Evaluating the Evidence Behind the Surgical Treatment of Lumbar Stenosis Joseph Beshay, MD Assistant Professor of Neurological Surgery University of Texas Southwestern

Lumbar Stenosis Narrowing of the Spinal canal with encroachment on the neural structures by surrounding bone or soft tissue. Narrowing of the Spinal canal with encroachment on the neural structures by surrounding bone or soft tissue. Typical presentation: Radicular symptoms or neurogenic claudication. Typical presentation: Radicular symptoms or neurogenic claudication. Back pain common but not a result of lumbar stenosis per se. Back pain common but not a result of lumbar stenosis per se. May be asymptomatic May be asymptomatic Most common reason for lumbar surgery in adults over 65 Most common reason for lumbar surgery in adults over 65 Deyo et al. Spine 1993

Lumbar Stenosis

Treatment Treatment Surgical: Laminectomy / laminotomy / foraminotomy/ Open vs MIS technique, Interspinous process device, Extension limiting device, Interspinous decompression, “chimney” laminectomy…… Surgical: Laminectomy / laminotomy / foraminotomy/ Open vs MIS technique, Interspinous process device, Extension limiting device, Interspinous decompression, “chimney” laminectomy…… Non-Surgical: Epidural steroids, Physical therapy, NSAIDS, Narcotic analgesics, spinal manipulation, back exercises….. Non-Surgical: Epidural steroids, Physical therapy, NSAIDS, Narcotic analgesics, spinal manipulation, back exercises…..

Lumbar Stenosis In any given week I see at least one patient with ‘lumbar stenosis’ and at least one patient with ‘LOW BACK PAIN’ In any given week I see at least one patient with ‘lumbar stenosis’ and at least one patient with ‘LOW BACK PAIN’ Preconceived ideas………. Preconceived ideas……….

Lumbar Stenosis Thank you for seeing me today, Doctor I won’t take up much of your time If you can help with my leg pains, I would be thankful If you can’t help me, I thank you anyways I baked you this pie…

Back Pain

Hey! Fix my back pain. I want to be able to go bowling again! Don’t you tell me to lose weight! Hey! Refill my Lortab Fill out this stack of disability forms

Lumbar Stenosis The Evidence Treatment Treatment Where is the data? Where is the data? Paucity of head to head randomized trials Paucity of head to head randomized trials Many small non-randomized observational type studies. Many small non-randomized observational type studies. Most randomized studies are small Most randomized studies are small Two large studies Two large studies Maine Lumbar Spine Study Maine Lumbar Spine Study SPORT (Spine patients outcomes research trial) lumbar stenosis arm. SPORT (Spine patients outcomes research trial) lumbar stenosis arm.

Lumbar Stenosis Main Lumbar Spine Study Observational Study Observational Study Surgical vs Non-Surgical treatment determined by Surgeon and Patient Surgical vs Non-Surgical treatment determined by Surgeon and Patient 148 patients enrolled between patients enrolled between Excluded patients with prior lumbar surgery, cauda equina, fractures, infections, malignancies…etc. Excluded patients with prior lumbar surgery, cauda equina, fractures, infections, malignancies…etc. Reported results at 1, 4 and 10 years Reported results at 1, 4 and 10 years Atlas et al. Spine 2005

Lumbar Stenosis Main Lumbar Spine Study 97 patients available for follow-up 97 patients available for follow-up Surgical group had more severe baseline symptoms and worse functional status Surgical group had more severe baseline symptoms and worse functional status Leg pain relief and back related functional status favored surgery Leg pain relief and back related functional status favored surgery Low back pain relief similar between both groups Low back pain relief similar between both groups Atlas et al. Spine 2005

Lumbar Stenosis Main Lumbar Spine Study Atlas et al. Spine 2005

Lumbar Stenosis Main Lumbar Spine Study Atlas et al. Spine 2005

SPORT - Background The Spine Patient Outcomes Research Trial (SPORT) was designed to assess the relative efficacy and cost-effectiveness of surgical and non-surgical approaches to the treatment of common conditions associated with low back and leg pain. The Spine Patient Outcomes Research Trial (SPORT) was designed to assess the relative efficacy and cost-effectiveness of surgical and non-surgical approaches to the treatment of common conditions associated with low back and leg pain. Three arms studying lumbar HNP, Stenosis and degenerative spondylolisthesis Three arms studying lumbar HNP, Stenosis and degenerative spondylolisthesis 13 medical centers in 11 States 13 medical centers in 11 States Randomized as well as observational cohorts Randomized as well as observational cohorts Weinstein et al. NEJM 2008

SPORT – Lumbar Stenosis Inclusion Criteria Inclusion Criteria Neurogenic claudication or radicular symptoms for at least 12 weeks Neurogenic claudication or radicular symptoms for at least 12 weeks Cross sectional imaging confirming dx Cross sectional imaging confirming dx Surgical Candidate Surgical Candidate Exclusion Criteria Exclusion Criteria Spondylolisthesis (studied separately) Spondylolisthesis (studied separately) Instability (4mm translation or 10 degree angulation) Instability (4mm translation or 10 degree angulation) Most patients had received some form of non-surgical tx for their symptoms prior to enrollment (PT 68%, ESI 56%, Chiropractor 28%, NSAIDs 55%, Opioids 27%). Most patients had received some form of non-surgical tx for their symptoms prior to enrollment (PT 68%, ESI 56%, Chiropractor 28%, NSAIDs 55%, Opioids 27%). Weinstein et al. NEJM 2008

SPORT – Lumbar Stenosis After verifying eligibility, patients were allowed to enroll in the randomized or observational cohort. (Observational group avoids ‘enrollment bias’) After verifying eligibility, patients were allowed to enroll in the randomized or observational cohort. (Observational group avoids ‘enrollment bias’) To aid in decision making, patients shown “evidence-based videotapes” with “standardized information” regarding surgical and non-surgical treatments. To aid in decision making, patients shown “evidence-based videotapes” with “standardized information” regarding surgical and non-surgical treatments. Weinstein et al. NEJM 2008

SPORT – Interventions Surgical: “Standard posterior decompressive laminectomy.” Surgical: “Standard posterior decompressive laminectomy.” Non-Surgical: Non-Surgical: “Usual care” “Usual care” “….at least active physical therapy, education or counseling with home exercise instruction, and the administration of non-steroidal antiinflammatory drugs, if tolerated. “….at least active physical therapy, education or counseling with home exercise instruction, and the administration of non-steroidal antiinflammatory drugs, if tolerated. Weinstein et al. NEJM 2008

SPORT – Outcome measures Outcomes of bodily pain and disability Outcomes of bodily pain and disability SF-36, Modified Oswestry Disability Index, other patient indices including overall satisfaction, pain, “Leg pain bothersomeness scale” SF-36, Modified Oswestry Disability Index, other patient indices including overall satisfaction, pain, “Leg pain bothersomeness scale” Follow-up at 6 weeks, 3 months, 6 months, 1 year and 2 years. Follow-up at 6 weeks, 3 months, 6 months, 1 year and 2 years. Effect of treatment was defined as the difference in the mean change from baseline between surgical and non-surgical groups. Effect of treatment was defined as the difference in the mean change from baseline between surgical and non-surgical groups. Weinstein et al. NEJM 2008

SPORT – Patients So far so good…..

SPORT – Patients What really happened.. Randomized Cohort Randomized Cohort Surgical arm: At two years 67% had undergone surgery Surgical arm: At two years 67% had undergone surgery Non-Surgical arm: At two years 43% of patients had crossed over and had surgery. Non-Surgical arm: At two years 43% of patients had crossed over and had surgery. ~55% of the randomized patients had surgery. ~55% of the randomized patients had surgery. ~40% of the randomized pt’s crossed over ~40% of the randomized pt’s crossed over Observational Cohort Observational Cohort Surgical arm: At two years 96% had undergone surgery Surgical arm: At two years 96% had undergone surgery Non Surgical arm: 22% crossed over to surgery Non Surgical arm: 22% crossed over to surgery ~66% of observational patients had surgery ~66% of observational patients had surgery Weinstein et al. NEJM 2008

SPORT – Patients What really happened.. Bottom line: Bottom line: Lots of crossover – the Achilles heal of studies comparing surgery to non-surgical tx. Lots of crossover – the Achilles heal of studies comparing surgery to non-surgical tx. Investigators maintained good follow-up Investigators maintained good follow-up Interesting findings Interesting findings Pt’s in observational cohort had more ‘signs of nerve root tension’ Pt’s in observational cohort had more ‘signs of nerve root tension’ Exhibited a stronger treatment preference Exhibited a stronger treatment preference Group undergoing surgery tended to be younger, more likely to be working, had more pain and lower level of function. Also exhibited ‘more severe’ stenosis on imaging. Group undergoing surgery tended to be younger, more likely to be working, had more pain and lower level of function. Also exhibited ‘more severe’ stenosis on imaging. Weinstein et al. NEJM 2008

SPORT – Patients What really happened.. Non surgical treatment Non surgical treatment Similar between observational and randomized cohorts Similar between observational and randomized cohorts More patients in the randomized group reported visits to a surgeon (45% vs 32%). Also more use of ‘injections’ (52% vs 39%) - ? An attempt to keep them in their randomized group? More patients in the randomized group reported visits to a surgeon (45% vs 32%). Also more use of ‘injections’ (52% vs 39%) - ? An attempt to keep them in their randomized group? More observational patients used ‘other’ medications such as gabapentin More observational patients used ‘other’ medications such as gabapentin Weinstein et al. NEJM 2008

SPORT – Patients What really happened.. Surgical Treatment Surgical Treatment Similar between both groups Similar between both groups Instrumentation in 6% of patients Instrumentation in 6% of patients 9% durotomy rate 9% durotomy rate 8% re-operation rate at 2 years with <50% for recurrent stenosis 8% re-operation rate at 2 years with <50% for recurrent stenosis No mortality directly attributable to surgery No mortality directly attributable to surgery Weinstein et al. NEJM 2008

SPORT – Patients What really happened.. Crossover largely ‘predictable’ Crossover largely ‘predictable’ Pts who crossed over to surgery had more severe symptoms and self-rated disability Pts who crossed over to surgery had more severe symptoms and self-rated disability Pts who crossed over to non-surgical tx had less bothersome sx’s and favored non-surgery at baseline. Pts who crossed over to non-surgical tx had less bothersome sx’s and favored non-surgery at baseline. Observational cohort very similar to randomized group though. Observational cohort very similar to randomized group though. Weinstein et al. NEJM 2008

SPORT How They Analyzed the Data Randomized group: Randomized group: Surgery vs no surgery with ‘intent to treat’ analysis Surgery vs no surgery with ‘intent to treat’ analysis Surgery vs no surgery with ‘as treated’ analysis Surgery vs no surgery with ‘as treated’ analysis Observation group: Observation group: Surgery vs no surgery Surgery vs no surgery Looked at primary outcomes of bodily pain, physical function and mean ODI. Looked at primary outcomes of bodily pain, physical function and mean ODI. Secondary outcome data Secondary outcome data

SPORT What they found Randomized Group Weinstein et al. NEJM 2008

SPORT What they found Observational Group Weinstein et al. NEJM 2008

Statistical Analysis In RCT’s not all patients adhere to protocol they were assigned to. In RCT’s not all patients adhere to protocol they were assigned to. Non compliance Non compliance Crossover Crossover Lost to follow-up / drop-out Lost to follow-up / drop-out This makes your data set imperfect and more difficult to analyze. This makes your data set imperfect and more difficult to analyze. Per protocol analysis – Deviate from protocol and you’re out Per protocol analysis – Deviate from protocol and you’re out Intent to treat analysis – As randomized, so analyzed Intent to treat analysis – As randomized, so analyzed As treated analysis – Analyze based on tx not randomization As treated analysis – Analyze based on tx not randomization

Statistical Analysis Origin of Randomization R.A. Fisher in 1923 studied the effects of different fertilizers on potato yields. R.A. Fisher in 1923 studied the effects of different fertilizers on potato yields. Some fields (or even parts of a field) are more fertile than others though. Some fields (or even parts of a field) are more fertile than others though. Decided to apply the fertilizer to small plots. Decided to apply the fertilizer to small plots. Randomly assign fertilizers to plots/rows. Randomly assign fertilizers to plots/rows. Randomization destroys any connection between soil fertility and treatment. Randomization destroys any connection between soil fertility and treatment.

Statistical Analysis Randomization Any difference between groups that arises after randomization should be due to consequences of the randomized treatment assignment Any difference between groups that arises after randomization should be due to consequences of the randomized treatment assignment Adjusting the analysis of treatment effect by post-randomization group differences could introduce bias Adjusting the analysis of treatment effect by post-randomization group differences could introduce bias

Statistical Analysis Intention to Treat Analysis Includes all randomized patients in the groups to which they were randomly assigned, regardless of their adherence with the entry criteria, regardless of the treatment they actually received, and regardless of subsequent withdrawal from treatment or deviation from the protocol Includes all randomized patients in the groups to which they were randomly assigned, regardless of their adherence with the entry criteria, regardless of the treatment they actually received, and regardless of subsequent withdrawal from treatment or deviation from the protocol (Lloyd) Fisher et al., 1990

Statistical Analysis Intention to Treat Analysis What happens when the crossover is great and there is, in fact, a difference between the two treatments?

Statistical Analysis Intention to Treat Analysis LARD Laparoscopic Antroplasty vs Restricted Diet 1000 patients 1000 patients Inclusion criteria Inclusion criteria Obese - BMI >40 Obese - BMI >40 Surgical Candidate Surgical Candidate Exclusion criteria Exclusion criteria Prior surgical intervention Prior surgical intervention Psychiatric issues Psychiatric issues Randomized to Bariatric Randomized to Bariatric surgery or diet only Beshay et al. Bogus Journal 2010

Statistical Analysis Intention to Treat Analysis LARD Laparoscopic Antroplasty vs Restricted Diet 1000 patients 500 randomized to surgery 500 randomized to diet At the end of the study 350 surgical patients underwent surgery 250 diet patients underwent surgery Beshay et al. Bogus Journal 2010

Statistical Analysis Intent to Treat Analysis LARD Laparoscopic Antroplasty vs Restricted Diet In this study 60% of surgical patients experienced a significant drop in BMI while 30% of diet patients experienced a similar drop In this study 60% of surgical patients experienced a significant drop in BMI while 30% of diet patients experienced a similar drop 1000 patients 500 randomized to surgery 500 randomized to diet 200 patients250 patients ATIT 550 pt’s 330 lost weight 60% 450 pt’s 135 lost weight 30% 500 patients 300 x x 0.3= /500= 48% 500 patients 250 x x 0.3 = 45% Intent to treat analysis with large crossover favors the null hypothesis.

SPORT – Lumbar Stenosis Conclusions Lumbar stenosis is common among elderly patients and is the number one cause of lumbar surgery in those older than 65. Lumbar stenosis is common among elderly patients and is the number one cause of lumbar surgery in those older than 65. When treating neurogenic claudication or radicular symptoms, patients will improve with operative or non- operative strategies When treating neurogenic claudication or radicular symptoms, patients will improve with operative or non- operative strategies There is significantly more improvement with surgical intervention There is significantly more improvement with surgical intervention Surgical intervention in this group of patients was safe Surgical intervention in this group of patients was safe Beware of Intent to Treat Analysis in studies in which there was a large amount of crossover. Beware of Intent to Treat Analysis in studies in which there was a large amount of crossover. Don’t underestimate the value of observational groups. Don’t underestimate the value of observational groups.

Surgical Treatment of Lumbar Stenosis ‘Standard’ open laminectomy/medial facetectomy/foraminotomy – unilateral or bilateral ‘Standard’ open laminectomy/medial facetectomy/foraminotomy – unilateral or bilateral

Surgical Treatment of Lumbar Stenosis Minimally invasive approach Minimally invasive approach Goal is to achieve same results with little muscle disruption Goal is to achieve same results with little muscle disruption Utilize a tubular retractor Utilize a tubular retractor Incision off the midline Incision off the midline Muscle splitting technique Muscle splitting technique

Surgical Treatment of Lumbar Stenosis Minimally invasive approach Minimally invasive approach

Surgical Treatment of Lumbar Stenosis Minimally invasive approach Minimally invasive approach

Surgical Treatment of Lumbar Stenosis Minimally invasive approach Minimally invasive approach

Surgical Treatment of Lumbar Stenosis

Papavero et al. 2009

Surgical Treatment of Lumbar Stenosis Papavero et al. 2009

Surgical Treatment of Lumbar Stenosis Are minimally invasive techniques better? Are minimally invasive techniques better? In experienced hands same results as open surgery In experienced hands same results as open surgery Less hospital stay – modest Less hospital stay – modest Less post op narcotics Less post op narcotics Less muscle disruption as assessed by CK and follow-up MRI Less muscle disruption as assessed by CK and follow-up MRI ? Less post op instability ? – Maybe.. ? Less post op instability ? – Maybe..

Surgical Treatment of Lumbar Stenosis What about interspinous process spacers? What about interspinous process spacers?

Surgical Treatment of Lumbar Stenosis What about interspinous process spacers? What about interspinous process spacers?

Surgical Treatment of Lumbar Stenosis What about interspinous process spacers? What about interspinous process spacers? Do they work? Yes, in selected patients. Do they work? Yes, in selected patients. Kuchta et al. Eur Spine J 2009

Surgical Treatment of Lumbar Stenosis Extension Limiting Devices Extension Limiting Devices

Surgical Treatment of Lumbar Stenosis “Other” “Other” Swei-Ming et al. JNS 2006

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