Post laminectomy instability
Introduction
“We must, if possible, attempt to extract by an incision the compressing bone.” This description of the first laminectomy by Paul of Aegina, a 7th century Greek physician, highlights one of the core tenets of spine surgery, decompression.1 In 1829, A.G. Smith performed the first documented successful laminectomy on a patient who had fallen from a horse.2 The majority of spine surgeries in the 19th century were decompressions in the setting of infection, trauma, or tumor; laminectomy for degenerative conditions did not occur until the turn of the 20th century.2 In 1954, Verbiest detailed the constellation of symptoms associated with lumbar spinal stenosis (LSS) and the positive results he achieved following laminectomy in seven patients suffering from this condition.3 Laminectomy quickly became the gold standard for surgical treatment of lumbar spinal stenosis.
While short-term results appeared favorable, the long-term efficacy of laminectomy remained controversial.4, 5, 6, 7, 8 Iatrogenic instability induced by removal of the posterior stabilizing elements has been cited as a potential cause for deterioration of positive outcomes over time.9 However, in their 1975 paper on the treatment of spinal stenosis, renowned surgeons Wiltse, Kirkaldy–Willis, and McIvor stated: “We seldom do fusion even if all the posterior stability has been lost. Olisthesis will rarely occur where the disease process is degenerative disk disease.”10 The challenge of balancing an adequate decompression without needlessly destabilizing the spine continues in the present era.
Section snippets
What is instability?
Spinal instability is a nebulous concept. In the biomechanical realm, spinal instability has been defined as excessive motion, pathologic motion— both increased or decreased—any motion causing abnormal load distribution, or loss of normal coupling patterns.11, 12 One of the most well known definitions of clinical spinal instability comes from White and Panjabi who defined it as a loss of the spine's ability to maintain its patterns of displacement under physiologic loads without neurologic
Biomechanics
Stability of the spinal column relies on the interplay between the spinal column components (disc, ligaments, and facet joints), the paraspinal muscles, and the neural control unit.11 The spinal column acts as a load bearer and transducer, relaying information regarding load, motion, and position to the neural control unit that in turn activates the appropriate spinal muscles to keep the spinal column within physiological normal parameters.
Biomechanical studies have demonstrated the importance
Incidence
Not all laminectomies are created equal. During the era of the radical or “Christmas tree laminectomy,” the incidence of postoperative anterolisthesis ranged from 43% to 55%.6, 9 In cases where facet-sparing laminectomies were performed, the incidence of spondylolisthesis ranges from 0–43%.6,20, 21, 22, 23, 24 A systematic review of 24 studies detailing the incidence of postoperative instability following decompression for LSS found a 5.5% incidence of new or worsening spondylolisthesis. The
Patient and radiographic risk factors
A variety of patient, radiographic, and surgical risk factors associated with instability following laminectomy have been identified. Multilevel laminectomies tend to be more destabilizing than single level laminectomies.20, 25 The female sex has been associated with higher rates of both degenerative spondylolisthesis and postoperative spondylolisthesis.9, 26 Increased ligamentous laxity and decreased bone mineral density are thought to be contributing factors to the increased instability seen
Surgical risk factors
Surgical techniques have evolved over time to allow for an adequate decompression while minimizing the disruption to surrounding stabilizing structures. The conventional laminectomy involves removal of the spinous process, supraspinous ligament, interspinous ligament, lamina, and portion of the facet joints. The laminotomy was developed in an attempt to preserve the midline structures and can be performed bilaterally, or unilaterally with bilateral decompression (ULBD).
Thome et al. randomized
Conclusion
Decompression, stabilization, and deformity correction are the three surgical means by which spine surgeons can help their patients. Out of concern for late deterioration of results following laminectomy for LSS, thought to be due in part to iatrogenic instability, our surgical techniques have evolved over the last century to feature procedures that allow for removal of a minimum of the stabilizing structures while still achieving an adequate decompression. While a variety of patient,
Disclosures
The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article.
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Cited by (4)
Surgical Management of Spinal Epidural Abscess in Elderly Patients: A Comparative Analysis Between Patients 65–79 Years and ≥80 Years with 3-Year Follow-Up
2022, World NeurosurgeryCitation Excerpt :Fox et al.41 suggested that radiologically confirmed secondary instability after spinal decompression is a common phenomenon that correlates with worse clinical outcomes or the necessity for additional fusion surgery. Patients with preoperative instability signs, such as preoperative anterolisthesis or abnormal motion on dynamic radiography, are at a greater risk of secondary instability after a spinal decompression procedure.42 In our study, the mean follow-up duration was >3 years, and no additional surgical procedures were performed due to secondary instability.
Full Endoscopic Lumbar Stenosis Decompression: A Future Gold Standard in Managing Degenerative Lumbar Canal Stenosis
2022, International Journal of Spine Surgery
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