Lumbar spinal stenosis: treatment options.
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Humans↗
Biomedical subjects
H N Herkowitz
Publications and source records attributed to H N Herkowitz.
1999 Cervical Spine Research Society Presidential Address: leadership and mentoring: its importance to our future.
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Cervical Vertebrae↗
Resident and fellowship guidelines: educational guidelines for resident training in spinal surgery.
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Curriculum↗
Effect of anular repair on the healing strength of the intervertebral disc: a sheep model.
STUDY DESIGN: The intervertebral disc, in a sheep model, was used to assess the effect of directly repairing three different anular incisions on the subsequent healing strength of the intervertebral disc. OBJECTIVES: To assess whether directly repairing an anular defect, made at the time of lumbar discectomy, could influence the healing rate and strength of the anulus fibrosus. METHODS: Twenty-four sheep underwent a retroperitoneal approach to five lumbar disc levels. An anular incision, followed by partial discectomy was done at each exposed level. Anular incisions used in this study consisted of 1) a straight transverse slit, 2) a cruciate incision, and 3) a window or box excision. Healing strength was measured at three time intervals: 2 weeks, 4 weeks, and 6 weeks. Each anular incision type was performed on 30 lumbar discs, 10 discs in each time interval. Five discs in each time interval underwent direct repair, and five discs were left unrepaired to heal as controls. The sheep were killed at 2, 4, and 6 weeks after surgery. The lumbar spines were removed en bloc, and the intervertebral discs were subjected to pressure-volume testing to assess the anular strength of repaired versus unrepaired disc injuries at each time interval. RESULTS: Statistical analysis was performed to evaluate the effects of healing time, incision technique, and repair on the pressure-volume characteristics of the involved discs. Pressure-volume testing showed trends of stronger healing for repaired discs, but at no time interval was any significant difference found between repaired and nonrepaired anular strength. Of the nonrepaired discs, the box incision was only 40 to 50% as strong as the slit or cruciate incised discs during early healing. CONCLUSION: Direct repair of anular incisions in the lumbar spine does not significantly alter the healing strength of the intervertebral disc after lumbar discectomy.
Animals↗
Cervical spondylotic myelopathy and radiculopathy.
Appropriate management of degenerative cervical spine conditions requires careful elucidation of the presenting clinical syndrome. Because of the pervasiveness of degenerative changes in asymptomatic patients, a clear correlation of symptoms, physical signs, and imaging findings is required before any specific diagnosis can be made. At this time, surgery is not recommended for prophylactic decompression in asymptomatic patients or in those patients with neck pain in the absence of extremity symptoms. In most patients with radiculopathy or mild myelopathy, a trial of nonsurgical management is recommended. Ultimately, patients with neurologic complaints and in whom nonsurgical measures have failed, as well as those with more pronounced myelopathy, should be offered surgical intervention. Selection of the safest, yet sufficient, approach requires a clear understanding of the benefits and expected outcomes. The outlook for patients with both cervical radiculopathy and early myelopathy is good. Radicular symptoms usually improve, but gait and hand changes may not. LF is preferred in younger patients with posterolateral or lateral soft disk herniations, or focal foraminal osteophyte impingement and predominance of upper extremity symptoms. More central 1- or 2-level pathology should be treated with ACDF. Anterior cervical corpectomy should be entertained in patients with nondisk level encroachment and in those with 3 contiguous levels of pathology. This approach is also required in cases of kyphosis and instability. Laminoplasty is indicated in patients with 4 or more levels of stenosis, particularly in those with global conditions such as continuous OPLL or congenital stenosis. In these patients, kyphosis or severe deformity may be addressed with a circumferential approach.
Cervical Vertebrae↗
Spinal stenosis.
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Decompression, Surgical↗
Complication, survival rates, and risk factors of surgery for metastatic disease of the spine.
STUDY DESIGN: The risk factors for complications and complication and survival rates in patients with metastatic disease of the spine were reviewed. A retrospective study was performed. OBJECTIVES: To determine the surgical complication and survival rates of patients with metastatic disease of the spine and risk factors for complication occurrence. SUMMARY OF BACKGROUND DATA: The role of surgical intervention for patients with metastatic disease of the spine has been controversial. Several risk factors for surgical complications have been identified. Short survival times and high complication rates have failed to justify surgical intervention in many cases. METHODS: Patients (n = 80) undergoing surgical treatment for metastatic disease of the spine were reviewed. Surgical indications included progressive neurologic deficit, neurologic deficit failing to respond to, or progressing after, radiation treatment; intractable pain; radioresistant tumors; or the need for histologic diagnosis. Patients underwent anterior, posterior, or combined decompression and stabilization procedures. Neurologic examination was recorded before surgery, postoperative period, and at least follow-up. Complication and survival rates were calculated. Several variables were examined for risk of complication. RESULTS: The mean age at time of surgery was 55.6 years (range, 20-84 years). Mean survival time after the diagnosis of spinal metastasis was 26.0 months (range, 1-107.25 months). Mean survival time after surgery was 15.9 months (range, 0.25-55.5 months). Sixty-five patients showed no change in Frankel grade, 19 improved one Frankel grade, and 1 deteriorated one Frankel grade; 1 patient had paraplegia. Thirty-five complications occurred in 20 patients (25.0%). Ten patients (12.5%) had multiple complications accounting for 23 of the 35 postoperative problems (65.7%). Sixty patients had no surgical complications (75%). There were no intraoperative deaths. CONCLUSIONS: The likelihood that a complication occurred was significantly related to Harrington classifications demonstrating significant neurologic deficits and the use of preoperative radiation therapy. In general, Harrington classifications with neurologic deficits and lower Frankel grades before and after surgery were associated with an increased risk of complication. Overall, the major complication rate was relatively low, and minor complications were successfully treated with minimal morbidity. The relatively long survival time after spinal surgery in this group of patients justifies surgical treatment for metastatic disease. Most complications occurred in a small percentage of patients. To minimize complications, patients must be carefully selected based on expected length of survival, the use of radiation therapy, presence of neurologic deficit, and impending spinal instability or collapse caused by bone destruction.
Adult↗
Management of degenerative disc disease above an L5-S1 segment requiring arthrodesis.
Clear guidelines exist for treating spondylolisthetic deformity and instability. How the surgeon handles adjacent-level degenerative disease is not as well established. Because magnetic resonance imaging now provides us with far more information on the "health" of radiographically normal intervertebral discs, the treatment of dehydrated or degenerated discs adjacent to a fusion is becoming more problematic. In this discussion, two experts discuss their approach to symptomatic lumbosacral spondolisthesis accompanied by adjacent-level disc degeneration. Drs. Herkowitz and Abraham believe strongly that the adjacent segment should be left alone, whereas Dr. Albert recommends extending the fusion in many instances.
Adult↗
The use of recombinant human bone morphogenetic protein 2 (rhBMP-2) to promote spinal fusion in a nonhuman primate anterior interbody fusion model.
STUDY DESIGN: A study on the efficacy of recombinant human bone morphogenetic protein 2 (rhBMP-2) in a nonhuman primate anterior interbody fusion model. OBJECTIVES: To investigate the efficacy of rhBMP-2 with an absorbable collagen sponge carrier to promote spinal fusion in a nonhuman primate anterior interbody fusion model. SUMMARY OF BACKGROUND DATA: RhBMP-2 is an osteoinductive growth factor capable of inducing new bone formation in vivo. Although dosage studies using rhBMP-2 have been performed on species of lower phylogenetic level, they cannot be extrapolated to the primate. Dosage studies on nonhuman primates are essential before proceeding with human primate application. METHODS: Six female adult Macaca mulatta (rhesus macaque) monkeys underwent an anterior L7-S1 interbody lumbar fusion. All six sites were assigned randomly to one of two fusion methods: 1) autogenous bone graft within a single freeze-dried smooth cortical dowel allograft cylinder (control) or 2) rhBMP-2-soaked absorbable collagen sponges within a single freeze-dried smooth cortical dowel allograft cylinder also soaked in rhBMP-2. The animals underwent a baseline computed tomography scan followed by 3- and 6-month postoperation scans. Anteroposterior and lateral radiographs of the lumbosacral spine were performed monthly. After the monkeys were killed, the lumbar spine fusion sites were evaluated. Histologic evaluation of all fusion sites was performed. RESULTS: The three monkeys receiving rhBMP-2-soaked collagen sponges with a freeze-dried allograft demonstrated radiographic signs of fusion as early as 8 weeks. The control animals were slower to reveal new bone formation. The computed tomography scans revealed extensive fusion of the L7-S1 lumbar vertebrae in the group with rhBMP-2. A pseudarthrosis was present in two of the control animals. CONCLUSIONS: This study was able to document the efficacy of rhBMP-2 with an absorbable collagen sponge carrier and a cortical dowel allograft to promote anterior interbody fusion in a nonhuman primate model at a dose of 0.4 mg per implant site (1.5 mg/mL concentration). The late of new bone formation and fusion with the use of rhBMP-2 and cortical dowel allograft appears to be far superior to that of autogenous cancellous iliac crest graft with cortical dowel allograft.
Animals↗
The role of prophylactic antibiotics in spinal instrumentation. A rabbit model.
STUDY DESIGN: A rabbit model was used to test the efficacy of cefazolin administered in various therapeutic regimens in preventing iatrogenic Staphylococcus aureus infections during spinal instrumentation. OBJECTIVE: To assess the efficacy of various prophylactic therapeutic regimens of cefazolin in preventing iatrogenic S. aureus infections during spinal instrumentation. SUMMARY OF BACKGROUND DATA: Previous studies have not dealt specifically with the occurrence of iatrogenic S. aureus infections during spinal instrumentation in a prospective fashion. METHODS: Twenty New Zealand White rabbits underwent a posterior approach to the lumbar spine. Fifteen of the animals then had double-braided 26-gauge surgical wire placed around bilateral L3-L4 and L4-L5 facet joints. A standardized volume of a 103 S. aureus/mL of solution was then inoculated onto the fusion-hardware site in all rabbits. The rabbits were divided into four groups receiving various antibiotic dose regimens. Five days after surgery, the animals were killed, and cultures were obtained. RESULTS: All of the rabbits receiving no antibiotic had fusion sites infected with S. aureus. None of the animals who received prophylactic cefazolin produced cultures that grew S. aureus. A specimen from one fusion site cultured Staphylococcus epidermidis, which is not sensitive to cefazolin. Analysis of these data using Fisher's exact test resulted in a P value of 0.008 when results in antibiotic groups were compared with those in a group receiving no antibiotics and a P value of 0.0003 when all groups were compared. CONCLUSIONS: This model was valid and reproducible for the study of spinal instrumentation and infection. In addition, the data support the efficacy and use of prophylactic intravenous antibiotics in preventing infection in spinal instrumentation and fusion surgery.
Animals↗
Computed tomography-guided biopsy of the spine. A review of 103 patients.
STUDY DESIGN: A retrospective study of 103 computed tomography-guided biopsies of the spine. These represent a consecutive series of patients with spinal lesions or disorders observed over a 32-month period. OBJECTIVES: To determine the diagnostic accuracy and clinical usefulness of computed tomography-guided biopsies with respect to major influencing variables. SUMMARY OF BACKGROUND DATA: Computer tomographic-guided biopsy of the spine is considered a safe, accurate, and relatively inexpensive examination technique. A study comparing its diagnostic accuracy with respect to all the variables of age, gender, radiographic appearance, spinal level, tissue type, or pathologic diagnosis has not been done. METHODS: Biopsy specimens were sent for cytologic and histologic analysis. Bacteriologic studies were performed when clinically indicated. The biopsy results were analyzed for adequacy and diagnostic accuracy, i.e., the ability to generate a tissue sample adequate for pathologic examination and one that yields diagnostic information. RESULTS: The mean age of patients was 60 years, with a range of 4-91 years. The spines of 52 males and 51 females were studied. There were eight cervical, 28 thoracic, 53 lumbar, and 14 sacral lesions used as biopsy sites. The radiographic appearance of spinal lesions were lytic in 74 cases, blastic in four cases, and mixed in two cases. Tissues undergoing biopsy included bone (63 cases), soft tissue (35 cases), and mixed specimens (five cases). The pathologic examinations revealed 18 infections, 23 primary neoplasms, 34 metastases, and 19 normal tissues. An adequate specimen for pathologic examination was obtained in 90 biopsies (87%). A diagnosis was achieved in 67 of 94 patients (71%). Diagnostic rates obtained in thoracic level biopsies were lower than those from biopsies of other spinal levels (P = .007). CONCLUSION: Computed tomography-guided biopsy is an important tool in the evaluation of spinal lesions. A positive biopsy result may preclude the need for open surgical intervention. This study included one of the largest series of patients in the medical literature. In addition, it determined the diagnostic rates of this procedure with respect to the major influencing variables. Thoracic-level biopsies have a diagnostic rate that is significantly lower than that of other spinal levels. No significant correlation was found between diagnostic accuracy and age, gender, radiographic appearance, tissue type, or eventual diagnosis.
Adolescent↗
Indications and trends in use in cervical spinal fusions.
Anterior cervical decompression and arthrodesis has evolved over the last 40 years and has become the preferred procedure for managing many cervical spine disorders. The first half of this article discusses the indications for cervical fusion in the management of traumatic, degenerative, neoplastic, infectious, and congenital conditions of the cervical spine. The second half of this article discusses the recent trends in use of cervical spine fusions that demonstrate the increasing frequency of this procedure in the United States over the last 10 years.
Bone Plates↗
Indications for thoracic and lumbar spine fusion and trends in use.
Over the last 10 years, the annual number of spinal procedures performed in the United States has more than doubled. In 1996, there were roughly 29,000 thoracic or dorsal fusion procedures, which made up almost 13% of all spine fusions performed. Scoliosis was the most common condition necessitating posterior thoracic fusion. The first half of this article focuses on the indications for thoracic and lumbar fusions; whereas, the second half of this article discusses the trends in use of thoracic and lumbar spine fusions.
Humans↗
1997 Volvo Award winner in clinical studies. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation.
STUDY DESIGN: This prospective study analyzed the influence of transpedicular instrumented on the operative treatment of patients with degenerative spondylolisthesis and spinal stenosis. OBJECTIVES: To determine whether the addition of transpedicular instrumented improves the clinical outcome and fusion rate of patients undergoing posterolateral fusion after decompression for spinal stenosis with concomitant degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Decompression is often necessary in the treatment of symptomatic patients who have degenerative spondylolisthesis and spinal stenosis. Results of recent studies demonstrated that outcomes are significantly improved if posterolateral arthrodesis is performed at the listhesed level. A meta-analysis of the literature concluded that adjunctive spinal instrumentation for this procedure can enhance the fusion rate, although the effect on clinical outcome remains uncertain. METHODS: Seventy-six patients who had symptomatic spinal stenosis associated with degenerative lumbar spondylolisthesis were prospectively studied. All patients underwent posterior decompression with concomitant posterolateral intertransverse process arthrodesis. The patients were randomized to a segmental transpedicular instrumented or noninstrumented group. RESULTS: Sixty-seven patients were available for a 2-year follow-up. Clinical outcome was excellent or good in 76% of the patients in whom instrumentation was placed and in 85% of those in whom no instrumentation was placed (P = 0.45). Successful arthrodesis occurred in 82% of the instrumented cases versus 45% of the noninstrumented cases (P = 0.0015). Overall, successful fusion did not influence patient outcome (P = 0.435). CONCLUSIONS: In patients undergoing single-level posterolateral fusion for degenerative spondylolisthesis with spinal stenosis, the use of pedicle screws may lead to a higher fusion rate, but clinical outcome shows no improvement in pain in the back and lower limbs.
Aged↗
Spinal instrumentation in the management of degenerative disorders of the lumbar spine.
The use of spinal instrumentation as an adjunct to fusion for the treatment of degenerative disorders of the lumbar spine is controversial. Instrumented lumbar fusions, in specific instances, may improve patient outcomes. For patients undergoing single level primary lumbar arthrodesis, the available data do not conclusively support the efficacy of spinal instrumentation. However, in the setting of previous failed lumbar surgery, iatrogenic or degenerative lumbar spondylolisthesis, spinal instrumentation may be useful as an adjunct to fusion. Possible advantages associated with the use of instrumentation include: correction of deformity in frontal and sagittal planes; decreased pseudarthrosis rates; prevention of progression of spondylolisthesis, and provision of spinal stability in the absence of intact posterior elements. Complications associated with the use of instrumentation include: increased cost; increased operative times; increased infection rate; increased reoperation rate; and a steep learning curve. Therefore, when instrumentation is to be used, the benefits must outweigh the risks. These risks can be minimized by the judicious use of instrumentation by experienced surgeons, for specific indications as supported by the literature.
Discitis↗
Augmentation of autograft using rhBMP-2 and different carrier media in the canine spinal fusion model.
This study evaluated the use of recombinant human bone morphogenetic protein (rhBMP-2) with various types of carrier media, and the effect of rhBMP-2 as an adjunct to autogenous iliac crest bone graft in the canine spinal fusion model. BMP induces mesenchymal cells to differentiate into cartilage and bone. The recent availability of rhBMP-2 has created the opportunity to evaluate this material's properties in augmenting autogenous bone graft in spinal fusion. Currently, the most appropriate type of carrier media for rhBMP-2 is undetermined. Bilateral intertransverse spinal fusions were performed on six canine lumbar spines at L1-L2, L3-L4, and L5-L6, using autogenous posterior iliac crest bone graft at each level, creating a total of 18 segmental fusion sites. All 18 sites were then randomly assigned to one of six fusion methods: autogenous bone graft (ABG) alone, ABG + rhBMP-2, ABG + collagen (Helistat) "sandwich" + rhBMP-2, ABG + collagen (Helistat) morsels + rhBMP-2, ABG + polylactic/glycolic acid sponge (PLGA) sandwich + rhBMP-2, and ABG + open-pore polylactic acid morsels + rhBMP-2. Each material was evaluated for ease of handling and application at the index surgery. The animals underwent computed tomography (CT) scanning of the lumbar fusion sites after 8 weeks. Volumetric measurements of total fusion mass at each level were performed using two-dimensional CT scan slices and a volumetric program supplied by the Siemens Medical System. The animals were killed after imaging studies. The lumbar spine fusion sites were evaluated for integrity of the fusion mass, both visually and with manual mechanical stressing. Crossover of the fusion mass to adjoining levels was also evaluated. Histologic evaluation of all fusion sites was performed. The addition of rhBMP-2 significantly increased bone graft volume as noted on CT scan. Carrier that could be mixed with morselized bone graft offered easier handling and application and all spine segments fused. Polylactic/glycolic acid (PLGA) sites were associated with a greater incidence of voids within the fusion mass. No significant difference in carrier media for rhBMP-2 could be determined. However, PLGA was associated with a higher rate of fusion mass void formation. rhBMP-2, when added to autograft, significantly increased the volume and the maturity of the resulting fusion mass.
Animals↗
Is pathology examination of disc specimens necessary after routine anterior cervical discectomy and fusion?
STUDY DESIGN: A retrospective chart review was performed from 1990-1994. OBJECTIVES: To evaluate the outcome of pathologic examination of cervical disc specimens submitted after anterior cervical discectomy. SUMMARY OF BACKGROUND DATA: This study is the first to review the outcome of pathologic examination of disc specimens after anterior cervical discectomy and fusion. METHODS: Charts were reviewed based on the procedure code of anterior cervical fusion and the main diagnoses of cervical disc and spondylosis. The following data were recorded for each patient: symptoms, examination, diagnostic studies, operative procedure, operative findings, and pathology report. Statistical analysis was performed. RESULTS: Five hundred six disc levels in 394 patients were reviewed. All patients had symptoms and examination results consistent with cervical radiculopathy. All patients had cervical radiographs and some combination of myelography, computed tomography, or magnetic resonance imaging. Findings at the time of surgery included the presence of either a herniated disc or degenerative spondylitic changes. The pathologic examination results of all specimens reported fibrocartilaginous tissue consistent with disc material with the presence of degenerative changes. No infectious, benign, or malignant process was identified at the time of surgery or on gross and histologic examination of any of the disc specimens. Using confidence intervals (95%) for exact proportions and given 500 negatives, the chance the next occurrence would be positive would be 0.0060 or 0.60% or six of 1000. CONCLUSIONS: This study shows that if the symptoms, physical examination, radiographic diagnostic studies, and surgical findings are consistent with those of cervical disc herniation of spondylosis, the chance of an unexpected, clinically important pathologic finding within the disc specimen is extremely small. The time and expense involved in routine pathologic examination of cervical disc specimens can be avoided.
Cervical Vertebrae↗
Efficacy of closed wound suction drainage after single-level lumbar laminectomy.
The use of closed suction drainage after spinal surgery remains controversial. The purpose of this study was to determine the indications for closed suction drainage after single-level lumbar surgery. Two hundred patients who were scheduled to undergo single-level lumbar surgery without fusion were prospectively randomized into two groups. One group had a closed wound suction drain placed deep to the lumbodorsal fascia before routine closure, whereas the second group had no drain placed. Hemostasis was achieved in all patients before the surgeon had knowledge of the randomization outcome. All drains were removed on the 2nd postoperative day, and the amount of drainage was recorded. After surgery, the patients were evaluated for signs and symptoms of continued wound drainage, hematoma/seroma formation, and/or infection as well as evidence of an acquired neurologic deficit. One hundred three patients had a drain placed before closure and two patients developed postoperative wound infection, both of which were successfully treated with orally administered antibiotics. Of the 97 patients who had no drain placed after the surgical procedure, one patient developed a postoperative wound infection that was treated with surgical incision and drainage, as well as intravenously administered antibiotics. Statistical analysis revealed that the presence or absence of a drain did not affect the postoperative infection rate. No new neurologic deficits occurred in any postoperative patient. The use of drains in single-level lumbar laminectomy without fusion did not affect patient outcome. There was no significant difference in the rate of infection or wound healing and no patient developed a postoperative neurologic deficit.
Adult↗