Percutaneous nucleotomy. An alternative to spinal surgery

The past, present, and the future of disc nucleus replacement. A systematic review of a large diversity of ideas and experiences

Disc nucleus replacement (NR) is a challenging surgical technique used as a medical treatment for early-stage disc herniation to restore disc height and the biomechanical function of a motion segment, which may reduce low back pain. The surgical procedure involves the removal and replacement of the degenerated nucleus pulposus with a substitute by accessing the annulus fibrosos via a created hole. Over the decades, nucleus replacement has been an important issue, leading to the development of different substitute alternatives. The first ideas are dated to the 1950s and since then, more than a hundred nucleus replacement concepts can be identified. There were numerous attempts and several clinical trials; however, after more than 70 years of research, no gold standard for nucleus pulposus replacement has been identified. This review aims to collect the different nucleus replacements reported in the literature, thus understanding what failed, what could be improved and what are the opportunities for the future. A systematic review of the literature was performed using a keyword-based search on PubMed, Web of Science, and Scopus databases to detect all nucleus replacements presented in the past by clinicians and engineers. Several studies were extracted from which the main nucleus replacements over the years were investigated, including the ones that received CE mark, FDA approval, or IDE approval and, also those involved in clinical trials. A total of 116 studies were included in this review. The extracted data concern the nucleus replacements proposed over the years to create a historical background as complete as possible, including their mechanical and biomechanical characterization and the clinical trials conducted over the years. Nucleus disc arthroplasty has been explored for many years. Unfortunately, even today there is still nothing safe and definitive in this surgical practice. This review provides an overview of the nucleus replacement history. A breakthrough could be the improvements in technologies for the annulus fibrous closing or sealing and the tissue engineering and medical regenerative techniques which could certainly ensure a higher NR implantation success rate in the future of this clinical treatment. It is not yet clear what is the future of this clinical practice. Only scientific research can answer the question: is the nucleus replacement still a possible clinical solution?

Background, techniques, applications, current trends, and future directions of minimally invasive endoscopic spine surgery: A review of literature

Across many of the surgical specialties, the use of minimally invasive techniques that utilize indirect visualization has been increasingly replacing traditional techniques which utilize direct visualization. Arthroscopic surgery of the appendicular skeleton has evolved dramatically and become an integral part of musculoskeletal surgery over the last several decades, allowing surgeons to achieve similar or better outcomes, while reducing cost and recovery time. However, to date, the axial skeleton, with its close proximity to critical neural and vascular structures, has not adopted endoscopic techniques at as rapid of a rate. Over the past decade, increased patient demand for less invasive spine surgery combined with surgeon desire to meet these demands has driven significant evolution and innovation in endoscopic spine surgery. In addition, there has been an enormous advancement in technologies that assist in navigation and automation that help surgeons circumvent limitations of direct visualization inherent to less invasive techniques. There are currently a multitude of endoscopic techniques and approaches that can be utilized in the treatment of spine disorders, many of which are evolving rapidly. Here we present a review of the field of endoscopic spine surgery, including the background, techniques, applications, current trends, and future directions, to help providers gain a better understanding of this growing modality in spine surgery.

Percutaneous Endoscopic Lumbar Discectomy for Lumbar Disc Herniation Using an Endoscopic Staining: A Technical Note

Symptomatic lumbar disc herniation (LDH) is widely treated using percutaneous endoscopic lumbar discectomy (PELD). In the present PELD surgery, performing decompression under endoscope still takes a long time to explore the rupture site of annulus fibrosus, resulting in prolonged operation time and over-invasion of the undegenerated annulus fibrosus. A wide range of intraoperative exploration also induces an iatrogenic injury of the normal annulus fibrosus, even aggravating intervertebral disc degeneration, which may lead to early postoperative recurrence in severe case. Hence, it is important to seek a precise decompression in PELD surgery. Under this kind of realization, more spinal surgeons possibly choose a disc staining before performing decompression. However, the classical disc staining technique still has its shortcomings. First of all, an appropriate dose of staining cannot be accurately mastered, even induces unqualified staining effect. Second, the duration of surgery and the times of fluoroscopy will be increased. Finally, what surgeons see under the endoscope is the staining result but not the staining process. Hence, this is accomplished more effectively by designing procedures that perform fully visible disc staining under spinal endoscope. There is no specific research to discuss the technique note of endoscopic staining in PELD surgery. We have come up with a new original technology of endoscopic staining with methylene blue injection in PELD for treatment of LDH.

Short- and long-term results of percutaneous full-endoscopic and microsurgical lumbar discectomy: prospective cohort study

Objective. To analyze immediate and long-term results of percutaneous endoscopic and microsurgical discectomy.

Material and Methods. A prospective cohort study in two groups of patients was conducted in 2015–2018. The observation period was 6–42 months. Group 1 included 110 patients who underwent percutaneous endoscopic lumbar discectomy, and Group 2 – 331 patients who underwent microdiscectomy. Efficiency was assessed using NRS-11, ODI, SF-36, and MacNab questionnaires.

Results. The operating time, bed day number, and disability period were shorter in Group 1 (p < 0.001). The average effective dose of radiation exposure to the patient was 4.4 mSv in transforaminal endoscopy, and 0.8 mSv in interlaminar and microsurgical discectomy. There were no significant intergroup differences in frequency and types of complications and reoperations. The portion of symptomatic hernia recurrence in Group 1 was 10 %, in Group 2 – 4.8 %. Significant differences in neurological outcomes and quality of life were not revealed. Good and excellent outcomes according to MacNab criteria were noted in 78.2 % and 84.9 %, in Groups 1 and 2, respectively.

Conclusion. The percutaneous endoscopic discectomy allows reducing hospital stay length and disability period, while having clinical efficacy equal to that of other disectomy methods. A statistically insignificant increase in the risk of hernia recurrence after percutaneous endoscopic discectomy was noted.

Evolution of Spinal Endoscopic Surgery

Innovations in the development of endoscopic spinal surgery were classified into different generations and reviewed. Future developments and directions for endoscopic spinal surgery were discussed. Surgical therapy for spinal disease has been gradually changing from traditional open surgery to minimally invasive spinal surgery. Recently, endoscopic spinal surgery, which initially was limited to the treatment of soft tissue lesions, has expanded to include other aspects of spinal disease and good clinical results have been reported. As the paradigm of spinal surgery shifts from open surgery to endoscopic surgery, we discussed the evolution of endoscopic spine surgery in our literature review. Through this description, we presented possibilities of future developments and directions in endoscopic spine surgery.

A brief history of endoscopic spine surgery

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.

The importance of preserving disc structure in surgical approaches to lumbar disc herniation

STUDY DESIGN

This study examined the clinical and radiographic results in patients with lumbar disc herniation treated surgically with one of four procedures: two different methods of herniotomy using a posterior approach and two different methods of percutaneous nucleotomy.

OBJECTIVES

The authors goal was to identify the structural changes in the disc after each of the procedures and to correlate them with the clinical outcome.

SUMMARY OF BACKGROUND DATA

The details of herniotomy procedure via a posterior approach or by percutaneous nucleotomy as described by many authors have not been consistent. Furthermore, previous reviews of these studies have been less than satisfactory.

METHODS

One hundred fifty-seven herniotomies using a posterior approach and 94 percutaneous nucleotomies were studied with a follow-up of at least 2 years. Each of these groups was divided into two subgroups to evaluate the role of the remaining nucleus pulposus in the central area of the disc.

RESULTS

Changes seen in imaging studies, such as a decrease in disc height and an increase of intervertebral instability in plain radiographs and a decrease in signal intensity of the disc in magnetic resonance images, were significantly less common in the subgroups of herniotomy and percutaneous nucleotomy in which the nucleus pulposus in the central area of the disc was preserved when compared with the subgroups in which a complete removal of the disc was attempted. The changes seen in the imaging studies were significant in patients younger than 40 years of age and correlated closely with the clinical results.

CONCLUSIONS

Preserving the nucleus pulposus during the surgical treatment of lumbar disc herniation in patients younger than 40 years of age resulted in better radiographic and clinical results.

Percutaneous endoscopic discectomy: surgical technique and preliminary results compared to microsurgical discectomy

Percutaneous endoscopic discectomy is a new technique for removing "contained" lumbar disc herniations (those in which the outer border of the anulus fibrosus is intact) and small "noncontained" lumbar disc herniations (those at the level of the disc space and occupying less than one-third of the sagittal diameter of the spinal canal) through a posterolateral approach with the aid of specially developed instruments. The technique combines rigid straight, angled, and flexible forceps with automated high-power suction shaver and cutter systems. Access can thus be gained to the dorsal parts of the intervertebral space where the disc herniation is located. Percutaneous endoscopic discectomy is monitored using an endoscope angled to 70 degrees coupled with a television and video unit and is performed with the patient under local anesthesia and an anesthesiologist available if needed. Its indication is restricted to discogenic root compression with a minor neurological deficit. Two groups of patients with contained or small noncontained disc herniations were treated by either percutaneous endoscopic discectomy (20 cases) or microdiscectomy (20 cases). Both groups were investigated in a prospective randomized study in order to compare the efficacy of the two methods. The disc herniations were located at L2-3 (one patient), L3-4 (two patients), or L4-5 (37 patients). There were no significant differences between the two groups concerning age and sex distribution, preoperative evolution of complaints, prior conservative therapy, patient's occupation, preoperative disability, and clinical symptomatology. Two years after percutaneous endoscopic discectomy, sciatica had disappeared in 80% (16 of 20 patients), low-back pain in 47% (nine of 19 patients), sensory deficits in 92.3% (12 of 13 patients), and motor deficits in the one patient affected. Two years after microdiscectomy, sciatica had disappeared in 65% (13 of 20 patients), low-back pain in 25% (five of 20 patients), sensory deficits in 68.8% (11 of 16 patients), and motor deficits in all patients so affected. Only 72.2% of the patients in the microdiscectomy group had returned to their previous occupation versus 95% in the percutaneous endoscopic discectomy group. Percutaneous endoscopic discectomy appears to offer an alternative to microdiscectomy for patients with "contained" and small subligamentous lumbar disc herniations.

Percutaneous nucleotomy with CT and fluoroscopic guidance

Automated percutaneous diskectomy was performed with use of computed tomographic (CT) and fluoroscopic monitoring. Degenerative disease of the intervertebral disk was treated with local administration of anesthesia and use of a nucleotome. One hundred ten patients with neurologic symptoms and morphologic changes of one segment were selected for treatment. Previous conservative therapy had been unsuccessful. Patients with completely prolapsed and sequestered fragments of herniated disks ("uncontained disk"), narrow intervertebral spaces, posterior osteophytes, diseased facet joints, and spinal stenoses were not considered candidates for percutaneous nucleotomy (PNT). After PNT, 82% of the patients had complete remission of their neurologic symptoms; Lasègue sign was negative or improved in 92%. In 18% (20 patients), the symptoms did not improve sufficiently; 11% (12 of 110) of these patients underwent surgical nucleotomy. There were no serious complications, in particular, no injuries to vital structures (nerves, thecal sac, arteries, veins), except for one case of spondylodiskitis. Guiding PNT with CT and fluoroscopy provides a safe procedure with good clinical results. The addition of CT has shortened the operation but increased over-all procedure time. In the future, a shift to outpatient treatment may offset the additional time and cost of including CT guidance.

Lumbar percutaneous discectomy. Initial experience in 28 cases

Since November 1988, 28 patients with lumbar L5 radiculopathy refractory to conservative care and with a radiologically verified central or mediolateral disc herniation at the level of L4/L5 had had a percutaneous discectomy. Radiological verification consisted of spinal CT +/- myelography, +/- myelo-CT, +/- MRI. A short-term follow-up analysis of at least 2 months taking the clinical and functional status as well as the professional reintegration into account revealed a 64.3% (18/28 patients) satisfactory outcome and a 32.1% (10/28 patients) failure rate. Of the latter 28.6% (8/28 patients) required further open surgery. One patient whose pain had only partially in regressed was shown at open operation to have a sequestered cranial prolapse as revealed by spinal CT after the percutaneous procedure. There were no major complications. One patient developed a sequestered extraforaminal herniation through the nucleotomy canal three weeks after the procedure. One patient bled for 2 minutes. There were no major vessel injuries. One patient reported local muscular pain, and enhanced nerve root pain after introduction of the trocar sleeve.

Automated percutaneous lumbar discectomy

Lumbar spine disc disease has traditionally been treated surgically by laminectomy and manual removal of the offending disc material. Chymopapain was extensively used to decompress the disc pressure in a relatively noninvasive manner, but has been abandoned due to serious complications, including anaphylaxis and paraplegia. Onik introduced automated percutaneous discectomy in 1985. This procedure has proved safe and efficacious for treating lumbar disc disease without complications. It is performed on an out-patient basis under local anesthesia with minimal rehabilitation time. The success rate reported in a multiinstitutional study with one year follow-up is approximately 75%. The majority of failures occur in patients with free fragments or spinal stenosis - both of which can be diagnosed preoperatively with good imaging examinations. Hence, the success rate can be expected to improve if preoperative imaging is relied upon to help choose appropriate patients. Over 30,000 percutaneous discectomy procedures have been performed. The only complication reported, disc infection, developed in fewer than 0.2% of cases. Automated percutaneous discectomy has the potential to treat a vast number of patients with lumbar disc disease who otherwise would have laminectomies.