eO
RIGINAL
ARTICLE
Surgical Outcomes for Painless Drop Foot Due to Degenerative Lumbar Disorders Hiroyuki Aono, MD, PhD,* Yukitaka Nagamoto, MD, PhD,* Hidekazu Tobimatsu, MD,* Shota Takenaka, MD,w and Motoki Iwasaki, MD, PhDz
Study Design: Twenty patients presenting with painless drop foot who had undergone lumbar spine surgery for degenerative lumbar diseases were included in this retrospective study. Objective: This study aims to investigate which causative factors and patient symptoms significantly affected surgical outcome. Summary of Background Data: Drop foot is a neuromuscular condition that results in dorsiflexion palsy of the ankle. Patients with drop foot often complain of leg pain. Rarely, patients experience painless drop foot due to lumbar degenerative disease. For these patients, the only purpose of surgery is to improve the palsy; this makes it difficult to determine whether surgical intervention is indicated. No studies have focused on the results of surgical treatment for painless drop foot caused by degenerative lumbar diseases. Methods: Preoperative strength of the tibialis anterior and duration of palsy were recorded and considered with surgical outcome. Results: Sixty-five percent of patients recovered from drop foot after surgery. Drop foot was caused mainly by impairment of the L5 nerve root. Patients with a longer duration of palsy had poorer results. Conclusions: Duration of palsy had the greatest effect on recovery. As the only goal of this surgery is improvement in the strength of the tibialis anterior, caution must be exercised when considering surgery for patients with longstanding palsy. Key Words: painless drop foot, degenerative lumbar disease, tibialis anterior, gluteus medius, L5 nerve root (J Spinal Disord Tech 2014;27:E258–E261)
D
rop foot, or dorsiflexion palsy of the ankle, is a neuromuscular disorder in which patients experience pain, weakness, and occasionally loss of function. Drop Received for publication January 31, 2014; accepted April 3, 2014. From the *Department of Orthopedic Surgery, Osaka National Hospital; wDepartment of Orthopedic Surgery, Osaka Koseinenkin Hospital; and zDepartment of Orthopedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. The authors declare no conflict of interest. Reprints: Hiroyuki Aono, MD, PhD, Department of Orthopedic Surgery, Osaka National Hospital, 2-1-14 Hoenzaka, Chuo-ku, Osaka 540-0006, Japan (e-mail: [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
E258 | www.jspinaldisorders.com
foot has multiple causes, including peroneal nerve palsy, sciatic nerve palsy, brain lesions,1,2polyneuropathy,3,4 spinal cord lesions in the thoracic-lumbar junction,5,6 and palsy of the lower lumbar root due to degenerative diseases.7–11 Patients with drop foot stumble easily and have difficulty walking in sandals and slippers, which tend to fall off. They also have problem in driving a car as it is difficult to release pedals. Furthermore, claudication caused by drop foot often causes the development of a characteristic steppage gait. In the spine, the most common causes of drop foot are lumbar degenerative diseases such as disk herniation and canal stenosis. Patients with drop foot and a diagnosis of disk herniation or canal stenosis often complain of leg pain. The aim of surgery for these patients is mainly pain relief, not improvement of drop foot. We reported surgical outcomes for drop foot caused by these spinal disorders.7 Painless drop foot due to lumbar degenerative diseases is a rare condition. For patients with this condition, the only purpose of surgery is improvement of the palsy; this makes it difficult to decide whether surgical intervention is indicated. In this study, we retrospectively examined recovery after surgery in patients with painless drop foot caused by degenerative lumbar diseases who underwent decompression with or without fusion surgery. We also identified factors that influenced recovery from drop foot.
MATERIALS AND METHODS Among 94 patients with drop foot who underwent lumbar spine surgery for degenerative lumbar disorders between July 1995 and May 2011, 20 had no leg pain at the time of surgery and were included in this study. There were 12 male and 8 female patients with a mean age of 52 years (range, 27–84 y) at the time of surgery and a mean follow-up period of 3.9 years (range, 2–9 y). Drop foot was unilateral in 19 patients and bilateral in 1 patient. Drop foot was evaluated by determining the muscle strength of the tibialis anterior (TA) using a manual muscle test and characterizing it according to the Medical Research Council scale, as defined in previous study7 (Table 1). A score of
RIGINAL
ARTICLE
Surgical Outcomes for Painless Drop Foot Due to Degenerative Lumbar Disorders Hiroyuki Aono, MD, PhD,* Yukitaka Nagamoto, MD, PhD,* Hidekazu Tobimatsu, MD,* Shota Takenaka, MD,w and Motoki Iwasaki, MD, PhDz
Study Design: Twenty patients presenting with painless drop foot who had undergone lumbar spine surgery for degenerative lumbar diseases were included in this retrospective study. Objective: This study aims to investigate which causative factors and patient symptoms significantly affected surgical outcome. Summary of Background Data: Drop foot is a neuromuscular condition that results in dorsiflexion palsy of the ankle. Patients with drop foot often complain of leg pain. Rarely, patients experience painless drop foot due to lumbar degenerative disease. For these patients, the only purpose of surgery is to improve the palsy; this makes it difficult to determine whether surgical intervention is indicated. No studies have focused on the results of surgical treatment for painless drop foot caused by degenerative lumbar diseases. Methods: Preoperative strength of the tibialis anterior and duration of palsy were recorded and considered with surgical outcome. Results: Sixty-five percent of patients recovered from drop foot after surgery. Drop foot was caused mainly by impairment of the L5 nerve root. Patients with a longer duration of palsy had poorer results. Conclusions: Duration of palsy had the greatest effect on recovery. As the only goal of this surgery is improvement in the strength of the tibialis anterior, caution must be exercised when considering surgery for patients with longstanding palsy. Key Words: painless drop foot, degenerative lumbar disease, tibialis anterior, gluteus medius, L5 nerve root (J Spinal Disord Tech 2014;27:E258–E261)
D
rop foot, or dorsiflexion palsy of the ankle, is a neuromuscular disorder in which patients experience pain, weakness, and occasionally loss of function. Drop Received for publication January 31, 2014; accepted April 3, 2014. From the *Department of Orthopedic Surgery, Osaka National Hospital; wDepartment of Orthopedic Surgery, Osaka Koseinenkin Hospital; and zDepartment of Orthopedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. The authors declare no conflict of interest. Reprints: Hiroyuki Aono, MD, PhD, Department of Orthopedic Surgery, Osaka National Hospital, 2-1-14 Hoenzaka, Chuo-ku, Osaka 540-0006, Japan (e-mail: [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
E258 | www.jspinaldisorders.com
foot has multiple causes, including peroneal nerve palsy, sciatic nerve palsy, brain lesions,1,2polyneuropathy,3,4 spinal cord lesions in the thoracic-lumbar junction,5,6 and palsy of the lower lumbar root due to degenerative diseases.7–11 Patients with drop foot stumble easily and have difficulty walking in sandals and slippers, which tend to fall off. They also have problem in driving a car as it is difficult to release pedals. Furthermore, claudication caused by drop foot often causes the development of a characteristic steppage gait. In the spine, the most common causes of drop foot are lumbar degenerative diseases such as disk herniation and canal stenosis. Patients with drop foot and a diagnosis of disk herniation or canal stenosis often complain of leg pain. The aim of surgery for these patients is mainly pain relief, not improvement of drop foot. We reported surgical outcomes for drop foot caused by these spinal disorders.7 Painless drop foot due to lumbar degenerative diseases is a rare condition. For patients with this condition, the only purpose of surgery is improvement of the palsy; this makes it difficult to decide whether surgical intervention is indicated. In this study, we retrospectively examined recovery after surgery in patients with painless drop foot caused by degenerative lumbar diseases who underwent decompression with or without fusion surgery. We also identified factors that influenced recovery from drop foot.
MATERIALS AND METHODS Among 94 patients with drop foot who underwent lumbar spine surgery for degenerative lumbar disorders between July 1995 and May 2011, 20 had no leg pain at the time of surgery and were included in this study. There were 12 male and 8 female patients with a mean age of 52 years (range, 27–84 y) at the time of surgery and a mean follow-up period of 3.9 years (range, 2–9 y). Drop foot was unilateral in 19 patients and bilateral in 1 patient. Drop foot was evaluated by determining the muscle strength of the tibialis anterior (TA) using a manual muscle test and characterizing it according to the Medical Research Council scale, as defined in previous study7 (Table 1). A score of
