Long-term Clinical Outcomes After Bilateral Laminotomy or Total Laminectomy for Lumbar Spinal Stenosis

A Single-institution Experience

Andrea Pietrantonio, MD; Sokol Trungu, MD; Isabella Famà, MD; Stefano Forcato, MD; Massimo Miscusi, MD, PhD; Antonino Raco, MD, PhD

Disclosures

Neurosurg Focus. 2019;46(5):e2 

In This Article

Methods

Patient Population

We retrospectively reviewed all the patients treated surgically by the senior author (A.R.) for DLSS with total laminectomy and bilateral laminotomy; only the patients followed up for a minimum of 10 years and with complete clinical and radiological documentation were selected and are the subject of this study. Considering the progressive transition from the classic open procedures to minimally invasive approaches, we selected 2 time intervals, the first one (2000–2003) in which the classic laminectomies were routinely used and the second one (2005–2008), in which bilateral laminotomies were considered the procedure of choice by our group for the treatment of DLSS. We analyzed only the surgeries performed by the senior author, and we do not restrict our analysis to a single period in which both the procedures were performed, thus preventing the selection bias of considering one procedure more adequate than the other one during the surgical decision-making process. In fact, from 2005 we treated our patients almost exclusively with bilateral laminotomies, even when a severe compression was detected, whereas the use of lumbar laminectomies was restricted mainly to neoplastic and traumatic compressions.

Patients reviewed in the present study showed similar demographic data and comparable comorbidities and were divided into 2 treatment groups (total laminectomy, group 1; and bilateral laminotomy, group 2) according to the surgical decompression technique.

The diagnosis of LSS was made based on lumbar MRI or CT scanning (if MRI could not be done), if a single or multilevel compression was detected; flexion-extension radiographs were always performed to rule out any spine instability. From a clinical point of view, leg pain, leg numbness, and neurogenic claudication were considered more indicative than back pain, as well as improvement of symptoms during flexion of the trunk. Symptoms were considered refractory to nonsurgical treatment if conservative measures, particularly nonsteroidal antiinflammatory drugs and physical therapies, had been administered for at least 3 months without improvement.

For the purposes of this study, we excluded patients with previous spine surgery or fractures, spine instability, lumbar degenerative spondylolisthesis, degenerative scoliosis, developmental spinal deformities, neoplastic compression, and severe osteoporosis.

Preoperative clinical evaluation data were obtained from medical charts. Postoperative (3 weeks) and follow-up scores were obtained during outpatient visits or phone interviews 6, 24, 60, and 120 months after surgery.

During the follow-up interviews, patients were asked about preoperative, immediate postoperative, and current status; improvement in symptoms; use of painkillers; patient satisfaction; and current therapy. Pain was measured according to a self-assessment 10-point visual analog scale (VAS).

The 36-Item Short-Form Health Survey (SF-36) and Oswestry Disability Index (ODI) were administered postoperatively (3 weeks) and at 6, 24, 60, and 120 months after surgery. The SF-36 mental health and physical functioning summaries were analyzed in detail. The clinical outcomes were analyzed and statistical analyses performed with SPSS software v.15 (IBM Corp.). A p value < 0.05 was considered significant.

Operative Technique

All procedures were performed under general anesthesia; patients were placed prone on a Jackson spinal table with a Wilson frame support in a marked flexed position to reduce lumbar lordosis and increase the interlaminar space.

Conventional Laminectomy (group 1). A 6-cm-long midline linear skin incision is made; the lumbodorsal fascia is incised vertically and the multifidus muscle is detached subperiosteally on each side and bilaterally retracted.

At the index level, the spinous process, the laminae, and the ligamentum flavum are resected. The medial portion of the facet joints (< one-third of the entire facet joint) is then removed bilaterally (facet-sparing laminectomy) to decompress the lateral recesses, using a high-speed drill and Kerrison rongeurs; foraminotomy is performed bilaterally. At the end of the decompression, suction drains are routinely placed; patients are generally allowed to walk with a corset brace within 2 days of surgery, and the use of a corset brace is recommended for 4–6 weeks.

Bilateral Laminotomy (group 2). A 4-cm-long midline linear skin incision is made. The multifidus muscle from each side is detached from its attachments, the interlaminar space is exposed, and the retractors are applied.

With the aid of the surgical microscope, the upper and lower laminae at the index level are bilaterally thinned: the basal part of the spinous process, the caudal half of the cranial lamina, and a small cranial portion of the caudal lamina are then removed bilaterally by using a small Kerrison rongeur, starting from the upper lamina at the midline and then proceeding laterally. Care is taken not to detach the spinous process completely and to preserve the hypertrophied ligamentum flavum as long as possible for the protection of the dural sac and nerve roots during the osseous decompression. Following adequate bony resection, the ligamentum flavum is removed with a curette; partial resection of the facet joints and foraminotomy are usually done bilaterally to increase the neural decompression.

Generally, the intervertebral disc is not removed because in DLSS the compression acts mainly posteriorly and the preservation of the anterior stabilizing structures of the spine (intervertebral disc, posterior longitudinal ligament) is advisable. Suction drains are not routinely placed. Ambulation is encouraged on the day of surgery, and the use of a corset brace is not recommended.

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