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Paul M. Arnold, Philip L. Johnson and Karen K. Anderson

Object

Symptomatic thoracic disc herniations (TDHs) are rare, and multiple TDHs account for an even smaller percentage of symptomatic herniated discs. Most TDHs are found in the lower thoracic spine, with more than 75% occurring below T-8. The authors report a series of 15 patients with multiple symptomatic TDHs treated with a modified transfacet approach.

Methods

Fifteen patients (9 women and 6 men) with a total of 32 symptomatic TDHs were treated surgically at the authors' institution between 1994 and 2010. The average patient age was 51.1 years. Thirteen patients had 2-level herniation and 2 patients had 3-level disease. The most commonly involved level was T7–8 (10 herniations), followed by T6–7 and T8–9 (6 herniations each). All patients had long-standing myelopathic and/or radicular complaints at the time of presentation. Each disc that exhibited radiographically confirmed compression of the spinal cord or nerve root was considered for resection. Only patients with lateral disc herniations were considered for the modified transfacet approach; patients with a centrally herniated disc underwent ventral or ventral-lateral procedures. The average follow-up time was 30 months.

Results

All patients had successful resection of their herniated discs. All patients with preoperative weakness demonstrated improved strength, and 11 of 12 patients with preoperative pain showed improvement in pain. Sensory loss was less consistently improved. The 2 patients who underwent posterior fixation and fusion achieved radiographically confirmed fusion by the 1-year follow-up. Nine of 10 patients who were working returned to their jobs. Eleven of 12 patients with preoperative back or radicular pain had drastic or complete pain resolution; 1 patient had no change in pain. All 7 patients with preoperative ambulatory difficulty had postoperative gait improvement. Complications were minimal.

Conclusions

Multiple symptomatic herniated thoracic discs are rare causes of pain and disability, but should be treated surgically because good outcomes can be achieved with acceptably low morbidity.

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Paul M. Arnold, Karen K. Anderson, Abdulhafez Selim, Randall F. Dryer and J. Kenneth Burkus

OBJECTIVE

Heterotopic ossification (HO) has been reported following total hip, knee, cervical, and lumbar arthroplasty, as well as following posterolateral lumbar fusion using recombinant human bone morphogenetic protein–2 (rhBMP-2). Data regarding HO following anterior cervical discectomy and fusion (ACDF) with rhBMP-2 are sparse. A subanalysis was done of the prospective, multicenter, investigational device exemption trial that compared rhBMP-2 on an absorbable collagen sponge (ACS) versus allograft in ACDF for patients with symptomatic single-level cervical degenerative disc disease.

METHODS

To assess differences in types of HO observed in the treatment groups and effects of HO on functional and efficacy outcomes, clinical outcomes from previous disc replacement studies were compared between patients who received rhBMP-2/ACS versus allograft. Rate, location, grade, and size of ossifications were assessed preoperatively and at 24 months, and correlated with clinical outcomes.

RESULTS

Heterotopic ossification was primarily anterior in both groups. Preoperatively in both groups, and including osteophytes in the target regions, HO rates were high at 40.9% and 36.9% for the rhBMP-2/ACS and allograft groups, respectively (p = 0.350). At 24 months, the rate of HO in the rhBMP-2/ACS group was higher than in the allograft group (78.6% vs 59.2%, respectively; p < 0.001). At 24 months, the rate of superior-anterior adjacent-level Park Grade 3 HO was 4.2% in both groups, whereas the rate of Park Grade 2 HO was 19.0% in the rhBMP-2/ACS group compared with 9.8% in the allograft group. At 24 months, the rate of inferior-anterior adjacent-level Park Grade 2/3 HO was 11.9% in the rhBMP-2/ACS group compared with 5.9% in the allograft group. At 24 months, HO rates at the target implant level were similar (p = 0.963). At 24 months, the mean length and anteroposterior diameter of HO were significantly greater in the rhBMP-2/ACS group compared with the allograft group (p = 0.033 and 0.012, respectively). Regarding clinical correlation, at 24 months in both groups, Park Grade 3 HO at superior adjacent-level disc spaces significantly reduced range of motion, more so in the rhBMP-2/ACS group. At 24 months, HO negatively affected Neck Disability Index scores (excluding neck/arm pain scores), neurological status, and overall success in patients in the rhBMP-2/ACS group, but not in patients in the allograft group.

CONCLUSIONS

Implantation of rhBMP-2/ACS at 1.5 mg/ml with polyetheretherketone spacer and titanium plate is effective in inducing fusion and improving pain and function in patients undergoing ACDF for symptomatic single-level cervical degenerative disc disease. At 24 months, the rate and dimensions (length and anteroposterior diameter) of HO were higher in the rhBMP-2/ACS group. At 24 months, range of motion was reduced, with Park Grade 3 HO in both treatment groups. The impact of Park Grades 2 and 3 HO on Neck Disability Index success, neurological status, and overall success was not consistent among the treatment groups. The study data may offer a deeper understanding of HO after ACDF and may pave the way for improved device designs.

Clinical trial registration no.: IDE# G060021; data compared with pooled data from control arms of IDE# G010188/NCT00642876 and IDE# G000123/NCT00437190 (www.clinicaltrials.gov).

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Douglas E. Anderson, John Leonetti, Joshua J. Wind, Denise Cribari and Karen Fahey

Object. Vestibular schwannoma surgery has evolved as new therapeutic options have emerged, patients' expectations have risen, and the psychological effect of facial nerve paralysis has been studied. For large vestibular schwannomas for which extirpation is the primary therapy, the goals remain complete tumor resection and maintenance of normal neurological function. Improved microsurgical techniques and intraoperative facial nerve monitoring have decreased the complication rate and increased the likelihood of normal to near-normal postoperative facial function. Nevertheless, the impairment most frequently reported by patients as an adverse effect of surgery continues to be facial nerve paralysis. In addition, patient assessment has provided a different, less optimistic view of outcome. The authors evaluated the extent of facial function, timing of facial nerve recovery, patients' perceptions of this recovery and function, and the prognostic value of intraoperative facial nerve monitoring following resection of large vestibular schwannomas; they then analyzed these results with respect to different surgical approaches.

Methods. The authors retrospectively reviewed a database of 67 patients with 71 vestibular schwannomas measuring 3 cm or larger in diameter. The patients had undergone surgery via translabyrinthine, retrosigmoid, or combined approaches. Clinical outcomes were analyzed with respect to intraoperative facial nerve activity, responses to intraoperative stimulation, and time course of recovery.

Eighty percent of patients obtained normal to near-normal facial function (House—Brackmann Grades I and II). Patients' perceptions of facial nerve function and recovery correlated well with the clinical observations.

Conclusions. Trends in the data lead the authors to suggest that a retrosigmoid exposure, alone or in combination with a translabyrinthine approach, offers the best chance of facial nerve preservation in patients with large vestibular schwannomas.

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Rajiv Sethi, Quinlan D. Buchlak, Vijay Yanamadala, Melissa L. Anderson, Eric A. Baldwin, Robert S. Mecklenburg, Jean-Christophe Leveque, Alicia M. Edwards, Mary Shea, Lisa Ross and Karen J. Wernli

OBJECTIVE

Systematic multidisciplinary approaches to improving quality and safety in complex surgical care have shown promise. Complication rates from complex spine surgery range from 10% to 90% for all surgeries, and the overall mortality rate is 1%–4%. These rates suggest the need for improved perioperative complex spine surgery processes designed to minimize risk and improve quality.

METHODS

The Group Health Research Institute and Virginia Mason Medical Center implemented a systematic multidisciplinary protocol, the Seattle Spine Team Protocol, in 2010. This protocol involves the following elements: 1) a comprehensive multidisciplinary conference including clinicians from neurosurgery, anesthesia, orthopedics, internal medicine, behavioral health, and nursing, collaboratively deciding on each patient's suitability for surgery; 2) a mandatory patient education course that reviews the risks of surgery, preparation for the surgery, and postoperative care; 3) a dual-attending-surgeon approach involving 1 neurosurgeon and 1 orthopedic spine surgeon; 4) a dedicated specialist complex spine anesthesia team; and 5) rigorous intraoperative monitoring of a patient's blood loss and coagulopathy. The authors identified 71 patients who underwent complex spine surgery involving fusion of 6 or more levels before implementation of the protocol (surgery between 2008 and 2010) and 69 patients who underwent complex spine surgery after the implementation of the protocol (2010 and 2012). All patient demographic variables, including age, sex, body mass index, smoking status, diagnosis of diabetes and/or osteoporosis, previous surgery, and the nature of the spinal deformity, were comprehensively assessed. Also comprehensively assessed were surgical variables, including operative time, number of levels fused, and length of stay. The authors assessed overall complication rates at 30 days and 1 year and detailed deaths, cardiovascular events, infections, instrumentation failures, and CSF leaks. Chi-square and Wilcoxon rank-sum tests were used to assess differences in patient characteristics for patients with a procedure in the preimplementation period from those in the postimplementation period under a Poisson distribution model.

RESULTS

Patients who underwent surgery after implementation of the Seattle Spine Team Protocol had a statistically significant reduction (relative risk 0.49 [95% CI 0.30–0.78]) in all measured complications, including cardiovascular events, wound infections, other perioperative infections, and implant failures within 30 days after surgery; the analysis was adjusted for age and Charlson comorbidity score. A trend toward fewer deaths in this group was also found.

CONCLUSIONS

This type of systematic quality improvement strategy can improve quality and patient safety and might be applicable to other complex surgical disciplines. Implementation of these strategies in the treatment of adult spinal deformity will likely lead to better patient outcomes.