The proposed advantages of total disc replacement (TDR) over fusion in the lumbar spine are the preservation of motion and the avoidance of adjacent-level disease. One of the complications inherent in TDR is the possibility of vertebral body fracture due to trauma or a malpositioned implant. The resulting dilemma is that posterior decompression of the displaced bone fragment could then have a destabilizing effect and possibly require fusion, thus obviating the benefit of an arthroplasty procedure. In this study, the authors describe the technical considerations and feasibility of the treatment of a postoperative L-5 paresis that resulted from a dislocated bone fragment at L4–5 during a 2-level lumbar TDR.
Ralf Wagner, Menno Iprenburg and Albert E. Telfeian
Ziya L. Gokaslan, Albert E. Telfeian and Michael Y. Wang
Albert E. Telfeian, Dennis D. Spencer and Anne Williamson
Object. The purpose of this study was to determine whether intrinsic neuronal properties and synaptic responses differed between interictally active and inactive tissue removed in neocortical resections from patients undergoing surgical treatment for epilepsy.
Methods. Whole-cell patch recordings were performed in layer 2 or 3 and layer 5 pyramidal cells in neocortical slices obtained from tissue surgically removed from patients for the treatment of medically intractable seizures. Synaptic responses to stimulation at the layer 6—white matter border were used to classify cells as nonbursting if they responded with only a single action potential for all above-threshold stimuli (80%). These responses were usually followed by biphasic inhibitory postsynaptic potentials (IPSPs). Cells were classified as bursting if they fired at least three action potentials in response to synaptic stimulation (20%). These cells typically showed no IPSPs and responded in either an all-or-nothing or graded fashion. Approximately twice as many cells at layer 2 or 3 (29%) than cells at layer 5 (14%) fired synaptic bursts. Synaptic bursting was not associated with an alteration in a cell's response properties to γ-aminobutyric acid. It was notable that, in tissue samples determined by electrocorticography (ECoG) to be either interictally active or not active, the proportion of cells that burst was exactly the same in both groups (24%). We found no cells with intrinsic burst firing.
Conclusions. We conclude that synaptic bursting was characteristic of a small proportion of cells from epileptic tissue; however, this did not correlate with interictal spikes on ECoG.
Mitchell Hardenbrook, Sergio Lombardo, Miles C. Wilson and Albert E. Telfeian
The authors describe a cadaveric analysis to determine the ideal dimensions and trajectory for considering endoscopic transforaminal interbody implantation.
The soft tissues of 8 human cadavers were removed from L-1 to the sacrum, exposing the posterior bony elements. Facetectomies were performed bilaterally at each lumbar level with resection of the pars interarticularis, revealing the pedicles, nerve roots, and interbody disc space. Each level was digitally photographed with a marker for scale and evaluated with digital analysis software. The traversing and exiting nerve roots and pedicle margins were identified, and the distances between these structures and their relationships to the surrounding structures were documented.
The dimensions of 2 areas were measured: the working triangle and safe zone. The working triangle is the triangle between the exiting and traversing nerve roots above the superior margin of the inferior pedicle. The safe zone is the trapezoid bounded by the widths of the superior and inferior pedicles between the exiting and traversing nerve roots. The mean surface area for the working triangle was 1.83 cm2, with L5–S1 having the largest area at 2.19 cm2. The mean surface area of the safe zone was 1.19 cm2, with L5–S1 having the largest area at 1.26 cm2. At the medial border of the pedicle extending superiorly, there were no nerve structures within 1.19 cm at any level. On the lateral border of the pedicle, the exiting nerve root was closer superiorly, with the closest being 0.3 cm.
The working triangle is a relatively large area. The safe zone, just superior to the pedicle, is free of nerve structures. By utilizing the superior border of the pedicle, the disc space can be accessed within this safe zone without risk of injury to the nerves. A thorough understanding of foraminal anatomy is fundamental for considering how to safely access the disc space, thereby utilizing less invasive endoscopic techniques, and is an important first step in considering what shapes and sizes of interbody implants and retractors are feasible for use in the foramen.
Menno Iprenburg, Ralf Wagner, Alexander Godschalx and Albert E. Telfeian
The aim of this study was to describe patient radiation exposure during single-level transforaminal endoscopic lumbar discectomy procedures at levels L2–5 and L5–S1.
Radiation exposure was monitored in 151 consecutive patients undergoing single-level transforaminal endoscopic lumbar discectomy procedures. Two groups were studied: patients undergoing procedures at the L4–5 level or above and those undergoing an L5–S1 procedure.
For the discectomy procedures at L4–5 and above, the average duration of fluoroscopy was 38.4 seconds and the mean calculated patient radiation exposure dose was 1.5 mSv. For the L5–S1 procedures, average fluoroscopy time was 54.6 seconds and the mean calculated radiation exposure dose was 2.1 mSv. The average patient radiation exposure dose among these cases represents a 3.5-fold decrease compared with the senior surgeon's first 100 cases.
Transforaminal lumbar endoscopic discectomy can be used as a minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a herniated lumbar disc without the significant concern of exposing the patient to harmful doses of radiation. One caveat is that both the surgeon and the patient are likely to be exposed to higher doses of radiation during a surgeon's early experience in minimally invasive endoscopic spine surgery.
Albert E. Telfeian, Anand Veeravagu, Adetokunbo A. Oyelese and Ziya L. Gokaslan
Few neurosurgeons practicing today have had training in the field of endoscopic spine surgery during residency or fellowship. Nevertheless, over the past 40 years individual spine surgeons from around the world have worked to create a subfield of minimally invasive spine surgery that takes the point of visualization away from the surgeon's eye or the lens of a microscope and puts it directly at the point of spine pathology. What follows is an attempt to describe the story of how endoscopic spine surgery developed and to credit some of those who have been the biggest contributors to its development.
Albert E. Telfeian, Gabriele P. Jasper, Adetokunbo A. Oyelese and Ziya L. Gokaslan
In this study the authors describe the technical considerations and feasibility of transforaminal discectomy and foraminoplasty for the treatment of lumbar radiculopathy in patients who have herniated discs at the thoracolumbar junction.
After institutional review board approval, charts from 3 consecutive patients with lumbar radiculopathy and T12–L1 herniated discs who underwent endoscopic procedures between 2006 and 2014 were reviewed.
Consecutive cases (n = 1316) were reviewed to determine the incidence and success of surgery performed at the T12–L1 level. Only 3 patients (0.23%) treated with endoscopic surgery for their herniated discs had T12–L1 herniated discs; the rest were lumbar or lumbosacral herniations. For patients with T12–L1 disc herniations, the average preoperative visual analog scale score was 8.3 (indicated in the questionnaire as describing severe and constant pain). The average 1-year postoperative visual analog scale score was 1.7 (indicated in the questionnaire as mild and intermittent pain).
Transforaminal endoscopic discectomy and foraminotomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a thoracolumbar disc herniation.
Kleopas A. Kleopa, Leslie N. Sutton, Joseph Ong, Gihan Tennekoon and Albert E. Telfeian
✓ This 7-year-old boy with Dejerine—Sottas syndrome caused by a mutation in the myelin protein zero gene began to suffer rapid deterioration with increasing leg weakness, loss of the ability to ambulate, and bowel and bladder incontinence. Magnetic resonance imaging of the spine revealed nerve root hypertrophy resulting in compression of the conus medullaris and cauda equina. Decompressive surgery was successful in reversing some of his deficits.
John A. Boockvar, Matthew F. Philips, Albert E. Telfeian, Donald M. O'Rourke and Paul J. Marcotte
Object. Stabilization of the cervicothoracic junction (CTJ) requires special attention to the operative approach and biomechanical requirements of the fixation construct. In this study the authors assess the morbidity associated with the anterior approach to the CTJ and define risks that may lead to construct failure after anterior CTJ surgery.
Methods. Data obtained for 14 patients (six men and eight women, mean age 50.1 years) who underwent surgical stabilization of the CTJ via an anterior cervical approach were retrospectively reviewed to assess the anterior approach—related morbidity and the risks of construct failure. The mean follow-up period was 21.1 months. Four patients (29%) had previously undergone CTJ surgery; in 11 patients (64%) more than one motion segment was involved (two levels, six patients; three levels, four patients; four levels, one patient); allograft was placed in three (21%) of 14 graft sites; and anterior plates were used for reconstruction augmentation in eight patients (57%). Postoperatively all patients improved, although four patients had residual deficits or pain. Graft/plate failure, requiring surgical revision and/or halo placement, occurred in five patients (36%). One patient experienced transient recurrent laryngeal nerve palsy. Postoperatively, the authors classified patients into one of two groups: those in whom surgery was successful (nine cases) and those in whom it had failed (five cases). Analysis of the characteristics of these two groups revealed that male sex (p < 0.0365), multiple levels of involvement (p < 0.0378), and the use of allograft as compared with autograft (p < 0.0088) were significant risk factors for construct failure. Prior CTJ surgery (p < 0.053) tended to be associated with graft failure.
Conclusions: Findings of this study, in the setting of these factors, indicate that anterior reconstruction alone may not meet the biomechanical needs of this spinal region and that supplementary fixation may be considered to augment stabilization for fusion success.
Albert E. Telfeian, Alex Judkins, Donald Younkin, Avrum N. Pollock and Peter Crino
✓This 17-year-old male patient with tuberous sclerosis developed increased headaches and lethargy. Magnetic resonance imaging of the brain revealed increased ventricle size and increased size of a subependymal giant cell astrocytoma at the foramen of Monro, as well as spinal cord metastases of giant cell tumors. Decompressive surgery of the foramen of Monro lesion resulted in temporary resolution of the hydrocephalus. Increased Ki-67 labeling of tumor as well as rare spinal enhancement both possibly indicated malignant features for this entity.