Initial Results of Precision Treatment of Postoperative Cerebrospinal Fluid Leak with Ultrasound-Guided Epidural Blood Patch

BACKGROUND

Incidental durotomy, a known complication of spinal surgery, can lead to persistent cerebrospinal fluid leak and pseudomeningocele if unrecognized or incompletely repaired. We describe the use of ultrasound to visualize the site of durotomy, observe the aspiration of the pseudomeningocele, and guide the precise application of an ultrasound-guided epidural blood patch (US-EBP), under direct visualization in real time.

METHODS

A retrospective review was performed to determine demographic, procedural, and outcome characteristics for patients who underwent US-EBP for symptomatic postoperative pseudomeningocele.

RESULTS

Overall, 48 patients who underwent 49 unique episodes of care were included. The average age and body mass index were 60.5 (±12.6) years and 27.8 (±4.50) kg/m², respectively. The most frequent index operation was laminectomy (24.5%), and 36.7% of surgeries were revision operations. Durotomy was intended or recognized in 73.4% of cases, and the median time from surgery to symptom development was 7 (interquartile range 4-16) days. A total of 61 US-EBPs were performed, with 51.0% of patients experiencing resolution of their symptoms after the first US-EBP. An additional 20.4% were successful with multiple US-EBP attempts. Complications occurred in 14.3% of cases, and the median clinical follow-up was 4.3 (interquartile range 2.4-14.5) months.

CONCLUSIONS

This manuscript represents the largest series in the literature describing US-EBP for the treatment of postoperative pseudomeningocele. The success rate suggests that routine utilization of US-guided EBP may allow for targeted treatment of pseudomeningoceles, without the prolonged hospitalization associated with lumbar drains or the risks of general anesthesia and impaired wound healing associated with surgical revision.

Partial Costotransversectomy and Corpectomy for Thoracic Spinal Metastatic Disease: Operative Technique and Nuances: 2-Dimensional Operative Video

We describe the operative approach and management for thoracic metastatic disease in a 78-yr-old man with worsening mechanical lower back and left-sided thoracic radicular pain. Imaging of the thoracic spine revealed an osteolytic T11 mass with destruction of the left T11 pedicle and transverse process. Biopsy confirmed spinal metastasis from the liver. Preoperative angiogram was completed for localization of the artery of Adamkewicz and microparticle embolization of the left T11 intercostal artery. Surgical resection was supplemented with electrophysiological monitoring and neuronavigation. The corpectomy was approached by resecting the medial aspect of the rib, transverse process, and pedicle, which were all invaded with tumor. The left T11 nerve root was isolated and sacrificed to allow for placement of the expandable corpectomy cage and also resulted in sustained relief of the patient's radicular pain. The patient recovered from surgery well, with postoperative improvement of his pain. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation, including angiography, as proper identification of the artery of Adamkewitz can prevent severe neurological deficit from a spinal cord stroke. The patient consented to the procedure.

Biomechanics of transvertebral screw fixation in the thoracic spine: an in vitro study

OBJECTIVE Transvertebral screws provide stability in thoracic spinal fixation surgeries, with their use mainly limited to patients who require a pedicle screw salvage technique. However, the biomechanical impact of transvertebral screws alone, when they are inserted across 2 vertebral bodies, has not been studied. In this study, the authors assessed the stability offered by a transvertebral screw construct for posterior instrumentation and compared its biomechanical performance to that of standard bilateral pedicle screw and rod (PSR) fixation. METHODS Fourteen fresh human cadaveric thoracic spine segments from T-6 to T-11 were divided into 2 groups with similar ages and bone quality. Group 1 received transvertebral screws across 2 levels without rods and subsequently with interconnecting bilateral rods at 3 levels (T8-10). Group 2 received bilateral PSR fixation and were sequentially tested with interconnecting rods at T7-8 and T9-10, at T8-9, and at T8-10. Flexibility tests were performed on intact and instrumented specimens in both groups. Presurgical and postsurgical O-arm 3D images were obtained to verify screw placement. RESULTS The mean range of motion (ROM) per motion segment with transvertebral screws spanning 2 levels compared with the intact condition was 66% of the mean intact ROM during flexion-extension (p = 0.013), 69% during lateral bending (p = 0.015), and 47% during axial rotation (p < 0.001). The mean ROM per motion segment with PSR spanning 2 levels compared with the intact condition was 38% of the mean intact ROM during flexion-extension (p < 0.001), 57% during lateral bending (p = 0.007), and 27% during axial rotation (p < 0.001). Adding bilateral rods to the 3 levels with transvertebral screws decreased the mean ROM per motion segment to 28% of intact ROM during flexion-extension (p < 0.001), 37% during lateral bending (p < 0.001), and 30% during axial rotation (p < 0.001). The mean ROM per motion segment for PSR spanning 3 levels was 21% of intact ROM during flexion-extension (p < 0.001), 33% during lateral bending (p < 0.001), and 22% during axial rotation (p < 0.001). CONCLUSIONS Biomechanically, fixation with a novel technique in the thoracic spine involving transvertebral screws showed restoration of stability to well within the stability provided by PSR fixation.

Redirecting pedicle screws: a revision spinal fusion strategy using three-dimensional image guidance

BACKGROUND

Pedicle screws are a preferred method for spinal fixation because of their three-column support and rigid posterior stabilization. The purpose of this study was to evaluate the outcome of patients requiring pedicle screw redirection, and to describe a technique using cone-beam computed tomography (cbCT).

METHODS

A retrospective review of 30 patients undergoing revision spinal fusion with redirection of pedicle screws was performed. Fifty pedicle screws were redirected in these patients using cbCT-based 3D image guidance. They were graded pre- and post-operatively using an established grading system.

RESULTS

No complications occurred in this study as a result of redirection. No pedicle breach was noted in all of the redirected pedicle screws.

CONCLUSION

Redirection of misplaced pedicle screws using cbCT-based 3D image guidance seems to be safe and accurate in our experience. Further studies are needed to establish its safety, accuracy, fusion rate, and clinical outcome compared with other methods. Copyright © 2016 John Wiley & Sons, Ltd.

Radiographic comparison of cross-sectional lumbar pedicle fill when placing screws with navigation versus free-hand technique

BACKGROUND

Pedicle screws are often used for spinal fixation. Increasing the percentage of pedicle that is filled with the screw presumably yields greater fixation. It has not been shown whether spinal navigation helps surgeons more completely fill their instrumented pedicles.

METHODS

Fifty consecutive patients from each arm (navigated and free-hand) were retrospectively reviewed. The cross-sectional area of each instrumented lumbar pedicle and screw were measured using an automatic area calculation tool. The coronal images and measurements were blinded to the surgeons.

RESULTS

The instrumented pedicles in the navigated patients were significantly more filled by screws than the pedicles in the non-navigated patients (P < 0.001).

CONCLUSION

Obtaining a higher cross-sectional percentage fill of the pedicle with a screw is expected to provide greater spinal fixation in instrumented fusion surgery. This study shows that utilizing spinal navigation helps to more completely fill the pedicles that are being instrumented. Copyright © 2015 John Wiley & Sons, Ltd.

Intraoperative image-guided spinal navigation: technical pitfalls and their avoidance

Spinal instrumentation has made significant advances in the last two decades, with transpedicular constructs now widely used in spinal fixation. Pedicle screw constructs are routinely used in thoracolumbar-instrumented fusions, and in recent years, the cervical spine as well. Three-column fixations with pedicle screws provide the most rigid form of posterior stabilization. Surgical landmarks and fluoroscopy have been used routinely for pedicle screw insertion, but a number of studies reveal inaccuracies in placement using these conventional techniques (ranging from 10% to 50%). The ability to combine 3D imaging with intraoperative navigation systems has improved the accuracy and safety of pedicle screw placement, especially in more complex spinal deformities. However, in the authors' experience with image guidance in more than 1500 cases, several potential pitfalls have been identified while using intraoperative spinal navigation that could lead to suboptimal results. This article summarizes the authors' experience with these various pitfalls using spinal navigation, and gives practical tips on their avoidance and management.

Migration to the ICD-10 coding system: A primer for spine surgeons (Part 1)

Background:

On 1 October 2015, a new federally mandated system goes into effect requiring the replacement of the International Classification of Disease-version 9-Clinical Modification (ICD-9-CM) with ICD-10-CM. These codes are required to be used for reimbursement and to substantiate medical necessity. ICD-10 is composite with as many as 141,000 codes, an increase of 712% when compared to ICD-9.

Methods:

Execution of the ICD-10 system will require significant changes in the clinical administrative and hospital-based practices. Through the transition, diminished productivity and practice revenue can be anticipated, the impacts of which the spine surgeon can minimizeby appropriate education and planning.

Results:

The advantages of the new system include increased clarity and more accurate definitions reflecting patient condition, information relevant to ambulatory and managed care encounters, expanded injury codes, laterality, specificity, precise data for safety and compliance reporting, data mining for research, and finally, enabling pay-for-performance programs. The disadvantages include the cost per physician, training administrative staff, revenue loss during the learning curve, confusion, the need to upgrade hardware along with software, and overall expense to the healthcare system.

Conclusions:

With the deadline rapidly approaching, gaps in implementation result in delayed billing, delayed or diminished reimbursements, and absence of quality and outcomes data. It is thereby essential for spine surgeons to understand their role in transitioning to this new environment. Part I of this article discusses the background, coding changes, and costs as well as reviews the salient features of ICD-10 in spine surgery

Implementation and impact of ICD-10 (Part II)

BACKGROUND

The transition from the International Classification of Disease-9(th) clinical modification to the new ICD-10 was all set to occur on 1 October 2015. The American Medical Association has previously been successful in delaying the transition by over 10 years and has been able to further postpone its introduction to 2015. The new system will overcome many of the limitations present in the older version, thus paving the way to more accurate capture of clinical information.

METHODS

The benefits of the new ICD-10 system include improved quality of care, potential cost savings, reduction of unpaid claims, and improved tracking of healthcare data. The areas where challenges will be evident include planning and implementation, the cost to transition, a shortage of qualified coders, training and education of the healthcare workforce, and a loss of productivity when this occurs. The impacts include substantial costs to the healthcare system, but the projected long-term savings and benefits will be significant. Improved fraud detection, accurate data entry, ability to analyze cost benefits with procedures, and enhanced quality outcome measures are the most significant beneficial factors with this change.

RESULTS

The present Current Procedural Terminology and Healthcare Common Procedure Coding System code sets will be used for reporting ambulatory procedures in the same manner as they have been. ICD-10-PCS will replace ICD-9 procedure codes for inpatient hospital services. The ICD-10-CM will replace the clinical code sets. Our article will focus on the challenges to execution of an ICD change and strategies to minimize risk while transitioning to the new system.

CONCLUSION

With the implementation deadline gradually approaching, spine surgery practices that include multidisciplinary health specialists have to anticipate and prepare for the ICD change in order to mitigate risk. Education and communication is the key to this process in spine practices.

A retrospective study of iliac crest bone grafting techniques with allograft reconstruction: do patients even know which iliac crest was harvested? Clinical article

OBJECT

Considerable biological research has been performed to aid bone healing in conjunction with lumbar fusion surgery. Iliac crest autograft is often considered the gold standard because it has the vital properties of being osteoconductive, osteoinductive, and osteogenic. However, graft site pain has been widely reported as the most common donor site morbidity. Autograft site pain has led many companies to develop an abundance of bone graft extenders, which have limited proof of efficacy. During the surgical consent process, many patients ask surgeons to avoid harvesting autograft because of the reported pain complications. The authors sought to study postoperative graft site pain by simply asking patients whether they knew which iliac crest was grafted when a single skin incision was made for the fusion operation.

METHODS

Twenty-five patients underwent iliac crest autografting with allograft reconstruction during instrumented lumbar fusion surgery. In all patients the autograft was harvested through the same skin incision but with a separate fascial incision. At various points postoperatively, the patients were asked if they could tell which iliac crest had been harvested, and if so, how much pain did it cause (10-point Numeric Rating Scale).

RESULTS

Most patients (64%) could not correctly determine which iliac crest had been harvested. Of the 9 patients who correctly identified the side of the autograft, 7 were only able to guess. The 2 patients who confidently identified the side of grafting had no pain at rest and mild pain with activity. One patient who incorrectly guessed the side of autografting did have significant sacroiliac joint degenerative pain bilaterally.

CONCLUSIONS

Results of this study indicate the inability of patients to clearly define their graft site after iliac crest autograft harvest with allograft reconstruction of the bony defect unless they have a separate skin incision. This simple, easily reproducible pilot study can be expanded into a larger, multiinstitutional investigation to provide more definitive answers regarding the ideal, safe, and cost-effective bone graft material to be used in spinal fusions.

Operating room radiation exposure in cone beam computed tomography-based, image-guided spinal surgery: clinical article

OBJECT

Surgeon and operating room (OR) staff radiation exposure during spinal surgery is a concern, especially with the increasing use of multiplanar fluoroscopy in minimally invasive spinal surgery procedures. Cone beam computed tomography (cbCT)-based, 3D image guidance does not involve the use of active fluoroscopy during instrumentation placement and therefore decreases radiation exposure for the surgeon and OR staff during spinal fusion procedures. However, the radiation scatter of a cbCT device can be similar to that of a standard 64-slice CT scanner and thus could expose the surgeon and OR staff to radiation during image acquisition. The purpose of the present study was to measure radiation exposure at several unshielded locations in the OR when using cbCT in conjunction with 3D image-guided spinal surgery in 25 spinal surgery cases.

METHODS

Five unshielded badge dosimeters were placed at set locations in the OR during 25 spinal surgery cases in which cbCT-based, 3D image guidance was used. The cbCT device (O-ARM) was used in conjunction with the Stealth S7 image-guided platform. The radiology department analyzed the badge dosimeters after completion of the last case.

RESULTS

Fifty high-definition O-ARM spins were performed in 25 patients for spinal registration and to check instrumentation placement. Image-guided placement of 124 screws from C-2 to the ileum was accomplished without complication. Badge dosimetry analysis revealed minimal radiation exposure for the badges 6 feet from the gantry in the area of the anesthesiology equipment, as well as for the badges located 10-13 feet from the gantry on each side of the room (mean 0.7-3.6 mrem/spin). The greatest radiation exposure occurred on the badge attached to the OR table within the gantry (mean 176.9 mrem/spin), as well as on the control panel adjacent to the gantry (mean 128.0 mrem/spin).

CONCLUSIONS

Radiation scatter from the O-ARM was minimal at various distances outside of and not adjacent to the gantry. Although the average radiation exposure at these locations was low, an earlier study, undertaken in a similar fashion, revealed no radiation exposure when the surgeon stood behind a lead shield. This simple precaution can eliminate the small amount of radiation exposure to OR staff in cases in which the O-ARM is used.

Placement of thoracic transvertebral pedicle screws using 3D image guidance

Object

Transvertebral pedicle screws have successfully been used in the treatment of high-grade L5–S1 spondylolisthesis. An advantage of transvertebral pedicle screws is the purchase of multiple cortical layers across 2 vertebrae, thereby increasing the stability of the construct. At the lumbosacral junction, transvertebral pedicle screws have been shown to be biomechanically superior to pedicle screws placed in the standard fashion. The use of transvertebral pedicle screws at spinal levels other than L5–S1 has not been reported in the literature. The authors describe their technique of transvertebral pedicle screw placement in the thoracic spine using 3D image guidance.

Methods

Twelve patients undergoing cervicothoracic or thoracolumbar fusion had 41 thoracic transvertebral pedicle screws placed across 26 spinal levels using this technique. Indications for placement of thoracic transvertebral pedicle screws in earlier cases included osteoporosis and pedicle screw salvage. However, in subsequent cases screws were placed in patients undergoing multilevel thoracolumbar fusion without osteoporosis, particularly near the top of the construct. Image guidance in this study was accomplished using the Medtronic StealthStation S7 image guidance system used in conjunction with the O-arm. All patients were slated to undergo postoperative CT scanning at approximately 4–6 months for fusion assessment, which also allowed for grading of the transvertebral pedicle screws.

Results

No thoracic transvertebral pedicle screw placed in this study had to be replaced or repositioned after intraoperative review of the cone beam CT scans. Review of the postoperative CT scans revealed all transvertebral screws to be across the superior disc space with the tips in the superior vertebral body. Six pedicle screws were placed using the in-out-in technique in patients with narrow pedicles, leaving 35 screws that underwent breach analysis. No pedicle breach was noted in 34 of 35 screws. A Grade 1 (< 2 mm) medial breach was noted in 1 screw without clinical consequence. Solid fusion was observed across 25 of 26 spinal levels that underwent transvertebral screw placement including 7 spinal levels located at the top of a multilevel construct.

Conclusions

This report describes the authors' initial in vivo experience with the 3D image-guided placement of 41 thoracic transvertebral pedicle screws. Advantages of thoracic transvertebral screws include the purchase of 2 vertebral segments across multiple cortical layers. A high fusion rate was observed across spinal levels in which transvertebral screws were placed. A formal biomechanical study is needed to assess the biomechanical advantages of this technique and is currently being planned.

Biomechanical analysis of a novel hook-screw technique for C1–2 stabilization

The Food and Drug Administration has not cleared the following medical devices for the use described in this study. The following medical devices are being discussed for an off-label use: cervical lateral mass screws.

Object

As an alternative for cases in which the anatomy and spatial relationship between C-2 and a vertebral artery precludes insertion of C-2 pedicle/pars or C1–2 transarticular screws, a technique that includes opposing laminar hooks (claw) at C-2 combined with C-1 lateral mass screws may be used. The biomechanical stability of this alternate technique was compared with that of a standard screw-rod technique in vitro.

Methods

Flexibility tests were performed in 7 specimens (occiput to C-3) in the following 6 different conditions: 1) intact; 2) after creating instability and attaching a posterior cable/graft at C1–2; 3) after removing the graft and attaching a construct comprising C-1 lateral mass screws and C-2 laminar claws; 4) after reattaching the posterior cable-graft at C1–2 (posterior hardware still in place); 5) after removing the posterior cable-graft and laminar hooks and placing C-2 pedicle screws interconnected to C-1 lateral mass screws via rod; and 6) after reattaching the posterior cable-graft at C1–2 (screw-rod construct still in place).

Results

All types of stabilization significantly reduced the range of motion, lax zone, and stiff zone compared with the intact condition. There was no significant biomechanical difference in terms of range of motion or lax zone between the screw-rod construct and the screw-claw-rod construct in any direction of loading.

Conclusions

The screw-claw-rod technique restricts motion much like the standard Harms technique, making it an acceptable alternative technique when aberrant arterial anatomy precludes the placement of C-2 pars/pedicle screws or C1–2 transarticular screws.

A review of image-guided spinal surgery

Image-guided spinal surgery has evolved rapidly in recent years. This review highlights the advances in image-guided spinal surgery during this evolution. The current literature regarding image-guided spinal surgery will be discussed. In addition, several aspects of image-guided spinal surgery will be focused on, including its learning curve and influence on operating room time, as well as its effect on surgeon radiation exposure. The accuracy of instrumentation placement with this technology and current applications will also be addressed.

Patients' perspective on full disclosure and informed consent regarding postoperative visual loss associated with spinal surgery in the prone position

OBJECTIVE

To determine patients' opinions regarding the person, method, and timing for disclosure of postoperative visual loss (POVL) associated with high-risk surgery.

PATIENTS AND METHODS

On the basis of findings of a pilot study involving 219 patients at Mayo Clinic in Florida, we hypothesized that at least 80% of patients would prefer disclosure of POVL by the surgeon, during a face-to-face discussion, before the day of scheduled surgery. To test the hypothesis, we sent a questionnaire to 437 patients who underwent prolonged prone spinal surgical procedures at Mayo Clinic in Rochester, MN, or Mayo Clinic in Arizona from December 1, 2008, to December 31, 2009.

RESULTS

Among the 184 respondents, 158 patients gave responses supporting the hypothesis vs 26 with at least 1 response not supporting it, for an observed incidence of 86%. The 2-sided 95% confidence interval is 80% to 91%.

CONCLUSION

At least 80% of patients prefer full disclosure of the risk of POVL, by the surgeon, during a face-to-face discussion before the day of scheduled surgery. This finding supports development of a national patient-driven guideline for disclosing the risk of POVL before prone spinal surgery.

Vertebral osteolysis originating from subchondral cyst end plate defects in transforaminal lumbar interbody fusion using rhBMP-2. Report of two cases

BACKGROUND CONTEXT

Vertebral osteolysis has been reported as a complication of off-label recombinant human bone morphogenetic protein-2 (rhBMP-2) use in transforaminal lumbar interbody fusion (TLIF). It has been postulated that end plate violation during disc space preparation, rhBMP-2 overdosing, or a combination thereof can contribute to the development of vertebral osteolysis when rhBMP-2 is used in the lumbar interspace.

PURPOSE

To present two cases of vertebral osteolysis that occurred after TLIF in which rhBMP-2 was used. In each case, the osteolysis originated from subchondral cysts that were present on preoperative computed tomographic (CT) scans.

STUDY DESIGN

Case report.

METHODS

Two patients underwent instrumented TLIF using INFUSE (Medtronic, Inc., Littleton, MA, USA) on an absorbable collagen sponge carrier. In each patient, approximately 4 mg of rhBMP-2 was placed anteriorly in the disc space with 0.1 mg of rhBMP-2 being placed inside a polyetheretherketone interbody cage. Morcellized allograft bone mixed with demineralized bone matrix was also placed in the disc space and cage. The remaining rhBMP-2 was placed posterolaterally on the contralateral side. Each patient presented with worsening back pain approximately 3 to 4 months postoperatively and CT scans revealed osteolysis affecting the L4 and L5 vertebral bodies. The osteolysis appeared to originate from preoperative vertebral defects caused by subchondral cysts.

RESULTS

One patient underwent removal of the interbody cage at the L4-L5 level and revision of the fusion with iliac crest autograft. At 15-month follow-up, he had no complaints of back pain, and CT scanning revealed solid fusion across the L4-L5 disc space. The other patient was offered revision of his fusion but declined any further surgery. At 2-year follow-up, that patient had persistent back pain but still declined any further surgery. A CT scan revealed unchanged osteolysis at the L4 and L5 levels.

CONCLUSIONS

It has been proposed that rhBMP-2-induced vertebral osteolysis occurring in TLIF procedures may be secondary to end plate violation during disc preparation or overdosing of rhBMP-2. Although overdosing may have also contributed to vertebral osteolysis in our two cases, the end plate violation from subchondral cyst formation that was present on preoperative CT scans seemed to be the origin of the osteolysis suggesting that the presence of preoperative subchondral cysts may be an additional risk factor for development of osteolysis in these patients.

Three-dimensional image-guided placement of S2 alar screws to adjunct or salvage lumbosacral fixation

BACKGROUND CONTEXT

Achieving fusion across the lumbosacral junction is challenging because of the unfavorable biomechanics associated with ending a fusion at this level. Bicortical placement of S1 pedicle screws can increase the construct stability at the lumbosacral junction; however, construct failure and pseudoarthrosis can still result. Iliac screws have been shown to increase the stiffness of lumbosacral constructs, but disadvantages include difficulty in connecting the iliac screw to adjacent sacral screws, painful screw loosening or prominence requiring removal, and the inability to place the screws in some patients with previous iliac crest autograft harvest.

PURPOSE

The purpose of the study is to describe a technique of S2 alar screw placement using three-dimensional image guidance.

STUDY DESIGN/SETTING

The study design is a retrospective analysis.

PATIENT SAMPLE

Twenty patients undergoing lumbosacral fusion had 32 screws placed using this technique.

OUTCOME MEASURES

An independent radiologist graded screw placement and lumbosacral fusion on thin-cut postoperative computed tomographic (CT) scans.

METHODS

Image guidance in this study was accomplished with the Medtronic Stealth Station Treon (Medtronic Inc., Littleton, MA, USA) used in conjunction with the O-ARM (Medtronic Inc.). Indications for placement of S2 alar screws included the following: to adjunct S1 pedicle screws in multilevel fusion cases; as an adjunct or alternative to S1 pedicle screws in pseudoarthrosis revision cases in which the S1 screws had loosened; as an alternative to S1 pedicle screws in cases where medial trajectory of an S1 pedicle screw was difficult to obtain because of a low-set lumbosacral junction; and a combination of the above. The entry point of the screw was typically chosen lateral and superior to the S2 dorsal foramen with the trajectory directed anterior, inferior, and lateral. Attempt was made to place the screw with the tip purchasing, but not penetrating through, the triangular area of cortical bone that can be found at the anterior, inferior, and lateral boundary of the sacral ala. An independent radiologist graded the placement of the screws on the intraoperative CT scan obtained with the O-ARM or on postoperative CT scans. Lumbosacral fusion was assessed on postoperative CT scans obtained at follow-up.

RESULTS

No complications occurred in this study as a result of S2 alar screw placement or image guidance. Five screws did penetrate the anterior cortex of the sacrum, with no clinical consequence. At the time of abstract submission, 16 patients were able to have follow-up CT scans, 15 of which were graded as solid fusion at the lumbosacral junction by the grading radiologist.

CONCLUSIONS

Three-dimensional image guidance allows for safe placement of large S2 sacral alar screws that can provide additional biomechanical stability to lumbosacral constructs or serve as an alternate point of sacral fixation when S1 pedicle screws cannot be salvaged or placed in a medial trajectory.

Image-guided placement of occipitocervical instrumentation using a reference arc attached to the headholder

OBJECTIVE

To develop a safe and accurate method of image-guided placement of instrumentation in the upper cervical spine and occiput in which the reference arc is fixed to the headholder.

METHODS

The authors describe a technique for placing screws at the occipital, C1, and C2 levels using 3-dimensional image guidance in which the reference arc is fixed to the headholder. Technical details are discussed as well as modifications to the technique to maximize navigation accuracy and decrease the need for re-registration. One of 2 paired systems, the BrainLAB Vector Vision system (BrainLAB Inc., Westchester, IL) used in conjunction with the Arcadis Orbic Isocentric C-arm (Siemens Medical Solutions, Erlangen, Germany) or the Stealth Treon system (Medtronic, Littleton, MA) paired with the O-arm (Medtronic), was used for image guidance in this study. A total of 18 patients had 82 screws placed at the occipital, C1, or C2 level using this technique. An independent radiologist interpreted postoperative computed tomographic scans of these patients and graded the screws for bony breach.

RESULTS

No complications resulted from the use of image guidance or from the placement of instrumentation. Postoperative computed tomography revealed 1 screw with a minimal breach of the outer lamina of C2. Another screw was replaced intraoperatively secondary to a minimal bony breach. No other bony breach occurred.

CONCLUSIONS

This technique allows safe and accurate placement of instrumentation in the posterior occipitocervical junction using 3-dimensional image guidance in which the reference arc is attached to the headholder.

Painful medial branch neuroma treated with minimally invasive medial branch neurectomy

STUDY DESIGN

Case report.

OBJECTIVE

To report an unusual complication following lumbar facet radiofrequency denervation and describe a successful, minimally invasive treatment of a presumed medial branch neuroma.

SUMMARY OF BACKGROUND DATA

Radiofrequency medial branch neurotomy is a common procedure for the treatment of mechanical back pain. Deafferentation injury and neuroma formation is well known and reported following chemical, surgical, and cryoablation neurolysis; however, it is thought to be rare with radiofrequency ablation. When this problem is encountered, treatment options appear to be limited. Further radiofrequency ablations may be ineffective and indeed may cause further injury.

METHODS

A 17-year-old male who sustained a traumatic fracture of the right L3-4 facet joint presented with increasing back pain after multiple radiofrequency ablations of the medial branches of the L2 and L3 dorsal rami. The description of the back pain, initially nociceptive in nature, had become progressively neuropathic with clear focal areas of allodynia and hyperesthesia. Further medial branch radiofrequency denervation was found to be ineffective.

RESULTS

Diagnostic block of the right medial branch of the L2 dorsal ramus provided the patient with total relief of pain. This was followed by a minimally invasive open surgical ablation of the L2 medial branch neuroma using three-dimensional, fluoroscopy-based image guidance. At 7 months of follow-up, the patient reported complete resolution of pain, discontinuation of all pain medications, and return to all previous physical activities.

CONCLUSION

Deafferentation injury is a rare but recognized complication of chemical, surgical, and thermal neuroablation. This case report presents a rare instance of presumed neuroma formation following multiple radiofrequency ablations for the treatment of facet-generated mechanical back pain. Open and minimally invasive medial branch neurectomy resulted in complete resolution of pain and return to baseline function.

Rheumatoid Arthritis of the Craniovertebral Junction

BACKGROUND

Rheumatoid arthritis (RA) is the most common inflammatory disease involving the spine. It has a predilection for involving the craniocervical spine. Despite widespread involvement of the cervical spine with RA, few patients need surgery. The 3 major spinal manifestations of RA in the cervical spine are basilar invagination, atlantoaxial instability, and subaxial subluxations. Surgical management of RA involving the craniovertebral junction remains a challenge despite a decline in severe cases and an improvement in surgical techniques.

METHODS

We conducted an exhaustive review of English-language publications discussing RA involving the craniovertebral junction. We paid special attention to publications detailing modern surgical management of these conditions. In addition, we outline our own surgical experience with such patients.

RESULTS

We discuss alternative surgical methods for treating basilar invagination, atlantoaxial instability, and concurrent subaxial subluxations. We detail our surgical technique for transoral odontoidectomy, occipital cervical fusion, and atlantoaxial fusion. We detail the use of spinal surgical navigation in both of these procedures.

CONCLUSION

Surgical management of RA remains a challenging field. There clearly has been a decrease in cases of mutilating RA involving the craniovertebral junction. Surgical techniques for managing these conditions have steadily improved.

Iatrogenic intradural spinal arachnoid cyst as a complication of lumbar spine surgery

Iatrogenic spinal arachnoid cysts are rare, but have been described as a complication of spinal injection and lumbar puncture procedures. The authors describe 2 cases of iatrogenic spinal arachnoid cyst formation that occurred after incidental durotomy during lumbar spine surgery. In both cases, postoperative MR imaging revealed compression of the cauda equina by an intradural arachnoid cyst. Intradural exploration and fenestration of the arachnoid cyst was accomplished in each case. This entity should be considered in the differential diagnosis of a patient experiencing symptoms of neurological compression after a lumbar surgery complicated by incidental durotomy.

Placement of thoracolumbar pedicle screws using three-dimensional image guidance: experience in a large patient cohort

OBJECT

The goal of this study was to analyze the placement accuracy and complications of thoracolumbar pedicle screws (PSs) inserted using 3D image guidance in a large patient cohort.

METHODS

The authors reviewed the charts of 220 consecutive patients undergoing posterior spinal fusion using 3D image guidance for instrumentation placement. A total of 1084 thoracolumbar PSs were placed using either the BrainLAB Vector Vision (BrainLAB, Inc.) or Medtronic StealthStation Treon (Medtronic, Inc.) image guidance systems. Postoperative CT scanning was performed in 184 patients, allowing for 951 screws to be graded by an independent radiologist for bone breach. All complications resulting from instrumentation placement were noted. Using the intraoperative planning function of the image-guided system, the largest diameter screw possible in each particular case was placed. The screw diameter of instrumentation placed into the L3-S1 levels was noted.

RESULTS

No vascular or visceral complications occurred as a result of screw placement. Two nerve root injuries occurred in 1084 screws placed, resulting in a 0.2% per screw incidence and a 0.9% patient incidence of nerve root injury. Neither nerve root injury was associated with a motor deficit. The breach rate was 7.5%. Grade 1 and minor anterolateral "tip out" breaches accounted for 90% of the total breaches. Patients undergoing revision surgery accounted for 46% of the patients in this study. Accordingly, 154 screws placed through previous fusion mass could be evaluated using postoperative CT scanning. The breach rate in this specific cohort was 7.8%. A total of 765 PSs were placed into the L3-S1 levels in this study; 546 (71%) of these screws were > or = 7.5 mm in diameter. No statistical difference in breach rate was noted in PSs placed through revision spinal levels versus nonrevision spinal levels (p = 0.499). Additionally, no increase in breach rate was noted with placement of 7.5-mm-diameter screws.

CONCLUSIONS

Three-dimensional image guidance is a useful adjunct to placement of spinal instrumentation. The complication rate in this study was low, and accurate placement of instrumentation was achieved despite the high percentage of revision surgery cases in our patient population. Additionally, because active fluoroscopy was not used for instrumentation placement, there was minimal to no radiation exposure to the surgeon or operating room staff.

Stabilization of the atlantoaxial complex via C-1 lateral mass and C-2 pedicle screw fixation in a multicenter clinical experience in 102 patients: modification of the Harms and Goel techniques

Object

Stabilization of the atlantoaxial complex has proven to be very challenging. Because of the high mobility of the C1–2 motion segment, fusion rates at this level have been substantially lower than those at the subaxial spine. The set of potential surgical interventions is limited by the anatomy of this region. In 2001 Jürgen Harms described a novel technique for individual fixation of the C-1 lateral mass and the C-2 pedicle by using polyaxial screws and rods. This method has been shown to confer excellent stability in biomechanical studies. Cadaveric and radiographic analyses have indicated that it is safe with respect to osseous and vascular anatomy. Clinical outcome studies and fusion rates have been limited to small case series thus far. The authors reviewed the multicenter experience with 102 patients undergoing C1–2 fusion via the polyaxial screw/rod technique. They also describe a modification to the Harms technique.

Methods

One hundred two patients (60 female and 42 male) with an average age of 62 years were included in this analysis. The average follow-up was 16.4 months. Indications for surgery were instability at the C1–2 level, and a chronic Type II odontoid fracture was the most frequent underlying cause. All patients had evidence of instability on flexion and extension studies. All underwent posterior C-1 lateral mass to C-2 pedicle or pars screw fixation, according to the method of Harms. Thirty-nine patients also underwent distraction and placement of an allograft spacer into the C1–2 joint, the authors' modification of the Harms technique. None of the patients had supplemental sublaminar wiring.

Results

All but 2 patients with at least a 12-month follow-up had radiographic evidence of fusion or lack of motion on flexion and extension films. All patients with an allograft spacer demonstrated bridging bone across the joint space on plain x-ray films and computed tomography. The C-2 root was sacrificed bilaterally in all patients. A postoperative wound infection developed in 4 patients and was treated conservatively with antibiotics and local wound care. One patient required surgical debridement of the wound. No patient suffered a neurological injury. Unfavorable anatomy precluded the use of C-2 pedicle screws in 23 patients, and thus, they underwent placement of pars screws instead.

Conclusions

Fusion of C1–2 according to the Harms technique is a safe and effective treatment modality. It is suitable for a wide variety of fracture patterns, congenital abnormalities, or other causes of atlantoaxial instability. Modification of the Harms technique with distraction and placement of an allograft spacer in the joint space may restore C1–2 height and enhance radiographic detection of fusion by demonstrating a graft–bone interface on plain x-ray films, which is easier to visualize than the C1–2 joint.

Placement of C2 laminar screws using three-dimensional fluoroscopy-based image guidance

The use of C2 laminar screws in posterior cervical fusion is a relatively new technique that provides rigid fixation of the axis with minimal risk to the vertebral artery. The techniques of C2 laminar screw placement described in the literature rely solely on anatomical landmarks to guide screw insertion. The authors report on their experience with placement of C2 laminar screws using three-dimensional (3D) fluoroscopy-based image-guidance in eight patients undergoing posterior cervical fusion. Overall, fifteen C2 laminar screws were placed. There were no complications in any of the patients. Average follow-up was 10 months (range 3-14 months). Postoperative computed tomographic (CT) scanning was available for seven patients allowing evaluation of placement of thirteen C2 laminar screws, all of which were in good position with no spinal canal violation. The intraoperative planning function of the image-guided system allowed for 4-mm diameter screws to be placed in all cases. Using modified Odom's criteria, excellent or good relief of preoperative symptoms was noted in all patients at final follow-up.

Timing of Paired Points and Surface Matching Registration in Three-Dimensional (3D) Image-guided Spinal Surgery

Image-guidance can increase the safety and accuracy of spinal instrumentation placement. However, many spine surgeons are reluctant to incorporate spinal image-guidance into their surgical practice due to the perception that it is time-consuming and tedious, especially the task of vertebral registration. The authors evaluated the time required for paired points and surface matching registration when using the BrainLAB (BrainLAB, Westchester, IL) image-guided spine application for spinal surgery cases. The time required to register vertebral segments using paired points and surface matching techniques was assessed in 13 consecutive patients undergoing spinal fusions by the senior author. Overall, 23 vertebral segments were registered spanning from T1 to S1. Note was made of the vertebral segments that required reregistration due to poor accuracy. The average time required to register a single vertebral segment using the paired points and surface matching technique was 117 seconds (1 min 57 s). Average accuracy obtained was 0.9 mm. Inaccurate registration occurred in 3/23 (13%) of the segments requiring a second attempt at registration. In 3/23 (13%) of segments, adequate navigation accuracy was maintained on an adjacent vertebral segment thereby allowing for instrumentation to be placed in that adjacent segment without having to register that segment. Though associated with a learning curve, image-guidance can be used effectively and efficiently in spinal surgery. Average time required for registration of a vertebral segment using the BrainLAB spine application in this study was less than 2 minutes. The average accuracy obtained was 0.9 mm.

Early complications of posterior rod-screw fixation of the cervical and upper thoracic spine

OBJECTIVE

The technique of rod-screw fixation of the cervical spine is well described. However, there is very little data on the complications incurred by the application of these devices. The purpose of this study was to quantify the risks associated with rod fixation of the cervical spine.

METHODS

A prospective study was performed on 100 consecutive patients treated with this technique. Clinical and radiographic assessment was performed immediately after surgery 3, 6, and 12 months postoperatively, and annually thereafter. The mean follow-up interval was 16.7 months.

RESULTS

A total of 888 screws were implanted in 100 patients. Perioperative complications included radiculopathy (n = 4, 0.45% per screw placed), infection and other wound-healing problems (n = 4), screw malposition (n = 2), loss of alignment (n = 1), and cerebrospinal fluid leak (n = 1). There were no examples of spinal cord or vertebral artery injury. Early complications (within 6 mo of surgery) included pseudarthrosis (n = 2) and screw breakage (n = 2, 0.22% per screw placed). There were no late complications. Reoperation was required in eight cases, all within 6 months of the index procedure. Indications for reoperation included wound-healing problems (n = 4), malpositioned screw (n = 2), and pseudarthrosis (n = 2). No patient required another operation for any indication beyond the 6-month postoperative interval.

CONCLUSION

Rod-screw fixation was an effective method of posterior cervical stabilization that could be safely applied in a wide range of spinal disorders. In a complex group of patients, the complication rates were modest, and compared favorably with other methods of fixation.

Biomechanical analysis of rigid stabilization techniques for three-column injury in the lower cervical spine

STUDY DESIGN

Comparison of nondestructive multidirectional flexibility in groups of specimens receiving two different posterior instrumentation constructs with or without anterior plating.

OBJECTIVE

To compare stability after a three-column injury stabilized posteriorly by lateral mass screws-rods at C5-C6 and pedicle screws-rods at C7 ("LLP") or by pedicle screws-rods at C5-C6-C7 ("PPP"), and to compare posterior, anterior, and combined anterior-posterior fixation.

SUMMARY OF BACKGROUND DATA

Pedicle screws resist pullout better than lateral mass screws, but little research has compared the stability of pedicle screws to that of lateral mass screws used within constructs.

METHODS

Fourteen human cadaveric C4-T1 specimens were tested intact, posteriorly instrumented (7 LLP and 7 PPP), anteriorly instrumented, or with combined (anterior-posterior) instrumentation. Nonconstraining, nondestructive torques induced flexion, extension, lateral bending, and axial rotation while angular motion was recorded optically.

RESULTS

Posterior, anterior, and combined instrumentation each significantly improved stability (P < 0.05). Combined fixation provided significantly better stability than either anterior or posterior instrumentation alone. In no loading mode and in no testing condition was any parameter significantly different between LLP and PPP. Posterior instrumentation provided significantly better stability than anterior instrumentation.

CONCLUSIONS

Anterior plate and posterior screw-rod fixation alone improve stability in a two-level, three-column cervical injury model. Combined fixation further improves stability. There is little discernible difference in immediate postoperative stability between posterior rod constructs combining lateral mass and pedicle screws and those using only pedicle screws.

Balloon kyphoplasty for treatment of sacral insufficiency fractures. Report of three cases

Sacral insufficiency fracture is a painful injury, for which no effective treatment currently exists. The objective of this study was to report on the clinical outcomes and technical aspects of balloon kyphoplasty, which was used in three patients with this injury. Three elderly women with intractable pain from sacral insufficiency fractures were treated with polymethyl methacrylate (PMMA) injections into the sacrum by using a modified balloon kyphoplasty procedure. The visual analog scale pain score improved by four points in each case. Functional status was improved and analgesic medication requirements were decreased in all three patients. There were no complications associated with the procedure. Because of the unique anatomy of the sacrum, it was difficult to monitor instrument placement and PMMA injection by using conventional fluoroscopy. BrainLAB image guidance was used in one case, and was helpful in guiding instrument placement and assuring accurate PMMA deposition at the fracture site. Balloon kyphoplasty may be a treatment alternative in selected patients with sacral insufficiency fractures. BrainLAB image guidance may offer some advantages over conventional fluoroscopy with regard to the monitoring of instrument placement and PMMA injection.

Balloon kyphoplasty for treatment of sacral insufficiency fractures

Sacral insufficiency fracture is a painful injury, for which no effective treatment currently exists. The objective of this study was to report on the clinical outcomes and technical aspects of balloon kyphoplasty, which was used in three patients with this injury.

Three elderly women with intractable pain from sacral insufficiency fractures were treated with polymethyl methacrylate (PMMA) injections into the sacrum by using a modified balloon kyphoplasty procedure. The visual analog scale pain score improved by four points in each case. Functional status was improved and analgesic medication requirements were decreased in all three patients. There were no complications associated with the procedure.

Because of the unique anatomy of the sacrum, it was difficult to monitor instrument placement and PMMA injection by using conventional fluoroscopy. BrainLAB image guidance was used in one case, and was helpful in guiding instrument placement and assuring accurate PMMA deposition at the fracture site.

Balloon kyphoplasty may be a treatment alternative in selected patients with sacral insufficiency fractures. BrainLAB image guidance may offer some advantages over conventional fluoroscopy with regard to the monitoring of instrument placement and PMMA injection.

Delayed onset of generalized tonic-clonic seizures as a complication of halo orthosis. Case report

The authors report on the case of a 29-year-old man who presented with new-onset, generalized tonic-clonic seizures 11 years after being treated with a halo orthosis for a neurologically intact C-7 fracture. Neuroimaging and surgical findings indicated that the epileptic focus was scar tissue, which developed secondary to halo pin penetration of the skull. This complication of halo orthosis has not yet been reported in the literature.