Benedikt W. Burkhardt

Smith-Robinson Procedure with an Autologous Iliac Crest for Degenerative Cervical Disc Disease: A 28-Year Follow-Up of 95 Patients

BACKGROUND Long-term clinical results after anterior cervical discectomy and fusion (ACDF) with an autologous iliac crest are rare. The purpose of this study was to assess this, with special focus on pain, functional outcome, and repeat surgery for adjacent segment disease (ASD). METHODS Hospital records of 212 patients who were affected by degenerative cervical disc disease and treated by the Smith-Robinson technique were reviewed. Information about diagnosis, surgery, pre- and postoperative clinical process, and complications was analyzed. Patients were reviewed with a standardized questionnaire including the current neurologic status, Neck Disability Index, EQ-5D, Patient Satisfaction Index, Odom criteria, and limitations in quality of life. RESULTS Ninety-five patients with a mean follow-up of 28 years were evaluated. ACDF was performed at 1 level in 67 and 2 levels in 28 patients. Ninety-two patients reported pain before surgery and 68 patients remained pain free and did not require second surgery. At follow-up, the mean Neck Disability Index was 14%, and mean EQ-5D score was 5. Postoperatively, 96.8% of patients were satisfied and 84.2% of patients reported good to excellent functional recovery. One patient had a hairline fracture at the iliac crest donor site. Fourteen patients underwent second surgery because of degenerative changes, including 11 at the symptomatic ASD. CONCLUSIONS ACDF yields significant decrease in pain, a significant increase in function, and a high degree of patient satisfaction. Overall prevalence for ASD was 12.0% after 25 years. Patients with reoperation had similar clinical outcome regarding pain, compared with patients without reoperation.

Influence of Prior Cervical Surgery on Surgical Outcome of Endoscopic Posterior Cervical Foraminotomy for Osseous Foraminal Stenosis

BACKGROUND Posterior cervical foraminotomy is a valuable option as a treatment for cervical radiculopathy caused by osseous foraminal stenosis. Here the authors present their technique and results in a series of patients with and without previous surgery. METHODS Forty-five patients suffering from cervical osseous foraminal stenosis were operated on via a microendoscopic posterior approach with the EasyGO system. All procedures were video recorded and afterwards retrospectively analyzed. The primary evaluation criterion was prior surgery or no prior surgery. Additionally, postoperative outcome according to Odoms criteria and Neck Disability Index (NDI), reoperation rate, and complications was considered. RESULTS The 45 patients of this study showed an overall clinical success rate of 84%. There was no emergency stopping of any endoscopic procedure. Twenty patients (44.4%) had no and 25 patients (55.6%) had previous cervical surgery. In patients without previous surgery, the clinical success rate was 95.2%; NDI was 12%; and 100% of patients reported reduction of their preoperative arm pain and motor recovery. In patients with previous surgery, the clinical success rate was 75%. NDI was 24%. Most patients (91.7%) reported reduction of their preoperative arm pain, and 66.7% reported recovery of motor strength. CONCLUSION This retrospective analysis shows that microendoscopic posterior cervical foraminotomy is a successful option in the treatment of osseous cervical foraminal stenosis. Nevertheless, clinical success in patients with previous surgery is much lower compared with patients without previous surgery. Thus, a more thorough clinical workup is recommended to identify the patients who are not going to benefit before subsequent surgical procedures.

The visualization of the surgical field in tubular assisted spine surgery: Is there a difference between HD-endoscopy and microscopy?

OBJECTIVE Expert spinal surgeons criticized endoscopic procedures for poor image quality, in comparison to microscopic visualization. The recent introduction of high definition (HD) digital cameras has shown good results in spinal endoscopy. The aim of this study was to assess endoscopic HD image quality in comparison with microscopic visualization. PATIENTS AND METHODS All posterior lumbar and cervical spinal surgeries of this study were performed with the EasyGO-system in HD resolution. For each comparison, anatomical structures were predefined intraoperatively. A junior resident was randomly required to enter the operating theatre and to identify those structures either using HD-endoscopic or microscopic visualization through the endoscopic working sheath. RESULTS Thirteen lumbar and three cervical procedures were performed. Thirty-four comparisons with a total of 214 predefined anatomical structures were analyzed. The number of predefined structures ranged from 5 to 9 per surgical field. Out of 214 predefined structures, 124 structures (65.8%) were correctly identified under endoscopic view and 88 (41.1%) under microscopic view (p=0.001). Subjective impression of visualization quality were rated 1.25 (very good) for endopscopic images and 1.6 (very good to good) for microscopic view (p=0.02). CONCLUSIONS When using a working trocar and live images, endoscopic HD camera imaging accounted for significantly more reliable identifications of anatomical structures compared to the microscopic view. The subjective impression of video quality is significantly better with HD-optics. The goal of further studies should be to evalute if these findings results in improved surgical outcome.

311 Smith-Robinson Procedure With an Autologous Iliac Crest Bone Graft With and Without Caspar Plating as a Treatment for Soft Cervical Disc Herniation: Report of 122 Patients With an Average Follow-up of 25 Years.

INTRODUCTION The purpose was to evaluate the long-term clinical outcome for the surgical treatment of cervical disc herniation. Special focus was given to assess pain, functional outcome, and symptomatic adjacent segment disease (ASD) after anterior cervical discectomy and fusion (ACDF) and ACDF with Caspar plating (ACDF+PS). METHODS Hospital records of 226 patients who were affected by soft cervical disc herniation and treated by ACDF or ACDF+PS were reviewed. Information about diagnosis, procedure, pre- and postoperative clinical process, and complications were analyzed. Patients were reviewed with a standardized questionnaire including the current neurological status, Neck Disability Index (NDI), EQ-5D, Patient Satisfaction Index, Odom criteria, and limitations in quality of life. Special interest was pointed out to symptomatic adjacent segment disease and reoperation. RESULTS One-hundred twenty-two patients with a mean follow-up of 25 years were evaluated. Eight had ACDF and 42 had ACDF+PS. Seventy-eight patients had single-level surgery, 40 had 2-level surgery, and 4 patients had 3-level surgery. In 89.3% patients with preoperative pain reported to be free of pain at follow-up. The mean NDI is 14%, mean EQ-5D-score was 5, according to Odom criteria 86.1% of patients had a good to excellent functional recovery, according to the PSI 98.4% of patients were satisfied or very satisfied. There was no significant difference between patients who were operated via ACDF and patients operated via ACDF+PS concerning EQ-5D, NDI, Odom, PSI, rate of patients without pain, and rate of reoperation due to degenerative changes. Thirteen patients underwent a second surgery because of degenerative changes among those 9 due to symptomatic ASD. CONCLUSION The overall prevalence for symptomatic ASD was 8.4% after more than 25 years. ACDF and ACDF+PS yields significant decrease in pain, increase in function even after more than 20 years. There are no statistical differences concerning pain reduction, functional outcome, and rate of reoperation due to degenerative changes.

Management of Dural Tears in Endoscopic Lumbar Spinal Surgery: A Review of the Literature

OBJECTIVE The incidental dural tear is a common complication in lumbar spine surgery. It has been reported that the incidence of dural tears is much greater in endoscopic procedures. Primary closure via suturing remains challenging in endoscopic procedures. The objective of this study was to conduct a literature review on the surgical technique for dural closure and repair in endoscopic spine surgery. METHODS A systematic literature search was performed using the database PubMed. In total, 12 studies reported specifically about the surgical treatment for dural tear in percutaneous and tubular assisted endoscopic technique. The dural tear rate, the technique of dural closure, postoperative time of bed rest, postoperative symptoms related to cerebrospinal fluid fistula, and revision surgery were assessed. RESULTS The overall rate of dural tears in endoscopic spinal surgery was 2.7%, with a range from 0% to 8.6%. The incidence of a dural tear was much greater in cases with lumbar stenosis (3.7%) than in lumbar disc herniation (2.1%). The greatest rate was accompanied by resecting synovial cysts. In addition, the risk of dural tear is greater in bilateral decompression procedures via a unilateral approach. There is no consensus about the ideal technique for dural closure in endoscopic procedures. Furthermore, there is a debate whether dural tear requires surgical treatment or not. CONCLUSIONS An autologous muscle or fat graft in combination with fibrin glue or a fibrin-sealed collagen sponge seems to be a good and safe method for the management of dural tear in lumbar endoscopic spine surgery.

The Learning Process of Endoscopic Spinal Surgery for Degenerative Cervical and Lumbar Disorders Using the EasyGO! System

BACKGROUND Among spinal surgeons, the safety of endoscopic spinal techniques has been criticized as the result of a prolonged learning curve and divergent surgical technique from traditional microsurgery. In this manuscript, the authors assessed the learning curve of 4 experienced microsurgical neurosurgeons in endoscopic spinal surgery. METHODS Retrospectively, the surgical reports, the endoscopic video recording, and the files of all patients who underwent an endoscopic procedure for the treatment of cervical and lumbar disc herniation from January 2011 to December 2017 were reviewed. The learning process was assessed via several parameters: surgical time, intraoperative complications, dural tear, nerve root injury, conversion to microsurgery, new postoperative neurologic deficits, repeated procedure, and early recurrent disc herniation. RESULTS The learning process of for 4 surgeons was assessed on the basis of 308 procedures. The mean surgical time for the initial procedure ranges from 58 to 97 minutes and improved to 51-85 minutes for the last procedures. A shorter surgical time had no influence on the rate of intraoperative complication and repeated procedure. Increased working space had a significant influence on the surgical time. The number of procedure to reach the asymptote varied from 10 to 20 depending on the endoscopic system and the surgeon. CONCLUSIONS The learning process in endoscopic tubular-assisted spinal surgery is variable, and the asymptote might be reached after 10-20 procedures. The amount of working space and instrument angulation affects the surgical time. The decrease of surgical time had no significant influence on the rate of intraoperative complication and repeated procedures.

Is there an impact of cervical plating on the development of adjacent segment degeneration following Smith-Robinson procedure? A magnetic resonance imaging study of 84 patients with a 24-year follow-up

BACKGROUND CONTEXT Anterior cervical discectomy and fusion (ACDF) without and with cervical plating (ACDF+CP) are accepted surgical techniques for the treatment of degenerative cervical disc disorders. The effect of CP on the development of adjacent segment degeneration (ASD) remains unclear. PURPOSE To assess whether CP accelerates the degeneration of the adjacent and adjoining segments. STUDY DESIGN/SETTING This is an imaging cohort study. PATIENT SAMPLE Retrospectively, a total of 84 patients who underwent ACDF or ACDF+CP were identified. At final follow-up, an MRI was performed and evaluated in this study. MATERIALS AND METHODS An MRI of 84 patients who underwent ACDF (46 patients) and ACDF+PS (38 patients) was performed. The mean follow-up was 24 years (17-45 years). None of the patients had a repeat procedure in the cervical spine. The grade of degeneration of the segments adjacent and adjoining to the fusion was assessed via a five-step grading system (segmental degeneration index, or SDI) that includes disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis. Furthermore, the disc height (DH) and sagittal segmental angle (SSA) of fused segments were measured. RESULTS A significantly (p<.001) greater SDI was identified at the caudal adjacent segment following ACDF compared to ACDF+CP. No other significant differences were identified in patients following ACDF and ACDF+CP. Between 50% and 96% of all segments showed severe degenerative changes according to SDI. There was no significant difference in DH between the patients following ACDF and ACDF+CP. The SSA in patients who underwent ACDF+CP was significantly greater than in the ACDF patients (p=.002). CONCLUSIONS In this cohort of patients, cervical plating had no significant impact on segmental degeneration and decrease of DH in the adjacent and adjoining segments. ACDF+CP seem to preserve the lordotic alignment more with respect to the SSA than ACDF.

Adjacent Segment Degeneration After Anterior Cervical Discectomy and Fusion With an Autologous Iliac Crest Graft: A Magnetic Resonance Imaging Study of 59 Patients With a Mean Follow-up of 27 Years

BACKGROUND Anterior cervical decompression and fusion (ACDF) is a widely accepted surgical technique for the treatment of degenerative disc disease. ACDF is associated with adjacent segment degeneration (ASD). OBJECTIVE To assess whether physiological aging of the spine would overcome ASD by comparing adjacent to adjoining segments more than 18 yr after ACDF. METHODS Magnetic resonance imaging of 59 (36 male, 23 female) patients who underwent ACDF was performed to assess degeneration. The mean follow‐up was 27 yr (18‐45 yr). Besides measuring the disc height, a 5‐step grading system (segmental degeneration index [SDI]) including disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis was used to assess the grade of adjacent and adjoining segments. RESULTS The SDI of cranial and caudal adjacent segments was significantly higher compared to adjoining segments (P < .001). The disc height of cranial and caudal adjacent segments was significantly lower compared to adjoining segments (P < .001, P < .01). The SDI of adjacent segments in patients with repeat cervical procedure was significantly higher than in patients without repeat procedure (P = .02, P = .01). The disc height of the cranial adjacent segments in patients with repeat procedure was significantly lower than in patients without repeat procedure (P = .01). CONCLUSION The physiological aging of the cervical spine does not overcome ASD. The disc height and the SDI in adjacent segment are significantly worse compared to adjoining segments. Patients who underwent repeat procedure had even worse findings of disc height and SDI.

Endoscopy in Cervical Spine Surgery

The first evidence of spinal surgery was found in Egyptian mummies 2900 BC [1]. In the antiquity, about 2500 years later, Hippocrates who is considered “The father of spine surgery” collected a valuable heritage of knowledge and methodology about the human body. He was the first who described sciatica and low-back pain. He also proposed a traction procedure and invented devices based on his fundamental principle [2]. Concerning the cervical spine, Aulus Celsus was the first who noted death following injury of the cervical spinal cord [3]. Paulus of Aegina performed the first operative repair of injured spinal cord by removing bony fragments which irritated the spinal cord and caused consecutive paralysis in the seventh century [3]. It took spinal surgery about 1900 years until an endoscope was applied. In 1983, the first report of an examination technique for intervertebral disc space after nucleotomy via endoscopy/arthroscopy was described by Frost and Hausmann [4]. Since then new surgical technology and techniques for minimally invasive approaches have revolutionized the work of surgeons of all subspecialties. Procedures such as laparoscopic cholecystectomy and orthopedic arthroscopy have proven to decrease surgically related morbidity, shorten postoperative hospital time and improve clinical outcomes [5–7]. In spinal surgery, morbidity is associated with iatrogenic muscle and soft tissue injury due to approach and exposure of the surgical field. Particularly in lumbar spine surgery, the standard open approach leads to iatrogenic injury of the paraspinal muscles which might result in decreased muscle strength and muscle atrophy after extensive muscle retraction [8, 9]. Biomechanical studies have investigated the function of the posterior column and its importance in maintaining lumbar spinal stability [10, 11]. Serial tube dilators and retractors were designed to split the back muscle gently and thus made to minimize retraction and disruption of the paraspinal muscular integrity. Further, other studies demonstrated that the postoperative recovery of CK and CRP levels occurred within 1 week and that the intensity of low back pain was mild [12, 13]. Mayer et al. studied the postoperative muscle architecture on CT scan and its relevance for failed-back syndrome [8]. They found that the integrity of paraspinal muscles might be of utmost importance for the postoperative result. A tubular retraction system provides direct and focal access to the diseased anatomy via a less invasive approach [14, 15]. Surgery can be done by using either an endoscope or using a microscope for visualization. The microendoscopic technique for interlaminar fenestration is considered safe and effective treatment of degenerative lumbar spine diseases and makes this to be seen as an option along with the traditional technique for every spine surgeon [16].