Patent bibliometrics in spinal deformity: the first bibliometric analysis of spinal deformity's technological literature.

PURPOSE: Bibliometric analyses have gained popularity for studying scientific literature, but their application to evaluate technological literature (patents) remains unexplored. We conducted a bibliometric analysis on the top 100 most-cited patents in scoliosis surgery. METHODS: Multiple databases were queried using The Lens to identify the top 100 scoliosis surgery patents, which were selected based on forward patent citations. These patents were then categorized into 8 groups based on technological descriptors and assessed based on various factors including earliest priority date, year issued, and expiration status. RESULTS: The top 100 most-cited patents included technology underlying anterolateral tethering and distraction systems (n = 11), posterior tethering and distraction systems (n = 23), posterior segmental bone anchor and rod engagement systems (n = 29), interbody devices (n = 10), biological and electrophysiological agents for scoliosis treatment and/or improved arthrodesis (n = 8), intraoperative arthroplasty devices (n = 5), orthotic devices (n = 12), and implantable devices for non-invasive, postoperative alterations of skeletal alignment (n = 2). Seventy-five patents were expired, 21 are still active, and 4 were listed as inactive. The late 1970s and early 2000s saw increased numbers of patent filings. Demonstrated trends showed no meaningful correlation between patent rank and earliest priority date (linear trendline y = 0.2648x - 477.27; R2 = 0.0114), while a very strong correlation was found between patent rank and citations per year (power trendline y = 118.82x--0.83; R2 = 0.8983). CONCLUSION: Patent bibliometric analyses in the field of spinal deformity surgery provide a means to assess past advancements, better understand what it takes to make a difference in the field, and to potentially facilitate the development of innovative technologies in the future. The method described is a reliable and reproducible technique for evaluating technological literature in our field.

Ten-Year Experience of Skip Anterior Cervical Corpectomy and Fusion.

BACKGROUND: Anterior cervical corpectomy and fusion (ACCF) is often required to adequately decompress the spinal cord in patients with multilevel cervical spondylosis. Unfortunately, multilevel corpectomy constructs have high rates of early failure and frequently require supplemental posterior fixation. First described in 2003, skip ACCF (sACCF) is defined by corpectomies above and below an intervening vertebral body, which serves as an additional fixation point to augment biomechanical stability. Subsequent studies report high fusion rates and low construct failure rates secondary to superior biomechanical stability. OBJECTIVE: The goal of this study was to demonstrate the safety and efficacy of sACCF in the largest series published to date. METHODS: This study was a retrospective case series of all patients who underwent sACCF at a single institution over a 10-year period. Standard demographic and perioperative data were collected. Outcome data included immediate postoperative complications, long-term reoperation, and pre- and postoperative radiographic parameters. RESULTS: Forty-five patients underwent sACCF: 42 at C4-C6 and 3 at C5-C7. Mean age was 57.5 years. More than half (64.4%) of patients were smokers. Almost all patients were discharged home, the vast majority (82.2%) within 3 days of surgery. Five patients (11.1%) developed complications during the index hospitalization: 2 C5 palsies and 3 medical complications. Three patients (6.7%) developed instrumentation failure requiring anterior revision and supplemental posterior fixation. There were statistically significant increases in C1-C7 (47.8 vs 41.1, P < 0.001) and C2-C7 lordosis (11.1 vs 5.0, P < 0.001) on postoperative radiographs compared with preoperative imaging. Average follow-up was 21.1 months. CONCLUSION: sACCF can be performed safely with complication rates similar to those reported for multilevel anterior cervical discectomy and fusion or adjacent segment ACCF. It should be considered for patients with multilevel cervical pathology for whom an anterior approach is favored. CLINICAL RELEVANCE: sACCF is an effective surgical technique for multilevel cervical decompression and correction of cervical alignment.

Adverse events in neurosurgery and their relationship to quality improvement.

Adverse events are common in neurosurgery. Their reporting is inconsistent and widely variable due to nonuniform definitions, data collection mechanisms, and retrospective data collection. Historically, neurosurgery has lagged behind general and cardiac surgical fields in the creation of multi-institutional prospective databases allowing for benchmarking and accurate adverse event/outcomes measurement, the bedrock of evidence used to guide quality improvement initiatives. The National Neurosurgery Quality and Outcomes Database has begun to address this issue by collecting prospective, multi-institutional outcomes data in neurosurgical patients. Once reliable outcomes exist, various targeted quality improvement strategies may be used to reduce adverse events and improve outcomes.

Robotic approaches to the posterior spine.

STUDY DESIGN: This anatomic study described robotic approaches to the posterior thoracolumbar spine in a porcine model. Ergonomics, control, and approach and technical difficulties were noted. OBJECTIVE: The objective of this study was to develop a robotic approach to the posterior thoracolumbar spine maximizing surgeon ergonomics and control. SUMMARY OF BACKGROUND DATA: Surgery is both physically and mentally demanding, and strains from ergonomics and the aging process may negatively impact surgical skills. In spine surgery, control and precision are extremely important due to the close proximity to the spinal cord. The da Vinci robotic surgery system has offered better ergonomics and control in urology, gynecology, and cardiac surgery, and is rapidly gaining adoption. To date, there have been no published reports of da Vinci robotic spine surgery, motivating us to assess its potential in posterior spine surgery. METHODS: Posterior spine da Vinci approaches were tested on a pig without spinal pathology with an open subperiosteal dissection. A laser instrument and prototype robotic burr and rongeur instruments were tested on laminotomy, laminectomy, disc incision, and dural suturing procedures. RESULTS: Open dissection of the posterior spine provided sufficient access to successfully perform laminotomy, laminectomy, disc incision, and dural suturing procedures. Prototype burr and rongeur instruments were effective with good control. The laser instrument coagulated the epidural venous plexus and incised the anulus. Robot ergonomics allowed the surgeon to perform procedures for a full day with significantly less fatigue and reduced hand tremor. CONCLUSION: The da Vinci could perform the major noninstrumented procedures of the posterior spine with improved ergonomics and control. Surgeon fatigue and tremor were reduced. With some modification of prototype and commercial instruments a posterior spine surgery instrument kit can be developed. Future clinical studies can better assess patient and surgeon benefits of using the da Vinci robot for posterior spine surgeries.

Transpedicular decompression and pedicle subtraction osteotomy (eggshell procedure): a retrospective review of 59 patients.

STUDY DESIGN: Outcomes of transpedicular decompression and/or osteotomy were analyzed retrospectively. OBJECTIVES: To determine the effectiveness of decompression and correction, fusion stability, procedural safety, neurologic outcome, complication rates, and overall patient outcomes. SUMMARY OF BACKGROUND INFORMATION: The "eggshell" procedure is reserved for complex reconstructive problems in the treatment of acute trauma, deformity, tumor, or infection. The technique encompasses a range of procedures from simple transpedicular decompression and posterior fusion to more complex procedures, including transpedicular vertebrectomy and strut-grafting or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. These procedures are completed through a single posterior midline incision, with anterior spinal canal decompression a transpedicular approach, accompanied by a posterior or posterolateral fusion and internal fixation. METHODS: From 1990 to 1998, 59 "eggshell" procedures were performed for 37 deformity cases and 22 tumor or infection cases. Forty-two patients had a minimum 2-year follow-up, averaging 4.5 +/- 2.5 years. Thirty-six patients were available for patient interview, physical examination, and radiographic analysis. Outcome data were collected using SF-36 and SRS instruments. RESULTS: No patients worsened neurologically, and all incomplete spinal cord injuries improved. All patients achieved solid fusion radiographically. Correction with osteotomy averaged 26 degrees. Systemic complication rates were low with a pulmonary complication rate of 5%. Blood loss averaged 2342 mL. Overall patient outcomes were below population norms, but patient satisfaction was very high. CONCLUSION: Overall, the results suggest that the "eggshell" procedure is a reliable and safe technique to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach.