Results and complications after 2-level axial lumbar interbody fusion with a minimum 2-year follow-up

J Neurosurg: Spine / July 17, 2012. DOI: 10.3171/2012.6.SPINE11915

Axial lumbar interbody fusion (AxiaLIF) is a minimally invasive presacral surgical technique that damages neither the anulus fibrosus nor the anterior or posterior longitudinal ligaments. The technique was initially designed and used for L5–S1 interbody fusions and recently was extended to 2-level fusions (L4–5 and L5–S1). Until now, only biomechanical and radiological studies have discussed the feasibility of this new indication, and no clinical study has been published. The purpose of this article is to report results and complications associated with 2-level presacral AxiaLIF with a minimum of 24 months of follow-up.

METHODS
In this prospective, nonrandomized, single-center study, 27 patients underwent presacral AxiaLIF surgery at the L4–5 and L5–S1 levels. Clinical outcomes were assessed using the visual analog scale for back and leg symptoms and the Oswestry Disability Index. Radiographic parameters, such as disc height, segmental lordosis, and bone fusion, were analyzed using radiographs and CT scans. Complications and revision surgeries were recorded as needed. The minimum follow-up was 24 months (up to 72 months).

RESULTS
There were no intraoperative complications. One major complication was observed: a patient developed septicemia that resolved after proper care. Clinical outcomes scores showed overall improvement in pain and physical function. During follow-up, the following complications were observed in the construct: screw breakage (14.8%), proximal/distal transsacral rod detachment (11.1%), radiolucency around the transsacral rod (52%), and cephalic rod migration (24%). Disc height gain was reported early after surgery, but at the 24-month follow-up the disc space was diminished in comparison with the preoperative status. Compared with preoperative values, the 24-month results showed loss of segmental lordosis. Only 22% of all treated levels were considered to have solid fusion at the 24-month radiological evaluation.

CONCLUSIONS
Patients undergoing presacral 2-level AxiaLIF experienced satisfactory short-term clinical outcomes; however, complications were commonly seen on imaging studies obtained 24 months postoperatively. Additional studies are required to better understand the 2-level indications for this technique.

Axial Loading During Magnetic Resonance Imaging in Patients With Lumbar Spinal Canal Stenosis

SPINE Volume 37, Number 16, pp E-985–E992

We compared the sizes of the dural sac among conventional magnetic resonance imaging (MRI), axial loaded MRI, and upright myelography in patients with lumbar spinal canal stenosis (LSCS).

Objective. To determine whether axial loaded MRI can demonstrate similar positional changes of the dural sac size as were detected by upright myelography in LSCS.

Summary of Background Data. In patients with LSCS, constriction of the dural sac is worsened and symptoms are aggravated during standing or walking. To disclose such positional changes, upright myelography has been widely used. Recently, axial loaded MRI, which can simulate a standing position, has been developed. However, there has been no study to compare the dural sac size between axial loaded MRI and upright myelography.

Methods. Forty-four patients underwent conventional MRI, axial loaded MRI, and myelography. Transverse and anteroposterior diameters and the cross-sectional areas of the dural sac from L2– L3 to L5–S1 were compared. Pearson correlations of the diameters between the MRIs and the myelograms were analyzed. On the basis of the myelograms, all disc levels were divided into severe and nonsevere constriction groups. In each group, the diameters and the cross-sectional areas were compared. Sensitivity and specifi city to detect severe constriction were calculated for the conventional and axial loaded MRI.

Results. Transverse and anteroposterior diameters at L4–L5 in the axial loaded MRI and myelogram were signifi cantle smaller than those observed in the conventional MRI ( P < 0.001). Crosssectional areas in the axial loaded MRI were signifi cantly smaller than those in the conventional MRI at L2–L3, L3–L4, and L4–L5 ( P < 0.001). Between the axial loaded MRI and the myelography, Pearson correlation coeffi cients of the transverse and anteroposterior diameters were 0.85 and 0.87, respectively ( P < 0.001), which were higher than those for conventional MRI. Reductions of the dural sac sizes in the axial loaded MRI were more evident in the severe constriction group. The axial loaded MRI detected severe constriction with a higher sensitivity (96.4%) and specifi city (98.2%) than the conventional MRI.

Conclusion. The axial loaded MRI demonstrated a significant reduction in the dural sac size and signifi cant correlations of the dural sac diameters with the upright myelogram. Furthermore, the axial loaded MRI had higher sensitivity and specifi city than the conventional MRI for detecting the severe constriction observed in the myelogram. Therefore, the axial loaded MRI can be used to represent positional changes of the dural sac size detected by the upright myelography in patients with LSCS.

Multimodality Treatment of Conus Medullaris Arteriovenous Malformations

Neurosurgery 71:100–108, 2012 DOI: 10.1227/NEU.0b013e318256c042

Conus medullaris arteriovenous malformations (AVMs) are rare, challenging spinal vascular lesions that cause progressive debilitating myeloradiculopathy. Only sporadic reports of conus AVMs have been published.

OBJECTIVE: To better define the presentation, prognosis, and optimal treatment of these lesions, we present the first case series of conus AVMs, reflecting over 2 decades of experience with a multimodality endovascular and surgical approach.

METHODS: We retrospectively reviewed the charts of 16 patients with a conus AVM evaluated at our institution from 1989 to 2010. For each patient, the following clinical data were collected: age, sex, symptoms, angiographic findings, type of treatment, complications, degree of angiographic obliteration, recurrence at follow-up, and need for re-treatment. Ambulatory status, Frankel Grade, motor function, and bladder/bowel function were assessed before treatment, at discharge, and at last follow-up.

RESULTS: All 16 patients were treated. Eight (50%) patients underwent embolization followed by microsurgical resection, and 8 (50%) underwent microsurgical resection only. The rate of complete angiographic obliteration was 88%. At last follow-up (mean, 70 months), 43% of patients neurologically improved, 43% were stable, and 14% worsened in comparison with before treatment. During follow-up, 3 recurrences were detected, including the only 2 instances of long-term neurological decline. In the absence of recurrence, all patients ambulatory before treatment remained ambulatory at follow-up, whereas 75% of the initially nonambulatory patients regained the ability to walk.

CONCLUSION: Although conus AVMs are challenging to treat, excellent long-term outcomes are possible with a multimodality approach. Recurrence is associated with long-term neurological decline and calls for close follow-up.

Giant Invasive Spinal Schwannoma: Its Clinical Features and Surgical Management

Neurosurgery 71:58–67, 2012 DOI: 10.1227/NEU.0b013e31824f4f96

Giant invasive spinal schwannoma (GISS) is defined as a lesion that extends over . 2 vertebral levels, erodes vertebral bodies, and extends posteriorly and laterally into the myofascial planes. Because of its rarity, few reports have been issued.

OBJECTIVE: To analyze the clinical features and outcomes of GISS and to discuss surgical strategies.

METHODS: We analyzed the medical records, pathological findings, and radiographic studies of patients with GISS.

RESULTS: Fourteen patients with GISS were surgically treated between 2002 and 2007. Five lesions were in the sacral region, 4 in the lumbosacral, 2 in the thoracolumbar, and 1 each in the cervical, cervicothoracic, and thoracic regions. Gross total resection was performed in 11 of the 14 patients. Satisfactory decompression was performed in all patients for neural compression. Postoperatively, all patients showed relief of pre- operative pain and paresthesia. The growth potential with the Ki-67 index was . 2% in 6 patients, and 4 of them experienced tumor regrowth or recurrence. All patients were followed up for at least 24 months. Final follow-up magnetic resonance images showed asymptomatic small tumor recurrence on the sacrum in 2 patients. Two patients required spinal stabilization. No instability was found on follow-up.

CONCLUSION: Total resection is the treatment of choice for patients with GISS and provides functional improvements, low permanent morbidity, and a low rate of recurrence. Total resection of the intraspinal portion and regular follow-up with con- sideration of the Ki-67 index is recommended when total resection is not achieved.

 

Motion Preservation and Clinical Outcome of Porous Coated Motion Cervical Disk Arthroplasty

Neurosurgery 71:30–37, 2012 DOI: 10.1227/NEU.0b013e31824e512e

Artificial cervical disk replacements are commonly used to treat radiculomyelopathy caused by degenerative disk disease. However, long-term disk mobility and an effect on adjacent segment disease have yet to be demonstrated. We report improvements in clinical outcome after disk replacement but also demonstrate potential limitations.

OBJECTIVE: To review clinical and radiological outcomes after diskectomy and disk replacement with the Porous Coated Motion (PCM) artificial cervical disk.

METHODS: A retrospective review was done of consecutive patients who underwent 1- or 2-level PCM disk replacements. The following criteria were studied: arm pain, neck pain, Neck Disability Index and Short Form-36 questionnaires, and flexion-extension radiographs up to 2 years after surgery.

RESULTS: Eighty PCM artificial disks were implanted in 53 patients. Only 17 disks (21%) maintained physiological movement, and complete fusion was seen in 18.8%. One disk replacement was revised because of anterior displacement. There were no complications of infection, cerebrospinal fluid leak, dysphagia, or hoarse voice. Arm and neck pain improved significantly after diskectomy, but Neck Disability Index questionnaires demonstrated a slight improvement that was not sustained by 2 years. Short Form-36 scores demonstrated a trend toward better outcome with time, but it was significant only for the mental domain.

CONCLUSION: Clinical improvement was seen after PCM disk replacement, but adequate range of movement was sustained in only 21% of disk replacements over time. Unclear long-term results of this and other disk replacements suggest caution in adopting these new devices as the gold standard.

Failure of Percutaneous Remodeling of the Ligamentum Flavum and Lamina for Neurogenic Claudication

Neurosurgery 71:86–92, 2012 DOI: 10.1227/NEU.0b013e31825356f5

Percutaneous remodeling of the ligamentum flavum and lamina (PRLL), commercially known as minimally invasive lumbar decompression (mild technique), relies on fluoroscopy and epidural contrast to direct surgical instruments via a 6-mm cannula.

OBJECTIVE: To evaluate the safety and efficacy of PRLL and present, to our knowledge, the first reported imaging findings after PRLL.

METHODS: We performed a prospective study of PRLL for neurogenic claudication. Primary outcomes were Oswestry Disability Index, Short-Form 12 version 2.0 health survey, and visual analog scale for pain at 26 weeks. Analgesic use was also assessed. Postoperative magnetic resonance imaging was performed at 12 weeks. Long-term failure, defined as the poststudy need for secondary surgery, was assessed up to 18 months.

RESULTS: Ten subjects with an average age of 64 years (range, 41-81 years) were treated between September 2008 and January 2009. There were no major adverse events. Mean postoperative visual analog scale score remained significantly reduced throughout 26 weeks (P =.015, analysis of variance). Mean postoperative Oswestry Disability Index was also improved by 1 week and remained significant throughout 26 weeks (P = .024; analysis of variance). However, there was a trend toward increased reliance on narcotic type medications postoperatively. Imaging studies did not show significant decompression of the spinal canal in any patient. In the poststudy period, recurrent claudication requiring laminectomy developed in 6 patients (60%).

CONCLUSION: Throughout 26 weeks, pain and disability scores were decreased; however, PRLL did not improve the degree of stenosis on imaging studies. Although PRLL appears to be safe in this small cohort of patients, poststudy outcomes indicate that the failure rate is unacceptably high.

 

Anterior Cervical Reconstruction With Pedicle Screws After a 4-Level Corpectomy

Spine 2012 ; 37 : E927 – E930

Anterior reconstruction after multilevel corpectomy is a challenging technique, and there are many reports on its complications. Graft dislodgement is one of the major complications after long cervical fusion. The main cause of failure seems to be a lack of stability in the conventional reconstruction technique. However, pedicle screws for posterior cervical reconstruction show remarkable stability. We describe a new technique of anterior cervical reconstruction with pedicle screws and fibular strut grafting.

Methods. Seven patients with multilevel cervical myelopathy were treated with this new reconstruction technique after a 4-level corpectomy. We describe this new technique and review the patients’ clinical history, results of radiographical imaging, and outcomes. Clinical outcomes were assessed preoperatively and at 3 months postoperatively. Postoperative radiographs were assessed 3 months and 6 months postoperatively.

Results. The mean operative time was 182 minutes and the mean blood loss was 271 mL. The average Japanese Orthopaedic Association score for cervical myelopathy improved from 11.5 points preoperatively to 14.5 points 3 months postoperatively. No patients experienced major complications, such as neurological deterioration, infection, or massive blood loss. There was no case of reconstruction failure, graft dislodgement, migration, or screw displacement.

Conclusion. To our knowledge, this is the first description of an anterior cervical reconstruction approach, using pedicle screws and fibular strut grafting after a 4-level corpectomy. It is likely that this technique will result in better clinical outcomes with fewer complications in the treatment of patients with multilevel cervical myelopathy.

Differences between 1- and 2-level cervical arthroplasty

J Neurosurg Spine 16:594–600, 2012. (http://thejns.org/doi/abs/10.3171/2012.2.SPINE111066)

The most currently accepted indication for cervical arthroplasty is 1- or 2-level degenerative disc disease (DDD) refractory to medical treatment. However, the randomized and controlled clinical trials by the US FDA investigational device exemption studies only compared cervical arthroplasty with anterior cervical discectomy and fusion for 1-level disease. Theoretically, 2-level cervical spondylosis usually implicates more advanced degeneration, whereas the 1-level DDD can be caused by merely a soft-disc herniation. This study aimed to investigate the differences between 1- and 2-level cervical arthroplasty.

Methods. The authors analyzed data obtained in 87 consecutive patients who underwent 1- or 2-level cervical arthroplasty with Bryan disc. The patients were divided into the 1-level and the 2-level treatment groups. Clinical outcomes were measured using the visual analog scale (VAS) for the neck and arm pain and the Neck Disability Index (NDI), with a minimum follow-up of 30 months. Radiographic outcomes were evaluated on both radiographs and CT scans.

Results. The study analyzed 98 levels of Bryan cervical arthroplasty in 70 patients (80.5%) who completed the evaluations in a mean follow-up period of 46.21 ± 9.85 months. There were 22 females (31.4%) and 48 males (68.6%), whose mean age was 46.57 ± 10.07 years at the time of surgery. The 1-level group had 42 patients (60.0%), while the 2-level group had 28 patients (40.0%). Patients in the 1-level group were younger than those in the 2-level group (mean 45.00 vs 48.93 years, p = 0.111 [not significant]). Proportional sex compositions and perioperative prescription of nonsteroidal antiinflammatory drugs were also similar in both groups (p = 0.227 and p = 1.000). The 2-level group had significantly greater EBL during surgery than the 1-level group (220.80 vs 111.89 ml, p = 0.024). Heterotopic ossification was identified more frequently in the 2-level group than the 1-level group (75.0% vs 40.5%, p = 0.009). Although most of the artificial discs remained mobile during the follow up, the 2-level group had fewer mobile discs (100% and 85.7%, p = 0.022) than the 1-level group. However, in both groups, the clinical outcomes measured by VAS for neck pain, VAS for arm pain, and NDI all significantly improved after surgery compared with that preoperatively, and there were no significant differences between the groups at any point of evaluation (that is, at 3, 6, 12, and 24 months after surgery).

Conclusions. Clinical outcomes of 1- and 2-level cervical arthroplasty were similar at 46 months after surgery, and patients in both groups had significantly improved compared with preoperative status. However, there was a significantly higher rate of heterotopic ossification formation and less mobility of the Bryan disc in patients who underwent 2-level arthroplasty. Although mobility to date has been maintained in the vast majority (94.3%) of patients, the long-term effects of heterotopic ossification warrant further investigation.

Direct Lateral Approach to Pathology at the Craniocervical Junction

Neurosurgery 70[ONS Suppl 2]:ons202–ons208, 2012 DOI: 10.1227/NEU.0b013e31824042e6

Approaches to the foramen magnum and upper cervical spine traditionally include the posterior midline, far lateral, and endoscopic endonasal approaches. The far lateral approach is a well-established technique for the removal of pathology ventrolateral to the brainstem and the craniocervical junction, but it may be too extensive for lesions limited to areas far from the midline.

OBJECTIVE: To present an alternative to the commonly used approaches to the foramen magnum and upper cervical.

METHODS: We used an approach directly overlying ventral or lateral pathology.

RESULTS: Two cases are presented in which the direct lateral approach followed by an occipitocervical fusion was successfully performed.

CONCLUSION: This approach can be considered for patients in whom a ventral decompression is necessary but an endoscopic endonasal approach is undesirable or when a ventral, lateral, and ventrolateral resection of tumor, pannus, or infection is required.

Complications associated with the surgical treatment of cervical spondylotic myelopathy

J Neurosurg Spine 16:425–432, 2012. (http://thejns.org/doi/abs/10.3171/ 2012.1.SPINE11467) 

Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM.

Methods. Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors.

Results. The study enrolled 302 patients (mean age 57 years, range 29–86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002–1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002–1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015–1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626–17.256, p = 0.006).

Conclusions. For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.

Morbidity and Mortality of C2 Fractures in the Elderly- Surgery and Conservative Treatment

Neurosurgery 70:1055–1059, 2012 DOI: 10.1227/NEU.0b013e3182446742

Closed C2 fractures commonly occur after falls or other trauma in the elderly and are associated with significant morbidity and mortality. Controversy exists as to best treatment practices for these patients.

OBJECTIVE: To compare outcomes for elderly patients with closed C2 fractures by treatment modality.

METHODS: We retrospectively reviewed 28 surgically and 28 nonsurgically treated cases of closed C2 fractures without spinal cord injury in patients aged 65 years of age or older treated at Stanford Hospital between January 2000 and July 2010. Comorbidities, fracture characteristics, and treatment details were recorded; primary outcomes were 30-day mortality and complication rates; secondary outcomes were length of hospital stay and long-term survival.

RESULTS: Surgically treated patients tended to have more severe fractures with larger displacement. Charlson comorbidity scores were similar in both groups. Thirty-day mortality was 3.6% in the surgical group and 7.1% in the nonsurgical group, and the 30-day complication rates were 17.9% and 25.0%, respectively; these differences were not statistically significant. Surgical patients had significantly longer lengths of hospital stay than nonsurgical patients (11.8 days vs 4.4 days). Long-term median survival was not significantly different between groups.

CONCLUSION: The 30-day mortality and complication rates in surgically and nonsurgically treated patients were comparable. Elderly patients faced relatively high morbidity and mortality regardless of treatment modality; thus, age alone does not appear to be a contraindication to surgical fixation of C2 fractures.

Long-Term Surgical Outcomes of Spinal Meningiomas

Spine 2012 ; 37 : E617 – E623 

Although previous studies have demonstrated favorable surgical outcomes for spinal meningioma, with a low incidence of tumor recurrence, few have examined longterm surgical outcomes.

Methods. The influence of patient age, surgical margin status (Simpson grade), tumor location, and histological subtype on tumor recurrence were examined retrospectively. In addition, the resected dura mater from Simpson grade I cases was examined for invasive tumor cells and compared with the presence or absence of a dural tail sign on magnetic resonance image.

Results. Complete resection (Simpson grades I and II) was performed in 62 patients. Among them, the tumor recurrence rate was 9.7%, all in patients who underwent grade II resection for ventral spinal lesions. The mean duration to reoperation in these patients was 12.2 ± 5.2 years. Of the 6 patients who underwent incomplete resection (Simpson grade III/IV), all required reoperation for tumor recurrence or regrowth, 5 years later on average. Patients younger than 50 years at the initial surgery had a significantly higher recurrence rate than those aged 50 years or older. Histologic examination of 43 dura mater specimens from Simpson grade I-resection patients revealed tumor cell invasion between the inner and outer layers in 15 patients. This invasion was noted in 8 (29%) of 28 patients who were negative for the dural tail sign on magnetic resonance image, and in 7 (47%) of 15 patients who showed a positive dural tail sign. The MIB-1 index reached about 10% for dumbbell-type meningiomas invading the vertebral body; these were associated with repeated recurrence and unfavorable prognosis.

Conclusion. Long-term follow-up after surgery for meningiomas indicated that Simpson grade I resection should be selected whenever practicable when treating younger patients or dumbbelltype meningiomas. Tumors recurred at 12 years, on average, in approximately 30% of patients who underwent grade II resection.

Clinical presentation and prognostic factors of spinal dural arteriovenous fistulas

Neurosurg Focus 32 (5):E17, 2012. (http://thejns.org/doi/abs/10.3171/2012.1.FOCUS11376)

Spinal dural arteriovenous fistulas (AVFs), the most common type of spinal cord vascular malformation, can be a challenge to diagnose and treat promptly. The disorder is rare, and the presenting clinical symptoms and signs are nonspecific and insidious at onset.

Spinal dural AVFs preferentially affect middle-aged men, and patients most commonly present with gait abnormality or lower-extremity weakness and sensory disturbances. Symptoms gradually progress or decline in a stepwise manner and are commonly associated with pain and sphincter disturbances. Surgical or endovascular disconnection of the fistula has a high success rate with a low rate of morbidity. Motor symptoms are most likely to improve after treatment, followed by sensory disturbances, and lastly sphincter disturbances.

Patients with severe neurological deficits at presentation tend to have worse posttreatment functional outcomes than those with mild or moderate pretreatment disability. However, improvement or stabilization of symptoms is seen in the vast majority of treated patients, and thus treatment is justified even in patients with substantial neurological deficits.

The extent of intramedullary spinal cord T2 signal abnormality does not correlate with outcomes and should not be used as a prognostic factor.

Transplantation of mesenchymal stem cells after spinal cord injury

Neurosurgery 70:1238–1247, 2012

DOI: 10.1227/NEU.0b013e31824387f9

Although the transplantation of mesenchymal stem cells (MSCs) after spinal cord injury (SCI) has shown promising results in animals, less is known about the effects of autologous MSCs in human SCI.

OBJECTIVE: To describe the long-term results of 10 patients who underwent intramedullary direct MSCs transplantation into injured spinal cords.

METHODS: Autologous MSCs were harvested from the iliac bone of each patient and expanded by culturing for 4 weeks. MSCs (8 · 106) were directly injected into the spinal cord, and 4 x 10(7) cells were injected into the intradural space of 10 patients with American Spinal Injury Association class A or B injury caused by traumatic cervical SCI. After 4 and 8 weeks, an additional 5 x 10(7) MSCs were injected into each patient through lumbar tapping. Outcome assessments included changes in the motor power grade of the extremities, magnetic resonance imaging, and electrophysiological recordings.

RESULTS: Although 6 of the 10 patients showed motor power improvement of the upper extremities at 6-month follow-up, 3 showed gradual improvement in activities of daily living, and changes on magnetic resonance imaging such as decreases in cavity size and the appearance of fiber-like low signal intensity streaks. They also showed electrophysiological improvement. All 10 patients did not experience any permanent complication associated with MSC transplantation.

CONCLUSION: Three of the 10 patients with SCI who were directly injected with autologous MSCs showed improvement in the motor power of the upper extremities and in activities of daily living, as well as significant magnetic resonance imaging and electrophysiological changes during long-term follow-up.

Cervical Myelopathy After Cervical Total Disc Arthroplasty

Spine 2012 ; 37 : E624 – E628 

This article reports 2 cases in which the patients accepted revision surgery after cervical total disc arthroplasty (CTDA) because of iatrogenic neurological injury.

Summary of Background Data. CTDA has been increasingly investigated to treat cervical degenerative disc disease. However, there are limited reports focused on its complications, especially the neurological complications after the procedure.

Methods. A 52-year-old man underwent total disc arthroplasty for C5–C6, but immediately after surgery, he experienced paralysis of his upper and lower limbs. Radiographical images indicated residual compression to the spinal cord in the level of C5–C6. Another patient, a 60-year-old man, underwent total disc arthroplasty for C4–C5. Afterward, he experienced severe neck pain and paralysis of upper and lower limbs. He was unresponsive to conservative treatments; thus, a laminectomy was performed 3 months later. However, little improvement was observed. Radiographical images indicated kyphosis and spinal cord compression at the level of C4– C5. Furthermore, both cases showed a high signal in the spinal cord by T2-weighted magnetic resonance image, suggestive of spinal cord injuries.

Results. Revision surgeries were performed in both cases. Cervical implants were first removed by the anterior approach, and fusion was then performed after a complete decompression. Motor examination of the patient in case 1 showed grade 3 strength in both of his hands and feet 6 months after revision surgery. In case 2, the patient’s severe neck pain was resolved at the early postoperative stage. Motor examination showed grade 1 strength in both of his hands and feet 3 months after revision surgery.

Conclusion. On the basis of presented cases and other reports, the surgical goals in these patients were prioritized as follows: (1) safe and adequate neurological decompression and (2) establishment and maintenance of cervical sagittal balance. Moreover, a criterion for selecting patients undergoing CTDA needs to be established in order to reduce the occurrence of neurological complications associated with the procedure.

Can Elderly Patients Recover Adequately After Laminoplasty?

Spine 2012 ; 37 : 667 – 671 

This was a prospective clinical comparative study of surgical outcomes for patients with cervical spondylotic myelopathy (CSM).

Objective. The purpose of this study was to compare the surgical outcomes between nonelderly and elderly patients with CSM who underwent laminoplasty.

Summary of Background Data. Age at the time of surgery influences the surgical outcome. We designed a large-scale study of the surgical outcome for CSM from a single operative procedure used exclusively in elderly patients.

Methods. A total of 520 consecutive patients with CSM (331 men; 189 women) who underwent double-door laminoplasty were included. Mean age was 62 years (range, 23–93), and mean duration of disease was 20.1 ± 32.0 months. Average postoperative followup period was 33.3 ± 15.7 months. Patients were divided into 3 groups by age: nonelderly ( < 65 years), young-old (65–74 years), and old-old ( ≥ 75 years). The number of patients in each group was 287, 143, and 90. Pre- and postoperative neurological status was evaluated using the Japanese Orthopaedic Association scoring system for cervical myelopathy (JOA score).

Results. Mean pre- and postoperative JOA scores in nonelderly, young-old, and old-old groups were 11.0 and 14.4, 10.2 and 13.2, and 8.7 and 11.8 points, respectively. The elderly group showed significantly low recovery rates of JOA scores compared with the nonelderly group ( P < 0.0001). However, mean achieved JOA scores (postoperative JOA score − preoperative JOA score) were 3.4, 3.0, and 3.1 in nonelderly, young-old, and old-old groups, respectively, with no significant difference among these groups ( P = 0.17).

Conclusion. Pre- and postoperative JOA scores were low in elderly patients. However, the achieved JOA score was almost similar among the 3 groups. Thus, elderly patients could obtain reasonable recovery after cervical laminoplasty.

Clinical Assessment of Percutaneous Lumbar Pedicle Screw Placement Using the O-Arm Multidimensional Surgical Imaging System

Neurosurgery 70:990–995, 2012 DOI: 10.1227/NEU.0b013e318237a829

Increasing popularity of minimally invasive surgery for lumbar fusion has led to dependence upon intraoperative fluoroscopy for pedicle screw placement, because limited muscle dissection does not expose the bony anatomy necessary for traditional, freehand techniques nor for registration steps in image-guidance techniques. This has raised concerns about cumulative radiation exposure for both surgeon and operating room staff. The recent introduction of the O-arm Multidimensional Surgical Imaging System allows for percutaneous placement of pedicle screws, but there is limited clinical experience with the technique and data examining its accuracy.

OBJECTIVE: We present the first large clinical series of percutaneous screw placement using navigation of O-arm imaging and compare the results with the fluoroscopyguided method.

METHODS: A retrospective review of a 24-month period identified patients undergoing minimally invasive lumbar interbody fusion. The O-arm was introduced in the middle of this period and was used for all subsequent patients. Accuracy of screw placement was assessed by examination of axial computed tomography or O-arm scans.

RESULTS: The fluoroscopy group included 141 screws in 42 patients, and the O-arm group included 205 screws in 52 patients. The perforation rate was 12.8% in the fluoroscopy group and 3% in the O-arm group (P < .001). Single-level O-arm procedures took a mean 200 (153-241) minutes, whereas fluoroscopy took 221 (178-302) minutes (P < .03).

CONCLUSION: Percutaneous pedicle screw placement with the O-arm Multidimensional Intraoperative Imaging System is a safe and effective technique and provided improved overall accuracy and reduced operative time compared with conventional fluoroscopic techniques.

Complications of endoscopic microdiscectomy using the EASYGO! system

Acta Neurochir DOI 10.1007/s00701-012-1321-5.

Microendoscopic discectomy (MED) is emerging as a minimally invasive alternative to conventional microsurgical discectomy (MSD). EASYGO! is a new system for spinal endoscopy that claims smooth transition from MSD to MED, with a reduced learning curve period. The aims of this study were to describe the complications that appeared during the learning curve period of MED and to compare their incidence with the rate and type of complications that occurred during a simultaneous non-randomised series of standard MSDs.

Methods Between July 2009 and December 2010, 138 patients underwent scheduled first-time discectomy in our institution, 37 using an MED approach and 101 by a conventional MSD. A MED learning curve was obtained by plotting every case with its respective operative time. Complications, length of hospital stay, need of further surgery and outcome were prospectively recorded in both groups.

Results The mean operative time was 66 min for the MSD group and 100 min for the MED group, although for the last 14 cases of the latter group the time was reduced. Curvefitting techniques showed that the inverse equation, ƒ(x)= 122.12/x+73.05, had the best correlation between case number and operative time. The learning curve was overcome after the 30th case. Complications occurred in 9.8 % of the MSD group and 8.1 % of the MED group (P=0.49). Average length of hospital stay was 2.36 days for the MED group and 3.36 days for the MSD group (P=0.01). The procedure successfully relieved patient symptoms in 68.63 % of the MSD group and 89.92 % of the MED group. No revision surgery was required in the MED group, but it was necessary in ten patients of the MSD group.

Conclusions Between 25 and 30 cases are needed to reach the learning curve’s asymptote of MED. Even during this initial learning period MED is a safe procedure, with comparable results to those obtained with conventional MSD and with a similar complication rate. The key points for reducing intraoperative complications are an adequate expertise in MSD, a precise selection of initial cases, a proper surgical planning and a careful technique, which are mandatory to avoid unnecessary neurological injury in an otherwise secure surgical approach.

Oxiplex Reduces Leg Pain, Back Pain, and Associated Symptoms After Lumbar Discectomy

SPINE Volume 37, Number 8, pp 631–641

Study Design. Prospective, randomized, blinded clinical trial.

Objective. To evaluate effectiveness of Oxiplex gel for reduction of pain and associated symptoms after lumbar discectomy.

Summary of Background Data. Oxiplex gel (carboxymethylcellulose, polyethylene oxide, and calcium) is used during discectomy to coat the surgical site for reduction of pain and symptoms after lumbar discectomy.

Methods. Patients undergoing single-level lumbar discectomy performed by laminectomy or laminotomy and randomized to receive either surgery plus Oxiplex gel (treatment group) or surgery alone (control group) were assessed 6 months after surgery using (1) a quality of life questionnaire (Lumbar Spine Outcomes Questionnaire [LSOQ]) and (2) clinical evaluations.

Results. There were no statistically significant differences in baseline demographics, surgical procedures, LSOQ scores, and clinical evaluations between treatment (N = 177) and control (N = 175) groups. More gel-treated patients were satisfied with outcome of their surgical treatment than control patients ( P = 0.05). The geltreated group showed greater reductions in pain and symptoms from baseline compared with surgery-only controls. Additional benefits of gel were consistently shown in reduction of leg and back pain at 6 months in the patient population having substantial back  pain at baseline (greater than or equal to the median LSOQ pain score of 63). In that population, there was a statistically signifi cant reduction of leg pain and back pain ( P < 0.01) in the treatment group compared with controls. Fewer patients in the treatment group had abnormal musculoskeletal physical examinations at 6 months compared with controls. There were no cases of cerebrospinal fluid leaks and no differences in laboratory values or vital signs. Patients in the treatment group had less hypoesthesia, paraesthesia, sensory loss, and fewer reoperations during the 6-month follow-up than controls (1 vs . 6).

Conclusion. These data demonstrate improvements in clinical  outcomes resulting from the use of Oxiplex gel in discectomy procedures for treatment of lumbar disc herniation.

Cervical Laminectomy vs Laminoplasty: Is There a Difference in Outcome and Postoperative Pain?

Neurosurgery 70:965–970, 2012 DOI: 10.1227/NEU.0b013e31823cf16b 

Cervical laminoplasty is often used for the decompression of multilevel cervical spondylotic myelopathy without creating spinal instability and kyphosis.

OBJECTIVE: To assess the axial pain, quality of life, sagittal alignment, and extent of decompression after standard cervical laminectomy or laminoplasty. We further evaluate whether the sagittal alignment changes over time after both procedures and whether axial pain depends on sagittal alignment.

METHODS: We reviewed 268 patients with cervical radiculopathy or myelopathy who had undergone standard cervical laminectomy or laminoplasty between January 1999 and January 2009. The clinical outcome was analyzed by visual analog scale for neck pain. The quality of life was analyzed by EQ-5D questionnaire. The degree of deformity and extent of decompression were assessed using the Ishihara index and Pavlov’s ratio, respectively.

RESULTS: Laminoplasty was associated with more neck pain and worse quality of life when 4 or more levels were decompressed compared with the laminectomy group. For operations of 3 or fewer levels, there was no difference. Interestingly, the radiological effectiveness of decompression was greater in the laminoplasty group.

CONCLUSION: Laminoplasty for 4 or more cervical levels was associated with more axial pain and consequently poorer quality of life than laminectomy. There was a similar loss of sagittal alignment in both the laminectomy and laminoplasty groups over time. Our results suggest there is no clear benefit of laminoplasty over laminectomy in patients who do not have spinal instability.