Faculty Bibliography

Pedicle screw instrumentation is a widely used technique for fixating the spine in fusion surgery. One of the complications associated with pedicle screw placement is when a screw breaches the pedicle medially and causes the patient radicular pain or numbness or weakness. Revising a breached pedicle screw in a patient who has undergone a multilevel fusion surgery often requires that the patient undergo a very invasive revision surgical procedure. Here the authors present a technical note on decompressing an S1 nerve compressed by a breached pedicle screw by performing an endoscopic surgical approach through a 1-cm incision and drilling down the threads of the pedicle screw, directly decompressing the nerve without removing the screw.

OBJECTIVE:The natural history of degenerative disease after instrumented lumbar fusion can result in symptomatic radiculopathy at the adjacent segment. Here we describe our experience with transforaminal endoscopic decompression for the treatment of adjacent segment radiculopathy. METHODS:A technique for the transforaminal endoscopic treatment of lumbar radiculopathy adjacent to instrumented lumbar fusions is presented. Prospectively, we followed a series of 9 consecutive patients operated on with lumbar radiculopathy above (5) or below (4) their instrumented fusion. Preoperative and postoperative clinical data with 2-year follow-up are presented. RESULTS:A consecutive series of 9 patients who underwent transforaminal endoscopic treatment for lumbar radiculopathy adjacent to an instrumented spinal fusion between 2012 and 2014 is presented. Three patients required revision to fusion at 2, 13, and 19 months postoperatively. The mean visual analogue scale score for radicular pain improved from an average pain score before surgery of 8.4 to 1.3 1 year after surgery and the mean visual analogue scale for back pain improved from an average pain score before surgery of 8.0 to 4.7 1 year after surgery (excluding the 1 patient with 2month postoperative failure). CONCLUSIONS:Transforaminal endoscopic surgical access to adjacent level disease pathology may be a unique approach to the treatment of adjacent segment disease because it allows for neural decompression of disc and foraminal pathology without requiring significant destabilizing bone removal. However, the 2-year failure rate presented here is 33%, which indicates that the benefit of this technique may ultimately be temporary.

BACKGROUND:Transforaminal lumbar endoscopic discectomy is a minimally invasive spine surgery procedure performed principally for the treatment of lumbar herniated discs. Endoscopic spine surgeons around the world have noted how far patients will travel to undergo this minimally invasive spine surgery, but the actual distance patients travel has never been investigated. OBJECTIVE:We present here our analysis of how far patients will travel for endoscopic spine surgery by studying the referral patterns of patients to 3 centers in 3 different countries. STUDY DESIGN:Retrospective chart review of de-identified patient data was performed to analyze the distance patients travel for spine surgery. METHODS:Patient demographic data was analyzed for patients undergoing transforaminal lumbar endoscopic discectomy procedures over the same 8 month period in 2015 at centers in the United States (U.S.), Netherlands, and Germany. RESULTS:Travel distances for patients were determined for 327 patients. The average distance traveled for the U.S. center was 91 miles, the Dutch center was 287 miles, and the German center was 103 miles. For the U.S. center 16% of patients traveled out of state for surgery and for the European centers combined, 4% of patients traveled out of the country for surgery. LIMITATIONS:The period of data analyzed was less than one year and the data collected was analyzed retrospectively. CONCLUSIONS:Quality metrics in health care tend to be focused on how health care is delivered. Another health care metric that focuses more on what patients desire is presented here: how far patients will travel for innovative spine care.Key words: Endoscopic spine surgery, transforaminal, minimally invasive, travel, lumbar disc herniation.

The first academic program in endoscopic spine surgery in the United States opened its doors at Rhode Island Hospital in 2012. Published advances in the field since its inception have included treatments for a myriad of pathologies including lumbar and thoracic disc herniations, spondylolisthesis, spine tumors as well as treatments for complications of other spinal procedures including spinal fusion, kyphoplasty, and total disc replacement. In this issue of the Rhode Island Medical Journal we summarize the history of the procedure as well as some of the interesting progress going on in this field in Rhode Island. [Full article available at http://rimed.org/rimedicaljournal-2017-06.asp].

Lateral lumbar interbody fusion is a minimally invasive approach to anterior spinal column fusion, deformity correction, and indirect decompression of the lumbar spine. A rarely reported possible complication of the procedure is end plate fracture, which has the potential for nerve root compression. Here we present a case of end plate fracture and nerve compression after stand-alone lateral lumbar interbody fusion, its diagnosis, and its subsequent successful treatment with transforaminal endoscopic spine surgery. The case highlights the possible role for minimally invasive endoscopic surgery as a rescue procedure after fusion complication.

BACKGROUND:Lateral recess stenosis is a common pathology causing de-novo or residual radicular pain following lumbar spine surgery. Diagnostic criteria and treatment strategies for symptomatic lateral recess stenosis are not well established. METHODS:We identified ten patients in our prospective patient database (n=146) who underwent endoscopic interlaminar decompression for unilateral symptomatic lateral recess stenosis. Lateral recess height and angle were measured on axial T2-weighted MRI. Values from the symptomatic side were compared to the contralateral side which served as asymptomatic control. Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for back and leg pain were collected preoperatively, postoperatively and at last follow-up. RESULTS:postoperatively 1.7±0.9, P<0.05). The ODI improved from 50±5.8 preoperatively to 22.2±5.1 at last follow-up (P=0.001). One patient experienced persistent leg pain. CONCLUSIONS:Lateral recess height and angle correlate with symptomatic lateral recess stenosis which is effectively treated utilizing interlaminar endoscopic lateral recess decompression.

Posterior cervical foraminotomy is an effective surgical treatment method for relieving radicular symptoms that result from cervical nerve root compression. Minimally invasive techniques and tubular retractor systems are available to minimize tissue retraction, but minimally invasive approaches can carry with them the surgical challenge of trying to pass instruments through a long narrow retractor that is also the port for visualizing the surgical pathology. Herein, the authors present a case of a 65-year-old man who presented with symptoms of a left C6 and C7 radiculopathy and left C5-6 and left C6-7 foraminal narrowing on MRI. A minimally-invasive fully endoscopic left C5-6 and C6-7 posterior foraminotomy was performed through a 1cm outer diameter working channel endoscopic with a 6 mm working channel. Clinicians should be aware that new minimally invasive non-fusion approaches for the treatment of cervical radiculopathy that utilize endoscopic visualization are now coming into use in clinical practice.

Lumbar lateral recess stenosis that results from a degenerative bulging of the disc and overgrowth of the facet is a very common cause for lumbar radiculopathy in the elderly. The standard surgical treatment for symptomatic lumbar lateral recess stenosis often requires a laminectomy or hemi-laminectomy and medial facetectomy which can further destabilize a pathological motion segment. The authors present here a novel technique for contralateral endoscopic access to the lateral recess pathology that is truly minimally invasive and spares most of the facet joint complex: 6 patient cases are described where lateral recess stenosis pathology was accessed from a contralateral sublaminar endoscopic approach.

Tethered cord syndrome is a constellation of symptoms and signs that include back and leg pain, bowel and bladder dysfunction, scoliosis and lower extremity weakness and deformity. Tethering may be due to a tight filum terminale or a form of spinal dysraphism. The authors present a case of a 40-year-old man who presented with symptoms of back pain, bilateral lower extremity radicular pain, and bowel and bladder dysfunction. Magnetic resonance imaging showed a sacral lipomyelomeningocele, with fat tracking superiorly to the conus, which was tethered at the L4-L5 level. A minimally-invasive surgical approach with endoscopic visualization and identification of the nerve roots and filum terminale was performed. The patient's postoperative clinical course was uneventful. This case highlights two important issues. First, minimally invasive spine techniques should be considered in the surgical treatment of tethered cord especially given the theoretical advantages of minimizing pain, spinal fluid leakage, and subsequent scarring. And second, endoscopic techniques are advancing. In the case presented here, endoscopic visualization and operative techniques made identification and transection of the filum terminale possible through a tiny dural opening. The small dural opening could theoretically pose the advantage of decreasing the risk of spinal fluid leakage. Clinicians should be aware that endoscopic visualization and techniques can serve as minimally-invasive adjuncts to enhance the traditional approach to many surgical pathologies.

BACKGROUND AND IMPORTANCE:Cerebrospinal fluid shunt placement is used to treat the various causes of hydrocephalus by redirecting the cerebrospinal fluid to the body, most commonly from the ventricle to the peritoneum. Distal catheter displacement from the peritoneal cavity can occur as a complication, necessitating reoperation. CLINICAL PRESENTATION:We report 2 such cases in obese patients involving retropulsion of the distal tubing. To address this complication, we implanted a T-connector to the distal catheter construct. CONCLUSION:This study supports the use of a T-connector catheter construct to decrease and prevent the possibility of distal peritoneal catheter retropulsion in cases of elevated intra-abdominal pressure, both prophylactically and in revisions.