Paraplegia resulting from vessel ligation

Safety and efficacy of posterior vertebral column resection in complex pediatric deformities

Background

Vertebral column resection (VCR) is a well-known technique used for correction of complex spinal deformities. VCR could be done through a posterior only approach (Pvcr), or a combined anteroposterior approach, with almost comparable results. Early studies of Pvcr have reported high rates of complications, while subsequent studies have reported a reasonable complication rate. In this study, the authors represent and evaluate the initial results of using the Pvcr technique to correct complex pediatric deformities.

Objective

To evaluate the safety and efficacy of performing Pvcr to correct complex pediatric deformities.

Methods

Retrospective cohort study of data was collected from the database of pediatric deformity patients who were operated for correction of their deformities using posterior instrumentation and Pvcr at a single institution from 2015 to 2019.

Results

Twenty-one pediatric patients with a mean age 15.2 ± 3.5 years were enrolled in this study. The mean follow-up period was 26.3 ± 3.1 months. The mean Cobb angle has been decreased significantly from 82.9 ± 23.9 degrees to 28.8 ± 14.2 immediately after correction (correction rate 66.9 ± 10.8%, p < 0.001) with slight increase to 30.2 ± 14.9 after 24 months of follow-up (correction loss 4.3 ± 3.1%). The mean kyphotic angle has decreased significantly from 74.1 ± 15.9 to 25.4 ± 4.5 immediately after correction (correction rate 65.4 ± 2.9%, p < 0.001) with slight increase to 26.7 ± 5.2 after 24 months of follow-up (correction loss 4.8 ± 3.5%). The mean estimated blood loss was 2816.7 ± 1441.5 ml. The mean operative time was 339 ± 84.3 min. Self-image domain (part of SRS-22 questionnaire) has significantly improved from a mean preoperative of 2.3 ± 0.5 to a mean postoperative of 3.9 ± 0.4 after 24 months of correction (p < 0.001). As regards complications, chest tubes were inserted in 17 cases (81%), one case (4.8%) had suffered from deep wound infection and temporary respiratory failure, while 3 cases (14.3%) had neurological deficits.

Conclusion

Posterior vertebral column resection is considered a highly effective release procedure that aids in the correction of almost any type of complex pediatric deformities with a correction rate reaching 66.9 ± 10.8%. However, Pvcr is a challenging procedure with high estimated blood loss and risk of neurological deficits, so it must be done only by experienced spine surgeons in the presence of good anesthesia and neuromonitoring teams.

Anterior Spinal Artery Syndrome Occurring after One Level Segmental Artery Ligation during Spinal Surgery

In treating the ventral pathology of spine, ligating the segmental vessels is sometimes necessary. This may cause spinal cord ischemia, and concerns of neurologic injury have been presented. However, spinal cord ischemic injury after sacrificing segmental vessels during spine surgery is very rare. Reports of this have been scarce in the literature and most of these complications occur after multi-level segmental vessel ligation. Here we report a case of a patient with postoperative anterior spinal artery syndrome, which occurred after ligating one level segmental vessels during spinal surgery for a T8 vertebral pathologic fracture. Despite its rarity, the risk of spinal cord ischemic injury after segmental vessel ligation is certainly present. Surgeons must keep in mind such risk, and surgery should be planned under a careful risk-benefit consideration.

Complications of thoracic spine surgery - Their avoidance and management

As the surgical techniques have been significantly developed, thoracic spine surgery is currently increasingly indicated for a variety of pathologies such as degenerative spondylosis, ligament ossification, spinal deformity, infectious diseases, trauma and tumors. Thoracic spine has the distinctive anatomy with the rib attachment and the proximity to great vessels and lungs, and spinal cord has particular vulnerability due to its unique circulation system. Thus, both anterior and posterior approach surgeries have their own risks unique to this spinal segment. To be capable of challenging the spinal disorders in thoracic spine, surgeons must be aware of possible complications and their avoidance methods as well as management strategy. In the present narrative review paper, the complications in thoracic spine surgery are categorized into approach-related complications, neurological complications, wound-related complications, mechanical and instrument-related complications, as well as medical complications along with pre-, intra- and post-operative considerations. Their pathologies, possible sequelae, incidence, risk factors, prevention and management are discussed. As for some of the complications that are also commonly seen in cervical or lumbar spine, focus is placed on their importance in thoracic spine surgery. To prevent these adverse events associated with thoracic spine surgery, surgeons should be familiar with detailed knowledge of thoracic anatomy related to its approach as well as physiological characteristics.

Spinal neurovascular complications with anterior thoracolumbar spine surgery: a systematic review and review of thoracolumbar vascular anatomy

OBJECTIVE

Spinal cord infarction due to interruption of the spinal vascular supply during anterior thoracolumbar surgery is a rare but devastating complication. Here, the authors sought to summarize the data on this complication in terms of its incidence, risk factors, and operative considerations. They also sought to summarize the relevant spinal vascular anatomy.

METHODS

They performed a systematic literature review of the PubMed, Scopus, and Embase databases to identify reports of spinal cord vascular injury related to anterior thoracolumbar spine procedures as well as operative adjuncts and considerations related to management of the segmental artery ligation during such anterior procedures. Titles and abstracts were screened, and studies meeting inclusion criteria were reviewed in full.

RESULTS

Of 1200 articles identified on the initial screening, 16 met the inclusion criteria and consisted of 2 prospective cohort studies, 10 retrospective cohort studies, and 4 case reports. Four studies reported on the incidence of spinal cord ischemia with anterior thoracolumbar surgery, which ranged from 0% to 0.75%. Eight studies presented patient-level data for 13 cases of spinal cord ischemia after anterior thoracolumbar spine surgery. Proposed risk factors for vasculogenic spinal injury with anterior thoracolumbar surgery included hyperkyphosis, prior spinal deformity surgery, combined anterior-posterior procedures, left-sided approaches, operating on the concavity side of a scoliotic curve, and intra- or postoperative hypotension. In addition, eight studies analyzed operative considerations to reduce spinal cord ischemic complications in anterior thoracolumbar surgery, including intraoperative neuromonitoring and preoperative spinal angiography.

CONCLUSIONS

While spinal cord infarction related to anterior thoracolumbar surgery is rare, it warrants proper consideration in the pre-, intra-, and postoperative periods. The spine surgeon must be aware of the relevant risk factors as well as the pre- and intraoperative adjuncts that can minimize these risks. Most importantly, an understanding of the relevant spinal vascular anatomy is critical to minimizing the risks associated with anterior thoracolumbar spine surgery.

Complications of Thoracolumbar Adult Spinal Deformity Surgery

Adult spinal deformity (ASD) is a challenging problem for spine surgeons given the high risk of complications, both medical and surgical. Surgeons should have a high index of suspicion for medical complications, including cardiac, pulmonary, thromboembolic, genitourinary and gastrointestinal, renal, cognitive and psychiatric, and skin conditions, in the perioperative period and have a low threshold for involving specialists. Surgical complications, including neurologic injuries, vascular injuries, proximal junctional kyphosis, durotomy, and pseudarthrosis and rod fracture, can be devastating for the patient and costly to the health-care system. Mortality rates have been reported to be between 1.0% and 3.5% following ASD surgery. With the increasing rate of ASD surgery, surgeons should properly counsel patients about these risks and have a high index of suspicion for complications in the perioperative period.

Preoperative CT Angiography Informs Instrumentation in Anterior Spine Surgery for Idiopathic Scoliosis

The objective of this study is to evaluate whether the artery of Adamkiewicz localization with preoperative CT angiography influences anterior spinal instrumentation.

Methods

Children with idiopathic scoliosis who underwent anterior instrumentation and with a preoperative CT angiography were evaluated retrospectively. Data included curve type, artery of Adamkiewicz level/laterality, surgical approach laterality, number of instrumented levels and segmental vessels ligated, intraoperative neuromonitoring changes, and postoperative neural complications.

Results

Thirty-nine girls and eight boys (mean age 12 years [6.7 to 16.8 years]) were analyzed. Instrumented curves indicate 28 thoracic, 14 thoracolumbar, and seven double major. The artery of Adamkiewicz: T6 (left-1), T8 (left-1), T9 (left-4/right-2), T10 (left-11/right-4), T11 (left-4/right-4), T12 (left-1/right-2), L1 (left-2/right-1), and L2 (left-3/right-2). Four had bilateral dominant segmentals, whereas in nine patients, none was identified. T10 (32%) and left side (57%) were most frequent. On average, 7.1 (4 to 11) segmentals were ligated per case (total 355). Dominant vessels were ipsilateral to/within instrumentation levels in 30%.

Discussion

In children with idiopathic scoliosis who underwent anterior instrumentation, the artery of Adamkiewicz was identified on the left in >50% and at T10 in 32%. In one-third of the patients, the artery was within intended surgical levels and resulted in instrumentation modification.

Retroperitoneal Extrapleural Approach for Corpectomy of the First Lumbar Vertebra : Technique and Outcome

Objective

Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy.

Methods

Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months.

Results

The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected.

Conclusion

The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior load-bearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

[Modern Aspects of Lung Cancer Surgery]

Modern Aspects of Lung Cancer Surgery Abstract. Surgery is still an inherent part of the treatment of non-small cell lung cancer. This article summarizes various aspects of the surgical treatment of early and locally advanced stages of lung cancer. Minimally invasive techniques for lung cancer resection - video- or robotic-assisted - are today standard for early stages. Perioperative mortality is below 1 % and the oncological outcome is equal to open surgery. The learning curve is at 50 VATS lobectomies in a program with a minimum of 25 VATS lobectomies/year to obtain satisfying results. In specialized centers, Locally advanced tumors can be resected technically and oncologically safe, with acceptable morbidity and mortality rates. With careful patient selection and planning, 5-year survival rates can be as high as 48 %.

Intraoperative monitoring for spinal radiculomedullary artery aneurysm occlusion treatment: What, when, and how long?

BACKGROUND

Spinal radiculomedullary artery aneurysms are extremely rare. Treatment should be tailored to clinical presentation, distal aneurysm flow, and lesion anatomical features. When a surgical occlusion is planned, it is necessary to evaluate whether intraoperative monitoring (IOM) should be considered as an indispensable tool to prevent potential spinal cord ischemia.

METHODS

We present a patient with symptoms and signs of spinal subarachnoid hemorrhage resulting from the rupture of a T4 anterior radiculomedullary aneurysm who underwent open surgical treatment under motor evoked potential (MEP) monitoring.

RESULTS

Due to the aneurysmal fusiform shape and preserved distal flow, the afferent left anterior radiculomedullary artery was temporarily clipped; 2 minutes after the clamping, the threshold stimulation level rose higher than 100 V, and at minute 3, MEPs amplitude became attenuated over 50%. This was considered as a warning criteria to leave the vessel occlusion. The radiculomedullary aneurysm walls were reinforced and wrapped with muscle and fibrin glue to prevent re-bleeding. The patient awoke from general anesthesia without focal neurologic deficit and made an uneventful recovery with complete resolution of her symptoms and signs.

CONCLUSION

This paper attempts to build awareness of the possibility to cause or worsen a neurological deficit if a radiculomedullary aneurysm with preserved distal flow is clipped or embolized without an optimal IOM control. We report in detail MEP monitoring during the occlusion of a unilateral T4 segmental artery that supplies an anterior radiculomedullary artery aneurysm.

The effect from different numbers of segmental arteries ligation to the spinal cord in the clinical practice of posterior vertebral column resection correction

PURPOSE

In using posterior vertebral column resection (PVCR) to treat severe kyphoscoliosis, it is unavoidable to ligate and cut off several segmental arteries (SAs) of the spinal cord for exposure and hemostasis, but which would raise the neurological risks. The aim of this study is to explore the changes of intraoperative spinal cord monitoring (IOM) following ligating different numbers of SAs in PVCR.

METHODS

Twenty-one consecutive patients with severe kyphoscoliosis were included and treated by PVCR correction. In operation, according to ligate different numbers of SAs, the IOM changes were recorded, respectively. Examinations of the covariance between different numbers of SAs ligations and IOM changes were performed to reveal the effect to the spinal cord by SAs ligations.

RESULTS

In all the 21 cases, averaging 1.9 pairs of SAs were ligated. With the increased numbers of ligations, SSEP amplitudes and latencies were changed more obviously: from 1 to 3 pairs ligations, the mean decreased percentages of amplitudes were from 53.20 to 78.15%, the mean increased percentages of latency were from 1.23 to 1.40%, and the mean durations of decreased SSEP amplitudes were from 3.23 to 5.2 min; but without abnormal MEP changes. None occurred postoperative or delayed neurological deficit. Correlation analysis identified significant correlations between the number of SAs ligation and decreased percentage of SSEP amplitude (r = 0.945, P < 0.0001), and between the number of SAs being ligated and the duration of SSEP change (r = 0.945, P = 0.0002).

CONCLUSIONS

Following the increased number of SAs ligation, the amplitude of SSEP is decreased more obviously with a much longer duration of recovery and the risk to spinal cord will be increased greatly. In the PVCR correction on the basis of spinal shortening, the numbers of SAs ligations should be as less as possible for neurological safety.

Spinal Cord Blood Supply and Its Surgical Implications

The blood supply to the spine is based on a predictable segmental vascular structure at each spinal level, but true radiculomedullary arteries, which feed the dominant cord supply vessel, the anterior spinal artery, are relatively few and their locations variable. Under pathologic conditions, such as aortic stent grafting, spinal deformity surgery, or spinal tumor resection, sacrifice of a dominant radiculomedullary vessel may or may not lead to spinal cord ischemia, depending on dynamic autoregulatory or collateral mechanisms to compensate for its loss. Elucidation of the exact mechanisms for this compensation requires further study but will be aided by preoperative, intraoperative, and postoperative comparative angiography. Protocols in place at our center and others minimize the risk of spinal cord ischemia during planned radiculomedullary vessel sacrifice.

Early outcomes and complications of posterior vertebral column resection

BACKGROUND CONTEXT

Hyperkyphosis confers a significant risk for neurologic deterioration as well as compromised cardiopulmonary function. Posterior vertebral column resection (PVCR) is a challenging but effective technique for spinal cord decompression and deformity correction that even under the setting of limited resources can be performed to reduce the technical difficulties, the operating time, and possibly the complications of the traditional two-staged vertebral column resection (VCR).

PURPOSE

To report on the results of VCR performed through a single posterior approach (PVCR) in the treatment of severe rigid kyphosis in a series of patients treated and followed at a Scoliosis Research Society Global Outreach Program site in West Africa.

STUDY DESIGN

Retrospective case series.

PATIENT SAMPLE

Forty-five consecutive patients treated with PVCR for correction of severe rigid kyphosis.

OUTCOME MEASURES

Clinical and radiographic outcomes and complications; Scoliosis Research Society outcome instrument (SRS-22).

METHODS

From 2002 to 2009, 45 patients (20 male and 25 female) underwent PVCR for kyphosis from congenital deformity (nine) or secondary to tuberculosis of the spine (36). Preoperative demographics, preop and postop neurologic status, SRS-22 scores and complications were recorded; upright full spine X-rays were available in all patients. Mean age was 14 years (6-47 years); mean follow-up 27 months (2-79 months). Mean preoperative kyphosis measured 108°. The deformity apex was resected via a costotransverse (thoracic) or posterolateral (lumbar) approach; neurosurveillance with sensory (somatosensory-evoked potentials) and motor (motor-evoked potentials) potential was used in all cases. Posterior instrumentation was used in all patients, and anterior structural cage was used in 32 patients.

RESULTS

Intraoperative monitoring changes occurred in 10 patients (22%), and one patient progressed to complete spinal cord injury. Average preoperative local kyphosis was 108° and corrected to 600 postoperatively. Postoperatively, no additional patient showed neurologic deterioration; of the 11 patients with preoperative gait disturbances, 4 improved to normal gait, 5 remained the same, and 2 showed deterioration of their walking ability to nonambulating level. Total SRS-22 scores improved from 3.18 to 3.54 (p=.01), primarily self-image domain.

CONCLUSIONS

Posterior vertebral column resection was successfully undertaken for the management of thoracic and thoracolumbar hyperkyphosis, demonstrating improvements in overall kyphosis and clinical outcome. Neuromonitoring provided the required safety to perform these challenging complex spine deformity procedures.

Complications during anterior surgery of the lumbar spine: an anatomically based study and review

Procedures involving anterior surgical decompression and fusion are being performed with increasing frequency for the treatment of a variety of pathological processes of the spine including trauma, deformity, infection, degenerative disease, failed-back syndrome, discogenic pain, metastases, and primary spinal neoplasms. Because these operations involve anatomy that is often unfamiliar to many neurological and orthopedic surgeons, a significant proportion of the associated complications are not related to the actual decompressive or fusion procedure but instead to the actual exposure itself. To understand the nature of these injuries, a detailed anatomical study and dissection was undertaken in six cadaveric specimens. Critical structures at risk in the abdomen and retroperitoneum were identified, and their anatomical relationships were categorized and photographed. These structures included the psoas muscle, kidneys, ureters, diaphragm and crura, esophageal hiatus, thoracic duct, greater splanchnic nerves, phrenic nerves, sympathetic chains, medial arcuate ligament, superior and inferior hypogastric plexus, segmental and radicular vertebral vessels, aorta, vena cava, median sacral artery, common iliac vessels, iliolumbar veins, lumbosacral plexus, and presacral hypogastric plexus. Based on these dissections and an extensive review of the literature, the authors provide a detailed anatomically based discussion of the complications associated with anterior lumbar surgery.

Surgical view of the lumbar arteries and their branches: an anatomical study

BACKGROUND

Although injury to the lumbar arteries during anterior spinal approaches is often encountered, there are few published articles regarding the relationship between the lumbar arteries and spinal cord ischemia.

OBJECTIVE

To examine the morphology of the lumbar arteries and to emphasize their clinical importance.

METHODS

With the aid of a surgical microscope, 80 lumbar arteries in 10 formalin-fixed male cadavers were studied. Measurements of these structures were made and relationships observed.

RESULTS

The spinal artery was usually the first branch of the lumbar artery. The greatest lumbar artery diameter was at L4 and had a mean diameter of 3.25 mm; the smallest diameter was identified at L2 and had a mean diameter of 2.05 mm. The largest spinal artery diameter was at L3 (mean, 0.56 mm) and the smallest at L1 (mean, 0.42 mm). The largest anastomotic artery diameter was at L4 (mean, 0.42 mm) and the smallest at L1 (mean, 0.32 mm). For the right and left sides, the mean greatest distance between the origin of the lumbar artery and the tendinous arch was at L4 (mean, 40.9 and 31.8 mm, respectively) and the least at L1 (mean, 31.8 and 22.5 mm, respectively). The mean of the greatest distance between the anastomotic branch and the base of the transverse process of the lumbar vertebrae was at L4 (mean, 4.41 and 4.35 mm, respectively) and the smallest at L1 (mean, 4.04 and 4.08 mm, respectively).

CONCLUSION

These anatomic findings of the lumbar segmental arteries would be useful for emphasizing their surgical importance.

Neurologic injury in the surgical treatment of idiopathic scoliosis: guidelines for assessment and management

Iatrogenic spinal cord injury resulting from surgical treatment of spinal deformity is a relatively uncommon but devastating complication. Publications on the prevalence of spinal cord injury following surgery are numerous, but no definitive review with clinically pertinent treatment guidelines exists. Methods to reduce the risk of neurologic complications with scoliosis surgery include adequate patient evaluation and preoperative planning, intraoperative preparation, intraoperative neuromonitoring, and postoperative management. Treatment algorithms may be useful in the clinical setting to manage intraoperative or postoperative neurologic injury.

Segmental vessel ligation in patients undergoing surgery for anterior spinal deformity

Segmental vessel ligation during anterior spinal surgery has been associated with paraplegia. However, the incidence and risk factors for this devastating complication are debated. We reviewed 346 consecutive paediatric and adolescent patients ranging in age from three to 18 years who underwent surgery for anterior spinal deformity through a thoracic or thoracoabdominal approach, during which 2651 segmental vessels were ligated. There were 173 patients with idiopathic scoliosis, 80 with congenital scoliosis or kyphosis, 43 with neuromuscular and 31 with syndromic scoliosis, 12 with a scoliosis associated with intraspinal abnormalities, and seven with a kyphosis. There was only one neurological complication, which occurred in a patient with a 127 degrees congenital thoracic scoliosis due to a unilateral unsegmented bar with contralateral hemivertebrae at the same level associated with a thoracic diastematomyelia and tethered cord. This patient was operated upon early in the series, when intra-operative spinal cord monitoring was not available. Intra-operative spinal cord monitoring with the use of somatosensory evoked potentials alone or with motor evoked potentials was performed in 331 patients. This showed no evidence of signal change after ligation of the segmental vessels. In our experience, unilateral segmental vessel ligation carries no risk of neurological damage to the spinal cord unless performed in patients with complex congenital spinal deformities occurring primarily in the thoracic spine and associated with intraspinal anomalies at the same level, where the vascular supply to the cord may be abnormal.

The angiosome territories of the spinal cord: exploring the issue of preoperative spinal angiography. Laboratory investigation

OBJECT

The angiosome concept has been the subject of extensive research by the senior author (G.I.T.), but its specific applicability to the spinal cord was hitherto unknown. The aim of this study was to see if the spinal cord vasculature followed the angiosome concept and to review the usefulness of preoperative spinal angiography in surgery for spinal disorders. Spinal cord infarction and permanent paraplegia may result from inadvertent interruption of the artery of Adamkiewicz. Spinal angiography, which may enable avoidance of this catastrophic complication, is still not commonly used.

METHODS

Two fresh cadavers were injected with a gelatin-lead oxide mixture for detailed comparative study of spinal cord vasculature. One cadaver had insignificant vascular disease, whereas the other had extensive aortic atherosclerosis, presenting a unique opportunity for study. After removal from each cadaver, radiographs of the spinal cords were obtained, then photographed, and the vascular territories of the cords were defined.

RESULTS

Four angiosome territories were defined: vertebral, subclavian, posterior intercostal, and lumbar. These vascular territories were joined longitudinally by true anastomotic channels along the anterior and posterior spinal cord. Anastomosis between the anterior and posterior vasculature was poor in the thoracolumbar region. The anterior cord relied on fewer feeder arteries than the posterior, and the anterior thoracolumbar cord depended on the artery of Adamkiewicz for its supply. In chronic aortic disease with intercostal artery occlusion at multiple levels, a rich collateral circulation supporting the spinal cord was found.

CONCLUSIONS

The arterial supply of the spinal cord follows the angiosome concept. The atherosclerotic specimen supports the suggestion that the blood supply is able to adapt to gradual vascular occlusion through development of a collateral circulation. Nevertheless, the spinal cord is susceptible to ischemia when faced with acute vascular occlusion. This includes inadvertent interruption of the artery of Adamkiewicz. The authors recommend the use of preoperative spinal angiography to prevent possible paraplegia in removal of thoracolumbar spinal tumors.

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.

Anterior exposures of the pediatric spine and posterior pedicle screw instrumentation

Treatment of spinal deformities, tumors, and trauma is greatly facilitated by correctly understanding the associated anatomy. Exposure of the spine, whether with a standard posterior dissection or a technically demanding costotransversectomy, facilitates surgical treatment of all disorders. When indicated, posterior instrumentation with pedicle screws allows for maximum rigidity and stability until arthrodesis ensues. Appropriate stepwise screw placement and confirmation of placement with radiographs and triggered electromyograms allows safe use of pedicle screws at all regions of the spine, with no associated morbidity to the patient. This article focuses on the classic approaches used to access the pediatric spine and discusses modern-day pedicle screw instrumentation for spinal pediatric deformity, trauma, or tumors.

Segmental vessel sparing during convex growth arrest surgery--a modified technique

BACKGROUND CONTEXT

Further evidence of the importance of segmental vessel ligation in the development of neurological complications has been recently published. The more levels the ligation encompasses, the higher the risk of spinal cord damage. Therefore, caution should be taken when several segmental arteries are to be ligated in the clinical setting.

PURPOSE

To prevent ligation of segmental vessels during convex growth arrest surgery and thus decrease the risk of spinal cord ischemia and neurological injury.

STUDY DESIGN

A report of a modified technique of convex growth arrest surgery used in two consecutive patients in our unit.

METHODS

In two consecutive patients the segmental vessels were mobilized, elevated, and protected by using surgical slings. The rib graft was then slid beneath the elevated vessels into the prepared vertebral body channel and punched into place. The pleura then closed over the rib graft and spared vessels.

RESULTS

Three of the five segmental vessels in the first patient were spared. All five segmental vessels were spared in the second patient. No neurological complications occurred.

CONCLUSION

We report a straightforward technique, which obviates the need for segmental vessel ligation, and therefore decreases the risk of neurological injury in an already high-risk group.

Avoiding neurologic complications following ligation of the segmental vessels during anterior instrumentation of the thoracolumbar spine

STUDY DESIGN

A retrospective evaluation of anterior instrumentation of the vertebral bodies in the thoracolumbar spine.

OBJECTIVE

To evaluate the possibility of preserving the segmental vessels following anterior instrumentation.

SUMMARY OF BACKGROUND DATA

Occlusion of the segmental vessels, routinely performed during anterior spine instrumentation, might cause neurologic injury secondary to cord ischemia.

METHODS

The medical data of 29 patients following anterior instrumentation of the vertebral bodies at the thoracolumbar spine were reviewed. All underwent surgery recently when we decided to preserve the segmental vessels whenever possible. We sought the reasons that enabled us to do so regarding age, gender, underlying pathology, surgical technique, operation duration, instrumentation type and size, and location in the vertebral body.

RESULTS

In only 7 patients, fused between T10 and L5, were we able to preserve the segmental vessels. All were instrumented with one 6.25-7-mm wide screw in each vertebral body connected by one rod, approximately half the screws above and half below the segmental vessels. In 22 patients, we were unable to preserve the vessels due to the need to insert 2 screws or a large threaded wide vertebral cage into each vertebra.

CONCLUSIONS

There is adequate space anteriorly in the vertebral body, above and below the segmental vessels, for the insertion of one screw, even with staples.

Spinal cord monitoring in scoliosis surgery using an epidural electrode. Results of a prospective, consecutive series of 191 cases

STUDY DESIGN

Retrospective analysis of a prospectively accrued series of 191 consecutive patients who underwent intraoperative neurophysiologic monitoring during scoliosis corrective surgery.

OBJECTIVES

To compare the monitoring outcome of idiopathic and neuromuscular scoliosis. To demonstrate the usefulness of the epidural electrode. To report sensitivity and specificity of the monitoring method employed at a single institution.

SUMMARY OF BACKGROUND DATA

Reports in the literature emphasized the difficulty to obtain data in neuromuscular patients. Multimodality spinal cord monitoring has been recommended. Despite their still debated composition, neurogenic motor-evoked potentials have proven their validity in clinical practice.

METHODS

Somatosensory and neurogenic evoked potentials were attempted in all patients presenting for scoliosis correction between 1999 and 2005. Study patients were divided into 3 groups: group 1, idiopathic; group 2, neuromuscular; and group 3, miscellaneous origins.

RESULTS

The use of the epidural electrode demonstrated significant usefulness in the ability of monitoring otherwise nonmonitored patients, especially in group 2. Inability to obtain any evoked potentials occurred in 4 cases (2.1%). Five cases were found to be true positives. An adapted and rapid intervention permitted to avoid new postoperative deficit in all cases. There was no instance of false-negative data. The overall method sensitivity was 100%, and specificity was 52.69%.

CONCLUSIONS

The use of a single epidural electrode allowing somatosensory evoked potentials recording and spinal cord stimulation alternately is a safe and valid method of intraoperative monitoring.

Vascular injury and complication in neurosurgical spine surgery

Vascular injury is an uncommon, but not rare complication of spine surgery. The consequence of vascular injury may be quite devastating, but its incidence can be reduced by understanding the mechanisms of injury. Properly managing vascular injury can reduce mortality and morbidity of patients. A review of the literature was conducted to provide an update on the etiology and management of vascular injury and complication in neurosurgical spine surgery. The vascular injuries were categorized according to each surgical procedure responsible for the injury, i.e., anterior screw fixation of the odontoid fracture, anterior cervical spine surgery, posterior C1-2 arthrodesis, posterior cervical spine surgery, anterolateral approach for thoracolumbar spine fracture, posterior thoracic spine surgery, scoliosis surgery, anterior lumbar interbody fusion (ALIF), lumbar disc arthroplasty, lumbar discectomy, and posterior lumbar spine surgery. The incidence, mechanisms of injury, and reparative measures were discussed for each surgical procedure. Detailed coverage was especially given to vascular injury associated with ALIF, which may have been underestimated. The accumulation of anatomical knowledge and advanced imaging studies has made complex spine surgery safer and more reliable. It is not clear, however, whether the incidence of vascular injury has been reduced significantly in all procedures of spine surgery. Emerging new techniques, such as microendoscopic discectomy and lumbar disc arthroplasty, seem to be promising, but we need to keep in mind their safety issues, including vascular injury and complication.

Reduction of vertebral blood flow by segmental vessel occlusion: an intraoperative study using laser Doppler flowmetry

STUDY DESIGN

During anterior spinal surgery, vertebral perfusion was assessed by laser Doppler flowmetry. Blood flow changes were assessed after unilateral ligation and contralateral compression of the segmental vessels.

OBJECTIVE

To assess the influence of unilateral and bilateral segmental vessel occlusion on vertebral blood flow.

SUMMARY OF BACKGROUND DATA

During anterior spinal surgery, segmental vessels are frequently being ligated. The reduced blood supply to the vertebrae may impair intervertebral fusion, and the decreased spinal cord perfusion may lead to ischemic myelopathy. To our knowledge, this is the first in vivo study to investigate vertebral blood flow. METHODS.: There were 10 patients who underwent anterior release for adult idiopathic scoliosis (n = 6), Scheuermann disease (n = 3), and posttraumatic kyphosis (n = 1). A high-power laser Doppler flowmeter was used to assess vertebral blood flow. Measurements were performed in 19 thoracic and 4 lumbar vertebrae (n = 23) after unilateral segmental vessel ligation and additional temporary digital compression of the contralateral vessels.

RESULTS

Initial mean blood flow was 49.1 +/- 27.6 arbitrary units, and all signals were pulsatile. The blood flow decreased by a mean of 8% after unilateral ligation of the segmental vessels. With additional compression of the contralateral vessels, the signal heights decreased significantly by 54% (mean 18.3 +/- 7.8 arbitrary units, P = 0.00003), and a loss of the pulsatile pattern was observed in 75% of the vertebrae. On release of digital compression, the signal height as well as the pulsatility promptly returned.

CONCLUSIONS

Unilateral ligation of segmental vessels led only to a slight decrease of the vertebral blood flow. Future studies may show whether sparing the segmental vessels during anterior fusion enhances bone graft incorporation, thus decreasing the rate of pseudarthrosis. According to clinical data, the risk of neurologic injury through unilateral ligation is negligible. Bilateral segmental vessel occlusion markedly reduced vertebral bloodflow. Therefore, when treating patients with a higher neurologic risk or in revision cases, the surgeon should always consider sparing the segmental vessels.

[Complications of surgical treatment of spinal deformities: a prospective multicentric study of 3311 patients]

PURPOSE OF THE STUDY

The incidence of complications secondary to surgical treatment of spinal deformations remains imprecise. The purpose of this prospective multicentric observational study was to assess the incidence of intra- and postoperative complications secondary to this type of surgery to detail the observed complications and to identify favoring factors.

MATERIAL AND METHODS

For this study, we included 3311 patients who underwent surgery during a 12-month period for spinal deformation, defined as idiopathic or secondary scoliosis or kyphosis, irrespective of the localization, severity, or type of surgery performed. Four main categories of complications were studied: general, infectious, neurological, and mechanical. Pre- and intraoperative variables recorded were: epidemiological and morphological data, history of surgery for the same spinal deformation, comorbid conditions, type of deformation treated (nature, anatomic localization, severity, reducibility), type of surgery performed (approach, duration of the operation), operative blood loss, extent and localization of the fusion, associated neurological release, vertebral osteotomy or not, type of graft used. Two types of analysis were performed. The first was a descriptive analysis to detail the overall incidence of complications and the incidence of each of the four main categories. The second was a multivariate analysis designed to determine factors significantly associated with complication occurrence.

RESULTS

Mean age of the cohort was 27 +/- 18 years; 6.8% of the patients had had a prior operation for the spinal deformation. The deformation was scoliosis in 90% (mean angle 56 +/- 20 degrees) and kyphosis in 10% (mean angle 47 +/- 23 degrees). An isolated posterior approach was used for 72.5% of patients, an isolated anterior approach for 6.4%, and a combined anteroposterior approach for 21.1%. Seven hundred four patients (21.3%) had one or more complications (850 complications) during or shortly after their operation. The incidences of general, infectious, mechanical and neurological complications were: 5.7%, 4.7%, 11.5%, and 1.8% respectively. Globally, considering all types of complications, the following factors were found to be significantly associated with complication occurrence: patient age, ASA score, extent of the fusion, presence of vertebral osteotomy, inclusion of the sacrum in the arthrodesis, and initial angle of the treated deformation. For patients with scoliosis, the following factors were significantly associated with a secondary central neurological disorder: initial angle of the deformation, use of vertebral osteotomy, type of curvature with greater risk for thoracic curvatures and double thoracic and lumbar curvatures.

CONCLUSION

This work enabled us to determine the overall rate of complications after surgical treatment of spinal deformations. Certain risk factors related with complication occurrence were identified, but the heterogeneous nature of the population and the methodology used to identify these factors only allowed detection of trends. A future study by etiological group or focusing on specific complications should allow a more precise analysis of these risk factors. This overall rate of complications should be used to better inform patients and their family about the risks of this type of surgery.

Change pattern of somatosensory-evoked potentials after occlusion of segmental vessels: possible indicator for spinal cord ischemia

Paraplegia was reported after occlusion of the segmental vessels during anterior spinal surgery. The aim of this study was to investigate the effect of occlusion of the segmental vessels on the somatosensory-evoked potential (SEP) monitoring and analyze its potential risk for cord ischemia. Thirty-one patients with thoracic scoliosis underwent anterior spinal surgery. T5-T11 segmental vessels on the convexity were occluded with microvascular clamps at the point 2 cm from the intravertebra foramen. The SEPs were recorded 5 min before occlusion and 2, 7, 12 and 17 min after occlusion. The SEPs were analyzed with two indices i.e. P40 latency and P40 amplitude. All SEP waveforms recorded during the test were regular and recognizable. Compared to 5 min before occlusion, the P40 latencies at 2 min and 7 min after occlusion significantly increased 3.39% and 2.76% on an average, the P40 amplitudes at 2 min after occlusion significantly declined 26% (peak to peak) or 22% (peak to baseline) on an average (P<0.05). But the changes of SEPs were temporary. The SEPs began to restore at 12 min after occlusion and returned to the pre-occlusion level at 17 min after occlusion. No neurologic complications occurred in all patients after surgery. These results suggest that SEP is a possible indicator for ischemia of the spinal cord which is a dynamic course and cannot be considered an "all-or-none" phenomenon. Without the factors such as developmental deformities of the spinal cord, vascular variation and potential cord ischemia, occlusion of the segmental vessels would be safe during the anterior spinal surgery.

Cord monitoring changes and segmental vessel ligation in the "at risk" cord during anterior spinal deformity surgery

STUDY DESIGN

Retrospective analysis of all cases of anterior spinal deformity surgery that had intraoperative spinal cord monitoring (somatosensory-evoked potentials, SSEPs).

OBJECTIVES

The prime purpose of this study was to determine the incidence of significant SSEP changes in patients undergoing anterior spinal deformity surgery. A secondary objective was to ascertain if patients with "cords at risk" were more likely to produce significant intraoperative SSEP changes and what proportion of these changes resulted in postoperative neurological deficit.

SUMMARY OF BACKGROUND DATA

There is anecdotal evidence to suggest that patients with intraspinal abnormalities are at greater risk of postoperative neurological deficit after spinal deformity surgery. To date, there have been no studies detailing this risk and how it relates to the type of surgery performed. This is a question of increasing relevance with the modern trend towards more anterior scoliosis correction and instrumentation. Recent reports have suggested a low incidence of neurological complication with anterior deformity procedures. There is controversy as to whether SSEP monitoring is required for these anterior procedures and whether soft clamping of segmental vessels before their division is a necessary precaution.

METHOD

This study is a chart review of all patients who had an anterior deformity operation between 1990 and 2001. Those patients who had a complete data set (preoperative magnetic resonance imaging scan, patient and procedural documentation, and adequate intraoperative SSEP traces) were included in this study. A significant SSEP change was correlated with the type of procedure performed, whether that patient had a "cord at risk" (CAR) and the degree of postoperative neurological deficit if present.

RESULTS

During the study period, 871 patients underwent elective anterior spinal deformity surgery. Ninety five (11%) patients had intraspinal abnormalities on magnetic resonance imaging. From this group, 27 (3%) were termed CAR. Twenty six (3%) patients had significant change in the intraoperative SSEP monitoring. Seventeen (2% total) occurred in the CAR group and nine (1% of total) in the normal cord group. There were five patients (0.6%) with significant postoperative neurological deficits, four (0.5%) in the CAR group, and one (0.1%) in the normal cord group. These patients had also demonstrated changes in their SSEPs. The sensitivity of SSEP monitoring for the whole series was 100%, specificity 97.5%, the positive predictive value was 19% and the negative predictive value was 100%. The CAR group was significantly more likely to have significant SSEP changes during any operation and was more likely to have postoperative paresis.

CONCLUSION

Patients with identified cords at risk should undergo spinal cord monitoring (SSEP) if they undergo anterior spinal deformity surgery. Soft clamping of segmental vessels is indicated with cord monitoring to prevent the risk of postoperative neurological sequelae.

Video-assisted thoracoscopic surgery: the Cincinnati experience

Video-assisted thoracoscopic surgery is an alternative to open thoracotomy. We analyzed our experience during a consecutive series of 100 patients who had this procedure and who were available for study at 3-year followup. Video-assisted thoracoscopic surgery was done on patients with the following diagnoses: idiopathic scoliosis (n = 49), neuromuscular spinal deformity (n = 15), Scheuermann kyphosis (n = 15), congenital and infantile scoliosis (n = 5), neurofibromatosis (n = 5), Marfan (n = 1), postradiation scoliosis (n = 1), and repair of pseudoarthrosis (n = 1). Four patients had excision of the first rib to treat thoracic outlet syndrome. One patient had excision of an intrathoracic neurofibroma and one a benign rib tumor. One had anterior arthrodesis after fracture-dislocation of the thoracic spine and another had anterior fusion for vertebral osteomyelitis. The average operative time for the thoracoscopic anterior release with discectomy and arthrodesis was 253 minutes. The average number of discs excised was 8. Final postoperative scoliosis and kyphosis corrections were 68% and 90%, respectively. Complications related to thoracoscopy occurred in eight patients. Video-assisted thoracoscopic surgery provides a safe and effective alternative to open thoracotomy in the treatment of thoracic pediatric spinal deformities.

Effect of segmental artery ligation on the blood supply of the thoracic spinal cord during anterior spinal surgery: a quantitative histomorphological fresh cadaver study

STUDY DESIGN

Human cadaver quantitative morphometric analysis of the blood vessels in the spinal cord after ligation of segmental arteries.

OBJECTIVES

To investigate the effect of ligation of segmental arteries on the quantity and density of the blood vessels in the spinal cord.

SUMMARY OF BACKGROUND DATA

Ligation of segmental arteries is often used in the anterior approach for correction scoliosis. However, whether or not segmental artery ligation is liable to deny the spinal cord an adequate blood supply, thus leading to paraplegia, still remains controversial.

METHODS

Eleven fresh cadavers were divided into control, unilateral, and bilateral groups. For the unilateral and bilateral groups, 5 segmental vertebral arteries (T7-T11) were ligated unilaterally and bilaterally, respectively. Then, the number and density of blood vessels at different levels in the 3 groups were measured.

RESULTS

Compared to that of the corresponding level in the control group, the number of blood vessels at T5 to L1 all decreased in the ligation groups. And significant differences were found at T8 (82.80 +/- 16.36), T10 (77.80 +/- 19.80), and T11 (99.20 +/- 14.85) levels, compared to those of the corresponding levels in the control group: T8 (175.80 +/- 8. 31), T9 (176.40 +/- 32. 33), T10 (171.40 +/- 9. 73), and T11 (189.20 +/- 15. 92). Further decrease was found at each corresponding level in the bilateral group, and significant differences were found at T8 (65.80 +/- 15.55), T9 (24.80 +/- 13.43), T10 (0), T11 (0), and T12 (0) levels. Similar results were obtained with regard to the density of blood vessels. Significant differences were found at T11 (1.246 +/- 0.112) and L1 (1.349 +/- 0.109) in the unilateral group, and T9 (0.260 +/- 0.088), T10 (0), T11 (0), T12 (0), and L1 (0.147 +/- 0.117) in the bilateral group compared to those of the corresponding levels in the control group: T9 (1.810 +/- 0.202), T10 (1.833 +/- 0.175), T11 (2.308 +/- 0.335), T12 (2.510 +/- 0.617), and L1 (2.193 +/- 0.033).

CONCLUSIONS

This study suggests that the more levels the ligation encompasses, the higher the risk of spinal cord damage. Therefore, caution should be taken when several segmental arteries are to be ligated in the clinical setting. What is more, bilateral ligation, which is worse than unilateral ligation, can lead to a significant decrease in the number and density of blood vessels of the spinal.

Neurological deficit from a purely vascular etiology after unilateral vessel ligation during anterior thoracolumbar fusion of the spine

STUDY DESIGN

Comprehensive analysis of patient records who underwent anterior approach to the thoracolumbar spine at a single institution.

OBJECTIVES

To report on neurologic deficit from a purely vascular injury to the spinal cord occurring after unilateral anterior thoracolumbar spinal surgery that did not involve additional correction or other etiologies.

SUMMARY OF BACKGROUND DATA

The largest study in the literature regarding the risks of neurovascular deficit during anterior exposure of the thoracolumbar spine reports that there exists no risk with unilateral ligature of the segmental arteries.

METHODS

The records and operative notes of 265 consecutive patients were reviewed. All adult neurologically intact patients, average age 40.2 years (range 18-85 years) who have had surgery between 1985 and 2002 that involved anterior approach to the thoracic spine were included. Segmental arteries were ligated midbody, away from the foramen and the aorta. Seventy-two percent of the approaches were left-sided. An average of 5.1 unilateral segmental artery ligations were performed per procedure.

RESULTS

Two patients out of 265 had major neurologic deficit after anterior thoracolumbar approach. Both patients had staged procedures: posterior spinal fusion then anterior spinal fusion to the thoracolumbar spine. One deficit occurred immediately after surgery and the other occurred 24 hours after surgery. No additional corrective maneuvers were performed; neither patient was hypotensive, nor did they experience blood loss anemia and their postoperative computed tomography myelogram study was normal.

CONCLUSION

Neurologic deficit after anterior exposure to the thoracolumbar spine occurred in 0.75% of patients in this study exclusively from unilateral left-sided ligation of the T10-T12 segmental vessels. Both patients had common risks of prior kyphosis correction, revision surgery and left-sided approach.

Hypotension-induced loss of intraoperative monitoring data during surgical correction of scheuermann kyphosis: a case report

STUDY DESIGN

Presentation of a case report of Scheuermann kyphosis surgical correction.

OBJECTIVE

To describe a scenario where both neurogenic mixed evoked potentials and somatosensory-evoked potentials were lost due solely to hypotension before any correction of a kyphotic spinal deformity was performed.

SUMMARY OF BACKGROUND DATA

Multimodality intraoperative neurophysiologic monitoring of the spinal cord has become widely utilized during surgical correction of scoliotic and kyphotic deformities. Most spinal surgeries also benefit from a state of hypotension to minimize blood loss, but unchecked and persistent hypotension may lead to inadequate perfusion to the spinal cord, resulting in spinal cord dysfunction noted by diminution of neuromonitoring data.

METHODS

An 18-year-old boy with a 95 degrees Scheuermann kyphosis underwent a posterior spinal fusion for correction of his deformity. Intraoperative neurophysiologic monitoring consisting of neurogenic mixed evoked potentials and somatosensory-evoked potentials were performed throughout surgery.

RESULTS

After placement of segmental pedicle screw fixation points and multiple osteotomies, before any instrumented correction of the deformity, all lower extremity neuromonitoring data were acutely lost. The surgeon was immediately warned of the data loss, with the mean arterial pressure noted to be 50 mm Hg. The mean arterial pressure was raised with the use of epinephrine bolus and dopamine infusion. Subsequently, all lower extremity neuromonitoring data returned. A Stagnara wake-up test was performed, which the patient passed, and the surgical correction was performed with his pressure maintained on a dopamine infusion. He awakened without neurologic deficits and had an uneventful recovery.

CONCLUSIONS

Although a state of mild hypotension may be beneficial to limit blood loss during spinal deformity corrective surgery, acute and/or prolonged hypotension may jeopardize spinal cord vascularity and should be avoided especially during surgical treatment of high-risk deformities such as kyphosis. Early warning by multimodality physiologic neuromonitoring appears to be a useful method to alert surgeons of the potentially devastating problem of hypotension-induced spinal cord dysfunction and allows immediate corrective actions.

Vertebral body resection

Vertebral body resection for locally advanced lung cancer can be performed with acceptable morbidity and mortality rates, and with improved long-term survival, when combined with chemotherapy and radiation. A consensus has not been reached on either the optimal extent of vertebral resection or the optimal treatment regimen. Should total vertebrectomies be the standard of care for all patients, even those with minimal spine involvement? Can the extended operative times and multiple incisions and anatomic limitations that place some of the mediastinal organs at risk be justified for potential improvement in local control, or are the quicker and potentially safer endolesional resections appropriate for these tumors? Is local control, and ultimately survival, improved when additional chemotherapy and radiation therapy is given up front, or is an uninterrupted course of a higher dose of concurrent chemotherapy and radiation therapy following surgery preferred? Ideally, these questions will be answered by means of prospective randomized trials; however, because of the small number of patients who actually present with vertebral body involvement by lung cancer, physicians may have to rely on phase 2 studies and series reports from high-volume institutions to guide their treatment algorithms in the future.

The Efficacy of Anterior Spine Exposure by An Orthopedic Surgeon

This retrospective study was designed to document the incidence and types of perioperative complications that occurred with anterior spinal fusion surgery performed solely by an orthopedic spine surgeon. This study is contrasted to previous studies that document complications from anterior approaches performed by an orthopedic surgeon with the assistance of a general or a vascular surgeon. Specifically, the procedures included thoracotomies, thoracolumbar retroperitoneal, and lumbosacral approaches. Our sample consisted of 450 patients who underwent anterior spinal fusion between levels T1 and S1, from 1985 to 1997. Patient and surgery characteristics included age, sex, diagnosis, levels of fusion, blood loss, operative time, hospitalization time, complications, American Society of Anesthesiologists state, assessment of risk factors, previous surgery, and surgical approach used. Average follow-up was 41.69 months, with a minimum of 12 months and a maximum of 132 months. Our results indicated that anterior procedures performed solely by our senior orthopedic surgeon had a lower incidence of complications, less blood loss, and shorter operative time than anterior procedures performed by an orthopedic surgeon and a vascular or a general surgeon. Our findings suggest that the anterior spinal exposure is a safe approach that may be performed solely by a spinal surgeon who is knowledgeable and experienced.

Thoracoscopic discectomy and fusion in an animal model: safe and effective when segmental blood vessels are spared

STUDY DESIGN

Disc-endplate excision and spine fusion were compared in animals randomly assigned to segmental vessel-spared and segmental vessel-ligated groups in an in vivo goat model of anterior spine discectomy and fusion using thoracoscopic techniques.

OBJECTIVES

To compare safety and completeness of disc and endplate excision, and to perform a histologic and biomechanical comparison between fusion masses when the segmental vessels are spared and when they are ligated using thoracoscopic techniques. SUMMARY OFF BACKGROUND DATA: Because thoracoscopy is relatively new and technically demanding, many surgeons ligate the segmental blood vessels to enhance spine exposure and limit the risk of injury during discectomy and fusion. Although rare, spinal cord compromise secondary to segmental vessel ligation has been reported.

METHODS

This study was divided into two phases. In Phase 1, 10 mature goats were randomly assigned to either the segmental vessel-ligated or the segmental vessel-spared group. Disc and endplate excision was performed at six consecutive thoracic levels in each animal (30 levels per group). The animals were killed, and the depth of disc excision was measured in the transverse and sagittal planes. The vertebral bodies then were separated through the disc space; photographic images of the endplates were digitized, and the area of endplate excision was calculated. In Phase 2, 12 mature goats were randomly assigned to the segmental vessel-ligated or vessel-spared group, and five noncontiguous thoracic segments were fused using autologous iliac crest graft. At 4 months the animals were killed, and the spines were harvested. At each disc level, the three-dimensional rotational and translational motions were analyzed and histomorphometric analysis was performed.

RESULTS

Phase 1: Each animal survived the operative procedure, and no surgical complications occurred. No difference was found between vessel-ligated and vessel-spared groups in operative time (21.8 vs 22.7 minutes per disc), blood loss (97 vs 159 mL), or transverse (81% vs 74%) or sagittal (85% vs 85%) disc excision. The total area of endplate excision was 70% in the vessel-ligated group and 67% in the vessel-spared group (P > 0.1). Phase 2: Biomechanical testing demonstrated no difference in stiffness of the fused segments between the two groups in flexion-extension or axial rotation. However, greater flexibility in lateral bending was found in the specimens whose vessels were ligated (P < 0.05). The percentage of trabecular bone volume was similar between the two groups.

CONCLUSIONS

The segmental vessels in the thoracic spine can be effectively spared without injury during disc excision and fusion. Although slightly more disc area was excised with ligation of the vessels, this was not statistically significant, and the fusion mass was similar between the two groups. Sparing the segmental vessels may provide blood supply that aids fusion mass, and the result may be greater spine stiffness in the coronal plane. Sparing the segmental vessels during thoracoscopic anterior disc excision and fusion can be safe. It should be considered in patients with a high risk for neurologic injury because of decreased spinal cord perfusion in revision surgery, severe kyphosis, congenital anomalies. Because the neurologic risk of vessel ligation has not been clearly established for idiopathic scoliosis, the surgeon will have to consider the risk-benefit ratio of adopting these methods when deciding not to ligate vessels in these patients.

En bloc resection of non-small cell lung cancer invading the thoracic inlet and intervertebral foramina

OBJECTIVE

In patients with non-small cell lung cancer invading the thoracic inlet, the transcervical approach does not permit removal of tumor in the intervertebral foramina. We report a variant that lifts this limitation.

METHODS

Through the transcervical approach, resectability was assessed and tumor-bearing structures were removed, leaving tumor-free margins. Standard upper lobectomy was performed, leaving the lobe in place. A posterior midline approach was used for multilevel unilateral laminectomy, nerve root division inside the spinal canal, and vertebral body division along the midline. The tumor was removed en bloc with the lung, ribs, and vessels through the posterior incision. Fixation of the spine was performed. Medical charts of patients treated with this technique between October 1994 and April 2001 were reviewed retrospectively.

RESULTS

Seventeen patients (mean age 45 years) were treated. Resection of the upper lobe and T1 root was done in all 17 cases; 3- and 4-level hemivertebrectomies were done in 13 and 3 cases, respectively; 2-level total vertebral body resection and 2-level hemivertebrectomy were done in 1 case; and resections of the phrenic nerve and subclavian artery were done in 7 and 6 patients, respectively. There were no perioperative deaths or residual neurologic impairments. Postoperative complications were pneumonia (n = 6), cerebrospinal fluid leakage (n = 1), wound breakdown (n = 1), and bleeding necessitating reoperation (n = 1). The overall 3- and 5-year survivals were 39% and 20%, respectively.

CONCLUSIONS

Non-small cell lung cancers invading the thoracic inlet and intervertebral foramina can be removed completely through a combined anterior transcervical and posterior midline approach, with good results.

Long multiple struts for severe kyphosis

The treatment of severe structural kyphosis poses a difficult problem. The use of an anterior fusion has proven to be an integral part of the surgical treatment of any kyphosis. In addition, the use of multiple struts has helped solve the treatment problem in severe kyphosis. The use of multiple struts and the role of vascularized grafts, technical details, complications, and errors and how to prevent them are discussed in the current study.

Transient paraparesis: a complication of the surgical management of Scheuermann's kyphosis secondary to thoracic stenosis

STUDY DESIGN

Transient paraparesis during the operative management of a 16-year-old patient with Scheuermann's kyphosis secondary to thoracic stenosis is reported.

OBJECTIVE

To describe a treatable cause for paraparesis in a patient with Scheuermann's kyphosis undergoing surgical treatment.

SUMMARY OF BACKGROUND DATA

Cord injury in the surgical treatment of Scheuermann's kyphosis is a rare event, yet it is felt to be more common in the surgical correction of kyphosis than in surgery for scoliosis. Suggested etiologies have included vascular insufficiency, hypotension, direct mechanical trauma, and neural element stretch. Concomitant thoracic spinal stenosis predisposing to neurologic injury during surgical manipulation has not been reported.

METHODS

A 16-year-old boy with progressive Scheuermann's kyphosis measuring 80 degrees from T7 to T12 underwent an anteroposterior spinal fusion with somatosensory-evoked potential monitoring and wake-up tests. During the instrumentation posteriorly, somatosensory-evoked potential monitoring became markedly abnormal. This was followed by a wake-up test that demonstrated the patient's inability to move either of his lower extremities. All instrumentation was removed. The patient had recovered neurologic function by the time he reached the recovery room. A computed tomography myelogram was performed on the third postoperative day, which demonstrated severe thoracic stenosis from T8 to T10. The patient was returned to the operating room 1 week later to undergo a posterior laminectomy from T7 to T11 and instrumented fusion from T5 to L2. Somatosensory-evoked potential monitoring was stable throughout this procedure, and the wake-up test was normal.

RESULTS

The patient's postoperative course and subsequent 2-year follow-up period were unremarkable. He progressed to clinical and radiographic union and maintained a normal lower extremity neurologic examination.

CONCLUSIONS

A treatable cause for paraparesis secondary to the surgical treatment of Scheuermann's kyphosis is presented. The author currently obtains a thoracic magnetic resonance image (MRI) before the surgical correction of any patients with Scheuermann's kyphosis.

One-stage approach for retroperitoneal and mediastinal metastatic testicular tumor resection

BACKGROUND

Eight percent of nonseminomatous germ cell tumors of the testis are associated with postchemotherapy residual masses in both the retroperitoneum and the posterior mediastinum. We describe a transabdominal transdiaphragmatic approach that allows simultaneous resection of these masses.

METHODS

After standard retroperitoneal lymph node dissection through a midline laparotomy, an incision parallel to the right crus of the diaphragm was made and extended anteriorly through the muscular portion. Excellent exposure of the lower posterior mediastinum was obtained. Masses located higher than vertebra T8 were resected by extending this incision anteriorly and performing a partial sternal division. A complete median sternotomy can be done to allow subcarinal dissection, as well as pulmonary or anterior mediastinal mass resection.

RESULTS

Between 1993 and 1999, 18 patients had simultaneous resection of retroperitoneal and posterior mediastinal masses with this approach. There were no perioperative deaths; 3 patients had minor postoperative complications. After a median follow-up of 3.2 years, the overall 5-year survival rate was 92%, and the 5-year disease-free survival rate was 87%.

CONCLUSIONS

The transdiaphragmatic approach to the posterior mediastinum is less aggressive than the thoracoabdominal approach. It is safe and effective for simultaneous resection of postchemotherapy testicular nonseminomatous germ cell tumors located in the retroperitoneum and posterior mediastinum.

Major intraoperative neurologic deficits in pediatric and adult spinal deformity patients. Incidence and etiology at one institution

STUDY DESIGN

A retrospective study of 1,090 patients undergoing corrective spinal deformity surgery for scoliosis (n = 920), kyphosis (n = 77), or a combination of the two (n = 93) at one institution.

OBJECTIVES

To ascertain the etiologies and incidence of neurologic deficits occurring at the time of surgery.

SUMMARY OF BACKGROUND DATA

Potential etiologies of intraoperative neurologic deficits include cord compression, overdistraction, purely vascular, or a combination.

METHODS

The study group included only patients with useful function of their lower extremities and normal bowel and bladder control, and patients whose surgeries were in spinal cord territory as opposed to purely cauda equina territory.

RESULTS

There were four major neurologic deficits that occurred during surgery. Three of the four deficits were purely vascular in etiology. The fourth may have had a vascular and mechanical etiology. All four patients had anterior and posterior surgery with harvesting of the unilateral convex segmental vessels, and each had a component of hyperkyphosis, as well as intraoperative controlled hypotension. All four patients showed marked improvement of motor weakness with time.

CONCLUSIONS

Significant risk factors were combined anterior and posterior surgery (P = 0.009) and hyperkyphosis (P = 0.0006).