Percutaneous biopsy of the cervical spine using CT guidance

Discitis-osteomyelitis: optimizing results of percutaneous sampling

Vertebral discitis-osteomyelitis is an infection of the spine that involves the intervertebral disc and the adjacent vertebral body but may also extend into the paraspinal and epidural soft tissues. If blood cultures and other culture data fail to identify a causative microorganism, percutaneous sampling is indicated to help guide targeted antimicrobial therapy. Despite limited supporting evidence, withholding antimicrobial therapy for up to 2 weeks is recommended to maximize microbiological yield, although literature supporting this recommendation is limited. During the procedure, technical factors that may improve yield include targeting of paraspinal fluid collections or soft tissue abnormalities for sampling, acquiring multiple core samples if possible, and use of larger gauge needles when available. Repeat sampling may be indicated if initial percutaneous biopsy is negative but should be performed no sooner than 72 h after the initial percutaneous biopsy to ensure adequate time for culture results to return.

Transcervical Access for Ultrasound-Guided Biopsy—A Safe Technique to Sample Apical Lung Lesions

Eight patients with apical lobe lung lesions referred for image-guided biopsy where the lesion was abutting the mediastinal or apical pleura, and was visible in ultrasound using a suprasternal–supraclavicular route were consented and subjected to successful ultrasound-guided transcervical biopsy using different routes based on lesion characteristics and location of vital vascular structures—either through the thyroid gland, by the side of the gland lateral to the common carotid artery, or between the thyroid gland and common carotid artery after hydrodissection. Transthyroid access was used in 50% of cases. There were no immediate or long-term complications in any patient over a mean follow-up period of 28.5 months. Sample adequacy was 100%.

Best Practices: CT-Guided Percutaneous Sampling of Vertebral Discitis-Osteomyelitis and Technical Factors Maximizing Biopsy Yield

Vertebral discitis-osteomyelitis is an infection of the intervertebral disk and vertebral bodies that may extend to adjacent paraspinal and epidural soft tissues. Its incidence is increasing, likely because of improved treatments and increased life expectancy for patients with predisposing chronic disease and increased rates of IV drug use and intravascular intervention. Because blood cultures are frequently negative in patients with vertebral discitis-osteomyelitis, biopsy is often indicated to identify a causative microorganism for targeted antimicrobial therapy. The reported yield of CT-guided percutaneous sampling is 31-91%, which is lower than the reported yield of open biopsy of 76-91%. However, the less invasive approach may be favored given its relative safety and low cost. If paravertebral fluid collections are present, CT-guided aspiration should be performed. If aspiration is unsuccessful or no paravertebral fluid collections are present, CT-guided percutaneous biopsy should be performed, considering technical factors (e.g., anatomic approach, needle selection, and needle angulation) that may improve microbiologic yield. Although antimicrobial therapy should be withheld for 1-2 weeks before biopsy if clinically feasible, biopsy may still be performed without stopping antimicrobial therapy if needed. Because of the importance of targeted antimicrobial therapy, repeat biopsy should be considered after 72 hours if initial biopsy does not identify a pathogen.

Transnasal Endoscopic Biopsy Approach to Atlas Tumor with X-ray Assisted and Related Radiographic Measure

OBJECTIVE

To develop an endoscopic transnasal approach to atlas tumors and study its practicability.

METHODS

This article comprises two components: an illustrative case report and observational data on 50 volunteers. As to the case report, a 34 year old man presented with occipital pain for more than 3 months and underwent systematic investigation in Qilu Hospital of Shandong University. CT and MRI scans showed bony destruction in the craniovertebral junction (CVJ) suggestive of tumor. Via an endoscopic transnasal approach to the suspected atlas tumor through the inferior nasal meatus, a Gallini biopsy needle was used to obtain tissue for examination. The procedure was performed endoscopically with double orientation X-ray guidance and coaxial technology after establishing the shortest distance for the biopsy track and range of target tissue and was assisted by manual palpation. As to the observational data, 50 volunteers underwent atlas-related morphometric image measurement using gemstone CT equipment. Biopsy track angles, range for biopsy of the atlas and biopsy track distances were measured by a blinded operator on CT images.

RESULTS

CASE REPORT

pathological examination of the biopsy resulted in diagnosis of a chordoma. There were no complications such as bleeding, infection or spinal cord injury. One month later, the patient underwent tumor resection and reconstruction in other hospital and the diagnosis of chordoma was confirmed by pathological examination of the resected specimen. Observational data: measurements obtained from CT scans of the 50 volunteers were as follows. Biopsy track angles: mean leaning inside angle 3.53° ± 0.39° and mean posterior slope angle 13.05° ± 1.39°. Range for atlas biopsy: transverse diameter 11.84 ± 1.24 mm and longitudinal diameter 9.67 ± 0.90 mm. Biopsy track distances: from atlas to nostril, and to anterior and posterior edges of the inferior turbinate mucosa were 94.52 ± 5.03 mm, 78.21 ± 4.63 mm, and 33.51 ± 3.13 mm, respectively.

CONCLUSIONS

An endoscopic transnasal approach enables biopsy and diagnosis of tumors in the anterior arch of the atlas. Relevant measurements were obtained by assessing CT scans of 50 volunteers to assist operators to determine the effective and safe range for transnasal atlas biopsy.

CT-guided Cervical Bone Biopsy in 43 Patients: Diagnostic Yield and Safety at Two Large Tertiary Care Hospitals

RATIONALE AND OBJECTIVES

The cervical spine is a high-risk area for percutaneous biopsy compared to the thoracic and lumbar regions. Biopsy of the cervical spine is less commonly undertaken, and previously published series on diagnostic yield and safety of cervical spine biopsy have been limited to 12 patients or less. The purpose of our study is to further define the diagnostic yield of computed tomography (CT)-guided biopsy for bony lesions identified in the cervical spine, by combining data from two large tertiary care referral centers.

METHODS

A retrospective review of an imaging database was performed to identify all percutaneous CT-guided biopsies of the cervical spine performed at two tertiary care hospitals from 2010 to 2015. Core biopsies were obtained whenever possible and supplemented with fine-needle aspiration in some cases. Histopathologic results of the biopsy were recorded, as were changes in subsequent management, need for repeat biopsy, and complications.

RESULTS

Forty-three patients underwent CT-guided biopsy of the cervical spine. Sufficient tissue for histopathologic analysis was obtained in 41 out of 43 cases, for a yield of 95%. One case was false-negative and one was deemed insufficient by the pathologist for diagnostic purposes; in both of these cases, only a fine-needle aspiration was obtained. There were no immediate or delayed complications.

CONCLUSIONS

Percutaneous biopsy of the cervical spine is a safe and high-yield method of obtaining a tissue diagnosis when performed under image guidance with CT.

Paediatric musculoskeletal interventional radiology

Interventional radiology technique is now well established and widely used in the adult population. Through minimally invasive procedures, it increasingly replaces surgical interventions that involve higher percentages of invasiveness and, consequently, of morbidity and mortality. For these advantageous reasons, interventional radiology in recent years has spread to the paediatric age as well. The aim of this study was to review the literature on the development, use and perspectives of these procedures in the paediatric musculoskeletal field. Several topics are covered: osteomuscle neoplastic malignant and benign pathologies treated with invasive diagnostic and/or therapeutic procedures such as radiofrequency ablation in the osteoid osteoma; invasive and non-invasive procedures in vascular malformations; treatment of aneurysmal bone cysts; and role of interventional radiology in paediatric inflammatory and rheumatic inflammations. The positive results that have been generated with interventional radiology procedures in the paediatric field highly encourage both the development of new ad hoc materials, obviously adapted to young patients, as well as the improvement of such techniques, in consideration of the fact that childrens' pathologies do not always correspond to those of adults. In conclusion, as these interventional procedures have proven to be less invasive, with lower morbidity and mortality rates as well, they are becoming a viable and valid alternative to surgery in the paediatric population.

Computed Tomography-Guided Biopsy for Potts Disease: An Institutional Experience from an Endemic Developing Country

Study Design

A retrospective chart review.

Purpose

In endemic resource poor countries like Pakistan, most patients are diagnosed and treated for Potts disease on clinical and radiological grounds without a routine biopsy. The purpose of this study was to evaluate the use and effect of computed tomography (CT)-guided biopsy in the management of Potts disease since the technique is becoming increasingly available.

Overview of Literature

CT-guided biopsy of spinal lesions is routinely performed. Literature on the utility of the technique in endemic resource poor countries is little.

Methods

This study was conducted at the Neurosurgery section of Aga Khan University Hospital Karachi. All the patients with suspected Potts disease who underwent CT-guided biopsy during the 7 year period from 2007 to 2013 were included in this study. Details of the procedure, histopathology and microbiology were recorded.

Results

One hundred and seventy-eight patients were treated for suspected Potts disease during the study period. CT-guided biopsies of the spinal lesions were performed in 91 patients (51.12%). Of the 91 procedures, 22 (24.2%) were inconclusive because of inadequate sample (10), normal tissue (6) or reactive tissue (6). Sixty-nine biopsies were positive (75.8%). Granulomatous inflammation was seen in 58 patients (84.05%), positive acid-fast bacillus (AFB) smear in 4 (5.7%) and positive AFB culture in 12 patients (17.3%). All 91 cases in which CT-guided biopsy was performed responded positively to antituberculosis therapy (ATT).

Conclusions

75.8% of the specimens yielded positive diagnoses. Granulomatous inflammation on histopathology was the commonest diagnostic feature. In this series, the rates of positive AFB smear and culture were low compared to previous literature.

Cervical chondrosarcoma- rare malignancy: a case report

To highlight an uncommon bone malignancy, which presented to our institute, as a neck swelling in the supraclavicular region. A 30 year old man presented with history of swelling on the left side of neck since 1 year and numbness of left upper limb since 6 months. Magnetic Resonance Imaging of the Cervical spine & MR Angiography showed a 7.4 × 4.6 cm expansile lesion involving transverse process of C5-C7 vertebrae. As the tumour was found to be deep to the phrenic nerve & brachial plexus, a dual approach was used, anteriorly via neck incision and posteriorly via the spine. The tumour was resected & iliac crest grafted along with stabilization of the cervical spine. Patient is disease free and the cervical spine stabilized with normal movements at two and half years follow up. We need to consider tumour arising from the vertebra as a differential diagnosis for any deep seated hard neck swelling in the supraclavicular region. Even low grade malignancy of this region when resected en-bloc will have a good prognosis.

Resultados de biopsia guiada por tomografía axial computarizada en el síndrome de destrucción vertebral, evaluados en dos instituciones distintas

OBJETIVO: Comparar resultados de biopsias vertebrales guiadas por tomografía axial computarizada, reportados por dos servicios de Anatomía Patológica distintos en pacientes con síndrome de destrucción vertebral para confirmar confiabilidad y utilidad en el diagnóstico. MÉTODOS: Se obtuvieron muestras de tejido de 21 pacientes en el periodo comprendido del 1 de marzo al 15 de julio del 2011 con el diagnóstico del síndrome de destrucción vertebral y a quienes se les realizó biopsia guiada por tomografía axial computarizada. Las muestras se enviaron en forma cegada a dos servicios de patología distintos. Los resultados fueron analizados con el método de comparación de dos proporciones. RESULTADOS: 14 pacientes fueron del género masculino (67%) y 7 del femenino (23%), edades de 28-82, con afección principalmente lumbar (48%) y torácica (38%); afectados en una vértebra en 62%, en dos en un 33% y en 3 o más niveles en 5%. Las vértebras más afectadas fueron L1, L2 y L3 (12/30 [40%]), T4 (3/30 [10%]) y T9 (3/30 [10%]). Los resultados se agruparon en categorías: 1. Osteomielitis (9/21 [43%]), 2. Tumores (7/21 [33%]), 3. Metástasis (3/21 [14%]), 4. Tejido normal (2/21 [10%]), 5. Inflamación (0/21 [0%]), 6. Muestra inadecuada (0/21 [0%]), 7. Mal de Pott (0/21 [0%]). CONCLUSIONES: De acuerdo a los valores de Z obtenidos mediante la prueba de comparación de dos proporciones no se encontró diferencia significativa entre los resultados reportados por dos los dos servicios de patología en el síndrome estudiado, determinándose que esta parte del proceso es confiable y útil en un 90%.

Efficacy of CT-guided biopsies of the spine in patients with spondylitis--an analysis of 164 procedures

OBJECTIVE

To evaluate efficacy of CT-guided spinal biopsy (CTSB) in patients with spondylitis considering patient characteristics, technical issues, antibiotic therapy, histopathological, and microbiological findings.

MATERIALS AND METHODS

All CTSB procedures performed between 1995 and 2009 in patients with proven spondylitis were re-evaluated. Patient sex and age, antibiotic treatment, biopsy approach, number of specimens, length of needle path, laboratory results (CRP, WBC), and histopathological/microbiological findings were documented and compared to the final diagnosis of spondylitis. Statistical analysis was performed using Chi-square test and Student's t-test. The p-value was set to 5%.

RESULTS

164 CTSB procedures were performed in 159 patients (mean age 65 years, 60% men) in which spondylitis was histopathologically verified in 95%. Neither patient sex nor age, positioning, localization of the spinal lesion, bioptic approach, number of specimens, or depth of the needle showed significant impact on the rate of positive histopathological findings. A causative germ was identified in 40/127 biopsies (32%) with Staphylococcus aureus being identified in 50%. Tuberculous spondylitis was diagnosed in ten cases (6%). CRP significantly correlated with bacterial growth (13.3±12.2 mg/dl versus 8.8±7.6 mg/dl; p=.015) whereas administration of antibiotics did not show any significant impact on bacterial growth (29% versus 36% in patients without antibiotics; p=0.428). Patients with histopathological signs of active spondylitis showed a significantly higher CRP (16.5±15.8 mg/dl versus 8.9±8.0 mg/dl, p<.001). Complication rate was 0.6% (one focal bleeding).

CONCLUSION

CTSB of the spine in suspected spondylitis is an effective and safe procedure for establishing final histopathological diagnosis. However, microbiological yield is low regardless of technical issues and antibiotic therapy. Other than CRP values, laboratory investigations added little useful information to diagnose infection in our study group. CRP values significantly correlated with bacterial growth and with histopathological signs of active spondylitis.

CT-guided needle biopsy for musculoskeletal lesions

INTRODUCTION

We determined the diagnostic accuracy rate of 207 cases that underwent CT-guided needle biopsy for musculoskeletal lesions during the past 10 years, and describe the efficacy and indications of this method.

MATERIALS AND METHODS

We retrospectively analyzed a consecutive series of 207 cases that presented to our oncology group and underwent CT-guided needle biopsy during the 10-year period between April 1998 and March 2008. Diagnostic accuracy was assessed statistically by anatomical location and final diagnosis. The biopsy site was the spine/sacrum in 70 cases, pelvis in 53, extremities in 51, rib/scapula in 20, and retroperitoneum in 13. Bone lesions were detected in 176 cases and soft tissue lesions in 31. The final diagnosis was metastatic tumor in 63 cases, primary bone tumor in 63, primary soft tissue tumor in 23, infection in 18, and hematopoietic malignancy in 16 and non-tumorous lesions in 24.

RESULTS

The diagnostic accuracy rate for all cases was 90%. No serious complications were seen. No statistically significant difference was found by anatomical site. According to the final diagnosis, benign tumors/malignant tumors (p < 0.005), primary bone tumor (p < 0.01), and infectious conditions (p < 0.001) showed significantly low diagnostic accuracy rates.

DISCUSSION

CT-guided needle biopsy is a safe method with high diagnostic accuracy for musculoskeletal lesions. However, in patients with a primary bone tumor, it should be indicated for the initial diagnosis. If a comprehensive assessment based on the imaging conflicts with the pathological findings, an open biopsy should be considered.

Percutaneous intervention of the C2 vertebral body using a CT-guided posterolateral approach

OBJECTIVE

The objective of this article is to present two cases of percutaneous biopsy and one case of vertebroplasty of the C2 vertebral body using a CT-guided posterolateral approach under local anesthesia.

CONCLUSION

The CT-guided posterolateral approach was safe, feasible, and effective for percutaneous intervention of the C2 vertebral body.

Approaches for percutaneous needle placement for various head and neck procedures

Use of image-guidance allows safe and precise percutaneous placement of needles for various diagnostic and therapeutic procedures in the head and neck region. This review describes the anatomy relevant to safe-access route planning and the techniques, advantages, and limitations associated with various approaches used for percutaneous needle placement in different head and neck regions. Subzygomatic, retromandibular, paramaxillary, submastoid, transoral, and posterior approaches can be used for percutaneous access in the suprahyoid head and neck region, including skull base and upper cervical vertebrae. In the infrahyoid portion of the neck and for lower cervical vertebrae, access can be achieved via the anterolateral (between the airways and the carotid sheath), posterolateral (posterior to the carotid sheath), and direct posterior approaches.

Image-guided musculoskeletal biopsy

Image guidance allows safe passage of needles, often into small and otherwise inaccessible lesions, and into the portions of the lesion most likely to yield useful samples, while avoiding damage to important structures. This article hopes to provide a useful guide to image-guided musculoskeletal biopsy for radiologists in practice and in training.

Effectiveness of CT-guided percutaneous biopsies of the spine: an analysis of 202 examinations

RATIONALE AND OBJECTIVES

The study goal was to retrospectively evaluate the effectiveness of computed tomography (CT)-guided spinal biopsies.

MATERIAL AND METHODS

Two hundred two CT-guided vertebral biopsies performed between May 1999 and June 2004 in 187 patients were retrospectively analyzed. Patient characteristics (age, sex, antibiotic therapy), technical parameters (depth and number of biopsies, needle approach), lesion features (spinal level, osteolysis, fluid collections, soft tissue tumor), and complications were documented. Furthermore, histopathological and microbiological diagnoses were considered.

RESULTS

There were two focal hematomas in our study group (complication rate: 1%). Histopathological diagnosis was established in 74% of examinations with spondylitis (41% of cases) being most common. In spinal tumors (27% of cases), malignant lesions were found in 52 of 54 examinations (96%). Osteolysis was diagnosed in 98% of patients with spondylitis and in 87% of patients with tumors (P < .01). Spinal tumors were most commonly seen in the sacrum (53%, P < .001), whereas spondylitis typically occurred in the lumbar spine (55%, P = .001). Neither patient age nor sex, needle approach, needle depth, or vertebral abnormalities showed a significant impact on diagnostic accuracy. Microbiological tests were performed in 98 patients (49%); 62 of 98 patients (65%) received antibiotic therapy. In 12 of 62 patients (19%) with antibiotic therapy and in 9 of 36 patients (25%) without antibiotic treatment, microbiological tests were positive (P = .153). Staphylococcus aureus was found in 9 of 21 examinations (43%).

CONCLUSIONS

CT-guided vertebral biopsy is a safe and effective procedure to establish final diagnosis in spinal lesions of unclear origin. Patient characteristics, lesions features, and technical considerations did not influence sample quality. In spondylitis, which was commonly caused by Staphylococcus aureus, microbiological yield was low regardless of antibiotic therapy.

Musculoskeletal biopsies using computed tomography fluoroscopy

OBJECTIVE

To determine the diagnostic yield, accuracy, and safety of computed tomography (CT) fluoroscopy guidance for musculoskeletal biopsies.

MATERIALS AND METHODS

A retrospective analysis of musculoskeletal biopsies performed with CT fluoroscopy guidance over a 2-year period was made. Data collected were biopsy sites, CT fluoroscopic times, and biopsy results. Results were categorized as the following: positive, negative (but diagnostic), or nondiagnostic. Reference standard consisted of 5 years of follow-up to verify results.

RESULTS

Ninety-five CT fluoroscopy-guided musculoskeletal biopsies were performed. Bone biopsies comprised 83% (79/95), and soft tissue biopsies comprised 17% (16/95). The mean age was 54 years (range, 16-90 years); 40.0% (38/95) were male subjects, and 60.0% (57/95) were female subjects. For all subjects, CT fluoroscopic times ranged from 2 to 310 seconds, with a mean time of 63 seconds and a median time of 34 seconds. The diagnostic yield was 96% (91/95), with a nondiagnostic result in 4% (4/95) of subjects. Diagnostic biopsy specimens showed a positive result in 63% (60/95) of subjects and a negative but diagnostic result in 33% (31/95) of subjects. There were no major complications.

CONCLUSIONS

Computed tomography fluoroscopic-guided musculoskeletal biopsies show a high diagnostic yield and are accurate and safe. The biopsy results are similar or superior to other published reports using conventional CT guidance with only a small overall fraction being nondiagnostic. The benefits of real-time imaging are at the cost of operator exposure to ionizing radiation and the risk of potentially high exposures to both patient and operator. The impact on indications for which lesions are most amenable to percutaneous biopsy using CT fluoroscopy and procedure time has yet to be determined.

Percutaneous Biopsy of Head and Neck Lesions with CT Guidance: Various Approaches and Relevant Anatomic and Technical Considerations

Deep-seated head and neck lesions, which traditionally were evaluated by surgical means, are now accessible with less invasive computed tomography-guided percutaneous needle biopsy techniques. Major vessels, the trachea, and osseous structures like the maxilla, mandible, and vertebrae often preclude direct access to these lesions. It is important to understand the anatomy relevant to safe access route planning and the techniques, advantages, and limitations associated with various approaches used for percutaneous biopsy of head and neck lesions. For biopsy of suprahyoid head and neck lesions, including those of the skull base and upper cervical vertebrae, various approaches such as the subzygomatic, retromandibular, paramaxillary, submastoid, transoral, and posterior approaches can be used. Lesions in the infrahyoid portion of the neck and lower cervical vertebrae can be accessed with the anterolateral approach (between the airways and the carotid sheath), posterolateral approach (posterior to the carotid sheath), and direct posterior approach. The location and extent of the lesions and their relationship to adjacent structures influence the choice of the trajectory to use. Careful planning of the procedure and considerable familiarity with head and neck anatomy are necessary for a biopsy that is both precise and safe.

Radiofrequency ablation of a cervical osteoid osteoma: a trans-thyroid approach

We present a 16-year-old girl with an osteoid osteoma in the vertebral body of C5. Given the difficulty of surgically treating the lesion, radiofrequency ablation was used. Percutaneous needle access to this lesion in the anterior aspect of the cervical vertebral body was limited by the many critical adjacent structures. We present our successful treatment of this lesion utilizing a trans-thyroid needle approach.

CT-guided core biopsy of subchondral bone and intervertebral space in suspected spondylodiskitis

OBJECTIVE

Our objective was to determine the diagnostic performance of CT-guided core biopsy including both intervertebral disks and subchondral bone in suspected spondylodiskitis and compare the results with those for other biopsy techniques.

CONCLUSION

CT-guided core biopsy of subchondral bone and intervertebral space compares favorably to previously published studies because histology can provide the diagnosis even when no specific infectious agent is isolated.

Application and utility of computed tomography-guided needle biopsy with musculoskeletal lesions

A retrospective study was performed on 73 patients who underwent percutaneous computed tomography-guided needle biopsy between April 1998 and March 2003. All cases were treated by orthopedic surgeons at Nagoya Memorial Hospital. Diagnostic accuracy was examined statistically by anatomical location and diagnosis. The diagnostic accuracy for all 73 patients was 88% (64/73); and excluding patients with infection, it was 92% (55/60). No statistically significant difference was found by anatomical site. The accuracy was statistically significantly lower for primary bone tumors (P<0.005) and infection (P<0.05). The culture detection rate was 23% (3/13). No serious complications were seen. This report suggests that, with the advances in imaging technology and biopsy needles, one no longer sees the differences in diagnostic accuracy by anatomical site that result from the use of different biopsy needles for tumors of different locations and properties. Accuracy is thus determined largely by the disease. Infection was tuberculous in 4 of the 13 infection patients, and diagnosis was possible in all of these cases from the tissue examination. Needle biopsy seems useful in the sense that it can distinguish between tuberculous lesions in cases of spinal infection. In patients with a primary bone tumor, application of needle biopsy should be subjected to further consideration.

Technology improvements for image-guided and minimally invasive spine procedures

This paper reports on technology developments aimed at improving the state of the art for image-guided minimally invasive spine procedures. Back pain is a major health problem with serious economic consequences. Minimally invasive procedures to treat back pain are rapidly growing in popularity due to improvements in technique and the substantially reduced trauma to the patient versus open spinal surgery. Image guidance is an enabling technology for minimally invasive procedures, but technical problems remain that may limit the wider applicability of these techniques. The paper begins with a discussion of low back pain and the potential shortcomings of open back surgery. The advantages of minimally invasive procedures are enumerated, followed by a list of technical problems that must be overcome to enable the more widespread dissemination of these techniques. The technical problems include improved intraoperative imaging, fusion of images from multiple modalities, the visualization of oblique paths, percutaneous spine tracking, mechanical instrument guidance, and software architectures for technology integration. Technical developments to address some of these problems are discussed next. The discussion includes intraoperative computerized tomography (CT) imaging, magnetic resonance imaging (MRI)/CT image registration, three-dimensional (3-D) visualization, optical localization, and robotics for percutaneous instrument placement. Finally, the paper concludes by presenting several representative clinical applications: biopsy, vertebroplasty, nerve and facet blocks, and shunt placement. The program presented here is a first step to developing the physician-assist systems of the future, which will incorporate visualization, tracking, and robotics to enable the precision placement and manipulation of instruments with minimal trauma to the patient.

Diagnostic value of open and needle biopsies in tumors of the sacrum

STUDY DESIGN

A retrospective study with statistical analysis of 25 percutaneous needle biopsies and 54 open biopsies performed on 60 patients with tumors located in the sacrococcygeal region.

OBJECTIVES

To analyze the diagnostic value of open and needle biopsies in tumors of the sacrum as well as to determine factors leading to a false or equivocal result.

SUMMARY OF BACKGROUND DATA

Although percutaneous needle biopsies of the spine are valuable for thoracolumbar levels, the benefit in the sacrococcygeal region, specifically, has not previously been shown. This region is unique because of anatomic and oncologic factors.

METHODS

Medical charts, imaging studies, and operative and pathologic records of patients with tumors diagnosed between 1965 and 1996 in the sacrococcygeal region reviewed were analyzed. Accuracy and effective accuracy of each procedure were then calculated.

RESULTS

There were 54 primary lesions (17 benign, 37 malignant) and 6 metastatic tumors. The accuracy and effective accuracy of open biopsies was 87% and 81% but in percutaneous needle biopsies was only 44% and 12%, respectively. An unclear diagnosis resulted in the need for another biopsy in 12 of 21 primary percutaneous needle biopsies but only in 2 of 39 open biopsies (P < 0.0001, chi2). The average number of biopsies required to obtain a definitive diagnosis was significantly less if an open biopsy were performed first instead of a percutaneous needle biopsy, 1.1 versus 1.8, respectively (P = 0.0004, two-sample t test). There was a significant delay in treatment if the initial biopsy was a percutaneous needle biopsy compared with an open biopsy, mean 46 versus 4 days, respectively (P = 0.004, two-sample t test).

CONCLUSION

We conclude that for sacral tumors, open biopsies have a higher effective accuracy, whereas needle biopsies are associated with a longer delay in treatment.

Automatic lumbar vertebral identification using surface-based registration

This work proposes the use of surface-based registration to automatically select a particular vertebra of interest during surgery. Manual selection of the correct vertebra can be a challenging task, especially for closed-back, minimally invasive procedures. Our method uses shape variations that exist among lumbar vertebrae to automatically determine the portion of the spinal column surface that correctly matches a set of physical vertebral points. In our experiments, we register vertebral points representing posterior elements of a single vertebra in physical space to spinal column surfaces extracted from computed tomography images of multiple vertebrae. After registering the set of physical points to each vertebral surface that is a potential match, we then compute the standard deviation of the surface error for each registration trial. The registration that corresponds to the lowest standard deviation designates the correct match. We have performed our current experiments on two plastic spine phantoms and two patients.

Sonographically guided fine-needle aspiration biopsy of lytic lesions of the spine: technique and indications

PURPOSE

We report the use of sonography to guide fine-needle aspiration biopsies (FNABs) of lytic lesions of the spine.

METHODS

Twenty-nine patients with lytic vertebral lesions with or without associated extraosseous soft-tissue extension underwent sonographically guided FNAB. Twelve cervical, 7 thoracic, 7 lumbar, and 3 sacral lesions were biopsied. Tissue samples were taken from either the bony lesion through a break in the cortex (n = 9) or the associated soft-tissue extension (n = 20).

RESULTS

Adequate diagnostic material obtained in 27 cases (93%) revealed an inflammatory (n = 13) or malignant process (n = 14). Of the 2 patients with inconclusive FNAB findings, 1 patient was lost to follow-up, and the other underwent surgery, which revealed tuberculosis. No complications of FNAB were encountered.

CONCLUSIONS

We conclude that sonography is a safe and effective guidance modality for FNAB of lytic lesions of the spine, especially for lesions in the cervical region. In the thoracic, lumbar, and sacral regions, however, the role of sonographically guided FNAB is limited to lesions affecting the posterior elements.

Lytic bone lesions suspected for metastasis: ultrasonically guided fine-needle aspiration biopsy

Ultrasonically guided fine-needle aspiration biopsy (US-FNAB) was performed in 30 patients with a lytic bone lesions suspected for metastasis detected by conventional radiological examinations. The patients were selected for US-FNAB on the basis of the ability of the ultrasound examination to clearly visualize the lesion. The cytological diagnosis was confirmed at surgery in 3 cases, and at clinical and radiological follow-up after more than 6 months in the remaining cases. The lesions were located mostly in the thoracic skeleton (ribs and sternum) and pelvic bone. We diagnosed malignancy in 26 cases and benign lesions in 2 cases. An inadequate sample was obtained in 1 case, and 1 case yielded a false-negative result. According to these results, we obtained a sensitivity of 93%. We conclude that ultrasonically guided fine-needle aspiration biopsy is a useful technique to obtain a pathological diagnosis in cases of lytic bone lesions that can be visualized with this imaging technique.

CT-guided percutaneous biopsy of the cervical spine: a series of 12 cases

Twelve patients underwent biopsy of cervical vertebral bodies under CT guidance. An accurate diagnosis was obtained in 11. No complications were observed, except for a transitory recurrent laryngeal nerve palsy. Technical problems of the cervical spine biopsy are discussed and the utility of bone biopsy with a coaxial trephine system is emphasized.

Percutaneous skeletal biopsy

Percutaneous bone biopsy has become an accepted means for tissue diagnosis in indeterminate metastatic disease, whereas needle biopsy for the evaluation of primary skeletal neoplasms is controversial. Needle biopsies are also of value in the diagnosis of inflammatory lesions and eosinophilic granuloma. The diagnostic accuracy of this procedure ranges from 50 to 94% in malignant disease, but is less favorable in benign disease. The low complication rate of about 0.2% makes the percutaneous approach an attractive alternative to surgical biopsy.