartial lumbar laminectomy and discectomy. After twelve hours postoperation, her neurologic status deteriorated and cauda equina syndrome with acute spinal epidural hematoma was identified. She was immediately treated with surgical decompression and evacuation of the hematoma. The incidence of epidural hematoma after spinal surgery is rare, but very serious complication. Spinal epidural hematomas can cause significant spinal cord and cauda equina compression, requiring surgical intervention. Once diagnosed, the patient should immediately undergo emergency surgical exploration and evacuation of the hematoma.
Although postoperative spinal epidural hematoma (SEH) is not uncommon, hematomas that require surgery are rare. Cauda equina syndrome (CES) may be associated with postoperative SEH. In these cases, early recognition and emergency decompression can prevent further damage and better neurologic recovery.
A 41-year-old man underwent two-level discectomy with insertion of an interspinous spacer at L3-4 and L4-5 because of low back pain and radiculopathy. Eight hours after the operation, the patient developed CES. MRI revealed SEH compressing posteriorly at the L3-4 level. On emergency decompression and hematoma evacuation, the interspinous spacer had obstructed the laminotomy site at L3-4 completely, blocking drainage to the drain. The patient experienced complete neurologic recovery by 2 months followup.
Many studies report risk factors for SEH. However, postoperative SEH can also be encountered in patients without these risks. One study reported a critical ratio (preoperative versus postoperative cross-sectional area) correlated with postoperative symptoms, especially in those with CES. The propensity to develop CES is likely dependent on a number of patient-specific factors.
Surgeons should be aware that patients without risk factors may develop acute CES. Wider laminotomy (larger than half of the device size) may help to prevent this complication when one uses the compressible type of device, especially in patients with relatively small lamina.
Study design: A case report.
Objective: To report a rare case of acute spinal subdural hematoma (SSH) complicating lumbar spine surgery, its characteristic presenting symptoms, diagnostic imaging, possible cause, and pitfall in management.
Methods: A 59-year-old woman with lumbar spinal instability and stenosis underwent laminectomy and decompression at L3–L5 with instrumentation and fusion from L3–S1.
Results: Immediately following surgery, the patient presented with incapacitating pain of both lower extremities from the mid-thigh downward, which was not relieved by narcotic analgesia and was disproportional to surgical trauma. Left ankle and great toes weakness was detected at postoperative day 2 and deteriorated on day 6. Magnetic resonance imaging was performed urgently and revealed a characteristic SSH with thecal sac compression at the level of L2, proximal to the laminectomy. Emergency decompression and evacuation of the hematoma was performed. The patient had partial recovery 6 weeks postoperatively.
Conclusion: Acute SSH is a rare complication of lumbar spine surgery. This diagnosis must be considered when severe leg pain, unresolved with analgesia and disproportional to surgical trauma, with neurological deterioration occurring after lumbar spine surgery. Magnetic resonance imaging is the imaging modality of choice to assist in the differential diagnosis of an SSH. Early surgical decompression is necessary for optimal neurological recovery.
We report a series of epidural hematomas which cause neurologic deterioration after spinal surgery, and have taken risk factors and prognostic factors into consideration. We retrospectively reviewed the database of 3720 cases of spine operation in a single institute over 7 years (1998 April-2005 July). Nine patients who demonstrated neurologic deterioration after surgery and required surgical decompression were identified. Factors postulated to increase the postoperative epidural hematoma and to improve neurologic outcome were investigated. The incidence of postoperative epidural hematoma was 0.24%. Operation sites were cervical 3 cases, thoracic 2 cases, and lumbar 4 cases. Their original diagnoses were tumor 3 cases, cervical stenosis 2 cases, lumbar stenosis 3 cases and herniated lumbar disc 1case. The symptoms of epidural hematomas were neurologic deterioration and pain. After decompression, clinical outcome revealed complete recovery in 3 cases (33.3%), incomplete recovery in 5 cases (55.6%) and no change in 1 case (11.1%). Factors increasing the risk of postoperative epidural hematoma were coagulopathy from medical illness or anticoagulation therapy (4 cases, 44.4%) and highly vascularized tumor (3 cases, 33.3%). The time interval to evacuation of complete recovery group (29.3 hours) was shorter than incomplete recovery group (66.3 hours). Patients with coagulopathy and highly vascularized tumor were more vulnerable to spinal epidural hematoma. The postoperative outcome was related to the preoperative neurological deficit and the time interval to the decompression.
Clinical outcome; risk factor; postoperative; spinal epidural hematoma; spine surgery
The authors report a case of symptomatic epidural gas accumulation 2 weeks after the multi-level lumbar surgery, causing postoperative recurrent radiculopathy. The accumulation of epidural gas compressing the dural sac and nerve root was demonstrated by CT and MRI at the distant two levels, L3-4 and L5-S1, where vacuum in disc space was observed preoperatively and both laminectomy and discectomy had been done. However, postoperative air was not identified at L4-5 level where only laminectomy had been done in same surgical field, which suggested the relationship between postoperative epidural gas and the manipulation of disc structure. Conservative treatment and needle aspiration was performed, but not effective to relieve patient's symptoms. The patient underwent revision surgery to remove the gaseous cyst. Her leg pain was improved after the second operation.
Epidural gas; Vacuum phenomenon; Lumbar spine; Recurrent radiculopathy; Spinal surgery
Some reported studies have evaluated the dural sac in patients with lumbar spinal stenosis (LSS) by computed tomography (CT) after conventional myelography or magnetic resonance imaging (MRI). But they have been only able to evaluate static factors. No reports have described detailed dynamic changes in the dural sac during flexion and extension observed by multidetector-row computed tomography (MDCT). The aim of this study was to elucidate or demonstrate, in detail, the influence of dynamic factors on the severity of stenosis.
One hundred patients with LSS were enrolled in this study. All underwent MDCT in both flexion and extension positions after myelography, in addition to undergoing MRI. The anteroposterior diameter (AP-distance) and cross-sectional area of the dural sac (D-area) were measured at each disc level between L1–2 and L5–S1. The dynamic change in the D-area was defined as the absolute value of the difference between flexion and extension. The rate of dynamic change (dynamic change in D-area/D-area at flexion) in the dural sac at each disc level was also calculated.
The average AP-distance in flexion/extension (mm) was 9.2/7.4 at L3–4 and 8.3/7.4 at L4–5. The average D-area in flexion/extension (mm2) was 96.3/73.6 at L3–4 and 72.3/61.0 at L4–5. The values were significantly lower in extension than in flexion at all disc levels from L1–2 to L5–S1. AP-distance was narrowest and D-area smallest at L4–5 during extension. The rates of dynamic changes at L2–3 and L3–4 were higher than those at L4–5.
MDCT clearly elucidated the dynamic changes in the lumbar dural sac. Before surgery, MDCT after myelography should be used to evaluate the dynamic change during flexion and extension, especially at L2–3, L3–4, and L4–5.
Lumbar spinal stenosis (LSS); Dynamic factor; Multidetector-row computed tomography (MDCT); Dural sac
Spontaneous chronic epidural hematomas are extremely rare and can be extremely challenging to diagnose and differentiate. The clinical findings, computed tomographic scan and magnetic resonance imaging does not always enough to complete differentiate this condition. Our purpose is to report a case of a spontaneous chronic epidural hematoma presenting as an extradural mass leading to compressive radicular symptoms with images of bony scalloping which are sparsely reported in the literature.
We describe a 61-year-old woman who was evaluated after 18-month history of pain, disestesias and mild weakness in both lower extremities with significant radicular symptoms on the right side associated to neurogenic claudication.
CT scans revealed a nodular image of soft tissue density located in the right anterolateral epidural space at the L4–L5 level demonstrating resorption of the bony margins. MRI studies revealed a round mass in the vertebral canal displacing the dural sac and scalloping the posterior wall of the L4 vertebral body. Diagnosis was established between a degenerative cyst versus an atypical neurinoma. Surgical findings demonstrated an isolated well-formed chronic hematoma.
Spontaneous chronic epidural hematomas are rare, even more when they produce scalloping of bony structures becoming a diagnostic challenge. Therefore they should be always considered as a differential diagnosis in patients with extradural chronic compressions taking into account that also chronic epidural hematomas can cause bone involvement.
Tumour; Spine, epidural; Hematoma
Because neither the degree of constriction of the spinal canal considered to be symptomatic for lumbar spinal stenosis nor the relationship between the clinical appearance and the degree of a radiologically verified constriction is clear, a correlation of patient’s disability level and radiographic constriction of the lumbar spinal canal is of interest. The aim of this study was to establish a relationship between the degree of radiologically established anatomical stenosis and the severity of self-assessed Oswestry Disability Index in patients undergoing surgery for degenerative lumbar spinal stenosis. Sixty-three consecutive patients with degenerative lumbar spinal stenosis who were scheduled for elective surgery were enrolled in the study. All patients underwent preoperative magnetic resonance imaging and completed a self-assessment Oswestry Disability Index questionnaire. Quantitative image evaluation for lumbar spinal stenosis included the dural sac cross-sectional area, and qualitative evaluation of the lateral recess and foraminal stenosis were also performed. Every patient subsequently answered the national translation of the Oswestry Disability Index questionnaire and the percentage disability was calculated. Statistical analysis of the data was performed to seek a relationship between radiological stenosis and percentage disability recorded by the Oswestry Disability Index. Upon radiological assessment, 27 of the 63 patients evaluated had severe and 33 patients had moderate central dural sac stenosis; 11 had grade 3 and 27 had grade 2 nerve root compromise in the lateral recess; 22 had grade 3 and 37 had grade 2 foraminal stenosis. On the basis of the percentage disability score, of the 63 patients, 10 patients demonstrated mild disability, 13 patients moderate disability, 25 patients severe disability, 12 patients were crippled and three patients were bedridden. Radiologically, eight patients with severe central stenosis and nine patients with moderate lateral stenosis demonstrated only minimal disability on percentage Oswestry Disability Index scores. Statistical evaluation of central and lateral radiological stenosis versus Oswestry Disability Index percentage scores showed no significant correlation. In conclusion, lumbar spinal stenosis remains a clinico-radiological syndrome, and both the clinical picture and the magnetic resonance imaging findings are important when evaluating and discussing surgery with patients having this diagnosis. MR imaging has to be used to determine the levels to be decompressed.
Spine, abnormalities; Spine, MR; Lumbar spinal stenosis; Oswestry Disability Index
Lumbar spinal stenosis is a frequent indication for spinal surgery. The predictive quality of treadmill testing and MRI for diagnostic verification is not yet clearly defined. Aim of the current study was to assess correlations between treadmill testing and MRI findings in the lumbar spine. Twenty-five patients with lumbar spinal stenosis were prospectively examined. Treadmill tests were performed and the area of the dural sac and neuroforamina was examined with MRI for the narrowest spinal segment. VAS and ODI were used for clinical assessment. The median age of the patients was 67 years. In the narrowest spinal segment the median area of the dural sac was 91 mm2. The median ODI was 66 per cent. The median walking distance in the treadmill test was 70 m. The distance reached in the treadmill test correlated with the area of the dural sac (Spearman’s ρ = 0.53) and ODI (ρ = −0.51), but not with the area of the neuroforamina and VAS. The distance reached in the treadmill test predicts the grade of stenosis in MRI but has a limited diagnostic importance for the level of clinical symptoms in lumbar spinal stenosis.
Spinal stenosis; Treadmill test; MRI; Spine; Spinal canal
Closed-suction drainage is commonly used for prevention of postoperative hematoma and associated neurologic compromise after lumbar decompression, but it remains unclear whether suction drainage reduces postoperative complications.
We evaluated the efficacy of closed-suction drainage in single-level lumbar decompression surgery.
Patients and Methods
We retrospectively reviewed 560 patients who underwent single-level lumbar decompression or discectomy. We routinely used closed-suction drainage in all spinal surgeries until July 2003, and thereafter, we did not use drains in single-level lumbar decompression surgery. These two groups (298 patients in the group that received drains, 262 in the group that did not receive drains) were compared for rates of wound infection and epidural hematoma.
Mean operating time (55 versus 56 minutes) and intraoperative blood loss (64 versus 57 mL) were not different between the two groups. None of 560 patients had a wound infection requiring surgical intervention. The rate of postoperative hematoma was 0.7% in the group that received drains (two of 298 patients) and 0% in the group that did not receive drains (zero of 262 patients).
In this study, the risk of wound infection and hematomas in single-level lumbar decompression surgery was not influenced by use of a drain. The use of postoperative wound drainage in patients with potential risk for epidural bleeding in situations such as multiple-level decompression, instrumentation surgery, anticoagulant therapy, trauma, and tumors or metastases needs additional study.
Level of Evidence
Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
Surgery for lumbar spinal stenosis (LSS) is today the most frequently performed procedure in the adult lumbar spine. Long-term benefit of surgery for LSS is well documented both in randomized and in non-randomized trials. In this paper, we present the results from laminarthrectomy as an alternative surgical approach, which have theoretical advantages over other approaches. In this study, we wanted to study the clinical and radiological results of laminarthrectomy. Dural sac cross-sectional areal (DSCSA) is an objective method to quantify the degree of central stenosis in the spinal canal, and was used to measure whether we were able to achieve an adequate decompression of the spinal canal with laminarthrectomy as a surgical approach.
Materials and methods
All patients operated on with this approach consecutively in the period 1 January 2008 to 31 March 2009 were included in the study. All perioperative complications were noted. Clinical results were measured by means of a questionnaire. The patients that agreed to attend the study had an MRI taken of the operated level. DSCSA before and after surgery of the actual level were measured by three observers. We then performed a correlation test between increase of area and clinical results. We also tested for inter- and intra-observer reability.
Fifty-six laminarthrectomy were performed. There were 17 % complications, none of them were life-threatening or disabling. 46 patients attended the study and answered the questionnaire. Thirty-four patients (83 %) reported clinical improvement, whereas six (13 %) patients reported no improvement, and two (4 %) patients reported that they were worse. Mean ODI was 23.0. Mean EQ-5D was 0.77. Mean VAS-score for back-pain was 3.1 and mean VAS-score for leg-pain was 2.8. Mean DSCSA were measured to 80 mm2 before surgery and 161 mm2 after surgery. That gave an increase of DSCSA of 81 mm2 (101 %). We found a significant positive correlation between increase of area and clinical results. We also found consistent inter- and intra-observer reability.
In this study, the clinical results of laminarthrectomy were good, and comparable with other reports for LSS. The rates of complications are also comparable with other reports in spinal surgery. A significant increase in the spinal canal diameter was achieved. Within the limitations a retrospective study gives, we conclude that laminarthrectomy seems to be a safe and effective surgical approach for significant decompressing the adult central spinal canal, and measurement of DSCSA, before and after surgery seems to be a good way to quantify the degree of decompression.
Laminarthrectomy; Lumbar spinal stenosis (LSS); Dural sac cross-sectional areal (DSCSA)
DuraSeal™ (Coviden, Waltham, MA, USA), a hydrogel sealant, is primarily used as an adjunct to a dural repair. Its use has also been described to seal off an annulotomy after a transforaminal lumbar interbody fusion when recombinant human bone morphogenetic protein-2 (rhBMP-2) is used. This aids in the reduction of postoperative radiculitis caused by rhBMP-2. However, as a result of its hydrophilic properties, DuraSeal™ has the potential to swell, which could lead to compression of the thecal sac.
We report a 57-year-old woman who developed cauda equina after a transforaminal lumbar 47 interbody fusion (TLIF) procedure in which the expansion of the DuraSeal™ was believed to be the causative factor. The patient developed urinary retention, bowel incontinence, and paresthesias in the saddle region on postoperative Day 3. She underwent emergent exploration and decompression of the thecal sac. The gel-like DuraSeal™ material was causing significant compression of the thecal sac.
Multiple reports have documented that DuraSeal™, used as an adjunct to dural repair, can swell leading to compression of the spinal cord and/or neural elements. Our case demonstrates the use of DuraSeal™ both over a site of a dural repair and over an annulotomy site, through which a TLIF was performed, is associated with the risk of developing postoperative cauda equina syndrome as a result of swelling of the DuraSeal™.
Those using DuraSeal™ to seal off the annulotomy after a TLIF procedure performed with rhBMP-2 should use the product with an understanding of the potential postoperative swelling of the product and resulting neurologic sequela, particularly if DuraSeal™ is used concomitantly at the site of dural repair.
Lumbar spinal stenosis (LSS) is the common term used to describe patients with symptoms related to the anatomical reduction of the lumbar spinal canal size. However, some subjects may have a markedly narrowed canal without any symptoms. This raises the question of what is the actual role of central canal stenosis in symptomatic patients. The purpose of this study was to compare radiological evaluations of LSS, both visually and quantitatively, with the clinical findings of patients with LSS.
Eighty patients [mean age 63 (11) years, 44% male], with symptoms severe enough to indicate LSS surgery, were included in this prospective single-center study. Lumbar magnetic resonance imaging was performed and one experienced neuroradiologist classified patients into three groups: 0 = normal or mild stenosis, 1 = moderate stenosis, and 2 = severe stenosis. In addition, the same observer measured the minimal dural sac area level by level from the inferior aspect of L1 to the inferior aspect of S1. The association between radiological and clinical findings were tested with Oswestry Disability Index, overall visual analog pain scale, specific low back pain, specific leg pain, Beck Depression Inventory, and walking distance on treadmill exercise test.
In the visual classification of the central spinal canal, leg pain was significantly higher and walking distance achieved was shorter among patients with moderate central stenosis than in patients with severe central stenosis (7.33 (2.29) vs 5.80 (2.72); P = 0.008 and 421 (431) m vs 646 (436) m; P = 0.021, respectively). Patients with severe stenosis at only one level also achieved shorter walking distance than patients with severe stenosis of at least two levels. No correlation between visually or quantitatively assessed stenosis and other clinical findings was found.
There is no straightforward association between the stenosis of dural sac and patient symptoms or functional capacity. These findings indicated that dural sac stenosis is not the single key element in the pathophysiology of LSS.
Spinal stenosis; Magnetic resonance imaging; MRI; Low back pain; Leg pain; Disability; Walking distance
Lumbar spinal stenosis (LSS) treatment is based primarily on the clinical criteria providing that imaging confirms radiological stenosis. The radiological measurement more commonly used is the dural sac cross-sectional area (DSCA). It has been recently shown that grading stenosis based on the morphology of the dural sac as seen on axial T2 MRI images, better reflects severity of stenosis than DSCA and is of prognostic value. This radiological prospective study investigates the variability of surface measurements and morphological grading of stenosis for varying degrees of angulation of the T2 axial images relative to the disc space as observed in clinical practice.
Materials and methods
Lumbar spine TSE T2 three-dimensional (3D) MRI sequences were obtained from 32 consecutive patients presenting with either suspected spinal stenosis or low back pain. Axial reconstructions using the OsiriX software at 0°, 10°, 20° and 30° relative to the disc space orientation were obtained for a total of 97 levels. For each level, DSCA was digitally measured and stenosis was graded according to the 4-point (A–D) morphological grading by two observers.
A good interobserver agreement was found in grade evaluation of stenosis (k = 0.71). DSCA varied significantly as the slice orientation increased from 0° to +10°, +20° and +30° at each level examined (P < 0.0001) (−15 to +32% at 10°, −24 to +143% at 20° and −29 to +231% at 30° of slice orientation). Stenosis definition based on the surface measurements changed in 39 out of the 97 levels studied, whereas the morphology grade was modified only in two levels (P < 0.01).
The need to obtain continuous slices using the classical 2D MRI acquisition technique entails often at least a 10° slice inclination relative to one of the studied discs. Even at this low angulation, we found a significantly statistical difference between surface changes and morphological grading change. In clinical practice, given the above findings, it might therefore not be necessary to align the axial cuts to each individual disc level which could be more time-consuming than obtaining a single series of axial cuts perpendicular to the middle of the lumbar spine or to the most stenotic level. In conclusion, morphological grading seems to offer an alternative means of assessing severity of spinal stenosis that is little affected by image acquisition technique.
Lumbar spinal stenosis (LSS); Imaging; MRI; Lumbar spine; Diagnostic
A comparison of MRI and computed tomography-myelography (CTM) for lumbar intracanalar dimensions. To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the lumbar spine.
Materials and Methods
MRI and CTM of lumbar disc levels from 61 subjects with various lumbar spinal diseases were studied. Dural area, dural anteroposterior (AP) diameter, dural right-left diameter, and thickness of the ligamentum flavum were measured by two orthopedic surgeons. Each section was graded by degree of stenosis. Absolute value and intra- and inter-observer correlation coefficients (ICC) of these measurements and the associations between MRI and CTM values were determined.
Except for MRI determination of ligament flavum thickness, CTM and MRI and intra- and ICC suggested sufficient reproducibility. When measurements of dural area, dural AP diameter, and RL diameter were compared, values in CTM were significantly (p = 0.01-0.004) larger than those in MRI (CTM/MRI ratios, 119%, 111%, and 105%, respectively). As spinal stenosis became more severe, discrepancies between CTM and MRI in measurements of the dural sac became larger.
Both CTM and MRI provided reproducible measurements of lumbar intracanalar dimensions. However, flavum thickness may be more accurately measured by CTM. Because the differences in the measurements between CTM and MRI are very slight and there is very little data to suggest that the precise degree of stenosis is related to symptoms or treatment outcome, the usefulness of the CTM over MRI needs to be confirmed in future studies.
Magnetic resonance imaging; computed tomography; myelography; CTM; lumbar spine; lumbar spinal canal stenosis; diagnosis