Unilateral multilevel interlaminar fenestration instead of laminectomy or hemilaminectomy: an alternative surgical approach to intraspinal space-occupying lesions

Unilateral Biportal Endoscopy for the Resection of Thoracic Intradural Extramedullary Tumors: Technique Case Report and Literature Review

This study describes a patient with an intradural extramedullary (IDEM) tumor removed entirely using the unilateral biportal endoscopic technique (UBE), achieving satisfactory clinical outcomes. A 60-year-old woman had a diagnosis of meningioma with sensations and motor dysfunction in the lower extremities and perineum and gait disturbances for three years, which has worsened over the last month. Preoperative imaging data showed a sizeable IDEM tumor at the T10 level, significantly compressing the thoracic spinal cord to the right side, with 80% intraspinal encroachment. The IDEM tumor was removed entirely by UBE surgery. To the best of our knowledge, this study may be the first to report the application of UBE techniques for IDEM tumor treatment. In this case, UBE provides a magnified and clear surgical field, greater maneuverability, and a less invasive surgical procedure. The procedure objectives were pathological confirmation, spinal cord decompression, and complete tumor removal; all were met. The patient was satisfied with her dramatically improved clinical symptoms. UBE may be an alternative surgical treatment option for benign IDEM tumors presenting with symptomatic, especially the non-giant lateral and posterior tumors.

Hemilaminectomy for the removal of the spinal tumors: An analysis of 901 patients

Objective

We report our experience with the use of hemilaminectomy approach for the removal of benign intraspinal tumors.

Method

A retrospective review of 1,067 patients who underwent hemilaminectomy in our hospital between 2013 and 2019 was analyzed. Baseline medical data were collected. One hundred sixteen patients were excluded due to degenerative diseases, spinal bone tumors, and malignant tumors. The remaining 901 patients (916 tumors) were enrolled. The Dennis Pain Scale (DPS) was used to assess improvement in pain before surgery and during long-term follow-up. Neurological status was assessed using the American Spinal Injury Association (ASIA) impairment scale.

Results

The age of the patients was 48.7 ± 15.3 years, the duration of symptoms was 16.5 ± 32.0 months, and the tumor size was 2.6 ± 1.4 cm. Three hundred two tumors were located in the cervical region, 42 in the cervicothoracic region, 234 in the thoracic region, 57 in the thoracolumbar region, and 281 in the lumbar and lumbosacral region. Twenty-three tumors were ventrally located, 677 were dorsal or dorsolateral, 63 were intramedullary, 87 were epidural, and the rest were dumbbell-shaped. The most common pathologies were schwannomas (601, 66.7%) and meningiomas (172, 19.1%). Total excision was achieved at 97.8%. The operative time was 94.3 ± 32.6 min and the blood loss during surgery was 96.9 ± 116.5 ml. The symptom of pain improved in 87.0% of patients during long-term follow-up, neurological function improved in 68.3% and remained unchanged at 30.5%.

Conclusion

The hemilaminectomy approach was a rapid and safe procedure to remove intradural and extradural tumors. This approach has offered several advantages. It could be used for the resection of most extradural or intradural extramedullary lesions, even some intramedullary tumors.

Application of open-door laminoplasty with ARCH plate fixation in cervical intraspinal tumors

BACKGROUND

The open-door laminoplasty is an effective procedure for the treatment of cervical spondylotic myelopathy. However, little information is available about the surgical results of open-door laminoplasty in the treatment of intraspinal tumors. In the present study, we aimed to investigate the clinical effect of open-door laminoplasty with ARCH plate fixation in the treatment of cervical intraspinal tumors.

METHODS

This was a retrospective study. From January 2013 to May 2018, 38 patients (13 males and 25 females, the average age of 44 ± 17 years) with cervical intraspinal tumors underwent open-door laminoplasty with ARCH plate fixation in our hospital. The operation time, blood loss, pre- and postoperative visual analog scale (VAS), and Japanese Orthopedic Association (JOA) scores were determined. To determine the radiographic outcomes, cervical X-ray film and magnetic resonance imaging (MRI) were performed before and after the operation, and cervical X-ray sagittal film was used to measure Cobb angle. The clinical data before and after the operation were compared by t-test.

RESULTS

A total of 38 patients underwent a successful operation and demonstrated primary healing. The average operation time was 113 ± 12 min. The average blood loss was 120 ± 19 mL. All patients were followed up for 26.1 ± 2.8 months, and the final follow-up time was more than 24 months. VAS scores were much better at 24 months after operation compared with those before the operation, which were decreased from 6.1 ± 1.1 to 1.4 ± 0.7 (t = 32.63, P < 0.01). The JOA score was improved from 9.9 ± 1.5 to 15.5 ± 0.6 (t = - 18.36, P < 0.01), and the mean JOA recovery rate was 79% ± 11% at 24 months after the operation. There was no significant difference in Cobb angle between pre-operation and 24 months after the operation, which was 9.8 ± 2.6 and 10.3 ± 3.1 respectively (t = - 0.61, P > 0.05). Neither spinal malalignment on the coronal plane nor displacement of the laminoplasty flap was observed on postoperative cervical X-ray and MRI examinations at the final follow-up.

CONCLUSIONS

Open-door laminoplasty with ARCH plate fixation was a safe and effective surgical approach for the treatment of cervical intraspinal tumors.

Abordaje mínimamente invasivo para el tratamiento de tumores espinales intradurales extramedulares: Nota Técnica

Objetivo:

Describir la técnica de abordaje mínimamente invasiva para el tratamiento de tumores intradurales extramedulares en los diferentes segmentos espinales.

Material y Métodos:

Se detallan la planificación, posicionamiento, marcación, pasos técnicos del abordaje mínimamente invasivo, exéresis lesional y cierre de lesiones ID-EM a nivel cervical, dorsal, lumbar y sacro. Se proporcionan recomendaciones para descomplejizar maniobras quirúrgicas, acortar el tiempo operativo y evitar potenciales complicaciones.

Conclusiones:

El abordaje MISS es una opción segura y eficaz para el tratamiento quirúrgico de determinados tumores ID-EM.

Application of Laminoplasty Combined with ARCH Plate in the Treatment of Lumbar Intraspinal Tumors

Objective

To investigate the bone fusion and clinical effect of laminoplasty combined with ARCH plate fixation in the treatment of lumbar intraspinal tumors.

Methods

This was a clinical study. From June 2017 to January 2019, 24 patients (seven males and 17 females, average age 40 ± 16 years) with lumbar intraspinal tumors underwent laminoplasty combined with ARCH plate fixation in our hospital. The bone fusion was evaluated by X‐ray and computed tomography (CT) scans that were taken 15.2 ± 2.17 months postoperatively. Each segment showed a bone bridge on one side, which was classified as “segmental partial fusion.” Each segment showed bilateral bone bridges, which were classified as “segmental complete fusion”. When all segments of the patient showed bilateral bone bridging so that the replanted lamina and the host lamina became a unit on the CT scan, it was defined as “complete fusion”. In addition, the operation time and blood loss were recorded. Fisher's exact test was used to analyze the potential influencing factors of bone healing, including age (≤40 years vs >40 years), gender, number of operated levels (single vs two). Paired t‐test was used to analyze pre‐ and postoperative Oswestry Disability Index (ODI) scale and low back and leg pain visual analog scale (VAS).

Results

A total of 33 segments of laminoplasty were successfully performed in 24 patients. The average operation time was 128 ± 18 minutes. The average blood loss was 110 ± 19 mL. All patients were followed up at least 12 months after operation (average, 15.2 ± 2.17 months). At the final follow‐up, according to the definition of this study, the proportion of “segmental partial fusion” and “segmental complete fusion” were 30.3% (10/33) and 69.7% (23/33), respectively. And the proportion of patients with “complete fusion” was 70.8% (17/24). Age, gender, and number of operated levels were not associated with the fusion (P = 1.0, 0.37, and 0.06, respectively). ODI and VAS were much better at 1 month after operation and the final follow‐up than those before the operation (P < 0.01). At 6 months after operation, the results of magnetic resonance imaging (MRI) showed that the supraspinous ligament was repaired, and there were no complications, such as spinal epidural scar recompression.

Conclusions

Laminoplasty combined with ARCH plate was a better surgical method, and 70.8% of the patients showed complete bone fusion and there was no case of bilateral nonunion.

Surgical Treatment Outcomes of Patients with Conus Medullaris Teratoma: A Single-Center Experience of 39 Patients

OBJECTIVE

Conus medullaris teratomas are extremely rare, and the treatment experience has been limited. The purpose of the present study was to evaluate the clinical characteristics, radiological features, surgical outcomes, and prognosis of patients with conus medullaris teratoma.

METHODS

We retrospectively reviewed the data from 39 patients who had undergone surgical resection for conus medullaris teratomas from January 2008 to December 2018. All the operations were performed by 1 senior doctor. The clinical features, pre- and postoperative magnetic resonance imaging findings, pathological features, treatment strategies, and outcomes were analyzed. The neurological status was evaluated using the modified Japanese Orthopaedic Association scale score.

RESULTS

Of the 39 patients, the mean age was 30.9 years. Of the 39 patients, 20 were male and 19 were female. The symptom duration ranged from 0.3 to 252 months (mean, 61.6 months). Bladder and bowel dysfunction was the most common symptom (76.9%). Total resection was achieved in 25 patients (64.1%), subtotal resection in 11 (28.2%), and partial resection in 3 (7.7%). A mature teratoma was confirmed in all 39 patients. The neurological outcomes were improved 16 patients (45.7%), stable in 14 (40.0%), and aggravated in 5 (14.3%) at a mean follow-up of 62.7 months. Recurrence developed in 1 patient who had undergone subtotal resection. A second surgery with total resection was performed, and the patient's neurological symptoms were stable during follow-up.

CONCLUSIONS

Total surgical resection is the optimal treatment strategy for patients with conus medullaris teratoma. Safe maximum tumor removal and residual tumor inactivation using electrocoagulation are recommended when total resection cannot be achieved. Surgery can provide a low recurrence rate and an acceptable low complication rate.

Spinal meningiomas

Spinal meningiomas are typically slow growing, benign lesions with the potential to cause significant morbidity if untreated. Their incidence is approximately 3 per 100,000 and they are more common in women than in men. Surgical resection has a relatively low complication rate and the potential for very favorable outcomes. Surgery remains the mainstay of treatment with radiation reserved for those who cannot tolerate the procedure or for recurrent disease. We describe the epidemiology, presentation, and treatment options for spinal meningiomas here as well as provide an example case.

Unilateral Hemilaminectomy for Intradural Lesions

OBJECTIVE

Unilateral hemilaminectomy (UHIL), an alternative surgical approach to intradural lesions, involves a unilateral approach to meningeal opening that provides an adequate window for tumor extraction while leaving most of the vertebral structures intact. The techniques and results of a modified hemilaminectomy technique with spinal endoscopy is discussed and limited unilateral hemilaminectomy for intradural tumors (UHIT) evaluated prospectively.

METHODS

Relevant clinical variables, operative reports, histological findings, pre- and post-operative imaging, and follow-up data for 11 consecutive patients (five males, six females; mean age 63.36 ± 20.69 years) who underwent modified hemilaminectomy over a 3 year time period were analyzed. Contrast-enhanced MRI was used to demonstrate the side, size and location of the suspected tumor or intradural lesion and CT to evaluate the bone anatomy. Post-operative MRI and CT allowed evaluation of anatomy following resection.

RESULTS

Lesions included meningiomas (n = 2), neuromas (n = 3), and metastases, cysts or gliomas (n = 6). Pre-operative indications in order of incidence included cord compression, claudication, lower back pain, radiculopathy, paraplegia, weakness, incontinence, and generalized neuro-deterioration. There were no major complications, and no spinal deformity or instability at final follow up (mean, 13 months; range, 3-36 months).

CONCLUSION

Our data suggest that there is a place for the UHIT approach. This minimally invasive approach is useful for resecting all intradural tumors. UHIL is a useful minimally invasive technique for resecting intradural spinal tumors with maximal preservation of musculoligamentous attachments and posterior bony elements and should be considered an improvement on currently employed techniques.

Retrospective observational comparative study of Hemilaminectomy versus Laminectomy for intraspinal tumour resection; Shorter Stays, Lower Analgesic Usage and Less Kyphotic Deformity

INTRODUCTION

Intraspinal tumours are rare and principally managed surgically. Laminectomy, employed for access to the spinal canal, destroys the posterior tension band leading to a risk of kyphosis. Hemilaminectomy as an alternative may be less destructive, potentially reducing the risk of deformity and causing less post-operative pain.

METHOD

We investigated this hypothesis by retrospectively reviewing a case series of 56 surgeries for a disparate and unselected group of intraspinal tumours utilizing a laminectomy or hemilaminectomy approach.

RESULTS

No difference was found in length of operation, completeness of resection, complication rate and Frankel-score improvements. Hemilaminectomy (n = 22) is associated with reduced hospital stay (post-op days) 4.5 (2-6) versus 6 (3-8), (p = 0.026, Mann-Whitney), and a reduction in post-operative morphine use (mg) 10 (3.5-28) versus 30 (10-90), (p = 0.005, Mann-Whitney). Post-operative kyphosis was measured with the Harrison posterior tangent method on T2-weighted sagittal MR images. The average change in kyphosis angle was greater in the laminectomy group compared with the hemilaminectomy group, 3.6 (0.8-6.2) versus 0.4 (-0.2-1.2), statistically significant (p = 0.004, Mann-Whitney).

CONCLUSION

Hemilaminectomy is as effective an access procedure for the resection of unselected intraspinal tumours as laminectomy, but is associated with shorter post-operative stays, lower analgesic requirements and less post-operative kyphosis.

Novel surgical approach in the management of longitudinal pathologies within the spinal canal: the split laminotomy and "archbone" technique: alternative to multilevel laminectomy or laminotomy

Multilevel laminectomy to open the spinal canal carries the risk of spinal deformities and instability. With the aim of preserving and reconstructing the posterior structures the authors developed a novel, minimally invasive, multilevel spinous process splitting and distracting laminotomy approach with or without complementary corticocancellous iliac crest or PEEK cage "archbone" grafting. The technique allows exploration of the spinal canal and the removal of intramedullary pathologies. Moderate enlargement of the spinal canal with preservation of the majority of posterior structures is also possible, so that muscle attachments remain intact and postoperative complications are substantially reduced.This surgical approach, while fulfilling the requirements of previous laminotomy techniques, helps to prevent damage to the crucial posterior stabilizers of the spine. In contrast to conventional spinal canal approaches, preservation of the majority of posterior structures is possible, leaving muscle attachments on the spinous processes and laminae completely intact.Furthermore, the procedure for exposure and decompression of the spinal canal is a suitable method for all spinal segments, the cervical, thoracic, and the lumbar spine in all age groups.

Surgery for primary filum terminale ependymomas: outcome and prognostic factors

INTRODUCTION

Primary filum terminale ependymoma (PFTE) is a unique type of ependymomas and locates on extramedullary site. However, the clinical features and prognostic factors of PFTE are still unknown due to its rarity.

AIM

This study aimed to evaluate the clinical features, outcomes, and prognostic factors of PFTE in the largest series of cases.

RESULT

Thirty-eight patients were included in this study. Gross total removal (GTR) of the tumors was achieved in 33(87%) patients. Five (13%) patients had subtotal resection (STR). For the residual tumors, postoperative radiotherapy increased the interval between the first surgery and tumor regrowth (P = 0.063). Six patients had local recurrence/progression. Univariate analysis identified STR(P = 0.001), unencapsulated tumor (P = 0.018), tumor involving more than two vertebral columns (P = 0.005), and tumor invading sacral canal(P < 0.001) as predictors of tumor recurrence. In addition, 36 (95%) patients had stable or improved neurological status directly after surgery. Klekamp-Samii score was better correlated with the symptoms than McCormick scale.

CONCLUSION

Extent of surgical removal, tumor size, tumor location, and the integrity of tumor capsule are the prognostic factors of PFTEs, and the intrasacral PFTEs always have a poor prognosis.

Biomechanical comparison of laminectomy, hemilaminectomy and a new minimally invasive approach in the surgical treatment of multilevel cervical intradural tumour: a finite element analysis

PURPOSE

The objective of this study was to investigate the impact of the less invasive procedures of hemilaminectomy and unilateral multilevel interlaminar fenestration (UMIF) on the cervical spinal biomechanics.

METHODS

A validated nonlinear finite element model of the intact cervical spine (C2-C7) was modified to study the biomechanical changes as a result of surgical alteration for treatment of intradural tumours at C3-6 using multilevel laminectomy (ML), multilevel hemilaminectomy (MHL) and UMIF with or without unilateral graded facetectomy.

RESULTS

Under the load-controlled method, the greatest biomechanical changes occurred at the surgical segments. The largest increases occurred in flexion motions following ML approach with 70, 62 and 60 % increase at C3-4, C4-5 and C5-6, respectively. The increases were significantly reduced to no more than 14 % under MHL and UMIF. When combined with graded facetectomy, the changes in flexion under ML approach have a significantly further increase, up to 110 % at C3-4. The further increase was not significantly following MHL and UMIF, with no more than 31 % increase at C3-4, C4-5 and C5-6. The motion following UMIF was only slightly smaller in axial rotation than MHL. The maximum stresses in the annulus occurred during flexion in ML model, with 39, 34 and 38 % more stress than the intact at C3-4, C4-5 and C5-6, respectively. The increases of stress were significantly reduced to 5-7 % under MHL and UMIF.

CONCLUSIONS

The less invasive approaches of UMIF and MHL greatly preserved the flexion motion (more than 48 %) of the cervical spine compared with laminectomy, and the preserved motion mean the low-risk of postoperative spinal instability. UMIF and MHL also reduced the increased stress of annulus caused by ML, and the lesser stress will lower the risk of postoperative disc degeneration. The posterior bone elements play a slight role in spinal stability after removal of the attached ligaments.

Unilateral, multilevel, interlaminar fenestration in the removal of a multisegment cervical intramedullary ependymoma

BACKGROUND CONTEXT

Laminectomy is the traditional approach to intramedullary ependymomas and may lead to spinal instability and spinal deformities. Hemilaminectomy and laminoplasty have been developed to preserve the spinal stability and have been found to be effective. Unilateral, multilevel, interlaminar fenestration is another approach that may have more advantages in preserving the spinal stability; however, it has rarely been used by now.

PURPOSE

Unilateral, multilevel, interlaminar fenestration was often used in the surgical treatment of degenerative lumbar stenosis; however, it was rarely used for tumors. The aim of this study was to discuss the characteristics and advantages of its use for a multisegment intramedullary ependymoma.

STUDY DESIGN

Case report and literature review.

METHODS

The 22-year-old man suffered from muscular atrophy of the left hand and the right hand for a period of 1.5 years and 3 months, respectively, and the cervical magnetic resonance imaging revealed an intramedullary mass of C4-C7. A right, unilateral, multilevel, interlaminar fenestration of the C3-C7 was performed with the help of high-speed air drills, and a midline myelotomy was made under microscope. The tumor was removed totally using piecemeal resection.

RESULTS

The magnetic resonance imaging, obtained 1 year after the operation, revealed that there were no residual mass lesion and no spinal instability, and the patient acquired an excellent functional outcome. So, this technique proved to be safe and easy in this case.

CONCLUSIONS

Unilateral, multilevel, interlaminar fenestration allows good access to a long intraspinal segment, protects the structures essential to spinal stability as much as possible, preserves the spinal stability, and results in no additional injury to the spinal cord. It may be applicable to many other kinds of intraspinal tumors.

Application of the hemi-semi-laminectomy approach in the microsurgical treatment of C2 schwannomas

STUDY DESIGN

Retrospective analysis of 9 cases of C2 schwannomas who were treated microsurgically with hemi-semi-laminectomy approach.

OBJECTIVE

To review the clinical data and describe several operative nuances and pearls from our experience about the hemi-semi-laminectomy approach that provided successful resection of C2 schwannomas.

SUMMARY OF BACKGROUND DATA

Compared with hemi-laminectomy, the hemi-semi-laminectomy is a more minimally invasive approach for excising spinal neurinomas, which can preserve as much of the mechanically relevant bone structures and facet joints as possible. There are no previous reports about the resection of C2 schwannomas with the hemi-semi-laminectomy approach.

METHODS

Between June 2006 and February 2011, a consecutive series of 9 patients underwent surgery for C2 schwannomas. All patients were treated microsurgically with a midline posterior hemi-semi-laminectomy approach. Data regarding age, sex, duration and type of symptoms, topographical locations, and surgical results were investigated retrospectively.

RESULTS

Of the 9 C2 schwannomas, 8 were located both intradurally and extradurally (dumbbell shaped), and 1 was located extradurally. The initial symptom was numbness of the extremity in 7 patients, neck pain in 1 patient, and clumsiness of the upper extremity in 1 patient. The average duration from initial symptom to surgery was 7.9 months. The average follow-up time was 39.6 months. There were no major surgical complications and tumor recurrence during the follow-up period. Remarkable neurological recovery was observed in 9 patients.

CONCLUSIONS

The hemi-semi-laminectomy is a more minimally invasive approach that can preserve as much of the mechanically relevant bone structures as possible, so that the integrity of the arch of the atlas and the lamina of C2 can be maintained. This approach can provide sufficient field for the resection of the C2 schwannomas that do not extend to the ventral side of the vertebral artery in the anterolateral direction. The minimally invasive access and the remarkable results associated with this approach make it a valid alternative in selected cases.

Less invasive approaches for the treatment of cervical schwannomas: our experience

PURPOSE

The purpose of our paper is to illustrate our experience with minimally invasive approaches for the treatment of cervical schwannomas. Moreover, a brief review of the literature was conducted.

METHODS

All data regarding patients treated for cervical schwannomas were retrospectively revised. Site, size and extension of the lesions and preoperative neurological status were obtained through re-examination of neuroimaging and clinical records. Postoperative clinical examinations and radiological images were available for all patients. The clinical course was documented using the visual analog scale (VAS), Karnofsky score (KPS) and the Klekamp-Samii score system.

RESULTS

Sixteen patients harboring cervical schwannomas were treated from 2003 to 2009. Hemilaminectomy was performed in eight cases, subtotal hemilaminectomy in four cases, interlaminar fenestration in two cases, osteoplastic hemilaminotomy and laminoplasty in one case each. Postoperative neuroimaging revealed complete removal of the lesion and no signs of spinal instability. At discharge, neurological improvement was observed in 14 patients and all patients demonstrated reduction of VAS score and improvement of KPS and Klekamp-Samii's score.

CONCLUSIONS

Minimal access procedures are increasingly gaining popularity but their use is poorly described in the treatment of cervical tumors. Less invasive approaches may effectively be used instead of traditional laminectomy in the treatment of cervical tumors, especially schwannomas, providing less iatrogenic traumatism and preventing postsurgical spinal instability. Modern neuroimaging allows adequate preoperative planning and microsurgical techniques provide adequate execution of the surgical act. The procedure has to be tailored case by case considering the specific lesional features and the individual anatomical situation.

Unilateral hemilaminectomy for patients with intradural extramedullary tumors

A modified hemilaminectomy was introduced in an attempt to explore the operative techniques and the values of the limited approach to spinal cord tumors. Forty-five consecutive patients with intradural extramedullary lesions, who underwent modified hemilaminectomy, were studied retrospectively. The intraspinal tumors were removed via the limited bone window with a 3.3-cm mean length (range: 2.0-6.5 cm) and a 1.2-cm mean width (range: 0.6-1.5 cm), in which the inner parts of the medial and lateral laminae were mostly undercut for wider view. Spinal lesions were cervical in 21 cases, thoracic in 12 cases, lumbar in 10 cases, and multiple in 2 cases. Forty-three cases were completely excised via hemilaminectomy alone. Two subjects with dumbbell neurinoma underwent two-stage tumor removal via anterolateral cervical approach following hemilaminectomy. With respect to neurological status, the percentage of good Frankel scale (D+E grade) was markedly improved from 22.2% on admission to 93.3% at follow-up. At the median 26-month follow-up evaluation by magnetic resonance imaging (MRI), none of the subjects showed spinal deformity or instability. By preserving musculoligamentous attachments and posterior bony elements as much as possible, the modified approach is minimally invasive and may be routinely used to remove intradural and extramedullary tumors, especially in patients with meningiomas and neurinomas.

Profiles of Spinal Cord Tumors Removed through a Unilateral Hemilaminectomy

OBJECTIVE

To present the profiles of spinal cord tumors that can be removed through a unilateral hemilaminectomy and to demonstrate its usefulness for benign spinal cord tumors that significantly occupy the spinal canal.

METHODS

From June 2004 to October 2010, 25 spinal cord tumors were approached with unilateral hemilaminectomy. We calculated the cross-sectional occupying ratio (CSOR) of tumor to spinal canal before and after the operations.

RESULTS

The locations of the tumors were intradural extramedullary in 20 cases, extradural in 2, and intramedullary in 3. The levels of the tumors were lumbar in 12, thoracic 9, and cervical 4. In all cases, the tumor was removed grossly and totally without damaging spinal cord or roots. The mean height and width of the lesions we195re 17.64 mm (3-47.5) and 12.62 mm (4-32.7), respectively. The mean CSOR was 69.40% (range, 27.8-96.9%). Postoperative neurological status showed improvement in all patients except one whose neurologic deficit remained unchanged. Postoperative spinal stability was preserved during the follow-up period (mean, 21.5 months) in all cases. Tumor recurrence did not develop during the follow-up period.

CONCLUSION

Unilateral hemilaminectomy combined with microsurgical technique provides sufficient space for the removal of diverse spinal cord tumors. The basic profiles of the spinal cord tumors which can be removed through the unilateral hemilaminectomy demonstrate its role for the surgery of the benign spinal cord tumors in various sizes.

A comparison of mini-open and open approaches for resection of thoracolumbar intradural spinal tumors

Object

Standard approaches to thoracic intradural tumors often involve a large incision and significant tissue destruction. Minimally invasive techniques have been applied successfully for a variety of surgical decompression procedures but have been rarely used for the removal of intradural thoracolumbar tumors. In this paper, the authors compare the clinical outcome of mini-open resection of intradural thoracolumbar tumors with a standard open technique.

Methods

The authors retrospectively reviewed their series of 18 consecutive mini-open thoracolumbar, intradural, tumor resection cases and compared the outcomes with a profile-matched cohort of 9 cases of open intradural tumor resection. Operative statistics, functional outcome, and complications were compared.

Results

Tumors were removed successfully using both approaches, except for 1 case in the mini-open cohort in which only biopsy was performed for a diffusely infiltrating tumor (glioblastoma). There was no statistically significant difference in operative duration, American Spinal Injury Association scale score improvement, or back pain visual analog scale score improvement between groups. However, the mini-open group demonstrated a significantly lower estimated blood loss (153 vs 372 ml, respectively) and a significantly shorter length of hospitalization (4.9 vs 8.2 days, respectively). There was 1 complication of pseudomeningocele formation in the mini-open cohort and 1 complication of cerebral infarction in the open cohort. Mean follow-up length was 16 months in the mini-open group compared with 20 months in the open group.

Conclusions

The mini-open approach allows for adequate treatment of intradural thoracolumbar tumors with comparable outcomes to standard, open approaches. The mini-open approach is associated with less blood loss and a shorter length of stay compared with standard open surgery.

Microsurgical resection of cavernous haemangioma around the thoracic neuroforamen: a case report

Treatment for haemangioma of the spinal cord often results in extensive bony resection that necessitates fusion and/or instrumentation. We report on a 75-year-old man who presented with neuropathic pain and muscle weakness of both lower limbs, secondary to an epidural haemangioma at T11-T12, extending laterally into the neuroforamen. The tumour was resected within the neuroforamen after a partial laminectomy and limited medial foraminotomy at T11-T12, without disruption of the osseous continuity of the pars interarticularis, avoiding spinal stabilisation surgery.

The effect of bilateral laminotomy versus laminectomy on the motion and stiffness of the human lumbar spine: a biomechanical comparison

STUDY DESIGN

A cadaveric simulation model of the lumbar spine was used to study the intervertebral motion characteristics of the lumbar spine after bilateral laminotomy and facet-sparing laminectomy.

OBJECTIVE

To assess differences in motion patterns and lumbar spine stiffness after bilateral laminotomy versus laminectomy.

SUMMARY OF BACKGROUND DATA

Spondylolisthesis after facet-sparing laminectomy has been reported with a frequency of 8% to 31%. Bilateral laminotomies have been shown to be effective in decompressing the spine, without resection of the posterior osteo-ligamentous complex. We hypothesize that bilateral laminotomies induce significantly less iatrogenic hypermobility and less stiffness reduction than a traditional facet-sparing laminectomy in the lumbar spine.

METHODS

Six fresh frozen human cadaveric lumbar spines (L1-L5) were mounted into a spine motion simulator for testing. With physiologic follower preload, flexion/extension, lateral bending, and axial rotation moments were applied to the lumbar spine in 3 trials: (1) Intact lumbar spine-no surgery, (2) Lumbar spine after bilateral lumbar laminotomies at L2-L5, (3) Lumbar spine after full laminectomies at L2-L5. The lumbar spine kinematics were measured using a Vicon motion tracking system. Total and segmental range of motion and spine stiffness were recorded.

RESULTS

In flexion/extension, bilateral laminotomies resulted in an average increase in L2-L5 range of flexion/extension motion of 14.3%, whereas a full laminectomy resulted in an increase of 32.0% (P<0.05). Analysis per level demonstrated roughly twofold increase in motion with laminectomy compared with bilateral laminotomies (P<0.05, at every treated level). Stiffness was decreased by an average of 11.8% after the 3-level-laminotomies and by 27.2% (P<0.05) after the 3-level-laminectomy.

CONCLUSION

These data demonstrate that bilateral laminotomies induce significantly less hypermobility and less stiffness reduction compared with a full laminectomy. The preservation of the central posterior osteo-ligamentous structures may provide a stabilizing effect in preventing postdecompression spondylolisthesis.

Minimally invasive resection of intramedullary ependymoma: case report

OBJECTIVE

This report illustrates the adequacy of minimally invasive exposure for the resection of an intramedullary ependymoma.

CLINICAL PRESENTATION

The patient presented with a history of upper back pain, but a lesion was found during a workup for increased back pain after a motor vehicle accident.

INTERVENTION

The intramedullary ependymoma was approached using a muscle-splitting retractor and extended hemilaminar exposure. The tumor was removed using conventional techniques.

CONCLUSION

This minimally invasive exposure is adequate for selected intramedullary lesions and may be especially useful in patients with a high risk of postlaminectomy deformity.

Biomechanical comparison of traditional and minimally invasive intradural tumor exposures using finite element analysis

BACKGROUND

Minimally invasive approaches to intradural pathology have evolved in part in an effort to reduce approach related destabilization of the spine. No biomechanical data exist however evaluating the effects of traditional and minimally invasive exposures.

METHODS

A finite element model of the lumbar spine was generated, and a simulated open laminectomy and a modified hemilaminectomy at L4 were performed. Forces were applied to assess changes in flexion, extension, axial rotation, and lateral bending.

FINDINGS

Open laminectomy produced much greater changes in extension, flexion, and axial rotation than the modified hemilaminectomy from the intact. Lateral bending was similarly unaffected for both exposures.

INTERPRETATION

The results suggest that a minimally invasive hemilaminar exposure preserves the structural integrity of the lumbar spine and minimizes alterations to segmental motion postoperatively.

Multiple short-segment laminoplasties in children: a novel technique to avoid postoperative spinal deformity

INTRODUCTION

Spinal deformity is a recognized important complication after laminectomies, especially in children. Even with laminoplasties, spinal deformity is a concern, especially when laminoplasties involve multiple levels. The author reports a novel technique to avoid postoperative spinal deformity using multiple short-segment replacement laminoplasties to access pathology over a long segment of the intraspinal space.

REPORT

The technique was used to evacuate an organized extradural hematoma from C4 to T9 in a 9-month-old infant with incomplete quadriplegia. Three separate, short-segment, and superiorly reflected laminoplasties (C5-C7; T2-T4; T6-T8) were performed, leaving intact the laminae (T1; T5) between each laminoplasty flap. At 1 year postoperatively, there was complete neurological recovery and no spinal deformity. The laminae re-fused anatomically.

CONCLUSIONS

Multiple short-segment laminoplasties allow good access to a long intraspinal segment, may preserve the stability of the spine, prevent spinal deformity, allow good reconstitution of the laminar anatomy, and facilitate surgical stabilization should that be required in the future. This technique may be applicable to other intraspinal lesions, such as tumors.