Electrophysiological monitoring during surgery for cervical degenerative myelopathy and radiculopathy

Object

The objective of this systematic review was to use evidence-based medicine to examine the diagnostic and therapeutic utility of intraoperative electrophysiological (EP) monitoring in the surgical treatment of cervical degenerative disease.

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to cervical spine surgery and EP monitoring. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Results

The reliance on changes in EP monitoring as an indication to alter a surgical plan or administer steroids has not been observed to reduce the incidence of neurological injury during routine surgery for cervical spondylotic myelopathy or cervical radiculopathy (Class III). However, there is an absence of study data examining the benefit of altering a surgical plan due to EP changes.

Conclusions

Although the use of EP monitoring may serve as a sensitive means to diagnose potential neurological injury during anterior spinal surgery for cervical spondylotic myelopathy, the practitioner must understand that intraoperative EP worsening is not specific—it may not represent clinical worsening and its recognition does not necessarily prevent neurological injury, nor does it result in improved outcome (Class II). Intraoperative improvement in EP parameters/indices does not appear to forecast outcome with reliability (conflicting Class I data).

Laminectomy and fusion for the treatment of cervical degenerative myelopathy

Object

The objective of this systematic review was to use evidence-based medicine to examine the efficacy of cervical laminectomy and fusion for the treatment of cervical spondylotic myelopathy (CSM).

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical laminectomy, fusion, and CSM. Abstracts were reviewed, after which studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Class I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations which contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer-review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Results

Cervical laminectomy with fusion (arthrodesis) improves functional outcome in patients with CSM and ossification of the posterior longitudinal ligament (OPLL). Functional improvement is similar to laminectomy or laminoplasty for patients with CSM and OPLL. In contrast to laminectomy, cervical laminectomy with fusion it is not associated with late deformity (Class III).

Conclusions

Laminectomy with fusion (arthrodesis) is an effective strategy to improve functional outcome in CSM and OPLL.

Functional outcomes assessment for cervical degenerative disease

Object

The objective of this systematic review was to use evidence-based medicine to identify valid, reliable, and responsive measures of functional outcome after treatment for cervical degenerative disease.

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to functional outcomes. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Results

Myelopathy Disability Index, Japanese Orthopaedic Association scale, 36-Item Short Form Health Survey, and gait analysis were found to be valid and reliable measures (Class II) for assessing cervical spondylotic myelopathy. The Patient-Specific Functional Scale, the North American Spine Society scale, and the Neck Disability Index were found to be reliable, valid, and responsive (Class II) for assessing radiculopathy for nonoperative therapy. The Cervical Spine Outcomes Questionnaire was a reliable and valid method (Class II) to assess operative therapy for cervical radiculopathy.

Conclusions

Several functional outcome measures are available to assess cervical spondylotic myelopathy and cervical radiculopathy.

Techniques for cervical interbody grafting

Object

The objective of this systematic review was to use evidence-based medicine to determine the efficacy of interbody graft techniques.

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical interbody grafting. Abstracts were reviewed and studies that met the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgerons/Congress of Neurological Surgeons.

Results

Autograft bone harvested from the iliac crest, allograft bone from either cadaveric iliac crest or fibula, or titanium cages and rectangular fusion devices, with or without the use of autologous graft or substitute, have been successful in creating arthrodesis after 1- or 2-level anterior cervical discectomy with fusion (Class II). Alternatives to autograft, allograft, or titanium cages include polyetheretherketone cages and carbon fiber cages (Class III). Polyetheretherketone cages have been used successfully with or without hydroxyapatite for anterior cervical discectomy with fusion. Importantly, recombinant human bone morphogenic protein-2 carries a complication rate of up to 23–27% (especially local edema) compared with 3% for a standard approach.

Conclusions

Current evidence does not support the routine use of interbody grafting for cervical arthrodesis. Multiple strategies for interbody grafting have been successful with Class II evidence supporting the use of autograft, allograft, and titanium cages.

Clinical and radiographic comparison of mini-open transforaminal lumbar interbody fusion with open transforaminal lumbar interbody fusion in 42 patients with long-term follow-up

OBJECT

As minimally invasive approaches gain popularity in spine surgery, clinical outcomes and effectiveness of mini-open transforaminal lumbar interbody fusion (TLIF) compared with traditional open TLIF have yet to be established. The authors retrospectively compared the outcomes of patients who underwent mini-open TLIF with those who underwent open TLIF.

METHODS

Between 2003 and 2006, 42 patients underwent TLIF for degenerative disc disease or spondylolisthesis; 21 patients underwent mini-open TLIF and 21 patients underwent open TLIF. The mean age in each group was 53 years, and there was no statistically significant difference in age between the groups (p = 0.98). Data were collected perioperatively. In addition, complications, length of stay (LOS), fusion rate, and modified Prolo Scale (mPS) scores were recorded at routine intervals.

RESULTS

No patient was lost to follow-up. The mean follow-up was 24 months for the mini-open group and 34 months for the open group. The mean estimated blood loss was 194 ml for the mini-open group and 505 ml for the open group (p < 0.01). The mean LOS was 3 days for the mini-open group and 5.5 days for the open group (p < 0.01). The mean mPS score improved from 11 to 19 in the mini-open group and from 10 to 18 in the open group; there was no statistically significant difference in mPS score improvement between the groups (p = 0.19). In the mini-open group there were 2 cases of transient L-5 sensory loss, 1 case of a misplaced screw that required revision, and 1 case of cage migration that required revision. In the open group there was 1 case of radiculitis as well as 1 case of a misplaced screw that required revision. One patient in the mini-open group developed a pseudarthrosis that required reoperation, and all patients in the open group exhibited fusion.

CONCLUSIONS

Mini-open TLIF is a viable alternative to traditional open TLIF with significantly reduced estimated blood loss and LOS. However, the authors found a higher incidence of hardware-associated complications with the mini-open TLIF.

Percutaneous iliac screw placement: description of a new minimally invasive technique

Minimally invasive spinal instrumentation techniques have evolved tremendously over the past decade. Although there have been numerous reports of lumbar instrumentation performed via a percutaneous or minimal incisional route, to date there have been no reports of minimally invasive iliac screw placement. A method was developed for accurate placement of minimally invasive iliac screw placement based on a modification of currently available percutaneous lumbar instrumentation techniques. The method involves fluoroscopically guided insertion of a cannula-based screw system, and this technique was successful applied to treat an L-5 burst fracture with L-4 to iliac spinal stabilization via a minimally invasive approach. This report demonstrates the feasibility of percutaneous iliac screw instrumentation. However, future studies will be needed to validate the safety and efficacy of this approach.

Removal of ossified ligamentum flavum via a minimally invasive surgical approach

Ossified ligamentum flavum (OLF) in the thoracic spine is a rare cause of myelopathy, often presenting with progressive symptomatology over an extended period of time. Surgical decompression via wide laminectomy has been the mainstay of treatment for this symptomatic disease phenomenon, but complications such as kyphotic deformity have developed due to extensive bone removal and release of the posterior tension band. The authors present a case of OLF excised via a minimally invasive microsurgical approach in which an expandable tubular retractor system was used. This approach enables complete decompression of the spinal canal while minimizing nerve, vascular, and musculoskeletal disruption, thus maintaining the native biomechanical disposition of the intact vertebral column.

Mini-open removal of extradural foraminal tumors of the lumbar spine

Spinal extradural foraminal neoplasms are uncommon lesions that are traditionally resected via an open laminectomy and facetectomy approach. In this paper the authors present their mini-open approach for the removal of 3 such tumors. The authors retrospectively reviewed 3 patients with extradural schwannoma who underwent mini-open resection and fusion between June 2006 and July 2007. Clinical data, tumor characteristics, and outcomes were analyzed. All 3 patients underwent successful mini-open treatment of their spinal neoplasms. Postoperative MR imaging demonstrated complete resection in 2 cases and subtotal resection in 1 case. Extradural foraminal neoplasms can be safely and effectively treated with mini-open techniques. Reductions in blood loss, hospitalization, and tissue disruption may be potential benefits of this approach.

Circumferential fusion for cervical kyphotic deformity

Object

The treatment of cervical kyphotic deformity is challenging. Few prior reports have examined combined anterior/posterior correction methods, and fusion rates and standardized outcomes are rarely cited in literature examining these techniques. The authors present their midterm results with cervical kyphosis correction.

Methods

The authors retrospectively reviewed the charts of 30 patients with cervical kyphotic deformity who underwent circumferential spine surgery between 2001 and 2007. The causes of the deformity included chronic fracture in 17 patients, degenerative disease in 10, and tumor in 3. Anterior procedures included discectomies and corpectomies/osteotomies at 1 or more levels with fusion. Posterior operations included decompression and/or osteotomies with lateral mass or pedicle fixation. Preoperative and postoperative Ishihara kyphosis indices, modified Japanese Orthopaedic Association (mJOA) scores, and Nurick grades were analyzed. Arthrodesis was assessed via dynamic radiographs, and CT scans were used to assess fusion in questionable cases.

Results

One patient was lost to follow-up. Two patients died within 1 month of surgery. The follow-up period in the remaining 27 patients ranged from 1 to 6.4 years (mean 2.6 years). Ishihara indices improved from a preoperative mean of −17.7 to a postoperative mean of +11.4. The mean Nurick grades improved from 3.2 preoperatively to 1.3 postoperatively. The mJOA scores improved from a preoperative mean of 10 to 15 postoperatively. All surviving patients who underwent follow-up showed postoperative fusion except 1 patient with renal failure and osteoporosis (95% fusion rate). The overall rate of complications (major and minor) was 33.3%.

Conclusions

In cases of cervical kyphosis, management with decompression, osteotomy, and stabilization from both anterior and posterior approaches can restore cervical lordosis. Furthermore, such surgical techniques can produce measurable improvements in neurological function (as measured with Nurick grades and mJOA scores) and achieve high fusion rates. However, there is a significant rate of complications.

SPINAL DEFORMITY

OBJECTIVE

In this literature review, the authors analyze data from previously published studies that evaluated neutral upright spinal alignment (NUSA) from the occiput to the pelvis in asymptomatic individuals. Based on the data for NUSA in asymptomatic volunteers, a new classification is proposed for spinal deformity.

METHODS

A review of the English literature was conducted to identify studies evaluating NUSA from the occiput to the pelvis in asymptomatic juvenile, adolescent, adult, and geriatric volunteers. From the literature review, 17 angles and displacements were selected to depict neutral upright coronal and axial spinal alignment, and 21 angles and displacements were selected to depict neutral upright sagittal spinal alignment. Pooled estimates of the mean and variance were calculated for the angles and displacements from the articles that met inclusion criteria. A new classification of spinal deformity was then developed based on age-dependent NUSA; spinal abnormality; deformity curve location, pattern, magnitude, and flexibility; and global spinal alignment.

RESULTS

Despite a wide variation in the regional curves from the occiput to the pelvis in asymptomatic volunteers, global spinal alignment is maintained in a narrow range for preservation of horizontal gaze and balance of the spine over the pelvis and femoral heads.

CONCLUSION

A new classification of spinal deformity is proposed that provides a structure for defining deformity of all patient ages and spinal abnormalities.

PEDICLE SUBTRACTION OSTEOTOMY

OBJECTIVE

Pedicle subtraction osteotomy (PSO) is an effective tool for the correction of fixed sagittal plane deformity. However, there is potentially significant perioperative morbidity associated with this technique. We report our perioperative morbidity rate in recently performed PSO cases treated with our present surgical, anesthetic, and monitoring techniques and discuss complication-avoidance strategies.

METHODS

We conducted a retrospective study of 10 patients (mean age, 56 yr; range, 7–77 yr) undergoing thoracolumbar PSO at a single institution in the past 3 years. Two patients underwent PSO at T12, seven patients underwent PSO at L3, and one patient underwent PSO at L2. Eight of the patients had undergone at least one previous spine surgery in the region of the PSO, and nine of the patients had comorbidities that increased their surgical risk stratification. We identified all causes of perioperative morbidity.

RESULTS

We classified perioperative complications into two categories: intraoperative and early postoperative. Intraoperative complications included dural tears in two patients, cardiovascular instability in one patient, and coagulopathy in two patients. Early postoperative complications included neurological deficit (one patient), wound infection (two patients), urinary tract infection (one patient), and delirium (two patients). All patients recovered fully from these complications. There was no mortality in this series.

CONCLUSION

In this series, most patients undergoing PSO had multiple previous spine surgeries and comorbidities. The risk of perioperative morbidity for revision cases undergoing PSO was in excess of 50%. We discuss complication-avoidance strategies.

LONG-SEGMENT SPINAL FIXATION USING PELVIC SCREWS

OBJECTIVE

Long spinal constructs that extend to the sacrum place added stress on sacral screws. To prevent premature loosening of sacral fixation in these cases, the addition of pelvic screw (iliac screw) fixation has gained in popularity. Pelvic screw fixation has also been used in cases where sacral screw fixation is not possible (e.g., in sacral tumors). Pelvic screw fixation is more straightforward than prior pelvic rod fixation techniques (e.g., the Galveston technique). We describe our technique for pelvic screw fixation and review our experience with this technique.

METHODS

Twenty consecutive patients who underwent spinal-pelvic fixation were followed over a 3-year period (2004–2007). The patient population consisted of 11 men and 9 women with an average age of 58.8 years. Indications for spinal-pelvic fixation in this series included kyphoscoliosis, lumbosacral pseudoarthrosis, sacral fractures, lumbosacral spondylolisthesis, sacral tumors, and lumbar osteomyelitic fractures. Radiographic outcomes were assessed using flexion-extension x-rays and computed tomographic scans. Clinical outcomes were assessed using Odom's criteria and modified Prolo scale.

RESULTS

One patient was lost to radiographic follow-up. One patient died after surgery. The mean follow-up for the remaining patients was 13 months (range, 1–21 mo). Odom's outcomes were rated as good to excellent in 11 (58%), fair in 7 (37%), and poor in 1 (5%) (one patient died). Preoperative and postoperative modified Prolo scores were 10.4 and 12.9, respectively (mean improvement, 2.5). Radiographic fusion across the lumbosacral junction was obtained in 16 (89%) of the 18 patients with follow-up. One patient required revision of a pelvic screw. There was one infection requiring explantation of hardware.

CONCLUSION

Pelvic screw fixation is a safe and effective technique that provides added structural support to S1 screws in long-segment spinal fusions. Furthermore, pelvic screw fixation provides a distal point of fixation in cases where sacral screw fixation is not possible. The use of polyaxial screws and connectors makes this technique easier than Galveston rod fixation of the pelvis.

CLASSIFICATION SYSTEMS FOR ADOLESCENT AND ADULT SCOLIOSIS

OBJECTIVE

To review current classification systems for adolescent and adult scoliosis.

METHODS

The literature was reviewed in reference to scoliosis classification systems for adolescent and adult scoliosis.

RESULTS

There are multiple classification systems for scoliosis. Classification of scoliosis is dependent on patient age, spinal abnormality, scoliotic curve, and global spinal alignment. To date, classification systems have focused predominantly on adolescent idiopathic scoliosis or adult/degenerative scoliosis; a single classification system evaluating scoliotic deformities of different ages and spinal abnormalities has not been identified.

CONCLUSION

The importance of scoliosis classification schemes lies in their ability to standardize communication among health care providers. With regard to the classification of adolescent scoliosis, the Lenke system has addressed many of the significant limitations of the King system and is now the standard classification scheme. Classification schemes for adult scoliosis have been reported only recently, and each offers specific advantages (the simple pathogenesis-based system of Aebi, the strong clinical relevance of the Schwab system, and the richly descriptive Scoliosis Research Society system). This article highlights the salient features of currently used scoliosis classification systems.

The Mini-Open transpedicular thoracic discectomy: surgical technique and assessment

Object

Thoracic disc herniations can be surgically treated with a number of different techniques and approaches. However, surgical outcomes comparing the various techniques are rarely reported in the literature. The authors describe a minimally invasive technique to approach thoracic disc herniations via a transpedicular route with the use of tubular retractors and microscope visualization. This technique provides a safe method to identify the thoracic disc space and perform a decompression with minimal paraspinal soft tissue disruption. The authors compare the results of this approach with clinical results after open transpedicular discectomy.

Methods

The authors performed a retrospective cohort study comparing results in 11 patients with symptomatic thoracic disc herniations treated with either open posterolateral (4 patients) or mini-open transpedicular discectomy (7 patients). Hospital stay, blood loss, modified Prolo score, and Frankel score were used as outcome variables.

Results

Patients who underwent mini-open transpedicular discectomy had less blood loss and showed greater improvement in modified Prolo scores (p = 0.024 and p = 0.05, respectively) than those who underwent open transpedicular discectomy at the time of early follow-up within 1 year of surgery. However, at an average of 18 months of follow-up, the Prolo score difference between the 2 surgical groups was not statistically significant. There were no major or minor surgical complications in the patients who received the minimally invasive technique.

Conclusions

The mini-open transpedicular discectomy for thoracic disc herniations results in better modified Prolo scores at early postoperative intervals and less blood loss during surgery than open posterolateral discectomy. The authors' technique is described in detail and an intraoperative video is provided.

Minimally invasive approach to extraforaminal disc herniations at the lumbosacral junction using an operating microscope: case series and review of the literature

Surgical access to extraforaminal lumbar disc herniations is complicated due to the unique anatomical constraints of the region. Minimizing complications during microdiscectomies at the level of L5–S1 in particular remains a challenge. The authors report on a small series of patients and provide a video presentation of a minimally invasive approach to L5–S1 extraforaminal lumbar disc herniations utilizing a tubular retractor with microscopic visualization.

The safety and efficacy of anterior cervical discectomy and fusion with polyetheretherketone spacer and recombinant human bone morphogenetic protein-2: a review of 200 patients

OBJECT

The goal in this study was to demonstrate the safety and efficacy of anterior cervical discectomy and fusion ([ACDF]; single- or multilevel procedure) performed using titanium plates and polyetheretherketone (PEEK) spacers filled with recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated in a type I collagen sponge to achieve fusion.

METHODS

The authors retrospectively reviewed 200 patients who underwent a single- or multilevel ACDF with titanium plate fixation and PEEK spacer filled with a collagen sponge impregnated with low-dose rhBMP-2. Clinical outcomes were assessed using pre- and postoperative Nurick grades and the Odom criteria. Radiographic outcomes were assessed using dynamic radiographs and computed tomography (CT) scans.

RESULTS

The follow-up period ranged from 8 to 36 months (mean 16.7 months). A single-level ACDF was performed in 96 patients, 2-level ACDF in 62 patients, 3-level ACDF in 36 patients, and 4-level ACDF in 6 patients. Long-term follow-up was available for 193 patients. The Odom outcomes were rated as good to excellent in 165 patients (85%), fair in 24 (12.4%), and poor in 4 (2%). Among patients with myelopathy, Nurick grades improved from a preoperative mean of 1.42 to a postoperative mean of 0.26. All patients (100%) achieved solid radiographic fusion on dynamic radiographs and CT scans. Fourteen patients (7%) in this series experienced clinically significant dysphagia, and 4 (2%) required repeated operation for hematoma or seroma.

CONCLUSIONS

An ACDF performed using a PEEK spacer filled with rhBMP-2 leads to good to excellent clinical outcomes and solid fusion, even in multilevel cases and in patients who are smokers. The incidence of symptomatic dysphagia may be decreased with a lower dose of rhBMP-2 that is placed only within the PEEK spacer.

Nucleus replacement technologies

Nucleus replacement offers a less invasive alternative to traditional fusion or total disc replacement techniques in the treatment of symptomatic lumbar degenerative disc disease (DDD). The authors discuss the classification of nucleus replacement devices as well as their potential indications. The authors review the history and evolution of nucleus replacement devices emphasizing several that are actively in US Investigational Device Exemption pilot feasibility trials. Nucleus replacement devices can be functionally categorized as elastomeric and mechanical. A classification scheme is discussed. Nucleus replacement remains investigational, but early clinical results have been encouraging. Further clinical investigation with well-designed prospective, randomized pivotal trials is needed to determine the efficacy of nucleus replacement in the treatment of lumbar DDD, as well as its ideal indications.

A treatment algorithm for the management of cervical spine fractures and deformity in patients with ankylosing spondylitis

Object

Patients with ankylosing spondylitis (AS) who present with cervical spine fractures represent a unique challenge to spine surgeons. These injuries often result in neurological deficits that necessitate early and aggressive surgical management with posterior and/or anterior fixation. The authors introduce a clinical problem-solving algorithm to assist in the surgical management of instability and deformity in this exigent patient population.

Methods

Thirteen patients with AS and fractures of the cervical spine were radiographically evaluated to determine if spinal realignment was obtainable with cervical manipulation or traction. Seven patients had flexible deformities that were stabilized with either anterior or posterior fixation only, and 6 patients had fixed deformities and required circumferential anterior–posterior instrumentation. All patients were observed for neurological outcome, radiographic evidence of bone fusion, and complications.

Results

With the use of the authors' treatment algorithm, all patients were able to achieve satisfactory spinal realignment and bone fusion; 92% of patients achieved postoperative stability or improvement in Nurick and modified Japanese Orthopaedic Association scale scores. One patient experienced neurological deterioration following surgery, and 1 patient died at an acute rehabilitative facility following discharge.

Conclusions

Patients with AS are highly susceptible to extensive neurological injury and spinal deformity after sustaining cervical fractures from even minor traumatic forces. These injuries are uniquely complex in nature and require considerable scrutiny and aggressive surgical management to optimize spinal stability and functional outcomes. The authors' clinical problem-solving algorithm will assist spine surgeons in providing optimal care in this difficult population.

Delayed-onset neurological deficit following correction of severe thoracic kyphotic deformity

✓There are many potential risks associated with spinal deformity correction procedures including transient and/or permanent neurological deficits. Typically, neurological deficits caused by the surgical correction of spinal kyphosis occur acutely during surgery or immediately after surgery. Delayed postoperative neurological deficits are extremely rare.

The authors report a case of delayed neurological deficit that occurred 48 hours after surgical correction of thoracic hyperkyphosis. An 18-year-old man with myotonic dystrophy presented with a 110° T7–L1 kyphosis. The patient underwent an uneventful two-stage correction procedure of the hyperkyphotic deformity. First, anterior discectomies and fusion were performed from T-7 to L-1 using rib autograft, and all segmental vessels were preserved. Subsequently, on the same day, the patient underwent posterior Smith–Petersen osteotomies and T7–L2 pedicle screw fixation. Intact somatosensory and motor evoked potentials were maintained throughout both operations. Postoperatively, he remained neurologically intact without sequelae for nearly 48 hours. On postoperative Day 2, the patient developed delayed monoplegia of the left leg and sensory level loss below T-10.

Medical management enabled complete reversal of the patient's monoplegia and sensory loss. At 2-year follow-up, the patient had no adverse neurological sequelae.

In this case, a delayed postoperative neurological deficit occurred following spinal hyperkyphosis correction. The authors discuss the possible etiological mechanisms behind this complication and suggest strategies for its management.

Combined ventral and dorsal surgery for myelopathy and myeloradiculopathy

The past decade has witnessed significant advances in the surgical treatment of cervical myelopathy and myeloradiculopathy. In this article, we discuss in detail the indications for combined ventral and dorsal surgery for the treatment of cervical myelopathy and myeloradiculopathy. In addition, the advances in surgical technique and instrumentation in cervical spine surgery are explored. Finally, complication avoidance and management strategies are discussed. Combined ventral and dorsal decompression, reconstruction, and instrumentation procedures are viable options in the treatment of a select group of patients with complex cervical myelopathy or myeloradiculopathy.

Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial

OBJECT

The authors report the results of a prospective randomized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion (ACDF) in patients treated for symptomatic single-level cervical degenerative disc disease (DDD).

METHODS

Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly assigned to one of two treatment groups: 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System (Medtronic Sofamor Danek); 265 patients in the control group underwent decompressive ACDF. Eighty percent of the arthroplasty-treated patients (223 of 276) and 75% of the control patients (198 of 265) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery. Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group. The arthroplasty group also had a statistically significant higher rate of neurological success (p = 0.005) as well as a lower rate of secondary revision surgeries (p = 0.0277) and supplemental fixation (p = 0.0031). The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months, as was relief of neck pain. The patients in the investigational group returned to work 16 days sooner than those in the control group, and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well (p = 0.0492, log-rank test). The cervical disc implant maintained segmental sagittal angular motion averaging more than 7 degrees. In the investigational group, there were no cases of implant failure or migration.

CONCLUSIONS

The PRESTIGE ST Cervical Disc System maintained physiological segmental motion at 24 months after implantation and was associated with improved neurological success, improved clinical outcomes, and a reduced rate of secondary surgeries compared with ACDF.

CERVICAL ARTHROPLASTY WITH THE PRESTIGE LP CERVICAL DISC

The technique for anterior cervical arthroplasty using the PRESTIGE LP (Medtronic Sofamor Danek, Memphis, TN) cervical disc is illustrated. Surgical positioning and the operative approach are demonstrated. Our methods of retractor placement and surgical exposure are discussed. The technique used for decompression and endplate preparation is presented in detail. Optimal arthroplasty device positioning is demonstrated. The surgical pearls and pitfalls of anterior cervical arthroplasty are highlighted.

THE DECISION-MAKING PROCESS

THE DECISION WHETHER to use allograft or autograft in ventral cervical fusions has been widely discussed. The literature includes several prospective randomized trials. Extensive clinical evidence indicates that autograft use results in increased arthrodesis rates and less graft collapse. However, autograft harvest has a substantial morbidity rate. Allografts avoid the morbidity associated with autograft harvest but result in decreased arthrodesis rates and increased graft collapse rates. The decreased arthrodesis rate associated with allografts becomes more significant in multilevel surgery and in patients who smoke. The introduction and use of ventral cervical plates have made allograft use more attractive by increasing arthrodesis rates and decreasing graft collapse.

Infected vertebroplasty requiring 360 degrees spinal reconstruction: long-term follow-up review. Report of two cases

Transpedicular vertebroplasty has been established as a safe and effective treatment of thoracic and lumbar compression fractures. Complications are rare, and infectious complications requiring surgical management have only been reported once in the literature. The authors present two cases of infectious complications requiring surgical management. They emphasize that systemic infection is a contraindication to the performance of vertebroplasty. The serious nature of these infections, their surgical management, and strategies for avoiding them are discussed.

Cervicothoracic Kyphosis

Cervicothoracic kyphotic deformity may inhibit horizontal gaze function, impede activities of daily living, and induce disabling pain. Eventually, some patients develop a chin-on-chest deformity that limits their ability to eat and drink; in the end stage, a few patients also may have difficulty breathing. Progressive kyphosis can stretch the spinal cord leading to myelopathy with progressive lower extremity spasticity and weakness. Indications for surgery include myelopathy, pain, dysphagia or dyspnea owing to kyphosis, and difficulty maintaining a functional horizontal gaze. Patients with unstable cervicothoracic fractures also require surgical fixation. For these patients, surgical goals include deformity correction with restoration of an acceptable forward gaze, re-establishment of sagittal balance, decompression of the spinal cord (if myelopathic), and stable fixation.

The mini-open transforaminal lumbar interbody fusion

The mini-open approach for transforaminal lumbar interbody fusion is described in detail. Operating room setup and surgical positioning are demonstrated. Our methods of retractor placement and techniques for optimal surgical exposure are discussed. The surgical technique used for decompression and fusion is presented in detail. The surgical pearls and pitfalls of the mini-open TLIF are described and illustrated.

Recurrent subdural hematoma caused by cerebrospinal fluid leakage. Case report

The authors report a case of a recurrent subdural hematoma (SDH) that was caused by a persistent cerebrospinal fluid (CSF) leak from an L1-2 fistula. A 34-year-old man experienced severe headaches due to SDH, and he underwent aspiration of subdural fluid four times due to recurrent collections. Further evaluation with computerized tomography (CT) myelography demonstrated extradural extravasation of contrast through an L1-2 fistula. The patient underwent an L1-2 laminectomy; a small dural defect with CSF leakage at the left nerve root sleeve was found and was repaired. Following the repair, the patient had no further recurrence of SDH. Recurrent SDH, caused by spontaneous CSF leakage through a lumbar CSF fistula, is extremely rare. In cases of recurrent SDH, radiographic workup with spinal CT myelography should be considered.

Current treatment strategies for the painful lumbar motion segment: posterolateral fusion versus interbody fusion

STUDY DESIGN

Review of the literature.

OBJECTIVES

We discuss the indications and contraindications for posterolateral lumbar fusion and posterior approaches to lumbar interbody fusion. We also review the advances in minimal access surgical techniques, graft materials, and osteobiologics.

SUMMARY OF BACKGROUND DATA

Previously published data and our own surgical experience form the basis of this report.

METHODS

A Pub Med online internet search for the keywords was performed. The pertinent articles were then cited.

RESULTS

Posterior interbody fusion techniques have theoretical and demonstrable advantages over posterolateral fusion, but the former is also associated with greater morbidity. There are several approaches one may use to perform posterior interbody fusion, as well as multiple minimally invasive techniques and interbody spacer graft options. Bone morphogenetic protein offers an attractive alternative for achieving fusion.

CONCLUSION

Fusion of painful motion segments is widely used to treat patients with degenerative low back pain. Successful arthrodesis may be achieved using either posterolateral fusion with pedicle screw fixation or posterior interbody fusion, depending on the patient's situation. These techniques may be accomplished with a variety of minimal access strategies and various graft and spacer technologies. The modern spine surgeon should be proficient in using all these options to treat the painful lumbar motion segment.

Anterior cervical discectomy and fusion involving a polyetheretherketone spacer and bone morphogenetic protein

OBJECT

The authors reviewed clinical and radiographic outcomes in patients who had undergone anterior cervical discectomy and fusion (ACDF) involving the placement of polyetheretherketone (PEEK) spacers filled with recombinant human bone morphogenetic protein (rhBMP)-2.

METHODS

Data obtained in 24 cases were retrospectively evaluated. The follow-up period ranged from 12 to 16 months (mean 13 months). Fifteen patients presented with radiculopathy, eight with myeloradiculopathy, and one with quadriparesis. Single-level ACDF was performed in 12 patients, two-level ACDF in nine, and three-level ACDF in three. Clinical outcomes were assessed using Odom criteria, and fusion was assessed by examining flexion-extension radiographs and computerized tomography scans in cases in which arthrodesis was questionable. Follow-up data were available for 23 patients. One patient died of medical complications unrelated to surgery 4 weeks after ACDF. Clinical outcomes were rated as good/excellent in 22 patients (95%) and fair in one (5%). Solid radiographically documented fusion, with evidence of solid bridging bone and no instability on flexion-extension x-ray films, was present in all cases. Complications included transient recurrent laryngeal nerve injury in one case, transient C-5 paresis in one, cerebrospinal fluid leakage in one, and transient dysphagia in two.

CONCLUSIONS

Analysis of the results indicated that ACDF involving an rhBMP-2-filled PEEK spacer leads to good clinical outcomes (by Odum criteria) and solid fusion (even in multilevel cases) while avoiding the complications associated with harvesting iliac crest bone grafts.

Transoral odontoidectomy

The transoral approach for odontoidectomy is described in detail, and the operating room setup and surgical positioning are demonstrated. We also discuss our methods of retractor placement and techniques for optimal surgical exposure. The microsurgical technique used for decompression is presented in detail. The surgical pearls and pitfalls of transoral odontoidectomy, learned from a 70-case experience, are described and illustrated.

Minimally Invasive, Endoscopic, Internal Thoracoplasty for the Treatment of Scoliotic Rib Hump Deformity: Technical Note

OBJECTIVE:

Patients with idiopathic scoliosis often have a noticeable rib deformity that frequently persists after corrective surgery. Open thoracoplasty has been the traditional method of reducing rib deformity. Recently, however, video-assisted thoracoscopy (VATS) has been used to perform thoracoplasty. There have been no long-term follow-up studies on VATS thoracoplasty, nor have there been outcome scores to assess the results of thoracoplasty procedures. We present our experience using VATS thoracoplasty with long-term follow-up and propose an outcome grading system for thoracoplasty.

METHODS:

Between 1998 and 2000, four patients (age range, 14–53 yr) underwent VATS thoracoplasty for significant rib hump deformity (mean height, 5 cm; range, 4–6 cm) associated with idiopathic scoliosis. All patients had four rib segments resected during the VATS thoracoplasty procedure. Three of the four patients also underwent anterior thoracic release and discectomy during the procedure.

RESULTS:

Patients were followed for a mean of 40 months after surgery (range, 33–50 mo). There were no intraoperative or postoperative complications. Outcomes were assessed using a patient questionnaire with our new thoracoplasty grading system. All patients were pleased that they had chosen to have VATS internal thoracoplasty. Based on our new grading system, two patients had an excellent outcome and two had a good outcome.

CONCLUSION:

VATS provides an alternative, minimally invasive route to perform thoracoplasty. VATS incisions are much smaller and more cosmetically appealing than open thoracoplasty incisions. Long-term follow-up indicates good to excellent patient outcomes.

Analysis of operative complications in a series of 471 anterior lumbar interbody fusion procedures

STUDY DESIGN

This retrospective review compares the intraoperative and perioperative complications associated with the placement of threaded devices and nonthreaded devices used in anterior lumbar interbody fusions.

OBJECTIVE

Anterior lumbar interbody fusion is a common procedure performed with either a nonthreaded device, such as a femoral ring, or a threaded device, such as with a cage or a bone dowel.

SUMMARY OF BACKGROUND DATA

Many studies have been done detailing the fusion rates and biomechanical properties of both devices. However, few studies have been performed evaluating acute complications between the two device types.

METHODS

A retrospective chart review was performed of 471 consecutive patients who underwent anterior lumbar interbody fusion: 243 with a nonthreaded interbody device and 228 with a threaded interbody device. Operative notes, anesthesia reports, discharge summaries, and follow-up notes were reviewed from 1992 to June 2002. The patients' demographics, diagnosis, number of levels fused, type of device used, length of hospital stay, and acute complications, either intraoperative or perioperative, were collected and analyzed.

RESULTS

Approximately 4.8% of patients with a threaded type interbody device had an intraoperative complication whereas only 0.4% of patients with a nonthreaded type device had an intraoperative complication. There was a significant association between interbody device type (threaded vs. nonthreaded) and occurrence of an intraoperative complication (P = 0.0024).

CONCLUSIONS

Placement of threaded devices, such as cages or bone dowels, was associated with a higher acute complication rate than was the placement of nonthreaded devices during anterior lumbar interbody fusion.

Occipitocervical fixation: long-term results

STUDY DESIGN

The study is a retrospective review of 58 patients who underwent occipitocervical fusion between 1997 and 2001.

OBJECTIVES

Our objective is to study the clinical results after occipitocervical fixation with long-term follow-up and assess factors contributing to clinical success.

METHODS

Data from patient charts, operative notes, physician office notes, and imaging studies were incorporated in the study. Myelopathy was assessed using a Nurick scale for preoperative and postoperative evaluation. Fusion was assessed using cervical plane films with flexion and extension views.

RESULTS

Mean follow-up was 36 months, with all patients having a greater than 1-year follow-up. The most common pathology was congenital cranial settling (41%) followed by trauma (22%) and rheumatoid arthritis (17%). Myelopathy was the most common presentation (62%) followed by pain (28%). A successful fusion occurred in 48 out of 51 patients (94%). Symptoms improved in 86% of patients, whereas 35% improved 1 Nurick grade. Complications occurred in 30% of patients. The cervical wound infection rate was 5%. The rate of adjacent level degeneration was 7%. The mortality rate was 1.7%.

CONCLUSIONS

Occipitocervical instrumentation allows for very high fusion rates without the need for halo vest immobilization. All patients with successful fixation have pain resolution. Myelopathy improves in most patients, whereas one-third of patients demonstrate dramatic improvement.

Atlantoaxial fixation: Overview of all techniques

Over the past century, steady advances have been made in fixating an unstable atlantoaxial complex. Current options for fixation of the atlantoaxial complex include posterior clamps, posterior wiring techniques, C1-C2 transarticular screw fixation, posterior C1 lateral mass screw with C2 pars or pedicle screw fixation, and anterior transoral C1 lateral mass to C2 vertebral body fixation.

The future in the care of the cervical spine: interbody fusion and arthroplasty

✓ In the past 50 years tremendous advances have been made in the treatment of cervical disc disease with cervical fusion. Fusion rates have surpassed 95% after application of anterior cervical implants. Adjacent-segment degeneration, however, has plagued the long-term clinical success of cervical fusion.

Cervical arthroplasty has been introduced to maintain cervical motion and potentially avoid or minimize adjacent-segment degeneration. If cervical arthroplasty is successful, the long-term results of surgery for cervical disc disease may improve; however, there are associated drawbacks that must be overcome. Implant wear, fatigue, and failure have been reported in cases of large-joint arthroplasty, and research is underway to limit these problems in cervical arthroplasty.

In this article the authors trace the evolution of cervical fusion and the new technique of cervical arthroplasty. The nomenclature of cervical arthroplasty will also be introduced.

The future in the care of the cervical spine: interbody fusion and arthroplasty

✓ In the past 50 years tremendous advances have been made in the treatment of cervical disc disease with cervical fusion. Fusion rates have surpassed 95% after application of anterior cervical implants. Adjacent-segment degeneration, however, has plagued the long-term clinical success of cervical fusion.

Cervical arthroplasty has been introduced to maintain cervical motion and potentially avoid or minimize adjacent-segment degeneration. If cervical arthroplasty is successful, the long-term results of surgery for cervical disc disease may improve; however, there are associated drawbacks that must be overcome. Implant wear, fatigue, and failure have been reported in cases of large-joint arthroplasty, and research is underway to limit these problems in cervical arthroplasty.

In this article the authors trace the evolution of cervical fusion and the new technique of cervical arthroplasty. The nomenclature of cervical arthroplasty will also be introduced.

Lumbar interbody fusion: state-of-the-art technical advances. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004

During the past few decades, three techniques have been used to achieve circumferential lumbar interbody fusion (LIF). They include posterior LIF, anterior LIF with supplemental posterior fixation, and transforaminal LIF. In this article, the authors describe the indications and contraindications for the use of interbody fusion. The advantages and disadvantages of each will be discussed in detail. Additionally, strategies for minimally invasive access and options for interbody spacer materials will be discussed.

Contribution of recombinant human bone morphogenetic protein-2 to the rapid creation of interbody fusion when used in transforaminal lumbar interbody fusion: a preliminary report. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004

OBJECT

The authors compared fusion rates in transforaminal lumbar interbody fusion (TLIFs) when using either autograft or bone morphogenetic protein (BMP) placed in the interbody space.

METHODS

Between September 2002 and December 2003, the authors performed 44 TLIF operations. Follow-up data were available for 40 patients. Of the 40 procedures, 19 involved cages filled with iliac crest autograft (Group 1) and 21 involved cages filled with a medium kit of recombinant human (rh) BMP-2 (Group 2). In all Group 2 patients, one BMP sponge was placed anterior to the cage and another was placed within the cage. In 12 of the Group 2 patients, iliac crest autograft was placed posterior to the BMP-filled cage (Group 2A). In the remaining nine Group 2 patients, only local autograft was placed posterior to the BMP-filled cage (Group 2B). Assessment of fusion was performed using dynamic radiography at 3-month intervals. Outcomes were assessed using the Prolo Scale, and iliac crest donor site pain was measured using a Visual Analog Scale (VAS). The mean follow-up period was 9 months (range 3-18 months). In Group 1 patients, one pseudarthrosis was detected. In Group 2 patients, dynamic radiography demonstrated solid fusion in all patients except one in Group 2B. Fifty-eight percent of patients in whom iliac crest autograft was used complained of donor site pain 6 months after surgery (5 of 10 points on the VAS). Symptomatic foraminal bone formation was not observed in any Group 2 patient.

CONCLUSIONS

The use of rhBMP-2 is safe in TLIFs when the sponges are placed away from the dura mater, and BMP promotes a more rapid fusion than iliac crest autograft alone. The use of rhBMP-2 in combination with local autograft is an excellent option for promoting solid fusion with TLIF, and it eliminates the possibility of iliac donor site pain.