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Biomedical subjects

William C Welch

Publications and source records attributed to William C Welch.

At least 19 recordsLinked to original sources
PubMed2007

Radiosurgery for spinal metastases: clinical experience in 500 cases from a single institution.

STUDY DESIGN: A prospective nonrandomized, longitudinal cohort study. OBJECTIVE: To evaluate the clinical outcomes of single-fraction radiosurgery as part of the management of metastatic spine tumors. SUMMARY OF BACKGROUND DATA: The role of stereotactic radiosurgery for the treatment of spinal lesions has previously been limited by the availability of effective target immobilization and target tracking devices. Large clinical experience with spinal radiosurgery to properly assess clinical experience has previously been limited. METHODS: A cohort of 500 cases of spinal metastases underwent radiosurgery. Ages ranged from 18 to 85 years (mean 56). Lesion location included 73 cervical, 212 thoracic, 112 lumbar, and 103 sacral. RESULTS: The maximum intratumoral dose ranged from 12.5 to 25 Gy (mean 20). Tumor volume ranged from 0.20 to 264 mL (mean 46). Long-term pain improvement occurred in 290 of 336 cases (86%). Long-term tumor control was demonstrated in 90% of lesions treated with radiosurgery as a primary treatment modality and in 88% of lesions treated for radiographic tumor progression. Twenty-seven of 32 cases (84%) with a progressive neurologic deficit before treatment experienced at least some clinical improvement. CONCLUSIONS: The results indicate the potential of radiosurgery in the treatment of patients with spinal metastases, especially those with solitary sites of spine involvement, to improve long-term palliation.

Adult↗
PubMed2007

Combined percutaneous transpedicular tumor debulking and kyphoplasty for pathological compression fractures. Technical note.

Percutaneous balloon kyphoplasty has become a widely adopted treatment option for patients with pain due to pathological compression fractures. One potential risk of the procedure is the displacement of tumor into the spinal canal and resulting spinal cord or cauda equina injury during inflation of the balloon prior to polymethylmethacrylate (PMMA) placement. In addition, the presence of any remaining tumor between the PMMA and the fractured cortical bone can lead to suboptimal improvement in stabilization and subsequent pain relief. The authors describe a technique to remove tumor from within the vertebral body (VB) through a percutaneous working channel prior to kyphoplasty balloon inflation and augmentation. The technique was successfully used in all three patients who had presented with pain, and the pain improved in all three cases. There was no extravasation of PMMA into the spinal canal in any case. A combined VB tumor debulking and kyphoplasty technique offers the ability to improve the placement of PMMA within the diseased vertebral body, potentially leading to increased safety as well as clinical effectiveness for stabilization of these fractures.

Adult↗
PubMed2006

Radiosurgery for the treatment of spinal lung metastases.

BACKGROUND: Spinal metastases are a common source of pain as well as neurologic deficit in patients with lung cancer. Metastases from lung cancer traditionally have been believed to be relatively responsive to radiation therapy. However, conventional external beam radiotherapy lacks the precision to allow delivery of large single-fraction doses of radiation and simultaneously limit the dose to radiosensitive structures such as the spinal cord. The current study evaluated the efficacy of single-fraction radiosurgery for the treatment of spinal lung cancer metastases. METHODS: In the current prospective cohort evaluation, 87 lung cancer metastases to the spine in 77 patients were treated with a single-fraction radiosurgery technique with a follow-up period of 6 to 40 months (median, 12 months). The indication for radiosurgery treatment was pain in 73 cases, as a primary treatment modality in 7 cases, for radiographic tumor progression in 4 cases, and for progressive neurologic deficit in 3 cases. RESULTS: Tumor volume ranged from 0.2 to 264 cm(3) (mean, 25.7 cm(3)). The maximum tumor dose was maintained at 15 to 25 grays (Gy) (mean, 20 Gy; median, 20 Gy). No radiation-induced toxicity occurred during the follow-up period. Long-term axial and radicular pain improvement occurred in 65 of 73 patients (89%) who were treated primarily for pain. Long-term radiographic tumor control was observed in all patients who underwent radiosurgery as their primary treatment modality or for radiographic tumor progression. CONCLUSIONS: Spinal radiosurgery was found to be feasible, safe, and clinically effective for the treatment of spinal metastases from lung cancer. The results of the current study indicate the potential of radiosurgery in the treatment of patients with spinal lung metastases, especially those with solitary sites of spine involvement, to improve long-term palliation.

Adult↗
PubMed2006

Intraoperative somatosensory evoked potential monitoring during anterior cervical discectomy and fusion in nonmyelopathic patients--a review of 1,039 cases.

BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals.

Adult↗
PubMed2006

High rate of fusion in sheep cervical spines following anterior interbody surgery with absorbable and nonabsorbable implant devices.

STUDY DESIGN: Fourteen sheep were fused using anterior interbody implants at C2-C3 and C4-C5 and followed for 6 months. OBJECTIVE: To evaluate the effect of absorbable and nonabsorbable implants on fusion rate, cage migration, and implant integrity. SUMMARY OF BACKGROUND DATA: Despite the high clinical success rate with metallic plates and interbody grafting, complications such as dysphagia, imaging artifacts, and revision difficulties exist. Less permanent and lower profile implants could minimize these problems. METHODS: Four treatments were studied: 1) carbon fiber-reinforced polymer (CFRP) cage alone, 2) CFRP cage with an absorbable tension band, 3) absorbable cage with an absorbable tension band, and 4) absorbable cage with a titanium plate. Fusion was assessed using radiographs, biomechanical testing, and micro-CT analysis. RESULTS: Treatments with the CFRP cage alone had the lowest fusion rate at 3 months (2/6) and 6 months (4/6). The CFRP cage with the absorbable strap treatments had 5/6 fusions at 6 months. The absorbable cage with absorbable strap also had 5/6 fusions, but two of the cages fractured. The absorbable cage with titanium plate had 5/6 fusions, but the one partial fusion was attributed to poor screw and plate placement. CONCLUSION: Using both absorbable and nonabsorbable implants, high fusion rates were achieved in the challenging sheep cervical spine model. However, the absorbable cages were not able to withstand the mechanical forces during the 6-month survival period.

Absorbable Implants↗
PubMed2006

Intraoperative somatosensory evoked potential monitoring during cervical spine corpectomy surgery: experience with 508 cases.

STUDY DESIGN: Retrospective review. OBJECTIVES: To review consecutive cases of cervical spine corpectomy surgery performed with intraoperative somatosensory-evoked potential (SSEP) monitoring. SUMMARY OF BACKGROUND DATA: There is controversy about the utility of SSEP monitoring during anterior cervical spine surgery. There is no study in the literature that has specifically evaluated the utility of SSEP monitoring for cervical spine corpectomy surgery. METHODS: Intraoperative SSEP tracings for 508 patients (average age, 55.7 years; 268 male, 240 female) who underwent anterior cervical fusion with single-level or multilevel corpectomies were reviewed. Intraoperative and postoperative records were analyzed to determine if any new neurologic deficits developed when the patients woke up from anesthesia. RESULTS: The overall incidence of a new postoperative neurologic deficit in this series of patients was 2.4% (11 with nerve root injury, 1 with quadriplegia). The incidence of significant SSEP changes was 5.3% (27 of 508 patients). The most common identifiable cause of SSEP changes was hypotension, and the most common neurologic deficit was deltoid (C5) weakness. One patient had irreversible SSEP changes, and he woke up with new-onset quadriplegia. The calculated sensitivity and specificity of intraoperative SSEP monitoring for detecting impending or resultant intraoperative iatrogenic neurologic injury were 77.1% and 100%, respectively. However, if the isolated nerve root injuries are removed from the analysis, then both the calculated sensitivity and the negative predictive values were 100%. CONCLUSIONS: Intraoperative SSEP monitoring can alert the surgeon to adverse iatrogenic intraoperative events with potential for neurologic injury. Most SSEP signal changes are reversible and do not result in a clinical deficit. Isolated nerve root injury appears to be the most common iatrogenic intraoperative injury during cervical spine corpectomy surgery.

Adult↗
PubMed2006

Spine: minimally invasive techniques.

Minimally invasive spine surgery decompression, arthrodesis, and instrumentation techniques are now being applied in a wide variety of percutaneous, laparoscopic and minimal access procedures. There is currently little longitudinal long-term data on these procedures to document their efficacy, indications, limitations or complications as compared to standard open techniques. Further complicating such direct comparisons is that widely used spine outcomes instruments often do not capture the relative benefits of these new procedures. It is only through randomized trials that the potential benefits of these procedures be substantiated in order to justify the sometimes significant increased costs associated with them.

Cost-Benefit Analysis↗
PubMed2006

Quality of life assessment in patients undergoing nucleoplasty-based percutaneous discectomy.

OBJECT: Nucleoplasty is a minimally invasive surgical procedure for disc decompression developed to treat patients with symptomatic contained herniated discs. Nucleoplasty uses nonheat-driven radiofrequency energy to ablate and coagulate the disc nucleus via a percutaneous "discography" trajectory under fluoroscopic guidance. In this study the authors evaluated pain, functioning, and quality of life (QOL) in patients with radicular leg and back pain who underwent nucleoplasty-based percutaneous disc decompression. METHODS: The study was designed as a prospective nonrandomized longitudinal cohort study in an academic medical center. Sixty-seven patients (mean age 41 years) with primarily radicular pain due to a contained disc herniation underwent nucleoplasty-based decompression in an outpatient setting. Patients completed the Medical Outcomes Study 36-Item Short Form (SF-36) Health Survey, EuroQol 5D (EQ5D), and a visual analog scale (VAS) for pain preoperatively, and at 3 and 6 months after surgery. Postoperative QOL differences were assessed using the Wilcoxon signed-rank test. A surgical probe, the Perc-DLE SpineWand, was placed percutaneously into the disc after application of a local anesthetic or induction of general anesthesia to remove part of the disc (that is, a percutaneous discectomy). Nucleoplasty-treated levels were L2-3 (one case), L3-4 (five cases), L4-5 (44 cases), and L5-S 1 (40 cases); there were 22 multiple treatment levels and 42 bilateral treatments. There were no infections or nerve root injuries associated with the procedure. Compared with preoperative QOL, there was a statistically significant improvement in QOL at 3 months as measured using the SF-36 Physical Component Summary (PCS) scale (mean score improvement 4.4 [p = 0.014]), the EQ5D (mean score improvement 0.22 [p = 0.001]), and the VAS for pain (mean score improvement 0.13 [p = 0.021). Six-month results in 36 patients continued to reflect improvement as measured using the SF-36 PCS (mean score improvement 7.6 [p = 0.002]) and the EQ5D (mean score improvement 0.27 [p = 0.001]). CONCLUSIONS: Nucleoplasty-based percutaneous disc decompression in patients with symptomatic contained disc herniations is safe and improves QOL as measured by the SF-36, EQ5D, and VAS for pain, three generic QOL outcome instruments. Nucleoplasty is an effective minimally invasive surgical treatment alternative in patients with symptomatic contained disc hemiations. Further follow-up evaluation is underway to determine the durability of QOL improvement after nucleoplasty.

Adult↗
PubMed2005

Single-fraction radiosurgery for the treatment of spinal breast metastases.

BACKGROUND: The spine is the most common site of bony metastases in patients with osseous breast carcinoma metastases. Spine metastases are the source of significant pain and occasionally neurologic deficit in this patient population. Conventional external beam radiotherapy lacks the precision to allow delivery of large single-fraction doses of radiation and simultaneously limit the dose to radiosensitive structures such as the spinal cord. This study evaluated the clinical efficacy of the treatment of spinal breast carcinoma metastases with a single-fraction radiosurgical technique. METHODS: In this prospective cohort evaluation, 68 breast carcinoma metastases to the spine in 50 patients were treated with a single-fraction radiosurgery technique with a follow-up period of 6-48 months, median 16 months. The most common indication for radiosurgery treatment was pain in 57 lesions, as a primary treatment modality in 8 patients, and for radiographic tumor progression, as a postsurgical boost, and for a progressive neurologic deficit in 1 patient each. RESULTS: Tumor volume ranged from 0.8-197 cm3 (mean, 27.7 cm3). Maximum tumor dose was maintained at 15-22.5 Gy (mean, 19 Gy). No radiation-induced toxicity occurred during the follow-up period (6-48 mo). Long-term axial and radicular pain improvement occurred in 55 of 57 (96%) patients who were treated primarily for pain. Long-term radiographic tumor control was seen in all patients who underwent radiosurgery as their primary treatment modality, for radiographic tumor progression, or as a postsurgical treatment. CONCLUSIONS: Spinal radiosurgery was found to be feasible, safe, and clinically effective for the treatment of spinal metastases from breast carcinoma. The results indicate the potential of radiosurgery in the treatment of patients with spinal breast metastases, especially those with solitary sites of spine involvement, to improve long-term palliation.

Adult↗
PubMed2005

Combination kyphoplasty and spinal radiosurgery: a new treatment paradigm for pathological fractures.

OBJECT: Patients with symptomatic pathological compression fractures require a stabilization procedure for mechanical control of back pain as well as radiation therapy for the underlying malignant process. In this study the authors evaluated a treatment paradigm of closed fracture reduction and fixation in which kyphoplasty was used, followed by single-fraction spinal radiosurgery performed with the CyberKnife. METHODS: Twenty-six patients (six men and 20 women, mean age 72 years) with histologically confirmed pathological compression fractures (16 thoracic, 10 lumbar) were prospectively evaluated. For inclusion in the study, the patients' presenting symptoms were limited to pain without neurological deficits. Histological findings included 11 lung, nine breast, and four renal carcinomas, one cholangiocarcinoma, and one ocular melanoma. All patients underwent kyphoplasty of the affected vertebral body, for which a percutaneous transpedicular procedure was used. Fiducial markers that allow image guidance for CyberKnife radiosurgery were placed into the pedicles at the adjacent levels at the time of the kyphoplasty procedure. Patients then underwent single-fraction radiosurgery (at a mean of 12 days after kyphoplasty) in an outpatient setting. The tumor dose was maintained at 16 to 20 Gy to the 80% isodose line (mean 18 Gy). Treated tumor volume ranged from 12.7 to 37.1 cm3. Axial pain improved in 24 (92%) of 26 patients during the follow-up period of 7 to 20 months. CONCLUSIONS: A combined kyphoplasty and spinal radiosurgery treatment paradigm was found to be safe and clinically effective for patients with pathological fractures without significant spinal canal compromise. This technique combines two minimally invasive surgical procedures, thereby avoiding the morbidity associated with open surgery while providing immediate fracture fixation as well as a single-fraction tumoricidal radiation dose.

Aged↗
PubMed2005

Postoperative discitis due to Propionibacterium acnes: a case report and review of the literature.

BACKGROUND: No previous report has described a progressive, destructive postoperative discitis requiring operative stabilization due to Propionibacterium acnes. The clinical and radiographic features and treatment options associated with discitis due to P acnes are presented in a retrospective case study, as well as a review of the current literature. CASE DESCRIPTION: Seven weeks after a routine lumbar discectomy, the patient presented with clinical findings and radiographic imaging consistent with discitis. Intraoperative cultures obtained from irrigation and debridement of the disc space revealed P acnes, and appropriate intravenous antibiotic treatment was instituted. Approximately 2 months later, the patient showed progression to a destructive osteomyelitis requiring operative stabilization. Nine weeks after stabilization, the patient continued to have lower back pain without radiculopathy. Laboratory values had normalized. Radiographic imaging revealed good instrumentation positioning and adequate fusion. The patient was ambulatory with bilateral articulating ankle foot orthoses and a walker. CONCLUSION: The reported case adds to the literature on postoperative discitis due to P acnes and demonstrates that this organism can occasionally be the cause of progressive, destructive osteomyelitis. In addition, we review the incidence, risk factors, and clinical course of discitis due to P acnes.

Diskectomy↗
PubMed2005

CyberKnife Frameless Radiosurgery for the treatment of extracranial benign tumors.

Limited data exists for the use of radiosurgery for benign extracranial tumors. The purpose of this study was to evaluate the feasibility, toxicity, and local control of patients with benign extracranial lesions treated with the CyberKnife Frameless Radiosurgery System. From September 2001 thru January 2004, 59 benign tumors in 44 patients were treated using the CyberKnife a frameless image-guided radiosurgery system. Of these tumors, there were 21 neurofibromas, ten schwannomas, eight meningiomas, eight hemangioblastomas, seven paragangliomas, two hemangiopericytomas, one pseudotumor, one ependymoma, and one arteriovenous malformation (AVM). The anatomic locations of these tumors were spinal (25 cervical, four thoracic, 14 lumbar, and two sacral), neck (eight), orbital (three), brainstem (one), and foramen magnum (one). All patients were treated in a single fraction except three lesions were treated in a fractionated manner. The median treatment delivery time per fraction was 59 minutes (range 11-194). Twenty three lesions initially underwent surgical resection. Ten lesions received prior external beam radiation with a median dose 48 Gy (range 40-54 Gy), and one lesion received two prior CyberKnife treatments for a total dose of 32 Gy to the 80% isodose line. The median follow-up was eight months (range 1-25 months). Acute and late toxicity was graded using the National Cancer Institute Common Toxicity Criteria (CTC) scale. Symptomatic response was documented as "improved," "stable," or "progression". The median tumor dose delivered was 16.0 Gy to the 80% isodose line (range 10-31 Gy). The median tumor volume was 4.3 cc (range 0.14-98.6 cc). The median spinal cord volume receiving more than 8 Gy was 0.035 cc (range 0-2.5 cc) and the median maximum spinal cord dose 11.5 Gy (range 0-19.8 Gy). There were no patients that suffered a significant (Grade 3, 4, or 5) acute toxicity. There was no observed late toxicity. 78% of patients experienced an improvement of their pre-treatment symptoms while only one patient experienced symptom progression. Of the 26 patients who underwent follow-up imaging, the local control rate was 96%. This study suggests that CyberKnife Radiosurgery is a safe and efficacious treatment modality for benign tumors, even for those patients with recurrent previously irradiated lesions.

Brain Neoplasms↗
PubMed2005

Accuray CyberKnife image-guided radiosurgical system.

Radiosurgery is the application of radiation therapy in an extremely precise manner. These techniques apply large bioequivalent doses of radiation to a small area in order to destroy tumor cells, while sparing surrounding normal tissues. Radiosurgery has been available for intracranial abnormalities since the 1950s but it has only recently become available to treat tumors outside of the brain and skull base. This article outlines the authors experience with CyberKnife in the treatment of spinal and spine-associated abnormalities.

Clinical Trials as Topic↗
PubMed2005

Stereotactic radiosurgery for spinal metastases from renal cell carcinoma.

OBJECT: The role of stereotactic radiosurgery in treating renal cell carcinoma (RCC) metastases to the spine has previously been limited. In this study the authors evaluated the clinical outcome in patients with spinal RCC who underwent single-fraction radiosurgery. METHODS: Forty-eight patients with 60 RCC metastases to the spine (six cervical, 26 thoracic, 18 lumbar, and 10 sacral) were treated with a single-fraction radiosurgery technique and were followed for a period of 14 to 48 months (median 37 months). All patients were successfully treated in an outpatient setting. The tumor volume ranged from 5.5 to 203 cm3 (mean 61.9 cm3). Forty-two of the total 60 lesions had been previously treated with external-beam radiation therapy (EBRT). The maximum tumor dose was maintained at 17.5 to 25 Gy (mean 20 Gy). The volume of the spinal cord exposed to greater than 8 Gy ranged from 0.01 to 3 cm3 (mean 0.64 cm3); the volume of the spinal canal at the cauda equina level exposed to greater than 8 Gy ranged from 0.01 to 2.2 cm3 (mean 0.65 cm3). No radiation-induced toxicity occurred during the follow-up period. Axial and radicular pain improved in 34 (89%) of 38 patients who were treated primarily for pain. Tumor control was demonstrated in seven of eight patients treated primarily for radiographically documented tumor progression. In time six patients required open surgical intervention for tumor progression that had caused neurological dysfunction after radiosurgery. CONCLUSIONS: Spinal radiosurgery can be a successful therapeutic modality for the delivery of large-dose single-fraction radiation to RCC spinal metastases that are often poorly controlled with conventional EBRT modalities.

Aged↗
PubMed2005

Combination kyphoplasty and spinal radiosurgery: a new treatment paradigm for pathological fractures.

OBJECT: Patients with symptomatic pathological compression fractures require spinal stabilization surgery for mechanical back pain control and irradiation for the underlying malignant process. The authors evaluated a treatment paradigm of closed fracture reduction and fixation involving kyphoplasty and subsequent spinal radiosurgery. METHODS: Twenty-six patients (six men and 20 women, mean age 72 years) with pathological compression fractures (16 thoracic and 10 lumbar) were prospectively evaluated. Histological diagnoses included 11 lung, nine breast, four renal, one cholangiocarcioma, and one ocular melanoma. Seven lesions had received prior external-beam radiation therapy. All patients underwent kyphoplasty that involved the percutaneous transpedicular technique. Fiducial markers allowing for image guidance during CyberKnife treatment were placed, at time of the kyphoplasty, in the pedicles at adjacent levels. Patients underwent single-fraction radiosurgery (mean time after kyphoplasty 12 days) in an outpatient setting. The tumor dose was maintained at 16 to 20 Gy (mean 18 Gy) to the 80% isodose line. The treated tumor volume ranged from 12.7 to 37.1 cm3. No acute radiation-induced toxicity or new neurological deficit occurred during the follow-up period (range 11-24 months, median 16 months). Axial pain improved in 24 (92%) of 26 patients. CONCLUSIONS: The combined kyphoplasty and spinal radiosurgery treatment paradigm was found to be clinically effective in patients with pathological fractures; there was no significant spinal canal compromise. In this technique two minimally invasive surgical procedures are combined to avoid the morbidity associated with open surgery while providing both immediate fracture fixation and administering a single-fraction tumoricidal radiation dose.

Aged↗
PubMed2004

Use of polylactide resorbable film as a barrier to postoperative peridural adhesion in an ovine dorsal laminectomy model.

OBJECT: The purpose of this study was to evaluate the performance of a resorbable polylactide film in the sheep posterior spine in the presence of a combined laminectomy and durotomy defect. METHODS: A resorbable polylactide film was used to cover the combined defects in the eight sheep used in this study. Two surgical levels were performed in each animal, with randomly assigned control and treated sites. Each surgical level consisted of a full laminectomy followed by a needle-induced durotomy. The treated levels received a resorbable polylactide film cut to size and tucked in under the laminar defect. At 8 to 10 weeks postoperatively, results of myelography and visual dye infiltration showed complete healing of the durotomies for all sites. In addition, evaluation of gross dissection based on volume and tenacity scores as well as histological findings indicates decreased posterior dural adhesions for sites treated with resorbable polylactide film. CONCLUSIONS: The results of this investigation support previous studies in which the use of a resorbable polylactide film was found to be effective in reducing posterior dural adhesions in the spine with no apparent safety issues related to impaired dural healing.

Absorbable Implants↗